diff --git a/marked/K/T-REC-K.11-200901-I_PDF-E/raw.md b/marked/K/T-REC-K.11-200901-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..152f0321dbe24895043440402e5510fdae3c5427 --- /dev/null +++ b/marked/K/T-REC-K.11-200901-I_PDF-E/raw.md @@ -0,0 +1,705 @@ + + +International Telecommunication Union + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.11** + +(01/2009) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +# --- **Principles of protection against overvoltages and overcurrents** + +Recommendation ITU-T K.11 + +ITU-T + +![ITU logo: A globe with a red lightning bolt striking it, next to the text 'ITU International Telecommunication Union'.](84a1d09fb489061482111515543b60dc_img.jpg) + +ITU logo: A globe with a red lightning bolt striking it, next to the text 'ITU International Telecommunication Union'. + + + +## **Recommendation ITU-T K.11** + +# **Principles of protection against overvoltages and overcurrents** + +## **Summary** + +Recommendation ITU-T K.11 deals with protection principles, e.g., risk management, safety and reliability, surge protective devices and surge protective components. It gives guidance for the protection of telecommunication equipment, installations and cable plants exposed to the results of external sources of interference such as overvoltages and overcurrents due to lightning or effects related to power lines and electric traction systems. + +It gives general information about: + +- the origin of overvoltages and overcurrents (lightning, power induction, power contacts, earth potential rises); +- types of protective devices (voltage-limiting and current-limiting devices) and their residual effects; +- risk assessment; +- protection of telecommunication lines; +- protection of exchange and transmission equipment; +- protection in access networks. + +Reference is made, in the bibliography, to some ITU-T K-series Recommendations and IEC standards related to: + +- power supply effects and low frequency interference; +- lightning effects; +- surge protective devices and components; +- resistibility of telecommunications equipment. + +## **Source** + +Recommendation ITU-T K.11 was approved on 13 January 2009 by ITU-T Study Group 5 (2009-2012) under Recommendation ITU-T A.8 procedures. + +## **Keywords** + +Maintenance, protection, protective measures. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2010 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +# CONTENTS + +| | | Page | +|-----|---------------------------------------------------------------------------|------| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 4 | Abbreviations and acronyms ..... | 3 | +| 5 | General considerations..... | 3 | +| 5.1 | Effects related to power lines and electric traction systems..... | 4 | +| 5.2 | Effects related to lightning effects..... | 5 | +| 5.3 | Methods of protection..... | 5 | +| 5.4 | Surge protective devices and surge protective components ..... | 6 | +| 5.5 | Residual effects ..... | 7 | +| 5.6 | Risk management ..... | 8 | +| 5.7 | Protection principles..... | 9 | +| 5.8 | Decision on protection..... | 10 | +| 6 | Protection of telecommunication lines ..... | 11 | +| 6.1 | Protective measures external to the conductors themselves..... | 11 | +| 6.2 | Special cables and protective systems ..... | 12 | +| 6.3 | Use of protective devices..... | 12 | +| 6.4 | Installation of protective devices ..... | 12 | +| 7 | Protection of exchange and transmission equipment..... | 13 | +| 7.1 | Need for protection external to the equipment..... | 13 | +| 7.2 | Need for equipment to have a minimum level of electrical robustness ..... | 13 | +| 7.3 | Effect of switching conditions..... | 14 | +| 8 | Protection in access networks..... | 14 | +| 8.1 | Degree of exposure..... | 14 | +| 8.2 | Use of SPDs and SPCs ..... | 14 | +| 8.3 | Equipotential bonding ..... | 15 | +| 8.4 | High isolation techniques ..... | 15 | +| 8.5 | National regulations..... | 15 | +| 8.6 | Maintenance of installations..... | 16 | +| | Bibliography..... | 17 | + +# **Introduction** + +Overvoltage protection may be required for safety of persons and for protection of equipment. To provide this protection, it is necessary to interconnect the metallic parts (shield, sheath) along the line and to bond them to the local or building earth, conductors are installed via SPDs at the entrance of the entered structure. This will reduce the risk of injury to people using these services during a.c. fault conditions and during lightning storms. These methods will also provide a level of protection for equipment connected to one or more of these services. + +## Recommendation ITU-T K.11 + +# Principles of protection against overvoltages and overcurrents + +# 1 Scope + +Current ITU-T publications recognize lightning and faults on nearby electrical installations as sources of dangerous disturbances in telecommunication lines, which may cause damage leading to interruptions in service and the need for repairs or even hazards to personnel. + +The objective of this Recommendation is to set out principles which enable the frequency and seriousness of such disturbances to be limited to levels which take account of quality of service, operating costs and safety of personnel. These principles are applicable to all parts of a telecommunications system and cover: + +- power supply effects and low frequency interference; +- lightning effects; +- surge protective devices and components. + +More details on risk calculation, certain methods of protection and protective devices are given in the Recommendations mentioned in the bibliography. + +The telecommunication network to be protected using this Recommendation is limited to telecommunication lines using metallic conductors (buried or aerial cables, shielded or unshielded cables, reference configuration, see [ITU-T K.72]). Responsibilities for protection at customer premises are given in [ITU-T K.66]. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.66] Recommendation ITU-T K.66 (2004), *Protection of customer premises from overvoltages*. +- [ITU-T K.72] Recommendation ITU-T K.72 (2008), *Protection of telecommunication lines using metallic conductors against lightning – Risk management*. +- [IEC 61643-1] IEC 61643-1 (2005), *Low-voltage surge protective devices – Part 1: Surge protective devices connected to low-voltage power distribution systems – Requirements and tests*. +- [IEC 61643-21] IEC 61643-21 (2009), *Low-voltage surge protective devices – Part 21: Surge protective devices connected to telecommunications and signalling networks – Performance requirements and testing methods*. + +ITU-T Recommendations and other documents containing deeper information and provisions, which are relevant to calculate the need of protective measures, the options of protective methods and protective devices are listed in the bibliography. + +# 3 Definitions + +This Recommendation defines the following terms: + +**3.1 active reduction system (ARS):** An active reduction system uses a transformer to compensate for induced voltages in the telecommunication cable system. It operates on the basis that, via a transformer, a voltage with a phase shift by 180°, but of the same amplitude, is coupled into the telecommunication cable to be protected. It consists of a coupling element (iron core with a primary winding, a control winding connected to a pilot conductor, a corresponding number of secondary windings) and an amplifier with a power supply. + +**3.2 inherent protection:** Inherent protection is that protection which is provided at an equipment interface either by virtue of its intrinsic characteristics or by specific design. + +**3.3 maintenance:** Combination of all technical and administrative actions, including supervision actions, intended to retain an item in, or restore it to, a state in which it can perform a required function. + +**3.4 multistage protection:** Multistage protection is the application of sequential protection stages to achieve the intended overall protection level. The location and level of each stage must be coordinated. + +**3.5 passive reduction system (PRS):** A passive reduction system uses a step-down transformer to compensate for induced voltages in a telecommunication cable system. It consists of an iron core with a primary winding (the grounded cable sheath or a pilot conductor) and a corresponding number of secondary windings. In general, the secondary windings are shielded telecommunication cables. + +**3.6 pilot conductor:** Grounded wire, grounded on both sides of the influenced path to get the steering voltage for the control winding of the active reduction system (ARS) or passive reduction system (PRS). + +**3.7 primary protection:** Primary protection is applied using a surge protective device (SPD) to protect an interface or port of an equipment, at the location where it diverts most of the stressful energy from propagation into the equipment. This SPD must be accessible, removable and connected to equipotential bonding. + +**3.8 protection coordination:** Protection coordination is the act of ensuring that all the protection elements, internal and external to the equipment, react in such a way so as to limit the amount of energy, voltage or current to levels such that damage does not occur to protection elements or equipment. + +**3.9 resistibility:** Resistibility is the ability of telecommunication equipment or installations to withstand, in general, without damage, the effects of overvoltages or overcurrents, up to a certain, specified extent, and in accordance with a specified criterion. + +**3.10 secondary protection:** Secondary protection is applied subsequent to the primary protection. It may be provided by inherent protection. + +**3.11 surge protective component (SPC):** Constituent part of a surge protective device which cannot be physically divided into smaller parts without losing its protective function. + +NOTE 1 – This is a modification to definition of item 151-11-21 (component) in the International Electrotechnical Vocabulary [b-IEC 60050-151]. + +NOTE 2 – The protective function is non-linear; amplitude restriction effectively begins when the amplitude attempts to exceed the predetermined threshold value of the component. + +**3.12 surge protective device (SPD):** Device that restricts the voltage of a designated port or ports, caused by a surge, when it exceeds a predetermined level. + +NOTE 1 – An SPD is a combination of a protection circuit and a holder. + +NOTE 2 – Secondary functions may be incorporated, such as current limiting to restrict a terminal current. + +NOTE 3 – Typically, the protection circuit has at least one non-linear voltage-limiting surge protective component. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|---------------------------------------------| +| ABD | Avalanche Breakdown Diode | +| ARS | Active Reduction System | +| BB | Bonding Bar | +| DSL | Digital Subscriber Line | +| EBB | Equipotential Bonding Bar | +| EMC | Electromagnetic Compatibility | +| GDT | Gas Discharge Tube | +| ISDN | Integrated Services Digital Network | +| ITE | Information Technology Equipment | +| MET | Main Earth Terminal | +| MDF | Main Distribution Frame | +| MOV | Metal Oxide Varistor | +| NT | Network Termination | +| OCP | Overcurrent Protector | +| PRS | Passive Reduction System | +| PTC | Positive Temperature Coefficient thermistor | +| RF | Radio Frequency | +| SOP | Semiconductor Overcurrent Protector | +| SPC | Surge Protective Component | +| SPD | Surge Protective Device | +| TSS | Thyristor Surge Suppressor | + +# **5 General considerations** + +When considering protecting a telecommunication network, it is important to determine the probable overvoltage and overcurrent sources and how energy from these sources is coupled into the network, since there are means for reducing the amount of energy coupled into the telecommunication system, the equipment and its installation. + +It is reasonable that the electromagnetic environment should be the major dimensioning factor for protection needs. The electromagnetic environment effect is, on one hand, dependent on the type and probability of the occurrence of the electromagnetic phenomena and, on the other hand, on the physical layout of the system. + +The protective measures shall not decrease the electromagnetic compatibility (EMC) of the system and shall not degrade its intended function as described in the product standards for the system. + +NOTE – EMC means the ability of equipment or system to function satisfactorily in its electromagnetic environment without introducing intolerable electromagnetic disturbances to anything in that environment. + +## **5.1 Effects related to power lines and electric traction systems** + +Depending on the physical process, the effects of high voltage power feeding/transforming or traction systems on a telecommunication system can be divided into: + +- capacitive coupling which represents the effect of an electric field (electric induction); +- inductive coupling which represents the effect of a magnetic field (magnetic induction); +- conductive coupling which represents the effect of a conduction field due to current in the earth. + +These effects may contain multiple components, mainly inductive and conductive coupling. Telecommunication systems with dense electrical integration will be more liable to direct damage due to the reduced creepage distances and clearances. + +For a broad understanding of telecommunication, power and electrified railway facilities, and their mutual coupling effects, consult [b-Handbook II] and [b-Handbook VI]. + +### **5.1.1 Induction from fault currents** + +Induction from fault currents (earth faults) in power lines, including electric traction systems, causes large unbalanced currents to flow along the power line inducing overvoltages into adjacent telecommunication lines which follow a parallel course. The overvoltages may rise to several kilovolts and have durations of 200 to 1000 ms (occasionally even longer) depending on the fault clearing system used on the power line. + +### **5.1.2 Contact with power lines** + +Contact between power and telecommunication lines may occur when local disasters, e.g., storms, fires, cause damage to both types of plant or when the normal safeguards of separation and insulation are not followed. Overvoltages from direct contact of overhead lines rarely exceed 230 V a.c. r.m.s. in countries where this is the common distribution voltage, but may continue for an indefinite period until observed. Where higher distribution voltages (e.g., 2 kV) are used, the power line protection arrangements usually ensure that the voltage is removed in a short time if a fault occurs. The overvoltage may cause excessive currents to flow along the line to the exchange earth causing damage to equipment and danger to staff. + +### **5.1.3 Rise of earth potential** + +Earth faults in power systems cause currents in the soil which raise the potential in the neighbourhood of the fault and of the power supply earth electrode. These earth potentials may affect telecommunication plants in two ways: + +- a) For crossbar switches and equipment whose metallic lines take the ground as their loop, telecommunication signalling systems may malfunction if their earth electrodes are in soil whose potential rises by as little as 5 V with respect to true earth. Such voltages may be caused by minor faults on the power system which may remain undetected for long periods. However, for stored program control switches and equipment taking optical fibre cable as their loop, it is not required to consider the interference caused by potential rise due to faults on the power system. + +NOTE – Such effects of potential rise on program control switches are different from on the crossbar switches and equipment taking the ground as their loop. Adopting optical fibre cables as the media between program control switches avoids interference due to possible potential difference when the metallic lines take the ground as their loop. + +- b) Higher rises of earth potential can cause danger to staff working in the affected area or, in extreme cases, may be sufficient to break down insulation of the telecommunication cable, causing extensive damage. + +## **5.2 Effects related to lightning effects** + +### **5.2.1 Direct lightning strikes** + +Such strikes may cause currents of some thousands of amperes to flow along wires or cables for some microseconds. Physical damage may occur and overvoltage surges of many kilovolts may apply stress to the dielectrics of line plant and terminal equipment. + +### **5.2.2 Lightning strikes nearby** + +Lightning currents flowing from cloud to earth or cloud to cloud cause overvoltages in overhead or underground lines near to the strike. The area affected may be large in districts of high earth resistivity. + +## **5.3 Methods of protection** + +The telecommunication network can be endangered by atmospheric discharge, power influence and power cross. Protective measures must be coordinated with the system to be protected. Protection of the telecommunication network and its service is achieved by following fundamental protection methods: + +- Earthing: Reliable electrical connection of the system with a conductor that provides a low impedance path to the earth (ground) to prevent hazardous voltages from appearing on equipment. Normally, a grounding conductor does not carry current. +- Equipotential bonding: Electrical connection putting various exposed conductive parts and extraneous conductive parts at a substantially equal potential. It is orientated to reduce the earth potential difference between different metallic conductors, equipment and circuits in the case of faults or external interference (such as lightning strike). +- Shielding: Shielding is the process of limiting the flow of electromagnetic fields between two locations, by separating them with a barrier made of conductive material. Typically, it is applied to enclosures, separating the system from the electrical environment. Shielding used to block radio frequency electromagnetic radiation is also known as RF shielding. +- Improving insulation strength: Improvement of the insulation level of the equipment and lines to prevent overvoltage from damaging insulation so as to ensure equipment and personal safety. +- Disconnection: Allocation of the line with a fuse, resettable OCP (PTC, SOP) or switch facility to prevent excessive energy from entering sensitive circuits. +- Current distribution: Installation of an SPD between the lines and/or between lines and earth. SPDs restrict the voltage of a designated port or ports, caused by a surge, when it exceeds a predetermined level. The decision to use surge protective devices (SPDs) is most properly based on an analysis of the risks that are seen by the network or system under consideration. +- Counter voltages: Counter voltages are used to compensate for induced voltages. + +Some of the protective measures for lines which are described in clause 6 have the effect of reducing overvoltages and overcurrents at their source and so reduce the risk of damage to all parts of the system. + +Other protective measures which may be applied to specific parts of the system, as indicated in clauses 6, 7 and 8, can be separated into two classes: + +- the use of protective devices which prevent excessive energy from reaching vulnerable parts either by diverting it (for example, spark gaps) or by disconnecting the line (for example, fuses); +- the use of equipment with suitable dielectric strength, current-carrying capacity and impedance so that it can withstand the conditions applied to it. + +## **5.4 Surge protective devices and surge protective components** + +When considering the application of protective devices and components to a telecommunication system, the probable overvoltage and overcurrent sources, and how energy from these sources is coupled into the network, have to be identified by risk assessment and/or experience. + +Primary and secondary protection should always be coordinated correctly. To ensure that two cascaded SPDs or SPCs and a following SPD or the telecommunications system are coordinated, it might be necessary to select primary protection and secondary protection (or multistage protection) to ensure that the inherent protection of the system is not exceeded (see clause 5.7.6). + +### **5.4.1 Gas discharge tubes** + +Usually, GDTs are used as primary protection connected between each wire of a line and earth or as 3-electrode units between a pair and earth. Their performance may be specified to precise limits to meet system requirements. GDTs operate frequently without degradation if not overloaded. + +In case of direct contact between power lines and telecommunication lines, the GDT might be stationary ignited. To prevent this, the GDT might offer a failsafe function whereby heating is detected by a mechanism that is thermally initiated to short-circuit the electrodes of the GDT. + +NOTE – Air-gap protectors with carbon or metallic electrodes are usually connected between each wire of a line and earth, they limit the voltage which can appear between their electrodes. They are inexpensive but their insulation resistance can fall appreciably after repeated operation and they may require frequent replacement. For that reason, they are nowadays uncommon. + +### **5.4.2 Semi-conductor protective devices** + +Semi-conductor protective devices are usually used as secondary protection, but developments in the technology of these devices have produced some units which may be used as primary protection. Semi-conductor protective devices operate frequently without degradation if not overloaded. + +### **5.4.3 Varistor** + +Usually connected between each wire of a line and earth or across the wires, varistors are nonlinear two-electrode voltage-dependant resistors, whose resistance decrease with increasing voltage. Varistors operate frequently with degradation after repeated transient events. + +### **5.4.4 Fuses** + +Fuses are connected in series with each wire of a line to disconnect when excessive current flows. Simple fuses have a uniform wire which melts. Slow-acting fuses have a uniform wire which melts quickly when a large current flows, and a spring-loaded fusible element which melts gradually and disconnects when lower currents flow for a prolonged time. High level currents of 2 A and prolonged currents of 250 mA are typical operating levels. Fuses should not sustain an arc after operation. Fuses do not give protection against lightning surges and, in districts where such surges are common, fuses of a high rating (up to 20 A) may be necessary to avoid trouble from fuse failures. Such fuses may not give adequate protection against power line contacts. Fuses can also be a source of noise and disconnection faults. Fuses permanently interrupt a circuit when operated and it is necessary to replace them manually. + +### **5.4.5 Heat coils** + +Heat coils are connected in series with each wire of a line. Heat coils either disconnect the line, earth it, or do both, with the earth extended to line. Heat coils have some fusible component and operate when currents of, typically, 500 mA flow for some 200 s. Heat coils permanently interrupt a circuit when operated and it is necessary to replace them manually. + +### **5.4.6 Fusible links** + +Fuseless overvoltage protector assemblies installed on telecommunication lines can be protected against the risk of overheating in the event of a prolonged contact between the telecommunication line and a power distribution line by means of a fusible link. + +A fusible link usually consists of insulated conductors in series with the telecommunication line and located between the exposure to the power line and the protector assembly. The conductors are usually at least two wire gauges smaller than the conductors terminated on the protector assembly and are of a suitable length to avoid a sustained arc if the power system does not de-energize promptly and the conductors fuse. If the fusible link, or part of it, is installed in a building or other location where a fire hazard might occur, it is enclosed within a cable sheath, splice enclosure or other suitable enclosure to contain any arcing that may result if the conductors fuse. + +### **5.4.7 Overcurrent protectors** + +Overcurrent protectors (OCPs) are placed in series with each wire of a line and operate to limit excessive a.c. currents as an open circuit. There are variable impedance devices which, when heated by overload currents, increase their electrical resistance to a very high value. When the overload is removed, the devices will return to their normal condition and permit operation of the line. + +## **5.5 Residual effects** + +The essential purpose of protective measures is to ensure that the major part of the electrical energy arising from a disturbance is not dissipated in a vulnerable part of the installation and does not reach personnel. However, no device exists which has characteristics for suppressing ideally all voltages or currents connected with disturbances, for the following reasons. + +### **5.5.1 Residual overvoltages** + +Account should be taken of: + +- a) voltages which are unaffected by the protective device because they are below its operating level; +- b) transients which pass before the device operates; +- c) residuals which are sustained after the device operates; +- d) transients produced by the operation of the device. + +### **5.5.2 Transverse voltages** + +Protective devices on the two wires of a pair may not operate simultaneously and so a transverse pulse may be produced. Under certain conditions, particularly if the equipment to be protected has a low impedance, operation of one protective device may prevent the operation of the other one and a transverse voltage may remain as long as the longitudinal voltages are on the line. + +### **5.5.3 Effect on normal circuit operation – Coordinated design** + +Sufficient separation should be allowed between the operating voltage of the protective devices and the highest voltage occurring on the line during normal operation. + +Likewise, the normal characteristics (internal impedances) of the protective elements must be compatible with the normal functioning of the installations, which must take account of their possible presence. + +### **5.5.4 Modifying effects** + +SPDs may safeguard one part of a line at the expense of another, e.g., if an MDF fuse operates due to a power line contact, the voltage on the line may rise to full power line voltage when the fuse disconnects the telecommunication's earth. + +Likewise, the operation of an SPD may greatly reduce the equivalent internal impedance of a circuit relative to equipment connected to it, thus permitting the circulation of currents which may cause damage. + +### **5.5.5 Protection coordination** + +For the protection of sensitive equipment, it is sometimes necessary to use more than one protective device, e.g., a fast-operating, low-current device such as a semiconductor and a slower-operating, high-current device such as a gas discharge tube. In such cases, steps must be taken to ensure that, in the event of a sustained overvoltage, the low-current device does not prevent the operation of the high-current device since, if this happens, the smaller device may be damaged, or the interconnecting wiring may conduct excessive current. + +### **5.5.6 Temperature rise** + +SPCs or SPDs should be designed and positioned in such a way that the rise in temperature which occurs when they operate is unlikely to cause damage to property or danger to people. + +### **5.5.7 Circuit availability** + +The circuit being protected may be temporarily or permanently put out of service when a protective device operates. + +### **5.5.8 Fault liability** + +The use of SPDs may cause maintenance problems due to unreliability. They may also prevent some line and equipment testing procedures. + +## **5.6 Risk management** + +The need for protective measures (e.g., protection with SPDs) should be based on a risk assessment considering the probability of overvoltage and overcurrent. The assessment of all parts of the network shall attain a well-coordinated protection of the whole network. This takes into account the consequences of the loss of service for the customer and the network operator, the importance of the system (e.g., hospitals, traffic control), the electromagnetic environment at the particular site (probability of damages) and the cost related to repair. + +### **5.6.1 Assessment of risk** + +The performance of a telecommunications system with respect to overvoltages depends on: + +- the environment, i.e., the magnitude and probability of overvoltages occurring in the line network associated with the system; +- the construction methods used in the line network, see clause 6; +- the resistibility of equipment in the system; + +- the provision of protective devices; +- the quality of the earth system provided for the operation of the protective devices. + +The above aspects have to be taken into account to assess the risk. + +### **5.6.2 Sources of damage** + +In assessing the environment, consideration should be given to the effects mentioned in clauses 5.1 and 5.2. + +The severity of overvoltages due to lightning varies widely in different localities. A high keraunic level and a high soil resistivity increase the risk of direct and nearby lightning strokes. Lightning is the cause of a large proportion of power system faults, induction and rise of earth potential effects are also increased. On the other hand, buried metal plant, such as water pipes, armoured cables, etc., screens telephone cables greatly reduces overvoltages due to lightning or induction. + +- In city centres and in regions of low keraunic activity, experience shows that overvoltages rarely exceed the residual voltages of protective devices and such environments may be classified as "unexposed". Product Recommendations (listed in the bibliography) specify "basic test levels" to be applied to equipment for use in unexposed environments without protection, and these tests give an indication of the most severe environment which can be regarded as unexposed. +- All other environments are classified as "exposed" but this, of course, covers a wide range of conditions including exceptionally exposed situations where a satisfactory service can only be achieved by the use of all available protective measures. Product Recommendations (listed in the bibliography) specify "enhanced test levels" applied to equipment for use in exposed environments. + +In the case of induced voltages and rise of earth potential, the overvoltages can be calculated with the documents indicated in the bibliography (i.e, those that relate to power supply effects and low frequency interference, and lightning effects) which also recommend the maximum values which may be permitted under various conditions. + +### **5.6.3 Fault records** + +The risk of overvoltages and overcurrents might be assessed in the light of experience. It is recommended that fault statistics be kept in a form which is convenient for that purpose. Faults due to overvoltages or overcurrents and faults due to failures of protective components should be separated from each other and from other component faults. + +## **5.7 Protection principles** + +### **5.7.1 Safety principle** + +Protection devices should be able to prevent such faults as fire hazards and/or large-scale communication interruption due to extension of the negative effects of the damage to telecommunication equipment, so as to limit the faults within a range acceptable to operators. + +When designing, installing and using protective devices, it is required to take it into consideration that the temperature rise due to enabling them should not be high enough to damage their attributes or endanger personal safety. + +Radioactive materials or other harmful materials must not be adopted for protective devices. + +### **5.7.2 Reliability principle** + +Effective protection should be realized within a specified reaction time, and for a specified duration, when the protective devices are exposed to the overvoltage and overcurrent conditions described in this Recommendation. Unreliable protection devices may affect communication as well as maintenance and testing for some lines and equipment. + +### **5.7.3 Availability principle** + +Designing, installing and using protection devices should not affect normal running of the equipment under protection. The signal loss during transmission and impedance should be limited to a specified range. In addition, convenient installation, maintenance and replacement should be ensured for protective devices, and the effect on other telecommunication lines should be as little as possible. + +The non-operating current of second level overcurrent protection should be less than that of first level overcurrent protection. + +### **5.7.4 Economy principle** + +The appropriate protection level and economic technical scheme should be selected on the basis of safety and reliability. + +Since any device itself may be the origin of faults, adopting inappropriate protection devices and circuits for excessive protection is not only very wasteful, but also can attenuate system performance. + +### **5.7.5 Principle of hierarchical protection** + +Based on safety and economy principles, determine whether to adopt basic protection (second level protection) only or enhanced protection (including both first and second level protection). + +### **5.7.6 Coordination principle** + +To ensure that two cascaded SPDs, or an SPD and an information technology equipment (ITE) to be protected, are coordinated during overvoltage conditions, the output protective levels from the SPD shall not exceed the input resistibility levels of the followed SPD or the ITE for all known and rated conditions. + +For example, the second level SPD adopts small current devices with fast operation (such as semiconductor protective devices), while first level SPD adopts strong current devices with slower operation (such as gas discharge tubes). In this case, coordination is required to prevent the second level SPD from affecting the operation of first level SPD, as well as from being damaged by overcurrent. + +For overcurrent protection, the output current upon the operation of first level overvoltage protection should be lower than the non-operating current. Besides, the current-limit operation time for the first level overcurrent protection should be less than that of the second level overcurrent protection. + +Normal telecommunication conditions should be appropriately maintained during the implementation of protection circuits or devices. + +## **5.8 Decision on protection** + +In considering the degree to which a telecommunication network should withstand overvoltages, two classes of failure may be recognized: + +- Minor failures affecting only small parts of the system. These may be allowed to occur at a level acceptable to the administration. + +- Major breakdowns, fires, exchange failures, etc., which must, so far as possible, be avoided completely. + +Examples of conditions which may be permitted to cause minor failures but not major breakdowns are given in the product Recommendations (listed in the bibliography). It is desirable also that failure of a single protective device should not cause a major breakdown. Particular attention should be given to overvoltage and overcurrent protection for new types of exchange or customer equipment to ensure that the benefits of its improved facilities are not lost due to unacceptable failures arising from exposure to overvoltages or overcurrents. Such equipment may be inherently sensitive to these conditions and damage or malfunction may affect large parts of a system. It should be noted that over-protection, by the provision of unnecessary protective devices, is not only uneconomic but may actually worsen system performance since the devices themselves may have some liability to cause failures. + +To avoid disturbances in telecommunication circuits caused by activated protective devices, the striking voltage values and the numbers of arresters should be considered. + +In the light of the above considerations and the assessment of risks in accordance with clause 5.6.1, a decision should be made on the protection to be provided in all parts of the system. Account should be taken of commercial considerations such as the cost of protective measures, the cost of repairs, relations with customers and the probable frequency of faults due to overvoltage and overcurrent relative to the fault rate due to other causes. + +The responsibility for making this decision and for ensuring the provision of any protective devices needed to coordinate lines and equipment should be clearly laid down. + +It is necessary for manufacturers of equipment to know the conditions that the equipment will need to resist and for line engineers to know the resistibility of the equipment which will be connected to the lines. The line engineer should also define the constraints which equipment connected to the line will encounter, depending on the standards of line protection provided. Where parts of the network, such as equipment installed in customer premises, lines and telecommunications centres may be under different ownership, this coordination may require formal procedures such as the production of local standards. The Recommendations listed in the bibliography that are related to resistibility of telecommunications equipment give guidance for the preparation of these standards. + +# **6 Protection of telecommunication lines** + +The general considerations of clauses 5.5 and 5.7 apply to the protection of telecommunication lines. It is highly recommended that the protective measures applied to the line should be decided at the outset of a project and should depend on the environment. It may be difficult and expensive to achieve a satisfactory standard of reliability from a line provided initially with insufficient protection. + +Where lines in a telecommunication network are exposed to frequent or severe disturbances from power line faults or lightning, the voltage of these lines relative to local earth potential should be limited either by connecting protective devices between the line conductors and earth or by using appropriate construction methods for the line. + +## **6.1 Protective measures external to the conductors themselves** + +Telecommunication lines may be shielded from lightning and power induction to some extent by adjacent earthed metal structures, e.g., power lines or electric railway systems. Efficient metallic screens either in the form of cable sheaths, cable ducts or lightning guard wires, reduce the effects of lightning surges and power line induction. It is necessary to point out that these metal structures, like the screen of the cable, shall be continuous and connected across all splices along the length of the cable, and shall be connected to the BB, preferably directly or through an SPD (to avoid corrosion problems), at the ends of the cable. + +Induction from power lines may be minimized by coordinating the construction practices for the power and telecommunication lines. The level of induction may be reduced at its source by the installation of earth wires and current limiters in the power system. + +The likelihood of contacts occurring between power lines and telecommunications lines is reduced if agreed standards of construction, separation and insulation are followed. Economic considerations arise, but it is often possible to benefit from jointly using trenches, poles and ducts, providing suitable safe practices are adopted. + +Installing buried telecommunication lines instead of an aerial will halve the risk of damage due to overvoltages. + +## **6.2 Special cables and protective systems** + +Standard plastic insulated and sheathed cables have a higher dielectric strength than paper-insulated, lead-sheathed cables and are suitable for most situations where cables with extra thick insulation were formerly used. The use of cables with strengthened insulation may be justified in situations where there is exceptional proximity or length of parallelism to power lines, high rise of earth potential in the immediate neighbourhood of power stations, or extreme exposure to lightning due to high keraunic level and low soil conductivity. + +Examples of special cables and protective systems are: + +- cables with metal sheaths which provide a good reduction factor to screen circuits within the cable; +- cables which carry circuits to exposed radio towers and which must be able to carry lightning discharge currents without damage; +- all-dielectric (i.e., non-metallic) optical fibre cables to affect isolation between conductive lengths of cable; +- active or passive reduction systems (ARS, PRS). + +## **6.3 Use of protective devices** + +The use of protective devices may be desirable in the following circumstances. + +They may be more economical than the special construction described in clauses 6.1 and 6.2. In this regard, the cost of maintenance should not be overlooked since protective devices inevitably incur some maintenance expenditure whereas special cables, screening, etc., though initially expensive, usually incur no continuing costs. + +Cables with extra thick insulation may themselves be undamaged by overvoltages or overcurrents, but they can nevertheless conduct such conditions to other more vulnerable parts of the network. Extra protection is then required for the more vulnerable cables, which is particularly important if these are large underground cables which are expensive to repair and affect service to many customers. + +Induced overvoltages from power or traction line faults may still exceed levels permitted by the Directives (see bibliography entries that relate to power supply effects and low frequency interference) even after all practicable avoidance measures have been followed. + +## **6.4 Installation of protective devices** + +To protect conductor insulation, it is beneficial to bond all metal sheaths, screens, etc., together, and to connect overvoltage protectors between the conductors and this bonded metal which should be connected to earth. This technique is particularly useful in districts of high soil resistivity as it avoids the need for expensive electrode systems for the protector-earth connection. + +Where protectors are used to reduce high voltages appearing in telecommunication lines due to induction from power line fault currents, they should be fitted to all wires at suitable intervals and at both ends of the affected length of line, or as near to this as practicable. + +To protect underground cables against lightning surges, protective devices may be placed at the points of connection to overhead lines. The protective devices fitted at the MDF and at customers' terminals reduce the risk of damage to lines, but their main function is to protect components having lower dielectric strength than the cables. + +Connections for lines and earth to overvoltage protectors used against lightning should be as short as possible to minimize surge voltage levels between lines and the equipotential bond point. + +# **7 Protection of exchange and transmission equipment** + +## **7.1 Need for protection external to the equipment** + +Network operators should take account of the possible need to fit protection external to the equipment, bearing in mind the considerations given below. + +A telecommunication line will give some protection to equipment under certain conditions, e.g.: + +- a conductor may melt and disconnect an excessive current; +- conductor insulation may break down and reduce an overvoltage; +- air-gaps in connection devices may break down and reduce overvoltages. + +The robustness of plastic insulated cables has the effect of increasing the levels of overvoltages and overcurrents which can occur in the lines and be applied to equipment. By contrast, the use of miniature electronic components in telecommunication equipment tends to increase its vulnerability to electrical disturbances. + +For these reasons, in districts exposed to frequent and serious disturbances (lightning, power lines, soil of low conductivity), it is usually necessary to interpose protective devices of the types described in clause 5.4 between the cable conductors and the equipment to which they are connected, preferably on the MDF. This will prevent cables from the MDF to equipment from having to carry heavy overcurrents. + +The protective devices are fitted to the line side of the MDF to avoid the need to carry discharge currents in the MDF jumper field and to expose as little of the MDF wiring and terminal strips as possible to mains voltage in the event that a mains voltage line contact causes a series protective device to disconnect the line. + +In less exposed locations, it may be that disturbances (voltages and currents) have statistical characteristics of level and frequency so low that in practice the risks do not exceed those resulting from the residual effects indicated in clause 5.5 for exposed regions. Protective devices then serve no purpose and are an unnecessary expense. + +## **7.2 Need for equipment to have a minimum level of electrical robustness** + +In locations where lines are exposed and protective devices are provided, the residual effects can cause overvoltages and overcurrents to appear in the equipment. In less exposed environments, the disturbances described in clause 7.1 can cause similar effects. It is necessary for equipment to be designed to withstand these conditions, and detailed Recommendations on the resistibility which telecommunication equipment should possess are listed in the bibliography. + +## **7.3 Effect of switching conditions** + +Since the configuration and interconnection of equipment connected to a given line is required to vary during the successive stages of connecting a call, it is important not to limit the study of protection solely to individual line equipment. Much equipment is common to all lines and can be exposed to disturbances when connected to a particular line. + +The effectiveness of the protection provided can be influenced by the reduction in the probability of exposure if the effective duration of the connection to lines is short. On the other hand, common equipment should be better protected since its failure risks more serious degradation in the performance of the service. + +# **8 Protection in access networks** + +The increasing use and interconnection of complex electronic telecommunication equipment, such as ISDN terminals, modems and computers, at customers' buildings and xDSL equipment in curbs, requires special care for protecting against overvoltages and overcurrents. Such overvoltages and overcurrents include exposure of the serving telecommunication cable and power line to lightning, and the coupling of a.c. voltages onto the telecommunication cable due to faults on the external power system. Properly configured equipotential bonding within the structure helps to achieve the necessary protection, while also helping to ensure the safety of those using the equipment. + +It is reasonable that the electromagnetic environment should be the major dimensioning factor for protection needs, and not its ownership. The electromagnetic environment effect is, on one hand, dependent on the type and probability of the occurrence of the electromagnetic phenomena and, on the other hand, on the physical layout of the equipment installation. + +## **8.1 Degree of exposure** + +Lines to installations near exchanges in urban or industrial zones are usually little exposed to surges on account of the screening effect of numerous nearby metallic structures as described in clause 6.1. + +On the other hand, lines to installations remote from built-up areas can be very exposed on account of their length, the absence of a protective environment, overhead construction at the customer's end and the high resistivity of the soil. The mechanical robustness of the overhead cables at the customer's end makes the effect of surges all the more serious since the line itself can carry higher voltages and currents. + +## **8.2 Use of SPDs and SPCs** + +### **8.2.1 Use of voltage limiting devices** + +Where telecommunication lines are exposed to frequent and severe disturbances from power line faults or lightning, the voltage of the lines relative to local earth potential should be limited by connecting SPDs or SPCs between the line conductors and the earth terminal, see clause 5.4. + +The terminal equipment dielectric strength should be chosen taking account of the breakdown voltage of the protective device and the impedance of the protector line to earth connection. + +### **8.2.2 Use of high voltage isolation devices** + +Where protected telecommunication lines: + +- 1) exhibit excessive trouble reports due to lightning activity; or +- 2) cannot have overvoltage or overcurrent protection installed for whatever reason; or +- 3) when access to the premises by plant maintenance personnel is difficult; + +then high voltage (up to 50 kV) isolation, together with other suitable measures such as protection to be applied at the drop point from the telecommunications cable, may well be considered. + +The isolation elements should be installed as close as possible to the customer premises on the outside. They must not be mounted inside buildings. + +Isolation techniques may also be helpful at the telecommunication input to high voltage plant (for example, by means of isolation transformers), and in other situations where communications are vital and high plant voltages are probable. + +### **8.2.3 Multiservice surge protective devices** + +Multiservice surge protective devices consist of a combination of protection circuits in a single enclosure for at least two different services (e.g., telecommunication and power supply), which limits the surge voltages to the equipment and provides equipotential bonding between the different services. The surge voltage protection circuits of combined protective devices shall comply with the requirements of [IEC 61643-1] for the power supply circuit, and with [IEC 61643-21] for the telecommunications/signalling circuits. + +## **8.3 Equipotential bonding** + +Overvoltage protection has been required for terminal equipment that has been traditionally under the network operators' responsibility. Due to liberalization in telecommunications, the customer may now own this type of equipment. Electrical installations of buildings are a part of the protection for safety and are under the responsibility of the building owner, this includes the existence of EBB to achieve effective protection. The responsibilities for protective measures are now shared between the network operator and the customer. Most of the practices required to achieve effective protection are beyond the control of the network operator. This may be the responsibility of other parties, e.g., the building owner or the customer. + +In some countries, connection to the electricity system neutral is governed by national regulations, so that agreement with the electrical authority should be obtained. + +In the course of the maintenance of the telecommunication plant, equipotential bonding (connection to the EBB or MET) has to be inspected. + +## **8.4 High isolation techniques** + +When telecommunication lines are located in areas with a very high level of exposure to lightning (frequent breakdowns on lines and also high probability on the terminal installations) and when lightning protectors cannot be installed on the customer plant owing to earthing and maintenance difficulties and costs, it is recommended to employ a high isolation technique (of a level of at least 20 kV) at the telephone line access by transformer isolator or short fibre links. + +This method should be widely introduced at the input to high-voltage plant and is strongly recommended. + +## **8.5 National regulations** + +Many countries have national standards covering the protection of users of telecommunication equipment not only from the risks associated with connection to the electricity mains but also from conditions which may appear on the telecommunication line. + +## **8.6 Maintenance of installations** + +The maintenance requirements of customer installations may be high by reason of the distance from the maintenance centre, transport delays and, possibly, the seriousness of the damage. Moreover, insufficient protection is the cause of repeated interruptions of service which are particularly damaging to the quality of service and to the satisfaction of the customer. This justifies the granting of special attention to the maintenance of the protective measures that might become necessary in the following cases: + +- repeated appearance of damage caused by electrical sources; +- later erection of exposed structures; +- later erection or changes of electric power plants/traction systems; +- change of the operating currents in existing power plants/traction systems; +- customer or authority request. + +The maintenance of the interconnection of cable screens and the earthing of the screen at both ends, including equipotentialization of the system together with remote steerable protective systems, is seen as the most effective measure to reduce maintenance costs. + +# Bibliography + +- [b-ITU-T Guide] ITU-T Reference Document (2008), *Guide to the use of ITU-T publications produced by Study Group 5 aimed at achieving electromagnetic compatibility and safety.* + +## **ITU-T Recommendations related to power supply effects and low frequency interference** + +- [b-ITU-T K.5] Recommendation ITU-T K.5 (1988), *Joint use of poles for electricity distribution and for telecommunications.* +- [b-ITU-T K.6] Recommendation ITU-T K.6 (1988), *Precautions at crossings.* +- [b-ITU-T K.8] Recommendation ITU-T K.8 (1988), *Separation in the soil between telecommunication cables and earthing system of power facilities.* +- [b-ITU-T K.9] Recommendation ITU-T K.9 (1988), *Protection of telecommunication staff and plant against a large earth potential due to a neighbouring electric traction line.* +- [b-ITU-T K.13] Recommendation ITU-T K.13 (1988), *Induced voltages in cables with plastic-insulated conductors.* +- [b-ITU-T K.14] Recommendation ITU-T K.14 (1988), *Provision of a metallic screen in plastic-sheathed cables.* +- [b-ITU-T K.19] Recommendation ITU-T K.19 (1988), *Joint use of trenches and tunnels for telecommunication and power cables.* +- [b-ITU-T K.26] Recommendation ITU-T K.26 (1988), *Protection of telecommunication lines against harmful effects from electric power and electrified railway lines.* +- [b-ITU-T K.29] Recommendation ITU-T K.29 (1992), *Coordinated protection schemes for telecommunication cables below ground.* +- [b-ITU-T K.50] Recommendation ITU-T K.50 (2000), *Safe limits of operation voltages and currents for telecommunication systems powered over the network.* +- [b-ITU-T K.54] Recommendation ITU-T K.54 (2004), *Conducted immunity test method and level at fundamental power frequencies.* +- [b-Handbook II] ITU-T Handbook (1999), *Directives concerning the protection of telecommunication lines against harmful effects from electric power and electrified railway lines; Volume II: Calculating induced voltages and currents in practical cases.* +- [b-Handbook VI] ITU-T Handbook (2008), *Directives concerning the protection of telecommunication lines against harmful effects from electric power and electrified railway lines; Volume VI: Danger, damage and disturbance.* +- [b-Handbook VII] ITU-T Handbook (1989), *Directives concerning the protection of telecommunication lines against harmful effects from electric power and electrified railway lines; Volume VII: Protective measures and safety precautions.* + +## ITU-T Recommendations related to lightning effects + +- [b-ITU-T K.25] Recommendation ITU-T K.25 (2000), *Protection of optical fibre cables.* +- [b-ITU-T K.29] Recommendation ITU-T K.29 (1992), *Coordinated protection schemes for telecommunication cables below ground.* +- [b-ITU-T K.39] Recommendation ITU-T K.39 (1996), *Risk assessment of damages to telecommunication sites due to lightning discharges.* +- [b-ITU-T K.40] Recommendation ITU-T K.40 (1996), *Protection against LEMP in telecommunications centres.* +- [b-ITU-T K.46] Recommendation ITU-T K.46 (2008), *Protection of telecommunication lines using metallic symmetric conductors against lightning-induced surges.* +- [b-ITU-T K.47] Recommendation ITU-T K.47 (2008), *Protection of telecommunication lines using metallic conductors against direct lightning discharges.* +- [b-ITU-T K.56] Recommendation ITU-T K.56 (2003), *Protection of radio base stations against lightning discharges.* +- [b-ITU-T K.57] Recommendation ITU-T K.57 (2003), *Protection measures for radio base stations sited on power line towers.* +- [b-ITU-T K.67] Recommendation ITU-T K.67 (2006), *Expected surges on telecommunications and signalling networks due to lightning.* +- [b-ITU-T Lightning] ITU-T Handbook (1994), *The Protection of Telecommunication Lines and Equipment Against Lightning Discharges.* + +## ITU-T Recommendations related to surge protective devices and components + +- [b-ITU-T K.12] Recommendation ITU-T K.12 (2006), *Characteristics of gas discharge tubes for the protection of telecommunications installations.* +- [b-ITU-T K.28] Recommendation ITU-T K.28 (1993), *Characteristics of semi-conductor arrester assemblies for the protection of telecommunications installations.* +- [b-ITU-T K.30] Recommendation ITU-T K.30 (2004), *Self-restoring overcurrent protectors.* +- [b-ITU-T K.36] Recommendation ITU-T K.36 (1996), *Selection of protective devices.* +- [b-ITU-T K.55] Recommendation ITU-T K.55 (2002), *Overvoltage and overcurrent requirements for insulation displacement connectors (IDC) terminations.* +- [b-ITU-T K.65] Recommendation ITU-T K.65 (2004), *Overvoltage and overcurrent requirements for termination modules with contacts for test ports or SPDs.* +- [b-ITU-T K.69] Recommendation ITU-T K.69 (2006), *Maintenance of protective measures.* +- [b-Handbook VIII] ITU-T Handbook (1989), *Directives concerning the protection of telecommunication lines against harmful effects from electric power and electrified railway lines; Volume VIII: Protective devices.* + +NOTE – ITU-T is considering the publication of guidance on the application of protective devices and/or components in telecommunication installations. + +### **Other documents related to surge protective devices and components** + +- [b-IEC 61643-311] IEC 61643-311 (2001), *Components for low-voltage protective devices – Part 311: Specification for gas discharge tubes (GDT)*. +- [b-IEC 61643-321] IEC 61643-321 (2001), *Components for low-voltage protective devices – Part 321: Specification for avalanche breakdown diode (ABD)*. +- [b-IEC 61643-331] IEC 61643-331 (2003), *Components for low-voltage surge protective devices – Part 331: Specification for metal oxide varistors (MOV)*. +- [b-IEC 61643-341] IEC 61643-341 (2001), *Components for low-voltage surge protective devices – Part 341: Specification for thyristor surge suppressors (TSS)*. + +## **ITU-T Product Recommendations related to resistibility of telecommunications equipment** + +- [b-ITU-T K.20] Recommendation ITU-T K.20 (2003), *Resistibility of telecommunication equipment installed in a telecommunications centre to overvoltages and overcurrents*. +- [b-ITU-T K.21] Recommendation ITU-T K.21 (2003), *Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents*. +- [b-ITU-T K.44] Recommendation ITU-T K.44 (2003), *Resistibility tests for telecommunication equipment exposed to overvoltages and overcurrents – Basic Recommendation*. +- [b-ITU-T K.45] Recommendation ITU-T K.45 (2003), *Resistibility of telecommunication equipment installed in the access and trunk networks to overvoltages and overcurrents*. + +### **Other documents on general topics** + +- [b-IEC 60050-151] IEC 60050-151 (2001), *International Electrotechnical Vocabulary – Part 151: Electrical and magnetic devices*. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|---------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | 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ports** + +Recommendation ITU-T K.117 + +![ITU logo](6ed175c791b5e156d9c98a8dbcc3318c_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a red lightning bolt striking it, symbolizing telecommunications and protection against interference. To the right of the globe, the text "International Telecommunication Union" is written in a blue sans-serif font, with "ITU" in a larger, bold font above it. + +ITU logo + +International +Telecommunication +Union + + + +## Recommendation ITU-T K.117 + +## Primary protector parameters for the surge protection of equipment Ethernet ports + +## Summary + +Recommendation ITU-T K.117 specifies the common-mode, differential mode and common mode to differential mode conversion surge parameter and test circuit requirements of an Ethernet port primary protector. The preferred surge generator voltage levels are 2.5 kV, 6 kV and 12 kV, but the test circuits can be used for any surge voltage environmental. Power over Ethernet (PoE) feed requirements are also given. Ethernet signal performance parameters are not covered and standards such as [b-IEC 60603-7-7] may be used for this purpose. + +This Recommendation should be used for the harmonization of existing or future specifications issued by Ethernet surge protective device (SPD) manufacturers, telecommunication equipment manufacturers, administrations or network operators. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.117 | 2016-12-14 | 5 | 11.1002/1000/13133 | + +## Keywords + +Ethernet, in-line SPD, insulation resistance, overvoltage protector, Power over Ethernet (PoE), primary protector, surge protective device (SPD). + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2017 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 3 | +| 4 Abbreviations and acronyms ..... | 3 | +| 5 Conventions ..... | 3 | +| 5.1 Connections ..... | 3 | +| 5.2 Protective function..... | 4 | +| 6 Electrical parameters ..... | 4 | +| 6.1 Common-mode surge ..... | 5 | +| 6.2 Differential-mode surge..... | 6 | +| 6.3 Common-mode to differential-mode surge conversion..... | 9 | +| 6.4 Surge durability (optional) ..... | 11 | +| 6.5 Cable screen terminal ..... | 11 | +| 7 DC tests..... | 12 | +| 7.1 Insulation resistance ..... | 12 | +| 7.2 DC voltage drop ..... | 13 | +| 8 Identification..... | 14 | +| 8.1 Marking ..... | 14 | +| 8.2 Documentation ..... | 14 | +| 9 Ordering information ..... | 14 | +| Bibliography..... | 15 | + + + +## Recommendation ITU-T K.117 + +## Primary protector parameters for the surge protection of equipment Ethernet ports + +# 1 Scope + +This Recommendation applies to surge protective devices (SPDs) to be used for Ethernet primary protection in surge voltage environments with a peak value of 2.5 kV and above. It covers the following device parameters: + +- a) electrical surge +- b) electrical d.c. +- c) identification and marking. + +This Recommendation does not deal with: + +- a) mountings for SPDs and their effect on characteristics; +- b) mechanical dimensions; +- c) quality assurance requirements; +- d) units containing current limiters; +- e) signal performance parameters, standards such as [b-IEC 60603-7-7] may be used for this purpose; +- f) diagnostic properties such as indicators and status monitor outputs. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T K.44] Recommendation ITU-T K.44 (2016), *Resistibility tests for telecommunication equipment exposed to overvoltages and overcurrents – Basic Recommendation*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 common-mode conversion** [b-ITU-T K.96]: Process by which a differential mode electrical signal is produced in response to a common mode electrical signal. + +NOTE – This definition is based on the definition provided in [b-IEC 60050-161]. + +**3.1.2 common-mode surge** [b-ITU-T K.96]: Surge appearing equally on all conductors of a group at a given location. + +NOTE 1 – The reference point for common-mode surge voltage measurement can be a chassis terminal, or a local earth/ground point. + +NOTE 2 – Also known as longitudinal surge or asymmetrical surge. + +- 3.1.3 connector** [b-IEC 14776-153]: Electro-mechanical components consisting of a receptacle and a plug that provide a separable interface between two transmission segments. +- 3.1.4 differential-mode surge** [b-ITU-T K.96]: Surge occurring between any two conductors or two groups of conductors at a given location. +- NOTE 1 – The surge source maybe be floating, without a reference point or connected to reference point, such as a chassis terminal, or a local earth/ground point. +- NOTE 2 – Also known as metallic surge or transverse surge or symmetrical surge or normal surge. +- 3.1.5 hard-wired** [b-IEC 60601-2-1]: Term used where the features of a system can be modified only by physically removing and re-routing wires. +- 3.1.6 insulation** [b-IEC 60664-2-1]: That part of an electrotechnical product which separates the conducting parts at different electrical potentials. +- 3.1.7 isolating transformer** [b-IEC 60065]: Transformer with protective separation between the input and output windings. +- NOTE – Isolating transformers can be divided into three groups; mains, switched mode and signal (e.g., Ethernet data). +- 3.1.8 impulse limiting voltage, $V_P$** [b-ITU-T K.28]: Highest value of voltage across the terminals of the SPD during the application of a specified impulse. +- NOTE – Also called voltage protection level or measured limiting voltage. +- 3.1.9 in-line SPD** [b-ITU-T K.28]: A two-port SPD connected in series with the service feed. +- 3.1.10 insulation resistance (effective)** [b-ITU-T K.28]: Quotient of the voltage applied to a designated terminal pair, $V_{IR}$ , by the current, $I_{IR}$ , drawn from the applied voltage. +- 3.1.11 impulse generator charge voltage, $V_C$** [b-ITU-T K.82]: Value of impulse generator charging voltage. +- 3.1.12 impulse withstand voltage** [b-IEC 60664-2-1]: Highest peak value of impulse voltage of prescribed form and polarity applied to a circuit or equipment, which does not cause degradation or result in breakdown or flashover. +- 3.1.13 let-through current** [b-ITU-T K.28]: In-line SPD peak short-circuit output current when a specified impulse is applied to the SPD input. +- 3.1.14 overvoltage** [b-IEC 60664-2-1]: Any voltage having a peak value exceeding the corresponding peak value of maximum steady-state voltage at normal operating conditions. +- 3.1.15 parameter** [b-IEC 61643-341]: Device descriptor that is measurable or quantifiable, such as a characteristic or rating. +- 3.1.16 port** [b-IEC 60050-131]: Access to a device or network where electromagnetic energy or signals may be supplied or received or where the device or network variables may be observed or measured. +- NOTE – An example of a port is a terminal pair. +- 3.1.17 primary protection** [ITU-T K.44]: Means by which the majority of the surge stress is prevented from propagating beyond a designated location (preferably the building entrance point). +- 3.1.18 rated peak impulse current** [b-ITU-T K.28]: Maximum value of peak impulse current of specified amplitude and waveshape that may be applied without causing degradation. +- 3.1.19 sparkover** [b-IEC 60050-212]: Disruptive discharge in a gaseous or liquid insulating material. +- 3.1.20 surge** [b-ITU-T K.96]: Temporary disturbance on the conductors of an electrical service caused by an electrical event not related to the service. + +NOTE – For non-linear SPCs a surge event is defined as an overvoltage or overcurrent or both. + +**3.1.21 surge protective component (SPC)** [b-ITU-T K.96]: Component specifically included in a device or equipment for the mitigation of the onward propagation of overvoltages or overcurrents or both. + +**3.1.22 surge protective device (SPD)** [b-ITU-T K.96]: Device that mitigates the onward propagation of overvoltages or overcurrents or both. + +**3.1.23 two-port** [b-IEC 60050-131]: Device or network with two separate ports. + +## **3.2 Terms defined in this Recommendation** + +None. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|----------------------------| +| GDT | Gas Discharge Tube | +| IR | Insulation Resistance | +| PD | Powered Device/equipment | +| PE | Protective Earth | +| PoE | Power over Ethernet | +| PSE | Power Sourcing Equipment | +| RJ45 | Registered Jack #45 | +| SPC | Surge Protective Component | +| SPD | Surge Protective Device | + +# **5 Conventions** + +## **5.1 Connections** + +The connection designation used in this Recommendation corresponds to the normal Ethernet cable RJ45 contacts. Figure 1 shows the RJ45 contact numbers that are associated with signal connections and the PoE power feed modes. When an SPD does not use a RJ45 receptacle but uses, for example, a hard-wired cable connection, the terminal notations may be different. A hard-wire connector may be required when the RJ45 contact currents exceed 1 kA or voltages between adjacent contacts will exceed 4 kV. The SPD configuration is assumed as in-line (2 port) with the test being applied to one port and the let-through surge measured on the other terminated port. + +![Diagram of Ethernet RJ45 contact connections. On the left, four twisted-pair signals are labeled: (1, 2), (3, 6), (4, 5), and (7, 8). These connect to pins 1 through 8. Pins 1, 2, 3, and 6 are grouped together on the right as '1, 2 and 3, 6 PoE mode A powering feed pair'. Pins 4, 5, 7, and 8 are grouped as '4, 5 and 7, 8 PoE mode B powering feed pair'. At the bottom, a 'Cable screen if present' connects to a 'Screen' terminal, which is then connected to 'Protective earth /common'. The diagram is labeled K.117(16)_F01.](a5ee5c23b6dc52ec1d724b76d5a5f58f_img.jpg) + +Diagram of Ethernet RJ45 contact connections. On the left, four twisted-pair signals are labeled: (1, 2), (3, 6), (4, 5), and (7, 8). These connect to pins 1 through 8. Pins 1, 2, 3, and 6 are grouped together on the right as '1, 2 and 3, 6 PoE mode A powering feed pair'. Pins 4, 5, 7, and 8 are grouped as '4, 5 and 7, 8 PoE mode B powering feed pair'. At the bottom, a 'Cable screen if present' connects to a 'Screen' terminal, which is then connected to 'Protective earth /common'. The diagram is labeled K.117(16)\_F01. + +**Figure 1 – Ethernet RJ45 contact connections** + +## 5.2 Protective function + +This Recommendation tries to be technology neutral on the surge protective components (SPCs) used in the SPD. SPDs using voltage limiting components or isolating components, or both are tested with the SPD terminated. Figures 2 and 3 show examples of a voltage limiting gas discharge tube (GDT) and isolating transformer in a common-mode surge test with the termination connected. + +![Circuit diagram for GDT common-mode voltage limiting. A surge pulse is applied to the input of an SPD block containing a GDT symbol. The output of the SPD connects to a termination circuit. The termination circuit consists of two 1 Ω resistors in series with a 10 nF capacitor connected between the lines. Additionally, there is a 75 Ω resistor in parallel with a 1 nF capacitor connected to ground. The diagram is labeled K.117(16)_F02.](daa4a6fa7e2ba1954258f86b4928eb32_img.jpg) + +Circuit diagram for GDT common-mode voltage limiting. A surge pulse is applied to the input of an SPD block containing a GDT symbol. The output of the SPD connects to a termination circuit. The termination circuit consists of two 1 Ω resistors in series with a 10 nF capacitor connected between the lines. Additionally, there is a 75 Ω resistor in parallel with a 1 nF capacitor connected to ground. The diagram is labeled K.117(16)\_F02. + +**Figure 2 – GDT common-mode voltage limiting +(partial circuit for only one twisted pair)** + +![Circuit diagram for isolating transformer common-mode voltage blocking. A surge pulse is applied to the input of an SPD block containing an isolating transformer symbol. The output of the SPD connects to the same termination circuit as in Figure 2: two 1 Ω resistors, a 10 nF capacitor, a 75 Ω resistor, and a 1 nF capacitor. The diagram is labeled K.117(16)_F03.](053f1077d592e6622cd21dc4bb4cb366_img.jpg) + +Circuit diagram for isolating transformer common-mode voltage blocking. A surge pulse is applied to the input of an SPD block containing an isolating transformer symbol. The output of the SPD connects to the same termination circuit as in Figure 2: two 1 Ω resistors, a 10 nF capacitor, a 75 Ω resistor, and a 1 nF capacitor. The diagram is labeled K.117(16)\_F03. + +**Figure 3 – Isolating transformer common-mode voltage blocking +(partial circuit for only one twisted pair)** + +# 6 Electrical parameters + +The objective of an Ethernet SPD is to mitigate the cable surge levels down to levels that the equipment port can withstand. Cable surges can be common mode or differential mode. In addition + +the SPD must not generate an excessive differential surge in common-mode surge operation; see Tables 2 and 3 for preferred maximum differential surge values. + +Three [b-IEC 60664-2-1] preferred values of generator charging voltage are used: 2.5 kV, 6 kV and 12 kV. Manufacturers may also define levels to suit specific applications. SPDs rated for 2.5 kV are intended to protect equipment ports that do not meet a basic port withstand voltage of 2.5 kV. SPDs rated for 6 kV are intended to protect equipment ports that have a basic port withstand voltage of 2.5 kV but the equipment has been installed in an environment that requires an enhanced 6 kV capability. SPDs rated for 12 kV are intended for severe installation environments to protect equipment ports that only have the basic (2.5 kV) or enhanced (6 kV) withstand voltages. + +The testing assumes all 8 Ethernet conductors are protected. Where the SPD is designed to protect a lesser number of conductors and surge mode requirements (e.g. non-PoE) only the appropriate SPD equipment terminals are tested and measured. + +## 6.1 Common-mode surge + +The purpose of this test is to measure the impulse limiting voltage at the SPD port connecting to the equipment Ethernet port. The test circuit is shown in Figure 4. To test this, set the generator charge voltage to the required level from Table 1 and surge the SPD while recording an SPD equipment port terminal voltage. Record the terminal peak voltage measured. Repeat this test with the generator voltage polarity reversed. Repeat this procedure until all the port terminals have been measured for positive and negative surges and their peak voltage values have been recorded. For each configuration a minimum of three surges must be applied and the recorded value is the highest measured value. Finally, measure the d.c. insulation resistance for terminals 1 to 8 of the SPD cable port, as described in clause 7.1. + +![Figure 4 – Impulse limiting voltage under common-mode surge conditions. The diagram shows a test circuit for measuring impulse limiting voltage. On the left, a 1.2/50-8/20 combination wave generator is connected to the SPD's cable port (terminals 1, 2, 3, 4, 5, 6, 7, 8) through a resistor R9 = 5 Ω. The generator's return/earth is connected to a reference bar (point 'a'). The SPD has an equipment port (terminals 1, 2, 3, 4, 5, 6, 7, 8) connected to a termination circuit. The termination circuit consists of eight resistors (R1 to R8 = 1 Ω) in series with capacitors (C1 to C4 = 10 nF, 300 V) and resistors (R11 to R14 = 75 Ω). The termination circuit is connected to a reference bar (point 'c') and a 1 nF 3 kV capacitor (C5) connected to ground (point 'd'). The SPD's screen is connected to the reference bar (point 'b').](7e670a2b556b53ea9002dfff3a420e08_img.jpg) + +Figure 4 shows the test circuit for measuring impulse limiting voltage under common-mode surge conditions. The circuit includes a 1.2/50-8/20 combination wave generator connected to the SPD's cable port (terminals 1, 2, 3, 4, 5, 6, 7, 8) through a resistor $R9 = 5 \Omega$ . The generator's return/earth is connected to a reference bar (point 'a'). The SPD has an equipment port (terminals 1, 2, 3, 4, 5, 6, 7, 8) connected to a termination circuit. The termination circuit consists of eight resistors ( $R1$ to $R8 = 1 \Omega$ ) in series with capacitors ( $C1$ to $C4 = 10 \text{ nF}$ , 300 V) and resistors ( $R11$ to $R14 = 75 \Omega$ ). The termination circuit is connected to a reference bar (point 'c') and a 1 nF 3 kV capacitor ( $C5$ ) connected to ground (point 'd'). The SPD's screen is connected to the reference bar (point 'b'). + +Component values: + $R1$ to $R8 = 1 \Omega$ + $C1$ to $C4 = 10 \text{ nF}$ , 300 V + $R11$ to $R14 = 75 \Omega$ + +Termination circuit: 1 nF 3 kV + +Labels: a, b, c, d + +Reference bar + +Screen + +PE + +SPD + +Cable port + +Equipment port + +Generator return/Earth + +$R9 = 5 \Omega$ + +1.2/50-8/20 combination wave generator + +K.117(16)\_F04 + +Figure 4 – Impulse limiting voltage under common-mode surge conditions. The diagram shows a test circuit for measuring impulse limiting voltage. On the left, a 1.2/50-8/20 combination wave generator is connected to the SPD's cable port (terminals 1, 2, 3, 4, 5, 6, 7, 8) through a resistor R9 = 5 Ω. The generator's return/earth is connected to a reference bar (point 'a'). The SPD has an equipment port (terminals 1, 2, 3, 4, 5, 6, 7, 8) connected to a termination circuit. The termination circuit consists of eight resistors (R1 to R8 = 1 Ω) in series with capacitors (C1 to C4 = 10 nF, 300 V) and resistors (R11 to R14 = 75 Ω). The termination circuit is connected to a reference bar (point 'c') and a 1 nF 3 kV capacitor (C5) connected to ground (point 'd'). The SPD's screen is connected to the reference bar (point 'b'). + +Figure 4 – Impulse limiting voltage under common-mode surge conditions + +**Table 1 – Preferred values of common-mode impulse limiting voltage** + +| Generator charge voltage | Maximum impulse limiting voltage on any SPD equipment port terminal (excluding the screen connection) | +|---------------------------------|--------------------------------------------------------------------------------------------------------------| +| kV | kV | +| 2.5 | 1.0 | +| 6 | 1.5 | +| 12 | 2.0 | +| Manufacturer defined | Manufacturer defined | + +The recorded peak voltages shall not exceed the impulse limiting voltage corresponding to the selected generator charge voltage. After the surge testing, the 500 V insulation resistance values shall not be less than 2 M $\Omega$ . + +## **6.2 Differential-mode surge** + +The most critical factor for a twisted pair differential surge is the current waveform as the port termination is a low value resistance, usually below 5 $\Omega$ . Conversely, the most critical factor for a PoE power feed pair is peak voltage as the need is to protect some form of integrated circuit, which usually is rated at about 100 V. Common-mode surge operation of an SPD can generate differential-mode surges and these self-generated differential-mode surges at the SPD cable connection should not exceed the specified differential-mode surge voltage levels for a single twisted pair and power feed pairs. + +### **6.2.1 Single twisted pair** + +The purpose of this test is to measure the termination differential-mode surge levels of a single twisted pair. The test circuit is shown in Figure 5. In Figure 5 all four switches, SW(1-2) to SW(7-8), are single-pole change-over break before make ones. The switch contact arm is shown in red to clearly indicate the arm position. Figure 5 shows the test configuration for port terminal pair 1-2 with the generator output connected to terminal 1 via switch SW(1-2). The test configuration for a given terminal pair is with that terminal pair switch connecting the switched terminal to the generator series resistor R9, while all the other three terminal pair switches connect their terminals to the reference bar. + +To test this, set the generator charge voltage to the required level from Table 2 and surge the SPD while recording the selected SPD equipment port termination peak voltage and current. Record the termination peak voltage and current. Repeat this test with the generator voltage polarity reversed. Repeat this procedure until all the appropriate port terminals have been measured and their peak voltage and current values recorded. Finally, measure the d.c. insulation resistance for terminals 1 to 8 of the SPD cable port, as described in clause 7.1. + +![Figure 5 – Single twisted-pair differential-mode surge test circuit. The diagram shows a 1.2/50-8/20 generator connected to a cable port (1-8) through a switch (SW) and resistors R9 (10 Ω) and R10 (10 Ω). The cable port is connected to an equipment port (1-8) through an SPD. The equipment port is connected to a termination circuit containing resistors R1 to R8 (1 Ω), capacitors C1 to C4 (10 nF, 300 V), and resistors R11 to R14 (75 Ω). The termination circuit is connected to a reference bar (a, b, c, d) and a PE (Screen) connection. The diagram also includes a 'Differential voltage' measurement point and a 'Termination circuit' label with '1 nF 3 kV'.](af7916c89a458fdab6c3f443217388ae_img.jpg) + +Figure 5 – Single twisted-pair differential-mode surge test circuit. The diagram shows a 1.2/50-8/20 generator connected to a cable port (1-8) through a switch (SW) and resistors R9 (10 Ω) and R10 (10 Ω). The cable port is connected to an equipment port (1-8) through an SPD. The equipment port is connected to a termination circuit containing resistors R1 to R8 (1 Ω), capacitors C1 to C4 (10 nF, 300 V), and resistors R11 to R14 (75 Ω). The termination circuit is connected to a reference bar (a, b, c, d) and a PE (Screen) connection. The diagram also includes a 'Differential voltage' measurement point and a 'Termination circuit' label with '1 nF 3 kV'. + +**Figure 5 – Single twisted-pair differential-mode surge test circuit** + +**Table 2 – Preferred values of termination peak voltage and current** + +| Generator charge voltage
kV | Measured values for 1-2, 3-6, 4-5 and 7-8 | | +|--------------------------------|-------------------------------------------|-------------------------------| +| | Termination peak voltage
V | Termination peak current
A | +| 2.5 | 100 | 50 | +| 6 | 200 | 100 | +| 12 | 300 | 150 | +| Manufacturer defined | Manufacturer defined | Manufacturer defined | + +The recorded peak levels shall not exceed the termination peak values corresponding to the selected generator charge voltage. After the surge testing, the 500 V insulation resistance values shall not be less than 2 MΩ. + +### 6.2.2 PoE power feed pairs + +PoE power can be delivered in either mode A or mode B, or both modes (A + B). In powered equipment (PD) the power feed is extracted from the twisted pairs, sent to a multiphase diode bridge, decoupled and overvoltage protected before being applied to a d.c./d.c. converter. Power sourcing equipment (PSE) usually has some form of power regulator with overvoltage protection which feeds the power to the twisted pairs. The Figure 6 test circuit uses a powered equipment type termination as it works for both surge polarities and is often the equipment with the lowest surge resistibility. The components and their values correspond to the established components used in [b-IEEE 802.3] designs. Diodes D1 to D4 and D6 to D9 form polarity correction bridges that feed the avalanche breakdown diodes D5 and D10 and capacitors C1 and C2. Typical emulation components used are Schottky rectifier bridge diodes type B1100/B, avalanche breakdown diode type SMAJ58A and decoupling capacitor 100 nF, 100 V. + +In Figure 6, switch SW selects test mode A or test mode B. The peak surge voltage in these modes is measured at the SPD equipment port termination. + +To test this, set the generator charge voltage to the required level from Table 3, set switch SW for a mode and surge the SPD while measuring the SPD equipment port termination peak voltage for that mode. Record the termination peak voltage. Repeat this test with the generator voltage polarity reversed. Repeat this procedure for the other mode. Finally, measure the d.c. insulation resistance for terminals 1 to 8 of the SPD cable port, as described in clause 7.1. + +![Figure 6 – Power feed differential mode surge test circuit. The diagram shows a 1.2/50-8/20 Generator connected to a switch (SW) via resistors R9 and R10 (both 10 Ω). The switch selects between test mode A and test mode B. The SPD (Surge Protection Device) has a cable port with terminals 1, 2, 3, 4, 5, 6, 7, and 8, and an equipment port with terminals 1, 2, 3, 4, 5, 6, 7, and 8. The equipment port is connected to a PoE port termination box containing diodes D1 through D10, capacitors C1 and C2, and a reference bar. The generator return/earth is connected to a reference bar (a, b, c) which is also connected to the SPD screen and PE (Protective Earth).](4ee27dbf5ef12e7b58b0ef0937bc5a5e_img.jpg) + +Figure 6 – Power feed differential mode surge test circuit. The diagram shows a 1.2/50-8/20 Generator connected to a switch (SW) via resistors R9 and R10 (both 10 Ω). The switch selects between test mode A and test mode B. The SPD (Surge Protection Device) has a cable port with terminals 1, 2, 3, 4, 5, 6, 7, and 8, and an equipment port with terminals 1, 2, 3, 4, 5, 6, 7, and 8. The equipment port is connected to a PoE port termination box containing diodes D1 through D10, capacitors C1 and C2, and a reference bar. The generator return/earth is connected to a reference bar (a, b, c) which is also connected to the SPD screen and PE (Protective Earth). + +K.117(16)\_F06 + +##### Key + +SW = Double pole, two position selector switch + +R9, R10 = 10 Ω + +C1, C2 = 100 nF, 100 V + +D5, D10 = SMAJ58A or equivalent 400 W avalanche breakdown diodes + +D1 to D4, D6 to D9 = B1100/B Schottky rectifier diodes or equivalent 1 A, 100 V diodes + +**Figure 6 – Power feed differential mode surge test circuit** + +**Table 3 – Preferred mode A or mode B peak voltage** + +| Generator charge voltage
kV | Peak mode A or mode B
termination voltage
V | +|--------------------------------|---------------------------------------------------| +| 2.5 | 90 | +| 6 | 95 | +| 12 | 100 | +| Manufacturer defined | Manufacturer defined | + +The recorded peak voltages shall not exceed the peak mode A and peak mode B voltages corresponding to the selected generator charge voltage. After the surge testing, the 500 V insulation resistance values shall not be less than 2 MΩ. + +## 6.3 Common-mode to differential-mode surge conversion + +The purpose of this test is to measure the SPD common-mode to differential-mode surge conversion for the twisted-pair and power-feed situations of clause 6.2. + +In both Figure 7 and Figure 8 the generator output connects to each cable contact via a high value $40\ \Omega$ feed resistor to reduce the interactions. In Figure 7, the twisted pair is terminated in a high value resistance of $150\ \Omega$ to maximise the measured twisted-pair differential voltage. In Figure 8 the twisted pair termination is low in value ( $1\ \Omega+1\ \Omega$ ) as the measurement is being made pair to pair. + +![Figure 7 – Twisted-pair common-mode to differential mode voltage surge conversion test circuit. The diagram shows a 1.2/50-8/20 generator connected to a 'Generator current sharing network' containing resistors R1 through R8, each 40 Ω. These resistors connect to 'Cable port' terminals 1 through 8. These terminals are connected to 'Equipment port' terminals 1 through 8 of an SPD. The SPD has a 'Screen' and 'PE' connection to a 'Reference bar' at points 'a', 'b', and 'c'. The 'Generator return/Earth' is also connected to the reference bar. On the equipment side, twisted pairs are terminated in a 'Termination circuit' containing resistors R12, R36, R45, and R78, each 150 Ω. Vertical double-headed arrows between the equipment ports indicate the 'Twisted pair differential voltage' being measured.](7efae06af3af43ffe5d4b956a679cf54_img.jpg) + +The diagram illustrates the test circuit for twisted-pair common-mode to differential mode voltage surge conversion. A 1.2/50-8/20 generator is connected to a 'Generator current sharing network' which includes eight resistors, R1 through R8, each with a value of $40\ \Omega$ . These resistors are connected to 'Cable port' terminals 1 through 8. These terminals are then connected to 'Equipment port' terminals 1 through 8 of an SPD. The SPD has a 'Screen' and 'PE' connection to a 'Reference bar' at points 'a', 'b', and 'c'. The 'Generator return/Earth' is also connected to the reference bar. On the equipment side, twisted pairs are terminated in a 'Termination circuit' which includes resistors R12, R36, R45, and R78, each with a value of $150\ \Omega$ . Vertical double-headed arrows between the equipment ports indicate the 'Twisted pair differential voltage' being measured. + +Figure 7 – Twisted-pair common-mode to differential mode voltage surge conversion test circuit. The diagram shows a 1.2/50-8/20 generator connected to a 'Generator current sharing network' containing resistors R1 through R8, each 40 Ω. These resistors connect to 'Cable port' terminals 1 through 8. These terminals are connected to 'Equipment port' terminals 1 through 8 of an SPD. The SPD has a 'Screen' and 'PE' connection to a 'Reference bar' at points 'a', 'b', and 'c'. The 'Generator return/Earth' is also connected to the reference bar. On the equipment side, twisted pairs are terminated in a 'Termination circuit' containing resistors R12, R36, R45, and R78, each 150 Ω. Vertical double-headed arrows between the equipment ports indicate the 'Twisted pair differential voltage' being measured. + +Figure 7 – Twisted-pair common-mode to differential mode voltage surge conversion test circuit + +![Circuit diagram for Figure 8 showing a power feed pair common-mode to differential mode surge conversion test circuit. It includes a 1.2/50-8/20 Generator connected to a Generator current sharing network with resistors R1-R8 (40 Ω each). This is connected to the Cable port (1-8) of an SPD. The SPD's Equipment port (10-8) is connected to a Termination circuit with resistors R11-R18 (1 Ω each). The diagram also shows PoE differential voltage, Mode A and Mode B differential voltages, a PE reference bar, and a screen connection. The diagram is labeled K.117(16)_F08.](fa859e4e468bfb2710a94527f2c504af_img.jpg) + +Circuit diagram for Figure 8 showing a power feed pair common-mode to differential mode surge conversion test circuit. It includes a 1.2/50-8/20 Generator connected to a Generator current sharing network with resistors R1-R8 (40 Ω each). This is connected to the Cable port (1-8) of an SPD. The SPD's Equipment port (10-8) is connected to a Termination circuit with resistors R11-R18 (1 Ω each). The diagram also shows PoE differential voltage, Mode A and Mode B differential voltages, a PE reference bar, and a screen connection. The diagram is labeled K.117(16)\_F08. + +**Figure 8 – Power feed pair common-mode to differential mode surge conversion test circuit** + +For Figure 7, set the generator charge voltage to the level used in clause 6.2.1 and surge the SPD while measuring the SPD equipment port pair 1-2 termination peak voltage. Record the termination peak voltage. Repeat this test with the generator voltage polarity reversed. Repeat this procedure for the port pairs of 3-6, 4-5 and 7-8. Finally, measure the d.c. insulation resistance for terminals 1 to 8 of the SPD cable port, as described in clauses 7.1 and 6.2.2 from Table 3. + +For Figure 8, set the generator charge voltage to the level used in clause 6.2.2 and surge the SPD while measuring the SPD equipment port mode A peak voltage. Record the termination peak voltage. Repeat this test with the generator voltage polarity reversed. Repeat this procedure for the port mode B peak voltage. Finally, measure the d.c. insulation resistance for terminals 1 to 8 of the SPD cable port, as described in clause 7.1. + +**Table 4 – Preferred maximum values common-mode to differential mode surge voltage** + +| Generator charge voltage
kV | Peak twisted-pair
differential termination
voltage
V | Peak mode A or mode B
differential termination
voltage
V | +|--------------------------------|---------------------------------------------------------------|-------------------------------------------------------------------| +| 2.5 | 100 | 90 | +| 6 | 200 | 95 | +| 12 | 300 | 100 | +| Manufacturer defined | Manufacturer defined | Manufacturer defined | + +The recorded peak voltages shall not exceed the peak differential voltage values corresponding to the selected generator charge voltage. After the surge testing, the 500 V insulation resistance values shall not be less than 2 MΩ. + +## 6.4 Surge durability (optional) + +This test verifies the surge durability of the SPD. + +For each of the selected test levels and configurations of clauses 6.1, 6.2.1 and 6.2.2 apply 50 surges in one polarity followed by 50 surges in the opposite polarity. Finally, measure the d.c. insulation resistance for terminals 1 to 8 as appropriate of the SPD cable port, as described in clause 7.1. + +NOTE – Applying the surges first in one polarity, then in the opposite polarity maximises the electrode erosion of Figure 2 type technologies; see [b-ITU-T K.99]. + +After the surge durability testing, the SPD shall be tested as described in clauses 6.1, 6.2.1 and 6.2.2 at the selected surge levels. The SPD shall still comply with the requirements of these three tests. + +## 6.5 Cable screen terminal + +This test verifies the bonding of the cable port screen terminal to protective earth (PE) terminal, the equipment port screen terminal to PE terminal and the cable port screen terminal to the equipment port screen terminal. In the test circuit Figure 9, these test configurations are switch SW positions 1, 2 and 3. SPDs using the Figure 3 type protection may not have a PE terminal. + +To test this, set the generator charge voltage to the required level from Table 5, set switch SW for the appropriate test configuration and surge the SPD while measuring the SPD screen voltage of that configuration. Record the measured peak voltage. Repeat this test with the generator voltage polarity reversed. Repeat this procedure for the other appropriate configurations. Finally, measure the d.c. insulation resistance for terminals 1 to 8 of the SPD cable port, as described in clause 7.1. + +![Circuit diagram for screen bonding test (Figure 9).](43837b056625d3d6ce615e4c02f163bb_img.jpg) + +The diagram illustrates the test circuit for screen bonding. On the left, a '1.2/50-8/20 Generator' is shown. Its output is connected to a resistor labeled 'R9 = 5Ω'. This resistor is connected to a 'Double pole, three position selector switch' (SW). The switch has three positions labeled 1, 2, and 3. Position 1 connects the generator circuit to the 'Cable port' terminals (1, 2, 3, 6, 4, 5, 7, 8) of the SPD. Position 2 connects it to the 'Equipment port' terminals (1, 2, 3, 6, 4, 5, 7, 8). Position 3 connects it to the 'Screen' terminal of the SPD. The 'Generator return/Earth' is connected to a 'Reference bar'. The 'PE' (Protective Earth) terminal of the SPD is also connected to this 'Reference bar'. The 'Equipment port' is connected to a 'Reference bar' as well. The diagram is labeled 'b' and 'K.117(16)\_F09'. + +Key +SW = Double pole, three position selector switch      R9 = 5Ω + +Circuit diagram for screen bonding test (Figure 9). + +**Figure 9 – Screen bonding test** + +**Table 5 – Preferred maximum values of screen surge voltage based on [b-IEC 60603-7-7] screen contact resistance limits** + +| Generator charge voltage
kV | Maximum screen to PE voltage,
Figure 9 SW positions 1 and 2
V | Maximum screen to screen voltage,
Figure 9 SW position 3
V | +|--------------------------------|---------------------------------------------------------------------|------------------------------------------------------------------| +| 2.5 | 40 | 80 | +| 6 | 90 | 180 | +| 12 | 180 | 360 | +| Manufacturer defined | Manufacturer defined | Manufacturer defined | + +# 7 DC tests + +## 7.1 Insulation resistance + +Insulation resistance (IR) meters can produce voltages of up to 1 kV d.c. or more. To avoid possible electric shock or personal injury, the safety guidelines issued by the IR meter manufacturer should be followed. + +Figure 10 shows the test circuit to measure the insulation resistance of an SPD with a PE terminal or screen terminals, or both connections (protection function corresponding to Figure 2). The insulation resistance is measured between each twisted pair cable port contacts and the PE/screen terminals. [b-IEEE 802.3] requires that "the isolation resistance measured at 500 V d.c. shall be at least 2 M $\Omega$ ". + +![Figure 10: Test circuit to measure the insulation resistance of an SPD with a PE terminal or screen terminals, or both. The diagram shows an SPD with 8 cable ports (1-8) and 8 equipment ports (10-17). A four-position selector switch (SW) is connected to an IR meter (Ω) and a DC voltage source. The switch can connect the IR meter to the cable ports (positions 1.2, 3.6, 4.5, 7.8) or to the PE/screen terminals. The PE and Screen terminals are connected to a reference bar. The diagram is labeled 'b K.117(16)_F10'.](8592a32c2fdf17c1e562f0ba6b7e8e1a_img.jpg) + +Key +SW = Four position selector switch    Ω = IR meter with defined d.c. bias + +Figure 10: Test circuit to measure the insulation resistance of an SPD with a PE terminal or screen terminals, or both. The diagram shows an SPD with 8 cable ports (1-8) and 8 equipment ports (10-17). A four-position selector switch (SW) is connected to an IR meter (Ω) and a DC voltage source. The switch can connect the IR meter to the cable ports (positions 1.2, 3.6, 4.5, 7.8) or to the PE/screen terminals. The PE and Screen terminals are connected to a reference bar. The diagram is labeled 'b K.117(16)\_F10'. + +**Figure 10 – Test circuit to measure the insulation resistance of an SPD with a PE terminal or screen terminals, or both** + +Figure 11 shows the test circuit to measure the insulation resistance of an SPD without a PE terminal (protection function corresponding to Figure 3). The insulation resistance is measured between each twisted pair cable port contacts and the equipment port twisted pair contacts. + +![Figure 11: Test circuit to measure the insulation resistance of an isolating transformer SPD without a PE terminal. The diagram shows an SPD with 'Cable port' terminals 1, 2, 3, 4, 5, 6, 7, 8 and 'Equipment port' terminals 10, 20, 30, 40, 50, 60, 70, 80. A four-position selector switch (SW) is connected to an IR meter (Ω) with defined d.c. bias. The switch has positions for 1.2, 3.6, 7.8, and 4.5. The switch is connected to the cable port terminals. The equipment port terminals are connected to a reference bar. The screen of the SPD is also connected to the reference bar. The reference bar is connected to the IR meter. The diagram is labeled K.117(16)_F11. A key indicates SW = Four position selector switch and Ω = IR meter with defined d.c. bias.](7f25db95ce3916c0e09803b861a2f7bc_img.jpg) + +Figure 11: Test circuit to measure the insulation resistance of an isolating transformer SPD without a PE terminal. The diagram shows an SPD with 'Cable port' terminals 1, 2, 3, 4, 5, 6, 7, 8 and 'Equipment port' terminals 10, 20, 30, 40, 50, 60, 70, 80. A four-position selector switch (SW) is connected to an IR meter (Ω) with defined d.c. bias. The switch has positions for 1.2, 3.6, 7.8, and 4.5. The switch is connected to the cable port terminals. The equipment port terminals are connected to a reference bar. The screen of the SPD is also connected to the reference bar. The reference bar is connected to the IR meter. The diagram is labeled K.117(16)\_F11. A key indicates SW = Four position selector switch and Ω = IR meter with defined d.c. bias. + +**Figure 11 – Test circuit to measure the insulation resistance of an isolating transformer SPD without a PE terminal** + +This test measures the resistance of the insulation at a defined d.c. voltage. The insulation resistance meter shall be set for a d.c. test voltage of 500 V. The test voltage shall be applied for at least 60 s before the insulation resistance value is taken. The tested SPD must not be modified in any way for this test, for example removing any internal components. + +To test this, set switch SW, to select terminals 1, 2. Measure and record the 500 V insulation resistance value. Repeat this procedure with terminals 3, 6 selected, then for terminals 4, 5 selected and finally for terminals 7, 8 selected. + +The measured insulation resistance values shall be 2 M $\Omega$ or more, measured at 500 V d.c. + +## 7.2 DC voltage drop + +An Ethernet SPD intended for PoE will be able to transfer d.c. power in mode A, mode B or both (see clause 6.2.1). It is important that the SPD does not cause a significant power loss and the d.c. voltage drop test verifies the SPD power loss is less than the typical equipment Ethernet PoE transformer. + +The test circuit of Figure 12 passes 0.5 A through all the input/output contacts. The individual measured voltages $V_{12}$ , $V_{36}$ , $V_{45}$ and $V_{78}$ shall not exceed 0.5 V. This will guarantee the total d.c. power feed mode A or B series resistance of the SPD will not exceed 0.5 $\Omega$ . + +NOTE – This test approach cannot be used for SPDs that isolate the cable side PoE feed from the equipment side PoE feed by means of a d.c./d.c. converter. + +![Figure 12 – Test circuit to measure the PoE SPD d.c. input/output voltage drop. The diagram shows a PoE SPD device with 'Cable port' terminals 1, 2, 3, 4, 5, 6, 7, 8 and 'Equipment port' terminals 10, 20, 30, 40, 50, 60, 70, 80. A 0.5 A current source is connected between the Cable port terminals. Voltage drops are indicated: V12 between terminals 1 and 2, V36 between 3 and 6, V45 between 4 and 5, and V78 between 7 and 8. The SPD also has 'Screen' and 'PE' terminals at the bottom. The diagram is labeled K.117(16)_F12.](b6671cfafda3820aafe9a24fa7a4d8c7_img.jpg) + +Figure 12 – Test circuit to measure the PoE SPD d.c. input/output voltage drop. The diagram shows a PoE SPD device with 'Cable port' terminals 1, 2, 3, 4, 5, 6, 7, 8 and 'Equipment port' terminals 10, 20, 30, 40, 50, 60, 70, 80. A 0.5 A current source is connected between the Cable port terminals. Voltage drops are indicated: V12 between terminals 1 and 2, V36 between 3 and 6, V45 between 4 and 5, and V78 between 7 and 8. The SPD also has 'Screen' and 'PE' terminals at the bottom. The diagram is labeled K.117(16)\_F12. + +**Figure 12 – Test circuit to measure the PoE SPD d.c. input/output voltage drop** + +# **8 Identification** + +## **8.1 Marking** + +Legible and permanent marking shall be applied to the SPD, as necessary, to ensure that the user can determine the following information by inspection: + +- manufacturer +- year of manufacture +- device number or code +- port designation (cable or equipment) if the SPD requires specific installation. + +If requested and agreed, the customer's identification should be marked on each device. + +## **8.2 Documentation** + +Documents shall be provided to the user so that from the information in clause 8.1 the user can determine the following additional information: + +- appropriate device parameters as set out in this Recommendation +- component mounting requirements and processes. + +# **9 Ordering information** + +The following information should be supplied by the user: + +- drawing giving all dimensions, finishes and termination details +- type or model +- quantity +- quality assurance requirements. + +## Bibliography + +- [b-ITU-T K.28] Recommendation ITU-T K.28 (2012), *Parameters of thyristor-based surge protective devices for the protection of telecommunication installations.* +- [b-ITU-T K.82] Recommendation ITU-T K.82 (2010), *Characteristics and ratings of solid-state, self-restoring overcurrent protectors for the protection of telecommunications installations.* +- [b-ITU-T K.96] Recommendation ITU-T K.96 (2014), *Surge protective components: Overview of surge mitigation functions and technologies.* +- [b-ITU-T K.99] Recommendation ITU-T K.99 (2014), *Surge protective component application guide – Gas discharge tubes.* +- [b-IEC 14776-153] ISO/IEC 14776-153:2015, *Information technology – Small computer system interface (SCSI) – Part 153: Serial attached SCSI – 2.1 (SAS-2.1).* +- [b-IEC 60050-131] IEC 60050-131:2002, *International Electrotechnical Vocabulary – Part 131: Circuit theory.* +- [b-IEC 60050-161] IEC 60050-161:1990, *International Electrotechnical Vocabulary. Chapter 161: Electromagnetic compatibility.* +- [b-IEC 60050-212] IEC 60050-212:2010, *International Electrotechnical Vocabulary – Part 212: Electrical insulating solids, liquids and gases.* +- [b-IEC 60065] IEC 60065:2014, *Audio, video and similar electronic apparatus – Safety requirements.* +- [b-IEC 60601-2-1] IEC 60601-2-1:2009, *Medical electrical equipment – Part 2-1: Particular requirements for the basic safety and essential performance of electron accelerators in the range 1 MeV to 50 MeV.* +- [b-IEC 60603-7-7] IEC 60603-7-7:2010, *Connectors for electronic equipment – Part 7-7: Detail specification for 8-way, shielded, free and fixed connectors for data transmission with frequencies up to 600 MHz.* +- [b-IEC TR 60664-2-1] IEC TR 60664-2-1 (2011), *Insulation coordination for equipment within low voltage systems – Part 2-1: Application guide – Explanation of the application of the IEC 60664 series, dimensioning examples and dielectric testing.* +- [b-IEC 61643-341] IEC 61643-341:2001, *Components for low-voltage surge protective devices – Part 341: Specification for thyristor surge suppressors (TSS).* +- [b-IEEE 802.3] 802.3-2015, *IEEE Standard for Ethernet.* + + + + + +## **SERIES OF ITU-T RECOMMENDATIONS** + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.118-201612-I_PDF-E/raw.md b/marked/K/T-REC-K.118-201612-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..66fd1492a7f97f652499c357d89f7b5df2e62c61 --- /dev/null +++ b/marked/K/T-REC-K.118-201612-I_PDF-E/raw.md @@ -0,0 +1,421 @@ + + +International Telecommunication Union + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.118** + +(12/2016) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Requirements for lightning protection of fibre to +the distribution point equipment** + +Recommendation ITU-T K.118 + +![ITU logo](6ed175c791b5e156d9c98a8dbcc3318c_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a red lightning bolt striking it, symbolizing telecommunications. The text "ITU" is prominently displayed in blue, with "International Telecommunication Union" written in smaller blue text to the right. + +ITU logo + + + +# Recommendation ITU-T K.118 + +# Requirements for lightning protection of fibre to the distribution point equipment + +## Summary + +Recommendation ITU-T G.9701 specifies a gigabit broadband access technology that exploits the existing infrastructure of wire pairs that were originally deployed for plain old telephone service (POTS) services. Equipment implementing this Recommendation can be deployed from fibre to the distribution point (FTTdp) located very near the customers' premises. + +Recommendation ITU-T K.118 contains the necessary information to enable the protection of a distribution point (DP) node in the access network and the associated equipment in the customers' premises. It includes information on the resistibility requirements of the equipment, the rating of the lightning protection, when the installation of protection is necessary and on how to install this protection. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.118 | 2016-12-14 | 5 | 11.1002/1000/13134 | + +## Keywords + +EPR, GDT, lightning protection, MOVs, MSPDs, power contact and SPDs. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2017 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-------------------------------------------------------------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 2 | +| 3.1 Terms defined elsewhere ..... | 2 | +| 3.2 Terms defined in this Recommendation..... | 2 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 3 | +| 6 Elements of protection..... | 3 | +| 6.1 Correct classification and use of ports..... | 4 | +| 6.2 Equipment design considerations ..... | 4 | +| 6.3 Equipment resistibility..... | 6 | +| 6.4 Primary protection and MSPDs..... | 6 | +| 6.5 Requirements for earthing and bonding ..... | 7 | +| 6.6 Risk assessment ..... | 7 | +| 6.7 Responsibility ..... | 8 | +| 6.8 A.C. earth potential rise (EPR)..... | 8 | +| Appendix I – Level of protection..... | 9 | +| I.1 Protection against surges induced into external cables ..... | 9 | +| I.2 Protection against direct strikes to the power or telecommunications
cables or lines more than 100 m away from the DPU ..... | 9 | +| I.3 Protection against direct strikes..... | 9 | +| Bibliography..... | 10 | + +# **Introduction** + +Fibre to the distribution point (FTTdp) supports one or more high-speed copper drops into customer premises and uses a gigabit (or faster) fibre link to backhaul user data to a high order node (HON). A key aspect of the new node type is the ability for it to be reverse power fed from one or more copper drop pairs. To reverse power feed (RPF), there needs to be power supply functionality at the customer's premises. To this end a new node type, the distribution point unit (DPU), is defined. This node is typically positioned at the distribution point (DP). + +To maintain the reliability of the network it is necessary to ensure that this equipment has the required level of resistibility and that the necessary lightning protection is installed when needed. + +# Recommendation ITU-T K.118 + +## Requirements for lightning protection of fibre to the distribution point (FTTdp) equipment + +# 1 Scope + +This Recommendation applies to the equipment installed at the distribution point (DP) node and the associated equipment installed at the customers' premises. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.12] Recommendation ITU-T K.12 (2010), *Characteristics of gas discharge tubes for the protection of telecommunications installations.* +- [ITU-T K.21] Recommendation ITU-T K.21 (2016), *Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents.* +- [ITU-T K.35] Recommendation ITU-T K.35 (1996), *Bonding configurations and earthing at remote electronic sites.* +- [ITU-T K.44] Recommendation ITU-T K.44 (2016), *Resistibility tests for telecommunication equipment exposed to overvoltages and overcurrents – Basic Recommendation.* +- [ITU-T K.45] Recommendation ITU-T K.45 (2016), *Resistibility of telecommunication equipment installed in the access and trunk networks to overvoltages and overcurrents.* +- [ITU-T K.65] Recommendation ITU-T K.65 (2011), *Overvoltage and overcurrent requirements for termination modules with contacts for test ports or surge protective devices.* +- [ITU-T K.66] Recommendation ITU-T K.66 (2011), *Protection of customer premises from overvoltages.* +- [ITU-T K.75] Recommendation ITU-T K.75 (2016), *Classification of interface for application of standards on resistibility and safety of telecommunication equipment.* +- [ITU-T K.85] Recommendation ITU-T K.85 (2011), *Requirements for the mitigation of lightning effects on home networks installed in customer premises.* +- [ITU-T K.98] Recommendation ITU-T K.98 (2014), *Overvoltage protection guide for telecommunication equipment installed in customer premises.* +- [ITU-T K.108] Recommendation ITU-T K.108 (2015), *Joint use of poles by telecommunication and solidly earthed power lines.* +- [ITU-T K.109] Recommendation ITU-T K.109 (2015), *Installation of telecommunication equipment on utility poles.* +- [IEC 60950-1] IEC 60950-1:2005+AMD1:2009+AMD2:2013 CSV, *Information technology equipment – Safety – Part 1: General requirements.* + +- [IEC 61643-311] IEC 61643-331:2013, *Components for low-voltage surge protective devices – Part 311: Performance requirements and test circuits for gas discharge tubes (GDT)*. +- [IEC 61643-331] IEC 61643-331:2003, *Components for low-voltage surge protective devices – Part 331: Specification for metal oxide varistors (MOV)*. +- [IEC 62305-2] IEC 62305-2 Ed. 2.0 (2010), *Protection against lightning – Part 2: Risk management*. +- [IEC 62368-1] IEC 62368-1 Ed. 2.0 (2014), *Audio/video, information and communication technology equipment – Part 1: Safety requirements*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 high current carrying protection components** [ITU-T K.44]: A high current carrying protection component is an SPD which, when activated by the surge, conducts/diverts the majority of the surge away from the circuit it is protecting. High current carrying protection components are mainly used as primary protection components, but in some cases may be integrated into the equipment as inherent protection. + +**3.1.2 inherent protection** [ITU-T K.44]: Inherent protection is protection that is provided within the equipment either by virtue of its intrinsic characteristics, by specific design, or by suitable protection components. + +**3.1.3 primary protection** [ITU-T K.44]: Means by which the majority of the surge stress is prevented from propagating beyond a designated location (preferably the building entrance point). + +**3.1.4 spark-overvoltage** [ITU-T K.12]: The voltage which causes spark-over when applied across the terminals of a gas discharge tube. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following term: + +**3.2.1 thermal protection:** integral switch function of a surge protective component (SPC) that operates when the component temperature exceeds a pre-set value. + +NOTE 1 – A thermally protected gas discharge tube (GDT) has a normally open thermal switch connected in parallel with the electrodes, which shorts out the GDT when the component temperature exceeds a pre-set value. + +NOTE 2 – A thermally protected metal oxide varistor (MOV) has a normally closed thermal switch connected in series with MOV element, which disconnects the MOV when the component temperature exceeds a pre-set value. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|-------------------------| +| a.c. | alternating current | +| d.c. | direct current | +| DP | Distribution Point | +| DPU | Distribution Point Unit | +| EPR | Earth Potential Rise | + +| | | +|-------|---------------------------------------| +| ES1 | Electrical Energy Source class 1 | +| ES2 | Electrical Energy Source class 2 | +| FTTdp | Fibre To The distribution point | +| GDT | Gas Discharge Tube | +| HON | High Order Node | +| MEB | Main Electrical Board | +| MOV | Metal Oxide Varistor | +| MSPD | Multi-service Surge Protective Device | +| PE | Protective Earth | +| RPF | Reverse Power Feeding | +| SELV | Safety Extra Low Voltage | +| SPC | Surge Protective Component | +| SPD | Surge Protective Device | +| VoIP | Voice over Internet Protocol | + +# 5 Conventions + +None. + +# 6 Elements of protection + +Fibre to the distribution point (FTTdp) supports one or more high-speed copper drops into customer premises and uses a gigabit (or faster) fibre link to backhaul user data to a high order node (HON). A key aspect of the new node type is the ability for it to be reverse power fed from one or more copper drop pairs. To reverse power feed (RPF), there needs to be power supply functionality at the customer premises. To this end a new node type, the distribution point unit (DPU), is defined. This node is typically positioned at the distribution point (DP). + +![Diagram of Fibre to the distribution point (FTTdp) showing two customer premises connected to a central FTTdp equipment. Each customer premise contains a Modem and an RPF. The Modem is connected to the RPF, and the RPF is connected to the FTTdp equipment. The FTTdp equipment is also connected to an existing copper cable from the exchange node and an optic fibre. The diagram is labeled K.118(16)_F01.](a5ee5c23b6dc52ec1d724b76d5a5f58f_img.jpg) + +The diagram illustrates the FTTdp architecture. On the left, two 'Customer premises' are shown, each containing a 'Modem' and an 'RPF'. The Modem is connected to the RPF, and the RPF is connected to the 'FTTdp equipment' on the right. The FTTdp equipment is connected to an 'Existing copper to exchange node' and an 'Optic fibre'. A dashed line connects the two customer premises, indicating they are separate units. The diagram is labeled 'K.118(16)\_F01'. + +Diagram of Fibre to the distribution point (FTTdp) showing two customer premises connected to a central FTTdp equipment. Each customer premise contains a Modem and an RPF. The Modem is connected to the RPF, and the RPF is connected to the FTTdp equipment. The FTTdp equipment is also connected to an existing copper cable from the exchange node and an optic fibre. The diagram is labeled K.118(16)\_F01. + +In some implementations the FTTdp equipment may be connected to the existing copper cable from the exchange node until all customers are converted to VoIP. + +**Figure 1 – Fibre to the distribution point (FTTdp)** + +There are many different methods of supplying the RPF to the FTTdp equipment at the DP. In some applications the modem signal will share the copper pair and in other applications separate pairs will be used. These options are described in [b-ETSI TS 101 548]. + +To ensure that adequate lightning protection is installed, or can be installed, it is necessary to consider a number of issues. These are: + +- 1 correct classification and use of ports +- 2 equipment design considerations +- 3 equipment resistibility +- 4 primary protection +- 5 requirements for earthing and bonding +- 6 risk assessment +- 7 responsibility +- 8 A.C. earth potential rise (EPR). + +## 6.1 Correct classification and use of ports + +Correct classification and use of ports: It is necessary that the equipment ports have been correctly classified, designed and used in accordance with [ITU-T K.75]. + +For the RPF equipment installed in the customer premises both the mains and the power feed ports need to be "external ports". + +For the DP equipment all ports need to be "external ports". + +## 6.2 Equipment design considerations + +Where lightning protection above the inherent resistibility level of 1.5 kV is required, there are two options: + +- Add primary protection outside the equipment when a risk assessment indicates that protection should be installed. + +- Design the equipment with integral high current carrying protection components (e.g., gas discharge tubes (GDTs)) as part of the inherent protection. Typically, this is only implemented for access network equipment. + +In both cases the protection could be used as bypass protection or the protection could be earthed. Bypass and earthed protection is shown pictorially in Figure 2. + +![Figure 2 – Pictorial illustration of bypass and earthed protection. The diagram shows two configurations for FTTdp equipment protection. The top configuration, labeled 'Bypass protection', shows the equipment connected to two GDTs (Cust 1 GDT and Cust 2 GDT) which are then connected to a common bypass line. The bottom configuration, labeled 'Earthed protection', shows the equipment connected to two GDTs (Cust 1 GDT and Cust 2 GDT) which are then connected to a common 'Network earth' point. Both diagrams include a 'Fibre' input and output, and lightning strike symbols on the input lines.](e9314c83043183351ed74908e9bf2f90_img.jpg) + +The diagram consists of two parts. The upper part illustrates 'Bypass protection'. It shows a central box labeled 'FTTdp equipment'. To its left, two lines enter from 'Cust 1 GDT', and to its right, two lines exit to 'Cust 2 GDT'. Red lightning bolts indicate surges on the input lines. A red line bypasses the equipment, connecting the GDTs directly. A blue line labeled 'Fibre' also enters and exits the equipment. The lower part illustrates 'Earthed protection'. It is similar to the upper part but instead of a bypass line, the GDTs and the equipment are connected to a common point labeled 'Network earth', which is connected to a ground symbol labeled 'Earthed protection'. The reference code 'K.118(16)\_F02' is in the bottom right. + +Figure 2 – Pictorial illustration of bypass and earthed protection. The diagram shows two configurations for FTTdp equipment protection. The top configuration, labeled 'Bypass protection', shows the equipment connected to two GDTs (Cust 1 GDT and Cust 2 GDT) which are then connected to a common bypass line. The bottom configuration, labeled 'Earthed protection', shows the equipment connected to two GDTs (Cust 1 GDT and Cust 2 GDT) which are then connected to a common 'Network earth' point. Both diagrams include a 'Fibre' input and output, and lightning strike symbols on the input lines. + +**Figure 2 – Pictorial illustration of bypass and earthed protection** + +### 6.2.1 Floating equipment + +This is equipment that does not require a protective earth (PE) and it is powered from an SELV, ES1 or ES2 circuit, or has a double insulated power supply. + +If the DPU will not be earthed it is a good idea to ensure that a flashover to earth is unlikely. A figure of 20 kV of isolation is probably a good figure to achieve. While it is possible for a telecommunications cable to conduct 100 kV surges, joints will break down at lower voltages. At the breakdown point of the joint an EPR will occur and the voltage on the cable can still be more than the breakdown voltage of the joint. The more joints that break down the lower the cable voltage will be. Further information on the surge voltage in a cable is provided in [ITU-T K.98]. + +[ITU-T K.109] has additional requirements for installations on power poles. + +### 6.2.2 Earthed equipment + +This equipment requires a PE connection. + +[ITU-T K.109] has additional requirements for installations on power poles. + +### 6.2.3 Equipment with integral high current carrying protection components + +This is equipment with integral high current carrying protection components. The "enhanced requirement" in [ITU-T K.21] and [ITU-T K.45] requires that the current carrying capacity of the printed circuit tracks needs to be 5 kA 8/20 $\mu\text{s}$ per conductor and 30 kA 8/20 $\mu\text{s}$ for the conductors carrying the sum of the single conductor currents. + +NOTE – Printed circuit tracks, particularly the track conducting the sum of the currents, will need to be thicker and wider than normal tracks. This ensures compatibility with good quality filled cable connectors (grease or gel filled) which can safely conduct 5 kA 8/20 $\mu$ s currents. + +## **6.3 Equipment resistibility** + +### **6.3.1 Network equipment installed in the network** + +For **network equipment installed in the network** the requirements should be as recommended in [ITU-T K.45]. The "Enhanced" test levels are suggested to ensure reliable equipment, particularly for equipment which contains high current carrying protection components within the equipment to eliminate the need for primary protection. + +### **6.3.2 Network equipment installed in customer premises** + +For **network equipment installed in customer premises** the requirements should be as recommended in [ITU-T K.21]. The "Enhanced" test levels are suggested to ensure reliable equipment. + +NOTE – For "floating equipment", with no connection to PE, the line to earth resistibility requirement is 6 kV for the "Enhanced" test level and this ensures a far more robust product. + +## **6.4 Primary protection and MSPDs** + +Refer to clause 6.6 on performing a risk assessment to determine when primary protection is necessary. Refer to clause 6.7 regarding the responsibility for installing lighting protection. + +#### **6.4.1 Requirements of the SPDs** + +#### **6.4.1.1 Multi-service surge protective devices (MSPDs)** + +MSPDs shall comply with [IEC 60950-1] or [IEC 62368-1]. The protection components shall comply with [IEC 61643-331] for MOVs and [IEC 61643-311] for GDTs. Ideally, the MOVs should have a minimum of a 5kA rating and the GDTs should have a minimum of a 5 kA rating per side, (i.e., 10 kA in the centre electrode for a 3 electrode type). + +#### **6.4.1.2 GDTs at the DPU** + +This applies to GDTs within the equipment or those installed in a protection frame. The GDTs should have a minimum of a 5 kA rating per side (i.e., 10 kA in the centre electrode for a 3 electrode type). The spark-over voltage will be as agreed by the equipment manufacturer and the network operator. Guidance is provided in [ITU-T K.12]. Refer to clause 6.4.1.5 for power contact and fire considerations. + +#### **6.4.1.3 GDTs at customer premises** + +The GDTs should have a minimum of a 5 kA rating per side, (i.e., 10 kA in the centre electrode for a 3 electrode type). The spark-over voltage will be as agreed by the equipment manufacturer and the network operator. Guidance is provided in [ITU-T K.12]. National regulations of the country may have specific requirements. Refer to clause 6.4.1.5 for power contact and fire considerations. + +#### **6.4.1.4 Mains SPDs at customer premises** + +Ideally, the SPD should have a minimum of a 40 kA 8/20 $\mu$ s rating. In extreme situations, e.g., long rural power lines, an SPD with a 100 kA 8/20 $\mu$ s rating should be considered. + +#### **6.4.1.5 Fire consideration** + +Consideration should be given to the possibility of a power contact to the telecommunications line causing the GDT to overheat and resulting in a fire. A fire can be prevented by selecting the voltage limiter threshold voltage to be above the mains voltage or by the use of thermal protection to prevent the GDT from overheating. + +Where the GDT is an integral part of the equipment the requirements are contained in [ITU-T K.21] and [ITU-T K.45] as applicable and in [IEC 62368-1]. Where the GDT is installed in a protection frame the requirements are given in [ITU-T K.65]. + +#### **6.4.2 Installation** + +#### **6.4.2.1 DPU** + +When needed, GDTs could be installed outside the equipment or the equivalent of primary protection included in the equipment design as inherent protection. The GDT requirements are provided in [ITU-T K.12]. The protection holder requirements are provided in [ITU-T K.65]. + +NOTE – When the equivalent of primary protection is included in the equipment design as inherent protection, primary protection is not required. + +#### **6.4.2.2 Customer premises** + +Overvoltage protection, when required, should be installed according to [ITU-T K.66]. This includes the use of both MSPDs and primary protectors for both the mains and telecommunications services. + +An MSPD should be the first level of protection for equipment installed in the customers' premises to protect the RPF equipment. The requirements for installing MSPDs are provided in [ITU-T K.66]. + +To prevent possible problems both the RPF equipment, the modem and any nearby equipment such as a computer or mains powered telephone plugged into the modem, need to be powered from this MSPD. Ideally, if mains powered telephones are used remotely from the modem the "internal" port of the modem needs to be protected to prevent both damage to the modem and possible damage to the RPF equipment. This is described in [ITU-T K.66]. However, as an MSPD with the necessary internal port protection does not exist, this protection cannot be easily provided. Responsibility for the decision to install, or when to install, an MSPD needs to be allocated. + +In lightning-prone areas primary protection may also need to be installed. This would include an SPD in the main electrical board (MEB) and GDTs on the cable from the DP. This is to protect the MSPD. + +## **6.5 Requirements for earthing and bonding** + +For customer premises the earthing and bonding practices should comply with [ITU-T K.66]. Earthing is the connection of the earth bar to earth, usually via an installed earth electrode. Bonding is the interconnection of earth electrodes and metallic parts to minimise potential differences. + +For the DPU the earthing and bonding practices should comply with [ITU-T K.35] if earthing is provided. The value of the resistance of the earthing electrode depends on its function. If required for functional reasons a single earth electrode is all that is required. If the earth is required to protect against a direct strike to the pole a 10 Ω earth is a nominal requirement. As this may be difficult to achieve, a higher value may need to be accepted. [ITU-T K.109] has additional requirements for installations on power poles. + +## **6.6 Risk assessment** + +To determine the risk of lightning damage for different installations [IEC 62305-2] can be used to perform a risk assessment. This would determine when MSPDs and primary protection are required. Examples of such risk assessments are provided in [ITU-T K.85]. + +### **6.6.1 DPU** + +If the DPU equipment has integral high current carrying protection components (e.g., GDTs) as part of the inherent protection, the equivalent of primary protection is effectively always provided. + +If primary protection is added to a protection frame when necessary, either the equipment provider, installer or network operator has to decide when primary protection is required and take the necessary steps to ensure that it is installed. + +### **6.6.2 Customer premises** + +At the customer's premises, it is necessary to decide when to: + +- 1 install an MSPD to protect the RPF equipment and associated equipment; +- 2 install primary protection on both the telecommunications and power services. Note, some services may already have an SPD for the power service to protect computer-controlled equipment such as washing machines, etc. + +## **6.7 Responsibility** + +To ensure that the required level of protection is provided it is necessary that the parties involved agree on the breakdown of responsibility. Proposals for the sharing of this responsibility are provided in [ITU-T K.66] and [ITU-T K.85]. + +## **6.8 A.C. earth potential rise (EPR)** + +Avoiding an a.c. EPR in the network is outside the scope of this document but it is an issue which needs consideration when installing DPUs. [ITU-T K.109] has requirements for installations on power poles. + +# Appendix I + +## Level of protection + +(This appendix does not form an integral part of this Recommendation.) + +Three levels of protection can nominally be provided. + +### **I.1 Protection against surges induced into external cables** + +The equipment inherent resistibly level of 1.5 kV is meant to provide protection against approximately 95% of induced surges. However, this is not an indication of how often damage may occur. [IEC 62305-2] can be used to determine the frequency of damage. [IEC 62305-2] nominally calculates loss but without understanding the implications that it can result in an incorrect conclusion. + +### **I.2 Protection against direct strikes to the power or telecommunications cables or lines more than 100 m away from the DPU** + +The installation of an MSPD at customers' premises will protect the equipment in the majority of cases. The use of MSPDs in suburban areas would ensure that overvoltage damage is kept to a low level. The installation of primary protection in the main electrical switchboard and in the telecommunications termination box will enhance this protection particularly against surges entering on the mains conductors. Primary protection is probably unnecessary for most installations except in known lightning-prone areas. + +The use of primary protection at the DPU or the use of a DPU with inherent protection equivalent to primary protection will protect the equipment in the majority of cases. + +Both of the above statements are based on the data in [ITU-T K.98]. + +### **I.3 Protection against direct strikes** + +This would mean protection against direct strikes to the houses, to the pole and even the cable in high lightning-prone areas. It would require direct strike protection of the building and a 10 ohm earth for each structure. Protection to this level would incur significant expense and is not practical. + +# Bibliography + +- [b-ITU-T G.9701] Recommendation ITU-T G.9701 (2014), *Fast access to subscriber terminals (G.fast) – Physical layer specification.* +- [b-ETSI TS 101 548] ETSI TS 101 548 V2.1.1 (2016), *Access, Terminals, Transmission and Multiplexing (ATTM); European Requirements for Reverse Powering of Remote Access Equipment.* + + + +## **SERIES OF ITU-T RECOMMENDATIONS** + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.119-201612-I_PDF-E/raw.md b/marked/K/T-REC-K.119-201612-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..f2385db52835f710d8e70dae97d20272e7dd9e5a --- /dev/null +++ b/marked/K/T-REC-K.119-201612-I_PDF-E/raw.md @@ -0,0 +1,642 @@ + + +International Telecommunication Union + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.119** + +(12/2016) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Conformance assessment of radio base stations +regarding lightning protection and earthing** + +Recommendation ITU-T K.119 + +![ITU logo](6ed175c791b5e156d9c98a8dbcc3318c_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a red lightning bolt striking it, symbolizing telecommunications and protection against interference. To the right of the globe, the text "International Telecommunication Union" is written in a blue sans-serif font, with "ITU" in a larger, bold font above it. + +ITU logo + + + +# Recommendation ITU-T K.119 + +# Conformance assessment of radio base stations regarding lightning protection and earthing + +## Summary + +Recommendation ITU-T K.119 provides the technical requirements and measurement methods to assess the validity and reliability of the lightning protection and earthing system of radio base stations (RBSs). It focuses on the quality control in the process of construction, acceptance, inspection and maintenance. + +Normally, the conformance assessment is carried out during and immediately after the construction period and it results in the commissioning of the installation to start its operation. Routine inspections are scheduled in order to assure the maintenance of the lightning protection and earthing characteristics, during the operation life of the installation. + +Depending on the function and installation location, the lightning protection system of an RBS can be partitioned into 4 parts which consist of an air-termination and down conductor system, earthing system, equipotential bonding network and surge protective devices (SPDs). The conformance assessment is directed to these parts, and may consist in visual inspection, measurement, analysis and other applicable methods. + +The assessment requirements of each part for commissioning and routine inspections are presented in clauses 8 to 11 separately. In addition, management rules are introduced in clause 12, which are effective for conformance maintenance during the operation life of the RBS. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.119 | 2016-12-14 | 5 | 11.1002/1000/13135 | + +## Keywords + +Assessment, conformance, earthing, lightning protection, radio base station. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2017 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|------|----------------------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 3.1 | Terms defined elsewhere ..... | 1 | +| 3.2 | Terms defined in this Recommendation..... | 2 | +| 4 | Abbreviations and acronyms ..... | 2 | +| 5 | Conventions ..... | 2 | +| 6 | General..... | 2 | +| 6.1 | Commissioning..... | 3 | +| 6.2 | Routine inspection ..... | 3 | +| 7 | Constitution of the lightning protection and earthing system of RBSs ..... | 4 | +| 8 | Air-termination and down conductor system ..... | 5 | +| 8.1 | Requirements for commissioning..... | 6 | +| 8.2 | Requirements for routine inspections ..... | 6 | +| 9 | Earthing system ..... | 6 | +| 9.1 | Requirements for commissioning..... | 7 | +| 9.2 | Requirements for routine inspections..... | 8 | +| 10 | Equipotential bonding network..... | 9 | +| 10.1 | Requirements for commissioning..... | 9 | +| 10.2 | Requirements for routine inspections..... | 11 | +| 11 | Requirements for surge protective devices (SPDs) ..... | 12 | +| 11.1 | Requirements for commissioning..... | 12 | +| 11.2 | Requirements for routine inspections..... | 12 | +| 12 | Management of the conformance assessment..... | 13 | +| 12.1 | File management ..... | 13 | +| 12.2 | Interval of routine inspections ..... | 13 | +| | Appendix I – Test of the DC parameters of MOV SPDs..... | 14 | +| I.1 | Test apparatus ..... | 14 | +| I.2 | Test method ..... | 14 | +| I.3 | Evaluation criteria ..... | 15 | +| | Bibliography..... | 17 | + + + +# Recommendation ITU-T K.119 + +## Conformance assessment of radio base stations regarding lightning protection and earthing + +# 1 Scope + +This Recommendation provides the technical requirements and measurement methods to assess the validity and reliability of the lightning protection and earthing system of radio base stations (RBS). It focuses on the quality control of the processes of construction, acceptance, inspection and maintenance. + +The detailed requirements for the lightning protection of RBSs are provided by [ITU-T K.56], [ITU-T K.112] and their references. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.56] Recommendation ITU-T K.56 (2010), *Protection of radio base stations against lightning discharges*. +- [ITU-T K.111] Recommendation ITU-T K.111 (2015), *Protection of surrounding structures of telecommunication towers against lightning*. +- [ITU-T K.112] Recommendation ITU-T K.112 (2015), *Lightning protection, earthing and bonding: practical procedures for radio base stations*. +- [IEC 61643-11] IEC 61643-11 (2010), *Low-voltage surge protective devices – Part 11: Surge protective devices connected to low-voltage power systems – Requirements and test methods*. +- [IEC 61643-21] IEC 61643-21 (2012), *Low voltage surge protective devices – Part 21: Surge protective devices connected to telecommunications and signalling networks – Performance requirements and testing methods*. +- [IEC 62305-3] IEC 62305-3 (2010), *Protection against lightning – Part 3: Physical damage to structures and life hazard*. + +# 3 Definitions + +### 3.1 Terms defined elsewhere + +The definitions contained in the references apply to this Recommendation. Some of them are reproduced here for convenience. + +**3.1.1 earth conductor** [b-ITU-T Handbook]: A conductor or group of conductors connecting the earth electrode to the earth collector. In the case of partly buried connections, this definition is valid only for the sections which are electrically insulated from the ground, the sections in contact with the ground forming part of the earth electrode. + +**3.1.2 earthing network** [ITU-T K.112]: The part of an earthing installation that is restricted to the earth electrodes and their interconnections. + +**3.1.3 one-port SPD** [b-IEC 61643-11]: SPD having no intended series impedance. + +NOTE – A one port SPD may have separate input and output connections. + +**3.1.4 two-port SPD** [b-IEC 61643-11]: SPD having a specific series impedance connected between separate input and output connections. + +### **3.2 Terms defined in this Recommendation** + +This Recommendation defines the following terms: + +**3.2.1 commissioning:** Acceptance of the whole installation that is carried out when all the work has been finished and the installation complies with the design criteria. + +**3.2.2 final inspection:** Inspection that is carried out when all the work has been finished. + +**3.2.3 follow-up inspection:** Inspection performed during the construction work in order to verify the compliance of the installation with the design criteria. + +NOTE – Follow-up inspection is normally required for parts of the installation that are not accessible afterwards (e.g., earthing network). + +**3.2.4 routine inspection:** Inspection that is carried out at regular intervals during the operational life of the installation. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +AC      Alternating Current + +DC      Direct Current + +LPL    Lightning Protection Level + +MET    Main Earthing Terminal + +MOV    Metal Oxide Varistor + +RBS    Radio Base Station + +SPD    Surge Protective Device + +# **5 Conventions** + +None. + +# **6 General** + +In order to ensure the validity and reliability of the lightning protection and earthing system, its assessment and maintenance should be carried out throughout the entire lifetime of the radio base station. According to the different requirements during the construction period and the operation period, the assessment can be divided into two categories: commissioning and routine inspections. + +Effective management procedures also have to be implemented for conformance assessment, such as documentation management and a periodic inspection schedule. Moreover, the conformance assessment shall be implemented by skilled professionals and the measuring equipment (e.g., earthing resistance meter) shall have a valid calibration. + +### 6.1 Commissioning + +During the construction period, a systemic assessment should be performed to ensure that the lightning protection and earthing system satisfies the requirements of design, which is regarded as the acceptance of the project. The follow-up inspection shall be applied to the concealed works (e.g., embedded electrodes). After the installation, a final inspection shall be exerted for all the components. + +The primary aspects needed to be considered for commissioning an RBS include: + +- the installation shall conform to the project requirements; +- the applied materials and devices are in good condition and capable of performing their designed functions; +- the construction technology and quality of the supplies are adequate for environmental suitability and service life. + +The RBS shall be commissioned to start its operation only if both the results of the follow-up and final inspections comply with the requirements. + +## 6.2 Routine inspection + +During the operating period, regular and periodic inspections are fundamental for the reliable maintenance of all the components in the lightning protection and earthing system, which is regarded as routine inspection. The interval between consecutive routine inspections needs to consider the nature of RBS and environmental factors. An unordered inspection may need to be performed at some emergency conditions. The property owner shall be informed of all observed faults and they shall be repaired without delay. + +The primary aspects that need to be considered in routine inspections include: + +- all components of the lightning protection and earthing system are in good condition and capable of performing their designed functions, and that there is no corrosion; +- any recently installed equipment or constructions are incorporated into the lightning protection and earthing system; +- any remaining effect caused by lightning flashes or natural calamities (e.g., flood, earthquake) or nearby constructions shall be assessed and removed. + +Any problem detected during the routine inspections must be corrected in order to make sure that the installation complies with the requirements of the inspection. + +Figure 1 shows a flowchart of the conformance assessment process according to this Recommendation. + +![Flowchart of the conformance assessment process. The process starts with 'START', followed by 'Follow-up inspection', a decision 'OK?'. If 'N' (No), it goes to 'Fix the problems' and loops back to 'Follow-up inspection'. If 'Y' (Yes), it goes to 'Final inspection', another decision 'OK?'. If 'N', it goes to 'Fix the problems' and loops back to 'Final inspection'. If 'Y', it goes to 'RBS commissioned', then 'Wait for the next inspection', then 'Routine inspection', and finally a decision 'OK?'. If 'N', it goes to 'Fix the problems' and loops back to 'Routine inspection'. If 'Y', it loops back to 'Wait for the next inspection'. The diagram is labeled K.119(16)_F01.](a5ee5c23b6dc52ec1d724b76d5a5f58f_img.jpg) + +``` + +graph TD + START([START]) --> FUI[Follow-up inspection] + FUI --> OK1{OK?} + OK1 -- N --> FP1[Fix the problems] + FP1 --> FUI + OK1 -- Y --> FI[Final inspection] + FI --> OK2{OK?} + OK2 -- N --> FP2[Fix the problems] + FP2 --> FI + OK2 -- Y --> RC[RBS commissioned] + RC --> WNI[Wait for the next inspection] + WNI --> RI[Routine inspection] + RI --> OK3{OK?} + OK3 -- N --> FP3[Fix the problems] + FP3 --> RI + OK3 -- Y --> WNI + +``` + +K.119(16)\_F01 + +Flowchart of the conformance assessment process. The process starts with 'START', followed by 'Follow-up inspection', a decision 'OK?'. If 'N' (No), it goes to 'Fix the problems' and loops back to 'Follow-up inspection'. If 'Y' (Yes), it goes to 'Final inspection', another decision 'OK?'. If 'N', it goes to 'Fix the problems' and loops back to 'Final inspection'. If 'Y', it goes to 'RBS commissioned', then 'Wait for the next inspection', then 'Routine inspection', and finally a decision 'OK?'. If 'N', it goes to 'Fix the problems' and loops back to 'Routine inspection'. If 'Y', it loops back to 'Wait for the next inspection'. The diagram is labeled K.119(16)\_F01. + +**Figure 1 – Flowchart of the conformance assessment process** + +# 7 Constitution of the lightning protection and earthing system of RBSs + +Depending on the function and installation location, the lightning protection and earthing system of an RBS can be partitioned as follows: + +- air-termination and down conductor system; +- earthing system; +- equipotential bonding network; +- surge protective devices (SPDs). + +Figure 2 shows the parts of an RBS where it can be seen that each part has its main function and need to coordinate with the other parts. The malfunction or degradation of any part can affect the overall performance and even lead to a hazardous result. The common important components belonging to each part are listed in Table 1. + +NOTE – The lightning protection and earthing system of roof-top RBSs can also be partitioned into the above 4 parts, although the layout of an external system may have some differences. + +Correspondingly, the assessment of conformance can be partitioned into the itemized evaluation for each part through visual inspection, measurement, analysis and other applicable methods. + +![Figure 2: Typical layout of RBS consisting of all the important constituent parts. The diagram shows a cross-section of a radio base station (RBS) structure. On the left, a building contains two 'Equipment' units. Above the building is an 'Air-termination conductor (if needed)'. A 'Bonding ring' is connected to the building's structure, with a 'Bonding conductor' leading to the equipment. A 'Feeder SPD (if needed)' is shown on the power line. To the right of the building is a tower with an 'Antenna' and an 'Air-termination rod'. A 'Down conductor (if needed)' runs down the tower. 'Feeder cable bonding' is indicated on the tower. Inside the building, there's a 'Bonding bar' connected to the 'Earth conductor', which leads to the 'Earthing network'. Another 'SPD' is shown on the signal line. Outside the building, a 'Power meter' is connected to an 'SPD'. The diagram is labeled with numbers ① to ④ corresponding to the legend below. The code 'K.119(16)_F02' is in the bottom right corner.](cfef993dcc8fb513de79eb1f93cf26ae_img.jpg) + +K.119(16)\_F02 + +① air-termination and down conductor system      ② earthing system + ③ equipotential bonding network                      ④ SPDs + +Figure 2: Typical layout of RBS consisting of all the important constituent parts. The diagram shows a cross-section of a radio base station (RBS) structure. On the left, a building contains two 'Equipment' units. Above the building is an 'Air-termination conductor (if needed)'. A 'Bonding ring' is connected to the building's structure, with a 'Bonding conductor' leading to the equipment. A 'Feeder SPD (if needed)' is shown on the power line. To the right of the building is a tower with an 'Antenna' and an 'Air-termination rod'. A 'Down conductor (if needed)' runs down the tower. 'Feeder cable bonding' is indicated on the tower. Inside the building, there's a 'Bonding bar' connected to the 'Earth conductor', which leads to the 'Earthing network'. Another 'SPD' is shown on the signal line. Outside the building, a 'Power meter' is connected to an 'SPD'. The diagram is labeled with numbers ① to ④ corresponding to the legend below. The code 'K.119(16)\_F02' is in the bottom right corner. + +**Figure 2 – Typical layout of RBS consisting of all the important constituent parts** + +**Table 1 – The constituent parts and the corresponding components** + +| Parts | Components | +|-------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Air-termination and Down conductor system | Air-termination rod or mesh
Down conductors | +| Earthing system | Earthing network
Earth conductor | +| Equipotential bonding network | Internal equipotential bonding (e.g., bonding conductor for equipment and devices)
External equipotential bonding (e.g., bonding of the tower and feeder cable outside the equipment room) | +| Surge protective devices (SPDs) | Electric power SPDs
Signal and communication SPDs | + +# 8 Air-termination and down conductor system + +The air-termination and down conductor system is intended to intercept direct lightning flashes to the antennae or structure and conduct the lightning current from the point of strike to earth. + +## 8.1 Requirements for commissioning + +The following items shall be verified for commissioning: + +- The height, position, size and materials of an air-termination and down conductor system should conform to the design and the corresponding requirements regulated in [ITU-T K.112]. +- Inspect and ensure that the antennae, the structure and other outdoor installations are protected by an air-termination rod (mesh). If needed, after the installation of antennae, a height indicator is used to determine the actual height of the air-termination rod and antennae to estimate the validity of protection for direct strikes. The estimation method shall refer to [ITU-T K.112]. +- The down conductors should be away from sewage tubes and drains when they are installed below the earth surface. The down-conductor section that is above the earth surface shall be protected against mechanical damage. +- Inspect the reliability of welding and anticorrosion for all welding points or connecting points. For the welding of flat steel conductors, the minimum overlap length should be not less than twice the width of the flat steel conductor. For the welding of round steel conductors, the minimum overlap length should be not less than 10 times the diameter of the round steel conductor. The anticorrosion protection of the connecting points or welding points can be achieved by wrapping these connections with waterproof tape or coating them with anticorrosion paint, silica gel or asphalt. If they are buried in concrete, the follow-up acceptance should apply and the anticorrosion can be ignored. If a down conductor is partially inserted into the earth, anticorrosion and anti-rust measures must be taken for the part 50 cm above the earth surface and the part 50 cm below the earth surface. +- If the down conductors of the building can be shared for a roof-top RBS, the validity of down conductors should conform in accordance with [ITU-T K.112] through consulting the design documentation of the building. + +## 8.2 Requirements for routine inspections + +The routine inspections are recommended to be performed before lightning season. The following items shall be verified: + +- The connection conditions of the air-termination and down conductor system should be inspected periodically, especially for the points of welding or bonding. If there is evidence of breaks, looseness, mechanical damage or corrosion, corrective measures should be implemented as soon as possible. When the corroded part is greater than one third of the cross-section area of the down conductor, the down conductor shall be replaced. +- If the down conductors are concealed, the measurement of the bonding resistance shall be performed and the measured value shall be below 0.2 Ω. More detailed information about the measurement method is provided in [IEC 62305-3; Annex E]. +- Any extraneous installation (e.g., TV antenna, metal lines) must not be hanged or connected to the tower, which should be inspected by maintainers frequently. + +# 9 Earthing system + +The earthing system is intended to disperse the lightning current into the earth and provides a basic equipotential platform for the interconnected structures and installations in an RBS. + +### 9.1 Requirements for commissioning + +#### 9.1.1 General + +When a building and an earthing network is to be constructed for an RBS, the follow-up inspection shall be carried out in order to assure that the earthing network and its connections comply with the project requirements. This is important as because of the configuration of the earthing electrodes these are no more accessible once they are buried in the soil. + +When the RBS is installed in a rented building, the validity of building foundation should conform to [ITU-T K.112] through consulting the documentation of the building. Moreover, prior to connecting earth conductors to the building steelwork, the overall electrical continuity of the steelwork shall be verified. The measured resistance between parts of the steelwork used as a part of the earthing system shall be below $0.2\ \Omega$ . + +When earthing resistances need to be measured, the measuring method should refer to Annex A of [ITU-T K.112]. + +#### 9.1.2 Requirements for follow-up inspections + +The actual implementation of an earthing system shall be plotted as one of the acceptance files which can give an important reference for the subsequent maintenance. After the construction phase, it is nearly impossible to determine the layout and construction of the earthing system. Therefore, the layout should be well documented. This can be done utilizing drawings, descriptions and photographs taken during construction. + +The following items should be considered during the period of construction: + +- The shape, dimensions and materials of the earthing network should conform to the requirements of design and the corresponding requirements regulated in [ITU-T K.112]. +- Inspect the depth of electrodes. The embedded depth and the type of earth electrodes shall be such as to minimize the effects of corrosion, soil drying and freezing and thereby stabilize the conventional earth resistance. The depth of the conductor shall be at least 0.5 m. On bare solid rock or thin soil district, the depth requirement can be relaxed but the electrodes are not permitted to be exposed on the surface of the ground due to rain erosion. On freezing regions, it is recommended that the upper part of a vertical earth electrode within the freezing soil should not be regarded as effective under frost conditions. +- Inspect the separation from other installations. The embedded electrodes shall have a safe separation with other buried installations, such as buried telecommunication cables, power cables, pipes, etc. Table 2 gives the recommended safe distances from common installations. The distance of the buried electrode from the associated structure shall be approximately 1.0 m. +- Inspect the reliability of welding and anticorrosion. For the welding of flat steel conductors, the minimum overlap length should be not less than twice the width of the flat steel. For the welding of round steel conductors, the minimum overlap length should be not less than 10 times the diameter of the round steel. The anticorrosion protection of the connecting points or welding points can be achieved by wrapping these connections with waterproof tape or coating them with anticorrosion paint, silica gel or asphalt. +- Inspect the backfill of ditches. The soil is permitted to backfill only if the electrodes have been accepted by an inspector. The bigger rocks need be screened out from the backfilled soil. The soil shall be tamped down to avoid the sedimentation of the surface. On the district with a large slope or severe soil loss, it is required to cover concrete or grass on the surface of the earthing network to avoid the exposure of electrodes due to rain erosion. + +**Table 2 – Recommended safe distances from buried installations for earthing electrodes (cm)** + +| Type of installation | Crossover | Horizontal | +|--------------------------------------------------------------------------------|------------------------|------------| +| Low-voltage cable, fibre cable, telecommunication cable serving the RBS (Note) | 20 | 20 | +| High-voltage cable serving the RBS (Note) | 50 | 100 | +| Other metallic installations | Refer to [ITU-T K.111] | | + +NOTE – All the installations serving the RBS shall be connected to the earthing network through hard wires or SPDs at the entrance; if the installations are placed in pipes, the distance can be disregarded. + +#### 9.1.3 Requirements for the final inspection + +- The resistance of the earthing network shall be measured after the installation. The measured value shall satisfy the designed requirement or the regulated value in national regulations, if any. +- The earth conductors shall be installed in a manner that they provide the shortest and most direct path to earth. They shall not be installed in gutters or water spouts, even if they are covered by insulating material. +- The welding and bonding point of earth conductors shall be inspected to ensure the reliability of welding and anticorrosion. +- The section that is above the earth surface shall be protected against mechanical damage. + +### 9.2 Requirements for routine inspections + +The earthing system should be inspected and measured periodically. The normal methods are visual inspection and resistance measurement which are described in the following clauses. The inspection is recommended to be performed before lightning season. In normal conditions, the routine inspection should be implemented according to Table 3. The frequency of routine inspections may increase, depending on the following factors: + +- the earthing electrodes are made of two or more types of materials; +- the surrounding soil includes chemical components, such as acid, alkali, salt, etc.; +- there are highly corrosive installations, such as strengthening a sewage tank, drainage ditch, industrial plant; +- resistance reducing backfill is used in the earthing system. + +#### 9.2.1 Visual inspection + +The visual inspection shall include: + +- Check whether the surface soil is lost due to rain erosion. When there is the collapse, crack or down punching of soil in the ditches or hollow under the concrete surface, the corresponding preventive and remedial measures should be taken in time. +- Check whether the earth conductors are firm and complete. When there are cases related to broken, looseness, mechanical damage and corrosion, the remedy measures should be implemented as soon as possible. When the corrosion part is beyond one third of the cross-section area, the conductor should be replaced in time. +- When the life of electrodes made of galvanized steel is beyond 15 years, it is recommended to dig out some typical points as samples to estimate the corrosion and reliability condition. The selected points are distributed in different directions and the number shall be not less than 4. According to the inspection results, the efficiency of an earthing network can be estimated. When the corrosion part is beyond one third of the cross-section area of the electrode, the affected earthing electrodes shall be replaced. + +#### 9.2.2 Measurement and estimation + +- The resistance of the earthing network shall be measured annually. The measured value shall satisfy the designed requirement or the regulated value in national regulations, if any. The test should not be performed on rainy days. The information including apparatus, test layout and weather shall be recorded for subsequent estimations. +- When the measured resistance values show larger changes than anticipated in the design, especially when the resistance increases steadily between inspections, additional investigations should be made to determine the reason for the changes. +- If the reason for unexpected changes in the earthing resistance cannot be found, it is recommended to dig out some typical points as samples, in order to estimate the corrosion and reliability condition. If there is evidence of breaks, looseness, mechanical damage or corrosion, the remedy measures should be implemented as soon as possible. + +NOTE – The judgement of "large changes" shall consider the circumstance and weather factors (e.g., rainy or dry season), which may influence the measured value. + +#### 9.2.3 Assessment for outside threat + +When there are the constructions of underground pipelines or foundations in the vicinity of electrodes, the owner of the earthing network needs to determine whether these constructions affect the mechanical reliability and anticorrosion properties. If this risk exists, the appropriate precautions shall be taken through negotiation with the parts involved. + +When a natural calamity (e.g., flood, earthquake) occurs nearby, the reassessment should be implemented according to clauses 9.2.1 and 9.2.2. + +# 10 Equipotential bonding network + +The equipotential bonding network is intended to provide an optimized equipotential platform for the different metal parts on the basis of the earthing network. + +According to its position in the installation, it can be divided into internal and external equipotential bonding networks. The former includes the bonding bar (ring) and bonding conductor for equipment and devices in the machine room. The latter includes the bonding for the tower and feeder cable outside the equipment room. + +### 10.1 Requirements for commissioning + +#### 10.1.1 Internal equipotential bonding network + +For the first assessment, the following requirements for the internal equipotential bonding network should be considered: + +- The configuration, dimensions and materials of internal equipotential bonding network should conform to the requirements of design and related recommendations. +- The cross-section of bonding conductors shall be determined according to the mechanical strength of materials and the maximum expected fault current, if any. Generally, the minimum size for bonding conductors should be $16\text{ mm}^2$ for mechanical robustness. Smaller size conductors may be used where the conductors are protected against mechanical damage and a coarser size is normally not needed for current-carrying capacity. +- Bonding conductors shall be connected to a bonding bar (ring) constructed and installed in such a way that it allows easy access for inspection. For the parts that are not visible for inspection, the measurement of electrical continuity should be performed. + +- Both ends of the bonding conductor should be labelled to indicate the connected equipment or bonding bar. For labelling, use stencilled labels or other permanent labelling methods. The laying of bonding conductors shall be firmly bandaged, neat and straight. +- The size of the wiring terminals shall match with the diameter of bonding conductors. The place where wiring terminals and equipment contact with bonding bars shall be smooth and fastened, without rusting or oxidation. The copper wiring terminals must be mounted and pressed (welded) tightly. When bonding bars are interconnected with bonding conductors via different metal materials, electrochemical corrosion shall be prevented. +- Bare surfaces should be coated with an appropriate antioxidant compound before crimp connections are made. All unplated connectors, braided straps and bus bars should be brought to a bright finish and then coated with an antioxidant before they are connected. Tinned, solder-plated or silver-plated connectors and other plated connection surfaces do not have to be prepared in this manner, but they should be clean and free of contaminants. +- All raceway fittings should be tightened to provide a permanent low-impedance path. +- The same bolt assemblies should not secure multiple connectors. +- Non-conductive coatings (such as paint, lacquer and enamel) on equipment to be bonded or grounded should be removed from threads and other contact surfaces to assure electrical continuity. +- The fibre splice tray should be connected to the main earthing terminal (MET) directly. If an optical fibre has metal strength members, the metal strength members must be bonded to the fibre splice tray. The fibre splice tray should be insulated from other metallic parts in the equipment room. +- The metallic shield of shielded cables shall be connected to equipment metallic frames at both ends. The external conductor of feeder cables shall be connected to the equipment frames. +- The metallic ducts or trays that carry the cabling shall be connected to the equipment metallic frame (or structure) at both ends, as shown in Figure 3. + +![Figure 3: Lateral view of the RBS showing the bonding between the internal tray and equipment frame. The diagram illustrates a cross-section of a building wall with an internal tray and external tray. Two equipment frames are shown inside the building. Bonding conductors connect the internal tray to the equipment frames. A feeder cable enters from the external tray, passing through the building wall. The external tray is connected to an external earthing bar, which is further connected to a ring electrode. The diagram is labeled with 'Building wall', 'Internal tray', 'Feeder', 'External tray', 'Bonding', 'Equipment frame', 'MEB', 'External earthing bar', and 'To the ring electrode'. The code 'K.119(16)_F03' is visible in the bottom right corner.](5cab96b2d23174c25919840ecd50aa48_img.jpg) + +Figure 3: Lateral view of the RBS showing the bonding between the internal tray and equipment frame. The diagram illustrates a cross-section of a building wall with an internal tray and external tray. Two equipment frames are shown inside the building. Bonding conductors connect the internal tray to the equipment frames. A feeder cable enters from the external tray, passing through the building wall. The external tray is connected to an external earthing bar, which is further connected to a ring electrode. The diagram is labeled with 'Building wall', 'Internal tray', 'Feeder', 'External tray', 'Bonding', 'Equipment frame', 'MEB', 'External earthing bar', and 'To the ring electrode'. The code 'K.119(16)\_F03' is visible in the bottom right corner. + +**Figure 3 – Lateral view of the RBS showing the bonding between the internal tray and equipment frame** + +- The metallic ducts and trays shall be electrically continuous for their entire length. The continuity at joints shall be achieved at least in two symmetrically spaced points (e.g., by the use of two bonding clamps on the sides of the tray), as shown in Figure 4. + +![Diagram showing the details of electrical continuity in trays and equipment frame. It illustrates a cable tray connected to an equipment frame via joints. The cable tray is shown in two sections, with joints indicated by arrows pointing to the connection points. The equipment frame is shown as a solid base. The diagram is labeled 'K.119(16)_F04'.](ac852a162572ca8a8c8478c49b571af5_img.jpg) + +Diagram showing the details of electrical continuity in trays and equipment frame. It illustrates a cable tray connected to an equipment frame via joints. The cable tray is shown in two sections, with joints indicated by arrows pointing to the connection points. The equipment frame is shown as a solid base. The diagram is labeled 'K.119(16)\_F04'. + +**Figure 4 – Details of the electrical continuity in trays and equipment frame** + +- Two-hole compression-type connectors are preferred for making connections to flat surfaces (such as bus bars, frames, racks or cabinets). The reason for this is to prevent the loosening of connections. Torque and bolt assembly requirements for securing the connector should be as specified by the connector supplier. Nuts, bolts, washers and lock washers should be of high quality bronze or stainless steel alloy or equivalent. +- Connection devices or fittings that depend solely on solder should be avoided. A soldering lug, a screwless (push-in) connector or a quick-connect or other friction-fit connector shall not be used to terminate a bonding or earthing conductor. + +#### 10.1.2 External equipotential bonding network + +The following requirements for external equipotential bonding networks should be considered for commissioning: + +- The facilities and equipment within a metallic shell installed on the tower shall be bonded to the tower directly. If the conductor terminal cannot be connected to the tower directly, it shall be bonded to a bonding bar first and the bonding bar shall be bonded to the tower. +- The feeder cable should be bonded at the top of the tower and at the bonding bar near the feeder window. The connection at the point where they leave the tower (bending point) depends on the length of the horizontal section of the feeder tray, according to [ITU-T K.56]. +- The feeder tray shall be continuous and bonded to the tower and to the earthing bar located near the feed-through window of the building. +- All the connections must be mounted and pressed (welded) tightly and the electrochemical corrosion shall be prevented. +- If the conductors supplying power to the tower lights (lighting cable) are installed inside a metallic duct or if they are shielded, the metallic duct or the shield shall be bonded to the bonding bar located near the feed-through window. In both cases, the bonding shall be made by means of a conductor as short as possible. + +### 10.2 Requirements for routine inspections + +Visual inspection shall be carried out to verify that: + +- there are no loose connections or any accidental breaks in conductors and joints; +- no part of the system has been weakened due to corrosion; +- bonding conductors and cable shields are intact and interconnected; +- appropriate line routings are maintained. + +If there are cases related to breaks, looseness, mechanical damage or corrosion, the remedy measures should be implemented as soon as possible. + +When there are additions or alterations, it shall be checked that the scheme of the bonding configuration is modified by these additions or alterations. More detailed information about the requirements for bonding configurations are provided by [ITU-T K.112]. + +# **11 Requirements for surge protective devices (SPDs)** + +The SPDs are intended to provide an equipotential bonding between the live parts of incoming wires and local earth, in order to ensure that the residual overvoltages are less than the inherent resistibility of the equipment. + +### **11.1 Requirements for commissioning** + +The following items should be verified for commissioning: + +- The capacity, installation position and other parameters of the coordinated SPDs should conform to the requirements of design. The requirements of power and signal SPDs should refer to [IEC 61643-11] and [IEC 61643-21] respectively. +- Inspect the alarm unit or status indicator of SPDs and ensure the validity of the operating state. If the SPDs have no indicators, the protected equipment and circuits shall be inspected for any evidence of equipment malfunction. Special attention should be paid to the effect of SPDs on the transmission performance due to its installation in series with signal or telecommunication circuits. +- The lead and bonding conductor of SPDs shall be made as direct and straight as possible. For power SPDs, the length of lead conductors shall be less than 0.5 m and the length of bonding conductors shall be less than 1.5 m. For Class I and Class II power SPDs, the minimum cross-sectional area of the lead and bonding conductor is 16 mm2. +- The coaxial SPDs for a feeder cable and other signal SPDs, if they are needed according to [ITU-T K.56], shall be installed near the protected equipment. Their bonding conductors shall be directly connected to the bonding bar of the equipment. + +NOTE – In some countries, the bonding conductors of coaxial SPDs are required to be connected to the outdoor bonding bar. + +- The lead and bonding conductors shall be connected and fastened via wiring terminals or copper pigtails. When copper pigtails are connected with cable cores, they shall be secured by hydraulic clamps or treated by dip soldering. These conductors shall be laid in order and fixed at racks. The routing shall be short and straight, without loops. + +### **11.2 Requirements for routine inspections** + +The periodic assessment for SPDs should be implemented at least once per year. For the RBSs with a high risk of lightning strikes, it is recommended that the visual inspection of the coordinated SPDs is integrated into the scope of the routine inspection and maintenance for the equipment. + +The following items shall be verified: + +- Inspect the alarm unit or status indicator of SPDs. When a failure is displayed, the SPD should be replaced without delay. If an SPD does not have a visual indicator, measurements shall be performed in accordance with the manufacturer's instructions to confirm its operating status, when so required. +- Inspect the operation state of the external disconnectors of SPDs if they exist. When the disconnector is found operated or broken, it should be switched on or replaced immediately. If the disconnector cannot be switched on, the problem shall be fixed or the SPD / disconnector shall be replaced. +- Inspect the connection reliability of the lead and bonding conductors of SPDs. If the conductors are found loose or twisted, the problem shall be fixed. + +- It is recommended to implement a periodical test on the DC parameters of SPDs for the voltage-limited SPDs using metal oxide varistors (MOV). The inconformity of test results means that the performance of the SPDs has been compromised and that the SPD should be replaced in time. Appendix I gives the test method and the evaluation criteria. +- When the system is expanded or the equipment is changed, it should be ensured that these alterations would not affect the coordination performance of SPDs. +- For the two-port SPD or one port-SPD with separate input / output terminals, it should be ensured that the current consumption of the downstream equipment does not exceed the rated current capacity of the SPD. + +# 12 Management of the conformance assessment + +### 12.1 File management + +When the lightning protection and earthing system of an RBS is put into service, the relevant documentation shall be constructed at the same time. The complete documents about the lightning protection and earthing system shall include: + +- design files and acceptance reports +- previous inspection reports +- previous maintenance records +- damage records of equipment, if they exist. + +### 12.2 Interval of routine inspections + +The interval between successive routine inspections needs to consider the protection level of the RBS, the nature of its parts and the environmental factors. Where no specific requirements are identified by the authority having jurisdiction, the values of Table 3 are recommended. + +**Table 3 – Recommended interval of routine inspections (years)** + +| Component
LPL (Note 1) | Air-termination and down conductor system (Note 2) | Earthing system (Note 3) | Equipotential bonding system | | SPDs | +|---------------------------|----------------------------------------------------|--------------------------|------------------------------|-------------------|------| +| | | | Internal | External (Note 2) | | +| I and II | 2 | 2 | 2 | 2 | 1 | +| III and IV | 4 | 4 | 4 | 4 | 1 | + +NOTE 1 – Normally, the LPL for an RBS is determined during the design period and the relative information can refer to [ITU-T K.56]. + +NOTE 2 – Considering the difficulty in inspecting high towers, the inspection of external equipotential bonding networks can be integrated into the scope of the routine maintenance for antennae and feeder cables. + +NOTE 3 – When there are the special factors described in clause 9.2, the frequency may be increased. + +In addition, an extraordinary inspection needs to be performed under the following conditions: + +- when a significant alteration or repair is made to the components of lightning protection and earthing system; +- when an altered equipment or system may affect the whole performance of the lightning protection and earthing system; +- when the natural calamities (e.g., flood, earthquake) or nearby constructions may affect the whole performance of the lightning protection and earthing system; +- when damage due to lightning strikes occurs. + +## Appendix I + +## Test of the DC parameters of MOV SPDs + +(This appendix does not form an integral part of this Recommendation.) + +This test is only suited for voltage-limiting SPDs using metal oxide varistors (MOV) without filtration or current limiting elements. When the voltage-limited SPDs are installed in the low-voltage power distribution system, there is a leakage current in the order of microamperes flowing through SPDs. If the value of the current is relatively high, it means that the SPD performance has degraded and that the SPD should be replaced in time. The comparison of varistor voltages (at 1 mA) can be a supplementary method used for this evaluation. + +### I.1 Test apparatus + +The selected test apparatus could be a lightning protection element tester or other similar apparatus with corresponding functions. Figure I.1 gives a typical example of a lightning protection element tester. + +NOTE – Some manufacturers of SPDs provided a dedicated test apparatus for this test. + +![Figure I.1: A typical example of apparatus for the test of the DC parameters of MOV SPDs. The image shows a grey rectangular test unit with a digital display and several buttons. Two red and black test leads with alligator clips are connected to the front panel and coiled in front of the unit.](1fd4fda95d22e337df091dfa8fa80f90_img.jpg) + +Figure I.1: A typical example of apparatus for the test of the DC parameters of MOV SPDs. The image shows a grey rectangular test unit with a digital display and several buttons. Two red and black test leads with alligator clips are connected to the front panel and coiled in front of the unit. + +Figure I.1 – A typical example of apparatus for the test of the DC parameters of MOV SPDs + +### I.2 Test method + +If the SPDs are pluggable, these SPDs can be plugged out for test. If not, disconnect the lead conductors and test each line in order, as showed in Figure I.2. + +![Figure I.2: Layout for SPD testing. This is a circuit diagram showing a 'Test apparatus' connected to an SPD. The SPD is represented by a dashed box containing four varistor symbols. The input lines are labeled L1, L2, L3, and N. The L1 line is connected to the test apparatus. The other three lines (L2, L3, and N) are connected to a common ground symbol. The test apparatus is also connected to this common ground. The diagram is labeled K.119(16)_FI.2 at the bottom right.](d79d33da852cb7bca3e87b400a15c3e8_img.jpg) + +Figure I.2: Layout for SPD testing. This is a circuit diagram showing a 'Test apparatus' connected to an SPD. The SPD is represented by a dashed box containing four varistor symbols. The input lines are labeled L1, L2, L3, and N. The L1 line is connected to the test apparatus. The other three lines (L2, L3, and N) are connected to a common ground symbol. The test apparatus is also connected to this common ground. The diagram is labeled K.119(16)\_FI.2 at the bottom right. + +Figure I.2 – Layout for SPD testing + +The measured values shall be recorded, in order to assess its evolution in time (from one inspection to the next one) and the performance of the SPDs. Table I.1 gives an example of the form for this measurement. + +**Table I.1 – Example of form for SPD data** + +| Date | Measured varistor voltage
(V) | Measured leakage current
(mA) | +|-------------|------------------------------------------|------------------------------------------| +| | | | +| | | | +| | | | + +### I.3 Evaluation criteria + +For the evaluation criteria described in this clause, varistor voltage $U_V$ is the voltage across the varistor when it conducts a current equal to 1 mA. This value is usually provided by the manufacturer. + +The SPD is considered as degraded when at least one of the following conditions is met: + +- leakage current. + +The leakage current value measured at 75% $U_V$ drifts upward progressively: + +- varistor voltages. + +The measured varistor voltage ( $U_V$ ) is not within the permitted range specified by the manufacturer or the measured value drifts downward progressively. If specific information is not provided, the deviation of the measured value should be less than 10% comparing with the initial test value and the corresponding rated varistor voltage. Table I.2 gives typical values of the rated varistor voltages and the corresponding maximum continued operation voltage for usual voltage-limiting SPDs. + +**Table I.2 – Typical values of varistor voltage and the corresponding maximum continue operation voltage for usual voltage-limiting SPDs (values in Volts)** + +| Rated varistor voltage
(U_V) | Maximum AC continue
operation voltage
(U_C) | Maximum DC continue
operation voltage
(U_{DC}) | +|------------------------------------------------------|-------------------------------------------------------------------------|----------------------------------------------------------------------------| +| 82 | 50 | 65 | +| 100 | 60 | 85 | +| 120 | 75 | 100 | +| 150 | 95 | 125 | +| 200 | 130 | 170 | +| 220 | 140 | 180 | +| 240 | 150 | 200 | +| 270 | 175 | 225 | +| 360 | 230 | 300 | +| 390 | 250 | 320 | +| 430 | 275 | 350 | +| 470 | 300 | 385 | +| 500 | 320 | 410 | + +**Table I.2 – Typical values of varistor voltage and the corresponding maximum continue operation voltage for usual voltage-limiting SPDs (values in Volts)** + +| Rated varistor voltage
(U_V) | Maximum AC continue
operation voltage
(U_C) | Maximum DC continue
operation voltage
(U_{DC}) | +|------------------------------------------------------|-------------------------------------------------------------------------|----------------------------------------------------------------------------| +| 620 | 385 | 505 | +| 680 | 420 | 560 | +| 750 | 460 | 615 | +| 780 | 485 | 640 | +| 820 | 510 | 670 | +| 910 | 550 | 745 | + +## Bibliography + +- [b-ITU-Handbook] ITU-T Handbook (2003), *Handbook on earthing and bonding*. +- [b-IEC 61643-11] IEC 61643-11:2008, *Low-voltage surge protective devices. Part 11: Surge protective devices connected to low-voltage power distribution systems – Performance requirements and testing methods*. + + + + + +## **SERIES OF ITU-T RECOMMENDATIONS** + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.12-202408-I_PDF-E/raw.md b/marked/K/T-REC-K.12-202408-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..1fc2d9a43bd3755717c2af5b6fee01ef09013637 --- /dev/null +++ b/marked/K/T-REC-K.12-202408-I_PDF-E/raw.md @@ -0,0 +1,831 @@ + + +# Recommendation **ITU-T K.12 (08/2024)** + +SERIES K: Protection against interference + +--- + +# **Characteristics of gas discharge tubes for the protection of telecommunication installations** + +![ITU logo](390120de4fe440c42fea8154fcaad334_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with white lines representing latitude and longitude, and the letters 'ITU' in a bold, blue, sans-serif font superimposed on the globe. + +ITU logo + + + +# Recommendation ITU-T K.12 + +# Characteristics of gas discharge tubes for the protection of telecommunication installations + +# Summary + +Recommendation ITU-T K.12 defines the basic characteristics to be met by gas discharge tubes for the protection of exchange and outdoor equipment, subscriber or customer equipment and telecommunication lines from surges. It is intended to be used for the harmonization of existing or future specifications issued by gas discharge tube manufacturers, telecommunication equipment manufacturers, administrations or network operators. + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T K.12 | 1976-10-08 | | 11.1002/1000/10056 | +| 2.0 | ITU-T K.12 | 1980-11-21 | | 11.1002/1000/7842 | +| 3.0 | ITU-T K.12 | 1981-07-21 | 5 | 11.1002/1000/10750 | +| 4.0 | ITU-T K.12 | 1984-10-19 | | 11.1002/1000/6956 | +| 5.0 | ITU-T K.12 | 1988-11-25 | | 11.1002/1000/1376 | +| 6.0 | ITU-T K.12 | 1995-05-31 | 5 | 11.1002/1000/1377 | +| 7.0 | ITU-T K.12 | 2000-02-25 | 5 | 11.1002/1000/4903 | +| 8.0 | ITU-T K.12 | 2006-02-13 | 5 | 11.1002/1000/8739 | +| 9.0 | ITU-T K.12 | 2010-05-29 | 5 | 11.1002/1000/10838 | +| 10.0 | ITU-T K.12 | 2024-08-13 | 5 | 11.1002/1000/16002 | + +## Keywords + +Electrical characteristics and test methods, gas discharge tube (GDT). + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, and information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2024 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|------|----------------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 3.1 | Terms defined elsewhere ..... | 2 | +| 3.2 | Terms defined in this Recommendation..... | 2 | +| 4 | Abbreviations and acronyms ..... | 3 | +| 5 | Conventions ..... | 3 | +| 6 | Storage conditions ..... | 3 | +| 7 | Electrical requirements ..... | 4 | +| 7.1 | Sparkover voltages (see clause 8.1)..... | 4 | +| 7.2 | Insulation resistance (see clause 8.2)..... | 6 | +| 7.3 | Capacitance..... | 6 | +| 7.4 | Transverse voltage..... | 6 | +| 7.5 | d.c. holdover voltages (see clause 8.5 and Figures 4 and 5) ..... | 6 | +| 7.6 | Life tests (see clause 8.6)..... | 7 | +| 7.7 | Short-circuit behaviour ..... | 8 | +| 8 | Test methods ..... | 8 | +| 8.1 | Sparkover voltage ..... | 8 | +| 8.2 | Insulation resistance ..... | 9 | +| 8.3 | Capacitance..... | 10 | +| 8.4 | Impulse transverse voltage for 3-electrode gas discharge tubes ..... | 10 | +| 8.5 | Holdover test ..... | 10 | +| 8.6 | Life tests ..... | 12 | +| 8.7 | Short-circuit test ..... | 13 | +| 9 | Environment tests ..... | 14 | +| 9.1 | Radiation..... | 14 | +| 9.2 | Robustness of terminations..... | 14 | +| 9.3 | Solderability ..... | 14 | +| 9.4 | Resistance to soldering heat ..... | 14 | +| 9.5 | Vibration..... | 14 | +| 9.6 | Damp heat cyclic ..... | 14 | +| 9.7 | Sealing ..... | 14 | +| 9.8 | Low temperature..... | 14 | +| 10 | Informative characteristics..... | 15 | +| 11 | Identification..... | 15 | +| 11.1 | Marking ..... | 15 | +| 11.2 | Documentation ..... | 15 | + +| | Page | +|-------------------------------------------------------------|------| +| 12    Ordering information ..... | 15 | +| Annex A – Test circuit for GDT used in ISDN circuits..... | 17 | +| Annex B – Sparkover test waveform ..... | 18 | +| Annex C – Determining the special test protector (STP)..... | 19 | + +# Recommendation ITU-T K.12 + +# Characteristics of gas discharge tubes for the protection of telecommunication installations + +# 1 Scope + +This Recommendation: + +- a) gives the characteristics of gas discharge tubes used in accordance with [b-ITU-T K.11] and [b-ITU-T K.46] for the protection of exchange and outdoor equipment, subscriber or customer equipment and telecommunication lines against overvoltages; +- b) deals with gas discharge tubes which have two or three electrodes; +- c) does not deal with mountings and their effect on tube characteristics (see [ITU-T K.65]); characteristics apply to gas discharge tubes as a component, mounted only in the ways described for the tests; +- d) does not deal with mechanical dimensions; +- e) does not deal with quality assurance requirements; and +- f) does not deal with gas discharge tubes which are connected to electrical power systems. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.65] Recommendation ITU-T K.65 (2011), *Overvoltage and overcurrent requirements for termination modules with contacts for test ports or surge protective devices*. +- [IEC 60060] IEC 60060-1:2010 and IEC 60060-2:2010, *High-voltage test techniques – Part 1: General definitions and test requirements and Part 2: Measuring systems*. +- [IEC 60068-2-1] IEC 60068-2-1:2007, *Environmental testing – Part 2-1: Tests – Test A: Cold*. +- [IEC 60068-2-6] IEC 60068-2-6:2007, *Environmental testing – Part 2-6: Tests – Test Fc: Vibration (sinusoidal)*. +- [IEC 60068-2-17] IEC 60068-2-17:2023, *Environmental testing – Part 2-17: Tests – Test Q: Sealing*. +- [IEC 60068-2-20] IEC 60068-2-20:2021, *Environmental testing – Part 2-20: Tests – Test Ta and Tb: Test methods for solderability and resistance to soldering heat of devices with leads*. +- [IEC 60068-2-21] IEC 60068-2-21:2021, *Environmental testing – Part 2-21: Tests – Test U: Robustness of terminations and integral mounting devices*. +- [IEC 60068-2-30] IEC 60068-2-30:2005, *Environmental testing – Part 2-30: Tests – Test Db: Damp heat, cyclic (12 h + 12 h cycle)*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +None. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 arc mode:** The lowest impedance or on-state of a gas discharge tube during normal operation (Figure 6). + +**3.2.2 arc voltage:** The voltage measured across the tube while in the lowest impedance state or arc mode (Figure 6). + +**3.2.3 breakdown:** See "sparkover". + +**3.2.4 current turn-off time:** The time required for the gas discharge tube to return itself to a non-conducting state following a period of conduction. + +**3.2.5 d.c. holdover voltage:** The maximum d.c. voltage across the terminals of a gas discharge tube under which it may be expected to clear and to return to the high impedance state after the passage of a surge, under specified circuit conditions. + +**3.2.6 destruction characteristic:** The relationship between the value of the discharge current and the time of flow until the gas discharge tube is mechanically destroyed (break, electrode short-circuit). For periods of time between 1 µs and some ms, it is based on impulse discharge currents, and for periods of time of 0.1 s and greater, it is based on alternating discharge currents. + +**3.2.7 discharge current:** The current that passes through a gas discharge tube when sparkover occurs. + +- **discharge current, alternating:** The r.m.s. value of an approximately sinusoidal alternating current passing through the gas discharge tube. +- **discharge current, impulse:** The peak value of the impulse current passing through the gas discharge tube. + +**3.2.8 discharge voltage:** The voltage that appears across the terminals of a gas discharge tube during the passage of discharge current. Note that residual voltage is also equivalent to discharge voltage. + +**3.2.9 gas discharge tube (GDT):** A gap, or several gaps, in an enclosed discharge medium, other than air at atmospheric pressure, designed to protect apparatus or personnel, or both, from high transient voltages; see clause 10 for the electrical characteristics of GDT also referred to as "gas tube surge arrester". + +**3.2.10 glow current:** The current which flows after sparkover when circuit impedance limits the discharge current to a value less than the glow-to-arc transition current. + +**3.2.11 glow mode:** This is a semi on-state in the area of the V/I curve where only a limited glow-current flows and the device has not yet turned on or reached the lowest impedance arc-mode (Figure 6). + +**3.2.12 glow voltage:** The peak value of the voltage drop across the GDT when a glow current is flowing. It is sometimes called the glow-mode voltage (Figure 6). + +- 3.2.13 glow-to-arc (transition) current:** The current required for the gas discharge tube to pass from the glow-mode into the arc mode. +- 3.2.14 impulse waveshape:** An impulse waveform designated as $x/y$ has a rise time of $x$ $\mu\text{s}$ and a decay time to half value of $y$ $\mu\text{s}$ as standardized in [IEC 60060]. +- 3.2.15 nominal alternating discharge current:** For currents with a frequency of 15 Hz to 62 Hz, the alternating discharge current which the gas discharge tube is designed to carry for a defined time. +- 3.2.16 nominal d.c. sparkover voltage:** The voltage specified by the manufacturer to designate the gas discharge tube (type designation) and to indicate its application with respect to the service conditions of the installation to be protected. Tolerance limits of the d.c. sparkover voltage are also referred to the nominal d.c. sparkover voltage. +- 3.2.17 nominal impulse discharge current:** The peak value of the impulse current with a defined waveshape with respect to time for which the gas discharge tube is rated. +- 3.2.18 residual voltage:** See "discharge voltage". +- 3.2.19 sparkover:** An electrical breakdown of the discharge gap of a gas discharge tube. Also referred to as "breakdown". +- 3.2.20 sparkover voltage:** The voltage which causes sparkover when applied across the terminals of a gas discharge tube (Figure 6). +- **sparkover voltage, d.c.:** The voltage at which the gas discharge tube sparks over when a slowly rising d.c. voltage up to 2 kV/s is applied. + - **sparkover voltage, impulse:** The highest voltage which appears across the terminals of a gas discharge tube in the period between the application of an impulse of a given waveshape and the time when current begins to flow. +- 3.2.21 transverse voltage:** For a gas discharge tube with several gaps, the difference of the discharge voltages of the gaps assigned to the two conductors of a telecommunication circuit during the passage of discharge current. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|-------------------------------------| +| GDT | Gas Discharge Tube | +| ISDN | Integrated Services Digital Network | +| xDSL | Digital Subscriber Line | + +# 5 Conventions + +None. + +# 6 Storage conditions + +Gas discharge tubes shall be capable of withstanding the following conditions without damage: + +- Temperature: $-40$ to $+70^{\circ}\text{C}$ ; +- Relative humidity: up to 95%. + +See also clauses 9.6 and 9.8 for environmental conditions. + +# 7 Electrical requirements + +Gas discharge tubes should have the following characteristics when tested in accordance with clause 8. Clauses 7.1 to 7.5 apply to virgin gas discharge tubes and also, where quoted in clause 7.6, to tubes subjected to life tests. + +NOTE – Using GDTs in circuits protecting certain systems can cause secondary effects like oscillations. This behaviour is dependent on certain circuit combinations like impedance and inductance in connection with certain GDT parameters like glow-to-arc transition current, etc. + +This phenomenon has not been studied adequately at this time and will be added to future work of ITU-T. + +## 7.1 Sparkover voltages (see clause 8.1) + +Sparkover voltages between the electrodes of a 2-electrode tube or between either line electrode and the earth electrode of a 3-electrode tube shall be within the limits in either Table 1a or Table 1b. + +NOTE 1 – For the definition of sparkover waveforms, see Annex B. + +Two types of GDT may be differentiated by their voltage nominal values. By employing special design techniques on either type, the disadvantages of the different technologies, to a certain extent, could be compensated for. + +The values for these types are given in tables 1a and 1b. Type 1 (Table 1a) represents the common type with a technology well suited for high current protection accomplished by a low glow voltage and arc voltage. Type 2 (Table 1b) represents the low impulse sparkover voltage type which has a faster response time, thus achieving lower impulse sparkover voltages with higher glow voltage and arc voltage, but offer lower current carrying capabilities. + +For 3-electrode tubes, the sparkover voltage between the line electrodes shall not be less than the minimum d.c. sparkover voltage in either Table 1a or Table 1b. It is recommended to achieve at least 1.2 times the minimum d.c. sparkover voltage given in either Table 1a or Table 1b. + +NOTE 2 – For 3-electrode GDTs, the maximum d.c. sparkover voltage a-b (line-line) may be restricted; a reasonable value is about 1.8-2.0 times the voltage a/b-c. + +### 7.1.1 Sparkover voltage values for type 1 GDT (common type) + +This type represents a technology well suited for high current protection accomplished by a low glow-voltage and arc-voltage (Table 1a). + +**Table 1a – Sparkover voltage values for common types of GDT** + +| Sparkover voltage | | | | | | | | | +|--------------------|-------------|----------|----------------------|----------|-----------------|--------------------------|-----------------|--------------------------| +| d.c. | | | | | Impulse | | | | +| | Initial (1) | | After life tests (2) | | at 100 V/μs | | at 1 000 V/μs | | +| | Min. (V) | Max. (V) | Min. (V) | Max. (V) | Initial (3) (V) | After life tests (4) (V) | Initial (5) (V) | After life tests (6) (V) | +| Nominal (V) | | | | | | | | | +| 90 | 72 | 108 | 65 | 120 | 450 | 550 | 500 | 600 | +| 150 | 120 | 180 | 110 | 195 | 500 | 600 | 600 | 700 | +| 200 | 160 | 240 | 150 | 250 | 600 | 700 | 700 | 800 | +| 230 | 184 | 280 | 170 | 300 | 600 | 700 | 700 | 800 | +| 250 | 200 | 300 | 180 | 325 | 600 | 700 | 700 | 800 | + +**Table 1a – Sparkover voltage values for common types of GDT** + +| Sparkover voltage | | | | | | | | | +|-------------------|-----|-----|-----|-----|---------|-------|-------|-------| +| d.c. | | | | | Impulse | | | | +| 350 | 280 | 420 | 260 | 455 | 900 | 1 000 | 1 000 | 1 100 | +| 420 | 360 | 520 | 360 | 550 | 1 000 | 1 100 | 1 100 | 1 200 | +| 500 | 400 | 600 | 400 | 650 | 1 100 | 1 200 | 1 200 | 1 300 | +| 600 | 480 | 720 | 450 | 780 | 1 300 | 1 400 | 1 400 | 1 500 | + +### **7.1.2 Sparkover voltage values for type 2 GDT (low impulse sparkover type)** + +This type (Table 1b) has a faster response time, thus achieving lower impulse sparkover voltages with higher glow-voltages and arc-voltages. Due to the design of this alternative type, the current capability according to Table 5 is, in general, much lower than for the comparable size of a common type GDT. + +Higher glow-voltage and arc-voltage in the gas discharge tube means higher power dissipation and thus reduction in class capability. + +It should be noted that there might be some restrictions on the availability of certain higher classes of Table 5 for some of the enhanced impulse voltage limits listed in Table 1b. + +**Table 1b – Sparkover voltage values for type 2 GDT (low impulse sparkover type)** + +| Sparkover voltage | | | | | | | | | +|--------------------|-----------------|-----------------|----------------------|-----------------|-----------------|--------------------------|-----------------|--------------------------| +| d.c. | | | | | Impulse | | | | +| | Initial (1) | | After life tests (2) | | at 100 V/μs | | at 1 000 V/μs | | +| | Min. (V) | Max. (V) | Min. (V) | Max. (V) | Initial (3) (V) | After life tests (4) (V) | Initial (5) (V) | After life tests (6) (V) | +| Nominal (V) | Min. (V) | Max. (V) | Min. (V) | Max. (V) | (V) | (V) | (V) | (V) | +| 200 | 160 | 240 | 150 | 250 | 350 | 450 | 450 | 550 | +| 230 | 184 | 280 | 170 | 300 | 400 | 500 | 450 | 550 | +| 350 | 265 | 455 | 265 | 600 | 700 | 800 | 800 | 900 | +| 420 | 360 | 520 | 360 | 650 | 750 | 900 | 850 | 1 000 | +| 500 | 400 | 600 | 400 | 700 | 800 | 950 | 900 | 1 050 | +| 600 | 480 | 720 | 420 | 800 | 900 | 1 100 | 1 000 | 1 200 | + +### **7.1.3 Sparkover voltage assessment** + +The sparkover voltages are characterized by a normal distribution assuming that a sufficient number of samples are tested. + +The sparkover voltages should be assessed with the criteria specified in Table 2, using the test methods specified in clause 8.1. + +**Table 2 – Sparkover voltage assessment method** + +| | Measured values initial | | +|---------------------------|---------------------------------------------------------------|--------------------------------------------------------------| +| | Probability of the measured values to be within the tolerance | Assessment expression | +| d.c. sparkover voltage | 99.7% | $U + 3S \leq \text{Maximum}$
$U - 3S \geq \text{Minimum}$ | +| Impulse sparkover voltage | 99.7% | $U + 3S \leq \text{Maximum}$
$U - 3S \geq \text{Minimum}$ | + +NOTE – U is the statistical average value of sparkover voltages. S is the standard deviation. + +## **7.2 Insulation resistance** (see clause 8.2) + +Not less than 1 G $\Omega$ initially. + +## **7.3 Capacitance** + +Typically, GDTs have a capacitance value of few pF, but not greater than 20 pF. + +## **7.4 Transverse voltage** + +The transverse voltage for a 3-electrode gas discharge tube is the difference in the discharge voltages between terminals a and b of the gaps assigned to the two conductors of the circuit during the passage of discharge current. For a 3-electrode gas discharge tube, the difference in time between the sparkover of the first and second gap shall not exceed 200 ns. + +## **7.5 d.c. holdover voltages** (see clause 8.5 and Figures 4 and 5) + +All types of tube shall have a current turn-off time less than 150 ms when subjected to one or more of the following tests according to the projected use. + +### **7.5.1 d.c. holdover test values for 2-electrode tubes** + +2-electrode tubes are tested in a circuit equivalent to that of Figure 4, where the test circuit components have the values given in Table 3. Gas discharge tubes with a nominal d.c. voltage of 230 V or higher shall be tested according to the test circuit shown in Annex A. + +**Table 3 – Holdover test values for 2-electrode tubes** + +| Component | Test 1 | Test 2 | Test 3 | +|-----------|--------------|--------------|----------------| +| PS1 | 52 V | 80 V | 135 V | +| R3 | 200 $\Omega$ | 330 $\Omega$ | 1 300 $\Omega$ | +| R2 | (Note) | 150 $\Omega$ | 150 $\Omega$ | +| C1 | (Note) | 100 nF | 100 nF | + +NOTE – Components omitted in this test. + +### **7.5.2 d.c. holdover test values for 3-electrode tubes** + +3-electrode tubes are tested in a circuit equivalent to that of Figure 5, where components have the values given in Table 4. + +**Table 4 – Holdover test values for 3-electrode tubes** + +| Component | Test 1 | Test 2 | | Test 3 | | +|-------------|----------|--------|----------------|---------|----------------| +| PS1 | 52 V | 80 V | | 135 V | | +| PS2 | 0 V | 0 V | | 52 V | | +| R3 | 200 Ω | 330 Ω | | 1 300 Ω | | +| R2 | (Note 1) | 150 Ω | 272 Ω (Note 2) | 150 Ω | 272 Ω (Note 2) | +| C1 | (Note 1) | 100 nF | 43 nF (Note 2) | 100 nF | 43 nF (Note 2) | +| R4 (Note 3) | 136 Ω | 136 Ω | | 136 Ω | | +| C2 (Note 3) | 83 nF | 83 nF | | 83 nF | | + +NOTE 1 – Components omitted in this test. +NOTE 2 – Optional alternative. +NOTE 3 – Optional. + +## 7.6 Life tests (see clause 8.6) + +The currents specified in clause 7.6.1 for the appropriate nominal current rating of the tube shall be applied. After each current application, the gas discharge tube shall be capable of meeting the requirements of clause 7.6.2. On completion of the number of current applications specified, the tube shall be capable of meeting the requirements of clause 7.6.3. + +### 7.6.1 Test currents + +Gas discharge tubes shall be subjected to the currents of columns 1 to 5 of Table 5. For each life test new gas discharge tubes shall be used. + +**Table 5 – Life test current values** + +| Test number | Nominal alternating discharge current | Nominal impulse discharge current | | | | +|--------------|---------------------------------------|-----------------------------------|-------------------------|-------------|-------------| +| | 1 | 2 | 3 | 4 | 5 | +| Waveform | a.c. 50-60 Hz | 8/20 μs | 10/350 μs a) | 10/1 000 μs | 10/1 000 μs | +| Applications | 10 | 10 | 1 | 300 | 1 500 | +| Dimension | A rms | kA peak | kA peak | A peak | A peak | +| Class | | | | | | +| 1 | 2.5 | 2.5 | 0.5 | 50 | 10 | +| 2 | 5 | 5 | 1 | 100 | 10 | +| 3 | 10 | 10 | 2.5 | 100 | 10 | +| 4 | 20 | 10 | 4 | 100 | 10 | +| 5 | 20 | 20 | 4 | 200 | 10 | + +a) Different high-energy test waveforms exist in some countries and regions, for example, see [IEC 61643-21]. + +### 7.6.2 Requirements during life test + +Insulation resistance: not less than 100 MΩ. + +d.c. and impulse sparkover voltage: not more than the relevant value in columns 2, 4 and 6 of either Table 1a or Table 1b. + +### 7.6.3 Requirements after completion of life test + +Insulation resistance: not less than 100 M $\Omega$ . + +d.c. and impulse sparkover voltage: not more than the relevant value in columns 2, 4 and 6 of either Table 1a or Table 1b. + +NOTE – After the passage of an alternating or impulse current of a value much higher than that shown in Table 5, the electrical characteristics of the GDT may be severely altered or the GDT may be even destroyed. + +Two extreme situations may occur: + +- 1) The gas discharge tube vents and acts like an insulator and presents a higher dielectric strength than it had initially. +- 2) The gas discharge tube turns to a low resistance or even becomes a short circuit which does not allow normal operation of the telecommunication service. (This situation may be preferable from the point of view of fault detection, fault signalling, protection and maintenance.) + +Test methods and the relations between the value and duration of the destructive current are not detailed in this Recommendation, nor is the state of the element after destruction. Operators should cover their requirements in these respects in their own documentation. + +Holdover voltage: as in clause 7.5. + +## 7.7 Short-circuit behaviour + +A short-circuit mechanism is necessary for gas discharge tubes intended for use in telecommunication applications where an a.c. current can occur, flowing for an unpredictable time. + +Depending on the a.c. current flow, the short-circuit mechanism shall operate in sufficient time to prevent the gas discharge tube from being overheated. + +# 8 Test methods + +Gas discharge tubes shall be tested according to the methods described in clauses 8.1 to 8.7 and, in given cases, according to Figure A.1 (Test circuit for GDT for integrated services digital network (ISDN) or other telecommunication equipment using higher voltages or bitrates (xDSL)). + +## 8.1 Sparkover voltage + +For testing the initial values of a gas discharge tube, the gas discharge tube shall be placed in darkness for at least 24 hours immediately prior to testing and shall be tested in darkness. + +### 8.1.1 d.c. sparkover voltage + +The gas discharge tube shall be tested with a voltage which increases so slowly that the sparkover voltage is independent of the rate of rise of the applied voltage. Typically, a rate of rise of 100 V/s is used, but higher rates may be used if it can be shown that the sparkover voltage is thereby not significantly changed. The tolerances on the waveshape of the rising test voltage are indicated in Annex B. The voltage is measured across the open-circuited terminals of the generator. $U_{max}$ of Figure B.1 is any voltage greater than the maximum permitted d.c. sparkover voltage of the gas discharge tube. + +The test shall employ a suitable circuit such as that shown in Figure 1. A minimum of 3 seconds shall elapse between repetitions of the test, with either polarity, on the same gas discharge tube. + +![Circuit diagram for d.c. sparkover test. A variable voltage power supply (PS) is connected in series with a 51 kΩ resistor. This series combination is connected in parallel with a voltmeter (V) and a gas discharge tube (E). The voltmeter measures the voltage across the gas discharge tube. The reference label K.12(10)_F01 is shown below the circuit.](33ed1f9b27c7c21c797aa928b0f06851_img.jpg) + +Circuit diagram for d.c. sparkover test. A variable voltage power supply (PS) is connected in series with a 51 kΩ resistor. This series combination is connected in parallel with a voltmeter (V) and a gas discharge tube (E). The voltmeter measures the voltage across the gas discharge tube. The reference label K.12(10)\_F01 is shown below the circuit. + +PS Variable voltage power supply + +NOTE – Means shall be included to ensure that the gas discharge tube sparks over once only. + +**Figure 1 – Circuit for d.c. sparkover test** + +For 3-electrode tubes, the sparkover voltage between the line electrodes shall not be less than the minimum d.c. sparkover voltage in either Table 1a or Table 1b. + +Each pair of terminals of a 3-electrode gas discharge tube shall be tested separately with the other terminal unterminated. + +### 8.1.2 Impulse sparkover voltage + +The voltage waveform measured across the open circuit test terminals shall have a nominal rate of rise selected from Table 1a or Table 1b and shall be within the enclosed limits indicated in Figure B.1. Figure 2 shows a suggested arrangement for testing with a voltage impulse which has a nominal rate of rise of 1.0 kV/μs. + +A minimum of 3 seconds shall elapse between repetitions of the test, with either polarity, on the same gas discharge tube. + +Each pair of terminals of a 3-electrode gas discharge tube shall be tested separately with the other terminal unterminated. + +![Circuit diagram for impulse sparkover test. A 5 kV impulse source (represented by a battery symbol and 0.1 μF capacitor) is connected in series with a 1 kΩ resistor. This is followed by a parallel combination of a 10 MΩ resistor and a 5 nF capacitor. The output of this network is connected in series with a 50 Ω resistor, which is then connected to a gas discharge tube (E) and an oscilloscope. The reference label K.12(10)_F02 is shown below the circuit.](70de8885bd7de15723aaad5eb5c5febf_img.jpg) + +Circuit diagram for impulse sparkover test. A 5 kV impulse source (represented by a battery symbol and 0.1 μF capacitor) is connected in series with a 1 kΩ resistor. This is followed by a parallel combination of a 10 MΩ resistor and a 5 nF capacitor. The output of this network is connected in series with a 50 Ω resistor, which is then connected to a gas discharge tube (E) and an oscilloscope. The reference label K.12(10)\_F02 is shown below the circuit. + +**Figure 2 – Testing arrangement producing a voltage impulse which has a wavefront with a virtual steepness of 1 kV/μs (see clauses 7.1 and 8.3)** + +## 8.2 Insulation resistance + +The insulation resistance shall be measured from each terminal to every other terminal of the gas discharge tube (see clause 7.2). The measurement shall be made at an applied potential of at least 100 V or not more than 90% of the minimum permitted d.c. sparkover voltage. The measuring source shall be limited to a short-circuit current of less than 10 mA. Terminals of 3-electrode gas discharge tubes not involved in the measurement shall be left unterminated. + +## 8.3 Capacitance + +The capacitance shall be measured between each terminal and every other terminal of the gas discharge tube (see clause 7.3). In measurements involving 3-electrode gas discharge tubes, the terminal not being tested shall be connected to a ground plane in the measuring instrument. + +## 8.4 Impulse transverse voltage for 3-electrode gas discharge tubes + +The duration of the transverse voltage shall be measured while an impulse voltage that has a virtual steepness of an impulse wavefront of 1 kV/μs is applied simultaneously to both discharge gaps. Measurement may be made with an arrangement as indicated in Figure 3 (also see clause 7.4). The difference in time between the sparkover of the first gap and that of the second is specified in clause 7.4. + +![Circuit diagram for impulse transverse voltage test. A surge generator (SG) is connected to two resistors (R) in series. The first resistor is connected to the anode (A) of a gas discharge tube (GDT). The second resistor is connected to the cathode (C) of the GDT. The GDT is connected to an oscilloscope (OSC). The circuit is labeled K.12(24).](16152cf1d84aea10848758f51a91ff6a_img.jpg) + +OSC Oscilloscope +R Line impedance +SG Surge generator (see Figure 2) + +Circuit diagram for impulse transverse voltage test. A surge generator (SG) is connected to two resistors (R) in series. The first resistor is connected to the anode (A) of a gas discharge tube (GDT). The second resistor is connected to the cathode (C) of the GDT. The GDT is connected to an oscilloscope (OSC). The circuit is labeled K.12(24). + +Figure 3 – Circuit for impulse transverse voltage test (see clause 7.4) + +## 8.5 Holdover test + +### 8.5.1 2-electrode gas discharge tube + +Tests shall be conducted using the circuit of Figure 4 (see also clause 7.5). Values of PS1, R2, R3 and C1 shall be selected for each test condition from Table 3. The current from the surge generator shall have an impulse waveform of 100 A, 10/1000 μs measured through a short circuit replacing the gas discharge tube under test. The polarity of the impulse current through the gas discharge tube shall be the same as the current from PS1. The time for current turn-off shall be measured for each direction of current passage through the gas discharge tube. Three impulses shall be applied at not greater than 1-minute intervals and the current turn-off time measured for each impulse. + +![Circuit diagram for holdover test of a 2-electrode gas discharge tube. A surge generator (SG) is connected to an isolation gap (E1). The circuit includes a resistor R1 in series with the gap, followed by a parallel combination of a resistor R2 and a capacitor C1. This is followed by an isolation diode D1 and a resistor R3. A gas discharge tube (GDT) with electrodes A and C is connected in parallel across the output. An oscilloscope (OSC) and a constant voltage d.c. supply (PS1) are also connected across the output. The diagram is labeled K.12(24).](8fbdfc3d17fb1dae7b2d8f5a287fa9fc_img.jpg) + +Circuit diagram for holdover test of a 2-electrode gas discharge tube. A surge generator (SG) is connected to an isolation gap (E1). The circuit includes a resistor R1 in series with the gap, followed by a parallel combination of a resistor R2 and a capacitor C1. This is followed by an isolation diode D1 and a resistor R3. A gas discharge tube (GDT) with electrodes A and C is connected in parallel across the output. An oscilloscope (OSC) and a constant voltage d.c. supply (PS1) are also connected across the output. The diagram is labeled K.12(24). + +- D1 Isolation diode or other isolation device + E1 Isolation gap or equivalent device + OSC Oscilloscope + PS1 Constant voltage d.c. supply or battery + R1 Impulse current-limiting resistor or waveshaping network + R2, R3 See Table 3 + SG Surge generator, 100 A, 10/1 000 μs + +**Figure 4 – Circuit for holdover test of 2-electrode gas discharge tube (see clause 7.5.1)** + +### 8.5.2 3-electrode gas discharge tube + +Tests shall be conducted using the circuit of Figure 5. Values of circuit components shall be selected from Table 4. The simultaneous currents that are applied to the gaps of the gas discharge tube shall have impulse waveforms of 100 A /10/1000 μs per side or chamber, measured through a short circuit replacing the gas discharge tube under test. The polarity of the impulse current through the gas discharge tube shall be the same as the current from PS1 and PS2. + +![Circuit diagram for holdover test of a 3-electrode gas discharge tube. A surge generator (SG) is connected to an isolation gap (E1). The circuit features two symmetrical branches. The left branch contains a resistor R1, diodes D1 and D3, a capacitor C2, a power supply PS1, and a resistor R3. The right branch contains a resistor R1, diodes D2 and D4, a capacitor C2, a power supply PS2, and a resistor R3. A central gas discharge tube (GDT) with electrodes A, B, and C is connected. Electrode A is connected to a network of capacitors C1, C2 and resistors R2, R4. Electrode B is connected to a network of capacitors C1, C2 and resistors R2, R4. Electrode C is connected to a network of resistors R3, R4. A dual channel oscilloscope (OSC) is connected across the output. The diagram is labeled K.12(24).](33a8f3f01dfa8bce75d23017855a13c5_img.jpg) + +Circuit diagram for holdover test of a 3-electrode gas discharge tube. A surge generator (SG) is connected to an isolation gap (E1). The circuit features two symmetrical branches. The left branch contains a resistor R1, diodes D1 and D3, a capacitor C2, a power supply PS1, and a resistor R3. The right branch contains a resistor R1, diodes D2 and D4, a capacitor C2, a power supply PS2, and a resistor R3. A central gas discharge tube (GDT) with electrodes A, B, and C is connected. Electrode A is connected to a network of capacitors C1, C2 and resistors R2, R4. Electrode B is connected to a network of capacitors C1, C2 and resistors R2, R4. Electrode C is connected to a network of resistors R3, R4. A dual channel oscilloscope (OSC) is connected across the output. The diagram is labeled K.12(24). + +- C1, C2 See Table 4 + E1 Isolation gap or equivalent device + OSC Dual channel oscilloscope + PS1, PS2 Batteries or d.c. power supplies + R1 Impulse current-limiting resistors or wave-shaping networks + R2, R3, R4 See Table 4 + +NOTE 1 – The polarity of diodes D1 to D4 must be reversed when the polarity of the d.c. power supplies and surge generators is reversed. + +**Figure 5 – Circuit for holdover test of 3-electrode gas discharge tube (see clause 7.5.2)** + +For each test condition, measurement of the time to current turn-off shall be made for both polarities of the impulse current. Three impulses in each direction shall be applied at intervals not greater than 1 minute and the time to current turn-off measured for each impulse. + +## 8.6 Life tests + +New gas discharge tubes shall be used for each of the tests. + +A proposed type test procedure is given in Table 6. + +**Table 6 – Recommended sample sizes to be used for a.c. and impulse life tests** + +| Test | Sample size | Test performed in accordance with clause 7.6.1, Table 5, column | +|--------------|-------------|-----------------------------------------------------------------| +| a.c. life | 20 | 1 | +| Impulse life | 20 | 2 | +| Impulse life | 20 | 3 | +| Impulse life | 20 | 4 | +| Impulse life | 20 | 5 | + +Alternating respectively impulse currents shall be applied as specified in Table 5 for the relevant class of the tube. + +The time between applications should be such as to prevent thermal accumulation in the tube. + +DC and impulse sparkover tests shall be performed on gas discharge tubes which are subject to the life conditions specified in clause 7.6.1. In order to achieve a test procedure as close to real practice as possible, the test has to be carried out under daylight conditions. All other test details should comply according to clause 8.1. + +It is recommended that a minimum of four sparkover voltage measurements are performed on each sample, two in each polarity. + +Measured values after life test under consideration (5% failure rate accepted), compare either Table 1a or Table 1b values after life. + +### 8.6.1 a.c. life (see clause 7.6) + +The alternating currents shall be applied as specified in Table 5, column 1, for a duration of 1 second. + +The r.m.s. a.c. voltage of the current source shall exceed the maximum d.c. sparkover voltage of the gas discharge tube by not less than 50%. + +The specified a.c. discharge current and duration shall be measured with the gas discharge tube replaced with a short circuit. For 3-electrode gas discharge tubes, a.c. discharge currents each with the value specified in Table 5, column 1, shall be discharged simultaneously from each electrode to the common electrode. + +The gas discharge tube shall be tested after each passage of a.c. discharge current to determine its ability to satisfy the requirements of clause 7.6.2. + +On completion of the specified number of current applications, the tube shall be allowed to cool to an ambient temperature and tested for compliance with clause 7.6.3. + +### 8.6.2 Impulse discharge current 8/20 µs + +Half the specified number of tests shall be carried out with one polarity followed by half with the opposite polarity. Alternatively, half the tubes in a sample may be tested with one polarity and the other half with the opposite polarity. + +For 3-electrode gas discharge tubes, independent impulse currents each with the value specified in Table 5, column 2, shall be discharged simultaneously from each electrode to the common electrode. + +### 8.6.3 Impulse discharge current 10/350 μs + +This test shall be applied only one time. + +For 3-electrode gas discharge tubes, independent impulse currents each with the value specified in Table 5, column 3, shall be discharged simultaneously from each electrode to the common electrode. + +### 8.6.4 Impulse discharge current 10/1000 μs + +To carry out this test, one of the methods listed in Table 7, shall be applied. Methods 1 and 2 must be used together for testing 3-electrode gas discharge tubes by testing 50% of the sample lot with method 1 and the remaining 50% with method 2. + +Although these four methods apply the same number of discharges, their end results may not be the same. + +**Table 7 – Impulse discharge current test method** + +| Method | Number of applications
10/1 000 μs (50..200 A);
(see column 4 of Table 5) | Number of applications
10/1 000 μs (10 A);
(see column 5 of Table 5) | Polarity | +|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------|----------------------------------------------------------------------------|----------| +| 1 | 300 times | 1 500 times | | +| 2 | 300 times | 1 500 times | | +| 3 | 150 times + and 150 times – | 750 times + and 750 times – | | +| 4 | 300 times +/– | 1 500 times +/– | | +| NOTE – The test results can vary depending on the test methods 1-4. It should be stated which test method was used or tested as agreed upon by the user and manufacturer. | | | | + +The voltage of the source shall exceed the maximum impulse sparkover voltage of the gas discharge tube by not less than 50%. The specified impulse discharge current and waveform shall be measured with the gas discharge tube replaced with a short circuit. For 3-electrode gas discharge tubes, independent impulse currents, each with the value specified in Table 5, columns 4 and 5, shall be discharged simultaneously from each electrode to the common electrode. + +The gas discharge tube shall be tested after each passage of an impulse discharge current or at less frequent intervals if agreed between the manufacturer and the user to determine its ability to satisfy the requirements of clause 7.6.2. + +On completion of the specified number of impulse currents, the tube shall be allowed to cool to an ambient temperature and tested for compliance with clause 7.6.3. + +### 8.7 Short-circuit test + +New tubes shall be used and an a.c. current capable of activating the thermal overload shall be applied to the gas discharge tube. The short-circuit mechanism shall be operated after it is subjected to a given a.c. current and time. The proposed sample size to be used for short-circuit tests is five for each test condition. + +The values and duration should be specified by the manufacturer of the gas discharge tubes. + +The behaviour of the short-circuit mechanism is particularly influenced by the environmental conditions and the termination module. Therefore, it is necessary that the test procedure and the requirements be in detail arranged between the manufacturer and the user of gas discharge tubes. + +Rec. ITU-T K.12 (08/2024) 13 + +# **9 Environment tests** + +## **9.1 Radiation** + +Gas discharge tubes shall not contain radioactive material. + +## **9.2 Robustness of terminations** + +The user shall specify a suitable test from [IEC 60068-2-21], if applicable. + +## **9.3 Solderability** + +Soldering terminations shall meet the requirements of [IEC 60068-2-20], test Ta method 1. + +## **9.4 Resistance to soldering heat** + +Gas discharge tubes with soldering terminations shall be capable of withstanding [IEC 60068-2-20], test Tb method 1b. After recovery, the gas discharge tube shall be visually checked and show no signs of damage, and its d.c. sparkover shall be within the limits for that tube. + +## **9.5 Vibration** + +A gas discharge tube shall be capable of withstanding [IEC 60068-2-6], Environmental testing, Test Fc: Vibration (sinusoidal) 10-500 Hz, 0.15 mm displacement for 90 minutes without damage. The user may select a more severe test from this reference. At the end of the test, the tube shall show no signs of damage and shall meet the d.c. sparkover and insulation resistance requirements specified in clauses 7.1 and 7.2. + +## **9.6 Damp heat cyclic** + +A gas discharge tube shall be capable of withstanding [IEC 60068-2-30]. At the end of the test, the tube shall meet the insulation resistance requirement specified in clause 7.2. + +## **9.7 Sealing** + +A gas discharge tube shall be capable of passing [IEC 60068-2-17] Test Qk, severity 600 hours, for fine leaks. The fine leak rate shall be less than $10^{-7}$ bar cm3 s-1. Helium shall be used as the test gas. + +The tube shall then be capable of passing the coarse leak test Qc method 1. + +## **9.8 Low temperature** + +A gas discharge tube shall be capable of withstanding [IEC 60068-2-1] Test Aa. $-40^{\circ}\text{C}$ , duration 2 hours, without damage. At the end of the test, the tube must meet the d.c. and impulse sparkover requirements of clause 7.1. + +# 10 Informative characteristics + +![Figure 6: Electrical characteristics of GDT. The figure contains three graphs: 6a shows voltage (V) vs. time (t) with a dashed sinusoidal surge and a solid limiting curve; 6b shows current (i) vs. time (t) with a dashed sinusoidal surge and a solid limiting curve; 6c shows voltage (V) vs. current (i) with a solid hysteresis loop. Key voltage levels V_s, V_gl, V_a, and V_e are marked on the y-axis of 6c. Regions G (glow mode) and A (arc mode) are labeled on the curves in 6a and 6b.](f8630b0582d6e5b1d81f877880ef0dda_img.jpg) + +$V_s$ Spark-over voltage + $V_{gl}$ Glow voltage + $V_a$ Arc voltage + $V_e$ Extinction voltage + G Glow mode range + A Arc mode range + +Figure 6: Electrical characteristics of GDT. The figure contains three graphs: 6a shows voltage (V) vs. time (t) with a dashed sinusoidal surge and a solid limiting curve; 6b shows current (i) vs. time (t) with a dashed sinusoidal surge and a solid limiting curve; 6c shows voltage (V) vs. current (i) with a solid hysteresis loop. Key voltage levels V\_s, V\_gl, V\_a, and V\_e are marked on the y-axis of 6c. Regions G (glow mode) and A (arc mode) are labeled on the curves in 6a and 6b. + +NOTE 1 – Graph 6a shows voltage at the GDT as a function of time when limiting a sinusoidal voltage surge. + +NOTE 2 – Graph 6b shows current at the GDT as a function of time when limiting a sinusoidal voltage surge. + +NOTE 3 – Graph 6c shows the voltage/current characteristic of the GDT obtained by combining the graphs of voltage and current. + +K.12(10)\_F6 + +6a – Voltage at the GDT as a function of time when limiting a sinusoidal voltage surge + +6b – Current at the GDT as a function of time when limiting a sinusoidal voltage surge + +6c – V/I characteristic of the GDT obtained by combining the graphs of voltage and current + +**Figure 6 – Electrical characteristics of GDT** + +# 11 Identification + +## 11.1 Marking + +Legible and permanent marking shall be applied to the tube, as necessary, to ensure that the user can determine the following information by inspection: + +- manufacturer; +- year of manufacture; +- code. + +The user may specify the codes to be used for this marking. + +## 11.2 Documentation + +Documents shall be provided to the user so that from the information in clause 11.1 he or she can determine the following further information: + +- full characteristics as set out in this Recommendation; +- statement that no radioactive material has been used. + +# 12 Ordering information + +The following information should be supplied by the user: + +- a) drawing giving all dimensions, finishes and termination details (including numbers of electrodes and identifying the earth electrode); +- b) nominal d.c. sparkover voltage, chosen from clause 7.1.1; +- c) nominal current rating chosen from clause 7.6.1; +- d) holdover voltage tests required in clause 7.5; +- e) marking codes required for clause 11.1; +- f) robustness of terminations – test required for clause 9.2; +- g) destruction characteristic, if required, including failure mode (see Note in clause 7.6.3); +- h) short-circuit mechanism; +- i) quality assurance requirements. + +# Annex A + +## Test circuit for GDT used in ISDN circuits + +(This annex forms an integral part of this Recommendation.) + +![Circuit diagram and graph for GDT testing in ISDN circuits. The circuit includes a surge generator, resistors R1 and R2, a diode, a capacitor, and a 135 V power supply. The graph shows voltage (U) vs current (I) with various test curves.](a289b64f80c6df506c0c55d553fc4496_img.jpg) + +The figure illustrates the test circuit and operating conditions for a GDT in ISDN circuits. The circuit diagram shows a surge generator connected to a series combination of a resistor $R_1$ and a diode. This is followed by a parallel combination of a resistor $R_2$ (150 $\Omega$ ) and a capacitor (100 nF). A second diode and resistor $R_2$ (450 $\Omega$ ) are connected in series with a 135 V power supply that has an automatic current limiter of 80 mA. A variable current source is also shown in parallel with the capacitor. + +The graph plots voltage $U$ (V) on the y-axis (0 to 200) against current $I$ (mA) on the x-axis (0 to 300). Key features include: + + +- A shaded region labeled "ISDN" between 0 and 70 mA, with a top boundary at 100 V. +- A dashed line labeled "Test curve for ISDN" starting at 135 V, 0 mA, and ending at 97 V, 80 mA. +- A solid line labeled "Test 2 according to Table 3" starting at 80 V, 0 mA and ending at 240 V, 0 mA. +- A solid line labeled "Test 3 according to Table 3" starting at 135 V, 0 mA and ending at 100 V, 0 mA. + +Reference: K.12(10)\_FA.1 + +Circuit diagram and graph for GDT testing in ISDN circuits. The circuit includes a surge generator, resistors R1 and R2, a diode, a capacitor, and a 135 V power supply. The graph shows voltage (U) vs current (I) with various test curves. + +Figure A.1 – Test circuit for GDT used in ISDN circuits + +# Annex B + +## Sparkover test waveform + +(This annex forms an integral part of this Recommendation.) + +The use of Figure B.1: + +A single mask will do for all values of $U_{max}$ and the nominal rate of rise, provided that it is a suitable size for the display of the waveform and that the scales of $U$ and $T$ of the waveform can be adjusted. This follows because the Y-axis has arbitrary points marked 0 and $U_{max}$ with $0.2 U_{max}$ at the appropriate point between them, while the X-axis has arbitrary points marked 0 and $T_2$ with $T_1 (= 0.2 T_2)$ , $0.9 T_1$ , $1.1 T_1$ , $0.9 T_2$ , $1.1 T_2$ marked at the appropriate points. The X and Y zeros need not coincide and, in fact, need not be shown at all. + +![Figure B.1: Sparkover test waveform graph showing voltage V vs time T with a shaded limit region defined by nominal rate of rise lines.](b6bd6d8ee5821226bc79251ca5937e07_img.jpg) + +The figure is a graph with Voltage (V) on the vertical axis and Time (T) on the horizontal axis. The vertical axis has markings for $0$ , $0.2 U_{max}$ , and $U_{max}$ . The horizontal axis has markings for $0$ , $0.9 T_1$ , $T_1$ , $1.1 T_1$ , $0.9 T_2$ , $T_2$ , and $1.1 T_2$ . A shaded region labeled 'Limit' is bounded by two parallel lines representing the 'Nominal rate of rise'. One boundary line passes through $(T_1, 0.2 U_{max})$ and $(T_2, U_{max})$ . The other boundary line is shifted horizontally, passing through $(0.9 T_1, 0.2 U_{max})$ and $(1.1 T_2, U_{max})$ . + +Figure B.1: Sparkover test waveform graph showing voltage V vs time T with a shaded limit region defined by nominal rate of rise lines. + +NOTE – Sparkover test waveform (non-conducting) must be within enclosed limits. + +K.12(24) + +**Figure B.1 – Sparkover test waveform** + +To compare a waveform trace with the mask, it is necessary to know the values of $U_{max}$ and the nominal rate of rise for the waveform in question. As an example, consider a waveform with $U_{max} = 750$ V and nominal rate of rise = 100 V/s: + +Then $0.2 U_{max} = 150$ V, $T_2 = 7.5$ s, $T_1 = 1.5$ s. + +Hold the mask against the trace and adjust the vertical scale so that the 150 V calibration is against $0.2 U_{max}$ and the 750 V point against $U_{max}$ . Adjust the horizontal scale similarly for 1.5 s = $T_1$ and 7.5 s = $T_2$ . Slide the mask so that the 150 V point on the trace is within the bottom boundary of the test window; the remainder of the trace up to 750 V must be within the test window. + +# Annex C + +## Determining the special test protector (STP) + +(This annex forms an integral part of this Recommendation.) + +### Selection of the primary protector + +A test house or laboratory needs to be given the characteristics of the "agreed" primary protector, for the equipment under test, so that they can select the special test protector. It is important that the "agreed" primary protector and special test protector characteristics determined and used at resistibility testing, be recorded in the test report\*. This may prevent an additional compliance test from having to be performed. + +The characteristics of the special test protector are determined by the "agreed" primary protector. Unfortunately, there are many types of primary protector available. This Recommendation lists the many nominal d.c. firing voltages and other characteristics for GDTs. Furthermore, the network operator may require a change of one of the characteristics in this Recommendation because of an agreement with a manufacturer. There are at least four reasons for the range of primary protectors used, and some of these are: + +- The network operator has a specific requirement, e.g., minimum d.c. firing voltage to prevent ring trip or the use of a specific termination module. [ITU-T K.65] may limit the range of GDTs which can be used. +- The manufacturer may specify a maximum d.c. and a maximum impulse firing voltage to coordinate with their equipment. +- The administration may specify a minimum d.c. firing voltage to prevent operation due to 230 V a.c. for safety reasons. +- The environment, predominantly a.c. or lightning surges, may also limit the characteristics of the GDT. + +The end result is an agreed primary protector. The characteristics of the agreed primary protector must be known to determine the characteristics of the special test protector. An equipment manufacturer needs to balance market opportunities (design the equipment to coordinate with the worst-case GDT) with design costs (design for the best case GDT). It should be noted that the term "worst case" does not indicate a poor quality GDT. GDTs may have a high firing voltage for many reasons, e.g., the GDT has to operate in an environment where a.c. surges predominate or the operator requires a high minimum d.c. firing voltage. A list of typical protection points and likely GDT used is given in Table C.1. + +NOTE – The specification of an agreed primary protector and special test protector used in resistibility test for products sold on the general market shall be determined based on complying to the rule or regulation for the networks to be connected. The manufacturer of equipment shall provide the specification of the agreed primary protector and special test protector to the user or installer of the equipment. + +**Table C.1 – Typical GDT application for equipment connected to external cables and for plant** + +| Application | Standard GDTs (Type 1)
Table 1a

(Characteristics are better suited for withstanding a.c. currents) | | Low impulse voltage GDTs (Type 2)
Table 1b

(May not be suitable when a.c. surges predominate) | | +|---------------------------------------------------|----------------------------------------------------------------------------------------------------------------------|----------------------------------|-----------------------------------------------------------------------------------------------------------------|----------------------------------| +| | d.c.
(V) | Impulse at 1kV/μs
(V) | d.c.
(V) | Impulse at 1kV/μs
(V) | +| Line cards, data circuits (nominally a 230 V GDT) | max. 300 | max. 800 | max. 300 | max. 550 | +| RFT circuits (nominally a 350 V GDT) | max. 455 | max. 1 100 | max. 600 | max. 900 | +| Customer premises (nominally a 600 V GDT) | max. 780 | max. 1 500 | max. 800 | max. 1 200 | +| Cable protection (nominally a 600 V GDT) | max. 780 | max. 1 500 | max. 800 | max. 1 200 | + +To assist those manufacturers who wish to design for, or test for, a worst-case GDT, a table of protection purposes and a typical worst-case GDT is provided in Table C.2. These values are based on this Recommendation. + +**Table C.2 – Worst-case GDT voltages** + +| Application | Worst-case GDT firing
(voltages taken from tables 1a and 1b) | | +|---------------------------------------------------|-------------------------------------------------------------------------|-----------------------------------| +| | d.c.
(V) | Impulse at 1 kV/μs
(V) | +| Line cards, data circuits (nominally a 230 V GDT) | max. 300 | max. 800 | +| RFT circuits (nominally a 350 V GDT) | max. 600 | max. 1 100 | +| Customer premises (nominally a 600 V GDT) | max. 800 | max. 1 500 | +| Cable protection (nominally a 600 V GDT) | max. 800 | max. 1 500 | + +NOTE – The values in this table are given to assist manufacturers to determine a worst-case "agreed" primary protector for design and testing purposes. Use of these values does not guarantee compliance with the product recommendations for every application in every country. ITU-T will update these values when feedback is received. + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.126-201707-I_PDF-E/raw.md b/marked/K/T-REC-K.126-201707-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..348cb6dd6c96a19fb4ec32865451121879cd6a3f --- /dev/null +++ b/marked/K/T-REC-K.126-201707-I_PDF-E/raw.md @@ -0,0 +1,1032 @@ + + +I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n + +# **ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +# **K.126** + +(07/2017) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +# --- **Surge protective component application guide – High frequency signal isolation transformers** + +Recommendation ITU-T K.126 + +![ITU logo](6ed175c791b5e156d9c98a8dbcc3318c_img.jpg) + +ITU logo + + + +## Recommendation ITU-T K.126 + +# Surge protective component application guide – High frequency signal isolation transformers + +## Summary + +Failures of Ethernet local area network (LAN) ports have been attributed to the use of inappropriate surge protective devices (SPDs), lack of insulation coordination and inappropriate wiring, which causes the failure of transformers, associated wiring, components and connectors. Recommendation ITU-T K.126 discusses isolation transformer parameters and how they influence the equipment common-mode and differential-mode surge performance. Access to the full text of Recommendation ITU-T K.95 is necessary to fully understand this Recommendation. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.126 | 2017-07-29 | 5 | 11.1002/1000/13280 | + +## Keywords + +Characteristics, common-mode surge, differential-mode surge, Ethernet, high frequency, isolation transformer, power over Ethernet, PoE, ratings, surge protective device, SPD. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2017 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|-----|-------------------------------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 3.1 | Terms defined elsewhere ..... | 1 | +| 3.2 | Terms defined in this Recommendation..... | 2 | +| 4 | Abbreviations and acronyms ..... | 3 | +| 5 | Conventions ..... | 3 | +| 6 | Component construction..... | 4 | +| 6.1 | Transformer basics ..... | 4 | +| 6.2 | Transformer parasitics ..... | 4 | +| 6.3 | Transformer core saturation ..... | 5 | +| 6.4 | High frequency signal transformers ..... | 6 | +| 7 | Characteristics..... | 8 | +| 7.1 | Measurement ..... | 8 | +| 7.2 | Inter-winding capacitance ..... | 8 | +| 7.3 | Insulation resistance ..... | 9 | +| 7.4 | Core saturation voltage–time value ..... | 10 | +| 7.5 | Winding resistance ..... | 11 | +| 7.6 | Saturated core secondary winding inductance ..... | 11 | +| 8 | Ratings ..... | 12 | +| 8.1 | Verification..... | 12 | +| 8.2 | Rated impulse voltage ..... | 12 | +| 8.3 | Rated winding d.c. .... | 13 | +| 9 | Application examples ..... | 14 | +| 9.1 | Transformer example..... | 14 | +| 9.2 | Common-mode surge ..... | 14 | +| 9.3 | DC insulation resistance ..... | 17 | +| 9.4 | Differential-mode primary winding surge..... | 18 | +| 9.5 | Rated impulse voltage ..... | 23 | +| 9.6 | Rated winding d.c. .... | 24 | +| | Annex A – Use of isolating transformers for a.c. power and signal applications..... | 25 | +| A.1 | Application of LITs to equipment that requires isolation ..... | 25 | +| A.2 | Application of LITs on communication line for high-speed signal transmission..... | 25 | +| A.3 | LITs for equipment with low resistibility..... | 26 | +| | Bibliography..... | 27 | + + + +## Recommendation ITU-T K.126 + +# Surge protective component application guide – High frequency signal isolation transformers + +# 1 Scope + +The [b-ITU-T K.96] application overview guide and other ITU-T component specific guide Recommendations cover surge protective components (SPCs) used in power and telecom surge protective devices (SPDs) and equipment ports. This application guide on high frequency signal isolation transformer technology SPCs covers: + +- component construction; +- characteristics; +- ratings; +- application examples. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T K.95] Recommendation ITU-T K.95 (2016), *Surge parameters of isolating transformers used in telecommunication devices and equipment*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 clearance** [b-IEC/TR 60664-2-1]: Shortest distance in air between two conductive parts. + +**3.1.2 common-mode surge** [ITU-T K.95]: Surge appearing equally on all conductors of a group at a given location. + +NOTE 1 – The reference point for common-mode surge voltage measurement can be a chassis terminal, or a local earth/ground point. + +NOTE 2 –Also known as longitudinal surge or asymmetrical surge. + +**3.1.3 creepage distance** [b-IEC/TR 60664-2-1]: Shortest distance along the surface of a solid insulating material between two conductive parts. + +**3.1.4 designation of an impulse shape** [b-IEC 60099-4]: Combination of two numbers, the first representing the virtual front time (T1) and the second the virtual time to half-value on the tail (T2). + +NOTE 1 – It is written as T1/T2, both in microseconds, the sign "/" having no mathematical meaning. + +NOTE 2 – Some standards use alternative designations such as A/B or $T1 \times T2$ . + +NOTE 3 – Combination wave generators have both voltage and current impulse designations given separated by a hyphen e.g., 1.2/50-8/20. + +NOTE 4 – Waveshapes defined as maximum front time and minimum time to half value are expressed as $T2$ . + +**3.1.5 differential-mode surge** [ITU-T K.95]: Surge occurring between any two conductors or two groups of conductors at a given location. + +NOTE 1 –The surge source may be floating, without a reference point or connected to reference point, such as a chassis terminal, or a local earth/ground point. + +NOTE 2 – Also known as metallic surge or transverse surge or symmetrical surge or normal surge. + +**3.1.6 electric screen** [b-IEC 60050-151]: Screen of conductive material intended to reduce the penetration of an electric field into a given region. + +**3.1.7 impulse withstand voltage** [b-IEC/TR 60664-2-1]: Highest peak value of impulse voltage of prescribed form and polarity which does not cause breakdown of insulation under specified conditions. + +**3.1.8 insulation coordination** [b-IEC/TR 60664-2-1]: Mutual correlation of insulation characteristics of electrical equipment taking into account the expected micro-environment and other influencing stresses. + +**3.1.9 insulation resistance** [b-IEC 62631-1]: Resistance under specified conditions between two conductive bodies separated by the insulating material. + +**3.1.10 isolating transformer** [b-IEC 60065]: Transformer with protective separation between the input and output windings. + +**3.1.11 rated impulse voltage** [b-IEC/TR 60664-2-1]: Impulse withstand voltage value assigned by the manufacturer to the equipment or to a part of it, characterizing the specified withstand capability of its insulation against transient overvoltages. + +**3.1.12 rated winding d.c.** [ITU-T K.95]: Maximum winding current that will not cause the winding conductor temperature to exceed a specified increase above the ambient temperature. + +**3.1.13 surge** [ITU-T K.95]: Temporary disturbance on the conductors of an electrical service caused by an electrical event not related to the service. + +**3.1.14 virtual front time; T1**: The front time T1 of a voltage impulse is $1/0.6$ times the interval T between the instants when the impulse is 30% and 90% of the peak value [b-IEC 60060-1]. The front time T1 of a surge current impulse is 1.25 times the interval T between the instants when the impulse is 10% and 90% of the peak value [b-IEC 62475]. + +NOTE – Some standards use the 10% and 90% front time measurement for the voltage impulse. + +**3.1.15 virtual origin; O1**: For the impulse voltage waveform, it is the instant at which a straight line drawn through the 30% and 90% amplitude values crosses the time axis [b-IEC 60060-1]. For the impulse current waveform, it is the instant at which a straight line drawn through the 10% and 90% amplitude values crosses the time axis [b-IEC 60060-1]. + +**3.1.16 virtual time to half-value; T2** [b-IEC 60060-1][b-IEC 62475]: Interval of time between the instant of virtual origin O1 and the instant when the voltage or current has decreased to half the peak value. + +**3.1.17 withstand voltage** [b-IEC/TR 60664-2-1]: Voltage to be applied to a specimen under prescribed test conditions which does not cause breakdown and/or flashover of a satisfactory specimen. + +## **3.2 Terms defined in this Recommendation** + +None. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|---------------------------------| +| DMM | Digital multimeter | +| GDT | Gas Discharge Tube | +| IR | Insulation Resistance | +| LAN | Local Area Network | +| LIT | Lightning Isolation Transformer | +| PoE | Power over Ethernet | +| POTS | Plain Old Telephone System | +| RJ45 | Registered Jack 45 | +| SPC | Surge Protective Component | +| SPD | Surge Protective Device | + +# 5 Conventions + +This Recommendation uses the following: + +[b-IEC 60617] Type 1 symbols to represent the different transformer configurations. + +Figure 5-1 shows the symbol for a two-winding transformer. + +![Symbol for a two-winding transformer](0b87abe67b21a93777287649c33e755d_img.jpg) + +The diagram shows the standard symbol for a two-winding transformer. It consists of two vertical, facing semi-circular coils. Each coil has four loops. The top and bottom terminals of each coil are connected to horizontal lines that extend outwards to small open circles. Below the diagram is the text 'K.126(17)\_F5-1'. + +Symbol for a two-winding transformer + +**Figure 5-1 – Symbol for a two-winding transformer** + +Figure 5-2 shows the symbol for a two-winding transformer with instantaneous voltage polarity indicators. + +![Symbol for a two-winding transformer with polarity indication](99bae07626f60f9ede10e2e387ef7051_img.jpg) + +The diagram shows the symbol for a two-winding transformer with polarity indication. It is identical to the symbol in Figure 5-1, but with a solid black dot placed above the top terminal of each coil. Below the diagram is the text 'K.126(17)\_F5-2'. + +Symbol for a two-winding transformer with polarity indication + +**Figure 5-2 – Symbol for a two-winding transformer with polarity indication** + +Figure 5-3 shows the symbol for a two-winding transformer with an electric screen between the windings. + +![Symbol for a two-winding transformer with electric screen. It shows two overlapping semi-circular coils facing each other, separated by a vertical dashed line representing the electric screen. There are four terminals: two on the left for the primary and two on the right for the secondary. A label 'K.126(17)_F5-3' is at the bottom right.](a5ee5c23b6dc52ec1d724b76d5a5f58f_img.jpg) + +Symbol for a two-winding transformer with electric screen. It shows two overlapping semi-circular coils facing each other, separated by a vertical dashed line representing the electric screen. There are four terminals: two on the left for the primary and two on the right for the secondary. A label 'K.126(17)\_F5-3' is at the bottom right. + +**Figure 5-3 – Symbol for a two-winding transformer with electric screen** + +Figure 5-4 shows the symbol for a transformer with centre-tapped windings. When testing is done with shorted windings, the centre tap is also connected to that winding shorting link, other testing is done without any connection to the centre tap terminal. + +![Symbol for a transformer with centre-tapped windings. It shows two overlapping semi-circular coils with a central tap on each. The primary has three terminals on the left, and the secondary has three terminals on the right. The central taps are labeled 'CT'. A label 'K.126(17)_F5-4' is at the bottom right.](e6df2733626a85205c1db682e6259c46_img.jpg) + +Symbol for a transformer with centre-tapped windings. It shows two overlapping semi-circular coils with a central tap on each. The primary has three terminals on the left, and the secondary has three terminals on the right. The central taps are labeled 'CT'. A label 'K.126(17)\_F5-4' is at the bottom right. + +**Figure 5-4 – Transformer with centre-tapped windings** + +# 6 Component construction + +## 6.1 Transformer basics + +The ideal transformer transforms the primary winding voltage, $V_P$ , to a secondary winding voltage of $V_S$ . The relationship is $V_S = V_P/n$ , where $n$ is the primary to secondary turns ratio. + +Similarly the primary winding current, $I_P$ , transforms to a secondary winding current of $I_S$ . The relationship is $I_S = I_P * n$ . The transformer is 100 % efficient with a primary power of $V_P * I_P$ and a secondary power of $V_S * I_S = (V_P/n) * (I_P * n) = V_P * I_P$ . The transformer winding inductance is considered to be high enough that it does not adversely affect the circuit operation. Figure 6-1 shows the ideal transformer. + +![Symbol for an ideal transformer. It shows two overlapping semi-circular coils. The primary is labeled with voltage V_P and current I_P. The secondary is labeled with voltage V_S and current I_S. The turns ratio is labeled 'n'. A label 'K.126(17)_F6-1' is at the bottom right.](1eadbbe42cfcac5c0023577110aec5e3_img.jpg) + +Symbol for an ideal transformer. It shows two overlapping semi-circular coils. The primary is labeled with voltage V\_P and current I\_P. The secondary is labeled with voltage V\_S and current I\_S. The turns ratio is labeled 'n'. A label 'K.126(17)\_F6-1' is at the bottom right. + +| | | | | +|-------|----------------------------------------------|-------|---------------------------| +| $V_P$ | Primary winding voltage | $I_P$ | Primary winding current | +| $V_S$ | Secondary winding voltage | $I_S$ | Secondary winding current | +| $n$ | Transformer primary to secondary turns ratio | | | + +**Figure 6-1 – Ideal transformer** + +## 6.2 Transformer parasitics + +The primary winding and secondary winding will not be perfectly coupled and the non-coupled inductance is called leakage inductance. Circuit-wise winding leakage inductance can be emulated by adding a series inductor, $L_{LP}$ , to the primary winding and adding a series inductor, $L_{LS}$ , to the + +secondary winding. (In circuit simulation, an alternative is to make the winding coupling factor, $k$ , less than one.) + +Neither will the windings have zero resistance. Winding resistance is emulated by adding a series resistor, $R_p$ , to the primary winding and a series resistor, $R_s$ , to the secondary winding. + +The primary winding will not have infinite inductance and is represented by the inductor, $L_p$ , which transforms to a secondary inductor of $L_s = L_p/n^2$ . Inductor, $L_p$ , is effectively in parallel with the primary winding of the ideal transformer. Figure 6-2 shows the equivalent circuit with the parasitics. Example values are shown in Table 1. + +![Figure 6-2: Equivalent circuit diagram of an ideal transformer with parasitics. The primary side (left) shows a series combination of a resistor R_p and an inductor L_LP, which is then in parallel with an inductor L_p. This is connected to the primary winding of an ideal transformer with turns ratio n. The secondary side (right) shows the secondary winding connected to a series combination of an inductor L_LS and a resistor R_s. The diagram is labeled 'Primary', 'Secondary', and 'K.126(17)_F6-2'.](5a4e62bead259c258d069fd3663ea670_img.jpg) + +Figure 6-2: Equivalent circuit diagram of an ideal transformer with parasitics. The primary side (left) shows a series combination of a resistor R\_p and an inductor L\_LP, which is then in parallel with an inductor L\_p. This is connected to the primary winding of an ideal transformer with turns ratio n. The secondary side (right) shows the secondary winding connected to a series combination of an inductor L\_LS and a resistor R\_s. The diagram is labeled 'Primary', 'Secondary', and 'K.126(17)\_F6-2'. + +| | | | | +|----------|----------------------------------------------|----------|------------------------------------------------| +| $L_p$ | Primary winding self-inductance component | $L_s$ | Secondary winding self-inductance component | +| $L_{LP}$ | Primary winding leakage inductance component | $L_{LS}$ | Secondary winding leakage inductance component | +| $R_p$ | Primary winding resistance component | $R_s$ | Secondary winding resistance component | +| $n$ | Transformer primary to secondary turns ratio | | | + +**Figure 6-2 – Ideal transformer with winding leakage inductance, winding resistance and the actual primary self-inductance added** + +## 6.3 Transformer core saturation + +Without a core, the primary and secondary windings have a low inductance and poor coupling. Figure 6-3 shows how the two windings are effectively independent. Current through a winding creates a widely dispersed magnetic flux, $\Phi$ , in and around the winding, see Figure 6-3. + +![Figure 6-3: Diagram showing two separate, uncoupled windings. Each winding is shown as a series of loops with current I entering and magnetic flux Φ circulating within its own loops. The windings are not on a common core, illustrating independent flux paths. The diagram is labeled 'K.126(17)_F6-3'.](c78c2eefd86269d1740ab85a916f24f2_img.jpg) + +Figure 6-3: Diagram showing two separate, uncoupled windings. Each winding is shown as a series of loops with current I entering and magnetic flux Φ circulating within its own loops. The windings are not on a common core, illustrating independent flux paths. The diagram is labeled 'K.126(17)\_F6-3'. + +**Figure 6-3 – Transformer winding flux without a core in place** + +When the windings are on a magnetic core, the flux is strongly constrained to the core resulting in a good coupling between the windings and a higher winding inductance value, see Figure 6-4. + +![Diagram of a transformer core with a winding. A rectangular core is shown with a blue wire wound around it. An arrow labeled 'I' points into the core from the left, and an arrow labeled 'Φ' points out of the core to the right. The diagram is labeled K.126(17)_F6-4.](d4af765160d04ecef538e5066006dc77_img.jpg) + +K.126(17)\_F6-4 + +Diagram of a transformer core with a winding. A rectangular core is shown with a blue wire wound around it. An arrow labeled 'I' points into the core from the left, and an arrow labeled 'Φ' points out of the core to the right. The diagram is labeled K.126(17)\_F6-4. + +**Figure 6-4 – Transformer winding flux with a core in place** + +The general magnetic formula for winding inductance is $L = N \cdot \Phi / I_{\text{MAG}}$ , where $N$ is the number of turns of the winding, $\Phi$ is the winding flux and $I_{\text{MAG}}$ is the winding magnetizing current. The inductance $L$ is proportional to the flux to current ratio, $\Phi / I_{\text{MAG}}$ . The winding without a core has a constant $\Phi / I_{\text{MAG}}$ slope and the inductance value will be constant too, see Figure 6-5. The winding with a core has a high initial $\Phi / I_{\text{MAG}}$ slope that decreases rapidly in the winding saturation current, $I_{\text{MAGSAT}}$ , region and stabilizes to a low slope thereafter. The resultant inductance versus current characteristic will show a high initial inductance value, which decreases in the $I_{\text{MAGSAT}}$ region and stabilizes to a low value, as shown in Figure 6-5. + +![Graph of Inductance L versus Winding current I_MAG. The y-axis is labeled 'Inductance L' and the x-axis is labeled 'Winding current I_MAG'. A curve labeled 'Winding with core' starts at a high inductance value and drops sharply at a current labeled I_MAGSAT, then levels off at a low inductance value. A horizontal dashed line labeled 'Winding without core' represents a constant inductance value. The graph is labeled K.126(17)_F6-5.](42ff8b598a0818ca8b6ef30850ad5f4e_img.jpg) + +Graph of Inductance L versus Winding current I\_MAG. The y-axis is labeled 'Inductance L' and the x-axis is labeled 'Winding current I\_MAG'. A curve labeled 'Winding with core' starts at a high inductance value and drops sharply at a current labeled I\_MAGSAT, then levels off at a low inductance value. A horizontal dashed line labeled 'Winding without core' represents a constant inductance value. The graph is labeled K.126(17)\_F6-5. + +**Figure 6-5 – Winding inductance, $L$ , versus winding magnetizing current $I_{\text{MAG}}$** + +Although the saturation "knee" in the Figure 6-5 characteristic exists over a range of current, under fast-rising current surge conditions the inductance change accelerates the transition through the $I_{\text{MAGSAT}}$ region. This rapid transition makes it easy to determine when core saturation occurs, see Figure 9-10. + +Once the transformer core has saturated, the secondary circuit can be represented as a series circuit consisting of the secondary saturated winding inductance component, $L_{\text{SSAT}}$ , carrying the peak secondary current just prior to saturation, $I_{\text{SM}}$ , the secondary leakage inductance component, $L_{\text{LS}}$ and the secondary winding resistance component, $R_{\text{S}}$ . + +## 6.4 High frequency signal transformers + +Soft ferrites are often used for the cores of high frequency transformers. In depth details of soft ferrites and transformers using them can be found in [b-Snelling, 1988] and [b-Snelling, 1983]. + +To reduce the leakage inductance to a negligible level, the primary and secondary wires are often wound together on the core. This is called bifilar winding, which is defined as a set of two coils + +whose turns consist of two contiguous conductors isolated from one another. As the wires are in contact with each other, the wire insulation coating must be able to withstand the rated impulse voltage. The closeness of the two winding conductors increases the inter-winding capacitance and a value of about 25 pF is typical. + +Power over Ethernet (PoE) requires a primary winding centre-tap from which to extract the DC (direct current) power. Transformers for this purpose are often quadfilar wound, i.e., four wires are wrapped together, then wound on to the core. Pairs of windings can then be connected in series to give two centre-tapped windings as shown in Figure 6-6. + +![Figure 6-6: Quadfilar wound centre-tapped primary and secondary windings. The diagram shows a primary winding and a secondary winding, both with centre-taps. The primary winding is connected to a PoE feed, and the secondary winding is connected to a DC feed. The diagram is labeled K.126(17)_F6-6.](eefe19c5e14dc4d6c316b7f7fbb7d7d7_img.jpg) + +Figure 6-6: Quadfilar wound centre-tapped primary and secondary windings. The diagram shows a primary winding and a secondary winding, both with centre-taps. The primary winding is connected to a PoE feed, and the secondary winding is connected to a DC feed. The diagram is labeled K.126(17)\_F6-6. + +**Figure 6-6 – Quadfilar wound centre-tapped primary and secondary windings** + +Often common-mode chokes and Ethernet transformers are supplied as a complete assembly. Circuit examples of these are shown in Figure 6-7. Such assemblies combined with a registered jack 45 (RJ45) are also available, although some of these combined units have been found to have creepage and clearance problems [b-Ardley]. + +![Figure 6-7: Magnetic assembly circuits. The diagram shows two circuit examples. The top example shows a primary winding connected to an equipment port and a PoE feed, with a common-mode choke on the secondary side connected to TX/RX and DC feed. The bottom example shows a primary winding connected to an equipment port and a PoE feed, with a common-mode choke on the primary side connected to TX/RX. The diagram is labeled K.126(17)_F6-7.](410562339ce067fdc6fa41940c118658_img.jpg) + +Figure 6-7: Magnetic assembly circuits. The diagram shows two circuit examples. The top example shows a primary winding connected to an equipment port and a PoE feed, with a common-mode choke on the secondary side connected to TX/RX and DC feed. The bottom example shows a primary winding connected to an equipment port and a PoE feed, with a common-mode choke on the primary side connected to TX/RX. The diagram is labeled K.126(17)\_F6-7. + +**Figure 6-7 – Magnetic assembly circuits** + +Figure 6-8 illustrates a wound component assembly, the unpotted view showing four quadfilar wound Ethernet transformers with their smaller four bifilar wound common-mode chokes. + +![Figure 6-8 shows two views of a magnetic assembly for an Ethernet port. On the left is an unpotted assembly showing four toroidal transformers with copper wire windings mounted on a PCB inside a plastic frame. On the right is a potted assembly, which is a black rectangular surface-mount component with 16 gull-wing pins and the number '1515' printed on top next to a white polarity dot.](0dd5ee731e9d7e34e498b5c926110773_img.jpg) + +Figure 6-8 shows two views of a magnetic assembly for an Ethernet port. On the left is an unpotted assembly showing four toroidal transformers with copper wire windings mounted on a PCB inside a plastic frame. On the right is a potted assembly, which is a black rectangular surface-mount component with 16 gull-wing pins and the number '1515' printed on top next to a white polarity dot. + +**Figure 6-8 – Unpotted and potted magnetic assembly for one Ethernet port** + +(Figure 6-8 is reproduced with permission from Bourns, Inc.) + +# 7 Characteristics + +## 7.1 Measurement + +[ITU-T K.95] defines the test circuits and measurement procedures for the transformer parameters discussed in this clause. + +## 7.2 Inter-winding capacitance + +The value of the inter-winding capacitance value determines the level of capacitive current that flows into the secondary circuit as a result of primary voltage, $dV/dt$ . [ITU-T K.95] uses the circuit shown in Figure 7-1 to measure the total primary winding to secondary winding capacitance component, $C_{P-S}$ . For the purposes of circuit modelling, 50% of $C_{P-S}$ , can be considered as connected between the winding starts and the remaining 50% of $C_{P-S}$ , can be considered as connected between the winding ends. + +![Figure 7-1: Test circuit diagram. It shows two parallel vertical dashed rectangles representing windings Wp (left) and Ws (right). The top terminals of both windings are connected together to one side of a capacitance meter 'F'. The bottom terminals of both windings are connected together to the other side of the meter 'F'. A capacitor symbol labeled CP-S is shown connected between the centers of the two windings. The diagram is labeled K.126(17)_F7-1.](f6e8acf9f931452d01688d311b5c0364_img.jpg) + +Figure 7-1: Test circuit diagram. It shows two parallel vertical dashed rectangles representing windings Wp (left) and Ws (right). The top terminals of both windings are connected together to one side of a capacitance meter 'F'. The bottom terminals of both windings are connected together to the other side of the meter 'F'. A capacitor symbol labeled CP-S is shown connected between the centers of the two windings. The diagram is labeled K.126(17)\_F7-1. + +$W_p$ Primary winding      $C_{P-S}$ Primary to secondary capacitance + $W_s$ Secondary winding    $F$ Capacitance meter + +**Figure 7-1 – Test circuit to measure the transformer inter-winding capacitance** + +If the transformer has an electric screen between the primary and secondary windings, three capacitances need to be considered, the residual inter-winding capacitance component, $C_{P-S}$ , the primary to screen capacitance component, $C_{P-Screen}$ and the secondary winding to screen capacitance component, $C_{S-Screen}$ . [ITU-T K.95] uses the circuit shown in Figure 7-2 to measure these three capacitance values. + +![Figure 7-2: Test circuit to measure the inter-winding capacitance of a transformer with an electric screen. The diagram shows a primary winding (Wp) and a secondary winding (Ws) separated by an electric screen (ES). Capacitance measurement connections are shown: CH (Capacitance measurement connection Hi) connected to Wp, CL (Capacitance measurement connection Lo) connected to ES, and G (Guard connection) connected to Ws. The capacitance bridge (F) is connected between CH and CL. The circuit also includes capacitors CP-Screen, CS-Screen, and CP-S (Primary to secondary residual capacitance).](33ed1f9b27c7c21c797aa928b0f06851_img.jpg) + +Figure 7-2: Test circuit to measure the inter-winding capacitance of a transformer with an electric screen. The diagram shows a primary winding (Wp) and a secondary winding (Ws) separated by an electric screen (ES). Capacitance measurement connections are shown: CH (Capacitance measurement connection Hi) connected to Wp, CL (Capacitance measurement connection Lo) connected to ES, and G (Guard connection) connected to Ws. The capacitance bridge (F) is connected between CH and CL. The circuit also includes capacitors CP-Screen, CS-Screen, and CP-S (Primary to secondary residual capacitance). + +K.126(17)\_F7-2 + +| | | | | +|-------|---------------------------------------|----------------|-------------------------------------------| +| $W_p$ | Primary winding | $C_{P-Screen}$ | Primary to screen capacitance | +| $W_s$ | Secondary winding | $C_{S-Screen}$ | Secondary to screen capacitance | +| ES | Electric screen | $C_{P-S}$ | Primary to secondary residual capacitance | +| $C_H$ | Capacitance measurement connection Hi | G | Guard connection (coaxial cables screen) | +| $C_L$ | Capacitance measurement connection Lo | F | Guarded measurement capacitance bridge | + +**Figure 7-2 – Test circuit to measure the inter-winding capacitance of a transformer with an electric screen** + +The values of $C_{P-Screen}$ and $C_{S-Screen}$ can be measured by making the following connection changes in Figure 7-2: + +- For $C_{P-Screen}$ measurement, connect $C_H$ to $W^P$ , connect $C_L$ to ES, and connect G to $W_s$ . +- For $C_{S-Screen}$ measurement, connect $C_H$ to $W_s$ , connect $C_L$ to ES, and connect G to $W_p$ . + +## 7.3 Insulation resistance + +[b-IEEE 802.3] requires that the Ethernet port insulation resistance (IR) at 500 V d.c. be 2 M $\Omega$ or greater. [ITU-T K.95] uses the circuit shown in Figure 7-3 to measure the IR of a transformer. Both the primary winding, $W_p$ , and secondary winding, $W_s$ , are short-circuited. The IR is measured between the two short circuits. + +![Figure 7-3: Test circuit to measure the insulation resistance of a transformer. The diagram shows a primary winding (Wp) and a secondary winding (Ws) both short-circuited. An IR meter with defined dc bias (Ω) is connected between the two short circuits.](c67d21fb3d9042e88cdc669f071b4e7c_img.jpg) + +Figure 7-3: Test circuit to measure the insulation resistance of a transformer. The diagram shows a primary winding (Wp) and a secondary winding (Ws) both short-circuited. An IR meter with defined dc bias (Ω) is connected between the two short circuits. + +K.126(17)\_F7-3 + +| | | | | +|-------|-------------------|----------|-------------------------------| +| $W_p$ | Primary winding | $\Omega$ | IR meter with defined dc bias | +| $W_s$ | Secondary winding | | | + +**Figure 7-3 – Test circuit to measure the insulation resistance of a transformer** + +If the transformer has an electric screen between the primary and secondary windings, three IRs need to be considered, primary winding to screen, secondary winding to screen and primary to secondary. [ITU-T K.95] uses the circuit shown in Figure 7-4 to measure the IR to screen values. + +![Figure 7-4: Test circuit to measure the insulation resistance of a transformer with an electric screen. The diagram shows a transformer with primary winding Wp, secondary winding Ws, and an electric screen ES. A two-position selector switch (SW) is connected to the primary winding and an IR meter (Ω) with a defined dc bias. The secondary winding is connected to the electric screen and the IR meter.](fa859e4e468bfb2710a94527f2c504af_img.jpg) + +Figure 7-4: Test circuit to measure the insulation resistance of a transformer with an electric screen. The diagram shows a transformer with primary winding Wp, secondary winding Ws, and an electric screen ES. A two-position selector switch (SW) is connected to the primary winding and an IR meter (Ω) with a defined dc bias. The secondary winding is connected to the electric screen and the IR meter. + +$W_P$ Primary winding      $\Omega$ IR meter with defined dc bias + $W_S$ Secondary winding    SW Two position selector switch +ES Electric screen + +**Figure 7-4 – Test circuit to measure the insulation resistance of a transformer with an electric screen** + +## 7.4 Core saturation voltage–time value + +The value of the voltage–time integral, normally expressed in volt-seconds $V \cdot s$ , determines when the transformer core goes into saturation. [ITU-T K.95] uses the circuit shown in Figure 7-5 to measure the secondary voltage–time let-through. + +![Figure 7-5: Test circuit to measure the transformer voltage–time product. The diagram shows a transformer with primary winding Wp and secondary winding Ws. A pulse generator (G) with 50 Ω source impedance is connected to the primary winding. The secondary winding is connected to an oscilloscope (O) monitoring the peak secondary winding voltage Vs.](a83ba9e3e2c1e21dd69953a7b09e45b4_img.jpg) + +Figure 7-5: Test circuit to measure the transformer voltage–time product. The diagram shows a transformer with primary winding Wp and secondary winding Ws. A pulse generator (G) with 50 Ω source impedance is connected to the primary winding. The secondary winding is connected to an oscilloscope (O) monitoring the peak secondary winding voltage Vs. + +$W_P$ Primary winding      G Pulse generator, 50 $\Omega$ source impedance + $W_S$ Secondary winding    O Oscilloscope monitoring $V_S$ + $V_S$ Peak secondary winding voltage + +**Figure 7-5 – Test circuit to measure the transformer voltage–time product** + +Figure 7-6 shows the generator open-circuit output voltage and the resultant secondary winding voltage. Core saturation is shown by the secondary winding voltage pulse being truncated, having a shorter duration, $t_s$ , than the generator pulse. The transformer voltage–time product is given by $V_s t_s$ , expressed in microvolt seconds. How to use the volt second parameter is given in clause 9.4.4. + +![Figure 7-6: Generator and transformer secondary voltage waveforms. The top waveform shows a rectangular pulse with peak voltage V_G. The bottom waveform shows the secondary voltage V_S, which rises to a peak V_S and then decays. A horizontal dashed line at 0.5 V_S indicates the point where the voltage has decayed to half its peak value. The time interval from the start of the decay until it reaches 0.5 V_S is labeled t_S. The diagram is labeled K.126(17)_F7-6.](1d529a819ad929684331c55eed6673bb_img.jpg) + +Figure 7-6: Generator and transformer secondary voltage waveforms. The top waveform shows a rectangular pulse with peak voltage V\_G. The bottom waveform shows the secondary voltage V\_S, which rises to a peak V\_S and then decays. A horizontal dashed line at 0.5 V\_S indicates the point where the voltage has decayed to half its peak value. The time interval from the start of the decay until it reaches 0.5 V\_S is labeled t\_S. The diagram is labeled K.126(17)\_F7-6. + +$V_G$ Open-circuit pulse generator peak voltage    $t_S$ Secondary winding voltage time above 50% $V_S$ + $V_S$ Secondary winding peak voltage + +**Figure 7-6 – Generator and transformer secondary voltage waveforms** + +## 7.5 Winding resistance + +The value of the primary winding resistance component, $R_P$ , is important for PoE applications, since it represents a loss in delivered power. Generally the primary resistance balance of the two halves of a centre-tapped winding is within 5% and unlikely to cause a net d.c. flux in the transformer core that would substantially reduce the primary inductance value under PoE conditions. If surge protection is applied to the primary winding, the value of $R_P$ is a factor in surge coordination. The value of secondary winding resistance component, $R_S$ , needs to be taken into account for differential-mode surge conditions. [ITU-T K.95] uses the circuit shown in Figure 7-7 to measure winding resistance. + +![Figure 7-7: Resistance measurement diagrams. Diagram (a) shows a Digital Multimeter (DMM) connected across the secondary winding of an Ethernet port magnetics assembly (labeled T1). Diagram (b) shows a DMM connected across the primary winding of the same assembly. Both diagrams include labels for 'Signal input' and 'Signal output' terminals. The diagrams are labeled K.126(17)_F7-7.](33a8f3f01dfa8bce75d23017855a13c5_img.jpg) + +Figure 7-7: Resistance measurement diagrams. Diagram (a) shows a Digital Multimeter (DMM) connected across the secondary winding of an Ethernet port magnetics assembly (labeled T1). Diagram (b) shows a DMM connected across the primary winding of the same assembly. Both diagrams include labels for 'Signal input' and 'Signal output' terminals. The diagrams are labeled K.126(17)\_F7-7. + +$T_1$ Transformer or Ethernet port magnetics assembly incorporating transformer    DMM Digital multimeter or equivalent for measuring resistance + +**Figure 7-7 – Resistance measurement of a) secondary winding and b) primary winding** + +## 7.6 Saturated core secondary winding inductance + +The value of the secondary winding saturated-core inductance component, $L_{S(\text{SAT})}$ , together with the peak secondary current at transformer core saturation determine the secondary winding surge energy after core saturation. The value of $L_{S(\text{SAT})}$ is derived from a current decay time measurement and the secondary winding resistance component, $R_S$ . [ITU-T K.95] uses the circuit shown in Figure 7-8 to measure the shorted secondary winding current decay time, $\tau_{L/R}$ , for a 37% reduction in amplitude. The value of $L_{S(\text{SAT})}$ is the calculated as $\tau_{L/R} \cdot R_S$ . + +![Figure 7-8: Test circuit for measuring secondary short-circuit current under surge conditions. A surge generator G (1.2/50-8/20) is connected via a 12 ohm resistor RGEXT to the primary signal input of transformer T1. The secondary signal output is short-circuited through a current transformer CT, which is monitored by an oscilloscope O. The primary current is IGEN and the secondary short-circuit current is Is. Diagram reference K.126(17)_F7-8.](76b0cd79baaedd942af4dc42f2e764b8_img.jpg) + +Figure 7-8: Test circuit for measuring secondary short-circuit current under surge conditions. A surge generator G (1.2/50-8/20) is connected via a 12 ohm resistor RGEXT to the primary signal input of transformer T1. The secondary signal output is short-circuited through a current transformer CT, which is monitored by an oscilloscope O. The primary current is IGEN and the secondary short-circuit current is Is. Diagram reference K.126(17)\_F7-8. + +| | | | | +|-----------|---------------------------------------------------------------------------|------------|---------------------------------------------------------------| +| $T_1$ | Transformer or Ethernet port magnetics assembly incorporating transformer | G | 1.2/50-8/20 combinaison wave surge generator | +| CT | Current transformer or current probe | O | Oscilloscope or equivalent recording secondary current, $I_s$ | +| $I_s$ | Secondary winding short-circuit current | $R_{GEXT}$ | Generator external series resistor | +| $I_{GEN}$ | Primary winding current from the generator | | | + +**Figure 7-8 – Test circuit for measuring secondary short-circuit current +under surge conditions** + +# 8 Ratings + +## 8.1 Verification + +[ITU-T K.95] defines the test circuits and rating verification procedures for the transformer parameters discussed in this clause. + +## 8.2 Rated impulse voltage + +The common-mode rated impulse voltage value should be greater than or at least equal to the expected electrical environment. [ITU-T K.95] uses the circuit shown in Figure 8-1 to verify the transformer common-mode rated impulse voltage. After the rated impulse voltage test, the transformer has a further IR test (7.3) to check for any insulation degradation. + +![Figure 8-1: Transformer rated impulse voltage test circuit. The diagram shows a transformer with primary winding Wp and secondary winding Ws. Both windings are connected in common-mode to a surge generator G (1.2/50) and an oscilloscope O to monitor the impulse voltage. Diagram reference K.126(17)_F8-1.](51db757d054ce1ce83c436a3578b56ca_img.jpg) + +Figure 8-1: Transformer rated impulse voltage test circuit. The diagram shows a transformer with primary winding Wp and secondary winding Ws. Both windings are connected in common-mode to a surge generator G (1.2/50) and an oscilloscope O to monitor the impulse voltage. Diagram reference K.126(17)\_F8-1. + +| | | | | +|-------|-------------------|---|-------------------------------------------------------| +| $W_p$ | Primary winding | G | 1.2/50 surge generator | +| $W_s$ | Secondary winding | O | Oscilloscope or equivalent monitoring impulse voltage | + +**Figure 8-1 – Transformer rated impulse voltage test circuit** + +If the transformer has an electric screen between the primary and secondary windings, two rated impulse voltage test are performed; primary winding to screen and secondary winding to screen. [ITU-T K.95] uses the circuit shown in Figure 8-2 for these rated impulse voltage verifications. + +After the rated impulse voltage tests, the transformer has further IR tests (5.3) to check for any insulation degradation. + +![Figure 8-2: Rated impulse voltage test circuit for a transformer with an electric screen. The diagram shows a transformer with primary winding Wp, secondary winding Ws, and an electric screen ES. A two-position selector switch (SW) can connect the primary winding to either a 1.2/50 surge generator (G) or an oscilloscope (O) for monitoring the impulse voltage. The secondary winding is connected to ground. The circuit is labeled K.126(17)_F8-2 and 1.2/50.](7f25db95ce3916c0e09803b861a2f7bc_img.jpg) + +$W_p$ Primary winding      $G$ 1.2/50 surge generator + $W_s$ Secondary winding    $O$ Oscilloscope or equivalent monitoring impulse voltage + $ES$ Electric screen      $SW$ Two position selector switch + +Figure 8-2: Rated impulse voltage test circuit for a transformer with an electric screen. The diagram shows a transformer with primary winding Wp, secondary winding Ws, and an electric screen ES. A two-position selector switch (SW) can connect the primary winding to either a 1.2/50 surge generator (G) or an oscilloscope (O) for monitoring the impulse voltage. The secondary winding is connected to ground. The circuit is labeled K.126(17)\_F8-2 and 1.2/50. + +**Figure 8-2 – Rated impulse voltage test circuit for a transformer with an electric screen** + +## 8.3 Rated winding d.c. + +This parameter is only relevant under extreme conditions, such as a standard that demands a differential mode power cross test. [ITU-T K.95] uses the circuit shown in Figure 8-3 to verify that the transformer temperature rise is not excessive when conducting the rated value of d.c. Circuit a) measures the pre-test values of winding resistance and circuit b) measures the winding voltage at the rated d.c. and the local ambient temperature of the transformer after thermal equilibrium is reached. + +![Figure 8-3: Winding conductor temperature rise test circuit. The diagram consists of two parts, (a) and (b). Part (a) shows a transformer with primary winding Wp and secondary winding Ws. An ohmmeter (Ω) is connected across the primary winding to measure resistance. A thermocouple (TC) is connected to a meter (°C) to measure the local ambient temperature. Part (b) shows the same transformer with a current source (I) and a voltmeter (V) connected across the primary winding to measure the winding voltage at the rated d.c. The thermocouple (TC) and meter (°C) are also connected to measure the local ambient temperature. The circuit is labeled K.126(17)_F8-3.](898fb89a50d9ec1dfb4e425c816976a7_img.jpg) + +$W_p$ Primary winding      $\Omega$ Ohm meter to measure winding resistance + $W_s$ Secondary winding    $I$ Current source set to the winding rated dc, $I_{DC}$ + $TC$ Thermocouple, placed 10 mm $\pm$ 2 mm from    $V$ Voltmeter to measure winding voltage, $V_w$ + the transformer for sensing the local ambient + temperature + $^\circ C$ Meter measuring the local ambient temperature + +Figure 8-3: Winding conductor temperature rise test circuit. The diagram consists of two parts, (a) and (b). Part (a) shows a transformer with primary winding Wp and secondary winding Ws. An ohmmeter (Ω) is connected across the primary winding to measure resistance. A thermocouple (TC) is connected to a meter (°C) to measure the local ambient temperature. Part (b) shows the same transformer with a current source (I) and a voltmeter (V) connected across the primary winding to measure the winding voltage at the rated d.c. The thermocouple (TC) and meter (°C) are also connected to measure the local ambient temperature. The circuit is labeled K.126(17)\_F8-3. + +**Figure 8-3 – Winding conductor temperature rise test circuit** + +# 9 Application examples + +## 9.1 Transformer example + +To explain the role of the various isolating transformer parameters, the equivalent circuit shown in Figure 9-1 is used. There are some compromises in the model, such as lumped values for distributed parameters and the nodes to which the equivalent winding capacitances connect. + +![Figure 9-1: Transformer circuit model. The diagram illustrates an electrical equivalent circuit for a transformer connected to a 1.2/50-8/20 generator. The primary side includes R_GEN, 0.5 R_p, 0.5 L_LP, and 0.5 C_P-S. The transformer core is represented by magnetising inductance L_p and current I_MAG. The secondary side includes 0.5 C_P-S, 0.5 L_LS, 0.5 R_s, and a limiter circuit with R_LIM, a switch SW, and a clamping diode V_CL. The turns ratio is denoted by n.](81a4cbf0b3c4cbc065efdf8f800dadde_img.jpg) + +$R_p$ Primary winding resistance + $L_{LP}$ Primary leakage inductance + $R_{GEN}$ Series resistance from generator + $V_p$ Primary voltage + $C_{P-S}$ Inter-winding capacitance + $I_{GEN}$ Generator current + $I_{MAG}$ Magnetising current + $L_p$ Primary magnetising inductance + +$R_s$ Secondary winding resistance + $L_{LS}$ Secondary leakage inductance + $R_{LIM}$ Series resistance to limiter + $SW$ Switching voltage limiter + $V_{CL}$ Clamping limiter voltage + $L_s$ Secondary inductance + $n$ Transformer turns ratio + +Figure 9-1: Transformer circuit model. The diagram illustrates an electrical equivalent circuit for a transformer connected to a 1.2/50-8/20 generator. The primary side includes R\_GEN, 0.5 R\_p, 0.5 L\_LP, and 0.5 C\_P-S. The transformer core is represented by magnetising inductance L\_p and current I\_MAG. The secondary side includes 0.5 C\_P-S, 0.5 L\_LS, 0.5 R\_s, and a limiter circuit with R\_LIM, a switch SW, and a clamping diode V\_CL. The turns ratio is denoted by n. + +Figure 9-1 – Transformer circuit model + +Typical values for transformer parameters are given in Table 1. + +Table 1 – Typical Figure 9-1 PoE transformer parameter values + +| Component symbol | Value | Component symbol | Value | +|------------------|-------------------------------------------------------------------------------------------|------------------|-------------------------------------------------------------------| +| $R_p$ | 0.9 $\Omega$ max. (100 Base-T)
1.4 $\Omega$ max. (1000 Base-T) | $R_s$ | 0.9 $\Omega$ max. (100 Base-T)
1.4 $\Omega$ max. (1000 Base-T) | +| $L_{LP}$ | 0.25 $\mu H$ max. | $L_{LS}$ | 0.25 $\mu H$ max. | +| $L_p$ | 350 $\mu H$ min. at 8 mA d.c. (100 Base-T)
80 $\mu H$ min. at 28 mA d.c. (1000 Base-T) | $L_s$ | Similar to $L_p$ | +| $C_{P-S}$ | 25 pF typ. | $n$ | 1:1 | + +## 9.2 Common-mode surge + +### 9.2.1 Capacitive surge current + +The $dv/dt$ wavefront of a common-mode voltage surge creates the highest capacitive current, $i$ , as the voltage is changing at its fastest rate ( $dv/dt = i/C$ ). For a typical surge waveform, [b-Maytum, 1994] estimated that the initial rate of rise was three times that of the average given by the peak open-circuit voltage value divided by the front time. + +Figure 9-2 shows two situations: normal differential signal conditions; and common-mode surge conditions. The capacitive loops are: the primary to secondary capacitance loops ( $0.5 C_{P-S}$ ); and the + +Smith termination network loop [b-Smith] ( $C_S$ and $C_{PoE}$ ). The extra $C_{PoE}$ capacitor is necessary in PoE designs to block the DC powering voltage of the signal pairs. The peak Smith termination charging current will be less than $C_S \times (dv/dt)_{MAX}$ , as the current step is modified to an exponential rise by the $R_S \times C_S$ time constant. Some designs do not use a Smith termination circuit for reasons given in [b-Ardley]. + +Under normal differential signal conditions, capacitive currents are negligible as there is no common mode signal to drive Smith termination current or any net primary to secondary inter-winding current. + +![Figure 9-2: Smith circuit capacitive currents. The diagram consists of two parts: (a) Differential-mode signal conditions and (b) Common-mode surge conditions. Part (a) shows a circuit with a centre-tapped primary winding (Lp), a 'Smith' termination network (Rs, CpoE, Cs), and a transformed secondary load (RL). Part (b) shows the same circuit but with inter-winding capacitance components (0.5 Cp-s) and secondary load resistance components (0.5 RL) added. A legend below the diagrams defines the components and currents.](c5655e700cc3e9aac7e9f4f07f30264d_img.jpg) + +**Differential-mode signal conditions** +a) + +**Common-mode surge conditions** +b) + +K.126(17)\_F9-2 + +| | | | | +|-----------|------------------------------------------|---------------|--------------------------------------------------| +| $R_S$ | Smith termination resistor | $I_S$ | Smith termination current | +| $C_{PoE}$ | Smith termination PoE blocking capacitor | $0.5 C_{p-s}$ | Distributed inter-winding capacitance components | +| $C_S$ | Smith termination decoupling capacitor | $0.5 R_L$ | Balanced secondary load resistance components | +| $I$ | Input current | $I_S$ | Smith termination current | +| $R_L$ | Secondary load resistance component | $0.5 I_{p-s}$ | $0.5 C_{p-s}$ component current | +| $L_p$ | Centre-tapped primary winding | | | + +Figure 9-2: Smith circuit capacitive currents. The diagram consists of two parts: (a) Differential-mode signal conditions and (b) Common-mode surge conditions. Part (a) shows a circuit with a centre-tapped primary winding (Lp), a 'Smith' termination network (Rs, CpoE, Cs), and a transformed secondary load (RL). Part (b) shows the same circuit but with inter-winding capacitance components (0.5 Cp-s) and secondary load resistance components (0.5 RL) added. A legend below the diagrams defines the components and currents. + +**Figure 9-2 – Smith circuit capacitive currents** + +Under common-mode surge conditions, there will be Smith termination and inter-winding capacitive currents. The typical recommended values for the Smith termination components are; $R_S = 75 \Omega$ , $C_{PoE} = 10 \text{ nF } 200 \text{ V}$ and $C_S = 1 \text{ nF } 2 \text{ kV}$ . As the impulse test voltage used in [b-IEEE 802.3] is 2.4 kV, the design approach must be that a 2 kV rated capacitor can withstand a temporary overvoltage to 2.4 kV. + +Under differential signal conditions, with one signal polarity applied to one end of the centre-tapped primary winding and the opposite signal polarity applied to the other winding end, the primary has high impedance. Under common-mode surge conditions, when both ends of the centre-tapped primary winding have the same polarity applied, there is core flux cancellation making the winding essentially air-cored [b-Pulse]. In this state, the primary winding has negligible impedance and effectively shorts the winding ends and the centre-tap together. This means the common-mode surge voltage from both wires of the signal twisted pair are directly applied to the Smith termination circuit. + +Figures 9-3 and 9-4 show the Smith termination overall voltage, $V_S$ , capacitor $C_S$ voltage, $V_{CS}$ , and current, $I_S$ , for a surge delivered by a 1.2/50–8/20 generator charged to 2.5 kV for two twisted pairs and for all four twisted pairs. In the two pair case, with charging via two resistors, the current in one resistor peaks at about 1.9 A. In the four pair case, with charging via four resistors, the current in + +one resistor peaks at about 1.0 A. Surge measurements made in [b-Chaudhry] show that at surge levels approaching the enhanced level (6 kV), the higher charging currents and the consequent resistive energy tend to cause failure of the termination resistors. The selected resistor energy ratings and capacitor voltage ratings need to be adequate for the chosen electrical surge environment. + +![Figure 9-3: Smith termination voltages and current with two pairs connected. The graph plots Voltage (kV) on the left y-axis (0.0 to 2.4) and Current (A) on the right y-axis (0.0 to 2.0) against Time (μs) on the x-axis (0.0 to 2.4). Three curves are shown: a blue curve labeled I_s peaking at ~1.8 A at 0.1 μs and decaying; a red curve labeled V_s rising from 0 to ~2.2 kV; and a green curve labeled V_cs rising from 0 to ~2.0 kV. K.126(17)_F9-3 is noted at the bottom right.](ed75e80b1e08237f7e90b65357de84d5_img.jpg) + +Figure 9-3: Smith termination voltages and current with two pairs connected. The graph plots Voltage (kV) on the left y-axis (0.0 to 2.4) and Current (A) on the right y-axis (0.0 to 2.0) against Time (μs) on the x-axis (0.0 to 2.4). Three curves are shown: a blue curve labeled I\_s peaking at ~1.8 A at 0.1 μs and decaying; a red curve labeled V\_s rising from 0 to ~2.2 kV; and a green curve labeled V\_cs rising from 0 to ~2.0 kV. K.126(17)\_F9-3 is noted at the bottom right. + +**Figure 9-3 – Smith termination voltages and current with two pairs connected** + +![Figure 9-4: Smith termination voltages and current with four pairs connected. The graph plots Voltage (kV) on the left y-axis (0.0 to 2.4) and Current (A) on the right y-axis (0.0 to 1.1) against Time (μs) on the x-axis (0.0 to 2.4). Three curves are shown: a blue curve labeled I_s peaking at ~1.0 A at 0.1 μs and decaying; a red curve labeled V_s rising from 0 to ~2.2 kV; and a green curve labeled V_cs rising from 0 to ~2.0 kV. K.126(17)_F9-4 is noted at the bottom right.](7f687094e6abe34a9cf491942b296d9a_img.jpg) + +Figure 9-4: Smith termination voltages and current with four pairs connected. The graph plots Voltage (kV) on the left y-axis (0.0 to 2.4) and Current (A) on the right y-axis (0.0 to 1.1) against Time (μs) on the x-axis (0.0 to 2.4). Three curves are shown: a blue curve labeled I\_s peaking at ~1.0 A at 0.1 μs and decaying; a red curve labeled V\_s rising from 0 to ~2.2 kV; and a green curve labeled V\_cs rising from 0 to ~2.0 kV. K.126(17)\_F9-4 is noted at the bottom right. + +**Figure 9-4 – Smith termination voltages and current with four pairs connected** + +Under common-mode surge conditions, the inter-winding primary–secondary capacitance is charged and discharged. The example equivalent inter-winding capacitance is 10 pF between the primary and the secondary winding starts, together with a second 10 pF between the primary and the secondary winding finishes, see Figure 9-2. Figure 9-5 shows the 10 pF capacitor surge voltage, $V_{\text{SURGE}}$ , and current, $0.5I_{\text{P-S}}$ , for a surge delivered by a 1.2/50–8/20 generator charged to 2.5 kV. The resultant peak capacitive current is just under 50 mA. At the 6 kV enhanced test level, the capacitor current is about 120 mA. This level is not a significant secondary circuit stress, as the current levels caused by differential-mode surges are considerably higher. + +![Figure 9-5: Secondary capacitive current for a 10 pF inter-winding capacitance. The graph plots Voltage (kV) on the left y-axis (0.0 to 2.4) and Current (A) on the right y-axis (0 to 50) against Time (μs) on the x-axis (0.0 to 2.4). Two curves are shown: a blue curve labeled 0.5 I_P-S starting at 50 A and decaying; and a green curve labeled V_SURGE rising from 0 to ~2.2 kV. K.126(17)_F9-5 is noted at the bottom right.](f630450865788387c4821c6d5760c850_img.jpg) + +Figure 9-5: Secondary capacitive current for a 10 pF inter-winding capacitance. The graph plots Voltage (kV) on the left y-axis (0.0 to 2.4) and Current (A) on the right y-axis (0 to 50) against Time (μs) on the x-axis (0.0 to 2.4). Two curves are shown: a blue curve labeled 0.5 I\_P-S starting at 50 A and decaying; and a green curve labeled V\_SURGE rising from 0 to ~2.2 kV. K.126(17)\_F9-5 is noted at the bottom right. + +**Figure 9-5 – Secondary capacitive current for a 10 pF inter-winding capacitance** + +### 9.2.2 Switching voltage limiter discharge current + +If a switching voltage limiting function is present by the use of either an external SPD or SPCs in the equipment port, the switching action causes a rapid voltage change, much faster than that which + +occurs on the surge front. Assuming the SPD and the equipment port meet the IR requirements of 7.3, the rapid voltage decrease is likely to occur at voltages in excess of 700 V. + +Figure 9-6 shows the Smith termination current, $I_s$ , for a surge delivered by a 1.2/50–8/20 generator charged to 2.5 kV for two twisted pairs with an 800 V switching voltage limiter on one pair. The peak charging current is 1.9 A as in Figure 9-3, but the discharging current is higher, approaching –7 A. + +![Figure 9-6 – Smith termination discharge current caused by an 800 V switching voltage limiter](9b5411fa2d169b66f6185fbf67b49766_img.jpg) + +This graph plots Current (A) on the y-axis against Time (μs) on the x-axis. The y-axis ranges from -8 to 3 in increments of 1. The x-axis ranges from 0.0 to 1.0 in increments of 0.1. A single blue curve, labeled \$I\_s\$, starts at 0, rises to a peak of approximately 1.9 A at 0.2 μs, then drops sharply to a minimum of approximately -7 A at 0.25 μs, before recovering back towards 0 A, reaching near-zero by 0.6 μs and remaining stable until 1.0 μs. + +| Time (μs) | Current (A) | +|-----------|-------------| +| 0.0 | 0.0 | +| 0.1 | 1.5 | +| 0.2 | 1.9 | +| 0.25 | -7.0 | +| 0.3 | -4.0 | +| 0.4 | -1.0 | +| 0.6 | 0.0 | +| 1.0 | 0.0 | + +Figure 9-6 – Smith termination discharge current caused by an 800 V switching voltage limiter + +**Figure 9-6 – Smith termination discharge current caused by an 800 V switching voltage limiter** + +Figure 9-7 shows the 10 pF inter-winding capacitor surge voltage, $V_{SURGE}$ , and current, $I_{P-S}/2$ , for a surge delivered by a 1.2/50–8/20 generator charged to 2.5 kV with a connected 800 V switching voltage limiter. The resultant peak charging current is just under 50 mA as in Figure 9-5, but the discharging current is higher, reaching a peak of –4.5 A. In practice, the peak current and duration of the discharge current will depend on the switching waveform of the voltage limiter. + +![Figure 9-7 – Inter-winding capacitance discharge current caused by an 800 V switching voltage limiter](65f66758012e229247953202e8adf35d_img.jpg) + +This graph has dual y-axes. The left y-axis represents Voltage (V) from 0 to 1000. The right y-axis represents Current (A) from -4.5 to 0.5. The x-axis is Time (μs) from 0.0 to 1.0. A green curve (\$V\_{SURGE}\$) rises linearly from 0 V at 0 μs to 800 V at 0.2 μs, then drops instantly to 0 V. A blue curve (\$0.5 I\_{P-S}\$) stays at 0 A until 0.2 μs, then drops sharply to -4.5 A at approximately 0.22 μs, and returns to 0 A by 0.3 μs. + +| Time (μs) | Voltage (V) | Current (A) | +|-----------|-------------|-------------| +| 0.0 | 0 | 0.0 | +| 0.1 | 400 | 0.0 | +| 0.2 | 800 | 0.0 | +| 0.22 | 0 | -4.5 | +| 0.3 | 0 | 0.0 | +| 1.0 | 0 | 0.0 | + +Figure 9-7 – Inter-winding capacitance discharge current caused by an 800 V switching voltage limiter + +**Figure 9-7 – Inter-winding capacitance discharge current caused by an 800 V switching voltage limiter** + +The operation of a switching voltage limiter effectively shorts the cable conductors to the local functional bonding point and this can nearly double the peak voltage level on the equipment at the other end of the cable [b-Maytum, 2011]. A double voltage result is the same as that caused by the termination mismatch mechanism of an isolating power transformer reflecting the surge waveform back down the line (see Chapter 9 of [b-Hileman]). In addition, asynchronous voltage switching can convert common-mode surges into differential mode surges. + +The most elegant approach with the fewest consequences for Ethernet port design is to avoid the need for common-mode switching voltage limiters by using an isolating transformer with a withstand voltage rating greater than or equal to that of the expected electrical environment. + +## 9.3 DC insulation resistance + +[b-IEEE 802.3] requires that the Ethernet port IR at 500 V d.c. be 2 M $\Omega$ or greater. The test circuits are shown in 7.3. The 500 V d.c. test voltage has two implications. + +- Any common-mode voltage limiter must have an operating threshold above 500 V, otherwise the port will fail the IR test. +- The 500 V d.c. test level is higher than the peak voltage of 120 V and 230 V a.c. mains voltages, meaning that a single contact power cross can be withstood without current flow. + +The risk of getting a differential two contact power cross is highly unlikely, making such a test meaningless. Unfortunately many standards still apply old plain old telephone system (POTS) testing techniques to Ethernet ports, resulting in increased costs and probably no field benefits. + +## 9.4 Differential-mode primary winding surge + +### 9.4.1 Impulse generator configuration + +For Ethernet, ITU-T has standardized on the 1.2/50-8/20 generator. In the open circuit mode, it produces the 1.2/50 voltage impulse used for testing insulation [b-IEC 60060-1]. In terms of a common-mode current delivered to a low-impedance port, it has been found that a series resistor of 5 $\Omega$ gives a typical $I^2t$ value of 12 A2s, which is of the same order of magnitude as the value needed to cause observed field failures of fuses (rated at 15 A2s) and printed wiring tracks. + +The [b-ITU-T K.117] Ethernet common-mode generator configuration is shown in Figure 9-8 a). If a differential-mode surge is created by breakdown or voltage limiter operation at one cable end twisted pair and the same happens at the other end of the cable, the surge current is shared between the two conductors of the twisted pair. In this case, the differential surge current into the port will be half the common-mode surge current. Figure 9-8 b) shows how this is implemented using the common-mode generator voltage settings. Half the generator output current is taken by the shunt resistor $R_{GEN2}$ (10 $\Omega$ ) and the other half of the generator current is applied to the equipment port via series resistor $R_{GEN1}$ (10 $\Omega$ ). Together the two resistors form a generator load of 5 $\Omega$ , making the surge current waveshape the same for common-mode and differential-mode surges. + +![Figure 9-8 shows two circuit diagrams for impulse generator configurations. Diagram (a) shows a 1.2/50-8/20 generator connected in series with a 5 Ohm resistor (R_GEN1). Diagram (b) shows a 1.2/50-8/20 generator connected in parallel with a 10 Ohm resistor (R_GEN2) and a series combination of a 10 Ohm resistor (R_GEN1) and the equipment port. The label K.126(17)_F9-8 is present in diagram (b).](171115f072e42b379238ed0dd438e9d7_img.jpg) + +The diagram consists of two parts, (a) and (b), illustrating different impulse generator configurations. + Part (a) shows a box labeled '1.2/50-8/20 generator' connected in series with a resistor labeled $R_{GEN1}$ and $5 \Omega$ . + Part (b) shows a box labeled '1.2/50-8/20 generator' connected in parallel with a resistor labeled $R_{GEN2}$ and $10 \Omega$ . This parallel combination is then connected in series with a resistor labeled $R_{GEN1}$ and $10 \Omega$ . The label 'K.126(17)\_F9-8' is present in the bottom right of diagram (b). + Below the diagrams are two captions: + a) Common-mode impulse generator configuration + b) Differential-mode impulse generator configuration + +Figure 9-8 shows two circuit diagrams for impulse generator configurations. Diagram (a) shows a 1.2/50-8/20 generator connected in series with a 5 Ohm resistor (R\_GEN1). Diagram (b) shows a 1.2/50-8/20 generator connected in parallel with a 10 Ohm resistor (R\_GEN2) and a series combination of a 10 Ohm resistor (R\_GEN1) and the equipment port. The label K.126(17)\_F9-8 is present in diagram (b). + +Figure 9-8 – Common-mode and differential-mode impulse generator configurations + +### 9.4.2 Saturating core transformer surge conditions + +Under differential surge conditions, see Figure 9-10, a saturating core signal transformer has a secondary winding surge let-through current, $I_s$ , that is typically triangular and can be described by three surge waveform parameters of front, peak and decay as follows: + +- Waveform **front** due to transformer linear surge current transfer from primary winding to secondary winding, the current ratio being set by the transformer's primary to secondary turn's ratio, $n$ . +- Waveform **peak** determined by the transformer core saturation event setting the peak secondary current, the event time being set by the transformer's volt-second (V·s) value for core saturation. +- Waveform **decay** due to the saturated core secondary winding stored energy dump, the current waveform of which is set by the transformer saturated core winding inductance, the + +secondary leakage inductance, the peak secondary current, the secondary winding resistance and the secondary load impedance. + +Figure 9-9 shows an example waveform with the three waveform parameters indicated. + +![Figure 9-9: Example waveform of transformer secondary winding differential surge let-through current. The graph plots current in Amperes (0 to 40 A) on the vertical axis against time in microseconds (0 to 5 μs) on the horizontal axis. The waveform rises linearly from 0 to a peak of approximately 35 A at 0.5 μs, labeled 'Front (linear)' and 'Peak (core saturation)'. After the peak, it decays exponentially, labeled 'Decay (secondary winding energy dump)'.](5500ab73cf84ccc0055eecf28889b4db_img.jpg) + +Figure 9-9: Example waveform of transformer secondary winding differential surge let-through current. The graph plots current in Amperes (0 to 40 A) on the vertical axis against time in microseconds (0 to 5 μs) on the horizontal axis. The waveform rises linearly from 0 to a peak of approximately 35 A at 0.5 μs, labeled 'Front (linear)' and 'Peak (core saturation)'. After the peak, it decays exponentially, labeled 'Decay (secondary winding energy dump)'. + +**Figure 9-9 – Example waveform of transformer secondary winding differential surge let-through current** + +![Figure 9-10: Effective secondary circuit for differential surge. The diagram shows a 1.2/50-8/20 generator connected to a transformer model. The primary side includes series resistors R_GEN1, R_p, and leakage inductance L_LP. The magnetizing branch has inductance L_p and current I_MAG. The secondary side includes leakage inductance L_LS, resistance R_s, and a limiter section with series resistance R_LIM, a switching voltage limiter (SW), and a clamping limiter (V_CL).](e354b57563dae469c00b412b2abdf765_img.jpg) + +Figure 9-10: Effective secondary circuit for differential surge. The diagram shows a 1.2/50-8/20 generator connected to a transformer model. The primary side includes series resistors R\_GEN1, R\_p, and leakage inductance L\_LP. The magnetizing branch has inductance L\_p and current I\_MAG. The secondary side includes leakage inductance L\_LS, resistance R\_s, and a limiter section with series resistance R\_LIM, a switching voltage limiter (SW), and a clamping limiter (V\_CL). + +| | | | | +|-----------|----------------------------------|--------------|-------------------------------------| +| $R_p$ | Primary winding resistance | $R_s$ | Secondary winding resistance | +| $L_{LP}$ | Primary leakage inductance | $L_{LS}$ | Secondary leakage inductance | +| $R_{GEN}$ | Series resistance from generator | $R_{LIM}$ | Series resistance to limiter | +| $V_p$ | Primary voltage | SW | Switching voltage limiter | +| $C_{P-S}$ | Inter-winding capacitance | $V_{CL}$ | Clamping limiter voltage | +| $I_{GEN}$ | Generator current | $L_s$ | Secondary inductance | +| $I_{MAG}$ | Magnetising current | $n$ | Transformer turns ratio | +| $L_p$ | Primary magnetising inductance | $L_{S(SAT)}$ | Saturated core secondary inductance | + +**Figure 9-10 – Effective secondary circuit for differential surge** + +### 9.4.3 Secondary current front + +During this period, the transformer operates in a linear mode, transforming the generator current in the primary to secondary winding current. The intrinsic secondary circuit voltage is the sum of the inductive voltage due to the rising current in the leakage inductance, any voltage limiter threshold voltage and the resistive voltages across the secondary resistance, the external secondary resistance and the effective limiter characteristic resistance. + +### 9.4.4 Secondary current peak + +The transformer action effectively ends when the transformer core saturates as shown by the primary magnetizing current, $I_{MAG}$ , dramatically increasing when the transformer volt-second value has been reached, see Figure 9-11. + +![Figure 9-11: Transformer primary magnetizing inductance voltage and current. The graph shows Voltage V (left axis, 0-70) and Current A (right axis, 0-100) versus Time μs (0-1.5). The voltage (blue line) rises linearly from 0 V at 0 μs to a peak of approximately 68 V at 0.5 μs, then drops sharply to 0 V. The current (green line) rises linearly from 0 A at 0 μs to a peak of approximately 95 A at 0.5 μs, then continues to rise linearly to approximately 100 A at 1.5 μs. The area under the voltage curve from 0 to 0.5 μs is shaded blue and labeled 'Magnetising inductance V-s area'. The voltage curve is labeled 'Magnetising inductance voltage' and the current curve is labeled 'Magnetising inductance current'. The graph is identified by the code K.126(17)_F9-11.](97f61e67792478fb6ce089868e503063_img.jpg) + +Figure 9-11: Transformer primary magnetizing inductance voltage and current. The graph shows Voltage V (left axis, 0-70) and Current A (right axis, 0-100) versus Time μs (0-1.5). The voltage (blue line) rises linearly from 0 V at 0 μs to a peak of approximately 68 V at 0.5 μs, then drops sharply to 0 V. The current (green line) rises linearly from 0 A at 0 μs to a peak of approximately 95 A at 0.5 μs, then continues to rise linearly to approximately 100 A at 1.5 μs. The area under the voltage curve from 0 to 0.5 μs is shaded blue and labeled 'Magnetising inductance V-s area'. The voltage curve is labeled 'Magnetising inductance voltage' and the current curve is labeled 'Magnetising inductance current'. The graph is identified by the code K.126(17)\_F9-11. + +**Figure 9-11 – Transformer primary magnetizing inductance voltage and current** + +The peak secondary current, $I_{S(PEAK)}$ at saturation will be roughly the surge generator $dI/dt$ multiplied by the time to reach core saturation, about 0.5 μs in this example. + +### 9.4.5 Secondary current decay + +During the waveform decay period, when the saturated core decouples the primary and secondary windings and the effective secondary circuit becomes the transformer saturated core winding inductance, $L_{S(SAT)}$ , the established secondary current, $I_{S(PEAK)}$ , the secondary winding resistance, $R_S$ , the limiter series resistance, $R_{LIM}$ , and the switching or clamping limiter threshold voltage and characteristic resistance are as shown in Figure 9-12. The stored energy of $0.5[L_{S(SAT)} + L_{LS}]I_{S(PEAK)}^2$ is discharged into the described circuit loop. + +![Figure 9-12: Secondary current decay circuit after core saturation. The circuit diagram shows a loop containing the following components in series: a saturated core secondary inductance component L_S(SAT), a secondary leakage inductance component L_LS, a secondary winding resistance component R_S, and a series resistance to limiter component R_LIM. A switching voltage limiter (SW) is connected in parallel with the series combination of L_LS, R_S, and R_LIM. The SW component is labeled 'Limiter switching/clamping' and has a clamping voltage V_CL. The current I_S flows through the circuit. The diagram is identified by the code K.126(17)_F9-12.](e821c3d8a87ee2a9ff6b8644ffe6bdae_img.jpg) + +Figure 9-12: Secondary current decay circuit after core saturation. The circuit diagram shows a loop containing the following components in series: a saturated core secondary inductance component L\_S(SAT), a secondary leakage inductance component L\_LS, a secondary winding resistance component R\_S, and a series resistance to limiter component R\_LIM. A switching voltage limiter (SW) is connected in parallel with the series combination of L\_LS, R\_S, and R\_LIM. The SW component is labeled 'Limiter switching/clamping' and has a clamping voltage V\_CL. The current I\_S flows through the circuit. The diagram is identified by the code K.126(17)\_F9-12. + +| | | | | +|-----------|----------------------------------------|--------------|-----------------------------------------------| +| $R_S$ | Secondary winding resistance component | $L_{S(SAT)}$ | Saturated core secondary inductance component | +| $R_{LIM}$ | Series resistance to limiter component | $L_{LS}$ | Secondary leakage inductance component | +| SW | Switching voltage limiter | $V_{CL}$ | Clamping limiter voltage | +| $I_S$ | Secondary current | | | + +**Figure 9-12 – Secondary current decay circuit after core saturation** + +There are two factors controlling the current decay rate: the ratio of the inductive components to the resistive components ( $L/R$ ); and the threshold voltage of the voltage limiter ( $V_{CL}/L$ ). + +### 9.4.6 Basic and enhanced test levels + +Figure 9-13 shows an example of the different secondary currents at the ITU-T basic (2.5 kV) and enhanced (6 kV) levels. + +![Figure 9-13: A line graph showing Current A (Y-axis, 0 to 50 A) versus Time μs (X-axis, 0.0 to 5.0 μs). Two curves are plotted: 'Enhanced (6kV) level' (blue line) and 'Basic (2.5 kV) level' (green line). The blue curve peaks at approximately 47.5 A at 0.4 μs, while the green curve peaks at 30 A at 0.5 μs. Both curves decay towards zero over time.](391ab9e5616ba6311161af4d7a93422b_img.jpg) + +| Time (μs) | Basic (2.5 kV) level (A) | Enhanced (6kV) level (A) | +|-----------|--------------------------|--------------------------| +| 0.0 | 0 | 0 | +| 0.5 | 30 | 40 | +| 1.0 | 15 | 25 | +| 1.5 | 8 | 15 | +| 2.0 | 4 | 8 | +| 2.5 | 2 | 4 | +| 3.0 | 1 | 2 | +| 4.0 | 0 | 0 | +| 5.0 | 0 | 0 | + +Figure 9-13: A line graph showing Current A (Y-axis, 0 to 50 A) versus Time μs (X-axis, 0.0 to 5.0 μs). Two curves are plotted: 'Enhanced (6kV) level' (blue line) and 'Basic (2.5 kV) level' (green line). The blue curve peaks at approximately 47.5 A at 0.4 μs, while the green curve peaks at 30 A at 0.5 μs. Both curves decay towards zero over time. + +Figure 9-13 – Basic and enhanced secondary current levels + +It is perhaps not intuitive that increasing the test voltage by $6/2.5 = 2.4$ times only increases the peak secondary current by $47.5/30 = 1.6$ times. The reason for this is that the transformer volt second parameter is fixed and this means that the peak current to generator voltage relationship is like a square root law $(6/2.5)^{0.5} = 1.55$ . The bulk of the energy deposited in the voltage limiter comes from the decay period and the secondary protection components should be selected accordingly. + +### 9.4.7 Alternative impulse generators + +[b-GR-1089] and [b-ATIS-0600036], originating from the USA, offer a $<2/>10^1$ as an alternative to the 1.2/50–8/20 generator. The open-circuit generator voltages are set at 800 V, which is lower than the ITU-T 2.5 kV (basic) and 6 kV (enhanced) levels, and these lower voltage levels will increase the generator and equipment interaction. To make both generators produce the same short circuit current of 100 A at the 800 V setting, a 6 Ω series resistor is placed in the 1.2/50–8/20 generator output. + +The circuit generator, $I_{GEN}$ , and secondary, $I_S$ , currents of the $<2/>10$ and 1.2/50–8/20 configurations are shown in Figure 9-14. + +1 The waveshape designator normally quotes the nominal wavefront time and nominal time to half value. Where the waveshape quotes the maximum front time and the minimum time to half value the $<$ and $>$ symbols are used before the times. For more information on this type of waveshape see [b-ITU-T K.96]. + +![Two line graphs showing generator and secondary currents over time for two different generator types. The top graph is for a 1.2/50-8/20 generator, and the bottom graph is for a <2/>10 generator. Both graphs plot Current A (0 to 100) against Time μs (0.0 to 5.0). The green trace represents the generator current (I_GEN) and the blue trace represents the secondary current (I_s).](2a23751710f7827065d2b99b6df588df_img.jpg) + +The figure consists of two vertically stacked line graphs. Both graphs have a y-axis labeled 'Current A' ranging from 0 to 100 in increments of 10, and an x-axis labeled 'Time μs' ranging from 0.0 to 5.0 in increments of 0.5. A grid is present in both plots. + +**Top Graph: 1.2/50-8/20 generator** + +- The green trace ( $I_{GEN}$ ) starts at 0 A at 0 μs, rises to a peak of approximately 25 A at 0.5 μs, and then continues to rise more slowly, reaching about 95 A at 5.0 μs. +- The blue trace ( $I_s$ ) starts at 0 A at 0 μs, rises to a peak of approximately 25 A at 0.5 μs, and then decays towards 0 A by 5.0 μs. + +**Bottom Graph: <2/>10 generator** + +- The green trace ( $I_{GEN}$ ) starts at 0 A at 0 μs, rises very sharply to a peak of approximately 45 A at 0.5 μs, and then continues to rise to about 95 A at 5.0 μs. +- The blue trace ( $I_s$ ) starts at 0 A at 0 μs, rises to a peak of approximately 30 A at 0.5 μs, and then decays towards 0 A by 5.0 μs. + +A small label 'K.126(17)\_F9-14' is located in the bottom right corner of the bottom graph. + +Two line graphs showing generator and secondary currents over time for two different generator types. The top graph is for a 1.2/50-8/20 generator, and the bottom graph is for a <2/>10 generator. Both graphs plot Current A (0 to 100) against Time μs (0.0 to 5.0). The green trace represents the generator current (I\_GEN) and the blue trace represents the secondary current (I\_s). + +**Figure 9-14 – Generator (green trace) and secondary (blue trace) currents for 1.2/50–8/20 and <2/>10 generators** + +There are three obvious differences in the waveforms: + +- The 1.2/50–8/20 generator current has a slower rate of rise. +- The 1.2/50–8/20 generator current has a smaller current step at core saturation due to its higher output impedance. +- The <2/>10 secondary peak current is higher due to its faster rate of rise. + +The <2/>10 generator secondary circuit stress is the highest. The two generator stresses can be equalized by raising the 1.2/50–8/20 generator open-circuit voltage to about 1 200 V because the resultant initial $dI/dt$ of the front then equals that of the <2/>10 generator. Figure 9-15 shows in detail the difference in the secondary currents and, for comparison, the ITU-T basic level secondary current. It shows that the secondary currents of the <2/>10 and ITU-T basic are very similar and the 1.2/50–8/20 peak secondary current is some 6 A lower. In selecting a generator for the differential testing of a transformer primary winding, the key parameter is the front initial $dI/dt$ . + +![Figure 9-15: Comparison of secondary currents from three different configurations. The graph plots Current (A) on the y-axis from 0 to 30 against Time (μs) on the x-axis from 0.0 to 5.0. Three curves are shown: 'ITU-T basic' (black), '<2>/10' (green), and '1.2/50-8/20' (blue). All curves rise sharply to a peak at approximately 0.5 μs. The 'ITU-T basic' and '<2>/10' curves peak at ~29.5 A, while the '1.2/50-8/20' curve peaks at ~23 A. All curves decay towards zero, reaching near-zero values by 3.0 μs. A legend box is located in the upper right quadrant. A small identifier 'K.126(17)_F9-15' is in the bottom right corner.](4cec89a753c447a050c0171c274f2acb_img.jpg) + +| Time (μs) | ITU-T basic (A) | <2>/10 (A) | 1.2/50-8/20 (A) | +|-----------|-----------------|------------|-----------------| +| 0.0 | 0 | 0 | 0 | +| 0.5 | 29.5 | 29.5 | 23 | +| 1.0 | 16 | 16 | 15 | +| 2.0 | 5 | 5 | 4 | +| 3.0 | 0.5 | 0.5 | 0.2 | + +Figure 9-15: Comparison of secondary currents from three different configurations. The graph plots Current (A) on the y-axis from 0 to 30 against Time (μs) on the x-axis from 0.0 to 5.0. Three curves are shown: 'ITU-T basic' (black), '<2>/10' (green), and '1.2/50-8/20' (blue). All curves rise sharply to a peak at approximately 0.5 μs. The 'ITU-T basic' and '<2>/10' curves peak at ~29.5 A, while the '1.2/50-8/20' curve peaks at ~23 A. All curves decay towards zero, reaching near-zero values by 3.0 μs. A legend box is located in the upper right quadrant. A small identifier 'K.126(17)\_F9-15' is in the bottom right corner. + +**Figure 9-15 – Comparison of secondary currents from three different configurations** + +## 9.5 Rated impulse voltage + +The common-mode rated impulse voltage value should be greater than or at least equal to the expected electrical environment. Often it is not realized that to guarantee the rated impulse voltage value the component must be capable of withstanding a substantially higher voltage value. + +Table 2 lists the preferred values for the transformer insulation rated impulse voltage together with the corresponding impulse withstand test voltage. To verify that the insulation rated impulse voltage is at least its specified value, the applied impulse withstand test voltage must be higher. The ratio of impulse withstand to rated impulse voltage used in Table 2 is 1.17 for voltages less than 4 kV and 1.23 for voltages of 4 kV and above in accordance with [b-IEC 60664-1] and [b-IEC/TR 60664-2-1]. + +**Table 2 – Impulse withstand test voltage for rated impulse voltage** + +| Rated impulse voltage (kV) | Impulse withstand voltage a (kV) | +|----------------------------|---------------------------------------------| +| 2.4
(see Note) | 2.8 | +| 2.5 | 2.92 | +| 6 | 7.39 | +| 12 | 14.8 | +| 15 | 18.5 | +| 25 | 30.8 | + +NOTE – The transformer impulse withstand voltage corresponding to the 1.2/50, 2.4 kV rated impulse voltage used for the equipment port test of [b-IEEE 802.3] is 2.8 kV. + +a The 1.2/50 peak voltage amplitude tolerance shall be $\pm 5\%$ in accordance with [b-IEC/TR 60664-2-1]. + +To satisfy [b-IEEE 802.3], the rated impulse voltage should be at least 2.4 kV or preferably 2.5 kV. This requirement will meet basic Ethernet port needs. In more severe electrical environments, such as home networking, an enhanced 6 kV rated impulse value is recommended. In special cases, values of 12 kV and above may be necessary. + +## 9.6 Rated winding d.c. + +Generally, the primary resistance value, represented by $R_P$ , and, for centre-tapped primaries, the resistive matching of the two primary halves, is of more interest than the winding current capability. The primary resistance represents a power loss for PoE applications, as the d.c. powering current flows through the transformer primary or in some cases a centre-tapped choke. The resistive match is important to avoid a net d.c. flux in the core, which can change the winding inductance. + +As pointed out in clause 8.3, rated current is only needed in extreme circumstances. The only other reason to specify this parameter is to match standardized wire current ratings. For example, at the time of writing, specifying a maximum wire current of 0.75 A d.c. per conductor at 60 °C is under consideration,2 which would result in a centre-tap rated current of 1.5 A d.c. + +--- + +2 In Draft International Standard IEC 60364-7-716, *Low-Voltage electrical installations – Part 7-716: Requirements for special installations or locations – DC power distribution over Information Technology Cable Infrastructure*. + +## Annex A + +## Use of isolating transformers for a.c. power and signal applications + +(This annex forms an integral part of this Recommendation.) + +For mitigation measures of lightning surge, there are some methods such as appropriate earthing and bonding, addition of SPD and isolation. Lightning isolation transformers (LITs) are components for isolation mitigation measure. This Annex shows the mitigation measures by isolation of surges and the application methods for LITs to improve resistibility against overvoltage at the design step. + +## A.1 Application of LITs to equipment that requires isolation + +The surge mitigation measure for equipment that requires to be isolated is to prevent surges from entering with LITs and not SPDs. + +![Figure A.1-1: Surge mitigation measure with SPDs. The diagram shows a central 'Equipment' block connected to 'Line' on the left and 'AC mains' on the right. On the 'Line' side, a GDT (Gas Discharge Tube) is connected between the line and ground. On the 'AC mains' side, a Varistor is connected between the line and ground. The diagram is labeled K.126(17)_FA.1-1.](98e54d5540b2efe3e24af3cf936bc4ea_img.jpg) + +Figure A.1-1: Surge mitigation measure with SPDs. The diagram shows a central 'Equipment' block connected to 'Line' on the left and 'AC mains' on the right. On the 'Line' side, a GDT (Gas Discharge Tube) is connected between the line and ground. On the 'AC mains' side, a Varistor is connected between the line and ground. The diagram is labeled K.126(17)\_FA.1-1. + +Figure A.1-1 – Surge mitigation measure with SPDs + +![Figure A.1-2: Surge mitigation measure with LITs. The diagram shows a central 'Equipment' block connected to 'Line' on the left and 'AC mains' on the right. The 'Line' is connected to the equipment through an isolating transformer (LIT). The 'AC mains' is also connected to the equipment through an isolating transformer (LIT). The diagram is labeled K.126(17)_FA.1-2.](dc1f232cfd39be5c20b21374ad4c04c0_img.jpg) + +Figure A.1-2: Surge mitigation measure with LITs. The diagram shows a central 'Equipment' block connected to 'Line' on the left and 'AC mains' on the right. The 'Line' is connected to the equipment through an isolating transformer (LIT). The 'AC mains' is also connected to the equipment through an isolating transformer (LIT). The diagram is labeled K.126(17)\_FA.1-2. + +Figure A.1-2 – Surge mitigation measure with LITs + +## A.2 Application of LITs on communication line for high-speed signal transmission + +When SPDs as surge mitigation measure apply to high speed signal transmission such as Ethernet, it may cause the decrease of LCL and the increase of transmission loss. In such cases, the use of LIT is recommended to prevent surges from entering. + +![Figure A.2-1: Surge mitigation measure with SPDs. The diagram shows two 'Equipment' blocks connected by a 'Communication line'. A GDT (Gas Discharge Tube) is connected between the communication line and ground. The diagram is labeled K.126(17)_FA.2-1.](dfa6249d64e9f63db89f2c5b7bbd01de_img.jpg) + +Figure A.2-1: Surge mitigation measure with SPDs. The diagram shows two 'Equipment' blocks connected by a 'Communication line'. A GDT (Gas Discharge Tube) is connected between the communication line and ground. The diagram is labeled K.126(17)\_FA.2-1. + +Figure A.2-1 – Surge mitigation measure with SPDs + +![Diagram of surge mitigation measures with LITs on a communication line between two equipment blocks.](692541e65db4dc852988ce77ebb60ce5_img.jpg) + +This diagram shows two rectangular blocks labeled "Equipment" connected by a horizontal line labeled "Communication line". A dashed vertical line labeled "LIT" (Line Impedance Transformer) is positioned in the middle of the communication line. The LIT is represented by two overlapping sets of three concentric arcs, symbolizing a transformer or inductor. + +Diagram of surge mitigation measures with LITs on a communication line between two equipment blocks. + +K.126(17)\_FA.2-2 + +**Figure A.2-2 – Surge mitigation measures with LITs** + +## A.3 LITs for equipment with low resistibility + +The operating voltage and speed are important for SPDs used for the equipment with low resistibility. When the operating voltage cannot be set lower, the insertion of resistors on transmission lines makes SPD operate efficiently. However, they cause the increase of transmission loss. LITs realize surge mitigation without influence on signal transmission by considering signal characteristics. + +![Diagram of surge protection coordination with resistors and GDTs.](933ecd14c858bf3fc919222d8e357bc8_img.jpg) + +This diagram illustrates surge protection coordination. On the left, a "Line" enters a rectangular "Equipment" block through two resistors in series. A Gas Discharge Tube (GDT) is connected between these lines and the "Earthing" (ground) symbol. On the right, the "Equipment" is connected to "AC mains" through an "LIT" (represented by overlapping arcs). A "Varistor" is connected between the AC mains lines and the "Earthing" symbol. + +Diagram of surge protection coordination with resistors and GDTs. + +K.126(17)\_FA.3-1 + +**Figure A.3-1 – Example of surge protection coordination with resistors** + +![Diagram of surge mitigation measure with LITs.](f0b7abcb093621bb310bf61fbe0f0d2d_img.jpg) + +This diagram shows a surge mitigation measure using LITs. On the left, a "Line" enters a rectangular "Equipment" block through an "LIT" (represented by overlapping arcs). A GDT is connected between the lines before the LIT and the "Earthing" symbol. On the right, the "Equipment" is connected to "AC mains" through another "LIT". A "Varistor" is connected between the AC mains lines and the "Earthing" symbol. + +Diagram of surge mitigation measure with LITs. + +K.126(17)\_FA.3-2 + +**Figure A.3-2 – Surge mitigation measure with LITs** + +# Bibliography + +- [b-ITU-T K.96] Recommendation ITU-T K.96 (2014), *Surge protective components: Overview of surge mitigation functions and technologies.* +- [b-ITU-T K.117] Recommendation ITU-T K.117 (2016), *Primary protector parameters for the surge protection of equipment Ethernet ports.* +- [b-ATIS-0600036] ATIS-0600036 (2016). *Electrical protection for Ethernet Systems.* +- [b-GR-1089] GR-1089:2011. *Electromagnetic compatibility and electrical safety – Generic criteria for network telecommunications equipment.* +- [b-IEC 60050-151] IEC 60050-151:2001, Ed. 2.0: *International Electrotechnical Vocabulary – Part 151: Electrical and magnetic devices.* +- [b-IEC 60060-1] IEC 60060-1:2010, *High-voltage test techniques – Part 1: General definitions and test requirements.* +- [b-IEC 60065] IEC 60065:2014, *Audio, video and similar electronic apparatus – Safety requirements.* +- [b-IEC 60099-4] IEC 60099-4:2014, *Surge arresters – Part 4: Metal-oxide surge arresters without gaps for a.c. systems.* +- [b-IEC 60617] IEC 60617:2012 DB, *Graphical symbols for diagrams.* +- [b-IEC 60664-1] IEC 60664-1:2007, *Insulation coordination for equipment within low-voltage systems – Part 1: Principles, requirements, and tests.* +- [b-IEC/TR 60664-2-1] IEC/TR 60664-2-1:2011, *Insulation coordination for equipment within low-voltage systems – Part 2-1: Application guide – Explanation of the application of the IEC 60664 series, dimensioning examples and dielectric testing.* +- [b-IEC 62475] IEC 62475:2010, *High-current test techniques – Definitions and requirements for test currents and measuring systems.* +- [b-IEC 62631-1] IEC 62631-1:2011, *Dielectric and resistive properties of solid insulating materials – Part 1: General.* +- [b-IEEE 802.3] IEEE 802.3™-2015, *IEEE standard for Ethernet.* +- [b-Ardley] Ardley, T. (2016). *Protecting PoE PSE and Ethernet to the latest international OSP standards.* Paper presented at: Alliance for Telecommunications Industry Solutions Protection Engineers Group Conference. Washington, DC: ATIS. Available (viewed 2017-06-04) at: [http://www.atis.org/peg/2016/protecting\\_poe-tardley.pdf](http://www.atis.org/peg/2016/protecting_poe-tardley.pdf) +- [b-Chaudhry] Chaudhry, N. (2013). *Ground or not to ground Ethernet protection (Part 2).* Paper presented at: Alliance for Telecommunications Industry Solutions Protection Engineers Group Conference. Washington, DC: ATIS. Available (viewed 2017-06-04) at: +- [b-Hileman] Hileman, Andrew R., *Insulation coordination for power systems*, Chapter 9, CRC Press, 1999, ISBN-10: 0824799577. +- [b-Hileman] Hileman, A.R. (1999). *Insulation coordination for power systems*. CRC Press. 767 pp. ISBN 9780824799571. +- [b-Maytum, 1994] Maytum, M., Rutgers, K., Unterweger, D. (1994). Lightning surge voltage limiting and survival properties of telecommunication thyristor-based + +protectors. In: *Electrical Overstress–Electrostatic Discharge Symposium Proceeding*, pp. 182–192. EOS/ESD Association. + +- [b-Maytum, 2011] Maytum, M. (2011). IEEE Std. 802.3 *Ethernet ports – Types, surge capability and applications*, Paper presented at: Alliance for Telecommunications Industry Solutions Protection Engineers Group Conference. Washington, DC: ATIS. +- [b-Pulse] Pulse (1999). [Understanding common mode noise](http://www.pulseelectronics.com/wp-content/uploads/2016/12/G019.pdf), G019A. 7 pp. Available (viewed 2017-06-04) at: <> +- [b-Smith] Patent US 5321372 A (1994). Smith, R.W. *Apparatus and method for terminating cables to minimize emissions and susceptibility*. +- [b-Snelling, 1983] Snelling, E.C., Giles, A.D. (1983). *Ferrites for inductors and transformers*. Research Studies Press LTD. Letchworth, Hertfordshire, England. John Wiley & Sons Inc. +- [b-Snelling, 1988] Snelling, E.C. (1988). *Soft ferrites: Properties and applications, 2nd edition*. London: Butterworths. 366 pp. ISBN 0408027606. + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.128-201801-I_PDF-E/raw.md b/marked/K/T-REC-K.128-201801-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..2eb0d9a9c30ae39fcd4541593cda5eedf59bb142 --- /dev/null +++ b/marked/K/T-REC-K.128-201801-I_PDF-E/raw.md @@ -0,0 +1,1618 @@ + + +International Telecommunication Union + +# **ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +# **K.128** + +(01/2018) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Surge protective component application guide – +metal oxide varistor (MOV) components** + +Recommendation ITU-T K.128 + +**ITU-T** + +![ITU logo: A globe with a red lightning bolt striking it, with the text 'ITU International Telecommunication Union' to the right.](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a blue globe with a red lightning bolt striking it from the top right. To the right of the globe, the text "ITU" is written in a large, bold, blue font, and below it, "International Telecommunication Union" is written in a smaller, blue font. + +ITU logo: A globe with a red lightning bolt striking it, with the text 'ITU International Telecommunication Union' to the right. + + + +# Recommendation ITU-T K.128 + +# Surge protective component application guide – metal oxide varistor (MOV) components + +## Summary + +Recommendation ITU-T K.128 describes metal oxide varistor (MOV) construction, non-linearity modelling, impedance properties, equivalent circuit, element temperature distribution, time factors, degradation and failure modes, operation states and application examples. These surge protective components (SPCs) are intended for the protection of exchange and outdoor equipment, subscriber or customer equipment and telecommunication lines from surges. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|------------------------------------------------------------------------------| +| 1.0 | ITU-T K.128 | 2018-01-13 | 5 | 11.1002/1000/13451 | + +## Keywords + +Application examples, degradation, metal oxide varistor, modelling, non-linearity index, operating states, surge, voltage limiter. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2018 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|------|------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 3.1 | Terms defined elsewhere ..... | 1 | +| 3.2 | Terms defined in this Recommendation..... | 4 | +| 4 | Abbreviations and acronyms ..... | 4 | +| 5 | Conventions ..... | 5 | +| 6 | Construction..... | 5 | +| 6.1 | Introduction ..... | 5 | +| 6.2 | Packaging ..... | 5 | +| 6.3 | Ceramic element structure..... | 6 | +| 6.4 | Ceramic element as a network..... | 8 | +| 7 | Modelling MOV non-linearity..... | 8 | +| 7.1 | Nonlinearity index ..... | 8 | +| 7.2 | Resistance formula ..... | 10 | +| 7.3 | MOV V-I characteristic graphs ..... | 12 | +| 7.4 | Other non-linear resistance effects ..... | 15 | +| 8 | Impedance properties and equivalent circuit ..... | 17 | +| 8.1 | General ..... | 17 | +| 8.2 | Non-linear resistance RV ..... | 18 | +| 8.3 | Leakage resistance Rins ..... | 18 | +| 8.4 | Capacitance CV ..... | 18 | +| 8.5 | Linear resistance RG ..... | 18 | +| 8.6 | Inductance LV ..... | 18 | +| 9 | Ceramic element current and temperature distribution ..... | 19 | +| 9.1 | Introduction ..... | 19 | +| 9.2 | Thermal properties..... | 20 | +| 10 | Time factors ..... | 23 | +| 10.1 | Initial response to an impulse ..... | 23 | +| 10.2 | AC power frequency currents..... | 24 | +| 11 | Degradation and failure modes..... | 26 | +| 11.1 | Stresses that may cause degradation..... | 26 | +| 11.2 | Impulse current degradation ..... | 27 | +| 11.3 | Failure criteria ..... | 28 | +| 11.4 | Additional MOV behaviours and effects..... | 29 | +| 12 | Operation states and related performances ..... | 29 | +| 12.1 | Typical operation states and basic requirements ..... | 29 | + +| | Page | | +|-------------------|-----------------------------------------------------------------------------------------------|----| +| 12.2 | Operational performances related to standby operation state..... | 30 | +| 12.3 | Operational performances related to surge suppression state..... | 32 | +| 12.4 | Operational performance related to TOV endurance state ..... | 33 | +| 12.5 | Impulse life ..... | 33 | +| 13 | Application examples ..... | 35 | +| 13.1 | Introduction ..... | 35 | +| 13.2 | Operation principles of a basic overvoltage protective system ..... | 35 | +| 13.3 | Classification of applications of MOV's and standards requirements..... | 37 | +| 13.4 | Connection modes of MOV in application circuits ..... | 37 | +| 13.5 | Quantitative relationship between voltages of the MOV for power
circuitry protection ..... | 38 | +| 13.6 | Series connection and parallel connection examples ..... | 39 | +| Appendix I – | Peak displacement and negative dynamic resistance..... | 42 | +| Bibliography..... | | 43 | + +## Introduction + +Recommendation ITU-T K.128 provides application guidance for the components covered by Recommendation ITU-T K.77, *Characteristics of metal oxide varistors for the protection of telecommunication installations*. This application guide provides two levels of information; overview and in-depth technical analysis. + + + +# Recommendation ITU-T K.128 + +# Surge protective component application guide – metal oxide varistor (MOV) components + +# 1 Scope + +This Recommendation in the surge protective component application guide series covers metal oxide varistor (MOV) voltage limiting components. These surge protective components (SPCs) are clamping type overvoltage protectors [b-ITU-T K.96]. These SPCs are used for the protection of power supply circuits and signal circuits of telecommunication installations against overvoltages. Guidance is given on construction, characteristics, ratings and application examples. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T K.77] Recommendation ITU-T K.77 (2009), *Characteristics of metal oxide varistors for the protection of telecommunication installations*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined in [ITU-T K.77]: + +**3.1.1 applied voltage ratio ( $R_{ap}$ ):** Ratio of d.c. voltage or peak of a.c. voltage applied on the MOV to the varistor voltage $U_N$ . + +**3.1.2 clamping voltage ( $U_{cla}$ ):** Maximum peak voltage across the MOV measured under conditions of a specified waveform impulse with current peak $I_P$ . If there is both a front peak and rear peak on the voltage waveform, the rear peak voltage is defined as the clamping voltage. + +NOTE – For an individual MOV, peak voltages shall be measured in two directions, and the larger value of the two is referred to as the clamping voltage of this MOV. + +**3.1.3 clamping voltage ratio ( $R_{cla}$ ):** Ratio of the clamping voltage $U_{cla}$ to the varistor voltage $U_N$ ( $R_{cla} = U_{cla}/U_N$ ). + +**3.1.4 combination impulse (1.2/50-8/20):** Impulse with open-circuit voltage of 1.2/50 $\mu\text{s}$ ( $T_1/T_2$ ) and short-circuit current of 8/20 $\mu\text{s}$ ( $T_1/T_2$ ), which is expressed by "voltage peak/current peak". + +NOTE – Unless otherwise specified, the effective impedance shall be 2 $\Omega$ , which is the quotient of the open-circuit voltage peak $U_P$ and the short-circuit current peak $I_P$ . + +**3.1.5 current peak de-rating curve:** Curves expressing the relationship of the three variables of $I_P$ , $n$ , $\tau$ , where $I_P$ is impulse current peak, $\tau$ is the impulse width, and $n$ is average application numbers of the impulse that the MOV can withstand in terms of specified pass criterion. The current $I_P$ shall be de-rated with the increasing of $\tau$ and/or $n$ , that may be represented by equations 3-1 and 3-2. + +$$\lg I_g = A - a \lg n \quad (\tau = \text{constant}) \quad (3-1)$$ + +$$\lg I_g = B - b \lg \tau \quad (n = \text{constant}) \quad (3-2)$$ + +Where $A$ , $a$ , $B$ and $b$ are four constants which depend on the type and manufacturing of the MOV, also $A$ and $a$ depend on $\tau$ values, $B$ and $b$ depend on $n$ values. + +NOTE – Equations 3-1 and 3-2 agree well with the actual characteristics of MOV when $n \geq 10$ , while for $n$ less than 10, $I_p$ deviated from these equations. + +**3.1.6 current de-rating fraction ( $F_I$ ):** Ratio of impulse current peak $I_p(n, \tau)$ to the maximum discharge current $I_{\max}$ . + +$$F_I = I_p(n, \tau) / I_{\max}$$ + +**3.1.7 effective resistance:** Ratio of the rear peak voltage to the applied impulse current peak of the specified waveform, unless otherwise specified, 8/20 impulse current shall be used. + +**3.1.8 effective linear resistance ( $R_V$ ):** Linear component of the effective resistance determined by the high-impulse-current method. + +NOTE – The linear resistance of the MOV may be determined by the high-frequency-signal method, infrared method and high-impulse-current method, but they may give different results. + +**3.1.9 effective non-linear resistance ( $R_Z$ ):** Non-linear component of the effective resistance which can be expressed by equation 3-3 + +$$R_Z = A_1 \cdot I_p^{(\beta-1)} \quad (3-3)$$ + +where: + +$A_1$ is the virtual clamping voltage at 1 A of specified impulse + +$\beta$ is the non-linearity current index + +**3.1.10 endurance at maximum operating temperature:** Property to operate at maximum operating temperature and maximum continuous operating voltage (MCOV) for 1000 h. + +NOTE – Unless otherwise specified, the maximum recommended operating temperature is 85°C. + +**3.1.11 front peak voltage ( $U_F$ ):** Maximum voltage across the MOV occurring at the initial time of an applied impulse current of specified waveform and peak value. The front peak voltage represents a time-dependent modification of the highly non-linear conduction process responsible for varistor action. + +**3.1.12 high (low) voltage varistors:** The varistors of varistor voltage $U_N \geq 82$ V are called high voltage varistors, and those of varistor voltage smaller than 82 V are named low voltage varistors. + +**3.1.13 impulse:** Unidirectional wave of voltage or current without appreciable oscillation. + +Six impulses are used in this Recommendation: current impulse 8/20, 10/350, 10/1000, 2-ms rectangular wave, electrostatic discharge, and 1.2/50-8/20 combination impulse. + +**3.1.14 impulse current peak ( $(I_p(n, \tau))$ ):** Repetitive impulse current peak which can be applied for application numbers ( $n$ ) with impulse width $\tau$ . + +**3.1.15 impulse width ( $\tau$ ):** Normalized impulse duration which is the ratio of the waveform area to the impulse peak, by means of $\tau$ any waveform of impulse can be converted into an equivalent rectangular wave. + +**3.1.16 informative characteristics:** Characteristics of a metal oxide varistor (MOV) which are of significance for applications and should be provided by manufactures, but they are not covered by an + +acceptance inspection programme, for example: V-I characteristics, V-I characteristics of low field region, current peak de-rating curve, temperature de-rating curve. + +**3.1.17 leakage current a.c. ( $I_{La}$ ):** Current passing through the metal oxide varistor (MOV) with the maximum a.c. voltage $U_C$ applied on it, and at a specified temperature, it may be r.m.s value or peak value. + +**3.1.18 leakage current d.c. ( $I_{Ld}$ ):** Current passing through the metal oxide varistor (MOV) with the maximum d.c. voltage $U_{DC}$ applied on it, and at a specified temperature. + +**3.1.19 long (short) duration impulse:** An impulse with an impulse width $\tau \geq 100 \mu\text{s}$ is called a long duration impulse, in contrast, an impulse of $\tau < 100 \mu\text{s}$ is called a short duration impulse. + +NOTE – In this Recommendation, a long (short) duration impulse is denoted by the letter "L" ("S") + +**3.1.20 maximum continuous operating voltage (MCOV) ( $U_C$ ( $U_{DC}$ )):** Maximum a.c. r.m.s. voltage $U_C$ or maximum d.c. voltage $U_{DC}$ which can be applied continuously at a temperature of 25°C. $U_C$ shall be a substantially sinusoidal voltage (less than 5% total harmonic distortion). + +**3.1.21 maximum discharge current ( $I_{max}$ ):** The maximum allowable crest value of impulse current with 8/20 waveform for two applications. + +**3.1.22 metal oxide varistor (MOV):** Component made of ZnO and a few additives whose conductance, at a given temperature, increases rapidly with the voltage increasing over a certain voltage range. It is also known as a voltage-dependent resistor (VDR). + +**3.1.23 nominal discharge current ( $I_n$ ):** The crest value of impulse current with 8/20 waveform that is intended for clamping voltage measurement of the metal oxide varistors (MOVs) for power circuit use. + +**3.1.24 non-linearity current index ( $\beta$ ):** Slope of the volt-ampere characteristic when the effective linear resistance is much smaller than the effective non-linear resistance. It is always less than 1. For the convenience of calculation, equation 3-4 may be used. + +$$\beta = \frac{\lg(U_{cla1}/U_{cla2})}{\lg(I_{p1}/I_{p2})} \quad (3-4)$$ + +NOTE – For most commercially available metal oxide varistors (MOVs), it is considered that the effective linear resistance is much smaller than the effective non-linear resistance when the 8/20 current density $J_p$ is less than 320 A/cm2. + +**3.1.25 rated dissipation power ( $P_m$ ):** Maximum allowable average power dissipation when subjected to the stress of successive impulses and at the temperature of 25°C. + +**3.1.26 rated impulse energy ( $W_m$ ):** Maximum single impulse energy which can be absorbed by the metal oxide varistor (MOV) for a specified waveform. Unless otherwise specified, a 2 ms rectangular current impulse or 10/1000 current impulse shall be used. + +**3.1.27 rear peak voltage ( $U_R$ ):** Maximum voltage across the metal oxide varistor (MOV) occurring at the time behind the front peak with an application of impulse current of specified waveform and sufficient peak values. + +**3.1.28 temperature de-rating curve:** Graphical representation of parameters de-rating against temperature. + +NOTE – Typical parameters are maximum continuous operating voltage $U_C$ ( $U_{DC}$ ), maximum discharge current $I_{max}$ , nominal discharge current $I_n$ , impulse current peak $I_p(n, \tau)$ , rated dissipation $P_m$ , and rated impulse energy $W_m$ . + +**3.1.29 temporary overvoltage (TOV) ( $U_T$ ):** a.c. voltage (r.m.s.) or d.c. voltage that the metal oxide varistor (MOV) can withstand; $U_T$ exceeds the maximum continuous operating voltage $U_C$ or $U_{DC}$ . + +**3.1.30 temporary overvoltage (TOV) withstanding capability:** The specified TOV stress that a metal oxide varistor (MOV) should be capable of withstanding, and evaluated by the energy absorbed by the MOV and element temperature of the MOV under this stress. + +NOTE – This property of the MOV is intended to match the operation of thermal disconnectors of the surge protective devices (SPDs) that use the MOV. + +**3.1.31 unit thickness voltage:** Ratio of varistor voltage $U_N$ to the thickness of the metal oxide varistor MOV element, expressed in "V/mm". + +NOTE – The peak values of long duration impulse and impulse energy that the MOV is able to withstand depend strongly on the unit thickness voltage of the MOV. + +**3.1.32 varistor voltage ( $U_N$ ):** Voltage, at specified d.c. current, used as a reference point in the component characteristic, unless otherwise specified, 1 mA d.c. current shall be used. + +## 3.2 Terms defined in this Recommendation + +None. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|--------------------------------------| +| AVR | Applied Voltage Ratio | +| DSB | Double-Schottky-Barrier | +| EMF | Electromotive Force | +| ESD | Electrostatic Discharge | +| GDT | Gas Discharge Tube | +| LPF | Low Pass Filter | +| LVR | Limiting Voltage Ratio | +| MCOV | Maximum Continuous Operating Voltage | +| MOV | Metal Oxide Varistor | +| PO | Protected Object | +| PS | Power Source | +| PTE | Protected Terminal Equipment | +| SB | Schottky Barrier | +| SMD | Surface Mounting Device | +| SPC | Surge Protective Component | +| SPD | Surge Protective Device | +| TOV | Temporary Overvoltage | +| VDR | Voltage-Dependent Resistor | + +# 5 Conventions + +None. + +# 6 Construction + +## 6.1 Introduction + +A metal oxide varistor (MOV), sometimes simply called a varistor, is a voltage limiting SPC. Generally, the voltage limiting characteristic comes from the use of a ZnO ceramic element, although other compounds like $Sr\ Ti\ O_3$ and $SnO_2$ can be used. + +NOTE – Early documents such as [b-Wang] page 14 and [b-Wang] page 18, referred to the varistor as a "voltage dependent resistor (VDR)", and described the varistor as a "component, whose conductance, at a given temperature, increases rapidly with voltage". Subsequent studies found that during pulse conditions the varistor's conductance decreases with increasing voltage, however the conductance of an MOV is monotonically increasing with current (page 38, [b-Panasonic]). + +## 6.2 Packaging + +Figure 1 shows some commonly used component form factors. Depending on the component terminals, form factors can be classified as leaded disc type (including wire, strap and screw terminal) or leadless type for surface mount technology. + +The ceramic element inside an MOV may be made from either a single-layer disc (see Figure 1 (a)) or multi-layer chip, called a multi-layer varistor (MLV) (see Figure 1 (b)). Sometimes several MOV components may be combined into one package to form an MOV array or multi-unit MOV (see Figure 1 (c)). + +Additionally, there are some special structures for unique applications. For example, a so called "ring shape noise suppression varistor" which is placed on the rotational axis of micro-motors to absorb surge voltages that occur during periods of phase voltage transition of the rotor windings (see Figure 1 (d)). + +![Figure 1 – MOV form factors. (a) Leaded disc MOV: cross-section showing ceramic element (1), silver layer (2), lead wires (3), and insulation (4). (b) Multi-layered varistor (MLV): cross-section showing ceramic layer (1), inner metal layer (2), and exterior metal electrodes (3). (c) Array type: photograph of a multi-terminal component. (d) Ring shape varistor: cross-section showing ceramic element (1) and surface silver layer (2).](0dd5ee731e9d7e34e498b5c926110773_img.jpg) + +(a) Leaded disc MOV + +(b) Multi-layered varistor (MLV) + +(c) Array type + +(d) Ring shape varistor + +① Ceramic element +② Silver layer +③ Lead wires (straps) +④ Insulation + +① Ceramic layer +② Inner metal layer +③ Exterior metal electrodes + +① Ceramic element +② Surface silver layer + +K.128(18)\_F01 + +Figure 1 – MOV form factors. (a) Leaded disc MOV: cross-section showing ceramic element (1), silver layer (2), lead wires (3), and insulation (4). (b) Multi-layered varistor (MLV): cross-section showing ceramic layer (1), inner metal layer (2), and exterior metal electrodes (3). (c) Array type: photograph of a multi-terminal component. (d) Ring shape varistor: cross-section showing ceramic element (1) and surface silver layer (2). + +**Figure 1 – MOV form factors** + +## 6.3 Ceramic element structure + +The nonlinear V-I relationship of an MOV is due to its microstructure. MOVs are made primarily of ZnO powder, to which is added a small quantity of additives (about 10% in weight) such as Bi, Sb, Co, Mn, and others. The powder mix is made into a semiconducting ceramic element with typical ceramic processes. Figure 2 shows an electro-micrograph picture of the ceramic body, from which three substance phases can be found; ZnO crystal grains, grain boundary phase and some minute insulating grains mainly at triple points. + +![A grayscale micrograph of a ceramic microstructure. The image shows large, dark, irregularly shaped grains (labeled 1) separated by lighter, more uniform regions (labeled 2). Small, dark, circular features are scattered throughout the grain boundaries (labeled 3). A scale bar at the bottom right indicates 5 μm. A grayscale bar at the top left is labeled 'Grey' with values 0 and 255.](5f2c99ae08864cf2d5c949947bac2b98_img.jpg) + +A grayscale micrograph of a ceramic microstructure. The image shows large, dark, irregularly shaped grains (labeled 1) separated by lighter, more uniform regions (labeled 2). Small, dark, circular features are scattered throughout the grain boundaries (labeled 3). A scale bar at the bottom right indicates 5 μm. A grayscale bar at the top left is labeled 'Grey' with values 0 and 255. + +- 1 —ZnO crystal grain , +- 2 —grain boundary phase, +- 3 —minute insulating grains + +**Figure 2 – Picture of the microstructure** + +The ZnO grains in MOV ceramics are n-type semiconductor having a resistivity as low as $(0.1 \sim 1)$ $\Omega\text{-cm}$ , which means it is a good conductor. The grains play three major roles in MOV operations: electric conduction, heat conduction, and energy absorption. The average size of the ZnO grains range from less than $10 \mu\text{m}$ to more than $100 \mu\text{m}$ for commonly used MOVs. + +![A schematic diagram of a Double Schottky Barrier (DSB) model. The vertical axis is Energy (E) in eV, and the horizontal axis is Distance (D) in nm. The diagram shows two ZnO grains separated by a thin insulating film of thickness ≈ 1 nm. The energy bands are bent at the interfaces. The conduction band (Ec) and valence band (Ev) are shown. The Fermi level (Ef) is indicated. The potential barrier height (Φo) is shown. The depletion region width (L) is indicated on both sides of the barrier. The diagram is labeled (DSB) model (L ≈ 100nm).](fe753d01ad5fe6cf150018c958173c6d_img.jpg) + +A schematic diagram of a Double Schottky Barrier (DSB) model. The vertical axis is Energy (E) in eV, and the horizontal axis is Distance (D) in nm. The diagram shows two ZnO grains separated by a thin insulating film of thickness ≈ 1 nm. The energy bands are bent at the interfaces. The conduction band (Ec) and valence band (Ev) are shown. The Fermi level (Ef) is indicated. The potential barrier height (Φo) is shown. The depletion region width (L) is indicated on both sides of the barrier. The diagram is labeled (DSB) model (L ≈ 100nm). + +**Figure 3 – Double Schottky Barrier (DSB)** + +At an intimately contact portion of two grains, there is a very thin inter-granular film that is about $1 \text{ nm}$ thick, see Figure 3. Within this film there are a very large number of electrons which are trapped from the adjacent ZnO grains resulting in space charge (or depletion) regions at each side of the $1 \text{ nm}$ -film, hence an electrostatic potential barrier is built up in ZnO surface at each side, which control the current flow through the ceramic body. These types of barriers are Schottky Barriers (SBs) and not PN-junction barriers. The value of electrostatic potential of the SB is typically $3.2 \text{ V}$ to $3.4 \text{ V}$ for a $\text{ZnO-Bi}_2\text{O}_3$ -based varistor, or $1.4 \text{ V}$ for a $\text{ZnO-P}_2\text{O}_5$ -based varistor, which is almost independent of the ceramic formulations and fabricating processes. + +The microstructure of two adjacent ZnO-grains plus their inter-granular film can form a Double-Schottky-Barrier (DSB) resulting in a symmetric V-I characteristic in two directions. This microstructure may be considered as an MOV-cell, or a micro-varistor, and an MOV component can be considered as many MOV-cells connected in series and parallel. + +The DSB model can well describe many important behaviours of MOVs in low current range including high temperature-sensitivity of the non-linear resistance, but the DSB model fails to comprehend high impulse current operation, which is quite insensitive to temperature. A few improved models have been reported, but they lack consensus at the present time. + +## 6.4 Ceramic element as a network + +The MOV's ceramic element may be considered a three-dimensional network with a large number of MOV-cells acting in series-parallel connections between the two electrode layers. Accordingly, the macro-properties of an MOV should be the statistical representation of all MOV-cells inside the network. From this understanding the following points can be deduced: + +In a ceramic block of a given average grain size, the series numbers of MOV-cells, as well as its voltage ratings, are roughly proportional to the thickness of the block. In a ceramic block of a given thickness, the series numbers of MOV-cells, as well as its voltage ratings, are roughly inversely proportional to the average grain size of the block. In a ceramic block, the paralleled numbers of MOV-cells, as well as its current ratings, are roughly proportional to the area of the metal electrode surface on the block. Combining above points, it is concluded that the power and energy handling capabilities of an MOV will be roughly proportional to the volume of its ceramic block. + +Figure 2 shows that the grain size varies from grain to grain, and their physical electrical and thermal properties as well, which result in an uneven distribution of the current density and the temperature rise inside the block during a period of current flowing. + +# 7 Modelling MOV non-linearity + +## 7.1 Nonlinearity index + +### 7.1.1 Introduction + +The nonlinearity index $\alpha$ or $\beta$ coefficients characterize the MOV V-I non-linearity. + +The following two equations express the voltage-current characteristic of an MOV + +$$U = CI^\beta \quad (5)$$ + +$$I = DU^\alpha \quad (6)$$ + +where: + +$I$ – the current that flows through the MOV + +$U$ – the voltage across the MOV at the current $I$ + +$\beta$ – current nonlinearity index + +$\alpha$ – voltage nonlinearity index + +$\alpha = 1/\beta$ + +$C$ and $D$ – constants + +A linear resistor has $\beta=\alpha=1$ . A non-linear resistor that is voltage limiting has $\beta < 1$ , $\alpha > 1$ and a non-linear resistor that is current limiting has $\beta > 1$ , $\alpha < 1$ . + +The nonlinearity index $\alpha$ varies with the MOV body temperature and the MOV current level, but the variation behaviour is very different between low and high current levels owing to the different conduction mechanisms. + +### 7.1.2 Physical meaning of voltage nonlinearity index $\alpha$ + +From equation 6, equation 7 for $\alpha$ can be derived + +$$\alpha = \frac{U/I}{dU/dI} = \frac{R_v}{R_d} \quad (7)$$ + +where: + +static resistance $R_v = U/I$ + +dynamic resistance, or increment resistance $R_d = dU/dI$ + +Equation 7 shows that voltage nonlinearity index $\alpha$ is a ratio of the static resistance to its dynamic resistance. + +### 7.1.3 Geometric meaning of current nonlinearity index $\beta$ + +From equation 5, equation 8 can be derived which signifies the slope of the logarithmic curve $\log U = f(\log I)$ . Equation 9 is the reciprocal of equation 8 + +$$\beta = \frac{\log U_2 - \log U_1}{\log I_2 - \log I_1} = \frac{\log(U_2/U_1)}{\log(I_2/I_1)} \quad (8)$$ + +or + +$$\alpha = \frac{\log(I_2/I_1)}{\log(U_2/U_1)} \quad (9)$$ + +These two equations give an average value of $\alpha$ or $\beta$ in a current range of $[I_2, I_1]$ , usually the DC- $\alpha$ is defined in a current range of [1 mA, 0.1 mA]. Sometimes the current range of $[2I, I]$ is defined, and the $\alpha$ obtained is denoted as " $\alpha_{21}$ ". + +### 7.1.4 Nonlinearity index $\alpha$ variation in standby + +The low current standby operation region of an MOV is temperature sensitive and the $\alpha$ -value decrease dramatically with increasing temperature, see Figure 4. + +![Figure 4: A scatter plot showing the Non-linearity index alpha (Y-axis, ranging from 0 to 80) versus Temperature in degrees Celsius (X-axis, ranging from 0 to 250). The data points show a sharp decrease in alpha as temperature increases, starting from approximately 75 at 25°C and dropping to about 5 at 215°C. The plot is labeled K.128(18)_F04.](26e9c4913991b44e4691f4c4984b7dff_img.jpg) + +| Temperature (°C) | Non-linearity index $\alpha$ | +|------------------|------------------------------| +| 25 | 75 | +| 85 | 42 | +| 115 | 28 | +| 135 | 20 | +| 155 | 14 | +| 215 | 5 | + +Figure 4: A scatter plot showing the Non-linearity index alpha (Y-axis, ranging from 0 to 80) versus Temperature in degrees Celsius (X-axis, ranging from 0 to 250). The data points show a sharp decrease in alpha as temperature increases, starting from approximately 75 at 25°C and dropping to about 5 at 215°C. The plot is labeled K.128(18)\_F04. + +Figure 4 – Example of standby $\alpha$ decreasing with increasing temperature + +The low current region dependency of $\alpha$ is shown in Figure 5. Over the current range shown the $\alpha$ -value continuously rises with current, meaning that the level of nonlinearity will also increase. At some current level the $\alpha$ -value will peak then fall. For MOVs with a $U_{1\text{mA}} \geq 75 \text{ V}$ , their highest $\alpha$ -value in low DC region ranges between 20 to 100. + +![Figure 5: A scatter plot showing the nonlinearity index alpha(I, 2I) increasing with increasing current. The x-axis is log(I) in microamperes (uA), ranging from 0.5 to 3.5. The y-axis is alpha(I, 2I), ranging from 40 to 110. The data points show a continuous upward trend.](8ccbc9fa77bf60ba0ca0b79dec8681b8_img.jpg) + +| log(I) (uA) | $\alpha(I, 2I)$ | +|-------------|-----------------| +| 0.7 | 41 | +| 1.0 | 43 | +| 1.3 | 47 | +| 1.7 | 53 | +| 2.0 | 58 | +| 2.3 | 64 | +| 2.7 | 75 | +| 3.0 | 86 | +| 3.3 | 101 | + +Figure 5: A scatter plot showing the nonlinearity index alpha(I, 2I) increasing with increasing current. The x-axis is log(I) in microamperes (uA), ranging from 0.5 to 3.5. The y-axis is alpha(I, 2I), ranging from 40 to 110. The data points show a continuous upward trend. + +Figure 5 – Example of $\alpha(I, 2I)$ increasing with increasing current + +### 7.1.5 Nonlinearity index $\alpha$ variation in voltage limiting + +Figure 6 shows that the index $\alpha_{21}(I, 2I)$ of a $\phi 14 \text{ mm}$ , $U_{1\text{mA}}=738 \text{ V}$ MOV falls as the 8/20 current peak current increases. The MOV limiting voltage $U$ increases with increasing current. Example spot values are for $I=200 \text{ A}$ , $U=1.2 \text{ kV}$ and $\alpha_{21}=60$ , while for $I=8 \text{ kA}$ , $U=2.6 \text{ kV}$ and $\alpha_{21}=8$ . Generally, the MOV's lowest value of $\alpha_{21}$ at its maximum rated 8/20 current falls towards 2 to 3. + +![Figure 6: A dual-axis plot showing MOV voltage (U) and alpha_21 variation with 8/20 peak current. The x-axis is log(I) in Amperes (A), ranging from 2.2 to 4.0. The left y-axis is U (V), ranging from 1000 to 2800. The right y-axis is alpha_21, ranging from 0 to 70. The U curve increases with log(I), while the alpha_21 curve decreases.](df7cb4ea9bd6c3f445f3e264773b125f_img.jpg) + +| log(I) (A) | U (V) | $\alpha_{21}$ | +|------------|-------|---------------| +| 2.3 | 1200 | 60 | +| 2.5 | 1400 | 40 | +| 2.7 | 1550 | 25 | +| 3.0 | 1750 | 15 | +| 3.3 | 2000 | 10 | +| 3.6 | 2250 | 8 | +| 3.8 | 2400 | 8 | +| 3.9 | 2600 | 8 | + +Figure 6: A dual-axis plot showing MOV voltage (U) and alpha\_21 variation with 8/20 peak current. The x-axis is log(I) in Amperes (A), ranging from 2.2 to 4.0. The left y-axis is U (V), ranging from 1000 to 2800. The right y-axis is alpha\_21, ranging from 0 to 70. The U curve increases with log(I), while the alpha\_21 curve decreases. + +Figure 6 – MOV voltage ( $U$ ) and $\alpha_{21}$ variation with 8/20 peak current (200 A to 8 kA) + +## 7.2 Resistance formula + +### 7.2.1 General + +[b-Panasonic], page 38, first reported a resistance formula of an MOV, from which a set of V-I characteristic formulas can be easily deduced. The formulas have been successfully used for solving + +engineering MOV and MOV-type surge protective device (SPD) calculation problems, owing to the following advantages. + +- Applicable to DC, AC, and impulse operation of the MOV. +- Applicable to a wider current range of greater than two decades. +- Has sufficient accuracy, usually 3%. +- The test and calculation steps to determine formula's constants are easy to do. + +### 7.2.2 MOV resistance R measurement aspects + +The MOV resistance $R$ is the quotient of the MOV measured voltage to the measured current value through it. Measurements should observe the following: + +- For DC and AC power frequency measurements, there is time delay ( $\Delta t$ ) after the tested MOV being powered before readings stabilise. The time $\Delta t$ varies mainly with the current density. Generally, measurements should be made after a $\Delta t$ of 0.1 s. +- For DC and AC power frequency measurements, some polarization of the current and voltage values should be taken into account. The polarization is dependent on current density. To average out the polarisation, the average of the plus and minus measurements should be used. +- For impulse and AC power frequency measurements, the voltage and current measurements should be peak values, but these values may not occur at the same instant of time. + +### 7.2.3 MOV resistance formula + +Equation 10 shows the resistance formula that can be used to predict the MOV V-I characteristic over a wide current range. + +$$\log R = A_0 + A_1 \log I + A_2 (\log I)^2 \quad (10)$$ + +Where: $A_0$ , $A_1$ and $A_2$ are constants that are dependent on the characterised MOV part number. The formula shows that the resistance of an MOV varies with the current in a monotonic manner. + +### 7.2.4 V-I characteristic from the MOV resistance formula + +Equation 10 may be modified to plot the V-I characteristic as follows: + +Add $\log I$ to both sides of equation 6 + +$$\log R + \log I = A_0 + (1 + A_1) \log I + A_2 (\log I)^2 \quad (11)$$ + +The product of $R$ and $I$ is the varistor voltage $U$ giving: + +$$\log U = A_0 + \log I (1 + A_1 + A_2 \log I) \quad (12)$$ + +Raising both sides to the power of 10 and substituting $B = 1 + A_1 + A_2 \log I$ gives: + +$$U = 10^{A_0} I^B \quad (13)$$ + +The $B$ factor is not a constant but dependent on $\log I$ . + +A similar treatment can give the I-V equation 14: + +$$I = 10^y \quad (14)$$ + +$$y = \frac{-(1 + A_1) + \sqrt{(1 + A_1)^2 + 4A_2 \cdot \log(U/10^{A_0})}}{2A_2}$$ + +Where + +Further manipulation can give the voltage ratio, $k_v$ , equation, which is used for comparison purposes. + +$$k_v = \frac{10^{A_0}}{U_1} \times I^B \quad (15)$$ + +Again $B = 1 + A_1 + A_2 \log I$ and $U_1$ refers to the varistor voltage of the MOV + +The double-current index $\alpha_{2I}$ can be expressed as + +$$\alpha_{2I} = \frac{1}{(B_I + (0.301 + \log I)A_2)} \quad (16)$$ + +where: + +$B_I$ is the $B$ value at the given current $I$ + +## 7.3 MOV V-I characteristic graphs + +### 7.3.1 Traditional MOV V-I graphs + +A V-I characteristic can be described by mathematical equations (formulas) or a list of values or a graph of voltage against current. Until the MOV resistance equation and its derived V-I formula were introduced, there was not an equation that could describe the V-I relationship of an MOV over a wide range of current values. + +Commonly published V-I graphs are typically generic and do not illustrate the MOV characteristics for DC, AC or impulse source types. Figure 7 [b-Wu] and Figure 8 (page 39, [b-Panasonic]) are two examples of such MOV V-I graphs. + +![Figure 7: Common example of an MOV V-I graph. The graph plots Voltage (V) on the y-axis (logarithmic scale from 10 to 1000) against Current (A) on the x-axis (logarithmic scale from 10^-8 to 10^4). The graph is divided into three regions: LEAKAGE REGION (low current), NORMAL VARISTOR OPERATION (middle current), and UPTURN REGION (high current). The curve is labeled I = kV^alpha. A slope indicator shows SLOPE = 1/alpha. Resistance values R = 10^5 Ohm and R = 10 Ohm are indicated. The graph is for a TYPICAL V130LA20A MOV. Source: K.128(18)_F07.](aa2c9d5694eb4659b1e5712b70e244e2_img.jpg) + +The figure is a log-log plot of Voltage (V) versus Current (A) for a Metal Oxide Varistor (MOV). The y-axis ranges from 10 to 1000 V, and the x-axis ranges from $10^{-8}$ to $10^4$ A. The curve is divided into three distinct regions: + +- LEAKAGE REGION:** At very low currents (below $10^{-6}$ A), the voltage increases sharply. A dashed line indicates a resistance of $R = 10^5 \Omega$ . +- NORMAL VARISTOR OPERATION:** The middle region where the voltage increases more gradually with current. A solid line represents the characteristic $I = kV^\alpha$ . A tangent line segment indicates a slope of $\frac{1}{\alpha}$ . +- UPTURN REGION:** At high currents (above $10^2$ A), the voltage increases sharply again. A dashed line indicates a resistance of $R = 10 \Omega$ . + +The graph is labeled "(TYPICAL V130LA20A)" and the source code "K.128(18)\_F07" is shown in the bottom right corner. + +Figure 7: Common example of an MOV V-I graph. The graph plots Voltage (V) on the y-axis (logarithmic scale from 10 to 1000) against Current (A) on the x-axis (logarithmic scale from 10^-8 to 10^4). The graph is divided into three regions: LEAKAGE REGION (low current), NORMAL VARISTOR OPERATION (middle current), and UPTURN REGION (high current). The curve is labeled I = kV^alpha. A slope indicator shows SLOPE = 1/alpha. Resistance values R = 10^5 Ohm and R = 10 Ohm are indicated. The graph is for a TYPICAL V130LA20A MOV. Source: K.128(18)\_F07. + +Figure 7 – Common example of an MOV V-I graph cited in many papers + +![Figure 8: A log-log plot of Voltage (V) versus Current (I) for a MOV. The y-axis (V) ranges from 50 to 5000, and the x-axis (I) ranges from 10^-5 to 10^4 A. The plot is divided into two regions: 'A' (leakage current) and 'B' (limiting voltage). Region 'A' is a horizontal line at approximately 400 V for currents below 10^-3 A. Region 'B' is a curve starting at 10^-3 A and 400 V, rising to about 2000 V at 10^4 A. The curve is labeled 'B' and has a small arrow pointing to it from the label 'B'.](5ed9189841659dfb01f809b8e3b21f74_img.jpg) + +Figure 8: A log-log plot of Voltage (V) versus Current (I) for a MOV. The y-axis (V) ranges from 50 to 5000, and the x-axis (I) ranges from 10^-5 to 10^4 A. The plot is divided into two regions: 'A' (leakage current) and 'B' (limiting voltage). Region 'A' is a horizontal line at approximately 400 V for currents below 10^-3 A. Region 'B' is a curve starting at 10^-3 A and 400 V, rising to about 2000 V at 10^4 A. The curve is labeled 'B' and has a small arrow pointing to it from the label 'B'. + +**Figure 8 – Data sheet example with "A" leakage current and "B" limiting voltage regions marked** + +Figure 7 shows a single smooth V-I characteristic over the entire current range. This is not reality as there should be separate segments for DC, AC and impulse current operation. Equation 6, $I = DU^\alpha$ , gives a smooth MOV V-I characteristic, but it cannot represent the characteristic over a large range of current. One reason is $\alpha$ varies, a range of 20 to 5 can occur. Also, the note that "R=1 $\Omega$ to 10 $\Omega$ " is probably unrealistic and " $R < 0.1 \Omega$ " would be more reasonable. + +Figure 8 splits the characteristic into "A" for DC conditions and "B" for AC and impulse conditions. However, in the "B" part, there is a lower limit value for an 8/20 impulse current peak, due to the capacitance of the MOV. Hence, the lower "B" range limit of 1 mA is unlikely as an 8/20 impulse current value. + +### 7.3.2 Segmented DC, AC and impulse MOV V-I characteristics + +See [b-Xu]. + +Because the operating current range of an MOV can cover about 10 decades, there really needs to be three V-I characteristics: at low currents a DC characteristic, at medium current an AC characteristic and at high currents an impulse current characteristic. Figure 9 is an example of these three characteristics. + +The V-I characteristics are normalised to the 1 mA MOV voltage by using $k_v$ equation 11. The actual equation 11 values are: + +DC characteristic: ( $I=10 \mu\text{A}$ to $10 \text{ mA}$ ), $k_v=0.781I^B$ with $B=0.06372-0.00866\log I$ + +AC characteristic: ( $I=3 \text{ mA}$ to $10 \text{ A}$ ), $k_v=1.081I^B$ with $B=0.01592+0.0003\log I$ + +Impulse characteristic: ( $I=200 \text{ A}$ to $20 \text{ kA}$ ), $k_v=2.297I^B$ with $B=-0.19552+0.04671\log I$ + +The values of non-linearity index $\alpha$ for the DC and AC characteristics are shown in Figure 9. + +![Figure 9: MOV DC, AC and impulse characteristics. A log-log plot showing Voltage ratio U/U 1mA vs Log I. The plot includes three curves: DC (black squares), AC 50Hz (red circles), and 8/20 impulse (green triangles).](60e9207be66a64332619bb4b667fe67b_img.jpg) + +The graph shows the voltage ratio $U/U_{1\text{mA}}$ on the y-axis (ranging from 0.8 to 2.2) against the logarithm of current $\text{Log } I$ on the x-axis (ranging from -5 to 4). The x-axis is labeled with current values: $(10\ \mu\text{A})$ , $(100\ \mu\text{A})$ , $(1\ \text{mA})$ , $(10\ \text{mA})$ , $(100\ \text{mA})$ , $(1\ \text{A})$ , $(10\ \text{A})$ , $(100\ \text{A})$ , $(1\ \text{kA})$ , $(10\ \text{kA})$ . + +Three characteristics are plotted: + +- DC** (black squares): $\alpha = 26 \text{ to } 100$ . The curve starts at approximately $(-5, 0.85)$ and levels off at $(-2, 1.0)$ . +- AC 50Hz** (red circles): $\alpha = 61 \text{ to } 55$ . The curve starts at approximately $(-2, 1.1)$ and increases to $(1, 1.25)$ . +- 8/20 impulse** (green triangles): The curve starts at approximately $(2, 1.4)$ and increases sharply to $(4, 2.1)$ . + +K.128(18)\_F09 + +Figure 9: MOV DC, AC and impulse characteristics. A log-log plot showing Voltage ratio U/U 1mA vs Log I. The plot includes three curves: DC (black squares), AC 50Hz (red circles), and 8/20 impulse (green triangles). + +**Figure 9 – MOV DC, AC and impulse characteristics** + +The MOV impulse characteristic will depend on the type of impulse used for the characterisation. Figure 9 shows an 8/20 impulse characteristic. Figure 10 is an example of how the characteristic varies for a 2 ms pulse and impulses of 1/5, 4/10 and 8/20. The Figure also shows how the peak voltage increases as the impulse current front time decreases for a given peak current. + +![Figure 10: Example impulse V-I characteristics for various impulse waveshapes. The graph plots Peak voltage normalised to 8/20, 10 kA voltage (Y-axis, 0 to 1.5) against Peak impulse current — A (X-axis, logarithmic scale from 10^1 to 10^6). Four curves are shown: '2 ms pulse', '8/20', '1/5', and '4/10'. The 4/10 curve is the steepest, followed by 1/5, and then 8/20. The '2 ms pulse' curve is at the lower current end.](0f79a59f3766fc341ff688a23692c1d9_img.jpg) + +The graph shows the relationship between peak voltage and peak impulse current for different waveshapes. The Y-axis is 'Peak voltage normalised to 8/20, 10 kA voltage' ranging from 0 to 1.5. The X-axis is 'Peak impulse current — A' on a logarithmic scale from $10^1$ to $10^6$ . Four curves are plotted: + - **4/10**: The steepest curve, reaching the highest normalized voltage at high currents. + - **1/5**: A steep curve between 4/10 and 8/20. + - **8/20**: A less steep curve. + - **2 ms pulse**: A curve starting at lower current values (around $10^2$ A) and lower normalized voltage. + +Figure 10: Example impulse V-I characteristics for various impulse waveshapes. The graph plots Peak voltage normalised to 8/20, 10 kA voltage (Y-axis, 0 to 1.5) against Peak impulse current — A (X-axis, logarithmic scale from 10^1 to 10^6). Four curves are shown: '2 ms pulse', '8/20', '1/5', and '4/10'. The 4/10 curve is the steepest, followed by 1/5, and then 8/20. The '2 ms pulse' curve is at the lower current end. + +**Figure 10 – Example impulse V-I characteristics for various impulse waveshapes** + +## 7.4 Other non-linear resistance effects + +Unlike linear resistors the MOV shows peak displacement and negative dynamic resistance under particular conditions. + +Negative dynamic resistance is when the voltage varies in an opposite direction to that of the current ( $-dR = -du/di$ or $du/-di$ ), see Figure 11. Peak displacement is when the voltage peak occurs at a different time point from that of the current peak, see Figure 12. + +![Figure 11: MOV voltages, U1, U2, U3 and U4, during 8/20 impulse currents of Ip1 < Ip2 < Ip3 < Ip4. The graph plots Voltage ratio (Y-axis, 0.96 to 1.32) against Time in microseconds (X-axis, 0 to 10). Four curves are shown: U1 (black squares) decays from 1.00 to ~0.96; U2 (red circles) is constant at 1.04; U3 (blue triangles) peaks at U3m (~1.15) at 6.3 μs; U4 (teal inverted triangles) peaks at U4m (~1.30) at 7.5 μs. Arrows point to the peaks of U3 and U4.](9ce50bc10864dc86e1cdee4be08f1897_img.jpg) + +| Time (μs) | U1 | U2 | U3 | U4 | +|-----------|------|------|------|------| +| 1 | 1.00 | 1.04 | 1.10 | 1.20 | +| 2 | 0.99 | 1.04 | 1.12 | 1.23 | +| 3 | 0.98 | 1.04 | 1.14 | 1.26 | +| 4 | 0.97 | 1.04 | 1.15 | 1.28 | +| 5 | 0.96 | 1.04 | 1.15 | 1.29 | +| 6 | 0.96 | 1.04 | 1.15 | 1.30 | +| 7 | 0.96 | 1.04 | 1.15 | 1.30 | +| 8 | 0.96 | 1.04 | 1.14 | 1.29 | +| 9 | 0.96 | 1.04 | 1.13 | 1.27 | +| 10 | 0.96 | 1.04 | 1.12 | 1.25 | + +Figure 11: MOV voltages, U1, U2, U3 and U4, during 8/20 impulse currents of Ip1 < Ip2 < Ip3 < Ip4. The graph plots Voltage ratio (Y-axis, 0.96 to 1.32) against Time in microseconds (X-axis, 0 to 10). Four curves are shown: U1 (black squares) decays from 1.00 to ~0.96; U2 (red circles) is constant at 1.04; U3 (blue triangles) peaks at U3m (~1.15) at 6.3 μs; U4 (teal inverted triangles) peaks at U4m (~1.30) at 7.5 μs. Arrows point to the peaks of U3 and U4. + +Figure 11 – MOV voltages, $U_1$ , $U_2$ , $U_3$ and $U_4$ , during 8/20 impulse currents of $I_{p1} < I_{p2} < I_{p3} < I_{p4}$ + +Figure 11 shows four voltage plots ( $U_1$ , $U_2$ , $U_3$ and $U_4$ ) of the same MOV which was subjected to a stepped 8/20 impulse current with the peak values of $I_{p1} < I_{p2} < I_{p3} < I_{p4}$ . The MOV voltage was sampled in 1 $\mu\text{s}$ steps over the time range of 1 $\mu\text{s}$ to 10 $\mu\text{s}$ . The MOV voltage waveforms varied in three ways depending on the current peaks. In Figure 11 the MOV voltage is normalised to $U_1$ at 1 $\mu\text{s}$ . + +- The lowest current MOV voltage $U_1$ shows a continuous decaying voltage waveform which is a negative incremental dynamic resistance characteristic. +- During the second current step, $I_{p2}$ , the MOV voltage $U_2$ shows a constant voltage level, which is a zero-incremental dynamic resistance characteristic. +- At the two highest current steps the MOV voltages $U_3$ and $U_4$ show a voltage increase at first till reaching a peak value ( $U_{3m}$ and $U_{4m}$ ) followed by a decrease. + +This 8/20 impulse test behaviour implies three things: + +- 1) Peak displacement – the 8/20 impulse current peak is at the 10 $\mu\text{s}$ but the MOV voltage peak occurs before, for $U_{3m}$ this happened at 6.3 $\mu\text{s}$ and for $U_{4m}$ the peak happened at 7.5 $\mu\text{s}$ . +- 2) Negative increment resistance – in the time interval between voltage peak and current peak, the voltage value going down while the current going up. +- 3) The MOV voltage peak time moved towards current peak time as the peak current increased (comparing the positions of $U_{3m}$ and $U_{4m}$ ). + +![Figure 12: A line graph plotting 'Normalised voltage and current' on the y-axis (from 0.0 to 1.0) against 'Time — ms' on the x-axis (from 0 to 10). Two curves are shown: 'Voltage' (black line with square markers) and 'Current' (red line with circular markers). The voltage curve peaks at 1.0 at time t = 5 ms. The current curve peaks at 1.0 at time t = 6.6 ms. The time difference between these peaks is labeled as Δt. A label '63.3%' points to a value on the rising edge of the current curve at t = 5 ms. The legend at the bottom identifies the black squares as Voltage and red circles as Current. Reference code K.128(18)_F12 is in the bottom right.](645bea0b27d63e4a9a300af5793ae7d2_img.jpg) + +Figure 12: A line graph plotting 'Normalised voltage and current' on the y-axis (from 0.0 to 1.0) against 'Time — ms' on the x-axis (from 0 to 10). Two curves are shown: 'Voltage' (black line with square markers) and 'Current' (red line with circular markers). The voltage curve peaks at 1.0 at time t = 5 ms. The current curve peaks at 1.0 at time t = 6.6 ms. The time difference between these peaks is labeled as Δt. A label '63.3%' points to a value on the rising edge of the current curve at t = 5 ms. The legend at the bottom identifies the black squares as Voltage and red circles as Current. Reference code K.128(18)\_F12 is in the bottom right. + +**Figure 12 – Normalised MOV voltage and current under AC conditions with voltage source $U_s$** + +Figure 12 for AC conditions shows similar MOV behaviours to the impulse conditions in Figure 11. + +- Peak displacement – Current peak occurs later than voltage peak by a time $\Delta t$ . +- Negative dynamic resistance during the time interval $\Delta t$ . +- Current waveform distortion – current waveform is no longer a sine wave. The current waveform is asymmetric with a rising duration being longer than its falling duration. + +These behaviours are due to the MOV resistance non-linearity and are mathematically explained in Appendix I. + +# 8 Impedance properties and equivalent circuit + +## 8.1 General + +Like other electronic components, the behaviour of an MOV in electrical circuits can be represented by its equivalent circuit model. The equivalent circuit model used will depend on the application being simulated. The model showed in Figure 13 is applicable for DC and AC circuit analysis, while the Figure 14 model is applicable for impulse circuit analysis. + +![Figure 13: Equivalent MOV circuit model. A schematic diagram showing a parallel circuit with three branches. The input current I splits into three paths. The first path on the left contains a capacitor labeled C_V with current I_V. The middle path contains a non-linear resistor (varistor symbol) labeled R_V with current I_RV and voltage U across it. The third path on the right contains a resistor labeled R_ins. The circuit is grounded at the bottom. Reference code K.128(18)_F13 is at the bottom.](e7c6a6e4c3047dac05a3b92e396e9794_img.jpg) + +Figure 13: Equivalent MOV circuit model. A schematic diagram showing a parallel circuit with three branches. The input current I splits into three paths. The first path on the left contains a capacitor labeled C\_V with current I\_V. The middle path contains a non-linear resistor (varistor symbol) labeled R\_V with current I\_RV and voltage U across it. The third path on the right contains a resistor labeled R\_ins. The circuit is grounded at the bottom. Reference code K.128(18)\_F13 is at the bottom. + +**Figure 13 – Equivalent MOV circuit model for impulse analysis** + +![Circuit diagram of a MOV equivalent model. It shows an inductor L_v in series with a parallel combination of a capacitor C_v and a non-linear resistor R_v (labeled with voltage U). This parallel block is in series with a linear resistor R_G. The diagram is labeled K.128(18)_F14.](cbdfdade780e677eb1c1aef3081ce9ef_img.jpg) + +Circuit diagram of a MOV equivalent model. It shows an inductor L\_v in series with a parallel combination of a capacitor C\_v and a non-linear resistor R\_v (labeled with voltage U). This parallel block is in series with a linear resistor R\_G. The diagram is labeled K.128(18)\_F14. + +**Figure 14 – Example photograph of surface temperature distribution together with spot temperatures (°C) for a bare ceramic element** + +The components of Figure 13 and Figure 14 are discussed in following clauses. + +## 8.2 Non-linear resistance $R_v$ + +$R_v$ represents the MOV non-linear resistance which varies from a very low value at high currents to a value approaching infinity at very low currents. When an applied voltage on the MOV is far below its $U_{1\text{mA}}$ , the $R_v$ value approaches infinity. In this case $R_{\text{ins}}$ is the dominant resistance and the MOV can be considered as a linear high value resistor. At the opposite end of the current range, when a high value of impulse current is conducted, $R_v$ approaches zero and the MOV can be regarded as a low value linear resistor. + +## 8.3 Leakage resistance $R_{\text{ins}}$ + +$R_{\text{ins}}$ is the net linear resistance of parallel components of volume insulation resistance and side surface insulation resistance. For quality MOVs, the $R_{\text{ins}}$ value is much higher than the standby operation value of $R_v$ and so can be omitted. However, $R_{\text{ins}}$ might be included in situations when the MOV is exposed to a wet environment that could result in the side surface leakage current to increase steadily with time. + +## 8.4 Capacitance $C_v$ + +As covered in clause 6.3, the MOV-cell consists of a grain boundary layer (insulator) being sandwiched between two ZnO grains (conductor) which forms a capacitor. The actual MOV capacitance, $C_v$ , is the result of the MOV ceramic element being a network of many capacitor-cells connected in series and in parallel. The MOV capacitance, $C_v$ , will be inversely proportional to varistor voltage and proportional to the ceramic element area rather than the thickness of its ceramic body. + +## 8.5 Linear resistance $R_G$ + +The high current resistance, $R_G$ , consists mainly of ZnO grain resistances, the ceramic surface to silver layer to metal termination contact resistance and the terminal lead resistance. Normally $R_G$ is quite low, in the order of milliohms, but needs to be taken into account at high impulse currents when the non-linear resistance $R_v$ approaches the $R_G$ value. + +## 8.6 Inductance $L_v$ + +The MOV's inductance, $L_v$ , increases the MOV impulse limiting voltage at high rates of current change, $di/dt$ , by $L_v \times (di/dt)$ . The inductance of MOV's ceramic element is extremely small. The main component of $L_v$ is the terminal lead inductance, which is about 1 nH/mm. For general lightning + +protection applications, the $L_V$ voltage of a standard leaded type MOV is not a major factor. Including $L_V$ should only be considered when the $di/dt$ of the specified impulse current is far greater than that of the rated 8/20 impulse. The external circuit wiring connections to the MOV can represent much higher values of series inductance and their $L \times (di/dt)$ contribution can greatly increase the net in-circuit limiting voltage. + +# 9 Ceramic element current and temperature distribution + +## 9.1 Introduction + +An ideal MOV would have a uniform current density in the ceramic element, resulting from a uniform material resistivity. However, such a result would require a uniform microstructure with identical grains and grain-boundaries in dimension, orientation, chemistry, thermal and electrical properties. Unfortunately, limitations of current ceramic processes lead to an inhomogeneous microstructure of the ceramic element, and therefore, the resistivity variations, resulting in uneven current distribution inside the ceramic element. + +Uneven current distribution causes an uneven temperature distribution and lowers almost all properties of the MOV. Improving the uniformity of the material forming the MOV ceramic element is a continuous challenge for manufacturers. + +There are two common methods used to evaluate the uniformity of microstructure: "photograph method" and "spot electrode method". + +![Figure 15: Example photograph of surface temperature distribution together with spot temperatures (°C) for a bare ceramic element. The image shows a thermal map of a rectangular ceramic element with a grid of temperature readings overlaid. The temperatures range from 170.5°C to 199.2°C, with a color scale from blue (cooler) to red (hotter).](2bb33687a0af0373c35b56f023a2a1d4_img.jpg) + +| | | | | | | +|-------|-------|-------|-------|-------|-------| +| 170.5 | 185.8 | 186.9 | 183.6 | 181.1 | 167.8 | +| 179.0 | 191.6 | 194.0 | 193.5 | 191.2 | 184.7 | +| 185.8 | 194.4 | 197.1 | 195.9 | 191.3 | 186.3 | +| 191.1 | 196.7 | 199.2 | 197.6 | 191.3 | 186.0 | +| 193.4 | 196.8 | 198.2 | 197.6 | 191.0 | 185.7 | +| 192.5 | 194.8 | 194.4 | 193.0 | 190.0 | 184.9 | +| 189.4 | 193.4 | 192.7 | 191.5 | 189.4 | 182.5 | +| 171.3 | 187.5 | 187.7 | 186.6 | 184.0 | 170.6 | + +Figure 15: Example photograph of surface temperature distribution together with spot temperatures (°C) for a bare ceramic element. The image shows a thermal map of a rectangular ceramic element with a grid of temperature readings overlaid. The temperatures range from 170.5°C to 199.2°C, with a color scale from blue (cooler) to red (hotter). + +**Figure 15 – Example photograph of surface temperature distribution together with spot temperatures (°C) for a bare ceramic element** + +The photograph method is used to check bare discs (without insulation coating). The photograph in Figure 15 was taken after the bare disc had been exposed to a power frequency source for a while. In order to measure the degree of un-uniformity, a parameter of "non-uniformity factor ( $F_U$ )" is defined: + +$$F_U = \frac{T_{\max} - T_{\min}}{T_{AV}} \times 100\% \quad (17)$$ + +Where: $T_{\max}$ , $T_{\min}$ , and $T_{AV}$ refer to the highest, lowest and average temperature respectively on the surface. + +![Figure 16: Diagram of a ceramic element showing a grid of spot electrodes on one side and a full electrode on the other. The top view shows a 5x5 grid of circular spot electrodes with diameter 'd' and center-to-center spacing 'D'. The side view shows the ceramic thickness 'δ' and the spot electrode diameter 'd'.](b8e33e88baf855d3881d2f32fb17b60a_img.jpg) + +Figure 16: Diagram of a ceramic element showing a grid of spot electrodes on one side and a full electrode on the other. The top view shows a 5x5 grid of circular spot electrodes with diameter 'd' and center-to-center spacing 'D'. The side view shows the ceramic thickness 'δ' and the spot electrode diameter 'd'. + +**Figure 16 – Ceramic element with full electrode on one side and spot electrode on other side** + +The spot electrode, usually silver paste electrode, is applied on one surface of the ceramic element, while the other surface is full electrode, see Figure 16. The gap "d" between two spot electrodes is made to be not less than the ceramic element thickness $\delta$ . Then voltage measurement at a specified current (say 10 $\mu\text{A}$ ) is made between each spot and the full electrode. At last the voltage un-uniformity factor ( $F_U$ ) shall be calculated by replacing the temperature with the voltage in equation 17. + +## 9.2 Thermal properties + +The capabilities of an MOV to withstand surge impulse stresses, temporary overvoltage (TOV)-stresses, and temperature-voltage stresses, are closely connected with its thermal properties. Well-known electrical analysis techniques and parameters such as Ohm's law, capacitance, resistance (conductance), charge, voltage and current can be used for in equivalent form for thermal Ohm's law, specific heat capacity, thermal conductivity, and temperature. The mechanical coefficient of thermal expansion also needs to be considered. + +### 9.2.1 Thermal Ohm's law + +If an object ( $O_{bj}$ ), as shown in Figure 17, is considered as an electric conductor, the electrical parameters will conform with the electrical Ohm's law, equation 18; while if it is considered as a thermal conductor, the thermal parameters will conform with the thermal Ohm's law, equation 19. + +![Figure 17: Diagram of a conducting block showing electrical and thermal relationships. The block has length 'L', cross-sectional area 'S', and thermal conductivity 'σ' and permittivity 'λ'. The left face is at potential 'U_B' and temperature 'T_B'. The right face is at potential 'U_A' and temperature 'T_A'. Current 'I' and thermal flux 'Φ' are shown flowing from left to right.](83db47f9541df5f9be73289497eaae90_img.jpg) + +Figure 17: Diagram of a conducting block showing electrical and thermal relationships. The block has length 'L', cross-sectional area 'S', and thermal conductivity 'σ' and permittivity 'λ'. The left face is at potential 'U\_B' and temperature 'T\_B'. The right face is at potential 'U\_A' and temperature 'T\_A'. Current 'I' and thermal flux 'Φ' are shown flowing from left to right. + +**Figure 17 – Electrical and thermal relationships for a conducting block** + +$$I = \sigma \cdot \frac{S}{l} \cdot (U_A - U_B) \text{ (Electric Ohm's law)} \quad (18)$$ + +where: + +$I$ = current + +$\sigma$ = electric conductivity (A/V-cm) + +$S$ = area + +$l$ = length + +$U$ = voltage + +$$\Phi = \lambda \cdot \frac{S}{l} \cdot (T_A - T_B) \text{ (Thermal Ohm's law)} \quad (19)$$ + +where: + +$\Phi$ = heat flow (J/s) + +$\lambda$ = thermal conductivity (W/K-cm) + +$S$ = area + +$l$ = length + +$T$ = temperature + +### 9.2.2 Specific heat capacity: $c \approx 0.84 \text{ J/g-K} \approx 4.54 \text{ J/cm}^3$ + +It takes 0.84 J of heat energy to raise the temperature of one gram of MOV ceramic by 1 degree, or 4.54 J per one $\text{cm}^3$ in volume (density 5.4 g/ $\text{cm}^3$ ). This parameter, is used to calculate the temperature rise of an MOV ceramic element as a result of a current impulse or vice versa. + +### 9.2.3 Thermal conductivity: $\lambda \approx 0.057 \text{ W/cm-K} = 0.057 \text{ J/cm-K-s}$ + +Thermal conductivity $\lambda$ is a material constant, which for MOV ceramic elements is roughly 0.057 J/cm-K-s, about 1.4% of that of copper. Such poor conductivity is one of the major causes responsible for an MOV to catch fire when thermal breakdown occurs. + +### 9.2.4 Coefficient of thermal expansion + +MOV ceramics has a small value of coefficient of thermal expansion, which is roughly $3 \times 10^{-6}/\text{K}$ , about 1/5 of that of copper, therefore proper design coordination between an MOV ceramic element and its copper electrode is needed. + +### 9.2.5 Current concentration (hot spotting) + +Current concentration signifies a dynamic process of the interaction between electric effects and thermal effects in MOV bulk. This interaction shown below can be regenerative with condition 5 becoming the new condition 1: + +- 1) Hot spot heat generation is greater than the heat dissipated. +- 2) Temperature increases. +- 3) MOV resistance reduces. +- 4) Higher current density due to more current from power source and hogging current from higher resistance areas. +- 5) Temperature further increases. + +There are two outcomes here; a thermally stable condition with the generated heat equalling the dissipated heat or thermal runaway because the heat dissipation capability is less than the heat generation. + +Factors effecting this process are: + +- Level of ceramic element inhomogeneity. +- Duration of impulse current or TOV stress – longer durations increase current concentration. +- MOV temperature coefficient of resistance. +- Non-linearity ( $\alpha$ -value) – higher $\alpha$ -value increases current concentration. +- Geometric shape and dimensions of the MOV – larger size and ratio of area to thickness increases current concentration. +- Voltage supply source impedance – low values increases current concentration. + +### 9.2.6 Thermal stability and thermal breakdown + +When current concentration occurs, there are two possible outcomes; thermal stability or thermal runaway. If an MOV has a fixed voltage $U_{ap}$ applied and is in an ambient temperature of $T_a$ , the outcome MOV depends mainly on the temperature, $T$ , relationship between the MOV generated power $P=f(T)$ and dissipated power $Q=f(T)$ capability as shown in Figure 18 [b-Ding]. + +![Figure 18: A graph showing Generated (P) and dissipated (Q) power versus temperature (T). The y-axis is labeled 'P, Q (W)' and the x-axis is labeled 'T (°C)'. The graph shows two curves: a straight line labeled 'Q' representing dissipated power, and a curve labeled 'P' representing generated power. The line Q starts at (T_a, 0) and passes through point A at (T_op, P_op). The curve P starts at a higher power value at T_a and intersects the line Q at point B (T_stm, P_stm). The area between the curves is shaded and labeled with circled numbers 1, 2, and 3. Vertical dashed lines mark T_a, T_1, T_op, T_2, T_stm, and T_3. A small label 'K.128(18)_F18' is at the bottom right.](99938fa8d7d80af041634eba601e418b_img.jpg) + +Figure 18: A graph showing Generated (P) and dissipated (Q) power versus temperature (T). The y-axis is labeled 'P, Q (W)' and the x-axis is labeled 'T (°C)'. The graph shows two curves: a straight line labeled 'Q' representing dissipated power, and a curve labeled 'P' representing generated power. The line Q starts at (T\_a, 0) and passes through point A at (T\_op, P\_op). The curve P starts at a higher power value at T\_a and intersects the line Q at point B (T\_stm, P\_stm). The area between the curves is shaded and labeled with circled numbers 1, 2, and 3. Vertical dashed lines mark T\_a, T\_1, T\_op, T\_2, T\_stm, and T\_3. A small label 'K.128(18)\_F18' is at the bottom right. + +Figure 18 – Generated (P) and dissipated (Q) power versus temperature (T) + +The power $P=f(T)$ and $Q=f(T)$ can be expressed in the equations below + +$$P = U_{ap} \cdot I(T) \quad (20)$$ + +where: + +$I(T)$ = current as a function of temperature + +$$Q = \lambda \cdot S \cdot (T - T_a) \quad (21)$$ + +where: + +$\lambda$ = component thermal conductivity + +$S$ = component surface area + +$T_a$ = ambient temperature + +The curve of equation 20 is approximately exponential due to a decreasing resistance of the MOV body with its temperature rising, meanwhile the applied voltage $U_{ap}$ remains unchanged. The curve of equation 21 is approximately linear because the total surface area $S$ and thermal conductivity $\lambda$ are constant for a given MOV product and its installation. + +Figure 18 shows two stable operating points where curves $P=f(T)$ and $Q=f(T)$ intersect at "A" and "B". The lower intersection point A represents a condition of thermal equilibrium where the generated power is equal to the dissipated power. Under this condition the MOV operates at a temperature of $T_{op}$ . The second intersection point B represents the maximum allowable MOV temperature. If the MOV temperature increases above $T_M$ then a thermally unstable condition exists where the generated MOV heat exceeds the system capability to dissipate the heat energy and thermal runaway will result. The temperature difference $\Delta T = T_M - T_{op}$ represents the maximum temperature rise, caused by surge energy absorption. + +This has been a simplistic treatment of thermal stability and further comments are: + +Without a point of intersection of the $P=f(T)$ and $Q=f(T)$ curves, stable operation of an MOV will be unobtainable. + +For clarity, Figure 18, uses linear scales for power temperature. A more accurate assessment is possible if the scales were logarithmic to cover the possible range of powers and temperatures. + +# 10 Time factors + +## 10.1 Initial response to an impulse + +Response time is a depreciated term for two reasons: + +- 1) There is no MOV standard definition or test for such a parameter. +- 2) It is extensively used as a meaningless marketing tool with such feature headlines as "Response time < 0.5 ns (theoretical)" + +The significant time intervals where various aspects of an MOV need to be considered are: + +- MOV ceramic element $\leq 0.5$ ns +- Leaded MOV components with two 25 mm leads $\leq 25$ ns +- Leadless surface mount type MOVs $\leq 0.5$ ns + +As most common surges have front times of 500 ns or more the effects of the above list are not significant. + +Figure 18 shows a leaded MOV current and voltage as a result of an applied voltage step, where the voltage step, $U_m$ , is greater than the MOV's limiting voltage $U_{VB}$ . From MOV's equivalent circuit of Figure 14 following current and voltage waveshapes can be predicted. During the time that the MOV voltage is below $U_{VB}$ the most significant current flow will be the capacitive current ( $i_C$ ) charging the MOV's capacitance. Only when the voltage reaches a certain threshold, $U_1$ at instant $t_1$ , does the resistive current, $i_R$ start to become significant. After $t_1$ the non-linear resistive current quickly increases for little increase of the voltage because the non-linear MOV resistance is rapidly decreasing. The total current passing the MOV is the sum of $i_C$ and $i_R$ . The delayed occurrence of the resistive current and the lead inductance results in a voltage over-shoot $U_{OS}$ , which is the difference between the peak voltage value, $U_p$ , and the stable MOV limiting voltage $U_{VR}$ of the MOV. + +![Figure 19: MOV current and voltage resulting from a pulse step. The figure consists of three vertically aligned plots sharing a common time axis (t). The top plot shows the applied voltage (U_AP) as a step function, with a peak value U_m and a steady-state value U_VB. The middle plot shows the current (i_V) flowing through the MOV, which is the sum of the capacitive current (i_C) and the resistive current (i_R). The current peaks at t_1 and then decays. The bottom plot shows the voltage (U_V) across the MOV, which rises to a peak value U_P at t_2 and then settles to a steady-state value U_OS. The voltage also shows a transient value U_1 at t_1. The source identifier K.128(18)_F19 is present in the bottom right of the third plot.](48a08e5cabec8b75386679d8a57dec3e_img.jpg) + +Figure 19: MOV current and voltage resulting from a pulse step. The figure consists of three vertically aligned plots sharing a common time axis (t). The top plot shows the applied voltage (U\_AP) as a step function, with a peak value U\_m and a steady-state value U\_VB. The middle plot shows the current (i\_V) flowing through the MOV, which is the sum of the capacitive current (i\_C) and the resistive current (i\_R). The current peaks at t\_1 and then decays. The bottom plot shows the voltage (U\_V) across the MOV, which rises to a peak value U\_P at t\_2 and then settles to a steady-state value U\_OS. The voltage also shows a transient value U\_1 at t\_1. The source identifier K.128(18)\_F19 is present in the bottom right of the third plot. + +Figure 19 – MOV current and voltage resulting from a pulse step + +Generally, a greater current rate of rise, $di/dt$ , will result in a higher peak voltage, $U_P$ . Figure 20 shows the results from a circular ceramic of diameter $\phi$ 20 mm $U_{1mA}= 620$ V MOV having a 100 A current step applied. The step front or rise time, $t_R$ , was varied from 0.4 $\mu\text{s}$ to 80 $\mu\text{s}$ . The results confirm a $di/dt$ sensitivity. At 250 A/ $\mu\text{s}$ ( $t_R=0.4$ $\mu\text{s}$ ) $U_P$ is 12% greater than the 13 A/ $\mu\text{s}$ ( $t_R=8$ $\mu\text{s}$ ) $U_P$ value. At 1.3 A/ $\mu\text{s}$ ( $t_R=80$ $\mu\text{s}$ ) $U_P$ is 9% less than the 13 A/ $\mu\text{s}$ ( $t_R=8$ $\mu\text{s}$ ) $U_P$ value. + +![Figure 20: MOV UP variation with 100 A step rise time. This is a line graph showing the peak voltage (U_P) in Volts on the y-axis (ranging from 500 to 1500) against the step rise time in microseconds on the x-axis (logarithmic scale from 0.1 to 100). The data points show a decreasing trend as the rise time increases. The source identifier K.128(18)_F20 is present in the bottom right of the graph.](853ef5420f0432e626e83987e3f38a0b_img.jpg) + +| Step rise time – $\mu\text{s}$ | $U_P$ (V) | +|--------------------------------|-----------| +| 0.4 | ~1050 | +| 1.0 | ~1000 | +| 8 | ~950 | +| 10 | ~920 | +| 80 | ~850 | + +Figure 20: MOV UP variation with 100 A step rise time. This is a line graph showing the peak voltage (U\_P) in Volts on the y-axis (ranging from 500 to 1500) against the step rise time in microseconds on the x-axis (logarithmic scale from 0.1 to 100). The data points show a decreasing trend as the rise time increases. The source identifier K.128(18)\_F20 is present in the bottom right of the graph. + +Figure 20 – MOV $U_P$ variation with 100 A step rise time + +## 10.2 AC power frequency currents + +Protecting mains powered equipment is a major application for MOVs. Incorrect selection of MOVs for this application can lead to MOV failure and result in safety hazards. Thus, it is important that designers understand how MOVs perform under AC power frequency conditions. + +As indicated in Figure 19, the current flowing through an MOV consists of two components: capacitive current ( $I_C$ ) and resistive current ( $I_{VR}$ ) when a power frequency voltage $U_S$ is applied on it. The amplitude of $I_C$ is roughly proportional to the applied voltage ratio $R_{avr}$ (a ratio of the applied voltage peak to the $U_{1mA}$ of the MOV), while the current peak of $I_{VR}$ is roughly proportional to $(R_{avr})^\alpha$ + +(typical non-linear index $\alpha=25$ to 80). When the waveshape of $I_C$ is a sinewave, while the waveshape of $I_{VR}$ is pulse-like, therefore the shape of total current of MOV varies greatly with the variation of $R_{avr}$ , as shown in Figure 21. + +![Figure 21: Current waveforms for various i_R i_C ratios. The figure consists of four subplots (a, b, c, d) showing voltage (V) and current (I) waveforms. Each subplot has a green sine-like voltage waveform and an orange current waveform. a) i_R << i_C: Current is relatively smooth. b) i_R = i_C: Current shows more pulses. c) i_R > i_C: Current has distinct pulses. d) i_R >> i_C: Current is highly pulsed with sharp peaks.](f1df41f68d1ddd39987bd08da7aeadc6_img.jpg) + +Figure 21: Current waveforms for various i\_R i\_C ratios. The figure consists of four subplots (a, b, c, d) showing voltage (V) and current (I) waveforms. Each subplot has a green sine-like voltage waveform and an orange current waveform. a) i\_R << i\_C: Current is relatively smooth. b) i\_R = i\_C: Current shows more pulses. c) i\_R > i\_C: Current has distinct pulses. d) i\_R >> i\_C: Current is highly pulsed with sharp peaks. + +Figure 21 – Current waveforms for various $i_R$ $i_C$ ratios + +![Figure 22: MOV voltage and current half cycle 50 Hz waveforms. The graph shows two waveforms over time. CH1 (1.00V scale) is the voltage waveform, and CH2 (5.00V scale) is the current waveform. Time markers t_0, t_1, t_u, t_i, and t_2 are indicated on the graph. A legend defines t_u as Voltage peak time, t_i as Voltage peak time, t_1 to t_i as Current front time (4.2 ms), and t_i to t_2 as Current tail (3 ms). A time constant tau is also marked.](051638d871c75230edb3d005fa668810_img.jpg) + +$t_u$ = Voltage peak time + $t_i$ = Voltage peak time + $t_1$ to $t_i$ = Current front time, 4.2 ms + $t_i$ to $t_2$ = Current tail, 3 ms + +K.128(18)\_F22 + +Figure 22: MOV voltage and current half cycle 50 Hz waveforms. The graph shows two waveforms over time. CH1 (1.00V scale) is the voltage waveform, and CH2 (5.00V scale) is the current waveform. Time markers t\_0, t\_1, t\_u, t\_i, and t\_2 are indicated on the graph. A legend defines t\_u as Voltage peak time, t\_i as Voltage peak time, t\_1 to t\_i as Current front time (4.2 ms), and t\_i to t\_2 as Current tail (3 ms). A time constant tau is also marked. + +Figure 22 – MOV voltage and current half cycle 50 Hz waveforms + +![Figure 23: Oscilloscope screen showing two waveforms. Channel 1 (CH1) displays the current waveform, which is a series of sharp, irregular pulses. Channel 2 (CH2) displays the voltage waveform, which is a smooth sinusoidal wave. The current peaks in the first few cycles are significantly higher than the subsequent cycles, indicating a transient period. A text annotation on the right side of the screen states 'Current peaks stabilise after about 4 cycles'. The bottom of the screen shows settings: CH1 200mV, CH2 500V, M 10.0ms, and CH1 I 3. A label 'K.128(18)_F23' is also visible.](183007754364096b2d89f42200cf870f_img.jpg) + +Figure 23: Oscilloscope screen showing two waveforms. Channel 1 (CH1) displays the current waveform, which is a series of sharp, irregular pulses. Channel 2 (CH2) displays the voltage waveform, which is a smooth sinusoidal wave. The current peaks in the first few cycles are significantly higher than the subsequent cycles, indicating a transient period. A text annotation on the right side of the screen states 'Current peaks stabilise after about 4 cycles'. The bottom of the screen shows settings: CH1 200mV, CH2 500V, M 10.0ms, and CH1 I 3. A label 'K.128(18)\_F23' is also visible. + +**Figure 23 – First few cycles after AC voltage applied** + +Clause 6.4 and Figure 22 illustrate peak displacement of the voltage and current waveforms. In Figure 22 the current peak point at $t_i$ occurred after the voltage peak point $t_u$ by about 1.8 ms + +Despite having a sinusoidal voltage being applied to the MOV, the current through the MOV is nothing like a sinewave, as shown in Figure 22, where the front duration of the current is longer than its tail duration. + +As indicated in Figure 23, there is an initial transient period of current peaks after application of the sinewave voltage to an MOV, the first current pulse having the highest peak value, after which the peak values decrease and approach a stable state after about 3 to 4 cycles. + +It can also occur where there is some difference between positive and negative current peaks which is called "polarization". + +Hence, for AC peak or watts loss measurement, it is reasonable to take an average value of the plus and the minus peaks of the same cycle at four cycles after the voltage is applied. + +The power loss ( $P$ ) of a linear component is the product of the voltage ( $U$ ) on it multiplied by the current ( $I$ ) through it ( $P=U\times I$ ). This simple formula cannot be used with a non-linear component such as an MOV unless the voltage and current are DC values. + +Calculation of AC power loss is complex because, at higher current levels, the current waveform is asymmetrical triangular like pulse with a reasonably constant limiting voltage during conduction time, see Figure 22. Fortunately, with modern digital oscilloscopes it is easy to multiply and average the recorded waveforms of voltage and current to give the AC power loss. A very approximate estimate of the power loss at higher currents can be made from the formula $P=0.35\times I_p\times U_p$ . + +# 11 Degradation and failure modes + +## 11.1 Stresses that may cause degradation + +Degradation is an undesired departure in the operational performance from the expected performance. The term "degradation" can apply to temporary or permanent failure. The major stresses that may produce MOV degradation and/or failure include following items: + +- Combined stresses of continuous operation voltage and temperature ( $U/T$ stresses) +- Impulse current stress (factors are peak value, duration, repetition times, interval between impulses, and polarity) +- Climatic conditions + +The characteristics that may be used to evaluate degradation are + +- Varistor voltage ( $U_{1\text{mA}}$ ) + +- Limiting voltage +- Resistive current or watt loss +- Nonlinearity index ( $\alpha$ value) + +The most common characteristic used is a percentage change of $U_{1\text{mA}}$ . + +## 11.2 Impulse current degradation + +The results shown in this clause are for a single polarity impulse life test where the end of life criteria was a 10% fall in $U_{1\text{mA}}$ . Figure 24 and Figure 25 show how the degradation affected the low and high current indexes. The "Before" curve is prior to the start of life test and the "After" curve is measured following the life test. + +The curves in Figure 24 show that the DC small current region the index $\alpha_{21}$ drops dramatically in both directions after the life test, with a larger reduction in opposite polarity to the impulse current. + +The curves in Figure 25 demonstrated that the impulse life test had little effect on impulse V-I characteristic. + +![Figure 24: A graph showing the change in the nonlinearity index alpha_21 (Y-axis, 0 to 80) versus the logarithm of current LogI (X-axis, 10^1 to 10^4). The graph displays three curves: 'Before' (black line), 'After' (blue line, labeled B+), and 'After' (red line, labeled B-). The 'Before' curve shows a significant increase in alpha_21 with LogI. The 'After' curves show a dramatic drop in alpha_21, with the red curve (B-) remaining relatively flat around 23, and the blue curve (B+) slightly increasing from 26 to 30.](ed4ead5d57191d85eee9880ec32c4628_img.jpg) + +| LogI | alpha_21 (Before) | alpha_21 (After B+) | alpha_21 (After B-) | +|--------------------------|-------------------|---------------------|---------------------| +| 10^1 | 43 | 26 | 23 | +| 10^2 | 50 | 27 | 23 | +| 10^3 | 61 | 28 | 23 | +| 2.35 mA (approx 10^3.37) | 70 | 29 | 23 | + +K.128(18)\_F24 + +Figure 24: A graph showing the change in the nonlinearity index alpha\_21 (Y-axis, 0 to 80) versus the logarithm of current LogI (X-axis, 10^1 to 10^4). The graph displays three curves: 'Before' (black line), 'After' (blue line, labeled B+), and 'After' (red line, labeled B-). The 'Before' curve shows a significant increase in alpha\_21 with LogI. The 'After' curves show a dramatic drop in alpha\_21, with the red curve (B-) remaining relatively flat around 23, and the blue curve (B+) slightly increasing from 26 to 30. + +Figure 24 – Low current (30 $\mu\text{A}$ to 2.35 mA) $\alpha_{21}$ change pre- and post-impulse current life test + +![Figure 25: A log-log plot showing the change in the alpha_21 parameter over time (Log t) for an MOV. The y-axis is alpha_21, ranging from 0 to 80. The x-axis is Log t, ranging from 10^2 to 10^5. Two curves are shown: 'Before' (red line) and 'After' (black line). Both curves show a sharp decrease in alpha_21 as Log t increases, with the 'After' curve showing a more significant degradation.](152efae989544ee653283e8de26cc9b1_img.jpg) + +| Log t | alpha_21 (Before) | alpha_21 (After) | +|-------|-------------------|------------------| +| 10^2 | ~65 | ~65 | +| 10^3 | ~15 | ~10 | +| 10^4 | ~8 | ~5 | +| 10^5 | ~4 | ~2 | + +Figure 25: A log-log plot showing the change in the alpha\_21 parameter over time (Log t) for an MOV. The y-axis is alpha\_21, ranging from 0 to 80. The x-axis is Log t, ranging from 10^2 to 10^5. Two curves are shown: 'Before' (red line) and 'After' (black line). Both curves show a sharp decrease in alpha\_21 as Log t increases, with the 'After' curve showing a more significant degradation. + +**Figure 25 – Low current (200 A to 40 kA) $\alpha_{21}$ change pre- and post-impulse current life test** + +## 11.3 Failure criteria + +Two types of failure criteria are presently adopted for reliability evaluation of an MOV: "parameter degradation criteria" and "physical destruction criteria" + +Parameter assessment for degradation criteria can be in the following areas: + +- 1) Varistor voltage $U_{1mA}$ has decreased by more than 10% of the initial value. +- 2) Residual/limiting voltage $U_{res}$ at a specified impulse current has increased by more than 10% of the initial value. +- 3) Leakage current or watt-loss shows a steady increase. + +Residual voltage always changes upwards when an MOV being subjected to repetitive impulse stresses, despite the varistor voltage ( $U_{1mA}$ ) going down. The increase of the residual voltage is ordinarily about +3% when the $U_{1mA}$ has dropped by -10%. Therefore, a "+10% increase of the limiting voltage" is never observed. + +There are various potential MOV physical failure modes, which are determined by correlation between stresses and MOV design, as well as processing. Figure 26 shows some typical physical destructions with labels linked to the reasons below: + +- 1) Thermal puncture (breakdown) hole in the ceramic bulk. +- 2) Etched silver layer. + +A part of the silver layer adjacent to the metal lead (plate) has been melted by repeated or high-level impulse current, or by flashover. This type of destruction is difficult to detect via an ordinary electrical test, making it necessary to remove the coating for a visual inspection. + +- 3) Cracking of insulation coating or separation. + +Rapid temperature change or repeated impulse stresses are more likely to produce cracking of the insulation coating. + +- 4) Cracking of the ceramic bulk. +- 5) A layer of ceramic bulk parted from the bulk. + +![Figure 26: Various MOV physical destructions. The image shows five different types of physical damage to MOV components, each labeled with a red box and number: 1. A circular MOV with a dark, cratered center; 2. A square MOV with a cracked and delaminated top surface; 3. A square MOV with a dark, charred top surface; 4. A square MOV with a cracked and flaking top surface; 5. A square MOV with a dark, charred top surface. A separate image on the right shows a cross-section of a MOV with a white outline indicating a crack or delamination path, labeled with a red box and number 2.](19fd552435a80d0ffda518b710d16908_img.jpg) + +Figure 26: Various MOV physical destructions. The image shows five different types of physical damage to MOV components, each labeled with a red box and number: 1. A circular MOV with a dark, cratered center; 2. A square MOV with a cracked and delaminated top surface; 3. A square MOV with a dark, charred top surface; 4. A square MOV with a cracked and flaking top surface; 5. A square MOV with a dark, charred top surface. A separate image on the right shows a cross-section of a MOV with a white outline indicating a crack or delamination path, labeled with a red box and number 2. + +**Figure 26 – Various MOV physical destructions** + +## 11.4 Additional MOV behaviours and effects + +The major MOV behaviours and effects have been covered earlier. This clause covers second-order behaviours and effects, which may be met in MOV testing. + +For example, the application and removal of a voltage to an MOV produces transient discharge currents that persist on a time scale extending from 10 ns to about 30 h. This behaviour cannot be explained by the DSB model. + +It has been proved that there is polarization and de-polarization current in the MOV ceramics. The word "polarization" refers to a process of producing a relative displacement of positive and negative bound charges in the grain boundary phase (see clause 6.3) by applying an electric field. Parallel leakage paths are created with Schottky barrier-controlled current flow. + +Another behaviour that is caused by variation of trap density at the grain boundary depletion layer, which affects the time-dependent stability of an MOV. + +# 12 Operation states and related performances + +In this clause, an MOV's typical operational states and related characteristics and ratings are discussed. The discussion includes parameter definitions and test methods, as well as application considerations. + +## 12.1 Typical operation states and basic requirements + +The MOV is a surge protection component, which functions by limiting impulse overvoltage and diverting the impulse current. + +In an application, the MOV operation state can be in three modes: standby, voltage limiting and TOV-endurance. + +In its entire service life, an MOV should meet some basic requirements that are requested by the operation states. These requirements are represented by related characteristics, ratings and parameters, as listed in Table 1. + +**Table 1 – Typical operational states and performances** + +| Standby operation state | Surge suppression state | TOV endurance state | +|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------| +| Electrical stresses imposed on MOV | | | +| Maximum continuous operating voltage (MCOV) | MCOV or Specified impulse current | TOV | +| Ratings and parameters | | | +| varistor voltage $U_n$
$U_n$ -tolerance $\delta U_n$
voltage gradient V/mm
MCOV
standby watt loss $P_0$ and its stability, or
resistive leakage current $I_{LR}$ and its stability
capacitance $C_V$
Temperature dependence of V-I characteristics
Endurance test under $U/T$ stresses (1000hrs) | Impulse limiting performance
limiting voltage $U_{Lim}$
nominal discharge current $I_n$
capability of impulse current diversion
response time $t_{res}$
voltage overshoot $\Delta u_{OV}$
impulse handling capability
Max. discharge current of short / long impulse $I_{MS}$ , / $I_{ML}$
Repeated discharge current of short / long impulse $I_{MS}$ , / $I_{ML}$
Average impulse power $P_{av}$
Maximum impulse energy $E_{max}$ | MOV component
TOV endurance voltage $U_{TOV}$ or
TOV withstanding energy $E_{TOV}$ | +| Characteristic formulas and curves | | | +| V-I characteristic formula or curves for AC or DC | V-I characteristic formula or curves of impulse life | V-I characteristic formula or curves of current peak vs voltage peak | + +## 12.2 Operational performances related to standby operation state + +### 12.2.1 Varistor voltage $U_n$ ( $U_{1mA}$ ), tolerance $\delta U_n$ , voltage gradient V/mm + +Varistor voltage $U_n$ , also named DC reference voltage, is used to signify the transition point between the insulation state and conduction state of an MOV. According to the product specification, $U_n$ is measured at DC 1 mA $\pm 10\%$ , after a conduction period of 20 ms to 50 ms, independent of MOV size. + +**Varistor voltage $U_n$** is usually used as a reference voltage, for example: + +- Applied voltage ratio (AVR)= $U_{ap} / U_n$ , where $U_{ap}$ refers to the peak of AC voltage or DC voltage to be applied on the MOV. The AVR is used to express the severity of applied voltage upon an MOV. +- Limiting voltage ratio (LVR)= $U_{mp} / U_n$ , where $U_{mp}$ refers to the peak of the limiting voltage on the MOV. at a specified impulse current passing through it. The LVR is used to express the capability of suppressing surge voltage of the MOV +- Change rate of varistor voltage $\Delta U_n=(U_{n1}-U_{n0})/U_{n0}$ , where $U_{n0}$ and $U_{n1}$ refer respectively to the measured varistor voltage before and after test, for the most test items of MOV, $\Delta U_n$ is used as a pass (failure) criteria. In the case of regular checks on field MOVs, $\Delta U_n$ (with respect to the initial value of $U_n$ ) is often used as a criterion of degradation, if the $\Delta U_n$ is beyond a specified value, the MOV should be replaced. + +Lack of size sensitivity means that $U_n$ is measured at different current density for different sizes. However, some important properties of MOV, such as temperature coefficient of voltage and current and the degree of degradation, are much sensitive to the current density, in this respect, the varistor voltage $U_n$ may be defined as such a voltage that is measured at a specified current density, for example 0.1 mA/cm2. + +**Tolerance of varistor voltage ( $\delta U_n$ )** is an important parameter for MOV selection, the top value of the $\delta U_n$ is usually limited by the maximum limiting voltage, while its low-end value is limited by the permitted degradation during the service life when taking the variation of system voltage into account. + +**Voltage gradient (V/mm)** refers to varistor voltage per unit thickness. This parameter has three effects on MOV selection: generally, higher gradient means lower energy handling capability, lower cost, and better voltage limiting property (lower limiting voltage ratio). + +The voltage gradient of most commercial MOVs ranges from about 100 V/mm to 220 V/mm for medium and high varistor voltage units. + +### 12.2.2 Maximum continuance operating voltage $U_M$ + +The rating MCOV signifies such a voltage that may be applied continuously at a specified temperature. + +At the discovery time of ZnO varistor, AC MCOV ( $U_{Mac}$ ) was so defined that the peak of $U_{Mac}$ shall be equal to or less than the lowest $U_n$ of the specified tolerance, which is $0.9U_{n0}$ ( $U_{n0}$ is nominal varistor voltage) in case of $\pm 10\%$ tolerance, + +$$U_{Mac} = \frac{0.9U_{n0}}{\sqrt{2}} \approx 0.64U_{n0} \quad (22)$$ + +As for system voltages other than AC source, including DC source, the MCOV shall be such a voltage value under which the MOVs generate about the same watt loss as that at $U_{Mac}$ , based on this rule, the equation 23 was derived by experiments + +$$U_{Md.c} \approx 1.3U_{Mac} \quad (23)$$ + +From above discussion, the users should be aware that a particular magnitude of $U_{Mac}$ and $U_{Md.c}$ are affected by $U_n$ -tolerance. + +MCOV is not measurable, its conformity is evaluated by the following tests: + +- Reliability screen test in the course of processing. +- Endurance test under MCOV and specified temperature. +- Operation duty test: MOV shall be thermally stable under MCOV which is applied on the samples immediately after specified impulse test. +- Life test. + +### 12.2.3 Standby watt loss $P_0$ , resistive leakage current $I_{LR}$ , total leakage current (rms) $I_L$ + +These three parameters are related with MCOV. Generally, measurement of $P_0$ or $I_{LR}$ is sufficient, $P_0$ being most easy to measure. The total leakage current (rms) $I_L$ should be controlled for those MOVs that are intended to be connected to protective earth in the application. + +### 12.2.4 Capacitance $C_V$ + +The MOV capacitance, $C_V$ , has the following dependences: + +- The value of $C_V$ is about inversely proportional to varistor voltage rather than to bulk thickness. +- The value of $C_V$ may be critical to the application. To understand the need requires analysis of circuit in which the MOV to be used in. +- The MOV $C_V$ value has some "memory effect", where any previous MOV electrical stress will affect a subsequent measured $C_V$ value. Normally, there can be a reduction in the measured capacitance value by 10% or more, therefore $C_V$ measurement should be the first test of a series tests. + +### 12.2.5 Temperature dependence of the V-I characteristics + +Knowing the temperature dependence of an MOV V-I formula is of great benefit to users and producers, who can then predict the voltage/current values at any temperature ranging e.g., from 20 °C to 160 °C, if the room temperature of $U_n$ is known, see the example below. + +This example uses an MOV of $\phi$ 20 mm, $U_{n0}=620$ V, $U_{n0}=627.8$ V, having a DC V-I formula given in equations 24 to 27, which are expressed as a normalized voltage ratio $[VR]_{nom}$ in a current range of 1 $\mu$ A to 10 mA in a temperature range of 20 °C to 160 °C. + +$$[VR]_{nom} = \frac{V_{T,I}}{V_n} = A_0 \times I^{(A_1+A_2 \times \log I)} \quad (24)$$ + +$$A_0 = 0.9 - 0.0013 \times T - 1.83 \times 10^{-5} \times T^2 \quad (25)$$ + +$$A_1 = 0.039 - 7.85 \times 10^{-4} \times T + 1.73 \times 10^{-5} \times T^2 \quad (26)$$ + +$$A_2 = -0.037 + 8.57 \times 10^{-5} \times T - 2.36 \times 10^{-6} \times T^2 \quad (27)$$ + +Where: $V_{T,I}$ is the voltage of the unit at ambient temperature $T$ (°C) and current $I$ ( $\mu$ A). $V_n$ is the varistor voltage of the unit at room temperature. + +#### Question + +What is the voltage of an above type of unit that has been heated to 115 °C, when an MOV current of 100 $\mu$ A flows, if its $U_n$ at room temperature is 627.8 V? + +#### Solution + +Putting $T=115$ °C into equations 25, 26 and 27, give $A_0=0.508$ , $A_1=0.178$ , $A_2=-0.025$ + +Putting ( $A_0=0.508$ , $A_1=0.178$ , $A_2=-0.025$ , $I=100$ $\mu$ A) into equation 24 give $[VR]_{nom}=0.889$ + +The answer voltage is $0.889 \times 627.8 = 558.1$ V. + +## 12.3 Operational performances related to surge suppression state + +When an MOV provides surge protection it has to meet two requirements; sufficient surge impulse current capability and an acceptable peak voltage limiting. + +### 12.3.1 Protection capability + +The MOV should voltage limit the expected surges down to a level that is within the protected object (PO) capability. Besides the obvious surge voltage capability of the PO in some cases the resulting surge current taken by the PO needs to be considered. In most cases the input impedance of the PO in parallel with the MOV is much higher than the equivalent resistance of the MOV during surges only; therefore, the peak voltage needs to be considered. When the input impedance of the PO is low, such as with a rectifier system, then the surge current taken by the PO needs to be considered. + +The "Maximum limiting voltage" at specified surge current is the usual parameter for evaluating voltage limiting capability of an MOV. The interaction between the MOV and PO in terms of surge current division is not commonly done because the PO surge impedance is often not known. + +### 12.3.2 Impulse withstand capability + +In functioning as a surge protective component, the MOV has to withstand the specified current surges. Surge durations vary from short (high current) ones to long (low-current) ones. Generally, an 8/20 current is regarded as short impulse, while 10/1000 or 10/350 or 2 ms rectangular currents are regarded as wide impulses. Different impulse durations and applications have different effects on MOVs, making it necessary to have ratings for "maximum single impulse current" and "repetitive + +impulse current" specified separately for short impulse (denoted "S") and for wide impulse (denoted "L"). + +The ratings classifying impulse withstanding capability include: + +- 1) Maximum impulse current (one time)— $I_{MS}$ , $I_{ML}$ . +- 2) Repeated impulse current (10 or 15 times) $I_{RS}$ , $I_{RL}$ . +- 3) Rated impulse power $P_0$ (test current-wide impulse). +- 4) Maximum impulse energy $E_M$ (test current-wide impulse). + +The four test items mentioned above are covered by acceptance testing and delivery testing that is performed on a few selected samples. During the manufacturing processing, all semi-finished units should have to pass impulse aging and screening tests. The main aim of impulse aging and screening testing is to discover and reject those units that may be premature failures, and to further improve the impulse endurance of good quality units. + +## 12.4 Operational performance related to TOV endurance state + +MOVs that are intended for power circuits uses should have ratings and characteristics related to the TOV condition. Unfortunately, at present there is no consensus on what those component parameters are. For AC power systems, [b-IEC 60364-4-44] provides generic safety requirements for electrical installations in the event of voltage disturbances and electromagnetic disturbances. Here are two component proposals coming from manufacturing companies. + +- TOV endurance voltage, $U_{TOV}$ + +The specified maximum power frequency voltage, $U_{TOV}$ , is applied to the MOV for 5 s +0.5 s, -0 s followed by the 15-min application of the MOV MCOV, which shall show a decreasing temperature as it recovers from the $U_{TOV}$ stress. The transition from $U_{TOV}$ to MCOV shall be less than 100 ms. + +This rating is intended for co-ordination with AC power system values. + +- TOV withstanding energy, $E_{TOV}$ + +This rating is the average energy, $E_{TOV}$ , deposited into an MOV prior to it going into thermally runaway when a specified AC power frequency source is applied. The AC source has a voltage that is able to producing an initial current of about 0.2 A/cm2 into the MOV together with a prospective short-circuit current of $\geq 10$ A. The energy value shall be measured with an accuracy of $\pm 3\%$ . The test is performed on three samples, the average energy of the three shall be not less than the specified $E_{TOV}$ value. + +## 12.5 Impulse life + +### 12.5.1 Impulse life curves and impulse life equations + +The impulse life curves of MOV, also termed impulse peak current de-rating curves, expressed the quantitative relationship between three variables of maximum impulse current peak ( $I_p$ ), equivalent rectangular pulse width ( $\tau$ ), and impulse life numbers ( $n$ ). Generally, the $\tau$ ranges from 20 $\mu\text{s}$ to 10 ms, the $n$ ranges from 1 time to $10^6$ times + +It has been demonstrated that the accumulated failure rate of MOV's impulse life tests is in accordance with the Weibull distribution function, from which three variables of characteristic life can be obtained which are termed respectively: + +- 1) Median life $n_{med}$ , at which half of the units concerned failed. +- 2) Average life $n_{av}$ , an average value of the life times among all units concerned. +- 3) Guaranteed life $n_{gua}$ , or minimum life times among all units concerned + +Therefore, there are three types of impulse life characteristic, which may be expressed as curves or as equations. + +Figure 27 and Figure 28 show example of impulse life curves which are identical, but expressed with different coordinates. Figure 27 shows against time $\log I_p = f(\log \tau)_{n=C}$ is straight lines of good linearity, but Figure 28 shows against repetitions ( $n$ ) the linearity of the line $\log I_p = f(\log n)_{\tau=C}$ is poor when $n$ is less than 100. + +![Figure 27: Impulse life curves expressed as log Ip = f(log tau), n=constant. The graph is a log-log plot with lg Ip on the y-axis (ranging from 10^0 to 10^5) and Log tau (μs) on the x-axis (ranging from 10^-2 to 10^4). Multiple straight lines with negative slopes are shown, each corresponding to a constant value of n (1, 10^1, 10^2, 10^3, 10^4, 10^5, 10^6). Specific time markers 17.5 μs, 500 μs, and 6.37 ms are indicated on the x-axis. The label K.128(18)_F27 is at the bottom right.](1c2028183a35357e7238438a4af9cab7_img.jpg) + +Figure 27: Impulse life curves expressed as log Ip = f(log tau), n=constant. The graph is a log-log plot with lg Ip on the y-axis (ranging from 10^0 to 10^5) and Log tau (μs) on the x-axis (ranging from 10^-2 to 10^4). Multiple straight lines with negative slopes are shown, each corresponding to a constant value of n (1, 10^1, 10^2, 10^3, 10^4, 10^5, 10^6). Specific time markers 17.5 μs, 500 μs, and 6.37 ms are indicated on the x-axis. The label K.128(18)\_F27 is at the bottom right. + +Figure 27 – Impulse life curves expressed as $\log I_p = f(\log \tau)$ , $n=\text{constant}$ + +![Figure 28: Impulse life curves expressed as log Ip = f(log n), tau=constant. The graph is a log-log plot with lg Ip on the y-axis (ranging from 10^0 to 10^5) and n on the x-axis (ranging from 10^0 to 10^7). Multiple curves are shown, each corresponding to a constant value of tau (20 μs, 50 μs, 100 μs, 200 μs, 500 μs, 1 ms, 2 ms). The curves are straight at high n but bend at low n (below 100). The label K.128(18)_F28 is at the bottom right.](8d5d12ba8fe7313bc891241275c64d20_img.jpg) + +Figure 28: Impulse life curves expressed as log Ip = f(log n), tau=constant. The graph is a log-log plot with lg Ip on the y-axis (ranging from 10^0 to 10^5) and n on the x-axis (ranging from 10^0 to 10^7). Multiple curves are shown, each corresponding to a constant value of tau (20 μs, 50 μs, 100 μs, 200 μs, 500 μs, 1 ms, 2 ms). The curves are straight at high n but bend at low n (below 100). The label K.128(18)\_F28 is at the bottom right. + +Figure 28 – Impulse life curves expressed as $\log I_p = f(\log n)$ , $\tau=\text{constant}$ + +The curves in Figure 27 can be expressed as equation 28, + +$$\log I_p = B_n - b_n \log \tau = B_n - \log \tau^{b_n}, n = \text{constant} \quad (28)$$ + +The curves in Figure 28 can be expressed as equation 29 + +$$\log I_p = A_\tau - a_\tau \log n = A_\tau - \log n^{a_\tau}, \tau = \text{constant} \quad (29)$$ + +It is clear that all impulse life characteristics of an MOV can be expressed by the two equations of 28 and 29, or in other words, by the four variables of $A_\tau$ , $a_\tau$ , $B_n$ , $b_n$ . The aim of the impulse life test is to establish life data, and from the results the four variables can be obtained via calculations + +### 12.5.2 Procedure for determination of MOV's impulse life characteristics + +The key steps of this procedure are listed below: + +The impulse life test plan should cover + +- 1) Three impulse waveforms for the life test +which are $\tau_S = 20 \mu\text{s}$ , $\tau_M = 200 \mu\text{s}$ , $\tau_L = 2000 \mu\text{s}$ . +- 2) Two peak current for each waveform used +The high-level current peak $I_H$ corresponds roughly to $n=100$ at interval $\Delta t = 60 \text{ s}$ , The low-level current peak $I_L$ corresponds roughly to $n=10,000$ at interval $\Delta t = 20 \text{ s}$ , + +This means 6 sample groups shall be tested under the stress conditions of $[\tau_S, I_H]$ , $[\tau_S, I_L]$ , $[\tau_M, I_H]$ , $[\tau_M, I_L]$ , $[\tau_L, I_H]$ , $[\tau_L, I_L]$ , with each group consisting of 20 samples. + +- 3) All samples shall be of the same design (including nominal varistor voltage, voltage gradient, and sizes), using the same materials and the same manufacturing processes. + +Perform impulse tests to failure and analyse the results + +- 1) Failure criteria +varistor voltage in any direction has dropped by more than 10%, and/or +breakdown or flashover happened during impulse applications. +- 2) Testing of each group is completed when all group samples have failed. +- 3) Fit the test result data of each sample group to the Weibull distribution function to find the three life times $n_{med}$ , $n_{med}$ , $n_{gua}$ +- 4) Calculate the six $n$ values obtained from six groups of sample for four variables of $A_\tau$ , $a_\tau$ , $B_n$ , $b_n$ , herein $n$ refers to any one of the $[n_{med}$ , $n_{med}$ , $n_{gua}]$ + +# 13 Application examples + +## 13.1 Introduction + +MOVs are used in a vast number of electric and electronic applications. This clause covers a few of the most common applications which are: + +- Operation principles of overvoltage suppression and surge current diversion. +- Classification in terms of application and basic requirements for protective systems. +- Circuit connection mode. +- Field check and replacement. + +## 13.2 Operation principles of a basic overvoltage protective system + +### 13.2.1 Basic overvoltage protective system + +The basic overvoltage protective system with power distribution can be considered as consisting of four elements: system voltage source, impulse overvoltage source, protective component(s) (MOV) and the PO. To achieve PO protection, the MOV used must satisfy the PO and system needs. + +### 13.2.2 The principle of voltage suppression + +In an overvoltage protective system, the MOV is always connected in parallel with the POs. According to Thevenin's theorem, the system source and impulse source are represented by a series combination of an equivalent electromotive force (emf) and source impedance ( $Z_s$ ), making $\text{emf} = U_0 + U_{ov}$ . In most cases, the input impedance of the PO is much higher than the effective + +resistance of the MOV during the impulse, hence little impulse current enters the PO. Under such circumstances, the voltage on the MOV ( $U_V$ ) and the impulse current peak passing the MOV can be found by use of a graphic method or by solving the two equations below: + +$$U_V = U_{V0} \times I_V^B \quad (\text{MOV's impulse V-I formula})$$ + +$$U_V = U_S - I_V \cdot Z_S \quad (\text{Load line of source resistance})$$ + +### 13.2.3 The principle of surge current diversion + +When the input impedance of the protected object, PO, is comparable with the MOV's resistance during the impulse, there must be some impulse current entering the PO. The three current components of $I_S$ , $I_{VR}$ and $I_{PO}$ can be easily measured for example in case of Figure 29, which is a standard AC to DC power circuit. + +In order to suppress incoming impulse overvoltages that may occur at AC input port, an MOV (VR) of $\Phi=14$ mm, $U_{n0}=430$ V is installed. In this case, the measured input resistance of the PO was 1.76 $\Omega$ . If the 8/20 current is applied to the AC input port, then the current share between VR ( $I_{VR}$ ) and the PO ( $I_{PO}$ ) can be calculated after the resistance formula of the VR has been established. + +VR resistance formula + +$$R_{VR} = 10^y$$ + +where: + +$$y = 2.96 - 1.18 \times \log I + 0.0565 \times (\log I)^2$$ + +Input resistance $R_{in} = R_{PO} = 1.76 \Omega$ + +For the outcome of the calculation, see Table 2. + +![Circuit diagram of impulse overvoltage protection using MOV VR. It shows an AC input with a fuse (Fu) and a varistor (VR) in parallel. The VR is labeled with resistance Rin and voltage U. The circuit then branches into a bridge rectifier (D1, D2, D3, D4) and a load consisting of a resistor (R) and a capacitor (C) in parallel. The output is labeled K.128(18)_F29.](ceb967656aa87e9c8a39e8fe063f8f4c_img.jpg) + +Circuit diagram of impulse overvoltage protection using MOV VR. It shows an AC input with a fuse (Fu) and a varistor (VR) in parallel. The VR is labeled with resistance Rin and voltage U. The circuit then branches into a bridge rectifier (D1, D2, D3, D4) and a load consisting of a resistor (R) and a capacitor (C) in parallel. The output is labeled K.128(18)\_F29. + +Figure 29 – Impulse overvoltage protection using MOV VR + +Table 2 – Current sharing between VR and PO + +| | | | | | | | | | +|-------------------------|-------|-------|-------|-------|-------|-------|-------|-------| +| Current, $I_{VR}$ (A) | 20 | 50 | 100 | 200 | 500 | 1000 | 2000 | 3000 | +| Voltage $V_R$ (V) | 662.9 | 656.5 | 669.9 | 699.8 | 768.7 | 848.2 | 958.2 | 1014 | +| $I_{PO} = V_R / 1.76$ | 376.6 | 373 | 380.6 | 397.6 | 436.8 | 481.9 | 544.5 | 591.1 | +| $I_S = I_{VR} + I_{PO}$ | 396.6 | 423.0 | 480.6 | 597.6 | 936.8 | 1482 | 2544 | 3591 | +| Ratio $I_{VR}/I_S$ | 0.05 | 0.12 | 0.21 | 0.33 | 0.53 | 0.67 | 0.79 | 0.84 | +| Ratio $I_{PO}/I_S$ | 0.95 | 0.88 | 0.79 | 0.67 | 0.47 | 0.33 | 0.21 | 0.16 | + +It is clear that at the low end of the incoming impulse current, that most of it enters into the PO, which may cause electromagnetic compatibility (EMC) problems or harm other components which is not desirable. + +## 13.3 Classification of applications of MOV's and standards requirements + +At present, there is no definite classification for MOVs; according to their main usages, MOVs may be roughly used for: + +- Electric power system protection against both lightning and switching surges. This application area is vast and varied. +- Signal and data networks. +- Electrostatic discharge suppression, especially the surface mount type SMV MOV. +- Absorbing magnetic field energy when motors or generators are turned off. +- Noise suppression of micro-motors (ring-shape varistor). +- Transient equi-potential bonding of normally unearthed conductors. +- Other special utilization + +In term of protective effects, the overvoltage protective systems using MOVs play an important role of ensuring protected object(s) meet three types of standard requirements: + +- 1) Insulation coordination requirements (e.g., [b-IEC 60664]) +- 2) Surge immunity requirements (e.g., [b-IEC 61000-4-5] and [ITU-T K.77]) +- 3) Safety requirements (e.g., [b-IEC 62368-1]) + +## 13.4 Connection modes of MOV in application circuits + +### 13.4.1 Protective circuits for two-wire system + +![Figure 30: Six circuit diagrams (a-f) showing different protective circuit configurations for a two-wire system (H=live, L=neutral, PE=protective earth) connected to protected terminal equipment (PTE). Each diagram shows the connection of MOVs (U) and other components like a diode or a varistor to protect the PTE from overvoltages.](ff5f89b660edddb67971d7d3d4ce87ef_img.jpg) + +The figure displays six circuit diagrams labeled a) through f), each showing a different protective circuit configuration for a two-wire system. The system consists of a live conductor (H), a neutral conductor (L), and a protective earth conductor (PE). The protected terminal equipment (PTE) is connected to these conductors. MOVs (U) are used to limit overvoltages. In diagram a), an MOV is connected between H and PE. In diagram b), an MOV is connected between L and PE. In diagram c), two MOVs are connected between H and PE and L and PE. In diagram d), an MOV is connected between H and PE, and a diode is connected between L and PE. In diagram e), an MOV is connected between H and PE, and two MOVs are connected between L and PE. In diagram f), an MOV is connected between H and PE, and two MOVs are connected between L and PE, with a diode connected between L and PE. The diagrams are labeled K.128(18)\_F30. + +Figure 30: Six circuit diagrams (a-f) showing different protective circuit configurations for a two-wire system (H=live, L=neutral, PE=protective earth) connected to protected terminal equipment (PTE). Each diagram shows the connection of MOVs (U) and other components like a diode or a varistor to protect the PTE from overvoltages. + +**Figure 30 – Two-wire powering system protective circuits (H=live, L=neutral, PE=protective earth, PTE=protected terminal equipment)** + +### 13.4.2 Special functions of MOV in electric and electronic circuits + +Besides limiting transient overvoltages, an MOV can also be used as a special circuit component, three instances are given below: + +- 1) MOV functions as a voltage stabilizer in high voltage and small current DC circuits. +- 2) MOV functions as a voltage sensing component. + +In Figure 31 the MOV VR functions as a voltage sensing component in an AC constant current circuit that drives a constant current into the load via an L-C-L network. The VR is in OFF state in normal + +operation, in case of open-circuited of the load, the voltage $U_{out}$ goes up greatly and the VR turns conduction that drives a control circuit to turn off the switch S1. + +![Figure 31: Circuit diagram showing a varistor VR acting as a voltage sensing component. An AC source Us is connected to a switch S1, which is in series with an inductor L. A capacitor C is connected in parallel across the inductor. A varistor VR and a resistor R1 are connected in series across the inductor. The output voltage Uout is taken across the inductor and is connected to a transformer and a load. A control circuit (cont.) and a measurement circuit (Mes.) are connected to the varistor VR. A symbol for an S-Coil is shown at the bottom left. The diagram is labeled K.128(18)_F31.](6cc85a2b62fd8a2a3faab29730f20e81_img.jpg) + +Figure 31: Circuit diagram showing a varistor VR acting as a voltage sensing component. An AC source Us is connected to a switch S1, which is in series with an inductor L. A capacitor C is connected in parallel across the inductor. A varistor VR and a resistor R1 are connected in series across the inductor. The output voltage Uout is taken across the inductor and is connected to a transformer and a load. A control circuit (cont.) and a measurement circuit (Mes.) are connected to the varistor VR. A symbol for an S-Coil is shown at the bottom left. The diagram is labeled K.128(18)\_F31. + +**Figure 31 – Varistor VR acts as the voltage sensing component to stabilise the voltage** + +- 3) MOV functions as a voltage equalizer, Figure 32 is an example. + +![Figure 32: Circuit diagram showing three MOVs (VR1, VR2, VR3) connected in parallel with three diodes (D1, D2, D3) in series. The MOVs are connected across the diodes to equalize the reverse diode voltages. The diagram is labeled K.128(18)_F32.](a161a2bbb4d830e847ccb4f44b7e41a9_img.jpg) + +Figure 32: Circuit diagram showing three MOVs (VR1, VR2, VR3) connected in parallel with three diodes (D1, D2, D3) in series. The MOVs are connected across the diodes to equalize the reverse diode voltages. The diagram is labeled K.128(18)\_F32. + +**Figure 32 – MOVs equalising the reverse diode voltages of a series diode chain** + +## 13.5 Quantitative relationship between voltages of the MOV for power circuitry protection + +Figure 33 shows the relationship between the different voltage parameters relevant to MOV power circuit protection. Unless otherwise specified these parameters should meet the criteria given by equations 30 to equation 34. + +![Figure 33: A horizontal timeline diagram showing various voltage parameters. From left to right, the parameters are: UO (Nominal system voltage), UOM (Possible maximum value of the system voltage), UC (Maximum continuous voltage AC), UNL (Low limit of the varistor voltage tolerance), UNH (Top limit of the varistor voltage tolerance), UP (Protection level of the varistor used), and UPTE (Max. allowable surge voltage on the protected equipment). Shaded regions indicate the tolerance range between UNL and UNH, and the protection range between UOM and UP.](48f209b7c0c1f91af40cfc3466dbd534_img.jpg) + +Figure 33: A horizontal timeline diagram showing various voltage parameters. From left to right, the parameters are: UO (Nominal system voltage), UOM (Possible maximum value of the system voltage), UC (Maximum continuous voltage AC), UNL (Low limit of the varistor voltage tolerance), UNH (Top limit of the varistor voltage tolerance), UP (Protection level of the varistor used), and UPTE (Max. allowable surge voltage on the protected equipment). Shaded regions indicate the tolerance range between UNL and UNH, and the protection range between UOM and UP. + +**Figure 33 – MOV voltage parameters relevant to power circuit protection** + +$U_{PTE}$ – Max. allowable surge voltage on the protected equipment + +$U_P$ – Protection level of the varistor used + +$U_{NH}$ – Top limit of the varistor voltage tolerance + +$U_{NL}$ – Low limit of the varistor voltage tolerance + +$U_C$ – Maximum continuous voltage AC + +$U_{OM}$ – Possible maximum value of the system voltage + +$U_O$ – Nominal system voltage + +- 1) The protection level $U_P$ of the MOV and the maximum permitted surge voltage $U_{PTE}$ of the protected terminal equipment (PTE) should be in accordance with equation 30. The factor $(0.8 \sim 0.9)$ aims to counteract the effects of residual voltage increment cause by MOV's degradation and by the voltage on the connecting wires between the MOV and the PTE. + +$$U_P \leq (0.8 \sim 0.9) U_{PTE} \quad (30)$$ + +- 2) The top limit $U_{NH}$ of the varistor voltage tolerance and the protection level $U_P$ of the selected MOV should be in accordance with equation 31. + +$$U_{NH} < U_P / R_{RES} \quad (31)$$ + +Where: $R_{RES}$ is the residual voltage ratio of the selected MOV at specified pulse peak which is available from pulse V-I characteristic formulae of the MOV. + +- 3) From viewpoint of production, at least 5% tolerance should be allowed for varistor voltage, so that: + +$$U_{NL} < 0.95 U_{NH} \quad (32)$$ + +- 4) From viewpoint of service life, the low limit $U_{NL}$ should be not less than the MCOV + +Power frequency circuitry: $U_{NL} \geq 1.41 U_C$ + +DC power circuitry: $U_{NL} \geq U_{CD}$ + +Other power circuitry: $U_{NL} \geq U_{Cx}$ + +- 5) According to clause G.10.2 of [IEC 62368-1], the MCOV of an MOV should be not less than 1.25 times $U_R$ , the $U_R$ refers to the rated voltage of protected equipment or the upper limit of the rated voltage range. + +$$U_C \geq 1.25 U_R \quad (33)$$ + +Generally speaking: + +$$U_C \geq k U_{0M} \quad (k > 1) \quad (34)$$ + +Where: $U_{0M}$ is the possible maximum value of the system voltage, the factor $k$ depends on the voltage stability of the system into which the MOV being connected, the smaller system voltage variation corresponding to smaller factor $k$ . + +There are two basic conflicts involved in application design of MOVs: + +- Conflict 1: low limiting voltage needs high non-linearity + - high energy rating needs low non-linearity +- Conflict 2: long service life and high reliability under MCOV and TOV stresses needs high varistor voltage $U_N$ , + - low limiting voltage needs low $U_N$ + +Therefore, there has to be a trade-off between them. + +## 13.6 Series connection and parallel connection examples + +### 13.6.1 Series connection + +MOVs are connected in series to have a higher voltage rating, or to achieve higher performance. + +In Figure 34 most of TOV event voltage will occur across VRL, while during an impulse event most of the voltage will be across VRh due to conduction of the gas discharge tube (GDT). + +![Circuit diagram showing a series connection of two MOVs (VRL and VRh) and a gas discharge tube (GDT) in parallel with the VRL MOV. The input voltage is Us, and the output voltage is Up. The diagram is labeled K.128(18)_F34.](7fb00557d53d1f3a74f2c39a98c36fd6_img.jpg) + +The diagram shows a circuit with an input voltage source $U_s$ connected to a series combination of two MOVs, VRL and VRh. A gas discharge tube (GDT) is connected in parallel with the VRL MOV. The output voltage is $U_p$ . The diagram is labeled K.128(18)\_F34. + +Circuit diagram showing a series connection of two MOVs (VRL and VRh) and a gas discharge tube (GDT) in parallel with the VRL MOV. The input voltage is Us, and the output voltage is Up. The diagram is labeled K.128(18)\_F34. + +**Figure 34 – Improved TOV endurance by series connection of high $\alpha$ MOV (VRh) and a low $\alpha$ MOV (VRL)** + +### 13.6.2 Parallel connection + +Parallel connection of one or more units is often used in MOV technology, the aim of which is: + +- to reduce residual voltage, or +- to increase the withstanding ratings of impulse current or energy, or +- to provide back-up protection, or +- to provide special performance. + +The paralleled units may or may not be identical. The prime requirement of a parallel assembly is to achieve the correct current sharing between each individual unit so that the rated values are not exceeded for the entire service life. A design approach can be to calculate, using the V-I characteristic formulas, the current sharing over a range of impulse voltages to check that the specified ratings are not exceeded and the required current capability is achieved. The example below shows how this is done. + +In this example the parallel assembly consists of two units that have the below impulse V-I formulas for a 8/20 current peak range of 30 A to 20 kA. The maximum allowable current peak is 40 kA 8/20 for Unit 1, and 3.5 kA 8/20 for Unit 2. + +$$\text{Unit 1, 34 mm}\times\text{34 mm, } U_{n0}=620\text{V, } U_1 = 1702 \cdot I_1^{B_1}, B_1 = -0.247 + 0.0544 \times \log I$$ + +$$\text{Unit 2, } \phi 10 \text{ mm, } U_{n0}=560\text{V, } U_2 = 1091 \cdot I_2^{B_2}, B_2 = -0.181 + 0.0666 \times \log I$$ + +Using equation 35, two V-I formulas result from either using $x_1$ or $x_2$ for $x$ . Using eight selected voltages from 950V to 1650V, the current sharing of the two units can be calculated. The results are given in Table 3 + +$$I = 10^x \tag{35}$$ + +where: + +$$x_1 = \frac{0.247 + \sqrt{(0.247)^2 + 4 \times 0.0544 \times \log(U/1702)}}{2 \times 0.0544} \tag{36}$$ + +$$x_2 = \frac{0.181 + \sqrt{(0.181)^2 + 4 \times 0.0666 \times \log(U/1091)}}{2 \times 0.0666} \tag{37}$$ + +**Table 3 – Calculated current sharing** + +| Impulse voltage (V) | Current in Unit 2 $I_2$ (A) | Current in Unit 1 $I_1$ (A) | Total current $I_2 + I_1$ (A) | Current ratio $I_1/I_2$ | +|---------------------|-----------------------------|-----------------------------|-------------------------------|-------------------------| +| 950 | 216.1 | 958.9 | 1175 | 4.43 | +| 1050 | 422.9 | 2591. | 3014 | 6.13 | +| 1150 | 695.4 | 4974 | 5669 | 7.15 | +| 1250 | 1037 | 8201 | 9238 | 7.91 | +| 1350 | 1449 | 12344 | 13792 | 8.52 | +| 1450 | 1932. | 17461 | 19393. | 9.04 | +| 1550 | 2488. | 23600. | 26089 | 9.48 | +| 1650 | 3117. | 30802. | 33919 | 9.88 | + +It is seen from Table 3 that: + +- If the total current is about 26 kA (greater than the expected maximum value of 20 kA), the current in Unit 2 is less than 2.5 kA while its rating being 3.5 kA, so it is safe. +- The current ratio of Unit 1 to Unit 2 is increasing with total current increasing. + +# Appendix I + +## Peak displacement and negative dynamic resistance + +(This appendix does not form an integral part of this Recommendation.) + +These peak displacement and negative dynamic resistance behaviours are due to the MOV non-linearity and can be mathematically explained by [b-Wang], page 56. + +In the case of the peak displacement as current ( $I$ ) through an MOV is a time variable, its resistance ( $R$ ) is also a time variable, making the voltage rate ( $dU/dt$ ) expression: + +$$\frac{dU}{dt} = \frac{d(I \times R)}{dt} = R \frac{dI}{dt} + I \frac{dR}{dt} \quad (\text{I.1})$$ + +If $R \frac{dI}{dt}$ is plus, $I \frac{dR}{dt}$ must be minus, or vice versa. + +At current peak point $\frac{dI}{dt}$ must be zero, hence + +$$\frac{dU}{dt} = I \frac{dR}{dt} \quad (\text{I.2})$$ + +At voltage peak point $\frac{dU}{dt}$ must be zero, hence + +$$R \frac{dI}{dt} + I \frac{dR}{dt} = 0 \quad (\text{I.3})$$ + +Equation I.2 and equation I.3 cannot be fulfilled at the same time instant, which why the peak displacement happens. + +For the case of the negative dynamic resistance the following incremental equation can be written: + +$$du = d(i \times r) = r \cdot di + i \cdot dr \quad (\text{I.4})$$ + +Taking $dr$ always having an opposite sign of $di$ into account, the following conclusions can be reached: + +If $|r \cdot di| < |i \cdot dr|$ , then $du$ and $di$ are in the opposite sign, i.e., negative dynamic resistance. + +If $|r \cdot di| = |i \cdot dr|$ , then $du = 0$ , the voltage remains unchanged despite the current variation. + +If $|r \cdot di| > |i \cdot dr|$ , then $du$ and $di$ are in the same sign, i.e., positive dynamic resistance, which is the expected MOV operation. + +The above discussions show that both the peak displacement and the negative dynamic resistance are the result of the MOV's resistance non-linearity. + +## Bibliography + +- [b-ITU-T K.96] Recommendation ITU-T K.96 (2014), *Surge protective components: Overview of surge mitigation functions and technologies.* +- [b-IEC 60099-4] IEC 60099-4 (2014), *Surge arresters – Part 4: Metal-oxide surge arresters without gaps for a.c. systems.* +- [b-IEC 60364-4-44] IEC 60364-4-44 (2007), *Low-voltage electrical installations – Part 4-44: Protection for safety – Protection against voltage disturbances and electromagnetic disturbances.* +- [b-IEC 60664] IEC 60664 (2018), *Insulation coordination for equipment within low-voltage systems – All parts.* +- [b-IEC 61000-4-5] IEC 61000-4-5 (2014), *Electromagnetic compatibility (EMC) – Part 4-5: Testing and measurement techniques – Surge immunity test.* +- [b-IEC 62368-1] IEC 62368-1 (2014), *Audio/video, information and communication technology equipment – Part 1: Safety requirements.* +- [b-IEEE C62.33] IEEE Std C62.33 (1982), *IEEE Standard Test Specifications for Varistor Surge-Protective Devices.* +- [b-Ding] Ding Liuhua, Shu Jing (2010), *Experimental study of the life distribution of ZnO varistors subjected to surge current cycles*, Electronic Components and Materials, pp. 36-38. +- [b-Panasonic] Panasonic Electronic Component Co. (1981), *Ceramic Department Application Manual of 'ZNR'* (2nd. edition). +- [b-Wang] Wang zhen-lin, Li Sheng-tao (2009), *Engineering and Application of Zinc Oxide Voltage Dependent Ceramics [M]*, Beijing: Science Press. +- [b-Wu] Wu wei-han, He jin-liang, Gao Yu-ming (1998), *Properties and Applications of Nonlinear Metal Oxide Varistors [M]*, Beijing, Qing Hua University Press, p.56. +- [b-Xu] Ying Xu, Shiheng Xu (2006), *Overvoltage Protection and Insulation Coordination for A.C. Power System*, Beijing, China Electric Power Press, p.59. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages 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b/marked/K/T-REC-K.129-201801-I_PDF-E/raw.md @@ -0,0 +1,999 @@ + + +International Telecommunication Union + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.129** + +(01/2018) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Characteristics and ratings of silicon PN +junction voltage clamping components used for +the protection of telecommunication +installations** + +Recommendation ITU-T K.129 + +ITU-T + +![ITU logo: A globe with a red lightning bolt striking it, next to the text 'ITU International Telecommunication Union'.](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with a red lightning bolt striking it from the top right. To the right of the globe, the text "ITU" is written in a bold, blue, sans-serif font. Below "ITU", the words "International Telecommunication Union" are written in a smaller, blue, sans-serif font. + +ITU logo: A globe with a red lightning bolt striking it, next to the text 'ITU International Telecommunication Union'. + + + +# Recommendation ITU-T K.129 + +# Characteristics and ratings of silicon PN junction voltage clamping components used for the protection of telecommunication installations + +## Summary + +Recommendation ITU-T K.129 defines the basic electrical parameters to be met by silicon PN junction voltage clamping components used for the protection of telecommunication equipment or lines from surges. Examples of equipment include those located within a telecommunication centre, customer premise, access or trunk network. It is intended that this Recommendation be used for the harmonization of existing or future specifications issued by PN diode surge protective component manufacturers, telecommunication equipment manufacturers, administrators or network operators. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.129 | 2018-01-13 | 5 | 11.1002/1000/13452 | + +## Keywords + +Avalanche breakdown, electrical characteristics, electrical ratings, fold-back, forward conduction, overvoltage protection, punch-through, surge protective component (SPC), test methods, Zener breakdown. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2018 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|-----|-----------------------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 3.1 | Terms defined elsewhere ..... | 1 | +| 3.2 | Terms defined in this Recommendation..... | 4 | +| 4 | Abbreviations and acronyms ..... | 5 | +| 5 | Conventions ..... | 5 | +| 5.1 | Letter symbols ..... | 5 | +| 5.2 | Component graphical symbols ..... | 6 | +| 6 | Environments..... | 7 | +| 6.1 | Normal service conditions ..... | 7 | +| 6.2 | Storage temperature range, $T_{\text{stgmin}}$ to $T_{\text{stgmax}}$ ..... | 8 | +| 6.3 | Lead soldering temperature, $T_{\text{lmax}}$ ..... | 8 | +| 7 | Essential characteristics and ratings ..... | 8 | +| 7.1 | General ..... | 8 | +| 7.2 | Electrical characteristics ..... | 8 | +| 7.3 | Thermal ratings..... | 10 | +| 7.4 | Electrical ratings ..... | 11 | +| 8 | Measuring and test methods ..... | 11 | +| 8.1 | Mounting and ambient conditions ..... | 11 | +| 8.2 | Test circuits ..... | 11 | +| 8.3 | Measuring methods for electrical characteristics ..... | 12 | +| 8.4 | Measuring methods for thermal characteristics..... | 16 | +| 8.5 | Verification test methods for ratings (limiting values)..... | 17 | +| 9 | Mechanical requirements and identification..... | 18 | +| 9.1 | Robustness of terminations..... | 18 | +| 9.2 | Solderability ..... | 18 | +| 9.3 | Marking ..... | 18 | +| 9.4 | Documentation ..... | 19 | +| | Bibliography..... | 20 | + + + +# Recommendation ITU-T K.129 + +# Characteristics and ratings of silicon PN junction voltage clamping components used for the protection of telecommunication installations + +# 1 Scope + +Silicon PN-junction surge protective components (SPCs) are special silicon diodes designed to limit overvoltages and divert surge currents by a voltage clamping action. This Recommendation applies to silicon PN-junction SPCs used in surge protective devices (SPDs) and telecommunication equipment ports to provide overvoltage protection for installations during lightning surges and alternating current (AC) power faults, in accordance with [b-ITU-T K.11]. Telecommunication equipment port test levels and criteria are defined by [b-ITU-T K.20], [b-ITU-T K.21] and [b-ITU-T K.45], as appropriate and are supported by [b-ITU-T K.44] with test circuit details and application guidance. In conjunction, [ITU-T K.103] should be read as it explains the parameters measured or verified in this Recommendation. + +The following PN-junction component technologies are covered: + +- Zener breakdown; +- avalanche breakdown; +- fold-back; +- punch-through; +- forward conduction. + +This Recommendation contains information on: + +- a) terminology; +- b) letter and circuit symbols; +- c) essential electrical ratings and characteristics; +- d) rating verification and characteristic measurement; +- f) mechanical requirements and identification. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T K.103] Recommendation ITU-T K.103 (2015), *Surge protective component application guide – Silicon PN junction components*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 acceptor** [b-IEC IEV], definition 521-02-39: Imperfection in a crystal lattice which, when it is predominant, permits hole conduction by the acceptance of electrons. + +- 3.1.2 ambient temperature** [b-IEC TR 62240-1]: Temperature of the environment in which a semiconductor component is operating. +- 3.1.3 avalanche breakdown (of a PN junction)** [b-IEC IEV], definition 521-05-07: Breakdown that is caused by the cumulative multiplication of charge carriers in a semi-conductor under the action of a strong electric field which causes some carriers to gain enough energy to liberate new hole-electron pairs by ionization. +- 3.1.4 avalanche voltage** [b-IEC IEV], definition 521-05-08: Applied voltage at which avalanche breakdown occurs. +- 3.1.5 bidirectional transistor** [b-IEC IEV], definition 521-04-49: Transistor which has substantially the same electrical characteristics when the terminals normally designated as emitter and collector are interchanged. +- 3.1.6 bipolar junction transistor** [b-IEC IEV], definition 521-04-47: Transistor having at least two junctions and whose functioning depends on both majority carriers and minority carriers. +- 3.1.7 breakdown (of a reverse-biased PN junction)** [b-IEC IEV], definition 521-05-06: Phenomenon, the initiation of which is observed as a transition from a state of high dynamic resistance to a state of substantially lower dynamic resistance for increasing magnitude of reverse current. +- 3.1.8 breakdown voltage, $V_{(BR)}$** [b-IEC 60747-2]: Voltage in the region where breakdown occurs. +- 3.1.9 case temperature** [b-IEC 60747-1]: Temperature of a reference point, on or near the surface of the case. +- 3.1.10 conduction electron** [b-IEC IEV], definition 521-02-14: Electron in the conduction band of a semiconductor, which is free to flow under the action of an electric field. +- 3.1.11 donor** [b-IEC IEV], definition 521-02-38: Imperfection in a crystal lattice which, when it is predominant, permits electron conduction by the donation of electrons. +- 3.1.12 extrinsic semiconductor** [b-IEC IEV], definition 521-02-08: Semiconductor in which charge carrier concentration depends upon impurities or other imperfections. +- 3.1.13 forward current, $I_F$** [b-IEC 60747-2]: Current flowing through the diode in forward direction. +- 3.1.14 forward direction (of a PN junction)** [b-IEC IEV], definition 521-05-03: Direction of current that results when the P-type semiconductor region is at a positive voltage relative to the N-type region. +- 3.1.15 forward recovery voltage, $V_{FR}$** [b-IEC 60747-2]: Varying voltage occurring during the forward recovery time after instantaneous switching from zero or a specified reverse voltage to a specified forward current. +- 3.1.16 forward voltage, $V_F$** [b-IEC 60747-2]: Voltage across the terminals which results from the flow of current in the forward direction. +- 3.1.17 hole conduction** [b-IEC IEV], definition 521-02-18: Conduction in a semiconductor, in which holes in a crystal lattice are propagated through the lattice under the influence of an electric field. +- 3.1.18 Kelvin measurement** [b-IEC 62624]: Four-wire electrical resistance technique that uses separate contacts for measuring voltage across a device from that used to apply a known current through the device. + +NOTE 1 – This separation minimizes current flow through the voltage probes, which minimizes errors due to contact or lead resistance. + +NOTE 2 – Used for characterization of materials with electrical resistances comparable to or lower than the leads and contacts. + +**3.1.19 lead temperature** [b-IEC 60747-1]: Temperature of a reference point, on or near the surface of a specified component lead. + +**3.1.20 N-type semiconductor** [b-IEC IEV], definition 521-02-09: Extrinsic semiconductor in which the conduction electron density exceeds the hole density. + +**3.1.21 peak pulse current (impulse discharge current)** [b-IEC 61000-5-5]: Peak value of a specified current waveform. + +**3.1.22 PN junction** [b-IEC IEV], definition 521-02-78: Junction between P and N type semiconductor materials. + +**3.1.23 P-type semiconductor** [b-IEC IEV], definition 521-02-10: Extrinsic semiconductor in which the hole density exceeds the conduction electron density. + +**3.1.24 punch-through (between two PN junctions)** [b-IEC IEV], definition 521-05-12: Contact between the space charge regions of two PN junctions as a result of widening of one or both of them. + +**3.1.25 reverse current, $I_R$** [b-IEC 60747-2]: Current flowing through the diode when reverse voltage is applied. + +**3.1.26 reverse direction (of a PN junction)** [b-IEC IEV], definition 521-05-04: Direction of current that results when the N-type semiconductor region is at a positive voltage relative to the P-type region. + +**3.1.27 reverse voltage, $V_R$** [b-IEC 60747-2]: Constant voltage applied to a diode in the reverse direction. + +NOTE – This term normally applies to the portion of the reverse characteristic before breakdown occurs. + +**3.1.28 space-charge region** [b-IEC IEV], definition 521-02-79: Region in which the net charge density is not zero. + +NOTE – The net charge is caused by electrons, holes, ionized acceptors and donors. + +**3.1.29 storage temperature** [b-IEC 60747-1]: Temperature at which the device may be stored without any voltage being applied. + +**3.1.30 temperature coefficient of breakdown voltage $\alpha V_{BR}$** [b-IEC 61643-321]: Ratio of the change in breakdown voltage $V_{BR}$ to changes in temperature. + +NOTE – Expressed as either millivolts per degree Kelvin or per cent per degree Kelvin (mV/K or %/K). + +**3.1.31 thermal resistance** [b-IEC IEV], definition 521-05-13: Quotient of the difference between the virtual temperature of the device and the temperature of a stated external reference point, by the steady-state power dissipation in the device. + +**3.1.32 total capacitance** [b-IEC 60747-3]: Capacitance at the diode terminals, measured under specified bias conditions. + +**3.1.33 transient thermal impedance** [b-IEC 60747-1]: Quotient of: + +- a) the change in temperature difference between two specified points or regions at the end of a time interval, and +- b) the step-function change in power dissipation beginning at that time interval which causes the change in temperature difference. + +NOTE – The term used in practice must indicate the two specified points or regions, for example, as in "junction-case transient thermal impedance". The use of the shortened term "transient thermal impedance" is permitted only if no ambiguity is likely to occur. + +**3.1.34 Zener breakdown (of a PN junction)** [b-IEC IEV], definition 521-05-09: Breakdown caused by the transition of electrons from the valence band to the conduction band due to tunnel action under the influence of a strong electric field in a PN junction. + +**3.1.35 Zener voltage** [b-IEC IEV], definition 521-05-10: Minimum voltage across a PN junction at which Zener breakdown occurs. + +## **3.2 Terms defined in this Recommendation** + +This Recommendation defines the following terms: + +**3.2.1 clamping (limiting) voltage:** Breakdown voltage developed across the diode at a specified impulse current. + +NOTE – Normally the maximum value of clamping voltage is reported for the rated value of peak pulse current. + +**3.2.2 discrete (semiconductor) component:** Semiconductor component that is specified to perform an elementary function and that is not divisible into separate components functional in themselves. (modified version of [b-IEC IEV], definition 521-04-02) + +NOTE – There is no clear delimitation possible between discrete components and integrated circuits. In principle, a discrete component consists of a single circuit element only. However, a component sold and specified as a discrete component may internally consist of more than one circuit element. + +**3.2.3 fold-back breakdown (of a bidirectional bipolar junction transistor diode):** Re-entrant breakdown characteristic caused by transistor action after the initiation of breakdown producing a region of negative dynamic resistance before reverting back to a low positive dynamic resistance condition. + +NOTE – The negative resistance region and its voltage range is only pronounced for breakdown voltages in excess of about 20 V. + +**3.2.4 fold-back diode:** Bidirectional bipolar junction transistor packaged with only the collector and emitter terminals made available. + +**3.2.5 punch-through voltage:** Low-current peak voltage marking the start of the diode clamping characteristic. + +NOTE – This punch-through diode term may also be applied to fold-back diodes. + +**3.2.6 semiconductor component:** Component whose essential characteristics are due to the flow of charge carriers within a semi-conductor. (modified version of [b-IEC IEV], definition 521-04-01) + +NOTE – The definition includes components whose essential characteristics are only in part due to the flow of charge carriers in a semiconductor but that are considered as semiconductor components for the purpose of specification. + +**3.2.7 (semiconductor) diode:** Two-terminal semiconductor component having an asymmetrical voltage-current characteristic. (modified version of [b-IEC IEV], definition 521-04-03) + +NOTE 1 – Unless otherwise qualified, this term usually means a device with the voltage-current characteristic typical of a single PN junction. + +NOTE 2 – Voltage clamping diodes are normally classified by clamping phenomenon; Zener, avalanche, fold-back, punch-through and forward conduction. Acronyms such as ABD (avalanche breakdown diode), TVS (transient voltage suppressor) and SAD (silicon avalanche diode) may also be used. + +**3.2.8 snap-back voltage:** Lowest voltage in the clamping characteristic after the punch-through voltage occurs. + +NOTE – This punch-through diode term may also be applied to fold-back diodes. + +**3.2.9 terminal (of a semiconductor component):** Conductive element provided for external connection. (modified version of [b-IEC IEV], definition 521-05-02) + +**3.2.10 total power dissipation:** Rated (maximum) value of the power that can be continuously dissipation by the diode at a specified ambient, case or lead temperature without exceeding the maximum rated junction temperature. + +**3.2.11 virtual junction temperature, internal equivalent temperature (of a semiconductor component):** Theoretical temperature which is based on a simplified representation of the thermal and electrical behaviour of the semiconductor device. (modified version of [b-IEC IEV], definition 521-05-14) + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|-------------------------------------------| +| ABD | Avalanche Breakdown Device | +| AC | Alternating Current | +| DC | Direct Current | +| ICT | Information and Communication Technology | +| SAD | Silicon Avalanche Diode | +| SPC | Surge Protective Component | +| TVS | Transient Voltage Suppressor | +| WEEE | Waste Electrical and Electronic Equipment | + +# 5 Conventions + +## 5.1 Letter symbols + +The general rules and letter symbols of clause 4 of [b-IEC 60747-1] apply to this Recommendation. To indicate a limit or rated value, the letter symbol subscript appends M or max to indicate maximum and min to indicate a minimum. + +| | | +|----------------------|---------------------------------------------------------------| +| $C_{\text{tot}}$ | Total capacitance | +| $dI_F/dt$ | Rate of forward current rise | +| $I_{(\text{BR})}$ | Breakdown current | +| $I_F$ | Forward current | +| $I_{\text{PP}}$ | Peak pulse current | +| $I_{\text{PP}}$ | Peak pulse current | +| $I_R$ | Reverse current | +| $P_{\text{PP}}$ | Maximum peak pulse power | +| $P_{\text{tot}}$ | Total power dissipation | +| $R_{\text{th(j-a)}}$ | Thermal resistance junction to ambient | +| $R_{\text{th(j-c)}}$ | Thermal resistance junction to case | +| $R_{\text{th(j-l)}}$ | Thermal resistance junction to lead | +| $T_a$ | Operating ambient temperature | +| $T_c$ | Case temperature | +| $T_j$ | Virtual junction temperature, internal equivalent temperature | + +| | | +|--------------------------|----------------------------------------------------------------| +| $T_1$ | Lead temperature | +| $T_{\text{stg}}$ | Storage temperature | +| $V_{(\text{BR})}$ | Breakdown voltage | +| $V_{(\text{PT})}$ | Punch-through voltage | +| $V_{(\text{SB})}$ | Snap-back voltage | +| $V_C$ | Clamping voltage | +| $V_F$ | Forward biased PN junction voltage | +| $V_{\text{FRM}}$ | Peak forward recovery voltage | +| $V_R$ | Reverse working voltage | +| $V_{\text{RWM}}$ | Stand-off or maximum reverse working voltage | +| $Z_{\text{th(j-a)(t)}}$ | Transient thermal impedance, junction to ambient | +| $Z_{\text{th(j-c)(t)}}$ | Transient thermal impedance, junction to case | +| $Z_{\text{th(j-l)(t)}}$ | Transient thermal impedance, junction to lead | +| $\alpha V_{(\text{BR})}$ | Temperature coefficient of breakdown voltage $V_{(\text{BR})}$ | + +## 5.2 Component graphical symbols + +### 5.2.1 General + +This Recommendation uses the following SPC graphical symbols from [b-IEC 60617]: + +### 5.2.2 Single PN-junction symbols + +![General symbol for a semiconductor diode, consisting of a triangle pointing to a vertical line, with leads extending from both sides.](e159e9f78612406820a4d40e26e01413_img.jpg) + +K.129(18)\_F5-1 + +General symbol for a semiconductor diode, consisting of a triangle pointing to a vertical line, with leads extending from both sides. + +Figure 5-1 – Semiconductor diode, general symbol (symbol S00641) + +![Symbol for a unidirectional breakdown diode, which is the general diode symbol with an additional L-shaped line at the cathode end.](53298644c66fa3fca81d6eec654afec5_img.jpg) + +K.129(18)\_F5-2 + +Symbol for a unidirectional breakdown diode, which is the general diode symbol with an additional L-shaped line at the cathode end. + +Figure 5-2 – Breakdown diode, unidirectional (symbol S00646) + +### 5.2.3 Multiple PN-junction symbols + +![Symbol for a bidirectional breakdown diode, which is the general diode symbol with an additional L-shaped line at the anode end.](10d19f166f9b7f5961f09f8041896943_img.jpg) + +K.129(18)\_F5-3 + +Symbol for a bidirectional breakdown diode, which is the general diode symbol with an additional L-shaped line at the anode end. + +Figure 5-3 – Breakdown diode, bidirectional (symbol S00647) + +![Figure 5-4: Examples of diode arrays. The diagram shows three different diode array configurations. The first is a single diode. The second is a bridge rectifier consisting of four diodes. The third is a more complex array with two vertical columns of four diodes each, connected in a bridge-like configuration with multiple input and output terminals.](af7916c89a458fdab6c3f443217388ae_img.jpg) + +Figure 5-4: Examples of diode arrays. The diagram shows three different diode array configurations. The first is a single diode. The second is a bridge rectifier consisting of four diodes. The third is a more complex array with two vertical columns of four diodes each, connected in a bridge-like configuration with multiple input and output terminals. + +K.129(18)\_F5-4 + +**Figure 5-4 – Examples of diode arrays** + +![Figure 5-5: Examples of breakdown diodes combined with diodes and diode arrays. The diagram shows five different configurations. The top row shows three individual breakdown diode symbols. The bottom row shows two more complex arrays: the first consists of three vertical branches, each with a breakdown diode and a regular diode in series; the second is a larger array with five vertical branches, each containing a breakdown diode and a regular diode.](ff0952ef692c9d960ce5f6708bcc9711_img.jpg) + +Figure 5-5: Examples of breakdown diodes combined with diodes and diode arrays. The diagram shows five different configurations. The top row shows three individual breakdown diode symbols. The bottom row shows two more complex arrays: the first consists of three vertical branches, each with a breakdown diode and a regular diode in series; the second is a larger array with five vertical branches, each containing a breakdown diode and a regular diode. + +K.129(18)\_F5-5 + +**Figure 5-5 – Examples of breakdown diodes combined with diodes and diode arrays** + +# 6 Environments + +The preferred climatic conditions are taken from the IEC classification of environmental conditions standards and the storage temperature ranges are taken from the IEC semiconductor devices standards. + +## 6.1 Normal service conditions + +This standard is for components mounted in stationary equipment and device installations that are weather-protected, see [b-IEC 60721-3-3]. The two preferred microclimates within the products are selected from [b-IEC 60721-3-9]. + +### 6.1.1 Normal microclimate + +- ambient air temperature within the range of 0°C to 70°C; +- air pressure within the range of 80 kPa to 106 kPa; +- relative humidity within the range of 25% to 75%. + +### 6.1.2 Extended microclimate + +- ambient air temperature within the range of –40°C to 85°C; + +- air pressure within the range of 70 kPa to 106 kPa; +- relative humidity 10% to 95%. + +## 6.2 Storage temperature range, $T_{\text{stgmin}}$ to $T_{\text{stgmax}}$ + +The temperatures over which a component can be stored without any voltage applied has the following preferred temperature ranges (selected from [b-IEC 60747-1] and [b-IEC 60749-1]): + +- a) 0°C to 125°C; +- b) –55°C to 125°C; +- c) –65°C to 150°C. + +NOTE – In some cases the storage temperature range may be limited by the component shipping containers and not by the component itself. + +## 6.3 Lead soldering temperature, $T_{\text{Imax}}$ + +Legislation, such as the waste electrical and electronic equipment (WEEE) directive and restriction of hazardous substances (RoHS) directive in the European Union, has accelerated the use of lead-free soldering. Removing the lead from solder results in increased soldering temperatures and component manufactures now routinely specify maximum soldering conditions in terms of component lead temperature, $T_{\text{Imax}}$ , and temperature duration time, $t_{\text{Imax}}$ , see [b-IEC 60068-2-20]. Examples are 260°C for 10 s and 260°C for 40 s. + +# 7 Essential characteristics and ratings + +## 7.1 General + +For compatibility with general purpose breakdown diodes, the format of this clause follows that of [b-IEC 60747-3]. Many of the ratings and characteristics are required to be quoted at a temperature of 25°C and at one other specified temperature. + +## 7.2 Electrical characteristics + +### 7.2.1 PN-junction structure electrical characteristics + +#### 7.2.1.1 Single PN-junction + +This classification covers forward biased diodes, reverse biased diodes, Zener breakdown diodes and avalanche breakdown diodes. Symmetrical breakdown diodes are made by the series connection of a PN-junction and a NP-junction giving a limiting voltage of $V_{(\text{BR})} + V_{\text{F}}$ . Such arrangements can be made in a single chip. The electrical characteristics and symbol identification for a forward conducting diode and a breakdown diode are shown in Figure 7-1 and Figure 7-2, respectively. + +![Figure 7-1: Diode characteristic graph showing forward and reverse blocking characteristics.](71ab4df17511d75261da8d462d643b1a_img.jpg) + +This graph shows the current ( $i$ ) versus voltage ( $v$ ) characteristic of a diode. The vertical axis represents current, with positive values labeled $I_{PP}$ and $I_F$ , and negative values labeled $I_R$ and $-i$ . The horizontal axis represents voltage, with a break in the scale. The forward characteristic curve starts at the origin and rises steeply, passing through a point marked $V_F$ and $I_F$ , and continuing towards $I_{PP}$ . The reverse blocking characteristic curve is shown in the third quadrant, starting from a voltage $V_R$ and current $I_R$ , and remaining very close to the voltage axis. The label 'Forward characteristic' is placed near the first curve, and 'Reverse blocking characteristic' is placed near the second curve. The code 'K.129(18)\_F7-1' is at the bottom right. + +Figure 7-1: Diode characteristic graph showing forward and reverse blocking characteristics. + +Figure 7-1 – Diode characteristic + +![Figure 7-2: Breakdown diode characteristic graph showing current versus voltage with breakdown region.](177e8bc1c595b7fe3461d9919f87e044_img.jpg) + +This graph shows the current versus voltage characteristic of a breakdown diode. The vertical axis is labeled 'Current' and has markings for $I_{PP}$ , $I_{(BR)}$ , and $I_R$ . The horizontal axis is labeled 'Voltage' and has markings for $V_{RWM}$ , $V_{(BR)}$ , and $V_C$ . The curve shows a very low current $I_R$ until it reaches the breakdown voltage $V_{(BR)}$ , where it rises sharply. A horizontal line at $I_{(BR)}$ indicates the start of the breakdown region. The current continues to rise towards $I_{PP}$ as voltage increases towards $V_C$ . The code 'K.129(18)\_F7-2' is at the bottom right. + +Figure 7-2: Breakdown diode characteristic graph showing current versus voltage with breakdown region. + +Figure 7-2 – Breakdown diode characteristic + +#### 7.2.1.2 Multiple PN-junction + +This classification for transistor-like structures covers punch-through diodes and fold-back diodes. The voltage limiting characteristic for these types is strongly re-entrant. The electrical characteristic and symbol identification is shown in Figure 7-3. + +![Figure 7-3: Punch-through diode and fold-back diode characteristic graph. The vertical axis is labeled 'Current' and the horizontal axis is labeled 'Voltage'. The graph shows a curve that starts at a low current $I_R$ and remains nearly constant until it reaches a voltage $V_{RWM}$. At $V_{RWM}$, the current begins to increase. It reaches a peak current $I_{PP}$ at a voltage $V_{PT}$. Beyond $V_{PT}$, the current decreases as voltage increases, reaching a minimum current at $V_{SB}$. From $V_{SB}$, the current increases again, reaching $I_{PP}$ at $V_C$. The curve then continues to rise. The label 'K.129(18)_F7-3' is at the bottom right.](ad29805cd4f64ad2828e14feb66de664_img.jpg) + +Figure 7-3: Punch-through diode and fold-back diode characteristic graph. The vertical axis is labeled 'Current' and the horizontal axis is labeled 'Voltage'. The graph shows a curve that starts at a low current \$I\_R\$ and remains nearly constant until it reaches a voltage \$V\_{RWM}\$. At \$V\_{RWM}\$, the current begins to increase. It reaches a peak current \$I\_{PP}\$ at a voltage \$V\_{PT}\$. Beyond \$V\_{PT}\$, the current decreases as voltage increases, reaching a minimum current at \$V\_{SB}\$. From \$V\_{SB}\$, the current increases again, reaching \$I\_{PP}\$ at \$V\_C\$. The curve then continues to rise. The label 'K.129(18)\_F7-3' is at the bottom right. + +Figure 7-3 – Punch-through diode and fold-back diode characteristic + +### 7.2.2 Reverse current, $I_R$ + +Maximum value at a specified reverse voltage. + +### 7.2.3 Breakdown voltage, $V_{(BR)}$ + +Minimum value for a specified current. + +### 7.2.4 Clamping voltage, $V_C$ + +Maximum value for specified current. + +### 7.2.5 Punch-through voltage, $V_{(PT)}$ + +Maximum value. + +### 7.2.6 Snap-back voltage, $V_{(SB)}$ + +Minimum value. + +### 7.2.7 Forward biased PN junction voltage, $V_F$ + +Maximum value at specified forward current. + +### 7.2.8 Total capacitance, $C_{tot}$ + +Maximum value for specified terminal and electrical conditions. + +### 7.2.9 Thermal resistance ( $R_{th}$ ) + +Maximum value or a graph of maximum total power dissipation as a function of temperature over the range of operating temperatures. + +### 7.2.10 Thermal impedance ( $Z_{th}$ ) + +A graph of thermal impedance as a function of time up to the thermal resistance value. + +## 7.3 Thermal ratings + +### 7.3.1 Storage temperature ( $T_{stg}$ ) + +Minimum and maximum values. + +### 7.3.2 Operating ambient temperature ( $T_a$ ) + +Minimum and maximum values. + +### 7.3.3 Lead soldering temperature, $T_l$ + +$T_{lmax}$ , and temperature duration time, $t_{lmax}$ . + +### 7.3.4 Virtual junction temperature, internal equivalent temperature, $T_J$ + +Maximum value. + +## 7.4 Electrical ratings + +### 7.4.1 Peak pulse current, $I_{PP}$ + +Maximum value at a specified ambient or sink or case and virtual junction temperature. + +### 7.4.2 Maximum peak pulse power, $P_{PP}$ + +Maximum value at specified current waveform. + +### 7.4.3 Total power dissipation, $P_{tot}$ + +Where thermal resistance is not given in the characteristics, maximum total power dissipation as a function of temperature over the range of operating temperatures shall be given. + +# 8 Measuring and test methods + +## 8.1 Mounting and ambient conditions + +For these tests, the component should be mounted as detailed in the product documentation. All room temperature electrical measurements, as well as recoveries followed by measurements, shall be carried out under the following conditions as recommended in clause 4, chapter 1 of [b-IEC 60749-1]: + +- temperature: 20°C to 30°C; +- relative humidity: 25% to 75%, where appropriate; +- air pressure: 80 kPa to 106 kPa. + +Referee tests shall be carried out under the following standard atmospheric conditions (see clause 4, chapter 1 of [b-IEC 60749-1]): + +- temperature: 24°C to 26°C; +- relative humidity: 25% to 75%; +- air pressure: 80 kPa to 106 kPa. + +## 8.2 Test circuits + +### 8.2.1 Pulsed current + +This circuit, shown in Figure 8-1, forces a current of defined polarity, amplitude and duration through the SPC under test. The SPC conduction voltage is digitally recorded at a defined time during the current pulse duration. + +![Circuit diagram for Figure 8-1: Current pulse, voltage measurement circuit. A current source labeled 'G' with a pulse waveform icon is connected in series with a voltmeter labeled 'V' and a component labeled 'SPC'. The current 'I' is shown entering the SPC. The diagram is labeled K.129(18)_F8-1.](7ec4ba01d21d0840c67e18d51aeb1415_img.jpg) + +The diagram shows a series circuit. On the left, a current source labeled 'G' is shown with a rectangular pulse waveform icon. A current 'I' is indicated entering the circuit. In the center, a voltmeter labeled 'V' is connected in parallel across the component on the right. The component on the right is labeled 'SPC'. The entire circuit is connected between two horizontal bus lines. Below the diagram, the text 'K.129(18)\_F8-1' is present. + +Circuit diagram for Figure 8-1: Current pulse, voltage measurement circuit. A current source labeled 'G' with a pulse waveform icon is connected in series with a voltmeter labeled 'V' and a component labeled 'SPC'. The current 'I' is shown entering the SPC. The diagram is labeled K.129(18)\_F8-1. + +Figure 8-1 – Current pulse, voltage measurement circuit + +### 8.2.2 Pulsed voltage + +This circuit, shown in Figure 8-2, applies a voltage of defined polarity, amplitude and duration to the SPC under test. The SPC current is digitally recorded at a defined time during the voltage pulse duration. + +![Figure 8-2: Voltage pulse, current measurement circuit. A generator (G) with a voltage pulse waveform (V) is connected in series with an ammeter (A) and a Semiconductor Power Component (SPC). The circuit is labeled K.129(18)_F8-2.](76b0cd79baaedd942af4dc42f2e764b8_img.jpg) + +Figure 8-2: Voltage pulse, current measurement circuit. A generator (G) with a voltage pulse waveform (V) is connected in series with an ammeter (A) and a Semiconductor Power Component (SPC). The circuit is labeled K.129(18)\_F8-2. + +**Figure 8-2 – Voltage pulse, current measurement circuit** + +### 8.2.3 Current ramp + +This circuit, shown in Figure 8-3, forces a current of defined polarity, amplitude and duration through the SPC under test. The SPC conduction voltage is digitally recorded at a defined time during the current pulse duration. + +![Figure 8-3: Current ramp, voltage measurement circuit. A generator (G) with a current ramp waveform (I) is connected in parallel with a voltmeter (V) and a Semiconductor Power Component (SPC). The circuit is labeled K.129(18)_F8-3.](9b9d2abd741ed4bafe7f78f89961c663_img.jpg) + +Figure 8-3: Current ramp, voltage measurement circuit. A generator (G) with a current ramp waveform (I) is connected in parallel with a voltmeter (V) and a Semiconductor Power Component (SPC). The circuit is labeled K.129(18)\_F8-3. + +**Figure 8-3 – Current ramp, voltage measurement circuit** + +### 8.2.4 Surge + +This circuit, shown in Figure 8-4, forces a surge impulse current of defined polarity, amplitude and waveshape through the SPC under test. The SPC conduction voltage is digitally recorded at a defined event during the current impulse duration. + +![Figure 8-4: Surge verification and voltage measurement circuit. A generator (G) with a surge impulse current waveform is connected in parallel with a voltmeter (V) and a Semiconductor Power Component (SPC). The circuit is labeled K.129(18)_F8-4.](51db757d054ce1ce83c436a3578b56ca_img.jpg) + +Figure 8-4: Surge verification and voltage measurement circuit. A generator (G) with a surge impulse current waveform is connected in parallel with a voltmeter (V) and a Semiconductor Power Component (SPC). The circuit is labeled K.129(18)\_F8-4. + +**Figure 8-4 – Surge verification and voltage measurement circuit** + +### 8.2.5 Capacitance + +![Figure 8-5: Kelvin connected capacitance measurement. A capacitance measuring equipment with terminals H_I, H_V, L_V, and L_I is connected to a Semiconductor Power Component (SPC). The equipment is labeled with V_D, f, V_d. The circuit is labeled K.129(18)_F8-5.](e928f4874ed492d3ad4c6fa2d29aedbc_img.jpg) + +Figure 8-5: Kelvin connected capacitance measurement. A capacitance measuring equipment with terminals H\_I, H\_V, L\_V, and L\_I is connected to a Semiconductor Power Component (SPC). The equipment is labeled with V\_D, f, V\_d. The circuit is labeled K.129(18)\_F8-5. + +**Figure 8-5 – Kelvin connected capacitance measurement** + +## 8.3 Measuring methods for electrical characteristics + +### 8.3.1 Stand-off or maximum reverse working voltage, $V_{RWM}$ + +#### a) Purpose + +To measure the reverse current of a diode under specified reverse voltage. + +- b) *Circuit diagram* + +Figure 8-2. + +- c) *Circuit description and requirements* + +Main elements are a voltage pulse generator of sufficient voltage and duration, a time or event programmable digital ammeter of sufficient sensitivity and the SPC under test. + +- d) *Measurement procedure* + +Using the circuit of Figure 8-2, a voltage pulse of $V_{RWM}$ is applied to the SPC, the current $I_R$ is measured after the initial capacitive charging current component is negligible. The same technique can be used for a diode to measure $I_R$ for a voltage pulse of $V_R$ , see Figure 7-1. + +- e) *Specified conditions* + +- ambient or case temperature ( $T_a$ , $T_c$ ); +- reverse voltage ( $V_{RWM}$ or $V_R$ ). + +### 8.3.2 Breakdown voltage, $V_{(BR)}$ + +- a) *Purpose* + +To measure the breakdown voltage of a diode at a specified current. + +- b) *Circuit diagram* + +Figure 8-1. + +- c) *Circuit description and requirements* + +Main elements are a current pulse generator of sufficient current and duration, a time or event programmable digital voltmeter of sufficient sensitivity and the SPC under test. + +- d) *Measurement procedure* + +Using the circuit of Figure 8-1 a current pulse of $I_{(BR)}$ is applied to the SPC, the voltage $V_{(BR)}$ is measured before any heating effects cause a change in the $V_{(BR)}$ value. + +- e) *Specified conditions* + +- ambient or case temperature ( $T_a$ , $T_c$ ); +- breakdown current ( $I_{(BR)}$ ). + +### 8.3.3 Clamping voltage $V_C$ + +- a) *Purpose* + +To measure the clamping voltage of a diode at a specified current. + +- b) *Circuit diagram* + +Figure 8-1 or Figure 8-4. + +- c) *Circuit description and requirements* + +Main elements are a current pulse generator of sufficient current and duration (Figure 8-1) or a defined surge impulse generator (Figure 8-4), a time or event programmable digital voltmeter of sufficient sensitivity and the SPC under test. + +- d) *Measurement procedure* + +Using the circuit of Figure 8-1 or Figure 8-4, a current pulse or impulse of $I_{PP}$ is applied to the SPC, the maximum voltage $V_C$ is measured after any transient effects have died out. + +- e) *Specified conditions* + +- ambient or case temperature ( $T_a$ , $T_c$ ); +- peak pulse current ( $I_{PP}$ ); + +- pulse duration used if appropriate; +- surge impulse used if appropriate. + +### 8.3.4 Punch-through voltage $V_{(PT)}$ + +#### a) Purpose + +To measure the peak low-current voltage of a diode. This applies to punch-through or fold-back diodes. + +#### b) Circuit diagram + +Figure 8-3. + +#### c) Circuit description and requirements + +Main elements are a current ramp generator of sufficient current and duration (Figure 8-3), a time or event programmable digital voltmeter of sufficient sensitivity and the SPC under test. + +#### d) Measurement procedure + +Using the circuit of Figure 8-3, a current ramp of sufficient amplitude to reach the $V_{(PT)}$ region is applied to the SPC. The voltage $V_{(PT)}$ is measured by programming the digital voltage recorder to measure the maximum voltage that occurs. + +#### e) Specified conditions + +- ambient or case temperature ( $T_a$ , $T_c$ ). + +### 8.3.5 Snap-back voltage $V_{(SB)}$ + +#### a) Purpose + +To measure the peak low-current voltage of a diode. This applies to punch-through or fold-back diodes. + +#### b) Circuit diagram + +Figure 8-3. + +#### c) Circuit description and requirements + +Main elements are a current ramp generator of sufficient current and duration (Figure 8-3), a time or event programmable digital voltmeter of sufficient sensitivity and the SPC under test. + +#### d) Measurement procedure + +Using the circuit of Figure 8-3, a current ramp of sufficient amplitude to reach the $V_{(SB)}$ region is applied to the SPC. The voltage $V_{(SB)}$ is measured by programming the digital voltage recorder to measure the minimum voltage that occurs after $V_{(PT)}$ . The current ramp speed should be selected to avoid possible transient effects, if too fast, or heating effects, if too slow. + +#### e) Specified conditions + +- ambient or case temperature ( $T_a$ , $T_c$ ). + +### 8.3.6 Forward biased PN junction voltage, $V_F$ + +#### a) Purpose + +To measure the forward voltage of a diode at a specified current. + +#### b) Circuit diagram + +Figure 8-1 or Figure 8-4. + +#### c) Circuit description and requirements + +Main elements are a current pulse generator of sufficient current and duration (Figure 8-1) or a defined surge impulse generator (Figure 8-4), a time or event programmable digital voltmeter of sufficient sensitivity and the SPC under test. + +#### d) *Measurement procedure* + +Using the circuit of Figure 8-1 or Figure 8-4, a current pulse or impulse of $I_{PP}$ is applied to the SPC, the forward voltage $V_F$ is measured after any transient effects have died out and before any pulse heating effects cause a change in the $V_F$ value. + +#### e) *Specified conditions* + +- ambient or case temperature ( $T_a$ , $T_c$ ); +- peak pulse current ( $I_{PP}$ ); +- pulse duration used if appropriate; +- surge impulse used if appropriate. + +### 8.3.7 Peak forward recovery voltage, $V_{FRM}$ + +#### a) *Purpose* + +To measure the peak forward recovery voltage of a diode at a specified rate of forward current rise ( $di_F/dt$ ). + +#### b) *Circuit diagram* + +Figure 8-1. + +#### c) *Circuit description and requirements* + +Main elements are a current pulse generator of sufficient current ( $I_F$ ) and specified rate of current rise ( $di_F/dt$ ) (Figure 8-1), a time or event programmable digital voltmeter of sufficient sensitivity and the SPC under test. + +#### d) *Measurement procedure* + +Using the circuit of Figure 8-1, a current pulse is applied to the SPC, the maximum forward voltage $V_{FRM}$ is measured after any transient effects have died out, see Figure 8-6. + +#### e) *Specified conditions* + +- ambient or case temperature ( $T_a$ , $T_c$ ); +- forward current ( $I_F$ ); +- rate of forward current rise ( $di_F/dt$ ). + +![Figure 8-6 shows two waveforms versus time (t in μs). The top graph shows the forward voltage (V) rising to a peak value V_FRM and then settling to a steady-state value V_F. The bottom graph shows the forward current (i) rising with a specified rate di_F/dt to a steady-state value I_F.](2aec26453a9ccef03f76f0a531a01a1a_img.jpg) + +The figure contains two vertically aligned graphs sharing a common horizontal time axis labeled $t$ ( $\mu\text{s}$ ). + +The top graph plots forward voltage $V$ on the vertical axis. The curve starts at the origin, rises sharply to a peak labeled $V_{FRM}$ , and then decays towards a steady-state value labeled $V_F$ . A vertical double-headed arrow indicates the magnitude of $V_F$ . + +The bottom graph plots forward current $i$ on the vertical axis. The curve starts at the origin and rises with a constant slope, indicated by a double-headed arrow and labeled $di_F/dt$ , until it reaches a steady-state value labeled $I_F$ . A vertical double-headed arrow indicates the magnitude of $I_F$ . + +Figure 8-6 shows two waveforms versus time (t in μs). The top graph shows the forward voltage (V) rising to a peak value V\_FRM and then settling to a steady-state value V\_F. The bottom graph shows the forward current (i) rising with a specified rate di\_F/dt to a steady-state value I\_F. + +K.129(18)\_F8-6 + +Figure 8-6 – Diode forward voltage and current waveforms versus time + +### 8.3.8 Total capacitance $C_{tot}$ + +#### a) Purpose + +To measure the capacitance of a diode at a specified direct current (DC) voltage ( $V_D$ ), AC voltage ( $V_a$ ) and frequency ( $f$ ). + +#### b) Circuit diagram + +Figure 8-5. + +#### c) Circuit description and requirements + +Main elements are a Kevin connection capacitance measurement meter, the Kelvin voltage ( $H_v, L_v$ ) and current ( $H_i, L_i$ ) leads and the SPC under test. + +#### d) Measurement procedure + +Set the capacitance meter for the specified DC bias voltage ( $V_D$ ), AC test voltage ( $V_a$ ) and frequency ( $f$ ). Measure the SPC capacitance. There may be a requirement to measure the capacitance at more than one value of DC bias voltage ( $V_D$ ). + +#### e) Specified conditions + +- ambient or case temperature ( $T_a, T_c$ ); +- DC bias voltage ( $V_D$ ); +- AC test voltage ( $V_a$ ); +- frequency ( $f$ ). + +## 8.4 Measuring methods for thermal characteristics + +### 8.4.1 Introduction + +The measurement of thermal resistance and transient thermal impedance is based on the use of a temperature-sensitive parameter of the semiconductor as an indicator of virtual junction temperature ( $T_j$ ). The forward voltage ( $V_F$ ) of a diode, at a small percentage of rated current, can be used as the temperature-sensitive parameter or the breakdown voltage ( $V_{BR}$ ). + +### 8.4.2 Transient thermal impedance $Z_{th(j-a)(t)}$ or $Z_{th(j-c)(t)}$ or $Z_{th(j-l)(t)}$ + +#### a) Purpose + +To measure the transient thermal impedance ( $Z_{th(j-a)(t)}$ or $Z_{th(j-c)(t)}$ or $Z_{th(j-l)(t)}$ ) of a SPC at a specified ambient ( $T_a$ ), case ( $T_c$ ), or lead ( $T_l$ ) temperature. + +#### b) Circuit diagram + +Figure 8-7. + +![Circuit diagram for transient thermal impedance test. It shows a generator (G) connected to a diode. The diode is connected to a reference current source (I_REF) and a voltmeter (V) in parallel. The voltmeter is connected to the SPC (Semiconductor Package) under test. The generator (G) is shown with a pulse waveform labeled I. The diagram is labeled K.129(18)_F8-7.](bf10cf36bba7b1d1f5ba30447da6905f_img.jpg) + +``` + +graph LR + G[Generator G] -- Pulse I --> D{Diode} + D --> Node1 + Node1 --> IREF((I_REF)) + Node1 --> V[Voltmeter V] + Node1 --> SPC[SPC under test] + IREF --> Rail + V --> Rail + SPC --> Rail + +``` + +The diagram shows a circuit for measuring transient thermal impedance. On the left, a generator (G) is connected to a diode. The diode's anode is connected to the generator's output, and its cathode is connected to a node. From this node, three parallel branches extend to the right: a reference current source labeled $I_{REF}$ , a voltmeter labeled V, and the semiconductor package (SPC) under test. All three branches rejoin at a common bottom rail. The generator (G) is shown with a pulse waveform labeled I. The diagram is labeled K.129(18)\_F8-7. + +Circuit diagram for transient thermal impedance test. It shows a generator (G) connected to a diode. The diode is connected to a reference current source (I\_REF) and a voltmeter (V) in parallel. The voltmeter is connected to the SPC (Semiconductor Package) under test. The generator (G) is shown with a pulse waveform labeled I. The diagram is labeled K.129(18)\_F8-7. + +**Figure 8-7 – Transient thermal impedance test circuit** + +#### c) Circuit description and requirements + +Main elements are a reference current source ( $I_{REF}$ ) for the temperature sensitive parameter, a high current pulsed source ( $I \gg I_{REF}$ ) for applying the power pulse to the SPC, a time or event programmable digital voltmeter of sufficient sensitivity and the SPC under test. + +#### d) *Measurement procedure* + +The $I_{REF}$ current flows continuously. The current pulse $I$ should be of sufficient amplitude that it causes a temperature rise of at least 50 K at the end of the pulse duration ( $t$ ). The temperature rise is calculated from the difference in the reference parameter immediately before and immediately after the pulse divided by the reference parameter temperature coefficient. The transient thermal impedance is calculated from the calculated temperature rise divided by the product of the pulsed current and the average voltage measured during the pulse duration. + +#### e) *Specified conditions* + +- ambient or case or lead temperature ( $T_a$ , $T_c$ , $T_l$ ); +- pulse duration ( $t$ ). + +### 8.4.3 Thermal resistance $R_{th(j-a)}$ or $R_{th(j-c)}$ or $R_{th(j-l)}$ + +The technique for thermal resistance ( $R_{th(j-a)}$ or $R_{th(j-c)}$ or $R_{th(j-l)}$ ) is the same as transient thermal impedance, see clause 8.4.2, except the pulse duration must be long enough for the temperature rise to have stabilised at a constant value. Typically, the pulse duration to achieve thermal equilibrium is in the region of 100 s. + +### 8.4.4 Temperature coefficient of breakdown voltage $V_{(BR)}$ , $\alpha V_{(BR)}$ + +#### a) *Purpose* + +To measure the temperature coefficient of breakdown voltage ( $\alpha V_{(BR)}$ ) of a diode at a specified current. This approach can also be used for determining the temperature coefficient of forward voltage ( $\alpha V_F$ ). + +#### b) *Circuit diagram* + +Figure 8-1. + +#### c) *Circuit description and requirements* + +Main elements are a current pulse generator of sufficient current and duration, a time or event programmable digital voltmeter of sufficient sensitivity and the SPC under test. The SPC is mounted in a temperatures control oven + +#### d) *Measurement procedure* + +Using the circuit of Figure 8-1, a current pulse of $I_{(BR)}$ is applied to the SPC, the voltage $V_{(BR)}$ is measured before any heating effects cause a change in the $V_{(BR)}$ value. This measurement is repeated at several temperatures within the specified operating temperature range. The temperature coefficient between successive temperatures is the change in $V_{(BR)}$ divided by the change in temperature. Often $\alpha_{V(BR)}$ is quoted as a %/K obtained by multiplying the calculated $V/K$ value by 100 and dividing by the average value of $V_{(BR)}$ between the two temperatures. + +#### e) *Specified conditions* + +- temperature range; +- breakdown current ( $I_{(BR)}$ ). + +## 8.5 Verification test methods for ratings (limiting values) + +### 8.5.1 Peak pulse current, $I_{PP}$ + +#### a) *Purpose* + +To verify the peak pulse current ( $I_{PP}$ ) of a diode at a specified ambient temperature ( $T_a$ ). + +#### b) *Circuit diagram* + +Figure 8-2 and Figure 8--4. + +#### c) *Circuit description and requirements* + +The Figure 8-2 circuit has a voltage pulse generator to apply the specified $V_{\text{RMW}}$ or $V_{\text{R}}$ to the SPC. A time or event programmable digital ammeter of sufficient sensitivity measures the $I_{\text{R}}$ value. The Figure 8-4 circuit applies a specified surge impulse of $I_{\text{PP}}$ to the SPC for a specified number of times and polarities. + +#### d) *Measurement procedure* + +Using the circuit of Figure 8-2, measure the selected SPC $I_{\text{R}}$ value, see clause 8.3.1. Using the circuit of Figure 8-4 apply the specified surge impulse of $I_{\text{PP}}$ to the SPC for the specified number of times and polarities. After the surge impulse testing is completed re-measure the selected SPC $I_{\text{R}}$ value. The final value of $I_{\text{R}}$ shall not have degraded to exceed the specified maximum limit $I_{\text{R}}$ value. + +#### e) *Specified conditions* + +- ambient or case temperature ( $T_{\text{a}}$ , $T_{\text{c}}$ ); +- peak pulse current ( $I_{\text{PP}}$ ); +- surge impulse waveshape; +- surge impulse repetitions and polarities; +- maximum data sheet value of $I_{\text{R}}$ . + +### 8.5.2 Maximum peak pulse power $P_{\text{PP}}$ + +This parameter is fictive in that it is the product of two values that do not necessarily occur at the same instant of time. The maximum peak pulse power value ( $P_{\text{PP}}$ ) is the product of the peak pulse current ( $I_{\text{PP}}$ ) and the maximum value of clamping voltage ( $V_{\text{C}}$ ). + +### 8.5.3 Power dissipation, $P_{\text{tot}}$ + +The maximum power dissipation at a specified ambient temperature is the quotient of the difference between the maximum junction temperature ( $T_{\text{JMAX}}$ ) and the specified ambient ( $T_{\text{a}}$ ) and the thermal resistance value ( $R_{\text{th(j-a)}}$ ). + +# 9 Mechanical requirements and identification + +## 9.1 Robustness of terminations + +If applicable, the user shall specify a suitable test from [b-IEC 60068-2-21]. + +## 9.2 Solderability + +Solder terminations shall meet the requirements of [b-IEC 60068-2-20]. + +## 9.3 Marking + +Legible and permanent marking shall be applied to the surge protective component, as necessary, to ensure that the user can determine the following information by inspection: + +- a) manufacturer; +- b) year of manufacture; +- c) component number or code. + +If requested and agreed, the customer's identification should be marked on each component. + +NOTE 1 – The necessary information can also be coded. + +NOTE 2 – When space is not sufficient for printing these data, it should be provided in the technical documentation after agreement between the manufacturer and purchaser. + +## **9.4 Documentation** + +Documents shall be provided to the user so that from the information in clause 9.3, the user can determine the following additional information: + +- a) appropriate component parameters as set out in this standard; +- b) component mounting requirements and processes; +- c) ordering information. + +The following information should be supplied by the user: + +- a) drawing giving all dimensions, finishes and termination details; +- b) type or model; +- c) quantity; +- d) quality assurance requirements. + +# Bibliography + +- [b-ITU-T K.11] Recommendation ITU-T K.11 (2009), *Principles of protection against overvoltages and over currents*. +- [b-ITU-T K.20] Recommendation ITU-T K.20 (2017), *Resistibility of telecommunication equipment installed in a telecommunication centre to overvoltages and overcurrents*. +- [b-ITU-T K.21] Recommendation ITU-T K.21 (2017), *Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents*. +- [b-ITU-T K.44] Recommendation ITU-T K.44 (2017), *Resistibility tests for telecommunication equipment exposed to overvoltages and overcurrents – Basic Recommendation*. +- [b-ITU-T K.45] Recommendation ITU-T K.45 (2017), *Resistibility of telecommunication equipment installed in the access and trunk networks to overvoltages and overcurrents*. +- [b-IEC IEV] IEC 60050, *International Electrotechnical Vocabulary (IEV)*. +- [b-IEC 60068-2-20] IEC 60068-2-20 (2008), *Environmental testing – Part 2-20: Tests – Test T: Test methods for solderability and resistance to soldering heat of devices with leads*. +- [b-IEC 60068-2-21] IEC 60068-2-21 (2008) *Environmental testing – Part 2-21: Tests – Test U: Robustness of terminations and integral mounting devices*. +- [b-IEC 60617] IEC 60617 (2012), *Graphical symbols for diagrams*. +- [b-IEC 60721-3-3] IEC 60721-3-3:1994+AMD1:1995+AMD2 (1996), *Classification of environmental conditions – Part 3-3: Classification of groups of environmental parameters and their severities – Stationary use at weather protected locations*. +- [b-IEC 60721-3-9] IEC 60721-3-9 (1993), *Classification of environmental conditions - Part 3: Classification of groups of environmental parameters and their severities – Section 9: Microclimates inside products*. +- [b-IEC 60747-1] IEC 60747-1:2006+AMD1 (2010), *Semiconductor devices – Part 1: General*. +- [b-IEC 60747-2] IEC 60747-2 (2016), *Semiconductor devices – Part 2: Discrete devices – Rectifier diodes*. +- [b-IEC 60747-3] IEC 60747-3 (2013), *Semiconductor devices – Part 3: Discrete devices: Signal, switching and regulator diodes*. +- [b-IEC 60749-1] IEC 60749-1 (2002), *Semiconductor devices – Mechanical and climatic test methods – Part 1: General*. +- [b-IEC 61000-5-5] IEC 61000-5-5 (1996), *Electromagnetic compatibility (EMC) – Part 5: Installation and mitigation guidelines – Section 5: Specification of protective devices for HEMP conducted disturbance. Basic EMC Publication*. +- [b-IEC 61643-321] IEC 61643-321 (2001), *Components for low-voltage surge protective devices – Part 321: Specifications for avalanche breakdown diode (ABD)*. + +- [b-IEC 62624] IEC 62624 (2009), *Test methods for measurement of electrical properties of carbon nanotubes.* +- [b-IEC TR 62240-1] IEC TR 62240-1 (2018), *Process management for avionics - Electronic components capability in operation – Part 1: Temperature uprating.* + + + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.132-201801-I_PDF-E/raw.md b/marked/K/T-REC-K.132-201801-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..bd5d9fa3da32523e3e3c5c303a3805bf05738da1 --- /dev/null +++ b/marked/K/T-REC-K.132-201801-I_PDF-E/raw.md @@ -0,0 +1,550 @@ + + +I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n + +# **ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +# **K.132** + +(01/2018) + +### SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Electromagnetic compatibility requirements of +electromagnetic disturbances from lighting +equipment located in telecommunication +facilities** + +Recommendation ITU-T K.132 + +**ITU-T** + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a blue globe with a red lightning bolt striking it. To the right of the globe, the text "International Telecommunication Union" is written in blue. + +ITU logo + +**International +Telecommunication +Union** + + + +# Recommendation ITU-T K.132 + +# Electromagnetic compatibility requirements of electromagnetic disturbances from lighting equipment located in telecommunication facilities + +## Summary + +Recommendation ITU-T K.132 specifies limits and measurement methods of electromagnetic disturbances from lighting equipment for installation in telecommunication facilities. The requirements in Recommendation ITU-T K.132 are based on CISPR 15 and CISPR 32 for continuous electromagnetic disturbances. Furthermore, Recommendation ITU-T K.132 specifies the limit of transient conducted current and measurement methods. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.132 | 2018-01-13 | 5 | 11.1002/1000/13455 | + +## Keywords + +Disturbance, lighting equipment, transient. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2018 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|-------------------|----------------------------------------------------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 3.1 | Terms defined elsewhere ..... | 1 | +| 3.2 | Terms defined in this Recommendation..... | 2 | +| 4 | Abbreviations and acronyms ..... | 2 | +| 5 | Conventions ..... | 2 | +| 6 | Limits..... | 2 | +| 6.1 | Limits for conducted disturbances at mains ports ..... | 3 | +| 6.2 | Limits for radiated disturbances ..... | 3 | +| 6.3 | Limits for transient currents at mains port ..... | 4 | +| 7 | Measurement methods ..... | 4 | +| 7.1 | Conducted disturbance at mains ports ..... | 4 | +| 7.2 | Radiated disturbances ..... | 4 | +| 7.3 | Transient currents at mains port ..... | 4 | +| Annex A | Transient current measurement method at a mains port..... | 5 | +| A.1 | General ..... | 5 | +| A.2 | Measurement system layout ..... | 5 | +| A.3 | Measurement instruments..... | 6 | +| A.4 | Test site..... | 7 | +| A.5 | Measurement procedure ..... | 7 | +| Appendix I | – The measurement example of radiated disturbance over 300 MHz from
lighting equipment..... | 9 | +| I.1 | Measurement method ..... | 9 | +| I.2 | Measurement results..... | 9 | +| Appendix II | An example of a malfunction caused by a transient disturbance on switching
on lighting equipment..... | 10 | +| II.1 | An example of actual condition..... | 10 | +| II.2 | An example of measurement in a laboratory..... | 11 | +| Bibliography..... | | 13 | + + + +# Recommendation ITU-T K.132 + +## Electromagnetic compatibility requirements of electromagnetic disturbances from lighting equipment located in telecommunication facilities + +# 1 Scope + +This Recommendation specifies limits and measurement methods for electromagnetic disturbances from lighting equipment for installation in telecommunication facilities. + +The electromagnetic disturbances specified in this Recommendation are continuous conducted and radiated disturbances emitted when lighting equipment is operating, and conducted transient disturbances generated when it is switched on and off. The frequency range of continuous conducted disturbances, from 9 kHz to 30 MHz, and continuous radiated disturbances, in the frequency range 30 MHz to 1 GHz, lie within the scope of this Recommendation. + +Additionally, this Recommendation specifies the limit of conducted transient disturbances to prevent malfunctions in telecommunication equipment that transmits signals below 30 MHz, such as the integrated service digital network (ISDN), asymmetric digital subscriber line (ADSL) and very high bit rate digital subscriber line (VDSL). + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T K.48] Recommendation ITU-T K.48 (2006), *EMC requirements for telecommunication equipment – Product family Recommendation*. + +[CISPR 15] CISPR 15:2015, *Limits and methods of measurement of radio disturbance characteristics of electrical lighting and similar equipment*. + +[CISPR 16-1-2] CISPR 16-1-2:2017, *Specification for radio disturbance and immunity measuring apparatus and methods – Part 1-2: Radio disturbance and immunity measuring apparatus – Coupling devices for conducted disturbance measurements*. + +[CISPR 32] CISPR 32:2015, *Electromagnetic compatibility of multimedia equipment – Emission requirements*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 conducted disturbance** [b-IEC 60050], 161-03-27: Electromagnetic disturbance for which the energy is transferred via one or more conductors. + +**3.1.2 electromagnetic disturbance** [b-IEC 60050], 161-01-05: Any electromagnetic phenomenon which can degrade the performance of a device, equipment or system, or adversely affect living or inert matter. + +**3.1.3 port** [b-IEC 60050], 161-01-27: Particular interface of an equipment which couples this equipment with the external electromagnetic environment and through which the equipment is influenced by this environment. + +**3.1.4 radiated disturbance** [b-IEC 60050], 161-03-28: Electromagnetic disturbance for which the energy is transferred through space in the form of electromagnetic waves. + +**3.1.5 transient** [b-IEC 60050], 161-02-01: Pertaining to or designating a phenomenon or a quantity which varies between two consecutive steady states during a time interval short compared with the timescale of interest. + +## **3.2 Terms defined in this Recommendation** + +This Recommendation defines the following term: + +**3.2.1 telecommunication facility:** A facility that mainly houses telecommunication equipment, such as telecommunication equipment rooms or remotely located telecommunication sites. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|--------------------------------------------| +| ADSL | Asymmetric Digital Subscriber Line | +| CDN | Coupling and Decoupling Network | +| CRC | Cyclic Redundancy Check | +| EUT | Equipment Under Test | +| ISDN | Integrated Service Digital Network | +| LED | Light-Emitting Diode | +| OATS | Open-Air Test Site | +| PC | Personal Computer | +| RBW | Resolution Bandwidth | +| SAC | Semi-Anechoic Chamber | +| VDSL | Very high bit rate Digital Subscriber Line | + +# **5 Conventions** + +None. + +# **6 Limits** + +The limits of disturbance from telecommunication equipment are specified in [ITU-T K.48] and [CISPR 32]. In order to harmonize the levels of disturbances from telecommunication equipment and lighting equipment that are installed in a telecommunication equipment room, the disturbance from lighting equipment should be the same or lower than that from telecommunication equipment. + +In this Recommendation, the limits of continuous conducted and radiated disturbances in the frequency range 9 kHz to 300 MHz from lighting equipment are specified with reference to [CISPR 15]. The limits of radiated continuous disturbance above 300 MHz to 1 GHz are specified with reference to [CISPR 32]. The limit is set also between 300 MHz and 1 GHz, since radiated disturbance in this frequency range is observed in commercially available light sources, as shown in Appendix I. Moreover, a limit for transient disturbance is required in this Recommendation, since malfunctions in transmission systems have been reported caused by transient disturbance generated + +by lighting equipment switching operations in telecommunication equipment rooms, as shown in Appendix II. + +## 6.1 Limits for conducted disturbances at mains ports + +Disturbances measured by a quasi-peak and average detector at the mains ports shall not be greater than the values in Table 1. + +**Table 1 – Test methods and limits for conducted disturbance voltage at main ports +(from [CISPR 15])** + +| Frequency range | Test methods | Limits (dB $\mu$ V) | | +|--------------------|--------------------|---------------------|----------| +| | Reference standard | Quasi-peak | Average | +| 9 kHz to 50 kHz | [CISPR 15] | 110 | – | +| 50 kHz to 150 kHz | | 90 to 80 | – | +| 150 kHz to 0.5 MHz | | 66 to 56 | 56 to 46 | +| 0.5 MHz to 5.0 MHz | | 56 | 46 | +| 5 MHz to 30 MHz | | 60 | 50 | + +NOTE 1 – 1 $\mu$ V is taken to be 0 dB $\mu$ V. + +NOTE 2 – If the quasi-peak value of measurement is less than the limit specified for average value detection, the equipment shall be deemed to meet both limits and there is no need to measure the average value. + +NOTE 3 – The lower limit shall apply at transition frequency. + +NOTE 4 – The limit shall decrease linearly with the logarithm of frequency. + +NOTE 5 – For electrode-less lamps and luminaires, the limit in the frequency range 2.51 to 3.00 MHz is not applied in this Recommendation. + +## 6.2 Limits for radiated disturbances + +The limit values of radiated disturbances shall not be greater than the values at the specified distance given in Table 2. + +**Table 2 – Test methods and limits for radiated disturbances (10 m)** + +| Frequency range (MHz) | Test methods | | Quasi-peak limit (dB $\mu$ V/m) | +|-----------------------|------------------------------------------------------------------------|--------------------|---------------------------------| +| | Measurement facility | Reference standard | | +| 30-230 | Semi-anechoic chamber (SAC) or open-air test site (OATS) 10 m distance | [CISPR 15] | 30 | +| 230-300 | | | 37 | +| 300-1000 | | [CISPR 32] | 37 | + +NOTE 1 – 1 $\mu$ V/m is taken to be 0 dB $\mu$ V/m. + +NOTE 2 – The lower limit shall apply at the transition frequency. + +NOTE 3 – Add 10 dB to the limit when measurement distance is 3 m. Subtract 10 dB from the limit when the measurement distance is 30 m. + +NOTE 4 –The coupling and decoupling network (CDN) measurement method described in Annex B of [CISPR 15] is not applied in this Recommendation, because the measurement method has not yet been established. + +## 6.3 Limits for transient currents at mains port + +The limit for transient currents that arise at a mains port when a piece of lighting equipment is turned on and off is shown in Table 3. + +**Table 3 – Test method and limit for transient current** + +| Test methods | Limit | +|--------------|--------------------| +| Annex A | 5 A p-p | + +# 7 Measurement methods + +This clause describes the measurement methods for electromagnetic disturbances emitted from lighting equipment. + +## 7.1 Conducted disturbance at mains ports + +- 1) Measurement arrangement and procedures + +Measurement arrangement and procedure shall comply with [CISPR 15]. + +- 2) Components of lighting equipment and operating conditions + +The equipment under test (EUT) for the emission test shall consist of all components based on the manufacturer's specification for the equipment. If the lighting equipment is of the twin tube type, measurement shall be carried out with the two tubes attached. + +Operating conditions of the lighting equipment shall comply with clause 6 of [CISPR 15]. + +- 3) Measurement instruments and test site + +Measurement instruments and test site shall comply with [CISPR 32]. + +## 7.2 Radiated disturbances + +- 1) Measurement arrangement and procedures + +Measurement arrangement and procedure shall comply with [CISPR 32]. General measurement arrangements and test procedures are given in [CISPR 15]. + +- 2) Components of lighting equipment and operating conditions + +The EUT for the emission test shall consist of all components based on the manufacturer's specification for the equipment. If the lighting equipment is of the twin tube type, measurement shall be carried out with the two tubes attached. Operating conditions shall comply with clause 6 of [CISPR 15]. + +- 3) Measurement instruments and test site + +Measurement instruments and test site shall comply with [CISPR 32]. + +## 7.3 Transient currents at mains port + +- 1) Measurement arrangement and procedures + +Measurement arrangement and procedure shall comply with Annex A. + +- 2) Components of lighting equipment and operating conditions + +Components of lighting equipment shall be based on normal conditions provided by the manufacturer. If the lighting equipment is of the twin tube type, measurement shall be carried out with the two tubes attached. + +Operating conditions shall comply with clause 6 of [CISPR 15]. + +- 3) Measurement instruments and locations + +Measurement instruments and locations shall comply with Annex A. + +# Annex A + +## Transient current measurement method at a mains port + +(This annex forms an integral part of this Recommendation.) + +### A.1 General + +This clause specifies the measurement method for transient currents at mains ports that arise when lighting equipment is switched on or off in an environment in which the lighting equipment is connected to the mains network and the supply is switched electronically or mechanically. + +### A.2 Measurement system layout + +The measurement system is shown in Figure A.1. One of the phase lines of the power supply to the EUT is clamped by a current probe. The transient current on the phase line is measured when the switch is turned on and off using an oscilloscope. In addition, a differential voltage probe is connected between the lines of the power supply to the EUT. The power switch is turned on or off using a switch that can operate at a specific phase of the power supply voltage. A circuit that simulates the power impedance is inserted between the EUT and the programmable switch. The length of the line between the EUT and the power impedance simulation circuit shall be 0.8 m. The current probe should be set to the phase line of the power supply to the EUT at a distance of 0.1 m from the EUT. The mains power outlet at the measuring site can be used, but a correction capacitor shall be inserted between the power line and the mains port of the switch. The external trigger port of the oscilloscope shall be connected to the synchronization signal output port of the switch. If the programmable switch does not have a trigger signal output, the output of the differential voltage probe can be used as a triggering signal. + +The EUT, the programmable switch, the correction capacity and the power impedance simulation circuit shall be placed on a table of an insulating material at a height of 0.4 m above the reference ground plane. The reference ground plane shall be made of metal extending more than 0.5 m from the edge of the EUT and 2 m × 2 m in size or larger. If the EUT has an earthing port, it shall be connected to the reference ground plane with as short a conducting wire as possible. An artificial mains network, which is used to measure the continuous conducted disturbances, and the load except for the EUT shall not be connected to the transient current measurement system. + +![Figure A.1 – Transient current measurement system. The diagram shows a series of components connected in a circuit: a Power Supply (PS) connected to a Capacitor (C), which is connected to a Programmable Switch (SW) with a Voltage detector, which is connected to an Artificial Network (AN). A Differential Voltage Probe (DVP) is connected across the AN. A Current Probe (CP) is connected to the AN. The AN is connected to the Equipment Under Test (EUT). The EUT is connected to a Ground plane. The PS is connected to the Ground plane. The SW is connected to the Ground plane. The AN is connected to the Ground plane. The EUT is connected to the Ground plane. The DVP is connected to the Ground plane. The CP is connected to the Ground plane. The OS (Oscilloscope) is connected to the DVP and the CP. The SYN (Signal synchronized with switching) is connected to the OS. The IS (Insulating support) is shown below the components, with dimensions 0.1 m, 0.8 m, and 0.4 m. The Ground plane is shown at the bottom.](d4af765160d04ecef538e5066006dc77_img.jpg) + +EUT: Equipment under test                      CO: Current probe + OS: Oscilloscope                                      DVP: Differential voltage probe + SW: Programmable switch                      SYN: Signal synchronized with switching + C: Capacitor                                            PS: Power supply + AN: Artificial network                            IS: Insulating support + +K.132(18)\_FA.1 + +Figure A.1 – Transient current measurement system. The diagram shows a series of components connected in a circuit: a Power Supply (PS) connected to a Capacitor (C), which is connected to a Programmable Switch (SW) with a Voltage detector, which is connected to an Artificial Network (AN). A Differential Voltage Probe (DVP) is connected across the AN. A Current Probe (CP) is connected to the AN. The AN is connected to the Equipment Under Test (EUT). The EUT is connected to a Ground plane. The PS is connected to the Ground plane. The SW is connected to the Ground plane. The AN is connected to the Ground plane. The EUT is connected to the Ground plane. The DVP is connected to the Ground plane. The CP is connected to the Ground plane. The OS (Oscilloscope) is connected to the DVP and the CP. The SYN (Signal synchronized with switching) is connected to the OS. The IS (Insulating support) is shown below the components, with dimensions 0.1 m, 0.8 m, and 0.4 m. The Ground plane is shown at the bottom. + +**Figure A.1 – Transient current measurement system** + +### A.3 Measurement instruments + +The basic configuration of the system for transient current measurement is shown in Figure A.1. Measurement instruments used for the system are specified in clauses A.3.1 to A.3.6. + +#### A.3.1 Oscilloscope + +An oscilloscope that can take more than 250 million samples per second and can start sampling with an external trigger shall be used. There shall be at least two input channels for waveform monitoring and another channel for trigger input. A peak detection mode may be selected in order to record the true peak value. + +#### A.3.2 Programmable switch (electronic switch for the on/off control of the power supply) + +An electronic switch that can detect the phase of the power supply voltage and can switch the power on or off when the phase is $90^\circ$ or $270^\circ$ shall be used. An electronic switch shall be able to output a signal to the external trigger input of an oscilloscope at an instant when the power is switched on or off in order to measure the current waveform in synchronization with the power switching operation. However, if a programmable switch cannot be acquired, the peak level of the transient current may be obtained by turning a hand-operated switch on and off 30 times. + +#### A.3.3 Current probe + +The current probe for measurement shall conform to [CISPR 16-1-2], and the measurement frequency shall cover the range 30 Hz to 100 MHz, and shall measure a peak current of around 30 A. + +#### A.3.4 Differential voltage probe + +A differential voltage probe shall be able to measure the supply voltage of the mains. This probe is mainly used to verify that the timing of switching is at the maximum and minimum of the power supply voltage. + +If the programmable switch does not have a function to output the trigger signal, the probe can be used as trigger detection. + +#### A.3.5 Compensation capacitor + +In this test, the commercial mains are also used to supply power to the lighting equipment. However, the impedance of commercial mains changes depending on the measurement site. A capacitor (with a capacitance of 10 $\mu\text{F}$ ) shall be inserted between the mains port of the programmable switch and the power cable to eliminate the effect of the mains' impedance at the measurement site. The capacitors may be connected in parallel to obtain the necessary capacitance and a withstand voltage of 440 V or higher is desirable. + +#### A.3.6 Power impedance simulation circuit + +The power impedance simulation circuit shall have the impedance characteristics shown in Figure A.2 in the frequency range 1 kHz to 10 MHz. The impedance of the circuit shall be measured at the port of the EUT when the port on the programmable switch side is shorted. + +The allowable deviation of the impedance shall be $\pm 20\%$ , and that of the impedance phase angle $\pm 10^\circ$ . + +![Figure A.2: Impedance characteristics of a power impedance simulation circuit. It includes a circuit diagram, a component value table, an impedance formula, and a graph of magnitude and phase angle vs. frequency.](8791f79b259a7463279c1aeb14c31580_img.jpg) + +The figure illustrates the impedance characteristics of a power impedance simulation circuit. It consists of a circuit diagram, a table of component values, an impedance formula, and a graph of magnitude and phase angle versus frequency. + +**Circuit Diagram:** The diagram shows an equivalent circuit with three components: R1, R2, and R3. R1 and R2 are connected in parallel, and this combination is connected in series with R3. The input terminals are labeled 'Equivalent circuit'. + +**Component Values:** + +| R1 [ $\Omega$ ] | R2 [ $\Omega$ ] | L1 [ $\mu\text{H}$ ] | +|-----------------|-----------------|----------------------| +| 85 | 0.5 | 10 | + +**Impedance Formula:** + +$$Z = \frac{R1 (R2 + j\omega L1)}{R1 + R2 + j\omega L1}$$ + +**Graph:** The graph plots Magnitude [ $\Omega$ ] on the left y-axis (0 to 100) and Phase angle [ $^\circ$ ] on the right y-axis (0 to 90) against Frequency [MHz] on a logarithmic x-axis (0.001 to 10). The 'Magnitude' curve (solid line) starts at approximately 10 $\Omega$ at 0.001 MHz, peaks at about 80 $\Omega$ at 0.1 MHz, and then decreases to about 10 $\Omega$ at 10 MHz. The 'Phase angle' curve (dashed line) starts at 0 $^\circ$ at 0.001 MHz, rises to about 80 $^\circ$ at 0.1 MHz, and then decreases to about 10 $^\circ$ at 10 MHz. + +Figure A.2: Impedance characteristics of a power impedance simulation circuit. It includes a circuit diagram, a component value table, an impedance formula, and a graph of magnitude and phase angle vs. frequency. + +Figure A.2 – Impedance characteristics of a power impedance simulation circuit + +## A.4 Test site + +A shielded room shall be used for the measurement of transient currents so that transient currents from the EUT can be isolated from ambient noise. The ambient noise measured at the site while the power switch is off (i.e., when no disturbances are emitted by the EUT) shall be small enough not to influence the measurement. + +## A.5 Measurement procedure + +The transient voltage shall be measured at both lines of power supply to the EUT. It is necessary to measure transient currents of each of the two power wires at the time of switching on and switching off when the phase of the mains voltage is $90^\circ$ and $270^\circ$ as shown in Figure A.3. In other words, transient currents shall be measured under a total of eight conditions. The timing of the switch operation shall be verified by measuring the waveform of the mains with the differential voltage probe. + +The peak levels of the transient current can be observed several microseconds or several seconds after the switching on or off of the power. An appropriate time span or triggering delay time shall be determined by checking the transient current waveforms so that the peak value of the current shall be overlooked. The recording length of the oscilloscope shall be 50 thousand samples or greater. + +![A graph showing a sinusoidal voltage waveform over time. The y-axis is labeled 'Voltage [V]' and ranges from -150 to 150. The bottom x-axis is labeled 'Time [ms]' and ranges from -5 to 30. The top x-axis is labeled 'Phase [degree]' and ranges from -90 to 540. The waveform starts at -150 V at -5 ms, crosses zero at 0 ms, reaches a peak of approximately 140 V at 5 ms, crosses zero at 10 ms, reaches a trough of approximately -140 V at 15 ms, crosses zero at 20 ms, reaches a peak of approximately 140 V at 25 ms, and crosses zero at 30 ms. A vertical dashed line at 5 ms indicates the timing at which the programmable switch turns the power on or off. An arrow points from the text 'Voltage waveform of commercial power supply in the case of 100 V/50 Hz' to the peak at 5 ms. Another arrow points from the text 'The timing at which the programmable switch turns the power on or off' to the vertical dashed line at 5 ms.](0b8b087a7baa471015d3ffeaa43d9a6c_img.jpg) + +Voltage waveform of commercial power supply +in the case of 100 V/50 Hz + +Phase [degree] + +Voltage [V] + +Time [ms] + +The timing at which the programmable switch turns the power on or off + +K.132(18)\_FA.3 + +A graph showing a sinusoidal voltage waveform over time. The y-axis is labeled 'Voltage [V]' and ranges from -150 to 150. The bottom x-axis is labeled 'Time [ms]' and ranges from -5 to 30. The top x-axis is labeled 'Phase [degree]' and ranges from -90 to 540. The waveform starts at -150 V at -5 ms, crosses zero at 0 ms, reaches a peak of approximately 140 V at 5 ms, crosses zero at 10 ms, reaches a trough of approximately -140 V at 15 ms, crosses zero at 20 ms, reaches a peak of approximately 140 V at 25 ms, and crosses zero at 30 ms. A vertical dashed line at 5 ms indicates the timing at which the programmable switch turns the power on or off. An arrow points from the text 'Voltage waveform of commercial power supply in the case of 100 V/50 Hz' to the peak at 5 ms. Another arrow points from the text 'The timing at which the programmable switch turns the power on or off' to the vertical dashed line at 5 ms. + +**Figure A.3 – Example of a voltage waveform** + +# Appendix I + +## The measurement example of radiated disturbance over 300 MHz from lighting equipment + +(This appendix does not form an integral part of this Recommendation.) + +This appendix provides an example of measurement of a radiated disturbance from lighting equipment with a frequency over 300 MHz. + +### I.1 Measurement method + +Since [CISPR 15] specifies the measurement method for radiated disturbances below 300 MHz from the lighting equipment, the radiated disturbance is measured with reference to [CISPR 32] [test distance: 10 m; detection: quasi peak; resolution bandwidth (RBW): 120 kHz]. In this measurement, the EUT (power source: single phase AC 100 V, power consumption: 7 W) was selected from commercially available light-emitting diode (LED) sources. A biconical antenna was used for measurement in the frequency range 30 MHz to 300 MHz and log-periodic antenna was used for frequencies over 300 MHz. + +### I.2 Measurement results + +Figure I.1 shows radiated disturbance measurement results, in which the red line represents the vertically polarized wave and the blue line represents the horizontally polarized wave. The result for the vertically polarized wave exceeds the quasi-peak limit in the frequency range lower than 300 MHz. Although radiated disturbance is higher, the limit was observed even at a frequencies higher than 300 MHz; no limit is currently specified in [CISPR 15]. Therefore, radiated disturbances in the frequency range 300 MHz to 1 GHz from lighting equipment located in a telecommunication equipment room is specified in this Recommendation. + +![Figure I.1: Measured continuous radiated disturbance using a light-emitting diode source as an example. The graph shows Electric field strength (dBμV/m) on the Y-axis (0 to 60) versus Frequency (MHz) on the X-axis (10.00 to 1000.00). The red line represents the Vertically polarized wave, and the blue line represents the Horizontally polarized wave. The vertically polarized wave shows higher field strength, peaking around 55 dBμV/m at 100 MHz, while the horizontally polarized wave peaks around 35 dBμV/m at 100 MHz.](4a8166688ed7276efb173f550ba47eb4_img.jpg) + +The figure is a line graph showing the measured continuous radiated disturbance from a light-emitting diode (LED) source. The Y-axis represents the Electric field strength in dBμV/m, ranging from 0 to 60. The X-axis represents the Frequency in MHz, ranging from 10.00 to 1000.00 on a logarithmic scale. Two data series are plotted: a red line for the vertically polarized wave and a blue line for the horizontally polarized wave. The red line shows higher field strength, with peaks around 55 dBμV/m at 100 MHz and 500 MHz. The blue line shows lower field strength, with peaks around 35 dBμV/m at 100 MHz and 300 MHz. The graph is labeled 'K.132(18)\_FI.1' in the bottom right corner. + +Figure I.1: Measured continuous radiated disturbance using a light-emitting diode source as an example. The graph shows Electric field strength (dBμV/m) on the Y-axis (0 to 60) versus Frequency (MHz) on the X-axis (10.00 to 1000.00). The red line represents the Vertically polarized wave, and the blue line represents the Horizontally polarized wave. The vertically polarized wave shows higher field strength, peaking around 55 dBμV/m at 100 MHz, while the horizontally polarized wave peaks around 35 dBμV/m at 100 MHz. + +Figure I.1 – Measured continuous radiated disturbance using a light-emitting diode source as an example + +# Appendix II + +## An example of a malfunction caused by a transient disturbance on switching on lighting equipment + +### II.1 An example of actual condition + +When a fluorescent lamp was turned on at an office in which an ADSL communication environment had been installed, a session time-out of the telecommunication system occurred. + +Figure II.1 shows the connection configuration of the communication system at the office. Some personal computers (PCs) are connected to an ADSL modem through router and hub. + +Figure II.2 illustrates the unsymmetrical voltages of the communication line and the power line of the ADSL modem measured with an oscilloscope when a fluorescent lamp is turned on. The disturbances in the communication line and the power line of the ADSL modem appear at the time of switching on the fluorescent lamp. The unsymmetrical voltage when the fluorescent lamp of the glow starter type was turned on was larger than that of other types and was about 10 Vp-p on the communication line, about 20 Vp-p on the power line. The ping test to head office system from the PC of the office connected to the ADSL was not confirmed, and session time-out occurred. + +![Figure II.1: Connection architecture of the office communication system. A block diagram showing the interconnection of a terminal board, ADSL modem, router, hub, and multiple PCs, along with power supply and fluorescent lamps.](41a438d7e4adc17c3a4005e7c9500091_img.jpg) + +``` +graph LR + TB[Terminal board] -- Communication line --- ADSL[ADSL modem] + TB -- Power line --- PS[Power supply AC100V] + ADSL -- Communication line Ethernet --- R[Router] + R --- H[HUB] + H --- PC1[PC] + H --- PC2[PC] + H --- PC3[...] + H --- PC4[PC] + PS --- FL1[Fluorescent lamp] + PS --- FL2[Fluorescent lamp] + PS --- FL3[Fluorescent lamp] + PS --- FL4[Fluorescent lamp] + FL1 --- ADSL + FL2 --- R + FL3 --- PS + FL4 --- PS +``` + +The diagram illustrates the office communication system architecture. A 'Terminal board' is connected to a 'Communication line' and a 'Power line'. The 'Communication line' connects to an 'ADSL modem', which is connected to a 'Router' via a 'Communication line (Ethernet)'. The 'Router' is connected to a 'HUB', which is connected to multiple 'PC' units. The 'Power line' connects to a 'Power supply (AC100V)', which is connected to four 'Fluorescent lamp' units. The diagram is labeled K.132(18)\_FII.1. + +Figure II.1: Connection architecture of the office communication system. A block diagram showing the interconnection of a terminal board, ADSL modem, router, hub, and multiple PCs, along with power supply and fluorescent lamps. + +**Figure II.1 – Connection architecture of the office communication system** + +![Figure II.2: Measurement result of ADSL modem at the office. Oscilloscope traces showing transient disturbances on the communication line and power line.](0bd23f00e0632855cfef9274f1ab93d8_img.jpg) + +The figure displays two oscilloscope traces. The top trace, labeled 'Communication line', shows a transient disturbance with a peak-to-peak voltage labeled as $20\text{V}_{\text{p-p}}$ . The bottom trace, labeled 'Power line', shows a transient disturbance with a peak-to-peak voltage labeled as $10\text{V}_{\text{p-p}}$ . The time scale is indicated as [2 μs/div]. The figure is labeled K.132(18)\_FII.2. + +Figure II.2: Measurement result of ADSL modem at the office. Oscilloscope traces showing transient disturbances on the communication line and power line. + +**Figure II.2 – Measurement result of ADSL modem at the office** + +### II.2 An example of measurement in a laboratory + +An experimental configuration using the VDSL system and an inverter-type fluorescent lamp in the laboratory is shown in Figure II.3. The power line of the lighting equipment runs side by side with the communication line of the VDSL system for approximately 10 m. + +Figure II.4 depicts a differential mode voltage on the communication line and a common mode current on the power line of the fluorescent lamp when it was turned on. The observed conducted disturbance was about $28\text{ V}_{\text{p-p}}$ on the communication line and about $9\text{ A}_{\text{p-p}}$ in the power line of the fluorescent lamp. A cyclic redundancy check (CRC) error was observed at the timing of turning on the fluorescent lamp by a line monitor function of the VDSL system with the PC. + +![Block diagram of the experiment system showing a VDSL system connected to a PC and a Modem, with a fluorescent lamp and power line running alongside the communication line. Measurement probes are connected to an Oscilloscope.](8307f6b04df072c9332f9987e034272c_img.jpg) + +The diagram illustrates the experimental setup. A vertical loop represents the 'Power line' and 'Communication line', with a height of 4 m and a width of 2 m. At the top of the loop, a 'Fluorescent lamp' is connected. At the bottom, a 'Modem' is connected to the communication line. The Modem is connected to a 'VDSL' unit, which is in turn connected to a 'PC'. The PC is connected to a 'Switch', which is connected to an 'Oscilloscope'. The Oscilloscope is also connected to a 'Trans.' (Transformer) unit. A 'Differential voltage probe' is connected to the communication line, and a 'Current probe' is connected to the power line. Both probes are connected to the Oscilloscope. A 'Power supply (AC100V)' is connected to the bottom of the loop. The diagram is labeled 'K.132(18)\_FII.3' in the bottom right corner. + +Block diagram of the experiment system showing a VDSL system connected to a PC and a Modem, with a fluorescent lamp and power line running alongside the communication line. Measurement probes are connected to an Oscilloscope. + +Figure II.3 – Experiment system + +![Two stacked plots showing Voltage [V] and Current [A] over Time [μs]. The top plot shows a voltage spike reaching approximately 15 V at 0 μs, followed by a noisy signal around 0 V. The bottom plot shows a current spike reaching approximately 5 A at 0 μs, followed by a noisy signal around 0 A. Both plots have a time axis from 0 to 10 μs.](b53846f262c6904a1b45abef2e95fbd8_img.jpg) + +The figure consists of two vertically stacked plots sharing a common time axis. The top plot shows Voltage [V] on the y-axis, ranging from -20 to 20, with major ticks at -20, -10, 0, 10, and 20. The bottom plot shows Current [A] on the y-axis, ranging from -10 to 10, with major ticks at -10, 0, 5, and 10. Both plots have a time axis labeled 'Time [μs]' with major ticks at 0, 5, and 10. The top plot shows a sharp positive spike reaching about 15 V at 0 μs, followed by a noisy signal fluctuating around 0 V. The bottom plot shows a sharp negative spike reaching about -5 A at 0 μs, followed by a noisy signal fluctuating around 0 A. A small label 'K.132(18)\_FII.4' is visible in the bottom right corner of the figure area. + +Two stacked plots showing Voltage [V] and Current [A] over Time [μs]. The top plot shows a voltage spike reaching approximately 15 V at 0 μs, followed by a noisy signal around 0 V. The bottom plot shows a current spike reaching approximately 5 A at 0 μs, followed by a noisy signal around 0 A. Both plots have a time axis from 0 to 10 μs. + +**Figure II.4 - Experimental result** + +# Bibliography + +[b-IEC 60050] IEC 60050, *International Electrotechnical Vocabulary*. + + + + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.133-201801-I_PDF-E/raw.md b/marked/K/T-REC-K.133-201801-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..674d08fc6795cc0ab7c567dabfa89b2b58145641 --- /dev/null +++ b/marked/K/T-REC-K.133-201801-I_PDF-E/raw.md @@ -0,0 +1,478 @@ + + +International Telecommunication Union + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.133** + +(01/2018) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Electromagnetic environment of body-worn +equipment in the 2.4 GHz and 13.56 MHz +industrial, scientific and medical band** + +Recommendation ITU-T K.133 + +ITU-T + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a red lightning bolt striking it, symbolizing telecommunications. To the right of the globe, the text "International Telecommunication Union" is written in blue, with the acronym "ITU" in a larger, bold blue font. + +ITU logo + +International +Telecommunication +Union + + + +# Recommendation ITU-T K.133 + +# Electromagnetic environment of body-worn equipment in the 2.4 GHz and 13.56 MHz industrial, scientific and medical band + +## Summary + +Recommendation ITU-T K.133 specifies electromagnetic characterization of the radiation and conduction environment for body-worn electronic devices. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.133 | 2018-01-13 | 5 | 11.1002/1000/13456 | + +## Keywords + +Body-worn equipment, electromagnetic environment, EM environment, body-worn device. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2018 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|-----|----------------------------------------------------------------------------------------------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 3.1 | Terms defined elsewhere ..... | 1 | +| 3.2 | Terms defined in this Recommendation..... | 1 | +| 4 | Abbreviations and acronyms ..... | 2 | +| 5 | Conventions ..... | 2 | +| 6 | Description of the body-worn device environment ..... | 2 | +| 6.1 | Typical configuration of the body-worn device environment..... | 2 | +| 6.2 | Powering and ports ..... | 3 | +| 6.3 | Mobility ..... | 4 | +| 6.4 | Possibility of interference..... | 4 | +| 7 | Typical phenomena in the electromagnetic environment of body-worn equipment .... | 4 | +| 8 | Disturbance characteristics and levels in the 2.4GHz and 13.56MHz bands ..... | 4 | +| 8.1 | Attributes of environment..... | 4 | +| 8.2 | Specification of disturbance characteristics and levels ..... | 5 | +| 9 | Interference management..... | 8 | +| | Appendix I – Study roadmap of the electromagnetic environment and electromagnetic compatibility issues of body-worn devices and Bluetooth v4 ..... | 9 | +| I.1 | Bluetooth v4 and the body-worn device electromagnetic environment..... | 9 | +| I.2 | Cases of electromagnetic compatibility failure in body-worn devices ..... | 9 | +| I.3 | Proposed procedure for the study of electromagnetic compatibility of body-worn devices..... | 9 | +| | Bibliography..... | 10 | + +# **Introduction** + +In recent years, many body-worn communication devices, such as those for medical use, smart watches and smart bracelets, have been produced and are widely used by the public. Most of them have a wireless fidelity (Wi-Fi) or Bluetooth module that uses the 2.4 GHz industrial, scientific and medical (ISM) band for communication or implement near field communication technology in the 13.56 MHz ISM band. This Recommendation is applicable to the environment in which body-worn equipment operates. + +## Recommendation ITU-T K.133 + +## Electromagnetic environment of body-worn equipment in the 2.4 GHz and 13.56 MHz industrial, scientific and medical band + +# 1 Scope + +This Recommendation specifies electromagnetic characterization of the radiation and conduction environment for body-worn electronic devices. Body-worn equipment includes that for electronic glasses, electronic bracelets, smartphone-supported watches and health supervision. + +This Recommendation aims to provide an effective and exercisable method to improve understanding of the electromagnetic (EM) environment of body-worn devices. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.34] Recommendation ITU-T K.34 (2003), *Classification of electromagnetic environmental conditions for telecommunication equipment – Basic EMC Recommendation*. +- [ITU-T K.79] Recommendation ITU-T K.79 (2015), *Electromagnetic characterization of the radiated environment in the 2.4 GHz ISM band*. +- [IEC TR 61000-2-5] IEC TR 61000-2-5:2017, *Electromagnetic compatibility (EMC) – Part 2-5: Environment – Description and classification of electromagnetic environments*. +- [ISO/IEC 18000-3] ISO/IEC 18000-3:2010, *Information technology – Radio frequency identification for item management – Part 3: Parameters for air interface communications at 13.56 MHz*. +- [ISO/IEC 18000-4] ISO/IEC 18000-4:2015, *Information technology – Radio frequency identification for item management – Part 4: Parameters for air interface communications at 2.45 GHz*. + +# 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following term defined elsewhere: + +**3.1.1 body-worn device** [b-ITU-T K.91]: A portable device containing a wireless transmitter or transceiver which may be located close to a person's torso except the head during its intended use or operation of its radio functions (e.g., on a belt clip, holster, pouch, or on a lanyard when worn as necklace). + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 electronic glasses equipment:** A type of body-worn device that is similar to glasses in shape and that has an information record module, as well as a signal-processing unit, incorporated within it. + +**3.2.2 electronic bracelet equipment:** A type of body-worn device that is similar to a bracelet in shape and that has an information record module, as well as a signal-processing unit, incorporated within it. + +**3.2.3 smart watch:** A type of body-worn device that is similar in shape to a watch and that has an information record module, as well as a signal-processing unit, incorporated within it. + +**3.2.4 wireless body area communication (WBAN):** A short-range communication technique within, on and in the immediate proximity of a human body. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|----------|-------------------------------------------| +| AC | Alternating Current | +| AM | Amplitude Modulation | +| DC | Direct Current | +| EM | Electromagnetic | +| EMC | Electromagnetic Compatibility | +| ERP | Effective Radiated Power | +| ESD | Electrostatic Discharge | +| HIPERLAN | High Performance Radio Local Area Network | +| ISM | Industrial, Scientific and Medical | +| LAN | Local Area Network | +| PLT | Power Line Telecommunication | +| RF | Radio Frequency | +| RFID | Radio Frequency Identification | +| r.m.s. | root mean square | +| WBAN | Wireless Body Area Communication | +| Wi-Fi | Wireless Fidelity | + +# **5 Conventions** + +None. + +# **6 Description of the body-worn device environment** + +### **6.1 Typical configuration of the body-worn device environment** + +Many people use body-worn devices to monitor human health and exercise. The wireless network around the human body connects to the Internet and other networks to exchange information with other nodes or the remote centre. + +If several body-worn devices are located in a person's body area, a high deployment density of wireless equipment results and produces a complex radiated EM environment. + +Figure 1 shows a typical layout scenario consisting of body-worn devices and the surrounding body area environment. In Figure 1, affected objects can be classified by wearable centre node or body-worn device according to coupling mechanism. + +The body-worn device environment usually has the following features. + +- 1) Typical dimensions of the body-worn device environment is usually defined as $2\text{ m} \times 2\text{ m} \times 2\text{ m}$ . +- 2) The number of body-worn devices on one person is typically in the range 1-10. +- 3) Most person have at least one mobile phone and possibly several body-worn devices. +- 4) There is typically one ISM band body-worn device in each body-worn device node. +- 5) Depending on the number of body-worn device nodes, there may be two or three ISM band devices for everybody. +- 6) It is common to find two personal node clusters within a 3 m separation distance in a crowded area. + +![Figure 1: Typical body-worn device environment. A silhouette of a person is shown within a 3D rectangular prism representing a 2m x 2m x 2m volume. The prism's dimensions are labeled 'a' (width), 'b' (depth), and 'c' (height). Four numbered callouts point to specific body-worn devices: 1) glasses on the head, 2) a mobile phone at the waist, 3) a shoe on the foot, and 4) a watch on the wrist. The label 'K.133(18)_F01' is at the bottom right of the diagram.](c37fe03d7cad74ad675a0eb16aa43821_img.jpg) + +Figure 1: Typical body-worn device environment. A silhouette of a person is shown within a 3D rectangular prism representing a 2m x 2m x 2m volume. The prism's dimensions are labeled 'a' (width), 'b' (depth), and 'c' (height). Four numbered callouts point to specific body-worn devices: 1) glasses on the head, 2) a mobile phone at the waist, 3) a shoe on the foot, and 4) a watch on the wrist. The label 'K.133(18)\_F01' is at the bottom right of the diagram. + +**Figure 1 – Typical body-worn device environment [b-electfans.com]** + +The body-worn devices layout is shown in Figure 1. The volume, $abc$ , is $2\text{ m} \times 2\text{ m} \times 2\text{ m}$ [one wearable centre node (labelled 2), such as a handset with an ISM band communication module, is installed at waist height of about 1 m]. Three body-worn devices (labelled 1, 4 and 3) are located at heights of about 1.7 m, 1.0 m and 0.0 m around the head, the wrist and the foot as glasses, watch and shoe, respectively. Other body-worn devices can be used, such as an intelligent waistband or intelligent walking stick. + +### 6.2 Powering and ports + +There are at least two kinds of powering mechanism for body-worn devices: + +- 1) powered by battery only – this kind of device has an enclosure port only; +- 2) powered by battery, and can be powered or charged through a direct current (DC) power input port (barrel port or USB port etc.) or alternating current (AC) power input port. + +### 6.3 Mobility + +With movement, body-worn devices can work in several typical EM environments – commercial, residential, industrial and so on. This Recommendation takes this feature into account. However, consideration of the speed of mobility to the EM environment is under study. + +### 6.4 Possibility of interference + +Interference can occur because the operating frequency of the devices is in the 2.4 GHz, 13.56 MHz or other frequency band. + +Considering that telecommunication equipment density is very high in some areas and that a metal frame of a cabin reflects electromagnetic waves, the problem of electromagnetic compatibility (EMC) can be severe. The transmission rate of a wireless local area network (LAN) system can be greatly affected in this situation. + +Refer to [ITU-T K.79] to analyse the possibility of interference in the 2.4 GHz ISM band. + +When body-worn devices operate on commercial or industrial premises, such as a hospital or factory, interference from ISM devices can affect body-worn devices. + +# 7 Typical phenomena in the electromagnetic environment of body-worn equipment + +In the 2.4 GHz and 13.56 MHz bands, typical phenomena in the EM environment of body-worn equipment are as follows. + +- a) Conducted high-frequency phenomena: + - direct-conducted continuous wave; + - transients. +- b) Radiated high frequency phenomena: + - radiated (continuous wave) oscillatory disturbances; + - radiated (modulated) signal disturbances; + - radiated (transient) pulsed disturbances. +- c) Electrostatic discharge (ESD) phenomena in the 13.56 MHz or 2.4 GHz band. + +The details of these phenomena are described in the basic EMC Recommendation [ITU-T K.34] and in [IEC TR 61000-2-5]. In the context of this Recommendation and in accordance with the IEC EMC approach, the term "high frequency" applies to frequencies above 9 kHz. + +# 8 Disturbance characteristics and levels in the 2.4GHz and 13.56MHz bands + +### 8.1 Attributes of environment + +Enclosure: + +- radiated signal from ISM services in the 13.56 MHz band; +- radiated signal from portable communication devices in the 2.4 GHz band [e.g., wireless phones, Bluetooth and wireless fidelity (Wi-Fi)]; +- high concentration of multimedia and household equipment (e.g., microwave oven); +- amateur radio in the 2.4 GHz band. + +Alternating current power: + +- high concentration of switched mode power supplies; +- existence of power line telecommunication (PLT) equipment. + +## 8.2 Specification of disturbance characteristics and levels + +According to [ITU-T K.34] and [IEC TR 61000-2-5], the disturbance characteristics and levels in the 13.553-13.567 MHz and 2.400 0-2.483 5 GHz bands are as listed in Tables 1 to 6. + +**Table 1 – Disturbance degrees, levels (in volts per metre, r.m.s.) and distance to source – Radiated continuous oscillatory disturbances** + +| Disturbance degree and corresponding field strength | Phenomena (sources) | +|------------------------------------------------------------|------------------------------------------------------| +| | ISM Group 2 equipment | +| | Transmitter frequencies [MHz] | +| | 13.553 to 13.567
2 400 to 2 500 | +| | Distance to source [m] | +| A (Controlled) | Case-by-case according to the equipment requirements | +| 1 0.3 V/m | $d$ (Note) | +| 2 1 V/m | $d$ (Note) | +| 3 3 V/m | $d$ (Note) | +| 4 10 V/m | $d$ (Note) | +| 5 30 V/m | $d$ (Note) | +| X (harsh) | Case-by-case according to the situation | + +NOTE – ISM group 2 equipment (according to [b-CISPR 11]) is not limited in the power used for operation and therefore there are no limits to be observed for radiated disturbances with regard to EMC. Hence it is not possible to generally calculate distance, $d$ . + +(Source: Table 16 of [IEC TR 61000-2-5].) + +**Table 2 – Disturbance degrees, levels (in volts per metre, r.m.s.) and distance to source – Analogue communication services below 30 MHz** + +| Disturbance degree and corresponding field strength | Phenomena (sources) | +|------------------------------------------------------------|--------------------------------------------------------| +| | Amplitude modulation (AM) broadcasting
$P = 500$ kW | +| | Transmitter frequencies [MHz] | +| | 0.150 – 30 | +| | Distance to source [m] | +| A (Controlled) | Case-by-case according to the equipment requirements | +| 1 0.3 V/m | 16 500 | +| 2 1 V/m | 4 959 | +| 3 3 V/m | 1 650 | +| 4 10 V/m | 430 | +| 5 30 V/m | 378.5 | +| X (harsh) | Case-by-case according to the situation | + +NOTE 1 – No AM broadcasting transmitter is expected in the ISM bands, but spurious emissions of radio frequency (RF) sources may be present in ISM bands if RF filters are not properly implemented. +NOTE 2 – The distances are derived assuming an antenna gain of 2.15 dBi of a half-wavelength dipole antenna and at the lowest frequency. This table provides data for the frequency range 0.150 MHz to 30 MHz for a 500 kW transmitter. Other power levels (50 kW to 2 500 kW) and antenna types (and resulting antenna gains) are also possible. + +(Source: Table 19 of [IEC TR 61000-2-5].) + +**Table 3 – Disturbance degrees, levels (in volts per metre, r.m.s.) and distance to source – Amateur radio bands in the 2.4 GHz band** + +| Disturbance degree and corresponding field strength | Amateur radio station | +|-----------------------------------------------------|---------------------------------------------------------------------------------------------------------------| +| | $P = 1\,500\text{ W}$
$P_{\text{EIRP}} \approx 2\,500\text{ W}$
Transmitter frequencies 2 300-2 450 MHz | +| | Distance to source [m] | +| A (Controlled) | Case-by-case according to the equipment requirements | +| 1 0.3 V/m | 905 | +| 2 1 V/m | 271 | +| 3 3 V/m | 90.5 | +| 4 10 V/m | 27.1 | +| 5 30 V/m | 9.05 | +| X (harsh) | Case-by-case according to the situation | + +NOTE 1 – The distances are derived assuming a power of 1 500 W and an antenna gain of 2.15 dBi of a half-wavelength dipole antenna. Practical limitations restrict antenna gain for lower frequency bands and amplifier power for higher frequency bands. + +NOTE 2 – The above-mentioned power and frequency bands are a summary of all three ITU Regions. The power $P$ is (if not otherwise mentioned) the maximum allowed output power of the amplifier. The power arriving at the antenna and radiated by it is $P_{\text{ANT}}$ and is $P$ reduced by the losses of the feeding cable. For easy calculation of $E$ and $d$ , the effective isotropic power $P_{\text{EIRP}}$ is useful. Most antennas have a direction with maximum radiation, i.e., in that direction they have a significant antenna gain $G_{\text{ISO}}$ compared to an isotropic radiator. $E$ and $d$ of this maximum radiation can be easily calculated by means of $P_{\text{EIRP}}$ , which is obtained by multiplying $P_{\text{ANT}}$ by the isotropic antenna gain $G_{\text{ISO}}$ . $d$ Is the spatial distance from the antenna. A power $P = 1\,500\text{ W}$ fed into a dipole results in an isotropic effective radiated power of $P_{\text{EIRP}} \approx 2\,500\text{ W}$ . In the case of an amateur radio station operating at VHF, UHF, SHF and EHF, many antenna types are possible. Typical resulting antenna gains $G_{\text{ISO}}$ are between about 10 dBi and >30 dBi. These (mostly rotatable) antennas are normally mounted on antenna towers 10 m to 30 m above ground or on a roof. In this case, full field strength will occur only in the direction of the main beam of the antenna. Even for slight deviations from the direction of maximum beam strength, significant reductions of antenna gain are observed. + +The same values for $P_{\text{EIRP}}$ and therefore for $E$ and $d$ in the beam direction for the amateur station in this example could also be obtained with $P = 100\text{ W}$ , a feeding cable attenuation of 2 dB and a directional antenna with an isotropic antenna gain $G_{\text{ISO}}$ of 16 dBi. However, with the same $P_{\text{EIRP}}$ , the probability of disturbance of such an antenna is much lower than that of an omnidirectional antenna, because the beam width is limited in the horizontal and vertical plane. + +(Source: Table 31 of [IEC TR 61000-2-5].) + +**Table 4 – Disturbance degrees, levels (in volts per metre, r.m.s.) and distance to source – Other RF items in 2.4 GHz band** + +| Disturbance degree and corresponding field strength | Wideband data transmission systems and high performance radio local area network (HIPERLAN; Note 1) | Wideband data transmission systems and HIPERLAN terminal (Note 2) | +|-----------------------------------------------------|-----------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------| +| | $P = 0.1 \text{ WERP}$
Transmitter frequencies
2.400 0-2.483 5 GHz | $P = 0.1 \text{ WERP}$
Transmitter frequencies
2.400 0-2.483 5 GHz | +| | Distance to source [m] | | +| A (Controlled) | Case-by-case according to the equipment requirements | | +| 1 0.3 V/m | 58 | 7.4 | +| 2 1 V/m | 17 | 2.2 | +| 3 3 V/m | 5.8 | 0.74 | +| 4 10 V/m | 1.7 | 0.22 | +| 5 30 V/m | 0.58 | 0.074 | +| X (harsh) | Case-by-case according to the situation | | + +NOTE 1 – The absolute gain of wideband data transmission systems/HIPERLAN is assumed to be 20 dBi maximum (for fixed wireless access service). +NOTE 2 – The absolute gain of wideband data transmission systems/HIPERLAN is assumed to be 2.14 dBi (for terminals). +NOTE 3 – ERP: effective radiated power. + +(Source: Table 33 and Table 34 of [IEC TR 61000-2-5].) + +**Table 5 – Disturbance degrees, levels (in volts per metre, r.m.s.) and distance to source – Radio frequency identification systems** + +| Disturbance degree and corresponding field strength (Note 1) | Radio frequency identification (RFID) (Note 2) | RFID ( Note 3) | +|--------------------------------------------------------------|----------------------------------------------------------|--------------------------------------------------------------| +| | $P = 4 \text{ W}$
Transmitter frequencies
13.56MHz | $P = 4 \text{ WEIRP}$
Transmitter frequencies
2450 MHz | +| | Distance to source [m] | | +| A (Controlled) | Case-by-case according to the equipment requirements | | +| 1 0.3 V/m | 3.3 | 36.55 | +| 2 1 V/m | 1.6 | 11 | +| 3 3 V/m | 0.9 | 3.7 | +| 4 10 V/m | 0.49 | 1.1 | +| 5 30 V/m | 0.28 | 0.37 | +| X (harsh) | Case-by-case according to the situation | | + +NOTE 1 – The fields are calculated from Formula B.6 for 13.56 MHz RFID and Formula B.4 for 2 450 MHz RFID in Annex B of [IEC TR 61000-2-5]. +NOTE 2 – See [ISO/IEC 18000-3]. +NOTE 3 – See [ISO/IEC 18000-4], the power level is specified by EIRP, an antenna gain of 0 dBi is assumed. + +(Source: Table 39 of [IEC TR 61000-2-5].) + +**Table 6 – Disturbance degrees, levels (in microamperes per metre, r.m.s.) and distance to source – Radio frequency identification systems** + +| Disturbance degree and corresponding field strength | RFID (Note 2)
$P = 4 \text{ W}$
Transmitter frequencies
13.56 MHz | +|-----------------------------------------------------|----------------------------------------------------------------------------| +| | Distance to source [m] | +| A (Controlled) | Case-by-case according to the equipment requirements | +| 1 3 $\mu\text{A/m}$ | 600 | +| 2 10 $\mu\text{A/m}$ | 180 | +| 3 30 $\mu\text{A/m}$ | 60 | +| 4 100 $\mu\text{A/m}$ | 17 | +| 5 300 $\mu\text{A/m}$ | 5.2 | +| 6 1000 $\mu\text{A/m}$ | 2.7 | +| X (harsh) | Case-by-case according to the situation | + +NOTE 1 – The fields are calculated from Formula B.7 in Annex B of [IEC TR 61000-2-5]. +NOTE 2 – See [ISO/IEC 18000-3]. + +(Source: Table 40 of [IEC TR 61000-2-5].) + +# 9 Interference management + +No significant interference source has yet been identified. This is under study. + +If interference occurs on body-worn equipment, Table 7 may be used by the wearer, the manufacturer or other interested stakeholder to collect information about the case. Information about cases of interference sent to ITU-T SG5 for further study is welcome. See Table 7. + +**Table 7 – Template for submission of information about cases of interference** + +| | | | | | | | | | | | +|-----------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------|------------------|-------|--------|--|--|--|--|--| +| Title | | | | | | | | | | | +| Nature of trouble | malfunction, disturbance, other ( ) | | | | | | | | | | +| | More detail: | | | | | | | | | | +| Environment | 1. Residence                      2. Office                      3. Outdoor
4. Industrial area              5. Telecom centre
6. Others ( ) | | | | | | | | | | +| Situation, configuration, measured data, etc. (Please add figures, if necessary.) | | | | | | | | | | | +| | | | | | | | | | | | +| Source of EM interference | | | | | | | | | | | +| Type of interference | | Characteristics of the interferences | | | | | | | | | +| | | Type | Frequency (band) | Level | Others | | | | | | +| Conducted | Voltage or current | Continuous | Hz | [ ] | | | | | | | +| | | Transient | Hz | [ ] | | | | | | | +| Radiated | Electromagnetic wave (field) | Continuous | Hz | [ ] | | | | | | | +| | | Transient | Hz | [ ] | | | | | | | + +# Appendix I + +## **Study roadmap of the electromagnetic environment and electromagnetic compatibility issues of body-worn devices and Bluetooth v4** + +(This appendix does not form an integral part of this Recommendation.) + +The number of body-worn devices sold annually exceeded 100 million in 2016. There are more developers working on applications for body-worn devices [b-WTST]. The EMC of body-worn devices needs study. Furthermore, the EM environment and EMC failure cases and problems require collection and study. + +### **I.1 Bluetooth v4 and the body-worn device electromagnetic environment** + +Most body-worn devices use Bluetooth v4 for data exchange, as it features very low power consumption and high data rates. The EM environment when using Bluetooth v4 in the 2.4 GHz band needs study; to optimize power consumption, devices could switch between sleep and working mode. The EM environment characteristics of wake-up and sleep modes require collection and study. + +### **I.2 Cases of electromagnetic compatibility failure in body-worn devices** + +A few EMC failure cases have been reported. Big EMC problems are not found now with body-worn devices. However, body-worn device applications increase year on year; there are some healthcare and medical body-worn devices that may be interfaced with other normal use body-worn devices. Any EMC interference cases need continuous collection and study. + +## **I.3 Proposed procedure for the study of electromagnetic compatibility of body-worn devices** + +The following steps are proposed: + +- 1) collection of EMC failure cases of body-worn devices; +- 2) study of EMC failure cases; +- 3) collection of EMC test data and results of body-worn devices; +- 4) comparison and study of test data and results; +- 5) drafting of EMC requirements and test conditions. + +# Bibliography + +- [b-ITU-T K.91] Recommendation ITU-T K.91 (2018), *Guidance for assessment, evaluation and monitoring of human exposure to radio frequency electromagnetic fields.* +- [b-elecfans] [http://www.elecfans.com/consume/wearable\\_devices.html](http://www.elecfans.com/consume/wearable_devices.html) +- [b-CISPR 11] CISPR 11:2016, *Industrial, scientific and medical equipment – Radio-frequency disturbance characteristics – Limits and methods of measurement.* +- [b-WTST] Wade J (2017). *Wearable technology statistics and trends 2018*. Leeds: Smart Insights (Marketing Intelligence). + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.134-201811-I_PDF-E/raw.md b/marked/K/T-REC-K.134-201811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..0c388a4a703ad311f6ba72502893eabdc6d3f14a --- /dev/null +++ b/marked/K/T-REC-K.134-201811-I_PDF-E/raw.md @@ -0,0 +1,733 @@ + + +International Telecommunication Union + +# **ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +# **K.134** + +(11/2018) + +### SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Protection of small-size telecommunication +installations with poor earthing conditions** + +Recommendation ITU-T K.134 + +**ITU-T** + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a blue globe with a red lightning bolt striking it. To the right of the globe, the text "International Telecommunication Union" is written in blue. + +ITU logo + +International +Telecommunication +Union + + + +# Recommendation ITU-T K.134 + +# Protection of small-size telecommunication installations with poor earthing conditions + +## Summary + +Recommendation ITU-T K.134 provides engineering solutions for lightning protection and safety of small-size telecommunication installations under poor earthing conditions. These protection measures compromise alternatives due to restrictions of circumstance or expense. These protection measures are not common requirements for most circumstances and have defined conditions for certain applications. The selection of appropriate and feasible solutions is helpful to acquire the best technology to cost ratio. + +Accompanying the miniaturization development trends of network termination units, more and more telecommunication installations, e.g., wire or wireless access units, are being installed in customer premises or other uncontrolled places. Compared with dedicated telecommunication buildings, these installation environments may be more complex and severe. Recommendations ITU-T K.66 and ITU-T K.120 provide bonding and earthing requirements for customer premises and miniature base stations, respectively. However, in some scenarios, it may be very difficult or expensive to satisfy these requirements. If ignored, there is a risk of equipment damage or human safety due to lightning strikes or electric shock. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.134 | 2018-11-13 | 5 | 11.1002/1000/13713 | + +## Keywords + +Earthing, lightning protection, safety, small-size telecommunication installation. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2019 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|----------------------------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 2 | +| 3.1 Terms defined elsewhere ..... | 2 | +| 3.2 Terms defined in this Recommendation..... | 3 | +| 5 Conventions ..... | 4 | +| 6 General consideration ..... | 4 | +| 7 Protection under no earthing connection ..... | 5 | +| 7.1 Protection for electric safety..... | 5 | +| 7.2 Lightning protection ..... | 8 | +| 8 Protection under long earthing conductor..... | 11 | +| 8.1 Consideration of hazards ..... | 11 | +| 8.2 Protection measures..... | 12 | +| 9 Protection under high earth resistance ..... | 13 | +| Annex A – Enclosure live voltage detection..... | 14 | +| Appendix I – Possible hazards of electric shock for SSIs in a.c. TN system ..... | 16 | +| Appendix II – Possible hazards of electric shock for SSIs in a.c. TT or IT system ..... | 18 | +| Appendix III – Possible hazards of electric shock for SSIs powered by up to 400VDC IT system ..... | 19 | +| Bibliography..... | 20 | + + + +# Protection of small-size telecommunication installations with poor earthing conditions + +# 1 Scope + +This Recommendation: + +- provides engineering solutions for lightning protection and safety for small-size telecommunication installations under poor earthing conditions. These protection measures are not common requirements for most circumstances and have defined conditions for certain applications. If these installations have equivalent inherent capacity and function, the same results can be acquired; +- is not intended to replace traditional rules on bonding configurations and earthing. These protection measures compromise alternatives under poor earthing conditions due to restrictions of circumstance or expense; +- is intended to apply to installations powered by a.c. mains and comply with [IEC 60364 series] or national standards bodies on a.c. power installations; +- is intended to apply to installations powered by remote power output up to 400 VDC IT system and comply with [ETSI EN 302 099] and [ETSI EN 301 605]. + +The applied objects in this Recommendation are small-size telecommunication installations which are owned by network operators and controlled by skilled or trained personnel. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.21] Recommendation ITU-T K.21 (2018), *Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents.* +- [ITU-T K.66] Recommendation ITU-T K.66 (2011), *Protection of customer premises from overvoltages.* +- [ITU-T K.75] Recommendation ITU-T K.75 (2016), *Classification of interface for application of standards on resistibility and safety of telecommunication equipment.* +- [ITU-T K.85] Recommendation ITU-T K.85 (2011), *Requirements for the mitigation of lightning effects on home networks installed in customer premises.* +- [ITU-T K.95] Recommendation ITU-T K.95 (2016), *Surge parameters of isolating transformers used in telecommunication devices and equipment.* +- [ITU-T K.98] Recommendation ITU-T K.98 (2014), *Overvoltage protection guide for telecommunication equipment installed in customer premises.* +- [ITU-T K.120] Recommendation ITU-T K.120 (2016), *Lightning protection and earthing of a miniature base station.* + +| | | +|--------------------|--------------------------------------------------------------------------------------------------------------------------------------------------| +| [IEC 60364 series] | IEC 60364-series, Low-voltage electrical installations. | +| [IEC 60364-4-41] | IEC 60364-4-41 (2005), Low-voltage electrical installations – Part 4-41: Protection for safety – Protection against electric shock. | +| [IEC 61558-1] | IEC 61558-1:2017, Safety of transformers, reactors, power supply units and combinations thereof – Part 1: General requirements and tests. | +| [IEC 62305-2] | IEC 62305-2 (2010), Protection against lightning – Part 2: Risk management. | +| [IEC 62368-1] | IEC 62368-1:2018, Audio/video, information and communication technology equipment – Part 1: Safety requirements. | +| [ETSI EN 301 605] | ETSI EN 301 605 V1.1.1 (2013), Environmental Engineering (EE); Earthing and bonding of 400 VDC data and telecom (ICT) equipment. | +| [ETSI EN 302 099] | ETSI EN 302 099 V2.1.1 (2014), Environmental Engineering (EE); Powering of equipment in access network. | + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 breakdown** [b-IEC 61340-1]: Failure, at least temporarily, of the insulating properties of an insulating medium under electric stress. + +**3.1.2 distant power receiver** [ETSI EN 302 099]: Power equipment electrically connected to a Remote Power Unit. + +NOTE – Its function is to supply telecommunications equipment situated at the same location. It may be combined with the item of telecommunications equipment itself. + +**3.1.3 equipment class I** [ITU-T K.66]: Equipment where protection against electric shock is achieved by: + +- 1) using basic insulation; and also +- 2) providing a means of connecting to the protective earthing conductor in the building wiring those conductive parts that are otherwise capable of assuming hazardous voltages if the basic insulation fails. + +**3.1.4 equipment class II** [ITU-T K.66]: Equipment in which protection against electric shock does not rely on basic insulation only, but in which additional safety precautions, such as double insulation or reinforced insulation are provided, there being no reliance on either protective earthing or installation conditions. + +**3.1.5 equipotential bonding** [b-ITU-T Handbook]: An electrical connection putting various exposed conductive parts and extraneous conductive parts at a substantially equal potential. + +Distinction is made between: + +- the main equipotential bonding; +- supplementary equipotential bonding; +- earth-free equipotential bonding. + +Equipotential bonding does not necessarily have to connect to earth. + +**3.1.6 impulse withstand voltage** [b-IEC 60664-2-1]: Highest peak value of impulse voltage of prescribed form and polarity which does not cause breakdown of insulation under specified conditions. + +**3.1.7 inherent protection** [b-ITU-T K.44]: Inherent protection is protection that is provided within the equipment either by virtue of its intrinsic characteristics, by specific design, or by suitable protection components. + +**3.1.8 insulation** (electrical) [b-IEC 62477-1]: Electrical separation between circuits or conductive parts provided by clearance or creepage distance or solid insulation or combinations of them. + +**3.1.9 isolation transformer** [b-IEC 60065]: Transformer with protective separation between the input and output windings + +**3.1.10 miniature base station** [ITU-T K.120]: A type of radio base station (RBS) whose size and RF power are much smaller than typical macro-base station or DBS base stations. + +**3.1.11 multiservice surge protective device (MSPD)** [ITU-T K.85]: A surge protective device (SPD) containing both telecommunications and mains protection. It may also include port protection for video or Ethernet. + +**3.1.12 remote powering (RP)** [ETSI EN 302 099]: Power feeding of a telecommunications equipment by a remote power circuit. + +NOTE – Such a circuit consists of a remote power unit, distribution wiring, and fed receivers. + +**3.1.13 remote power unit (RPU)** [ETSI EN 302 099]: Power unit, connected to the mains or from a centralized power plant, which supplies distant telecommunications equipment. + +**3.1.14 surge isolating transformer (SIT)** [b-IEC 61643-351]: Isolation transformer which has high impulse withstand voltage with/without electrostatic screen between input and output windings. + +**3.1.15 system** [b-ITU-T Handbook]: An electrical system consisting of a single source of electrical energy and an installation. Types of system are identified as follows, depending upon the relationship of the source, and of exposed-conductive-parts of the installation, to Earth. Further details of these systems can be found in the document IEC 60364-4: + +- **TN system**: a system having one or more points of the source of energy directly earthed, the exposed-conductive-parts of the installation being connected to that point by protective conductors. +- **TN-C system**: in which neutral and protective functions are combined in a single conductor throughout the system, +- **TN-S system**: having separate neutral and protective conductors throughout the system, +- **TN-C-S system**: in which neutral and protective functions are combined in a single conductor in part of the system. +- **TT system**: a system having one point of the source of energy directly earthed, and exposed-conductive-parts of the installation being connected to earth electrodes electrically independent of the earth electrodes of the source. +- **IT system**: a system having no direct connection between live parts and Earth, the exposed-conductive-parts of the electrical installation being earthed. + +## **3.2 Terms defined in this Recommendation** + +This Recommendation defines the following terms: + +**3.2.1 enclosure live voltage detection**: Function intended to detect whether or not a conductive enclosure is live. + +**3.2.2 poor earthing conditions**: The actual situations which hinder the construction of valid earthing and bonding configurations compliant with the requirements of the relevant ITU-T K-series Recommendations, e.g., [ITU-T K.66] and [ITU-T K.120], due to the restriction of circumstance or expense. + +**3.2.3 small-size telecommunication installation (SSI):** A telecommunication installation which meets the following conditions: + +- the volume is small. The installation may contain a single equipment or a case, or a site with several interconnected equipment in close proximity; +- power consumption is low and usually less than 1 kW. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-----|-------------------------------------------| +| LPS | Lightning Protection System | +| PE | Protective Earth | +| PEN | Protective Earth Neutral | +| RP | Remote Powering | +| RPU | Remote Power Unit | +| SIT | Surge Isolating Transformer | +| SPC | Surge Protective Component | +| SPD | Surge Protective Device | +| SSI | Small-Size telecommunication Installation | +| VDR | Voltage Dependent Resistor | + +# **5 Conventions** + +None. + +# **6 General consideration** + +The concept and purpose of earthing is introduced in [b-ITU-T Handbook]. [ITU-T K.66] and [ITU-T K.120] also provide requirements on valid bonding and earthing for customer premises and miniature base stations, respectively. In some scenarios, it may be very difficult or expensive to satisfy these requirements. There may be a conflict between installation requirements of a small-size telecommunication installation (SSI) and their practical circumstances. If ignored, there is a risk of equipment damage or human safety due to lightning surges or electric shock. + +Poor earthing conditions, often met in practice, are as follows: + +- no earthing connection; +- long earthing conductor; +- high earth resistance. + +In general, for the condition of no earthing connection, there may be electrical safety hazards and lightning protection issues. For the other two conditions, the possible issues are protection from lightning surges. + +NOTE 1 – There are also electrical safety hazards when the resistance of the earthing conductor or earth resistance is extremely high, which is not considered in this Recommendation. For more information, refer to [IEC 60364 series]. + +These possible hazards are also related to other factors such as the type of equipment concerned with protection against electrical shock, the type of power feeding system, lightning risk level, etc. Considering the complexity of these scenarios, it is convenient and feasible to adopt additional engineering solutions for these SSIs according to local circumstances. The selection of appropriate + +and feasible solutions depends on local conditions and is helpful when implementing the best technology to cost ratio. + +Appropriate earthing conditions must be satisfied in the following scenarios: + +- valid earthing conditions are required for functional (e.g., signalling or testing) purposes or electromagnetic compatibility (EMC) requirements; +- the SSI is located in a highly-exposed environment where there is a significant risk of a direct lightning strike to it or to the line immediately adjacent to it. + +NOTE 2 – If there is an inconsistency between a requirement in this Recommendation and a requirement of the domestic laws and regulations relating to electrical safety, the requirement of the domestic laws and regulations shall apply. + +# **7 Protection under no earthing connection** + +The risk derived from the absence of earthing connection is electric shock and lightning; these may lead to human injury and/or equipment damage. The selection of additional protection measures should consider the possible influence on lightning protection and safety according to practical conditions. + +## **7.1 Protection for electric safety** + +### **7.1.1 Analysis of risk scenarios** + +The possible hazard concerning electric safety under no earthing connection is related to the type of equipment and power feeding system, as follows. + +- Type of equipment concerning the precaution against electric shock. + +The common types of SSIs are class I and class II. For class II equipment with non-metallic enclosures, the hazard of electric shock has nothing to do with poor earthing conditions. But for class I equipment and class II equipment with metallic enclosures, the influence of no earthing connection on safety should be considered. + +- Type of power feeding system. + +For a.c. TN systems, the protective earth (PE) or protective earth neutral (PEN) conductor is always laid along with live conductors, the earthing connection is easy to achieve in TN systems as long as it has been confirmed valid on site. However, if equipment is outside the main equipotential bonding network, e.g., some outdoor equipment powered by an adjacent building, the possible hazards of electric shock also exist in special conditions. Related information and requirements are introduced in Appendix I. + +For a.c. TT and IT system, the earthing connection should be implemented through hard-wired conductors to local earth. If there are no earthing connections, the risk of electric shock shall be considered. Related information and requirement are introduced in Appendix II. + +For up to 400 VDC systems, d.c. IT systems are generally used. Earthing connections should be implemented through hard-wired conductors to local earth. If there are no earthing connections, the risk of electric shock shall be considered. Related information and requirements are introduced in Appendix III. + +### **7.1.2 Protection measures** + +When a reliable earthing connection is difficult to achieve, the following measures can be selected according to local conditions. + +#### 7.1.2.1 Adopting class II equipment + +If requirements for mechanical strength or other relative abilities can be degraded, then class II equipment can be adopted. + +The following design guidelines are suggested to avoid the hazard of electric shock: + +- reinforced or double insulation shall be used between live parts and the enclosure, the detailed design requirements shall comply with class II equipment of [IEC 62368-1]; and +- equipment with metallic enclosures may be 'live' under some fault conditions. It is recommended to use enclosure live voltage detection to warn service personnel that there may be dangerous voltage on the enclosure; this is described in Annex A; and +- to protect an installation against a lightning surge, a surge protective device (SPD) or surge protective component (SPC) between live parts and the metallic enclosure is permitted. The SPD or SPC shall comply with the electric strength and the external clearance and creepage distance requirements with reinforced insulation, and the relevant IEC standard (e.g., IEC 61643 series). A voltage dependent resistor (VDR) alone, cannot be used to bridge reinforced or double insulation; +- it is also recommended to add an insulating surface on the metallic enclosure or other accessible conductive parts to avoid contact with the public. + +#### 7.1.2.2 Adding insulation + +An SSI can be placed into an insulation case whose degree of protection level is not less than IPxxB or IP2X. This case should be locked or managed to ensure that the inner conducted parts cannot be handled by the public. The insulation case acts as double insulation and the entire case could be regarded as "class II equipment". All conducted parts in the case should be interconnected through local equipotential bonding. For detailed requirements refer to clause 412.2.2 in [IEC 60364-4-41]. + +To remind service personnel of the potential for electric shock in this case, the following warning sign and language shall be required to be placed on the equipment case. + +![Warning sign: a lightning bolt inside a triangle, representing electric shock hazard.](53298644c66fa3fca81d6eec654afec5_img.jpg) + +Warning sign: a lightning bolt inside a triangle, representing electric shock hazard. + +IEC 60417-6042 + +"WARNING" or equivalent word or text, and + +"HIGH TOUCH CURRENT" or equivalent text + +"DISCONNECT SUPPLY ESSENTIAL BEFORE MAINTENANCE EQUIPMENT" or equivalent text. + +The large area metallic parts of the service access area in the insulation case may be live under some fault conditions, and enclosure live voltage detection may be used to warn service personnel that there may be dangerous voltage on the enclosure. + +#### 7.1.2.3 Using an isolation transformer for electrical separation + +##### 7.1.2.3.1 Rational + +Using an isolation transformer for electrical separation is a valid protection measure against indirect contact electric shock. Figure 1 shows a typical layout. When a contact fault of single phase to conducted parts occurs, because the secondary side of the transformer is floating and the fault current ( $I_d$ ) would flow back to the transformer (T) through the contact resistance ( $R_A$ ) and the very small capacitance to earth (C), the fault current and the fault voltage ( $U_t$ ) on the conducted part is very low and electric shock can be avoided to the most extent. + +The length of the wiring system served by an isolation transformer shall not exceed 50 m. Flexible cables and cords shall be visible throughout any part of their length susceptible to mechanical damage. + +Any equipment with a metallic enclosure may be "live" under some fault conditions; it is recommended to use enclosure live voltage detection to warn service personnel that there is a possibility of dangerous voltage on the enclosure, and/or to install a residual current device, which opens the circuit at 10 mA, on the secondary side of the isolation transformer. + +To remind service personnel of the potential risk of electric shock in some cases, a warning sign and language as described in clause 7.1.2.2 shall be required. + +When there is a fault between two phases, the circuit would be disconnected by the disconnection device due to high fault current. + +![Figure 1 – A typical layout using an isolation transformer for electrical separation](ff0952ef692c9d960ce5f6708bcc9711_img.jpg) + +The diagram illustrates an electrical circuit for isolation. On the left, input lines L and N enter an isolation transformer (T). The secondary side of the transformer has a fuse on the top line. A current $I_d$ flows through the top conductor. A load is shown on the right, enclosed in a metallic box. A fault is indicated by a jagged arrow pointing from the top conductor to the enclosure. A voltage $U_t \ll 50\text{ V}$ is measured between the enclosure and the ground. A capacitor $C$ is shown connected between the bottom conductor and ground. A resistance $R_E$ is shown in series with a ground connection from the enclosure, with current $I_d$ flowing through it. The diagram is labeled K.134(18)\_F01 at the bottom right. + +Figure 1 – A typical layout using an isolation transformer for electrical separation + +**Figure 1 – A typical layout using an isolation transformer for electrical separation** + +- NOTE – 1) The installation location of equipment shall be selected to avoid the risk of possible contact with other live conductors; +- 2) The isolation transformer should conform with the requirements for Class II transformer which are regulated in [IEC 61558-1]. + +###### 7.1.2.3.2 Protection methods for small systems + +An isolation transformer can also serve a small system including several equipment and not be connected to local earth. When the $L_1$ (or $L_2$ ) conductor of one piece of equipment makes contact with the enclosure while the $L_2$ (or $L_1$ ) conductor of another piece of equipment contacts the enclosure, the power supply of both pieces of equipment is not interrupted. An electric shock may happen if service personnel accidentally come in contact with both equipment enclosures simultaneously. Therefore, the risk of electric shock shall be considered. + +The available solutions for this hazard is as follows: + +If equipment is interconnected through local equipotential bonding without earthing, protection against electric shock can be achieved. Equipotential bonding without earthing can be implemented through hard-wired conductors or via the PE conductor of the triplex hole outlet at the secondary side of the transformer. Typical layouts are shown in Figures 2 and 3. + +Additionally, it is recommended to use enclosure live voltage detection to warn service personnel that there is dangerous voltage on the enclosure. + +![Figure 2: A typical layout for serving equipment through hard-wired conductors as equipotential bonding. The diagram shows a power source with terminals L and N connected to an isolation transformer. The secondary of the transformer is connected to lines L1 and L2. A current I_d is shown flowing from the transformer. Two pieces of equipment are connected to L1 and L2. Each piece of equipment has a ground connection labeled R_E1 and R_E2. A dashed line labeled 'Equipotential bonding' connects the ground connections of the two pieces of equipment. The diagram is labeled K.134(18)_F02.](4801720824e4b5e2361a5564f91cfb70_img.jpg) + +Figure 2: A typical layout for serving equipment through hard-wired conductors as equipotential bonding. The diagram shows a power source with terminals L and N connected to an isolation transformer. The secondary of the transformer is connected to lines L1 and L2. A current I\_d is shown flowing from the transformer. Two pieces of equipment are connected to L1 and L2. Each piece of equipment has a ground connection labeled R\_E1 and R\_E2. A dashed line labeled 'Equipotential bonding' connects the ground connections of the two pieces of equipment. The diagram is labeled K.134(18)\_F02. + +**Figure 2 – A typical layout for serving equipment through hard-wired conductors as equipotential bonding** + +![Figure 3: A typical layout for serving equipment through the PE conductor of the triplex hole outlet as equipotential bonding. The diagram shows an isolation transformer connected to a plug and outlet. The plug and outlet are connected to two pieces of equipment. A dashed line labeled 'Equipotential bonding using PE conductor in triplex hole outlet' connects the ground connections of the two pieces of equipment. The diagram is labeled K.134(18)_F03.](4ee27dbf5ef12e7b58b0ef0937bc5a5e_img.jpg) + +Figure 3: A typical layout for serving equipment through the PE conductor of the triplex hole outlet as equipotential bonding. The diagram shows an isolation transformer connected to a plug and outlet. The plug and outlet are connected to two pieces of equipment. A dashed line labeled 'Equipotential bonding using PE conductor in triplex hole outlet' connects the ground connections of the two pieces of equipment. The diagram is labeled K.134(18)\_F03. + +**Figure 3 – A typical layout for serving equipment through the PE conductor of the triplex hole outlet as equipotential bonding** + +## 7.2 Lightning protection + +### 7.2.1 Protection against lightning + +The need for lightning protection is determined by performing a risk assessment according to [IEC 62305-2], which compares the risk value $R_s$ as the sum of all risk components, with the tolerable risk value $R_T$ . In this Recommendation, the risk of loss of human life ( $R_1$ ) and the risk of loss of service ( $R_2$ ) are considered. + +The related information about the installation environment should first be investigated to perform a risk assessment. The main factors to be considered are as follows: + +- the geographical environment where the SSI is installed, e.g., urban environment, suburban environment or rural environment, as defined in [IEC 62305-2]; +- the lightning ground flash density, or roughly the keraunic level; +- the lightning protection zone (LPZ) where the SSI is installed; +- the type of telecommunication network, e.g., buried or aerial cable, screened or unscreened cable, cable shield installed or not installed; +- the type of power network, e.g., buried or aerial cable, screened or unscreened cable, cable shield installed or not installed, neutral bonded or not bonded to PE; + +- the type of structure construction e.g., timber, brick or reinforced concrete; +- whether or not protection measures have been used at the structure or by the services; +- equipment resistibility level. + +The risk of loss of human life ( $R_1$ ) for telecommunication equipment users or maintenance personnel is normally only required to be considered when there is a significant risk of a direct lightning strike to the SSI or a direct strike to one of the services near the SSI. When the risk $R_1$ is less than the tolerable risk $R_{T1}$ , the SSI is considered inherently protected against direct lightning. When $R_1 > R_{T1}$ , valid earthing via a connection to a lightning protection system (LPS) and the corresponding SPDs are normally the best measures to be adopted. + +To minimize the risk of damage to equipment, the risk of loss of service ( $R_2$ ) should be evaluated and compared to the tolerable risk of loss of service value $R_{T2} = 10^{-3}$ or a lower value according to the decision of the network operator. Even when $R_1 < R_{T1}$ , $R_2$ should be evaluated in accordance with [IEC 62305-2]. [ITU-T K.85] also provides assessment methods and examples of $R_2$ for equipment installed in customer premises. + +When the risk $R_2$ is less than the tolerable risk $R_{T2}$ , the protection for electric safety is only considered, the corresponding measures are introduced in clause 7.1. + +When $R_2 > R_{T2}$ , protection is recommended and the knowledge of the risk component values guides the protection designer in selecting the most adequate protective measures to protect the equipment. The selection of protection measures depends on the convenience of valid earthing and a comparison of expenses. For protection measures under valid earthing refer to [ITU-T K.66], [ITU-T K.120] and other relative recommendations. The protection measures under no earthing connection are introduced in clause 7.2.2. + +At times, to avoid an excessive workload resulting from risk assessment where there are large numbers of sites in a project, a simplified approach for the evaluation of the lightning risk level according to installation scenarios is also adopted. For relative information refer to [ITU-T K.120]. + +### 7.2.2 Protection measures under no earthing connection + +A lightning surge along the connected metal lines needs to be withstood via an insulation barrier, or by bypassing via SPDs or SPCs, to attain reliable protection for SSIs. The absence of an earthing connection means there is no safe path to bleed the lightning surge; this may cause damage to equipment or injury to personnel when the insulation barrier breaks down due to the lightning overvoltage. + +Using isolation protection to block the surge and prevent the breakdown between ports of the SSI or its surroundings is an appropriate solution under no earthing connection. However, when considering the restrictions of volume and expense, the isolation level of the isolation protection is not enough to bear the overvoltage derived from a direct lightning hit. The lightning risk introduced in clause 7.2.1 and the configuration of ports of an SSI should be considered. + +The SSI can be viewed as a "black box" with a variety of ports. For information on the classification of external and internal ports, refer to [ITU-T K.75]. A mains port is always an external port. The most important item for lightning protection of SSIs is the protection between these ports. The implementation of isolation protection for an SSI depends on the configuration of ports. + +For an SSI with a single port (a.c. mains), if the type of equipment is class II or a high level of isolation to surroundings is ensured, only the transverse overvoltage for the external port needs to be considered; if not, isolation measures may be required to prevent possible flashover to its surroundings. A common measure is adding a power surge isolating transformer (SIT) or insulation. Figure 4 provides an illustration for the protection of an SSI with a single port. + +![Figure 4: Illustration for protection of an SSI with a single port (a.c. mains).](fa859e4e468bfb2710a94527f2c504af_img.jpg) + +Figure 4 consists of two sub-diagrams, (a) and (b), illustrating the protection of an SSI with a single port connected to AC mains. + +- a) for Class II SSI:** A Class II SSI is connected to AC mains (L and N lines). A differential surge protector (1) is connected between the L and N lines before the SSI. The SSI itself is labeled with 1). +- b) for Class I SSI:** A Class I SSI is connected to AC mains (L and N lines) through a Power SIT (2). A differential surge protector (1) is connected between the L and N lines before the Power SIT. The Power SIT is labeled with 2). The diagram is identified by the code K.134(18)\_F04. + +Figure 4: Illustration for protection of an SSI with a single port (a.c. mains). + +**Figure 4 – Illustration for protection of an SSI with a single port (a.c. mains)** + +NOTE – 1) When the differential surge is expected to exceed the inherent resistibility of equipment or the SIT, the differential protection is needed; + +2) The power SIT needs to conform the corresponding requirements in clause 7.1.2.3 simultaneously. + +For a multi-port SSI, the isolation level between ports and the surroundings should be ensured and the transverse overvoltage for the external ports needs to be attenuated. If the inherent level is not sufficient or the external cables have a hazard of power contact or induction, isolation measures should be adopted. A common measure is adding power SIT, signal SIT or using optical-electric transfer isolation. Figure 5 provides an illustration for the protection of a multi-port SSI. + +![Figure 5: Illustration for protection of a multi-port SSI.](a83ba9e3e2c1e21dd69953a7b09e45b4_img.jpg) + +Figure 5 consists of three sub-diagrams, (a), (b), and (c), illustrating the protection of a multi-port SSI. + +- a) for Class II SSI with two port:** A Class II SSI has two ports. The input port is connected to AC mains (L and N lines) through a differential surge protector (1). The output port is connected to an external or internal cable through a Signal SIT (3). The Signal SIT is labeled with 3). +- b) for Class I SSI with two port:** A Class I SSI has two ports. The input port is connected to AC mains (L and N lines) through a Power SIT (2) and a differential surge protector (1). The output port is connected to an external cable through a Signal SIT (3). The Power SIT is labeled with 2). +- c) for SSI with multi-port:** A multi-port SSI has multiple ports. The input port is connected to AC mains (L and N lines) through a Power SIT (2) and a differential surge protector (1). Two output ports are shown, each connected to an external cable through a Signal SIT. The Signal SITs are labeled with 1) and 2). The diagram is identified by the code K.134(18)\_F05. + +Figure 5: Illustration for protection of a multi-port SSI. + +**Figure 5 – Illustration for protection of a multi-port SSI** + +NOTE – 1) When the differential surge is expected to exceed the inherent resistibility of equipment or the SIT, the differential protection is needed; + +2) The power SIT needs to conform the corresponding requirements in clause 7.1.2.3 simultaneously; + +3) If the external cable has the risk of power contact or induction, the signal SIT is needed. + +The relative requirements about the surge parameters of signal SIT could refer to [ITU-T K.95]. + +In any case, equipotential bonding within the SSI should be ensured. A metal-free optical-fibre cable is recommended, if possible. If an optical-fibre cable with a metallic component or metallic sheath is used, the metallic component or sheath should be isolated with other metal parts. + +The rated impulse withstand voltage for these isolation measures is required to be not less than 10 kV (1.2/50 us). In field applications, some protection measures, e.g., the power SIT and insulation case, are easy to implement in order to provide a higher isolation level (e.g., 30 kV or even higher), which can meet the requirement of higher reliability or applying in some severe circumstances. + +NOTE – A power isolation transformer should also have enough insulation level or valid measures to ensure electric safety under fault conditions when a breakdown happens. + +# 8 Protection under long earthing conductor + +## 8.1 Consideration of hazards + +[ITU-T K.66] provides requirements for the maximum length of an earthing conductor, which are shown in Table 2. + +**Table 2 – Requirements for the maximum length of an earthing conductor** + +NOTE – Table 2 taken from [ITU-T K.66]. + +| Mechanism | Maximum length/resistance | +|-------------------------------|---------------------------------------| +| Direct strikes | 1.5 m | +| Induced surges | 10 m | +| Power induction/power contact | 1 Ω (< 50 V a.c. @ 2 times 24 A a.c.) | + +When the earthing conductor of an SSI is long, the possible hazards, which are illustrated through an example in Figure 6, would be: + +- the overvoltage drop on the long earthing conductor is so high that there is a big potential difference between the SSI and its surroundings, which maybe lead to a flashover; +- the bleeding of lightning current would be influenced and the conducted surge along external wires may shift to other vulnerable ports and associated interconnected equipment. Some simulation results under defined conditions for this scenario are provided in [ITU-T K.98] and also demonstrate this influence. + +![Figure 6: Illustration of the hazards under a long earthing conductor. The diagram shows a central 'SSI' (Surge Suppressor Interface) block. On the left, power lines 'L' and 'N' enter the SSI, with a lightning strike symbol 'I' above the 'L' line. On the right, an 'External cable' with conductors 'a' and 'b' connects the SSI to 'Associated equipment'. An 'Internal cable' also connects the SSI to the 'Associated equipment'. A long earthing conductor connects the SSI to a 'MET' (Main Earthing Terminal) which is grounded. A 'surroundings' point is indicated near the earthing conductor. A curved arrow shows a potential difference between the SSI and the surroundings. The diagram is labeled 'K.134(18)_F06'.](b0d4609bc46c2d88a8318706bb5321f7_img.jpg) + +Figure 6: Illustration of the hazards under a long earthing conductor. The diagram shows a central 'SSI' (Surge Suppressor Interface) block. On the left, power lines 'L' and 'N' enter the SSI, with a lightning strike symbol 'I' above the 'L' line. On the right, an 'External cable' with conductors 'a' and 'b' connects the SSI to 'Associated equipment'. An 'Internal cable' also connects the SSI to the 'Associated equipment'. A long earthing conductor connects the SSI to a 'MET' (Main Earthing Terminal) which is grounded. A 'surroundings' point is indicated near the earthing conductor. A curved arrow shows a potential difference between the SSI and the surroundings. The diagram is labeled 'K.134(18)\_F06'. + +**Figure 6 – Illustration of the hazards under a long earthing conductor** + +## 8.2 Protection measures + +For scenarios with long earthing conductors, implementing protection measures need to consider the the lightning risk level, configuration of ports and local circumstances. Common protection measures are shown as follows. + +### 1) Optimization through local equipotential bonding + +Figure 7 shows an example of optimization through local equipotential bonding. The sub-bar is installed close to the SSI and is interconnected with the associated equipment and metal surroundings, which reduces the potential difference and eliminates the risk. However, local equipotential bonding cannot reduce pressure on the external port. + +![Diagram illustrating local equipotential bonding for an SSI (Surge Sensitive Equipment). The SSI is connected to a lightning protection system (L, N) and has external cables (a, b) and internal cables connecting to associated equipment. A sub-bar is connected to the SSI and the associated equipment, and is bonded to the metal surroundings (MET) via a sub-bar. The potential difference between the SSI and the sub-bar is labeled ΔU'.](9b9d2abd741ed4bafe7f78f89961c663_img.jpg) + +The diagram shows a central box labeled 'SSI'. On the left, two lines labeled 'L' and 'N' enter the box, with a lightning symbol and current 'I' indicated above the 'L' line. On the right, two lines labeled 'a' and 'b' exit the box, collectively labeled 'External cable'. Below the SSI, a box labeled 'Associated equipment' is connected via an 'Internal cable'. Below the SSI, a horizontal bar labeled 'sub-bar' is connected. A line labeled 'surroundings' connects the sub-bar to the SSI, with a potential difference $\Delta U'$ indicated. The sub-bar is connected to a ground symbol labeled 'MET'. + +Diagram illustrating local equipotential bonding for an SSI (Surge Sensitive Equipment). The SSI is connected to a lightning protection system (L, N) and has external cables (a, b) and internal cables connecting to associated equipment. A sub-bar is connected to the SSI and the associated equipment, and is bonded to the metal surroundings (MET) via a sub-bar. The potential difference between the SSI and the sub-bar is labeled ΔU'. + +Figure 7 – Illustration of local equipotential bonding + +### 2) Adding SPDs on vulnerable ports + +Adding SPDs on vulnerable ports of the SSI and the interconnected equipment can improve endurance capacity of the ports. The coordination between SPDs and inherent protection should be ensured. For more information, refer to [ITU-T K.66] and [ITU-T K.85]. + +This method cannot reduce the potential difference between the SSI and its surroundings. + +### 3) Adding SITs to block the conducted surge + +The use of external SITs can reduce the magnitude of a conducted surge current to a very small level (capacity current), which prevents the hazards caused by long earthing conductors. For more information about this application, refer to clause 7.2.2 of this Recommendation and [b-ITU-T K.126]. Figure 8 shows an illustration of using SITs. + +SITs cannot bear the overvoltage derived from a direct lightning strike. Thus, this method shall not be used in highly exposed environments where there is a significant risk of a direct lightning strike to it or to the line immediately adjacent to it. + +![Diagram illustrating the use of Signal Isolation Transformers (SITs) for an SSI. A central box labeled 'SSI' is connected to a 'Power SIT' on the left and a 'Signal SIT' on the right. The 'Power SIT' is connected to lines 'L' and 'N' with an arrow labeled 'I'. The 'Signal SIT' is connected to two external cables labeled 'a' and 'b'. An 'Associated equipment' box is connected to the 'SSI' via an 'Internal cable' and to the 'External cable' via an 'Internal cable'. The 'SSI' is also connected to 'surroundings' and a 'MET' (Main Earth Terminal) which is grounded.](9c6461e1e94afae4dec455e69a2ce152_img.jpg) + +K.134(18)\_F08 + +Diagram illustrating the use of Signal Isolation Transformers (SITs) for an SSI. A central box labeled 'SSI' is connected to a 'Power SIT' on the left and a 'Signal SIT' on the right. The 'Power SIT' is connected to lines 'L' and 'N' with an arrow labeled 'I'. The 'Signal SIT' is connected to two external cables labeled 'a' and 'b'. An 'Associated equipment' box is connected to the 'SSI' via an 'Internal cable' and to the 'External cable' via an 'Internal cable'. The 'SSI' is also connected to 'surroundings' and a 'MET' (Main Earth Terminal) which is grounded. + +**Figure 8 – Illustration of using SITs** + +### 4) Using enclosure live voltage detection to alarm for possible danger + +Any equipment with metallic enclosure may be ‘live’ under some fault conditions. Enclosure live voltage detection should be used to warn service personnel that there is dangerous voltage on the enclosure. + +# 9 Protection under high earth resistance + +For lightning protection, the function of the earth network is to provide a valid bleeding path for lightning current and decrease the risk to personnel due to touch and step voltages. The architecture of the earth network seems more important than the specific values of earth resistance. It is also difficult to establish definite requirements about earth resistance, but lower earth resistance is preferred. High earth resistance leads to more pressure for primary protection for external cables from a direct lightning strike. However, it is unreasonable to attempt to achieve lower earth resistance without regard for the expense to implement protection. + +For an SSI located in a low exposure environment, the influence of earth resistance is very small and equipotential bonding is more important. + +For an SSI located in highly exposed environment, the implementation of earth network shall first meet the requirements regulated in [ITU-T K.66] and [ITU-T K.120]. If earth resistance is high, the capacity of primary protection for external cables should be confirmed to be sufficient. Detailed information can be found in Annex E of [b-IEC 62305-1]. In most cases, it is not recommended to intentionally decrease earth resistance for low-cost SSIs. + +## Annex A + +### Enclosure live voltage detection + +(This annex forms an integral part of this Recommendation.) + +Enclosure live voltage detection is used to detect dangerous voltage caused by insulation impedance degradation or breakdown between any input live conductor or circuit and the metallic enclosure of the equipment. + +Enclosure live voltage detection consists of an isolation module, a voltage signal collection (or division) module, a signal regulation module (optional), a signal processing (or comparison) module, and an alarm (local or remote) module, as shown in Figure A.1. + +The isolation module shall comply with the electric strength and the clearance and creepage distance requirements of double or reinforced insulation detailed in [IEC 62368-1]. + +Enclosure live voltage detection shall provide a local or remote alarm on the equipment to remind service personnel that there is dangerous voltage on the equipment. + +Enclosure live voltage detection shall not rely on the earthing of equipment within metallic enclosures. + +![Figure A.1 – Enclosure live detection function diagram. The diagram shows a block diagram of the enclosure live voltage detection system. It includes an Isolation module, a Signal collection module, an Optional Signal regulation module, a Signal processing module, and an Alarm module. The system is connected to live conductors (L or N connection X and N or L connection Y) and the Metal enclosure. The Signal collection module is connected to the Metal enclosure and has an Optional connection with or without earthed. The Signal processing module is connected to the Signal regulation module and the Alarm module. The Signal regulation module is Optional. The Signal collection module, Signal regulation module, and Signal processing module are connected to a common GND line. The diagram is labeled K.134(18)_FA.1.](1a85642ed2356d183ce598f2c8b3ee8b_img.jpg) + +The diagram illustrates the functional architecture of an enclosure live voltage detection system. On the left, two input lines, 'L or N connection X' and 'N or L connection Y', enter a 'Metal enclosure'. These lines connect to an 'Isolation module'. Below the metal enclosure, there is an 'Optional connection with or without earthed' point connected to ground. The 'Isolation module' has an 'Optional connection' to the 'Metal enclosure' and its output connects to a 'Signal collection module'. The 'Signal collection module' is also connected to the 'Metal enclosure' and has an 'Optional connection' to ground. Its output connects to an 'Optional Signal regulation module', which in turn connects to a 'Signal processing module'. The 'Signal processing module' is connected to an 'Alarm module' and to a common 'GND' line. The 'GND' line is also connected to the 'Metal enclosure' via an 'Optional connection'. + +Figure A.1 – Enclosure live detection function diagram. The diagram shows a block diagram of the enclosure live voltage detection system. It includes an Isolation module, a Signal collection module, an Optional Signal regulation module, a Signal processing module, and an Alarm module. The system is connected to live conductors (L or N connection X and N or L connection Y) and the Metal enclosure. The Signal collection module is connected to the Metal enclosure and has an Optional connection with or without earthed. The Signal processing module is connected to the Signal regulation module and the Alarm module. The Signal regulation module is Optional. The Signal collection module, Signal regulation module, and Signal processing module are connected to a common GND line. The diagram is labeled K.134(18)\_FA.1. + +Figure A.1 – Enclosure live detection function diagram + +Example: + +The enclosure live voltage detection circuit contains a detection circuit and a detection method. + +The enclosure live voltage detection circuit consists of an isolation module, a voltage signal collection module, a signal regulation module, a signal processing module, and a remote alarm module. + +The isolation module is used to isolate hazardous live parts, it uses two high-impedance isolation modules with symmetrical impedance. + +The signal collection module is used to sample the voltage $U_x$ that is the ratio voltage between a live conductor and the metallic enclosure, it uses $R_1$ and $R_2$ of equal resistance value to divide voltage, $U_x$ is a differential voltage between the voltage at both ends of the $R_1$ and the voltage at both ends of the $R_2$ multiplied by a certain proportion. + +The signal regulation module is used to regulate the voltage to match the signal processing, it adjusts the signal to a level within an acceptable range of the signal processing module to protect the signal processing module from overvoltage or negative voltage damage. + +The signal processing module is used to calculate the value of $\frac{U_x}{U_{in}}$ , and judge if the device is faulty according to the detection method. $U_{in}$ is the ratio input voltage that the input voltage of the equipment is multiplied by a certain proportion, and is necessary in the detection method. The signal of $U_{in}$ should be connected to the signal processing module. + +The principle detection method is to compare $\frac{U_x}{U_{in}}$ with a setting value or range, when the result meets the setting conditions it indicates that the device is faulty. + +The faults include at least one of the cases as below: + +- 1) the metallic enclosure of equipment is lived; +- 2) the phase conductor and neutral conductor are reversed. + +A detailed circuit diagram is shown in Figure A.2. + +Note: + +X is connected to a target live conductor, + +E is a metallic enclosure of equipment with or without earthing. + +![Circuit diagram for enclosure live voltage detection. The diagram shows five main modules: 1. The first isolation module (containing two isolation transformers, 1A and 1B); 2. The first signal collection module (containing op-amps OPA1, OPA2, OPA3 and resistors R1, R2, R3, R4, R5, R6); 3. The signal regulation module (containing a regulation source, resistors R7, R8, and diodes D1, D2); 4. The signal processing module (containing an AD converter and an MCU with pins aa, ab, ac, ma, mb); 5. An Alarm module. Input X is connected to the live conductor, and E is the metallic enclosure. The isolation module outputs are connected to the signal collection module. The signal collection module output (2c) is connected to the signal regulation module (4a). The signal regulation module output (4b) is connected to the signal processing module (3a). The signal processing module is connected to the alarm module. A common ground (GND) is shown at the bottom.](608f1b5ef8f3dc0723f2b4ea1fb72be2_img.jpg) + +Circuit diagram for enclosure live voltage detection. The diagram shows five main modules: 1. The first isolation module (containing two isolation transformers, 1A and 1B); 2. The first signal collection module (containing op-amps OPA1, OPA2, OPA3 and resistors R1, R2, R3, R4, R5, R6); 3. The signal regulation module (containing a regulation source, resistors R7, R8, and diodes D1, D2); 4. The signal processing module (containing an AD converter and an MCU with pins aa, ab, ac, ma, mb); 5. An Alarm module. Input X is connected to the live conductor, and E is the metallic enclosure. The isolation module outputs are connected to the signal collection module. The signal collection module output (2c) is connected to the signal regulation module (4a). The signal regulation module output (4b) is connected to the signal processing module (3a). The signal processing module is connected to the alarm module. A common ground (GND) is shown at the bottom. + +K.134(18)\_FA.2 + +Figure A.2 – Circuit diagram for enclosure live voltage detection + +## Appendix I + +### Possible hazards of electric shock for SSIs in a.c. TN system + +(This appendix does not form an integral part of this Recommendation.) + +When an SSI is outside the main equipotential bonding network, e.g., some outdoor equipment powered by an adjacent building, the conducted fault voltage along PE or PEN conductors may lead to accidental electric shock. The fault voltage can be produced due to various reasons. In the example demonstrated in Figure I.1, the L conductor is in contact with the earth and the power supply is uninterrupted. For example, if the L conductor falls into a pond. Due to the restriction of the earth resistance of fault point ( $R_E$ ) and the power transformer ( $R_B$ ), the fault current ( $I_d$ ) is small. If the value of $R_B$ and $I_d$ are assumed to be 4 Ω and 20 A, the persistent fault voltage ( $U_f$ ) along PE or PEN conductors is 80 V. For the equipment within the main equipotential bonding network in the building, there is no hazard of electric shock. But for equipment outside the main equipotential bonding network, the persistent fault voltage can lead to an accident. Although there is an RCD on the circuit for the building, it cannot cut off this fault because there is no trigger current. When the earth resistance of the power transformer ( $R_B$ ) is very small or there are many customers which have repetitive earthing in parallel with $R_B$ , these hazards would be decreased. + +![Diagram of a TN-C-S system showing a fault scenario. A power transformer on the left has its secondary connected to L, PEN, and PE conductors. The PEN conductor is earthed at the transformer via resistance R_B. A fault occurs where the L conductor touches the earth at a point with resistance R_E. Fault current I_d flows from the L conductor through the earth back to the transformer. This results in a fault voltage U_f = I_d * R_B across the transformer's earthing resistance. Inside a building, the PEN conductor is split into N and PE. An RCD is installed on the L and N conductors. The building's main equipotential bonding network is connected to the PE conductor and earthed via resistance R_A. Two pieces of equipment are shown: one inside the building connected to the local PE conductor (at 0V), and another outside the building connected to the PE conductor at the fault point. A person touching the outdoor equipment is shown with red dashed lines indicating current flow through their body to the earth, representing a shock hazard. The diagram is labeled 'TN-C-S' and 'K.134(18)_FI.1'.](09955ff8214ffb6947951fc0f60eb6ab_img.jpg) + +Diagram of a TN-C-S system showing a fault scenario. A power transformer on the left has its secondary connected to L, PEN, and PE conductors. The PEN conductor is earthed at the transformer via resistance R\_B. A fault occurs where the L conductor touches the earth at a point with resistance R\_E. Fault current I\_d flows from the L conductor through the earth back to the transformer. This results in a fault voltage U\_f = I\_d \* R\_B across the transformer's earthing resistance. Inside a building, the PEN conductor is split into N and PE. An RCD is installed on the L and N conductors. The building's main equipotential bonding network is connected to the PE conductor and earthed via resistance R\_A. Two pieces of equipment are shown: one inside the building connected to the local PE conductor (at 0V), and another outside the building connected to the PE conductor at the fault point. A person touching the outdoor equipment is shown with red dashed lines indicating current flow through their body to the earth, representing a shock hazard. The diagram is labeled 'TN-C-S' and 'K.134(18)\_FI.1'. + +Figure I.1 – Example of possible hazards of electric shock in a.c. TN system + +The available solutions for these hazards include: + +- a local earthing TT system for the outdoor equipment, which is shown in Figure I.2; or +- class II equipment as described in clause 7.1.2.1, which is shown in Figure I.3; or +- an insulation case as described in clause 7.1.2.2; or +- an isolation transformer as described in clause 7.1.2.3 as electrical separation, which is shown in Figure I.4. + +NOTE – For the first solution, a local earthing connection is needed. The relative requirements can refer to the TT system in [IEC 60364 series]. But in some scenarios, it may be very difficult or expensive to satisfy these requirements. + +![Diagram of a TN-C-S system transitioning to a Local TT system for outdoor equipment. The TN-C-S part includes a transformer with L, PEN, and N conductors, an RCD, and a main equipotential bonding network. The Local TT part includes a separate earth electrode (RA) and a PE' conductor connected to it. A fault current Id flows through the earth. The formula Uf = Id * RB is shown on the left.](c914f51f4427bc672dd0526cfc90ebe9_img.jpg) + +Diagram illustrating the solution of building a local a.c. TT system for outdoor equipment. The system is divided into two parts: TN-C-S and Local TT. The TN-C-S part includes a transformer with L, PEN, and N conductors, an RCD, and a main equipotential bonding network. The Local TT part includes a separate earth electrode ( $R_A$ ) and a PE' conductor connected to it. A fault current $I_d$ flows through the earth. The formula $U_f = I_d \cdot R_B$ is shown on the left. The diagram is labeled K.134(18)\_FI.2. + +Diagram of a TN-C-S system transitioning to a Local TT system for outdoor equipment. The TN-C-S part includes a transformer with L, PEN, and N conductors, an RCD, and a main equipotential bonding network. The Local TT part includes a separate earth electrode (RA) and a PE' conductor connected to it. A fault current Id flows through the earth. The formula Uf = Id \* RB is shown on the left. + +**Figure I.2 – Solution of building a local a.c. TT system for outdoor equipment** + +![Diagram showing the use of Class II equipment (double insulation) for electrical separation. It shows a transformer with L, PEN, and N conductors. Equipment A is connected to the PE conductor and has a fault voltage Uf. Equipment B is a Class II appliance with double insulation and is connected to the N conductor, resulting in 0V at its exposed conductive parts. The diagram is labeled K.134(18)_FI.3.](d734a6ea1b381280f043fcf70391b6db_img.jpg) + +Diagram illustrating the solution of adopting a class II equipment as electrical separation. The system includes a transformer with L, PEN, and N conductors. Equipment A is connected to the PE conductor and has a fault voltage $U_f$ . Equipment B is a Class II appliance with double insulation and is connected to the N conductor, resulting in 0V at its exposed conductive parts. The diagram is labeled K.134(18)\_FI.3. + +Diagram showing the use of Class II equipment (double insulation) for electrical separation. It shows a transformer with L, PEN, and N conductors. Equipment A is connected to the PE conductor and has a fault voltage Uf. Equipment B is a Class II appliance with double insulation and is connected to the N conductor, resulting in 0V at its exposed conductive parts. The diagram is labeled K.134(18)\_FI.3. + +**Figure I.3 – Solution of adopting a class II equipment as electrical separation** + +![Diagram showing the use of an isolation transformer for electrical separation. It shows a transformer with L, PEN, and N conductors. Equipment A is connected to the PE conductor and has a fault voltage Uf. Equipment B is connected to the secondary of an isolation transformer, resulting in 0V at its exposed conductive parts. The diagram is labeled K.134(18)_FI.4.](844077b3034f0030b404207db0ad76b4_img.jpg) + +Diagram illustrating the solution of adopting an isolation transformer as electrical separation. The system includes a transformer with L, PEN, and N conductors. Equipment A is connected to the PE conductor and has a fault voltage $U_f$ . Equipment B is connected to the secondary of an isolation transformer, resulting in 0V at its exposed conductive parts. The diagram is labeled K.134(18)\_FI.4. + +Diagram showing the use of an isolation transformer for electrical separation. It shows a transformer with L, PEN, and N conductors. Equipment A is connected to the PE conductor and has a fault voltage Uf. Equipment B is connected to the secondary of an isolation transformer, resulting in 0V at its exposed conductive parts. The diagram is labeled K.134(18)\_FI.4. + +**Figure I.4 – Solution of adopting an isolation transformer as electrical separation** + +## Appendix II + +### Possible hazards of electric shock for SSIs in a.c. TT or IT system + +(This appendix does not form an integral part of this Recommendation.) + +If class I equipment is powered by an a.c. TT system and is not connected to local earth, the equipment within the metallic enclosure may be lived under a single fault condition, and the risk of electric shock shall be considered. This is shown in Figure II.1. + +![Figure II.1: Diagram of a TT system showing a fault condition. A transformer with L and N windings is connected to a fault voltage source U_f and a grounding resistor R_B. The N conductor is connected to earth. A metallic enclosure A contains a resistor and is connected to the L and N conductors. A person touches the enclosure, and a fault current flows through the body to earth, indicated by a red dashed line. The voltage across the body is labeled U_f. The diagram is labeled K.134(18)_FII.1.](4b87467ad9642943235f48f7d4b59449_img.jpg) + +Figure II.1: Diagram of a TT system showing a fault condition. A transformer with L and N windings is connected to a fault voltage source U\_f and a grounding resistor R\_B. The N conductor is connected to earth. A metallic enclosure A contains a resistor and is connected to the L and N conductors. A person touches the enclosure, and a fault current flows through the body to earth, indicated by a red dashed line. The voltage across the body is labeled U\_f. The diagram is labeled K.134(18)\_FII.1. + +Figure II.1 – Example of possible hazards of electric shock in a.c. TT system + +If class I equipment are powered by an a.c. IT system not connected to local earth, the L (or N) conductor contact with the earth and the power supply does not interrupt, for example, if the L (or N) conductor falls into a pond or its insulation is damaged. The equipment within the metallic enclosure may be lived under a single fault condition, and the risk of electric shock shall be considered. This is shown in Figure II.2. + +![Figure II.2: Diagram of an IT system showing a fault condition. A transformer with L and N windings is connected to a fault voltage source U_f and a grounding resistor R_B. The N conductor is connected to earth through a high impedance resistor R_A. The L conductor is connected to earth through a grounding resistor R_E. A metallic enclosure A contains a resistor and is connected to the L and N conductors. A person touches the enclosure, and a fault current flows through the body to earth, indicated by a red dashed line. The voltage across the body is labeled U_f. The diagram is labeled K.134(18)_FII.2.](5132b3a97ac70fe4765c1e07e66b72b3_img.jpg) + +Figure II.2: Diagram of an IT system showing a fault condition. A transformer with L and N windings is connected to a fault voltage source U\_f and a grounding resistor R\_B. The N conductor is connected to earth through a high impedance resistor R\_A. The L conductor is connected to earth through a grounding resistor R\_E. A metallic enclosure A contains a resistor and is connected to the L and N conductors. A person touches the enclosure, and a fault current flows through the body to earth, indicated by a red dashed line. The voltage across the body is labeled U\_f. The diagram is labeled K.134(18)\_FII.2. + +Figure II.2 – Example of possible hazards of electric shock in a.c. IT system + +The available solutions for these hazards include: + +- class II equipment as described in clause 7.1.2.1; or +- an insulation case as described in clause 7.1.2.2; or +- for the equipment powered by a TT system, an isolation transformer as described in clause 7.1.2.3 as electrical separation; or +- for equipment within a metallic enclosure powered by a TT and IT system, an enclosure live voltage detection as described in Annex A. + +## Appendix III + +### Possible hazards of electric shock for SSIs powered by up to 400 VDC IT system + +(This appendix does not form an integral part of this Recommendation.) + +If class I equipment (distant power receiver/SSI) is powered by a d.c. IT system (remote power unit (RPU)) and is not connected to local earth, the power supply does not interrupt when the + (or -) conductor contacts the earth in the case of an earth fault or insulation breakdown. The metallic enclosure may be lived under a single fault condition, and the risk of electric shock shall be considered, as shown in Figure III.1. + +![Figure III.1: Example of possible hazards of electric shock in d.c. IT system. The diagram shows a Remote Power Unit (RPU) connected to a Cable system. The RPU has two output conductors, V+ (red) and V- (blue). The V+ conductor is connected to the metallic enclosure of a Remote Power Receiver/SSI (RPR/SSI). The V- conductor is connected to a high impedance resistor (RA) and a metal enclosure (MET) which is connected to local earth. The RPR/SSI is also connected to local earth. A person is shown touching the metallic enclosure of the RPR/SSI. The voltage across the person is labeled UF. The diagram is labeled K.134(18)_FIII.1.](e354b57563dae469c00b412b2abdf765_img.jpg) + +Figure III.1: Example of possible hazards of electric shock in d.c. IT system. The diagram shows a Remote Power Unit (RPU) connected to a Cable system. The RPU has two output conductors, V+ (red) and V- (blue). The V+ conductor is connected to the metallic enclosure of a Remote Power Receiver/SSI (RPR/SSI). The V- conductor is connected to a high impedance resistor (RA) and a metal enclosure (MET) which is connected to local earth. The RPR/SSI is also connected to local earth. A person is shown touching the metallic enclosure of the RPR/SSI. The voltage across the person is labeled UF. The diagram is labeled K.134(18)\_FIII.1. + +Figure III.1 – Example of possible hazards of electric shock in d.c. IT system + +If several pieces of class I equipment (RPR/SSI) are powered by a d.c. IT small system (RPU) and are not connected to local earth, when one equipment has a + (or -) conductor in contact with the enclosure and the other equipment also has a - (or +) conductor in contact with the enclosure, both pieces of equipment do not interrupt the power supply. If, for example, two body parts of a service person accidentally contact both enclosures forming an electric shock circuit, then the risk of electric shock shall be considered, as shown in Figure III.2. + +![Figure III.2: Example of possible hazards of electric shock in several class I equipment powered by a d.c. IT system. The diagram shows a Remote Power Unit (RPU) connected to a Cable system. The RPU has two output conductors, V+ (red) and V- (blue). The V+ conductor is connected to the metallic enclosure of a Remote Power Receiver/SSI (RPR/SSI). The V- conductor is connected to a high impedance resistor (RA) and a metal enclosure (MET) which is connected to local earth. The RPR/SSI is also connected to local earth. A person is shown touching the metallic enclosure of the RPR/SSI. The current flowing through the person is labeled Id. The diagram is labeled K.134(18)_FIII.2.](8d325fc12b494e42c9ea7ed2a7f327a6_img.jpg) + +Figure III.2: Example of possible hazards of electric shock in several class I equipment powered by a d.c. IT system. The diagram shows a Remote Power Unit (RPU) connected to a Cable system. The RPU has two output conductors, V+ (red) and V- (blue). The V+ conductor is connected to the metallic enclosure of a Remote Power Receiver/SSI (RPR/SSI). The V- conductor is connected to a high impedance resistor (RA) and a metal enclosure (MET) which is connected to local earth. The RPR/SSI is also connected to local earth. A person is shown touching the metallic enclosure of the RPR/SSI. The current flowing through the person is labeled Id. The diagram is labeled K.134(18)\_FIII.2. + +Figure III.2 – Example of possible hazards of electric shock in several class I equipment powered by a d.c. IT system + +The available solutions for these hazards include: + +- for equipment within a metallic enclosure, enclosure live voltage detection, as described in Annex A; or +- class II equipment as described in clause 7.1.2.1; or +- an insulation case as described in clause 7.1.2.2. + +## Bibliography + +- [b-ITU-T K.44] Recommendation ITU-T K.44 (2017), *Resistibility tests for telecommunication equipment exposed to overvoltages and overcurrents – Basic Recommendation*. +- [b-ITU-T Handbook] ITU-T handbook on Earthing and Bonding (2003). +- [b-IUT-T K.126] Recommendation ITU-T K.126 (2017), *Surge protective component application guide - High frequency signal isolation transformers*. +- [b-IEC 60065] IEC 60065 (2014), *Audio, video and similar electronic apparatus – Safety requirements*. +- [b-IEC 60664-1] IEC 60664-1 (2007), *Insulation coordination for equipment within low-voltage systems – Part 1: Principles, requirements and tests*. +- [b-IEC 60664-2-1] IEC TR 60664-2-1 (2011), *Insulation coordination for equipment within low-voltage systems – Part 2-1: Application guide – Explanation of the application of the IEC 60664 series, dimensioning examples and dielectric testing*. +- [b-IEC 61340-1] IEC 61340-1 (2012), *Electrostatics – Part 1: Electrostatic phenomena – Principles and measurements*. +- [b-IEC 61643-351] IEC 61643-351 (2016), *Components for low-voltage devices – Part 351: Performance requirements and test methods for telecommunications and signalling network surge isolation transformers (SIT)*. +- [b-IEC 62305-1] IEC 62305-1 (2010), *Protection against lightning – Part 1: General principles*. +- [b-IEC 62477-1] IEC 62477-1 (2012), *Safety requirements for power electronic converter systems and equipment – Part 1: General*. +- [b-IEC 62631-1] IEC 62631-1 (2011), *Dielectric and resistive properties of solid insulating materials – Part 1: General*. + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.135-201811-I_PDF-E/raw.md b/marked/K/T-REC-K.135-201811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..b9a6b07c4e80208c3e0517e835e3795774c920fa --- /dev/null +++ b/marked/K/T-REC-K.135-201811-I_PDF-E/raw.md @@ -0,0 +1,514 @@ + + +International Telecommunication Union + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.135** + +(11/2018) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Technical parameters for residual current +operated protective devices with automatic +reclosing feature for telecom applications** + +Recommendation ITU-T K.135 + +ITU-T + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a red lightning bolt striking it, symbolizing telecommunications. To the right of the globe, the text "International Telecommunication Union" is written in blue. + +ITU logo + +International +Telecommunication +Union + + + +# Recommendation ITU-T K.135 + +# Technical parameters for residual current operated protective devices with automatic reclosing feature for telecom applications + +## Summary + +Recommendation ITU-T K.135 provides an overview of the parameters of residual current operated protective devices with an automatic-reclosing feature for telecom applications. + +Such devices with an automatic-reclosing feature (herein referred to as residual current devices with automatic reclosing (RCDAs)), also known as trip-free devices, are used in telecom applications based in central offices or in bureaux and/or stations. They are usually mounted as supplementary protection devices to other forms of protection against direct contact. The parameters reference built-in residual current operated protective devices with automatic-reclosing functionality. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.135 | 2018-11-13 | 5 | 11.1002/1000/13714 | + +## Keywords + +Automatic-reclosing, overcurrent protection, residual current devices (RCDs), self-restoring, trip-free. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2019 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|------|-----------------------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 3.1 | Terms defined elsewhere ..... | 2 | +| 3.2 | Terms defined in this Recommendation ..... | 3 | +| 4 | Abbreviations and acronyms ..... | 3 | +| 5 | Conventions ..... | 3 | +| 6 | Technical requirements..... | 3 | +| 6.1 | Appearance and structure ..... | 3 | +| 6.2 | Enclosure requirement..... | 3 | +| 6.3 | Dielectric properties ..... | 4 | +| 6.4 | Temperature rise ..... | 4 | +| 6.5 | Operating characteristics ..... | 4 | +| 6.6 | Mechanical and electrical life..... | 6 | +| 6.7 | Short-circuit current performance ..... | 6 | +| 6.8 | Test function of the device ..... | 6 | +| 6.9 | Technical requirements for RCD functionally dependent on line voltage ..... | 6 | +| 6.10 | RCD working conditions upon over current of main circuits ..... | 6 | +| 6.11 | RCD performance with surge current..... | 7 | +| 6.12 | Technical requirements for automatic-reclosing devices ..... | 7 | +| 6.13 | Environmental adaption..... | 7 | +| 6.14 | Safety warning..... | 7 | +| | Annex A – RCDA with electric residual current detection function..... | 8 | +| A.1 | Technical rationale ..... | 8 | +| | Bibliography..... | 11 | + + + +# Recommendation ITU-T K.135 + +# Technical parameters for residual current operated protective devices with automatic reclosing feature for telecom applications + +# 1 Scope + +This Recommendation applies to residual current devices (RCDs) with automatic reclosing (RCDAs) and provides an overview of parameters and testing methods. RCDAs are equipped with an automatic-reclosing feature, called trip-free functionality. This Recommendation also covers built-in RCDAs. + +The following device parameters are covered: + +- appearance and structure; +- enclosure; +- dielectric properties; +- temperature rise; +- operating characteristics; +- mechanical and electrical life; +- performance at short-circuit current; +- test function of the device; +- technical requirements for RCDs functionally dependent on line voltage; +- working conditions upon over current of main circuits; +- surge current performance; +- technical requirements for automatic-reclosing devices; +- environmental adaption. + +This Recommendation does not cover: + +- quality assurance requirements. + +This Recommendation covers RCDs with automatic reclosing which are owned by network operators and under the supervision of skilled persons, and used within restricted access areas. + +NOTE – If there is an inconsistency between a requirement in this Recommendation and a requirement of the domestic laws and regulations which relates to electrical safety, the requirement of the domestic laws and regulations shall take priority. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[IEC 60529] IEC 60529 (2013), *Degrees of protection provided by enclosures (IP Code) Edition 2.2.* + +- [IEC 60898-2] IEC 60898-2 (2016), *Electrical accessories – Circuit-breakers for overcurrent protection for household and similar installations – Part 2: Circuit-breakers for AC and DC operation*. +- [IEC 60947-2] IEC 60947-2 (2016), *Low-voltage switchgear and control gear – Part 2: Circuit-breakers*. +- [IEC 61008-1] IEC 61008-1 (2013), *Residual current operated circuit-breakers without integral overcurrent protection for household and similar uses (RCCBs) – Part 1: General rules*. + +# 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 automatic reclosing** [b-IEC 61936-1]: Automatic reclosing of a circuit-breaker associated with a faulted section of a network after an interval of time which permits that section to recover from a transient fault. + +**3.1.2 auxiliary circuit (of a circuit-breaker)** [b-IEC 60898-1]: All the conductive parts of a circuit-breaker intended to be included in a circuit other than the main circuit and the control circuit of the circuit-breaker. + +**3.1.3 conditional residual short-circuit current** [b-IEC 62873-2], $I_{\Delta C}$ : Value of the AC component of a residual prospective current which a residual current device (RCD) without integral short-circuit protection, but protected by a short-circuit protective device in series, can withstand under specified conditions of use and behaviour. + +**3.1.4 conditional short-circuit current (for a residual current device)** [b-IEC 60050-442]: Value of the alternating component of a prospective current, which a residual current device (RCD) without integral short-circuit protection, but protected by a short-circuit protective device in series, can withstand under specified conditions of use and behaviour. + +NOTE – The conditional short-circuit current value is represented by the symbol $I_{NC}$ . + +**3.1.5 mechanical switching device** [b-IEC 62873-2]: Switching device designed to close and open one or more electric circuits by means of separable contacts. + +**3.1.6 rated residual operating current** [b-IEC 61557-6], $I_{\Delta N}$ : Fault current for which the residual current protective device is designed. + +**3.1.7 residual current** [b-IEC 62752], $I_{\Delta}$ : Vector sum of the instantaneous values of the current flowing in the main circuit of the residual current function (expressed as r.m.s. value). + +**3.1.8 residual current device (RCD)** [b-IEC 60755]: Mechanical switching device or association of devices designed to make, carry and break currents under normal service conditions and to cause the opening of the contacts when the residual current attains a given value under specified conditions. + +NOTE – An RCD may also be referred to as a residual current operated protective device. + +**3.1.9 residual making and breaking capacity** [b-IEC 62640], $I_{\Delta M}$ : Value of the alternating component of a residual prospective current which a socket-outlet residual current device (RCD) can make, carry for its opening time and break under specified conditions of use and behaviour. + +**3.1.10 residual non-operating current** [b-IEC 62640], $I_{\Delta NO}$ : Value of residual current at which and below which the residual current device (RCD) does not operate under specified conditions. + +**3.1.11 restricted access area** [b-IEC 62368-1]: Area accessible only to skilled persons and instructed persons with the proper authorization. + +**3.1.12 skilled person** [b-IEC 62368-1]: Person with relevant education or experience to enable him or her to identify hazards and to take appropriate actions to reduce the risks of injury to themselves and others. + +**3.1.13 trip-free mechanism of a residual current device** [b-IEC 60755]: Mechanism, the moving contacts of which return to and remain in the open position when the opening operation is initiated after the initiation of the closing operation, even if the closing command is maintained. + +NOTE – To ensure proper breaking of the current which may have been established, it may be necessary that the contacts momentarily reach the closed position. + +## **3.2 Terms defined in this Recommendation** + +None. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +RCD Residual Current Device + +RCDA Residual Current Device with Automatic reclosing + +NOTE – In the USA, an RCD is referred to as a ground fault interrupter (GFI). + +# **5 Conventions** + +None. + +# **6 Technical requirements** + +### **6.1 Appearance and structure** + +An RCD is mechanical switching device, which breaks the main circuit current by opening the switch contacts when the residual current reaches or exceeds a predetermined value. + +The device is equipped with a power disconnect mechanical indication. The RCD surface shall be even, clean, uniform in colour, and free from scratches, cracks and deformation. All fastening parts shall be firmly attached. All product labels shall be intact, clear and readable. + +The test button should be functional, see clause 6.8. + +RCDs' operational characteristics shall not be verified by any external loads except for the special equipment designed for verifying residual operation current levels. + +In multi-pole RCDs the moving contacts on all poles shall be mechanically connected to enable simultaneous breaking and closing manually or automatically except for switched neutral poles (if any). + +RCDs shall be trip-free and give a reliable indication of switch open and closed conditions. + +If indicator lights are used, they should be clearly visible when RCDs are in the closed position. Indicator lights shall not be the only method indicating the closed position. + +### **6.2 Enclosure requirement** + +#### **6.2.1 Protection against electric shock** + +RCDs' structure shall ensure its electrified parts are inaccessible after they are installed and wired correctly. + +RCDs' enclosure protection degree shall meet IP2X as specified in [IEC 60529]. + +#### 6.2.2 Enclosure fire risks + +Enclosure insulation components shall be non-flammable or self-extinguishing. + +### 6.3 Dielectric properties + +RCD insulation shall have adequate dielectric properties. + +The DC high voltage generated from normal circuit insulation tests shall not damage the control circuit connected to the main circuit after RCDs are installed. + +### 6.4 Temperature rise + +The temperature rise of the accessible RCD parts shall not exceed the limits specified in Table 1. RCDs shall not suffer damage influencing their functions and safety use. + +**Table 1 – Limits of temperature rise (based on [IEC 61008-1])** + +| Parts | Temperature rise / K | +|-----------------------------------------------------------------------------------------------------------------------------------------------------|----------------------| +| Terminals connecting outer conductors | 60 | +| Outer accessible parts during manual operation of RCDs including operating parts of insulation materials and insulated metal parts connecting poles | 40 | +| Outer metal parts of operating components | 25 | +| Other outer parts including the surface of RCDs directly in contact with mounting surfaces | 60 | + +Ambient air temperature: the temperature rise limits listed in Table 1 are applicable only if the ambient air temperature is kept at the range of normal working conditions. + +## 6.5 Operating characteristics + +The values required in this clause may vary depending on national requirements and laws and regulations. + +#### 6.5.1 Rated residual operating current ( $I_{\Delta N}$ ) + +The residual operating current value specified by manufacturers has preferred values of 0.006 A, 0.01 A, 0.03 A, 0.1 A, 0.3 A and 0.5 A. The levels of 0.03 A and below are intended to protect users from hazardous electric shock. + +#### 6.5.2 Rated residual non-operating current ( $I_{\Delta NO}$ ) + +The residual non-operating current value specified by manufacturers, has a preferred value of 50% of the rated residual operating current ( $0.5 I_{\Delta N}$ ). + +#### 6.5.3 Rated make and break capacity ( $I_M$ ) + +This parameter refers to the rated connecting/breaking capacity of RCDs with short-circuit protection. RCDs shall conform to the requirements of [IEC 60898-2] when the parts perform main circuit making/breaking functions with circuit breakers used for household and similar installations; RCDs shall conform to the requirements of [IEC 60947-2] when the parts perform main circuit making/breaking functions using low-voltage circuit breakers. + +Table 2 gives the minimum values of the rated making/ breaking current capability of RCDs without over-current protection. Table 3 gives corresponding power factors. + +**Table 2 – Minimum values of short-circuit test current (based on [IEC 61008-1])** + +| $I_N$ A | Prospective current for $I_M$ , $I_{\Delta M}$ , $I_{NC}$ , $I_{\Delta C}$ tests A | +|----------------------|------------------------------------------------------------------------------------| +| $I_N \leq 10$ | 300 | +| $10 < I_N \leq 50$ | 500 | +| $50 < I_N \leq 100$ | 1000 | +| $100 < I_N \leq 150$ | 1500 | +| $150 < I_N \leq 200$ | 2000 | + +**Table 3 – Power factors of short-circuit tests** + +| Short-circuit current $I_C$ , A | Power factor | +|---------------------------------|--------------| +| $I_C \leq 500$ | 1 | +| $500 < I_C \leq 1500$ | 0.95 | +| $1500 < I_C \leq 3000$ | 0.9 | + +#### **6.5.4 Rated residual making/breaking capacity ( $I_{\Delta M}$ )** + +Refer to Table 2 for the minimum values of rated residual making/breaking capacity and Table 3 for corresponding power factors. + +#### **6.5.5 Rated conditional short-circuit current ( $I_{NC}$ )** + +Refer to Table 2 for the minimum values of rated conditional short-circuit current and Table 3 for corresponding power factors. + +#### **6.5.6 Rated conditional residual short-circuit current ( $I_{\Delta C}$ )** + +Refer to Table 2 for the minimum values of rated conditional residual short-circuit current and Table 3 for corresponding power factors. + +#### **6.5.7 Break time** + +Table 4 gives the maximum break time of RCDs for protection against indirect contact. + +**Table 4 – Maximum break time of RCDs for protection against indirect contact** + +| $I_{\Delta M}$
A | $I_N$
A | Maximum break time, s | | | +|---------------------|---------------------------------------------------------------------------|-----------------------|-----------------|-----------------| +| | | $I_{\Delta M}$ | $2I_{\Delta M}$ | $5I_{\Delta M}$ | +| $I > 0.03$ | Any value | 0.2 | 0.1 | 0.04 | +| | $\geq 40$ (only applicable to RCDs assembled with independent components) | 0.2 | - | 0.15 | + +Table 5 gives the maximum break time of RCDs for direct contact protection. + +**Table 5 – Maximum break time of RCDs for protection against direct contact** + +| $I_{\Delta M}$
A | $I_N$
A | Maximum break time, s | | +|---------------------|------------|-----------------------|-----------------| +| | | $I_{\Delta M}$ | $5I_{\Delta M}$ | +| $\leq 0.03$ | Any value | 0.1 | 0.04 | + +#### 6.5.8 Delay operating time + +For time delay operating characteristics, the preferred values of delay time are 0.2 s, 0.4 s, 0.8 s, 1 s, 1.5 s and 2 s. Time delay characteristics are only applicable to RCDs for indirect contact protection. This term does not apply to the products without any time delay operating characteristics. + +### 6.6 Mechanical and electrical life + +RCDs shall be able to withstand the number operations specified in Table 6 in which every operating cycle includes one time of connecting and one time of breaking. + +**Table 6 – Operating cycle times** + +| Rated current $I_n$ | Operating cycle times | Including | | +|---------------------|-----------------------|--------------------|--------------------| +| | | On-load operations | No-load operations | +| $I_n \leq 25$ A | 4000 | 2000 | 2000 | +| $I_n > 25$ A | 3000 | 2000 | 1000 | + +### 6.7 Short-circuit current performance + +RCDs shall be able to carry out the specified number of short-circuit operations. Short-circuit operations shall not bring danger to any operator or form flashover among electrified conductive parts or between electrified conductive parts and earthing bonding parts. + +### 6.8 Test function of the device + +The RCD shall incorporate a test function and be equipped with a test load to simulate an operate residual current level to do scheduled tests on the operating capacity of the RCD. + +NOTE – A test device is used to check the trip function, but not to verify the validity of the function on the basis of rated residual operating current and break time. + +At rated voltage, the residual current flowing in the test load shall not exceed 2.5 times that of the residual current equal to $I_{\Delta N}$ flowing through any main circuit of the protective device. If an RCD has more than one residual operating current setting, the lowest designed value shall be adopted. + +Upon operating a test device, the protected conductor shall not be electrified. When an RCD is in the open position in normal use, the load side shall not supply power to a test load. + +Test loads are not designed for breaking operation. Therefore, they are not to be used for routine disconnection. + +### 6.9 Technical requirements for RCD functionally dependent on line voltage + +RCDs are functionally dependent on the AC line voltage and shall work properly at any line voltage between 0.85 to 1.1 times the rated voltage. Under such conditions, multi-pole RCDs' all currents shall be supplied by phase lines and neutral lines (if any) of power sources. + +At abnormal line voltage, RCDs have two operating functions of opening and closing main circuits. + +### 6.10 RCD working conditions upon over current of main circuits + +RCDs without overcurrent protection shall not operate under specified overcurrent conditions. For overcurrent protected RCDs, use [IEC 60898-2] or [IEC 60947-2] according to relevant product standards. + +### **6.11 RCD performance with surge current** + +RCDs shall have sufficient resistance to surge current to earth when operating with a capacitive load, or in the event of a device flashover. Time delay RCDs shall have sufficient capacity to prevent a fault trip in the event of a surge current to earth due to flashover. + +No fault operation shall occur when 1.2/50–8/20 combination wave, 2 kV is applied to power lines (L-N). A sample shall work normally without any damage when 1.2/50, 4 kV surge voltage is applied to power lines (L-N). + +A sample shall work normally without any damage when an 8/20, 20 kA lightning current passes through the RCD L to N, when a surge protective device is installed. The device shall be able to operate and to open the circuit, in the event of short-circuit condition. + +### **6.12 Technical requirements for automatic-reclosing devices** + +#### **6.12.1 Automatic-reclosing devices without residual current detection function** + +If the RCDs do not have electric residual current detection function after the opening, the RCDs automatically reclose typically once after 20 s to 60 s of the opening; if this is not successful, the devices reclose for a second time typically after a 15-minute delay; if this is still not successful, the devices reclose for a third time typically after another 15-minute delay. If not successful, no further reclosing is allowed. + +Successful reclosing means that the device shall stay closed for typically 5 s after it recloses. + +When an RCD trips, the automatic recloser will check the circuit where the RCD is installed to avoid safety problems where residual current still exists after the RCD is reclosed. + +#### **6.12.2 Automatic-reclosing devices with electric residual current detection function** + +After automatic-reclosing devices open, the requirements on the residual current detection functions are as follows: 1) no further reclosing is allowed after 3 unsuccessful reclosing attempts, typically within 1 minute. 2) testing voltage is $DC \leq 24\text{ V}$ or AC typical value $\leq 17\text{ V}$ . + +### **6.13 Environmental adaption** + +Operating environmental conditions: + +Normal range: $-5^{\circ}\text{C} \sim +40^{\circ}\text{C}$ + +Extended range: $-40^{\circ}\text{C} \sim +70^{\circ}\text{C}$ + +Humidity: 5% to 95% + +Atmospheric pressure: 70 kPa ~ 106 kPa. + +### **6.14 Safety warning** + +To remind skilled persons of the potential electric shock risk in the insulation case, the following warning sign and language shall be required to be placed on the equipment case: + +IEC 60417-6042 + +"WARNING " or equivalent word or text, and + +"HIGH TOUCH CURRENT" or equivalent text + +"Automatic-reclosing power devices" or equivalent text + +# Annex A + +## RCDAs with electric residual current detection function + +(This annex forms an integral part of this Recommendation.) + +## A.1 Technical rationale + +When an RCD trips, the automatic recloser will check the circuit where the RCD is installed to avoid safety problems where residual current still exists after the RCD is reclosed. + +Figure A.1-1 and Figure A.1-2 show the leakage fault detection circuit separately, representing single-phase and three-phase main power. + +The detecting signal passes through grounding, transformer and neutral line. The detecting circuit is installed on the output of an RCD phase and neutral line (a, b, c, n) respectively. Residual current detecting becomes a loop after checking the phase line, PE line, grounding resistance Re1 and Re2, the neutral line in the transformer and the detection circuit. The PE wire of the detection circuit does not need to connect to the equipment enclosure. The voltage of the detection circuit is 24 V d.c. + +![Figure A.1-1: Schematic diagram of a single-phase residual current detection circuit. The diagram shows three phase lines (L1, L2, L3) and a neutral line (N) entering from the top. A grounding resistor Re1 is connected between the neutral line and ground. A dotted line encloses the detection circuit, which includes a 'Detecting power supply' and a 'Detecting control' block. The power supply has terminals 'a' and 'b' connected to the phase and neutral lines respectively. The control block is connected to the power supply. A phase line (L1) is shown with a switch and a ground fault symbol (circle with a dot). The PE line is connected to the control block and to a grounding resistor Re2 via a PE terminal. The diagram is labeled K.135(18)_FA.1-1.](16c1175b5f05a4b55e6d396fc51b15b3_img.jpg) + +K.135(18)\_FA.1-1 + +Figure A.1-1: Schematic diagram of a single-phase residual current detection circuit. The diagram shows three phase lines (L1, L2, L3) and a neutral line (N) entering from the top. A grounding resistor Re1 is connected between the neutral line and ground. A dotted line encloses the detection circuit, which includes a 'Detecting power supply' and a 'Detecting control' block. The power supply has terminals 'a' and 'b' connected to the phase and neutral lines respectively. The control block is connected to the power supply. A phase line (L1) is shown with a switch and a ground fault symbol (circle with a dot). The PE line is connected to the control block and to a grounding resistor Re2 via a PE terminal. The diagram is labeled K.135(18)\_FA.1-1. + +Figure A.1-1 – Dotted line represents single-phase residual current detection circuit + +![Schematic diagram of a 3-phase residual current detection circuit. The diagram shows three phase lines (L1, L2, L3) and a neutral line (N) entering a device enclosure. Inside, a 'Detecting power supply' is connected to phases a, b, c, and N. A 'Detecting control' unit is connected to the power supply. A dotted line represents the residual current detection circuit, which loops from the power supply, through the device enclosure, and to the PE (Protective Earth) line. The PE line is connected to an earth electrode (Re2). Another earth electrode (Re1) is shown connected to the neutral line (N) outside the enclosure. The diagram is labeled K.135(18)_FA.1-2.](33ed1f9b27c7c21c797aa928b0f06851_img.jpg) + +Schematic diagram of a 3-phase residual current detection circuit. The diagram shows three phase lines (L1, L2, L3) and a neutral line (N) entering a device enclosure. Inside, a 'Detecting power supply' is connected to phases a, b, c, and N. A 'Detecting control' unit is connected to the power supply. A dotted line represents the residual current detection circuit, which loops from the power supply, through the device enclosure, and to the PE (Protective Earth) line. The PE line is connected to an earth electrode (Re2). Another earth electrode (Re1) is shown connected to the neutral line (N) outside the enclosure. The diagram is labeled K.135(18)\_FA.1-2. + +**Figure A.1-2 – Dotted line represents 3-phase residual current detection circuit** + +Figure A.1-3 and Figure A.1-4 show reclosing devices for residual current detection. + +The detecting signal passes through the device enclosure. The residual current detection becomes a loop after checking the phase line, the device enclosure and the PE line. The PE wire of the detection circuit needs to connect to the equipment enclosure. The voltage of the detection circuit is 24 V d.c. + +![Circuit diagram for single-phase residual current detection. It shows four input lines: L1, L2, L3, and N. L1, L2, and L3 have inductor symbols. A ground connection with resistance Re1 is on the left. A switch symbol is on the N line. A 'Detecting power supply' block has terminals 'a' and 'b'. A 'Detecting control' block is connected to it. A dotted line encloses the 'Detecting power supply', 'Detecting control', and a switch symbol with terminals 'a' and 'b'. This dotted area is connected to a PE (protective earth) line. The PE line connects to a ground connection with resistance Re2. The diagram is labeled K.135(18)_FA.1-3.](fa859e4e468bfb2710a94527f2c504af_img.jpg) + +Circuit diagram for single-phase residual current detection. It shows four input lines: L1, L2, L3, and N. L1, L2, and L3 have inductor symbols. A ground connection with resistance Re1 is on the left. A switch symbol is on the N line. A 'Detecting power supply' block has terminals 'a' and 'b'. A 'Detecting control' block is connected to it. A dotted line encloses the 'Detecting power supply', 'Detecting control', and a switch symbol with terminals 'a' and 'b'. This dotted area is connected to a PE (protective earth) line. The PE line connects to a ground connection with resistance Re2. The diagram is labeled K.135(18)\_FA.1-3. + +Figure A.1-3 – Dotted line represents single-phase residual current detection circuit + +![Circuit diagram for 3-phase residual current detection. It shows four input lines: L1, L2, L3, and N. L1, L2, and L3 have inductor symbols. A ground connection with resistance Re1 is on the left. A switch symbol is on the N line. A 'Detecting power supply' block has terminals 'a', 'b', 'c', and 'N'. A 'Detecting control' block is connected to it. A dotted line encloses the 'Detecting power supply', 'Detecting control', and a switch symbol with terminals 'a', 'b', 'c', and 'n'. This dotted area is connected to a PE (protective earth) line. The PE line connects to a ground connection with resistance Re2. The diagram is labeled K.135(18)_FA.1-4.](0f985b39edc1d52ba3600c438bc8f0a5_img.jpg) + +Circuit diagram for 3-phase residual current detection. It shows four input lines: L1, L2, L3, and N. L1, L2, and L3 have inductor symbols. A ground connection with resistance Re1 is on the left. A switch symbol is on the N line. A 'Detecting power supply' block has terminals 'a', 'b', 'c', and 'N'. A 'Detecting control' block is connected to it. A dotted line encloses the 'Detecting power supply', 'Detecting control', and a switch symbol with terminals 'a', 'b', 'c', and 'n'. This dotted area is connected to a PE (protective earth) line. The PE line connects to a ground connection with resistance Re2. The diagram is labeled K.135(18)\_FA.1-4. + +Figure A.1-4 – Dotted line represents 3-phase residual current detection circuit + +## Bibliography + +- [b-IEC 60050-442] IEC 60050-442 (1998), *International Electrotechnical Vocabulary – Part 442: Electrical accessories*. +- [b-IEC 60755] IEC 60755 (2017), *General safety requirements for residual current operated protective devices*. +- [b-IEC 60898-1] IEC 60898-1 (2015), *Electrical accessories – Circuit-breakers for overcurrent protection for household and similar installations – Part 1: Circuit-breakers for a.c. operation*. +- [b-IEC 61557-6] IEC 61557-6 (2007), *Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. – Equipment for testing, measuring or monitoring of protective measures – Part 6: Effectiveness of residual current devices (RCD) in TT, TN and IT systems*. +- [b-IEC 61936-1] IEC 61936-1 (2014), *Power installations exceeding 1 kV a.c. – Part 1: Common rules*. +- [b-IEC 62368-1] IEC 62368-1 (2018), *Audio/video, information and communication technology equipment – Part 1: Safety requirements*. +- [b-IEC 62752] IEC 62752 (2016), *In-cable control and protection device for mode 2 charging of electric road vehicles (IC-CPD)*. +- [b-IEC 62873-2] IEC 62873-2 (2016), *Residual current operated circuit-breakers for household and similar use – Part 2: Residual current devices (RCDs) – Vocabulary*. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.147-202507-I_PDF-E/raw.md b/marked/K/T-REC-K.147-202507-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..8780856aa113cdaf163d49e5606dc3c8b0c67638 --- /dev/null +++ b/marked/K/T-REC-K.147-202507-I_PDF-E/raw.md @@ -0,0 +1,1452 @@ + + +# Recommendation **ITU-T K.147 (07/2025)** + +SERIES K: Protection against interference + +--- + +# **Protection of digital ports connected to balanced pairs of conductors** + +![ITU logo](390120de4fe440c42fea8154fcaad334_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with white lines representing latitude and longitude, and the letters 'ITU' in a bold, blue, sans-serif font overlaid on the globe. + +ITU logo + + + +# Recommendation ITU-T K.147 + +# Protection of digital ports connected to balanced pairs of conductors + +## Summary + +Recommendation ITU-T K.147 considers the overvoltage and overcurrent protection of information technology equipment including IEEE 802.3 Ethernet. This Recommendation describes how surges are coupled into the system and what surge mitigation measures are used, considering the differences in implementations and network configurations. Furthermore, it contains the different surge and power fault test circuit approaches and conditions under which the specified tests are applied. + +Networked equipment can be subject to overvoltage and overcurrent transients. Both data and powering services should be resistant to expected environmental transients. Where equipment has multiple independent ports, such as central hubs, switches, or repeaters, then testing for inter-port resistibility is required. + +Resistibility testing needs to identify lightning transients coupled into a network by magnetic induction, earth potential rise, resistive coupling, and transient coupling by a voltage-limiting operation of surge protective functions or flashover. Voltage limitation may convert common-mode surges into differential-mode surges in the signal path. Depending on local installation practices, it is also possible for alternating current mains power faults to couple into the network, which can necessitate the use of overcurrent protection. + +## History\* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|---------------------------|------------|-------------|--------------------| +| 1.0 | ITU-T K.147 | 2020-06-29 | 5 | 11.1002/1000/14300 | +| 1.1 | ITU-T K.147 (2020) Cor. 1 | 2021-01-06 | 5 | 11.1002/1000/14575 | +| 2.0 | ITU-T K.147 | 2022-01-13 | 5 | 11.1002/1000/14726 | +| 3.0 | ITU-T K.147 | 2023-07-22 | 5 | 11.1002/1000/15181 | +| 4.0 | ITU-T K.147 | 2025-07-29 | 5 | 11.1002/1000/16426 | + +## Keywords + +Configurations, Ethernet, K recommendation applicability, single pair, single pair Ethernet (SPE), surge coupling, test circuits, test levels, variants. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, and information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2025 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|------|-------------------------------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 3.1 | Terms defined elsewhere ..... | 1 | +| 3.2 | Terms defined in this Recommendation..... | 2 | +| 4 | Abbreviations and acronyms ..... | 3 | +| 5 | Conventions ..... | 3 | +| 6 | Overview..... | 3 | +| 6.1 | General ..... | 3 | +| 6.2 | Network power delivery ..... | 4 | +| 6.3 | Twisted-pair data link and surge protector capacitance ..... | 4 | +| 6.4 | Twisted pair powering usage..... | 5 | +| 6.5 | Link insulation..... | 6 | +| 6.6 | Summary of link conductor usage..... | 6 | +| 7 | Link voltage, current and resistance values..... | 7 | +| 8 | Surges on network systems..... | 7 | +| 8.1 | Surge coupling mechanisms ..... | 7 | +| 8.2 | Direct coupling – permanent ..... | 7 | +| 8.3 | Direct coupling – transient ..... | 8 | +| 8.4 | Magnetic coupling ..... | 11 | +| 8.5 | Electric and electromagnetic coupling ..... | 12 | +| 8.6 | Surge resistibility design approaches ..... | 13 | +| 9 | [ITU-T K.44] and [ITU-T K.117] test circuits ..... | 13 | +| 9.1 | Test circuit overview ..... | 13 | +| 9.2 | Power fault resistibility..... | 16 | +| 9.3 | RP link..... | 16 | +| | Annex A – Ethernet surge test circuits based on ITU-T K-series Recommendations..... | 17 | +| A.1 | Introduction ..... | 17 | +| A.2 | Ethernet port testing ..... | 17 | +| A.3 | Testing of XDSL ports ..... | 30 | +| | Appendix I – Examples of Ethernet twisted pair DC power feeds ..... | 40 | +| I.1 | Introduction ..... | 40 | +| I.2 | Powering over one twisted pair ..... | 40 | +| I.3 | Powering over two twisted pairs ..... | 41 | +| I.4 | Powering over four twisted pairs..... | 43 | +| | Appendix II – Networking evolution..... | 45 | +| II.1 | General ..... | 45 | + +| | Page | +|--------------------|------| +| II.2 Testing ..... | 45 | +| Bibliography..... | 46 | + +# Recommendation ITU-T K.147 + +# Protection of digital ports connected to balanced pairs of conductors + +# 1 Scope + +This Recommendation describes the overvoltage and overcurrent protection of information technology equipment with digital port including Ethernet port regarding the testing found in [ITU-T K.20], [ITU-T K.21], [ITU-T K.44], [ITU-T K.45] and [ITU-T K.117]. Topics covered are: + +- overvoltage and overcurrent events coupling into the network system depending on + - implementation condition, + - system configuration, + - powering condition (data only or provision of network powering) and + - link insulation; +- lightning surge resistibility test circuit approaches; +- power fault resistibility test circuit approaches; +- resistibility test circuit applicability to [ITU-T K.20], [ITU-T K.21], [ITU-T K.44], [ITU-T K.45] and [ITU-T K.117]. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.20] Recommendation ITU-T K.20 (2022), *Resistibility of telecommunication equipment installed in a telecommunication centre to overvoltages and overcurrents.* +- [ITU-T K.21] Recommendation ITU-T K.21 (2022), *Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents.* +- [ITU-T K.44] Recommendation ITU-T K.44 (2019), *Resistibility tests for telecommunication equipment exposed to overvoltages and overcurrents – Basic Recommendation.* +- [ITU-T K.45] Recommendation ITU-T K.45 (2022), *Resistibility of telecommunication equipment installed in the access and trunk networks to overvoltages and overcurrents.* +- [ITU-T K.117] Recommendation ITU-T K.117 (2016), *Primary protector parameters for the surge protection of equipment Ethernet ports.* + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 balanced cable** [b-ISO/IEC 11801-1]: Cable consisting of one or more metallic symmetrical cable elements (twisted pairs or quads). + +**3.1.2 cable element** [b-ISO/IEC 11801-1]: Smallest construction unit in a cable. + +NOTE 1 – Examples are a balanced pair, quad, single fibre, or coaxial pair. + +NOTE 2 – A cable element may have a screen. + +**3.1.3 cabling** [b-ISO/IEC 11801-1]: System of telecommunications cables, cords and connecting hardware that supports the connection of information technology equipment. + +**3.1.4 link** [b-ISO/IEC 11801-1]: Transmission path between two cabling system interfaces, including the connections at each end. + +**3.1.5 network powered device (NPD)** [b-ISO/IEC TR 15044]: Device that derives its power from the network. + +**3.1.6 remote powering (RP)** [b-ETSI EN 302 099]: Power feeding of a telecommunications equipment by a remote power circuit. + +NOTE – Such a circuit consists of a remote power unit, distribution wiring, and fed receivers. + +**3.1.7 twisted pair** [b-ISO/IEC 11801-1]: Cable element that consists of two insulated conductors twisted together in a determined fashion to form a balanced transmission line. + +## **3.2 Terms defined in this Recommendation** + +This Recommendation defines the following terms: + +**3.2.1 network power source equipment (NPSE)**: Equipment that provides power to network, specifically to power NPDs. + +**3.2.2 injector network power source equipment**: A network power source equipment (NPSE) that is not integrated into an endpoint (or data terminal equipment (DTE)) but is located within a link, providing power to the link section that connects to a network-powered device (NPD). + +NOTE 1 – Injector network power source equipment is often simply called "injector". + +NOTE 2 – The injector can be a single item or consist of a coupling network with a separate power supply. + +NOTE 3 – The term injector is not used in IEEE Std. 802.3. These items are called "midspans" in IEEE Std. 802.3. The midspans are required to perform detection before applying power. The term injector is used by the industry to identify NPSEs that do not perform detection and thus blindly apply power. + +**3.2.3 phantom powering**: A method that provides power to a device using signalling conductors where the power and signals are multiplexed onto the same conductors. + +NOTE 1 – In this recommendation, the term "phantom powering" is used for the meaning of "Transmission of electrical power from network power source equipment (NPSE) to a network-powered device (NPD) using two balanced data pairs; with the power being applied to the pair balance nodes at the NPSE link end and extracted from the pair balance nodes at the NPD link end". + +NOTE 2 – The data pair balance node is usually the centre tap of the data pair isolating transformer. + +NOTE 3 – When all four pairs of an Ethernet link are used, double phantom powering occurs if the two power transmissions are kept separate. Single phantom powering is considered to occur when the NPD combines the two power transmissions into one. + +**3.2.4 power over Ethernet (PoE)**: Link phantom powering of a network-powered device using two or four balanced data pairs connected to power source equipment. + +**3.2.5 single pair Ethernet (SPE)**: Ethernet physical layer specification associated to a single balanced pair of conductors applied to the tests proposal of this Recommendation. + +**3.2.6 single pair power over Ethernet (SPoE); power over data line (PoDL)**: Link powering of a network-powered device using a balanced data pair connected to power source equipment. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|-----------------------------------------------------| +| AC | Alternating Current | +| AE | Auxiliary Equipment | +| AT | Ampere-Turn | +| DC | Direct Current | +| DTE | Data Terminal Equipment | +| EMC | Electromagnetic Compatibility | +| EPR | Earth Potential Rise | +| EUT | Equipment Under Test | +| GDT | Gas Discharge Tube | +| LPS | Lightning Protection System | +| NCD | Network Coupler-Decoupler | +| NPD | Network-Powered Device | +| PD | Power Delivery | +| PE | Protective Earth | +| PoDL | Power over Data Line | +| PoE | Power over Ethernet | +| NPSE | Network Power Source Equipment | +| RP | Remote Powering | +| SPD | Surge Protective Device | +| SPE | Single Pair Ethernet | +| SPICE | Simulation Program with Integrated Circuit Emphasis | +| SPoE | Single pair Power over Ethernet | +| SW | Switch | +| USB | Universal Serial Bus | +| XDSL | Any type of Digital Subscriber Line | + +# 5 Conventions + +None. + +# 6 Overview + +## 6.1 General + +The use of an equipment link to deliver power and data simplifies system implementation in automotive, industrial, commercial, healthcare, and domestic environments. This Recommendation discusses network configurations where data and direct current (DC) powering can take place over an inter-equipment link. Topics covered are power delivery (PD) levels, system transient overvoltages, and possible protective measures against system transients. + +Note that single-pair Ethernet (SPE) deployment is currently minimal, and there is an absence of field data to support resistibility requirements. As a result, SPE content in this Recommendation is derived from specifications found in [b-IEEE 802.3]. + +## 6.2 Network power delivery + +Figure 1 shows generic examples of network configurations where data and power are transferred over a link. There are three main elements in such systems: hardware capable of supplying DC power, called network power source equipment (NPSE); an NPD; and a twisted pair link section connecting the NPSE to the NPD. The upper part of Figure 1 shows an NPSE directly connected to an NPD. The middle part of Figure 1 shows how a system based on pure data can be converted to one based on PoE by adding a power injector NPSE. The lower part of Figure 1 shows how a combination of an NPD and NPSE can be used to daisy-chain multiple pieces of equipment to extend the reach or to have several NPDs or both. + +Examples of two, four and single balanced twisted-pair systems can be found in clauses 33, 145 and 104, respectively, of [b-IEEE 802.3], along with their Ethernet configurations. + +![Figure 1: Generic examples of network configurations where data and power are transferred over a link. The diagram illustrates three scenarios: 1) A direct connection between a Data function and power source equipment (NPSE) and a Data function and Network powered device (NPD) via a twisted-pair link with RP. 2) A system where a Data function only device is connected to an Injector NPSE, which is then connected to an NPD via twisted-pair links. 3) A daisy-chained configuration where an NPSE is connected to a combination of an NPD and NPSE (Daisy chained equipment), which is then connected to an NPD via twisted-pair links with RP.](daa4a6fa7e2ba1954258f86b4928eb32_img.jpg) + +The diagram illustrates three generic network configurations for power delivery over twisted-pair links: + +- Top configuration:** A **Data function and power source equipment (NPSE)** (containing 'Data' and 'Power source' blocks) is connected via a **Twisted-pair link with RP** to a **Data function and Network powered device (NPD)** (containing 'Data' and 'Power conversion' blocks). +- Middle configuration:** A **Data function only** device (containing 'Data') is connected via a **Twisted-pair link data only** to an **Injector NPSE** (containing 'Data' and 'Power source'). This is then connected via a **Twisted-pair link with RP** to an **Data function and Network powered device (NPD)** (containing 'Data' and 'Power conversion'). +- Bottom configuration:** A **Data function and network power source equipment (NPSE)** (containing 'Data' and 'Power source') is connected via a **Twisted-pair link with RP** to a **Daisy chained equipment (Data, NPD + NPSE)**. This equipment contains an **NPD** (Data, Power conversion) and an **NPSE** (Data, Power source) connected by a dashed line. This is then connected via a **Twisted-pair link with RP** to another **Data function and Network powered device (NPD)** (containing 'Data' and 'Power conversion'). + +K.147(23)\_F01 + +Figure 1: Generic examples of network configurations where data and power are transferred over a link. The diagram illustrates three scenarios: 1) A direct connection between a Data function and power source equipment (NPSE) and a Data function and Network powered device (NPD) via a twisted-pair link with RP. 2) A system where a Data function only device is connected to an Injector NPSE, which is then connected to an NPD via twisted-pair links. 3) A daisy-chained configuration where an NPSE is connected to a combination of an NPD and NPSE (Daisy chained equipment), which is then connected to an NPD via twisted-pair links with RP. + +**Figure 1 – Generic examples of network configurations where data and power are transferred over a link** + +## 6.3 Twisted-pair data link and surge protector capacitance + +A twisted pair link can carry the data by one, two or four twisted pairs, as shown in Figure 2. At high data rates, the protector capacitance loading becomes important both in value and in its possible variation with voltage. Protector capacitance values are covered in [b-ITU-T K.12], [b-ITU-T K.96], [b-ITU-T K.99], [b-ITU-T K.103] and [b-ITU-T K.129]. + +![Figure 2: Twisted pair link data transfer diagrams showing single, two, and four pair configurations.](cfef993dcc8fb513de79eb1f93cf26ae_img.jpg) + +Figure 2 consists of three diagrams illustrating twisted pair link data transfer. The first diagram, titled 'Single pair data link', shows a single twisted pair with two isolating transformers at each end. The second diagram, titled 'Two pair data link', shows two twisted pairs with two isolating transformers at each end. The third diagram, titled 'Four pair data link', shows four twisted pairs with two isolating transformers at each end. Each diagram includes labels for the twisted pairs (1, 2, 3, 4, 5, 6, 7, 8) and 'Data pair' labels at the ends. The reference 'K.147(22)\_F02' is shown at the bottom right. + +Figure 2: Twisted pair link data transfer diagrams showing single, two, and four pair configurations. + +**Figure 2 – Twisted pair link data transfer** + +Protecting a data transceiver against differential surges is typically done on the isolated secondary side of the transformer by clamping diodes to the transceiver supply rails or by low-capacitance punch-through diodes, as detailed in [b-ITU-T K.96]. Typically, the protection threshold voltage levels are between 5 V and 10 V. If the differential surge protection is applied on the link side of the transformer, higher current capability punch-through diodes are required. In the single twisted-pair case, with RP, the protection should be applied directly to the data transceiver as the link overvoltage protection is likely to have a threshold voltage above 60 V. + +## 6.4 Twisted pair powering usage + +For single twisted-pair links, the RP voltage is differentially applied to the single twisted pair, just as the data is. Figure 3 shows an example of such a configuration. Data is introduced and extracted from the link by means of alternating current (AC) coupled isolating transformers. Powering is introduced and extracted from the link by means of a differential-mode choke, which prevents the power source and power conversion functions from shunting the data signal. + +![Figure 3: Example of single twisted-pair with remote powering using inductive filtering diagram.](7e670a2b556b53ea9002dfff3a420e08_img.jpg) + +Figure 3 is a block diagram showing a 'Power source equipment (PSE)' on the left and a 'Network powered device (NPD)' on the right, connected by a 'Single twisted-pair link with RP'. The PSE contains a 'Power source' connected to a 'Differential mode choke', which is connected to the twisted pair. The NPD contains a 'Differential mode choke' connected to the twisted pair, which is then connected to a 'Power conversion' block. Both the PSE and NPD also contain a 'Data' block connected to the twisted pair via an isolating transformer. The reference 'K.147(23)\_F03' is shown at the bottom right. + +Figure 3: Example of single twisted-pair with remote powering using inductive filtering diagram. + +**Figure 3 – Example of single twisted-pair with remote powering using inductive filtering** + +NOTE – Other methods may vary, such as non-transformer methods for extracting the data signal. + +Protecting the power source and power conversion elements against differential surges is typically done with a PN diode, as detailed in [b-ITU-T K.96], as the maximum powering voltage is in the range of 18 V to 60 V. + +Phantom powering requires at least two independent metallic circuits. For more power, the phantom powering configuration can be duplicated by increasing the number of twisted pairs from two to four. Figure 4 shows a phantom powering arrangement. Current $I_1$ leaving the power source positive terminal enters the NPSE data 1 transformer centre tap and splits into currents of $0.5I_1$ in each twisted pair conductor. These currents recombine as $I_1$ in the NPD data 1 transformer that feeds the power conversion positive terminal. The negative power conversion terminal current return route is similar, feeding the NPD data 2 transformer centre tap. Further examples of different PoE configurations are shown in Figures I.3 to I.10. + +As the powering is applied differentially to the two data pairs, differential overvoltage protection should be applied between them. This protection can be applied between the link pairs or at the power source and power conversion functions. + +A conventional common-mode choke protecting data and power feeds should not be used in phantom powered systems, as the net DC of $I_1$ in any pair is likely to saturate the common-mode choke core. As the net DC of the two pairs is zero, a four-winding common-mode choke can be used. Two of the windings would be placed in data pair 1 and the other two in data pair 2. + +![Figure 4: Example of phantom powering. A circuit diagram showing Power Source Equipment (PSE) on the left and a Network Powered Device (NPD) on the right, connected by a Link with two balanced data pairs. In the PSE, a Power Source block's positive terminal connects to the center tap of Data 1 transformer, sending current I1 which splits into 0.5I1 per wire in Balanced data pair 1. These recombine at the NPD's Data 1 transformer center tap and flow into the positive terminal of a Power Conversion block. The return current I1 flows from the negative terminal of the Power Conversion block, through the center tap of the NPD's Data 2 transformer, splitting into 0.5I1 per wire in Balanced data pair 2, and finally recombining at the PSE's Data 2 transformer center tap to return to the Power Source negative terminal.](27b06ec9f42b5d727a2630f61a5f1861_img.jpg) + +``` + +graph LR + subgraph PSE [Power source equipment] + PS[Power source] + T1_PSE[Data 1 Transformer] + T2_PSE[Data 2 Transformer] + end + subgraph Link + DP1[Balanced data pair 1] + DP2[Balanced data pair 2] + end + subgraph NPD [Network powered device] + T1_NPD[Data 1 Transformer] + T2_NPD[Data 2 Transformer] + PC[Power conversion] + end + + PS -- "I1 (+)" --> T1_PSE + T1_PSE -- "0.5I1" --> DP1 + DP1 -- "0.5I1" --> T1_NPD + T1_NPD -- "I1" --> PC + PC -- "I1 (-)" --> T2_NPD + T2_NPD -- "0.5I1" --> DP2 + DP2 -- "0.5I1" --> T2_PSE + T2_PSE -- "I1" --> PS + +``` + +Figure 4: Example of phantom powering. A circuit diagram showing Power Source Equipment (PSE) on the left and a Network Powered Device (NPD) on the right, connected by a Link with two balanced data pairs. In the PSE, a Power Source block's positive terminal connects to the center tap of Data 1 transformer, sending current I1 which splits into 0.5I1 per wire in Balanced data pair 1. These recombine at the NPD's Data 1 transformer center tap and flow into the positive terminal of a Power Conversion block. The return current I1 flows from the negative terminal of the Power Conversion block, through the center tap of the NPD's Data 2 transformer, splitting into 0.5I1 per wire in Balanced data pair 2, and finally recombining at the PSE's Data 2 transformer center tap to return to the Power Source negative terminal. + +**Figure 4 – Example of phantom powering** + +## 6.5 Link insulation + +It is important that the insulation related to the link does not break down. The maximum link withstand voltage can be due to cabling, connectors, data transformers, electromagnetic compatibility (EMC) screen spacing and printed circuit board trace dimensioning. To prevent breakdown, a voltage limiter can be connected in shunt with the insulation. Using only a single shunt voltage limiter, rather than multiple voltage limiters from various circuit nodes, reduces the possibility of common-mode to differential-mode surge conversion. + +## 6.6 Summary of link conductor usage + +Figure 5 shows the various data and powering conductor allocations as discussed in clauses 6.1 to 6.5. For further information, see clauses 33, 104 and 145 of [b-IEEE 802.3]. + +![Figure 5: Summary of typical twisted-pair connector conductor remote powering (RP) usage. The diagram is divided into two parts. The top part, titled 'Single twisted-pair RP', shows a connector with pins 1 and 2 labeled 'RP connections' and a 'Screen' pin. The bottom part, titled '2 and 4 twisted-pair RP modes and connections', shows a connector with pins 1 through 8. Pins 1 and 2 are labeled 'Twisted-pair (1, 2) all data rates'. Pins 3 and 6 are labeled 'Twisted-pair (3, 6) all data rates'. Pins 4 and 5 are labeled 'Twisted-pair (4, 5) ≥ 1 Gb/s data'. Pins 7 and 8 are labeled 'Twisted-pair (7, 8) ≥ 1 Gb/s data'. A 'Cable screen (if present)' is indicated for pins 1, 2, 3, 6, 4, 5, 7, and 8. The diagram shows two modes: 'mode A' uses twisted pairs 1-2 and 3-6; 'mode B' uses twisted pairs 4-5 and 7-8. A vertical double-headed arrow on the right indicates that '1-2, 3-6, 4-5 and 7-8 Modes A + B 4 twisted-pairs' are available.](af7916c89a458fdab6c3f443217388ae_img.jpg) + +Figure 5: Summary of typical twisted-pair connector conductor remote powering (RP) usage. The diagram is divided into two parts. The top part, titled 'Single twisted-pair RP', shows a connector with pins 1 and 2 labeled 'RP connections' and a 'Screen' pin. The bottom part, titled '2 and 4 twisted-pair RP modes and connections', shows a connector with pins 1 through 8. Pins 1 and 2 are labeled 'Twisted-pair (1, 2) all data rates'. Pins 3 and 6 are labeled 'Twisted-pair (3, 6) all data rates'. Pins 4 and 5 are labeled 'Twisted-pair (4, 5) ≥ 1 Gb/s data'. Pins 7 and 8 are labeled 'Twisted-pair (7, 8) ≥ 1 Gb/s data'. A 'Cable screen (if present)' is indicated for pins 1, 2, 3, 6, 4, 5, 7, and 8. The diagram shows two modes: 'mode A' uses twisted pairs 1-2 and 3-6; 'mode B' uses twisted pairs 4-5 and 7-8. A vertical double-headed arrow on the right indicates that '1-2, 3-6, 4-5 and 7-8 Modes A + B 4 twisted-pairs' are available. + +**Figure 5 – Summary of typical twisted-pair connector conductor remote powering (RP) usage** + +# 7 Link voltage, current and resistance values + +For single, two and four balanced pair links, over the equipment or device microclimate temperature range, any series protection functions must not operate at the link maximum continuous current or, if not automatically resetting, during surge testing. The series protection function resistance should only be a small fraction of the link loop resistance to avoid reducing the configuration reach, with the resistance chosen based on the maximum value of the link loop resistance, 12.5 ohms. Over the equipment or device microclimate temperature range, any shunt voltage-limiting protective functions must have a minimum conduction threshold voltage above the NPSE maximum voltage. + +# 8 Surges on network systems + +## 8.1 Surge coupling mechanisms + +[b-ITU-T K.39] states that there are four main coupling mechanisms for surges to couple into networks and equipment: + +- direct coupling (permanent or transient); +- magnetic coupling; +- electric coupling; +- electromagnetic coupling. + +## 8.2 Direct coupling – permanent + +Resistive coupling may be a permanent coupling like differential earth potential rise (EPR), or transient coupling like the operation of a surge protective device (SPD) or a side flash. The use of inappropriate SPDs can often cause equipment failure through common- to differential-mode surge conversion, as outlined [ITU-T K.117]. + +Figure 6 depicts a lightning strike to uniform resistivity soil where the lightning current spreads out radially and a series of concentric (dashed) equipotential rings can be mapped. If two earth rods, A and B, are positioned on a strike radial and on different equipotential rings, there will be a difference + +in EPR between them. Equipment bonded to A and that to B will have a differential EPR between them and this is applied to any connecting link between A and B equipment. If the link has a cable screen, a high potential-equalizing current flows in the screen. + +![Figure 6 – Lightning EPR example. The figure consists of three parts. The top part is a plan view showing concentric dashed circles representing equipotential rings around a central lightning strike point. A radial line extends from the center through points A and B. The middle part is a graph of Earth potential rise versus distance from the strike. It shows a curve starting high at the strike and decaying. Point A is on the curve, and point B is further away. The vertical distance from the curve to point A is labeled 'Earth potential rise'. The vertical distance between points A and B is labeled 'A to B voltage difference'. A cable link is shown between A and B, with 'Cable link voltage stress' indicated. The bottom part is another graph of Earth potential rise versus distance from the strike. It shows a similar curve. Point A is on the curve, and point B is further away. The vertical distance from the curve to point A is labeled 'Earth potential rise'. The vertical distance between points A and B is labeled 'A to B voltage difference'. A cable link with a screen is shown between A and B. A current 'i' is shown flowing in the screen, with the text 'Screened cable bypasses current'.](0b8b087a7baa471015d3ffeaa43d9a6c_img.jpg) + +Figure 6 – Lightning EPR example. The figure consists of three parts. The top part is a plan view showing concentric dashed circles representing equipotential rings around a central lightning strike point. A radial line extends from the center through points A and B. The middle part is a graph of Earth potential rise versus distance from the strike. It shows a curve starting high at the strike and decaying. Point A is on the curve, and point B is further away. The vertical distance from the curve to point A is labeled 'Earth potential rise'. The vertical distance between points A and B is labeled 'A to B voltage difference'. A cable link is shown between A and B, with 'Cable link voltage stress' indicated. The bottom part is another graph of Earth potential rise versus distance from the strike. It shows a similar curve. Point A is on the curve, and point B is further away. The vertical distance from the curve to point A is labeled 'Earth potential rise'. The vertical distance between points A and B is labeled 'A to B voltage difference'. A cable link with a screen is shown between A and B. A current 'i' is shown flowing in the screen, with the text 'Screened cable bypasses current'. + +Figure 6 – Lightning EPR example + +## 8.3 Direct coupling – transient + +### 8.3.1 Voltage limiters + +The operation of equipment surge protective components or external SPDs can couple transients into a protected service or service transients can be injected into the equipotential bonding network causing localized voltage rise due to bonding conductor inductance. + +Voltage limiters are used to protect insulation from breakdown and components from failure. Voltage limitation must not operate under steady-state conditions. Depending on the voltage-limitation technology, temporary overvoltage size and duration, the voltage limiter may or may not operate. Under surge conditions, for fast- and slow-front surges, voltage limitation occurs. Should a power cross condition occur, the link conductors could have the local AC mains voltage applied to them. To prevent damaging high AC currents to earth, the voltage threshold of link-to-earth protection must be higher than the local AC mains peak voltage. ITU-T equipment Recommendations, such as [ITU-T K.21], verify this by measuring the link to earth insulation resistance at 500 V DC. The measured resistance must be equal to or greater than 2 M $\Omega$ . If the measured value is less than 2 M $\Omega$ , then an AC mains power cross test is then performed to identify any safety hazards. Figure 7 is a simplified version of a [b-IEC 60099-5] diagram illustrating how AC distribution equipment insulation withstands changes with time and how voltage limitation prevents insulation breakdown. + +![Figure 7: AC system overvoltage level, insulation withstand and voltage limitation variation with time. The graph plots Voltage level on the y-axis against Time duration of voltages on the x-axis. The x-axis is divided into four regions: Fast-front overvoltages (μs), Slow-front overvoltages (ms), Temporary overvoltages (s), and Operating voltage (Continuous). A blue stepped line represents 'Overvoltages', starting high and decreasing in steps. A red curve represents 'Insulation withstand', which decreases over time. A green curve represents 'Voltage limited by surge protection', which also decreases over time. A horizontal cyan line at the bottom represents 'Normal voltage'. The graph shows that the insulation withstand and voltage limitation curves are above the normal voltage line, and the overvoltage curve is above the insulation withstand curve.](71ab4df17511d75261da8d462d643b1a_img.jpg) + +Figure 7: AC system overvoltage level, insulation withstand and voltage limitation variation with time. The graph plots Voltage level on the y-axis against Time duration of voltages on the x-axis. The x-axis is divided into four regions: Fast-front overvoltages (μs), Slow-front overvoltages (ms), Temporary overvoltages (s), and Operating voltage (Continuous). A blue stepped line represents 'Overvoltages', starting high and decreasing in steps. A red curve represents 'Insulation withstand', which decreases over time. A green curve represents 'Voltage limited by surge protection', which also decreases over time. A horizontal cyan line at the bottom represents 'Normal voltage'. The graph shows that the insulation withstand and voltage limitation curves are above the normal voltage line, and the overvoltage curve is above the insulation withstand curve. + +K.147(25) + +**Figure 7 – AC system overvoltage level, insulation withstand and voltage limitation variation with time** + +Figure 8 shows three undesirable consequences of AC mains service SPD operation. If a large EPR occurs, the SPD can couple that surge onto the protected service as shown in Figure 8a. Figure 8b shows how current surges on the service are diverted by the SPD into the local earthing system causing local protective earth (PE) inductive surge voltages. Figure 8c, for three-wire (L1, L2 and N) single phase installations, common in Japan and the USA, shows how SPDs applied to one L-N pair can cause surge voltage differences between equipment connected to L1-N and L2-N. SPDs applied to communication services can cause similar events to the left- and centre-circuits. + +![Figure 8: Three diagrams illustrating SPD consequences. (a) SPD coupling of EPR voltage: Shows a lightning strike on a cable, with an EPR (Electrostatic Potential Rise) occurring. The SPD is connected between the L and N conductors and the earth. The EPR is coupled to the AC mains. (b) Injecting surge current into the local earthing system: Shows the SPD diverting surge current into the local earthing system, causing a local potential rise and wiring inductance. (c) Causing differential surge on three wire single phase mains: Shows a three-wire single phase installation with L1, L2, and N conductors. The SPD is connected between the L1 and N conductors. The surge current is diverted into the local earthing system, causing a differential surge between the L1-N and L2-N pairs.](75f0cb39f1cd165dfe4a6aa6c4d9388d_img.jpg) + +Figure 8: Three diagrams illustrating SPD consequences. (a) SPD coupling of EPR voltage: Shows a lightning strike on a cable, with an EPR (Electrostatic Potential Rise) occurring. The SPD is connected between the L and N conductors and the earth. The EPR is coupled to the AC mains. (b) Injecting surge current into the local earthing system: Shows the SPD diverting surge current into the local earthing system, causing a local potential rise and wiring inductance. (c) Causing differential surge on three wire single phase mains: Shows a three-wire single phase installation with L1, L2, and N conductors. The SPD is connected between the L1 and N conductors. The surge current is diverted into the local earthing system, causing a differential surge between the L1-N and L2-N pairs. + +K.147(25) + +**Figure 8 – a – SPD coupling of EPR voltage; b – injecting surge current into the local earthing system; c – causing differential surge on three wire single phase mains** + +When a common-mode surge occurs on cable conductors, asynchronous voltage limitation can result in the creation of a large differential surge. Figure 9 shows a circuit that produces common- to differential-mode conversion. Generator G is charged to 2 kV and produces a 5/75 voltage waveshape. Equal value resistors, R1 and R2, feed the common-mode surge to cable conductors A and B. Gas discharge tubes (GDTs), GDTA (520 V sparkover voltage) and GDTB (540 V sparkover + +voltage), limit the maximum conductor voltages. Resistor R3, between the conductors, represents the port termination and the mutual conductor coupling. + +![Circuit diagram showing two conductors, A and B, with various components. Conductor A is connected to a GDTA (520 V) and one end of resistor R3 (300 Ω). Conductor B is connected to a GDTB (540 V), one end of resistor R2 (150 Ω), and one end of resistor R1 (150 Ω). The other end of R3 is connected to Conductor B. The other end of R2 is connected to a voltage source G (2000 V, 5/75). The other end of R1 is connected to the junction of R2 and G. A label K.147(25) is at the bottom right.](5cab96b2d23174c25919840ecd50aa48_img.jpg) + +Circuit diagram showing two conductors, A and B, with various components. Conductor A is connected to a GDTA (520 V) and one end of resistor R3 (300 Ω). Conductor B is connected to a GDTB (540 V), one end of resistor R2 (150 Ω), and one end of resistor R1 (150 Ω). The other end of R3 is connected to Conductor B. The other end of R2 is connected to a voltage source G (2000 V, 5/75). The other end of R1 is connected to the junction of R2 and G. A label K.147(25) is at the bottom right. + +**Figure 9 – Example circuit causing common mode to differential-mode surge conversion** + +Figure 10 shows the common-mode surge voltage (black line) at the junction of R1 and R2 peaking at just over 1 500 V. When the surge voltage reaches 520 V, GDTA sparks over, lowering the conductor A voltage to about 10 V (red line). Via resistor R3 the conductor B voltage (red line) is reduced at GDTA sparkover and subsequently the conductor B voltage rises at a slower rate than before. When the conductor B voltage reaches 540 V, GDTB sparks over, lowering the conductor B voltage to about 10 V (red line). During the time between sparkovers, there is a large differential voltage of about 450 V for over 1 μs between the conductors (green line, shown inverted for clarity). + +![Graph of Voltage (V) vs Time (μs) showing surge voltages. The y-axis ranges from -500 to 1500 V, and the x-axis ranges from 0 to 50 μs. A black curve labeled 'Common-mode surge' rises from 0 V to a peak of approximately 1500 V at 15 μs and then slowly decays. A red line labeled 'Conductor A' rises to about 500 V at 7 μs, then drops to near 0 V. A red line labeled 'Conductor B' rises to about 500 V at 7 μs, then drops to near 0 V at 15 μs. A green line labeled 'Differential-mode surge' shows a negative spike to about -450 V between 7 μs and 15 μs.](e95f47f7a4c01c8889d6d46919b4c73d_img.jpg) + +Graph of Voltage (V) vs Time (μs) showing surge voltages. The y-axis ranges from -500 to 1500 V, and the x-axis ranges from 0 to 50 μs. A black curve labeled 'Common-mode surge' rises from 0 V to a peak of approximately 1500 V at 15 μs and then slowly decays. A red line labeled 'Conductor A' rises to about 500 V at 7 μs, then drops to near 0 V. A red line labeled 'Conductor B' rises to about 500 V at 7 μs, then drops to near 0 V at 15 μs. A green line labeled 'Differential-mode surge' shows a negative spike to about -450 V between 7 μs and 15 μs. + +**Figure 10 – Surge voltages** + +Changing the individual two-electrode GDTs for a single-chamber three-electrode gas discharge tube (GDT) might be expected to fix the asynchronous operation problem, but, because the first part of a three electrode GDT to spark over reduces the voltage on the other part, there is still asynchronous operation as described in [b-Gazivoda-Nikolic]. + +### 8.3.2 Capacitance + +Surge conditions can result in the charging and discharging of circuit capacitors and these currents may cause disruptions in circuit operation. The inherent capacitance of isolation barriers may need to be considered where they are in series, as shown in Figure 11. + +![Figure 11: Example of network-attached storage and power supply capacitances. The diagram shows a network-attached storage (NAS) unit connected to an Ethernet port. Inside the NAS, there is a common-mode choke and a 'Smith' termination circuit. A DC link cable connects the NAS to a power supply. The power supply has an AC input connected to AC mains and a DC output. A 200 pF capacitor is shown between the DC input of the power supply and the DC output. A 100 pF capacitor is shown between the AC input and the AC output. The diagram is labeled K.147(25).](8fbdfc3d17fb1dae7b2d8f5a287fa9fc_img.jpg) + +Figure 11: Example of network-attached storage and power supply capacitances. The diagram shows a network-attached storage (NAS) unit connected to an Ethernet port. Inside the NAS, there is a common-mode choke and a 'Smith' termination circuit. A DC link cable connects the NAS to a power supply. The power supply has an AC input connected to AC mains and a DC output. A 200 pF capacitor is shown between the DC input of the power supply and the DC output. A 100 pF capacitor is shown between the AC input and the AC output. The diagram is labeled K.147(25). + +**Figure 11 – Example of network-attached storage and power supply capacitances** + +If the port has a series common-mode choke, then there is no low impedance path for capacitive current flow. If the port has a "Smith" termination circuit, then a low impedance path for capacitive current flow exists. In this case, the transformer isolation barrier has $100/(200 + 100) = 1/3$ of the mains transient voltage across it. + +## 8.4 Magnetic coupling + +Transient magnetic fields induce voltages and, in low-impedance circuit loops, currents in the cabling. Transient magnetic fields caused by lightning can be from the lightning itself or the lightning current flowing in the lightning protection system (LPS) down-conductor on the side of a building. Inside the building, network cabling can run parallel and quite close to an external LPS down conductor. The down conductor mutual coupling inductance, $M$ , to the network cabling can be several microhenries. Figure 12 shows an example situation where a lightning current or the current in an LPS down conductor radiates a transient magnetic field that couples with open- and short-circuit twisted pair loops. The lightning current is a 100 A peak, 5/75 current impulse coupled to each loop type by a mutual inductance of 5 $\mu\text{H}$ . Figure 12 plots the lightning current (green line), a short-circuit loop conductor current (blue line) and the open-circuit loop end-to-end cable voltage (red line) against time. + +In the open-circuit loop, the induced voltage is dependent on $5 \mu\text{H} \times (dI/dt)$ , where $dI/dt$ is the lightning rate of current change with time. The time graph green line is the lightning current, the blue line is the current in any loop and the red line is the cable end-to-end voltage. The peak voltage is 110 V, indicating an initial lightning current $dI/dt$ of $110/5 = 22 \text{ A}/\mu\text{s}$ . After the lightning current peaks, the decreasing current has a negative $dI/dt$ producing a cable voltage about $-5 \text{ V}$ . Had the lightning current peak been 10 kA, the peak voltage would have been 11 kV. The peak cable voltage is balanced; for example, the NPSE end would be $-5.5 \text{ kV}$ and the NPD end would be $5.5 \text{ kV}$ . However, if the NPSE power source is connected to earth or an SPD is applied at the NPSE end, then the other cable end would experience nearly 11 kV as shown in Figure 13. + +In the short-circuit loops, the total circuit ampere-turns (ATs), try to oppose the lightning current magnetic field ATs. The time graph green line is the lightning current and the blue line is a short-circuit loop conductor current. The peak loop current is 46 A, but decays more rapidly than the lightning current. + +![Figure 12: Diagram and graph showing magnetically induced cable voltage and current from lightning current. The top part shows a lightning strike on a cable, with open-circuit loops on the left and short-circuit loops on the right. The bottom part is a graph of Voltage (V) and Current (A) vs Time (μs).](b53846f262c6904a1b45abef2e95fbd8_img.jpg) + +The top part of Figure 12 shows a lightning strike on a cable, with open-circuit loops on the left and short-circuit loops on the right. The bottom part is a graph showing the induced voltage and current over time. + +| Time (μs) | Open-circuit cable voltage (V) | Lightning current (A) | Loop short-circuit current (A) | +|-----------|--------------------------------|-----------------------|--------------------------------| +| 0 | 0 | 0 | 0 | +| 5 | 110 | 10 | 10 | +| 10 | 40 | 80 | 40 | +| 15 | 10 | 100 | 45 | +| 20 | 5 | 100 | 45 | +| 25 | 5 | 95 | 40 | +| 30 | 5 | 90 | 35 | +| 35 | 5 | 85 | 30 | +| 40 | 5 | 80 | 25 | +| 45 | 5 | 75 | 20 | +| 50 | 5 | 70 | 15 | + +Figure 12: Diagram and graph showing magnetically induced cable voltage and current from lightning current. The top part shows a lightning strike on a cable, with open-circuit loops on the left and short-circuit loops on the right. The bottom part is a graph of Voltage (V) and Current (A) vs Time (μs). + +Figure 12 – Magnetically induced cable voltage and current from lightning current + +![Figure 13: Diagram showing NPSE and NPD port voltages due to magnetic coupling. It includes a schematic of a Power sourcing equipment (PSE) and a Network powered device (NPD) connected by a cable, and two graphs showing the resulting cable voltages.](b6750d26d3dd287a4a4d49b3670a44bd_img.jpg) + +The top part of Figure 13 shows a schematic of a Power sourcing equipment (PSE) and a Network powered device (NPD) connected by a cable. The bottom part shows two graphs of cable voltage over time. + +| Condition | PSE Port Voltage (V) | NPD Port Voltage (V) | Cable Voltage (V) | +|--------------|----------------------|----------------------|-------------------| +| PSE floating | 0 | 5.5 kV | 5.5 kV | +| PSE earthed | 0 | 11 kV | 11 kV | + +Figure 13: Diagram showing NPSE and NPD port voltages due to magnetic coupling. It includes a schematic of a Power sourcing equipment (PSE) and a Network powered device (NPD) connected by a cable, and two graphs showing the resulting cable voltages. + +Figure 13 – NPSE and NPD port voltages due to magnetic coupling + +## 8.5 Electric and electromagnetic coupling + +Transient electric fields can couple into systems possibly causing interference and equipment lock-up rather than damage. Electromagnetic fields from transmitting devices can create interference and possibly equipment lock up rather than damage. + +## 8.6 Surge resistibility design approaches + +Adequate surge resistibility can be achieved by the using surge-mitigating components having linear or non-linear technology, or a combination of both component types. [b-ITU-T K.96] provides an overview of surge mitigation functions and technologies (except for screened cable technology). + +Ethernet isolation transformers [b-ITU-T K.126] usually have a withstand voltage rating that will survive the expected common-mode surge voltages. Where the surge voltage levels are unknown, or the transformer withstand voltage rating is too low, parallel-connected voltage limiters may be used to prevent transformer insulation breakdown. Common-mode chokes are also effective means of mitigating common mode surges and reducing EMC problems. + +Switching voltage limiters use gas discharge [b-ITU-T K.99] or solid-state thyristor technologies. Clamping voltage limiters use metal oxide varistor [b-ITU-T K.128] or PN junction [b-ITU-T K.103] technologies. All technologies can be used for voltage limitation of the link segment conductors to PE or between conductors. The most appropriate technology depends on the application. For example, in low-voltage signal applications, the high capacitance of the metal oxide varistor and the poor fast wave front protection level of 90 V or lower GDTs can result in operational or surge problems. + +Overcurrent limiters use either thermal or current-level technology. The response of thermal overcurrent protectors is relatively slow, limiting their use to power fault conditions or the short-circuit condition of a DC power supply, as detailed in [b-ITU-T K.144] (positive temperature coefficient thermistors) and [b-ITU-T K.140] (fuses). Electronic current limiters, which operate on current level, can be used to limit surge currents in signal circuits. + +# 9 [ITU-T K.44] and [ITU-T K.117] test circuits + +## 9.1 Test circuit overview + +Table 1 shows the test configurations presented in Figures A.1 to A.10 for [ITU-T K.44] for Ethernet ports, and Figures A.11 to A.19 for [ITU-T K.117] for SPDs and NPSE devices. Figures A.3 to A.5 and Figures A.8 to A.16 illustrate lightning tests. Figure A.7 shows power cross, Figures A.6, A.17 and A.18 insulation resistance and Figure A.19 voltage drop, as information. + +Table 2 shows the test configurations presented in Figures A.20 to A.33 for [ITU-T K.44] for ports of any type of digital subscriber line (XDSL). Table 2 also includes Figures A.1, A.2, A.9, since the circuits are as the same as in Table 1, as information. + +**Table 1 – Ethernet tests** + +| Figure | Title | Purpose | Conductors | +|--------|-------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------|------------| +| A.1 | Combination wave generator from Figure A.3-5 of [ITU-T K.44] | Impulse | N/A | +| A.2 | Power induction, power contact and rise of neutral potential generator from Figure A.3-6 of [ITU-T K.44] | AC | N/A | +| A.3 | Termination and coupling to earth of untested Ethernet ports from Figure A.6.7-1 of [ITU-T K.44] | Terminations | All | +| A.4 | Ethernet port, including PoE variants, common-mode voltage with stand test circuit from Figure A.6.7-3a of [ITU-T K.44] | Common-mode-current hogging | All | +| A.5 | Ethernet port, including PoE variants, common mode to differential mode conversion surge test circuit from Figure A.6.7-4 of [ITU-T K.44] | Common-mode to differential-mode conversion | All | + +**Table 1 – Ethernet tests** + +| Figure | Title | Purpose | Conductors | +|---------------|------------------------------------------------------------------------------------------------------------------|---------------------------------------------|-------------------| +| A.6 | Ethernet port, including PoE variants, DC insulation resistance test circuit from Figure A.6.7-3 of [ITU-T K.44] | Insulation | All | +| A.7 | Ethernet port, including PoE variants, power cross test circuit from Figure A.6.7-7 of [ITU-T K.44] | Power cross | All | +| A.8 | PoE port powering pair transverse/differential surge test circuit from Figure A.6.7-2 of [ITU-T K.44] | Powering differential | Power | +| A.9 | Ethernet port differential-mode surge test circuit including PoE variants from Figure A.6.7-5 of [ITU-T K.44] | Data port differential | Data | +| A.10 | Ethernet screened cable port screen connection high current bonding test from Figure A.6.7-6 of [ITU-T K.44] | High current | Screen | +| A.11 | Impulse limiting voltage under common-mode surge conditions | Common-mode-current hogging | All | +| A.12 | Single twisted pair differential-mode surge test circuit | Differential | Pairs | +| A.13 | Power feed differential-mode surge test circuit | Powering differential-mode | Powering pairs | +| A.14 | Twisted pair common mode to differential-mode voltage surge conversion test circuit | Common-mode to differential-mode conversion | All | +| A.15 | Power feed pair common mode to differential mode surge conversion test circuit | Common-mode to differential-mode conversion | Powering pairs | +| A.16 | Screen bonding test | High current | Screen | +| A.17 | Test circuit to measure the insulation resistance of an SPD with a PE terminal or screen terminals, or both | Insulation | Pairs | +| A.18 | Test circuit to measure the insulation resistance of an isolating transformer SPD without a PE terminal | Insulation | Pairs | +| A.19 | Test circuit to measure the PoE SPD DC input/output voltage drop | Item powering loss | All | + +**Table 2 – Tests for ports of XDSL** + +| Figure | Title | Purpose | Conductors | +|--------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------|----------------|-------------------| +| A.20 | 10/700 µs voltage surge generator from Figure A.3-1 of [ITU-T K.44] | Impulse | N/A | +| A.21 | Output of 8/20 current generator from Figure A.3-4 of [ITU-T K.44] | Impulse | N/A | +| A.2
(duplication
from Table 1) | Power induction, power contact and rise of neutral potential generator from Figure A.3-6 of [ITU-T K.44] | AC | N/A | +| A.22 | Decoupling network for auxiliary equipment (AE) connected to the tested external symmetric pair port from Figure A.5-3 of [ITU-T K.44] | Terminations | All | + +**Table 2 – Tests for ports of XDSL** + +| Figure | Title | Purpose | Conductors | +|-----------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------|------------------------| +| A.23 | Termination and coupling to earth of untested external symmetric pair ports from Figure A.5-10 of [ITU-T K.44] | Terminations | All | +| A.24 | Connection of protection for the untested external symmetric pair port coupled to earth from Figure A.5-17 of [ITU-T K.44] | Terminations | All | +| A.25 (a, b) | Example of a test circuit for a transverse/differential overvoltage or overcurrent on a single external symmetric pair port from Figure A.6.1-1 (a, b) of [ITU-T K.44] | Differential | Pairs | +| A.26 | Example of a test circuit for an overvoltage or overcurrent on a single external symmetric pair port to earth from Figure A.6.1-2 of [ITU-T K.44] | Common-mode | All | +| A.27 | Example of a test circuit for an overvoltage or overcurrent on an external multiple symmetric pairs port, external multiple symmetric pair ports or a combination of both, to earth from Figure A.6.1-4 of [ITU-T K.44] | Common-mode | All | +| A.28 | Example of a test circuit for an overvoltage or overcurrent on a single external symmetric pair port to another external port from Figure A.6.1-3 of [ITU-T K.44] | External port to another external port | All | +| A.29 | Example of test circuit for an overvoltage or overcurrent on an external multiple symmetric pairs port, external multiple symmetric pair ports or a combination of both, to another external port from Figure A.6.1-5 of [ITU-T K.44] | External port to another external port | All | +| A.1
(duplication from Table 1) | Combination wave generator from Figure A.3-5 of [ITU-T K.44] | Impulse | N/A | +| A.30 | Decoupling network for AE connected to the tested internal unshielded cable port from Figure A.6.5-7 of [ITU-T K.44] | Terminations | All | +| A.31 | Termination of untested internal symmetric pair ports from Figure A.5-14a of [ITU-T K.44] | Terminations | All | +| A.32 | Coupling to earth and termination of untested internal symmetric pair ports from Figure A.5-14b of [ITU-T K.44] | Terminations | All | +| A.33 | Example of test circuit for an overvoltage or overcurrent on an internal port connected to an unshielded cable with single or multiple symmetric pairs to earth from Figure A.6.5-1 of [ITU-T K.44] | Common-mode | All | +| A.34 | Example of a test circuit for an overvoltage or overcurrent on an internal port connected to a shielded cable to earth from Figure A.6.5-2 of [ITU-T K.44] | Common-mode | All (including screen) | + +**Table 2 – Tests for ports of XDSL** + +| Figure | Title | Purpose | Conductors | +|--------------------------------------|------------------------------------------------------------------------------------------------------------------|--------------|------------| +| A.9
(duplication
from Table 1) | Twisted pair transverse/differential surge test circuit for ports having one from Figure A.6.7-5 of [ITU-T K.44] | Differential | Pairs | + +## 9.2 Power fault resistibility + +The power cross test shown in Figure A.7 is for direct contact with the local AC mains. As the highest domestic AC mains peak voltage is below 400 V, ports passing the 500 V DC insulation test do not require power cross testing. + +## 9.3 RP link + +PD levels and supported loop resistances for SPE RP circuits can be found in clause 104, at 104.2 and 104.3 of [b-IEEE 802.3] for loop resistance and power requirement, respectively. Since loop resistance is related to both wire gauge and length, appropriate loop lengths can be determined from the combination of these parameters according to these clauses. + +It should be noted that SPE RP circuits according to [b-IEEE 802.3] are capable of delivering a constant power level (called a class, which has variations of class 0 to class 15) up to the specified loop resistance shown in clause 104.3 for that class, as shown in clause 104.2. The maximum power delivered for a powering class corresponds to the loop resistance specified. + +# Annex A + +## Ethernet surge test circuits based on ITU-T K-series Recommendations + +(This annex forms an integral part of this Recommendation.) + +### A.1 Introduction + +The circuits in this annex are derived from the following ITU-T K-series Recommendations: + +- [ITU-T K.20] +- [ITU-T K.21] +- [ITU-T K.44] +- [ITU-T K.45] +- [ITU-T K.117]. + +Test levels are location-dependent and specific values are given in: [ITU-T K.20] (telecommunication centre); [ITU-T K.21] (customer premises); and [ITU-T K.45] (access and trunk networks). Ethernet ports are classified as either internal ports, whose connection cables are entirely within the building, or external ports, whose connection cables leave the building. Testing covers lightning surges, AC mains power cross, DC insulation resistance and screened cable connection bonding. For actual testing, it is necessary to consult each of the referenced documents. + +## A.2 Ethernet port testing + +#### A.2.1 Test generators + +##### A.2.1.1 1.2/50-8/20 generator + +Figure A.1 shows a combination wave generator. + +![Circuit diagram of a 1.2/50-8/20 Combination wave generator. The circuit consists of a voltage source U_C in series with a switch S_1. This is followed by a parallel combination of a capacitor C_1 = 5.93 μF and a resistor R_1 = 20.2 Ω. The output of this parallel section is connected to a series combination of an inductor L_1 = 10.9 μH and a resistor R_2 = 0.841 Ω. The output of this series section is connected to a parallel combination of a resistor R_3 = 26.1 Ω and the 'Feed' terminal. The 'Return' terminal is connected to the common return line of the circuit. The text '1.2/50-8/20 Combination wave generator (Simplified circuit for SPICE modelling)' is written below the circuit diagram. The identifier 'K.147(23)_FA.1' is in the bottom right corner of the diagram box.](86d30a7d5a9cd4ee5456b5962ae3420a_img.jpg) + +1.2/50-8/20 Combination wave generator +(Simplified circuit for SPICE modelling) + +K.147(23)\_FA.1 + +Circuit diagram of a 1.2/50-8/20 Combination wave generator. The circuit consists of a voltage source U\_C in series with a switch S\_1. This is followed by a parallel combination of a capacitor C\_1 = 5.93 μF and a resistor R\_1 = 20.2 Ω. The output of this parallel section is connected to a series combination of an inductor L\_1 = 10.9 μH and a resistor R\_2 = 0.841 Ω. The output of this series section is connected to a parallel combination of a resistor R\_3 = 26.1 Ω and the 'Feed' terminal. The 'Return' terminal is connected to the common return line of the circuit. The text '1.2/50-8/20 Combination wave generator (Simplified circuit for SPICE modelling)' is written below the circuit diagram. The identifier 'K.147(23)\_FA.1' is in the bottom right corner of the diagram box. + +SPICE: simulation program with integrated circuit emphasis + +**Figure A.1 – Combination wave generator based on Figure A.3-5 of [ITU-T K.44]** + +##### A.2.1.2 AC generator + +Figure A.2 shows an AC generator. + +![Figure A.2: Power induction, power contact and rise of neutral potential generator circuit diagram. It shows an AC voltage source U(AC) connected to a switch (SW). The switch has two positions: one connected to a current limit resistor (R) leading to ground g1, and another connected to a current limit resistor (R) leading to ground g2. A timing circuit is connected between the switch and the return path. The return path is labeled 'Return' and 'K.147(23)_FA.2'.](c5452f95f3b28f1bfe29e84fbc2e1267_img.jpg) + +Figure A.2: Power induction, power contact and rise of neutral potential generator circuit diagram. It shows an AC voltage source U(AC) connected to a switch (SW). The switch has two positions: one connected to a current limit resistor (R) leading to ground g1, and another connected to a current limit resistor (R) leading to ground g2. A timing circuit is connected between the switch and the return path. The return path is labeled 'Return' and 'K.147(23)\_FA.2'. + +**Figure A.2 – Power induction, power contact and rise of neutral potential generator based on Figure A.3-6 of [ITU-T K.44]** + +For the resistance value, see the test table in the appropriate product Recommendation. + +#### A.2.2 Untested port termination and coupling network + +Figure A.3 shows the termination and coupling to earth of untested Ethernet ports. + +![Figure A.3: Termination and coupling to earth of untested Ethernet ports. Part (a) shows the 'Coupling/decoupling circuit' from the 'Auxiliary equipment' (EUT) to the 'EUT reference bar'. It consists of eight 10 Ω resistors connected between the EUT reference bar and the auxiliary equipment. Part (b) shows the 'Termination circuit' for an untested Ethernet port, which consists of four 10 Ω resistors connected between the EUT reference bar and the auxiliary equipment.](7e1c9b51e067a48cd0fcc9748d8bd8d8_img.jpg) + +Figure A.3: Termination and coupling to earth of untested Ethernet ports. Part (a) shows the 'Coupling/decoupling circuit' from the 'Auxiliary equipment' (EUT) to the 'EUT reference bar'. It consists of eight 10 Ω resistors connected between the EUT reference bar and the auxiliary equipment. Part (b) shows the 'Termination circuit' for an untested Ethernet port, which consists of four 10 Ω resistors connected between the EUT reference bar and the auxiliary equipment. + +**Figure A.3 – Termination and coupling to earth of untested Ethernet ports based on Figure A.6.7-1 of [ITU-T K.44]: a – Ethernet coupling circuit from the equipment under test (EUT); b – termination circuit for an untested Ethernet port** + +#### A.2.3 Common-mode test circuits + +In Figure A.4, the single resistor feed maximizes the current into protected terminals that current hog. If there is no protective function, then the insulation withstand voltage is verified. + +![Figure A.4: Common-mode test circuit diagram for an Ethernet port. The diagram shows an Equipment Under Test (EUT) with an Ethernet port (terminals 1, 2, 3, 4, 5, 6, 7, 8, and a Screen). A coupling network with a resistor R is connected to the Ethernet port. A 1.2/50-8/20 Combination wave generator (Figure B.1) is connected to the coupling network. The EUT is connected to a power source via a power port. The EUT reference bar is connected to the generator return. The key indicates: a) RJ45 screen cable connection, b) EUT protective or functional earth connection, c, d) terminals of all other signal ports, e) Power port terminals. The diagram also shows an ammeter (A) for leakage current, a DC test voltage (U_DC) limited to 100 mA, and a switch (SW) closed for current measurement. The insulation resistance is calculated as U_DC/I_L.](552265bdbcf6d43d341fd018a9076269_img.jpg) + +Figure A.4: Common-mode test circuit diagram for an Ethernet port. The diagram shows an Equipment Under Test (EUT) with an Ethernet port (terminals 1, 2, 3, 4, 5, 6, 7, 8, and a Screen). A coupling network with a resistor R is connected to the Ethernet port. A 1.2/50-8/20 Combination wave generator (Figure B.1) is connected to the coupling network. The EUT is connected to a power source via a power port. The EUT reference bar is connected to the generator return. The key indicates: a) RJ45 screen cable connection, b) EUT protective or functional earth connection, c, d) terminals of all other signal ports, e) Power port terminals. The diagram also shows an ammeter (A) for leakage current, a DC test voltage (U\_DC) limited to 100 mA, and a switch (SW) closed for current measurement. The insulation resistance is calculated as U\_DC/I\_L. + +##### Key + +- | | | | | +|------|-----------------------------------------------|----------|---------------------------------------| +| a | RJ45 screen cable connection | A | Ammeter for leakage current, $I_L$ | +| b | EUT protective or functional earth connection | $U_{DC}$ | DC test voltage (limited to 100 mA) | +| c, d | terminals of all other signal ports | SW | Switch closed for current measurement | +| e | Power port terminals | | | +- Insulation resistance = $U_{DC}/I_L$ + +**Figure A.4 – Ethernet port, including PoE variants, common-mode voltage withstands test circuit based on Figure A.6.7-3a of [ITU-T K.44]** + +In Figure A.5, feeding each terminal with its own resistor checks if any voltage-limiting function causes a damaging common-mode to differential-mode conversion. + +![Circuit diagram for common mode to differential mode conversion surge test on an Ethernet port. The diagram shows an EUT (Equipment Under Test) with an Ethernet port (terminals 1, 2, 3, 6, 4, 5, 7, 8) connected to a coupling network. The coupling network consists of eight resistors (R) connected to the Ethernet port terminals and a common line. This common line is connected to a 1.2/50-8/20 Combination wave generator (Figure B.1) and a generator return. The generator return is connected to an EUT reference bar at point 'a'. The EUT reference bar is also connected to the EUT protective or functional earth connection (point 'b'). The EUT has a power port connected to a power source through a switch (SW) and an ammeter (A). The power port terminals are labeled 'e'. The EUT also has other ports (c, d) connected to a termination and decoupling network. The diagram is labeled K.147(23)_FA.5.](cbdfdade780e677eb1c1aef3081ce9ef_img.jpg) + +Circuit diagram for common mode to differential mode conversion surge test on an Ethernet port. The diagram shows an EUT (Equipment Under Test) with an Ethernet port (terminals 1, 2, 3, 6, 4, 5, 7, 8) connected to a coupling network. The coupling network consists of eight resistors (R) connected to the Ethernet port terminals and a common line. This common line is connected to a 1.2/50-8/20 Combination wave generator (Figure B.1) and a generator return. The generator return is connected to an EUT reference bar at point 'a'. The EUT reference bar is also connected to the EUT protective or functional earth connection (point 'b'). The EUT has a power port connected to a power source through a switch (SW) and an ammeter (A). The power port terminals are labeled 'e'. The EUT also has other ports (c, d) connected to a termination and decoupling network. The diagram is labeled K.147(23)\_FA.5. + +K.147(23)\_FA.5 + +##### **Key** + +- | | | | | +|------|-----------------------------------------------|----------|---------------------------------------| +| a | RJ45 screen cable connection | A | Ammeter for leakage current, $I_L$ | +| b | EUT protective or functional earth connection | $U_{DC}$ | DC test voltage (limited to 100 mA) | +| c, d | terminals of all other signal ports | SW | Switch closed for current measurement | +| e | Power port terminals | | | + +Insulation resistance = $U_{DC}/I_L$ + +**Figure A.5 – Ethernet port, including PoE variants, common mode to differential mode conversion surge test circuit based on Figure A.6.7-4 of [ITU-T K.44]** + +Figure A.6 represents the 500 V DC test used to measure the insulation leakage current, which is required to be below 250 $\mu\text{A}$ . + +![Circuit diagram for DC insulation resistance test on an Ethernet port. The diagram shows an Equipment Under Test (EUT) with a 'Transformer isolated port' (terminals 1-8 and a screen) and 'Other ports'. A DC test voltage source U_DC is connected in series with a switch (SW) and an ammeter (A) to the screen terminal (a). The EUT's protective earth connection (b) is connected to the EUT reference bar. Terminals of other signal ports (c, d) and power port terminals (e) are also connected to the reference bar. The current measured by the ammeter is I_L. The diagram is labeled K.147(23)_FA.6.](aaf3e6e44cdeabd6d1df869c5f392ea1_img.jpg) + +Circuit diagram for DC insulation resistance test on an Ethernet port. The diagram shows an Equipment Under Test (EUT) with a 'Transformer isolated port' (terminals 1-8 and a screen) and 'Other ports'. A DC test voltage source U\_DC is connected in series with a switch (SW) and an ammeter (A) to the screen terminal (a). The EUT's protective earth connection (b) is connected to the EUT reference bar. Terminals of other signal ports (c, d) and power port terminals (e) are also connected to the reference bar. The current measured by the ammeter is I\_L. The diagram is labeled K.147(23)\_FA.6. + +##### **Key** + +- | | | | | +|------|-----------------------------------------------|----------|---------------------------------------| +| a | RJ45 screen cable connection | A | Ammeter for leakage current, $I_L$ | +| b | EUT protective or functional earth connection | $U_{DC}$ | DC test voltage (limited to 100 mA) | +| c, d | terminals of all other signal ports | SW | Switch closed for current measurement | +| e | Power port terminals | | | + +Insulation resistance = $U_{DC}/I_L$ + +**Figure A.6 – Ethernet port, including PoE variants, DC insulation resistance test circuit based on Figure A.6.7-3 of [ITU-T K.44]** + +The test shown in Figure A.7 is only applied to an Ethernet port that fails the 500 V DC insulation resistance test in any polarity. Ports passing the 500 V DC insulation resistance test do not conduct appreciable current when mains voltages of up to 350 V AC are applied. + +![Figure A.7: Ethernet port, including PoE variants, power cross test circuit based on Figure A.6.7-7 of [ITU-T K.44].](8c348bf9c2c81b018017ae1d19506a9a_img.jpg) + +The diagram illustrates a power cross test circuit for an Ethernet port. On the left, an 'AC source Figure B.2' is connected to an 'EUT reference bar' at points 'a' and 'Generator return'. The 'EUT reference bar' has four connection points labeled 'a', 'b', 'c', and 'd'. Point 'a' is connected to the 'Screen' of an 'Ethernet port' (pins 1, 2, 3, 4, 5, 6, 7, 8). Point 'b' is connected to the 'E' (Earth) terminal of the 'Ethernet port'. Point 'c' is connected to 'Other ports' via a 'Termination and decoupling' block. Point 'd' is connected to the 'PE' (Protective Earth) terminal of a 'Power port'. The 'Power port' is connected to an AC source symbol. The 'EUT' (Equipment Under Test) is shown as a large rectangle containing the 'Ethernet port', 'Power port', and 'Other ports'. + +Figure A.7: Ethernet port, including PoE variants, power cross test circuit based on Figure A.6.7-7 of [ITU-T K.44]. + +###### **Key** + +- | | | | | +|------|-----------------------------------------------|----------|---------------------------------------| +| a | RJ45 screen cable connection | A | Ammeter for leakage current, $I_L$ | +| b | EUT protective or functional earth connection | $U_{DC}$ | DC test voltage (limited to 100 mA) | +| c, d | terminals of all other signal ports | SW | Switch closed for current measurement | +| e | Power port terminals | | | +- Insulation resistance = $U_{DC}/I_L$ + +**Figure A.7 – Ethernet port, including PoE variants, power cross test circuit based on Figure A.6.7-7 of [ITU-T K.44]** + +#### **A.2.4 Differential-mode test circuits** + +In Figure A.8, for NPSE, power injection equipment and NPD ports, test in switch (SW) positions A and B. If the NPSE specifies the powering pairs, then the testing is only done on those pairs. This configuration verifies NPSE or NPD powering resistibility. + +![Circuit diagram for PoE port powering pair transverse/differential surge test. A 1.2/50-8/20 combination wave generator is connected to a circuit with a series resistor R and a shunt resistor R1. A switch SW selects between position A (connecting to RJ45 pins 1, 2, 3, 6) and position B (connecting to RJ45 pins 4, 5, 7, 8) of a transformer-isolated port within the EUT. The EUT also features a power port and other ports connected to termination and decoupling. An EUT reference bar connects points a (RJ45 screen), b (earth), and c/d (other signal ports).](69b7bd65e85cdef6fdd7fb0a8194257c_img.jpg) + +Circuit diagram for PoE port powering pair transverse/differential surge test. A 1.2/50-8/20 combination wave generator is connected to a circuit with a series resistor R and a shunt resistor R1. A switch SW selects between position A (connecting to RJ45 pins 1, 2, 3, 6) and position B (connecting to RJ45 pins 4, 5, 7, 8) of a transformer-isolated port within the EUT. The EUT also features a power port and other ports connected to termination and decoupling. An EUT reference bar connects points a (RJ45 screen), b (earth), and c/d (other signal ports). + +K.147(23)\_FA.8 + +##### **Key** + +| | | | | +|-----------------|-----------------------------------------------|----------------|-----------------------------------------------------| +| a | RJ45 screen cable connection | R | Series current limiting resistor of resistance 10 Ω | +| b | EUT protective or functional earth connection | R 1 | Shunt resistor of resistance 10 Ω | +| c, d | terminals of all other signal ports | SW | Switch | +| 1,2,3,4,5,6,7,8 | Ethernet RJ45 pin numbers | | | + +**Figure A.8 – PoE port powering pair transverse/differential surge test circuit based on Figure A.6.7-2 of [ITU-T K.44]** + +In Figure A.8: + +SW in position A: Test PoE Mode A powering terminals 1/2-3/6; + +SW in position B: Test PoE Mode B powering terminals 4/5-7/8. + +Figure A.9 tests the resistibility of Ethernet port data terminals under high $dI/dt$ conditions. Resistor $R_1$ and capacitor $C_1$ shorten the surge time to prevent the application of excessive port energy. This test is conducted on each terminal pair selected by setting that pair's switch to the up position, and the remaining switches set to the down position. Surging is performed with alternating polarities. + +![Circuit diagram of an Ethernet port differential-mode surge test circuit. On the left, a '1.2/50-8/20 Combination wave generator' is connected to a 'Coupling network to shorten the impulse duration' containing resistors R1, R2 and capacitor C1. The generator's return path is connected to the 'EUT reference bar' at point 'a'. The coupling network's output is connected to a series of switches SW1, SW2, ..., SWn. Each switch can connect a pair of terminals (1a, 1b; 2a, 2b; ..., na, nb) to either the coupling network (up position) or to functional earth (down position). The 'EUT' (Equipment Under Test) has these terminals, a 'Screen' connection, and 'Other ports'. The 'Other ports' are connected to a 'Termination and decoupling' network, which is then connected to the 'EUT reference bar' at points 'c', 'd', and 'e'. A 'Power port' is connected to a 'Power source' and its earth terminal 'E' is connected to the 'EUT reference bar' at point 'b'. The 'EUT reference bar' is a common connection point for the generator return, earth, and other port terminations.](11edb7fcedf09ac6a817f8d7b8c61eec_img.jpg) + +Circuit diagram of an Ethernet port differential-mode surge test circuit. On the left, a '1.2/50-8/20 Combination wave generator' is connected to a 'Coupling network to shorten the impulse duration' containing resistors R1, R2 and capacitor C1. The generator's return path is connected to the 'EUT reference bar' at point 'a'. The coupling network's output is connected to a series of switches SW1, SW2, ..., SWn. Each switch can connect a pair of terminals (1a, 1b; 2a, 2b; ..., na, nb) to either the coupling network (up position) or to functional earth (down position). The 'EUT' (Equipment Under Test) has these terminals, a 'Screen' connection, and 'Other ports'. The 'Other ports' are connected to a 'Termination and decoupling' network, which is then connected to the 'EUT reference bar' at points 'c', 'd', and 'e'. A 'Power port' is connected to a 'Power source' and its earth terminal 'E' is connected to the 'EUT reference bar' at point 'b'. The 'EUT reference bar' is a common connection point for the generator return, earth, and other port terminations. + +K.147(23)\_FA.9 + +##### Key + +| | | | | +|------|----------------------------------------------------------------------------------------|-------|--------------------------------------| +| a | RJ45 screen (shielded) cable connection for screened twisted pair Ethernet connections | $R_1$ | $10\ \Omega$ | +| b | EUT protective or functional earth connection | $R_2$ | $10\ \Omega$ | +| c, d | terminals of all other signal ports | $C_1$ | $0.50 \pm 0.05\ \mu\text{F}$ at 5 kV | +| e | Power port terminals | SW | Switch | + +**Figure A.9 – Ethernet port differential-mode surge test circuit including PoE variants based on Figure A.6.7-5 of [ITU-T K.44]** + +In Figure A.9, twisted-pair terminal pairs are 1a + 1b, 2a + 2b to *n*a + *n*b, served by the corresponding switches $SW_1$ , $SW_2$ to $SW_n$ . + +For each terminal pair, when the switch is in the up position, one terminal is connected to the coupling network. When the switch is in the down position, that terminal is connected to functional earth. + +Capacitor $C_1$ has: equivalent series resistance: $< 0.5\ \Omega$ ; inductance: $< 1\ \mu\text{H}$ . Different parasitic values are acceptable provided $dI/dt$ requirements are met. + +The initial rate of rise of the short-circuit current, $dI/dt$ , at 2.5 kV generator charging voltage shall be $60 \pm 10\ \text{A}/\mu\text{s}$ in the first $0.5\ \mu\text{s}$ . + +See Figure A.10. + +![Diagram of an Ethernet screened cable port screen connection high current bonding test setup. On the left, a '1.2/50-8/20 Combination wave generator' is shown. Its positive terminal is connected to a resistor 'R', which is then connected to the 'Screen pin or screen' of the 'EUT' (Equipment Under Test). The negative terminal of the generator is connected to the 'Generator return' line. The 'EUT' has multiple pins labeled 1a, 1b, 2a, 2b, ..., na, nb, and 'Screen pin or screen'. The 'Generator return' line connects to the 'EUT reference bar' at point 'a'. The 'Screen pin or screen' of the 'EUT' is connected to the 'EUT reference bar' at point 'b'. The 'EUT reference bar' is also connected to the 'E' (Earth) terminal. The diagram is labeled 'K.147(23)_FA.10'.](c494cd874a082a97b50b3c4d3938f467_img.jpg) + +Diagram of an Ethernet screened cable port screen connection high current bonding test setup. On the left, a '1.2/50-8/20 Combination wave generator' is shown. Its positive terminal is connected to a resistor 'R', which is then connected to the 'Screen pin or screen' of the 'EUT' (Equipment Under Test). The negative terminal of the generator is connected to the 'Generator return' line. The 'EUT' has multiple pins labeled 1a, 1b, 2a, 2b, ..., na, nb, and 'Screen pin or screen'. The 'Generator return' line connects to the 'EUT reference bar' at point 'a'. The 'Screen pin or screen' of the 'EUT' is connected to the 'EUT reference bar' at point 'b'. The 'EUT reference bar' is also connected to the 'E' (Earth) terminal. The diagram is labeled 'K.147(23)\_FA.10'. + +**Figure A.10 – Ethernet screened cable port screen connection high current bonding test based on Figure A.6.7-6 of [ITU-T K.44]** + +This high-current surge test verifies that the equipment current capability to earth is adequate. + +#### **A.2.5 Ethernet intermediate link connections** + +Intermediate link connections are items like connectors, SPDs, injector PSEs and daisy-chained NPDs. Each of these items has two ports. For example, Ethernet SPDs typically have two ports: one for link cable connection and the other for equipment connection. Special testing is required for these two-port devices, as there is a need for additional loads to be attached to the port that are not being directly tested. Such testing is covered by [ITU-T K.117]. Figure A.11 is functionally similar to Figure A4. + +![Circuit diagram for impulse limiting voltage under common-mode surge conditions. It shows a 1.2/50-8/20 combination wave generator connected via a 5 ohm resistor (Rg) to the cable ports of an SPD. The equipment ports are connected to a termination circuit containing resistors R1-R8, capacitors C1-C4, and resistors R11-R14. A reference bar is connected to the generator return/earth and the SPD's PE terminal. Component values: R1 to R8: 1 ohm, C1 to C4: 10 nF, 300 V, R11 to R14: 75 ohm. The termination circuit also includes a 1 nF, 3 kV capacitor C5.](692541e65db4dc852988ce77ebb60ce5_img.jpg) + +1.2/50-8/20 Combination wave generator + +$R_9: 5 \Omega$ + +Cable port: 1, 2, 3, 6, 4, 5, 7, 8 + +Equipment port: 1, 2, 3, 6, 4, 5, 7, 8 + +SPD + +PE + +Screen + +Reference bar + +Generator return/Earth + +a b c d + +$R_1$ to $R_8: 1 \Omega$ + $C_1$ to $C_4: 10 \text{ nF}, 300 \text{ V}$ + $R_{11}$ to $R_{14}: 75 \Omega$ + +Termination circuit + +$1 \text{ nF}$ $C_5$ + $3 \text{ kV}$ + +K.147(23)\_FA.11 + +Circuit diagram for impulse limiting voltage under common-mode surge conditions. It shows a 1.2/50-8/20 combination wave generator connected via a 5 ohm resistor (Rg) to the cable ports of an SPD. The equipment ports are connected to a termination circuit containing resistors R1-R8, capacitors C1-C4, and resistors R11-R14. A reference bar is connected to the generator return/earth and the SPD's PE terminal. Component values: R1 to R8: 1 ohm, C1 to C4: 10 nF, 300 V, R11 to R14: 75 ohm. The termination circuit also includes a 1 nF, 3 kV capacitor C5. + +**Figure A.11 – Impulse limiting voltage under common-mode surge conditions** + +Figure A.12 is functionally similar to Figure A.8, but for a single twisted pair. + +![Circuit diagram for single twisted pair differential-mode surge test circuit. It shows a 1.2/50-8/20 generator connected via a 10 ohm resistor (Rg) and a 10 ohm resistor (R10) to the cable ports of an SPD through switches (SW). The equipment ports are connected to a termination circuit with resistors R1-R8, capacitors C1-C4, and resistors R11-R14. Differential voltage is measured across the equipment ports. Component values: R1 to R8: 1 ohm, C1 to C4: 10 nF, 300 V, R11 to R14: 75 ohm. The termination circuit also includes a 1 nF, 3 kV capacitor C5.](e05b36c0d46549e681ce6581422c66b2_img.jpg) + +1.2/50-8/20 generator + +$R_9: 10 \Omega$ + +$R_{10}: 10 \Omega$ + +SW (1-2), SW (3-6), SW (4-5), SW (7-8) + +Cable port: 1, 2, 3, 6, 4, 5, 7, 8 + +Equipment port: 1, 2, 3, 6, 4, 5, 7, 8 + +SPD + +Differential voltage + +PE + +Screen + +Reference bar + +Generator return/Earth + +a b c d + +$R_1$ to $R_8: 1 \Omega$ + $C_1$ to $C_4: 10 \text{ nF}, 300 \text{ V}$ + $R_{11}$ to $R_{14}: 75 \Omega$ + +Termination circuit + +$1 \text{ nF}$ $C_5$ + $3 \text{ kV}$ + +K.147(23)\_FA.12 + +Circuit diagram for single twisted pair differential-mode surge test circuit. It shows a 1.2/50-8/20 generator connected via a 10 ohm resistor (Rg) and a 10 ohm resistor (R10) to the cable ports of an SPD through switches (SW). The equipment ports are connected to a termination circuit with resistors R1-R8, capacitors C1-C4, and resistors R11-R14. Differential voltage is measured across the equipment ports. Component values: R1 to R8: 1 ohm, C1 to C4: 10 nF, 300 V, R11 to R14: 75 ohm. The termination circuit also includes a 1 nF, 3 kV capacitor C5. + +**Figure A.12 – Single twisted pair differential-mode surge test circuit** + +Figure A.13 shows a power feed differential-mode surge test circuit. + +![Figure A.13 – Power feed differential-mode surge test circuit. This schematic diagram shows a 1.2/50-8/20 Generator connected to a double pole, two position selector switch (SW). The switch has two positions, A and B. In position A, the generator is connected through a resistor R9 (10 Ω) to the Cable port (pins 1, 2, 3, 6) of an SPD. In position B, it is connected through a resistor R10 (10 Ω) to the Equipment port (pins 4, 5, 7, 8) of the same SPD. The SPD is connected to a Reference bar (pins a, b, c) via its Screen and PE terminals. The Equipment port is connected to a PoE port termination circuit. This circuit contains two sets of diodes: D1 to D4 and D6 to D9 are B1100/B Schottky rectifier diodes or equivalent 1 A, 100 V diodes; D5 and D10 are SMAJ58A or equivalent 400 W avalanche breakdown diodes. Capacitors C1 and C2 are 100 nF at 100 V. The diagram is labeled K.147(23)_FA.13.](08dce7ad4c512fdf0c0cde60415fade6_img.jpg) + +Figure A.13 – Power feed differential-mode surge test circuit. This schematic diagram shows a 1.2/50-8/20 Generator connected to a double pole, two position selector switch (SW). The switch has two positions, A and B. In position A, the generator is connected through a resistor R9 (10 Ω) to the Cable port (pins 1, 2, 3, 6) of an SPD. In position B, it is connected through a resistor R10 (10 Ω) to the Equipment port (pins 4, 5, 7, 8) of the same SPD. The SPD is connected to a Reference bar (pins a, b, c) via its Screen and PE terminals. The Equipment port is connected to a PoE port termination circuit. This circuit contains two sets of diodes: D1 to D4 and D6 to D9 are B1100/B Schottky rectifier diodes or equivalent 1 A, 100 V diodes; D5 and D10 are SMAJ58A or equivalent 400 W avalanche breakdown diodes. Capacitors C1 and C2 are 100 nF at 100 V. The diagram is labeled K.147(23)\_FA.13. + +##### **Key** + +- D1 to D4, D6 to D9 B1100/B Schottky rectifier diodes or equivalent 1 A, 100 V diodes    C1, C2 100 nF at 100 V + D5, D10 SMAJ58A or equivalent 400 W avalanche breakdown diodes    R9, R10 10 Ω + SW Double pole, two position selector switch + +**Figure A.13 – Power feed differential-mode surge test circuit** + +Figure A.14 shows a twisted pair common mode to differential-mode voltage surge conversion test circuit. + +![Figure A.14 – Twisted pair common mode to differential-mode voltage surge conversion test circuit. This schematic diagram shows a 1.2/50-8/20 generator connected to a Generator current sharing network. The network consists of eight resistors, R1 through R8, each 40 Ω, connected in series between the generator and the Cable port (pins 1, 2, 3, 6) of an SPD. The Equipment port (pins 4, 5, 7, 8) of the SPD is connected to a Termination circuit. This circuit contains four resistors: R12 (150 Ω), R36 (150 Ω), R45 (150 Ω), and R78 (150 Ω). Each resistor is connected across a twisted pair, with the differential voltage indicated by double-headed arrows. The SPD is connected to a Reference bar (pins a, b, c) via its Screen and PE terminals. The diagram is labeled K.147(23)_FA.14.](5478f70a6cef3e5672b2b22d28830cfb_img.jpg) + +Figure A.14 – Twisted pair common mode to differential-mode voltage surge conversion test circuit. This schematic diagram shows a 1.2/50-8/20 generator connected to a Generator current sharing network. The network consists of eight resistors, R1 through R8, each 40 Ω, connected in series between the generator and the Cable port (pins 1, 2, 3, 6) of an SPD. The Equipment port (pins 4, 5, 7, 8) of the SPD is connected to a Termination circuit. This circuit contains four resistors: R12 (150 Ω), R36 (150 Ω), R45 (150 Ω), and R78 (150 Ω). Each resistor is connected across a twisted pair, with the differential voltage indicated by double-headed arrows. The SPD is connected to a Reference bar (pins a, b, c) via its Screen and PE terminals. The diagram is labeled K.147(23)\_FA.14. + +**Figure A.14 – Twisted pair common mode to differential-mode voltage surge conversion test circuit** + +Figure A.15 shows a power feed pair common mode to differential mode surge conversion test circuit. + +![Circuit diagram for Figure A.15 showing a power feed pair common mode to differential mode surge conversion test circuit. It includes a 1.2/50-8/20 Generator, a Generator current sharing network with resistors R1-R8 (40 Ω), an SPD, a Termination circuit with resistors R11-R18 (1 Ω), and a Reference bar. The diagram shows connections between cable ports (1-8) and equipment ports (10, 20, 30, 60, 40, 50, 70, 80). It also indicates PoE differential voltage, Mode A differential voltage, and Mode B differential voltage. The reference bar is connected to the generator return/earth and has points a, b, and c.](399a5af4f606059626c92c92279d54b7_img.jpg) + +Circuit diagram for Figure A.15 showing a power feed pair common mode to differential mode surge conversion test circuit. It includes a 1.2/50-8/20 Generator, a Generator current sharing network with resistors R1-R8 (40 Ω), an SPD, a Termination circuit with resistors R11-R18 (1 Ω), and a Reference bar. The diagram shows connections between cable ports (1-8) and equipment ports (10, 20, 30, 60, 40, 50, 70, 80). It also indicates PoE differential voltage, Mode A differential voltage, and Mode B differential voltage. The reference bar is connected to the generator return/earth and has points a, b, and c. + +**Figure A.15 – Power feed pair common mode to differential mode surge conversion test circuit** + +Figure A.16 shows a screen bonding test. + +![Circuit diagram for Figure A.16 showing a screen bonding test. It includes a 1.2/50-8/20 Generator, a resistor R9 (5 Ω), a double pole, three position selector switch (SW), an SPD, and a Reference bar. The diagram shows connections between cable ports (1-8) and equipment ports (10, 20, 30, 60, 40, 50, 70, 80). The switch (SW) is used to connect the generator return/earth to the reference bar. The reference bar is connected to the generator return/earth and has points a, b, and c.](b51423b6c049f5b5fcde42e50b58f18b_img.jpg) + +Circuit diagram for Figure A.16 showing a screen bonding test. It includes a 1.2/50-8/20 Generator, a resistor R9 (5 Ω), a double pole, three position selector switch (SW), an SPD, and a Reference bar. The diagram shows connections between cable ports (1-8) and equipment ports (10, 20, 30, 60, 40, 50, 70, 80). The switch (SW) is used to connect the generator return/earth to the reference bar. The reference bar is connected to the generator return/earth and has points a, b, and c. + +**Key** + +SW Double pole, three position selector switch R9 5 Ω + +**Figure A.16 – Screen bonding test** + +Figure A.17 shows a test circuit to measure the insulation resistance of an SPD with a PE terminal or screen terminals, or both. + +![Figure A.17: Test circuit to measure the insulation resistance of an SPD with a PE terminal or screen terminals, or both. The diagram shows an SPD with 'Cable port' terminals 1, 2, 3, 4, 5, 6, 7, 8 and 'Equipment port' terminals 10, 20, 30, 40, 50, 60, 70, 80. A 'PE' terminal and two 'Screen' terminals are also present. A 'Reference bar' is connected to the PE and Screen terminals. An IR meter (Ω) is connected via a four-position selector switch (SW) to the Cable port terminals. The switch has four positions labeled 1.2, 3.6, 7.8, and 4.5. The IR meter is connected to the Cable port terminals 1, 2, 3, 4, 5, 6, 7, 8. The PE terminal is connected to the Reference bar, which is connected to the IR meter. The Screen terminals are also connected to the Reference bar, which is connected to the IR meter.](85e2327652d513a7fee8fdbf97ad06f1_img.jpg) + +Figure A.17: Test circuit to measure the insulation resistance of an SPD with a PE terminal or screen terminals, or both. The diagram shows an SPD with 'Cable port' terminals 1, 2, 3, 4, 5, 6, 7, 8 and 'Equipment port' terminals 10, 20, 30, 40, 50, 60, 70, 80. A 'PE' terminal and two 'Screen' terminals are also present. A 'Reference bar' is connected to the PE and Screen terminals. An IR meter (Ω) is connected via a four-position selector switch (SW) to the Cable port terminals. The switch has four positions labeled 1.2, 3.6, 7.8, and 4.5. The IR meter is connected to the Cable port terminals 1, 2, 3, 4, 5, 6, 7, 8. The PE terminal is connected to the Reference bar, which is connected to the IR meter. The Screen terminals are also connected to the Reference bar, which is connected to the IR meter. + +##### **Key** + +SW Four position selector switch    Ω Insulation resistance (IR) meter with defined DC bias + +**Figure A.17 – Test circuit to measure the insulation resistance of an SPD with a PE terminal or screen terminals, or both** + +Figure A.18 shows a test circuit to measure the insulation resistance of an isolating transformer SPD without a PE terminal. + +![Figure A.18: Test circuit to measure the insulation resistance of an isolating transformer SPD without a PE terminal. The diagram shows an SPD with 'Cable port' terminals 1, 2, 3, 4, 5, 6, 7, 8 and 'Equipment port' terminals 10, 20, 30, 40, 50, 60, 70, 80. Two 'Screen' terminals are present. A 'Reference bar' is connected to the Screen terminals. An IR meter (Ω) is connected via a four-position selector switch (SW) to the Cable port terminals. The switch has four positions labeled 1.2, 3.6, 7.8, and 4.5. The IR meter is connected to the Cable port terminals 1, 2, 3, 4, 5, 6, 7, 8. The Screen terminals are connected to the Reference bar, which is connected to the IR meter.](a5b9392ecb96e6b5e0b4ee0664210f72_img.jpg) + +Figure A.18: Test circuit to measure the insulation resistance of an isolating transformer SPD without a PE terminal. The diagram shows an SPD with 'Cable port' terminals 1, 2, 3, 4, 5, 6, 7, 8 and 'Equipment port' terminals 10, 20, 30, 40, 50, 60, 70, 80. Two 'Screen' terminals are present. A 'Reference bar' is connected to the Screen terminals. An IR meter (Ω) is connected via a four-position selector switch (SW) to the Cable port terminals. The switch has four positions labeled 1.2, 3.6, 7.8, and 4.5. The IR meter is connected to the Cable port terminals 1, 2, 3, 4, 5, 6, 7, 8. The Screen terminals are connected to the Reference bar, which is connected to the IR meter. + +##### **Key** + +SW Four position selector switch    Ω IR meter with defined DC bias + +**Figure A.18 – Test circuit to measure the insulation resistance of an isolating transformer SPD without a PE terminal** + +Figure A.19 shows a test circuit to measure the PoE SPD DC input/output voltage drop. + +![Figure A.19: Test circuit to measure the PoE SPD DC input/output voltage drop. The diagram shows an SPD (Surge Protective Device) block with two sets of ports: 'Cable port' (terminals 1 through 8) and 'Equipment port' (terminals 1o through 8o). A 0.5 A current source is connected in parallel to the cable port side. Voltage measurements are indicated as V12 (between terminals 1 and 2), V36 (between 3 and 6), V45 (between 4 and 5), and V78 (between 7 and 8). On the equipment port side, terminals are paired and shorted: 1o-2o, 3o-6o, 4o-5o, and 7o-8o. At the bottom of the SPD block, there are terminals for 'Screen', 'PE' (Protective Earth), and another 'Screen'. The reference label K.147(23)_FA.19 is at the bottom right.](339be989b91d5b1e73e5ecdc8401ca75_img.jpg) + +Figure A.19: Test circuit to measure the PoE SPD DC input/output voltage drop. The diagram shows an SPD (Surge Protective Device) block with two sets of ports: 'Cable port' (terminals 1 through 8) and 'Equipment port' (terminals 1o through 8o). A 0.5 A current source is connected in parallel to the cable port side. Voltage measurements are indicated as V12 (between terminals 1 and 2), V36 (between 3 and 6), V45 (between 4 and 5), and V78 (between 7 and 8). On the equipment port side, terminals are paired and shorted: 1o-2o, 3o-6o, 4o-5o, and 7o-8o. At the bottom of the SPD block, there are terminals for 'Screen', 'PE' (Protective Earth), and another 'Screen'. The reference label K.147(23)\_FA.19 is at the bottom right. + +Figure A.19 – Test circuit to measure the PoE SPD DC input/output voltage drop + +### A.3 Testing of XDSL ports + +#### A.3.1 Test generators for external port testing + +##### A.3.1.1 Lightning surge generators + +Figure A.20 shows a 10/700 $\mu\text{s}$ voltage surge generator. + +![Figure A.20: 10/700 μs voltage surge generator circuit diagram. The circuit starts with a voltage source U_c connected to a capacitor C1 = 20 μF. A switch S1 connects this to the rest of the circuit. Following the switch is a parallel combination of a resistor R1 = 50 Ω and a capacitor C2 = 0.2 μF. A series resistor R2 = 15 Ω leads to a distribution network of current limit resistors, each labeled R. These resistors lead to output terminals g1, g2, ..., g1n, g2n. A common 'Return' line connects the bottom of the components back to the source. The reference label K.147(23)_FA.20 is at the bottom right.](315bdbeafb39026e19b77c26b19d9d1f_img.jpg) + +Figure A.20: 10/700 μs voltage surge generator circuit diagram. The circuit starts with a voltage source U\_c connected to a capacitor C1 = 20 μF. A switch S1 connects this to the rest of the circuit. Following the switch is a parallel combination of a resistor R1 = 50 Ω and a capacitor C2 = 0.2 μF. A series resistor R2 = 15 Ω leads to a distribution network of current limit resistors, each labeled R. These resistors lead to output terminals g1, g2, ..., g1n, g2n. A common 'Return' line connects the bottom of the components back to the source. The reference label K.147(23)\_FA.20 is at the bottom right. + +Figure A.20 – 10/700 $\mu\text{s}$ voltage surge generator from Figure A.3-1 of [ITU-T K.44] + +Figure A.21 shows output of 8/20 current generator. + +![Circuit diagram of a six-output 8/20 current generator. It features a switch connected to a 44.4 μF capacitor (C) and six parallel branches. Each branch contains an inductor (L1 through L6) in series with a resistor (R1 through R6), leading to outputs o1 through o6. All inductors are 9.7 μH and all resistors are 1.03 Ω. A common return line is also shown.](f57c7b37d7a05a99618104f390089f03_img.jpg) + +$C = 44.4 \mu\text{F}$ + $L1 = L2 = L3 = L4 = L5 = L6 = 9.7 \mu\text{H}$ + $R1 = R2 = R3 = R4 = R5 = R6 = 1.03 \Omega$ + +Return +K.147(23)\_FA.21 + +Circuit diagram of a six-output 8/20 current generator. It features a switch connected to a 44.4 μF capacitor (C) and six parallel branches. Each branch contains an inductor (L1 through L6) in series with a resistor (R1 through R6), leading to outputs o1 through o6. All inductors are 9.7 μH and all resistors are 1.03 Ω. A common return line is also shown. + +**Figure A.21 – Six output of 8/20 current generator Figure A.3-4 of [ITU-T K.44]** + +##### **A.3.1.2 AC generator** + +An AC generator is used for external port testing, as shown in Figure A.2. + +#### **A.3.2 Untested port termination and coupling network for external port testing** + +In order to couple the generator to the tested port, it is recommended that GDTs or MOVs according to Table A.5-1 of [ITU-T K.44], be used. + +Figure A.22 shows a decoupling network for AE connected to the tested external symmetric-pair port. + +![Circuit diagram of a decoupling network for auxiliary equipment (AE). The AE is connected to a network containing two 33 kΩ resistors, two 150 V gas discharge tubes (GDTs), and two 200 Ω resistors. The network is enclosed in a dashed box labeled 'Decoupling network'. The bottom line is labeled 'Generator return/Earth'.](6be06b7dc72bb42afcb3465394667c3b_img.jpg) + +Generator return/Earth +K.147(23)\_FA.22 + +Circuit diagram of a decoupling network for auxiliary equipment (AE). The AE is connected to a network containing two 33 kΩ resistors, two 150 V gas discharge tubes (GDTs), and two 200 Ω resistors. The network is enclosed in a dashed box labeled 'Decoupling network'. The bottom line is labeled 'Generator return/Earth'. + +**Figure A.22 – Decoupling network for AE connected to the tested external symmetric-pair port from Figure A.5-3 of [ITU-T K.44]** + +Figure A.23 shows the termination and coupling to earth of untested external symmetric-pair ports. + +![Circuit diagram (a) showing the termination of an untested external symmetric pair port. A dashed box labeled 'Decoupling network' contains two 200 Ω resistors in series with the input lines 'a' and 'b'. Each line has a 125 V clamping diode connected to the 'EUT reference bar'. Each line also has a 33 kΩ resistor connected to the 'Auxiliary equipment' terminals 'a' and 'b'. The 'EUT reference bar' is connected to the 'E' terminal of the 'Auxiliary equipment'.](e64c7b989e5bdb2708cd7aefd18b06e1_img.jpg) + +Circuit diagram (a) showing the termination of an untested external symmetric pair port. A dashed box labeled 'Decoupling network' contains two 200 Ω resistors in series with the input lines 'a' and 'b'. Each line has a 125 V clamping diode connected to the 'EUT reference bar'. Each line also has a 33 kΩ resistor connected to the 'Auxiliary equipment' terminals 'a' and 'b'. The 'EUT reference bar' is connected to the 'E' terminal of the 'Auxiliary equipment'. + +a) Termination of an untested external symmetric pair port + +![Circuit diagram (b) showing the coupling to earth and termination of an untested external symmetric pair port. It is similar to diagram (a) but includes a 'Coupling-to-earth element' (a circle with a ground symbol) connected between lines 'a' and 'b' and the 'Generator return/Earth'. The 'EUT reference bar' is also connected to the 'Generator return/Earth'.](02bb4edc0dbdf4f0749ffd3e0ea2805c_img.jpg) + +Circuit diagram (b) showing the coupling to earth and termination of an untested external symmetric pair port. It is similar to diagram (a) but includes a 'Coupling-to-earth element' (a circle with a ground symbol) connected between lines 'a' and 'b' and the 'Generator return/Earth'. The 'EUT reference bar' is also connected to the 'Generator return/Earth'. + +b) Coupling to earth and termination of an untested external symmetric pair port + +K.147(23)\_FA.23 + +**Figure A.23 – Termination and coupling to earth of untested external symmetric-pair ports from Figure A.5-10 of [ITU-T K.44]** + +Figure A.24 shows the termination and coupling to earth of untested external symmetric-pair ports. + +![Circuit diagram showing the connection of protection for the untested external symmetric-pair port. A dashed box labeled 'Protection for EUT' contains a circle with a ground symbol. The 'To EUT' line 'a' is connected to the top of the protection element, and line 'b' is connected to the bottom. The 'EUT reference bar' is connected to the bottom of the protection element. The 'To coupling-to-earth elements' line is also connected to the bottom of the protection element.](896e86ed12aff206d302c64f2e3091fa_img.jpg) + +Circuit diagram showing the connection of protection for the untested external symmetric-pair port. A dashed box labeled 'Protection for EUT' contains a circle with a ground symbol. The 'To EUT' line 'a' is connected to the top of the protection element, and line 'b' is connected to the bottom. The 'EUT reference bar' is connected to the bottom of the protection element. The 'To coupling-to-earth elements' line is also connected to the bottom of the protection element. + +K.147(23)\_FA.24 + +**Figure A.24 – Connection of protection for the untested external symmetric-pair port coupled to earth from Figure A.5-17 of [ITU-T K.44]** + +#### A.3.3 Differential-mode test circuits for external port + +Figure A.25 shows examples of test circuits for a transverse/differential overvoltage or overcurrent on a single external symmetric pair port for: terminal a to earth (Figure A.25a); and terminal b to earth (Figure A.25b). + +![Figure A.25a: Example of a test circuit for a transverse/differential overvoltage or overcurrent on a single external symmetric-pair port (a terminal to earth).](47a7beddcb8a1b7abdca746967e32bb4_img.jpg) + +The diagram illustrates a test circuit for terminal 'a' to earth. A 'Test generator' on the left has terminals O1 Output, O2, and Return. The Return is connected to 'Generator return/Earth' and ground. O1 Output connects to a 'Coupling element (See Table A.5-1)' within a larger block for 'Powering, auxiliary equipment or terminations as required and decoupling networks (See Figure A.5-3)'. This block connects to terminal 'a' of the EUT through a 'Special test protector'. Terminal 'b' of the EUT is connected to the 'EUT reference bar' through a resistor $R_1 = 0 \Omega$ unless otherwise specified. The EUT also has terminals a2, b2, and an Int./Ext. ports connection. A second 'Powering, auxiliary equipment or terminations...' block (See Figures A.5-10 to A.5-16) is connected to the EUT reference bar. The EUT reference bar is tied back to the Generator return/Earth. + +Figure A.25a: Example of a test circuit for a transverse/differential overvoltage or overcurrent on a single external symmetric-pair port (a terminal to earth). + +K.147(23)\_FA.25a + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +NOTE – The figures and table referenced in Figure 25a correspond to [ITU-T K.44]. + +**Figure A.25a – Example of a test circuit for a transverse/differential overvoltage or overcurrent on a single external symmetric-pair port (a terminal to earth) from Figure A.6.1-1a of [ITU-T K.44]** + +![Figure A.25b: Example of a test circuit for a transverse/differential overvoltage or overcurrent on a single external symmetric-pair port (b terminal to earth).](f1091147d93cee4dfa88498610e395a7_img.jpg) + +This diagram shows the test circuit for terminal 'b' to earth. It is identical in structure to Figure A.25a, except the 'Special test protector' and the active coupling path from the generator are now connected to terminal 'b' of the EUT. Consequently, terminal 'a' of the EUT is now the one connected to the 'EUT reference bar' through resistor $R_1 = 0 \Omega$ unless otherwise specified. The auxiliary powering/decoupling networks are adjusted to support the connection to terminal 'b'. + +Figure A.25b: Example of a test circuit for a transverse/differential overvoltage or overcurrent on a single external symmetric-pair port (b terminal to earth). + +K.147(23)\_FA.25b + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +NOTE – The figures and table referenced in Figure A.25b correspond to [ITU-T K.44]. + +**Figure 25b – Example of a test circuit for a transverse/differential overvoltage or overcurrent on a single external symmetric-pair port (b terminal to earth) from Figure A.6.1-1b of [ITU-T K.44]** + +#### A.3.4 Common-mode test circuits for external port + +Figure A.26 shows an example of a test circuit for an overvoltage or overcurrent on a single external symmetric-pair port to earth. + +![Figure A.26: Example of a test circuit for an overvoltage or overcurrent on a single external symmetric-pair port to earth. The diagram shows an 8/20 test generator connected to an AC source or 10/700 test generator. The output is connected to current limiting resistors (R) and then to a coupling element (See Table A.5-1). This is followed by a 'Powering, auxiliary equipment or terminations' block (See Figure A.5-3). A 'Special test protector, when required, for the test' is connected between the coupling element and the EUT. The EUT has an 'Internal port coupled to earth' and 'Ext. port' and 'Int./Ext. ports'. The EUT is connected to an 'EUT reference bar' and a 'Powering, auxiliary equipment or terminations' block (See Figures A.5-14 to A.5-16). The return path goes through the EUT reference bar to the 'Generator return/Earth'.](5eb69662cc4fa7d0d49b4eb22951c204_img.jpg) + +Figure A.26: Example of a test circuit for an overvoltage or overcurrent on a single external symmetric-pair port to earth. The diagram shows an 8/20 test generator connected to an AC source or 10/700 test generator. The output is connected to current limiting resistors (R) and then to a coupling element (See Table A.5-1). This is followed by a 'Powering, auxiliary equipment or terminations' block (See Figure A.5-3). A 'Special test protector, when required, for the test' is connected between the coupling element and the EUT. The EUT has an 'Internal port coupled to earth' and 'Ext. port' and 'Int./Ext. ports'. The EUT is connected to an 'EUT reference bar' and a 'Powering, auxiliary equipment or terminations' block (See Figures A.5-14 to A.5-16). The return path goes through the EUT reference bar to the 'Generator return/Earth'. + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +NOTE – The figures and tables referenced in Figure A.26 correspond to [ITU-T K.44]. + +**Figure A.26 – Example of a test circuit for an overvoltage or overcurrent on a single external symmetric-pair port to earth from Figure A.6.1-2 of [ITU-T K.44]** + +Figure A.27 shows an example of a test circuit for an overvoltage or overcurrent on an external multiple symmetric-pair port, external multiple symmetric-pair ports or a combination of both, to earth. + +![Figure A.27: Example of a test circuit for an overvoltage or overcurrent on an external multiple symmetric-pair port, external multiple symmetric-pair ports or a combination of both, to earth. The diagram is similar to Figure A.26 but features multiple 'Current limiting resistors' (R) connected to multiple 'Coupling element' blocks (See Table A.5-1). These are followed by multiple 'Powering, auxiliary equipment or terminations' blocks (See Figure A.5-3). An 'Agreed primary protector when required for the test' is connected between the coupling elements and the EUT. The EUT has an 'Internal port coupled to earth' and 'Ext. port' and 'Int./Ext. ports'. The EUT is connected to an 'EUT reference bar' and a 'Powering, auxiliary equipment or terminations' block (See Figures A.5-14 to A.5-16). The return path goes through the EUT reference bar to the 'Generator return/Earth'.](107da2e3495b2f24352c9e3b26ec4841_img.jpg) + +Figure A.27: Example of a test circuit for an overvoltage or overcurrent on an external multiple symmetric-pair port, external multiple symmetric-pair ports or a combination of both, to earth. The diagram is similar to Figure A.26 but features multiple 'Current limiting resistors' (R) connected to multiple 'Coupling element' blocks (See Table A.5-1). These are followed by multiple 'Powering, auxiliary equipment or terminations' blocks (See Figure A.5-3). An 'Agreed primary protector when required for the test' is connected between the coupling elements and the EUT. The EUT has an 'Internal port coupled to earth' and 'Ext. port' and 'Int./Ext. ports'. The EUT is connected to an 'EUT reference bar' and a 'Powering, auxiliary equipment or terminations' block (See Figures A.5-14 to A.5-16). The return path goes through the EUT reference bar to the 'Generator return/Earth'. + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +NOTE – The figures and tables referenced in Figure A.27 correspond to [ITU-T K.44]. + +**Figure A.27 – Example of a test circuit for an overvoltage or overcurrent on an external multiple symmetric-pair port, external multiple symmetric-pair ports or a combination of both, to earth from Figure A.6.1-4 of [ITU-T K.44]** + +#### A.3.5 External port to another external port + +Figure A.28 shows an example of a test circuit for an overvoltage or overcurrent on a single external symmetric-pair port to another external. + +![Figure A.28: Example of a test circuit for an overvoltage or overcurrent on a single external symmetric-pair port to another external. The diagram shows a test setup where an 8/20 test generator and an AC source or 10/700 test generator are connected to a coupling element. This is followed by a special test protector, the Equipment Under Test (EUT), and another coupling element leading to the EUT reference bar. Various components like 'Appropriate primary protection, or special test protector' and 'Powering, auxiliary equipment or terminations' are also shown. The diagram is labeled K.147(23)_FA.28.](95e259e8cb3519025066052af263f8c0_img.jpg) + +Figure A.28: Example of a test circuit for an overvoltage or overcurrent on a single external symmetric-pair port to another external. The diagram shows a test setup where an 8/20 test generator and an AC source or 10/700 test generator are connected to a coupling element. This is followed by a special test protector, the Equipment Under Test (EUT), and another coupling element leading to the EUT reference bar. Various components like 'Appropriate primary protection, or special test protector' and 'Powering, auxiliary equipment or terminations' are also shown. The diagram is labeled K.147(23)\_FA.28. + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +NOTE – The figures and table referenced in Figure A.28 correspond to [ITU-T K.44]. + +**Figure A.28 – Example of a test circuit for an overvoltage or overcurrent on a single external symmetric-pair port to another external port from Figure A.6.1-3 of [ITU-T K.44]** + +Figure A.29 shows an example of test circuit for an overvoltage or overcurrent on an external multiple symmetric-pair port, external multiple symmetric-pair ports or a combination of both, to another external port. + +![Figure A.29: Example of test circuit for an overvoltage or overcurrent on an external multiple symmetric-pair port, external multiple symmetric-pair ports or a combination of both, to another external port. This diagram is more complex than A.28, showing multiple symmetric-pair ports (O1, O2, O3, O4, O5, O6) connected through current limiting resistors (R) to a coupling element. It includes similar components to Figure A.28: AC source, special test protector, EUT, and EUT reference bar. The diagram is labeled K.147(23)_FA.29.](4669a2ca9d019b9c2de9a9d9a0c4e644_img.jpg) + +Figure A.29: Example of test circuit for an overvoltage or overcurrent on an external multiple symmetric-pair port, external multiple symmetric-pair ports or a combination of both, to another external port. This diagram is more complex than A.28, showing multiple symmetric-pair ports (O1, O2, O3, O4, O5, O6) connected through current limiting resistors (R) to a coupling element. It includes similar components to Figure A.28: AC source, special test protector, EUT, and EUT reference bar. The diagram is labeled K.147(23)\_FA.29. + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +NOTE – The figures and table referenced in Figure A.29 correspond to [ITU-T K.44]. + +**Figure A.29 – Example of test circuit for an overvoltage or overcurrent on an external multiple symmetric-pair port, external multiple symmetric pair ports or a combination of both, to another external port from Figure A.6.1-5 of [ITU-T K.44]** + +#### A.3.6 Test generators for internal port testing + +Combination wave generator is used for this internal port testing shown in clause A.2.1.1 as Figure A.1. + +#### A.3.7 Untested port termination and coupling network for internal port testing + +In order to couple the generator to tested port, it is recommended to use GDTs or MOVs according to Table A.5-1 of [ITU-T K.44]. + +Figure A.30 shows a decoupling network for AE connected to the tested internal unshielded cable port. + +![Circuit diagram of a decoupling network for auxiliary equipment (AE) connected to tested internal unshielded cable ports. The diagram shows two sets of ports: (a, b) and (a_n, b_n). Each port pair is connected to the AE through a 200 Ω resistor. A 33 kΩ resistor and an 18 V clamping diode are connected in parallel between each port pair and the common return/earth line. The AE is connected to the common return/earth line at point E. The decoupling network is enclosed in a dashed box labeled 'Decoupling network'. The diagram is labeled K.147(23)_FA.30.](e05122559f56af5699789b7118d8fe87_img.jpg) + +The diagram illustrates a decoupling network for auxiliary equipment (AE) connected to tested internal unshielded cable ports. The network is enclosed in a dashed box labeled "Decoupling network". + +On the left, the "Auxiliary equipment" is shown with terminals labeled a, b, an, bn, and E (Generator return/Earth). The terminals a and b are connected to the network via 200 Ω resistors. The terminals an and bn are also connected to the network via 200 Ω resistors. The terminal E is connected to the common return/earth line. + +Inside the decoupling network, for each pair of terminals (a, b) and (an, bn), there is a 33 kΩ resistor and an 18 V clamping diode connected in parallel between the respective port lines and the common return/earth line. The 18 V clamping diodes are oriented with their cathodes towards the port lines. + +The common return/earth line is connected to the terminal E of the auxiliary equipment and is labeled "Generator return/Earth" at the bottom right. The diagram is identified by the code K.147(23)\_FA.30. + +Circuit diagram of a decoupling network for auxiliary equipment (AE) connected to tested internal unshielded cable ports. The diagram shows two sets of ports: (a, b) and (a\_n, b\_n). Each port pair is connected to the AE through a 200 Ω resistor. A 33 kΩ resistor and an 18 V clamping diode are connected in parallel between each port pair and the common return/earth line. The AE is connected to the common return/earth line at point E. The decoupling network is enclosed in a dashed box labeled 'Decoupling network'. The diagram is labeled K.147(23)\_FA.30. + +**Figure A.30 – Decoupling network for AE connected to the tested internal unshielded cable port from Figure A.6.5-7 of [ITU-T K.44]** + +Figure A.31 shows the termination of untested internal symmetric-pair ports. + +![Circuit diagram of a decoupling network for terminating untested internal symmetric pair ports. The diagram shows four signal lines (a, b, a_n, b_n) entering a 'Decoupling network' (dashed box) and exiting to 'Auxiliary equipment'. Each line passes through a 200 Ω resistor. After the resistor, each line is connected to an 18 V clamping diode and a 33 kΩ resistor in parallel. The other ends of the clamping diodes and 33 kΩ resistors are connected to a common 'EUT reference bar'. The auxiliary equipment is also connected to this reference bar at point 'E'. The diagram is labeled K.147(23)_FA.31.](798679874d1c29f8343506a156c79d7e_img.jpg) + +The diagram illustrates a decoupling network used for terminating untested internal symmetric pair ports. It consists of four signal lines, labeled a, b, an, and bn. Each line enters a 'Decoupling network' (indicated by a dashed box). Inside the network, each line has a 200 Ω resistor in series. Following the resistor, each line has a branch containing an 18 V clamping diode and another branch containing a 33 kΩ resistor. These parallel branches connect to a common 'EUT reference bar'. The lines then exit the decoupling network to 'Auxiliary equipment'. The auxiliary equipment is also connected to the EUT reference bar at a terminal labeled 'E'. The diagram is identified as K.147(23)\_FA.31. + +Circuit diagram of a decoupling network for terminating untested internal symmetric pair ports. The diagram shows four signal lines (a, b, a\_n, b\_n) entering a 'Decoupling network' (dashed box) and exiting to 'Auxiliary equipment'. Each line passes through a 200 Ω resistor. After the resistor, each line is connected to an 18 V clamping diode and a 33 kΩ resistor in parallel. The other ends of the clamping diodes and 33 kΩ resistors are connected to a common 'EUT reference bar'. The auxiliary equipment is also connected to this reference bar at point 'E'. The diagram is labeled K.147(23)\_FA.31. + +**Figure A.31 – Termination of untested internal symmetric pair ports from Figure A.5-14a of [ITU-T K.44]** + +Figure A.32 shows coupling to earth and termination of untested internal symmetric-pair ports. + +![Figure A.32: Coupling to earth and termination of untested internal symmetric pair ports. The diagram shows a 'Decoupling network' (dashed box) connected to 'Auxiliary equipment' (solid box). On the left, five 'Coupling-to-earth element' blocks are shown, each containing a '18 V clamping diode'. These are connected to terminals a, b, a_n, b_n, and a common 'Generator return/Earth' line. Inside the 'Decoupling network', each line has a '200 Ω' resistor in series and a '18 V clamping diode' in shunt to the common line. On the right side of the network, each line has a '33 kΩ' resistor in shunt to the common line before entering the 'Auxiliary equipment' at terminals a, b, a_n, b_n. The 'Auxiliary equipment' also has an 'E' (Earth) terminal. The diagram is labeled K.147(23)_FA.32.](cbb2d311b20781a595488445ded48d0a_img.jpg) + +Figure A.32: Coupling to earth and termination of untested internal symmetric pair ports. The diagram shows a 'Decoupling network' (dashed box) connected to 'Auxiliary equipment' (solid box). On the left, five 'Coupling-to-earth element' blocks are shown, each containing a '18 V clamping diode'. These are connected to terminals a, b, a\_n, b\_n, and a common 'Generator return/Earth' line. Inside the 'Decoupling network', each line has a '200 Ω' resistor in series and a '18 V clamping diode' in shunt to the common line. On the right side of the network, each line has a '33 kΩ' resistor in shunt to the common line before entering the 'Auxiliary equipment' at terminals a, b, a\_n, b\_n. The 'Auxiliary equipment' also has an 'E' (Earth) terminal. The diagram is labeled K.147(23)\_FA.32. + +**Figure A.32 – Coupling to earth and termination of untested internal symmetric pair ports from Figure A.5-14b of [ITU-T K.44]** + +#### **A.3.8 Common-mode test circuits for internal port** + +Figure A.33 shows an example of test circuit for an overvoltage or overcurrent on an internal port connected to an unshielded cable with single or multiple symmetric pairs to earth. + +![Figure A.33: Example of test circuit for an overvoltage or overcurrent on an internal port. The diagram shows a 'Test generator' with 'Output' and 'Return' terminals connected to 'Current limiting resistors' (R). These resistors are connected to the 'Powering, auxiliary equipment or terminations as required and decoupling networks' (See Figure A.5-7) at terminals a, b, a_n, b_n, and E. The 'E' terminal is connected to 'Generator return/Earth'. The 'Powering, auxiliary equipment or terminations' are also connected to 'Coupling element (See Table A.5-1)' blocks. These blocks are connected to the 'Internal port coupled to earth' (Int. port) of the 'EUT and terminations'. The 'EUT and terminations' have 'Int./Ext. ports' (a, b, a_n, b_n) connected to another 'Powering, auxiliary equipment or terminations, as required, and decoupling networks' (See Figures A.5-14-A.5-16). This second network is connected to the 'EUT reference bar' and 'E' (Earth). The 'EUT reference bar' is connected to the 'Generator return/Earth'. The diagram is labeled K.147(23)_FA.33.](cf8bd014a50b7c69435e804f67f9617f_img.jpg) + +Figure A.33: Example of test circuit for an overvoltage or overcurrent on an internal port. The diagram shows a 'Test generator' with 'Output' and 'Return' terminals connected to 'Current limiting resistors' (R). These resistors are connected to the 'Powering, auxiliary equipment or terminations as required and decoupling networks' (See Figure A.5-7) at terminals a, b, a\_n, b\_n, and E. The 'E' terminal is connected to 'Generator return/Earth'. The 'Powering, auxiliary equipment or terminations' are also connected to 'Coupling element (See Table A.5-1)' blocks. These blocks are connected to the 'Internal port coupled to earth' (Int. port) of the 'EUT and terminations'. The 'EUT and terminations' have 'Int./Ext. ports' (a, b, a\_n, b\_n) connected to another 'Powering, auxiliary equipment or terminations, as required, and decoupling networks' (See Figures A.5-14-A.5-16). This second network is connected to the 'EUT reference bar' and 'E' (Earth). The 'EUT reference bar' is connected to the 'Generator return/Earth'. The diagram is labeled K.147(23)\_FA.33. + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +NOTE – The figures and table referenced in Figure A.33 correspond to [ITU-T K.44]. + +**Figure A.33 – Example of test circuit for an overvoltage or overcurrent on an internal port connected to an unshielded cable with single or multiple symmetric pairs to earth from Figure A.6.5-1 of [ITU-T K.44]** + +Figure A.34 shows an example of a test circuit for an overvoltage or overcurrent on an internal port connected to a shielded cable to earth. + +![Figure A.34: Example of a test circuit for an overvoltage or overcurrent on an internal port connected to a shielded cable to earth. The diagram shows a test generator connected to current limiting resistors (R) and a coupling element (See Table A.5-1). A shielded cable of length L = 20 m connects the coupling element to the EUT (Equipment Under Test). The EUT has internal ports (1 to n) and an internal port coupled to earth. The EUT is connected to a powering, auxiliary equipment or termination network (See Figures A.5-10-A.5-16) and an EUT reference bar. The EUT reference bar is connected to the generator return/Earth. The diagram also shows the EUT reference bar connected to the powering, auxiliary equipment or termination network.](878d9539700bd792e7d12ad6f1203c5d_img.jpg) + +Figure A.34: Example of a test circuit for an overvoltage or overcurrent on an internal port connected to a shielded cable to earth. The diagram shows a test generator connected to current limiting resistors (R) and a coupling element (See Table A.5-1). A shielded cable of length L = 20 m connects the coupling element to the EUT (Equipment Under Test). The EUT has internal ports (1 to n) and an internal port coupled to earth. The EUT is connected to a powering, auxiliary equipment or termination network (See Figures A.5-10-A.5-16) and an EUT reference bar. The EUT reference bar is connected to the generator return/Earth. The diagram also shows the EUT reference bar connected to the powering, auxiliary equipment or termination network. + +For repeatability of measurement, it is recommended that the test be performed on an earth reference plane, with the cable laid on the ground plane in a snake pattern. All conductors are connected together and with the shield. (Reason: in worst case, inserted protective elements in the auxiliary equipment – not included in this test set-up – can cause short circuit termination.) + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +NOTE – The figures and table referenced in Figure A.34 correspond to [ITU-T K.44]. + +**Figure A.34 – Example of a test circuit for an overvoltage or overcurrent on an internal port connected to a shielded cable to earth from Figure A.6.5-2 of [ITU-T K.44]** + +#### A.3.9 Differential-mode test circuits for internal port + +The test circuit shown in Figure A.9 is used also for this differential-mode testing as a "twisted pair transverse/differential surge test circuit for ports having one for internal port". + +# Appendix I + +## Examples of Ethernet twisted pair DC power feeds + +(This appendix does not form an integral part of this Recommendation.) + +## I.1 Introduction + +This appendix provides a rough sketch of the circuit configuration of Ethernet twisted-pair DC power feeds for the application of the overvoltage and overcurrent test procedures in [ITU-T K.44], [ITU-T K.20], [ITU-T K.21], [ITU-T K.45] and [ITU-T K.117], based on the circuit surge propagation. + +This appendix summarizes the DC power feed circuits listed in Table I.1 of [b-IEEE 802.3]. + +Note that Figures I.1 to I.10 are based on those in [b-IEEE 802.3], and alignment with the ISO/IEC JTC1/SC25 vocabulary. + +**Table I.1 – DC power feed circuits** + +| Figure | Ethernet data rate | Powering pairs | Powering pair configuration | Injector | +|--------|---------------------|----------------|-----------------------------|----------| +| I.1 | 100 Mb/s to 10 Gb/s | 1 | C1 | | +| I.2 | 10 Mb/s | 1 | C1 | | +| I.3 | 10 Mb/s & 100 Mb/s | 2 | C1 or C2 | | +| I.4 | $\geq 1\,000$ Mb/s | 2 | C1 | | +| I.5 | 10 Mb/s & 100 Mb/s | 2 | C1 or C2 | Yes | +| I.6 | $\geq 1\,000$ Mb/s | 2 | C1 | Yes | +| I.7 | 10 Mb/s & 100 Mb/s | 4 | C1 and C2 | | +| I.8 | $\geq 1\,000$ Mb/s | 4 | C1 | | +| I.9 | 10 Mb/s & 100 Mb/s | 4 | C1 and C2 | Yes | +| I.10 | $\geq 1\,000$ Mb/s | 4 | C1 | Yes | + +C1: Power and data on same pair; C2: power and data in separate pairs + +## I.2 Powering over one twisted pair + +In this case, both power and data share the same twisted pair, as shown in Figures I.1 and I.2. + +![Figure I.1 – Generic single twisted-pair RP system block diagram. The diagram shows a Power source equipment (PSE) on the left and a Network powered device (NPD) on the right, connected by a single twisted-pair cable. The PSE contains a 'Power source' block and a 'Data' block, each connected to a transformer. The secondary of the power transformer is connected to pins 1 and 2 of the cable. The secondary of the data transformer is also connected to pins 1 and 2 of the cable. The NPD contains a 'Power conversion' block and a 'Data' block, each connected to a transformer. The primary of the power transformer is connected to pins 1 and 2 of the cable. The primary of the data transformer is also connected to pins 1 and 2 of the cable. The cable itself is shown as a twisted line with two conductors. The diagram is labeled K.147(23)_FI.1.](4767b6e106f34fe8b63a6838810bf913_img.jpg) + +Figure I.1 – Generic single twisted-pair RP system block diagram. The diagram shows a Power source equipment (PSE) on the left and a Network powered device (NPD) on the right, connected by a single twisted-pair cable. The PSE contains a 'Power source' block and a 'Data' block, each connected to a transformer. The secondary of the power transformer is connected to pins 1 and 2 of the cable. The secondary of the data transformer is also connected to pins 1 and 2 of the cable. The NPD contains a 'Power conversion' block and a 'Data' block, each connected to a transformer. The primary of the power transformer is connected to pins 1 and 2 of the cable. The primary of the data transformer is also connected to pins 1 and 2 of the cable. The cable itself is shown as a twisted line with two conductors. The diagram is labeled K.147(23)\_FI.1. + +**Figure I.1 – Generic single twisted-pair RP system block diagram** + +![Figure I.2: 10 Mb/s long reach (1 km or more) single twisted-pair RP system block diagram. The diagram shows a Power source equipment (PSE) on the left and a Network powered device (NPD) on the right connected by a single twisted-pair cable. The PSE contains a 'Power source' block connected to a transformer, and a 'Data' block connected to another transformer. The NPD contains a 'Power conversion' block connected to a transformer, and a 'Data' block connected to another transformer. The cable has two conductors labeled 1 and 2 at the PSE end, and 1 or 2 and 2 or 1 at the NPD end. The diagram is labeled K.147(23)_FI.2.](c1df61cc3717e878a48e530218403403_img.jpg) + +Figure I.2: 10 Mb/s long reach (1 km or more) single twisted-pair RP system block diagram. The diagram shows a Power source equipment (PSE) on the left and a Network powered device (NPD) on the right connected by a single twisted-pair cable. The PSE contains a 'Power source' block connected to a transformer, and a 'Data' block connected to another transformer. The NPD contains a 'Power conversion' block connected to a transformer, and a 'Data' block connected to another transformer. The cable has two conductors labeled 1 and 2 at the PSE end, and 1 or 2 and 2 or 1 at the NPD end. The diagram is labeled K.147(23)\_FI.2. + +**Figure I.2 – 10 Mb/s long reach (1 km or more) single twisted-pair RP system block diagram (based on Figure 104-3 of [b-IEEE 802.3])** + +## I.3 Powering over two twisted pairs + +In this case, powering uses two twisted pairs, one for feed and the other for the return. These may be shared with data in the alternative A configuration or be separate in the alternative B configuration, as shown in Figures I.3, I.4, I.5 and I.6. + +![Figure I.3: 10 Mb/s and 100 Mb/s PoE alternatives A and B. The diagram is split into two parts. The left part, labeled 'Alternative A', shows a Power source equipment (PSE) on the left and a Network powered device (NPD) on the right. The PSE has a 'Power source' block connected to a transformer, and a 'Data' block connected to another transformer. The NPD has a 'Power conversion' block connected to a transformer, and a 'Data' block connected to another transformer. The cable has four conductors labeled 1, 2, 3, 4, 5, 6, 7, 8. The PSE has 'Data terminals all' and 'Power terminals 1+2/3+6'. The NPD has 'Data terminals all' and 'Power terminals 1+2/3+6'. The right part, labeled 'Alternative B', shows a Power source equipment (PSE) on the left and a Network powered device (NPD) on the right. The PSE has a 'Power source' block connected to a transformer, and a 'Data' block connected to another transformer. The NPD has a 'Power conversion' block connected to a transformer, and a 'Data' block connected to another transformer. The cable has four conductors labeled 1, 2, 3, 4, 5, 6, 7, 8. The PSE has 'Data terminals all' and 'Power terminals 4+5/7+8'. The NPD has 'Data terminals all' and 'Power terminals 4+5/7+8'. The diagram is labeled K.147(23)_FI.3.](036ceaf207a7b289ca76e160892eb724_img.jpg) + +Figure I.3: 10 Mb/s and 100 Mb/s PoE alternatives A and B. The diagram is split into two parts. The left part, labeled 'Alternative A', shows a Power source equipment (PSE) on the left and a Network powered device (NPD) on the right. The PSE has a 'Power source' block connected to a transformer, and a 'Data' block connected to another transformer. The NPD has a 'Power conversion' block connected to a transformer, and a 'Data' block connected to another transformer. The cable has four conductors labeled 1, 2, 3, 4, 5, 6, 7, 8. The PSE has 'Data terminals all' and 'Power terminals 1+2/3+6'. The NPD has 'Data terminals all' and 'Power terminals 1+2/3+6'. The right part, labeled 'Alternative B', shows a Power source equipment (PSE) on the left and a Network powered device (NPD) on the right. The PSE has a 'Power source' block connected to a transformer, and a 'Data' block connected to another transformer. The NPD has a 'Power conversion' block connected to a transformer, and a 'Data' block connected to another transformer. The cable has four conductors labeled 1, 2, 3, 4, 5, 6, 7, 8. The PSE has 'Data terminals all' and 'Power terminals 4+5/7+8'. The NPD has 'Data terminals all' and 'Power terminals 4+5/7+8'. The diagram is labeled K.147(23)\_FI.3. + +**Figure I.3 – 10 Mb/s and 100 Mb/s PoE alternatives A and B (based on Figure 33-4 and Figure 145-4 of [b-IEEE 802.3])** + +![Figure I.4: ≥1 000 Mb/s PoE alternatives A and B. Two diagrams showing Power source equipment (PSE) and Network powered device (NPD) connections. Alternative A uses terminals 1+2/3+6 for power, while Alternative B uses 4+5/7+8.](38cbce07f83fba6d5a7c46605bd5743f_img.jpg) + +Figure I.4 shows two diagrams for $\geq 1\,000$ Mb/s PoE alternatives. Both diagrams show a Power source equipment (PSE) on the left and a Network powered device (NPD) on the right, connected by four twisted-pair cables. Each cable has two data pairs, labeled 1-2, 3-6, 4-5, and 7-8. In Alternative A, the PSE is connected to a Power source and has power terminals 1+2/3+6. The NPD has data terminals all and power terminals 1+2/3+6. In Alternative B, the PSE is connected to a Power source and has power terminals 4+5/7+8. The NPD has data terminals all and power terminals 4+5/7+8. Both diagrams include a 'Power conversion' block within the NPD. + +Figure I.4: ≥1 000 Mb/s PoE alternatives A and B. Two diagrams showing Power source equipment (PSE) and Network powered device (NPD) connections. Alternative A uses terminals 1+2/3+6 for power, while Alternative B uses 4+5/7+8. + +**Figure I.4 – $\geq 1\,000$ Mb/s PoE alternatives A and B (based on Figure 33-5 and Figure 145-5 of [b-IEEE 802.3])** + +![Figure I.5: 10 Mb/s and 100 Mb/s PoE injector alternatives A and B. Two diagrams showing Ethernet equipment, (PoE) injector power source equipment (PSE), and Network powered device (NPD) connections. Alternative A uses terminals 1+2/3+6 for power, while Alternative B uses 4+5/7+8.](ec3647789b5c38fb686f2a0833324e79_img.jpg) + +Figure I.5 shows two diagrams for 10 Mb/s and 100 Mb/s PoE injector alternatives. Both diagrams show Ethernet equipment on the left, a (PoE) injector power source equipment (PSE) in the middle, and a Network powered device (NPD) on the right. The PSE is connected to a Power source. In Alternative A, the PSE has power terminals 1+2/3+6, and the NPD has data terminals 1 & 2/3 & 6 and power terminals 1+2/3+6. In Alternative B, the PSE has power terminals 4+5/7+8, and the NPD has data terminals 1 & 2/3 & 6 and power terminals 4+5/7+8. Both diagrams include a 'Power conversion' block within the NPD. + +Figure I.5: 10 Mb/s and 100 Mb/s PoE injector alternatives A and B. Two diagrams showing Ethernet equipment, (PoE) injector power source equipment (PSE), and Network powered device (NPD) connections. Alternative A uses terminals 1+2/3+6 for power, while Alternative B uses 4+5/7+8. + +**Figure I.5 – 10 Mb/s and 100 Mb/s PoE injector alternatives A and B (based on Figure 33-6 and Figure 145-9 of [b-IEEE 802.3])** + +![Figure I.6: 1 000 Mb/s PoE injector alternatives A and B. Two diagrams showing Ethernet equipment, (PoE) injector power source equipment (PSE), and Network powered device (NPD) connections. Alternative A uses terminals 1+2/3+6 for power, while Alternative B uses 4+5/7+8.](7fe5741e83bc9702d1b1d7585ddf66bd_img.jpg) + +Figure I.6 shows two diagrams for 1 000 Mb/s PoE injector alternatives. Both diagrams show Ethernet equipment on the left, a (PoE) injector power source equipment (PSE) in the middle, and a Network powered device (NPD) on the right. The PSE is connected to a Power source. In Alternative A, the PSE has power terminals 1+2/3+6, and the NPD has data terminals all and power terminals 1+2/3+6. In Alternative B, the PSE has power terminals 4+5/7+8, and the NPD has data terminals all and power terminals 4+5/7+8. Both diagrams include a 'Power conversion' block within the NPD. + +Figure I.6: 1 000 Mb/s PoE injector alternatives A and B. Two diagrams showing Ethernet equipment, (PoE) injector power source equipment (PSE), and Network powered device (NPD) connections. Alternative A uses terminals 1+2/3+6 for power, while Alternative B uses 4+5/7+8. + +**Figure I.6 – 1 000 Mb/s PoE injector alternatives A and B (based on Figure 33-7 and Figure 145-8 of [b-IEEE 802.3])** + +## I.4 Powering over four twisted pairs + +In this case, powering uses four twisted pairs, two for feed and two for return, as shown in Figures I.7, I.8, I.9 and I.10. + +![Diagram of 10 Mb/s and 100 Mb/s PoE showing a Power source equipment (PSE) connected to a Network powered device (NPD) via four twisted pairs. The PSE uses terminals 1, 2, 3, and 6 for data, and 4, 5, 7, and 8 for power. The NPD uses terminals 1, 2, 3, and 6 for data, and 4, 5, 7, 8, 3, and 6 for power.](01e00200a536673d6cd0e6d8705047a0_img.jpg) + +Power source equipment (PSE) + +Data pair (pins 1, 2) + +Data pair (pins 3, 6) + +Pair (pins 4, 5) + +Pair (pins 7, 8) + +Data terminals 1 & 2/3 & 6 +Power terminals 1+2/4+5/7+8/3+6 + +Power source + +Network powered device (NPD) + +Data pair (pins 1, 2) + +Data pair (pins 3, 6) + +Pair (pins 4, 5) + +Pair (pins 7, 8) + +Data terminals 1 & 2/3 & 6 +Power terminals 1+2/4+5/7+8/3+6 + +Power conversion + +K.147(23)\_FI.7 + +Diagram of 10 Mb/s and 100 Mb/s PoE showing a Power source equipment (PSE) connected to a Network powered device (NPD) via four twisted pairs. The PSE uses terminals 1, 2, 3, and 6 for data, and 4, 5, 7, and 8 for power. The NPD uses terminals 1, 2, 3, and 6 for data, and 4, 5, 7, 8, 3, and 6 for power. + +**Figure I.7 – 10 Mb/s and 100 Mb/s PoE (based on Figure 145-6 of [b-IEEE 802.3])** + +![Diagram of 1/2.5/5/10 Gb/s PoE showing a Power source equipment (PSE) connected to a Network powered device (NPD) via four twisted pairs. The PSE uses all eight terminals for data, and 1, 2, 4, 5, 7, 8, 3, and 6 for power. The NPD uses all eight terminals for data, and 1, 2, 4, 5, 7, 8, 3, and 6 for power.](0f1767577a073167eb9628d72034e083_img.jpg) + +Power source equipment (PSE) + +Data pair (pins 1, 2) + +Data pair (pins 3, 6) + +Data pair (pins 4, 5) + +Data pair (pins 7, 8) + +Data terminals all +Power terminals 1+2/4+5/7+8/3+6 + +Power source + +Network powered device (NPD) + +Data pair (pins 1, 2) + +Data pair (pins 3, 6) + +Data pair (pins 4, 5) + +Data pair (pins 7, 8) + +Data terminals all +Power terminals 1+2/4+5/7+8/3+6 + +Power conversion + +K.147(23)\_FI.8 + +Diagram of 1/2.5/5/10 Gb/s PoE showing a Power source equipment (PSE) connected to a Network powered device (NPD) via four twisted pairs. The PSE uses all eight terminals for data, and 1, 2, 4, 5, 7, 8, 3, and 6 for power. The NPD uses all eight terminals for data, and 1, 2, 4, 5, 7, 8, 3, and 6 for power. + +**Figure I.8 – 1/2.5/5/10 Gb/s PoE (based on Figure 145-7 of [b-IEEE 802.3])** + +![Diagram of a 10 Mb/s and 100 Mb/s PoE injector (PSE) connected to Ethernet equipment and a Network powered device (NPD).](5ee1bbbf85b473f78af9ec8368a4159a_img.jpg) + +This diagram illustrates the internal architecture of a 10 Mb/s and 100 Mb/s PoE injector. It shows three main components: **Ethernet equipment** on the left, a **(PoE) injector power source equipment (PSE)** in the center, and a **Network powered device (NPD)** on the right. The Ethernet equipment has 8 data terminals, with data pairs connected to terminals 1 & 2, 3 & 6, 4 & 5, and 7 & 8. The PSE receives data from the Ethernet equipment and adds power. It has a **Power source** connected to its power terminals (1+2/4+5/7+8/3+6). The PSE's data terminals are connected to the NPD. The NPD has a **Power conversion** block that extracts the power from the data lines. The NPD's data terminals are also 1 & 2/3 & 6, and its power terminals are 1+2/4+5/7+8/3+6. The diagram is labeled K.147(23)\_Fl.9. + +Diagram of a 10 Mb/s and 100 Mb/s PoE injector (PSE) connected to Ethernet equipment and a Network powered device (NPD). + +**Figure I.9 – 10 Mb/s and 100 Mb/s PoE injector (based on Figure 145-10 of [b-IEEE 802.3])** + +![Diagram of a 1/2.5/5/10 Gb/s PoE injector (PSE) connected to Ethernet equipment and a Network powered device (NPD).](8f7c0bf0c75a31fee6b0c7392ff57c39_img.jpg) + +This diagram illustrates the internal architecture of a 1/2.5/5/10 Gb/s PoE injector. It shows three main components: **Ethernet equipment** on the left, a **(PoE) injector power source equipment (PSE)** in the center, and a **Network powered device (NPD)** on the right. The Ethernet equipment has 8 data terminals, with data pairs connected to terminals 1 & 2, 3 & 6, 4 & 5, and 7 & 8. The PSE receives data from the Ethernet equipment and adds power. It has a **Power source** connected to its power terminals (1+2/4+5/7+8/3+6). The PSE's data terminals are connected to the NPD. The NPD has a **Power conversion** block that extracts the power from the data lines. The NPD's data terminals are all 8, and its power terminals are 1+2/4+5/7+8/3+6. The diagram is labeled K.147(23)\_Fl.10. + +Diagram of a 1/2.5/5/10 Gb/s PoE injector (PSE) connected to Ethernet equipment and a Network powered device (NPD). + +**Figure I.10 – 1/2.5/5/10 Gb/s PoE injector (based on Figure 145-11 of [b-IEEE 802.3])** + +# Appendix II + +## Networking evolution + +(This appendix does not form an integral part of this Recommendation.) + +## II.1 General + +Networking capabilities are evolving continuously. As network evolution depends on many factors. Evolution affects aspects such as testing requirements, link distances and hardware, PD levels, data rates, equipment components and network configurations. Techniques introduced for one networking type could also be applied to other networking applications. + +## II.2 Testing + +Increased link distances mean that the link screen can carry larger impulse currents due to the difference of local EPR of the connected equipment. Established cable screen current testing circuits can be used for verification, but the test current level may need to be increased. + +If the link uses unscreened or screened cable that is not sufficiently well bonded at both ends, equipment withstand testing may need to be done at higher-than-normal voltage levels. + +Because of interactions between the NPSE, NPD and possibly the link, a system-level test, rather than an equipment test, is often desirable. Test circuits often employ a network coupler-decoupler (NCD) to direct the surge stress into the EUT. However, in certain DC-powered systems, the use of a standard NCD has caused equipment to become non-operational or, in extreme cases, to fail. This problem has led to a change in DC powered test configurations, the rationale for this is covered in [b-ITU-T K-Suppl.15]. + +# Bibliography + +- [b-ITU-T K.12] Recommendation ITU-T K.12 (2024), *Characteristics of gas discharge tubes for the protection of telecommunication installations.* +- [b-ITU-T K.39] Recommendation ITU-T K.39 (2019), *Risk assessment of damages to telecommunication sites due to lightning discharges.* +- [b-ITU-T K.96] Recommendation ITU-T K.96 (2014), *Surge protective components: Overview of surge mitigation functions and technologies.* +- [b-ITU-T K.99] Recommendation ITU-T K.99 (2017), *Surge protective component application guide – Gas discharge tubes.* +- [b-ITU-T K.103] Recommendation ITU-T K.103 (2015), *Surge protective component application guide – Silicon PN junction components.* +- [b-ITU-T K.126] Recommendation ITU-T K.126 (2017), *Surge protective component application guide – High frequency signal isolation transformers.* +- [b-ITU-T K.128] Recommendation ITU-T K.128 (2018), *Surge protective component application guide – metal oxide varistor (MOV) components.* +- [b-ITU-T K.129] Recommendation ITU-T K.129 (2018), *Characteristics and ratings of silicon PN junction voltage clamping components used for the protection of telecommunication installations.* +- [b-ITU-T K.140] Recommendation ITU-T K.140 (2019), *Surge protective component application guide – Fuses.* +- [b-ITU-T K.144] Recommendation ITU-T K.144 (2019), *Surge protective component application guide - Self-restoring thermally activated overcurrent protectors.* +- [b-ITU-T K-Suppl.15] ITU-T K-series Recommendations Supplement 15 (2018), *ITU-T K.20, K.21 and K.44 – Internal DC powering interface surge testing factors.* +- [b-IEC 60099-5] International Standard IEC 60099-5:2018, *Surge arresters – Part 5: Selection and application recommendations.* +- [b-IEEE 802.3] IEEE 802.3-2022, *IEEE Standard for Ethernet.* +- [b-ETSI EN 302 099] European Standard ETSI EN 302 099 V2.2.1 (2021), *Environmental engineering (EE); Powering of equipment in access network.* +- [b-ISO/IEC 11801-1] International Standard ISO/IEC 11801-1:2017, *Information technology – Generic cabling for customer premises – Part 1: General requirements.* +- [b-ISO/IEC TR 15044] Technical Report ISO/IEC TR 15044:2000, *Information technology – Terminology for the Home Electronic System (HES).* +- [b-Gazivoda-Nikolic] Gazivoda-Nikolic, T. (2018). *Gas discharge tube (GDT) operation in Ethernet protection.* Paper presented at: ATIS Protection Engineers Group Conference 2018. Washington, DC: Alliance for Telecommunications Industry Solutions. Available [viewed 2023-09-28] from: + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.148-202012-I_PDF-E/raw.md b/marked/K/T-REC-K.148-202012-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..3067ebcefb8d35deb345f7da255fc7ce7ffbd8be --- /dev/null +++ b/marked/K/T-REC-K.148-202012-I_PDF-E/raw.md @@ -0,0 +1,384 @@ + + +I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n + +# **ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +# **K.148** + +(12/2020) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +# --- **Multiservice surge protective device application guide** + +Recommendation ITU-T K.148 + +**ITU-T** + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with a white grid pattern, and the letters 'ITU' in white, bold, sans-serif font, superimposed on the globe. + +ITU logo + + + +## Recommendation ITU-T K.148 + +# Multiservice surge protective device application guide + +## Summary + +A multiservice surge protective device (MSPD) protects two or more services e.g., mains and telecommunications, and has a common bonding point for the service surge protective devices (SPDs) contained in the MSPD. Recommendation ITU-T K.148 provides application guidance on MSPDs and explains their uses, required performance parameters and usage consequences. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.148 | 2020-12-14 | 5 | 11.1002/1000/14561 | + +## Keywords + +ICT service, multiservice surge protective device, MSPD, power service, surge reference equaliser. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2021 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +**Page** + +- 1 Scope 1 +- 2 References 1 +- 3 Definitions 1 + - 3.1 Terms defined elsewhere 1 + - 3.2 Terms defined in this Recommendation 2 +- 4 Abbreviations and acronyms 2 +- 5 Conventions 3 +- 6 Individual service SPDs 3 + - 6.1 Surge mitigation functions 3 + - 6.2 Power service protection 4 + - 6.3 Signal service protection 5 + - 6.4 Individual SPD earthing problems 5 +- 7 Surge reference equaliser (MSPD concept) 6 +- 8 MSPD implications 8 + - 8.1 Protected-side earth loop currents 8 + - 8.2 SPD cross-coupling 8 + - 8.3 High impedance or missing local earth connection 8 +- 9 Summary 8 +- Bibliography 9 + + + +# Multiservice surge protective device application guide + +## 1 Scope + +This Recommendation provides application guidance on multiservice surge protective devices (MSPDs) and explains how MSPDs provide local overvoltage protection for the services used by an equipment or equipment cluster. The requirements of the individual service surge protective devices (SPDs) are outlined, together with possible interactions on the MSPD protected side. This Recommendation also explains how the MSPD interacts with the surges on the services and the consequences of these surges when the local protective earthing (PE) connection is high impedance or is missing. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +None. + +## 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 common mode conversion** [b-ITU-T K.96]: Process by which a differential mode electrical signal is produced in response to a common mode electrical signal. + +**3.1.2 common-mode surge** [b-ITU-T K.96]: Surge appearing equally on all conductors of a group at a given location. + +NOTE 1 – The reference point for common-mode surge voltage measurement can be a chassis terminal, or a local earth/ground point. + +NOTE 2 – Also known as longitudinal surge or asymmetrical surge. + +**3.1.3 band-pass filter** [b-ITU-T K.96]: Filter that allows passage of a desired range of frequencies and attenuates frequencies outside the desired range. + +NOTE – This definition is based on the definition provided in [b-IEEE Std 802.7]. + +**3.1.4 common-mode choke filter** [b-ITU-T K.96]: Series in-line transformer used to mitigate common-mode current flow without affecting differential current flow. + +**3.1.5 common-mode rejection filter** [b-ITU-T K.96]: Filter type, usually a balanced filter that attenuates the signal common to both input lines; that signal is called the common-mode signal. + +NOTE – This definition is based on the definition provided in [b-IEEE Std 1549]. + +**3.1.6 differential-mode surge** [b-ITU-T K.96]: Surge occurring between any two conductors or two groups of conductors at a given location. + +NOTE 1 – The surge source maybe be floating, without a reference point or connected to reference point, such as a chassis terminal, or a local earth/ground point. + +NOTE 2 – Also known as metallic surge or transverse surge or symmetrical surge or normal surge. + +**3.1.7 filter** [b-IEEE Std 802.7]: Circuit that selects or rejects one or more components of a signal related to frequency. + +**3.1.8 high-pass filter** [b-ITU-T K.96]: Electrical network that passes higher frequencies, attenuates lower frequencies and blocks DC levels. + +NOTE – This definition is based on the definition provided in [b-IEEE Std 1149.6]. + +**3.1.9 low-pass filter** [b-IEEE Std 1149.6]: Electrical network that passes lower frequencies, including DC levels, and attenuates higher frequencies. + +**3.1.10 modes of protection (of a voltage limiting surge protective device (SPD) or equipment port)** [b-ITU-T K.99]: List of terminal-pairs where the diverted surge current is directly between that terminal-pair without flowing via other terminals. + +**3.1.11 multiservice surge protective device** [b-ITU-T K.85]: A surge protective device (SPD) containing both telecommunications and mains protection. It may also include port protection for video or Ethernet. + +**3.1.12 surge protective component (SPC)** [b-ITU-T K.96]: Component specifically included in a device or equipment for the mitigation of the onward propagation of overvoltages or overcurrents or both. + +**3.1.13 surge protective device (SPD)** [b-ITU-T K.96]: Device that mitigates the onward propagation of overvoltages or overcurrents or both. + +**3.1.14 surge reference equalizer** [b-IEC TR 62066]: Device used for connecting equipment to external systems whereby all conductors connected to the protected load are routed, physically and electrically, through a single enclosure with a shared reference point between the input and output ports of each system. + +NOTE – Sharing the reference point may be accomplished within the device either by a direct bond or through a suitable device, such as an SPD which maintains isolation during normal conditions but provides an effective bond during the occurrence of a surge in one or both systems. + +### **3.2 Terms defined in this Recommendation** + +This Recommendation defines the following terms: + +**3.2.1 earth loop:** Potentially detrimental loop formed when two or more points in an electrical system that are connected to their local earth potential are also interconnected by earth referenced conductors, which creates a loop that will carry current if the local earths are not at the same potential. + +## **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|------------------------------------------| +| GDT | Gas Discharge Tube | +| IP | Ingress Protection | +| ICT | Information and Communication Technology | +| MOV | Metal-oxide Varistor | +| MSPD | Multiservice Surge Protective Device | +| PE | Protective Earthing | +| SPC | Surge Protective Component | +| SPD | Surge Protective Device | + +## 5 Conventions + +None. + +## 6 Individual service SPDs + +### 6.1 Surge mitigation functions + +SPDs are normally fitted to cabling when failures have occurred due to overvoltages or there are concerns about the service overvoltage levels. Common-mode surge overvoltages occur on all conductors within the cable. Figure 1 shows several mitigation options for a common-mode surge: + +- voltage limit the surge voltage from an earth reference potential by using non-linear voltage limiting components, +- block the voltage surge with an isolating transformer, +- filter out the surge frequencies if the service and lightning spectrums do not overlap, +- use a common-mode choke, which has a high impedance to common-mode surge and a low impedance to the differential signal, +- use a series electronic current limiter as these are fast enough to operate under surge conditions. + +![Figure 1 – Common-mode surge mitigation options](dbe553cf16dd14073b89a8263a428664_img.jpg) + +The diagram illustrates common-mode surge mitigation options across two parallel lines connecting an 'Equipotential conductor group' on the left to a 'Protected load' on the right. A 'Surge' is indicated entering from the left. The mitigation stages are labeled a) through e): + a) Shunt voltage limiter: Two non-linear components (labeled V) connected from each line to the 'Reference potential and functional bonding' line at the bottom. + b) In-line isolating transformer: A transformer symbol in series with the lines. A dashed line indicates a 'Screened version' connected to the reference potential. + c) Series and shunt filter: A box containing a Z-shaped symbol representing a filter network. + d) Common-mode choke: A dual-winding inductor symbol. + e) Series current limiter: Two circular symbols with vertical lines, one in series with each conductor. + The entire circuit is referenced to a bottom line labeled 'Reference potential and functional bonding'. The figure is identified as K.148(20)\_F01. + +Figure 1 – Common-mode surge mitigation options + +**Figure 1 – Common-mode surge mitigation options** + +The Figure 1 a) shunt voltage limiter could be realised by many technologies such as metal-oxide varistor (MOV), gas discharge tube (GDT), PN junction diode, foldback diode and punch-through diode. The description and operation of these protection technologies is covered in [b-ITU-T K.96]. + +Differential mode surge overvoltages occur between conductors or sets of cable conductors. Figure 2 shows several mitigation options for a differential-mode surge: + +- voltage limit the surge voltage between the conductors by using non-linear voltage limiting components, +- if the signal transformer core saturates, stopping transformer action, surge truncation will occur, see [b-ITU-T K.126], +- filter out the surge frequencies if the service and lightning spectrums do not overlap, +- use a series electronic current limiter as these are fast enough to operate under surge conditions. + +![Figure 2: Differential-mode surge mitigation options. The diagram shows four options (a, b, c, d) for protecting a load from surges. Option a) is a shunt voltage limiter (MOV) connected in parallel with the load. Option b) is an in-line isolating transformer. Option c) is a series and filter (inductor and capacitor) connected in series with the load. Option d) is a series current limiter (diode) connected in series with the load. A surge waveform is shown on the left. A reference potential and functional bonding line is shown at the bottom. The diagram is labeled K.148(20)_F02.](a5ee5c23b6dc52ec1d724b76d5a5f58f_img.jpg) + +Figure 2: Differential-mode surge mitigation options. The diagram shows four options (a, b, c, d) for protecting a load from surges. Option a) is a shunt voltage limiter (MOV) connected in parallel with the load. Option b) is an in-line isolating transformer. Option c) is a series and filter (inductor and capacitor) connected in series with the load. Option d) is a series current limiter (diode) connected in series with the load. A surge waveform is shown on the left. A reference potential and functional bonding line is shown at the bottom. The diagram is labeled K.148(20)\_F02. + +**Figure 2 – Differential-mode surge mitigation options** + +The description and operation of these protection technologies is covered in [b-ITU-T K.96]. + +### 6.2 Power service protection + +The main requirement for power service protection is to limit the common mode surge overvoltage and generally the approach of Figure 1a) is used. Figure 3 shows different ways MOVs can be connected to protect a two-wire power source. Circuit a) has one MOV (MOV1) to directly protect the power source and a second MOV (MOV2) to protect the power source insulation to earth. Circuit b) has one MOV (MOV1) protecting the power feed conductor to earth and a second MOV (MOV2) to protect the power return conductor to earth. Circuit c) has one MOV (MOV1) protecting the power feed conductor to earth, a second MOV (MOV2) protecting the power return conductor to earth and a third MOV (MOV3) directly protecting the power source. Circuit d) has two series connected MOVs (MOV1 and MOV3) directly protecting the power source and one MOV (MOV2), connected to the junction of MOV1 and MOV3, protecting the power source insulation to earth. + +![Figure 3: Circuit examples of powering feed protection. The diagram shows four circuit examples (a, b, c, d) for protecting a two-wire power source. Circuit a) shows MOV1 connected between the power feed and power return, and MOV2 connected between the power return and earth. Circuit b) shows MOV1 connected between the power feed and earth, and MOV2 connected between the power return and earth. Circuit c) shows MOV1 connected between the power feed and earth, MOV2 connected between the power return and earth, and MOV3 connected between the power feed and power return. Circuit d) shows MOV1 and MOV3 connected in series between the power feed and power return, and MOV2 connected between their junction and earth. The diagram is labeled K.148(20)_F03.](b8661c6c54f72ecc7ff6cb05e47b2891_img.jpg) + +Figure 3: Circuit examples of powering feed protection. The diagram shows four circuit examples (a, b, c, d) for protecting a two-wire power source. Circuit a) shows MOV1 connected between the power feed and power return, and MOV2 connected between the power return and earth. Circuit b) shows MOV1 connected between the power feed and earth, and MOV2 connected between the power return and earth. Circuit c) shows MOV1 connected between the power feed and earth, MOV2 connected between the power return and earth, and MOV3 connected between the power feed and power return. Circuit d) shows MOV1 and MOV3 connected in series between the power feed and power return, and MOV2 connected between their junction and earth. The diagram is labeled K.148(20)\_F03. + +**Figure 3 – Circuit examples of powering feed protection** + +Circuits a) and b) are the least cost using only two MOVs. Circuits c) and d) are more expensive using 3 MOVs. For DC supplies, if the voltage polarity of the powering conductors is known, diode steering, D1 and D2, can be added to the Figure 3 c) circuit to ensure that common-mode impulses of any polarity only charge and do not discharge the power source, see Figure 4. For any impulse polarity, the powering source voltage increase during an impulse is limited by MOV3. + +![Circuit diagram of a diode steering variant of circuit c). The diagram shows a 'Power feed +' line and a 'Power return -' line. MOV3 is connected between these two lines. Below the 'Power return -' line, MOV2 is connected between the return line and ground, and MOV1 is connected between the 'Power feed +' line and ground. Diodes D1 and D2 are connected in series between the 'Power return -' line and ground, with D1 pointing towards the 'Power feed +' line and D2 pointing towards ground. The entire assembly is connected to a common ground. The label 'K.148(20)_F04' is at the bottom.](cfef993dcc8fb513de79eb1f93cf26ae_img.jpg) + +Circuit diagram of a diode steering variant of circuit c). The diagram shows a 'Power feed +' line and a 'Power return -' line. MOV3 is connected between these two lines. Below the 'Power return -' line, MOV2 is connected between the return line and ground, and MOV1 is connected between the 'Power feed +' line and ground. Diodes D1 and D2 are connected in series between the 'Power return -' line and ground, with D1 pointing towards the 'Power feed +' line and D2 pointing towards ground. The entire assembly is connected to a common ground. The label 'K.148(20)\_F04' is at the bottom. + +**Figure 4 – Diode steering variant of circuit c)** + +Important power service SPD performance parameters are the maximum continuous operation voltage, limiting voltage and surge resistibility. For all the SPD parameters consult the appropriate international, regional or national standards and manufacturers data sheets. Examples of power SPD standards are [b-IEC 61643-11] and [b-UL 1449]. Generally, power SPD standards do not cover the inclusion of filters simultaneous surge on all the powering lines. Outside use SPDs are likely to have an ingress protection (IP) rating indicating the enclosure sealing effectiveness against intrusion of foreign bodies and moisture. + +[b-IEC 60664-1] lists the following preferred overvoltage categories of 60 V, 330 V, 500 V, 800 V, 1.5 kV, 2.5 kV, 4 kV, 6 kV, 8 kV, 10 kV and 15 kV. + +### 6.3 Signal service protection + +Generally, ports for signal services have less surge resistance than power services, particularly for differential mode surge. Differential mode surges are often created by non-synchronous operation of common mode protection elements. + +Services supplied using co-axial cable only need voltage mitigation between the centre conductor and cable screen. In high frequency signal cases a passive quarter-wave shorting stub protector can be used to filter out the lightning frequency components. + +Services supplied with twisted pair cabling need voltage mitigation between the conductors. Multi-twisted pair cables supplying power may also need inter-pair voltage mitigation between the pairs of differing potentials. + +Important signal service SPD performance parameters are the maximum continuous operation voltage, limiting voltage and surge resistibility both for common mode and differential mode surges. For all the SPD parameters consult the appropriate international, regional or national standards and manufacturers data sheets. Outside use SPDs are likely to have an ingress protection IP rating indicating the enclosure sealing effectiveness against intrusion of foreign bodies and moisture. + +### 6.4 Individual SPD earthing problems + +When SPDs are individually applied to services, as shown in Figure 5, the common mode surge current from the SPD "C" terminal to the local earth reference via the earthing cable can create a potential difference from the true earth potential. Further the local earth references themselves may be at different potentials. For example, a 1 m connecting cable has an inductance of about + +1.5 $\mu\text{H/m}$ . A diverted surge current of 50 A/ $\mu\text{s}$ would create an inductive voltage of 75 V/m. This inductive voltage adds to the SPD limiting voltage. + +![Diagram illustrating individual SPD earthing for power and ICT services. It shows four SPD units (Power SPD, ICT SPD1, ICT SPDn, and Equipment ICT SPD) connected to a central ICT equipment cluster. Each SPD has its 'C' terminal connected to a local earth reference. The Power SPD receives 'Power in' and provides 'Cluster powering' to the cluster. ICT SPD1 receives 'ICT service 1 in' and provides 'ICT service 1 to cluster' to the cluster. ICT SPDn receives 'ICT service n in' via a 'Screened cable' and provides 'ICT service n to cluster' via a 'Screened cable' to the cluster. The Equipment ICT SPD receives 'ICT service from cluster' and provides 'ICT service out'.](007b053fe94a8348f75128a584503fd0_img.jpg) + +The diagram shows the earthing configuration for various Surge Protection Devices (SPDs) connected to an ICT equipment cluster. On the right is a large vertical rectangle labeled 'ICT equipment cluster'. To its left are four smaller boxes representing different SPDs, each with a 'C' terminal connected to a 'Local earth reference' (indicated by a ground symbol and the letter 'C'). + +- Power SPD:** Located at the top. It receives 'Power in' from the left and provides three arrows labeled 'Cluster powering' to the ICT equipment cluster. +- ICT SPD1:** Located below the Power SPD. It receives 'ICT service 1 in' from the left and provides an arrow labeled 'ICT service 1 to cluster' to the ICT equipment cluster. +- ICT SPDn:** Located below ICT SPD1. It receives 'ICT service n in' from the left via a 'Screened cable' and provides an arrow labeled 'ICT service n to cluster' via a 'Screened cable' to the ICT equipment cluster. +- Equipment ICT SPD:** Located at the bottom. It receives an arrow labeled 'ICT service from cluster' from the ICT equipment cluster and provides an arrow labeled 'ICT service out' to the left. + +The diagram is labeled 'K.148(20)\_F05' in the bottom right corner. + +Diagram illustrating individual SPD earthing for power and ICT services. It shows four SPD units (Power SPD, ICT SPD1, ICT SPDn, and Equipment ICT SPD) connected to a central ICT equipment cluster. Each SPD has its 'C' terminal connected to a local earth reference. The Power SPD receives 'Power in' and provides 'Cluster powering' to the cluster. ICT SPD1 receives 'ICT service 1 in' and provides 'ICT service 1 to cluster' to the cluster. ICT SPDn receives 'ICT service n in' via a 'Screened cable' and provides 'ICT service n to cluster' via a 'Screened cable' to the cluster. The Equipment ICT SPD receives 'ICT service from cluster' and provides 'ICT service out'. + +**Figure 5 – Individual SPD earthing** + +The power SPD will be connected to the mains plug/socket local earth reference. The incoming service SPD1 and outgoing service equipment SPD will be connected to whatever local earth reference is provided. For the screened cable SPDn the earth reference could be applied to the cable originating end. + +## 7 Surge reference equaliser (MSPD concept) + +A surge reference equaliser does two things; it brings together all the service SPDs by locating them in a single enclosure and provides a local earth reference for all the SPD "C" terminals to directly connect to. Figure 6 shows the configuration. + +![Diagram of SPDs in a surge reference equaliser configuration. A dashed box labeled 'SPD enclosure' contains a 'Power SPD', 'ICT SPD1', 'Common bonding point', 'ICT SPDn', and 'Equipment ICT SPD'. 'Power in' enters the Power SPD, which is connected to a 'Local earth reference' via a 'C' (capacitor/grounding) symbol. The Power SPD outputs three 'Cluster powering' lines to an 'ICT equipment cluster'. 'ICT service 1 in' enters the ICT SPD1, which outputs 'ICT service 1 to cluster' to the cluster. 'ICT service n in' enters the ICT SPDn, which is connected to a 'Local earth reference' via a 'C' symbol and a 'Screened cable'. The ICT SPDn outputs 'ICT service n to cluster' to the cluster. The 'Equipment ICT SPD' outputs 'ICT service out' and receives 'ICT service from cluster' from the cluster. All SPDs are connected to the 'Common bonding point' via green lines. The label 'K.148(20)_F06' is at the bottom right.](af7916c89a458fdab6c3f443217388ae_img.jpg) + +Diagram of SPDs in a surge reference equaliser configuration. A dashed box labeled 'SPD enclosure' contains a 'Power SPD', 'ICT SPD1', 'Common bonding point', 'ICT SPDn', and 'Equipment ICT SPD'. 'Power in' enters the Power SPD, which is connected to a 'Local earth reference' via a 'C' (capacitor/grounding) symbol. The Power SPD outputs three 'Cluster powering' lines to an 'ICT equipment cluster'. 'ICT service 1 in' enters the ICT SPD1, which outputs 'ICT service 1 to cluster' to the cluster. 'ICT service n in' enters the ICT SPDn, which is connected to a 'Local earth reference' via a 'C' symbol and a 'Screened cable'. The ICT SPDn outputs 'ICT service n to cluster' to the cluster. The 'Equipment ICT SPD' outputs 'ICT service out' and receives 'ICT service from cluster' from the cluster. All SPDs are connected to the 'Common bonding point' via green lines. The label 'K.148(20)\_F06' is at the bottom right. + +**Figure 6 – SPDs in a surge reference equaliser configuration** + +In Figure 6, the common bonding point, or "star" connection has two external earth reference points; one from the power SPD mains plug/socket local earth reference and the other from the screened cable remote earth reference. This means that the diverted surge current can split between the power and screened cable earth references. + +To avoid earth loops in normal operation, one SPDn option is to make the screened cable "C" connection to the common bonding point via an SPD with a switching function, which maintains isolation during normal conditions but provides a bond during the occurrence of a surge. + +The surge reference equaliser is now called an MSPD, although there may not be any SPDs in it, only SPCs giving the equivalent surge functionality of the replaced SPDs. Figure 7 shows a typical MSPD for protecting power, antenna, telephone and Ethernet services with warning lights for protection failure and missing earth connection. + +In terms of surge parameters for a particular service, [b-ITU-T K.44] and [b-ITU-T K.21] provide guidance on test circuits and values. Assuming the cluster equipment ports meet [b-ITU-T K.21] requirements, the MSPD should be regarded as [b-ITU-T K.21] primary protection that is coordinated with the equipment cluster port protection. + +![A black Multi-Service Protection Device (MSPD) unit. It has a power cord on the left and a red power switch. The front panel features several ports: four AC power outlets, two USB ports, two Ethernet (RJ45) ports, and two coaxial (F-type) ports. There are also two small indicator lights, one green and one red, and a label 'Power Surge Protection' above the Ethernet and coaxial ports.](0dd5ee731e9d7e34e498b5c926110773_img.jpg) + +A black Multi-Service Protection Device (MSPD) unit. It has a power cord on the left and a red power switch. The front panel features several ports: four AC power outlets, two USB ports, two Ethernet (RJ45) ports, and two coaxial (F-type) ports. There are also two small indicator lights, one green and one red, and a label 'Power Surge Protection' above the Ethernet and coaxial ports. + +**Figure 7 – MSPD for protecting power, antenna, phone and Ethernet services** + +## **8 MSPD implications** + +### **8.1 Protected-side earth loop currents** + +If there is a cluster of equipment, they are likely to be connected to the power service and possibly interconnected. This means there will be the possibility of earth loop currents if the MSPD earth referenced leads are ineffectively directly connected to the common bonding point. [b-IEEE C62.50] describes a surge test procedure that measures surge currents that flow in the protected side ground loops. Generally, such a test is not necessary provided all the earthed referenced conductors are correctly returned to the common bonding point. + +### **8.2 SPD cross-coupling** + +Localized electric, magnetic and electromagnetic fields within the MSPD can be caused by the operation of a power SPD. These fields can couple into the SPDs and wiring on other services causing signal disruption. [b-IEEE C62.50] has a test procedure that measures the coupled levels of surge open-circuit voltage and surge short-circuit current on to unsurged services. The loads that are normally connected to communications service ports are simulated by resistive terminations connected to both the service port protected and unprotected sides. + +### **8.3 High impedance or missing local earth connection** + +When SPD operation diverts surge current into the common bonding point, the voltage developed on the earthing system can appear as an earth potential rise on other service SPDs. If the potential rise is sufficiently large it can cause these other services SPDs into conduction, which will divert portions of the surge current on to these other services. If an earthing reference is not provided the surge will propagate to all services, see [b-ITU-T K.134]. Generally, the use of MSPD technology will not cause any additional hazards compared to individual SPDs applied to services. + +## **9 Summary** + +Use of an MSPD creates a zone of protection for the equipment cluster on the protected side of the MSPD. Individual SPDs located at various positions cannot do this. The MSPD protection types and their performance depends on the type of services required by the equipment cluster protection and the expected transient voltage environment. + +It should be remembered that equipment connected to the MSPD unprotected side may suffer surges diverted from other MSPD services and appropriate steps should be taken to protect such equipment from these diverted surges. + +## Bibliography + +- [b-ITU-T K.21] Recommendation ITU-T K.21 (2019), *Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents.* +- [b-ITU-T K.44] Recommendation ITU-T K.44 (2019), *Resistibility tests for telecommunication equipment exposed to overvoltages and overcurrents – Basic Recommendation.* +- [b-ITU-T K.85] Recommendation ITU-T K.85 (2011), *Requirements for the mitigation of lightning effects on home networks installed in customer premises.* +- [b-ITU-T K.96] Recommendation ITU-T K.96 (2014), *Surge protective components: Overview of surge mitigation functions and technologies.* +- [b-ITU-T K.98] Recommendation ITU-T K.98 (2014), *Overvoltage protection guide for telecommunication equipment installed in customer premises.* +- [b-ITU-T K.99] Recommendation ITU-T K.99 (2017), *Surge protective component application guide – Gas discharge tubes.* +- [b-ITU-T K.126] Recommendation ITU-T K.126 (2017), *Surge protective component application guide – High frequency signal isolation transformers.* +- [b-ITU-T K.134] Recommendation ITU-T K.134 (2018), *Protection of small-size telecommunication installations with poor earthing conditions.* +- [b-ITU-T K.143] Recommendation ITU-T K.143 (2019), *Guidance on safety relating to the use of surge protective devices and surge protective components in telecommunication terminal equipment.* +- [b-IEC 60664-1] IEC 60664-1:2020, *Insulation coordination for equipment within low-voltage supply systems – Part 1: Principles, requirements and tests.* +- [b-IEC 61643-11] IEC 61643-11:2011, *Low-voltage surge protective devices – Part 11: Surge protective devices connected to low-voltage power systems – Requirements and test methods.* +- [b-IEC TR 62066] IEC TR 62066:2002, *Surge overvoltages and surge protection in low-voltage a.c. power systems – General basic information.* +- [b-IEEE C62.50] IEEE C62.50 – 2012, *IEEE Standard for Performance Criteria and Test Methods for Plug-in (Portable) Multiservice (Multiport) Surge-Protective Devices for Equipment Connected to a 120 V/240 V Single Phase Power Service and Metallic Conductive Communication Line(s).* +- [b-IEEE Std 802.7] IEEE 802.7-1989, *Local Area Networks: IEEE Recommended Practice: Broadband Local Area Networks (withdrawn).* +- [b-IEEE Std 1149.6] 1149.6-2015, *IEEE Standard for Boundary-Scan Testing of Advanced Digital Networks.* +- [b-IEEE Std 1549] 1549-2011, *IEEE Standard for Microwave Filter Definitions.* +- [b-UL 1449] UL Standard (2021), *Surge Protective Devices.* + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.149-202012-I_PDF-E/raw.md b/marked/K/T-REC-K.149-202012-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..bdf4a8862c6d4a6c0196eb46921255e8a6292361 --- /dev/null +++ b/marked/K/T-REC-K.149-202012-I_PDF-E/raw.md @@ -0,0 +1,485 @@ + + +International Telecommunication Union + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.149** + +(12/2020) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Passive intermodulation test methods of array +antenna systems in mobile communication +systems** + +Recommendation ITU-T K.149 + +ITU-T + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with a white grid pattern, overlaid by the letters 'ITU' in a bold, sans-serif font. The globe is tilted on its axis. + +ITU logo + + + +# Recommendation ITU-T K.149 + +# Passive intermodulation test methods of array antenna systems in mobile communication systems + +## Summary + +Recommendation ITU-T K.149 specifies methods for measuring the passive intermodulation level of array antenna systems in mobile communication systems, including test equipment and test procedures. + +This Recommendation covers the following frequency ranges, but is not limited to the following ranges: LTE 700, APT 700, LTE 800, Cellular 850, E-GSM 900, DCS 1800, PCS 1900, AWS 1700/2100, UMTS 2100 and LTE 2600 operating bands. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.149 | 2020-12-14 | 5 | 11.1002/1000/14562 | + +## Keywords + +Array antenna, measurement, mobile communication, passive intermodulation. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2021 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|--------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 1 | +| 4 Abbreviations and acronyms ..... | 1 | +| 5 Conventions ..... | 2 | +| 6 Measuring method of passive intermodulation..... | 2 | +| 6.1 Requirements of test conditions ..... | 2 | +| 6.2 Measurement accuracy ..... | 2 | +| 6.3 Safety..... | 2 | +| 6.4 Test environment ..... | 3 | +| 6.5 Test setup and procedure ..... | 4 | +| 6.6 The measurement uncertainty..... | 6 | +| Annex A – Antenna design and erection ..... | 8 | +| A.1 The impact of the environment on PIM ..... | 8 | +| A.2 Antenna port connection..... | 8 | +| A.3 Antenna erection method to avoid passive intermodulation ..... | 8 | +| A.4 Adjacent passive intermodulation source..... | 8 | +| Annex B – Design and evaluation of the PIM test chamber ..... | 9 | +| B.1 Introduction ..... | 9 | +| B.2 RF absorbing material ..... | 9 | +| B.3 Support structure and walls ..... | 10 | +| B.4 RF shielding..... | 10 | +| B.5 RF chamber evaluation..... | 10 | +| Bibliography..... | 12 | + +# Introduction + +With the development of mobile communications, the data carried in the fixed bandwidth has increased rapidly. There are many signals of different frequencies in the same transmission medium. Since the transmission medium has certain nonlinear characteristics, when two or more signals with multiple different frequencies are mixed into the passive components, intermodulation products of different amplitudes are produced at other frequencies. This is called passive intermodulation (PIM). + +Passive components include antennas, radio frequency (RF) feeders, connectors, filters, duplexers, directional couplers, RF termination loads, and attenuators, etc. When the passive intermodulation falls within the receiving band of a base station, the sensitivity of the receiver is reduced, resulting in a decrease in the quality of the call or the carrier-to-interference ratio (C/I) of the system. + +With the gradual large-scale commercialization of 4G LTE and 5G networks, the number of communication systems and the number of users have greatly increased. Therefore, the design of communication systems requires the use of limited spectrum resources to be as efficient as possible, and passive intermodulation distortion becomes an important factor limiting the system capacity. Massive multi-input multi-output (MIMO) antennas are key technologies in the 5G era, and more post-stage passive components will be introduced, thus bringing more challenges to R&D and testing. In order to reduce this interference, it is very important to perform strict PIM testing on passive components during their production. + +This Recommendation provides a reference for the passive intermodulation (PIM) level measurement of array antennas in mobile communication systems. + +## Recommendation ITU-T K.149 + +# Passive intermodulation test methods of array antenna systems in mobile communication systems + +# 1 Scope + +This Recommendation is applicable to the passive intermodulation (PIM) measurement of passive array antenna systems in mobile communication systems. This Recommendation defines the setup and test methods for antennas in low intermodulation applications that can be found in cellular mobile communications, satellite communications and other multifrequency communications. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[IEC 62037-6] IEC 62037-6:2013, *Passive RF and Microwave Devices, Intermodulation Level Measurement – Part 6: Measurement of Passive Intermodulation in Antennas*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 antenna** [b-ITU-R M.1797]: Any structure or device used to collect or radiate electromagnetic power. + +**3.1.2 mimo** [b-ITU-R M.1797]: A technique that utilizes multiple antennas on both ends of the transmit-receive channel, e.g., at both the base station and the terminal(s) in a wireless network, to provide significant improvements in the capacity or reliability of the system. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following term: + +**3.2.1 fully anechoic chamber**: Shielded enclosure in which all surfaces are covered with material that absorbs electromagnetic energy (i.e., RF absorber) in the frequency range of interest. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|----------------------------------------| +| AUT | Antenna Under Test | +| CDMA | Code Division Multiple Access | +| GSM | Global System for Mobile communication | +| MIMO | Multi-Input Multi-Output | +| PIM | Passive Intermodulation | + +| | | +|-----|------------------| +| RF | Radio Frequency | +| RSS | Root-Sum-Squares | + +# 5 Conventions + +None. + +# 6 Measuring method of passive intermodulation + +## 6.1 Requirements of test conditions + +In order to improve the test accuracy and to ensure test safety, the following conditions are required. These requirements help minimize errors within the test system. + +## 6.2 Measurement accuracy + +The accuracy of PIM tests may be affected by many factors external or internal in the test system. Factors affecting the results of PIM tests of antenna include, but are not limited to, the following: + +- a. Conductive material exposed to the electromagnetic fields radiated by the antenna under test (AUT); +- b. Loose, damaged or corroded AUT mounting accessories; +- c. Loose or corroded accessories exposed to the AUT radiation field; +- d. Radio frequency signal from external sources; +- e. Defective or poorly performing coaxial cables; +- f. Dirty, contaminated and abrasion at the interface connections; +- g. Improper interface connections; +- h. Poorly shielded RF interface connections; +- i. Unfiltered active intermodulation signal from the test equipment; +- j. Transmission line loss should be considered; +- k. Contaminated absorbing material; +- l. Ineffective shielding enclosure; +- m. Improper placed position of AUT in chamber; +- n. Mismatch of test set; + +Since the power level of the PIM is generally very low, the components of the PIM test equipment should have high performance and low PIM characteristics. The residual intermodulation level generated by the synthesizer, directional coupler, filter, etc., shall be controlled below 10 dB of PIM level of the array antenna. For example, it is assumed that the intermodulation of the measured antenna is $-150$ dBc, and the residual intermodulation of the measuring equipment is at least $-160$ dBc. The matching load used in the test shall adopt cable load to ensure the normal operation of the test equipment. + +## 6.3 Safety + +High voltages and high radiant energy may be present within the AUT and test environment, so the AUT should be properly placed to ensure that testing personnel are not exposed to radiation that exceeds the limits defined in national regulations for workers. + +## 6.4 Test environment + +**In-situ test :** Passive intermodulation tests can be done in in-situ conditions if permitted by the electromagnetic noise and radio environment. The RF radiation level should meet the national regulations when performing such tests. In addition, the RF energy radiated by the AUT may generate passive intermodulation on surrounding objects and reflect it back into the antenna, resulting in test errors in the passive intermodulation results of the antenna. In addition, external RF signals may also affect the intermodulation test results. A survey of the frequencies locally in use is recommended before testing. PIM signals may be affected by external interference in open space. It is recommended that PIM signals measured in a microwave anechoic chamber can be used as a reference. + +**Test in anechoic chamber:** The absorbers and shielding enclosure of chambers may also produce PIM. These PIM products can be amplified by the antenna gain, and can interfere with the test results, causing measurement uncertainties. Standard anechoic test chambers may provide reasonable shielding and RF attenuation, but they may not be suitable for low PIM antenna measurements. Their residual PIM may be much too high. Besides the very high shielding, an ideal chamber provides lowest residual passive intermodulation. To achieve best results, special chamber shielding material with properly designed pyramidal electromagnetic absorbing material and special manufacturing techniques needs to be considered comprehensively. Related to this, the maximum measurable gain and power of PIM test chambers should be evaluated before the test. See Annex B for information on the construction and evaluation of the passive intermodulation test chamber. + +**Test signal configuration:** In the process of upgrading communication networks from 2G to 5G, the signal bandwidth of wireless communication increases from 200 kHz for GSM to 100 MHz and 400 MHz for 5G. Both continuous wave signals and modulated wave signals can be used in the test signal configuration. The use of modulation signals for intermodulation testing can truly reflect the situation and possible problems of the tested equipment when used in the actual network. + +Continuous wave signal is first considered (match test), and then, modulated wave signal is implemented if necessary (research, limitation test and compatibility test). + +### **a. Continuous wave signal** + +Continuous wave signals of frequencies $f_1$ and $f_2$ , with equal specified test port power levels, are combined and fed to the antenna array. The PIM is measured over a specified frequency range. The intermodulation products of order $(2f_1 \pm f_2)$ or $(2f_2 \pm f_1)$ , etc., are measured. + +In most cases, the third order intermodulation signals represent the worst condition of unwanted signals generated; Hence, the antenna array is sufficiently characterized by the measurement of these signals. However, the test settings given in clause 6.5 are also suitable for measuring other intermodulation products. + +### **b. Modulated wave signal** + +Modulated wave signals of frequencies $f_1$ and $f_2$ , with equal specified test port power levels, are combined and fed to the antenna array. According to the measured frequency band, the corresponding communication standard modulation signals are generated. The intermodulation product of two wideband modulation signals is a wideband signal, and the spectral bandwidth is calculated as follows: + +$$B_{IM}(m) = |m_1| \times B_1 + |m_2| \times B_2 + \dots + |m_n| \times B_n;$$ + +Where + +$m = |m_1| + |m_2| + \dots + |m_n|$ ; $m_1, m_2, \dots, m_n$ are integer in the formula + +$|m_n|$ is the absolute value of $m_n$ + +$B_1, B_2, \dots, B_n$ is the bandwidth corresponding to input signals $f_1, f_2, \dots, f_n$ . + +The schematic diagram of intermodulation products of two broadband modulation signals with the same bandwidth is shown in Figure 1. + +![Figure 1: Schematic diagram of intermodulation products of two broadband modulation signals with the same bandwidth. The graph shows Power on the y-axis and Frequency on the x-axis. Two main signals, f1 and f2, are shown as tall bars. Between and around them are several smaller bars representing intermodulation products. From left to right, the bars are labeled with their frequency formulas and relative bandwidths: 4f1-3f2 (7B), 3f1-2f2 (5B), 2f1-f2 (3B), f1 (B), f2 (B), 2f2-f1 (3B), 3f2-2f1 (5B), and 4f2-3f1 (7B). The label 'K.149(20)_F01' is at the bottom right.](4e0ade2f41b66d5602160da5cc978274_img.jpg) + +Figure 1: Schematic diagram of intermodulation products of two broadband modulation signals with the same bandwidth. The graph shows Power on the y-axis and Frequency on the x-axis. Two main signals, f1 and f2, are shown as tall bars. Between and around them are several smaller bars representing intermodulation products. From left to right, the bars are labeled with their frequency formulas and relative bandwidths: 4f1-3f2 (7B), 3f1-2f2 (5B), 2f1-f2 (3B), f1 (B), f2 (B), 2f2-f1 (3B), 3f2-2f1 (5B), and 4f2-3f1 (7B). The label 'K.149(20)\_F01' is at the bottom right. + +**Figure 1– Intermodulation products of two broadband modulation signals with the same bandwidth** + +The modulation signal is adopted to take the corresponding standard channel bandwidth as the minimum step for scanning. For example, GSM signal takes 200 kHz as the step and code division multiple access (CDMA) signal takes 1.23 MHz as the step scan, which can cover the whole working frequency band. + +When testing intermodulation, the bandwidth of intermodulation products shall be calculated according to the above formula, and the energy value within the corresponding bandwidth shall be measured on the receiver as the intermodulation level. + +## 6.5 Test setup and procedure + +### 6.5.1 Testing the connection of coaxial cable + +Passive intermodulation testing using coaxial cable requires repeated connection and disconnection of the coaxial connector. The following points should be noted during the test: + +- a. The sealing O-rings of the connector interface should be removed. The O-rings will collect the debris generated during the tightening process of the joint and become another source of passive intermodulation. +- b. Before connecting, check the connectors, dielectric, interface surfaces or flanges for contamination, especially metal fragments. In addition, check the connector's interface surface for burrs, scratches, dents, or damage to the electroplated layer. Properly install and rotate the accessories to minimize the passive intermodulation generated inside the AUT. +- c. After each disconnection, it is recommended to use compressed air to clean the connector interface to remove metal debris. +- d. Ensure that the cable is not stressed or damaged. Damage to the outer and inner conductors in the cable jacket is not recognized by the visual inspection, but intermittent intermodulation signals are generated. One way to detect this is to bend or tap the cable when measuring the intermodulation of the equipment itself. If the PIM signal is fluctuating, the cable may be damaged and should be replaced. +- e. For threaded connectors, it is recommended to use a standard torque wrench to tighten the cable connectors to ensure reliable connection. + +### 6.5.2 Low intermodulation load + +A good low intermodulation load can be made up of a high quality coaxial cable with a long (single attenuation value greater than 10 dB) low intermodulation connector. This connector should be soldered to the inner and outer conductors of the coaxial cable. The entire cable should be secured by a fixture so that there are no metal fatigue cracks due to bending. The PIM level of a typical low intermodulation load can be better than $-163\text{ dBc}$ ( $@2\times 43\text{ dBm}$ ). + +### 6.5.3 Standard connector components + +It is recommended to use the standard component with a fixed value of $-153\text{ dBc}$ ( $@2\times 43\text{ dBm}$ ) and low intermodulation load for cascading tests to calibrate the PIM test instrument. The test result should be within the range of $-153\text{ dBc} \pm 3\text{ dB}$ . + +### 6.5.4 PIM test configuration and test procedure + +The antenna reflected intermodulation test configuration is shown in Figure 2. The antenna transmitted intermodulation test configuration is shown in Figure 3. Different test configurations can be selected according to different scenarios. The antenna can be tested in an open field environment or in an anechoic chamber. The anechoic chamber design should meet the technical requirements of Annex A. For the antenna transmission intermodulation test, a low intermodulation antenna is required at the receiving end, which requires two low intermodulation antennas for evaluation of the test system and test site. + +![Block diagram of the antenna reflected PIM test configuration. Two signal generators, labeled f1 and f2, are connected to amplifiers. Each amplifier is followed by a transmit filter. The outputs of the transmit filters are combined in a combiner (labeled Σ). The output of the combiner is connected to a diplexer. The diplexer has two ports: one connected to the AUT (Antenna Under Test) inside a test chamber, and the other connected to a receive filter. The receive filter is connected to a low noise amplifier, which is then connected to a receiver. The receiver displays a spectrum with four distinct peaks. A label 'K.149(20)_F02' is present in the bottom right corner of the diagram area.](5e92d9e8e9ce204e405bff2367f88176_img.jpg) + +The diagram illustrates the antenna reflected PIM test configuration. It consists of two signal generators, $f_1$ and $f_2$ , each connected to an amplifier and a transmit filter. The outputs of these filters are combined in a combiner (labeled $\Sigma$ ). The combined signal is then sent to a diplexer. One output of the diplexer is connected to the AUT (Antenna Under Test) inside a test chamber. The other output of the diplexer is connected to a receive filter, which is followed by a low noise amplifier and a receiver. The receiver displays a spectrum with four distinct peaks. A label 'K.149(20)\_F02' is present in the bottom right corner of the diagram area. + +Block diagram of the antenna reflected PIM test configuration. Two signal generators, labeled f1 and f2, are connected to amplifiers. Each amplifier is followed by a transmit filter. The outputs of the transmit filters are combined in a combiner (labeled Σ). The output of the combiner is connected to a diplexer. The diplexer has two ports: one connected to the AUT (Antenna Under Test) inside a test chamber, and the other connected to a receive filter. The receive filter is connected to a low noise amplifier, which is then connected to a receiver. The receiver displays a spectrum with four distinct peaks. A label 'K.149(20)\_F02' is present in the bottom right corner of the diagram area. + +**Figure 2 – Antenna reflected PIM test configuration** + +![Figure 3 – Antenna transmitted PIM test configuration. The diagram shows two signal paths, f1 and f2, each consisting of a Generator, an Amplifier, and a Transmit filter. These paths are combined in a Combiner (Σ). The output of the combiner is connected to a Transmit filter, which is then connected to a Test chamber. Inside the test chamber, the signal is transmitted by an AUT (Antenna Under Test) and received by a Receive antenna. The received signal is then connected to a Diplexer. One output of the diplexer is connected to a Load, and the other is connected to a Receive filter. The output of the receive filter is connected to a Low noise amplifier, which is then connected to a Receiver. The label K.149(20)_F03 is present at the bottom right.](d4af765160d04ecef538e5066006dc77_img.jpg) + +Figure 3 – Antenna transmitted PIM test configuration. The diagram shows two signal paths, f1 and f2, each consisting of a Generator, an Amplifier, and a Transmit filter. These paths are combined in a Combiner (Σ). The output of the combiner is connected to a Transmit filter, which is then connected to a Test chamber. Inside the test chamber, the signal is transmitted by an AUT (Antenna Under Test) and received by a Receive antenna. The received signal is then connected to a Diplexer. One output of the diplexer is connected to a Load, and the other is connected to a Receive filter. The output of the receive filter is connected to a Low noise amplifier, which is then connected to a Receiver. The label K.149(20)\_F03 is present at the bottom right. + +**Figure 3 – Antenna transmitted PIM test configuration** + +The diplexer in Figure 2 and the filter in Figure 3 are close to the input port of the AUT, and should have low intermodulation characteristics in order to minimize the intermodulation of the test system itself. The length of the transmission cable and the waveguide should be minimized to reduce the insertion loss and thus transmit more power. Also, coaxial-waveguide adapters should be avoided as much as possible. + +In order to avoid the generation of active intermodulation, each test system has two separate composite signal sources that are separately amplified. The two-carrier intermodulation test equipment generates discrete intermodulation products when passing through the AUT, and the levels of these intermodulation products are measured. To maximize the sensitivity of the test system, one or two low noise amplifiers are usually added before intermodulation signals entering the receiver or spectrum analyser. + +The AUT should keep a certain distance from the door of the chamber. It is recommended to be more than 1 meter. + +The test procedures are as follows: + +**6.5.4.1** The passive intermodulation analyser corresponding to the antenna working frequency band should be used. It is recommended to use the "sweep frequency" test. + +**6.5.4.2** Connecting the signal generator and the power meter with test cable, turn on the instrument transmit power, adjust the output power, to make the power of the test cable output meet the specified requirements. + +**6.5.4.3** During the test, the test cable shall remain stable in the required moving or bending state. It can be verified by connecting a low intermodulation load at one end of the cable. + +**6.5.4.4** Turn off the instrument's transmit power, place the geometric centre of the antenna under test at the centre of the field, and connect the measured antenna port to the measurement system and ensure reliable contact. + +**6.5.4.5** Turn on the instrument's transmit power and the intermodulation level is shown on the interface of the passive intermodulation analyser. + +## **6.6 The measurement uncertainty** + +The uncertainty of the result of a measurement generally consists of several components that can be grouped into two types according to the method used to estimate their numerical values. + +Type A: those evaluated by statistical methods, + +Type B: those evaluated by other means. + +The synthesis uncertainty of the passive intermodulation test system is defined as: + +$$\text{RSS}=U_c = \sqrt{U_1^2 + U_2^2 + \dots U_8^2} \quad (1)$$ + +Where $U_i, i = 1, \dots, 8$ refers to each component of the system. + +Type A: + +Here, $U_1$ indicates the uncertainty caused by repeatability of the human test, which is implemented during a continuous time frame. Specifically, each test is independent, and intermodulation system is reset to initial state when each test finished. The mathematic average of all the human tests is calculated as follow: + +$$\bar{V} = \frac{1}{N} \sum_{i=1}^N V_i \quad (2)$$ + +Where $V_i$ refers to the volt value of each test, and $N$ indicates the number of tests. Therefore, the variance is produced as: + +$$S^2(V_i) = \frac{1}{N} \sum_{i=1}^N (V_i - \bar{V})^2 \quad (3)$$ + +Finally, $U_1$ can be calculated as: + +$$S^2(V_i) = \sqrt{\frac{S^2(V_i)}{N-1}} \quad (4)$$ + +Type B: + +For the uncertainty caused by the system links, it can be calculated as: + +$$U_i = \frac{e_i^{max}}{\varepsilon_i} \quad (5)$$ + +Where $e_i^{max}$ is the maximum error of component $i$ ( $i = 2, \dots, 8$ ), and $\varepsilon_i$ is its distribution factor based on the pattern of probability distribution, which is illustrated in Table 1. + +**Table 1 – The type of system components** + +| Uncertainty component | Error source | Type | Probability distribution | +|-----------------------|------------------------------------------|------|--------------------------| +| $U_1$ | Repeatability of human test | A | Defined by Eq. (4) | +| $U_2$ | Effect of system intermodulation | B | uniform | +| $U_3$ | Receive link error | B | uniform | +| $U_4$ | Power transition link error correcting | B | uniform | +| $U_5$ | Power synthesis link error correcting | B | uniform | +| $U_6$ | Port mismatch error | B | uniform | +| $U_7$ | Receive link difference error correcting | B | uniform | +| $U_8$ | Environment error | B | uniform | + +# Annex A + +## Antenna design and erection + +(This annex forms an integral part of this Recommendation.) + +## A.1 The impact of the environment on PIM + +Any object near the antenna will affect the PIM test result. Ferromagnetic materials, other objects adjacent to the antenna (such as other antennas, supports, metal reflectors, DC and antistatic grounding hardware, loose mechanical connections), different metal junctions, etc., may have an adverse effect on the intermodulation performance of the communication system. + +## A.2 Antenna port connection + +Any antenna port that passes RF signals is a potential passive intermodulation source and should be considered for low intermodulation design. Care should be taken to ensure that the surfaces of all interfaces are clean. Whether it is a coaxial or waveguide joint, check for dirt, metal debris, burrs and other potential contamination. Any coaxial connection should be made in accordance with the manufacturer's specified torque requirements to ensure proper metal contact pressure. If a waveguide is used, the flanges should be connected in accordance with the manufacturer's recommended torque specifications. Be sure to keep the flange edges of the coaxial connector or waveguide aligned. The dielectric and conductors in the connector, including the electroplated layer, are important for the performance of passive intermodulation. Soft electroplated materials (such as gold, silver, etc.) are usually plated with a sufficient thickness (several skin depth) on a hard matrix material (brass, beryllium copper, etc.). The number of coaxial connectors and adapters at the antenna port should be minimized. This will reduce the number of metal contacts and therefore will also reduce the possibility of passive intermodulation generation. + +## A.3 Antenna erection method to avoid passive intermodulation + +The antenna should be safely and reliably installed on the test platform. Ensure that all bolts and clamps that secure the antenna to the supporting structure are fastened and tightened according to the manufacturer's requirements. The coaxial or waveguide transmission line of the antenna input port should also be connected securely and reliably, and friction or movement is prohibited. + +The test platform should facilitate the placement of antennas. The main radiation lobe of the antenna should point to the main test plane of the anechoic chamber. The specifications of the absorbing materials should meet the technical requirements in clause B.2. To reduce the PIM interference of the test platform, it is recommended that the test platform be made of non-metal and low-PIM materials, such as wood structure and glass fibre reinforced plastics. + +When taking the open field test, the impact of external interference should be minimized to meet the test requirements. + +The antenna should be placed away from potential passive intermodulation sources. Potential passive intermodulation sources are: other antennas, buildings, walls, metal reflectors, etc. + +## A.4 Adjacent passive intermodulation source + +It is important to know about the RF environment in which the antenna is mounted. Special attention should be paid to the location of the antenna and it should be kept away from all possible passive intermodulation sources. For example, the metal parts of the antenna should be prevented from being intimately contacted or corroded. In addition, it should be noted that other antenna transmit signals or their harmonics may fall in the AUT receiving band. + +# Annex B + +## Design and evaluation of the PIM test chamber + +(This annex forms an integral part of this Recommendation.) + +## B.1 Introduction + +This section provides guidance for constructing and evaluating an antenna intermodulation test anechoic chamber. Passive intermodulation tests of antennas are more difficult than other non-radiative components. During the intermodulation test, the antenna and the signal source transmit RF energy continuously, which may stimulate potential intermodulation sources in the test environment. In addition, when the outdoor open field test is conducted, it may contain other radio frequency signals, which may cause this test to be impossible. For an accurate and precise antenna PIM measurement system, an anechoic chamber which can shield RF signals and absorb internal reflections of radiated energy is necessary. However, the absorbers and shielding enclosure of chambers may also produce PIM. The noise of the PIM test chamber usually determines the accuracy of the PIM measurement. + +The main components of the RF anechoic chamber are: + +- a. RF absorbing material. +- b. Support structure and wall. +- c. RF shielding. + +## B.2 RF absorbing material + +Radio frequency absorbing materials are typically fabricated from carbon impregnated foam. These materials act as attenuating effects as the radio frequency signal passes. Signal attenuation (energy absorption) is essentially equivalent to a "load" of the antenna. + +There are many types and sizes of RF absorbing materials. The choice of type and size depends on the frequency of operation and the placement within the laboratory. The most critical factor in building a passive intermodulation test laboratory is the proper selection of RF absorbing materials. + +Absorbing material selection principle: + +- a. Select absorbing materials with RF absorption attenuation greater than 30 dB. The frequency range is consistent with the summary. +- b. In order to obtain good results, a sharp-shaped absorbing material is placed in the radiation range of the antenna, and the absorbing material is preferably used in the direction perpendicular to the incident direction of the radiation field. However, the best results can be achieved if the interior of the laboratory is completely covered by RF absorbing material. +- c. The area of the absorbing material to be laid should be large enough to avoid reflections. In addition, for safety reasons, the absorbing material should be flame retardant and have sufficient power tolerance. +- d. When attaching the absorbing material to the shielding body in the anechoic chamber, it should be ensured that the installation position of the absorbing material is continuous to avoid gaps. Otherwise, signals may leak to the metal shielding layer through the gaps, causing PIM interference signals and affecting the PIM test precision. +- e. It is recommended that special parts in the anechoic chamber, such as the ventilation waveguide port, shielding door, test platform, lighting burner, smoke sensor, and monitor, be paved with RF absorbing materials. + +- f. The lighting burner is recommended to be placed at the corner of the bottom surface of the chamber, and is not recommended to be placed on the main test surface of the chamber. +- g. To prevent the metal door frame from being exposed when the chamber door is closed, it is recommended that the door frame be wrapped with RF absorbing materials instead of metal aluminium foil. + +## **B.3 Support structure and walls** + +The support structure and walls of the PIM test laboratory shall provide a suitably adhered inner surface for the RF absorbing material. Support structures and walls should also help to control the temperature, pressure, humidity, or other environmental conditions of the experiment. + +Materials and construction methods will vary depending on the application. For most applications, wood and plywood structures or cement structures can meet the requirements, cement bricks can provide better support, and the disadvantage is higher cost. Designing support structures and walls requires consideration of the following: + +- a. Avoid the use of metals as much as possible, especially the use of overlapping metal sheets. +- b. The wooden support structure can be screwed and the screw connection is more reliable than nail fixing. Metal parts are not allowed to be directly connected to each other, even within the support structure. +- c. The actual size of the absorbing material must be determined before the structural design is completed. +- d. The laboratory should be large enough to keep the test antenna sufficiently far from any RF absorbing material to avoid coupling between the radiating antenna and the absorbing material. +- e. Evaluate potential sources of passive intermodulation, such as hinges, fasteners, fixtures, fire sprinklers, mounting accessories, etc. + +## **B.4 RF shielding** + +The question of whether to use RF shielding depends on the application requirements. RF shielding ensures the tester's electromagnetic radiation safety and provides a low RF floor noise for the test site. You can determine whether RF shielding is required by calculating the power density. By calculation, it may be found that the RF level after the RF absorbing material is very low and therefore safe. Before the final test plan or procedure is passed, it is often necessary to investigate the RF environment around the laboratory. + +The method of RF shielding is also dependent on the application. A thin aluminium foil or aluminium plate is usually applied to the outer surface of the laboratory structure. Aluminium foil can be securely bonded with adhesive products. A plastic insulating material is placed on the edge of each aluminium plate to prevent direct contact between any aluminium plates. The small gap between the aluminium plates should not pass any RF energy except for the extremely small wavelengths compared to the aluminium plate gap. Although the RF power at the RF shield may be extremely low, it is still necessary to avoid selecting materials that may cause intermodulation, such as metal mesh. + +## **B.5 RF chamber evaluation** + +The radiation energy from AUT may generate PIM products on the surrounding objects, and the PIM products can be reflected into the AUT. At the same time extraneous RF signals may also distort the PIM test result. The role of the anechoic chamber is to isolate these unwanted RF signals and to minimize reflections by the absorbing material on the inside walls. Because of this the performance of a PIM test chamber is built up by the contributions of the PIM level magnitude from absorbers and from the shielding enclosure. + +The absorbers and shielding enclosure of chambers may also produce PIM. Figure B.1 shows the PIM generated from a test chamber. When the RF signal $S_{an}$ radiated by the AUT transmits to the absorbing material, the PIM product $PIM_{ab}$ is produced by the absorbing material. Meanwhile, part of the energy through the absorbers is reflected by the shielding enclosure that produces another kind of PIM, $PIM_{sh}$ . These PIM products can be amplified by the antenna gain and the measuring power, and can interfere with the test results causing measurement uncertainties. + +![Diagram of a test chamber showing PIM products. The chamber is lined with 'Absorbers' (represented by sawtooth patterns) and enclosed by a 'Shielding enclosure' (represented by a solid outer boundary). An antenna on the left emits a signal S_an. Two arrows point to the absorbers: one labeled PIM_ab (representing PIM from the absorbers) and another labeled PIM_sh (representing PIM from the shielding enclosure). The diagram is labeled K.149(20)_FB.1 at the bottom right.](c85ded401105f62f2d6ff26b3b5eb4af_img.jpg) + +Diagram of a test chamber showing PIM products. The chamber is lined with 'Absorbers' (represented by sawtooth patterns) and enclosed by a 'Shielding enclosure' (represented by a solid outer boundary). An antenna on the left emits a signal S\_an. Two arrows point to the absorbers: one labeled PIM\_ab (representing PIM from the absorbers) and another labeled PIM\_sh (representing PIM from the shielding enclosure). The diagram is labeled K.149(20)\_FB.1 at the bottom right. + +**Figure B.1 – PIM products from a test chamber** + +The proposed methods of testing the maximum measurable antenna gain of chamber are as follows: + +- a) For small size PIM test chambers, the simple method to evaluate the performance is by using a low PIM omnidirectional antenna as a standard antenna. Omnidirectional antennas usually have a wide beam. When the omnidirectional antenna is placed in the centre of the small chamber, it achieves a full coverage for the chamber. If the measured PIM is close to the noise floor of the PIM instrument, the chamber can be considered qualified. +- b) For large size PIM test chambers which can be used to measure the PIM of high gain antennas, one way is to use a series of high gain antennas, and this is a quite difficult task. On one hand, it is not easy to design a high gain antenna with low PIM. On the other hand, the high gain antennas usually have a narrow beamwidth. This characteristic makes it troublesome to scan each part of the chamber using the high gain antennas. In addition, the multiple movements may change the cable effect on the PIM level. +- c) A chamber evaluation method with one medium gain low PIM antenna. The basic principle of the proposed method is providing gain compensation by changing the measurement distance (between AUT and absorbers). The measurement points in different measurement distances are defined by the 3 dB antenna beamwidth. Chambers can be measured by this method. +- d) It is recommended that a standard antenna be used for acceptance in the test chamber. The PIM3 value of the standard antenna is $-153 \text{ dBc}$ ( $-153 \text{ dBc} \pm 10 \text{ dB}$ ) (@ $2^{*}43 \text{ dBm}$ ). Move the grids on the left, right, and front sides of the antenna by nine positions. The distance between adjacent points is based on the half-wavelength of the centre frequency of the antenna. If the average values at nine positions are used as the reference values and the deviation between the test values at the nine positions and the reference values is less than $\pm 3 \text{ dB}$ , the test result is qualified. + +# Bibliography + +- [b-ITU-R M.1797] Recommendation ITU-R M.1797 (2007), *Vocabulary of terms for the land mobile service*. + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.27-201503-I_PDF-E/raw.md b/marked/K/T-REC-K.27-201503-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..244c52de25829c2c99dc855d2768397adb76c5d5 --- /dev/null +++ b/marked/K/T-REC-K.27-201503-I_PDF-E/raw.md @@ -0,0 +1,811 @@ + + +International Telecommunication Union + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.27** + +(03/2015) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +# --- **Bonding configurations and earthing inside a telecommunication building** + +Recommendation ITU-T K.27 + +ITU-T + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a red lightning bolt striking it, symbolizing telecommunications. To the right of the globe, the text "International Telecommunication Union" is written in blue. + +ITU logo + +International +Telecommunication +Union + + + +## Recommendation ITU-T K.27 + +# Bonding configurations and earthing inside a telecommunication building + +## Summary + +Recommendation ITU-T K.27 provides the procedures for implementing the bonding between metallic bodies and the earthing connections inside a telecommunication building. It provides the bonding configurations and earthing in order to achieve protection against electric shock and to minimize damage of the telecommunication equipment due to lightning flashes, as well as to limit interference between telecommunication equipment installed in the same building. Examples of the metallic bodies considered in this Recommendation are: equipment frame, shield of cables, metallic structure of the building, protective earth conductor, bonding conductors, earthing electrodes. This Recommendation provides several possibilities of bonding configurations and discusses their advantages and disadvantages. The theory of bonding and earthing is also presented and is used as rationale for the development of the procedures. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.27 | 1991-03-18 | V | 11.1002/1000/1397 | +| 2.0 | ITU-T K.27 | 1996-05-08 | 5 | 11.1002/1000/3349 | +| 3.0 | ITU-T K.27 | 2015-03-01 | 5 | 11.1002/1000/12405 | + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2015 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|---------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 2 | +| 3.1 Terms defined elsewhere ..... | 2 | +| 3.2 Terms defined in this Recommendation..... | 3 | +| 4 Abbreviations and acronyms ..... | 4 | +| 5 Conventions ..... | 4 | +| 6 Principles of bonding and earthing..... | 5 | +| 6.1 Summary of theory ..... | 5 | +| 6.2 Implementation principles ..... | 6 | +| 6.3 Protection against electric shock ..... | 8 | +| 6.4 Protection against lightning..... | 8 | +| 6.5 Functional earthing..... | 9 | +| 7 Power distribution..... | 9 | +| 7.1 AC power distribution ..... | 9 | +| 7.2 DC power distribution ..... | 10 | +| 8 Comparison between IBN and mesh-BN installations ..... | 11 | +| 9 Maintenance of bonding networks..... | 12 | +| 10 Examples of connecting equipment configurations to the CBN ..... | 12 | +| Annex A – Brief theory of bonding and earthing networks..... | 13 | +| A.1 Overview ..... | 13 | +| Annex B – Examples of bonding configurations ..... | 16 | +| B.1 Mesh-BN ..... | 16 | +| B.2 Mesh-IBN with a bonding mat configuration ..... | 18 | +| B.3 Star or sparse mesh-IBN with isolation of DC power return ..... | 20 | +| Bibliography..... | 23 | + +# Introduction + +The transition from analogue to complex digital telecommunication systems has indicated inadequacies with earthing techniques of the past and has therefore caused renewed interest in bonding and earthing techniques and their impact on electromagnetic compatibility (EMC). Consequently, there is a need for an ITU-T Recommendation on bonding configurations and earthing inside a telecommunication building. + +Within the field of EMC, regulations restricting electromagnetic emissions must be satisfied, and for acceptable performance, equipment must possess a specific level of immunity. Electromagnetic compatibility may be achieved by the construction of a common, earthed, conductive shielding network or structure referred to as the common bonding network (CBN). The CBN is the principal bonding and earthing network inside the building. The CBN may be augmented with nested shielding structures having "single point" connections to the CBN. These single point connected structures will be referred to as isolated bonding networks (IBNs). In a telecommunication building, the bonding and earthing network takes the form of the CBN, to which equipment is attached by multiple connections (mesh-BN) or by a single point connection (IBN). The selection of the bonding configuration has an important influence on the responsibility for achieving EMC. A defined bonding configuration permits clear, structured cable routing and earthing. It facilitates control of electromagnetic emissions and immunity, which is especially important for buildings containing newly installed and existing equipment. A comparison of these approaches (IBN and mesh-BN), including their attributes as functions of frequency are discussed in clause 8 and Annex A. As part of its shielding function, the bonding and earthing network provides for personnel safety and lightning protection, and helps control electrostatic discharge (ESD). + +Since several different bonding and earthing configurations have been used, and it is desirable to promote standardization by defining generic versions of these configurations. Although there are differences among the configurations, there are many important common aspects. These are discussed in this Recommendation. In addition, three example configurations are described. + +## Recommendation ITU-T K.27 + +# Bonding configurations and earthing inside a telecommunication building + +# 1 Scope + +Experience in the operation of telecommunication centres shows that the use of a bonding and earthing network that is coordinated with equipment capability and with electrical protection devices, has the following attributes: + +- promotes personnel safety and reduces fire hazards; +- enables signalling with earth return; +- minimizes service interruptions and equipment damage; +- minimizes radiated and conducted electromagnetic emissions; +- reduces radiated and conducted electromagnetic susceptibility; +- improves system tolerance to discharge of electrostatic energy, and lightning interference. + +Within this framework, this Recommendation: + +- a) is a guide to bonding and earthing of telecommunication equipment in telephone exchanges and similar telecommunication switching centres; +- b) is intended to comply with safety requirements imposed by [IEC 60364-4-41] and [IEC 60364-5-54] or national standardizing bodies on AC power installations; +- c) can be used for installation of new telecommunication centres, and, if possible, for expansion and replacement of systems in existing centres; +- d) treats coordination with external lightning protection, but does not provide details of protective measures specific to telecommunication buildings; +- e) addresses the shielding contribution of the effective elements of the building; +- f) addresses shielding provided by cabinets, cable trays and cable shields; +- g) is intended to encourage EMC planning, which should include bonding and earthing arrangements that accommodate installation tests and routine diagnostics; +- h) does not include: + - required values of surge current immunity and insulation withstand voltages; + - limits of radiated and conducted electromagnetic emission or immunity; + - techniques for verifying and maintaining bonding and earthing networks. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.20] Recommendation ITU-T K.20 (2011), *Resistibility of telecommunication equipment installed in a telecommunications centre to overvoltages and overcurrents*. + +- [IEC 60050-604] IEC 60050-604 (1987), *International Electrotechnical Vocabulary. Chapter 604: Generation, transmission and distribution of electricity – Operation.* +- [IEC 60050-826] IEC 60050-826 (2004), *International Electrotechnical Vocabulary. Part 826: Electrical installations.* +- [IEC 60364-4-41] IEC 60364-4-41 (2005), *Low-voltage electrical installations – Part 4-41: Protection for safety – Protection against electric shock.* +- [IEC 60364-5-54] IEC 60364-5-54 (2011), *Amendment 1 – Low-voltage electrical installations – Part 5-54: Selection and erection of electrical equipment – Earthing arrangements and protective conductors.* +- [IEC 62305-3] IEC 62305-3 (2010), *Protection against lightning - Part 3: Physical damage to structures and life hazard.* + +# 3 Definitions + +In this Recommendation, definitions with respect to earthing already introduced by the IEC in [IEC 60050-604] and [IEC 60050-826] are used to maintain conformity. For convenience, they are reproduced in clause 3.1. Definitions specific to telecommunication installations, and not covered by the IEC, are added in clause 3.2. + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 earth** [IEC 60050-826]: The conductive mass of the earth, whose electric potential at any point is conventionally taken as equal to zero (in some countries the term "ground" is used instead of "earth"). + +**3.1.2 earth electrode** [IEC 60050-826]: A conductive part or a group of conductive parts in intimate contact with and providing an electrical connection with earth. + +**3.1.3 earthing conductor** [IEC 60050-826]: A protective conductor connecting the main earthing terminal or bar to the earth electrode. + +**3.1.4 earthing network** [IEC 60050-604]: The part of an earthing installation that is restricted to the earth electrodes and their interconnections. + +**3.1.5 equipotential bonding** [IEC 60050-826]: Electrical connection putting various exposed conductive parts and extraneous conductive parts at a substantially equal potential. + +**3.1.6 equipotential bonding conductor** [IEC 60050-826]: A protective conductor for ensuring equipotential bonding. + +**3.1.7 main earthing terminal** [IEC 60050-826]: A terminal or bar provided for the connection of protective conductors, including equipotential bonding conductors and conductors for functional earthing, if any, to the means of earthing. + +**3.1.8 neutral conductor (N)** [IEC 60050-826]: A conductor connected to the neutral point of a system and capable of contributing to the transmission of electrical energy. + +**3.1.9 protective conductor (PE)** [IEC 60050-826]: A conductor required by some measures for protection against electric shock by electrically connecting any of the following parts: + +- exposed conductive parts; +- extraneous conductive parts; +- main earthing terminal; + +- earth electrode; +- earthed point of the source or artificial neutral. + +**3.1.10 PEN conductor** [IEC 60050-826]: An earthed conductor combining the functions of both protective conductor and neutral conductor. + +## 3.2 Terms defined in this Recommendation + +The definitions of BN configurations are illustrated in Figures 1 and 2. + +This Recommendation defines the following terms: + +**3.2.1 bonding network (BN)**: A set of interconnected conductive structures that provides an electromagnetic shield for electronic systems and personnel at frequencies from DC to low RF. The term "electromagnetic shield", denotes any structure used to divert, block or impede the passage of electromagnetic energy. In general, a BN need not be connected to earth but all BNs considered in this Recommendation will have an earth connection. + +**3.2.2 common bonding network (CBN)**: The CBN is the principal means for effecting bonding and earthing inside a telecommunication building. It is the set of metallic components that are intentionally or incidentally interconnected to form the principal bonding network (BN) in a building. These components include: structural steel or reinforcing rods, metallic plumbing, AC power conduit, protective conductors (PEs), cable racks and bonding conductors. The CBN always has a mesh topology and is connected to the earthing network. + +**3.2.3 common DC return (DC-C)**: A DC power system in which the return conductor is connected to the surrounding bonding network (BN) at many locations. This BN could be either a mesh-BN (resulting in a DC-C-MBN system) or an isolated bonding network (IBN) (resulting in a DC-C-IBN system). More complex configurations are possible (see clause 7.2). + +**3.2.4 isolated bonding network (IBN)**: A bonding network that has a single point connection (SPC) to either the common bonding network or another isolated bonding network. All IBNs considered here will have a connection to earth via the SPC. + +**3.2.5 isolated DC return (DC-I)**: A DC power system in which the return conductor has a single point connection to a bonding network (BN). More complex configurations are possible, see clause 7.2. + +**3.2.6 mesh-BN (MBN)**: A bonding network in which all associated equipment frames, racks and cabinets, and usually, the DC power return conductor, are bonded together as well as at multiple points to the CBN. Consequently, the mesh-BN augments the common bonding network (CBN). + +**3.2.7 mesh-IBN**: A type of isolated bonding network (IBN) in which the components of the IBN (e.g., equipment frames) are interconnected to form a mesh-like structure. This may, for example, be achieved by multiple interconnections between cabinet rows, or by connecting all equipment frames to a metallic grid (a "bonding mat") extending beneath the equipment. The bonding mat is, of course, insulated from the adjacent common bonding network (CBN). If necessary the bonding mat could include vertical extensions, resulting in an approximation to a Faraday-cage. The spacing of the grid is chosen according to the frequency range of the electromagnetic environment. + +**3.2.8 single point connection (SPC)**: The unique location in an IBN where a connection is made to the CBN. In reality, the SPC is not a "point" but, of necessity, has sufficient size to accommodate the connection of conductors. Usually, the SPC takes the form of a copper bus-bar. If cable shields or coaxial outer conductors are to be connected to the SPC, the SPC could be a frame with a grid or sheet metal structure. + +**3.2.9 SPC window (SPCW)**: The interface or transition region between an isolated bonding network (IBN) and the common bonding network (CBN). Its maximum dimension is typically 2 metres. The SPC bus-bar (SPCB), or frame, lies within this region and provides the interface between + +IBN and CBN. Conductors (e.g., cable shields or DC return conductors) that enter a system block and connect to its IBN must enter via the SPCW and connect to the SPCB or frame. + +**3.2.10 star-IBN:** A type of isolated bonding network (IBN) comprising clustered or nested IBNs sharing a common single point connection (SPC). + +**3.2.11 system block:** All the equipment whose frames and associated conductive parts form a defined bonding network (BN). + +![Figure 1 shows two bonding network configurations: Star topology and Mesh topology. The Star topology diagram shows six rectangular blocks (Rack, equipment, module) connected to a single central point by lines (Bonding conductor). The Mesh topology diagram shows six rectangular blocks arranged in a 2x3 grid, connected to each other by lines (Bonding conductor) in a mesh pattern. A legend below the diagrams shows a single rectangle labeled 'Rack, equipment, module' and a line labeled 'Bonding conductor'. The label 'K.27(15)_F01' is present near the bottom right of the mesh diagram.](e6df2733626a85205c1db682e6259c46_img.jpg) + +Star topology + +Mesh topology + +K.27(15)\_F01 + +— Rack, equipment, module + +— Bonding conductor + +Figure 1 shows two bonding network configurations: Star topology and Mesh topology. The Star topology diagram shows six rectangular blocks (Rack, equipment, module) connected to a single central point by lines (Bonding conductor). The Mesh topology diagram shows six rectangular blocks arranged in a 2x3 grid, connected to each other by lines (Bonding conductor) in a mesh pattern. A legend below the diagrams shows a single rectangle labeled 'Rack, equipment, module' and a line labeled 'Bonding conductor'. The label 'K.27(15)\_F01' is present near the bottom right of the mesh diagram. + +**Figure 1 – Bonding network configurations forming a system block** + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|------------------------------------------| +| BN | Bonding Network | +| CBN | Common Bonding Network | +| EMC | ElectroMagnetic Compatibility | +| ESD | ElectroStatic Discharge | +| IBN | Isolated Bonding Network | +| MBN | Mesh-Bonding Network | +| N | Neutral | +| PCB | Printed Circuit Board | +| PEN | Protective (earth) and Neutral conductor | +| SPC | Single Point Connection | +| SPCB | Single Point Connection Bus bar | +| SPCW | Single Point Connection Window | + +# **5 Conventions** + +None. + +# **6 Principles of bonding and earthing** + +## **6.1 Summary of theory** + +Bonding and earthing refer to the construction and maintenance of bonding networks (BNs) and their connection to earth. In this Recommendation, the acronym BN implies that a connection to earth exists. Also, BN is used to refer to common bonding networks (CBNs) and isolated bonding networks (IBNs) collectively. + +The primary purpose of a BN is to help shield people and equipment from the adverse effects of electromagnetic energy in the DC to low RF range. Typical energy sources of concern are lightning, and AC and DC power faults. Of generally lesser concern are quasi steady-state sources such as AC power harmonics, and "function sources" such as clock signals from digital equipment. All of these sources will be referred to generically as "emitters". People and equipment that suffer adversely from the energy from the emitters will be referred to as "susceptors". The coupling between a particular emitter and a particular susceptor may be characterized by a transfer function. The purpose of a BN is to reduce the magnitude of the transfer function to an acceptable level. This may be achieved by appropriate design of the CBN, and the mesh-BNs (MBNs) and IBNs attached to that CBN. Theoretical and quantitative aspects are discussed in Annex A. Practical aspects are discussed below. + +Other purposes of a BN are to function as a "return" conductor in some signalling applications, and as a path for power fault currents. The capability of the BN to handle large currents helps to rapidly de-energize faulted power circuits. Also the BN, and its connection to earth, is used in "ground return" signalling (see clause 6.5). + +![Star configuration diagram showing three racks connected to a single point on the CBN via Star-IBN. The connection point is labeled SPCW. A note indicates the connection 'May be of zero length'. Mesh configuration diagram showing three racks connected to the CBN via Mesh-IBN at a single point labeled SPCW. Mesh configuration diagram showing three racks connected to the CBN at multiple points via Mesh-IBN.](d4af765160d04ecef538e5066006dc77_img.jpg) + +| | | Star configuration | Mesh configuration | +|------------------------------------|----------------|----------------------------------------------------------|-----------------------------| +| Integration of the BN into the CBN | Single point |

Star-IBN

SPCW

May be of zero length

|

Mesh-IBN

SPCW

| +| | Multiple point |

Not applicable

|

Mesh-BN

| + +Rack, equipment, module, etc. + +Nearby elements of CBN + +Bonding conductor + +Connection to CBN + +BN Bonding network + +CBN Common bonding network + +IBN Isolated bonding network + +SPCW Single point connection window + +K.27(15)\_F02 + +Star configuration diagram showing three racks connected to a single point on the CBN via Star-IBN. The connection point is labeled SPCW. A note indicates the connection 'May be of zero length'. Mesh configuration diagram showing three racks connected to the CBN via Mesh-IBN at a single point labeled SPCW. Mesh configuration diagram showing three racks connected to the CBN at multiple points via Mesh-IBN. + +**Figure 2 – Connection of system block to the CBN** + +## 6.2 Implementation principles + +### 6.2.1 Implementation principles for the CBN + +The theoretical concepts of Annex A are confirmed by practical experience and lead to the general principles listed below. A consequence of applying these principles is that the number of conductors and interconnections in the CBN is increased until adequate shielding is achieved. Concerning the important issue of electric shock, the following implementation principles apply to mitigation of electric shock as well as to equipment malfunction. Electric shock is discussed further in clause 6.3. + +- a) All elements of the CBN shall be interconnected. Multiple interconnections resulting in a three-dimensional mesh are especially desirable. Increasing the number of CBN conductors and their interconnections increases the CBN shielding capability and extends the upper frequency limit of this capability. +- b) It is desirable that the egress points for all conductors leaving the building (including the earthing conductor), be located close together. In particular, the AC power entrance facilities, telecommunication cable entrance facilities, and the earthing conductor entry point, should be close together. + +- c) The facility should be provided with a main earthing terminal located as close as possible to the AC power and telecommunication cable entrance facilities. The main earthing terminal shall connect to: + - an earthing electrode(s) via a conductor of shortest length; + - the neutral conductor of the AC power feed (in TN systems); + - cable shields (at the cable entrance) either directly or via arresters or capacitors if required by corrosion considerations. +- d) The CBN shall be connected to the main earthing terminal. Multiple conductors between CBN and the main earthing terminal are desirable. +- e) As contributors to the shielding capability of the CBN, interconnection of the following items of the CBN is important: + - metallic structural parts of the building including I-beams and concrete reinforcement where accessible; + - cable supports, trays, racks, raceways and AC power conduit. +- f) The coupling of surges into indoor cabling (signal or power) is reduced, in general, by running the cables in close proximity to CBN elements. However, in the case of external surge sources, the currents in the CBN will tend to be greater in peripheral CBN conductors. This is especially true of lightning down-conductors. Thus, it is best to avoid routing cables in the periphery of the building. When this is unavoidable, metallic ducts that fully enclose the cables may be needed. In general, the shielding effect of cable trays, etc., is especially useful, and metallic ducts or conduit that fully enclose the cables provide near perfect shielding. +- g) In steel frame high-rise buildings, advantage may be taken of the shielding effect that the steel frame provides against lightning strokes. For cables extending between floors, maximum shielding is obtained by locating the cables near the centre of the building. However, as implied above, cables enclosed in metallic ducts may be located anywhere. +- h) Where the facility to use over-voltage primary protection [ITU-T K.20] on telecommunication wires is provided, it should have a low impedance connection to the cable shield, if it exists, and also to the surrounding CBN. +- i) Over-voltage protectors may be provided at the AC power entrance facility if the telecommunication building is located in an area where power lines are exposed to lightning. These protectors should be bonded with low impedance to the CBN. +- j) Mechanical connections, in a protection path of the CBN, whose electrical continuity is questionable shall be bypassed by jumpers that are visible to inspectors. These jumpers shall comply with IEC requirements for safety. However, for EMC applications, the jumpers should have low impedance. +- k) The CBN facilitates the bonding of cable shields or outer conductors of coaxial cables at both ends by providing a low impedance path in parallel and in proximity to the cable shields and outer conductors. Thus, most of the current driven by potential differences is carried by the highly conductive members of the CBN. Disconnection of one cable shield for inspection should minimally affect the current distribution in the CBN. + +### 6.2.2 Implementation principles for a mesh-BN + +The main feature of a mesh-BN is the interconnection, at many points, of cabinets and racks of telecommunication and other electrical equipment, and also multiple interconnections to the CBN. + +If the outer conductor of a coaxial cable interconnection between mesh-BN equipment has multiple connections to the CBN, it may need additional shielding. If the shielding provided by a cable tray is + +insufficient, additional shielding may be provided by use of shielded coaxial cable ("triax"), enclosing ducts, or conduit. + +Bonding methods, in increasing order of EMC quality are: screw fastenings, spot welds, and welded seams. The highest level of EMC shielding is provided by equipment cabinets and any sheet-metal enclosures within these cabinets. + +A proven countermeasure to undesirable emission or reception of electromagnetic energy, especially at high frequencies, is a shield that totally encloses the electronic circuit. Effective shielding of cables, especially when the shields are extensions of shielding cabinets, depends on shielding material, shield geometry, and especially the connection of the shield to the cabinet panels at which the shield terminates. + +It is easy to add shielding to a mesh-BN configuration. The need for additional shielding may arise for example, if a broadcast transmitter were installed nearby. + +In some situations, it may be advantageous to augment the mesh-BN by connecting all equipment frames of a system block to a conductive grid (a bonding mat) located either below or above a collection of equipment cabinets. This optional use of a bonding mat is shown in Figure B.1. + +### **6.2.3 Implementation principles for an IBN** + +The main feature of an IBN is that it is isolated from the surrounding CBN except for a single point connection where conductors entering the system block enter via the transition region between the IBN and CBN (see definition of single point connection window (SPCW)). + +Within the confines of an IBN, the importance of multiple interconnections between cabinets and racks, etc., depends on the details of DC power distribution and signal interconnection. For example, if the DC power return conductor has multiple connections to cabinet frames, then multiple interconnection of cabinet frames and racks is desirable for the following reason: it will tend to reduce surge coupling in the event of a DC fault in equipment within the IBN. + +Concerning cable shields of twisted pair cables, if a shield is left open-circuit at the end that terminates on IBN equipment, while the other end is connected to the CBN, surges in the CBN may result in induced common mode surges on the pairs in that cable. If those pairs terminate on devices that can operate satisfactorily in the presence of a steady state common mode (e.g., opto-isolators, transformers, or surge protectors), and if those devices can also withstand common mode surges, then there may be an advantage in having the electrostatic shielding afforded by an open circuited shield. + +In the case of coaxial cable, the outer conductor will, of necessity, terminate on the interface circuits at each end. Interface circuits containing transformers or opto-isolators may be used to isolate the outer conductor. If a shielded cable or waveguide enters the IBN from the CBN, the most generally effective strategy is to connect each end of the shield or waveguide to the equipment frame and to bond the shield or waveguide to the single point connection. + +## **6.3 Protection against electric shock** + +A densely interconnected BN, together with its connection to earth, substantially reduces the likelihood of significant voltages appearing between adjacent metallic components. However, additional measures need to be taken, especially in regard to AC power distribution (see clause 7.1). [IEC 60364-4-41] and [IEC 60364-5-54] discuss protection against electric shock, and installations should conform to its recommendations. + +## **6.4 Protection against lightning** + +A CBN conforming to clause 6.2.1 should adequately shield against lightning surges arriving at the building on conductors such as cable shields and power lines. However, in the event of a direct stroke to the building, the CBN may not provide sufficient shielding. Consequently, buildings without steel frames or reinforcements may require external lightning protection; especially so if the building has + +a radio tower on its roof. Concerning the protective measures against the effects of a direct lightning stroke to a building, refer to [IEC 62305-3]. Where necessary to further reduce risk, these protective measures may have to be enhanced, e.g., by conductive roof layers, closer spacing of down-conductors, interconnection of the reinforcement of concrete buildings, and interconnection of metallic façade elements. It is advantageous to introduce all conductive elements of services, e.g., cables and pipes, into the building at one location and in close proximity. + +## 6.5 Functional earthing + +Telecommunication techniques sometimes use circuits for signalling with earth return, e.g., lines with ground start, three wire inter-exchange connection, etc. Equipment interconnected by these circuits needs functional earthing. The signalling range is normally determined by the resistance of the current path. Most of this resistance is contributed by the earth electrodes. The performance provided by the earthing network via the main earthing terminal is generally sufficient for this signalling purpose. + +# 7 Power distribution + +AC and DC power distribution in telecommunication buildings should be designed to limit coupling to telecommunication circuits arising from: + +- mutual impedance of shared conductors; +- mutual inductive coupling (especially during short circuit conditions); +- common source impedances. + +## 7.1 AC power distribution + +It is recommended that the indoor mains installation within a telecommunication building be of type TN-S in order to improve the EMC performance of the telecommunication installation. This requires that there shall be no protective (earth) and neutral (PEN) conductor within the building. Consequently, a three-phase network within a telecommunication building is, physically, a five-wire installation (L1, L2, L3, N, PE). + +Depending on the type of outdoor mains distribution network serving a telecommunication building, one of the following requirements shall apply: + +- a) Service by a TN-S section of the outdoor mains distribution network: + - 1) solely the protective conductor (PE) shall be connected to the main earthing terminal (see Figure 3, mode 1). +- b) Service by a TN-C section of the outdoor mains distribution network: + - 1) the PEN conductor shall be connected to the main earthing terminal only; + - 2) from the main earthing terminal to and within customer locations inside the building, the neutral conductor (N) shall be treated as a live conductor; + - 3) a dedicated PE shall be provided (see Figure 3, mode 2). +- c) Service by a TT or IT section of the outdoor mains distribution network: + - 1) the PE shall be derived via the main earthing terminal from the earthing network; + - 2) the dimensioning of the PE shall follow the rules of the TN-S system. + +If the outdoor mains distribution is of type IT or TT, a separation transformer dedicated to that building allows for the recommended TN-S installation. In this case the indoor mains installation must conform to Figure 3, mode 1. + +## 7.2 DC power distribution + +In telecommunication buildings, DC power is generally distributed from a centralized DC power plant, with the positive terminal connected to the CBN. This polarity is chosen to minimize corrosion in the outside cable plant. There may be exceptions for specific transmission systems. + +The DC power return network may be connected to its surrounding BNs at a single point only. This case will be referred to as an "isolated DC return" system (DC-I). + +![Figure 3: Arrangements for the transition from the outdoor mains distribution system to the indoor AC distribution systems other than TN-S. The figure shows three modes: Mode 1 (TN-S/TN-S), Mode 2 (TN-C/TN-S), and Mode 3 (IT/IT or TT/TT). Each mode illustrates the connection between outdoor mains distribution, indoor AC distribution, and a DC power distribution system including PE, DC-return, and Ring conductor connected to a main earthing terminal.](1a827b10290f33d4fec04d0e8ef7a897_img.jpg) + +**Mode 1: TN-S/TN-S** + +The diagram shows the transition from an outdoor TN-S distribution system to an indoor TN-S installation. The outdoor system has separate PE and N conductors. The indoor installation also has separate PE and N conductors. The DC power distribution system includes a PE conductor connected to the main earthing terminal, a DC-return conductor, and a ring conductor. The PE conductor is connected to the indoor PE conductor. + +**Mode 2: TN-C/TN-S** + +The diagram shows the transition from an outdoor TN-C distribution system to an indoor TN-S installation. The outdoor system has a combined PEN conductor. The indoor installation has separate PE and N conductors. The DC power distribution system includes a PE conductor connected to the main earthing terminal, a DC-return conductor, and a ring conductor. The PE conductor is connected to the indoor PE conductor. + +**Mode 3: IT/IT or TT/TT** + +The diagram shows the transition from an outdoor IT or TT distribution system to an indoor IT or TT installation. The outdoor system has separate PE and N conductors. The indoor installation also has separate PE and N conductors. The DC power distribution system includes a PE conductor connected to the main earthing terminal, a DC-return conductor, and a ring conductor. The PE conductor is connected to the indoor PE conductor. + +NOTE – Mode 1 is obligatory if a separation transformer is dedicated to the building and the TN-S system consequently originates at the transformer load side. + +K.27(15)\_F03 + +Figure 3: Arrangements for the transition from the outdoor mains distribution system to the indoor AC distribution systems other than TN-S. The figure shows three modes: Mode 1 (TN-S/TN-S), Mode 2 (TN-C/TN-S), and Mode 3 (IT/IT or TT/TT). Each mode illustrates the connection between outdoor mains distribution, indoor AC distribution, and a DC power distribution system including PE, DC-return, and Ring conductor connected to a main earthing terminal. + +**Figure 3 – Arrangements for the transition from the outdoor mains distribution system to the indoor AC distribution systems other than TN-S** + +Alternatively, the DC return may connect to the BN at multiple points (in which case some DC current will be conducted by the BN). This system will be referred to as a "DC return common to a BN" and denoted by "DC-C-BN". Typical configurations are DC-C-CBN (DC return common to the CBN), and DC-C-IBN (DC return common only to an IBN). Also, a DC return could, for example, traverse both the CBN and an IBN, and be common to the CBN but isolated from the IBN. This case is denoted by DC-C-CBN: DC-I-IBN. These are discussed in Annex B. Other more complicated interconnections of BNs and DC returns are also in use. + +The advantage of a DC-C-BN system is that it cannot support a DC feed common-mode and hence unwanted coupling via this mode cannot occur. On the other hand, there will be coupling between the BN and the DC feed. The advantage of the DC-I-IBN system is that it avoids BN to DC feed coupling. However, it supports a common-mode and may introduce unwanted coupling. The choice between the two systems depends on the overall design strategy. Some recommendations are given below. + +A DC-C-CBN feed may be used in systems in which the DC feed-to-CBN coupling has been minimized by the following measures: + +- DC feed conductors have large cross-sections enabling them to carry high currents with minimal temperature rise; +- voltage drop at maximum load current is low; +- there is low source impedance, and low mutual impedance between the branches of the DC feed system. + +The use of a DC-I feed results in a much lower DC feed-to-CBN coupling and is preferable in DC distribution networks designed with: + +- loads in more than one system of electronic equipment (i.e., shared battery plant); and +- loads that are sensitive to transients occurring during short circuit conditions. + +# **8 Comparison between IBN and mesh-BN installations** + +The advantage of installing equipment in an IBN is that a high level of shielding is attainable from DC through tens of kHz or perhaps hundreds of kHz depending on the size of the IBN (see clause A.1.2). The reason is that, within this frequency range, the single point connection between the IBN and CBN results in negligible current flowing between CBN and IBN. Some digital switches are designed specifically for installation within an IBN. + +Mesh-IBNs and star-IBNs are both currently in use. Clause B.2 describes a mesh-IBN in the form of a "bonding-mat", and clause B.3 describes a star-IBN system. Sparsely interconnected mesh-IBNs have also been used successfully, and this is mentioned in clause B.3. + +To limit the risk of electric shock between an IBN and the surrounding CBN, it is necessary to limit the size of the IBN (both horizontal and vertical extent). Passageways that form the boundary between IBN and CBN, should have a minimum width imposed. + +Disadvantages of IBN installation are cable routing restrictions and the additional expense (compared to mesh-BN) of maintaining the isolation. + +The advantage of installing equipment in a mesh-BN configuration is that equipment frames may be connected to the surrounding CBN without restriction. Also, shielded cables and coaxial cables may be routed, and their shields or outer conductors connected to cabinet frames, without restriction. If the CBN design and equipment susceptibility has been coordinated, the CBN provides shielding from DC through several megahertz. A mesh-BN installation also has maintenance advantages as described in clause 9. + +A disadvantage of the mesh-BN installation is the need for quantitative design procedures and appropriate immunity data for equipment. + +# **9 Maintenance of bonding networks** + +One advantage of mesh-BN installation is that small changes that occur in the CBN generally have only a small effect on its shielding capability. Moreover, when necessary, additional shielding may be obtained by introduction of additional conductors (e.g., bonding conductors, cable trays, and conduit). Such modifications are usually straightforward. + +IBN systems are more difficult to maintain, because craft-person activity is liable to result in inadvertent interconnections between IBN and CBN, violating the desired single point connection, and introducing surge currents into the IBN. Closely related to this is maintenance of DC-I power systems. Verification of single point connection in a DC-I system is facilitated if this connection is made with a conductor, around which, a DC clamp-on ammeter can be clamped. Zero current confirms single point connection. + +It is recommended that systematic verification be performed on all bonding configurations and earthing connections inside a telecommunication building. + +# **10 Examples of connecting equipment configurations to the CBN** + +The bonding configuration that is used depends upon the type of equipment to be connected to the CBN. + +The following three examples are described in Annex B: + +- 1) mesh-BN (see clause B.1); +- 2) mesh-IBN with a bonding mat configuration (see clause B.2); +- 3) star, or sparse mesh-IBN with isolation of DC power return (see clause B.3). + +# Annex A + +## Brief theory of bonding and earthing networks + +(This annex forms an integral part of this Recommendation.) + +## A.1 Overview + +The basic theoretical notions of shielding apply to the entire electromagnetic spectrum extending from DC through microwave frequencies. The essence of these basic notions is represented by the circuit model of Figure A.1 a). The description of energy sources as "emitters", and susceptible equipment (and people) as "susceptors" is taken from [b-Keiser]. In Figure A.1 a), $V_{em}$ is the frequency domain representation of the emitter (e.g., a Laplace or Fourier transform), and $Z_{em}$ is the emitter source impedance. The susceptor is represented by its impedance $Z_{su}$ . The electromagnetic interaction between emitter and susceptor is modelled by a two-port network (port A with terminals A0, and A1, and port B with terminals B0, and B1). In Figure A.1 a) this two-port is represented by a T-network, but a $\pi$ representation is often useful, as is a Norton equivalent for the emitter. + +Although Figure A.1 a) is a simplification of reality, it is usually an adequate model for any specific emitter-susceptor pair. Moreover, it can be used as the starting point whenever a more complex model is necessary. + +Figure A.1 a) illuminates the two main strategies for increasing the shielding of the susceptor from the emitter: the "short-circuit" and "open-circuit" strategies. It is clear that if $Z_C$ is zero, no energy from the emitter $V_{em}$ can reach the susceptor and $V_{su} = 0$ . The energy that leaves the emitter is "reflected by the short-circuit" and dissipates in the resistive components of $Z_{em}$ and $Z_A$ . (Energy can also be returned to the source but this is not significant here.) Similarly, it is clear that if either $Z_A$ or $Z_B$ are infinite in magnitude (i.e., open circuit), no emitter energy will reach the susceptor (and again $V_{su} = 0$ ). In this case, the energy that leaves the emitter is reflected by the open circuit. Suppose $Z_B$ is the open circuit. Then $Z_B = \infty$ , and the energy will dissipate in the resistive parts of $Z_{em}$ , $Z_A$ and $Z_C$ . Note that in general, $V_{su}$ and all impedances are functions of frequency. + +The two-port in Figure A.1 a) (A1, A0, B1, B0) will be referred to as the shielding network relative to some specific emitter and susceptor. If a different emitter or susceptor were considered, new impedance functions $Z_A$ , $Z_B$ and $Z_C$ would apply. + +A most useful characterization of the shielding network is a frequency domain transfer function. Here, the transfer function $T(\omega)$ will be defined as either $I_{su}(\omega)/V_{em}(\omega)$ or $V_{su}(\omega)/V_{em}(\omega)$ . Thus $T(\omega)$ , as defined here, is a function of $Z_{em}$ and $Z_{su}$ as well as $Z_A$ , $Z_B$ and $Z_C$ . + +To summarize, for each emitter-susceptor pair there is a transfer function, $T(\omega)$ , that characterizes the shielding network. + +Returning to the topic of shielding strategies, note that in general, perfect short and open circuits are not possible to achieve, since the best implementations possess inductance and capacitance respectively. As a result, instead of perfect shielding, the most that can be achieved is a transfer function, $T(\omega)$ , whose magnitude is less than some prescribed value over some prescribed frequency range. + +#### A.1.1 Application to BNs in general + +In typical bonding networks, resistive components are small, and for transient events with spectra in the 1 kHz to 1 MHz range, the shielding network is primarily inductive. Consequently, the general representation of Figure A.1 a) reduces to Figure A.1 b). As noted above, the specific component values depend on a particular emitter-susceptor pair. However, the $L_A$ , $L_B$ and $L_C$ in Figure A.1 b) are constants; they are not functions of frequency. An observation of fundamental importance is as follows: Increasing the number of conductors and interconnections in the BN (especially in the region + +lying between the emitter and susceptor) will, in general, reduce $L_C$ and hence reduce the transfer function of the BN relative to that emitter-susceptor pair. In the limiting case, the susceptor could be given near-total shielding by enclosing it in an unbroken sheet of metal (i.e., a Faraday cage). + +A susceptor may be characterized by a "susceptibility threshold" $I_{sut}(\omega)$ , or $V_{sut}(\omega)$ . Sinusoidal excitation will be assumed, but the following theory may be adaptable to pulse excitation. As an example, consider as a susceptor, equipment whose frame is connected to the CBN at several points. Choose one of these points to be the test point. Suppose the CBN connection at the test point is made by a conductor, around which split-core transformers can be clamped for purposes of excitation and current measurement. Let the current at the test point be sinusoidal with angular frequency $\omega$ and amplitude $I_{sut}(\omega)$ . [ $I_{sut}(\omega)$ real and positive.] + +Suppose that for each $\omega$ , an $I_{sut}(\omega)$ is found such that the equipment functions normally for those $I_{sut}(\omega)$ that satisfy: + +$$I_{sut}(\omega) < I_{sut}(\omega) \text{ for } \omega_1 < \omega < \omega_2$$ + +and functions abnormally for $I_{sut}(\omega)$ that fails to satisfy this inequality. Then $I_{sut}(\omega)$ is the equipment susceptibility threshold for the frequency range $[\omega_1, \omega_2]$ , and for that specific test point and connection configuration. + +Also, suppose a worst-case emitter has been characterized (e.g., let $V_{em}$ be that worst case), then the design of a bonding and earthing network may now be expressed quantitatively as follows: for every emitter-susceptor pair of concern, the network's transfer function shall satisfy the following inequality: + +$$|T(\omega)V_{em}(\omega)| < I_{sut}(\omega) \text{ for } \omega_1 < \omega < \omega_2$$ + +Where: + +$\omega_1$ and $\omega_2$ specify the frequency range of concern. Typically, $\omega_1 \sim 0$ and $\omega_2 \sim 1$ MHz. + +Note that $I_{sut}(\omega)$ is specific to a particular test point, and to the particular configuration of equipment-to-CBN interconnections. It may not apply if the equipment or its interconnections are modified. + +#### A.1.2 Some important features of IBNs + +Isolated bonding networks use an open-circuit shielding strategy. However, because IBNs are invariably installed within an enclosing CBN, short and open circuit strategies operate in cascade as shown in Figure A.1 c). Here, node B2 could, for example, represent the frame of an equipment ( $Z_{su}$ ) that is isolated except for a single point connection to the CBN at node B0. Node B1 represents all of the immediately surrounding CBN metalwork. Capacitor C represents the capacitance between the equipment frame and the surrounding CBN. Figure A.1 c) shows clearly that for low frequencies, $|T(\omega)|$ will be small (it has a zero at $\omega = 0$ ), but at a sufficiently high frequency there will be one or more resonances where $|T(\omega)|$ will have maxima. In the neighbourhood of these resonant frequencies, shielding will be poor. However, if there are no significant emitters in these spectral regions, or if the equipment has additional shielding that is effective in these spectral regions, then no malfunctions will occur. + +![Circuit diagram of the fundamental shielding model. It features a voltage source V_em in series with an impedance Z_em connected between terminals A0 and A1. A series impedance Z_A is connected between A1 and a central node. From this central node, an impedance Z_C is connected to the common reference line (B0). A series impedance Z_B is connected from the central node to terminal B1. At terminal B1, a voltage V_su is indicated, and a current I_su flows through an impedance Z_su connected to terminal B0.](5b8a756d9a71c35f17db8bcb90b438a3_img.jpg) + +a) Fundamental shielding model + +Circuit diagram of the fundamental shielding model. It features a voltage source V\_em in series with an impedance Z\_em connected between terminals A0 and A1. A series impedance Z\_A is connected between A1 and a central node. From this central node, an impedance Z\_C is connected to the common reference line (B0). A series impedance Z\_B is connected from the central node to terminal B1. At terminal B1, a voltage V\_su is indicated, and a current I\_su flows through an impedance Z\_su connected to terminal B0. + +![Circuit diagram of the shielding model for intra-CBN coupling. It features a voltage source V_em in series with an impedance Z_em connected between terminals A0 and A1. A series inductor L_A is connected between A1 and a central node. From this central node, an inductor L_C is connected to the common reference line (B0). A series inductor L_B is connected from the central node to terminal B1. At terminal B1, an impedance Z_su is connected to terminal B0.](812e188283162af0b54fb3e30ffee51b_img.jpg) + +b) Shielding model for intra-CBN coupling + +Circuit diagram of the shielding model for intra-CBN coupling. It features a voltage source V\_em in series with an impedance Z\_em connected between terminals A0 and A1. A series inductor L\_A is connected between A1 and a central node. From this central node, an inductor L\_C is connected to the common reference line (B0). A series inductor L\_B is connected from the central node to terminal B1. At terminal B1, an impedance Z\_su is connected to terminal B0. + +![Circuit diagram of the shielding model for CBN-IBN coupling. It features a voltage source V_em in series with an impedance Z_em connected between terminals A0 and A1. A series inductor L_A is connected between A1 and a central node. From this central node, an inductor L_C is connected to the common reference line (B0). A series inductor L_B is connected from the central node to terminal B1. Between terminal B1 and terminal B2, there is a capacitor C. At terminal B2, an impedance Z_su is connected to terminal B0.](c5655e700cc3e9aac7e9f4f07f30264d_img.jpg) + +c) Shielding model for CBN-IBN coupling + +Circuit diagram of the shielding model for CBN-IBN coupling. It features a voltage source V\_em in series with an impedance Z\_em connected between terminals A0 and A1. A series inductor L\_A is connected between A1 and a central node. From this central node, an inductor L\_C is connected to the common reference line (B0). A series inductor L\_B is connected from the central node to terminal B1. Between terminal B1 and terminal B2, there is a capacitor C. At terminal B2, an impedance Z\_su is connected to terminal B0. + +K.27(15)\_FA.1 + +**Figure A.1 – Shielding model representations** + +# Annex B + +## Examples of bonding configurations + +(This annex forms an integral part of this Recommendation.) + +### B.1 Mesh-BN + +A mesh-BN is a densely interconnected BN in which equipment frames are an extension of the CBN. In this example, which is shown in Figure B.1, the DC power system is of type DC C-MBN. + +The DC power system operating at relatively high voltages (e.g., 400 V DC) shall be balanced about earth (positive and negative) by a resistive divider, whose centre point is connected to earth as shown in Figure B.1. + +#### B.1.1 Components of a mesh-BN + +In mesh-BNs, extensive interconnection among the following conductive elements is recommended: + +- cabinets and cable racks of telecommunication and peripheral equipment; +- frames of all systems housed within the telecommunication building; +- the protective conductor PE of the TN-S type AC power installation; +- all metal parts, which according to [IEC 60364-5-54] must be connected to the protective conductor; +- the main earthing terminal, including earthing conductors and earth electrodes; +- each DC power return conductor along its entire length. + +Multiple interconnections between CBN and each DC return along its entire length is usually a feature of the mesh-BN configuration. The DC return conductor of such a configuration may be entrusted with the functions of protective conductor for systems associated with AC loads or sockets, provided that continuity and reliability complies with [IEC 60364-5-54]. + +#### B.1.2 General design objectives + +Safety requirements supersede all other requirements. To ensure continuity of bonding conductors, reliable connection methods shall be used, e.g., crimping, welding. However, if several options exist for fulfilling safety requirements, only that one shall be used which best coordinates with EMC requirements. + +##### B.1.2.1 Non-telecommunication installations + +Within the whole telecommunication building, there shall be no exception from the TN-S-type AC power installation [IEC 60364-5-54]. This requires, except at the main earthing terminal for a TN-C to TN-S transition at the entrance of the building, that the neutral conductor and protective conductor are nowhere interconnected in the building, neither in permanently connected equipment, nor in equipment connected by plug and socket. + +##### B.1.2.2 Telecommunication equipment and systems + +Telecommunication equipment with electronic circuitry is generally provided with a "potential reference" metallization that extends widely over the surface of the printed circuit boards (PCBs). If PCBs are connectorized, a number of pins are used to interconnect to adjoining cabling, backplanes, or motherboards. At this interface there starts the interconnection to the mesh-BN via equipment frames, shelf-racks, etc. + +![Figure B.1 – Mesh-BN installation inside a telecommunication building. This is a detailed cross-sectional diagram of a multi-story building showing the electrical and bonding infrastructure. The building levels are labeled: Floor n+1, Floor n, Lower floor, and Basement. Key components and connections shown include: + - Support column of the building and Reinforcement. + - 400 V DC equipment and 400 V DC power supply on Floor n+1. + - System block 1 Mesh-BN equipment on Floor n+1, connected to a Bonding ring conductor and a Bonding mat. A note indicates 'Connection of cable shield to the rack is recommended'. + - Interconnection and Interconnected reinforcement between floors. + - Mesh-BN equipment and System block 2 mesh-BN equipment on Floor n. + - AC distribution, PE (Protective Earth), Plumbing, and Aircon units on the Lower floor. + - 48V dc service panel and Frame of dc powerplant on the Basement level. + - Main earthing terminal (PE) on the Basement level, connected to Telecom cables, a Bonding ring conductor (recommended), To earth electrode, and To foundation reinforcement/ring conductor. + - A legend at the bottom right defines the line types: + - DC return conductor (+48 V) [long dash-dot line] + - Interconnected reinforcement and building steel [long dashed line] + - Intra-system cabling [short dashed line] + - Shielded inter-system cabling [line with a circle symbol] + - Bonding conductor [solid line] + - 400 V dc conductor (for +200 V and -200 V, indicated as potential) [dotted line] + - The diagram is labeled K.27(15)_FB.1.](c914f51f4427bc672dd0526cfc90ebe9_img.jpg) + +Figure B.1 – Mesh-BN installation inside a telecommunication building. This is a detailed cross-sectional diagram of a multi-story building showing the electrical and bonding infrastructure. The building levels are labeled: Floor n+1, Floor n, Lower floor, and Basement. Key components and connections shown include: + - Support column of the building and Reinforcement. + - 400 V DC equipment and 400 V DC power supply on Floor n+1. + - System block 1 Mesh-BN equipment on Floor n+1, connected to a Bonding ring conductor and a Bonding mat. A note indicates 'Connection of cable shield to the rack is recommended'. + - Interconnection and Interconnected reinforcement between floors. + - Mesh-BN equipment and System block 2 mesh-BN equipment on Floor n. + - AC distribution, PE (Protective Earth), Plumbing, and Aircon units on the Lower floor. + - 48V dc service panel and Frame of dc powerplant on the Basement level. + - Main earthing terminal (PE) on the Basement level, connected to Telecom cables, a Bonding ring conductor (recommended), To earth electrode, and To foundation reinforcement/ring conductor. + - A legend at the bottom right defines the line types: + - DC return conductor (+48 V) [long dash-dot line] + - Interconnected reinforcement and building steel [long dashed line] + - Intra-system cabling [short dashed line] + - Shielded inter-system cabling [line with a circle symbol] + - Bonding conductor [solid line] + - 400 V dc conductor (for +200 V and -200 V, indicated as potential) [dotted line] + - The diagram is labeled K.27(15)\_FB.1. + +**Figure B.1 – Mesh-BN installation inside a telecommunication building** + +The equipment racks shall be interconnected by low impedance leads or copper bars. Since the mesh-BN technique usually incorporates the DC return conductor into the CBN, the leads or bars can serve as the DC return. The leads or bars of each row have to be interconnected via the shortest route to minimize inductance. One or more DC return conductors may be used to interconnect the system to the centralized common power distribution cabinet or an intermediate power distribution panel. It is recommended that these leads be paired in close proximity with the corresponding negative DC power feed leads to reduce loop areas and enhance EMC. Small gauge DC power conductors should be twisted. + +DC/DC converters generally have one input conductor and one output conductor connected to the mesh-BN. There may be exceptions in specific equipment. + +An independent AC power supply network, derived from the DC supply by DC/AC converters, is best implemented as a TN-S type [IEC 60364-5-54]. + +Unrestricted fastening of the system to the floor and walls provides, in general, sufficient bypassing of stray capacitance for acceptable EMC performance of the system. + +#### **B.1.3 Cabling** + +Regarding EMC, cables can act as antennas, and support common modes that can transport extraneous energy into otherwise well-designed equipment. This antenna and common-mode propagation phenomenon can be mitigated by proper routing and shielding. + +Routing of indoor cabling shall be in close proximity to conductive elements of the CBN and follow the shortest possible path. The shielding afforded by interconnected cable racks, trays, raceways, etc., shall be intentionally used. This shielding is effective only if it is continuous. + +#### **B.1.4 EMC performance** + +Equipment in an appropriately designed mesh-BN configuration, together with the use of DC power distribution with a return that is common to the mesh-BN (i.e., DC-C-MBN), is known to give acceptable EMC performance. + +The incorporation of DC power return conductors into the mesh-BN limits voltage drops caused by short circuit currents in the DC power distribution network. + +### **B.2 Mesh-IBN with a bonding mat configuration** + +A high level of shielding may be obtained by connecting all equipment frames within a system-block into a bonding-mat configuration. This configuration is isolated from the surrounding CBN. The result is a very effective type of mesh-IBN; an example is shown in Figure B.2. + +The technical goals of this installation method are: + +- a) prevention of CBN currents from flowing in the bonding-mat or any other part of the system-block; +- b) achievement of satisfactory EMC performance by controlled interconnection of system-blocks; +- c) provision of bonding and cabling facilities that allow for: + - systematic EMC planning; + - use of well-defined and reproducible EMC test methods. + +The DC power system operating at relatively high voltages (e.g., 400 V DC) shall be balanced about earth (positive and negative) by a resistive divider, whose centre point is connected to earth as shown in Figure B.2. + +![Figure B.2 – Mesh-IBN with bonding mat. This is a 3D perspective diagram showing the electrical bonding and grounding configuration for three new system blocks (1, 2, and 3) and existing equipment (system 4). System block 1 is on the floor, containing 400 V DC equipment and a power supply. It is interconnected by a bonding mat (Bonding mat 1) which is insulated from the floor's steel reinforcement. System block 2 and 3 are below the floor level. Single point connections (SPC1, SPC2, SPC3) are shown between the system blocks and the bonding mat or cable ducts. A low impedance cable duct (CBN element) is also shown. The diagram includes various line styles representing different types of connections: solid for equipotential bonding, dashed for steel reinforcement, dash-dot for unshielded cabling, and dashed with a central line for shielded cabling. Dots along the bonding mat indicate its SPC. A note indicates that connecting the cable screen to the frame is recommended. The diagram is labeled K.27(15)_FB.2.](7133ccf78043568ca62ecbcd43628a4a_img.jpg) + +Figure B.2 – Mesh-IBN with bonding mat. This is a 3D perspective diagram showing the electrical bonding and grounding configuration for three new system blocks (1, 2, and 3) and existing equipment (system 4). System block 1 is on the floor, containing 400 V DC equipment and a power supply. It is interconnected by a bonding mat (Bonding mat 1) which is insulated from the floor's steel reinforcement. System block 2 and 3 are below the floor level. Single point connections (SPC1, SPC2, SPC3) are shown between the system blocks and the bonding mat or cable ducts. A low impedance cable duct (CBN element) is also shown. The diagram includes various line styles representing different types of connections: solid for equipotential bonding, dashed for steel reinforcement, dash-dot for unshielded cabling, and dashed with a central line for shielded cabling. Dots along the bonding mat indicate its SPC. A note indicates that connecting the cable screen to the frame is recommended. The diagram is labeled K.27(15)\_FB.2. + +- SPC Single point connection +- Equipotential bonding conductor +- - - - Steel reinforcement +- · - · Unshielded intra- or inter-system cabling +- - 0 - - Shielded intra- or inter-system cabling +- ..... 400 V dc conductor (for +200 V and -200 V, indicated as potential) +- Dots along the edge at a bonding mat denote its SPC. +Inter-system cabling entering the system block must enter close to the SPC. + +NOTE 1 – System blocks 1, 2 and 3 are new installations conforming to the mesh-IBN method. They may be connected to existing installations (system 4) that use any method of bonding. + +NOTE 2 – The SPC is the only metallic interface between the mesh-IBN and the CBN. It must be directly connected to the reinforcement of the floor. All cables leading to the system enter here. All conductors that are bonded to the mesh-IBN must be connected to the SPC (e.g., cable screens, battery return). + +**Figure B.2 – Mesh-IBN with bonding mat** + +#### B.2.1 Equipment configuration + +The system block comprises equipment agreed upon by the operating agencies and manufacturer(s) to be interconnected to the mesh-IBN (Figure 2). (Note that this agreement facilitates assignment of responsibility to either the supplier or the operating agency.) + +Peripheral equipment denotes equipment location beyond the boundaries of the system block, but which relies functionally on a connection to the IBN. + +Equipment serving air conditioning, lighting, etc., is considered to be external to the system block and may be installed or operated as part of the CBN of the building. + +However, provision for the following is recommended: + +- protective earthing; +- AC power distribution; +- DC power distribution up to the SPC, with the DC power return conductor(s) incorporated into the CBN (DC-C-CBN). + +##### **B.2.1.1 Single point connection** + +It is recommended that the SPC be established in the vicinity of its system, serving as the only connection between IBN and CBN. + +##### **B.2.1.2 Cabling** + +All conductors and cables connecting to the system block shall pass near to the SPC (i.e., through the SPC window). Metalwork near the system block shall be bonded to the SPC to avoid electric shock or flash-over in the event of a lightning strike to the building. Installation of a distribution frame at the SPC is recommended since this facilitates connection of cable shields to the SPC. It is recommended that the shields of all cables passing the SPC be connected to the SPC. + +Alien cables crossing the area of the IBN must be spaced sufficiently apart from cables connecting to the SPC and the system block. + +##### **B.2.1.3 Equipment powered by external AC sources** + +Equipment with IEC class II certification (no PE connected) may be used without restriction within the system block area or at its periphery. + +Equipment with IEC class I certification (relying on PE protection methods) shall be powered via isolating transformers, if not connected to DC/AC converters or AC power sockets belonging to the system block. + +#### **B.2.2 EMC performance** + +Equipment in an appropriately designed mesh-IBN configuration, together with the use of the DC power distribution with a return that is common to the mesh-IBN (i.e., DC-C-IBN), is known to give acceptable EMC performance. + +## **B.3 Star or sparse mesh-IBN with isolation of DC power return** + +In this configuration, the framework of the switch is connected to form either a star or a mesh-IBN (see Figure 1). The cabinet framework and metallic panels are the major components of this IBN (there is no bonding mat). This type of IBN (whether star or mesh) will be denoted by "frame-IBN". The mesh topology is typically achieved by the cross-aisle interconnections afforded by cable trays. The result is a "sparse-mesh" IBN. The single point interconnection between a "frame-IBN" and the CBN is made at the SPC bus-bar located within the SPCW. The SPCW has a fixed dimension that allows the SPCB to be of sufficient size for connecting conductors, while limiting the voltage drop across the SPCB in the event of lightning surges or power system faults. + +An example of this configuration (in its star form) is shown in Figure B.3. The DC feed section leaving the power plant is isolated (i.e., of type DC-I-CBN). This feed splits into a DC-I-IBN feed serving the frame-IBN equipment (the system block), and a DC-C-CBN feed serving mesh-IBN equipment. For the branch feeding the mesh-IBN equipment, a connection between DC return and CBN is made at the SPCB. Beyond the SPCW, this branch is of type DC-C-CBN (i.e., it has multiple connections to the CBN). The DC feed to the frame-IBN equipment need not pass through the SPCW since, within the frame-IBN, it is isolated. However, it is advantageous if most of the DC feed cable is in close proximity to bonding conductors, because this will reduce surge voltages that appear across the isolation barriers of the DC/DC converters on which the DC feed terminates. + +To summarize, the main features of the system are: + +- insulation of the frame-IBN from the surrounding CBN; +- connection of the frame-IBN to the CBN only at the SPCB; +- isolation of the DC return within the frame-IBN and between the power plant and the SPCW. + +Systems of this type (both star and mesh configurations) have shown satisfactory EMC performance. + +Note that this example demonstrates how a bonding and earthing network combines, in one building, systems using IBNs and mesh-BNs. The example also shows how all systems may share one DC power plant. + +The DC power system operating at relatively high voltages (e.g., 400 V DC) shall be balanced about earth (positive and negative) by a resistive divider, whose centre point is connected to earth as shown in Figure B.3. + +#### **B.3.1 The DC power return configuration** + +In the DC power system, the frame-IBN branch and the power plant branch are isolated, resulting in no conductive coupling from the CBN in these branches. However, surges (e.g., lightning and short circuit fault currents) arising in the DC-C-CBN branch (that feeds mesh-BN equipment) can couple *indirectly* into the frame-IBN equipment via the common source impedance presented by the power plant and the DC-I-CBN section. This impedance is kept to a low value by running the –48 V conductors and DC return conductors in close proximity. + +The bonding conductor from the SPCB to the frame of the power plant is run in close proximity to all DC feed conductors in the DC-I-CBN section. This reduces DC feed common-mode surge voltages at the power plant and enables fault clearing in the event of a fault between –48 V and frame in the power plant. + +#### **B.3.2 System installation** + +Cable shields from outside the IBN that terminate within the IBN (i.e., on the system block) have their shields: + +- a) bonded to the frame-IBN and to no other point (such cables shall not extend more than one floor from the SPC); or +- b) bonded to the frame-IBN, bonded to the SPCB, and, outside of the system block, bonded to the CBN. + +Sub-systems that are part of the system block should be located within one floor of the SPC of the main system. This avoids excessive voltage differences between the extremities of the IBN and nearby CBN. + +Peripheral equipment that is to use an IBN and that is located more than one floor from the SPC of the main system shall use a dedicated SPC that is within one floor. The equipment shall be powered through an isolation barrier, e.g., by using DC/DC or AC/DC converters. + +The isolation barrier inside any DC power equipment must have sufficient voltage withstand capability to meet local authority requirements. Installation and wiring of converters should comply with these isolation requirements. + +Framework of equipment, and metal structural components, in a CBN that is located within two metres of an IBN should be bonded to the SPCB for reasons of personnel safety. + +Other equipment that is in the telecommunication building, and that uses the mesh-BN configuration, is installed using the techniques of clause B.1, with or without an isolated DC return. + +#### B.3.3 Maintainability of isolated bonding networks + +IBNs need careful installation and ongoing surveillance to assure isolation. Also, the use of an isolated DC power return may require ongoing monitoring to check its isolation, especially if maintenance work is performed on different or mixed configurations by the same personnel. Violation of isolation during, or as a consequence of, maintenance work, may lead to failures in system operation or even to physical damage during lightning or power fault events. + +![Diagram of Star-IBN with isolation of DC power return across multiple floors (Floor N, Floor N+1, and a lower floor).](b235edb1dbe659e2782c9a0e47775ca4_img.jpg) + +The diagram illustrates a Star-IBN configuration with isolation of DC power return across multiple floors. It shows the following components and connections: + +- Floor N+1:** Support column of building, FGB (Floor ground bar), Mesh-BN equipment (may be more than one floor from SPCB), IBN (DC return conductor not shown), Insulation, Building steel (CBN). +- Floor N:** 400 V DC equipment, 400 V DC power supply, Resistor for mid point connection, Mesh-BN equipment (DC return conductor not shown), SPCB (Single point connection bus-bar), SPCW (Single point connection window), Unshielded twisted pair to switch, Main distributing frame (mesh-BN equipment), IBN. +- Lower floor (may be more than one floor from SPCB):** FGB, Shielded twisted pair to cable entrance facility, Closely coupled, Insulated DC return bus-bar, Frame of principal power plant. +- Vertical Connections:** To earth electrode, Interconnected re-inforcement and building steel. + +**Legend:** + +- Bonding conductor +- - - - Interconnected re-inforcement and building steel +- .-.-.- dc return conductor (+48 V) (-48 V conductor, not shown, closely parallels this) +- ..... 400 V dc conductor (for +200 V and -200 V, indicated as potential) +- .-.-.- Intra- or inter-system cabling + +**Other labels:** + +- FGB Floor ground bar (part of CBN) +- SPCB Single point connection bus-bar +- SPCW Single point connection window + +K.27(15)\_FB.3 + +Diagram of Star-IBN with isolation of DC power return across multiple floors (Floor N, Floor N+1, and a lower floor). + +**Figure B.3 – Star-IBN with isolation of DC power return** + +# Bibliography + +- [b-Keiser] Keiser, B.E. (1987), *Principles of Electromagnetic Compatibility*, 3rd edition, Norwood, MA, Artech House. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|---------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.34-202012-I_PDF-E/raw.md b/marked/K/T-REC-K.34-202012-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..5e946d941cb9ceaa6ad7eb0be6e902502b6ce114 --- /dev/null +++ b/marked/K/T-REC-K.34-202012-I_PDF-E/raw.md @@ -0,0 +1,721 @@ + + +International Telecommunication Union + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.34** + +(12/2020) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +# --- **Classification of electromagnetic environmental conditions for telecommunication equipment – Basic EMC Recommendation** + +Recommendation ITU-T K.34 + +![ITU logo](6ed175c791b5e156d9c98a8dbcc3318c_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with a white grid pattern, overlaid by a stylized 'ITU' text in blue. + +ITU logo + + + +## Recommendation ITU-T K.34 + +## Classification of electromagnetic environmental conditions for telecommunication equipment – Basic EMC Recommendation + +## Summary + +Recommendation ITU-T K.34 defines electromagnetic environmental classes for telecommunication equipment covering all relevant electromagnetic environmental parameters. This Recommendation applies to telecommunication equipment installed in telecommunication centres, outdoor locations and customer premises. This is a basic EMC Recommendation for telecommunications. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.34 | 1996-05-08 | 5 | 11.1002/1000/3345 | +| 2.0 | ITU-T K.34 | 2000-02-25 | 5 | 11.1002/1000/4906 | +| 3.0 | ITU-T K.34 | 2003-07-29 | 5 | 11.1002/1000/6494 | +| 4.0 | ITU-T K.34 | 2020-12-14 | 5 | 11.1002/1000/14566 | + +## Keywords + +Customer premises, EMC, environmental conditions, outdoor locations, telecommunication, telecommunication centres. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2021 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 2 | +| 4 Abbreviations and acronyms ..... | 3 | +| 5 Conventions ..... | 4 | +| 6 Electromagnetic environmental parameters ..... | 4 | +| 6.1 Electrostatic voltage ..... | 4 | +| 6.2 Electrical fast transient/burst (EFT/B)..... | 5 | +| 6.3 Conducted radio-frequency voltages..... | 5 | +| 6.4 Radio-frequency fields ..... | 5 | +| 6.5 d.c. voltages..... | 5 | +| 6.6 16 2/3 Hz voltages..... | 5 | +| 6.7 50 Hz/60 Hz voltages ..... | 6 | +| 6.8 Audio frequency voltages..... | 6 | +| 6.9 Surges ..... | 6 | +| 6.10 Voltage variation ..... | 6 | +| 6.11 Voltage fluctuation ..... | 6 | +| 6.12 Voltage interruption..... | 6 | +| 6.13 Audio frequency magnetic fields..... | 6 | +| 6.14 Lightning electromagnetic pulse ..... | 6 | +| 6.15 Low frequency repetitive impulses ..... | 6 | +| 7 Characteristics of environments ..... | 7 | +| 7.1 Telecommunication centres (common features for class 1 and class 2) ..... | 7 | +| 7.2 Class 3 – Outdoor locations..... | 8 | +| 7.3 Class 4 – Customer premises..... | 8 | +| 8 Characteristic severities of the environmental parameters ..... | 9 | +| Bibliography..... | 17 | + +## Introduction + +This Recommendation is a compilation of data concerning electromagnetic environmental conditions. + +The phenomena covered by this Recommendation are: + +- electrostatic discharges (ESD); +- electrical fast transients/bursts (EFT/B); +- conducted radio-frequency disturbances; +- radiated radio-frequency disturbances; +- d.c. voltages; +- 16 2/3 Hz voltages; +- 50 Hz/60 Hz voltages; +- audio frequency voltages; +- surges; +- voltage variations; +- voltage fluctuations; +- voltage interruptions; +- audio frequency magnetic fields; +- lightning electromagnetic pulses; +- low frequency repetitive impulses. + +The data included in this Recommendation are based on calculation, analysis and experience, supported by comprehensive environmental surveys where such surveys exist. + +Certain assumptions on the installation practice are necessary when characterizing the electromagnetic environment. If these assumptions are not satisfied in a particular case, the environmental characteristic may not apply. + +Each environment is characterized in two ways: + +- by a short verbal description; +- by a quantitative statement of the characteristic severities of the phenomena. + +The appropriate EMC requirements for telecommunication equipment should be based on the severity of the electromagnetic environment. The EMC requirements ensure that the equipment has a sufficient intrinsic immunity to enable it to operate as intended in its environment. It is emphasized that the characteristic severity of a phenomenon or parameter does not automatically indicate the test level used in immunity testing. Other considerations, e.g., priority of service of the equipment in question and technical and economic circumstances should also be taken into account when selecting the test level of those given in basic standards on test methods. + +This Recommendation is a basic EMC Recommendation for telecommunications. + +## Recommendation ITU-T K.34 + +# Classification of electromagnetic environmental conditions for telecommunication equipment – Basic EMC Recommendation + +# 1 Scope + +This Recommendation defines classification of the electromagnetic environmental conditions encountered where telecommunication equipment is installed. + +This Recommendation applies to telecommunication equipment installed in telecommunication centres, outdoor locations and customer premises. It does not make references to equipment dependent details. + +Telecommunication equipment intended for installations in industrial environment, power station and sub-station environments and in railways environment are not covered by this Recommendation because they are already covered by specific EMC standards, e.g., [b-IEC 61000-6-5], [b-IEC 62236-4] and [b-IEC 61000-6-2]. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.18] Recommendation ITU-T K.18 (1988), *Calculation of voltage induced into telecommunication lines from radio station broadcasts and methods of reducing interference*. +- [ITU-T K.23] Recommendation ITU-T K.23 (1988), *Types of induced noise and description of noise voltage parameters for ISDN basic user networks*. +- [ITU-T K.27] Recommendation ITU-T K.27 (2015), *Bonding configurations and earthing inside a telecommunication building*. +- [ITU-T K.68] Recommendation ITU-T K.68 (2006), *Operator responsibilities in the management of electromagnetic interference by power systems on telecommunication systems*. + +# 3 Definitions + +The following definitions apply only in the context of this Recommendation, except where the reference to the International Electrotechnical Vocabulary [IEC 60050-161] is given adjacent to the subclause title. + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 burst** [b-IEC 60050-161], (161-02-07): A sequence of a limited number of distinct pulses or an oscillation of limited duration. + +**3.1.2 commercial, public and light-industrial location** [b-IEC 61000-2-5]: Location which exists as areas of the city centre, offices, public transport systems (road/train/underground), and + +modern business centres containing a concentration of office automation equipment (PCs, fax machines, photocopiers, telephones, etc.), and characterized by the fact that equipment is directly connected to a low-voltage public mains network or connected to a dedicated DC source which is intended to interface between the equipment and the low-voltage mains network. + +Examples of commercial, public or light-industrial locations are: + +- retail outlets, for example shops, supermarkets; +- business premises, for example offices, banks, hotels, data centres; +- areas of public entertainment, for example cinemas, public bars, dance halls; +- places of worship, for example temples, churches, mosques, synagogues; +- petrol stations, car parks, amusement and sports centres; +- general public locations, for example park, amusement facilities, public offices; +- hospitals, educational institutions, for example schools, universities, colleges; +- public traffic area, railway stations, and public areas of an airport; +- light-industrial locations, for example workshops, laboratories, service centres. + +**3.1.3 continuous disturbance** [b-IEC 60050-161], (161-02-11): Electromagnetic disturbance the effect of which on a particular device or equipment cannot be resolved into a succession of distinct effects. + +**3.1.4 immunity (to a disturbance)** [b-IEC 60050-161], (161-01-20): The ability of a device, equipment or system to perform without degradation in the presence of an electromagnetic disturbance. + +**3.1.5 pulse** [b-IEC 60050-161], (161-02-02): An abrupt variation of short duration of a physical quantity followed by a rapid return to the initial value. + +**3.1.6 residential location** [b-IEC 61000-2-5]: Location which exists as an area of land designated for the construction of domestic dwellings, and is characterized by the fact that equipment is directly connected to a low-voltage public mains network or connected to a dedicated DC source which is intended to interface between the equipment and the low-voltage mains network. + +Examples of residential locations are houses, apartments, and farm buildings used for living. + +**3.1.7 rise time (of a pulse)** [b-IEC 60050-161], (161-02-05): The interval of time between the instants at which the instantaneous value of a pulse first reaches a specified lower value and then a specified upper value. + +NOTE – Unless otherwise specified, the lower and upper values are fixed at 10% and 90% of the pulse magnitude. + +**3.1.8 transient (adjective or noun)** [b-IEC 60050-161], (161-02-01): Pertaining to or designating a phenomenon or a quantity which varies between two consecutive steady states during a time interval short compared with the time scale of interest. + +### **3.2 Terms defined in this Recommendation** + +This Recommendation defines the following terms: + +**3.2.1 audio frequencies (AF)**: The frequency range from 50 Hz to 20 kHz. + +**3.2.2 characteristic severity**: The characteristic severity for a certain detail parameter in an environmental class states a severity which has only a low probability, generally less than 1%, of being exceeded. The term relates to duration, rate of occurrence or location. It applies to requirements on the environment and to immunity requirements. In [b-IEC/TR 61000-2-5], the term "disturbance degree" is used as the quantitative characterization of the environmental parameters. + +**3.2.3 customer premises:** Physical location in the residential, commercial, public and light-industrial locations where telecommunication equipment is installed or used. In this environment the electromagnetic disturbance protection and earthing and bonding conditions might be uncontrolled. The electromagnetic environmental conditions for customer premises are described in this Recommendation. + +**3.2.4 environment; environmental conditions:** The electromagnetic conditions external to the equipment, to which it is subjected for a certain time. The environmental conditions comprise a combination of single environmental parameters and their severities. + +**3.2.5 environmental class:** A representation of the environment on locations with similar properties. They are specified and standardized to provide an operational frame of reference for: + +- requirements on the environment; +- immunity requirements. + +The class is described using an envelope of environmental conditions expressed in terms of a number of environmental parameters and their characteristic severities or other characteristics. The environmental parameters specified for the class are limited to those which may affect equipment performance. + +**3.2.6 environmental parameters:** The environmental parameters present one or more properties of the electromagnetic environment. + +**3.2.7 radio frequencies (RF):** The frequency range above 9 kHz. + +**3.2.8 shielding effectiveness:** For a given external source, the ratio (usually expressed in dB) of electric or magnetic field strength at a point before and after the placement of the shield in question. + +**3.2.9 telecommunication centre:** Physical location hosting telecommunication equipment which is managed and operated exclusively by the telecom operator and other business entities. This definition includes the data centres. This environment is dedicated to telecommunication network equipment and is better controlled in terms of electromagnetic disturbance protection and earthing and bonding. The electromagnetic environmental conditions for telecommunication centres are described in this Recommendation. + +## 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|------------------------------------------------| +| a.c. | alternating current | +| AF | Audio Frequency | +| d.c. | direct current | +| EFT/B | Electrical Fast Transient/Burst | +| EMC | Electromagnetic Compatibility | +| ESD | Electrostatic Discharge | +| HV | High Voltage | +| IEC | International Electrotechnical Commission | +| ISM | Industrial, Scientific and Medical (equipment) | +| ITE | Information Technology Equipment | +| RF | Radio Frequency | + +## 5 Conventions + +None. + +# 6 Electromagnetic environmental parameters + +### 6.1 Electrostatic voltage + +Persons walking on the floor or moving otherwise or handling electrostatically charged objects are charged to an electrostatic voltage resulting as an electrostatic discharge (ESD) which may cause malfunction or even damage of equipment. + +The discharge may normally occur when the equipment is operated manually, or during maintenance or repair. The discharge may take place from the fingertips or via metallic tools to all accessible parts of the equipment. + +The risk is particularly high in locations with synthetic flooring materials or when the relative humidity is low, e.g., due to low outdoor temperature. The severity of the discharge depends on the clothing materials and the insulating properties of the soles of the shoes worn by the operator. The risk is almost eliminated if the relative humidity is above 50%. + +Figures 1 and 2 give guidance on the levels that may be observed dependent on the materials used and the environment in which the system is operating. This information has been used in the classification. + +![Figure 1: A line graph showing the maximum values of electrostatic voltages (kV) on the y-axis (0 to 16) versus relative humidity (%) on the x-axis (0 to 100). Three lines represent different materials: Synthetic, Wool, and Antistatic. The Synthetic line starts at 15 kV at 5% RH and decreases to about 1.5 kV at 100% RH. The Wool line starts at 5 kV at 5% RH and decreases to about 0.5 kV at 80% RH. The Antistatic line starts at 4 kV at 5% RH and decreases to about 0.5 kV at 70% RH. Vertical dashed lines are drawn at 5% RH and 35% RH.](df476ed6ad0bb890c67aa63e7647d071_img.jpg) + +| Relative humidity (%) | Synthetic (kV) | Wool (kV) | Antistatic (kV) | +|-----------------------|----------------|-----------|-----------------| +| 5 | 15 | 5 | 4 | +| 10 | 14 | 4.5 | 3.5 | +| 20 | 12.5 | 3.5 | 2.5 | +| 30 | 11 | 2.5 | 1.5 | +| 35 | 10 | 2 | 1 | +| 40 | 9 | 1.5 | 0.5 | +| 50 | 7.5 | 1 | 0.5 | +| 60 | 6 | 0.5 | 0.5 | +| 70 | 4.5 | 0.5 | 0.5 | +| 80 | 3 | 0.5 | 0.5 | +| 90 | 1.5 | 0.5 | 0.5 | +| 100 | 1.5 | 0.5 | 0.5 | + +Figure 1: A line graph showing the maximum values of electrostatic voltages (kV) on the y-axis (0 to 16) versus relative humidity (%) on the x-axis (0 to 100). Three lines represent different materials: Synthetic, Wool, and Antistatic. The Synthetic line starts at 15 kV at 5% RH and decreases to about 1.5 kV at 100% RH. The Wool line starts at 5 kV at 5% RH and decreases to about 0.5 kV at 80% RH. The Antistatic line starts at 4 kV at 5% RH and decreases to about 0.5 kV at 70% RH. Vertical dashed lines are drawn at 5% RH and 35% RH. + +**Figure 1 – Maximum values of electrostatic voltages to which operators may be charged while in contact with the materials in the absence of any electrostatic protection measures** + +![Figure 2: A line graph showing the maximum value of electrostatic voltage (kV) versus relative humidity (%) for operators in a telecommunication central office. The graph compares 'Run' and 'Walk' activities for two types of shoes: 'Ordinary shoes' (open circles and squares) and 'Antistatic shoes' (filled circles and squares) on a 'Linoleum floor'. The voltage decreases as relative humidity increases. Ordinary shoes show higher voltages than antistatic shoes. Running generates higher voltages than walking.](d48475a25698b1c0592e4cfe07138f2a_img.jpg) + +| Relative humidity (%) | Ordinary shoes (Run) [kV] | Ordinary shoes (Walk) [kV] | Antistatic shoes (Run) [kV] | Antistatic shoes (Walk) [kV] | +|-----------------------|---------------------------|----------------------------|-----------------------------|------------------------------| +| 30 | 4.8 | 2.8 | 1.8 | 0.8 | +| 50 | 5.2 | 1.8 | 1.2 | 0.5 | +| 70 | 3.8 | 1.8 | 0.8 | 0.2 | + +Figure 2: A line graph showing the maximum value of electrostatic voltage (kV) versus relative humidity (%) for operators in a telecommunication central office. The graph compares 'Run' and 'Walk' activities for two types of shoes: 'Ordinary shoes' (open circles and squares) and 'Antistatic shoes' (filled circles and squares) on a 'Linoleum floor'. The voltage decreases as relative humidity increases. Ordinary shoes show higher voltages than antistatic shoes. Running generates higher voltages than walking. + +**Figure 2 – Maximum value of electrostatic voltage to which operators may be charged in telecommunication central office** + +### 6.2 Electrical fast transient/burst (EFT/B) + +Breaking of currents in a.c. and d.c. power supplies results in intermittent arcing across the contact. The phenomenon is repetitious and continues until the energy stored in the circuit has been dissipated. A sequence of voltage spikes is generated on the leads. These transients propagate on the line in question and couple to adjacent signal and power lines. + +### 6.3 Conducted radio-frequency voltages + +Different types of radio transmitters and switch mode power supplies induce common and differential mode voltages to power and signal lines. [ITU-T K.18] and [ITU-T K.23] contain more information on this parameter. + +### 6.4 Radio-frequency fields + +Telecommunication equipment is directly exposed to fields of broadcasting, amateur and mobile radio transmitters. Particularly the modern cellular mobile and personal communication service systems operating at high frequencies may couple effectively to printed circuit board level and not only to long lines. + +### 6.5 d.c. voltages + +d.c. voltages apply to signal lines entering the building. Telecommunication equipment may be exposed to high d.c. voltages because of the use of cable fault location equipment. + +d.c. power plants for traction systems causing d.c. potential differences on telecommunication lines are not taken into account. Also induced voltages from geomagnetic activity are not included. + +### 6.6 16 2/3 Hz voltages + +Telecommunication equipment connected to signal lines entering the building may be exposed to common mode 16 2/3 Hz voltages induced to signal lines entering the building in countries where electrical traction systems use this frequency. + +### **6.7 50 Hz/60 Hz voltages** + +Telecommunication equipment connected to signal lines entering the building may be exposed to common mode mains frequency voltages caused by earth faults of high voltage power lines via induction or earth potential rise. 50 Hz/60 Hz electrical traction systems may as well cause exposure to common mode induced voltages. Direct contact to the low voltage mains may cause both common mode and differential mode exposure. + +### **6.8 Audio frequency voltages** + +Telecommunication equipment connected to signal lines entering the building may be exposed to 50 Hz-20 kHz voltages induced to the lines by normal use of neighbouring high voltage power lines and electric traction lines. Non-linear loads on mains may cause audio frequency voltage exposure also via signal lines remaining within the building. Ripple voltages from rectifiers are superimposed on the voltage in d.c. power supplies and contribute to the parameter. + +### **6.9 Surges** + +Telecommunication equipment connected to signal lines entering the building may be exposed to surges coupled into the lines from lightning discharges. Voltage and current surges caused by lightning may enter the equipment also via the a.c. mains. Lightning discharges hitting telecommunication stations, or closely located antenna towers, may expose equipment connected to signal lines remaining within the building via induction or earth potential rise. + +### **6.10 Voltage variation** + +The a.c. or d.c. power supply voltage may vary within certain limits due to varying loads and adjustments of the voltage made to cope with the demand for energy in busy hours. Only the long term variations of the average voltage are included. + +### **6.11 Voltage fluctuation** + +Abrupt changes of loading may cause short term voltage drops and over-voltages of the a.c. or d.c. power supply voltage. + +### **6.12 Voltage interruption** + +Faults in power supply systems may cause intermittent conditions of zero instantaneous voltage of short durations. + +### **6.13 Audio frequency magnetic fields** + +Telecommunication equipment may be exposed to magnetic fields in the frequency band 50 Hz-20 kHz caused by currents at mains frequency and their harmonics in electrical power installations: the distribution network, transformers, motors, power drive and uninterruptible power systems. Fields from audio-frequency inductive wire loops also contribute to these magnetic fields. + +### **6.14 Lightning electromagnetic pulse** + +Telecommunication equipment in the vicinity of a lightning flash may be exposed to magnetic field pulses generated by lightning discharges. + +### **6.15 Low frequency repetitive impulses** + +Telecommunication equipment connected to signal lines entering a building may be exposed to common mode voltages coupled onto lines from long electric fences. The induced disturbance can be characterized in terms of a repetitive impulse (one per second) with a well-damped oscillatory nature. Shorter fences which are not installed properly may also cause this type of interference. + +# 7 Characteristics of environments + +### 7.1 Telecommunication centres (common features for class 1 and class 2) + +The internal electrical power distribution can be up to 400 V d.c. (this includes the 48 V d.c. nominal) and a 230 V/400 V, 127 V/220 V or 100 V a.c. nominal 50 Hz or 60 Hz. It is assumed that switching of loads on the d.c. supply seldom occurs and, therefore, has not been taken into account. Battery back-up is available on d.c. power distributions. + +It is assumed that there is no separation between d.c. power cables and signal cables, while internal a.c. power cables are kept separate at some distance to d.c. power cables and signal cables in order to reduce mutual coupling. Normal practice is to use grounded, metallic cable supports. [ITU-T K.68] provides guidance to reduce coupling between telecommunication systems/lines and power systems/lines. + +Cables from telecommunication centres to customer's premises are assumed to be unshielded. + +A dedicated earthing and bonding network is implemented according to [ITU-T K.27]. Also, the a.c. power distribution inside the building is in accordance with the requirements of this reference. + +Some ESD preventive measures are either incorporated in the building installation (e.g., charge dissipating floors or control of the relative humidity) or through guidelines for handling and operation of the equipment (e.g., use of wrist-straps, charge dissipating shoes). + +Some distance to high power broadcast transmitters is assumed. In cases where radiocommunication transmitters are present at the premises, it is assumed that special precautions are taken in order to prevent exposure of the emitted field. Use of mobile radio equipment is assumed in telecommunication centres. The telecommunication operator cannot control the external radio-frequency environment. + +#### 7.1.1 Class 1 – Major telecommunication centres + +This environmental class applies to major telecommunication centres in dedicated, separate buildings or parts of buildings which are controlled by the network operator. These would typically be located in urban areas. + +The telecommunication centre has its own electricity power transformed from the public distribution network. The a.c. power distribution inside the building is of the type TN-S, TT or IT. + +External signal lines may be of any type, size or length, normally entering via underground routes. Risk of coupling to high voltage electricity lines or electric traction lines exists. + +The shielding effectiveness from the building structure may give a frequency-dependent attenuation of about 10 dB provided that the structural reinforcement elements of the building are adequately bonded together to form an integral mesh. + +#### 7.1.2 Class 2 – Minor telecommunication centres + +This environmental class applies to minor telecommunication centres in dedicated, separate buildings or parts of buildings which are controlled by the network operator. These would typically be located in rural areas serving the local community and may often be unattended. + +The telecommunication centre may draw its electrical power from the public distribution network either via a dedicated transformer or a transformer shared with the local community. The a.c. power distribution inside the building may be of the type TN-S, TN-C, TT or IT. + +External signal lines may be overhead cables of considerable length. There is a high risk of coupling to high voltage electricity lines or electric traction lines. + +No shielding effectiveness from the building structure can be assumed. + +### 7.2 Class 3 – Outdoor locations + +This environmental class applies to an unattended telecommunications site such as street cabinets, telephone boxes, repeaters and amplifiers on trunk cables, concentrators and cable distribution boxes and to equipment installed on poles or towers or on roofs or external sides of buildings. + +This environmental class may apply also to equipment buried below ground level. Repeaters of submarine cables are not covered by this class. + +External signal lines may be of any type, size or length. There is a high risk of coupling to high voltage electricity lines or electric traction lines. Remote power supplies on signal lines are considered as being intrinsic to the systems and are not considered as being environmental parameters. + +Remote repeaters in rural areas are equipped with overvoltage protection devices. A local ground electrode may not be present in all cases. Other outdoor locations may not be protected, and an external lightning protection system is not assumed. + +The distance to electricity distribution transformers may be small and the mains-related magnetic field exposure may be high. + +The outdoor locations are considered as being low risk areas in terms of electrostatic charges. + +Some distance to high power broadcasting transmitters is assumed. However, amateur transmitters may be closer, and mobile and portable radio transmitters may come very close. + +The installation is enclosed in some housing or cabinet for weather protection purposes. The enclosure is not assumed to shield against electromagnetic fields. + +### 7.3 Class 4 – Customer premises + +This class encompasses the residential, commercial and light industrial environments. An attempt has been made to fit the "disturbance degrees" specified by the [IEC 61000-2-5] onto the tables of clause 8 where the electromagnetic environmental classes are quantitatively specified. The highest disturbance degree is given in the table instead the lower values, if any, are given in Notes below the tables. + +#### 7.3.1 Attributes of customer premises + +#### Media + +##### Radiated + +- No amateur radio closer than 100 m. +- No CB radio closer than 20 m. +- No broadcast transmitter closer than 1 km. +- No cellular communication systems with remote base station closer than 200 m (e.g., GSM, LTE etc.). +- No aviation radar closer than 5 km. +- High concentration of ITE. +- Possible proximity to low power ISM. +- Possible presence of medical therapy equipment. +- Possible presence of audio/hearing aid systems. + +###### a.c. power + +- Relatively high network impedance. +- Cables or overhead lines. +- High harmonic levels. + +- Roof-top mounted equipment. + +###### **d.c. power** + +- Not applicable (no presence of extended d.c. power cables). + +#### **Signal/control** + +- Overhead telecom cables or lines. +- Cables or short overhead spans. +- Close coupling between signal systems and switched power systems. +- Significant lightning exposure. +- Control lines are usually short, less than 10 m. + +#### **Reference** + +- Abundant metallic structures which may or may not be bonded, earthed or grounded. +- Frequent interfaces of power and telecom (including local) systems. +- Local ground can be absent, or present high impedance. +- Multiple local grounds might not be coordinated. + +#### **Additional notes** + +- Interfaces with customer systems. +- HV lines may be routed over buildings. + +# **8 Characteristic severities of the environmental parameters** + +In Tables 1 to 5, the characteristic severities and other characteristics of the relevant environmental parameters are stated for each environmental class for telecommunication equipment. + +It is often not feasible to model the disturbances/parameters in every detail. For instance, the temporal evolution of transients is much too complex to be described realistically. In such cases, simplified models are used which select the characteristic details as appropriate to the standardized test pulses. This approach presumes that the test pulses do emphasize the crucial features. + +In the case of continuous disturbances, the postulated frequency dependence and modulation mode are gross simplifications of reality. A frequency analysis will show that the disturbances are confined within narrow frequency bands separated by "silent" intervals. This complicated (and time-dependent) pattern is replaced by a smooth frequency variation using few levels of amplitude. + +The environmental parameters are arranged in tables according to the coupling path. Five coupling paths are included: + +- 1) **Signal lines entering the building**, which include all telecommunications lines of the extended networks where metallic conductors are used. +- 2) **Signal lines remaining within the building**, which include all signal lines in the local installation using metallic conductors. They are of relatively short lengths, and are confined to the local premises. +- 3) **a.c. power mains** is the low voltage distribution network. +- 4) **d.c. power distribution** is the local power distribution system. This does not include d.c. supplies integrated in the equipment. +- 5) **Enclosure**, which includes the coupling of electromagnetic fields to the internal wiring of the equipment, and the discharge of static electricity. + +**Table 1 – Signal lines entering the building** + +| Coupling path | Environmental parameter | | Class 1 major telecom centres | Class 2 minor telecom centres | Class 3 outdoor locations | Class 4 customer premises | +|------------------------------------|--------------------------------------------------------------|--------------------------------------------------------------------------|----------------------------------------|---------------------------------------------------------------------------------------------------------------------|----------------------------------------|--------------------------------| +| Signal lines entering the building | DC common mode voltage (Note 1) | Ampl. V
Impedance M $\Omega$ | 500
> 1 | | | | +| | 16 2/3 Hz common mode voltage (Note 2) | Ampl. V (rms)
Impedance $\Omega$ | 20
100 | 50
100 | | | +| | 50/60 Hz differential mode voltage (Note 3) | Ampl. V (rms)
Impedance $\Omega$
Duration min | 230/100
10 to 600
about 10 | | | | +| | 50/60 Hz common mode voltage | Ampl. V (rms)
Impedance $\Omega$
Duration s | (Note 3) | 2000; 1500; 1000; 650; 430
100 to 600
$\leq 0.1$ ; 0.1 to 0.2; 0.2 to 0.35; 0.35 to 0.5; 0.5 to 1
(Note 5) | | | +| | Audio freq. common mode voltage | Frequency kHz
Ampl. V (rms)
Impedance $\Omega$ | 0.05-1-20
20-0.5-0.5
100 | 0.05-1-20
30-0.75-0.75
100 | 0.05-1-20
30-0.75-0.75
300 | | +| | Low freq. repetitive impulses | Frequency kHz
Impulses/second
Ampl. V (peak) | 2 (Note 6)
1
75 | | | | +| | Amplitude modulated radio freq. common mode voltage (Note 4) | Freq. MHz
Ampl. V (rms) | 0.009-10
1 | 0.009-10
3 | | 0.009-0.15
3 | +| | | Freq. MHz
Ampl. V (rms) | 10-100
1-0.1
(Note 7) | 10-100
3-0.3
(Note 7) | | | +| | | Freq. MHz
Ampl. V (rms) | | | | 0.15-10
10 | +| | | Freq. MHz
Ampl. V (rms) | | | | 10-30
10-3.3
(Note 7) | +| | | Freq. MHz
Ampl. V (rms) | | | | 30-150
3.3-0.66
(Note 7) | +| | Common mode EFT/Bursts | Ampl. V (peak)
Events/week
Rise time $\mu$ s
Impedance $\Omega$ | 250
several
1 to 100
40 to 80 | | 500
several
1 to 100
40 to 80 | 1000
several
5
50 | + +**Table 1 – Signal lines entering the building** + +| Coupling path | Environmental parameter | | Class 1 major telecom centres | Class 2 minor telecom centres | Class 3 outdoor locations | Class 4 customer premises | +|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------|----------------------------------------------------------------------------------------------------------|----------------------------------------------------------|---------------------------------------------------------------------|------------------------------------------------------------------|---------------------------------------------------------------------| +| | Common mode surge | Ampl. V (peak)
Rise time $\mu\text{s}$
Duration $\mu\text{s}$
Events/year
Impedance $\Omega$ | 300; 1000
1 to 1000
$< 3000$
6; 0.5
20 to 40 | 300; 1000; 3000
1 to 1000
$< 3000$
6; 0.5; 0.2
20 to 40 | 300; 1000; 3000
1 to 1000
$< 3000$
30; 3; 1
20 to 40 | 500; 1000
10; 1
1000; 50
Multiple
20 to 300;
1 to 10 | +| NOTE 1 – 1 M $\Omega$ source impedance included in order to take into account, e.g., cable fault location equipment.
NOTE 2 – Only applicable in countries where 16 2/3 Hz electrical traction systems are in use.
NOTE 3 – For Major Telecom Centres (Class 1), 50 Hz/60 Hz common mode voltage due to earth faults in nearby high voltage electricity systems is not taken into account. The probability of this phenomenon occurring is extremely low.
NOTE 4 – All values given for the amplitudes with respect to radio frequency are the maximum values for common mode voltage, measured with a frequency analysis instrument with narrow frequency bandwidth. As the primary coupling occurs in the last few metres of the line, advantage is taken of the shielding effects of the building (e.g., metallic framework) of the Major Telecom Centre (Class 1).
NOTE 5 – The limits are based on [ITU-T K.68]. Protective measures are assumed on lines where these limits would otherwise be exceeded. In Japan, 650 V for $t \leq 0.06$ s; 430 V for $0.06$ s $< t \leq 0.1$ s; 300 V for $0.1$ s $< t \leq 1.0$ s apply.
NOTE 6 – Damped oscillatory waveform.
NOTE 7 – The level is inversely proportional to the frequency above 10 MHz (Level V = (level @10 MHz $\times$ 10/Frequency in MHz)). | | | | | | | + +**Table 2 – Signal lines remaining within the building** + +| Coupling path | Environmental parameter | | Class 1 major telecom centres | Class 2 Minor telecom centres | Class 3 outdoor locations | Class 4 customer premises | +|--------------------------------------------|---------------------------------------------------------|------------------------------------------------------|--------------------------------|-------------------------------|---------------------------|--------------------------------| +| Signal lines remaining within the building | Audio freq. common mode voltage | Frequency kHz
Ampl. V (rms)
Impedance $\Omega$ | 0.05-1-20
20-0.5-0.5
100 | | Not applicable | 0.05-1-20
10-0.5-0.5
300 | +| | Amplitude modulated radio frequency common mode voltage | Freq. MHz
Ampl. V (rms) | 0.15-10
1 | 0.15-10
3 | Not applicable | 0.01-0.15
3 | +| | | Freq. MHz
Ampl. V (rms) | 10-100
1-0.1
(Note) | 10-100
3-0.3
(Note) | | | +| | | Freq. MHz
Ampl. V (rms) | | | | 0.15-10
10 | +| | | Freq. MHz
Ampl. V (rms) | | | | 10-30
10-3.3
(Note) | + +**Table 2 – Signal lines remaining within the building** + +| Coupling path | Environmental parameter | | Class 1 major telecom centres | Class 2 Minor telecom centres | Class 3 outdoor locations | Class 4 customer premises | +|---------------|-------------------------|--------------------------------------------------------------------------|----------------------------------------|-------------------------------|---------------------------|------------------------------| +| | | Freq. MHz
Ampl. V (rms) | | | | 30-150
3.3-0.66
(Note) | +| | Common mode EFT/Bursts | Ampl. V (peak)
Events/week
Rise time $\mu$ s
Impedance $\Omega$ | 250
several
1 to 100
40 to 80 | | Not applicable | 1000
several
5
50 | + +NOTE – The level is inversely proportional to the frequency above 10 MHz (Level V = (level @10 MHz $\times$ 10/Frequency in MHz). + +**Table 3 – a.c. power ports** + +| Coupling path | Environmental parameter | | Class 1 major telecom centres | Class 2 minor telecom centres | Class 3 outdoor locations | Class 4 customer premises | +|------------------|------------------------------------------------------------------|---------------------------------------------------|-----------------------------------------------------|-------------------------------|---------------------------|-------------------------------------| +| | Voltage variation | Voltage changer % | $\pm 10$ | $+10/-15$ | | $\pm 8$ | +| | Voltage fluctuation | Voltage changer %
Duration ms
Events/day | $-50$ to $-20$ ; $+20$
10 to 1500
100 to 0.01 | | | 10 to 99
$< 3000$
unspecified | +| | Voltage interruption | Duration ms
Events/day | 10; 20; 40; 100 to 700
10; 1; 0.1; 0.05 | | | $< 6000$
unspecified | +| a.c. power mains | Amplitude modulated radio frequency common mode voltage (Note 1) | Freq. MHz
Ampl. V (rms) | 0.009-10
1 | 0.009-10
3 | | 0.009-0.15
3 | +| | | Freq. MHz
Ampl. V (rms) | 10-100
1-0.1
(Note 4) | 10-100
3-0.3
(Note 4) | | | +| | | Freq. MHz
Ampl. V (rms) | | | | 0.15-10
10 | +| | | Freq. MHz
Ampl. V (rms) | | | | 10-150
3-0.2
(Note 4) | +| | Common and differential mode EFT/Bursts | Ampl. V (peak)
Events/day
Rise time $\mu$ s | 1000
1
1 to 100 | | | 2000 (Note 2)
several
5 | + +**Table 3 – a.c. power ports** + +| Coupling path | Environmental parameter | | Class 1 major telecom centres | Class 2 minor telecom centres | Class 3 outdoor locations | Class 4 customer premises | +|-------------------|-------------------------|-----------------------------------------------------------------------------------------------------------|-------------------------------|--------------------------------------------------|---------------------------|----------------------------------------------------------------| +| | Surge line/neutral | Ampl. kV (peak)
Rise time $\mu\text{s}$
Duration $\mu\text{s}$
Events/year | 2
0.5 to 10
< 100
20 | 2; 4
0.5 to 10
< 100
100; 3 | | | +| Surge line/ground | | Ampl. kV (peak)
Rise time $\mu\text{s}$
Duration $\mu\text{s}$
Events/year
Impedance $\Omega$ | (Note 3) | 2; 4
0.5 to 10
< 100
100; 3
10 to 20 | | 1; 4
10; 1
1000; 50
Multiple
20 to 300;
1 to 10 | + +NOTE 1 – All values given for the amplitudes with respect to radio frequency are the maximum values for common mode voltage, measured with a frequency analysis instrument with narrow frequency bandwidth. As the primary coupling occurs in the last few metres of the line, advantage is taken of the shielding effects of the building (e.g., metallic framework) of the Major Telecom Centre (Class 1). + +NOTE 2 – Only specified for certain types of customer premises. + +NOTE 3 – Not applicable because Major Telecom Centres (Class 1) have their own electricity power transformers. + +NOTE 4 – The level is inversely proportional to the frequency above 10 MHz (Level V = (level @10 MHz $\times$ 10/Frequency in MHz)). + +**Table 4 – d.c. power ports** + +| Coupling path | Environmental parameter | | Class 1 major telecom centres | Class 2 minor telecom centres | Class 3 outdoor locations | Class 4 customer premises | +|-------------------------|-----------------------------------------------------|----------------------------------------------------------|---------------------------------------|-------------------------------|-----------------------------|---------------------------| +| | Voltage variation | Voltage V | 40.5/57 | | | | +| d.c. power distribution | Voltage fluctuation and interruption | Voltage V
Duration ms
Events/year | 0 to 40.5; 57 to 60
< 50
3 | | | Not applicable | +| | Audio freq. differential mode voltage | Frequency kHz
Ampl. mV (rms) | 0.025-0.3-1-20-150
50-50-7-7/50-50 | | | | +| | Amplitude modulated radio freq. common mode voltage | Freq. MHz
Ampl. V (rms) | 0.15-10
1 | 0.15-10
3 | 0.15-10
1 | | +| | | Freq. MHz
Ampl. V (rms) | 10-100
1-0.1
(Note 3) | 10-100
3-0.3
(Note 3) | 10-100
1-0.1
(Note 3) | | +| | Common and differential mode EFT/Bursts | Ampl. V (peak)
Events/week
Rise time $\mu\text{s}$ | 250
several
1 to 100 | | | | + +**Table 4 – d.c. power ports** + +| Coupling path | Environmental parameter | | Class 1 major telecom centres | Class 2 minor telecom centres | Class 3 outdoor locations | Class 4 customer premises | +|---------------|---------------------------------------------|------------------------------------------------------------------------------------|-------------------------------|-------------------------------|---------------------------|---------------------------| +| | Common and differential mode surge (Note 1) | Ampl. V (peak)
Rise time $\mu\text{s}$
Duration $\mu\text{s}$
Events/year | 200
5
50
3 | | Not applicable | | + +NOTE 1 – From fuse blowing. + +NOTE 2 – Class 3 does not apply to remote d.c. supplies via the signal lines. In such cases, the appropriate classification for "Signal lines entering the building" is to be used. + +NOTE 3 – The logarithm of the level linearly decreases with the logarithm of the frequency in the range 10 to 100 MHz. + +**Table 5 – Enclosure** + +| Coupling path | Environmental parameter | | Class 1 major telecom centres | Class 2 minor telecom centres | Class 3 outdoor locations | Class 4 customer premises | +|---------------|-----------------------------------------------------------|---------------------------------|-------------------------------|-------------------------------|----------------------------------|------------------------------------| +| Enclosure | Audio freq. magnetic field | Frequency Hz
Ampl. A/m (rms) | 50 to 20 000
10 to 0.025 | 50 to 20 000
3 to 0.008 | 50 to 20 000
10 to 0.025 | $16^{2/3}$ ; 50 to 20k
1; 0.015 | +| | | Frequency Hz
Ampl. A/m (rms) | | | | 50; 100 to 3000
10; 1.8 to 0.6 | +| | Pulse modulated radio freq. electromagnetic field | Freq. GHz
Ampl. V/m (peak) | 1-20
1 | 1-20
3 | 1-20
10 | 1-20
3 | +| | Modulated radio freq. of Amateur radio bands below 30 MHz | Freq. MHz
Ampl. V/m (rms) | | | 0.13-29,7
1
(Note 1) | 0.13-29,7
1
(Note 1) | +| | Modulated radio freq. of CB band 27 MHz | Freq. MHz
Ampl. V/m (rms) | | | 26.560-27.991
0,3
(Note 2) | 26.560-27.991
0,3
(Note 2) | +| | Analogue radio communication services below 30 MHz | Freq. MHz
Ampl. V/m (rms) | 0.150-30
3
(Note 3) | 0.150-30
3
(Note 3) | 0.150-30
3
(Note 3) | 0.150-30
3
(Note 3) | + +**Table 5 – Enclosure** + +| Coupling path | Environmental parameter | | Class 1 major telecom centres | Class 2 minor telecom centres | Class 3 outdoor locations | Class 4 customer premises | +|---------------|---------------------------------------------------------------------|-----------------|-------------------------------|-------------------------------|---------------------------|---------------------------| +| | | | | | | | +| | Analogue radio communication services above 30 MHz | Freq. MHz | 48-853 | 48-853 | 48-853 | 48-853 | +| | | Ampl. V/m (rms) | 3
(Note 4) | 3
(Note 4) | 3
(Note 4) | 3
(Note 4) | +| | Modulated radio communication services (mobile and portable phones) | Freq. MHz | 890-915 | 890-915 | 890-915 | 890-915 | +| | | Ampl. V/m (rms) | 3
(Note 5) | 3
(Note 5) | 3
(Note 5) | 3
(Note 5) | +| | | Freq. MHz | 1710-1784 | 1710-1784 | 1710-1784 | 1710-1784 | +| | | Ampl. V/m (rms) | 3
(Note 6) | 3
(Note 6) | 3
(Note 6) | 3
(Note 6) | +| | | Freq. MHz | | | | 1880-1960 | +| | | Ampl. V/m (rms) | | | | 3
(Note 7) | +| | Modulated radio communication services (base stations) | Freq. MHz | 1900-1980 | 1900-1980 | 1900-1980 | 1900-1980 | +| | | Ampl. V/m (rms) | 3
(Note 8) | 3
(Note 8) | 3
(Note 8) | 3
(Note 8) | +| | | Freq. MHz | 450-7125/24250-27900 | 450-7125/24250-27900 | 450-7125/24250-27900 | 450-7125/24250-27900 | +| | | Ampl. V/m (rms) | 3
(Note 15) | 3
(Note 15) | 3
(Note 15) | 3
(Note 15) | +| | | Freq. MHz | 935-960 | 935-960 | 935-960 | 935-960 | +| | | Ampl. V/m (rms) | 3
(Note 9) | 3
(Note 9) | 3
(Note 9) | 3
(Note 9) | +| | | Freq. MHz | 1805-1880 | 1805-1880 | 1805-1880 | 1805-1880 | +| | | Ampl. V/m (rms) | 3
(Note 10) | 3
(Note 10) | 3
(Note 10) | 3
(Note 10) | +| | | Freq. MHz | | | | 1880-1960 | +| | | Ampl. V/m (rms) | | | | 3
(Note 11) | +| | | Freq. MHz | 1900-2170 | 1900-2170 | 1900-2170 | 1900-2170 | +| | | Ampl. V/m (rms) | 3
(Note 12) | 3
(Note 12) | 3
(Note 12) | 3
(Note 12) | +| | | Freq. MHz | 450-7125 | 450-7125 | 450-7125 | 450-7125 | +| | | Ampl. V/m (rms) | 3
(Note 16) | 3
(Note 16) | 3
(Note 16) | 3
(Note 16) | +| | | Freq. MHz | 24250-27900 | 24250-27900 | 24250-27900 | 24250-27900 | +| | | Ampl. V/m (rms) | 3
(Note 16) | 3
(Note 16) | 3
(Note 16) | 3
(Note 16) | +| | | Freq. MHz | 3 | 3 | 3 | | +| | | Ampl. V/m (rms) | (Note 16) | (Note 16) | (Note 16) | | + +**Table 5 – Enclosure** + +| Coupling path | Environmental parameter | | Class 1 major telecom centres | Class 2 minor telecom centres | Class 3 outdoor locations | Class 4 customer premises | +|---------------|---------------------------------|----------------------------------------------------------------|-------------------------------|-------------------------------|-----------------------------|------------------------------------------| +| | High speed wireless LANs | Freq. GHz
Ampl. V/m (rms) | 2400-2483
3
(Note 13) | 2400-2483
3
(Note 13) | 2400-2483
3
(Note 13) | 2400-2483
3
(Note 13) | +| | | Freq. GHz
Ampl. V/m (rms) | 5150-5875
3
(Note 14) | 5150-5875
3
(Note 14) | 5150-5875
3
(Note 14) | 5150-5875
3
(Note 14) | +| | Electrostatic Voltage | Ampl. kV (peak) | 4
(Note 15) | 4
(Note 15) | 2 | 8
(Note 16) | +| | Lightning electromagnetic pulse | Ampl. A/m (peak)
Rise time µs
Duration µs
Events/year | Not applicable | 500
0.2
100
0.1 | Not applicable | Specified by the slew rate
100 V/m/ns | + +NOTE 1 – Max field at 271 m from the source of 1500 W (ERP), [b-IEC/TR 61000-2-5]. + +NOTE 2 – Max field at 63,2 m from the source of 4 W ERP (AM, FM), [b-IEC/TR 61000-2-5]. + +NOTE 3 – Max field at 1650 m from the source of 500 kW AM broadcasting, [b-IEC/TR 61000-2-5]. + +NOTE 4 – Max field at 1650 m from the source of 500 kW TV UHF, [b-IEC/TR 61000-2-5]. + +NOTE 5 – Max field at 10,5 m from the GSM source of 20 W Mobile, . [b-IEC/TR 61000-2-5]. + +NOTE 6 – Max field at 4,7 m from the DCS1800 source of 4 W, [b-IEC/TR 61000-2-5]. + +NOTE 7 – Max field at 1,2 m from the DECT source of 0,25W, [b-IEC/TR 61000-2-5]. + +NOTE 8 – Max field at 1,2 m from the IMT2000 source of 0,25 W, [b-IEC/TR 61000-2-5]. + +NOTE 9 – Max field at 206 m from the GSM source of 320 W (ERP), [b-IEC/TR 61000-2-5]. + +NOTE 10 – Max field at 163 m from the DCS1800 source of 200 W (ERP), [b-IEC/TR 61000-2-5]. + +NOTE 11 – Max field at 5,7 m from the DECT source of 0,25W (ERP), [b-IEC/TR 61000-2-5]. + +NOTE 12 – Max field at 52 m from the IMT2000 source of 20 W (ERP), [b-IEC/TR 61000-2-5]. + +NOTE 13 – Max field at 5,8 m from the source of 0,1 W (ERP), [b-IEC/TR 61000-2-5]. + +NOTE 14 – Max field at 18 m from the source of 1 W (ERP), [b-IEC/TR 61000-2-5]. + +NOTE 15 – Max field at 0,6 m from the IMT2020 source of 17,95 dBm at antenna port and antenna gain of 2.4 dBi. + +NOTE 16 – Max field at 23 m from the IMT2020 source of 35 dBm at antenna port and antenna gain of 17 dBi, [b-3GPP 38.104]. + +NOTE 17 – If limited electrostatic protection is applied, a higher level of electrostatic may occur. + +NOTE 18 – In higher humidity environments, lower levels of electrostatic may occur. [b-IEC/TR 61000-2-5] specifies 4 kV. + +NOTE 19 – To determine the field strength at other distances from the source reported in this table, in far field condition can use the following dipole formula: + +$$E = k \sqrt{P}/d,$$ + +where: + +- E is the field strength (RMS value) (V/m); +- k is a constant, with a value of 7, for free-space propagation in the far field; +- P is the power (ERP) (W); +- d is the distance from the antenna (m). +- If the ERP of the transmitter is not known, the power provided to the antenna may be used and, in this case, a value of $k = 3$ is typically applicable for mobile radio transmitters. + +# Bibliography + +- [b-IEC 60050-161] IEC 60050-161:1990, *International Electrotechnical Vocabulary (IEV) – Part 161: Electromagnetic Compatibility.* +- [b-IEC/TR 61000-2-5] IEC/TR 61000-2-5:2017, *Electromagnetic compatibility (EMC) – Part 2-5: Environment – Description and classification of electromagnetic environments.* +- [b-IEC 61000-6-2] IEC 61000-6-2:2016, *Electromagnetic compatibility (EMC) – Part 6-2: Generic standards – Immunity standard for industrial environments.* +- [b-IEC 61000-6-5] IEC 61000-6-5:2015, *Electromagnetic compatibility (EMC) – Part 6-5: Generic standards – Immunity for equipment used in power station and substation environment.* +- [b-IEC 62236-4] IEC 62236-4:2018, *Railway applications – Electromagnetic compatibility – Part 4: Emission and immunity of the signalling and telecommunications apparatus.* +- [b-3GPP 38.104] 3GPP 38.104: Release 16, NR; Base Station (BS) radio transmission and reception. +- [b-ANSI C63.12] ANSI C63.12 (1999), *American National Standard for Electromagnetic Compatibility Limits – Recommended Practice.* +- [b-ETSI TR 101 651] ETSI TR 101 651 V1.1.1 (1999), *Electromagnetic compatibility and radio spectrum matters (ERM); Classification of the electromagnetic environment conditions for equipment in telecommunication networks.* + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.35-202012-I_PDF-E/51db757d054ce1ce83c436a3578b56ca_img.jpg b/marked/K/T-REC-K.35-202012-I_PDF-E/51db757d054ce1ce83c436a3578b56ca_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..b1ba63895a04869a6a4185248966c7fc24c4dc75 --- /dev/null +++ b/marked/K/T-REC-K.35-202012-I_PDF-E/51db757d054ce1ce83c436a3578b56ca_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:e17d1d615d37e862ed1a0e7733e4865e268a28ad6a3216783f2ee9ce2c2058b2 +size 85691 diff --git a/marked/K/T-REC-K.35-202012-I_PDF-E/6f341f415ee0f8c724e5d6daeb1e9b4a_img.jpg b/marked/K/T-REC-K.35-202012-I_PDF-E/6f341f415ee0f8c724e5d6daeb1e9b4a_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..55ffeb54d93f5268e5f6a2d29a89873722f6a5bc --- /dev/null +++ b/marked/K/T-REC-K.35-202012-I_PDF-E/6f341f415ee0f8c724e5d6daeb1e9b4a_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:3b4c31f6715696a5c07b5f3dd52ae1ad1f423e1021f4edf71ef45ca9a3c53756 +size 43713 diff --git a/marked/K/T-REC-K.35-202012-I_PDF-E/7efae06af3af43ffe5d4b956a679cf54_img.jpg b/marked/K/T-REC-K.35-202012-I_PDF-E/7efae06af3af43ffe5d4b956a679cf54_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..57d53a92f37a2b2f92b1dcfa2f59493f13f04937 --- /dev/null +++ b/marked/K/T-REC-K.35-202012-I_PDF-E/7efae06af3af43ffe5d4b956a679cf54_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:bd9540b05b26f5dc5189ee312a8243d5368b6cb65bc36b2a676fca324febf4bb +size 65494 diff --git a/marked/K/T-REC-K.35-202012-I_PDF-E/84a1d09fb489061482111515543b60dc_img.jpg b/marked/K/T-REC-K.35-202012-I_PDF-E/84a1d09fb489061482111515543b60dc_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..9002ee68e2b9ebf63d27d39ba8c73bdafb0e6be6 --- /dev/null +++ b/marked/K/T-REC-K.35-202012-I_PDF-E/84a1d09fb489061482111515543b60dc_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:8df701536c25ab8246d2868de3c20c8a4e25168bb52c5eb9078278ab1b5b4fd8 +size 6859 diff --git a/marked/K/T-REC-K.35-202012-I_PDF-E/8fbdfc3d17fb1dae7b2d8f5a287fa9fc_img.jpg b/marked/K/T-REC-K.35-202012-I_PDF-E/8fbdfc3d17fb1dae7b2d8f5a287fa9fc_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..cd54c620dbfd71e2abaa5b8016d6394036bccd38 --- /dev/null +++ b/marked/K/T-REC-K.35-202012-I_PDF-E/8fbdfc3d17fb1dae7b2d8f5a287fa9fc_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:194826558ad432984bdc90adc171a9909c18defa82b3b38339046948a519ddb7 +size 39661 diff --git a/marked/K/T-REC-K.35-202012-I_PDF-E/cfef993dcc8fb513de79eb1f93cf26ae_img.jpg b/marked/K/T-REC-K.35-202012-I_PDF-E/cfef993dcc8fb513de79eb1f93cf26ae_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..f2d4ba2108ed82d0100d72d10ade9dbf1d2e78d0 --- /dev/null +++ b/marked/K/T-REC-K.35-202012-I_PDF-E/cfef993dcc8fb513de79eb1f93cf26ae_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:1931a71876266b987d313d0991e1fae21e4511d8ca10ae2a86cbeefe71ffcb82 +size 153920 diff --git a/marked/K/T-REC-K.35-202012-I_PDF-E/raw.md b/marked/K/T-REC-K.35-202012-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..6bc824a80d82f0f420d68868c5f0d4395a89a87e --- /dev/null +++ b/marked/K/T-REC-K.35-202012-I_PDF-E/raw.md @@ -0,0 +1,574 @@ + + +International Telecommunication Union + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.35** + +(12/2020) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +# --- **Bonding configurations and earthing at remote electronic sites** + +Recommendation ITU-T K.35 + +ITU-T + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a red lightning bolt striking it, symbolizing telecommunications. To the right of the globe, the text "International Telecommunication Union" is written in a blue sans-serif font, with "ITU" in a larger, bold font above it. + +ITU logo + +International +Telecommunication +Union + + + +## Recommendation ITU-T K.35 + +## Bonding configurations and earthing at remote electronic sites + +## Summary + +Bonding configurations, earthing, and the type of power distribution for equipment located at remote electronic sites are proposed, which are intended to promote harmony of installation and equipment configurations while providing for personnel safety and electromagnetic compatibility. + +With the popularization of 5G mobile communication, the number of outdoor communication equipment is increasing rapidly. In order to reduce costs, outdoor electronic equipment cabinets (EECs) substitute outdoor shelters for telecommunication systems. Telecommunication equipment (baseband units (BBUs)), power supply equipment, battery, temperature control equipment, optical transmission equipment and other ancillary equipment can be installed in these outdoor cabinets. + +Recommendation ITU-T K.35 (2018) gives the definition of electronic equipment cabinet (EEC), earthing, bonding, but it is not detailed. For example, the surge protective device (SPD) configuration in the outdoor cabinet, the setting of the earthing terminal (main earthing terminal, optical cable dedicated earthing terminal), and the bonding of the equipment in the cabinet are not specified in detail. It is difficult for users of standards to obtain effective specifications and guidelines. + +China industrial standard YD/T 1537-2015, *Outdoor cabinets for telecommunication system*, had defined EEC as "integrated access outdoor cabinet" and "base station outdoor cabinet" depending on the application situation. This standard provides more information on lightning protection and earthing. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.35 | 1996-05-08 | 5 | 11.1002/1000/3346 | +| 2.0 | ITU-T K.35 | 2018-01-13 | 5 | 11.1002/1000/13443 | +| 3.0 | ITU-T K.35 | 2020-12-14 | 5 | 11.1002/1000/14567 | + +## Keywords + +Bonding, earthing, electronic equipment cabinet (EEC), electronic equipment enclosure (EEE), safety. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2021 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|-----|------------------------------------------------------------------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 3.1 | Terms defined elsewhere ..... | 2 | +| 3.2 | Terms defined in this Recommendation..... | 2 | +| 4 | Abbreviations and acronyms ..... | 3 | +| 5 | Conventions ..... | 3 | +| 6 | Earthing network for electronic equipment enclosures (EEEs)..... | 3 | +| 6.1 | Earthing ring for above ground and below ground EEEs..... | 3 | +| 6.2 | Earthing ring for EEC..... | 3 | +| 6.3 | Concrete-encased earth electrode ..... | 4 | +| 7 | a.c. power distribution ..... | 4 | +| 7.1 | a.c. power line surge protective device ..... | 4 | +| 8 | d.c. power distribution ..... | 6 | +| 9 | Bonding configuration ..... | 6 | +| 9.1 | Main earthing terminal ..... | 6 | +| 9.2 | Interior bonding-bus ..... | 7 | +| 9.3 | Outside-plant cable entrance ..... | 7 | +| 9.4 | Equipment framework ..... | 8 | +| 9.5 | Surge protectors on communication pairs ..... | 8 | +| 9.6 | Metallic walls ..... | 8 | +| | Appendix I – Example of bonding configurations and earthing of EEEs by use of ring bonding-bus ..... | 9 | +| | Appendix II – Example of A.C. power line surge protective device ..... | 10 | +| | Appendix III – Example of Bonding-bus for EEC ..... | 12 | +| | Bibliography..... | 13 | + +## Introduction + +Electronic equipment enclosures remotely located from telecommunication buildings are increasingly being used to contain a variety of telecommunication equipment. Differences such as size, shape and local environmental stresses give rise to the need for electromagnetic compatibility measures that differ from those at telecommunication buildings [ITU-T K.27] or at customer premises [ITU-T K.66]. + +The nomenclature and measures of this Recommendation are intended to promote harmony of installation and equipment configurations while providing for personnel safety and electromagnetic compatibility. + +Although the bonding configurations and earthing measures of this Recommendation contribute to the reduction of electrical surge energy that reaches installed equipment, surge protectors, as described in [ITU-T K.11], may be needed on the conductors of wire-line cables. Furthermore, the equipment must be capable of resisting the residual surges that reach it. Equipment resistibility is described in [ITU-T K.20]. + +## Recommendation ITU-T K.35 + +## Bonding configurations and earthing at remote electronic sites + +## 1 Scope + +This Recommendation covers bonding configurations and earthing for equipment located at remote electronic sites such as switching or transmission huts, cabinets or controlled environmental vaults with only one level, a need for a.c. mains power service and a floor space of about 100 m2 without an antenna tower on the roof of the building as well as nearby; but which are more substantial than small electronic housings, such as carrier repeaters or distribution terminals. Experience in the operation of electronic equipment enclosures shows that the use of a bonding configuration and earthing that are coordinated with equipment capability and with electrical protection devices has the following attributes: + +- promotes personnel safety and reduces fire hazards; +- enables signalling with earth return (functional earthing); +- minimizes service interruptions and equipment damage caused by lightning, exposures to power lines and faults in internal d.c. power supplies; +- minimizes radiated and conducted emissions and susceptibility; +- improves system tolerance to discharge of electrostatic energy. + +Within this framework, this Recommendation: + +- a) is a guide to bonding configurations and earthing of telecommunication equipment in electronic equipment enclosures; +- b) is intended to comply with safety requirements imposed by [IEC 60364 series] or national standardizing bodies on a.c. power installations; +- c) is intended for installation of new electronic equipment enclosures; +- d) treats coordination with electrical protection devices, but does not provide details of protective measures specific to electronic equipment enclosures; +- e) utilizes the shielding contribution of effective elements of the structure and its contents; +- f) addresses the bonding of cable shields; +- g) is intended to facilitate electromagnetic compatibility of telecommunication equipment; +- h) does not include protection against lightning electromagnetic pulses (LEMPs). + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.11] Recommendation ITU-T K.11 (2009), *Principles of protection against overvoltages and overcurrents*. + +- [ITU-T K.20] Recommendation ITU-T K.20 (2019), *Resistibility of telecommunication equipment installed in a telecommunication centre to overvoltages and overcurrents.* +- [ITU-T K.27] Recommendation ITU-T K.27 (2015), *Bonding configurations and earthing inside a telecommunication building.* +- [ITU-T K.66] Recommendation ITU-T K.66 (2011), *Protection of customer premises from overvoltages.* +- [IEC 60364-4-44] IEC 60364-4-44:2007, *Low-voltage electrical installations – Part 4-44: Protection for safety – Protection against voltage disturbances and electromagnetic disturbances.* +- [IEC 60364-5-54] IEC 60364-5-54:2011, *Low-voltage electrical installations – Part 5-54: Selection and erection of electrical equipment – Earthing arrangements and protective conductors.* +- [IEC 60364 series] IEC 60364 series, *Electrical installations of buildings.* +- [IEV 826] IEC 60050-826:2004, *International Electrotechnical Vocabulary (IEV) – Part 826: Electrical installations.* + +## 3 Definitions + +### 3.1 Terms defined elsewhere + +In this Recommendation, definitions with respect to bonding configurations and earthing already introduced by [IEV 826] and [ITU-T K.27] are used to maintain conformity. + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following additional terms for remote electronic sites: + +**3.2.1 above-ground electronic equipment enclosure (AG/EEE):** An electronic equipment enclosure (EEE) that is wholly or partially above ground level. Installed equipment is fully accessible from the interior area. The AG/EEE subcategory includes transportable structures as well as structures partially or fully constructed or assembled on-site. + +**3.2.2 below-ground electronic equipment enclosure (BG/EEE):** An electronic equipment enclosure (EEE) that is completely below ground level except possibly for an entryway, a.c. power service, and environmental control equipment. Installed equipment is fully accessible from the interior area. + +**3.2.3 bonding-bus:** A conductor, or group of conductors, that serves as a common connection between the main earthing terminal and metallic assemblies in the electronic equipment enclosure (EEE). The bonding-bus may also be connected to other busbars or terminals connected to the earthing network or structural steel. + +**3.2.4 electronic equipment cabinet (EEC):** An electronic equipment enclosure (EEE) for which all installed equipment can be fully accessed from the outside without having to enter an interior area. + +**3.2.5 electronic equipment enclosure (EEE):** A structure that provides physical and environmental protection for electronic communication equipment, and that: + +- has only one level; +- has a floor space of no more than about 100 m2; +- has a need for a.c. mains power service. + +**3.2.6 ring bonding-bus:** A bonding-bus whose conductors form a closed, connected ring. + +An example of bonding configurations and earthing of EEEs by use of ring bonding-bus is given in Appendix I. + +## **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|--------|---------------------------------------------| +| AG/EEE | Above-Ground Electronic Equipment Enclosure | +| BBU | Baseband Unit | +| BG/EEE | Below-Ground Electronic Equipment Enclosure | +| CBN | Common Bonding Network | +| EEC | Electronic Equipment Cabinet | +| EEE | Electronic Equipment Enclosure | +| LEMP | Lightning Electromagnetic Pulse | +| SPD | Surge Protective Device | + +## **5 Conventions** + +None. + +## **6 Earthing network for electronic equipment enclosures (EEEs)** + +### **6.1 Earthing ring for above ground and below ground EEEs** + +An above-ground electronic equipment enclosure (AG/EEE) or a below-ground electronic equipment enclosure (BG/EEE) should be provided with a buried exterior earthing ring that satisfies at least the following conditions: + +- the ring should be uninsulated and buried at approximately 0.75 m; +- the ring should encircle the EEE with a spacing, where practical, of about 0.65 m or more from the exterior walls; +- one earthing conductor should connect the ring to the main earthing terminal. + +NOTE – National safety rules may require additional rod electrodes and/or additional connections to the a.c. power service entrance. + +An alternative to the foregoing attachments to the earthing ring is to connect the neutral busbar to a separate earthing network using a separate earthing conductor; the earthing conductor from the main earthing terminal to the earthing ring remains. The main earthing terminal and the neutral busbar are connected within the EEE. This alternative arrangement permits occasional isolation of the earthing ring to monitor its condition without disconnecting the earthing connection on the neutral conductor. + +### **6.2 Earthing ring for EEC** + +The earthing network provides some voltage equalization in the earth near an electronic equipment cabinet (EEC). Whenever feasible, the EEC should be provided with a buried exterior earthing ring that satisfies at least the following conditions: + +- the ring should be uninsulated, buried at a depth of 0.3-0.5 m; +- the ring should encircle the foundation pad of the EEC, or be located below the perimeter of the pad; +- one uninsulated earthing conductor should connect the ring to the main earthing terminal. + +Otherwise, clause 542.2 of [IEC 60364-5-54] should be met. + +NOTE – National safety rules may require additional rod electrodes and/or additional connections to the a.c. power service entrance. + +### **6.3 Concrete-encased earth electrode** + +An EEE often rests on a foundation earth electrode, or is itself constructed of concrete. In this case, the reinforcement or conductor may be used in place of the earthing ring of clauses 6.1 and 6.2. + +## **7 a.c. power distribution** + +It is recommended that the indoor mains installation within a telecommunication building be of type TN-S as specified by the [IEC 60364 series] in order to improve the EMC performance of the telecommunication installation. This requires that there shall be no PEN conductor within the building. Consequently, a three phase network within a telecommunication building is, physically, a five-wire installation (L1, L2, L3, N, PE). + +Depending on the type of outdoor mains distribution network serving a telecommunication building, one of the following requirements shall apply: + +- a) Service by a TN-S section of the outdoor mains distribution network: + - 1) solely the protective conductor (PE) shall be connected to the main earthing terminal (see Figure 1, mode 1). +- b) Service by a TN-C section of the outdoor mains distribution network: + - 1) the PEN conductor shall be connected to the main earthing terminal only; + - 2) from the main earthing terminal to and within customer locations inside the building, the neutral conductor (N) shall be treated as a live conductor; + - 3) a dedicated PE shall be provided (see Figure 1, mode 2). +- c) Service by a TT or IT section of the outdoor mains distribution network: + - 1) the PE shall be derived via the main earthing terminal from the earthing network; + - 2) the dimensioning of the PE shall follow the rules of the TN-S system. + +If the outdoor mains distribution is of type IT or TT, a separation transformer dedicated to that building allows for the recommended TN-S installation. In this case the indoor mains installation must conform to mode 1, Figure 1. + +### **7.1 a.c. power line surge protective device** + +The a.c. mains input to the EEE should be equipped with a surge protective device. A specification for a low-voltage surge protective device is in advanced stages of preparation by IEC Subcommittee 37A. + +The surge protective device should be connected to the mains conductors on the load side of the circuit breaker. + +The surge protective device should be located where the leads for connection to the mains conductors, including the earthed (neutral) conductor, are as short as possible. Lead lengths that are less than 0.5 m are recommended. + +![Diagram for Mode 1: TN-S/TN-S. It shows the transition from an outdoor mains distribution (TN-S) to an indoor mains installation (TN-S). The outdoor side has two neutral (N) conductors and two protective earth (PE) conductors. The indoor side has a single neutral (N) conductor and a single PE conductor. The PE conductor is connected to a main earthing terminal, which is part of an earthing network. The earthing network includes a DC-return conductor and a ring conductor. The outdoor mains distribution is labeled 'Outdoor mains distribution'. Diagram for Mode 2: TN-C/TN-S. It shows the transition from an outdoor mains distribution (TN-C) to an indoor mains installation (TN-S). The outdoor side has a single PEN conductor. The indoor side has a single neutral (N) conductor and a single PE conductor. The PE conductor is connected to a main earthing terminal, which is part of an earthing network. The earthing network includes a DC-return conductor and a ring conductor. The outdoor mains distribution is labeled 'Outdoor mains distribution'. Diagram for Mode 3: IT/IT or TT/TT. It shows the transition from an outdoor mains distribution (IT or TT) to an indoor mains installation (IT or TT). The outdoor side has two neutral (N) conductors and two protective earth (PE) conductors. The indoor side has a single neutral (N) conductor and a single PE conductor. The PE conductor is connected to a main earthing terminal, which is part of an earthing network. The earthing network includes a DC-return conductor and a ring conductor. The outdoor mains distribution is labeled 'Outdoor mains distribution'.](cfef993dcc8fb513de79eb1f93cf26ae_img.jpg) + +**Mode 1: TN-S/TN-S** + +**Mode 2: TN-C/TN-S** + +**Mode 3: IT/IT or TT/TT** + +NOTE – Mode 1 is obligatory if a separation transformer is dedicated to the building and the TN-S system consequently originates at the transformer load side. + +K.35(18)\_F01 + +Diagram for Mode 1: TN-S/TN-S. It shows the transition from an outdoor mains distribution (TN-S) to an indoor mains installation (TN-S). The outdoor side has two neutral (N) conductors and two protective earth (PE) conductors. The indoor side has a single neutral (N) conductor and a single PE conductor. The PE conductor is connected to a main earthing terminal, which is part of an earthing network. The earthing network includes a DC-return conductor and a ring conductor. The outdoor mains distribution is labeled 'Outdoor mains distribution'. Diagram for Mode 2: TN-C/TN-S. It shows the transition from an outdoor mains distribution (TN-C) to an indoor mains installation (TN-S). The outdoor side has a single PEN conductor. The indoor side has a single neutral (N) conductor and a single PE conductor. The PE conductor is connected to a main earthing terminal, which is part of an earthing network. The earthing network includes a DC-return conductor and a ring conductor. The outdoor mains distribution is labeled 'Outdoor mains distribution'. Diagram for Mode 3: IT/IT or TT/TT. It shows the transition from an outdoor mains distribution (IT or TT) to an indoor mains installation (IT or TT). The outdoor side has two neutral (N) conductors and two protective earth (PE) conductors. The indoor side has a single neutral (N) conductor and a single PE conductor. The PE conductor is connected to a main earthing terminal, which is part of an earthing network. The earthing network includes a DC-return conductor and a ring conductor. The outdoor mains distribution is labeled 'Outdoor mains distribution'. + +**Figure 1 – Arrangements for the transition from the outdoor mains distribution network to the indoor mains** + +## 8 d.c. power distribution + +In many EEEs, d.c. power is generally distributed from a centralized d.c. power plant (bulk power plant), with the positive terminal connected to the common bonding network of the structure. This polarity is chosen to minimize corrosion in the outside cable plant, but there may be exceptions for specific transmission systems. + +The return conductor of the d.c. distribution system may be connected to the common bonding network (CBN) in either of two manners. It may be connected at only one location as an isolated d.c. return system (dc-I). Or the d.c. return may connect to the CBN at several locations (in which case some d.c. current is conducted by the CBN), as a d.c. return common to a CBN (dc C-CBN). Because of the small size of an EEE, the common-mode voltages (and the conversion to transverse mode voltage) supported by either of these two distribution systems should be comparable. + +NOTE – The CBN of an EEE comprises the bonding-bus conductors, a.c. power conduit, PE conductors, structural steel, and cable and racks. + +The bonding conductor that connects the return side of the d.c. power source to the interior bonding-bus should be capable of conducting the maximum fault current of the power system. Rapid operation of overcurrent protective devices is aided by connecting cable racks to the bonding-bus and providing electrical continuity between rack sections. + +Because of the close proximity of equipment in an EEE, it is important that equipment not be sensitive to voltage surges on the d.c. power caused by short-circuits in other equipment. + +## 9 Bonding configuration + +The bonding configuration in the EEE makes use of a CBN that includes all available metallic structural components and metallic cable trays and supports, augmented by an interior ring bonding-bus. The interconnected CBN reduces the magnitude of external surge current that is conducted on the framework of the enclosed equipment. + +This Recommendation covers the case where equipment is connected to the CBN in a mesh-BN configuration. This bonding configuration helps provide an equipotential environment for personnel in the close confines of the EEE. It also assures the presence of many parallel current paths to help de-energize a short-circuit in the d.c. supply and to mitigate the effects of surge currents. (Equipment can be connected to the CBN using other bonding configurations, but such cases are not covered in this Recommendation.) + +NOTE – This Recommendation requires minimum earthing and bonding configurations for remote electronic sites. Additional bonding network may be installed to improve the EMC performance. + +### 9.1 Main earthing terminal + +The principal location for the interconnection of earthing and bonding conductors of an EEE should be a busbar (or equivalent) that is within 2 m of the neutral terminal in the disconnecting apparatus of the power mains. This busbar serves as the main earthing terminal. + +Bonds should be placed between the main earthing terminal and: + +- the terminal used by the protective earth conductor in the entrance cabinet containing disconnecting apparatus for the power mains; +- the exterior earthing ring; +- the terminal, if present, connected to reinforcement bars or other concrete-encased conductors. + +### **9.2 Interior bonding-bus** + +The common bonding network of an EEE should include an interior bonding-bus composed of copper conductors. This bonding-bus provides potential equalization within the EEE and serves as a common connection between the main earthing terminal and metallic assemblies, such as equipment enclosures and frames. + +#### **9.2.1 Ring bonding-bus for AG/EEE and BG/EEE** + +For AG/EEEs and BG/EEEs, the interior bonding-bus should form a closed ring. The conductors of the ring bonding-bus should be attached to the walls or along the exterior of cable racks near the walls. The ring bonding-bus should be at a height that is accessible for visual inspection and for connection of equipment assemblies. + +The interior ring bonding-bus should be connected to the main earthing terminal, and should also be connected to any terminals in the EEE that attach to structural steel. + +A supplementary bonding-bus (Figure I.1) should be bridged across the ring for the bonding of equipment installed away from the walls. Both ends of the supplementary bonding-bus should be connected to the ring. + +Metallic wall sheathing should be used as a ring bonding-bus only if the metallic wall panels are designed for this purpose, continuity can be assured, and terminals are provided for attachment of bonding conductors. + +#### **9.2.2 Bonding-bus for EEC** + +It is not necessary for the bonding-bus in an EEC to form a closed ring. The bonding-bus conductors can alternatively be provided by low-impedance structural components. The structural components and their interconnections should be capable of conducting fault currents from the d.c. power supply, and should be protected against corrosion. + +The bonding-bus should be connected to the main earthing terminal of the EEC. + +### **9.3 Outside-plant cable entrance** + +#### **9.3.1 Location of entry ports** + +The separation of incoming services at their entry into the EEE and the entry of the mains power should be as small as possible. A separation of less than 4 m is recommended. The separation between the entry ports of the outside-plant cables and the main earthing terminal should also be less than 4 m (measured along walls). To avoid interference caused by magnetic field due to currents on power cables, it is usual practice to separate telecommunications cable from parallel unshielded power cables at least 10 cm, unless other shielding measures are taken. For an EEC, it is recommended that the cable entry ports be adjacent to the disconnecting apparatus of the power mains. + +#### **9.3.2 Bonding of metallic components** + +Metallic screens or other metallic structural components of the outside-plant cables should be bonded to the interior bonding-bus or directly to the main earthing terminal. The connection of the bonding conductor to the metallic components of the cables should be as close as practical to the cable entry port; the distance along the cable from the entry port to the bond connection should not exceed 2 m. If the outside-plant cables extend into the EEE beyond the bond connection, a second bond to the bonding-bus should be placed at the termination of the cables where they are spliced to internal cables. + +NOTE – If it is not possible to locate the entry port of the outside-plant cables within 4 m (measured along walls) of the main earthing terminal, an additional connection to the outside-plant cables is needed from at least one of the following: + +- a conductor directly connected to the exterior earthing ring; +- a conductor directly connected to a foundation earth electrode or to the steel reinforcing members of the structure; +- second interior ring bonding-bus. One ring bonding-bus should be near the ceiling, and the other near the floor. + +This additional connection to the outside-plant cables should be as close as practical to the entry ports, and not beyond 2 m. + +Metallic components of outside-plant optical cables should not extend into the EEE beyond the connection to the bonding-bus without interruption of electrical continuity. If such components are interrupted and extended into the EEE, they should be connected to the bonding-bus at the terminating equipment. + +In an EEC, the bond between the metallic components of an outside-plant cable and the bonding-bus should be as close to the entry port as practical. + +### **9.4 Equipment framework** + +All frames, racks and metallic enclosures in an EEE should be bonded to the interior bonding-bus. Metallic hardware, such as framing channels, air ducts, and permanently installed access ladders, should also be bonded together as well as to the bonding-bus. + +### **9.5 Surge protectors on communication pairs** + +If surge protectors are used on communication pairs, the common terminals of the protectors should be connected to the main earthing terminal. The metallic screens of cables entering the protector frames should be bonded to the common terminals of the protectors. + +### **9.6 Metallic walls** + +Metallic walls of an EEE should be bonded to the interior bonding-bus. + +## Appendix I + +### Example of bonding configurations and earthing of EEEs by use of ring bonding-bus + +(This appendix does not form an integral part of this Recommendation.) + +![Diagram illustrating bonding configurations and earthing of EEEs using a ring bonding-bus.](7efae06af3af43ffe5d4b956a679cf54_img.jpg) + +The diagram shows a 3D perspective view of an equipment frame. A 'Main earthing terminal' is connected to an 'Earthing network' via an 'Earthing conductor' (labeled 1). A 'Supplementary bonding-bus' is connected to the main earthing terminal. A 'Ring bonding-bus' is connected to the supplementary bonding-bus. An 'a.c. service enclosure' is connected to the ring bonding-bus via an 'Equipment bonding conductor' (labeled 2). The 'Equipment frame' is connected to the ring bonding-bus via a 'Protective conductor' (labeled 3). The diagram also shows connections to the earthing network and the earthing network itself. The text 'K.35(20)\_FI.1' is present in the bottom right corner of the diagram area. + +Diagram illustrating bonding configurations and earthing of EEEs using a ring bonding-bus. + +- ① Earthing conductor +- ② Equipment bonding conductor +- ③ Protective conductor + +**Figure I.1 – Example of bonding configurations and earthing of EEEs by use of ring bonding-bus** + +## Appendix II + +### Example of A.C. power line surge protective device + +(This appendix does not form an integral part of this Recommendation.) + +The a.c. mains input to the EEE should be equipped with a surge protective device. A specification for a low-voltage surge protective device is in advanced stages of preparation by IEC Subcommittee 37A. + +Because the lightning risk of outdoor cabinet cannot be higher than that of radio base station, it is recommended to specify the level of low-voltage surge protective device according to [ITU-T K.112] "Lightning protection, earthing and bonding: Practical procedures for radio base stations". + +Class II SPDs are recommended to be installed nearby the AC mains input of the EEE and EEC. SPD specification are shown in Table II.1. + +**Table II.1 – Example of SPD specification** + +| SPD type | Specification | Protective circuit mode | Power supply mode | +|--------------|---------------------------------------------|-------------------------|-------------------| +| Class II SPD | $I_n = 20 \text{ kA}$ (8/20 $\mu\text{s}$ ) | 3+1, Figure II.1 | Three-phase | +| | | Symmetric, Figure II.2 | Single-phase | + +The 3+1 type surge protection diagram is recommended for three-phase AC power supply systems, as shown in Figure II.1. + +![Surge protection diagram for three-phase AC showing an energy meter, three fuses (FU), three MOVs, and a GDT connected to an earthing bar.](6f341f415ee0f8c724e5d6daeb1e9b4a_img.jpg) + +``` +graph TD + subgraph Input + InL1[Line 1] + InL2[Line 2] + InL3[Line 3] + end + + EM[Energy meter] + InL1 & InL2 & InL3 --> EM + + subgraph SPD [Class II SPD] + FU1[FU] --- MOV1[MOV] + FU2[FU] --- MOV2[MOV] + FU3[FU] --- MOV3[MOV] + MOV1 & MOV2 & MOV3 --- GDT((GDT)) + end + + EM --> FU1 + EM --> FU2 + EM --> FU3 + + FU1 --> L1[L1] + FU2 --> L2[L2] + FU3 --> L3[L3] + + N[N] --- GDT + GDT --- PE[PE] + + EB[Earthing bar] --- PE + EB --- Ground[Ground Symbol] +``` + +The diagram illustrates a three-phase AC power supply system with surge protection. On the left, three input lines enter an 'Energy meter'. The output of the meter connects to three fuses labeled 'FU'. Each fuse is followed by a Metal Oxide Varistor (MOV) connected between the phase line and a common point. This common point is connected to a Gas Discharge Tube (GDT), which is then connected between the neutral line (N) and the protective earth (PE) line. The PE line connects to an 'Earthing bar', which is then connected to a ground symbol. The output lines are labeled L1, L2, L3 for the phases, N for neutral, and PE for protective earth. A label 'K.35(20)\_FII.1' is present in the bottom right corner of the diagram area. + +Surge protection diagram for three-phase AC showing an energy meter, three fuses (FU), three MOVs, and a GDT connected to an earthing bar. + +**Figure II.1 – Example of Surge protection diagram for three-phase AC** + +Symmetric SPD configuration is preferred for single-phase AC power supply, the protection diagram in Figure II.2 is a symmetric circuit, which is suitable in the case of the live conductor and neutral conductor with the risk of reverse connection. + +![Circuit diagram of a symmetric surge protection system for single-phase AC. It shows an energy meter connected to an AC source, followed by a Class II SPD containing MOVs and a GDT, and finally an earthing bar connected to ground. The diagram includes labels for L (Live), N (Neutral), and PE (Protective Earth) lines.](8fbdfc3d17fb1dae7b2d8f5a287fa9fc_img.jpg) + +``` + +graph LR + subgraph "Energy meter" + EM[Energy meter] + end + subgraph "Class II SPD" + MOV1[MOV] + MOV2[MOV] + MOV3[MOV] + GDT1[GDT] + end + L_in --- EM --- L_out[L] + N_in --- EM --- N_out[N] + PE_in --- EM --- PE_out[PE] + L_out --- MOV1 --- N_out + L_out --- MOV2 --- GDT1 + N_out --- MOV3 --- GDT1 + GDT1 --- EB[Earthing bar] + EB --- GND[Ground] + +``` + +The diagram illustrates a symmetric surge protection configuration for single-phase AC. On the left, an AC source is connected to an energy meter. The output of the energy meter feeds into a Class II SPD, which is enclosed in a dashed box. Inside the Class II SPD, there are three MOV (Metal Oxide Varistor) components and one GDT (Gas Discharge Tube). One MOV is connected between the L (Live) and N (Neutral) lines. Two other MOVs are connected from L and N respectively to a common point, which then connects through a GDT to the PE (Protective Earth) line and the earthing bar. The earthing bar is connected to ground. The output of the Class II SPD is connected to a load, represented by a box on the right. The diagram is labeled with 'Energy meter', 'Class II SPD', 'MOV', 'GDT', 'Earthing bar', 'L', 'N', 'PE', and 'K.35(20)\_FII.2'. + +Circuit diagram of a symmetric surge protection system for single-phase AC. It shows an energy meter connected to an AC source, followed by a Class II SPD containing MOVs and a GDT, and finally an earthing bar connected to ground. The diagram includes labels for L (Live), N (Neutral), and PE (Protective Earth) lines. + +**Figure II.2 – Example of Symmetric surge protection diagram for single-phase AC** + +## Appendix III + +### Example of Bonding-bus for EEC + +(This appendix does not form an integral part of this Recommendation.) + +The EEC shall be equipped with the main earthing terminal, and its sectional area shall be $> 16 \text{ mm}^2$ . The main earthing terminal shall be led out from two different directions and connected to the earthing network. The main earthing terminal shall be able to connect at least 8 bonding lines. + +It is not necessary for the bonding-bus in an EEC to form a closed ring. The bonding-bus conductors can alternatively be provided by low-impedance structural components. The structural components and their interconnections should be capable of conducting fault currents from the d.c. power supply, and should be protected against corrosion. + +The metal part of the EEC shall be interconnected and connected to the bonding-bus, and the protective earth (PE) of equipment in the EEC shall be connected to the bonding-bus with a clear earthing label. + +The bonding-bus should be connected to the main earthing terminal of the EEC, and the connection resistance between any two points shall be less than $0.1 \Omega$ . + +In case of use of fibre cable with metallic parts, the connection of these parts to the main earthing terminal shall be done following local regulations. + +![Figure III.1 – Example of bonding configurations and earthing of EEC](51db757d054ce1ce83c436a3578b56ca_img.jpg) + +``` + + graph TD + AC[A.C. Power line] --> MainCB[Main CB] + MainCB --> SPD[CLASS II SPD] + SPD --> SwitchCB[Switch CB] + SwitchCB --> Rectifier[Rectifier module] + Rectifier --> ProtTerminals[Protective Terminals - 3] + ProtTerminals -.-> BondingBus[Bonding bus - 4] + BondingBus --- MainEarth[Main earthing terminal - 1] + BondingBus --- ODFEarth[ODF earthing terminal] + MainEarth --- EarthNet[Earthing network] + EquipCab[Equipment cabinet] -.-> MainEarth + Fibre[Fibre cable sheath/core] --- ODFEarth + subgraph Modules + BBU + EquipCab + Optical[Optical transmission module] + Monitor[Monitoring module] + end + subgraph Bottom + Battery + CableArea[Cable threading area] + end + +``` + +① Earthing conductor   ③ Protective conductor +② Equipment bonding conductor   ④ Bonding bus + +K.35(20)\_FIII.1 + +Figure III.1 – Example of bonding configurations and earthing of EEC + +**Figure III.1 – Example of bonding configurations and earthing of EEC** + +## Bibliography + +- [b-YD/T 1537] China industrial standard YD/T 1537-2015, *Outdoor cabinets for telecommunication system*. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.44-201910-I_PDF-E/raw.md b/marked/K/T-REC-K.44-201910-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..2962003f1e4dab58bf16a17bb312edd13fee88cc --- /dev/null +++ b/marked/K/T-REC-K.44-201910-I_PDF-E/raw.md @@ -0,0 +1,2451 @@ + + +International Telecommunication Union + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.44** + +(10/2019) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Resistibility tests for telecommunication +equipment exposed to overvoltages and +overcurrents – Basic Recommendation** + +Recommendation ITU-T K.44 + +ITU-T + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a red lightning bolt striking it, symbolizing telecommunications. To the right of the globe, the text "International Telecommunication Union" is written in blue, with the acronym "ITU" in a larger, bold blue font. + +ITU logo + +International +Telecommunication +Union + + + +# Recommendation ITU-T K.44 + +# Resistibility tests for telecommunication equipment exposed to overvoltages and overcurrents - Basic Recommendation + +## Summary + +Recommendation ITU-T K.44 seeks to establish fundamental test methods and criteria for the resistibility of telecommunication equipment to overvoltages and overcurrents. + +Overvoltages or overcurrents covered by this Recommendation include surges due to lightning on or near the line plant, short-term induction of alternating voltages from adjacent electric power lines or electrified railway systems, earth potential rise due to power faults and direct contacts between telecommunication lines and power lines. + +Major changes compared with the 2018 version of this Recommendation include: + +- removed Appendices I and II and replaced them with ITU-T K.44 supplements; +- added new twisted-pair transverse/differential surge test circuit; +- added Ethernet insulation resistance test to avoid port power cross test; +- revised the test schematics to improve clarity. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|--------------------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.44 | 2000-02-25 | 5 | 11.1002/1000/4907 | +| 2.0 | ITU-T K.44 | 2003-07-29 | 5 | 11.1002/1000/6496 | +| 3.0 | ITU-T K.44 | 2008-04-13 | 5 | 11.1002/1000/9403 | +| 4.0 | ITU-T K.44 | 2011-11-13 | 5 | 11.1002/1000/11422 | +| 5.0 | ITU-T K.44 | 2012-05-29 | 5 | 11.1002/1000/11629 | +| 5.1 | ITU-T K.44 (2012) Cor. 1 | 2013-03-16 | 5 | 11.1002/1000/11902 | +| 5.2 | ITU-T K.44 (2012) Amd. 1 | 2015-04-22 | 5 | 11.1002/1000/12406 | +| 5.3 | ITU-T K.44 (2012) Amd. 2 | 2015-12-14 | 5 | 11.1002/1000/12679 | +| 6.0 | ITU-T K.44 | 2016-06-29 | 5 | 11.1002/1000/12869 | +| 7.0 | ITU-T K.44 | 2017-05-24 | 5 | 11.1002/1000/13128 | +| 8.0 | ITU-T K.44 | 2018-10-22 | 5 | 11.1002/1000/13631 | +| 9.0 | ITU-T K.44 | 2019-10-22 | 5 | 11.1002/1000/13952 | + +## Keywords + +1.2/50-8/20, 10/700, Basic; enhanced, Ethernet, external port, internal port, overcurrent, overvoltage, power contact, power over Ethernet (PoE), power induction, remote power feed, resistibility test circuit, special resistibility, surges, telecommunication equipment, transverse. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2019 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|---------|--------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions, abbreviations and symbols..... | 2 | +| 3.1 | Definitions ..... | 2 | +| 3.2 | Abbreviations and acronyms ..... | 7 | +| 3.3 | Symbols ..... | 9 | +| 4 | Overvoltage and overcurrent conditions..... | 9 | +| 5 | Resistibility requirements ..... | 9 | +| 5.1 | Basic resistibility requirement ..... | 10 | +| 5.2 | Intermediate resistibility requirement..... | 10 | +| 5.3 | Enhanced resistibility requirement ..... | 10 | +| 5.4 | Special resistibility requirement ..... | 10 | +| 6 | Equipment boundary..... | 11 | +| 7 | Test conditions..... | 11 | +| 7.1 | Interface ports ..... | 11 | +| 7.2 | Test types..... | 12 | +| 7.3 | Test conditions..... | 13 | +| 7.4 | Test schematics..... | 15 | +| 8 | Protection coordination..... | 15 | +| 8.1 | General ..... | 15 | +| 8.2 | Lightning ..... | 15 | +| 8.3 | Power induction, earth potential rise and power contact..... | 16 | +| 8.4 | Special test protector ..... | 16 | +| 8.5 | Selection of the agreed primary protector ..... | 17 | +| 9 | Acceptance criteria ..... | 17 | +| 10 | Tests..... | 17 | +| 10.1 | External symmetric pair port ..... | 23 | +| 10.2 | External coaxial port..... | 24 | +| 10.3 | External d.c. and a.c. dedicated power feeding ports ..... | 25 | +| 10.4 | External a.c. mains power port ..... | 26 | +| 10.5 | Internal ports..... | 27 | +| 10.6 | Intra-system ports ..... | 27 | +| Annex A | – Test schematics..... | 29 | +| A.1 | Introduction ..... | 29 | +| A.2 | Equipment..... | 29 | +| A.3 | Test generators..... | 37 | +| A.4 | Waveform generation ..... | 39 | + +| | Page | +|-----------------------------------------------------------|-------------| +| A.5 Powering, coupling, decoupling and terminations ..... | 40 | +| A.6 Test schematics for different types of ports ..... | 56 | +| Bibliography..... | 84 | + +# Recommendation ITU-T K.44 + +# Resistibility tests for telecommunication equipment exposed to overvoltages and overcurrents – Basic Recommendation + +# 1 Scope + +This Recommendation describes resistibility tests for all telecommunication equipment against overvoltages and overcurrents for use by network operators and manufacturers. + +This Recommendation applies to all telecommunication equipment connected to external or intra-building metallic conductors. It should be read in conjunction with [ITU-T K.11] and [ITU-T K.39], which deal with the general economic and technical aspects of protection. + +This Recommendation does not specify either test levels or particular acceptance criteria for specific equipment. + +The appropriate test levels and test points are contained in the specific product family or product Recommendation. + +Therefore, this Recommendation has to be used together with the product family or product Recommendation dealing with the resistibility requirements relevant to the equipment to be tested. + +If a product family or product Recommendation or clause of it differs from this basic Recommendation, the product family or product Recommendation applies. As product Recommendations are updated, they should be coordinated with and refer to this Recommendation. + +This Recommendation assumes that the earthing and bonding configurations comply with the appropriate Recommendation related to the type of installation. + +The tests are type tests and, although they are applicable to a complete system, it is recognized that they may be applied to individual items of equipment during development and design work. In performing the tests, it is necessary to take into account any conditions, either in the unit under test or elsewhere, which may affect the results. + +Electrostatic discharge (ESD) testing is not covered by this Recommendation, and [IEC 61000-4-2] should be followed. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.11] Recommendation ITU-T K.11 (2009), *Principles of protection against overvoltages and overcurrents*. +- [ITU-T K.12] Recommendation ITU-T K.12 (2010), *Characteristics of gas discharge tubes for the protection of telecommunications installations*. +- [ITU-T K.27] Recommendation ITU-T K.27 (2015), *Bonding configurations and earthing inside a telecommunication building*. +- [ITU-T K.28] Recommendation ITU-T K.28 (2012), *Parameters of thyristor-based surge protective devices for the protection of telecommunication installations*. + +- [ITU-T K.39] Recommendation ITU-T K.39 (1996), *Risk assessment of damages to telecommunication sites due to lightning discharges.* +- [IEC 60050-701] IEC 60050-701 (2016), *International Electrotechnical Vocabulary. Chapter 701: Telecommunications, channels and networks.* +[http://webstore.iec.ch/webstore/webstore.nsf/ArtNum\\_PK/433?OpenDocument](http://webstore.iec.ch/webstore/webstore.nsf/ArtNum_PK/433?OpenDocument) +- [IEC 60060-1] IEC 60060-1 (2010), *High-voltage test techniques – Part 1: General definitions and test requirements.* + +- [IEC 60664-2-1] IEC 60664-2-1 (2011), *Insulation coordination for equipment within low-voltage systems – Part 2-1: Application guide – Explanation of the application of the IEC 60664 series, dimensioning examples and dielectric testing.* +[http://webstore.iec.ch/webstore/webstore.nsf/ArtNum\\_PK/44787?OpenDocument](http://webstore.iec.ch/webstore/webstore.nsf/ArtNum_PK/44787?OpenDocument) +- [IEC 61000-4-2] IEC 61000-4-2 (2008), *Electromagnetic compatibility (EMC) – Part 4-2: Testing and measurement techniques – Electrostatic discharge immunity test.* + +- [IEC 61643-12] IEC 61643-12 (2008), *Low-voltage surge protective devices – Part 12: Surge protective devices connected to low-voltage power distribution systems – Selection and application principles.* + +- [IEC 62475] IEC 62475 (2010), *High-current test techniques – Definitions and requirements for test currents and measuring systems.* +[http://webstore.iec.ch/webstore/webstore.nsf/ArtNum\\_PK/44542](http://webstore.iec.ch/webstore/webstore.nsf/ArtNum_PK/44542) + +# 3 Definitions, abbreviations and symbols + +## 3.1 Definitions + +To assist in understanding the various definitions used in this Recommendation, refer to Figure 3-1. This figure shows elements associated with protecting the equipment that may be in an installation. Not all of these elements are expected to be used in an installation. + +![Diagram illustrating protection elements within a building, shelter, structure, or equipment housing. The diagram shows a central 'Immutable part of equipment (black box)' containing 'Protection assembly (telecoms)', 'Electronics' (with 'Protection component'), and 'Protection assembly (power)'. This central box is connected to 'Primary protection (telecoms)' on the left and 'Primary protection (power)' on the right. All three primary protection units are connected to a common 'Main earthing terminal' at the bottom, which is then connected to earth. The entire setup is enclosed within 'Equipment interface' boundaries. The diagram is labeled K.44(17)_F3-1.](ebff22fb5dd6f50a90e44dca0f82f285_img.jpg) + +Building, shelter, structure or equipment housing + +Diagram illustrating protection elements within a building, shelter, structure, or equipment housing. The diagram shows a central 'Immutable part of equipment (black box)' containing 'Protection assembly (telecoms)', 'Electronics' (with 'Protection component'), and 'Protection assembly (power)'. This central box is connected to 'Primary protection (telecoms)' on the left and 'Primary protection (power)' on the right. All three primary protection units are connected to a common 'Main earthing terminal' at the bottom, which is then connected to earth. The entire setup is enclosed within 'Equipment interface' boundaries. The diagram is labeled K.44(17)\_F3-1. + +NOTE – The arrangement of the blocks and bonding conductors inside of the building, shelter, structure or equipment housing is to assist in their identification and does not infer an optimum physical arrangement from a protection point of view. + +**Figure 3-1 – Illustration of protection elements** + +This Recommendation uses the following terms defined here and elsewhere: + +**3.1.1 1.2/50-8/20 combination wave generator (CWG):** Generator producing a 1.2/50 open-circuit voltage waveshape and an 8/20 short-circuit current waveshape. + +**3.1.2 access network (AN):** That part of the overall telecommunication network that is located between a telecommunication centre and the customer premises building. + +**3.1.3 agreed primary protection:** An agreed primary protector is the type of surge protective device (SPD) that will be used to protect the equipment. An agreed primary protector may be a specific SPD or a range of SPDs that comply with a particular Recommendation, standard or specification. The agreed primary protector is often specified by the network operator, but it may be the result of discussions between the network operator and the equipment manufacturer. The agreed primary protector can be 'nothing' if it has been agreed that no external protection elements need to be used for the equipment. + +**3.1.4 class II equipment [b-IEC 62368-1]:** Equipment in which protection against electric shock does not rely on basic insulation only, but in which a supplementary safeguard is provided, there being no provision for protective earthing or reliance upon installation conditions. + +**3.1.5 coaxial cable [b-IEC 60194]:** Cable in the form of a central wire surrounded by a conductor tubing or sheathing that serves as a screen and return. + +**3.1.6 coupling element:** A coupling element is a low impedance component, under surge conditions, used to connect the surge generator to the port being tested or to couple an untested port to earth. + +**3.1.7 customer premises equipment (CPE):** Equipment intended to be directly connected to the termination of a public telecommunication network in a customer's premises. + +**3.1.8 decoupling element:** A component with a suitable impedance to reduce the surge amplitude into auxiliary equipment or terminations. + +**3.1.9 dedicated power feed (dpf):** A power feed provided by a dedicated telecommunication cable that leaves the building and is used exclusively to provide the power feed. See also clause 3.1.29. + +**3.1.10 embedded primary protection:** High current-carrying protection components, mounted inside the equipment, that form part of the equipment port inherent protection. + +NOTE – As mounted high current-carrying protection components are used, field replacement is not usually possible. + +**3.1.11 external cable termination point:** The point where the external cable terminates and connects to the building cabling. + +NOTE – This is also the point where SPDs would be installed, if required. + +**3.1.12 foldback protection device:** A clamping-type voltage limiter that utilizes transistor action to create a re-entrant or "foldback" characteristic. + +**3.1.13 high current-carrying protection components:** Surge protective component (SPC) that is typically used in a primary protector surge protective device (SPD) and which can conduct the SPD rated surge current + +NOTE 1 – In most cases the high current-carrying protection component will be a voltage limiter that diverts the surge current, e.g. a gas discharge tube (GDT). + +NOTE 2 – These components can be used in equipment ports providing inherent primary protection that removes the need for external primary protection. + +**3.1.14 IEEE 802.3 power over Ethernet (PoE):** Technology simultaneously using an Ethernet cable for normal twisted-pair signalling and a DC powering feed over two or four twisted pairs. + +**3.1.15 inherent protection:** Protection that is provided within the equipment either by virtue of its intrinsic characteristics, by specific design, or by suitable protection components. + +**3.1.16 insulation** [IEC 60664-2-1]: That part of an electrotechnical product that separates the conducting parts at different electrical potentials. + +**3.1.17 insulation coordination** [IEC 60664-2-1]: Mutual correlation of insulation characteristics of electrical equipment taking into account the expected micro-environment and other influencing stresses. + +**3.1.18 integrated primary protection:** Primary protection surge protective devices (SPDs), mounted inside the equipment, that form part of the equipment port inherent protection + +NOTE – By definition an SPD is a combination of a protection circuit and holder, which should allow field replacement. + +**3.1.19 interface ports:** + +**3.1.19.1 external port:** Any interface on the equipment that is connected to a cable that exits the building runs outdoor and which may be subjected to conducted a.c. surges and lightning surges. + +NOTE – Clause A.2.1 provides guidance on classification of ports. + +**3.1.19.1.1 coaxial cable port:** The port connects to a coaxial cable. + +**3.1.19.1.2 dedicated power feed port:** The port connects to a dedicated power feed cable. + +**3.1.19.1.3 mains power port:** The port connects to a cable that provides mains power. + +**3.1.19.1.4 symmetric pair port:** The port connects to a cable with metallic symmetric pair conductors (see [b-ITU-T K.46]). The cable may be shielded or non-shielded. The port may connect to a single pair or multiple pairs. + +**3.1.19.2 internal port:** An internal port is any interface on the equipment that is connected to a cable that does not exit the building and may be subjected to short duration induced transient surges. + +NOTE – Clause A.2.1 provides guidance on classification of ports. + +**3.1.19.2.1 d.c. power interface ports:** The port connects to a cable, e.g., a shielded cable that provides d.c. power, e.g., –48 V. + +**3.1.19.2.2 multiple port:** Term that is used to describe equipment with more than one type of port, e.g., a mains port and an external symmetric pair port. + +**3.1.19.2.3 screened/shielded cable port:** Port providing a connection for the screen/shield of a cable. + +NOTE – In some cases, such as Ethernet ports, unshielded/unshielded cables may be connected to the port. + +**3.1.19.2.4 unscreened/unshielded cable port:** Port that does not provide a connection for the screen/shield of a cable. + +**3.1.19.3 intra-building system port:** A port used for interconnecting equipment modules of the same system within a telecommunication centre building. The interconnecting cabling is under the control of the equipment manufacturer. + +**3.1.20 isolating transformer** [b-IEC 61558-1]: Transformer with protective separation between the input winding(s) and output winding(s). + +**3.1.21 IT power distribution system:** An IT power system is isolated from earth, except that one point may be connected to earth through an impedance or a voltage limiter. The parts of the equipment to be earthed are connected to earth electrodes at the user premises. + +**3.1.22 multiservice surge protective device** [IEC 61643-12]: A surge protective device providing protection for two or more services such as power, telecommunication and signalling in a single enclosure in which a reference bond is provided between services during surge conditions. + +**3.1.23 positive temperature coefficient thermistor (PTC):** Thermistor in which the resistance increases with increasing temperature throughout the useful part of its characteristic. The PTC thermistors covered in this Recommendation typically exhibit a very sharp increase in resistance over a narrow temperature range. + +**3.1.24 primary protection:** Means by which the majority of the surge stress is prevented from propagating beyond a designated location (preferably the building entrance point). + +**3.1.25 primary protector:** An SPD used for the primary protection of an installation at the location (preferably the building entrance point) where it diverts most of the surge current and prevents the majority of the surge stress from propagating further into the installation. This SPD must be accessible, removable and have equipotential bonding. + +**3.1.26 protection coordination:** The act of ensuring that all protection elements, internal and external to the equipment, react in such a way so as to limit the amount of energy, voltage or current to levels such that damage does not occur to protection elements or equipment. + +**3.1.27 rated impulse voltage (insulation)** [IEC 60664-2-1]: Impulse withstand voltage value assigned by the manufacturer to the equipment or to a part of it, characterizing the specified withstand capability of its insulation against transient overvoltages. + +**3.1.28 rated insulation voltage** [IEC 60664-2-1]: RMS withstand voltage value assigned by the manufacturer to the equipment or to a part of it, characterizing the specified (long-term) withstand capability of its insulation. + +**3.1.29 remote power feed:** A remote power feed is a power feed provided by symmetric signal pairs or inner conductors of coaxial circuits simultaneously used for signal transmission. Remote power feeds complying with the requirements for a TNV circuit are not classified as a remote power + +feed. The requirements for a TNV circuit are provided in [b-IEC 60950-1], and a dedicated power feed (dpf) is defined in clause 3.1.9. + +**3.1.30 resistibility:** The ability of telecommunication equipment or installations to withstand, in general, without damage, the effects of overvoltages or overcurrents, up to a certain specified extent, and in accordance with a specified criterion. + +NOTE – Resistibility is considered to cater for the needs of the whole of the telecommunication network, i.e., all types of networks, public and private, as well as any equipment installed in or connected to this network. The resistibility requirements are based on the following electromagnetic phenomena: lightning, power induction, earth potential rise and low-voltage power contact. + +**3.1.31 screen, shield, (US)** [b-IEC 60065-151]: Device intended to reduce the penetration of an electric, magnetic or electromagnetic field into a given region. + +**3.1.32 screened cable, shielded cable (US):** Group of one or more pairs of twisted wires balanced with respect to earth, assembled together and covered by a continuous metallic sheath. + +**3.1.33 shield** [b-IEC 60065-151]: Barrier or enclosure provided for mechanical protection, which may also have the function of a screen. + +**3.1.34 special test protector:** The special test protector is a component or circuit used to replace the agreed primary protector for the purposes of confirming coordination. The special test protector limiting characteristics ensure that the voltage and current levels at the input of the equipment will be higher during the test than in service and provides a level of guarantee that the equipment will be protected by the addition of primary protection. + +**3.1.35 surge protective component (SPC)** [ITU-T K.11]: Constituent part of a surge protective device which cannot be physically divided into smaller parts without losing its protective function. + +NOTE 1 – This is a modification to definition of item 151-11-21 (component) in the International Electrotechnical Vocabulary [b-IEC 60050-151]. + +NOTE 2 – The protective function is non-linear; amplitude restriction effectively begins when the amplitude attempts to exceed the predetermined threshold value of the component. + +**3.1.36 surge protective device (SPD):** Device that restricts the voltage of a designated port or ports, caused by a surge, when it exceeds a predetermined level: + +- 1) secondary functions may be incorporated, such as a current-limiting device to restrict a terminal current; +- 2) typically, the protective circuit has at least one non-linear voltage-limiting surge protective component; +- 3) an SPD is a combination of a protection circuit and holder. + +**3.1.37 telecommunication:** Any transmission, emission or reception of signs, signals, writing, images and sounds or intelligence of any nature by wire, radio, optical or other electromagnetic systems [IEC 60050-701]. + +**3.1.38 telecommunication centre:** A telecommunication facility where the earthing and bonding is in accordance with [ITU-T K.27]. + +**3.1.39 telecommunication network:** A transmission medium intended for communication between equipment that may be located in separate buildings. + +NOTE 1 – The term telecommunication network is defined in terms of its functionality, not its electrical characteristics. + +NOTE 2 – A telecommunication network may be: + +- publicly or privately owned; +- subject to transient overvoltages due to atmospheric discharges and faults in power distribution systems; + +- subject to permanent port to earth (common mode) voltages induced from nearby power lines or electric traction lines. + +NOTE 3 – Examples of telecommunication networks are: + +- public switched telephone network (PSTN); +- next generation network (NGN); +- public data network; +- a private network with electrical interface characteristics similar to the above. + +**3.1.40 termination component:** A component used to simulate the connection of auxiliary equipment to a tested or untested port. + +**3.1.41 thermistor:** Thermally sensitive semiconducting resistor whose primary function is to exhibit an important change in electrical resistance with a change in body temperature. + +**3.1.42 transverse (differential) mode voltage:** The voltage at a given location between two conductors, or pairs of conductors, of a group. + +**3.1.43 trunk network (TNW):** That part of the telecommunication network that is located between two telecommunication centres and that provides the communication between the centres. + +**3.1.44 TT power distribution system:** A TT power distribution system has one point directly earthed, the parts of the equipment required to be earthed being connected at the user premises to earth electrodes that are electrically independent of the earth electrodes of the power distribution system. + +## 3.2 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|----------------------------------------------------------------| +| a.c. | Alternating Current | +| AE | Auxiliary Equipment | +| AN | Access Network | +| ANE | Access Network Equipment | +| AUX | Auxiliary | +| BN | Bonding Network | +| CBN | Common Bonding Network | +| CPE | Customer Premises Equipment | +| d.c. | Direct Current | +| DMT | Discrete Multitone | +| dpf | dedicated power feed | +| ECL | Electronic Current Limiter | +| ECTP | External Cable Termination Point | +| EPR | Earth Potential Rise | +| ESD | Electrostatic Discharge | +| EUT | Equipment Under Test | +| GDT | Gas Discharge Tube | +| HV | High Voltage (power line of a.c. voltage > 36 kV and < 200 kV) | + +| | | +|------------------|----------------------------------------------------------------| +| IBN | Isolated Bonding Network | +| ISDN | Integrated Services Digital Network | +| LE | Local Exchange | +| LI | Line Interface | +| LT | Line Termination | +| LV | Low Voltage (power line of a.c. voltage < 1 kV) | +| MDF | Main Distribution Frame | +| MET | Main Earthing Terminal | +| MOV | Metal Oxide Varistor | +| MSPD | Multiservice Surge Protective Device | +| MV | Medium Voltage (power line of a.c. voltage > 1 kV and < 35 kV) | +| n/a | not applicable | +| NGN | Next Generation Network | +| NT | Network Termination | +| PD | Powered Device | +| PoE | Power over Ethernet | +| POTS | Plain Old Telephone System | +| PS | Power Supply | +| PSE | Power Sourcing Equipment | +| PSTN | Public Switched Telephone Network | +| PTC | Positive Temperature Coefficient thermistor | +| RMS | Root Mean Square | +| ROEP | Rise of Earth Potential | +| RSE | Remote Switching Equipment | +| SHDSL | Single-pair High-speed Digital Subscriber Line | +| SOHO | Small Office, Home Office | +| SPC | Surge Protective Component | +| SPD | Surge Protective Device | +| SLIC | Subscriber Line Integrated Circuit | +| SSA | Solid State Arrester | +| SSOP | Solid State Overcurrent Protector | +| STP | Special Test Protector | +| STP E | Shielded Twisted Pair Ethernet | +| SW | Switch | +| TCE | Telecommunication Centre Equipment | +| TDD | Time Division Duplex | +| TN-C | Type of power distribution system | + +| | | +|------------------|-----------------------------------------| +| TNV | Telecommunication Network Voltage | +| TNW | Trunk Network | +| USB | Universal Serial Bus | +| UTP E | Unshielded Twisted Pair Ethernet | +| VDSL | Very high speed Digital Subscriber Line | +| WLAN | Wireless Local Area Network | +| XDSL | any type of Digital Subscriber Line | + +## 3.3 Symbols + +This Recommendation uses the following symbols: + +| | | +|------------------|--------------------------------------------------------| +| $U_c$ | d.c. charge voltage of the surge generator | +| $U_{c(\max)}$ | Maximum d.c. charge voltage of the surge generator | +| $U_{a.c.(\max)}$ | Maximum a.c. (open) voltage for the a.c. voltage tests | + +# 4 Overvoltage and overcurrent conditions + +Aspects of overvoltage or overcurrent covered by this Recommendation are: + +- surges due to lightning strokes on or near to the line plant; +- large currents in common wiring or components when overvoltages or overcurrents occur simultaneously on a number of lines; +- large currents flowing into the equipment when high current-carrying protection components, which eliminate the need for primary protection, are integral to the equipment; +- short-term induction of alternating voltages from adjacent electric power lines or electrified railway systems, usually when these lines or systems develop faults; +- earth potential rise (EPR) due to power faults; +- direct contacts between telecommunication lines and mains power lines; +- transient surges on mains-voltage lines; +- the potential difference which can occur between a TT power distribution system or IT power distribution system and the telecommunication system. + +# 5 Resistibility requirements + +Telecommunication lines, remote (dedicated) power feeding lines and mains power lines are influenced in the practical environment by lightning or power lines. The several degrees of influence and protection measures are described in [ITU-T K.11]. With reference to the resistibility of telecommunication equipment connected to metallic conductors, there may be different resistibility requirements in different environments. An example is the different power systems described in [b-ITU-T K.66]. In particular, the TT and IT power systems, which have no connection to the building main earthing terminal (MET), result in higher surges with respect to the MET. It is for administrations or network operators to select the appropriate resistibility requirement from the product family or product Recommendations. In the interest of reducing the number of equipment designs, only the basic and enhanced requirements are specified in the product Recommendations at this point in time. + +While the product Recommendations do not provide special resistibility requirements, it is acknowledged that special conditions can exist where even the enhanced resistibility requirements are not sufficient. + +Some countries may have different power systems in some areas or it is not possible to install primary protection. [b-ITU-T K.98] shows that multiservice surge protective devices (MSPDs) are an effective way to protect equipment particularly collocated equipment. To protect equipment connected to long internal cables it may be desirable to use MSPDs for the protection of internal ports. MSPDs are readily available for this purpose. This information should be kept in mind when selecting the requirements. It is better to use the higher requirements for all equipment. + +## **5.1 Basic resistibility requirement** + +This applies to equipment intended for use in: + +- environments with a low exposure. The equipment protection is achieved by the inherent protection; +- environments with a high exposure, equipment protection is achieved by the inherent protection and adding the agreed primary protection; +- ports that rely on insulation coordination can add an agreed isolating transformer device of higher rated voltage withstand instead of the agreed primary protection. + +## **5.2 Intermediate resistibility requirement** + +This resistibility requirement may be applied to the cases that the basic resistibility is not sufficient considering the aspects of environmental condition, and/or customer's requirement on reliability of service, nevertheless, the enhanced resistibility cannot be applied due to the cost. It has better resistibility than the basic requirement, and also it is achieved by relatively small cost addition and has a good price-performance ratio. + +## **5.3 Enhanced resistibility requirement** + +Where the basic resistibility requirements are not sufficient due to harsh environmental conditions, national regulations, economic and technical considerations, installation standards or reliability of service requirements, network operators may request the enhanced resistibility requirement. + +Examples of when "enhanced" resistibility levels may be required include when: + +- the Pt of power induction and EPR surges exceed 1 A2s; +- primary protector SPDs are not normally installed; +- equipotential bonding at customer premises is difficult to achieve, e.g., the bond wire is greater than 1.5 m long; +- customer equipment has more than one type of port, e.g., mains port plus external telecommunication port or mains port plus internal ports. + +## **5.4 Special resistibility requirement** + +There are circumstances where even the enhanced resistibility requirements are not sufficient for customer premises due to environmental conditions, national regulations, economic and technical considerations, installation standards or reliability of service requirements. Network operators may then request the special resistibility requirement. + +The special resistibility requirement applies when all of the following conditions coexist: + +- IT or TT power system; +- earthing and bonding is not installed in compliance with [b-ITU-T K.66]; +- primary protection is not installed in compliance with [b-ITU-T K.66] when required by a risk assessment; +- there is difficulty in installing MSPDs. + +In this case, the network operator may need to request special resistibility requirements. Some guidance and possible test levels are provided in Annex A of [b-ITU-T K.21] and [b-ITU-T K.45]. Annex A of [b-ITU-T K.21] and [b-ITU-T K.45] contain both test descriptions and requirements for special resistibility requirements. It is proposed that the test requirements, described in clause 7, be amended as indicated. + +# 6 Equipment boundary + +The variations of different types of equipment make it necessary for the equipment to be seen as a "black-box" having several ports, a, b, c, d, e and f, etc., and E (earth). It is possible that some protective devices have already been provided in the equipment, either on the printed circuit board, etc., or connected to its ports. For the purpose of these tests, manufacturers are expected to define the boundaries of the "black-box" and any protective device which is included must be considered as an immutable part of the equipment (e.g., small exchange in street cabinet, multiplexer, customer premises equipment (CPE)). Where high current-carrying protection components are used within the equipment, see clause 10.1.1. Where any auxiliary telecommunication wire is provided, e.g., to an extension or as a signalling earth, these wires should be seen to extend the number of terminals to be tested, e.g., a, b, c, d, e and f and E for earth. + +# 7 Test conditions + +## 7.1 Interface ports + +### 7.1.1 Port classification + +There are three different ports: external, internal and intra-system. + +- 1) External ports are: + - symmetric pair; + - coaxial cable; + - dedicated power feed (dpf); + - a.c. mains power. +- 2) Internal ports are: + - unshielded symmetric pair cables; + - shielded cable including symmetric and asymmetric pair shielded cables and coaxial cables; + - floating DC powering; + - earth bonded DC powering. + +NOTE – Overview of floating and earth bonded DC powering: + +DC power: floating and earth-bonded can be single polarity or dual voltage polarity. The plus or minus polarity of single polarity DC powering may be connected to the local equipotential earthing system making the supply earth bonded. Alternatively, the single polarity DC powering can be made floating by not making a direct connection to the local equipotential earthing system. + +Dual polarity DC powering can have two configurations. The first configuration consists of two series connected single polarity supplies arranged to give the three voltage polarities of plus, 0 V and minus. Typically, at the DC power source the 0 V is earth bonded. The second configuration consists of a single polarity supply, which has two equal value resistors in series connected across the DC power feed. The connection between the two resistors is earth bonded making the supply effectively float with equal plus and minus voltages with respect to earth, e.g. a single 400 V d.c. supply would have feed voltages of +200 V d.c. and –200 V d.c. The reason for this configuration is to limit the current of any feed conductor to earth by the use of high value resistors and so meet safety standard touch- + +current requirements. For more information on bonding configurations and earthing inside a telecommunication building see [ITU-T K.27]. + +3) Intra-system ports within a telecommunication centre switching system are expected to be interconnected by short cables or shielded cables (e.g., cable screen or cable trays) under the control of the manufacturer. As these types of ports are not normally exposed to damaging overvoltages, requirements have not been specified. + +### 7.1.2 Interface ports + +Ports may connect to different cable types and different service types. This is explained in clause A.2. + +## 7.2 Test types + +The following types of test need to be performed on equipment, depending on the port type and equipment earthing. These tests are: + +- transverse/differential (conductor to conductor and pair to pair for power over Ethernet (PoE)); +- external port to earth; +- external port to external port; +- external port to internal port; + +NOTE 1 – This test is performed as part of the external port to earth test. + +- internal port to earth; +- internal port to internal port. + +NOTE 2 – This test is performed as part of the internal port to earth test. + +### 7.2.1 Transverse/differential + +A transverse or differential test should be performed on all external port types of the equipment. The test is performed with some untested ports of each port type terminated. + +### 7.2.2 External port to earth + +External port to earth tests should be performed on all equipment with external ports. This test is performed with all untested ports (both internal and external) terminated and then repeated with each type of internal port, earthed via a coupling element, in turn. + +### 7.2.3 External port to external port + +External port to external port tests should be performed on equipment with more than one external port. When the equipment is designed to be used with a connection to earth, the product Recommendation specifies when the test is to be performed. This test is performed with all untested ports (both internal and external) terminated, with each type of external port, including a port of the same type, earthed via a coupling element, in turn. + +It is necessary in external port to external port testing to consider the following as the second port: + +- 1) other lines/pairs of the port type being tested (e.g., pair 1 to pair 2 of port type 1); +- 2) lines/pairs of other port types (e.g., pair 1 of port type 1 to pair 1 of port type 2). + +An example of a test sequence is provided in Figure 7-1. Clause A.2 contains some examples of the different ports and test sequences. + +![Figure 7-1 shows two test schematics for an Equipment Under Test (EUT). The left schematic shows a rectangular EUT block with 'External port type 1' (a1, b1, a2, b2) on the left, 'External port type 2' (c1, d1, c2, d2) on the right, and 'Internal port type 1' (e1, f1) and 'Internal port type 2' (g1, h1) at the bottom. All ports are connected to a common ground point E. The right schematic shows a partial EUT with PoE ports labeled i1 through i8, also connected to a common ground point E. The label K.44(17)_F7-1 is in the bottom right.](9c6461e1e94afae4dec455e69a2ce152_img.jpg) + +Figure 7-1 shows two test schematics for an Equipment Under Test (EUT). The left schematic shows a rectangular EUT block with 'External port type 1' (a1, b1, a2, b2) on the left, 'External port type 2' (c1, d1, c2, d2) on the right, and 'Internal port type 1' (e1, f1) and 'Internal port type 2' (g1, h1) at the bottom. All ports are connected to a common ground point E. The right schematic shows a partial EUT with PoE ports labeled i1 through i8, also connected to a common ground point E. The label K.44(17)\_F7-1 is in the bottom right. + +Example test sequence + +a1 – b1 (transverse/differential test) + +a1/b1 – E (external port to earth test) + +a1/b1 – E with e1/f1 coupled to E (external port to earth test with one internal port coupled to ground) + +a1/b1 – c1/d1 with E disconnected (external port to external port test with one external port coupled to ground) + +e1/f1 – E (internal port to earth test) + +e1/f1 – E (internal port to earth test with one internal port coupled to ground) + +i1/i2/i3/i4/i5/i6/i7/i8 – E (PoE port to earth test) + +i1/i2/–i3/i6/ or i4/i5/ – i7/i8 (PoE transverse/differential powering pair to powering pair test) + +**Figure 7-1 – Example of a test sequence** + +### 7.2.4 Internal port to earth + +Internal port to earth tests are performed on all internal port types classified as an internal port (see clause A.2.1), unless excluded by the product Recommendation. This test is performed with some untested ports of each port type terminated and then with each type of internal port coupled to earth, in turn. + +## 7.3 Test conditions + +The following conditions apply to all the tests specified in clause 10. + +- 1) All tests are type tests and are tested under standard operating conditions unless otherwise specified in the product family or product Recommendation. +- 2) The ports at which tests on the equipment are to be applied should be identified by the manufacturer: + - $a$ and $b$ , $c$ and $d$ , $e$ and $f$ , etc., for different single symmetric pair ports; + - $a_1$ to $a_n$ and $b_1$ to $b_n$ , $c_1$ to $c_m$ and $d_1$ to $d_m$ , $e_1$ to $e_p$ and $f_1$ to $f_p$ , etc., for different multiple symmetric pair ports; + - inner and outer for coaxial cable ports; + - $dpf_1$ and $dpf_2$ , etc., for dedicated power feed ports; + - $L_1$ , $L_2$ , $L_3$ and $N$ for mains power ports; and + - E is used to designate that point on the equipment nominally connected to the safety earth. In some test configurations this point will not be connected to the safety earth. + +Parts labelled on the test schematics are: + +- generator return/Earth is used to designate a common reference point connected to safety earth. This connection to safety earth may in some cases be via the test generator; +- equipment under test (EUT) reference bar is used to designate a bonding bar for the EUT. + +- 3) Tests shall be performed with the equipment operating; the only exception to this is during the power contact test. If the power contact test is performed without the equipment being powered, it must not affect the test result. The equipment shall be tested in any operating state of significant duration, see clause A.2.4. To prove compliance, the equipment may need to be tested with both the tested and untested ports terminated and with untested ports coupled to earth, see clauses A.5 and clause 6.5.1 of [b-ITU-T K-Sup.17]. For Ethernet port testing, the equipment is surge tested in a powered condition, but not connected to a LAN. After surge and any insulation resistance testing, the tested equipment performance is verified with a LAN connected. +- 4) Terminations for the tested and untested ports include auxiliary equipment (AE), e.g., LI, LT, network termination (NT), CPE, a power supply (PS), a simulator or a passive termination. If it is not necessary to have the auxiliary equipment connected in order to verify that the EUT will resist the test voltage, the test may be performed without the auxiliary equipment connected. Where different terminations may occur, e.g., with or without primary protection, these terminations need to be considered, refer to clause 6.5.1 of [b-ITU-T K-Sup.17]. Decoupling elements are used to prevent the surge damaging the auxiliary equipment or termination. +- 5) Ports may need to be tested with a finite number of untested ports of the same and different types earthed in order to confirm that the equipment fulfils the specified acceptance criteria. Coupling elements are used to earth the appropriate port as required in conditions 7 and 8 below. +- 6) Transverse/differential tests shall be performed with at least one port of each type of port terminated, except for internal ports. +- 7) External port to earth tests shall be performed without coupling to earth on the untested ports and also with each type of internal port coupled to earth in turn. +- 8) External port to external port tests shall be performed with each type of external port, including a port of the same type, coupled to earth in turn. +- 9) Each test shall be applied the number of times indicated in the product family or product Recommendation. The polarity of lightning surge tests should be reversed between consecutive surges. The time interval between consecutive tests on the same port should be approximately one minute. The tests shall also be applied at longer time intervals, if necessary, to confirm that the equipment fulfils the specified acceptance criteria for surges which occur at intervals exceeding one minute. An example of this is to confirm that the equipment passes when all surges are applied to positive temperature coefficient thermistors (PTCs) at normal operating temperature. +- 10) When the transverse/differential test is applied between two terminals, one of the terminals shall be connected to the surge generator and the other terminal shall be connected to earth. The test shall then be repeated with the terminals transposed. +- 11) Power induction tests should be made at the frequencies of the electric power system or the electrified railway systems used in the country of application. +- 12) In all cases where a maximum voltage, current or $I^2t$ is specified, tests shall also be made at lower values to confirm that the equipment fulfils the specified acceptance criteria for any voltage, current or $I^2t$ up to the maximum value specified. Confirming that the equipment complies with the requirements at voltages less than $U_{c(max)}$ can be performed using either of the two methods described below: + - using knowledge of the protection elements. Clause 6 of [b-ITU-T K-Sup.17] gives an example of how to perform lightning and power induction tests at specific test points to ensure that the equipment complies with the requirements of the product Recommendation. Where the tests are only performed at maximum values, the reason + +shall be given in the test report, e.g., the equipment does not contain switching type secondary protectors; + +- using set test levels as described in [b-IEC 61643-21]. If this method is used, tests shall be performed at 20%, 30%, 45%, 60%, 75%, 90% and 100% of $U_{c(\max)}$ ; +- where product Recommendations allow reduced testing, e.g., power contact tests, as many tests as necessary shall be performed in order to confirm that the equipment fulfils the specified acceptance criteria. + +NOTE – Particular components which need to be considered during testing include the primary protector, switching or foldback type inherent protectors, PTCs and fuses. + +Where fuse resistors are used, tests shall be applied at a range of test levels to ensure that the worst case is tested. + +- 13) A new primary protection component (special test protector (STP) or agreed primary protector) may be used if degradation of the protector is thought to, or known to, have occurred. +- 14) Where components may have significant variations in characteristics which can affect the resistibility level of the equipment, e.g., PTCs where their cold resistance could vary from, for example, 2-7 $\Omega$ , tests should be performed on equipment using the worst-case component or by using any other method which achieves the aim. A worst-case component is one which causes the equipment to have the lowest resistibility level. +- 15) Cards shall be tested in one or more slots as is necessary to confirm that the equipment fulfils the specified acceptance criteria. +- 16) If a card has two or more identical ports, only one of these needs to be tested in single port tests. + +## 7.4 Test schematics + +Refer to Annex A. + +# 8 Protection coordination + +## 8.1 General + +For equipment installed in a more exposed environment, it is current practice to protect ports, connected to external metallic conductors, with primary protectors such as gas discharge tubes (GDTs), solid state arresters (SSAs) or metal oxide varistors (MOVs). The best place for the insertion of the primary protection is the border of the building, shelter or equipment housing. This is not always possible but every attempt should be made to place the primary protection as close as possible to the entry point of the cables into the building, shelter or equipment housing. The characteristics of these primary surge protective devices (SPDs) shall comply with the requirements of [ITU-T K.12], [ITU-T K.28] or [IEC 61643-12]. + +Primary protection coordination is required to ensure compatibility of the equipment with the primary protection. Coordination testing should be done with an agreed primary protector. Ethernet primary protection relying on an isolating transformer to block longitudinal/common mode voltage surges does not divert current to earth like SPDs. This type of Ethernet protector is best placed close to the port it is protecting. + +## 8.2 Lightning + +To achieve coordination for protection against lightning surges, the following must occur: + +- the inherent protection within the equipment must provide protection up to the voltage at which the agreed primary protection operates for generator voltages less than the $U_{c(\max)}$ specified in the product family or product Recommendation; +- between this voltage and a generator voltage of $U_{c(\max)}$ , the primary protection must operate and protect the equipment; +- the equipment must comply with the specified criterion of the product family or product Recommendation; +- the lightning-surge coordination tests use a special test protector (see clause 8.4), instead of the primary protector, to allow the use of a safety factor during the tests. This safety factor includes: the maximum primary protector voltage, tolerances on equipment components, the number of test samples and the effect of multiple impulses. At a generator voltage setting equal to the $U_{c(\max)}$ of the product family or product Recommendation, the special test protector must operate. The special test protector may of course also operate at values less than $U_{c(\max)}$ ; +- Ethernet primary protection reliant on an isolating transformer to block longitudinal/common mode voltage surges should have a rated impulse voltage greater than the highest expected surge voltage. Such a protection arrangement does not necessarily have an impulse voltage withstand equal to the summation of the port and protector withstands as explained in clause 6.7.5 of [b-ITU-T K-Sup.18]. + +### 8.2.1 Primary SPDs with a switching characteristic + +Coordination is achieved with a switching type SPD when the special test protector (see clause 8.4.1) is activated with a $U_c$ below the maximum level specified in the relevant product family or product Recommendation, for testing with agreed primary protection, and the equipment complies with the specified criterion of that Recommendation. + +### 8.2.2 Primary SPDs with a clamping characteristic + +Coordination with a clamping type SPD is achieved when the equipment complies with specified criterion of the product Recommendation when tested with the special test protector (see clause 8.4.2), when tested at the maximum test voltage and current of the coordination test, i.e., when the primary SPD is conducting maximum current. + +## 8.3 Power induction, earth potential rise and power contact + +Protection against power induction and EPR, as a result of a power fault to earth, is achieved by the inherent protection or a combination of the inherent protection and the agreed primary protection. + +Protection against power contact must be achieved by the inherent protection unless the equipment is designed to always be used with primary protection. In this case protection is provided by a combination of the inherent protection and the agreed primary protection. + +The input impedance to earth of both the a and b inputs of some equipment may be low when the inherent overvoltage protection is activated. In this case, the voltage across the impedance to earth, caused by the current that flows during power induction or EPR, may be too low to activate the primary protection. If the primary protection is not activated, internal heating may damage the equipment. + +Testing should be done at a.c. levels that result in overvoltage protector voltages being just below their limiting voltage threshold. These conditions on primary and on any secondary protectors should maximize the equipment power dissipation and temperature rise. + +## 8.4 Special test protector + +The special test protector shall have similar behaviour to that of the agreed primary protector. + +### **8.4.1 Switching type protector** + +The d.c. operating voltage of the special test protector shall be equal to 1.15 times the specified maximum d.c. operating voltage, after life test value, of the agreed primary protector. The tolerance of this firing voltage is $\pm 5\%$ . It should also have a similar impulse to d.c. operating ratio as the agreed primary protector. The manufacturer may use a special test protector with a higher operating voltage. + +### **8.4.2 Clamping type protector** + +The clamping voltage of the special test protector shall be equal to 1.15 times the specified maximum clamping voltage of the agreed primary protector. The tolerance of this clamping voltage is $\pm 5\%$ . The manufacturer may use a special test protector with a higher operating voltage. + +### **8.4.3 Multistage modules** + +When the primary protection is a multistage module, replace the primary protection with a special test module which uses components according to clauses 8.4.1 and 8.4.2. + +## **8.5 Selection of the agreed primary protector** + +A test house or laboratory needs to be given the characteristics of the "agreed" primary protector for the equipment under test so that they can select the special test protector. Information on how to select the "agreed" primary protector for GDTs is contained in [ITU-T K.12]. + +# **9 Acceptance criteria** + +Two acceptance criteria are recognized: + +- 1) Criterion A – The equipment shall withstand the test without damage and shall operate within the manufacturer's specified performance limits after the test without an operator or user having to repower the equipment, perform a software or hardware reset or remove printed circuit cards. The test shall not affect the continuous operation of other hardware and software parts of the equipment, but a temporary degradation of performance is allowed. However, users may need to reinitiate a service, e.g., remake a call or restart a download. It should be ensured that all components of the equipment (e.g., ports, processor unit, display, wireless local area network (WLAN)) will continue to operate without any constraints after the surge. The operation of overcurrent protection may temporarily disable the operation of some ports. The service may not become immediately available straight after the protection resets, for example, retraining may need to occur. It is expected that all ports should recover to normal functionality within a reasonable amount of time, from the cessation of the test, and documented by the equipment manufacturer. + +If the power contact test is performed without the equipment being powered, it must not affect the test result. After the test, the system shall operate within the specified performance limits. + +- 2) Criterion B – The equipment may be damaged, but tests must not result in a safety hazard; in particular: + - if a flame occurs, it shall not propagate beyond the equipment; and + - the equipment shall not emit hot materials, e.g., molten metals. + +A cheesecloth indicator may be used. In this case, the test shall not damage the structural integrity of the cheesecloth by ignition, charring, forceful ejection of fragments or melted materials into it. + +# **10 Tests** + +The test generators, test circuits, coupling and decoupling elements and port terminations are provided in Annex A. + +Certain considerations which justify the test proposals are stated in [b-ITU-T K-Sup.17]. The response of equipment to surges may be modified by the input impedance of the equipment. To explain this effect, [b-ITU-T K-Sup.17] includes an example circuit and instantaneous levels of voltage at different points in the circuit to show the effect of input impedance. These values are included for illustration only and do not form any part of this Recommendation. + +The port types shown in Table 1 are considered. Remote feed telecommunication circuits share the same port as the signal port. + +Depending on the equipment, the PoE port either sources power or receives power. 10/100/1000 Base T may use the spare pairs or the signal pairs. + +Specific ITU-T K Recommendations may exempt internal port surge testing where the interconnecting cable is not longer than a defined maximum value, e.g., 10 m. + +No surge tests are applied to internal ports with cables that are not permanently connected according to the manufacturer's specifications, e.g., maintenance ports. + +**Table 1 – Port types** + +| Port type | | Test type | Example | +|-----------|-----------------------------------|-------------------------------------------------|--------------------------------------------------------------------------------------------------| +| External | Symmetric pair | Lightning | Analogue customer interface | +| | | Power induction and earth potential rise | Integrated services digital network (ISDN) basic-rate interface
Remote power feeding circuits | +| | | Mains power contact | xDSL interface | +| | Coaxial cable | Lightning | ISDN primary-rate interface | +| | | Power induction and earth potential rise | Remote power feeding circuits | +| | Dedicated power feed (a.c., d.c.) | Lightning | Optical network unit/termination power feed interface | +| | | Power induction and earth potential rise | | +| | a.c. mains power | Lightning | a.c. mains power | +| | | Earth potential rise and neutral potential rise | | +| | Internal | Lightning | | +| | | Shielded cable (including coaxial cable) | | +| | | d.c. power interface | | + +Ethernet port pairs have common components in the "Smith" termination network and adaptive functionality depending on the LAN data rate. Ethernet ports are tested with the surge being applied simultaneously to all pairs. PoE ports are a special case and have a unique transverse/differential test where the surge is applied to the feed and return powering pairs. + +A summary of the applicable tests is given in Table 2. The numbers given in the "port type" columns, e.g., 10.1.2, refer to the appropriate clause number in this Recommendation which discusses this test. The letters "n/a" mean the test is not applicable. The words "under study" mean that ITU-T is still studying this test. + +The terms "transverse/differential", "port to earth" or "port to external port" refer to whether the surge is applied transversely/differentially (i.e., line to line, line to shield, or in differential mode), port to earth (line to earth or in common mode) or port to external port (port to port with the earth reference floating). + +The terms "single" and "multiple" refer to the number of pairs tested. For a test on an external or internal port with a single pair (single pair port), the surge test is applied on that pair (refer to Figure A.2-6). + +If there are different external ports of the same type, the surge test (lightning only) is then repeated on the specified number of pairs of that port type simultaneously, refer to Figure A.2-6. + +For a test on an external port with multiple pairs (a multiple-pairs port), the surge test is applied on each pair as for a test on a single pair port, refer to Figure A.2-7. + +Then the surge test (lightning only) is repeated on the specified number of pairs of that port simultaneously, refer to Figure A.2-7. + +For a test on a product with external ports that consist of different interface types, each connected to a single pair or multiple pairs, the surge test is applied on each pair as for a test on a single pair port, refer to Figure A.2-8. + +Then the surge test (lightning only) is repeated on the specified number of pairs simultaneously, refer to Figure A.2-8. + +For surge tests on an internal port with a single pair or multiple pairs, the surge test (lightning only) is applied to all pairs of that port simultaneously, refer to Figure A.2-9. + +More information and examples are given in clause A.2. + +**Table 2a – Applicable tests for external ports** + +| Test type | Number of pairs simultaneously tested | Test mode | Primary protection | Port type | | | | +|-------------------|---------------------------------------|-------------------------|--------------------|----------------|--------------|---------------------------|------------------| +| | | | | Symmetric port | Coaxial port | Dedicated power feed port | Mains power port | +| Lightning voltage | Single | Transverse/differential | No | 10.1.1.1 | 10.2.1 | 10.3.1 | 10.4.1 | +| | | Port to earth | No | 10.1.1.1 | n/a | 10.3.1 | 10.4.1 | +| | | Port to external port | No | 10.1.1.1 | n/a | 10.3.1 | 10.4.1 | +| | | Transverse/differential | Yes | 10.1.1.1 | 10.2.1 | 10.3.1 | 10.4.1 | +| | | Port to earth | Yes | 10.1.1.1 | n/a | 10.3.1 | 10.4.1 | +| | | Port to external port | Yes | 10.1.1.1 | n/a | 10.3.1 | 10.4.1 | +| | Multiple | Port to earth | No | 10.1.1.2 | n/a | n/a | n/a | +| | | Port to external port | No | 10.1.1.2 | n/a | n/a | n/a | +| | | Port to earth | Yes | 10.1.1.2 | n/a | n/a | n/a | +| | | Port to external port | Yes | 10.1.1.2 | n/a | n/a | n/a | +| Lightning current | Single | Transverse/differential | No | n/a | 10.2.2 | n/a | n/a | +| | | Port to earth | No | 10.1.2 | n.a | 10.3.2 | n/a | +| | | Port to external port | No | 10.1.2 | n.a | 10.3.2 | n/a | +| | | Transverse/differential | Yes | n/a | 10.2.2 | n/a | n/a | +| | | Port to earth/shield | Yes | n/a | 10.2.3 | n/a | n/a | + +**Table 2a – Applicable tests for external ports** + +| Test type | Number of pairs simultaneously tested | Test mode | Primary protection | Port type | | | | +|---------------------------------------------|---------------------------------------|------------------------------|--------------------|----------------|--------------|---------------------------|-----------------------| +| | | | | Symmetric port | Coaxial port | Dedicated power feed port | Mains power port | +| Power induction and/or earth potential rise | Multiple | Port to external port/shield | Yes | n/a | 10.2.3 | n/a | n/a | +| | | Port to earth | No | 10.1.2 | n.a | n/a | n/a | +| | Single | Port to external port | No | 10.1.2 | n.a | n/a | n/a | +| | | Transverse/differential | No | 10.1.3 | 10.2.4 | 10.3.3 | n/a | +| Power induction and/or earth potential rise | Single | Port to earth | No | 10.1.3 | n/a | 10.3.3 | 10.4.2
Under study | +| | | Port to external port | No | 10.1.3 | n/a | 10.3.3 | 10.4.2
Under study | +| | | Transverse/differential | Yes | 10.1.3 | 10.2.4 | 10.3.3 | n/a | +| Neutral potential rise | Single | Port to earth | Yes | 10.1.3 | n/a | 10.3.3 | Under study | +| | | Port to external port | Yes | 10.1.3 | n/a | 10.3.3 | Under study | +| Mains power contact | Single | Port to earth | No | n/a | n/a | n/a | 10.4.3 | +| | | Port to external port | No | n/a | n/a | n/a | 10.4.3 | + +**Table 2b – Applicable tests for internal ports (Specific K Recommendations may exempt port testing based on interconnecting cable length)** + +| Test type | Primary protection | Port type | | | | +|-------------------|--------------------|------------------|----------------|-----------------------------|-----------------------------------| +| | | Unshielded cable | Shielded cable | Floating DC power interface | Earthed bonded DC power interface | +| Lightning voltage | No | 10.5.1 | 10.5.2 | 10.5.3 | 10.5.4 | + +## **10.1 External symmetric pair port** + +### **10.1.1 Lightning voltage** + +For equipment with high current-carrying protection components, which eliminates the need for primary protection, the following applies: + +- if this component is removable, an exception to clause 6 applies and it shall be removed and replaced by the special test protector for the coordination tests, see clause 8.4; +- if this component is not removable, all tests are performed with the protection provided and the manufacturer must provide a test report to show that the coordination tests were performed with the special test protector during the design tests. + +#### **10.1.1.1 Single pair** + +The single port lightning test checks that each port of the equipment has the required level of overvoltage resistibility. Transverse/differential, port to earth, and port to external port tests shall be performed. PoE ports, which combine signal and power, have the transverse/differential test applied to the feed and return powering pairs. + +#### **10.1.1.2 Multiple pairs/ports** + +The multiple pairs/ports lightning surge test checks that the equipment has the required level of resistibility when an overvoltage surge occurs on $n$ pairs or ports simultaneously, which can result in a high current flowing into a common component or part of the equipment. + +The number or percentage of pairs or ports to be tested simultaneously is specified in the product family or product Recommendation. + +Both port to earth and port to external port tests shall be performed. + +Care should be taken in the case where the equipment does not have SPDs to earth. The voltage at the equipment input should not be allowed to exceed the single port test $U_{c(\max)}$ . + +### **10.1.2 Lightning current** + +The overcurrent test checks that the equipment has the required level of inherent resistibility when high current-carrying protection components are installed within the equipment to eliminate the need for primary protection. This test checks the coordination of high current protectors, integral to the equipment, with connectors and printed circuits tracks, etc. The overcurrent test is specified in the product family or product Recommendation. + +When applying the test to multiple wires, care should be taken to ensure that the current is divided equally between the wires. Particular care should be taken to ensure that the operation of one or more protectors does not prevent the operation of the other protectors. + +Both port to earth and port to external port tests shall be performed. + +### **10.1.3 Power induction and earth potential rise** + +Transverse/differential, port to earth, and port to external port tests shall be performed. + +If the equipment port has inherent primary protection, which eliminates the need for primary protection, the following applies: + +- if the inherent primary protection is integrated primary protection, an exception to clause 6 applies and the primary protection SPD shall be removed and replaced by the special test protector for both the inherent and coordination tests, see clause 8.4; +- if the inherent primary protection is embedded primary protection, all tests are performed with the protection provided. In addition, the manufacturer must provide a test report to show + +that inherent and coordination type testing was performed with high current-carrying protection components having the minimum specified power frequency limiting voltage. + +### **10.1.4 Mains power contact tests** + +Transverse/differential, port to earth, and port to external port tests shall be performed. If the equipment port has inherent primary protection, which eliminates the need for primary protection, the following applies: + +- perform the test with the protection as supplied by the manufacturer. Ensure that the protection operates during the test. This may require selecting a line with a protector which has a low limiting voltage. It is not necessary to confirm protector operation if one or more of the following apply: + - the equipment manufacturer, during the equipment design, has chosen the protector firing voltage so that the protector will not operate for power contact; + - the equipment input impedance prevents the power contact voltage, at the input of the equipment, from exceeding the specified minimum limiting voltage of the protector type. +- if the inherent primary protection is integrated primary protection, an exception to clause 6 applies and the primary protection SPD shall be removed and replaced by the special test protector for both the inherent and coordination tests, see clause 8.4; +- if the inherent primary protection is embedded primary protection, all tests are performed with the protection provided. In addition, the manufacturer must provide a test report to show that inherent and coordination type testing was performed with high current-carrying protection components having the minimum specified power frequency limiting voltage. + +## **10.2 External coaxial port** + +### **10.2.1 Lightning voltage** + +The lightning voltage test is applied in differential mode. + +For equipment with high current-carrying protection components, which eliminates the need for primary protection, the following applies: + +- if this component is removable, an exception to clause 6 applies and it shall be removed and replaced by the special test protector for both the inherent and coordination tests, see clause 8.4; +- if this component is not removable, all tests are performed with the protection provided and the manufacturer must provide a test report to show that the inherent and coordination tests were performed with the special test protector during the design tests. + +The lightning test checks that the port of the equipment has the required level of overvoltage resistibility. The tests are applied to the inner conductor. The equipment is tested as installed in the field, e.g., if any components are normally connected between the port and the surge protector, these components should be in place during the surge testing. + +### **10.2.2 Lightning current differential** + +The lightning current test is applied in differential mode. + +The overcurrent test checks that the equipment has the required level of inherent resistibility when high current-carrying protection components are installed within the equipment to eliminate the need for primary protection. This test checks the coordination of high current protectors, integral to the equipment, with connectors and printed circuits tracks, etc. The overcurrent test is specified in the product family or product Recommendation. + +### **10.2.3 Lightning current shield test** + +The lightning current test is applied to the shield. + +The overcurrent test checks that the connection of the shield to the frame/earth of the equipment is adequate to conduct the high levels of surge current which may occur in the field. The overcurrent test is specified in the product family or product Recommendation. + +Both port to earth and port to external port tests shall be performed. + +### **10.2.4 Earth potential rise** + +The earth potential rise test is applied in differential mode. + +If the equipment has high current-carrying protection components, which eliminates the need for primary protection, the following applies: + +- if this component is removable, an exception to clause 6 applies and it shall be removed and replaced by the special test protector for both the inherent and coordination tests, see clause 8.4; +- if this component is not removable, all tests are performed with the protection provided and the manufacturer must provide a test report to show that the inherent and coordination tests were performed with the special test protector during the design tests. + +## **10.3 External d.c. and a.c. dedicated power feeding ports** + +### **10.3.1 Lightning voltage** + +The lightning test is used to check that each port of the equipment has the required level of overvoltage resistibility. Transverse/differential, port to earth, and port to external port tests shall be performed. + +For equipment with high current-carrying protection components, which eliminates the need for primary protection, the following applies: + +- if this component is removable, an exception to clause 6 applies and it shall be removed and replaced by the special test protector for both the inherent and coordination tests, see clause 8.4; +- if this component is not removable, all tests are performed with the protection provided and the manufacturer must provide a test report to show that the inherent and coordination tests were performed with the special test protector during the design tests. + +### **10.3.2 Lightning current** + +The overcurrent test checks that the equipment has the required level of inherent resistibility when high current-carrying protection components are installed within the equipment to eliminate the need for primary protection. This test checks the coordination of high current protectors integral to the equipment, with connectors and printed circuits tracks, etc. The overcurrent test is specified in the product family or product Recommendation. Both port to earth and port to external ports tests shall be performed. + +### **10.3.3 Power induction and earth potential rise** + +Transverse/differential, port to earth, and port to external port tests shall be performed. + +If the equipment has high current-carrying protection components, which eliminates the need for primary protection, the following applies: + +- if this component is removable, an exception to clause 6 applies and it shall be removed and replaced by the special test protector for both the inherent and coordination tests, see clause 8.4; + +- if this component is not removable, all tests are performed with the protection provided and the manufacturer must provide a test report to show that the inherent and coordination tests were performed with the special test protector during the design tests. + +### **10.3.4 Mains power contact** + +Transverse/differential, port to earth, and port to external port tests shall be performed. If the equipment has high current-carrying protection components, which eliminates the need for primary protection, the following applies: + +- perform the test with the protection as supplied by the manufacturer. Ensure that the protection operates during the test. This may require selecting a line with a protector which has a low firing voltage. It is not necessary to confirm protector operation if one or more of the following apply: + - the equipment manufacturer, during the equipment design, has chosen the protector firing voltage so that the protector will not operate for power contact; + - the equipment input impedance prevents the power contact voltage, at the input of the equipment, from exceeding the specified minimum firing voltage of the protector type. +- if this component is removable, an exception to clause 6 (equipment boundary) applies and it shall be removed and replaced by the special test protector (see clause 8.4) and the tests repeated. + +If this component is not removable, the manufacturer must provide a test report to show that the tests were repeated with a protector with a firing voltage equal to the specified minimum d.c. firing voltage during the design tests. + +## **10.4 External a.c. mains power port** + +### **10.4.1 Lightning voltage** + +Transverse/differential, port to earth, and port to external port tests shall be performed. + +Three types of primary protector SPDs are known to exist for use on the electricity supply mains, and these are: + +- 1) clamping (MOV) type; +- 2) switching (spark gap); +- 3) a combination of both. + +Because of the different characteristics of these SPDs, a manufacturer may need to check that this equipment coordinates with all three types. + +### **10.4.2 Earth potential rise** + +ITU-T is studying the need for a test to check resistibility of the equipment from the earth potential rise, which can occur when a high voltage (HV) earth fault occurs on the substation providing mains power to the equipment. + +### **10.4.3 Neutral potential rise** + +This test applies only on the request of the network operator, and when the neutral is not connected to the protective earth (i.e., a TT or IT mains system). An example of such a configuration is described in clause 6.5 of [b-ITU-T K-Sup.18]. + +## **10.5 Internal ports** + +### **10.5.1 Unshielded cable** + +The lightning voltage test is to check that the equipment port has the required level of overvoltage resistibility. Only a port to earth test is performed. + +### **10.5.2 Shielded cable** + +The lightning voltage test is to check that the equipment port has the required level of overvoltage resistibility. Only a port to earth test is performed. + +### **10.5.3 Floating DC power interface** + +The lightning voltage test is to check that the equipment port has the required level of overvoltage resistibility. Only a port to earth test is performed. + +### **10.5.4 Earthed bonded DC power interface** + +The lightning voltage test is to check that the equipment port has the required level of overvoltage resistibility. Only a transverse/differential-mode surge test is performed. + +## **10.6 Intra-system ports** + +Intra-system ports within a telecommunication centre equipment (TCE) are expected to be interconnected by short cables or shielded cables under the control of the manufacturer. Hence, there is a low possibility that overvoltage is induced directly on that cables. However, intra-system ports are exposed to the overvoltage that gets in from other external or internal ports. + +From this, by deeming equipment interconnected via intra-system ports as a "combined equipment" and performing the resistibility tests specified for its other external and internal ports, which apply overvoltage to them, the resistibility of its intra-system ports can be considered as compliant, as shown in Figure 10-1. + +Therefore, in the case that a manufacturer specifies the dedicated and combined use of multiple equipment as a combined equipment and specifies the cables for this interconnection, which cables shall be short or shielded (cable screen or cable trays, etc.), the ports for this interconnection may be regarded as "intra-system ports". Requirements for intra-system ports have not been specified. + +The description above cannot apply to the equipment which may be used as in connection configurations other than that the manufacturer specifies. The ports of a combined equipment connected to other equipment need to perform the specified tests. + +![Diagram showing two pieces of equipment (Equipment 1 and Equipment 2) within a dashed boundary representing a combined equipment. Yellow arrows represent surge paths entering from external ports on both sides, passing through the equipment, and going to ground. Intra-system ports connect the two pieces of equipment internally. Text labels describe the ports and the application of surge tests.](7ae836e598020d937ed1478c2ef13025_img.jpg) + +A combined equipment + (dedicated use of multiple telecommunication centre equipment specified by their manufacturer) + +Ports connected to other equipment (need to perform specified tests) + +Ports connected to other equipment (need to perform specified tests) + +Equipment 1 + +Equipment 2 + +Surge etc. applied for resistibility test + +Surge etc. applied for resistibility test + +Intra-system ports (interconnected by short or shielded cables manufacturer-specified); +their resistibility can be considered as it is confirmed by performing resistibility tests +for other external and internal ports + +K.44(18)\_F10-1 + +Diagram showing two pieces of equipment (Equipment 1 and Equipment 2) within a dashed boundary representing a combined equipment. Yellow arrows represent surge paths entering from external ports on both sides, passing through the equipment, and going to ground. Intra-system ports connect the two pieces of equipment internally. Text labels describe the ports and the application of surge tests. + +**Figure 10-1 – Intra-system ports are not tested directly, but by surging the available system internal and external ports** + +# Annex A + +## Test schematics + +(This annex forms an integral part of this Recommendation.) + +## A.1 Introduction + +Equipment needs to be tested in all likely states and conditions. This means that the test specified in each line of the test table may need to be performed many times. + +To ensure repeatability of testing by test houses and manufacturers, it is necessary to ensure that the tests are performed in the same way. Below are the generator circuits, coupling, decoupling and powering circuits, the termination of untested ports, and the connection to the EUT. + +## A.2 Equipment + +### A.2.1 Equipment ports + +Multiple port is the term used to describe equipment with more than one type of port, e.g., a mains port and an external symmetric pair port. Figure A.2-1 shows the possible ports of a piece of equipment with multiple ports. + +![Diagram of multiple port equipment showing external and internal ports connected to an EUT.](b2ddf2a678bd20b1b491023eb1db6458_img.jpg) + +The diagram illustrates a central rectangular block labeled 'EUT' (Equipment Under Test). A vertical dashed line bisects the block. Above the block, the left side is labeled 'External ports' and the right side is labeled 'Internal ports'. On the left, four horizontal lines extend from the EUT block, each labeled with a port type: 'Symmetric pair(s)', 'Coaxial', 'Mains power', and 'Dedicated power feed'. On the right, five horizontal lines extend from the EUT block, labeled with port types: 'Symmetric pair(s)', 'Coaxial', 'Power', 'Auxiliary, e.g., USB, serial/parallel', and an unlabeled line at the bottom. The label 'K.44(17)\_FA.2-1' is located in the bottom right corner of the diagram area. + +Diagram of multiple port equipment showing external and internal ports connected to an EUT. + +NOTE 1 – Not all ports need to be tested but they may need to be terminated. + +NOTE 2 – "External ports" means ports connected to cables which exit the building and "Internal ports" means ports connected to cables which remain within the building. + +**Figure A.2-1 – Multiple port equipment** + +Figure A.2-2 shows the classification of ports of equipment. + +![Diagram illustrating the classification of external and internal ports in a telecommunications network. It shows an Exchange building connected to a Remote site and two Customer buildings. The Exchange building contains Telecom equipment connected via intra-building signal lines (M, L) and outdoor signal lines (E). A Primary protector (where used) is connected to the outdoor signal line. The Remote site contains Equipment connected via signal lines (R). Customer building 1 and Customer building 2 contain Telecom equipment connected via outdoor signal lines (S, A) and intra-building signal lines (I). PE conductors and SPD-MET bonds are shown for grounding.](e451401f8fa77b466f401d5fce15b26c_img.jpg) + +The diagram illustrates the classification of external and internal ports in a telecommunications network. It shows an Exchange building connected to a Remote site and two Customer buildings. The Exchange building contains Telecom equipment connected via intra-building signal lines (M, L) and outdoor signal lines (E). A Primary protector (where used) is connected to the outdoor signal line. The Remote site contains Equipment connected via signal lines (R). Customer building 1 and Customer building 2 contain Telecom equipment connected via outdoor signal lines (S, A) and intra-building signal lines (I). PE conductors and SPD-MET bonds are shown for grounding. + +Diagram illustrating the classification of external and internal ports in a telecommunications network. It shows an Exchange building connected to a Remote site and two Customer buildings. The Exchange building contains Telecom equipment connected via intra-building signal lines (M, L) and outdoor signal lines (E). A Primary protector (where used) is connected to the outdoor signal line. The Remote site contains Equipment connected via signal lines (R). Customer building 1 and Customer building 2 contain Telecom equipment connected via outdoor signal lines (S, A) and intra-building signal lines (I). PE conductors and SPD-MET bonds are shown for grounding. + +**Figure A.2-2 – Classification of external and internal ports** + +Table A.2-1 provides a description of the nodes. + +**Table A.2-1 – Description of nodes** + +| Node | Description | +|------|-------------------------------------------------------------------------------------------------| +| L | Transition between equipment interface inside the exchange building and the external cabling. | +| E | Entrance of the exchange building, e.g., main distribution frame (MDF). | +| R | Transition between line and equipment inside a remote site. | +| S | External cable termination point (ECTP). | +| A | Transition between equipment interface inside the customer's building and the external cabling. | +| M | Transition between equipment interface inside the exchange's building and the internal cabling. | +| I | Transition between equipment interface inside the customer's building and the internal cabling. | + +It is necessary to consider the differences between external ports, internal ports and intra-system ports. + +An equipment port can only be classified as an intra-system port if both of the following apply: + +- the port is cabled to an intra equipment port of the same system; and +- the cabling is installed according to the equipment manufacturer's directions. + +An equipment port can only be classified as an internal port if all of the following apply: + +- it is only connected to intra-building cables; +- the cable is connected to an internal port of the associated equipment; + +- the equipment and the associated equipment have the same earth reference or the equipment is floating; +- the port will not be connected to an external port of the associated equipment; +- the port is designated by the equipment manufacture to be only suitable for intra-building cable connection; +- the port will not have a conductive connection to a cable which leaves the building via other equipment (e.g., via a splitter). + +Any port not complying with the requirements for an intra-building system port or an internal port is an external port. + +Figure A.2-3 is an example of port classifications. + +![Diagram illustrating port classifications for VDSL equipment. A VDSL VTU-O is connected to an optical fibre cable and an outdoor signal line via a splitter. The splitter has two 'Ext.' ports labeled 'A'. The VTU-O has an 'Ext.' port. The outdoor signal line continues inside the building because the splitter lacks adequate isolation. Inside the building, the signal line connects to a VDSL VTU-R via another splitter with two 'Ext.' ports labeled 'A'. The VTU-R has an 'Ext.' port and an 'I' (intra-building) port. The 'I' port is connected to a PC via an 'Intra-building signal line' (labeled 'USB; Int. Ethernet; Ext.') and another 'I' port. The PC has an 'Ext.' port. The VTU-R also has an 'A' port connected to a Tel/Fax device via an 'Ext.' port labeled 'A'. The Tel/Fax has an 'Ext.' port. A note at the bottom states: 'Outdoor signal line continued inside the building as the splitter does not contain "adequate" isolation'. A reference code 'K.44(17)_FA.2-3' is in the bottom right.](78ff716475b2f65bf01c3a4d02d89fc4_img.jpg) + +Diagram illustrating port classifications for VDSL equipment. A VDSL VTU-O is connected to an optical fibre cable and an outdoor signal line via a splitter. The splitter has two 'Ext.' ports labeled 'A'. The VTU-O has an 'Ext.' port. The outdoor signal line continues inside the building because the splitter lacks adequate isolation. Inside the building, the signal line connects to a VDSL VTU-R via another splitter with two 'Ext.' ports labeled 'A'. The VTU-R has an 'Ext.' port and an 'I' (intra-building) port. The 'I' port is connected to a PC via an 'Intra-building signal line' (labeled 'USB; Int. Ethernet; Ext.') and another 'I' port. The PC has an 'Ext.' port. The VTU-R also has an 'A' port connected to a Tel/Fax device via an 'Ext.' port labeled 'A'. The Tel/Fax has an 'Ext.' port. A note at the bottom states: 'Outdoor signal line continued inside the building as the splitter does not contain "adequate" isolation'. A reference code 'K.44(17)\_FA.2-3' is in the bottom right. + +**Figure A.2-3 – Example of port classifications** + +Antenna ports on equipment need to be classified according to the location of the antenna and the intended use of the equipment. Where the equipment will only be connected to antennas installed in an inherently protected location, i.e., the shaded area in Figure A.2-4, the antenna port could be classified as an internal port. The complete antenna and all antenna cables have to fit and to be installed into the protected area. If the port could be connected to antennas installed in exposed locations, e.g., antenna positions 1 and 2, the antenna port should be classified as an external port. If it is unclear where the antenna may be installed, it is best to be conservative and classify the antenna port as an external port. + +![Diagram illustrating the classification of antenna ports based on lightning protection zones. Port 1 is an external antenna on a mast. Port 2 is an antenna on a roof with a height difference of > 2 m between the antenna and the roof edge. Port 3 is an antenna on a wall with a height difference of > 2 m from the roof edge and a distance of < 1.5 m from the wall. A red vertical line indicates a distance of < 50 m from the mast. The interior of the building is labeled 'Earthing not required'. The diagram is labeled K.44(17)_FA.2-4.](e64c7b989e5bdb2708cd7aefd18b06e1_img.jpg) + +Diagram illustrating the classification of antenna ports based on lightning protection zones. Port 1 is an external antenna on a mast. Port 2 is an antenna on a roof with a height difference of > 2 m between the antenna and the roof edge. Port 3 is an antenna on a wall with a height difference of > 2 m from the roof edge and a distance of < 1.5 m from the wall. A red vertical line indicates a distance of < 50 m from the mast. The interior of the building is labeled 'Earthing not required'. The diagram is labeled K.44(17)\_FA.2-4. + +**Figure A.2-4 – Classification of antenna ports** + +Symmetric pair ports may have a single pair or multiple pairs. Equipment may have multiple ports of the same or a different type. + +Ports may connect to paired cables, unscreened cables or screened cables including coaxial cables and may connect to different service types including an a.c. port, ADSL port, single-pair high-speed digital subscriber line (SHDSL) port and Ethernet port, etc. + +Examples of the different ports are shown in Figures A.2-5 to A.2-9. + +The port types above also have a structure and these are: + +- port type: A port that is connected to an interface with a specific function. The connection can consist of a single pair, multiple pairs, one or more coaxial or shielded cables, etc., e.g., a.c. port, ADSL port, SHDSL port, Ethernet port; +- single pair port: A port of a specific type connected to one single symmetric pair, e.g., ADSL port; +- multiple pairs port: A port of a specific type where that port is connected to multiple pairs, e.g., SHDSL with one TX pair and one RX pair, Gbit Ethernet port with 4 TX/RX pairs; +- multiple pair ports: Ports of different port types where each port is connected to one single pair or multiple pairs, e.g., a number of ADSL ports, a number of SHDSL ports. + +#### **Definitions** + +![Figure A.2-5 – Examples of equipment ports. The figure shows seven examples of equipment port configurations. Example 1 shows a variety of port types: ADSL1, ADSL2, SHDSL (TX/RX), AC, USB, Ethernet1 (TX/RX), and Ethernet2 (TX/RX). Examples 2 and 3 show single pair ports for ADSL1 and ADSL2 respectively. Example 4 shows a multiple pairs port for SHDSL. Examples 5 and 6 show multiple pairs ports for Ethernet1 and Ethernet2 respectively. Example 7 shows a combination of multiple pair ports: ADSL1, ADSL2, SHDSL, Ethernet1, and Ethernet2.](cc72b4769f15fe33763025416c1e274d_img.jpg) + +ADSL1 port +ADSL2 port +SHDSL port TX +RX +AC port +USB port +Ethernet1 port TX +RX +Ethernet2 port TX +RX + +Example of different "Port types": +ADSL, AC, USB, SHDSL, Ethernet + +ADSL1 port + +Example of a "Single pair port": ADSL1 + +ADSL2 port + +Example of another "single pair port": ADSL2 (of the same port type) + +SHDSL port TX +RX + +Example of a "Multiple pairs port": SHDSL + +Ethernet1 port TX +RX + +Example of another "Multiple pairs port": Ethernet1 (of a different port type) + +Ethernet2 port TX +RX + +Example of another "Multiple pairs port": Ethernet2 (of the same port type (as Eth1)) + +ADSL1 port +ADSL2 port +SHDSL port TX +RX +Ethernet1 port TX +RX +Ethernet2 port TX +RX + +Example of "Multiple pair ports": +ADSL1, ADSL2, SHDSL, Ethernet1, Ethernet2 + +K.44(17)\_FA.2-5 + +Figure A.2-5 – Examples of equipment ports. The figure shows seven examples of equipment port configurations. Example 1 shows a variety of port types: ADSL1, ADSL2, SHDSL (TX/RX), AC, USB, Ethernet1 (TX/RX), and Ethernet2 (TX/RX). Examples 2 and 3 show single pair ports for ADSL1 and ADSL2 respectively. Example 4 shows a multiple pairs port for SHDSL. Examples 5 and 6 show multiple pairs ports for Ethernet1 and Ethernet2 respectively. Example 7 shows a combination of multiple pair ports: ADSL1, ADSL2, SHDSL, Ethernet1, and Ethernet2. + +**Figure A.2-5 – Examples of equipment ports** + +For a test on an external or internal port with single pair (single pair port), +the surge test is applied on that pair (Test 1). +If there are different ports of the same type, the surge test (lightning only) is +then repeated on the specified number of pairs of that port type simultaneously (Test 2). + +![Diagram illustrating two test scenarios for ADSL ports. Test 1 shows a single ADSL1 or ADSL2 port with one pair of wires. Test 2 shows a combined ADSL1 and ADSL2 port with two pairs of wires. A large blue arrow points from Test 1 to Test 2.](67114ecf6da13c97a89aeff0d86885d5_img.jpg) + +The diagram shows two testing configurations. At the top, labeled 'Test 1' in a red oval, are two separate boxes: one labeled 'ADSL1 port' and another labeled 'ADSL2 port', separated by the word 'or'. Each box has a single pair of lines extending from it, ending in small circles. Below these, a large blue downward-pointing arrow leads to a single box labeled 'ADSL1 port' and 'ADSL2 port'. This lower configuration is labeled 'Test 2' in a green oval and shows two pairs of lines extending from the box, each ending in small circles, indicating simultaneous testing of multiple ports. + +Diagram illustrating two test scenarios for ADSL ports. Test 1 shows a single ADSL1 or ADSL2 port with one pair of wires. Test 2 shows a combined ADSL1 and ADSL2 port with two pairs of wires. A large blue arrow points from Test 1 to Test 2. + +K.44(17)\_FA.2-6 + +NOTE 1 – The tests are specified in clause 10. + +NOTE 2 – The tests on this Figure mainly apply to line cards with a large number +of ADSL ports. + +**Figure A.2-6 – Examples of equipment ports** + +For a test on an EXTERNAL port with multiple pairs (multiple pairs port), the surge test is applied on each pair as for a test on a single pair port (Tests 1 and 2). The surge test (lightning only) is then repeated on the specified number of pairs of that port simultaneously (Test 3). + +![Diagram illustrating surge testing on SHDSL ports. Test 1 shows a TX port with one pair being tested. Test 2 shows an RX port with one pair being tested. Test 3 shows a multi-pair SHDSL port with multiple TX and RX pairs being tested simultaneously. A large blue arrow points from Tests 1 and 2 down to Test 3.](70a863dc6cd47bac82c12162a9479aac_img.jpg) + +The diagram illustrates three surge testing scenarios for SHDSL ports: + +- Test 1:** A single pair (TX) on an SHDSL port is shown with a surge test symbol (a blue oval with a line through it). +- Test 2:** A single pair (RX) on an SHDSL port is shown with a surge test symbol. +- Test 3:** A multi-pair SHDSL port (with multiple TX and RX pairs) is shown with a surge test symbol applied to all pairs simultaneously. + +A large blue arrow points from the individual tests (Test 1 and Test 2) down to the simultaneous test (Test 3). + +K.44(17)\_FA.2-7 + +Diagram illustrating surge testing on SHDSL ports. Test 1 shows a TX port with one pair being tested. Test 2 shows an RX port with one pair being tested. Test 3 shows a multi-pair SHDSL port with multiple TX and RX pairs being tested simultaneously. A large blue arrow points from Tests 1 and 2 down to Test 3. + +NOTE – The tests are specified in clause 10. + +**Figure A.2-7 – Examples of equipment ports** + +For a test on a product with external ports that consist of different port types, each connected to a single pair or multiple pairs, the surge test is applied on each pair as for a test on a single pair (Tests 1, 2 and 3). The surge test (lightning only) is then repeated on the specified number of pairs simultaneously (Test 4). + +![Diagram illustrating surge test configurations for external ports. Test 1 shows an ADSL1 port. Test 2 shows an ADSL2 port. Test 3 shows an SHDSL port with TX and RX pairs. Test 4 shows a combination of all these ports being tested simultaneously. A large blue arrow points from the individual tests to the combined test.](4ae4505e885586e481a3ad3bff5198b7_img.jpg) + +The diagram shows four test scenarios for external ports. Test 1, Test 2, and Test 3 are individual tests on ADSL1, ADSL2, and SHDSL (TX and RX) ports respectively. Test 4 is a combined test where all these ports are tested simultaneously. A large blue arrow points from the individual tests to the combined test. + +Diagram illustrating surge test configurations for external ports. Test 1 shows an ADSL1 port. Test 2 shows an ADSL2 port. Test 3 shows an SHDSL port with TX and RX pairs. Test 4 shows a combination of all these ports being tested simultaneously. A large blue arrow points from the individual tests to the combined test. + +K.44(17)\_FA.2-8 + +NOTE – The tests are specified in clause 10. + +**Figure A.2-8 – Examples of equipment ports** + +For surge tests on internal ports with a single pair or multiple pairs, the surge test (lightning only) is applied to all pairs of that port simultaneously (Test 1). + +![Diagram illustrating surge test configurations for internal ports. Test 1 shows an Ethernet1 port with TX and RX pairs. Test 2 shows an Ethernet2 port with TX and RX pairs. The word 'or' is placed between the two port types.](82fbb97c1145cac89ac72dd080fad17a_img.jpg) + +The diagram shows two test scenarios for internal ports. Test 1 shows an Ethernet1 port with TX and RX pairs. Test 2 shows an Ethernet2 port with TX and RX pairs. The word 'or' is placed between the two port types. + +Diagram illustrating surge test configurations for internal ports. Test 1 shows an Ethernet1 port with TX and RX pairs. Test 2 shows an Ethernet2 port with TX and RX pairs. The word 'or' is placed between the two port types. + +K.44(17)\_FA.2-9 + +NOTE – The tests are specified in clause 10. + +**Figure A.2-9 – Examples of equipment ports** + +### A.2.2 Equipment type + +Equipment may be of two general types: earthed and floating. Generally, TCE will be of the earthed type. Access network (AN) equipment and customer equipment may be either type. + +### A.2.3 Protection type + +Protecting equipment from high current surges is achieved by either installing primary protection or using equipment with integral high current protection. Generally, TCE will be protected by primary + +protection installed on the MDF. Access network equipment (ANE) may be protected using either method. Customer equipment would normally be protected by installing primary protection. + +### A.2.4 Equipment conditions and states + +As the components in the equipment, which are connected to the equipment port under test, may vary depending on which state the equipment is in, the equipment must be tested in all operating states of significant duration. Examples of equipment states that may need to be considered include: + +- handset "on hook" and "off hook"; +- power feed "on" and "off"; +- during ring; +- during line test cycle, etc. + +## A.3 Test generators + +Examples of circuits of test generators, which can be used to generate the waveforms specified in clause A.4, are contained in Figures A.3-1 to A.3-6. While the components shown should give the correct waveform, they may require adjustment. + +Alternative test generators may be used providing that they give the same result. + +![Circuit diagram of a 10/700 μs voltage surge generator. It features a switch S1 connected to a voltage source U_c. A parallel combination of a resistor R1 = 50 Ω and a capacitor C1 = 20 μF is connected across the source. This is followed by a series resistor R2 = 15 Ω and a capacitor C2 = 0.2 μF. The output terminals are connected to current limit resistors R, labeled g1, g2, ..., g1n, g2n, and a common Return line. The diagram is labeled K.44(17)_FA.3-1.](3b00a61116faef21d3a6009fd350b46a_img.jpg) + +Circuit diagram of a 10/700 μs voltage surge generator. It features a switch S1 connected to a voltage source U\_c. A parallel combination of a resistor R1 = 50 Ω and a capacitor C1 = 20 μF is connected across the source. This is followed by a series resistor R2 = 15 Ω and a capacitor C2 = 0.2 μF. The output terminals are connected to current limit resistors R, labeled g1, g2, ..., g1n, g2n, and a common Return line. The diagram is labeled K.44(17)\_FA.3-1. + +NOTE 1 – The 10/700 open-circuit voltage waveshape shall have a front time of $10 \mu\text{s} \pm 3 \mu\text{s}$ and a time to half value from virtual zero of $700 \mu\text{s} \pm 144 \mu\text{s}$ . + +NOTE 2 – The 5/320 short-circuit current waveshape in a single output of $R = 25 \Omega$ connected to the generator return shall have a front time of $5 \mu\text{s} \pm 1.0 \mu\text{s}$ and a time to half value from virtual zero of $320 \mu\text{s} \pm 64 \mu\text{s}$ . + +NOTE 3 – All resistors shall have a $\pm 5 \%$ tolerance and all capacitors a $\pm 10 \%$ tolerance. + +**Figure A.3-1 – 10/700 μs voltage surge generator** + +![Circuit diagram of a 1.2/50 μs voltage surge generator. It features a switch S1 connected to a voltage source U_c. A parallel combination of a resistor R1 = 68 Ω and a capacitor C1 = 1 μF is connected across the source. This is followed by a series resistor R2 = 13 Ω and a capacitor C2 = 30 nF. The output terminals are connected to current limit resistors R, labeled g1, g2, and a common Return line. The diagram is labeled K.44(18)_FA.3-2.](ddd86d7df6cf14d68c0faf111c1e8fae_img.jpg) + +Circuit diagram of a 1.2/50 μs voltage surge generator. It features a switch S1 connected to a voltage source U\_c. A parallel combination of a resistor R1 = 68 Ω and a capacitor C1 = 1 μF is connected across the source. This is followed by a series resistor R2 = 13 Ω and a capacitor C2 = 30 nF. The output terminals are connected to current limit resistors R, labeled g1, g2, and a common Return line. The diagram is labeled K.44(18)\_FA.3-2. + +NOTE 1 – The 1.2/50 open-circuit voltage waveshape shall have a front time of $1.2 \mu\text{s} \pm 0.36 \mu\text{s}$ and a time to half value from virtual zero of $50 \mu\text{s} \pm 10 \mu\text{s}$ as defined in IEC 60060-1:2010. + +NOTE 2 – All resistors shall have a $\pm 5 \%$ tolerance and all capacitors a $\pm 10 \%$ tolerance. + +**Figure A.3-2 – 1.2/50 μs voltage surge generator** + +The test generator may be a 1.2/50-8/20 combination wave generator as detailed in Figure A.3-5 or an equivalent 1.2/50 voltage surge generator. + +![Circuit diagram of a 2/10 μs voltage surge generator. A charging capacitor C = 20 μF is connected to a switch and a voltage source Uc. The switch is connected to an inductor L = 0.5 μH. The inductor is connected to a node that branches into two parallel current limit resistors R, labeled g1 and g2. A resistor R1 = 0.5 Ω is connected between this node and the common Return line. The diagram is labeled K.44(17)_FA.3-3.](b05bae46f7079e5c9b1da38adb2319e8_img.jpg) + +``` + +graph LR + Source((Uc)) --- Cap[C = 20 μF] + Cap --- Switch{/} + Switch --- Ind[L = 0.5 μH] + Ind --- Node1 + Node1 --- Res1[R1 = 0.5 Ω] --- Return[Return] + Node1 --- ResR1[R] --- g1[g1] + Node1 --- ResR2[R] --- g2[g2] + Return --- K44[K.44(17)_FA.3-3] + +``` + +Circuit diagram of a 2/10 μs voltage surge generator. A charging capacitor C = 20 μF is connected to a switch and a voltage source Uc. The switch is connected to an inductor L = 0.5 μH. The inductor is connected to a node that branches into two parallel current limit resistors R, labeled g1 and g2. A resistor R1 = 0.5 Ω is connected between this node and the common Return line. The diagram is labeled K.44(17)\_FA.3-3. + +L is small and mostly parasitic inductance of the wiring, may need to be adjusted to give the required front time of 2 μs. $U_c$ is adjusted to give required o/c output voltage + +**Figure A.3-3 – 2/10 μs voltage surge generator** + +![Circuit diagram of a six output 8/20 current generator. A charging capacitor C = 44.4 μF is connected to a switch. The switch is connected to a node that branches into six parallel branches. Each branch contains an inductor (L1 through L6) in series with a resistor (R1 through R6), leading to outputs o1 through o6. The inductors are labeled L1, L2, L3, L4, L5, L6 and the resistors are labeled R1, R2, R3, R4, R5, R6. Below the diagram, the values are given as L1 = L2 = L3 = L4 = L5 = L6 = 9.7 μH and R1 = R2 = R3 = R4 = R5 = R6 = 1.03 Ω. The diagram is labeled K.44(17)_FA.3-4.](cf8bd014a50b7c69435e804f67f9617f_img.jpg) + +``` + +graph LR + Cap[C = 44.4 μF] --- Switch{/} + Switch --- Node1 + Node1 --- L1[L1] --- R1[R1] --- o1[o1] + Node1 --- L2[L2] --- R2[R2] --- o2[o2] + Node1 --- L3[L3] --- R3[R3] --- o3[o3] + Node1 --- L4[L4] --- R4[R4] --- o4[o4] + Node1 --- L5[L5] --- R5[R5] --- o5[o5] + Node1 --- L6[L6] --- R6[R6] --- o6[o6] + Return[Return] --- K44[K.44(17)_FA.3-4] + +``` + +$L1 = L2 = L3 = L4 = L5 = L6 = 9.7 \mu\text{H}$ + $R1 = R2 = R3 = R4 = R5 = R6 = 1.03 \Omega$ + +Circuit diagram of a six output 8/20 current generator. A charging capacitor C = 44.4 μF is connected to a switch. The switch is connected to a node that branches into six parallel branches. Each branch contains an inductor (L1 through L6) in series with a resistor (R1 through R6), leading to outputs o1 through o6. The inductors are labeled L1, L2, L3, L4, L5, L6 and the resistors are labeled R1, R2, R3, R4, R5, R6. Below the diagram, the values are given as L1 = L2 = L3 = L4 = L5 = L6 = 9.7 μH and R1 = R2 = R3 = R4 = R5 = R6 = 1.03 Ω. The diagram is labeled K.44(17)\_FA.3-4. + +NOTE 1 – Any unused output shall be connected to the generator Return terminal to maintain the correct output current waveshape. + +NOTE 2 – The 2 kV charge voltage is for 1 kA on each output. The 10 kV charge voltage is for 5 kA on each output. + +NOTE 3 – The 8/20 short-circuit current waveshape shall be according to [IEC 62475] having a front time of $8 \mu\text{s} \pm 20\%$ and a time to half value from virtual zero of $20 \mu\text{s} \pm 20\%$ . The opposite polarity current undershoot shall not exceed 30% of the peak current. + +NOTE 4 – The capacitor C tolerance is $\pm 10\%$ and $\pm 5\%$ for the resistors and inductors. For safety, a bleed resistor should be connected across the charging capacitor to ensure that it is completely discharged in the longer term. + +**Figure A.3-4 – Six output 8/20 current generator** + +Equivalent test generator arrangements may be made by adding current sharing resistors to the output of standard generators. After the addition of current sharing resistors the short circuit output current must be an [IEC 62475] compliant 8/20 waveshape of the required amplitude. Sufficient voltage must be available to cause conduction of all the equipment primary protection components under test. Such test generators may be: + +- any 8/20 surge current generator capable of producing the required current waveform and sufficient voltage; +- if suitable, a combination wave generator, as detailed in Figure A.3-5, capable of producing the required current waveform and sufficient voltage. + +![Circuit diagram of a combination wave generator (Figure A.3-5).](e8e818455bb0d1a6153299a388b94868_img.jpg) + +The diagram shows a 1.2/50-8/20 combination wave generator (simplified circuit for SPICE modelling) connected to current limit resistors. The generator circuit includes a switch $S_1$ , an inductor $L_1 = 10.9 \mu\text{H}$ , a resistor $R_2 = 0.841 \Omega$ , a capacitor $C_1 = 5.93 \mu\text{F}$ , a resistor $R_1 = 20.2 \Omega$ , and a resistor $R_3 = 26.1 \Omega$ . The output terminals are labeled $g_1$ , $g_2$ , $g_{1n}$ , and $g_{2n}$ , with a return line. The current limit resistors are labeled $R$ . The diagram is labeled K.44(17)\_FA.3-5. + +Circuit diagram of a combination wave generator (Figure A.3-5). + +NOTE 1 – The 1.2/50 open-circuit voltage waveshape shall be according to [IEC 60060-1] having a front time of $1.2 \mu\text{s} \pm 30\%$ and a time to half value from virtual zero of $50 \mu\text{s} \pm 20\%$ . + +NOTE 2 – The 8/20 short-circuit current waveshape shall be according to [IEC 62475] having a front time of $8 \mu\text{s} \pm 20\%$ and a time to half value from virtual zero of $20 \mu\text{s} \pm 20\%$ . The opposite polarity current undershoot shall not exceed 30% of the peak current. + +NOTE 3 – The ratio of peak open-circuit voltage to short-circuit current $R_1$ shall be $2 \Omega \pm 10\%$ . + +**Figure A.3-5 – Combination wave generator** + +![Circuit diagram of a power induction, power contact and rise of neutral potential generator (Figure A.3-6).](67d03c9e89620d73e3786c869e559752_img.jpg) + +The diagram shows a power induction, power contact and rise of neutral potential generator. It consists of an AC voltage source $U_{(AC)}$ connected to a switch $SW$ . The switch is connected to two current limit resistors $R$ , which are connected to output terminals $g_1$ and $g_2$ . A timing circuit is also connected to the switch. The diagram is labeled K.44(18)\_FA.3-6. + +Circuit diagram of a power induction, power contact and rise of neutral potential generator (Figure A.3-6). + +For the value of $R$ , refer to the appropriate test table in the appropriate product Recommendation. + +NOTE – If national regulations require it, the maximum current may be limited. + +**Figure A.3-6 – Power induction, power contact and rise of neutral potential generator** + +## A.4 Waveform generation + +Where circuit values are provided, use this circuit. Where generator circuits are not given, refer to the quoted IEC standard, or [IEC 60060-1]/[IEC 62475] for guidance on verifying the waveform. + +The following tolerances should be observed for both the power induction and power contact tests: + +Voltage –0% to +5% + +Current –0% to +5% + +Time –0% to +10% + +The procedure for verifying the tolerances of the above parameters for Figure A.3-6 is given below. + +Step 1 With both of the output terminals $g_1$ and $g_2$ in an open-circuit condition, check that the voltage is within the allowed tolerance. + +Step 2 With both of the output terminals $g_1$ and $g_2$ in short-circuit condition, check that the current is within the allowed tolerance. + +Step 3 With the output terminal $g_1$ in an open-circuit condition and with $g_2$ in a short-circuit condition, check that the voltage on terminal $g_1$ and the current in circuit $g_2$ are within the allowed tolerance. + +- Step 4 With the output terminal $g_2$ in an open-circuit condition and with $g_1$ in a short-circuit condition, check that the voltage on terminal $g_2$ and the current in circuit $g_1$ are within the allowed tolerance. +- Step 5 With both of the output terminals $g_1$ and $g_2$ in an open-circuit condition, check that the length of the surge is within the allowed tolerance. + +## **A.5 Powering, coupling, decoupling and terminations** + +### **A.5.1 General** + +The surge generator, powering, coupling and decoupling elements, the EUT and terminations are connected as shown in Figure A.5-1. + +![Block diagram of a typical test set-up showing a test generator connected to current limiting resistors, coupling elements, and the Equipment Under Test (EUT) with various protective and auxiliary components.](c1df61cc3717e878a48e530218403403_img.jpg) + +The diagram illustrates a typical test set-up. On the left, a 'Test generator (See Figures A.3-1-A.3-6)' has an 'Output' terminal connected to a 'Current limiting resistors' block containing two resistors labeled 'R'. The 'Return' terminal of the generator is connected to 'Generator return/Earth', which is grounded. The 'Output' terminal also connects to a 'Coupling element (See Table A.5-1)'. This coupling element is part of a 'Powering, auxiliary equipment, or terminations, as required, and decoupling networks. (See Figures A.5-3-A.5-9)' block, which has an 'E' (Earth) terminal. The signal from the coupling element passes through a 'Special test protector, when required, for the test' block, which contains a diode symbol. The signal then enters the 'EUT Int. or Ext. ports' block, which has terminals labeled 'a', 'b', 'an', and 'bn'. A 'Port coupled to earth' is indicated by an arrow pointing to the 'a' terminal. The 'EUT Int. or Ext. ports' block has an 'E' (Earth) terminal and is connected to an 'EUT reference' bar. To the right of the EUT, there is an 'Appropriate primary protection, or special test protector, when required for the test. (See Figures A.5-17-A.5-20)' block, which also has an 'E' (Earth) terminal connected to the EUT reference bar. Further right, there are two 'Powering, auxiliary equipment or terminations as required, coupling-to-earth and decoupling networks. (See Figures A.5-10-A.5-16)' blocks, each with an 'E' (Earth) terminal connected to the EUT reference bar. The EUT reference bar is connected to the 'Generator return/Earth' line. + +Block diagram of a typical test set-up showing a test generator connected to current limiting resistors, coupling elements, and the Equipment Under Test (EUT) with various protective and auxiliary components. + +K.44(17)\_FA.5-1 + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.5-1 – Block diagram of a typical test set-up** + +Coupling elements are used to connect the surge generator to the EUT and to connect other ports/lines to earth during port-to-port testing. The coupling element, if required, can be a MOV, a GDT, a capacitor or any other element with an operating voltage in excess of the maximum EUT working voltage. The coupling element should be considered as an integral part of the test generator and should not significantly affect the open-circuit voltage nor the short-circuit current. It may be necessary to increase the test voltage to compensate for voltage drop in coupling elements. There are a number of ways of connecting coupling elements to earth and some examples are shown in Figure A.5-2b. + +Decoupling elements are used to reduce the level of surge, which would otherwise enter the powering equipment, auxiliary equipment or terminations. The decoupling elements, if necessary, have an impedance that reduces the level of surge entering the line simulator (e.g., a resistance of 200 $\Omega$ or greater, for symmetric pair circuits, an inductor or a choke) but still allowing power and signalling to take place to the EUT. It has to be proven (e.g., by calibration) that the decoupling network does not influence the pulse shape and the test level; otherwise, the test levels have to be adjusted to achieve the correct level. The equipment is powered via the mains or dpf port, etc., through an appropriate decoupling network, e.g., isolation transformer or chokes, etc. + +An example of terminations of untested ports is given in Figure A.5-2a. All ports, including the test port, would normally be terminated in some way. Decoupling elements are used to prevent damage to the auxiliary equipment or termination. When required for the test, the appropriate untested port is coupled to earth by using a coupling element. + +NOTE – For high speed data circuits it has been found that a more accurate result can be achieved by connecting up to 100 metres of cable between the EUT and the associated data circuit equipment. Using a simple termination may not detect data problems which can later be experienced in the field. + +![Figure A.5-2a: Example of termination and coupling to earth of untested port. The diagram shows an EUT (Equipment Under Test) with various ports. On the left, a 'Symmetric pair port' has terminals 'a' and 'b' connected to terminations Z1 and Z2, with SPDs (Surge Protection Devices) connected to earth. Above the EUT, a 'Coaxial port' is connected to a termination Z3 and an SPD. To the right, there are power input ports labeled 'L', 'N', and 'E'. The 'L' and 'N' lines have SPDs and are connected to a termination network. A note indicates that termination on the mains port is not required as the a.c. power provides the termination. Another note states that termination on a special power feed (dpf1, dpf2) is not required as the power supply provides the termination. A shield* is also shown connected to earth. A note at the bottom right states: '* Connect N and shield to earth if connected to earth in practice.' The diagram is labeled K.44(17)_FA.5-2a.](7fe5741e83bc9702d1b1d7585ddf66bd_img.jpg) + +Figure A.5-2a: Example of termination and coupling to earth of untested port. The diagram shows an EUT (Equipment Under Test) with various ports. On the left, a 'Symmetric pair port' has terminals 'a' and 'b' connected to terminations Z1 and Z2, with SPDs (Surge Protection Devices) connected to earth. Above the EUT, a 'Coaxial port' is connected to a termination Z3 and an SPD. To the right, there are power input ports labeled 'L', 'N', and 'E'. The 'L' and 'N' lines have SPDs and are connected to a termination network. A note indicates that termination on the mains port is not required as the a.c. power provides the termination. Another note states that termination on a special power feed (dpf1, dpf2) is not required as the power supply provides the termination. A shield\* is also shown connected to earth. A note at the bottom right states: '\* Connect N and shield to earth if connected to earth in practice.' The diagram is labeled K.44(17)\_FA.5-2a. + +$Z_1$ , $Z_2$ and $Z_3$ are the nominal terminations for a working system or associated equipment. The SPDs are used to couple the required untested port to ground in turn. + +**Figure A.5-2a – Example of termination and coupling to earth of untested port** + +![Figure A.5-2b shows three circuit diagrams illustrating the connection of coupling elements to earth. Diagram (a) shows a 3-electrode GDT connected between two lines and earth. Diagram (b) shows MOVs connected in a delta configuration between two lines and earth. Diagram (c) shows MOVs connected in a star configuration between two lines and earth. The text 'K.44(17)_FA.5-2b' is located below the diagrams.](12c19090355e19922e23044633b9d1ea_img.jpg) + +Figure A.5-2b shows three circuit diagrams illustrating the connection of coupling elements to earth. Diagram (a) shows a 3-electrode GDT connected between two lines and earth. Diagram (b) shows MOVs connected in a delta configuration between two lines and earth. Diagram (c) shows MOVs connected in a star configuration between two lines and earth. The text 'K.44(17)\_FA.5-2b' is located below the diagrams. + +**Figure A.5-2b – Examples of connecting coupling elements to earth** + +Recommended component values for coupling and decoupling elements are provided in Table A.5-1. Record the method used in the test report. Many of the circuits referenced in Table A.5-1 are under study as they were designed circa 2000 and have not necessarily kept up with the needs of modern communications technology. + +**Table A.5-1 – Recommended coupling and decoupling elements** + +| Port type | Test ports | | Untested ports | | | +|---------------------------------|-----------------------------------|-----------------------------|-----------------------------|------------------------------------|-------------------------------------| +| | Generator coupling elements | Decoupling element (Note 2) | Decoupling element (Note 2) | Coupling element to earth | Protection for untested port on EUT | +| External symmetric pair ports | GDTs or MOVs (Note 1) | See Figure A.5-3 | See Figure A.5-10 | GDT; see Figure A.5-10 | GDT; see Figure A.5-17 | +| External coaxial cable | GDT | See Figure A.5-4 | See Figure A.5-11 | A link; see Figure A.5-11 | GDT; see Figure A.5-18 | +| External dpf cable ports | MOVs | See Figure A.5-5 | See Figure A.5-12 | MOVs; see Figure A.5-12 | MOVs; see Figure A.5-19 | +| Mains power ports | MOVs | See Figure A.5-6 | See Figure A.5-13 | MOV; see Figure A.5-13 | MOV; see Figure A.5-20 | +| Internal unshielded cable ports | GDTs or MOVs | See Figure A.5-7 | See Figure A.5-14 | Clamping diodes; see Figure A.5-14 | None required | +| Internal shielded cable ports | None required; see Figure A.6.5-2 | None required | See Figure A.5-15 | A link; see Figure A.5-15 | None required | +| Internal d.c. power ports | MOVs | See Figure A.5-9 | See Figure A.5-16 | MOVs; see Figure A.5-16 | None required | +| Ethernet ports | 10 Ω resistors | See Figure A.6.7-1 | See Figure A.6.7-1 | 10 Ω resistors; see Figure A.6.7-1 | None required | + +NOTE 1 – It is allowed (see clause 7.3 3) for the power contact test to be performed without the equipment powered providing it does not affect the test result. The power line contact test generator, Figure A.3-6 incorporates switch (SW) which acts as the coupling element when closed. For power contact testing, the Figure A.6.1-3 generator coupling elements are omitted. + +NOTE 2 – The value of the decoupling resistor may sometimes need to be reduced to enable the system to function. The value of this decoupling resistor should be recorded in the test report. + +### A.5.2 Tested ports + +#### A.5.2.1 External symmetric pair + +When an external symmetric port is the tested port, it is suggested that 200 $\Omega$ be inserted in series with each line leg between the AE and the generator. A 33 k $\Omega$ in parallel with a 125 V clamping device may be connected between each line leg and earth at the AE to further decouple the AE, see Figure A.5-3. This will limit the current conducted into the AE to a few amps but still allow xDSL, plain old telephone system (POTS) or ISDN transmission even when remote power feeding up to 120 V DC is used. Other values or methods, e.g., an artificial cable, are allowed. + +![Figure A.5-3: Decoupling network for AE connected to the tested external symmetric pair port.](3442f31a562d1ef45bfa18b18a6a1ddc_img.jpg) + +The diagram illustrates a circuit for a decoupling network. On the left, a box represents "Auxiliary equipment" with three terminals: 'a', 'b', and 'E'. Terminals 'a' and 'b' connect to a dashed box labeled "Decoupling network". Inside this network, terminal 'a' branches to a 33 k $\Omega$ resistor and a 150 V gas discharge tube (GDT) in parallel, both leading to a common ground line labeled "Generator return/Earth". Terminal 'a' also continues through a 200 $\Omega$ series resistor to an output. Terminal 'b' follows an identical path with its own 33 k $\Omega$ resistor, 150 V GDT, and 200 $\Omega$ series resistor. Terminal 'E' of the auxiliary equipment connects directly to the "Generator return/Earth" line. The diagram is identified by the code K.44(18)\_FA.5-3. + +Figure A.5-3: Decoupling network for AE connected to the tested external symmetric pair port. + +NOTE – The 200 $\Omega$ resistors must be capable to dissipate the power resulting from the applied test voltage + +**Figure A.5-3 – Decoupling network for AE connected to the tested external symmetric pair port** + +#### A.5.2.2 External coaxial cable port + +When an external coaxial port is the tested port, it is suggested that a capacitor be inserted in series with the centre conductor between the AE and the generator. A coaxial 230 V GDT may be connected at the AE to further decouple the AE, see Figure A.5-4. This will limit the energy entering the AE but still allow transmission. A higher firing voltage GDT may be used if it is necessary for the application. + +A high value inductance may be connected in parallel with the capacitor to allow remote power feeding, e.g., 120 V DC. Other values or methods, e.g., an artificial cable, are allowed. + +![Figure A.5-4: Decoupling network for AE connected to the tested external coaxial cable port. The diagram shows an 'Auxiliary equipment' box connected to a 'Decoupling network' (dashed box) and a coaxial cable. The network contains a 230V clamping device between the line and earth, and an inductor (L) and capacitor (C) in series on the line. A note indicates 'Coax length should be as short as practicable'. The label K.44(17)_FA.5-4 is present.](dbd074feb5cce1300f42f91da8f673d1_img.jpg) + +Figure A.5-4: Decoupling network for AE connected to the tested external coaxial cable port. The diagram shows an 'Auxiliary equipment' box connected to a 'Decoupling network' (dashed box) and a coaxial cable. The network contains a 230V clamping device between the line and earth, and an inductor (L) and capacitor (C) in series on the line. A note indicates 'Coax length should be as short as practicable'. The label K.44(17)\_FA.5-4 is present. + +$C > 5 / (2 \times \pi \times f \times Z_0)$ , where $\pi = 3.1416$ , $f$ is the lower frequency used by the EUT and $Z_0$ is the characteristic impedance of the coaxial cable. the upper bound to $C$ is 50 nF. + +The inductance $L$ is only required when there is a DC powerfeed. A 3 mH air-core inductor is sufficient to decouple the surge from the power equipment. Note that an air cored inductor is recommended as the magnetizing current of steel core inductors can be a problem. + +**Figure A.5-4 – Decoupling network for AE connected to the tested external coaxial cable port** + +#### A.5.2.3 External dedicated power feed port + +When an external dedicated power feed port is the tested port, it is suggested that 3 mH be inserted in series with each line leg between the AE and the generator. A 125 V clamping device may be connected between each line leg and earth at the AE to further decouple the AE, see Figure A.5-5. This will limit the current conducted into the AE to a few amps for power feeding up to 120 V DC. Other values or methods, e.g., an artificial cable, are allowed. + +![Figure A.5-5: Decoupling network for AE connected to the tested external dpf pair port. The diagram shows a 'Power supply' box connected to a 'Decoupling network' (dashed box) and a 'Generator return/Earth' line. The network contains two 125V clamping devices between the lines and earth, and two 3 mH inductors in series on the lines. The label K.44(17)_FA.5-5 is present.](753e6cc5dcad1a478caa2c7ec3a6c0a3_img.jpg) + +Figure A.5-5: Decoupling network for AE connected to the tested external dpf pair port. The diagram shows a 'Power supply' box connected to a 'Decoupling network' (dashed box) and a 'Generator return/Earth' line. The network contains two 125V clamping devices between the lines and earth, and two 3 mH inductors in series on the lines. The label K.44(17)\_FA.5-5 is present. + +**Figure A.5-5 – Decoupling network for AE connected to the tested external dpf pair port** + +#### A.5.2.4 Mains ports + +When the mains port is the tested port, it is necessary to decouple the mains source during testing for transverse/differential, port to earth and port to external port surges to protect the power source. Proposed decoupling elements are shown in Figure A.5-6. + +![Figure A.5-6: Decoupling network for the power supply connected to the tested mains port. The diagram shows a 240 V AC source connected to the primary winding (L2, N2) of an isolation transformer. The secondary winding (L1, N1) is connected to the test equipment through two 1.5 mH inductors. The entire decoupling network is enclosed in a dashed box labeled 'Decoupling network'. The reference K.44(17)_FA.5-6 is shown below the diagram.](2580688a4de0a29692805cc6ba4822d7_img.jpg) + +Figure A.5-6: Decoupling network for the power supply connected to the tested mains port. The diagram shows a 240 V AC source connected to the primary winding (L2, N2) of an isolation transformer. The secondary winding (L1, N1) is connected to the test equipment through two 1.5 mH inductors. The entire decoupling network is enclosed in a dashed box labeled 'Decoupling network'. The reference K.44(17)\_FA.5-6 is shown below the diagram. + +**Figure A.5-6 – Decoupling network for the power supply connected to the tested mains port** + +If the recommended decoupling element cannot be used for the test, this fact should be noted in the test report. The value of the modified decoupling element should be reported along with the potential impact on the test result. + +#### A.5.2.5 Internal unshielded cable port + +When an internal unshielded cable port is the tested port, it is suggested that 200 Ω be inserted in series with each line leg between the AE and the generator. A 33 kΩ in parallel with an 18 V clamping device may be connected between each line leg and earth at the AE to further decouple the AE. This will limit the current conducted into the AE to a few amps. Other values or methods are allowed. + +![Figure A.5-7: Decoupling network for AE connected to the tested internal unshielded cable port. The diagram shows a complex network for four conductors (a, b, an, bn) and earth (E). Each conductor has a 200 Ω resistor in series. Between each conductor and earth, there is a 33 kΩ resistor in parallel with an 18 V clamping diode. The network is enclosed in a dashed box labeled 'Decoupling network'. The reference K.44(17)_FA.5-7 is shown below the diagram.](aeb2a26a07219661191294dba528067a_img.jpg) + +Figure A.5-7: Decoupling network for AE connected to the tested internal unshielded cable port. The diagram shows a complex network for four conductors (a, b, an, bn) and earth (E). Each conductor has a 200 Ω resistor in series. Between each conductor and earth, there is a 33 kΩ resistor in parallel with an 18 V clamping diode. The network is enclosed in a dashed box labeled 'Decoupling network'. The reference K.44(17)\_FA.5-7 is shown below the diagram. + +**Figure A.5-7 – Decoupling network for AE connected to the tested internal unshielded cable port** + +NOTE – Normally, 18 V clamping diodes are used to protect the internal interface. If these diodes prevent normal operation, a diode with a higher clamping voltage may be used. If the 200 Ω decoupling resistor prevents normal operation, a resistor with a lower value may be used. + +#### A.5.2.6 Internal shielded cable port + +Figure A.5-8 has been deleted. + +NOTE – A decoupling network is not required for auxiliary equipment connected to the tested internal shielded cable port. See Figure A.6.5-2. + +#### A.5.2.7 Internal DC power interface + +The cable connecting the power source equipment and the powered equipment can have sufficient inductance to decouple the two pieces of equipment. To emulate this, it is suggested that 3 mH inductor be inserted in series with each powering conductor, see Figure A.5-9. Other values or methods, e.g., an artificial cable, are allowed. + +![Diagram of an internal DC power interface showing a decoupling network between a DC power source equipment and a DC powered equipment. The diagram includes three conductors: +V, 0 V (if used), and -V. The decoupling network, enclosed in a dashed box, contains three inductors labeled L1, L3, and L2 in series with the respective conductors. The +V conductor connects to the +V terminal of the DC power source equipment, passes through inductor L1, and connects to the +V terminal of the DC powered equipment. The 0 V (if used) conductor connects to the 0 V (if used) terminal of the DC power source equipment, passes through inductor L3, and connects to the 0 V (if used) terminal of the DC powered equipment. The -V conductor connects to the -V terminal of the DC power source equipment, passes through inductor L2, and connects to the -V terminal of the DC powered equipment. Both equipment boxes have an 'E' (earth) terminal. A line labeled 'Surge generator return/earth' connects the 'E' terminal of the DC power source equipment to the 'E' terminal of the DC powered equipment. The diagram is labeled K.44(18)_FA.5-9 at the bottom right.](df1966d80c74bc127f159a48f38b13ee_img.jpg) + +Diagram of an internal DC power interface showing a decoupling network between a DC power source equipment and a DC powered equipment. The diagram includes three conductors: +V, 0 V (if used), and -V. The decoupling network, enclosed in a dashed box, contains three inductors labeled L1, L3, and L2 in series with the respective conductors. The +V conductor connects to the +V terminal of the DC power source equipment, passes through inductor L1, and connects to the +V terminal of the DC powered equipment. The 0 V (if used) conductor connects to the 0 V (if used) terminal of the DC power source equipment, passes through inductor L3, and connects to the 0 V (if used) terminal of the DC powered equipment. The -V conductor connects to the -V terminal of the DC power source equipment, passes through inductor L2, and connects to the -V terminal of the DC powered equipment. Both equipment boxes have an 'E' (earth) terminal. A line labeled 'Surge generator return/earth' connects the 'E' terminal of the DC power source equipment to the 'E' terminal of the DC powered equipment. The diagram is labeled K.44(18)\_FA.5-9 at the bottom right. + +**Figure A.5-9 – Internal DC power interface – decoupling network between the power source equipment and powered equipment** + +The generator coupling elements consist of a 10 Ω resistor and a 9 µF capacitor connected in series. + +### A.5.3 Untested ports + +#### A.5.3.1 External symmetric pair + +When an external symmetric pair port is the untested port, it is suggested that 200 Ω be inserted in series with each line leg between the AE and the generator. A 33 kΩ in parallel with a 125 V clamping device may be connected between each line leg and earth at the AE to further decouple the AE. This will limit the current conducted into the AE to a few amps but still allow xDSL, POTS or ISDN transmission even when remote power feeding up to 120 V DC is used. + +The methods of termination and coupling to earth for untested external symmetric pair ports are shown in Figure A.5-10. + +![Two circuit diagrams, (a) and (b), showing the termination and coupling to earth of untested external symmetric pair ports. Diagram (a) shows a 'Decoupling network' with two 200 Ω resistors, two 125 V clamping diodes, and two 33 kΩ resistors connected to an 'Auxiliary equipment' (AE) and an 'EUT reference bar'. Diagram (b) shows a similar 'Decoupling network' but with a 'Coupling-to-earth element' (a current source) connected between the input lines 'a' and 'b' and 'Generator return/Earth'.](701bc79e78b382bcfd3ba85597dbb9c3_img.jpg) + +a) Termination of an untested external symmetric pair port + +b) Coupling to earth and termination of an untested external symmetric pair port + +K.44(17)\_FA.5-10 + +Two circuit diagrams, (a) and (b), showing the termination and coupling to earth of untested external symmetric pair ports. Diagram (a) shows a 'Decoupling network' with two 200 Ω resistors, two 125 V clamping diodes, and two 33 kΩ resistors connected to an 'Auxiliary equipment' (AE) and an 'EUT reference bar'. Diagram (b) shows a similar 'Decoupling network' but with a 'Coupling-to-earth element' (a current source) connected between the input lines 'a' and 'b' and 'Generator return/Earth'. + +NOTE – For Ethernet ports, refer to clause A.6.7 and Figure A.6.7-1 a) and b) for the coupling to earth and the decoupling and termination methods. + +**Figure A.5-10 – Termination and coupling to earth of untested external symmetric pair ports** + +#### A.5.3.2 External coaxial cable port + +When an external coaxial cable port is the untested port, it is suggested that the methods of termination and coupling to earth shown in Figure A.5-11 are used. Float the AE, and its power source, to "decouple" the AE. Ground the AE and its power supply to "couple" the EUT port to earth, see Figure A.5-18. + +![Diagram showing the termination and coupling to earth of untested external coaxial cable ports. It features a coaxial cable connected to 'Auxiliary equipment', which is connected to 'PS for AE'. Both the auxiliary equipment and the power supply have earth (E) terminals. These earth terminals are connected to a common 'Generator return/Earth' line. A switchable link is shown between the auxiliary equipment's earth terminal and the common earth line. Text indicates: 'Insert link to couple untested port to earth (normal operation)' and 'Remove link to decouple untested port from earth (terminated only)'. The diagram is labeled K.44(17)_FA.5-11.](89f8aefc01866631793087542316cef2_img.jpg) + +Diagram showing the termination and coupling to earth of untested external coaxial cable ports. It features a coaxial cable connected to 'Auxiliary equipment', which is connected to 'PS for AE'. Both the auxiliary equipment and the power supply have earth (E) terminals. These earth terminals are connected to a common 'Generator return/Earth' line. A switchable link is shown between the auxiliary equipment's earth terminal and the common earth line. Text indicates: 'Insert link to couple untested port to earth (normal operation)' and 'Remove link to decouple untested port from earth (terminated only)'. The diagram is labeled K.44(17)\_FA.5-11. + +**Figure A.5-11 – Termination and coupling to earth of untested external coaxial cable ports** + +#### A.5.3.3 External dedicated power feed port + +When an external dedicated power feed port is the untested port, it is suggested that 3 mH be inserted in series with each line leg between the AE and the generator. A 125 V clamping device may be connected between each line leg and earth at the AE to further decouple the AE, see Figure A.5-12. This will limit the current conducted into the AE to a few amps for power feeding up to 120 V DC. Other values or methods, e.g., an artificial cable, are allowed. + +![Figure A.5-12: Termination and coupling to earth of untested dpf ports. The figure contains two sub-diagrams, (a) and (b).](a2251e3bbfcd726b68cc50b091e53b02_img.jpg) + +Figure A.5-12 consists of two sub-diagrams, (a) and (b), illustrating the termination and coupling to earth of untested dpf ports. + +**a) Termination of an untested external dpf pair port** + +This diagram shows a 'Decoupling network' (dashed box) connected to 'Auxiliary equipment' (solid box). The network contains two 3 mH inductors in series with the ports pfv1 and pfv2. Each inductor is followed by a 125 V SPD connected to the 'EUT reference bar'. The auxiliary equipment has its own earth connection 'E'. + +**b) Coupling to earth and termination of an untested external dpf pair port** + +This diagram shows a 'Decoupling network' (dashed box) connected to 'Auxiliary equipment' (solid box). On the input side, there are 'Coupling-to-earth elements' consisting of two 125 V SPDs connected to 'Generator return/Earth'. The 'Decoupling network' contains two 3 mH inductors in series with the ports pfv1 and pfv2. Each inductor is followed by a 125 V SPD connected to the 'Generator return/Earth'. The auxiliary equipment has its own earth connection 'E'. The diagram is labeled K.44(17)\_FA.5-12. + +Figure A.5-12: Termination and coupling to earth of untested dpf ports. The figure contains two sub-diagrams, (a) and (b). + +**Figure A.5-12 – Termination and coupling to earth of untested dpf ports** + +#### A.5.3.4 Mains ports + +When the mains port is an untested port, three states for the mains network have to be considered, and these are: + +- the mains distribution network appears as a high impedance network. This applies for a non-earthed neutral installation, e.g., a TT power distribution system. In this case, use 1.5 mH inductors in the L1 and N conductors; +- the neutral is earthed at the customer premises, e.g., a type of power distribution system (TN-C) power distribution system. In this case, connect the neutral conductor to the generator return; +- both L1 and neutral are earthed under surge conditions, i.e., SPDs have been installed. In this case, connect the neutral to earth and install an SPD L1 to N/E. + +To test all possible scenarios and to allow testing under the conditions where the port is floating and coupled to earth, use the termination and coupling to earth methods shown in Figure A.5-13. + +![Figure A.5-13: Terminating and coupling to earth of untested mains ports. The figure contains two sub-diagrams, (a) and (b).](cbab05075b3d7dc0d27c4cbb0c914a94_img.jpg) + +Figure A.5-13 consists of two sub-diagrams, (a) and (b), illustrating the termination and coupling to earth of untested mains ports. + +**a) Termination of untested mains port** + +This diagram shows a "Decoupling network" (indicated by a dashed box) connected between the untested mains port (L1, N1) and the tested port (L2, N2). The network contains two 1.5 mH inductors in series with the lines L1 and N1, and an isolation transformer. The secondary of the isolation transformer is connected to a 230 V AC source. + +**b) Coupling to earth and termination of an untested mains port** + +This diagram shows the same "Decoupling network" as in (a), but with additional "Coupling-to-earth elements" (SPD) connected between the untested mains port (L1, N1) and the "Generator return/Earth". The SPD is connected between L1 and earth, and N1 and earth. + +K.44(17)\_FA.5-13 + +Figure A.5-13: Terminating and coupling to earth of untested mains ports. The figure contains two sub-diagrams, (a) and (b). + +**Figure A.5-13 – Terminating and coupling to earth of untested mains ports** + +#### A.5.3.5 Internal unshielded cable port + +When an internal unshielded cable port is the untested port, it is suggested that 200 Ω be inserted in series with each line leg between the AE and the generator. A 33 kΩ in parallel with an 18 V clamping device may be connected between each line leg and earth at the AE to further decouple the AE, see Figure A.5-14. This will limit the current conducted into the AE to a few amps. Other values or methods, e.g., an artificial cable, are allowed. + +![Circuit diagram of a decoupling network for terminating untested internal symmetric pair ports. The network consists of four identical signal paths (a, b, a_n, b_n). Each path enters through a 200 Ω series resistor. After the resistor, each line is connected to a common reference bar through an 18 V clamping diode and a 33 kΩ resistor in parallel. The signal lines then continue to the auxiliary equipment ports (a, b, a_n, b_n). The common reference bar is connected to the EUT reference bar and the auxiliary equipment ground terminal E. The diagram is labeled K.44(17)_FA.5-14a.](c0b9e5fc63e19306394e0d4249da62cd_img.jpg) + +The diagram illustrates a decoupling network used for the termination of untested internal symmetric pair ports. It consists of four signal lines labeled a, b, an, and bn. Each line passes through a 200 Ω series resistor. Following the resistor, each line is shunted to a common ground rail (EUT reference bar) via an 18 V clamping diode and a 33 kΩ resistor. The lines then terminate at corresponding ports on the auxiliary equipment. The auxiliary equipment's ground terminal E is also connected to the EUT reference bar. + +Circuit diagram of a decoupling network for terminating untested internal symmetric pair ports. The network consists of four identical signal paths (a, b, a\_n, b\_n). Each path enters through a 200 Ω series resistor. After the resistor, each line is connected to a common reference bar through an 18 V clamping diode and a 33 kΩ resistor in parallel. The signal lines then continue to the auxiliary equipment ports (a, b, a\_n, b\_n). The common reference bar is connected to the EUT reference bar and the auxiliary equipment ground terminal E. The diagram is labeled K.44(17)\_FA.5-14a. + +NOTE 1 – Normally, 18 V clamping diodes are used to protect the internal interface. If these diodes prevent normal operation, a diode with a higher clamping voltage may be used. If the 200- $\Omega$ decoupling resistor prevents normal operation, a resistor with a lower value may be used. + +NOTE 2 – For Ethernet ports, refer to clause A.6.7 and Figure A.6.7-1 a) for the decoupling and termination method. + +**Figure A.5-14a – Termination of untested internal symmetric pair ports** + +![Circuit diagram Figure A.5-14b: Coupling to earth and termination of untested internal symmetric pair ports. The diagram shows four signal lines labeled a, b, a_n, and b_n entering from the left. Each line passes through a 'Coupling-to-earth element' consisting of an 18 V clamping diode connected to 'Generator return/Earth'. Then, each line enters a 'Decoupling network' (dashed box) containing a 200 Ω series resistor. After the resistor, each line has another 18 V clamping diode to earth and a 33 kΩ shunt resistor connected to a common internal node. The lines exit to the right to 'Auxiliary equipment' terminals labeled a, b, a_n, and b_n. The auxiliary equipment block also has an earth terminal 'E'. The diagram is labeled K.44(17)_FA.5-14b.](51d4540605fdfa2c090638305022143b_img.jpg) + +Circuit diagram Figure A.5-14b: Coupling to earth and termination of untested internal symmetric pair ports. The diagram shows four signal lines labeled a, b, a\_n, and b\_n entering from the left. Each line passes through a 'Coupling-to-earth element' consisting of an 18 V clamping diode connected to 'Generator return/Earth'. Then, each line enters a 'Decoupling network' (dashed box) containing a 200 Ω series resistor. After the resistor, each line has another 18 V clamping diode to earth and a 33 kΩ shunt resistor connected to a common internal node. The lines exit to the right to 'Auxiliary equipment' terminals labeled a, b, a\_n, and b\_n. The auxiliary equipment block also has an earth terminal 'E'. The diagram is labeled K.44(17)\_FA.5-14b. + +NOTE 1 – Normally, 18 V clamping diodes are used to protect the internal interface. If these diodes prevent normal operation, a diode with a higher clamping voltage may be used. If the 200- $\Omega$ decoupling resistor prevents normal operation, a resistor with a lower value may be used. + +NOTE 2 – For Ethernet ports, refer to clause A.6.7 and Figure A.6.7-1 b) for the coupling to earth and the decoupling and termination method. + +**Figure A.5-14b – Coupling to earth and termination of untested internal symmetric pair ports** + +#### A.5.3.6 Internal shielded cable port + +When an internal shielded cable port is the untested port, it is suggested that the methods of termination and coupling to earth shown in Figure A.5-15 are used: + +- to "decouple" the AE from earth: float the AE and its power supply; +- to "couple" the AE to earth: connect the AE and its power supply to the generator return. + +![Circuit diagram Figure A.5-15: Terminating and coupling to earth of untested internal shielded cable ports. A shielded cable is shown on the left, with its shield and internal conductor connected to an 'Auxiliary equipment' block. The 'Auxiliary equipment' is connected to a 'PS for AE' (Power Supply) block via two lines. Both the AE and the PS have earth terminals 'E'. A switchable link connects these earth terminals to the 'Generator return/Earth'. Text below the switch explains: 'Insert link to couple untested port to earth (normal operation)' and 'Remove link to decouple untested port from earth (terminated only)'. The diagram is labeled K.44(17)_FA.5-15.](b774dfc5023e15e9c352b97ca25a56d4_img.jpg) + +Circuit diagram Figure A.5-15: Terminating and coupling to earth of untested internal shielded cable ports. A shielded cable is shown on the left, with its shield and internal conductor connected to an 'Auxiliary equipment' block. The 'Auxiliary equipment' is connected to a 'PS for AE' (Power Supply) block via two lines. Both the AE and the PS have earth terminals 'E'. A switchable link connects these earth terminals to the 'Generator return/Earth'. Text below the switch explains: 'Insert link to couple untested port to earth (normal operation)' and 'Remove link to decouple untested port from earth (terminated only)'. The diagram is labeled K.44(17)\_FA.5-15. + +**Figure A.5-15 – Terminating and coupling to earth of untested internal shielded cable ports** + +#### A.5.3.7 Internal d.c. power interface + +When an internal d.c. power port is the untested port, it is suggested that 3 mH be inserted in series with each line leg between the AE and the generator. A 115 V clamping device may be connected between each line leg and earth at the AE to further decouple the AE, see Figure A.5-16. This will limit the current conducted into the AE to a few amps for power feeding up to 100 V DC. Other values or methods, e.g., an artificial cable, are allowed. + +![Figure A.5-16: Terminating and coupling to earth of untested internal d.c. power interfaces ports. The figure contains two sub-diagrams, (a) and (b).](cac61a60141d0335b4ae7a081f6b18d4_img.jpg) + +Figure A.5-16 consists of two sub-diagrams, (a) and (b), illustrating the termination and coupling to earth of untested internal d.c. power interfaces. + +**a) Termination of an untested internal d.c. power port** + +This diagram shows a "Decoupling network" (dashed box) connected between an "EUT reference bar" and "Auxiliary equipment". The network contains two "3 mH" inductors in series with the power lines (dpf1 and dpf2). Each line also has a "115 V" clamping device connected to the reference bar. The auxiliary equipment has a ground connection labeled "E". + +**b) Coupling to earth and termination of an untested internal d.c. power port** + +This diagram shows a "Decoupling network" (dashed box) connected between a "Generator return/Earth" and "Auxiliary equipment". The network contains two "3 mH" inductors in series with the power lines (dpf1 and dpf2). Each line also has a "115 V" clamping device connected to the earth. The auxiliary equipment has a ground connection labeled "E". The text "K.44(17)\_FA.5-16" is present near the bottom right. + +Figure A.5-16: Terminating and coupling to earth of untested internal d.c. power interfaces ports. The figure contains two sub-diagrams, (a) and (b). + +**Figure A.5-16 – Terminating and coupling to earth of untested internal d.c. power interfaces ports** + +### A.5.4 Protection elements + +When performing the coordination test for a tested port to an untested external or internal port, it is necessary to install protection for the EUT on the external or internal port which is coupled to earth. + +#### A.5.4.1 External symmetric pair + +![Diagram of protection connection for an external symmetric pair port coupled to earth.](3766b291e69420b0437ae278b057b5ee_img.jpg) + +This diagram shows two horizontal lines labeled 'a' and 'b' representing the symmetric pair. A vertical line labeled 'EUT reference bar' is connected to the midpoint between 'a' and 'b'. A protection element, represented by a circle with a ground symbol, is connected between the midpoint and the 'EUT reference bar'. The text 'Protection for EUT' is above the protection element. The text 'To EUT' is to the left of the protection element, and 'To coupling-to-earth elements' is to the right. The identifier 'K.44(17)\_FA.5-17' is in the bottom right corner. + +Diagram of protection connection for an external symmetric pair port coupled to earth. + +Figure A.5-17 – Connection of protection for the untested external symmetric pair port coupled to earth + +#### A.5.4.2 External coaxial cable port + +![Diagram of protection connection for an external coaxial cable port coupled to earth.](50ef8602c7c9edd2da0e2133e772c2a2_img.jpg) + +This diagram shows a coaxial cable represented by two concentric circles. A vertical line labeled 'EUT reference bar' is connected to the center conductor. A protection element, represented by a circle with a gas discharge tube symbol, is connected between the center conductor and the 'EUT reference bar'. The text 'Protection for EUT' is above the protection element. The text 'To EUT' is to the left, and 'To coupling-to-earth elements' is to the right. The identifier 'K.44(17)\_FA.5-18' is in the bottom right corner. + +Diagram of protection connection for an external coaxial cable port coupled to earth. + +Figure A.5-18 – Connection of protection for the untested external coaxial cable port coupled to earth + +#### A.5.4.3 Dedicated power feed port + +![Diagram of protection connection for a dedicated power feed port coupled to earth.](ad555483986d7170a46ce72d164b5bc8_img.jpg) + +This diagram shows two horizontal lines labeled 'pvf1' and 'pvf2'. A vertical line labeled 'EUT reference bar' is connected to the midpoint between 'pvf1' and 'pvf2'. Two protection elements, each represented by a circle with a varistor symbol and labeled '125 V', are connected in series between the midpoint and the 'EUT reference bar'. The text 'Protection for EUT' is above the top protection element. The text 'To EUT' is to the left, and 'To coupling-to-earth elements' is to the right. The identifier 'K.44(17)\_FA.5-19' is in the bottom right corner. + +Diagram of protection connection for a dedicated power feed port coupled to earth. + +Figure A.5-19 – Connection of protection for the untested external dedicated power feed port coupled to earth + +#### A.5.4.4 Mains power port + +![Diagram of protection connection for a mains power port coupled to earth.](6b9ee906d502aece4a2becf5895db07a_img.jpg) + +This diagram shows two horizontal lines labeled 'L1' and 'N1'. A vertical line labeled 'EUT reference' is connected to the midpoint between 'L1' and 'N1'. A protection element, represented by a circle with a varistor symbol and labeled 'SP', is connected between the midpoint and the 'EUT reference'. The text 'Protection for EUT' is above the protection element. The text 'To' is to the left, and 'To coupling-to-earth elements' is to the right. The identifier 'K.44(17)\_FA.5-20' is in the bottom right corner. + +Diagram of protection connection for a mains power port coupled to earth. + +Figure A.5-20 – Connection of protection for the untested external mains power port coupled to earth + +## **A.6 Test schematics for different types of ports** + +### **A.6.1 Symmetric pair ports** + +Figures A.6.1-1a and A.6.1-1b give the schematic for applying transverse/differential surges. Figure A.6.1-2 gives the schematic for applying surges from port to earth. Figure A.6.1-3 gives the schematic for applying surges from an external port to an external port. Figure A.6.1-4 gives the schematic for applying surges to multiple external ports to earth. Figure A.6.1-5 gives the schematic for applying surges to multiple external ports to an external port. + +### **A.6.2 Coaxial ports** + +See Figures A.6.2-1, A.6.2-2 and A.6.2-3. + +### **A.6.3 a.c. or d.c. dedicated power feed ports** + +Figures A.6.3-1a and A.6.3-1b give the schematic for applying transverse/differential surges. Figure A.6.3-2 gives the schematic for applying surges from port to earth. Figure A.6.3-3 gives the schematic for applying surges from an external port to an external port. + +### **A.6.4 Mains power ports** + +Figure A.6.4-1 gives the schematic for applying transverse/differential surges. Figure A.6.4-2 gives the schematic for applying surges from port to earth. Figure A.6.4-3 gives the schematic for applying surges from an external port to an external port. + +### **A.6.5 Internal cable ports** + +See Figures A.6.5-1 and A.6.5-2. + +### **A.6.6 DC power ports** + +Figure A.6.6-1a gives a test circuit for applying a surge to the DC powered equipment port. Figure A.6.6-1b gives a test circuit for applying a surge to the DC power source equipment port. The increasing use of electronic control in power source ports necessitates surge resistibility testing. + +In Figures A.6.6-1a and A.6.6-1b, if the power supply system is floating a common-mode/port to earth surge results. When one polarity of the power supply system is bonded to earth the applied common-mode/port to earth surge automatically becomes a differential-mode/transverse surge due to the polarity bonding. Figure A.6.6-1a can also be used for internal port to internal port testing. + +### **A.6.7 Ethernet ports** + +Figure A.6.7-1 gives the termination and coupling network to earth for untested Ethernet ports. In Figure A.6.7-1 a), the series 10 $\Omega$ resistors are only an example. They could be replaced by an Ethernet cable of convenient length. Also, if the Ethernet ports on the AE have a low impedance to earth, it will be necessary to remove the earth connection from the AE and to use a floating PS to power the AE. This is to decouple the AE to prevent it conducting a surge current to earth. + +Figure A.6.7-2 gives the schematic for applying a transverse/differential impulse to test the impulse current withstand of the Mode A and Mode B PoE powering feeds. + +Figure A.6.7-3 gives the schematic for determining the d.c. insulation resistance and Figure A.6.7-3a provides the schematic for determining the Ethernet port rated impulse voltage. + +Figure A.6.7-4 provides additional information for Ethernet longitudinal/common mode surge testing. + +All tests on the Ethernet port except for the insulation resistance test are done in the powered condition but not operational. Ethernet port testing may be done in an unpowered condition when the EUT is a PoE powered device (PD), and the PoE power sourcing equipment (PSE), cannot sense the connected PD EUT. The coupling/decoupling network connected between the PSE and PD maximizes the surge + +level applied to the PD but may stop the correct operation of PSE load sensing, causing the PD to be unpowered. When the untested Ethernet port is coupled to earth, the Ethernet circuit will also be non-operational. The insulation resistance test is performed with the equipment unpowered. Subsequently the equipment must be tested in an operational state to verify it still meets its specification. + +![Figure A.6.1-1a: Example of a test circuit for a transverse/differential overvoltage or overcurrent on a single external symmetric pair port (a terminal to earth).](87c64bd7d33fca8b9b29228c80ddf175_img.jpg) + +The diagram illustrates a test circuit for a transverse/differential overvoltage or overcurrent on a single external symmetric pair port (a terminal to earth). The circuit consists of the following components and connections: + +- Test generator:** Located on the left, with terminals $O_1$ (Output), $O_2$ (Output), and Return (Generator return/Earth). The Return terminal is connected to earth. +- Powering, auxiliary equipment or terminations as required and decoupling networks (See Figure A.5-3):** A central block connected to the test generator. It has terminals $O_1$ , $O_2$ , and $E$ (Earth). +- Coupling element (See Table A.5-1):** Two dashed boxes representing coupling elements, one above and one below the central block, connected to the lines between the test generator and the central block. +- Special test protector when required for the test:** A dashed box containing a symbol for a test protector, connected in series with the lines between the central block and the EUT. +- Resistor $R_1$ :** Connected between the lines and the EUT reference bar. The text indicates $R_1 = 0 \Omega$ unless otherwise specified. +- EUT (Equipment Under Test):** A block with terminals $a$ , $b$ , $a_2$ , $b_2$ , and $E$ (Earth). It is connected to the lines via a "Int./Ext. ports" interface. +- EUT reference bar:** A horizontal bar connected to the $E$ terminal of the EUT and the $E$ terminal of the rightmost block. +- Powering, auxiliary equipment or terminations as required and decoupling networks (See Figures A.5-10 to A.5-16):** A block on the right, connected to the EUT reference bar and the lines. It has terminals $a$ , $b$ , $a_2$ , $b_2$ , and $E$ (Earth). + +Figure A.6.1-1a: Example of a test circuit for a transverse/differential overvoltage or overcurrent on a single external symmetric pair port (a terminal to earth). + +K.44(18)\_FA.6.1-1a + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.6.1-1a – Example of a test circuit for a transverse/differential overvoltage or overcurrent on a single external symmetric pair port (a terminal to earth)** + +![Figure A.6.1-1b: Example of a test circuit for a transverse/differential overvoltage or overcurrent on a single external symmetric pair port (b terminal to earth).](352d21d1e740e4a58cb17ab8656cfad8_img.jpg) + +The diagram illustrates a test circuit for a transverse/differential overvoltage or overcurrent on a single external symmetric pair port (b terminal to earth). The circuit consists of the following components and connections: + +- Test generator:** Located on the left, with terminals labeled $O_1$ , $O_2$ (Output), and Return. The Return terminal is connected to a common ground/earth point. +- Powering, auxiliary equipment, or terminations as required and decoupling networks (See Figure A.5-3):** A central block connected to the test generator's output. It has an earth terminal labeled $E$ . +- Coupling element (See Table A.5-1):** Two dashed boxes representing coupling elements, one above and one below the central block, connected to the lines between the test generator and the central block. +- Special test protector when required for the test:** A dashed box containing a symbol for a protector, connected in series with the lines leading to the EUT. +- Resistor $R_1$ :** Connected between the lines and the common ground/earth point. A label indicates $R_1 = 0 \Omega$ unless otherwise specified. +- EUT (Equipment Under Test):** A block with terminals labeled $a$ , $b$ , $a_2$ , and $b_2$ . The $b$ and $b_2$ terminals are connected to the lines from the special test protector. The $a$ and $a_2$ terminals are connected to the next block. The EUT also has an earth terminal labeled $E$ connected to the EUT reference bar. +- Int./Ext. ports:** A dashed box containing the $a$ , $b$ , $a_2$ , and $b_2$ terminals, indicating internal or external ports. +- Powering, auxiliary equipment or terminations as required and decoupling networks (See Figures A.5-10 to A.5-16):** A block on the far right connected to the EUT's $a$ and $a_2$ terminals. It also has an earth terminal labeled $E$ connected to the EUT reference bar. +- EUT reference bar:** A horizontal bar connecting the earth terminals of the EUT and the final block to the common ground/earth point. + +Figure A.6.1-1b: Example of a test circuit for a transverse/differential overvoltage or overcurrent on a single external symmetric pair port (b terminal to earth). + +K.44(18)\_FA.6.1-1b + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.6.1-1b – Example of a test circuit for a transverse/differential overvoltage or overcurrent on a single external symmetric pair port (b terminal to earth)** + +![Figure A.6.1-2: Example of a test circuit for an overvoltage or overcurrent on a single external symmetric pair port to earth. The diagram shows a test setup starting with an 8/20 test generator connected to an AC source or 10/700 test generator. The output of the AC source passes through current limiting resistors (R) to a pair of ports (O1, O2). These ports are connected to a 'Powering, auxiliary equipment or terminations as required and decoupling networks' block (See Figure A.5-3) via 'Coupling element' blocks (See Table A.5-1). A 'Special test protector, when required, for the test' is connected between the output and the 'EUT' (Equipment Under Test). The EUT has an 'Internal port coupled to earth' and 'Ext./Int. ports'. The EUT is connected to an 'EUT reference bar' through a resistor R1 (R1 = 0 Ω, unless otherwise specified). The EUT reference bar is connected to the 'Generator return/Earth' and to another 'Powering, auxiliary equipment or terminations' block (See Figures A.5-14 to A.5-16). The diagram is labeled K.44(17)_FA.6.1-2.](fd8f5da2b60cdca94896f3cde8ee81f0_img.jpg) + +Figure A.6.1-2: Example of a test circuit for an overvoltage or overcurrent on a single external symmetric pair port to earth. The diagram shows a test setup starting with an 8/20 test generator connected to an AC source or 10/700 test generator. The output of the AC source passes through current limiting resistors (R) to a pair of ports (O1, O2). These ports are connected to a 'Powering, auxiliary equipment or terminations as required and decoupling networks' block (See Figure A.5-3) via 'Coupling element' blocks (See Table A.5-1). A 'Special test protector, when required, for the test' is connected between the output and the 'EUT' (Equipment Under Test). The EUT has an 'Internal port coupled to earth' and 'Ext./Int. ports'. The EUT is connected to an 'EUT reference bar' through a resistor R1 (R1 = 0 Ω, unless otherwise specified). The EUT reference bar is connected to the 'Generator return/Earth' and to another 'Powering, auxiliary equipment or terminations' block (See Figures A.5-14 to A.5-16). The diagram is labeled K.44(17)\_FA.6.1-2. + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.6.1-2 – Example of a test circuit for an overvoltage or overcurrent on a single external symmetric pair port to earth** + +![A complex test circuit diagram for overvoltage or overcurrent testing. On the left, an '8/20 test generator' with terminals O1, O2, O3, O4, O5, O6 and a 'Return' terminal is connected to an 'AC source or 10/700 test generator' with 'Output' terminals O1, O2 and a 'Return' terminal. Both are connected to a common 'Generator return/Earth' ground. The AC source is connected to a 'Coupling element (See Table A.5-1)', which is in turn connected to 'Powering, auxiliary equipment or terminations as required and decoupling networks. (See Figure A.5-3)'. This network has terminals O1, O2, and E. A 'Special test protector when required for the test' is connected between the network's O1/O2 lines and the 'EUT' (Equipment Under Test). The EUT has an 'External port coupled to earth' (Ext. port) and 'Int./Ext. ports' labeled a, b, a2, b2, and E. A resistor R1 is connected between the network's O1/O2 lines and the 'EUT reference bar'. The EUT reference bar is connected to the EUT's E terminal and to another 'Powering, auxiliary equipment or terminations, as required, coupling-to-earth and decoupling networks. (See Figures A.5-10 to A.5-13)' which has an E terminal. A dashed box labeled 'Appropriate primary protection, or special test protector, when required for the test. (See Figures A.5-17 to A.5-20)' is connected between the EUT's Ext. port and the second network's E terminal. A note indicates 'R1 = 0 Ω, unless otherwise specified'. The diagram is labeled 'K.44(18)_FA.6.1-3'.](1b23b78336d8bd286c653cbdb38428dd_img.jpg) + +A complex test circuit diagram for overvoltage or overcurrent testing. On the left, an '8/20 test generator' with terminals O1, O2, O3, O4, O5, O6 and a 'Return' terminal is connected to an 'AC source or 10/700 test generator' with 'Output' terminals O1, O2 and a 'Return' terminal. Both are connected to a common 'Generator return/Earth' ground. The AC source is connected to a 'Coupling element (See Table A.5-1)', which is in turn connected to 'Powering, auxiliary equipment or terminations as required and decoupling networks. (See Figure A.5-3)'. This network has terminals O1, O2, and E. A 'Special test protector when required for the test' is connected between the network's O1/O2 lines and the 'EUT' (Equipment Under Test). The EUT has an 'External port coupled to earth' (Ext. port) and 'Int./Ext. ports' labeled a, b, a2, b2, and E. A resistor R1 is connected between the network's O1/O2 lines and the 'EUT reference bar'. The EUT reference bar is connected to the EUT's E terminal and to another 'Powering, auxiliary equipment or terminations, as required, coupling-to-earth and decoupling networks. (See Figures A.5-10 to A.5-13)' which has an E terminal. A dashed box labeled 'Appropriate primary protection, or special test protector, when required for the test. (See Figures A.5-17 to A.5-20)' is connected between the EUT's Ext. port and the second network's E terminal. A note indicates 'R1 = 0 Ω, unless otherwise specified'. The diagram is labeled 'K.44(18)\_FA.6.1-3'. + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.6.1-3 – Example of a test circuit for an overvoltage or overcurrent on a single external symmetric pair port to another external port** + +![Figure A.6.1-4: Example of a test circuit for an overvoltage or overcurrent on an external multiple symmetric pairs port, external multiple symmetric pair ports or a combination of both, to earth. The diagram shows a test setup where an 8/20 test generator and an AC source or 10/700 test generator are connected to current limiting resistors. These resistors are then connected to the EUT through coupling elements and powering/auxiliary equipment or terminations. The EUT is connected to an EUT reference bar, which is then connected to earth. The diagram also includes labels for 'Agreed primary protector when required for the test', 'Internal port coupled to earth', and 'Powering, auxiliary equipment or terminations, as required, coupling-to-earth and decoupling networks.'](15de63f0b5df62e6ab9164f2a72e2e33_img.jpg) + +The diagram illustrates a test circuit for overvoltage or overcurrent on external multiple symmetric pairs ports. On the left, an 8/20 test generator and an AC source or 10/700 test generator are shown. Their outputs (O1 to O6) are connected to a set of current limiting resistors (R). The resistors are connected to the EUT through coupling elements (labeled 'See Table A.5-1'). The EUT is connected to an EUT reference bar, which is then connected to earth. The diagram also includes labels for 'Agreed primary protector when required for the test', 'Internal port coupled to earth', and 'Powering, auxiliary equipment or terminations, as required, coupling-to-earth and decoupling networks.' The EUT has multiple ports: 'Ext. port', 'Int./Ext. ports', and 'Internal port coupled to earth'. The EUT reference bar is connected to earth via a ground symbol. + +Figure A.6.1-4: Example of a test circuit for an overvoltage or overcurrent on an external multiple symmetric pairs port, external multiple symmetric pair ports or a combination of both, to earth. The diagram shows a test setup where an 8/20 test generator and an AC source or 10/700 test generator are connected to current limiting resistors. These resistors are then connected to the EUT through coupling elements and powering/auxiliary equipment or terminations. The EUT is connected to an EUT reference bar, which is then connected to earth. The diagram also includes labels for 'Agreed primary protector when required for the test', 'Internal port coupled to earth', and 'Powering, auxiliary equipment or terminations, as required, coupling-to-earth and decoupling networks.' + +K.44(17)\_FA.6.1-4 + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.6.1-4 – Example of a test circuit for an overvoltage or overcurrent on an external multiple symmetric pairs port, external multiple symmetric pair ports or a combination of both, to earth** + +![Figure A.6.1-5: Example of test circuit for an overvoltage or overcurrent on an external multiple symmetric pairs port, external multiple symmetric pair ports or a combination of both, to another external port. The diagram shows a test setup with an 8/20 test generator, an AC source or 10/700 test generator, current limiting resistors, coupling elements, power networks, primary protectors, and the Equipment Under Test (EUT) connected to an EUT reference bar.](af6c3f383ddc0c142cdd7e186cc78199_img.jpg) + +The diagram illustrates a test circuit for overvoltage or overcurrent on external multiple symmetric pairs ports. On the left, an 8/20 test generator and an AC source or 10/700 test generator are connected to a set of current limiting resistors (R). The outputs of these resistors (O1, O2, O3, O4) are connected to the input ports (O1, O2, O3, O4) of the Equipment Under Test (EUT) through coupling elements (See Table A.5-1). The EUT has multiple ports: external ports (a, b, a2, b2), an external port coupled to earth, and internal/external ports. The EUT is connected to an EUT reference bar. The reference bar is connected to a power network (Powering, auxiliary equipment or terminations, as required, coupling-to-earth and decoupling networks. (See Figures A.5-10 to A.5-13)) and an appropriate primary protection or special test protector (See Figures A.5-17 to A.5-20). The power network is also connected to an agreed primary protector when required for the test. The EUT reference bar is also connected to the generator return/Earth. + +Figure A.6.1-5: Example of test circuit for an overvoltage or overcurrent on an external multiple symmetric pairs port, external multiple symmetric pair ports or a combination of both, to another external port. The diagram shows a test setup with an 8/20 test generator, an AC source or 10/700 test generator, current limiting resistors, coupling elements, power networks, primary protectors, and the Equipment Under Test (EUT) connected to an EUT reference bar. + +K.44(17)\_FA.6.1-5 + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.6.1-5 – Example of test circuit for an overvoltage or overcurrent on an external multiple symmetric pairs port, external multiple symmetric pair ports or a combination of both, to another external port** + +![Schematic diagram of a test circuit for differential overvoltage or overcurrent on an external coaxial cable port. The diagram shows an 8/20 test generator connected to a 1.2/50-8/20 test generator. The output of the second generator passes through current limiting resistors (R) and a coupling element (See Table A.5-1). The coupling element is connected to a coaxial cable, which is connected to the EUT (Equipment Under Test). The EUT has internal/external ports and an earth (E) connection. The EUT is connected to an EUT reference bar, which is connected to the earth. The diagram also includes a 'Special test protector, when required, for the test' and 'Powering, auxiliary equipment or terminations, as required and decoupling networks. (See Figure A.5-4)'. A note indicates that the 'Length of coaxial cable should be as short as practicable'. The diagram is labeled K.44(17)_FA.6.2-1.](6a7ea9d5162b0a0cfbd8d77c6cac90d1_img.jpg) + +Schematic diagram of a test circuit for differential overvoltage or overcurrent on an external coaxial cable port. The diagram shows an 8/20 test generator connected to a 1.2/50-8/20 test generator. The output of the second generator passes through current limiting resistors (R) and a coupling element (See Table A.5-1). The coupling element is connected to a coaxial cable, which is connected to the EUT (Equipment Under Test). The EUT has internal/external ports and an earth (E) connection. The EUT is connected to an EUT reference bar, which is connected to the earth. The diagram also includes a 'Special test protector, when required, for the test' and 'Powering, auxiliary equipment or terminations, as required and decoupling networks. (See Figure A.5-4)'. A note indicates that the 'Length of coaxial cable should be as short as practicable'. The diagram is labeled K.44(17)\_FA.6.2-1. + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.6.2-1 – Example of a test circuit for a differential overvoltage or overcurrent on an external coaxial cable port** + +![Schematic diagram of a test circuit for a lightning shield current test on an external coaxial cable port to earth. The diagram shows two 8/20 test generators connected to the EUT via a coaxial cable. The first generator (Note 2) has outputs O1-O6 and a Return. The second generator (Note 1) also has outputs O1-O6 and a Return. The EUT has internal ports coupled to earth, internal/external ports, and an earth (E) terminal. The EUT is connected to a reference bar, which is connected to the generator return/earth. The EUT is also connected to powering, auxiliary equipment or terminations, as required, and decoupling networks. The length of the coaxial cable should be as short as practicable. The diagram is labeled K.44(17)_FA.6.2-2.](99698c448635861b7dc8d352f87a1b2b_img.jpg) + +Length of coaxial cable should be as short as practicable + +Internal port coupled to earth + +EUT + +Int. ports + +Int./Ext. ports + +E + +Generator return/Earth + +EUT reference bar + +8/20 test generator (See Note 2) + +O1 O2 O3 O4 O5 O6 + +Return + +8/20 test generator (See Note 1) + +O1 O2 O3 O4 O5 O6 + +Return + +Powering, auxiliary equipment or terminations, as required, and decoupling networks. (See Figures A.5-14 to A.5-16) + +E + +K.44(17)\_FA.6.2-2 + +Schematic diagram of a test circuit for a lightning shield current test on an external coaxial cable port to earth. The diagram shows two 8/20 test generators connected to the EUT via a coaxial cable. The first generator (Note 2) has outputs O1-O6 and a Return. The second generator (Note 1) also has outputs O1-O6 and a Return. The EUT has internal ports coupled to earth, internal/external ports, and an earth (E) terminal. The EUT is connected to a reference bar, which is connected to the generator return/earth. The EUT is also connected to powering, auxiliary equipment or terminations, as required, and decoupling networks. The length of the coaxial cable should be as short as practicable. The diagram is labeled K.44(17)\_FA.6.2-2. + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +NOTE 1 – Output connections to be used for equipment designed to be connected to antennas/equipment exposed to direct lightning currents, e.g., connected to antennas/equipment mounted on a tower. + +NOTE 2 – Output connections to be used for applicable equipment not covered by Note 1. + +**Figure A.6.2-2 – Example of a test circuit for a lightning shield current test on an external coaxial cable port to earth** + +![Schematic diagram of a test circuit for a lightning shield current test. It shows two 8/20 test generators connected to an external coaxial cable, which is connected to the EUT. The EUT has internal ports coupled to earth and internal/external ports. The EUT is connected to an EUT reference bar, which is connected to the generator return/earth. The EUT is also connected to appropriate primary protection or special test protectors, and to powering, auxiliary equipment or terminations, as required, and coupling-to-earth and decoupling networks. The diagram includes labels for ports O1 through O6, Return, EUT, Int. ports, Int./Ext. ports, E, EUT reference bar, Generator return/Earth, and various notes and figures.](a4de02b04a1a8f6cb8121ac2e11bf95a_img.jpg) + +Length of coaxial cable should be as short as practicable + +Internal port coupled to earth + +Appropriate primary protection, or special test protector, when required for the test. (See Figures A.5-17 to A.5-20) + +Powering, auxiliary equipment or terminations, as required, and coupling-to-earth and decoupling networks. (See Figures A.5-10 to A.5-13) + +8/20 test generator (See Note 2) + +O1 O2 O3 O4 O5 O6 Return + +8/20 test generator (See Note 1) + +O1 O2 O3 O4 O5 O6 Return + +EUT + +Int. ports + +Int./Ext. ports + +E + +EUT reference bar + +Generator return/Earth + +K.44(17)\_FA.6.2-3 + +Schematic diagram of a test circuit for a lightning shield current test. It shows two 8/20 test generators connected to an external coaxial cable, which is connected to the EUT. The EUT has internal ports coupled to earth and internal/external ports. The EUT is connected to an EUT reference bar, which is connected to the generator return/earth. The EUT is also connected to appropriate primary protection or special test protectors, and to powering, auxiliary equipment or terminations, as required, and coupling-to-earth and decoupling networks. The diagram includes labels for ports O1 through O6, Return, EUT, Int. ports, Int./Ext. ports, E, EUT reference bar, Generator return/Earth, and various notes and figures. + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +NOTE 1 – Output connections to be used for equipment designed to be connected to antennas/equipment exposed to direct lightning currents, e.g., connected to antennas/equipment mounted on a tower. + +NOTE 2 – Output connections to be used for applicable equipment not covered by Note 1. + +**Figure A.6.2-3 – Example of a test circuit for a lightning shield current test on an external coaxial cable port to an external port** + +![Schematic diagram of a test circuit for a transverse/differential overvoltage or overcurrent on a single external dpf port (dpf2 earthed).](b20942bb14022381a243971ab9790dd9_img.jpg) + +The diagram illustrates a test circuit setup. On the left, a 'Test generator' has an 'Output' terminal connected to a 'Current limiting resistors' box containing two resistors labeled 'R'. The 'Return' terminal of the generator is connected to 'Generator return/Earth', which is grounded. The 'Output' terminal connects to a 'Powering, auxiliary equipment or terminations as required and decoupling networks. (See Figure A.5-5)' box. This box has two 'dpf' ports, 'dpf1' and 'dpf2', and an 'E' (earth) terminal. 'dpf1' is connected to a 'Coupling element (See Table A.5-1)'. 'dpf2' is connected to a 'Special test protector when required for the test' box, which contains two varistors. The 'E' terminal of the powering box is connected to the 'Generator return/Earth' line. The 'Special test protector' box is connected to an 'EUT' (Equipment Under Test) box. The 'EUT' box has 'Int./Ext. ports' for 'dpf1' and 'dpf2', an 'E' terminal, and an 'EUT reference bar'. The 'EUT reference bar' is connected to the 'Generator return/Earth' line. The 'Int./Ext. ports' are connected to another 'Powering, auxiliary equipment or terminations, as required, and decoupling networks. (See Figures A.5-10-A.5-16)' box, which has an 'E' terminal connected to the 'Generator return/Earth' line. A second 'Coupling element (see Table A.5-1)' is connected between the 'EUT reference bar' and the 'dpf1' port of the first 'Powering, auxiliary equipment or terminations' box. The diagram is labeled 'K.44(17)\_FA.6.3-1a' in the bottom right corner. + +Schematic diagram of a test circuit for a transverse/differential overvoltage or overcurrent on a single external dpf port (dpf2 earthed). + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.6.3-1a – Example of test circuit for a transverse/differential overvoltage or overcurrent on a single external dpf port (dpf2 earthed)** + +![Schematic diagram of a test circuit for a transverse/differential overvoltage or overcurrent on a single external dpf port (dpf1 earthed).](29043c6ca27a7cfbc757a5d2eb029d33_img.jpg) + +The diagram shows a test setup involving several interconnected blocks. On the far left, a "Test generator" has an "Output" and a "Return". The "Output" connects to a block labeled "Current limiting resistors R" containing two resistor symbols. The "Return" connects to a "Generator return/Earth" point. The resistors connect to a "Coupling element (See Table A.5-1)" which is part of a larger block labeled "Powering, auxiliary equipment or terminations as required and decoupling networks. (See Figure A.5-5)". This block has two output terminals, dpf1 and dpf2. Terminal dpf1 is connected to ground. Both terminals pass through a "Special test protector when required for the test" block, which contains gas discharge tube symbols, before reaching the "EUT" (Equipment Under Test). The EUT has terminals dpf1 and dpf2, and an earth terminal "E" connected to an "EUT reference bar". The EUT reference bar is also connected to the generator return/earth. To the right of the EUT, there are "Int./Ext. ports" connected via dashed lines to another block labeled "Powering, auxiliary equipment or terminations, as required, and decoupling networks. (See Figures A.5-10-A.5-16)", which also has an earth terminal "E" connected to the EUT reference bar. A second "Coupling element (see Table A.5-1)" is shown between the first powering block and the EUT reference bar. + +K.44(17)\_FA.6.3-1b + +Schematic diagram of a test circuit for a transverse/differential overvoltage or overcurrent on a single external dpf port (dpf1 earthed). + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.6.3-1b – Example of test circuit for a transverse/differential overvoltage or +overcurrent on a single external dpf port (dpf1 earthed)** + +![Figure A.6.3-2: Example of test circuit for an overvoltage or overcurrent on a single external dpf port to earth. The diagram shows a series of components connected in a test setup. From left to right: an 8/20 test generator with outputs O1 through O6 and a Return terminal; an AC source or 10/700 test generator with Output and Return terminals; current limiting resistors (R) connected between the AC source output and the Equipment Under Test (EUT); coupling elements (as per Table A.5-1) between the resistors and the EUT; a box for 'Powering, auxiliary equipment or terminations, as required and decoupling networks' (as per Figure A.5-5) connected to the EUT's dpf1 and dpf2 ports and earth (E); a 'Special test protector when required for the test' connected between the dpf ports and earth; the EUT itself, which has an 'Internal port coupled to earth' and 'Int./Ext. ports'; and a final box for 'Powering, auxiliary equipment or terminations, as required, coupling-to-earth and decoupling networks' (as per Figures A.5-14 to A.5-16) connected to the EUT's ports and earth. All earth connections lead to a common 'EUT reference bar' and then to 'Generator return/Earth'.](8c3eb53c927f55acd19723cfcd0c43b6_img.jpg) + +Figure A.6.3-2: Example of test circuit for an overvoltage or overcurrent on a single external dpf port to earth. The diagram shows a series of components connected in a test setup. From left to right: an 8/20 test generator with outputs O1 through O6 and a Return terminal; an AC source or 10/700 test generator with Output and Return terminals; current limiting resistors (R) connected between the AC source output and the Equipment Under Test (EUT); coupling elements (as per Table A.5-1) between the resistors and the EUT; a box for 'Powering, auxiliary equipment or terminations, as required and decoupling networks' (as per Figure A.5-5) connected to the EUT's dpf1 and dpf2 ports and earth (E); a 'Special test protector when required for the test' connected between the dpf ports and earth; the EUT itself, which has an 'Internal port coupled to earth' and 'Int./Ext. ports'; and a final box for 'Powering, auxiliary equipment or terminations, as required, coupling-to-earth and decoupling networks' (as per Figures A.5-14 to A.5-16) connected to the EUT's ports and earth. All earth connections lead to a common 'EUT reference bar' and then to 'Generator return/Earth'. + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.6.3-2 – Example of test circuit for an overvoltage or overcurrent on a single external dpf port to earth** + +![Figure A.6.3-3: Example of test circuit for an overvoltage or overcurrent on a single external dpf port to external port. The diagram shows a series of components connected in a test setup. From left to right: an 8/20 test generator with outputs O1 through O6 and a return; an AC source or 10/700 test generator with output and return; current limiting resistors (R) connected between the AC source output and the equipment under test (EUT); the EUT itself, which includes a 'Powering, auxiliary equipment or terminations as required and decoupling networks' block, 'Coupling element (See Table A.5-1)' blocks, and 'Special test protector when required for the test' blocks; an 'Appropriate primary protection, or special test protector' block; and finally, another 'Powering, auxiliary equipment or terminations' block. Various ports are labeled, including dpf1, dpf2, Ext. port, and Int./Ext. ports. A common 'EUT reference bar' is connected to the 'Generator return/Earth' and the 'Return' of the AC source. Notes indicate connections for cable screens and specific figures for different test scenarios.](e2dad48ec062e71202459a9ab82261e4_img.jpg) + +Figure A.6.3-3: Example of test circuit for an overvoltage or overcurrent on a single external dpf port to external port. The diagram shows a series of components connected in a test setup. From left to right: an 8/20 test generator with outputs O1 through O6 and a return; an AC source or 10/700 test generator with output and return; current limiting resistors (R) connected between the AC source output and the equipment under test (EUT); the EUT itself, which includes a 'Powering, auxiliary equipment or terminations as required and decoupling networks' block, 'Coupling element (See Table A.5-1)' blocks, and 'Special test protector when required for the test' blocks; an 'Appropriate primary protection, or special test protector' block; and finally, another 'Powering, auxiliary equipment or terminations' block. Various ports are labeled, including dpf1, dpf2, Ext. port, and Int./Ext. ports. A common 'EUT reference bar' is connected to the 'Generator return/Earth' and the 'Return' of the AC source. Notes indicate connections for cable screens and specific figures for different test scenarios. + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.6.3-3 – Example of test circuit for an overvoltage or overcurrent on a single external dpf port to external port** + +![Schematic diagram of a test circuit for transverse/differential overvoltage or overcurrent on an external mains port. The circuit includes a Test generator with Output and Return terminals. The Return terminal is connected to a Generator return/Earth point. The Output terminal is connected to a 'Current limiting resistors' block containing two resistors labeled 'R'. This is followed by a 'Coupling element (See Table A.5-1)'. The next stage is a 'Decoupling network (See Figure A.5-6)' which has an input labeled '230 V' with terminals 'L2' and 'N2'. A '(Note)' is placed near this network. The output of the decoupling network connects to a 'Primary protection when required for the test' block containing a varistor. This is followed by the 'EUT' (Equipment Under Test) which has 'Int./Ext. ports' labeled 'L1', 'N1', and 'E'. The 'E' terminal is connected to an 'EUT reference bar'. To the right, a box labeled 'Powering, auxiliary equipment or terminations, as required, and decoupling networks. (See Figures A.5-10-A.5-16)' is connected to the EUT's 'Int./Ext. ports' and has its own 'E' terminal connected to the EUT reference bar. The diagram is labeled 'K.44(17)_FA.6.4-1'.](3bf1696c3034743b5ab07a0b5e398347_img.jpg) + +Schematic diagram of a test circuit for transverse/differential overvoltage or overcurrent on an external mains port. The circuit includes a Test generator with Output and Return terminals. The Return terminal is connected to a Generator return/Earth point. The Output terminal is connected to a 'Current limiting resistors' block containing two resistors labeled 'R'. This is followed by a 'Coupling element (See Table A.5-1)'. The next stage is a 'Decoupling network (See Figure A.5-6)' which has an input labeled '230 V' with terminals 'L2' and 'N2'. A '(Note)' is placed near this network. The output of the decoupling network connects to a 'Primary protection when required for the test' block containing a varistor. This is followed by the 'EUT' (Equipment Under Test) which has 'Int./Ext. ports' labeled 'L1', 'N1', and 'E'. The 'E' terminal is connected to an 'EUT reference bar'. To the right, a box labeled 'Powering, auxiliary equipment or terminations, as required, and decoupling networks. (See Figures A.5-10-A.5-16)' is connected to the EUT's 'Int./Ext. ports' and has its own 'E' terminal connected to the EUT reference bar. The diagram is labeled 'K.44(17)\_FA.6.4-1'. + +NOTE – Total lead length, per SPD, to connect the primary protection shall be one metre + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.6.4-1 – Example of test circuit for a transverse/differential overvoltage or overcurrent on an external mains port** + +![Circuit diagram for overvoltage, overcurrent, and neutral potential rise testing. A test generator is connected to current limiting resistors (R) and a coupling element. A 230V source is connected to a decoupling network (L2, N2). The circuit includes primary protection, an EUT (Equipment Under Test) with internal ports coupled to earth, and various auxiliary equipment and terminations connected to an EUT reference bar. The diagram is labeled K.44(17)_FA.6.4-2.](32d36dfe7dc75b7c63f8edf0f28e4009_img.jpg) + +The diagram illustrates a test circuit for overvoltage, overcurrent, and rise of neutral potential. On the left, a 'Test generator' has 'Output' and 'Return' terminals. The 'Return' terminal is connected to 'Generator return/Earth' and grounded. The 'Output' terminal connects to a box labeled 'Current limiting resistors' containing two resistors 'R'. This is followed by a 'Coupling element (See Table A.5-1)'. A 230V AC source is connected between lines 'L2' and 'N2' and is part of a 'Decoupling network (See Figure A.5-6)'. A dashed box labeled '(Note 1)' encloses the coupling element and decoupling network. The circuit then passes through 'Primary protection when required for the test', represented by two varistors. The 'EUT' (Equipment Under Test) has three external ports: 'L1', 'N1', and 'E'. An arrow points to the 'E' port with the label 'Internal port coupled to earth'. The 'EUT' also has internal ports: 'Int. port', 'Int./Ext. ports', and 'E'. These internal ports are connected to a box labeled 'Powering, auxiliary equipment or terminations, as required, coupling-to-earth and decoupling networks. (See Figures A.5-14-A.5-16)'. The 'EUT reference bar' is connected to the 'E' port of the EUT and to the 'E' terminal of another box labeled 'Powering, auxiliary equipment or terminations, as required, and decoupling networks. (See Figures A.5-10-A.5-16)'. The entire system is referenced to the 'EUT reference bar'. + +Circuit diagram for overvoltage, overcurrent, and neutral potential rise testing. A test generator is connected to current limiting resistors (R) and a coupling element. A 230V source is connected to a decoupling network (L2, N2). The circuit includes primary protection, an EUT (Equipment Under Test) with internal ports coupled to earth, and various auxiliary equipment and terminations connected to an EUT reference bar. The diagram is labeled K.44(17)\_FA.6.4-2. + +NOTE 1 – Total lead length, per SPD, to connect the primary protection shall be one metre + +EUT earthing is as follows : + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.6.4-2 – Example of test circuit for an overvoltage, overcurrent and rise of neutral potential on an external mains port to earth** + +![Figure A.6.4-3: Example of test circuit for an overvoltage, overcurrent and rise of neutral potential on an external mains port to external port. The diagram illustrates a test generator with 'Output' and 'Return' terminals. The 'Output' connects to 'Current limiting resistors' (R). This is followed by a 'Coupling element' (referencing Table A.5-1). A 'Decoupling network' (referencing Figure A.5-6) is shown with a 230 V AC source, lines L2, N2, and PE2. 'Primary protection' is included when required. The EUT (Equipment Under Test) has an 'Ext. port' coupled to earth and 'Int./Ext. ports'. The 'Ext. port' is connected to 'Appropriate primary protection' (referencing Figures A.5-17 to A.5-20) and then to 'Powering, auxiliary equipment or terminations'. The 'Int./Ext. ports' also connect to auxiliary equipment. The EUT and auxiliary equipment are connected to an 'EUT reference bar' through resistor R1. The 'Return' from the test generator is connected to the 'Generator return/Earth' and the EUT reference bar.](c6212a3b14736d6a8c81ace75ae94ccf_img.jpg) + +External port coupled to earth + +EUT + +Ext. port + +Appropriate primary protection, or special test protector, when required for the test. (See Figures A.5-17-A.5-20) + +Powering, auxiliary equipment or terminations, as required, coupling-to-earth and decoupling networks. (See Figures A.5-10-A.5-13) + +Current limiting resistors + +$R$ + +Coupling element (See Table A.5-1) + +Primary protection when required for the test + +Decoupling network (See Figure A.5-6) + +$L_2$ + +230 V + +$N_2$ + +$PE_2$ + +(Note) + +Output + +Test generator + +Return + +Generator return/Earth + +$L_1$ + +$N_1$ + +Int./Ext. ports + +Powering, auxiliary equipment or terminations, as required, and decoupling networks. (See Figures A.5-10-A.5-16) + +$E$ + +$R_1$ + +EUT reference bar + +$R_1 = 0$ ohm, unless otherwise specified + +K.44(17)\_FA.6.4-3 + +Figure A.6.4-3: Example of test circuit for an overvoltage, overcurrent and rise of neutral potential on an external mains port to external port. The diagram illustrates a test generator with 'Output' and 'Return' terminals. The 'Output' connects to 'Current limiting resistors' (R). This is followed by a 'Coupling element' (referencing Table A.5-1). A 'Decoupling network' (referencing Figure A.5-6) is shown with a 230 V AC source, lines L2, N2, and PE2. 'Primary protection' is included when required. The EUT (Equipment Under Test) has an 'Ext. port' coupled to earth and 'Int./Ext. ports'. The 'Ext. port' is connected to 'Appropriate primary protection' (referencing Figures A.5-17 to A.5-20) and then to 'Powering, auxiliary equipment or terminations'. The 'Int./Ext. ports' also connect to auxiliary equipment. The EUT and auxiliary equipment are connected to an 'EUT reference bar' through resistor R1. The 'Return' from the test generator is connected to the 'Generator return/Earth' and the EUT reference bar. + +NOTE – Total lead length, per SPD, to connect the primary protection shall be one metre + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.6.4-3 – Example of test circuit for an overvoltage, overcurrent and rise of neutral potential on an external mains port to external port** + +![Figure A.6.5-1: Example of test circuit for an overvoltage or overcurrent on an internal port connected to an unshielded cable with single or multiple symmetric pairs to earth.](f78d2e126f00fcc5d8d9797ca410cc09_img.jpg) + +The diagram illustrates a test setup for overvoltage or overcurrent testing. On the left, a 'Test generator' has 'Output' and 'Return' terminals. The 'Output' is connected to a set of four 'Current limiting resistors' labeled 'R'. These resistors lead into a block labeled 'Powering, auxiliary equipment or terminations as required and decoupling networks. (See Figure A.5-7)'. This block has an earthing point 'E' connected to a common 'Generator return/Earth' line. From this block, four lines (labeled a, b, an, bn) pass through 'Coupling element (See Table A.5-1)' blocks to reach the 'EUT and terminations' block. The 'EUT and terminations' block includes an 'Internal port coupled to earth' and 'Int. port' connections. It also has 'Int./Ext. ports' which connect to another 'Powering, auxiliary equipment or terminations' block. This second block also has an earthing point 'E' connected to the 'EUT reference bar'. A third 'Powering, auxiliary equipment or terminations' block is shown on the far right, also with an earthing point 'E' and connections to the 'Int. port'. The 'EUT and terminations' block is connected to an 'EUT reference bar', which in turn is connected to the 'Generator return/Earth' line. The diagram includes various labels like 'K.44(17)\_FA.6.5-1' at the bottom right of the circuit. + +Figure A.6.5-1: Example of test circuit for an overvoltage or overcurrent on an internal port connected to an unshielded cable with single or multiple symmetric pairs to earth. + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.6.5-1 – Example of test circuit for an overvoltage or overcurrent on an internal port +connected to an unshielded cable with single or multiple symmetric pairs to earth** + +![Figure A.6.5-2: Example of a test circuit for an overvoltage or overcurrent on an internal port connected to a shielded cable to earth. The diagram shows a test generator connected to current limiting resistors (R) and a coupling element. A shielded cable of length L = 20 m connects the coupling element to the EUT (Equipment Under Test). The EUT has internal ports 1 to n, one of which is coupled to earth. The EUT is connected to an EUT reference bar, which is connected to the generator return/earth. Auxiliary equipment or terminations are connected to the EUT via decoupling networks. The diagram is labeled K.44(17)_FA.6.5-2.](e404de9a69c05473fbd6af28ee32311b_img.jpg) + +The diagram illustrates a test circuit for overvoltage or overcurrent on an internal port of an EUT connected to a shielded cable. On the left, a 'Test generator' has its 'Output' connected to a box labeled 'Current limiting resistors' containing a resistor 'R'. The 'Return' terminal of the generator is connected to 'Earth'. The output of the resistors connects to a 'Coupling element (See Table A.5-1)'. This is followed by a shielded cable of length $L = 20\text{ m}$ . The cable's conductors connect to ports '1' through 'n' on the 'EUT'. An arrow points to one of these ports with the label 'Internal port coupled to earth'. The EUT also has 'Int./Ext. ports' and an earthing point 'E'. All these are connected to a common 'EUT reference bar'. The reference bar is connected to the 'Generator return/Earth' line. To the right, a box labeled 'Powering, auxiliary equipment or terminations, as required, and decoupling networks. (See Figures A.5-10-A.5-16)' is connected to the EUT's ports and has its own earthing point 'E' connected to the reference bar. A final box on the far right, 'Powering, auxiliary equipment or terminations, as required, and decoupling networks. (See Figures A.5-14-A.5-16)', is also connected to the reference bar. The diagram is identified by the code 'K.44(17)\_FA.6.5-2'. + +Figure A.6.5-2: Example of a test circuit for an overvoltage or overcurrent on an internal port connected to a shielded cable to earth. The diagram shows a test generator connected to current limiting resistors (R) and a coupling element. A shielded cable of length L = 20 m connects the coupling element to the EUT (Equipment Under Test). The EUT has internal ports 1 to n, one of which is coupled to earth. The EUT is connected to an EUT reference bar, which is connected to the generator return/earth. Auxiliary equipment or terminations are connected to the EUT via decoupling networks. The diagram is labeled K.44(17)\_FA.6.5-2. + +For repeatability of measurement, it is recommended that the test be performed on an earth reference plane, with the cable laid on the ground plane in a snake pattern. All conductors are connected together and with the shield. (Reason: in worst case, inserted protective elements in the auxiliary equipment – not included in this test set-up – can cause short circuit termination.) + +EUT earthing is as follows: + +- 1) If the equipment has an earthing point, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing point, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing point nor a conductive case, let the equipment float. + +**Figure A.6.5-2 – Example of a test circuit for an overvoltage or overcurrent on an internal port connected to a shielded cable to earth** + +![Circuit diagram of a DC power interface for surge testing. A surge generator (Figure A.3-5) is connected via its output and return terminals to two coupling elements. Each coupling element contains a capacitor (C1a, C1b) and a resistor (R1a, R1b). The output of the coupling elements connects to the DC power source equipment. The DC power source equipment has an external electricity feed and a DC supply feed cable. The DC supply feed cable contains a decoupling network (Figure A.5-9) with inductors L1 and L2. The DC supply feed cable connects to the DC powered equipment. The DC powered equipment has internal/external ports and is connected to a powering, auxiliary equipment or terminations, as required, and decoupling networks (See Figures A.5-10 to A.5-16). The DC powered equipment is also connected to an EUT reference bar, which is connected to the generator return/earth.](24ba47df8be44ae91945d88ce2232df5_img.jpg) + +Circuit diagram of a DC power interface for surge testing. A surge generator (Figure A.3-5) is connected via its output and return terminals to two coupling elements. Each coupling element contains a capacitor (C1a, C1b) and a resistor (R1a, R1b). The output of the coupling elements connects to the DC power source equipment. The DC power source equipment has an external electricity feed and a DC supply feed cable. The DC supply feed cable contains a decoupling network (Figure A.5-9) with inductors L1 and L2. The DC supply feed cable connects to the DC powered equipment. The DC powered equipment has internal/external ports and is connected to a powering, auxiliary equipment or terminations, as required, and decoupling networks (See Figures A.5-10 to A.5-16). The DC powered equipment is also connected to an EUT reference bar, which is connected to the generator return/earth. + +K44(18)\_FA.6.6-1a + +DC powered equipment and DC power source equipment earth bonding is as follows: + +- 1) If the equipment has an earthing connection, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing connection, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing connection nor a conductive case, let the item float. +- 4) If the equipment is intended to bond one of the DC supply polarities to the local earthing system that connection must be made. +- 5) A common-mode surge is applied to the DC supply, but if one polarity is bonded to earth the applied surge automatically becomes a differential-mode/transverse surge. + +External electricity feed + +Some DC power source equipment requires an external electricity supply for power. + +Coupling network + +$C1a = C1b = 9 \mu\text{F}$ , 2 kV + +$R1a = R1b = 10 \Omega$ + +Cable inductance + +$L1 = L2 = 3 \text{ mH}$ maximum or specifically $2.5 \times l_m \mu\text{H}$ , where $l_m$ is the maximum cable length in m, or a commercial surge generator power decoupling network may be used. + +**Figure A.6.6-1a – DC power interface – Example of a surge test circuit for the DC powered equipment port** + +![Circuit diagram of a DC power interface surge test setup. A surge generator (Figure A.3-5) is connected to a DC power source equipment via two coupling elements (C1a, R1a and C1b, R1b). The DC power source equipment has an external electricity feed and DC output terminals (+Vo, -Vo, E). These terminals are connected to a DC supply feed cable (Figure A.5-9) containing a decoupling network with inductors L1 and L2. The cable connects to DC powered equipment with internal/external ports and an EUT reference bar. The EUT reference bar is connected to a powering, auxiliary equipment or termination network. The surge generator's return is connected to the EUT reference bar and earthed.](0adfaa8c2562a9fe3a8a96165d7d59a3_img.jpg) + +Circuit diagram of a DC power interface surge test setup. A surge generator (Figure A.3-5) is connected to a DC power source equipment via two coupling elements (C1a, R1a and C1b, R1b). The DC power source equipment has an external electricity feed and DC output terminals (+Vo, -Vo, E). These terminals are connected to a DC supply feed cable (Figure A.5-9) containing a decoupling network with inductors L1 and L2. The cable connects to DC powered equipment with internal/external ports and an EUT reference bar. The EUT reference bar is connected to a powering, auxiliary equipment or termination network. The surge generator's return is connected to the EUT reference bar and earthed. + +K44(18)\_FA.6.6-1b + +DC powered equipment and DC power source equipment earth bonding is as follows: + +- 1) If the equipment has an earthing connection, connect this point to the EUT reference bar; +- 2) If the equipment has a conductive case, but does not have an earthing connection, connect the case to the EUT reference bar; +- 3) If the equipment has neither an earthing connection nor a conductive case, let the item float. +- 4) If the equipment is intended to bond one of the DC supply polarities to the local earthing system that connection must be made. +- 5) A common-mode surge is applied to the DC supply, but if one polarity is bonded to earth the applied surge automatically becomes a differential-mode/transverse surge. + +External electricity feed + +Some DC power source equipment requires an external electricity supply for power. + +Coupling network + +$C1a = C1b = 9 \mu\text{F}$ , 2 kV + +$R1a = R1b = 10 \Omega$ + +Cable inductance + +$L1 = L2 = 3 \text{ mH}$ maximum or specifically $2.5 \times l_m \mu\text{H}$ , where $l_m$ is the maximum cable length in m, or a commercial surge generator power decoupling network may be used. + +**Figure A.6.6-1b – DC power interface – Example of a surge test circuit for the DC power source equipment port** + +![Diagram (a) showing the Ethernet coupling circuit from the EUT. It features a dashed box labeled 'Coupling/decoupling circuit' containing eight 10 Ω resistors. These resistors connect terminals 10, 20, 30, 60, 40, 50, 70, and 80 to the corresponding pins 1, 2, 3, 6, 4, 5, 7, and 8 of a block labeled 'Auxillary equipment'. A line labeled 'EUT reference bar' connects to the bottom of the coupling circuit box, and a terminal labeled 'E' is shown on the auxiliary equipment block.](5e05915b2a93a3b404422e0966a7c924_img.jpg) + +Diagram (a) showing the Ethernet coupling circuit from the EUT. It features a dashed box labeled 'Coupling/decoupling circuit' containing eight 10 Ω resistors. These resistors connect terminals 10, 20, 30, 60, 40, 50, 70, and 80 to the corresponding pins 1, 2, 3, 6, 4, 5, 7, and 8 of a block labeled 'Auxillary equipment'. A line labeled 'EUT reference bar' connects to the bottom of the coupling circuit box, and a terminal labeled 'E' is shown on the auxiliary equipment block. + +a) Ethernet coupling circuit from the EUT + +![Diagram (b) showing the termination circuit for an untested Ethernet port. It features a dashed box labeled 'Termination circuit' containing four 10 Ω resistors. These resistors are connected between pairs of terminals: 10 and 20, 30 and 60, 40 and 50, and 70 and 80.](d510bddda14c44163bbeee33b491a105_img.jpg) + +Diagram (b) showing the termination circuit for an untested Ethernet port. It features a dashed box labeled 'Termination circuit' containing four 10 Ω resistors. These resistors are connected between pairs of terminals: 10 and 20, 30 and 60, 40 and 50, and 70 and 80. + +b) Termination circuit for an untested Ethernet port + +**Figure A.6.7-1 – Termination and coupling to earth of untested Ethernet ports** + +![Figure A.6.7-2: PoE port powering pair transverse/differential surge test circuit. The diagram shows a 1.2/50-8/20 combination wave generator connected to a series current limiting resistor (R1) and an optional shunt resistor (R2). A switch (SW) can be set to position A (for PoE Mode A, terminals 1/2-3/6) or position B (for PoE Mode B, terminals 4/5-7/8). The generator return is connected to the EUT reference bar at point 'a'. The EUT contains a transformer-isolated port with 8 pins (1-8), a screen, a power port, and other ports. The EUT reference bar is connected to the screen at 'a', protective earth at 'b', and other signal ports at 'c' to 'd' via termination and decoupling components. The label K.44(18)_FA.6.7-2 is present.](caeb1637753f79f4cd005eda3768d1d5_img.jpg) + +Figure A.6.7-2: PoE port powering pair transverse/differential surge test circuit. The diagram shows a 1.2/50-8/20 combination wave generator connected to a series current limiting resistor (R1) and an optional shunt resistor (R2). A switch (SW) can be set to position A (for PoE Mode A, terminals 1/2-3/6) or position B (for PoE Mode B, terminals 4/5-7/8). The generator return is connected to the EUT reference bar at point 'a'. The EUT contains a transformer-isolated port with 8 pins (1-8), a screen, a power port, and other ports. The EUT reference bar is connected to the screen at 'a', protective earth at 'b', and other signal ports at 'c' to 'd' via termination and decoupling components. The label K.44(18)\_FA.6.7-2 is present. + +SW in position A: Test PoE Mode A powering terminals 1/2-3/6 + +SW in position B: Test PoE Mode B powering terminals 4/5-7/8 + +a = RJ45 screen cable connection + +b = EUT protective or functional earth connection + +c to d = Terminals of all other signal ports + +1, 2, 3, 4, 5, 6, 7 and 8 are Ethernet RJ45 pin numbers + +R = series current limiting resistor + +R1 = optional shunt resistor + +NOTE – For PSE, midspan power insertion equipment and PD ports, test in switch (SW) positions A and B. If the power sourcing equipment specifies the powering pairs, then the testing is only done on those pairs. + +**Figure A.6.7-2 – PoE port powering pair transverse/differential surge test circuit** + +![Figure A.6.7-3: Ethernet port, including PoE variants, d.c. insulation resistance test circuit. The diagram shows a DC test voltage (U_DC) applied through a switch (SW) and an ammeter (A) to measure leakage current (I_L). The ammeter is connected to the transformer-isolated port pins (1-8). The EUT reference bar is connected to the screen at 'a', protective earth at 'b', other signal ports at 'c' to 'd', and power port terminals at 'e'. The label K.44(18)_FA.6.7-3 is present.](e6d2a5fe2df965cbe598f8ea80fbb7d6_img.jpg) + +Figure A.6.7-3: Ethernet port, including PoE variants, d.c. insulation resistance test circuit. The diagram shows a DC test voltage (U\_DC) applied through a switch (SW) and an ammeter (A) to measure leakage current (I\_L). The ammeter is connected to the transformer-isolated port pins (1-8). The EUT reference bar is connected to the screen at 'a', protective earth at 'b', other signal ports at 'c' to 'd', and power port terminals at 'e'. The label K.44(18)\_FA.6.7-3 is present. + +$U_{DC}$ = DC test voltage (limited to 100 mA) + +SW = Switch closed for current measurement + +A = A meter used to measure leakage current, $I_L$ + +Insulation resistance = $U_{DC}/I_L$ + +Secondary circuit reference node connections if available: + +a = RJ45 screen cable connection + +b = EUT protective or functional earth connection + +c to d = terminals of all other signal ports + +e = Power port terminals + +**Figure A.6.7-3 – Ethernet port, including PoE variants, d.c. insulation resistance test circuit** + +![Circuit diagram for Ethernet port longitudinal/common mode withstand test. It shows an EUT connected to a 1.2/50-8/20 combination wave generator via a coupling network with a resistor R. The EUT's Ethernet port pins 1-8 and screen are connected to the generator's return/earth through an EUT reference bar at point 'a'. The EUT's power port is connected to a power source, with its earth terminal 'E' connected to the reference bar at point 'b'. Other signal ports are connected to the reference bar through termination and decoupling at points 'c' and 'd'. The reference bar extends to point 'e'.](5cc4a2ef554f31ea0577731931007fff_img.jpg) + +Circuit diagram for Ethernet port longitudinal/common mode withstand test. It shows an EUT connected to a 1.2/50-8/20 combination wave generator via a coupling network with a resistor R. The EUT's Ethernet port pins 1-8 and screen are connected to the generator's return/earth through an EUT reference bar at point 'a'. The EUT's power port is connected to a power source, with its earth terminal 'E' connected to the reference bar at point 'b'. Other signal ports are connected to the reference bar through termination and decoupling at points 'c' and 'd'. The reference bar extends to point 'e'. + +K.44(17)\_FA.6.7-3a + +- 1, 2, 3, 4, 5, 6, 7 and 8 are Ethernet RJ45 pin numbers +- a = RJ45 screen cable connection for STPE connections +- b = EUT protective or functional earth connection +- c to d = Terminals of all other signal ports + +NOTE – This circuit shorts out an injector device or power sourcing equipment power supply. IEEE 802.3 compliant power supplies will not be damaged by this condition. + +**Figure A.6.7-3a – Ethernet port, including PoE variants, longitudinal/common mode withstand test circuit** + +![Circuit diagram of an Ethernet port surge test setup. A 1.2/50-8/20 combination wave generator is connected to a coupling network. The coupling network consists of eight resistors (R) connected to pins 1 through 8 of an Ethernet port on an EUT. The generator's return/earth is connected to a common reference bar at point 'a'. The EUT's screen is also connected to this bar at point 'a'. The EUT has a power port connected to a power source, with an earth connection 'E' at point 'b'. Other signal ports on the EUT are connected to a 'Termination and decoupling' network, which is connected to the reference bar at points 'c' and 'd'. The reference bar extends to point 'e'.](d546a282ce562b4930a36fcf2ec3e7b3_img.jpg) + +Circuit diagram of an Ethernet port surge test setup. A 1.2/50-8/20 combination wave generator is connected to a coupling network. The coupling network consists of eight resistors (R) connected to pins 1 through 8 of an Ethernet port on an EUT. The generator's return/earth is connected to a common reference bar at point 'a'. The EUT's screen is also connected to this bar at point 'a'. The EUT has a power port connected to a power source, with an earth connection 'E' at point 'b'. Other signal ports on the EUT are connected to a 'Termination and decoupling' network, which is connected to the reference bar at points 'c' and 'd'. The reference bar extends to point 'e'. + +K.44(17)\_FA.6.7-4 + +- 1, 2, 3, 4, 5, 6, 7 and 8 are Ethernet RJ45 pin numbers +- a = RJ45 screen cable connection for STPE connections +- b = EUT protective or functional earth connection +- c to d = Terminals of all other signal ports + +**Figure A.6.7-4 – Ethernet port, including PoE variants, longitudinal/common mode to transverse/differential mode conversion surge test circuit** + +![Circuit diagram for twisted pair transverse/differential surge test. A 1.2/50-8/20 combination wave generator is connected to a coupling network (R1, C1, R2) which shortens impulse duration. The network is connected via switches (SW1, SW2, SWn) to terminal pairs (1a+1b, 2a+2b, na+nb) of the EUT. The EUT has a power port connected to a power source, other ports, and a termination and decoupling network. A reference bar is connected to the EUT's protective or functional earth (b) and the generator return. The diagram is labeled K.44(19)_FA.6.7-5.](e8f5117fb031f413a836525061addd61_img.jpg) + +Circuit diagram for twisted pair transverse/differential surge test. A 1.2/50-8/20 combination wave generator is connected to a coupling network (R1, C1, R2) which shortens impulse duration. The network is connected via switches (SW1, SW2, SWn) to terminal pairs (1a+1b, 2a+2b, na+nb) of the EUT. The EUT has a power port connected to a power source, other ports, and a termination and decoupling network. A reference bar is connected to the EUT's protective or functional earth (b) and the generator return. The diagram is labeled K.44(19)\_FA.6.7-5. + +K.44(19)\_FA.6.7-5 + +Twisted pair terminal pairs are 1a + 1b, 2a + 2b through to na + nb served by switches SW1, SW2 through to SWn, respectively. For each terminal pair, when the switch is up one terminal is connected to the coupling network. When the switch is down that terminal is connected to functional earth. + +a = RJ45 screen cable connection for STPE connections + +b = EUT protective or functional earth connection + +c to d = Terminals of all other signal ports + +$R1 = R2 = 10 \Omega$ + +$C1 = 0.5 \mu F, \pm 10 \%, 5 kV$ , equivalent series resistance (ESR) $< 0.5 \Omega$ , inductance $< 1 \mu H$ , different parasitic values are acceptable provided Note 3 conditions are met. + +NOTE 1 – This test is conducted on each terminal pair selected by having that pair switch up and the remaining switches down. Surging is done with alternating polarities. + +NOTE 2 – This circuit shorts out an injector device or power sourcing equipment power supply. IEEE 802.3 compliant power supplies will not be damaged by this condition. + +NOTE 3 – The initial rate of rise of the short circuit current, $di/dt$ , at 2.5 kV generator charging voltage shall be $60 A/\mu s \pm 10 A/\mu s$ in the first $0.5 \mu s$ . + +**Figure A.6.7-5 – Twisted pair transverse/differential surge test circuit for ports having one or more twisted pair connections such as Ethernet ports, including PoE variants** + +![Figure A.6.7-6: Screen/shield connection high current test for an Ethernet screened/shielded cable port. The diagram shows a 1.2/50-8/20 combination wave generator connected to a resistor R, which is connected to the screen pin or screen of an EUT. The generator return is connected to the EUT reference bar at point 'a'. The EUT reference bar is connected to the EUT at point 'b' via a ground connection E. The EUT has pins labeled 1a, 1b, 2a, 2b, na, and nb. The diagram is labeled K.44(19)_FA.6.7-6.](ec96d99a16edb981eb7defe41a79b57f_img.jpg) + +Figure A.6.7-6: Screen/shield connection high current test for an Ethernet screened/shielded cable port. The diagram shows a 1.2/50-8/20 combination wave generator connected to a resistor R, which is connected to the screen pin or screen of an EUT. The generator return is connected to the EUT reference bar at point 'a'. The EUT reference bar is connected to the EUT at point 'b' via a ground connection E. The EUT has pins labeled 1a, 1b, 2a, 2b, na, and nb. The diagram is labeled K.44(19)\_FA.6.7-6. + +**Figure A.6.7-6 – Screen/shield connection high current test for an Ethernet screened/shielded cable port** + +![Figure A.6.7-7: External Ethernet port, including PoE variants, power cross test circuit. The diagram shows an AC source (Figure A.3-6) connected to the Ethernet port pins 1, 2, 3, 6, 4, 5, 7, and 8. The AC source return is connected to the EUT reference bar at point 'a'. The EUT reference bar is connected to the EUT at point 'b' via a ground connection E. The EUT has a Power port connected to an AC source and a PE connection. Other ports are connected to a Termination and decoupling network. The diagram is labeled K.44(18)_FA.6.7-7.](778a90bfa183fbf83bfe2bf1ed8fa827_img.jpg) + +Figure A.6.7-7: External Ethernet port, including PoE variants, power cross test circuit. The diagram shows an AC source (Figure A.3-6) connected to the Ethernet port pins 1, 2, 3, 6, 4, 5, 7, and 8. The AC source return is connected to the EUT reference bar at point 'a'. The EUT reference bar is connected to the EUT at point 'b' via a ground connection E. The EUT has a Power port connected to an AC source and a PE connection. Other ports are connected to a Termination and decoupling network. The diagram is labeled K.44(18)\_FA.6.7-7. + +**Figure A.6.7-7 – External Ethernet port, including PoE variants, power cross test circuit** + +NOTE 1 – This circuit shorts out an injector device or power sourcing equipment power supply. IEEE 802.3 compliant power supplies will not be damaged by this condition. + +NOTE 2 – This test is also applied to any Ethernet port that fails the insulation resistance test in any polarity. + +NOTE 3 – This test is not applied to any Ethernet port that passes the insulation resistance test in both voltage polarities. + +# Bibliography + +- [b-ITU-T K-Sup.17] ITU-T K-series Recommendations – Supplement 17 (2019), *ITU-T K.44 – Test conditions and methods information*. +- [b-ITU-T K-Sup.18] ITU-T K-series Recommendations – Supplement 18 (2019), *ITU-T K.44 – Causes of telecommunication system overvoltage and overcurrent conditions and their expected levels*. +- [b-ITU-T K.20] Recommendation ITU-T K.20 (2019), *Resistibility of telecommunication equipment installed in a telecommunication centre to overvoltages and overcurrents*. +- [b-ITU-T K.21] Recommendation ITU-T K.21 (2019), *Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents*. +- [b-ITU-T K.45] Recommendation ITU-T K.45 (2019), *Resistibility of telecommunication equipment installed in the access and trunk networks to overvoltages and overcurrents*. +- [b-ITU-T K.46] Recommendation ITU-T K.46 (2012), *Protection of telecommunication lines using metallic symmetric conductors against lightning-induced surges*. +- [b-ITU-T K.50] Recommendation ITU-T K.50 (2016), *Safe limits of operating voltages and currents for telecommunication systems powered over the network*. +- [b-ITU-T K.66] Recommendation ITU-T K.66 (2019), *Protection of customer premises from overvoltages*. +- [b-ITU-T K.82] Recommendation ITU-T K.82 (2010), *Characteristics and ratings of solid-state, self-restoring overcurrent protectors for the protection of telecommunications installations*. +- [b-ITU-T K.98] Recommendation ITU-T K.98 (2014), *Overvoltage protection guide for telecommunication equipment installed in customer premises*. +- [b-ITU-T Handbook] ITU-T Handbook (2004), *Mitigation measures for telecommunication installations*, ITU, Geneva. +<> +- [b-IEC 60050-151] IEC 60050-151 (2001), *International Electrotechnical Vocabulary (IEV). Chapter 151: Electrical and magnetic devices*. +<> +- [b-IEC 60194] IEC 60194 (2015), *Printed board design, manufacture and assembly – Terms and definitions*. +- [b-IEC 60950-1] IEC 60950-1 (2013), *Information technology equipment – Safety – Part 1: General requirements*. +<> +- [b-IEC 61000-4-5] IEC 61000-4-5 (2017), *Electromagnetic compatibility (EMC) – Part 4-5: Testing and measurement techniques – Surge immunity test*. +<> +- [b-IEC 61643-21] IEC 61643-21 (2012), *Low voltage surge protective devices – Part 21: Surge protective devices connected to telecommunications and signalling networks – Performance requirements and testing methods*. +<> +- [b-IEC 62305-4] IEC 62305-4 (2010), *Protection against lightning – Part 4: Electrical and electronic systems within structures*. +<> + +- [b-IEC 62368-1] IEC 62368-1 (2018), *Audio/video, information and communication technology equipment – Part 1: Safety requirements.* +- [b-IEEE 802.3] IEEE Std 802.3 (2015), *IEEE Standard for Ethernet* +<> +- [b-GR-1089] Telcordia Technologies GR-1089-CORE (2011), *Electromagnetic Compatibility and Electrical Safety – Generic Criteria for Network Telecommunications Equipment.* +<> + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.51-201606-I_PDF-E/raw.md b/marked/K/T-REC-K.51-201606-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..44abf192ed5103558051715ea7c6c6d8257f7b4b --- /dev/null +++ b/marked/K/T-REC-K.51-201606-I_PDF-E/raw.md @@ -0,0 +1,519 @@ + + +International Telecommunication Union + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.51** + +(06/2016) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Safety criteria for telecommunication equipment** + +Recommendation ITU-T K.51 + +![ITU logo](6ed175c791b5e156d9c98a8dbcc3318c_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a red lightning bolt striking it, symbolizing telecommunications. To the right of the globe, the text "International Telecommunication Union" is written in a blue, sans-serif font. + +ITU logo + + + +# Recommendation ITU-T K.51 + +## Safety criteria for telecommunication equipment + +## Summary + +Recommendation ITU-T K.51 provides guidance on safety criteria for telecommunication network infrastructure equipment. It specifies requirements intended to reduce risks of fire, electric shock or injury for specified classes of persons who may come into contact with the equipment. This Recommendation refers to the IEC safety standards IEC 60950-1 and IEC 62368-1 and provides additional requirements when these are not covered by the IEC standards. Equipment complying with the relevant requirements in this Recommendation is considered suitable for use in a telecommunication network. However, this Recommendation does not include requirements for performance or functional characteristics of equipment. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.51 | 2000-02-25 | 5 | 11.1002/1000/4914 | +| 2.0 | ITU-T K.51 | 2009-07-14 | 5 | 11.1002/1000/10016 | +| 3.0 | ITU-T K.51 | 2016-06-29 | 5 | 11.1002/1000/12872 | + +## Keywords + +Remote power feeding, safety, telecommunication equipment. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2016 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-----------------------------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 1.1 Equipment covered by this Recommendation ..... | 1 | +| 1.2 Additional requirements ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 2 | +| 3.1 Terms defined elsewhere ..... | 2 | +| 3.2 Terms defined in this Recommendation..... | 4 | +| 4 Abbreviations and acronyms ..... | 6 | +| 5 Safety criteria for telecommunication network infrastructure equipment..... | 6 | +| 5.1 General requirements..... | 6 | +| 5.2 Special requirements ..... | 6 | +| Appendix I – Cross-reference between Recommendation ITU-T K.51, IEC 60950-1 and
IEC 62368-1..... | 10 | +| Bibliography..... | 12 | + +# **Introduction** + +This Recommendation provides guidance on safety criteria for telecommunication network infrastructure equipment. The requirements of the original 2009 version of this Recommendation were developed in cooperation with IEC TC108 based on [IEC 60950-1]. This updated version of this Recommendation incorporates the new definitions and requirements of [IEC 62368-1], a new hazard-based safety standard created by IEC TC 108. This Recommendation should be read together with [IEC 60950-1] and [IEC 62368-1] for best comprehension. + +# Recommendation ITU-T K.51 + +## Safety criteria for telecommunication equipment + +# 1 Scope + +## 1.1 Equipment covered by this Recommendation + +This Recommendation is applicable to mains-powered, battery-powered or remotely-powered telecommunication network infrastructure equipment. + +This Recommendation specifies requirements intended to reduce risks of fire, electric shock, mechanical hazards or injury for the designated classes of user, ordinary person, instructed person, service person and skilled person. + +This Recommendation is intended to reduce such risks with respect to installed equipment, whether it consists of a system of interconnected units or independent units, subject to installing, operating and maintaining the equipment in the manner prescribed by the manufacturer. + +Equipment complying with the relevant requirements in this Recommendation is considered suitable for use in a telecommunication network. However, this Recommendation does not include requirements for performance or functional characteristics of equipment. + +## 1.2 Additional requirements + +Requirements additional to those specified in this Recommendation may be necessary for: + +- equipment intended for operation in special environments, for example: extremes of temperature; excessive dust, moisture or vibration; flammable gases; and corrosive or explosive atmospheres; +- equipment intended to be used in vehicles, on board ships or aircraft, in tropical countries, or at altitudes greater than 2000 m; +- equipment intended for use where ingress of water is possible. + +NOTE – Attention is drawn to the fact that authorities of some countries impose additional requirements. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T K.50] Recommendation ITU-T K.50 (2000), *Safe limits of operating voltages and currents for telecommunication systems powered over the network*. + +[IEC 60950-1] IEC 60950-1 (2005), *Information technology equipment – Safety – Part 1: General requirements*. + +[IEC 60950-21] IEC 60950-21 (2002), *Information technology equipment – Safety – Part 21: Remote power feeding*. + +[IEC 62368-1] IEC 62368-1 (2014), *Audio/video, information and communication technology equipment – Part 1: Safety requirements*. + +NOTE 1 – This Recommendation refers to [IEC 60950-1], but the related concepts or requirements of [IEC 60950] are still applicable in countries where [IEC 60950] is still used. + +NOTE 2 – [IEC 60950-21] is a companion standard to [IEC 60950-1] that covers remote power feeding. IEC TC 108 is developing a corresponding companion standard to [IEC 62368-1] with a designation of IEC 62368-3. + +# 3 Definitions + +In this Recommendation, definitions introduced by [ITU-T K.50], [IEC 60950-1], [IEC 62368-1] and [IEC 60950-21] are used to maintain conformity. For convenience, they are reproduced here. Other definitions, currently under study in IEC, have been added. + +NOTE – The definition of circuits in [IEC 60950-1] is limited to circuits internal to equipment. In [IEC 62368-1] the definition of circuits is limited to circuits external to equipment, which are normally considered to be a telecommunication network. For this Recommendation, the definition of circuits is extended to include network cable conductors that carry the same voltages/currents. + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 basic insulation** [IEC 60950-1]: Insulation to provide basic protection against electric shock. + +NOTE – [IEC 62368-1] refers to "basic safeguard" rather than "basic protection" and notes "This concept does not apply to insulation used exclusively for functional purposes". + +**3.1.2 double insulation** [IEC 60950-1] [IEC 62368-1]: Insulation comprising both basic insulation and supplementary insulation. + +**3.1.3 ELV circuit** [IEC 60950-1]: Secondary circuit with voltages between any two conductors of the circuit, and between any one such conductor and earth (see clause 1.4.9), not exceeding 42,4 V peak, or 60 V d.c., under normal operating conditions, which is separated from hazardous voltage by basic insulation, and which neither meets all of the requirements for an SELV circuit nor meets all of the requirements for a limited current circuit. + +**3.1.4 external circuit** [IEC 62368-1]: Electrical circuit that is external to the equipment and is not mains. + +NOTE – An external circuit is classified as operating at ES1, ES2 or ES3, and PS1, PS2, or PS3 levels. + +**3.1.5 functional insulation** [IEC 62368-1]: Insulation between conductive parts which is necessary only for the proper functioning of the equipment. + +NOTE – [IEC 60950-1] adds the informative note "functional insulation by definition does not protect against electric shock. It may, however, reduce the likelihood of ignition and fire". + +**3.1.6 hazardous voltage** [IEC 60950-1]: Voltage exceeding 42,4 V peak, or 60 V d.c., existing in a circuit that does not meet the requirements for either a limited current circuit or a TNV circuit. + +NOTE – The corresponding [IEC 62368-1] requirement would be voltages exceeding ES1. + +**3.1.7 instructed person** [IEC 62368-1]: Person instructed or supervised by a skilled person as to energy sources and who can responsibly use equipment safeguards and precautionary safeguards with respect to those energy sources. + +NOTE 1 – Supervised, as used in the definition, means having the direction and oversight of the performance of others. + +NOTE 2 – In the context of this Recommendation, the term instructed person is synonymous with user [IEC 60950-1]. + +**3.1.8 limited current circuit** [IEC 60950-1]: Circuit that is so designed and protected that, under both normal operating conditions and single fault conditions, the current that can be drawn is not hazardous. + +NOTE 1 – Simulated faults and abnormal conditions are defined in [IEC 60950-1] clause 1.4.14. + +NOTE 2 – The limit value of d.c. is defined as 2 mA d.c. through a 2 k $\Omega$ resistor connected between any two parts of a limited current circuit, or between any such part and earth in clause 2.4 of [IEC 60950-1]. + +**3.1.9 ordinary person** [IEC 62368-1]: Person who is neither a skilled person nor an instructed person. + +NOTE – In the context of this Recommendation, the term ordinary person is synonymous with user [IEC 60950-1]. + +**3.1.10 primary circuit** [IEC 60950-1]: Circuit that is directly connected to the AC mains supply. + +**3.1.11 prospective touch voltage** [IEC 62368-1]: Voltage between simultaneously accessible conductive parts when those conductive parts are not being touched. + +**3.1.12 public network interface** [b-ISO/IEC 11801]: A point of demarcation between public and private network. In many cases the public network interface is the point of connection between the network provider's facilities and the customer premises cabling. + +**3.1.13 reinforced insulation** [IEC 62368-1]: Single insulation system that provides a degree of protection against electric shock equivalent to double insulation. + +NOTE – [IEC 60950-1] adds the informative note "The term "insulation system" does not imply that the insulation has to be in one homogeneous piece. It may comprise several layers that cannot be tested as basic insulation and supplementary insulation". + +**3.1.14 RFT-C circuit** [ITU-T K.50]: A current limited RFT circuit. + +NOTE – The detailed characteristics of an RFT-C circuit are described in [ITU-T K.50]. + +**3.1.15 RFT-V circuit**: A voltage limited RFT circuit. + +NOTE – The detailed characteristics of an RFT-V circuit are described in [ITU-T K.50]. + +**3.1.16 secondary circuit** [IEC 60950-1]: Circuit that has no direct connection to a primary circuit and derives its power from a transformer, converter or equivalent isolation device, or from a battery. + +NOTE 1 – In the context of this Recommendation, the definition of circuits is extended to include network cable conductors that carry the same voltages/currents. + +NOTE 2 – [IEC 62368-1] does not define the term secondary circuit, but refers to it as "circuit within the equipment not connected to an a.c. mains". + +**3.1.17 SELV circuit** [IEC 60950-1]: Secondary circuit which is so designed and protected that, under normal and single fault conditions, its voltages do not exceed a safe value. + +NOTE 1 – Simulated faults and abnormal conditions are defined in IEC 60950, clause 1.4.14. + +NOTE 2 – Maximum safe d.c. voltages are defined as 60 V d.c., under normal operating conditions and 120 V d.c. for less than 200 ms, under single fault conditions in IEC 60950, clause 2.2. + +**3.1.18 service personnel** [IEC 60950-1]: Persons having appropriate technical training and experience necessary to be aware of hazards to which they are exposed in performing a task and of measures to minimize the danger to themselves or other persons. + +NOTE – In the context of this Recommendation, service personnel must be authorized by the network operator. + +**3.1.19 skilled person** [IEC 62368-1]: Person with relevant education or experience to enable him or her to identify hazards and to take appropriate actions to reduce the risks of injury to themselves and others. + +NOTE – In the context of this Recommendation, the term skilled personnel is synonymous with service personnel [IEC 60950-1]. + +**3.1.20 supplementary insulation** [IEC 60950-1]: Independent insulation applied in addition to basic insulation in order to reduce the risk of electric shock in the event of a failure of the basic insulation. + +NOTE – [IEC 62368-1] refers to "supplementary safeguard" rather than "in addition to basic insulation". + +**3.1.21 TNV circuit** [IEC 60950-1]: Circuit that is in the equipment and to which the accessible area of contact is limited and that is so designed and protected that, under normal operating conditions and single fault conditions, the voltages do not exceed specified limit values. + +NOTE 1 – Simulated faults and abnormal conditions are defined in [IEC 60950-1] clause 1.4.14. + +NOTE 2 – TNV circuits are classified as TNV-1, TNV-2 and TNV-3 circuits. + +**3.1.22 TNV-1 circuit** [IEC 60950-1]: TNV circuit whose normal operating voltages do not exceed the limits for an SELV circuit under normal operating conditions and on which overvoltages from telecommunication networks are possible. + +**3.1.23 TNV-2 circuit** [IEC 60950-1]: TNV circuit whose normal operating voltages exceed the limits for an SELV circuit under normal operating conditions which is not subject to overvoltages from telecommunication networks. + +NOTE – TNV-2 circuits operate a d.c. voltage levels above 60 V d.c. but not exceeding 120 V d.c. + +**3.1.24 TNV-3 circuit** [IEC 60950-1]: TNV circuit whose normal operating voltages exceed the limits for an SELV circuit under normal operating conditions on which overvoltages from telecommunication networks are possible. + +NOTE – TNV-3 circuits operate a d.c. voltage levels above 60 V d.c. but not exceeding 120 V d.c. + +**3.1.25 touch current** [IEC 62368-1]: Electric current through a human body when body parts touch two or more accessible parts or one accessible part and earth. + +NOTE – [IEC 60950-1] has a similar, but less comprehensive, definition for the term touch current. + +**3.1.26 user** [IEC 60950-1]: Any person other than service personnel. + +NOTE – [IEC 60950-1] states that the terms user and operator are synonymous. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 electrical energy source (ES)**: Capacitive source with defined capacitance and charge voltage or prospective touch voltage and the touch current source with defined values for normal operation, abnormal operation, and single fault conditions or a pulsed source with defined values of voltage, current and pulse duration. + +NOTE – [IEC 62368-1] does not have a formal term and definition entry for ES. This definition is a summary of [IEC 62368-1] clause 5.2. + +**3.2.2 electrical energy source class 1, ES1**: Class 1 energy source with levels not exceeding ES1 limits under normal operating conditions, abnormal operating conditions, single fault conditions of a component, device or insulation not serving as a safeguard and not exceeding ES2 limits under single fault conditions of a basic safeguard. + +NOTE 1 – [IEC 62368-1] does not have a formal term and definition entry for ES1. This definition is a summary of [IEC 62368-1] clause 5.2. + +NOTE 2 – ES1 may be accessible to an ordinary person, user, instructed person, service person or a skilled person. ES1 effects are; not painful on the body, but may be detectable and ignition of combustible materials not likely. + +NOTE 3 – ES1 parameter values are given in [IEC 62368-1] clause 5.2. + +**3.2.3 electrical energy source class 2, ES2:** Class 2 energy source with levels not exceeding ES2 limits under normal operating conditions, abnormal operating conditions, and single fault conditions, but exceeding ES1 limits. + +NOTE 1 – [IEC 62368-1] does not have a formal term and definition entry for ES2. This definition is a summary of [IEC 62368-1] clause 5.2. + +NOTE 2 – ES2 may be accessible to an instructed person, service person or a skilled person. ES2 effects are; painful on the body, but not an injury Ignition of combustible materials possible, but limited growth and spread of fire. + +NOTE 3 – ES2 parameter values are given in [IEC 62368-1] clause 5.2. + +**3.2.4 electrical energy source class 3, ES3:** Class 3 energy source with one or more parameters exceeding ES2 limits. + +NOTE 1 – [IEC 62368-1] does not have a formal term and definition entry for ES3. This definition is a summary of [IEC 62368-1] clause 5.2. + +NOTE 2 – ES3 may be accessible to a service person or a skilled person. ES3 effects are; injury to the body and ignition of combustible materials likely with rapid growth and spread of fire. + +NOTE 3 – ES3 parameter values are given in [IEC 62368-1] clause 5.2. + +**3.2.5 electrical power source (PS):** Power source classed by the maximum delivered power values for a power source operating with a worse-case load and for a power source fault operating with the specified normal load. + +NOTE – [IEC 62368-1] does not have a formal term and definition entry for PS. This definition is a summary of [IEC 62368-1] clause 6.2. + +**3.2.6 electrical power source class 1 (PS1):** Circuit where the power source does not exceed a defined limit values measured at specific times. + +NOTE 1 – [IEC 62368-1] does not have a formal term and definition entry for PS1. This definition is a summary of [IEC 62368-1] clause 6.2. + +NOTE 2 – The power available from external circuits described in [IEC 62368-1] Table 14, ID numbers 1 and 2, are considered to be PS1. + +NOTE 3 – [IEC 62368-1] clause 6.2 defined limit values are 500 W <3 s and 15 W >3 s. + +**3.2.7 electrical power source class 2 (PS2):** Circuit where the power source exceeds PS1 limits; and does not exceed a defined limit value measured after a specified time. + +NOTE 1 – [IEC 62368-1] does not have a formal term and definition entry for PS2. This definition is a summary of [IEC 62368-1] clause 6.2. + +NOTE 2 – [IEC 62368-1] clause 6.2 defined limit values are 100 W >5 s. + +**3.2.8 electrical power source class 3 (PS3):** Circuit whose power source exceeds PS2 limits, or any circuit whose power source has not been classified. + +NOTE – [IEC 62368-1] does not have a formal term and definition entry for PS3. This definition is a summary of [IEC 62368-1] clause 6.2. + +**3.2.9 hazardous voltage secondary circuit:** Secondary circuit operating at a voltage exceeding 42,4 V peak, or 60 V d.c., existing in a circuit that does not meet the requirements for either a limited current circuit or a TNV circuit. + +NOTE 1 – Definition is derived from [IEC 60950-1] terms secondary circuit and hazardous voltage. + +NOTE 2 – The term combination hazardous voltage secondary circuit is used in [IEC 60950-1] but not defined. + +**3.2.10 RFT circuit (remote feeding telecommunication circuit):** Equipment circuit, without a direct mains connection or being a SELV circuit or a TNV service or a limited current circuit or an ES1 PS1 circuit, intended to supply or receive d.c. power, at voltages, currents and powers that do + +not exceed defined values under specified operational conditions when connected to paired-conductor communications network on which overvoltages are possible. + +NOTE 1 – A telecommunications service is not required to be present on an RFT circuit. + +NOTE 2 – Specified conditions include normal operating and single fault conditions and may include abnormal operating and safeguard failure conditions. + +NOTE 3 – In the context of this Recommendation, RFT circuits can be regarded as hazardous voltage secondary circuits with defined voltages and currents. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|----------------------------------------------------------| +| ES | Electrical energy Source | +| ES1 | Electrical energy Source class 1 | +| ES2 | Electrical energy Source class 2 | +| ES3 | Electrical energy Source class 3 | +| PS | Power Source | +| PS1 | Power Source class 1 | +| PS2 | Power Source class 2 | +| PS3 | Power Source class 3 | +| RFT | Remote Feeding Telecommunication circuit | +| RFT-C | Remote Feeding Telecommunication circuit-Current limited | +| RFT-V | Remote Feeding Telecommunication circuit-Voltage limited | +| SELV | Safety Extra Low Voltage | +| TNV | Telecommunication Network Voltage | + +# **5 Safety criteria for telecommunication network infrastructure equipment** + +## **5.1 General requirements** + +Telecommunication network infrastructure equipment shall comply with all the relevant requirements of [IEC 60950-1] and [IEC 60950-21] or [IEC 62368-1]. + +## **5.2 Special requirements** + +Remote feeding telecommunication circuits (RFTs circuits) are defined in both [ITU-T K.50] and [IEC 60950-21]. For RFT circuits the requirements in clauses 5.2.1, 5.2.2, 5.2.3 and 5.2.6 apply. + +The requirements for openings in telecommunication network infrastructure equipment are described in [IEC 60950-1] and [IEC 62368-1]; however, the existing requirements do not restrict the entry of vermin or geckos. For enclosure openings, the requirements of clauses 5.2.5 and 5.2.6 apply. + +For the reader's convenience, a cross-reference, between the requirements of this Recommendation and similar paragraphs of [IEC 60950-1] and [IEC 62368-1] is provided in Appendix I. + +### **5.2.1 Protection from electric shock and energy hazards** + +#### **5.2.1.1 Access to energized parts** + +The equipment shall be so constructed that in user or ordinary person access areas, there is adequate protection against contact with bare parts of RFT circuits. An instructed person may have access to electrical energy source class 2 (ES2) areas. + +#### **5.2.1.2 Protection in service access areas** + +Bare parts at hazardous voltages, except for RFT circuits, shall be located or guarded so that unintentional contact with such parts is unlikely during service operations involving other parts of the equipment. + +Bare parts at hazardous (ES2 or electrical energy source class 3 (ES3)) voltage, including RFT circuits, shall be located or guarded so that accidental shorting to safety extra low voltage (SELV) circuits or to telecommunication network voltage (TNV) circuits or electrical energy source class 1 (ES1) circuits or non-RFT ES2 circuits, for example by tools or test probes used by service personnel, is unlikely. + +#### **5.2.1.3 Protection in restricted access locations** + +For equipment to be installed in a restricted access location, contact is permitted with the bare parts of RFT circuits by the test finger as defined in Figure 2A of [IEC 60950-1] or Figure V1 and V2 of [IEC 62368-1]. However, such parts shall be so located or guarded that unintentional contact is unlikely. + +### **5.2.2 Interconnection of equipment** + +#### **5.2.2.1 General requirements** + +Where equipment is intended to be electrically connected to other equipment, interconnection circuits shall be selected to provide continued conformance to the requirements of [ITU-T K.50] for RFT circuits, after making the connections. + +NOTE 1 – This is normally achieved by connecting RFT-C circuits to RFT-C circuits and RFT-V circuits to RFT-V circuits. + +NOTE 2 – It is permitted for an interconnecting cable to contain more than one type of circuit (e.g., SELV, limited current, TNV, ELV, RFT, or hazardous voltage) provided that they are separated as required by this Recommendation, [IEC 60950-1] and [IEC 62368-1]. + +#### **5.2.2.2 Types of interconnecting circuits** + +An RFT can be an interconnection circuit. + +#### **5.2.2.3 Interconnection between RFT circuits** + +The interconnection of one RFT-V circuit to another RFT-V circuit shall not result in exceeding the limits specified in [ITU-T K.50]. The interconnection of one RFT-C circuit to another RFT-C circuit shall not result in exceeding the limits specified in [ITU-T K.50]. + +### **5.2.3 Protection of telecommunication network service personnel, and users of other equipment connected to the network, from hazards in the equipment** + +#### **5.2.3.1 Protection from hazardous voltages** + +Circuitry intended to be directly connected to a telecommunication network shall comply with the requirements of an SELV circuit, a TNV circuit, ES1 circuit, ES2 circuit or an RFT circuit. + +### **5.2.4 Separation from other circuits and parts** + +An RFT circuit shall be separated from: + +- other RFT circuits by functional isolation; provided that neither circuit exceeds the limits of [ITU-T K.50] if this isolation is short-circuited. Otherwise, the circuits shall be separated as if one were at a hazardous voltage; +- ELV circuits by supplementary insulation; +- earthed accessible parts, earthed SELV circuits, earthed TNV circuits, earthed ES1 circuits and earthed ES2 circuits by basic insulation; +- unearthed accessible parts, unearthed SELV circuits, unearthed TNV circuits, unearthed ES1 circuits, and circuits at hazardous (ES2 or ES3) voltages by one or both of the following: + - double or reinforced insulation; + - basic insulation, together with protective screening connected to the main protective earthing terminal. + +Compliance is checked by inspection and measurement. + +### 5.2.5 Preventing vermin ingress + +Vermin ingress can have a number of adverse effects such as: + +- biting or stinging of service personnel; +- causing faults in the equipment; +- causing a fire in the equipment. + +Equipment enclosure holes or openings are restricted in size, by [IEC 60950-1], to prevent hazardous contact with energized circuitry. This is verified by the use of a jointed test finger, pin and probe such as described in [IEC 60950-1], Figures 2A, 2B and 2C, respectively or [IEC 62368-1] Figures V1, V2, V3 and V4, respectively. + +The test pin has the smallest diameter. An enclosure opening smaller than 3 mm will prevent test pin entry. Circular or mesh openings of 3 mm or less will also prevent the entry of most common stinging insects such as: honey bees, bumble bees, yellow jackets, bald-faced hornets, European hornets, and some other solitary wasp species. Only very small insects, such as 1 mm long fire ants, can still enter through a 3 mm hole and establish nests. + +Ground level and subterranean enclosures are particularly vulnerable to ant infestation. Mounting the enclosure above ground, on a pole or to the side of a building reduces the risk of infestation. Enclosures designed to prevent the entry of rain and dust further reduce the risk of ant infestation. + +### 5.2.6 Installation instructions + +For equipment using an RFT circuit intended for interconnection with other equipment, the installation instructions shall specify all of the following: + +- the effective capacitance of the equipment: + - between the connection points for the conductors of the telecommunication network; and + - between the connection point for one conductor of the telecommunication network and earth; +- that a system assessment shall be carried out to ensure that the effective capacitance of the total system, including the capacitance of the equipment, does not exceed the values specified in Figure 1; +- that the voltage rating of the telecommunication network must be adequate for the normal RFT circuit voltage, together with any superimposed transient; +- RFT circuit voltage. + +For equipment with enclosure holes or openings, the installation instructions shall specify detailed installation requirements for preventing vermin or gecko entry, e.g., installation location, safeguard methods. + +![Log-log graph showing capacitance limits (C μF) vs voltage (U V) for RFT circuits. Two curves are plotted: a dashed line for 'Line to line, hand to hand contact' and a solid line for 'Line to earth, hand to foot contact'. The graph shows a downward trend for both as voltage increases from 120V to 1500V.](eaae122ace5c0d761133c6ce971a6ffd_img.jpg) + +| Voltage (U V) | Line to line, hand to hand contact (C μF) | Line to earth, hand to foot contact (C μF) | +|---------------|-------------------------------------------|--------------------------------------------| +| 120 | ~2000 | ~12 | +| 200 | ~300 | ~4 | +| 350 | ~70 | ~1.5 | +| 400 | ~6 | ~1.2 | +| 1000 | ~1.2 | ~0.3 | +| 1500 | ~0.8 | ~0.15 | + +Log-log graph showing capacitance limits (C μF) vs voltage (U V) for RFT circuits. Two curves are plotted: a dashed line for 'Line to line, hand to hand contact' and a solid line for 'Line to earth, hand to foot contact'. The graph shows a downward trend for both as voltage increases from 120V to 1500V. + +**Figure 1 – Limits for capacitance values of RFT circuits or of the total system** + +# Appendix I + +## Cross-reference between Recommendation ITU-T K.51, IEC 60950-1 and IEC 62368-1 + +(This appendix does not form an integral part of this Recommendation.) + +For the reader's convenience, this appendix provides a cross-reference between the requirements of this Recommendation and paragraphs of [IEC 60950-1] and [IEC 62368-1] where similar requirements for other circuits are given (Table I.1). + +Table I.1 + +| ITU-T K.51 clause | IEC 60950-1 paragraph | IEC 62368-1 paragraph | +|----------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------| +| 5.2.1.1
Access to energized parts | 2.1.1.1
Access to energized parts | 5.3.2
Protection of an ordinary person
(Annex V for probes) | +| 5.2.1.2
Protection in service access areas | 2.1.2
Protection in service access areas | 5.3.3
Protection of an instructed person
(Annex V for probes) | +| 5.2.1.3
Protection in restricted access locations | 2.1.3
Protection in restricted access locations | 5.3.4
Protection of a skilled person
(Annex V for probes) | +| 5.2.2
Interconnection of equipment | 3.5
Interconnection of equipment | 6.7
Safeguards against fire due to the connection of secondary equipment | +| 5.2.2.1
General requirements | 3.5.1
General requirements | Annex Q (normative)
Interconnection with building wiring | +| 5.2.2.2
Types of interconnecting circuits | 3.5.2
Types of interconnection circuits | — | +| 5.2.2.3
Interconnection between RFT circuits | — | — | +| 5.2.3
Protection of telecommunication network service personnel, and users of other equipment connected to the network, from hazards in the equipment | 6.1
Protection of telecommunication network service persons, and users of other equipment connected to the network, from hazards in the equipment | 5.7.6
Prospective touch voltage and touch current due to external circuits | +| 5.2.3.1
Protection from hazardous voltages | 6.1.1
Protection from hazardous voltages | 5.7.6
Prospective touch voltage and touch current due to external circuits | +| 5.2.4
Separation from other circuits and parts | — | | + +**Table I.1** + +| ITU-T K.51 clause | IEC 60950-1 paragraph | IEC 62368-1 paragraph | +|------------------------------------|------------------------------|------------------------------| +| 5.2.5
Preventing vermin ingress | – | | +| 5.2.6
Installation instructions | – | | + +# Bibliography + +[b-ISO/IEC 11801] ISO/IEC 11801:2002, *Information technology – Generic cabling for customer premises*. +<[http://www.iso.org/iso/iso\\_catalogue\\_tc/catalogue\\_detail.htm?csnumber=36491](http://www.iso.org/iso/iso_catalogue_tc/catalogue_detail.htm?csnumber=36491)> + + + +## **SERIES OF ITU-T RECOMMENDATIONS** + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.57-201606-I_PDF-E/raw.md b/marked/K/T-REC-K.57-201606-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..4443cd2c10b4e825b3649e4e1e919700bcbad52d --- /dev/null +++ b/marked/K/T-REC-K.57-201606-I_PDF-E/raw.md @@ -0,0 +1,1911 @@ + + +I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n + +# **ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +# **K.57** + +(06/2016) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +# --- **Protection measures for radio base stations sited on power line towers** + +Recommendation ITU-T K.57 + +![ITU logo](6ed175c791b5e156d9c98a8dbcc3318c_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a blue globe with a red lightning bolt striking it. To the right of the globe, the text "International Telecommunication Union" is written in blue. + +ITU logo + +**International +Telecommunication +Union** + + + +## Recommendation ITU-T K.57 + +# Protection measures for radio base stations sited on power line towers + +## Summary + +Recommendation ITU-T K.57 specifies measures to be taken with respect to safety and risk of damage to equipment through earth potential rise when power line towers are used for locating radio base stations. + +Locating radio base station antennas in power line towers is mainly of interest in rural areas, where there are no tall buildings where antennas may be installed. At the same time, some precautions have to be taken in order to make the installation safe and not to cause damage to the equipment in case of earth fault, earth potential rise and lightning. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|--------------------------------------------------------------------------------------------| +| 1.0 | ITU-T K.57 | 2003-09-06 | 5 | 11.1002/1000/6501 | +| 2.0 | ITU-T K.57 | 2016-06-13 | 5 | 11.1002/1000/12873 | + +## Keywords + +Earth fault, earth potential rise, lightning protection, power line tower, radio base station. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2016 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +# Table of Contents + +| | | Page | +|-------|--------------------------------------------------------------------------------------------------------------------------------------------------|------| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 4 | Abbreviations and acronyms ..... | 2 | +| 5 | Conventions ..... | 2 | +| 6 | General..... | 2 | +| 6.1 | Earth fault characterization of directly earthed power systems..... | 3 | +| 6.2 | Earth fault characterization of non-directly earthed power systems ..... | 3 | +| 6.3 | Earth potential rise (EPR)..... | 3 | +| 7 | Power supply ..... | 4 | +| 7.1 | Feeding from the LV network ..... | 4 | +| 7.2 | Feeding from a MV network ..... | 8 | +| 7.3 | Feeding from the HV line..... | 8 | +| 8 | Requirements on the antenna system..... | 8 | +| 9 | Telecommunication cables ..... | 9 | +| 10 | Earthing arrangements ..... | 9 | +| 11 | Installation and maintenance ..... | 9 | +| 12 | Examples of installations..... | 10 | +| | Appendix I – Guide on the coordination of the isolation level required for power supply circuit and the potential rise of power line towers..... | 12 | +| I.1 | Scope of the investigation ..... | 12 | +| I.2 | Investigated options, parameters ..... | 12 | +| I.3 | Analysis of the results ..... | 15 | +| I.4 | Estimation of the required isolation level..... | 29 | +| | Appendix II – Guide on the LV feeding arrangement ..... | 33 | +| II.1 | LV feeding arrangement..... | 33 | +| II.2 | Protection principles ..... | 34 | +| II.3 | Selection of the design values for the protection..... | 36 | +| II.4 | Options for the feeding of multiple RBSs ..... | 37 | +| | Appendix III – Characterization and control of the EPR zone of tower earthing and estimation of the minimum length of the junction section ..... | 40 | +| III.1 | Characterization of the zone of EPR of the tower earthing..... | 40 | +| III.2 | Control of touch and step voltages by potential PGE..... | 44 | +| III.3 | Estimation of minimum length values..... | 54 | +| | Bibliography..... | 58 | + + + +## Recommendation ITU-T K.57 + +# Protection measures for radio base stations sited on power line towers + +# 1 Scope + +This Recommendation specifies measures to be taken with respect to safety and risk of damage to equipment through earth potential rise when power line towers are used for locating radio base stations. + +Special arrangements for lightning protection at these installations are also covered. + +It considers both the power feeding and the connection to the telecommunication network. + +It also mentions the risk of disturbances to the transmitting antenna. + +Lightning protection of radio base stations is treated in [ITU-T K.56]. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.8] Recommendation ITU-T K.8 (1988), *Separation in the soil between telecommunication cables and earthing system of power facilities.* +- [ITU-T K.52] Recommendation ITU-T K.52 (2014), *Guidance on complying with limits for human exposure to electromagnetic fields.* +- [ITU-T K.56] Recommendation ITU-T K.56 (2010), *Protection of radio base stations against lightning discharges.* +- [ITU-T K.68] Recommendation ITU-T K.68 (2008), *Operator responsibilities in the management of electromagnetic interference by power systems on telecommunication systems.* +- [IEC 61643-11] IEC 61643-11 (2011), *Low-voltage surge protective devices – Part 11: Surge protective devices connected to low-voltage power systems – Requirements and test methods.* +- [IEC 61643-12] IEC 61643-12 (2008), *Low-voltage surge protective devices – Part 12: Surge protective devices connected to low-voltage power distribution systems – Selection and application principles.* + +# 3 Definitions + +This Recommendation defines the following terms: + +**3.1 potential grading earth (PGE):** An electrode system laid at small depth around the equipment cabinet(s) for controlling the step and touch voltages. It is bonded to both the tower and the cabinet(s) earth. + +**3.2 directly earthed power system:** High voltage (HV) and medium voltage (MV) power systems, whose neutral is connected to earth through a low impedance or directly. + +**3.3 non-directly earthed power system:** High voltage (HV) and medium voltage (MV) power systems, whose neutral is connected to earth through a high impedance (resistor or inductor), or arc extinguishing (Petersen) coil or isolated. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations: + +| | | +|-------|----------------------------------| +| EPR | Earth Potential Rise | +| HV | High Voltage | +| LV | Low Voltage | +| MOV | Metal Oxide Varistor | +| MV | Medium Voltage | +| RBS | Radio Base Station | +| SPD | Surge Protective Device | +| T-EPR | Tower-Earthing Potential Rise | +| Z-EPR | Zone of the Earth Potential Rise | + +# **5 Conventions** + +None. + +# **6 General** + +Locating radio base station antennas in power line towers is mainly of interest in rural areas, where there are no tall buildings where antennas may be installed. At the same time, some precautions have to be taken in order to make the installation safe and not to cause damage to the equipment. + +At every power line tower with a radio base antenna, there is a cabinet located near the tower or between the tower legs. This cabinet is sometimes elevated, if possible. The location of the equipment cabinet is not a safety issue, but rather a question of accessibility to the tower. + +This cabinet is hosting equipment for transmitting and receiving and has cable connections for power feeding and signal transmission. + +There is a transformer cabinet for power supply in close proximity to the equipment cabinet or in a dedicated part of the cabinet. + +The antenna may be mounted below or above the phase conductors or even above the overhead earth wire(s), if any. + +The power line may belong to a directly or non-directly earthed power system. + +There are two phenomena that have to be considered: + +- Earth potential rise in case of earth fault at the tower – This problem is treated by isolating that part of the radio base station (RBS) equipment, which has external metallic connection, against its cabinet and equipment, which is bonded to the tower. +- Lightning hitting the tower – This problem is handled by bonding the above-mentioned parts of the RBS equipment through suitable surge protective devices (SPDs) in order not to jeopardize the isolation for earth potential rise (EPR). + +For further information, see clause II.2. + +## 6.1 Earth fault characterization of directly earthed power systems + +When an earth fault occurs in a power system with directly earthed neutral, there will be an earth potential rise at the feeding substations, and also at the fault location, which may be the tower, where the radio base station is installed. In most cases the EPR will be much higher at the fault location because the equivalent impedance to the earth at this point is much higher than at the substations. + +For further information, see Appendix I. + +## 6.2 Earth fault characterization of non-directly earthed power systems + +When an earth fault occurs in a power system with non-directly earthed neutral, the EPR will be very small due to the small amplitude of the fault current. However, double earth faults may also occur. In that case the fault current will be much higher and result in a substantial EPR at both fault locations. + +## 6.3 Earth potential rise (EPR) + +When a single earth fault on a power line of a network with directly earthed neutral or a double earth fault on power line(s) of a network with non-directly earthed neutral occurs, a large EPR will appear at the tower, maybe tens of kVs. The EPR, as a general term, involves two kinds of potential rise as explained in the following. + +### 6.3.1 Tower-earthing potential rise (T-EPR) + +The tower potential rise is the potential of the earthing (footing) of tower with respect to the remote earth occurring during earth fault. + +The amplitude of the tower-earthing potential rise (T-EPR) depends on a number of different factors such as: + +- a) earth fault current amplitude; +- b) earth resistance of the pole; +- c) aerial and underground earth wires, if applied; +- d) distance to the feeding power stations; +- e) span between the towers. + +The factors mentioned in items d) and e) are of secondary importance. + +NOTE 1 – When the power line is equipped with aerial or underground earth wires, the majority of the fault current returns through these wires and only a fraction of the earth fault current flows through the tower footing. The T-EPR can be characterized by the product of that fraction ( $3I_0E$ ) of the zero-sequence component ( $3I_0$ ) of the earth fault current that is passing through the tower footing, and the earthing resistance ( $R$ ) of the tower, i.e., $3I_0ER$ . + +The T-EPR may be calculated or preferably measured in order to determine, whether special arrangements are not needed, which is unusual; see Appendix I. + +NOTE 2 – When the power line is not equipped with earth wires, the whole of the fault current flows through the tower footing. The T-EPR can be calculated by the product of the zero-sequence component ( $3I_0$ ) of the earth fault current, and the earthing resistance ( $R$ ) of the tower, i.e., $3I_0R$ . + +The T-EPR shall be calculated for each given case by considering the actual conditions of the tower holding the base station. + +### 6.3.2 Zone of the earth potential rise (Z-EPR) + +The zone of the earth potential rise (Z-EPR) is that area surrounding the tower of the power line where earth potential with respect to the remote earth occurs in case of single phase to earth fault, or in case of non-directly earthed network, double earth fault. This potential falls more or less rapidly + +in the earth ("potential funnel") as the distance from the tower footing increases. The magnitude and the way of decrease of the potential depends on the following factors: + +- a) the magnitude of the T-EPR causing the Z-EPR; +- b) the geometry (size and structure) of the earthing system; +- c) soil characteristics (geological nature, stratification, etc.). + +More detailed characterization of the Z-EPR is given in Appendix III. + +# 7 Power supply + +The RBS equipment may be powered in the following ways: + +- 1) From the low voltage (LV) (voltage levels not exceeding 1000 V a.c.) network through an isolating transformer in order to separate the EPR area from the surrounding: This is most commonly used. +- 2) From a medium voltage (MV) (voltage levels lying between LV and HV) power network: In this case you can use the MV/LV transformer as isolation between the EPR area and the surrounding. +- 3) From the high voltage (HV) (voltage levels exceeding 100 kV a.c.) power line itself for example through capacitive voltage divider or inductively coupled loop: This method is expensive and hardly used. + +For further information, see Appendix II. + +## 7.1 Feeding from the LV network + +Figure 1 shows the arrangement, when the equipment cabinet is powered from the LV network. + +![Diagram of typical arrangement of LV feeding](1eadbbe42cfcac5c0023577110aec5e3_img.jpg) + +The diagram illustrates the typical arrangement for feeding a feeding cabinet from a low voltage (LV) network. On the left, a 'Public LV network' is shown with a 'Coupling point' where a 'Feeding LV line' is connected. This line runs horizontally across the ground, supported by several poles. At the right end of the line, there is a 'Junction point (box)'. From this box, a 'Junction cable' with a 'typical length range [m]' of $30 \leq l < 60$ connects to a 'Feeding cabinet', which is represented by a yellow rectangle. The feeding cabinet is located at the base of a 'Power line tower'. The ground is indicated by hatching at the bottom of the diagram. The label 'K.57(16)\_F01' is in the bottom right corner. + +Diagram of typical arrangement of LV feeding + +**Figure 1 – Typical arrangement of LV feeding** + +Apart from what is described in the different options below, the following shall be observed: + +- The cable shall not be stapled towards earthed parts in the transformer cabinet. +- The cable shall approach the cabinet perpendicular to the power line in order to avoid induced voltages. +- If the ground does not allow buried cable, aerial cable may be used. +- In order to protect the LV network, other measures have to be fulfilled that may be required by the LV network operator. + +- As an alternative to a LV cable in plastic pipe, a MV cable which has the required insulation level, may be used for power supply. This shall be installed at least 50 m nearest to the tower. The MV cable shall not contain screen, i.e., MV cable manufactured without screen for this purpose is required. + +The applicable protection practice, such as the way of connecting and selecting SPDs, is significantly affected by the feeding arrangement, especially the structure of the junction cable that together with the isolating transformer are commonly protected with the SPDs applied at the feeding cabinet of the RBS. + +### 7.1.1 Options for the junction cable structure + +The junction cable can be classified in two main categories according to the absence or presence of screen. It is preferred to be underground, but it may be overhead. + +#### 7.1.1.1 Junction cable without metallic screen and neutral + +In this case the metallic parts of the cable are only the three phase conductors. The voltage stresses (lightning impulse and 50-Hz potential rise) occur between the phase conductors and the earth. Regarding the ways of providing the appropriate insulation with respect to the earth, the options are the following: + +- a) LV three-core cable with additional increase of isolation to earth: The additional isolation shall be provided by insulating jacket on the cable or placing the junction cable in watertight insulating tube. +- b) MV cable without metallic screen: In this case, the required isolation to earth is provided by essentially the core insulation itself, which is further increased by the plastic sheath (jacket) of the cable. + +NOTE 1 – MV cables with the required voltage level (10 kV or above) are generally manufactured with metallic screened cores. Therefore, the cable without screen may be manufactured by special order. + +NOTE 2 – The required MV cable may be three single-core cables (typical for voltage levels of 20 kV or above). + +#### 7.1.1.2 Junction cable with metallic screen or neutral + +In this case the typical cable is the LV three-conductor cable with concentric copper wire screen around the core bundle. When a four-core screened LV cable is used, the neutral conductor shall be bonded to the screen at the terminals of the junction cable. According to the protection principle, the screen is earthed at the junction point (outside the EPR zone), thus the voltage stresses (lightning impulse and 50-Hz potential rise) occur between the screen and the earth especially in the vicinity of the tower. The required isolation to earth shall be provided by additional insulating jacket on the cable or placing the junction cable in watertight insulating tube. + +NOTE – The screen carries the surge current diverted by the MV SPD; thus, its total cross-sectional area shall be at least 35 mm2. + +### 7.1.2 Options of protection schemes at the feeding cabinet and junction point + +Three options are recommended corresponding to the different feeding arrangements. + +#### 7.1.2.1 Scheme for junction cable without metallic screen and neutral + +The type and ways of connection of SPDs are in case of junction cable without metallic screen and neutral (see Figure 2, Option 1): + +- 1) At the feeding cabinet, MV SPD (e.g., metal oxide varistor (MOV)) is connected between each phase conductor and the tower earthing. +- 2) At the junction point, LV SPD is connected between each phase conductor and the earth. + +![Figure 2: Schematic diagram of a junction cable without screen protected by MV arresters at the feeding cabinet and LV SPD at the junction box. The diagram shows four main components: Junction point (box), Feeding cabinet, Isolating transformer, and Equipment cabinet. The Junction point (box) contains LV arresters connected between the Feeding LV line (L1, L2, L3, N) and earth. The Feeding cabinet contains MV arresters connected between the MV cable and earth. The Isolating transformer is connected between the Feeding cabinet and the Equipment cabinet. The Equipment cabinet contains the Ant. feeding (Equipped with LV protection) connected to the Isolating transformer. Connections to earthing of tower are shown at the bottom. The diagram is labeled K.57(16)_F02.](d4af765160d04ecef538e5066006dc77_img.jpg) + +Figure 2: Schematic diagram of a junction cable without screen protected by MV arresters at the feeding cabinet and LV SPD at the junction box. The diagram shows four main components: Junction point (box), Feeding cabinet, Isolating transformer, and Equipment cabinet. The Junction point (box) contains LV arresters connected between the Feeding LV line (L1, L2, L3, N) and earth. The Feeding cabinet contains MV arresters connected between the MV cable and earth. The Isolating transformer is connected between the Feeding cabinet and the Equipment cabinet. The Equipment cabinet contains the Ant. feeding (Equipped with LV protection) connected to the Isolating transformer. Connections to earthing of tower are shown at the bottom. The diagram is labeled K.57(16)\_F02. + +**Figure 2 – Junction cable without screen protected by MV arresters at the feeding cabinet and LV SPD at the junction box connected between each phase conductor and the earth: Option 1** + +#### 7.1.2.2 Scheme for junction cable with metallic screen or neutral + +In case of junction cable with metallic screen with or without neutral, the type and ways of connection of SPDs are classified in the following two options: + +##### a) *Applying MV SPD arrester only to the screen* + +According to this protection scheme the type and ways of connection of SPDs are as follows (see Figure 3, Option 2): + +- 1) At the feeding cabinet a single MV SPD arrester is connected between the screen and the tower earthing. +- 2) At the junction point the screen is directly earthed and no LV SPD is applied at all. + +NOTE 1 – When applying this protection scheme, it is assumed that the voltages of the phase conductors are, practically, equalized with the voltage of the screen due to the close inductive and capacitive coupling between the screen and the phase conductors. + +##### b) *Applying the combination of MV SPD arrester and LV SPDs* + +According to this protection scheme the type and ways of connection of SPDs are as follows (see Figure 4, Option 3): + +- 1) At the feeding cabinet a single MV SPD arrester is connected between the screen and the tower earthing, and LV SPDs are connected between each phase conductor and the screen. +- 2) At the junction point the screen is directly earthed, and LV type SPD is connected between each phase conductor and the screen. + +NOTE 2 – When applying this protection scheme, the voltage equalizing between the screen and the phase conductors is ensured by the LV SPDs. + +![Figure 3: Junction cable with screen protected by a single MV arrester connected between the screen and the tower earthing at the feeding cabinet and the screen is directly earthed at the junction point: Option 2](af7916c89a458fdab6c3f443217388ae_img.jpg) + +This diagram illustrates the electrical protection scheme for a junction cable. On the left, the 'Feeding LV line' (L1, L2, L3, N) enters a 'Junction point (box)'. Inside the box, the conductors are connected to an 'LV junction cable with screen'. The 'Isolating tube screen' is bonded with the neutral conductor if any and is directly earthed at the junction point. The cable passes through a 'Feeding cabinet' which contains an 'MV arrester' connected between the screen and the 'Connections to earthing of tower'. The cable then connects to an 'Isolating transformer', which outputs L1, L2, L3, N, and PE. Finally, the power is delivered to an 'Equipment cabinet' labeled 'Ant. feeding (Equipped with LV protection)'. The diagram is labeled K.57(16)\_F03. + +Figure 3: Junction cable with screen protected by a single MV arrester connected between the screen and the tower earthing at the feeding cabinet and the screen is directly earthed at the junction point: Option 2 + +**Figure 3 – Junction cable with screen protected by a single MV arrester connected between the screen and the tower earthing at the feeding cabinet and the screen is directly earthed at the junction point: Option 2** + +![Figure 4: Junction cable with screen protected by a single MV arrester connected between the screen and the tower earthing at the feeding cabinet and the screen is directly earthed at the junction point; in addition LV arresters are connected between each phase conductor and the screen at both the feeding cabinet and the junction box: Option 3](eefe19c5e14dc4d6c316b7f7fbb7d7d7_img.jpg) + +This diagram shows an enhanced protection scheme. It follows the same basic layout as Figure 3 but adds 'LV arresters' at two locations: first, at the 'Junction point (box)' between each phase conductor (L1, L2, L3) and the screen; second, inside the 'Feeding cabinet' between each phase conductor and the screen. The 'MV arrester' and 'Isolating transformer' components remain the same. The diagram is labeled K.57(16)\_F04. + +Figure 4: Junction cable with screen protected by a single MV arrester connected between the screen and the tower earthing at the feeding cabinet and the screen is directly earthed at the junction point; in addition LV arresters are connected between each phase conductor and the screen at both the feeding cabinet and the junction box: Option 3 + +**Figure 4 – Junction cable with screen protected by a single MV arrester connected between the screen and the tower earthing at the feeding cabinet and the screen is directly earthed at the junction point; in addition LV arresters are connected between each phase conductor and the screen at both the feeding cabinet and the junction box: Option 3** + +### 7.1.3 Protection of the feeding line including the coupling point + +The connecting line, between the junction and coupling points including the coupling point itself, should be protected according to the requirements of low-voltage power distribution systems such as given in [IEC 61643-11] and [IEC 61643-12]. The protection scheme, especially the bonding and earthing conditions, shall also comply with the requirements for subscriber premises given in [ITU-T K.31]. + +### 7.1.4 Protection of MV/LV transformer located in the zone of EPR + +In case of RBS fed from MV/LV transformer located in the zone of EPR, the following means of protection shall be applied: + +- a) Equalizing through a copper wire of at least 35 mm2 between the HV tower earthing and the earthing bar at the transformer; +- b) MV SPD (e.g., MOV or similar) arrester connected between each phase conductor on the MV side and the earthing bar at the transformer; + +NOTE 1 – This is normally applied to protect the transformer against lightning surges coming from the MV line. + +- c) LV-type SPD is connected between each phase conductor and the tower earth in the feeding cabinet of the RBS. + +NOTE 2 – This LV-type SPD is applied for the protection of the equipment of the radio base station. + +### **7.1.5 Protection when feeding from MV/LV transformer located outside the EPR zone and only serving the RBS** + +In case of RBS fed from MV/LV transformer located out of the EPR zone, but not very far (less than 50-60 m), the applicable protection scheme is the following: + +- a) The LV/LV isolating transformer shall be installed in the feeding cabinet. +- b) The LV feeding line is considered as junction section; therefore it shall be protected according to point 7.1.2 using that option, which corresponds to the actual installation. + +NOTE 1 – The protection scheme given in clause 7.1.2.2 a) is not recommended especially when the power metering facilities are installed at the location of the MV/LV transformer. + +- c) MV SPD shall be connected between each phase of the MV side and the earthing at the MV/LV transformer. + +NOTE 2 – This is normally applied to protect the transformer against lightning surges coming from the MV line. The MV SPD may not be necessary when the transformer is fed by well-shielded MV cable. + +## **7.2 Feeding from a MV network** + +As an alternative the equipment cabinet may be powered from a distribution network, typically 10 to 20 kV. In this case you get a higher insulation level on cables and transformer automatically. The isolating transformer is then substituted with a distribution transformer; see Figure 5. However, the screen of the MV cable should be isolated and protected by MV-type SPD against the tower earthing according to clause 7.1.2.2 and Figure 3. The required screen-to-earth isolation shall be provided by additional insulating jacket on the MV cable or placing the cable in watertight insulating tube along the junction section (see Table III.2). + +## **7.3 Feeding from the HV line** + +No method is known at present that is justified technically and economically. This method of feeding the RBS is therefore not recommended. + +# **8 Requirements on the antenna system** + +Following are the requirements on the installation of the RBS: + +- Coaxial cables between equipment cabinet and antenna(s) shall be placed in a suitable way in dedicated cable ducts or clamped to the tower structure, in order that maintenance and fault repair of the equipment and the towers are not complicated. +- Underground cables between equipment cabinet and tower shall be laid in isolated pipes. +- Communication equipment, antenna and accessories shall be type-approved according to national regulations and requirements. + +- The antennas will be placed in strong electric fields, where they may be exposed to corona and sparks. The owner of the antennas must be aware of this in order to avoid degraded function of the antennas. +- Depending on the type of tower and the location of the antenna(s), the levels of electric and magnetic field strengths from the power line may be achieved from the power company. +- If antennas are placed above the overhead earth wires, they shall be provided with lightning protection; see [ITU-T K.56]. + +# 9 Telecommunication cables + +In order to avoid problems of induction and EPR at earth faults, the telecommunication should use metal-free fibre optic cables or radio links; see Figures 6 and 7. + +If metallic cables are used for the telecommunication, they shall be constructed and connected under the same conditions as the LV power supply. It means that they shall: + +- have an adequate isolation level; +- be laid in an insulating, water-tight, plastic tube; +- be terminated via a transformer; +- be provided with feasible over-voltage arrestors. + +The transition point should not be closer than the point, where the EPR is expected to be 650 V. This voltage level is the limit for short-term overvoltage with a duration of $\leq 0.5$ s. Other levels may be chosen with reference to [ITU-T K.68]. + +See also [ITU-T K.8]. + +# 10 Earthing arrangements + +The earthing arrangements are important for the safety and protection of the equipment. The following shall be applied: + +- Metallic parts of the antenna shall be bonded to the coaxial screen and earthed to the metallic structure of the tower. +- The other end of the screen shall be connected to the earth of the equipment cabinet. +- PGE system shall be laid about 0.3 m deep around the equipment cabinet for the control of the touch and step voltages. This can be implemented as either single or double frame system corresponding to the actual potential level to be controlled. The grading electrodes shall be bonded both to the cabinet earth and to the legs of the tower at least at two corners (see Figure III.14). The bonding shall be applied diagonally, when the cabinet is located between the legs (see thick line bonds in Figure III.15). Guidance is given for the proposed locations of the grading frames in Appendix III (see clause III.2.2 b) and Figures III.14 and III.15). +- The earthing system of the equipment and transformer cabinets shall be bonded to the earthing of the tower through a copper wire of at least 35 mm2. Note that this may require cathodic protection when different metals are used in the earthing network. + +# 11 Installation and maintenance + +Installation and maintenance of the equipment located in the tower such as antennas and cables, are restricted to people specially trained with knowledge about electric and magnetic fields from power lines, normally linesmen of the power company. However, special caution has to be observed concerning the risk of exposure to electromagnetic fields from the RBS antenna(s). For guidance, see [ITU-T K.52]. + +The installations on ground are normally done by specially instructed RBS people. National regulations may require further restrictions on this type of work. + +# 12 Examples of installations + +Figures 5 to 7 give examples of installations. + +Figure 8 shows an installation where unauthorized access is prevented. + +![Diagram of MV power feeding of RBS](16152cf1d84aea10848758f51a91ff6a_img.jpg) + +This diagram illustrates the electrical installation for an MV power feeding of an RBS. On the left, a lattice tower represents the RBS, with a yellow lightning rod at its top. A grey box labeled 'RBS' is positioned above the tower. To the right, a light blue box represents an 'MV/LV transformer (50 kV; 50 Hz)' with a '(125 kV; lightning)' protection level. Above this transformer is a white box labeled 'MV feeding'. An orange box labeled 'MV overhead line' is shown to the right of the transformer. A green horizontal line represents the ground. A cyan box labeled 'Equipotential conductor' is connected to the RBS tower and the ground. A red box labeled 'EPR 50 kV max' is connected to the RBS tower. Another red box labeled 'EPR <1500 V' is connected to the ground. The diagram is labeled 'K.57(16)\_F05' in the bottom right corner. + +Diagram of MV power feeding of RBS + +Figure 5 – MV power feeding of RBS + +![Diagram of connection to a telecommunication network via optic fibre](41a438d7e4adc17c3a4005e7c9500091_img.jpg) + +This diagram illustrates the electrical installation for a connection to a telecommunication network via optic fibre. On the left, a lattice tower represents the RBS, with a yellow lightning rod at its top. A grey box labeled 'RBS' is positioned above the tower. To the right, a yellow box represents a 'Copper/Optical conversion cabinet'. Below it, a cyan box labeled 'Equipotential conductor' is connected to the RBS tower and the ground. A red box labeled 'EPR 50 kV max' is connected to the RBS tower. A yellow box labeled 'Copper cable' is connected to the conversion cabinet. An orange box labeled 'Optical cable without metallic screen' is also connected to the conversion cabinet. A yellow box labeled 'EPR <650 V' is connected to the ground. The diagram is labeled 'K.57(16)\_F06' in the bottom right corner. + +Diagram of connection to a telecommunication network via optic fibre + +Figure 6 – Connection to a telecommunication network via optic fibre + +![Schematic diagram showing the connection of an RBS to a telecommunication network via a radio link. On the left, a tower supports an RBS and a yellow rectangular component. A yellow lightning bolt symbol represents the radio link connecting to a receiver on the right. The right side shows a blue component connected to a copper cable. Red boxes indicate Earth Potential Rise (EPR) values: 'EPR 50 kV max' on the left and 'EPR <650 V' on the right. Reference code K.57(16)_F07 is at the bottom right.](8fbdfc3d17fb1dae7b2d8f5a287fa9fc_img.jpg) + +RBS +Radio link +Copper cable +EPR 50 kV max +EPR <650 V +K.57(16)\_F07 + +Schematic diagram showing the connection of an RBS to a telecommunication network via a radio link. On the left, a tower supports an RBS and a yellow rectangular component. A yellow lightning bolt symbol represents the radio link connecting to a receiver on the right. The right side shows a blue component connected to a copper cable. Red boxes indicate Earth Potential Rise (EPR) values: 'EPR 50 kV max' on the left and 'EPR <650 V' on the right. Reference code K.57(16)\_F07 is at the bottom right. + +**Figure 7 – Connection to a telecommunication network via radio link** + +![Technical drawing of an RBS installation on a power tower. Labels on the left include 'Safety ladder with cable fixing rack', 'Antenna cable', 'Power-feeding cable in protection tube', and 'Protection tube'. Labels on the right include 'Outdoor', 'Isolation transformer in protection cabinet', 'RBS cabinet', 'Platform for citytalk', and 'Removable ladder'. Dimensions shown are '100' for a vertical gap, '4000' for the platform height, and '~ 7250' for the base width. Reference code K.57(16)_F08 is at the bottom right.](2cde062fd82833415971a8bd1a2cafab_img.jpg) + +Safety ladder +with cable fixing rack +Antenna cable +Power-feeding cable +in protection tube +100 +Protection tube +~ 7250 +Outdoor +Isolation transformer +in protection cabinet +RBS cabinet +Platform for citytalk +Removable ladder +4000 +K.57(16)\_F08 + +Technical drawing of an RBS installation on a power tower. Labels on the left include 'Safety ladder with cable fixing rack', 'Antenna cable', 'Power-feeding cable in protection tube', and 'Protection tube'. Labels on the right include 'Outdoor', 'Isolation transformer in protection cabinet', 'RBS cabinet', 'Platform for citytalk', and 'Removable ladder'. Dimensions shown are '100' for a vertical gap, '4000' for the platform height, and '~ 7250' for the base width. Reference code K.57(16)\_F08 is at the bottom right. + +**Figure 8 – Elevated location of RBS in power tower** + +# Appendix I + +## Guide on the coordination of the isolation level required for power supply circuit and the potential rise of power line towers + +(This appendix does not form an integral part of this Recommendation.) + +## I.1 Scope of the investigation + +The tower-earthing potential rise (T-EPR) investigations presented in this appendix aim at sensitivity analysis performed by a multiconductor solution technique [b-Sollerkvist], to provide guidance on the identification of the potential relevant to given conditions in practice. + +The analysis performed covers the following optional conditions: + +- 1) Length, $L$ , of the power line (km): 15 or 60. +- 2) Location of the fault: near the origin (km 1), middle (km $L/2$ ) or near the end (km $L - 1$ ) of the line, and also step-like varying. +- 3) Earthing resistance of the substations at the lines origin/end ( $\Omega$ ): 0.1/0.1 or 0.1/1. +- 4) Way of supply: single end ( $1 \times 10$ kA) or both ends ( $2 \times 5$ kA). +- 5) Shield-wire (sw) and counterpoise (cp) options: two sw, only one sw or one sw + cp. +- 6) Earthing resistance of the tower ( $\Omega$ )/soil resistivity ( $\Omega\text{m}$ ): 8/50, 25/500 or 50/2500. +- 7) Mean span between the towers. + +The results are related to phase-to-earth fault current with a magnitude of 10 kA, which is considered as a base. Considering that the investigated phenomenon is practically linear, the obtained T-EPR values can be recalculated to any actual earth fault current proportionally to the ratio of that earth fault current and the 10-kA basic current. + +## I.2 Investigated options, parameters + +### I.2.1 Line structure options + +The conductor arrangements of the investigated 400-kV power lines are identified in Figure I.1. The two-line arrangements shown in Figure I.1 are investigated according to the following three options: + +- A Horizontal phase conductor arrangement with **two shield-wires (sw)** (Figure I.1 a); +- B Compact triangular phase conductor arrangement with **one shield-wire (sw)** (Figure I.1 b); +- C As in point B but with **one shield-wire and one counterpoise (cp)**. + +The counterpoise is a bare copper wire of $35\text{ mm}^2$ laid along the route of the line in about 0.5-m depth. The towers are not metallically connected to the cp. However, the spark gaps, installed between the tower earthing and the cp, are striking and connecting the tower to the cp when T-EPR exceeds about 3 kV. Thus, for this condition, no connection is assumed between the tower earthing and the cp, except at the faulty tower. + +![Diagram of a line structure with twin shield-wires (case A). The diagram shows a tower with a total height of 12.72 m (b_n + 50°). The top of the tower has a horizontal width of 8.8 m, with 4.6 m on each side. The phase conductors are suspended 4.0 m below the top. The shield wires are suspended 3.8 m below the top. The base of the tower is shown with hatching.](9c6461e1e94afae4dec455e69a2ce152_img.jpg) + +Diagram of a line structure with twin shield-wires (case A). The diagram shows a tower with a total height of 12.72 m (b\_n + 50°). The top of the tower has a horizontal width of 8.8 m, with 4.6 m on each side. The phase conductors are suspended 4.0 m below the top. The shield wires are suspended 3.8 m below the top. The base of the tower is shown with hatching. + +Structure of the phase conductor system: $3 \times (3 \times 593) \text{ mm}^2$ + Structure of the shield (earth) conductor system: $2 \times 142 \text{ mm}^2$ + $b_n + 50^\circ = 12.72 \text{ m}$ + +**a) Arrangement of line with twin shield-wires (case A)** + +![Diagram of a line structure with a single shield-wire (case B). The diagram shows a tower with a total height of 34800 mm. The phase conductors are suspended at a height of 19900 mm. The shield wire is suspended at a height of 3418 mm. The counterpoise is shown at a depth of 3510 mm. The base of the tower is shown with hatching. The diagram is labeled K.57(16)_FI.1.](8fa679f79a1bb1f527cba9f29e784e89_img.jpg) + +Diagram of a line structure with a single shield-wire (case B). The diagram shows a tower with a total height of 34800 mm. The phase conductors are suspended at a height of 19900 mm. The shield wire is suspended at a height of 3418 mm. The counterpoise is shown at a depth of 3510 mm. The base of the tower is shown with hatching. The diagram is labeled K.57(16)\_FI.1. + +Structure of the phase conductor system: $3 \times (3 \times 593) \text{ mm}^2$ + Structure of the shield (earth) conductor system: $1 \times 241 \text{ mm}^2$ + Counterpoise can additionally be applied in a depth of 50 cm. + +**b) Arrangement of line with single shield-wire (case B) + which may be equipped with counterpoise as well (case C)** + +**Figure I.1 – Line structures assumed in the investigations + (normal span: 333 m)** + +The assumed mean span between the towers is 333 m (1/3 km). Investigations have also been made for mean spans of 200 m and 500 m for the checking of the effect of the span length. + +The simulation calculations have been performed for line lengths of: + +- Code L15: "short line" of 15 km; +- Code L60: "long line" of 60 km. + +### I.2.2 Parameter options + +#### I.2.2.1 Substation earthing + +The following two options are simulated regarding the earthing resistances of the substations at the line ends: + +- Case code S1: low resistance at both ends, i.e., 0.1 Ω/0.1 Ω; +- Case code S2: low resistance at the origin (S end at km 0) and higher impedance at the other (R at km L) end, i.e., 0.1 Ω/1 Ω. + +#### I.2.2.2 Tower-earthing resistance and specific earth resistivity + +The specific resistivity of the earth affects two kind of parameters used in the simulations. The specific resistivity of the surface soil layer essentially influences the resistance of the tower earthing. The earthing resistance – assuming a given earthing electrode structure – is, in principle, proportional to the specific resistivity of the soil embedding the electrode system. + +The specific resistivity of the deeper earth layer has a certain effect on the series self- and mutual impedances, both with earth return, of the line. The effect is quite small for self-impedance and also for mutual impedance, when the span between the conductors is not big, such as the spacing between the phase and shield-wires. + +It follows that no strict but certain correlation should be assumed between tower-earthing resistance and the specific earth resistance. Therefore, the following options are considered in the simulation study: + +| Case code | Resistivity | | +|-----------|--------------------|---------------| +| | Tower earthing [Ω] | Specific [Ωm] | +| R1 | 8 | 50 | +| R2 | 25 | 500 | +| R3 | 50 | 2500 | + +#### I.2.2.3 Fault locations + +The calculations have been performed for every simulated option for fault location at the middle (km L/2) of the line. + +In case of one-sided ( $1 \times 10$ kA) current injection, the following fault locations have also been studied: + +- at 1-km distance from each line end; +- varying with 1-km steps for the 15-km long line and 2-km steps for the 60-km long line. + +#### I.2.2.4 Magnitude and way of fault current injection + +The potential rise is linked with the $I_0$ zero-sequence current component. In case of phase-to-earth fault, the $3I_0$ zero-sequence current is equal to the fault current at the faulty point. In the studies $3I_0 = 10$ kA fault current magnitude is assumed at the faulty point. Along the line, $I_0$ current is assumed in each phase, thus the effects of the positive and negative sequence current components are neglected. Practically it means the consideration of the "average" effects between the phase and shield-wires, or in other words the neglecting of the small differences due to the fault occurrences in different phases. + +Regarding the current distribution between the line sections at both sides of the faulty point, the following two extreme conditions are simulated: + +- $1 \times 10$ kA current flow only in one direction, i.e., between km 0 and the faulty point; + +- $2 \times 5$ kA current flow half-by-half, i.e., $3I_0 = 5$ kA both between km 0 and the faulty point, and the faulty point and km L line sections. + +In an actual case, the current distribution is affected by the relative location of the faulty point, but it is basically determined by the zero-sequence impedances of the substations, which is highly influenced by the transformers with earthed neutral located in the substations at the line ends. However, the one-side current flow occurs, at least temporarily, during the tripping process, due to the non-simultaneous switch-off at both ends of the faulty line. + +## **I.3 Analysis of the results** + +### **I.3.1 Qualitative analysis** + +First of all, a qualitative analysis of the results on the tower potential rise was undertaken to identify the relative importance of the different conditions listed in clause I.1. The key result is the potential of the shield-wire(s), because, due to the metallic connection between tower and shield-wires, the potential rise of a given tower is identical with the potential of the shield-wire at the place of the tower in question. + +This qualitative analysis is carried out through the use of plots containing the most representative results of the simulations. + +The highest potential rise occurs, of course, at the faulty tower (see Figures I.2, I.3 and I.4). The shield-wire potential is decreasing with the increase of the distance from the faulty point. The shield-wire potential tends to drop to zero in that side of the line from where no zero-sequence current is fed to the fault (see the right side of the plots in Figures I.2 and I.3). In contrast to this, the shield-wire potential tends to drop to zero at first, and behind this section it is increasing, when approaching the substation, which feeds zero-sequence current to the fault (see the left side of the plots in Figures I.2 and I.3 and also both sides of the plots in Figure I.4). + +Regarding the effect of the fault location, it can be stated that the potential rise of the faulty tower practically does not vary except near the line ends (in the end-effect zones), where the potential decreases to approach the potential rise relevant to the substation earthing (see Figure I.5). It is worth mentioning that this decreasing tendency is strictly valid only with the assumption that the earth fault current magnitude is constant. In practice, magnitude of the earth fault current increases when the fault occurs closer to the substation. These counter-effects can mainly compensate each other in practical cases. + +The effect of the mean span on the tower potential rise of the faulty tower vs. the fault location is demonstrated for line structure having only one shield-wire in Figure I.6. It can be seen that the tower potential rise increases with the increase in the mean span. + +For the sake of completeness, the shield-wire current profile is plotted in Figure I.7. The following tendencies can be observed, when zero-sequence current ( $3I_0 = 10$ kA) is fed only from one (left) side: + +- Shield-wire current is flowing in both directions, but significantly higher on the feeding side. +- Shield-wire current tends to drop to zero in that side of the line from where no zero-sequence current is fed to the fault. + +The shield-wire current decreases to its induced steady value first, and behind this, generally increases in the end-effect zone close to the substation, which feeds the zero-sequence current to the fault. + +![Graph (a) showing shield-wire potential profile vs. length for a 15 km line. The y-axis is potential in kV (0 to 12) and the x-axis is distance in km (0 to 15). Three curves are shown for different tower earthing resistances: 50 Ω (solid green), 25 Ω (dashed black), and 8 Ω (dotted red). The potential peaks at the fault location (7.5 km) and returns to zero at the substation (0 km) and the far end (15 km).](60e9207be66a64332619bb4b667fe67b_img.jpg) + +**a) Line length: L = 15 km** + +Graph (a) showing shield-wire potential profile vs. length for a 15 km line. The y-axis is potential in kV (0 to 12) and the x-axis is distance in km (0 to 15). Three curves are shown for different tower earthing resistances: 50 Ω (solid green), 25 Ω (dashed black), and 8 Ω (dotted red). The potential peaks at the fault location (7.5 km) and returns to zero at the substation (0 km) and the far end (15 km). + +![Graph (b) showing shield-wire potential profile vs. length for a 60 km line. The y-axis is potential in kV (0 to 12) and the x-axis is distance in km (0 to 60). Three curves are shown for different tower earthing resistances: 50 Ω (solid green), 25 Ω (dashed black), and 8 Ω (dotted red). The potential peaks at the fault location (30 km) and returns to zero at the substation (0 km) and the far end (60 km).](ed75e80b1e08237f7e90b65357de84d5_img.jpg) + +**b) Line length: L = 60 km** + +K.57(16)\_FI.2 + +Graph (b) showing shield-wire potential profile vs. length for a 60 km line. The y-axis is potential in kV (0 to 12) and the x-axis is distance in km (0 to 60). Three curves are shown for different tower earthing resistances: 50 Ω (solid green), 25 Ω (dashed black), and 8 Ω (dotted red). The potential peaks at the fault location (30 km) and returns to zero at the substation (0 km) and the far end (60 km). + +B 400-kV line with 1 shield-wire without counterpoise + S1 Substation earthing: 0.1 Ω/0.1 Ω + F2 Fault location: L/2 km (F2) + 1 × 10 kA current flow, only from the left side of the faulty point + +**Figure I.2 – Shield-wire potential profile vs. length, parameter: +Tower-earthing resistance** + +![Graph showing shield-wire potential profile (kV) versus normalized length scale parameter (km) for two line lengths: 60 km and 15 km. The 60 km curve (solid black) peaks at approximately 4.7 kV at 0.5 km, while the 15 km curve (dashed green) peaks at approximately 4.5 kV at 0.5 km. Both curves start at 0.5 kV at 0 km and return to 0 kV at 1 km.](0f79a59f3766fc341ff688a23692c1d9_img.jpg) + +B 400-kV line with 1 shield-wire without counterpoise + S1 Substation earthing: 0.1 Ω/0.1 Ω + F2 Fault location: L/2 km (F2) + R1 Tower-earthing resistance: 8 Ω + 1 × 10 kA current flow, only from the left side of the faulty point + +Graph showing shield-wire potential profile (kV) versus normalized length scale parameter (km) for two line lengths: 60 km and 15 km. The 60 km curve (solid black) peaks at approximately 4.7 kV at 0.5 km, while the 15 km curve (dashed green) peaks at approximately 4.5 kV at 0.5 km. Both curves start at 0.5 kV at 0 km and return to 0 kV at 1 km. + +K.57(16)\_FI.3 + +**Figure I.3 – Shield-wire potential profile vs. length, +with normalized length scale parameter: Line length** + +![Graph (a) showing shield-wire potential (kV) vs. length (km) for a 1 x 10 kA current flow. The y-axis ranges from 0 to 9 kV, and the x-axis ranges from 0 to 15 km. A solid black line represents the potential profile, peaking at approximately 8.2 kV at 7.5 km (the fault point). Two dashed blue lines, labeled S1 and S2, represent the potential profiles at the substation locations (approximately 10 km and 13 km). The potential decreases linearly from the fault point towards the substation locations.](9ce50bc10864dc86e1cdee4be08f1897_img.jpg) + +Graph (a) showing shield-wire potential (kV) vs. length (km) for a 1 x 10 kA current flow. The y-axis ranges from 0 to 9 kV, and the x-axis ranges from 0 to 15 km. A solid black line represents the potential profile, peaking at approximately 8.2 kV at 7.5 km (the fault point). Two dashed blue lines, labeled S1 and S2, represent the potential profiles at the substation locations (approximately 10 km and 13 km). The potential decreases linearly from the fault point towards the substation locations. + +a) $1 \times 10$ kA current flow, only in the left side of the faulty point + +![Graph (b) showing shield-wire potential (kV) vs. length (km) for a 2 x 5 kA current flow. The y-axis ranges from 0 to 9 kV, and the x-axis ranges from 0 to 15 km. A solid black line represents the potential profile, peaking at approximately 8.2 kV at 7.5 km (the fault point). Two dashed blue lines, labeled S1 and S2, represent the potential profiles at the substation locations (approximately 10 km and 13 km). The potential decreases linearly from the fault point towards the substation locations. The graph is labeled K.57(16)_FI.4.](485c57a6add7e0bd7898009db1179ee6_img.jpg) + +Graph (b) showing shield-wire potential (kV) vs. length (km) for a 2 x 5 kA current flow. The y-axis ranges from 0 to 9 kV, and the x-axis ranges from 0 to 15 km. A solid black line represents the potential profile, peaking at approximately 8.2 kV at 7.5 km (the fault point). Two dashed blue lines, labeled S1 and S2, represent the potential profiles at the substation locations (approximately 10 km and 13 km). The potential decreases linearly from the fault point towards the substation locations. The graph is labeled K.57(16)\_FI.4. + +b) $2 \times 5$ kA current flow, in both sides of the faulty point + +B 400-kV line with 1 shield-wire without counterpoise + F2 Fault location: $L/2$ km (F2) + R2 Tower-earthing resistance: $25 \Omega$ + +**Figure I.4 – Shield-wire potential vs. length profile, parameter: + Earthing resistances of the substations + $S1 = 0.1 \Omega/0.1 \Omega$ , $S2 = 0.1 \Omega/1 \Omega$** + +![Graph (a) showing Tower potential rise (kV) vs. Fault location (km) for a line length L = 15 km. The y-axis ranges from 0 to 9 kV, and the x-axis ranges from 0 to 15 km. The curve starts at approximately 3.8 kV at 1 km, rises to a peak of about 8.2 kV between 8 and 9 km, and then falls back to approximately 3.8 kV at 14 km.](645bea0b27d63e4a9a300af5793ae7d2_img.jpg) + +Graph (a) showing Tower potential rise (kV) vs. Fault location (km) for a line length L = 15 km. The y-axis ranges from 0 to 9 kV, and the x-axis ranges from 0 to 15 km. The curve starts at approximately 3.8 kV at 1 km, rises to a peak of about 8.2 kV between 8 and 9 km, and then falls back to approximately 3.8 kV at 14 km. + +a) Line length: $L = 15 \text{ km}$ + +![Graph (b) showing Tower potential rise (kV) vs. Fault location (km) for a line length L = 60 km. The y-axis ranges from 0 to 9 kV, and the x-axis ranges from 0 to 15 km. The curve starts at approximately 3.8 kV at 1 km, rises to a peak of about 8.2 kV between 1 and 2 km, remains relatively flat around 8 kV until 13 km, and then falls back to approximately 3.8 kV at 14 km.](5500ab73cf84ccc0055eecf28889b4db_img.jpg) + +Graph (b) showing Tower potential rise (kV) vs. Fault location (km) for a line length L = 60 km. The y-axis ranges from 0 to 9 kV, and the x-axis ranges from 0 to 15 km. The curve starts at approximately 3.8 kV at 1 km, rises to a peak of about 8.2 kV between 1 and 2 km, remains relatively flat around 8 kV until 13 km, and then falls back to approximately 3.8 kV at 14 km. + +b) Line length: $L = 60 \text{ km}$ + +K.57(16)\_FI.5 + +B 400-kV line with 1 shield-wire without counterpoise + S1 Substation earthing: $0.1 \Omega/0.1 \Omega$ + R2 Tower-earthing resistance: $25 \Omega$ + $1 \times 10 \text{ kA}$ current flow, only from the left side of the faulty point + +**Figure I.5 – Tower potential rise of the faulty tower vs. the fault location** + +![Graph (a) showing tower potential rise (kV) vs. fault location (km) for a line length L = 15 km. The y-axis ranges from 0 to 12 kV, and the x-axis ranges from 0 to 15 km. Three curves are shown for different mean spacings: 200 m (dash-dot line), 333 m (solid line), and 500 m (dashed line). All curves show a peak potential rise around the middle of the line (7.5 km). The 200 m spacing curve has the highest peak at approximately 10 kV, while the 500 m spacing curve has the lowest peak at approximately 6 kV.](97f61e67792478fb6ce089868e503063_img.jpg) + +Graph (a) showing tower potential rise (kV) vs. fault location (km) for a line length L = 15 km. The y-axis ranges from 0 to 12 kV, and the x-axis ranges from 0 to 15 km. Three curves are shown for different mean spacings: 200 m (dash-dot line), 333 m (solid line), and 500 m (dashed line). All curves show a peak potential rise around the middle of the line (7.5 km). The 200 m spacing curve has the highest peak at approximately 10 kV, while the 500 m spacing curve has the lowest peak at approximately 6 kV. + +a) Line length $L = 15$ km + +![Graph (b) showing tower potential rise (kV) vs. fault location (km) for a line length L = 60 km. The y-axis ranges from 0 to 12 kV, and the x-axis ranges from 0 to 60 km. Three curves are shown for different mean spacings: 200 m (dash-dot line), 333 m (solid line), and 500 m (dashed line). The curves are relatively flat across the middle of the line. The 200 m spacing curve is the highest at approximately 9.5 kV, and the 500 m spacing curve is the lowest at approximately 6 kV. There are sharp drops at the ends of the line (0 km and 60 km).](2a25e8bc21554c0efceda1a8ccf57db3_img.jpg) + +Graph (b) showing tower potential rise (kV) vs. fault location (km) for a line length L = 60 km. The y-axis ranges from 0 to 12 kV, and the x-axis ranges from 0 to 60 km. Three curves are shown for different mean spacings: 200 m (dash-dot line), 333 m (solid line), and 500 m (dashed line). The curves are relatively flat across the middle of the line. The 200 m spacing curve is the highest at approximately 9.5 kV, and the 500 m spacing curve is the lowest at approximately 6 kV. There are sharp drops at the ends of the line (0 km and 60 km). + +b) Line length $L = 60$ km + +K.57(16)\_FI.6 + +B 400-kV line with 1 shield-wire without counterpoise + S1 Substation earthing: $0.1 \Omega/0.1 \Omega$ + R2 Tower-earthing resistance: $25 \Omega$ + $1 \times 10$ kA current flow, only from the left side of the faulty point + +**Figure I.6 – Effect of the mean span (parameter of the curves) on the tower potential rise of the faulty tower vs. the fault location** + +![Figure I.7: Shield-wire current profile vs. length. The figure contains two graphs, (a) and (b). Graph (a) shows the current profile for a 15 km line length, with the x-axis ranging from 0 to 15 km and the y-axis (Current in Amperes) ranging from 0 to 8000 A. Graph (b) shows the current profile for a 60 km line length, with the x-axis ranging from 0 to 60 km and the y-axis ranging from 0 to 8000 A. Both graphs show three curves for different tower earthing resistances: 50 Ω (green solid line), 25 Ω (black solid line), and 8 Ω (red dotted line). In both cases, the current increases from the left side of the fault (at 0 km) towards the fault location (at 7.5 km for the 15 km line and 30 km for the 60 km line), where it peaks and then drops sharply. After the fault, the current decreases towards the right side of the line. The peak current is higher for lower earthing resistance. The label 'K.57(16)_FI.7' is present in the bottom right of graph (b).](bfb6d182d624680db577069bbc0b2a93_img.jpg) + +a) Line length: $L = 15$ km + +b) Line length: $L = 60$ km + +B 400-kV line with 1 shield-wire without counterpoise +S1 Substation earthing: $0.1 \ \Omega / 0.1 \ \Omega$ +F2 Fault location: $L/2$ km (F2) + $1 \times 10$ kA current flow, only from the left side of the faulty point + +Figure I.7: Shield-wire current profile vs. length. The figure contains two graphs, (a) and (b). Graph (a) shows the current profile for a 15 km line length, with the x-axis ranging from 0 to 15 km and the y-axis (Current in Amperes) ranging from 0 to 8000 A. Graph (b) shows the current profile for a 60 km line length, with the x-axis ranging from 0 to 60 km and the y-axis ranging from 0 to 8000 A. Both graphs show three curves for different tower earthing resistances: 50 Ω (green solid line), 25 Ω (black solid line), and 8 Ω (red dotted line). In both cases, the current increases from the left side of the fault (at 0 km) towards the fault location (at 7.5 km for the 15 km line and 30 km for the 60 km line), where it peaks and then drops sharply. After the fault, the current decreases towards the right side of the line. The peak current is higher for lower earthing resistance. The label 'K.57(16)\_FI.7' is present in the bottom right of graph (b). + +**Figure I.7 – Shield-wire current profile vs. length** + +### I.3.2 Quantitative analysis + +The studied conditions and parameters can be classified accordingly to their relative importance on the tower potential rise magnitudes into the following three classes: + +- a) Negligible conditions and parameters are: +- Length of the line; +(See Figures I.3 and I.8, which indicate only a very small increase in T-EPR for shorter line.) + - Earthing resistance of the substations; +(See Figures I.4 and I.9.) + - Single ( $1 \times 10$ kA) or double ( $2 \times 5$ kA) sided fault (zero-sequence) current flow. +(See Figure I.10.) + +b) Deciding conditions and parameters are: + +- Earthing resistance of the towers (average); +(See Figures I.2 and I.8.) +- Shield-wire number (one or two) and use of counterpoise. +(See Figure I.8.) + +It is worth mentioning that the magnitude of the fault current belongs also to the deciding parameter. However, it is a design parameter, which should correspond to the actual value (range) when estimating the T-EPR relevant to a given case. + +c) Corrective condition is the span between the towers. Its relative importance is demonstrated in Figures I.11 and I.12 for line lengths of 15 km and 60 km, respectively. The values of correction factor for the calculations of the tower potential of lines with different spans are given in Table I.2. + +It is worth mentioning that the corrections needed in the tower potential rise due to the differences in the span are less than $\pm 5\%$ for lines equipped with shield-wire(s) and counterpoise, and less than $\pm 25\%$ for lines equipped only with shield-wire(s). + +The tower potential rise values obtained from the simulations are given for the deciding conditions in Table I.1. These values are related to 10-kA earth fault current and span of 333 m as reference conditions. They can be recalculated to currents other than 10 kA proportionally to the current magnitude. Similarly, tower potential rise can be recalculated to span values other than the mean of 333 m, by its multiplication with the correction factors given in Table I.2. + +**Table I.1 – Potential rise of the faulty tower for the deciding conditions and parameters per 10-kA earth fault current** + +| Earthing resistance [ $\Omega$ ] | Shield-wire configuration | | | | | | +|----------------------------------|---------------------------|--------|-------|--------|-----------|--------| +| | 1 sw | | 2 sw | | 1 sw + cp | | +| | [kV] | [Deg.] | [kV] | [Deg.] | [kV] | [Deg.] | +| 8 | 4.663 | 31.40 | 3.237 | 22.62 | 0.872 | 19.68 | +| 25 | 8.208 | 32.45 | 5.589 | 25.13 | 2.290 | 20.08 | +| 50 | 11.413 | 37.70 | 7.432 | 31.32 | 4.316 | 22.63 | +| sw | shield-wire | | | | | | +| cp | counterpoise | | | | | | + +**Table I.2 – Correction factors for the tower potential rise of lines with different spans +(Base: The tower voltage for a 333-m span)** + +| Earthing wire structure | Spacing [m] | Line lengths [km] | | | | | | +|-------------------------|-------------|----------------------------------------|------|------|----------------------------------------|------|------| +| | | 15 | | | 60 | | | +| | | Tower-earthing resistance [ $\Omega$ ] | | | Tower-earthing resistance [ $\Omega$ ] | | | +| | | 8 | 25 | 50 | 8 | 25 | 50 | +| 1 sw | 200 | 0.77 | 0.76 | 0.77 | 0.78 | 0.77 | 0.77 | +| | 333 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | +| | 500 | 1.23 | 1.24 | 1.18 | 1.22 | 1.22 | 1.22 | +| 2 sw | 200 | 0.77 | 0.76 | 0.80 | 0.77 | 0.77 | 0.77 | +| | 333 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | +| | 500 | 1.24 | 1.21 | 1.14 | 1.22 | 1.22 | 1.22 | +| 1 sw + 1 cp | 200 | 0.95 | 0.92 | 0.89 | 0.95 | 0.92 | 0.89 | +| | 333 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | +| | 500 | 1.03 | 1.06 | 1.08 | 1.03 | 1.05 | 1.08 | + +NOTE – 1) 400-kV line configuration. + +2) Fault location: L/2 km. + +3) $2 \times 5$ kA current flow, only from the left side of the faulty point. + +4) Substation earthing: $0.1 \Omega/0.1 \Omega$ . + +![Bar chart and data table for line length L = 15 km. The chart shows potential rise in kV for three tower configurations (1 sw, 2 sw, 1 sw + cp) across three earthing resistances (8 Ω, 25 Ω, 50 Ω). The data table provides the exact values.](a2dcc4a0703102026ec86e82caa4985e_img.jpg) + +1 × 10 kA, L = 15 km, 0.1 Ω/0.1 Ω + +| | 1 sw | 2 sw | 1 sw + cp | +|------|--------|-------|-----------| +| 8 Ω | 4.663 | 3.237 | 0.872 | +| 25 Ω | 8.208 | 5.589 | 2.29 | +| 50 Ω | 11.413 | 7.432 | 4.316 | + +Bar chart and data table for line length L = 15 km. The chart shows potential rise in kV for three tower configurations (1 sw, 2 sw, 1 sw + cp) across three earthing resistances (8 Ω, 25 Ω, 50 Ω). The data table provides the exact values. + +a) Line length: L = 15 km + +![Bar chart and data table for line length L = 60 km. The chart shows potential rise in kV for three tower configurations (1 sw, 2 sw, 1 sw + cp) across three earthing resistances (8 Ω, 25 Ω, 50 Ω). The data table provides the exact values.](7119b28e39fa3784606bf8b8f44e4f9d_img.jpg) + +1 × 10 kA, L = 60 km, 0.1 Ω/0.1 Ω + +| | 1 sw | 2 sw | 1 sw + cp | +|------|--------|-------|-----------| +| 8 Ω | 4.64 | 3.2 | 0.87 | +| 25 Ω | 7.86 | 5.342 | 2.259 | +| 50 Ω | 10.803 | 7.28 | 4.157 | + +K.57(16)\_FI.8 + +Bar chart and data table for line length L = 60 km. The chart shows potential rise in kV for three tower configurations (1 sw, 2 sw, 1 sw + cp) across three earthing resistances (8 Ω, 25 Ω, 50 Ω). The data table provides the exact values. + +b) Line length: L = 60 km + +S1 Substation earthing: 0.1 Ω/0.1 Ω + +F2 Fault location: L/2 km (F2) + +1 × 10 kA current flow, only from the left side of the faulty point + +**Figure I.8 – Potential rise of the faulty tower for different tower-earthing resistances and shield-wire/counterpoise options** + +![Bar chart for fault location at km 1 showing potential rise in kV for different tower-earthing resistances (8, 25, 50 ohms) and substation earthing resistance options (0.1/0.1 and 0.1/1).](bafe3665fa89ba09857af5a2532c79fe_img.jpg) + +S, $1 \times 10$ kA, $L = 15$ km + +| | Substation earthing resistance: 0.1/0.1 | Substation earthing resistance: 0.1/1 | +|-------------|-----------------------------------------|---------------------------------------| +| 8 $\Omega$ | 1.914 | 1.914 | +| 25 $\Omega$ | 2.259 | 2.258 | +| 50 $\Omega$ | 2.423 | 2.419 | + +Bar chart for fault location at km 1 showing potential rise in kV for different tower-earthing resistances (8, 25, 50 ohms) and substation earthing resistance options (0.1/0.1 and 0.1/1). + +a) Fault location at km 1 + +![Bar chart for fault location at the middle of the line showing potential rise in kV for different tower-earthing resistances (8, 25, 50 ohms) and substation earthing resistance options (0.1/0.1 and 0.1/1).](ec36a1ba48e13289c395fab4a7730bdb_img.jpg) + +M, $1 \times 10$ kA, $L = 15$ km + +| | Substation earthing resistance: 0.1/0.1 | Substation earthing resistance: 0.1/1 | +|-------------|-----------------------------------------|---------------------------------------| +| 8 $\Omega$ | 3.237 | 3.232 | +| 25 $\Omega$ | 5.589 | 5.492 | +| 50 $\Omega$ | 7.432 | 7.273 | + +Bar chart for fault location at the middle of the line showing potential rise in kV for different tower-earthing resistances (8, 25, 50 ohms) and substation earthing resistance options (0.1/0.1 and 0.1/1). + +b) Fault location at the middle of the line + +![Bar chart for fault location at km 14 showing potential rise in kV for different tower-earthing resistances (8, 25, 50 ohms) and substation earthing resistance options (0.1/0.1 and 0.1/1).](1acc7c1338d89d86a162eb4ebedae856_img.jpg) + +R, $1 \times 10$ kA, $L = 15$ km + +| | Substation earthing resistance: 0.1/0.1 | Substation earthing resistance: 0.1/1 | +|-------------|-----------------------------------------|---------------------------------------| +| 8 $\Omega$ | 2.062 | 2.914 | +| 25 $\Omega$ | 2.414 | 3.768 | +| 50 $\Omega$ | 2.571 | 4.140 | + +Bar chart for fault location at km 14 showing potential rise in kV for different tower-earthing resistances (8, 25, 50 ohms) and substation earthing resistance options (0.1/0.1 and 0.1/1). + +K.57(16)\_Fl.9 + +c) Fault location at km 14 + +A 400-kV line with 2 shield-wires without counterpoise +R2 Tower-earthing resistance: 25 $\Omega$ +L15 Line length $L = 15$ km + $1 \times 10$ kA current flow, only from the left side of the faulty point + +**Figure I.9 – Potential rise of the faulty tower for different tower-earthing resistance and substation earthing resistance options** + +![Bar chart showing potential rise in kV for substation earthing resistances S1 = 0.1 Ω/0.1 Ω. The y-axis ranges from 0 to 8 kV. The x-axis shows three earthing resistance options: 8 Ω, 25 Ω, and 50 Ω. For each option, two bars are shown: 1 × 10 kA (solid grey) and 2 × 5 kA (hatched). The values are approximately 3.2 kV for 8 Ω, 5.6 kV for 25 Ω, and 7.4 kV for 50 Ω.](48a08e5cabec8b75386679d8a57dec3e_img.jpg) + +M, 0.1/0.1, l = 15 km + +| | 8 Ω | 25 Ω | 50 Ω | +|-----------|-------|-------|-------| +| 1 × 10 kA | 3.237 | 5.589 | 7.432 | +| 2 × 5 kA | 3.236 | 5.589 | 7.431 | + +Bar chart showing potential rise in kV for substation earthing resistances S1 = 0.1 Ω/0.1 Ω. The y-axis ranges from 0 to 8 kV. The x-axis shows three earthing resistance options: 8 Ω, 25 Ω, and 50 Ω. For each option, two bars are shown: 1 × 10 kA (solid grey) and 2 × 5 kA (hatched). The values are approximately 3.2 kV for 8 Ω, 5.6 kV for 25 Ω, and 7.4 kV for 50 Ω. + +a) Substation earthing resistances S1 = 0.1 Ω/0.1 Ω + +![Bar chart showing potential rise in kV for substation earthing resistances S2 = 0.1 Ω/1 Ω. The y-axis ranges from 0 to 8 kV. The x-axis shows three earthing resistance options: 8 Ω, 25 Ω, and 50 Ω. For each option, two bars are shown: 1 × 10 kA (solid grey) and 2 × 5 kA (hatched). The values are approximately 3.2 kV for 8 Ω, 5.5 kV for 25 Ω, and 7.2 kV for 50 Ω.](6f10f5cbc920e8c4340d869aae0f1f58_img.jpg) + +M, 0.1/1, l = 15 km + +| | 8 Ω | 25 Ω | 50 Ω | +|-----------|-------|-------|-------| +| 1 × 10 kA | 3.232 | 5.492 | 7.273 | +| 2 × 5 kA | 3.275 | 5.512 | 7.217 | + +K.57(16)\_Fl.10 + +Bar chart showing potential rise in kV for substation earthing resistances S2 = 0.1 Ω/1 Ω. The y-axis ranges from 0 to 8 kV. The x-axis shows three earthing resistance options: 8 Ω, 25 Ω, and 50 Ω. For each option, two bars are shown: 1 × 10 kA (solid grey) and 2 × 5 kA (hatched). The values are approximately 3.2 kV for 8 Ω, 5.5 kV for 25 Ω, and 7.2 kV for 50 Ω. + +b) Substation earthing resistances S2 = 0.1 Ω/1 Ω + +A 400-kV line with 2 shield-wire without counterpoise + F2 Fault location: L/2 km (F2) + +**Figure I.10 – Potential rise of the faulty tower for single (1 × 10 kA) or double (2 × 5 kA) sided fault current flow and tower-earthing resistance options** + +![Bar chart and data table for 1 shield-wire tower potential rise. The chart shows potential rise in kV for three tower spacings (200 m, 333 m, 500 m) at three different ground resistances (8 Ω, 25 Ω, 50 Ω). The potential rise increases with both ground resistance and tower spacing.](d68ecc44f3cfaed866a846f9fa4bdf38_img.jpg) + +| | 8 Ω | 25 Ω | 50 Ω | +|----------------|-------|-------|-------| +| Spacing: 200 m | 2.489 | 4.262 | 5.928 | +| Spacing: 333 m | 3.236 | 5.589 | 7.431 | +| Spacing: 500 m | 4.007 | 6.771 | 8.479 | + +Bar chart and data table for 1 shield-wire tower potential rise. The chart shows potential rise in kV for three tower spacings (200 m, 333 m, 500 m) at three different ground resistances (8 Ω, 25 Ω, 50 Ω). The potential rise increases with both ground resistance and tower spacing. + +a) 1 shield-wire + +![Bar chart and data table for 2 shield-wires tower potential rise. The chart shows potential rise in kV for three tower spacings (200 m, 333 m, 500 m) at three different ground resistances (8 Ω, 25 Ω, 50 Ω). The potential rise increases with both ground resistance and tower spacing.](a844248c1fa0a79f187fc9aa111182f7_img.jpg) + +| | 8 Ω | 25 Ω | 50 Ω | +|----------------|-------|--------|--------| +| Spacing: 200 m | 3.599 | 6.196 | 8.803 | +| Spacing: 333 m | 4.659 | 8.203 | 11.405 | +| Spacing: 500 m | 5.750 | 10.170 | 13.427 | + +Bar chart and data table for 2 shield-wires tower potential rise. The chart shows potential rise in kV for three tower spacings (200 m, 333 m, 500 m) at three different ground resistances (8 Ω, 25 Ω, 50 Ω). The potential rise increases with both ground resistance and tower spacing. + +b) 2 shield-wires + +![Bar chart and data table for 1 shield-wire and counterpoise tower potential rise. The chart shows potential rise in kV for three tower spacings (200 m, 333 m, 500 m) at three different ground resistances (8 Ω, 25 Ω, 50 Ω). The potential rise increases with both ground resistance and tower spacing.](5dc5581cd2aad0e683c73b959f637b31_img.jpg) + +| | 8 Ω | 25 Ω | 50 Ω | +|----------------|-------|-------|-------| +| Spacing: 200 m | 0.829 | 2.102 | 3.821 | +| Spacing: 333 m | 0.872 | 2.289 | 4.316 | +| Spacing: 500 m | 0.901 | 2.417 | 4.645 | + +Bar chart and data table for 1 shield-wire and counterpoise tower potential rise. The chart shows potential rise in kV for three tower spacings (200 m, 333 m, 500 m) at three different ground resistances (8 Ω, 25 Ω, 50 Ω). The potential rise increases with both ground resistance and tower spacing. + +K.57(16)\_Fl.11 + +c) 1 shield-wire and counterpoise + +B 400-kV line + L15 Line length: L = 15 km + F2 Fault location: L/2 km (F2) + S1 Substation earthing: 0.1 Ω/0.1 Ω + 2 × 5 kA current flow, only from the left side of the faulty point + +**Figure I.11 – Tower potential rise of the faulty tower for different tower spans** + +![3D bar chart and data table for 1 shield-wire tower potential rise. The chart shows potential rise in kV for three tower spacings (200 m, 333 m, 500 m) at three different ground resistances (8 Ω, 25 Ω, 50 Ω). The potential rise increases with both ground resistance and tower spacing.](183007754364096b2d89f42200cf870f_img.jpg) + +| | 8 Ω | 25 Ω | 50 Ω | +|----------------|-------|-------|--------| +| Spacing: 200 m | 3.596 | 6.089 | 8.367 | +| Spacing: 333 m | 4.640 | 7.858 | 10.801 | +| Spacing: 500 m | 5.679 | 9.622 | 13.227 | + +3D bar chart and data table for 1 shield-wire tower potential rise. The chart shows potential rise in kV for three tower spacings (200 m, 333 m, 500 m) at three different ground resistances (8 Ω, 25 Ω, 50 Ω). The potential rise increases with both ground resistance and tower spacing. + +a) 1 shield-wire + +![3D bar chart and data table for 2 shield-wires tower potential rise. The chart shows potential rise in kV for three tower spacings (200 m, 333 m, 500 m) at three different ground resistances (8 Ω, 25 Ω, 50 Ω). The potential rise increases with both ground resistance and tower spacing.](fae82236e4211f753df5789eb276d3a4_img.jpg) + +| | 8 Ω | 25 Ω | 50 Ω | +|----------------|-------|-------|-------| +| Spacing: 200 m | 2.479 | 4.138 | 5.638 | +| Spacing: 333 m | 3.200 | 5.342 | 7.279 | +| Spacing: 500 m | 3.916 | 6.542 | 8.916 | + +3D bar chart and data table for 2 shield-wires tower potential rise. The chart shows potential rise in kV for three tower spacings (200 m, 333 m, 500 m) at three different ground resistances (8 Ω, 25 Ω, 50 Ω). The potential rise increases with both ground resistance and tower spacing. + +b) 2 shield-wires + +![3D bar chart and data table for 1 shield-wire and counterpoise tower potential rise. The chart shows potential rise in kV for three tower spacings (200 m, 333 m, 500 m) at three different ground resistances (8 Ω, 25 Ω, 50 Ω). The potential rise increases with both ground resistance and tower spacing.](7848a2560bb726462c09c09bf727d81d_img.jpg) + +| | 8 Ω | 25 Ω | 50 Ω | +|----------------|-------|-------|-------| +| spacing: 200 m | 0.828 | 2.088 | 3.715 | +| spacing: 333 m | 0.870 | 2.259 | 4.157 | +| spacing: 500 m | 0.897 | 2.378 | 4.480 | + +3D bar chart and data table for 1 shield-wire and counterpoise tower potential rise. The chart shows potential rise in kV for three tower spacings (200 m, 333 m, 500 m) at three different ground resistances (8 Ω, 25 Ω, 50 Ω). The potential rise increases with both ground resistance and tower spacing. + +K.57(16)\_Fl.12 + +c) 1 shield-wire and counterpoise + +B 400-kV line + L60 Line length: $L = 60$ km + F2 Fault location: $L/2$ km + S1 Substation earthing: $0.1 \Omega/0.1 \Omega$ + $2 \times 5$ kA current flow, only from the left side of the faulty point + +**Figure I.12 – Tower potential rise of the faulty tower for different tower spans** + +## I.4 Estimation of the required isolation level + +The coordination of the isolation level required for the power supply circuit and the potential rise of power line towers can be made on the basis of the potential rise of the faulty tower for the deciding conditions and parameters contained in Table I.1. + +### I.4.1 Circuit representation of the faulty tower + +From the simulation of the power line – including the shield-wire system – not only the potential of the tower but also the current distribution at the faulty tower is obtained as shown in the detailed scheme of part a) of Figure I.13. These voltage and current values allow the identification of the input impedance of the shield-wire(s) seen in both directions, i.e., $Z_{sw}(l)$ and $Z_{sw}(r)$ , and their parallel equivalent, i.e., equivalent driving point impedance of the shielding-wire system seen from the faulty tower (see part b) of Figure I.13). The phasor values $Z_{sw}$ are listed in Table I.3. These are related to the one-side faulty current flow ( $1 \times 10$ kA) but identical values were obtained for the two-side ( $2 \times 5$ kA) faulty current flow in spite of the significant difference in the shield-wire current distribution. + +The driving point impedance is in the range of 0.1 to 1.2, which is quite low compared to the resistance of the tower earthing. As a conclusion, the potential rise of a given tower is determined by the average value of the earthing resistances of the neighbouring 5 to 10 towers, rather than the tower in question itself. In other words, the T-EPR of a given tower cannot be significantly reduced by the improvement of resistance of that tower only. + +**Table I.3 – Driving-point impedance seen from the faulty tower** + +| Earthing resistance [ $\Omega$ ] | Shield-wire configuration | | | | | | +|----------------------------------|---------------------------|--------|--------------|--------|--------------|--------| +| | 1 sw | | 2 sw | | 1 sw + cp | | +| | [ $\Omega$ ] | [Deg.] | [ $\Omega$ ] | [Deg.] | [ $\Omega$ ] | [Deg.] | +| 8 | 0.491 | 33.2 | 0.336 | 23.5 | 0.090 | 19.9 | +| 25 | 0.844 | 33.5 | 0.570 | 25.7 | 0.232 | 20.3 | +| 50 | 1.162 | 38.5 | 0.752 | 31.8 | 0.435 | 22.8 | + +sw shield-wire +cp counterpoise + +![Detailed scheme of a faulty tower showing phase conductors, shield-wire, and earth. Currents and impedances are labeled: 3I0(l) = 10 000 A / 180°, 3I0(r) = 0, Isw(l) = 6847 A / 1.4°, Isw(r) = 2899 A / 173°, Zsw(l), Zsw(r), UE, RE, IE = 384 A / 148°.](e451401f8fa77b466f401d5fce15b26c_img.jpg) + +Detailed scheme of a faulty tower showing phase conductors, shield-wire, and earth. Currents and impedances are labeled: 3I0(l) = 10 000 A / 180°, 3I0(r) = 0, Isw(l) = 6847 A / 1.4°, Isw(r) = 2899 A / 173°, Zsw(l), Zsw(r), UE, RE, IE = 384 A / 148°. + +a) Detailed scheme + +![Equivalent scheme of the faulty tower showing a voltage source, impedance Zsw = 0.84 Ω / 33°, current Isw = 9725 A / -1°, voltage UE = 8208 V / 32°, current IE = 384 A / 32°, and resistance RE = 25 Ω / 0°. A current source 3I0 = 10000 A / 180° is also shown.](1142ba0197b158bb198186fe8baccc32_img.jpg) + +Equivalent scheme of the faulty tower showing a voltage source, impedance Zsw = 0.84 Ω / 33°, current Isw = 9725 A / -1°, voltage UE = 8208 V / 32°, current IE = 384 A / 32°, and resistance RE = 25 Ω / 0°. A current source 3I0 = 10000 A / 180° is also shown. + +K.57(16)\_FI.13 + +b) Equivalent scheme + +- B 400-kV line with 1 shield-wire without counterpoise +- R2 Tower-earthing resistance: 25 Ω +- L15 Line length: L = 15 km +- S1 Substation earthing: 0.1 Ω/0.1 Ω +- 1 × 10 kA current flow, only from the left side of the faulty point + +**Figure I.13 – Circuit representation of the faulty tower** + +### **I.4.2 Coordination of the isolation and earth fault current levels** + +Potential rise of the faulty tower for the deciding nine conditions and parameters are given in Table I.1 for 10-kA earth fault current. The modulus of these T-EPR values are reproduced in Table I.4 and these are considered as $U_b$ base values for isolation level coordination. + +**Table I.4 – Base tower potential rise (T-EPR) values for isolation level coordination** + +| Earthing resistance [Ω] | Shield-wire configuration | | | +|-------------------------|---------------------------|-----------|----------------| +| | 1 sw [kV] | 2 sw [kV] | 1 sw + cp [kV] | +| 8 | 4.663 | 3.237 | 0.872 | +| 25 | 8.208 | 5.589 | 2.290 | +| 50 | 11.413 | 7.432 | 4.316 | +| sw shield-wire | | | | +| cp counterpoise | | | | + +By the use of $U_b$ base T-EPR values the following two kinds of design values can be determined: + +- 1) The **required isolation voltage**, $U_{is}$ for a given earth fault current can be determined by the following expression: + +$$U_{is} = U_b \frac{I_{ef}}{10} \quad [\text{kV}]$$ + +where: + +$U_b$ is the base voltage, corresponding to the average earthing resistance and shield-wire configuration of the line under study, taken from Table I.3; + +$I_{ef}$ is the earth fault current, in kA, of the power line tower containing the base station in question. + +For example, let us assume the following conditions for the power line, the tower of which contains the base station: + +- a) the power line is equipped with two shield-wires; +- b) the average value of the earthing resistance of the towers is around $25 \Omega$ ; +- c) the phase-to-earth fault current relevant to the tower holding the base station: $I_{ef} = 21 \text{ kA}$ . + +The base voltage corresponding to the first two conditions is: $U_b = 5.589 \text{ kV}$ . Considering the third condition too, the isolation voltage required for the power feeding facilities (isolating transformer, cabling) is given as: + +$$U_{is} = 5.589 \frac{21}{10} = 11.737 \quad [\text{kV}] \quad (\text{I-1})$$ + +The required isolation voltage level – as a rounded value – is 12 kV. + +- 2) The **permissible phase-to-earth fault current**, $I_{ef}$ corresponding to different pre-defined isolation voltage levels ( $U_{is}$ ) can be determined by the following expression: + +$$I_{ef} = 10 \frac{U_{is}}{U_b} \quad [\text{kA}] \quad (\text{I-2})$$ + +where: + +$U_b$ is the base voltage, corresponding to the average earthing resistance and shield-wire configuration of the line under study, taken from Table I.4; + +$U_{is}$ is the pre-defined isolation voltage levels of the power feeding facilities (isolating transformer, cabling), e.g., those listed in the first column of Table I.5. + +From an engineering design point of view, it can be assumed that a series of isolation transformers are manufactured with given isolation voltage levels. In this case, the permissible earth faults, classified according to the isolation levels, can be identified for the average earthing resistance and shield-wire configuration of the line under study by using expression I-2. + +For example, let us assume the following conditions for the power line, the tower of which contains the base station: + +- 1) the power line is equipped with two shield-wires; +- 2) the average value of the earthing resistance of the towers is around $25 \Omega$ . + +Furthermore, as a third condition: + +- 3) the isolation voltage level of the power feeding facilities (isolating transformer, cabling) $U_{is} = 20 \text{ kV}$ . + +The base voltage corresponding to the first two conditions is: $U_b = 5.589$ kV. Considering the third condition too, in the tower holding the base station is given as: + +$$I_{ef} = 10 \frac{20}{5.589} = 35.785 \quad [\text{kA}]$$ + +The rounded value of the permissible earth fault current is 36 kA according to the value given in the 8th row and 4th column of Table I.5. + +**Table I.5 – Permissible earth fault current corresponding to different isolation levels** + +| 0 | 1 | 2 | 3 | 4 | 5 | +|----|----------------------------------------------------|--------------------------------------------------------|--------------------------------------------------------------------|-----------|----------------| +| | Isolation voltage levels of the power feeding [kV] | Average earthing resistance of the towers [ $\Omega$ ] | Permissible earth fault current [kA] for shield-wire configuration | | | +| | | | 1 sw [kA] | 2 sw [kA] | 1 sw + cp [kA] | +| 1 | 10 | 8 | 21 | 31 | 115 | +| 2 | | 25 | 12 | 18 | 44 | +| 3 | | 50 | 9 | 13 | 23 | +| 4 | 15 | 8 | 32 | 46 | 172 | +| 5 | | 25 | 18 | 27 | 66 | +| 6 | | 50 | 13 | 20 | 35 | +| 7 | 20 | 8 | 43 | 62 | 229 | +| 8 | | 25 | 24 | 36 | 87 | +| 9 | | 50 | 18 | 27 | 46 | +| 10 | 50 | 8 | 107 | 154 | 573 | +| 11 | | 25 | 61 | 89 | 218 | +| 12 | | 50 | 44 | 67 | 116 | +| sw | shield-wire | | | | | +| cp | counterpoise | | | | | + +The permissible earth fault currents are determined for 10-kV, 15-kV, 20-kV and 50-kV isolation voltage levels and the above identified power line parameter options and the results are listed in rows 1 to 12 and columns 3 to 5 of Table I.5. + +The selection of the required isolation voltage level shall be made on the basis of the real earth fault current magnitudes. The magnitudes of the earth fault currents are generally available as maximum and average values for each HV level of a national grid. + +The maximum fault currents are relevant to a fault in the substation; thus, such high currents never occur in cases of power line faults. + +# Appendix II + +## Guide on the LV feeding arrangement + +(This appendix does not form an integral part of this Recommendation.) + +## II.1 LV feeding arrangement + +The low-voltage feeding is composed of the following elements (when proceeding from the tower to feeding network, see Figure 1): + +- 1) Isolating transformer, installed in the feeding cabinet, is LV/LV type, i.e., 400 V/(400/230) V, preferably delta/wye (D/Y0) connected. + +NOTE 1 – The delta connection has the advantage that there is no neutral conductor, thus no 4th MV SPD (medium voltage type surge protective device) is needed and it can feed unbalanced loads as well. + +- 2) Junction cable is the last section of the LV feeding line, entering the Z-EPR zone, between the cabinet of the isolating transformer and the junction point. Its minimum length shall be greater than the measure of the Z-EPR zone and right of way (falling distance) of the HV power line (at least 30 m). + +NOTE 2 – The junction section might be an aerial line in that exceptional case, where the national regulations allow the use of aerial lines in the right of way zone of the HV lines. + +- 3) Junction point is the connection of the junction cable and connecting LV line section. The junction shall be equipped with: + +- a low-voltage type surge protective device, LV SPD; +- low-resistance (below 10 Ω) earthing; +- power-metering facilities, if appropriate. + +- 4) The connecting line is the section of the LV feeding line between the point of coupling to the feeding network and the junction point. + +NOTE 3 – The connecting lines may feed a few customers too, especially if the lines are long (many hundreds of metres). In this case, very good earthing is required at the junction point or each customer shall be equipped with LV SPD. + +- 5) The coupling point can be at any point of a LV public network or the LV terminals of a MV/LV transformer used only for the RBS but located outside the zone of Z-EPR. The coupling shall be equipped with: + +- a SPD + +NOTE 4 – The SPD is not necessary when customers equipped with SPD are fed from the connecting line and no power-metering facilities are installed at the junction point. + +- low resistance (below 10 Ω) earthing + +NOTE 5 – In case of TN(-C-S) LV network the resultant impedance seen at the coupling point to the earth can be low enough without the application of additional earthing electrodes. + +- power-metering facilities, if appropriate + +NOTE 6 – The power metering can be made at the coupling point only in that case when no customer is fed from the connecting line. + +NOTE 7 – In case of RBS fed from MV/LV transformer located in the zone of Z-EPR and equipped with potential equalizing conductor (see Figure 5), the feeding transformer acts as an isolating transformer as well. Thus, low-voltage type SPD shall be applied in the feeding cabinet of the RBS and MOV in the MV side (this is normally applied to protect the transformer against lightning surges coming from the MV line). + +## II.2 Protection principles + +The protection of LV feeding system involves the protection against power frequency (50 Hz) overvoltages due to earth faults and the impulse stresses caused by the lightning strokes to the tower hosting the RBS. + +### II.2.1 Protection against power frequency EPR + +The earth fault current causes a power frequency (50 Hz) electrode potential rise (T-EPR) on the tower earthing itself and a progressively decreasing earth potential rise (Z-EPR) around the tower. The magnitude of the T-EPR can be estimated according to the "Guide on the coordination of the isolation level required for power supply circuit and the potential rise of power line towers" given as Appendix I. + +The principle of the protection is isolation of the LV feeding system, entering the Z-EPR, against the potential rise. The potential of the conductors of the feeding line is fixed to remote earth. (The phase conductors are earthed through the neutral earthing (assuming TN system) whilst the neutral and the cable screen, if applied, are directly earthed.) The primary winding of the isolating transformer is also on the potential of remote earth due to its metallic connection to the feeding line. On the other hand, the neutral of the secondary winding is bonded to the tower earthing. + +Under the above conditions, the protection can be provided by the appropriate: + +- 1) isolation of the primary (delta) winding of the isolating transformer with respect to the secondary winding and to the iron core and to any other metallic part of the cabinet; +- 2) isolation of the phase conductors and any metallic part (neutral screen) of the LV junction cable with respect to any earthed part of the cabinet and tower and to the earth in the Z-EPR zone; +- 3) power frequency withstand of the SPD (MOV or similar device), i.e., appropriate selection of its rated voltage ( $U_r$ ). + +NOTE – Rated voltage ( $U_r$ ) is the rms value of the power frequency voltage, which can be applied during 10 consecutive seconds between the surge arrester terminals after maximum prior duty. It characterizes the surge arrester withstand to power frequency overvoltages (temporary overvoltages). + +The continuous operating voltage ( $U_c$ ), i.e., the maximum rms value of power frequency voltage, which can be continuously applied between the arrester terminals, is 80% of $U_r$ . + +### II.2.2 Protection against lightning-generated surges + +When lightning strikes a tower hosting an RBS, the majority of the lightning current flows to the earth through the earthing of the tower. Thus a similar, but impulse type, EPR occurs as the EPR due to earth fault currents as described above. The magnitude of the impulse type tower T-EPR is essentially determined by the product of the magnitude of the lightning current and earthing impedance of the tower. Their ranges are for the lightning current 10 to 100-kA peak and for the earthing impedance 5 to 20 $\Omega$ . Therefore, the tower potential rise ranges from 50 to 2000 kV (Typical value: $50 \text{ kA} \times 10 \Omega = 500 \text{ kV peak}$ ). + +#### II.2.2.1 Protection of the isolating transformer + +The above impulse type overvoltage could occur between the windings and between the primary winding and earthed parts of the isolating transformer. It is not feasible to design the isolating transformer for such a high insulation level. For example, an isolating transformer designed for 20-kV power frequency insulation level can withstand around 70-kV impulse voltages. Therefore, the impulse overvoltage should be equalized by SPDs, connected between primary side terminals and the tower earthing to which the neutral of the secondary winding is connected as well. + +The SPD shall comply with the following requirements: + +- 1) Maximum residual voltage lower than the lightning impulse withstand of the isolating transformer. + +NOTE – The maximum residual voltage is the maximum peak value of the voltage between the surge arrester terminals at nominal discharge current. It characterizes the ability of the surge arrester to limit the overvoltage level. + +The maximum residual voltage is typically three times $U_r$ . + +- 2) Voltage ( $U_r$ ) rated high enough to ensure that the surge arrester withstands the highest power frequency tower potential rise. Considering the possible magnitude of the tower potential rise (10 to 40 kV) MV SPD surge arresters are needed for the protection of the isolating transformer (typically metal oxide varistor, MOV). + +The fulfilment of this requirement is very important to guarantee the recovery of the isolation state for power frequency subsequent to discharging the lightning impulse. + +- 3) Nominal discharge current, corresponding to the largest lightning current for which protection is intended. The current ( $I_{LV}$ ) entering the LV feeding line through the protectors is a fraction of the lightning current ( $I_L$ ) and may roughly be approximated according to the parallel connected impedance of the earthing resistance of the tower ( $R$ ) and the surge impedance of the LV line ( $Z_{LV0}$ ) as: + +$$I_{LV} = \frac{R}{R_E + Z_{LV0}} I_L \cong \frac{R}{100} I_L$$ + +In the last part of the formula it is assumed that the surge impedance of the cable-like LV feeder ranges from 80 to 90 $\Omega$ ; thus, $Z_{LV0} + R \cong 100 \Omega$ . + +#### II.2.2.2 Protection of the junction cable + +The MV SPDs connected to the primary side terminals of the isolating transformer inject lightning impulse into the junction cable. The magnitude of the injected surge voltage with respect to the tower and also to the earth in the vicinity of the tower is equal to the residual voltage of the MV SPDs. Consequently the voltage stress across the cable, i.e., phase conductors to earth in case of unscreened cable or screen to earth in case of screened cable, is equal to the residual voltage of the MV SPDs in the vicinity of the tower. + +The identification of the voltage stress of the junction cable is more difficult farther away from the tower. The magnitude of the injected surge voltage with respect to remote earth is the lightning impulse potential of the tower diminished by the residual voltage through the MV SPDs. This represents a surge having a few hundreds kV peak. However, the peak value of the impulse wave would appear in the cable only in the case when the wave could travel such a distance, that the peak of the wave would be at a point in the LV feeding cable, which is out of the EPR zone. The geometrical extension along the LV line of the front of the wave is about 300 m, even assuming a very steep wave with front time of 1 $\mu\text{s}$ . The junction cable is typically 50-150 m in length (see Appendix III). Its conductors are terminated to the earth by either LV SPDs (phase conductors) or are directly earthed (neutral conductor and screen if applied), which practically provides a short circuit at the junction point. This short-circuit-type termination causes negative reflected voltage wave, which tends to diminish the incoming wave. The resulted voltage remains below about 1/10th of the peak as far as the junction cable remains short. + +With the above conditions it can be assumed that the voltage stress of the LV cable is not higher even to the remote earth, i.e., outside the EPR zone, than the residual voltage of the MV SPDs protecting the isolating transformers. However, the high insulation level should be maintained along the whole length of the junction cable. + +Finally, it should be noted that the explanations above are of a qualitative kind, neglecting the effects of a couple of factors, i.e., the potential rise at the earthing of the junction point, and the effect of the connecting feeding line section. Precise design values for actual conditions can be obtained from quantitative analyses, e.g., by ElectroMagnetic Transient Program (EMTP) simulation. + +## II.3 Selection of the design values for the protection + +The design values for the characterization of the protection elements can be identified in the following way and logical order. + +### II.3.1 Voltage level of the isolating transformer + +- a) The insulation voltage level at 50 Hz of the primary winding of the isolating transformer shall be higher than the maximum rms value of the tower potential rise due to earth fault. It is essentially determined by the magnitude of the earth fault current, the average value of earthing resistances of the towers, the shield-wires and counterpoise. For the selection of the required isolation level, guidance is given in Appendix I. +- b) However, the following power frequency voltage levels of isolation between the windings and between the primary winding and earthed parts are relevant for the most practical applications: + - 10 kV rms, for the most practical cases up to 20-kA earth fault current; + - 20 kV rms, when the average value of the earthing resistances are high and for severe earth fault current, i.e., up to 40 kA. +- c) In addition, the impulse voltage dielectric strength of the primary winding shall be higher than the residual voltage of the applied MV SPDs (MOV or similar). Informative values for characteristics of typical MV SPD are given for the above isolation levels in Table II.1. + +### II.3.2 MV SPD (MOV or similar) characteristics + +- a) Rated voltage ( $U_r$ ) of the MV SPD shall be equal to or higher than the maximum rms value of the ERP of the tower concerned, due to earth fault. + +**Table II.1 – The characteristics of MV SPD (MOV or similar) corresponding to two typical voltage levels of the isolation transformer** + +| Isolation level
of the transformer
[kV rms] | MV SPD (MOV) arrester characteristics | | | | +|---------------------------------------------------|---------------------------------------|-------------------------------------------------------|--------------------------------------------|-----------------------| +| | Rated voltage,
$U_r$
[kV rms] | Continuous
operating voltage,
$U_c$
[kV rms] | Residual voltage
with 8/20 $\mu$ s wave | | +| | | | at 10 kA
[kV peak] | at 20 kA
[kV peak] | +| 10 | 10 | 8 | 28 | 32 | +| 20 | 20 | 16 | 56 | 64 | + +- b) Nominal discharge current shall correspond to the highest lightning current, which should be diverted by the arrester. + +NOTE – The nominal discharge current is the peak value of the lightning current impulse having a 8/20 bi-exponential impulse wave shape, which is used to classify surge arresters. The energy absorption capacity, given in kJ/kV $U_c$ , is also used to characterize the discharge capability of the protector. + +The diverted current is a fraction of the lightning current. Its value, in per cent, is roughly equal to the earthing resistance, in ohms, of the tower, where the RBS is installed (see clause II.2.2.1)). + +A MOV with nominal discharge current of 20 kA can provide protection from a lightning current of at least 100-kA peak, when the earthing resistance is below 20 $\Omega$ . In case of lower earthing resistance, MOVs with nominal discharge current lower than 20 kA can provide appropriate protection. + +### II.3.3 LV SPD characteristics + +The nominal discharge current of the LV SPDs shall be equal to or higher than that of the MV SPDs in case of LV SPDs connected between each phase conductor and earth at the junction point according to clause II.3.2 b). + +NOTE – Considering clause II.3.2 b), the applied LV SPD shall have at least the nominal discharge current of 20 kA. + +In other cases the selection and application of LV SPDs shall comply with the requirements specified in the IEC standard series of IEC 61643 especially [IEC 61643-11] and [IEC 61643-12]. + +### II.3.4 Junction cable + +#### II.3.4.1 Isolation withstand voltage + +The isolation withstand voltage of the junction cable to earth shall be higher than the rated voltage and the residual voltage of the applied MV SPD (MOV) for power frequency and surge voltage (see the informative values given in Table II.2). + +These withstand voltages shall be ensured between the metallic structures and earth between which the MV SPD are applied, i.e., between the phase conductors and earth in case of Option 1, whilst between the screen and the earth in cases of Options 2 and 3. + +NOTE – The required voltages withstand between the isolated fittings and earthed parts of the feeding cabinet can be ensured by sufficient clearance distances. The minimum clearances for the maximum apparatus voltages and the respective insulation levels according to [b-IEC 71] are as follows: + +**Table II.2 – Informative values for the required voltage withstand and clearances** + +| Maximum voltage for apparatus [kV rms] | Rated lightning impulse withstand voltage [kV peak] | Minimum clearance (indoors) [mm] | +|----------------------------------------|-----------------------------------------------------|----------------------------------| +| 12 | 75 | 90 | +| 24 | 125 | 160 | + +#### II.3.4.2 Length of the junction cable + +The minimum length of the junction cable shall be greater than the measure of the EPR zone and right of way (falling distance), where applicable, of the HV power line (at least 30 m; for more details, see Appendix III). + +On the other hand, unnecessary extension of the junction cable should be avoided as far as possible, to reduce the cost of this section having increased isolation level and to prevent the occurrence of overvoltage due to the travelling wave phenomenon (see clause II.2.2.2 and also Appendix III). + +## II.4 Options for the feeding of multiple RBSs + +In some cases more than one RBS – e.g., operated by different service providers – may be mounted in the same power line tower. The possible feeding options of this multiple RBS operation are demonstrated in Figure II.1 with the assumption of two RBSs. More and more elements of the feeding system become commonly used, when proceeding from options a) to c) thus resulting in the less installation cost, but on the other hand less flexibility in the operation and maintenance. + +The different feeding arrangements (see Figure II.1) can be characterized by the following main features: + +- a) Each circuit element is separated, i.e., duplicated from the junction point to the feeding cabinet. A separate consumption (kWh) meter for each RBS can be installed either at the junction point or at the separate compartment of the feeding cabinet. It is worth mentioning that the LV SPDs could, in principle, be combined and replaced by a single set connected to the common (feeding line) branch. +- b) The junction cable, the MV SPD and LV SPD at the feeding cabinet and the junction point respectively are common for the two RBSs. Separate consumption meters for each RBS can only be installed at the separate compartments of the feeding cabinet. +- c) The junction cable, the SPDs and the isolating transformer are used commonly. The feeding is separated only on the secondary side of the isolating transformer. The consumption of each RBS can be measured by subsidiary meters installed in separate compartments on the feeding cables at the secondary side. A meter for common consumption – including the loss of the isolating transformer – can be installed either in the primary side compartment of the feeding cabinet or at the junction point. + +![Three electrical diagrams (a, b, c) showing different feeding options for multiple RBSs in a tower. Diagram (a) shows separate feeding with individual junction cables and SPDs. Diagram (b) shows a common junction cable and SPDs (both MV and LV types). Diagram (c) shows a common junction cable, SPDs, and an isolating transformer. Each diagram includes a junction box, feeding line, RBS 1, RBS 2, and tower earthing.](e8e818455bb0d1a6153299a388b94868_img.jpg) + +**a) Separate feeding** + +The diagram shows a 'Junction box' on the left containing a 'Feeding line' with a neutral (N) point, two 'LV SPD' units, and a 'Junction point earthing'. Two 'Junction cables' lead from this box to a 'Feeding cabinet' on the right. The 'Feeding cabinet' contains two 'RBS' units (RBS 1 and RBS 2), each with its own 'MV SPD' unit connected to 'Tower earthing'. + +**b) Common junction cable and SPDs (both MV and LV types)** + +The diagram shows a 'Junction box' on the left containing a 'Feeding line' with a neutral (N) point, an 'LV SPD' unit, and a 'Junction point earthing'. A 'Common junction cable' leads from this box to a 'Feeding cabinet' on the right. The 'Feeding cabinet' contains two 'RBS' units (RBS 1 and RBS 2) and a single 'MV SPD' unit connected to 'Tower earthing'. + +**c) Common junction cable, SPDs and isolating transformer** + +The diagram shows a 'Junction box' on the left containing a 'Feeding line' with a neutral (N) point, an 'LV SPD' unit, and a 'Junction point earthing'. A 'Common junction cable' leads from this box to a 'Feeding cabinet' on the right. The 'Feeding cabinet' contains an isolating transformer, two 'RBS' units (RBS 1 and RBS 2), and an 'MV SPD' unit connected to 'Tower earthing'. The label 'K.57(16)\_FII.1' is present at the bottom right of the diagram. + +Three electrical diagrams (a, b, c) showing different feeding options for multiple RBSs in a tower. Diagram (a) shows separate feeding with individual junction cables and SPDs. Diagram (b) shows a common junction cable and SPDs (both MV and LV types). Diagram (c) shows a common junction cable, SPDs, and an isolating transformer. Each diagram includes a junction box, feeding line, RBS 1, RBS 2, and tower earthing. + +**Figure II.1 – Options for the feeding of multiple RBSs mounted in the same tower** + +# Appendix III + +## Characterization and control of the EPR zone of tower earthing and estimation of the minimum length of the junction section + +(This appendix does not form an integral part of this Recommendation.) + +## III.1 Characterization of the zone of EPR of the tower earthing + +### III.1.1 EPR for actual tower footings + +This clause describes characteristics of the zone of the earth potential rise (Z-EPR) occurring around the tower footing due to the current injected to the earth through the earthing electrode system of a high-voltage power line tower. It also presents a collection of figures obtained on the one hand from field measurements and on the other hand by simulation studies. + +The profile curves of Z-EPR vs. distance in per cent, normalized to the earthing potential ( $V_e$ ), are given in Figure III.1. These profiles were obtained from measurements made in the field around the footing of a 220-kV power line, the measures of which are given in part b) of Figure III.1. Part a) of the referred figure shows measured Z-EPR profiles vs. distance at the surface of the earth in the specified four directions [b- Favez]. + +Part b) of Figure III.1 shows the normalized potential profiles with log-log scaling, thus providing better comparison between the profiles of different directions indicated in the figure for further distances. + +3D plots of Z-EPR are given in Figure III.2 in two different scalings. These were obtained from simulation [b-Cdegs] of the earthing system of a 220-kV line, the structure of which is given in Figure III.3. + +Profiles of Z-EPR normalized to the tower potential, at a depth of 0.5 m, perpendicular to the route of the line, through the centre point between the legs of the tower, are plotted for two different earth resistivities in Figure III.4. This is a case where no ring conductor is installed. + +On the base of the information provided, the following main conclusions can be made for practical purposes: + +- In the close vicinity of the tower footing, the change in the EPR is quite rapid. Therefore, the bonding for potential equalization of the different cabinets, e.g., feeding and RBS equipment, is of essential importance. +- The specific resistivity of the earth affects the magnitude of the earthing potential, T-EPR and Z-EPR, but does not affect the magnitude and the profile of the normalized Z-EPR (see Figure III.4). +- The differences of the Z-EPR profiles in different directions are only significant in the close vicinity of the tower footing. At further distances from the tower footing, the Z-EPR profiles in different directions are practically identical and decrease with the distance $x$ according to $1/x$ (hyperbolic) pattern. The later statement allows for the equivalent hemispheric representation of the tower earthing for practical purposes. + +### III.1.2 Representation of the Z-EPR by equivalent hemisphere concept + +It is well known from the technical literature [b-ITU-T Handbook] that the Z-EPR can be described with very simple expressions, when a hemisphere or an equivalent hemisphere replaces the actual electrode. + +These simple formulae also assume homogeneous soil at least in the surface layer. + +The Z-EPR of a hemispheric electrode at a distance $x$ is given by: + +$$V_x = \frac{\rho}{2\pi x} I \quad (\text{III-1})$$ + +where: + +$\rho$ is the resistivity of the soil; and + +$I$ is the current flowing through the earthing electrode + +The earthing potential $V_e$ of the tower becomes: + +$$V_e = R \cdot I \quad (\text{III-2})$$ + +where $R$ is the earthing resistance of the power tower. + +Making the ratio of $V_x/V_e$ the following expression is obtained: + +$$\frac{V_x}{V_e} = \frac{\rho}{2\pi R x} \frac{1}{I} \quad (\text{III-3})$$ + +Finally, the minimum distance $x_{\min}$ from the centre of the electrode, where the earth potential $V_x$ is equal to a stipulated value can be obtained as: + +$$x_{\min} = \frac{1}{2\pi} \frac{\rho}{R} \frac{V_e}{V_x} \quad (\text{III-4})$$ + +where the following values are assumed to be known: + +$\rho$ the specific resistivity of the surface soil at the location of the tower holding the RBS + +$R$ earthing resistance of the tower holding the RBS (the value considered in Appendix I) + +$V_e$ potential rise of the tower holding the RBS (the value obtained according to Appendix I) + +$V_x$ admissible no load earth potential at the remote end of the junction section, i.e., at the junction point. + +When the junction cable is laid along a straight route, then $x_{\min}$ is equal to the required minimum length of the junction section. + +![Graph showing normalized potential profiles (100 * Vx / Ve [%]) versus distance X [m] for four directions (n° 1, 2, 3, 4) near the tower footing. The y-axis is linear from 0 to 100. The x-axis is logarithmic from 1 to 150. Curves for directions 1, 2, 3, and 4 are shown, peaking at 100% at X=5m. A theoretical curve Vx/Ve = s/x is also shown.](76959415a1298a6f58ea1fff16fb01b6_img.jpg) + +Graph showing normalized potential profiles ( $100 \frac{V_x}{V_e} [\%]$ ) versus distance $X$ [m] for four directions (n° 1, 2, 3, 4) near the tower footing. The y-axis ranges from 0 to 100, and the x-axis ranges from 1 to 150 m. The curves show a sharp peak at $X \approx 5$ m and then decay. A formula $\frac{V_x}{V_e} = \frac{s}{x}$ is indicated. + +Graph showing normalized potential profiles (100 \* Vx / Ve [%]) versus distance X [m] for four directions (n° 1, 2, 3, 4) near the tower footing. The y-axis is linear from 0 to 100. The x-axis is logarithmic from 1 to 150. Curves for directions 1, 2, 3, and 4 are shown, peaking at 100% at X=5m. A theoretical curve Vx/Ve = s/x is also shown. + +a) Normalized potential profiles near the tower footing in different directions indicated in the figure (the label *s* is the radius of the equivalent hemisphere representing the tower earthing) + +![Graph showing normalized potential profiles (100 * Vx / Ve [%]) versus distance X [m] on a log-log scale for three directions (R1, R2, R3) from the tower footing. The y-axis ranges from 3 to 100, and the x-axis ranges from 3 to 500 m. An inset diagram shows the tower footing dimensions: 6.25 m by 4.70 m, with a 1.5 m offset from the center.](9857175bc98d86591d24a161fe615f12_img.jpg) + +Graph showing normalized potential profiles ( $100 \frac{V_x}{V_e} [\%]$ ) versus distance $X$ [m] on a log-log scale for three directions (R1, R2, R3) from the tower footing. The y-axis ranges from 3 to 100, and the x-axis ranges from 3 to 500 m. The curves show a linear decay on the log-log scale. An inset diagram shows the tower footing dimensions: 6.25 m by 4.70 m, with a 1.5 m offset from the center. + +Graph showing normalized potential profiles (100 \* Vx / Ve [%]) versus distance X [m] on a log-log scale for three directions (R1, R2, R3) from the tower footing. The y-axis ranges from 3 to 100, and the x-axis ranges from 3 to 500 m. An inset diagram shows the tower footing dimensions: 6.25 m by 4.70 m, with a 1.5 m offset from the center. + +b) Normalized potential profiles with log-log scaling for further distances from tower footing to different directions indicated in the figure + +K.57(16)\_FIII.1 + +**Figure III.1 – Z-EPR normalized by the earthing potential (in per cent) measured around the footing of a 220-kV power line with the measures given in Figure III.1 b)** + +![3D surface plot (a) showing Potential profile magnitude (volts) vs Distance from origin of profile (m) for a 40 x 40 m area. The vertical axis ranges from 0 to 6000 volts. The horizontal axes range from -20 to +40 m. The plot shows a series of peaks and valleys centered around the origin, with the highest peaks reaching approximately 6000 volts.](657acccf744d33f1fc3a1652741a256e_img.jpg) + +Potential profile magnitude (volts) + +6000 + +4500 + +3000 + +1500 + +0 + ++40 + ++24 + ++16 + ++8 + +-16 + +-24 + +Distance (m) + +-20 0 +20 + +Distance from origin of profile (m) + +3D surface plot (a) showing Potential profile magnitude (volts) vs Distance from origin of profile (m) for a 40 x 40 m area. The vertical axis ranges from 0 to 6000 volts. The horizontal axes range from -20 to +40 m. The plot shows a series of peaks and valleys centered around the origin, with the highest peaks reaching approximately 6000 volts. + +a) Shown area: 40 × 40 m + +![3D surface plot (b) showing Potential profile magnitude (volts) vs Distance from origin of profile (m) for a 100 x 100 m area. The vertical axis ranges from 0 to 6000 volts. The horizontal axes range from -50 to +50 m. The plot shows a series of peaks and valleys centered around the origin, with the highest peaks reaching approximately 6000 volts. A label 'K.57(16)_FIII.2' is present in the bottom right corner.](bdd910852600bb450eb8544a4c88b280_img.jpg) + +Potential profile magnitude (volts) + +6000 + +4500 + +3000 + +1500 + +0 + ++50 + +0 + +Distance (m) + +-50 0 +50 + +Distance from origin of profile (m) + +K.57(16)\_FIII.2 + +3D surface plot (b) showing Potential profile magnitude (volts) vs Distance from origin of profile (m) for a 100 x 100 m area. The vertical axis ranges from 0 to 6000 volts. The horizontal axes range from -50 to +50 m. The plot shows a series of peaks and valleys centered around the origin, with the highest peaks reaching approximately 6000 volts. A label 'K.57(16)\_FIII.2' is present in the bottom right corner. + +b) Shown area: 100 × 100 m + +**Figure III.2 – 3D plots of Z-EPR at a depth of 0.5 m, $\rho = 1500 \ \Omega\text{m}$ , earth fault current: 10 kA, number of earth wire: 1, earthing structure according to Figure III.3** + +![Diagram of earthing electrode arrangement. Four 800x800 mm square electrodes are placed at the corners of a square with center-to-center side lengths of 6212 mm. A central label indicates Ø 30. Reference: K.57(16)_FIII.3.](5ee1bbbf85b473f78af9ec8368a4159a_img.jpg) + +``` + +graph TD + A[Electrode 1] ---|6212 mm| B[Electrode 2] + A ---|6212 mm| C[Electrode 3] + B ---|6212 mm| D[Electrode 4] + C ---|6212 mm| D + subgraph Electrode_Size + 800mm_x_800mm + end + +``` + +Diagram of earthing electrode arrangement. Four 800x800 mm square electrodes are placed at the corners of a square with center-to-center side lengths of 6212 mm. A central label indicates Ø 30. Reference: K.57(16)\_FIII.3. + +**Figure III.3 – Arrangement and sizes (in mm) of earthing electrodes of a 220-kV +power line considered in the EPR simulation – Depth of electrodes: 1.7 m** + +![Graph of normalized Z-EPR profiles at 0.5 m depth. The y-axis is normalized potential (0.00 to 0.50). The x-axis is distance from center (-50 to 50 m). Two curves are shown for ρ = 50 Ωm and ρ = 1500 Ωm. Reference: K.57(16)_FIII.4.](7e2465b81aed11b2e58575a811424b75_img.jpg) + +| Distance (m) | Normalized Z-EPR (ρ = 50 Ωm) | Normalized Z-EPR (ρ = 1500 Ωm) | +|--------------|------------------------------|--------------------------------| +| -50 | 0.04 | 0.05 | +| -25 | 0.10 | 0.12 | +| 0 | 0.45 | 0.45 | +| 25 | 0.10 | 0.12 | +| 50 | 0.04 | 0.05 | + +Graph of normalized Z-EPR profiles at 0.5 m depth. The y-axis is normalized potential (0.00 to 0.50). The x-axis is distance from center (-50 to 50 m). Two curves are shown for ρ = 50 Ωm and ρ = 1500 Ωm. Reference: K.57(16)\_FIII.4. + +**Figure III.4 – Profiles of Z-EPR normalized by the tower potential, at a depth of 0.5 m, +perpendicular to the route of line through the centre point between the legs of the tower** + +## III.2 Control of touch and step voltages by potential PGE + +The investigation of the Z-EPR has shown significant difference in the potential between the legs of the tower and also beside the tower (see Figures III.1, III.2 and III.4). This difference causes touch and step voltages which can affect the staff working in the vicinity of the cabinet of RBS. The possible control of touch and step voltages by PGE is investigated below. + +### III.2.1 Effectiveness of the PGE + +#### a) *Applied simulation technique and basic parameters* + +The simulation calculations have been made by the CDEGS software package (see [b-Cdegs]). This technique allows the consideration of the actual earthing electrode arrangement and the soil resistivity and structure (even stratified earth). + +In the calculations, the following general conditions were considered: + +- homogenous earth (specific resistivity of $\rho = 50 \text{ } \Omega\text{m}$ ); +- frequency: 50 Hz (current injection: 1000 A to the tower, including the legs). + +It is worth mentioning that only normalized values are considered in the evaluations, which are affected neither by the specific resistivity of the earth nor by the magnitude of the injected current. + +#### b) *Arrangement of the tower earth and the potential grading earth electrodes simulation* + +The earthing electrode arrangement of the tower is the one specified in Table III.1 under case code 9. The sizes are reproduced in Figure III.7. In fact, the tower earth system is composed of four square-form electrodes placed at the bottom of the tower foundation and bonded together through the tower body (see Figure III.14). The structure and the sizes of the tower earth are characterized by: + +- electrode material: steel, circular with a diameter of 30 mm; +- depth: 2.0 m; +- lateral size of the square-form electrode of each leg: $1.7 \times 1.7$ m; +- spacing between the centre line of the tower leg electrodes: $6.5 \times 6.5$ m. + +The electrode arrangements and grading earth electrode frames are shown for the cabinet beside the tower in Figure III.5, and for the cabinet between the legs of the tower in Figure III.6. + +The structure and arrangement of the simulated voltage grading earth frame electrode systems are as follows: + +- electrode material: steel, circular with a diameter of 20 mm; +- depth: 0.3 m; +- positions: + - beside the tower (see Figure III.5); + - between the tower legs centrally located (see Figure III.6); +- sizes of the PGE (see Figure III.7): + - outer frame $3.6 \times 3.6$ m; + - inner frame $2.4 \times 2.4$ m. + +The sizes of the PGE frames are identical for the cabinet beside the tower and between the legs of the tower. If only a single frame is assumed, it is the outer one. + +![Figure III.5: Arrangement of the tower-earthing electrodes and potential grading double frame earth electrodes. Cabinet location: beside the tower. The diagram shows a 3D perspective view of a tower structure with four legs. Each leg has a square-form electrode at its base, indicated by a depth of -2.0 m. A potential grading (PGE) system is shown as two concentric rectangular frames around the tower base, with a depth of -0.3 m. The distance between the center lines of the tower leg electrodes is labeled as 15 m. A coordinate system (X, Y, Z) is shown, with the Z-axis being vertical and the X and Y axes being horizontal. The label K.57(16)_FIII.5 is present at the bottom right of the diagram.](3bb9d77aa26ab3da0a63d88e18678b77_img.jpg) + +Figure III.5: Arrangement of the tower-earthing electrodes and potential grading double frame earth electrodes. Cabinet location: beside the tower. The diagram shows a 3D perspective view of a tower structure with four legs. Each leg has a square-form electrode at its base, indicated by a depth of -2.0 m. A potential grading (PGE) system is shown as two concentric rectangular frames around the tower base, with a depth of -0.3 m. The distance between the center lines of the tower leg electrodes is labeled as 15 m. A coordinate system (X, Y, Z) is shown, with the Z-axis being vertical and the X and Y axes being horizontal. The label K.57(16)\_FIII.5 is present at the bottom right of the diagram. + +**Figure III.5 – Arrangement of the tower-earthing electrodes and potential grading double frame earth electrodes. Cabinet location: beside the tower** + +![Figure III.6: Arrangement of the tower-earthing electrodes and potential grading double frame earth electrodes. The diagram shows a top-down view of a tower structure with four legs. A dashed vertical line labeled 'Y' and a dashed horizontal line labeled 'X' intersect at the center. Two rectangular electrodes are shown, one on each side of the center, oriented parallel to the X-axis. The distance from the center line to the inner edge of each electrode is labeled -0.3 m. The distance from the center line to the outer edge of each electrode is labeled -2.0 m. The label K.57(16)_FIII.6 is at the bottom right.](2580688a4de0a29692805cc6ba4822d7_img.jpg) + +Figure III.6: Arrangement of the tower-earthing electrodes and potential grading double frame earth electrodes. The diagram shows a top-down view of a tower structure with four legs. A dashed vertical line labeled 'Y' and a dashed horizontal line labeled 'X' intersect at the center. Two rectangular electrodes are shown, one on each side of the center, oriented parallel to the X-axis. The distance from the center line to the inner edge of each electrode is labeled -0.3 m. The distance from the center line to the outer edge of each electrode is labeled -2.0 m. The label K.57(16)\_FIII.6 is at the bottom right. + +**Figure III.6 – Arrangement of the tower-earthing electrodes and potential grading double frame earth electrodes. Cabinet location: between the tower legs** + +![Figure III.7: Sizes of the tower-earthing electrode and PGE double frame electrode, in m. The diagram shows a top-down view of a tower structure with four legs. A dashed vertical line labeled 'Y' and a dashed horizontal line labeled 'X' intersect at the center. The tower legs are represented by lines converging towards the center. The distance from the center line to the inner edge of the tower legs is labeled 6.5. The distance from the center line to the outer edge of the tower legs is labeled 15. The distance from the center line to the inner edge of the electrodes is labeled 6.5. The distance from the center line to the outer edge of the electrodes is labeled 15. The electrodes are rectangular, with a width of 1.7 m and a length of 1.7 m. The distance from the center line to the inner edge of the electrodes is labeled 2.4. The distance from the center line to the outer edge of the electrodes is labeled 3.6. The label K.57(16)_FIII.7 is at the bottom right.](40ebe9179df298f1b6d76822f28d90aa_img.jpg) + +Figure III.7: Sizes of the tower-earthing electrode and PGE double frame electrode, in m. The diagram shows a top-down view of a tower structure with four legs. A dashed vertical line labeled 'Y' and a dashed horizontal line labeled 'X' intersect at the center. The tower legs are represented by lines converging towards the center. The distance from the center line to the inner edge of the tower legs is labeled 6.5. The distance from the center line to the outer edge of the tower legs is labeled 15. The distance from the center line to the inner edge of the electrodes is labeled 6.5. The distance from the center line to the outer edge of the electrodes is labeled 15. The electrodes are rectangular, with a width of 1.7 m and a length of 1.7 m. The distance from the center line to the inner edge of the electrodes is labeled 2.4. The distance from the center line to the outer edge of the electrodes is labeled 3.6. The label K.57(16)\_FIII.7 is at the bottom right. + +**Figure III.7 – Sizes of the tower-earthing electrode and PGE double frame electrode, in m** + +#### c) *Surface potential and touch voltage profiles* + +The Cdegs code provides a complete EMF solution of the electrode system providing, e.g., the potential, current distribution, electric and magnetic field in any place of the surrounding area. This result can be further processed, thus resulting in the touch and step voltages, etc. + +A general overview is provided by the 3D plot of the potential at a given level of the earth, as shown in Figure III.2. + +For the quantitative analysis of the results, the profiles of the earth surface potential to remote earth and the touch voltage between the cabinet earthing (bonded with the tower earthing) and the earth surface near the cabinet are given vs. length in three representative directions for the following two cabinet locations: + +- beside the tower (see Figures III.8, III.9 and III.10); + +- between the tower legs (see Figures III.11, III.12 and III.13). + +![Figure III.8: Profile of touch voltage (pu) for cabinet beside the tower. Profile: X direction, in centre line of the grading electrode frame. The graph shows touch voltage (pu) on the y-axis (0.0 to 1.0) versus distance (m) on the x-axis (-5 to 5). Three curves are shown: 'No frame' (dashed line), 'Single frame' (solid line), and 'Double frame' (solid line). The 'No frame' curve is relatively flat around 0.8 pu. The 'Single frame' and 'Double frame' curves show a significant dip in touch voltage near the center (0 m), with the 'Double frame' curve reaching a minimum of approximately 0.1 pu. The 'Grading frame' is indicated by a label pointing to the center area. The graph is labeled K.57(16)_FIII.8.](892c6816711b2d83080366cf799d2c62_img.jpg) + +Figure III.8: Profile of touch voltage (pu) for cabinet beside the tower. Profile: X direction, in centre line of the grading electrode frame. The graph shows touch voltage (pu) on the y-axis (0.0 to 1.0) versus distance (m) on the x-axis (-5 to 5). Three curves are shown: 'No frame' (dashed line), 'Single frame' (solid line), and 'Double frame' (solid line). The 'No frame' curve is relatively flat around 0.8 pu. The 'Single frame' and 'Double frame' curves show a significant dip in touch voltage near the center (0 m), with the 'Double frame' curve reaching a minimum of approximately 0.1 pu. The 'Grading frame' is indicated by a label pointing to the center area. The graph is labeled K.57(16)\_FIII.8. + +**Figure III.8 – Profile of touch voltage (pu, Base: T-EPR) for cabinet beside the tower. +Profile: X direction, in centre line of the grading electrode frame** + +![Figure III.9: Profile of touch voltage (pu) for cabinet beside the tower. Profile: Y direction, in centre line of the grading frame and tower-earthing electrodes. The graph shows touch voltage (pu) on the y-axis (0.0 to 1.0) versus distance (m) on the x-axis (-20 to 10). Four curves are shown: 'No frame' (dashed line), 'Single frame' (solid line), 'Double frame' (solid line), and 'Grading frame' (solid line). The 'No frame' curve shows a gradual decrease from about 0.8 pu at -20 m to 0.4 pu at 0 m. The 'Single frame', 'Double frame', and 'Grading frame' curves show a sharp dip in touch voltage between -15 m and -10 m, with the 'Grading frame' curve reaching a minimum of approximately 0.1 pu. The 'Tower frame' is indicated by a label pointing to the right side of the graph. The graph is labeled K.57(16)_FIII.9.](6752cee124f693bc4cebc66180f4f91f_img.jpg) + +Figure III.9: Profile of touch voltage (pu) for cabinet beside the tower. Profile: Y direction, in centre line of the grading frame and tower-earthing electrodes. The graph shows touch voltage (pu) on the y-axis (0.0 to 1.0) versus distance (m) on the x-axis (-20 to 10). Four curves are shown: 'No frame' (dashed line), 'Single frame' (solid line), 'Double frame' (solid line), and 'Grading frame' (solid line). The 'No frame' curve shows a gradual decrease from about 0.8 pu at -20 m to 0.4 pu at 0 m. The 'Single frame', 'Double frame', and 'Grading frame' curves show a sharp dip in touch voltage between -15 m and -10 m, with the 'Grading frame' curve reaching a minimum of approximately 0.1 pu. The 'Tower frame' is indicated by a label pointing to the right side of the graph. The graph is labeled K.57(16)\_FIII.9. + +**Figure III.9 – Profile of touch voltage (pu, Base: T-EPR) for cabinet beside the tower. +Profile: Y direction, in centre line of the grading frame and tower-earthing electrodes** + +![Figure III.10: Profile of touch voltage (pu, Base: T-EPR) for cabinet beside the tower. The graph shows touch voltage (pu) on the y-axis (0.0 to 1.0) versus distance (m) on the x-axis (-5 to 5). Four curves are shown: 'No frame' (dashed black line, highest), 'Single frame' (dashed blue line), 'Grading frame' (solid red line), and 'Double frame' (solid red line, lowest). Markers on the x-axis indicate the locations of the tower legs and the cabinet.](a8523d225a4e279ab9e02f3c28cfa36a_img.jpg) + +Figure III.10 is a line graph showing the profile of touch voltage (pu) for a cabinet beside the tower. The y-axis represents touch voltage in per unit (pu) from 0.0 to 1.0. The x-axis represents distance in meters (m) from -5 to 5. The graph includes four curves: 'No frame' (dashed black line), 'Single frame' (dashed blue line), 'Grading frame' (solid red line), and 'Double frame' (solid red line). The 'No frame' curve is the highest, starting around 0.8 pu at -5 m and slightly decreasing. The 'Single frame' curve is lower, peaking around 0.25 pu at 0 m. The 'Grading frame' and 'Double frame' curves are the lowest, peaking around 0.1 pu at 0 m. Markers on the x-axis indicate the locations of the tower legs (at approximately -2.5 m and 2.5 m) and the cabinet (at approximately -1.5 m and 1.5 m). + +Figure III.10: Profile of touch voltage (pu, Base: T-EPR) for cabinet beside the tower. The graph shows touch voltage (pu) on the y-axis (0.0 to 1.0) versus distance (m) on the x-axis (-5 to 5). Four curves are shown: 'No frame' (dashed black line, highest), 'Single frame' (dashed blue line), 'Grading frame' (solid red line), and 'Double frame' (solid red line, lowest). Markers on the x-axis indicate the locations of the tower legs and the cabinet. + +**Figure III.10 – Profile of touch voltage (pu, Base: T-EPR) for cabinet beside the tower. +Profile: direction 45° through the centre point of the PGE frame** + +![Figure III.11: Profile of touch voltage (pu, Base: T-EPR) for cabinet between the tower legs. The graph shows touch voltage (pu) on the y-axis (0.0 to 0.5) versus distance (m) on the x-axis (-5 to 5). Five curves are shown: 'No frame' (dashed black line, highest), 'Single frame' (dashed blue line), 'Grading frame' (solid red line), 'Double frame' (solid red line), and 'Tower earthing' (solid red line, lowest). Markers on the x-axis indicate the locations of the tower legs and the cabinet.](fe6af03ab7804980cff28a06241be192_img.jpg) + +Figure III.11 is a line graph showing the profile of touch voltage (pu) for a cabinet between the tower legs. The y-axis represents touch voltage in per unit (pu) from 0.0 to 0.5. The x-axis represents distance in meters (m) from -5 to 5. The graph includes five curves: 'No frame' (dashed black line), 'Single frame' (dashed blue line), 'Grading frame' (solid red line), 'Double frame' (solid red line), and 'Tower earthing' (solid red line). The 'No frame' curve is the highest, starting around 0.35 pu at -5 m and slightly increasing. The 'Single frame' curve is lower, peaking around 0.25 pu at 0 m. The 'Grading frame' and 'Double frame' curves are the lowest, peaking around 0.1 pu at 0 m. The 'Tower earthing' curve is the lowest of all, peaking around 0.05 pu at 0 m. Markers on the x-axis indicate the locations of the tower legs (at approximately -2.5 m and 2.5 m) and the cabinet (at approximately -1.5 m and 1.5 m). + +Figure III.11: Profile of touch voltage (pu, Base: T-EPR) for cabinet between the tower legs. The graph shows touch voltage (pu) on the y-axis (0.0 to 0.5) versus distance (m) on the x-axis (-5 to 5). Five curves are shown: 'No frame' (dashed black line, highest), 'Single frame' (dashed blue line), 'Grading frame' (solid red line), 'Double frame' (solid red line), and 'Tower earthing' (solid red line, lowest). Markers on the x-axis indicate the locations of the tower legs and the cabinet. + +**Figure III.11 – Profile of touch voltage (pu, Base: T-EPR) for cabinet between the tower legs. +Profile: X direction, in centre line of the PGE frame** + +![Figure III.12: Profile of touch voltage (pu) for cabinet between the tower legs. Profile: X direction, in centre line of the tower-earthing electrodes. The graph shows touch voltage (pu) on the y-axis (0.0 to 0.6) versus distance (m) on the x-axis (-5 to 5). Three curves are shown: 'No frame' (dashed black), 'Single frame' (dotted blue), and 'Double frame' (solid red). The 'No frame' curve peaks at approximately 0.4 pu at ±4 m. The 'Single frame' and 'Double frame' curves are lower, peaking at approximately 0.25 pu at ±4 m. Labels 'Grading frame' and 'Tower earthing' point to specific locations on the x-axis.](64aba6d3bacc69b7b90f08e02f2d5efe_img.jpg) + +Figure III.12: Profile of touch voltage (pu) for cabinet between the tower legs. Profile: X direction, in centre line of the tower-earthing electrodes. The graph shows touch voltage (pu) on the y-axis (0.0 to 0.6) versus distance (m) on the x-axis (-5 to 5). Three curves are shown: 'No frame' (dashed black), 'Single frame' (dotted blue), and 'Double frame' (solid red). The 'No frame' curve peaks at approximately 0.4 pu at ±4 m. The 'Single frame' and 'Double frame' curves are lower, peaking at approximately 0.25 pu at ±4 m. Labels 'Grading frame' and 'Tower earthing' point to specific locations on the x-axis. + +**Figure III.12 – Profile of touch voltage (pu, Base: T-EPR) for cabinet between the tower legs. +Profile: X direction, in centre line of the tower-earthing electrodes** + +![Figure III.13: Profile of touch voltage (pu) for cabinet between the tower legs. Profile: direction 45° through the centre point of the grading electrode frame. The graph shows touch voltage (pu) on the y-axis (0.0 to 0.6) versus distance (m) on the x-axis (-6 to 6). Four curves are shown: 'No frame' (dashed black), 'Single frame' (dotted blue), 'Double frame' (solid red), and 'Tower frame' (solid brown). The 'No frame' curve peaks at approximately 0.4 pu at ±4 m. The 'Single frame' curve peaks at approximately 0.2 pu at ±4 m. The 'Double frame' curve peaks at approximately 0.1 pu at ±4 m. The 'Tower frame' curve is the lowest, remaining near 0.0 pu. Labels 'Grading frame' and 'Tower frame' point to specific locations on the x-axis.](3c47f29e8e1963959009844c7f3ee025_img.jpg) + +Figure III.13: Profile of touch voltage (pu) for cabinet between the tower legs. Profile: direction 45° through the centre point of the grading electrode frame. The graph shows touch voltage (pu) on the y-axis (0.0 to 0.6) versus distance (m) on the x-axis (-6 to 6). Four curves are shown: 'No frame' (dashed black), 'Single frame' (dotted blue), 'Double frame' (solid red), and 'Tower frame' (solid brown). The 'No frame' curve peaks at approximately 0.4 pu at ±4 m. The 'Single frame' curve peaks at approximately 0.2 pu at ±4 m. The 'Double frame' curve peaks at approximately 0.1 pu at ±4 m. The 'Tower frame' curve is the lowest, remaining near 0.0 pu. Labels 'Grading frame' and 'Tower frame' point to specific locations on the x-axis. + +**Figure III.13 – Profile of touch voltage (pu, Base: T-EPR) for cabinet between the tower legs. +Profile: direction 45° through the centre point of the grading electrode frame** + +For the judgement of the effectiveness of the PGE frame, the profiles are given for the following investigated options: + +- no PGE frame (solid brown profile); +- single PGE frame (dotted blue profile); +- double PGE frames (solid red profile). + +The electrode potentials are the following for the basic conditions given in clause III.2.1 a). + +| Cabinet location | Electrode potentials in V | | | +|------------------|---------------------------|--------------|--------------| +| | Applied PGE frame | | | +| | None | Single frame | Double frame | +| Between legs | 2746 | 2554 | 2530 | +| Beside the tower | 2746 | 1870 | 1844 | + +It is worth mentioning that when dividing the above voltage values by 1000 A, the earthing resistance of the electrode system will be obtained. + +Considering that the profiles are given as normalized values, neither the value of $\rho$ nor the injected current magnitude affects the results. + +The vertical scale of the plots is per unit (pu). The base is the electrode potential rise (T-EPR). + +Small filled or empty circles placed above the length scale indicate the positions of the PGE frame or the tower-earthing frame mesh along the profile direction. These help in the qualitative analysis of the effectiveness of the applied grading electrodes. + +The pu value can easily be recalculated to voltage relevant to an actual line condition on the basis of the information given in Appendix I, particularly in Table I.1. + +**For example**, with a touch voltage $u_t = 0.15$ pu. (Corresponds to Figure III.8, i.e., cabinet beside the tower, use of single PGE frame, location side of the cabinet just above the PGE frame.) + +The tower holding the RBS should belong to a line characterized by: + +- 1) average tower-earthing resistance of 25 $\Omega$ ; +- 2) two shield-wires; +- 3) mean span around 330 m (no span correction factor can be considered); +- 4) phase-to-earth fault current $I_{ef} = 15$ kA. + +Taking into consideration conditions 1) and 2), the tower-earthing potential rise taken from Table I.1 is: $U_b = 5589$ V/10 kA. + +The value of the touch voltage when considering condition 4) as well is obtained as follows: + +$$U_t = u_t \times U_b \frac{I_{ef}}{10} = 0.15 \times 5589 \frac{15}{10} = 0.15 \times 8384 = 1258 \text{ V}$$ + +The touch voltages relevant to the three investigated PGE frame options are: + +| Touch voltage | Applied PGE frame | | | +|--------------------------------|-------------------|--------|--------| +| | None | Single | Double | +| pu | 0.805 | 0.15 | 0.08 | +| For the actual condition, in V | 6751 | 1258 | 671 | + +#### d) *Analysis of the results* + +The presented profiles clearly show the effectiveness of the PGE frames in reducing the touch and step voltages. The PGE effect is shown at the side of the cabinet in the X direction profiles going through the centre line of the PGE frame (see Figures III.8 and III.11), while it is shown at the corner region of the cabinet in 45° profiles (see Figures III.10 and III.13). The Y direction profile for that arrangement, when the cabinet is beside the tower (see Figure III.9), provides values both for the surrounding area of the cabinet and for that of the tower legs. + +###### 1) *Touch voltage reduction effect of the grading* + +The reduction effect of the grading frames can be characterized by the following touch voltage values: + +| Application of the grading | Touch voltage range | Remarks | +|----------------------------|-----------------------|----------------------------------| +| None | 0.33 to 0.4 to 0.8(*) | (*) For cabinet beside the tower | +| Single frame | 0.15 to 0.20 | Above the grading frame | +| Double frame | 0.05 to 0.10 | In the zone above the frames | + +The reduction effect of the grading frames on the touch voltage can be summarized in the following statements: + +- A single PGE frame reduces the touch voltage by a factor of about 0.5 in relation to that condition when no PGE frame is applied. This reduction level occurs in a narrow zone just above the PGE electrode. The reduction rate can be even below 0.25, when the cabinet is beside the tower. +- The application of a second grading frame provides an additional reduction rate of 0.33 to 0.50. This reduction level affects a wider zone above the double PGE frames. + +###### 2) *Effect on the step voltage of the PGE* + +The step voltage is given by the gradient (steepness) of the earth potential profiles. The following statements can characterize the effect of the PGE electrode system on the step voltage: + +- The application of the grading frames practically does not affect the step voltage outside the outer grading frame (see, e.g., Figures III.11 and III.12). +- The step voltage is significantly reduced in the zone above the double PGE electrode frames. +- The step voltage is practically identical for the single and double PGE frame systems outside the outer grading frame. + +### III.2.2 Conclusions and proposals + +#### a) *Conclusions* + +The use of the PGE system effectively reduces the touch voltage to the cabinet body. This is a key issue for the safety of staff working beside the RBS cabinet. Therefore, the use of the PGE system is reasonable in any case and absolutely necessary in case of cabinets located beside the tower. + +The PGE reduces the step voltage as well. However, in the case of a single PGE frame this reduction is limited to a narrow path just above the PGE electrode. The step voltage is more effectively reduced by double PGE frames, especially in the zone above the double PGE frames. + +The PGE system does not reduce the step voltage in the area outside of the PGE system. It is worth mentioning that the reduction of the step voltage is not a key safety issue in the outside zone. Such kind of step voltage can occur in the surrounding area of any HV power line tower. No action is made to reduce this step voltage. According to long time experiences no injuries to people have been reported due to step voltages, which can occur in the surrounding area of power line towers. + +#### b) *Proposals for the application of the PGE* + +In order to avoid unsafe level of step and touch voltages, when approaching and entering the equipment cabinet, PGE electrode frames shall surround the cabinet. The electrode arrangements are shown in Figures III.14 and III.15 respectively for two typical cabinet locations, i.e., between the tower legs or beside the tower. Regarding the implementation of the PGE system, the following guidance can be stated: + +- The laying depth of the earth electrodes should be 0.3 m. +- The minimum size of the electrode conductor should be 3.5 by 30 mm zinc-coated flat steel or cylindrical steel with a diameter of 20 mm. +- The PGE electrode shall be bonded both to the cabinet earth and to the legs of the tower at least at two corners diagonally, when the cabinet is located between the legs (see Figure III.14). +- If necessary, two vertical earth rods should also be installed and connected to the earthing system. +- When a single PGE frame is applied, it should be laid around the cabinet at a distance of 0.6 m from the periphery of the cabinet, including the metallic steps if any. +- When a double PGE frame earth is applied, the frames should be placed $\pm 0.3$ m from the centre line assumed at a distance of 0.6 m from the periphery of the cabinet; i.e., the inner and outer frame earths should be laid 0.3 m and 0.9 m distance from the periphery of the cabinet, respectively. The use of this kind of double frame earth is preferable in case of stringent conditions resulting in high potential rise especially for cabinets located beside the tower. + +![Diagram (a) showing the application of a single PGE frame. It depicts a tower with four square panels and a central cabinet. A single grading earth frame is shown around the cabinet, connected to earth rods. Dimensions of 0.6 m are indicated for the frame's width and depth. The tower's earth connection is labeled 'tower earth'. A coordinate system with X and Y axes is shown.](51d4540605fdfa2c090638305022143b_img.jpg) + +Diagram (a) illustrates the arrangement of a single PGE frame. A tower structure is shown with four square panels. A cabinet is located at the base. A single grading earth frame is installed around the cabinet, connected to earth rods. The frame has a width and depth of 0.6 m. The tower's earth connection is labeled 'tower earth'. A coordinate system with X and Y axes is shown. + +Diagram (a) showing the application of a single PGE frame. It depicts a tower with four square panels and a central cabinet. A single grading earth frame is shown around the cabinet, connected to earth rods. Dimensions of 0.6 m are indicated for the frame's width and depth. The tower's earth connection is labeled 'tower earth'. A coordinate system with X and Y axes is shown. + +a) Application of single PGE frame + +![Diagram (b) showing the application of a double PGE frame. It depicts a tower with four square panels and a central cabinet. A double grading earth frame is shown around the cabinet, connected to earth rods. Dimensions of 0.3 m, 0.9 m, and 0.3 m are indicated for the frame's width and depth. The tower's earth connection is labeled 'tower earth'. A coordinate system with X and Y axes is shown. The text 'K.57(16)_FIII.14' is present.](01832e59ebad7ada5e790de6f90cc9b6_img.jpg) + +Diagram (b) illustrates the arrangement of a double PGE frame. A tower structure is shown with four square panels. A cabinet is located at the base. A double grading earth frame is installed around the cabinet, connected to earth rods. The frame has a width of 0.9 m and a depth of 0.3 m. The tower's earth connection is labeled 'tower earth'. A coordinate system with X and Y axes is shown. The text 'K.57(16)\_FIII.14' is present. + +Diagram (b) showing the application of a double PGE frame. It depicts a tower with four square panels and a central cabinet. A double grading earth frame is shown around the cabinet, connected to earth rods. Dimensions of 0.3 m, 0.9 m, and 0.3 m are indicated for the frame's width and depth. The tower's earth connection is labeled 'tower earth'. A coordinate system with X and Y axes is shown. The text 'K.57(16)\_FIII.14' is present. + +b) Application of double PGE frame + +**Figure III.14 – Arrangement of the PGE system in case of cabinet located beside the tower** + +![Figure III.15 shows two diagrams illustrating the arrangement of the PGE system in case of cabinet located between the tower legs. Diagram (a) shows the application of a single PGE frame, with dimensions 0.6 m and 0.6 m. Diagram (b) shows the application of a double PGE frame, with dimensions 0.3 m, 0.9 m, and 0.3 m. Both diagrams show a cabinet, tower earth, and grading earth frames.](c2c4e63ebb9afc1ab64e39a159890e0f_img.jpg) + +a) Application of single PGE frame + +b) Application of double PGE frame + +Figure III.15 shows two diagrams illustrating the arrangement of the PGE system in case of cabinet located between the tower legs. Diagram (a) shows the application of a single PGE frame, with dimensions 0.6 m and 0.6 m. Diagram (b) shows the application of a double PGE frame, with dimensions 0.3 m, 0.9 m, and 0.3 m. Both diagrams show a cabinet, tower earth, and grading earth frames. + +**Figure III.15 – Arrangement of the PGE system in case of cabinet located between the tower legs** + +## III.3 Estimation of minimum length values + +For orientation purposes, estimated values are derived for the earthing electrode potentials equal to the isolation voltage levels considered in Appendix I. + +The $\rho/R$ value is needed for the estimation of the minimum length values by the expression III-4. The estimation is based on the representation of the tower-earthing resistance $R$ by an equivalent hemisphere. The following relation applies between the equivalent radius $r_{eq}$ of the hemisphere and $R$ : + +$$R = \frac{\rho}{2\pi r_{eq}} \quad (\text{III-5})$$ + +The following expression is obtained for the $\rho/R$ ratio with the rearrangement of the above formula: + +$$\frac{\rho}{R} = 2\pi r_{eq} \quad (\text{III-6})$$ + +The formula III-6 clearly shows that the $\rho/R$ value is linked with the $r_{eq}$ by the multiplier $2\pi$ . + +The $\rho/R$ ratios are identified by the following technique for practical purposes. The earthing system of the tower footing, as a whole, is simulated by the Cdegs code [b-Cdegs] for a series of actual arrangements (in fact for 21 different cases). In the calculations, 1000 A (arbitrary value) is injected to the electrode system. The Cdegs code solves the electromagnetic field problem of the inputted electrode system embedded in homogeneous earth with a given specific soil resistivity $\rho$ . (The Cdegs code would allow the calculations for stratified earth structure as well.) The value of $\rho$ has, arbitrarily, been selected to 50 $\Omega\text{m}$ in the simulation calculations. One of the results of the + +calculation is the potential rise of the electrode with respect to the remote earth. The earthing resistance, $R$ , of the tower-earthing system is obtained, by definition, as the ratio of the calculated potential rise to the injected current considered in the calculation, i.e., 1000 A. Using the calculated $R$ value and the value of $\rho$ assumed in the calculation, the $\rho/R$ ratio is calculated for each simulated earthing electrode structure. It is worth mentioning that the $\rho/R$ ratio depends neither on the value of $\rho$ nor on the value of the injected current considered in the simulation calculations. + +The structure and geometrical sizes of the earth electrode of each tower leg are demonstrated in Figure III.16. + +![Figure III.16: Structure and geometrical sizes of the earth electrode of a tower leg. The diagram shows a cross-section of a tower leg foundation. A concrete foundation is shown above ground, with a height 'h' indicated. Below the foundation, an earthing electrode frame, made of circular steel with a diameter of 28 mm, is embedded. An earthing conductor, made of tinned flat steel (40 x 5 mm), is connected to the frame. The frame has a width 'b' and a height 'a'. The diagram is labeled K.57(16)_FIII.16.](b4b91e1f5ced9a2bc4a7f3b038cf3fb6_img.jpg) + +Figure III.16: Structure and geometrical sizes of the earth electrode of a tower leg. The diagram shows a cross-section of a tower leg foundation. A concrete foundation is shown above ground, with a height 'h' indicated. Below the foundation, an earthing electrode frame, made of circular steel with a diameter of 28 mm, is embedded. An earthing conductor, made of tinned flat steel (40 x 5 mm), is connected to the frame. The frame has a width 'b' and a height 'a'. The diagram is labeled K.57(16)\_FIII.16. + +**Figure III.16 – Structure and geometrical sizes of the earth electrode of a tower leg** + +The foundation of a tower is composed of either four legs (typical for a self-supporting tower foundation) or two legs (typical for an H-frame suspension tower). Correspondingly to these options, the calculations have been performed for earthing electrode arrangements containing four or two frame electrodes (see in the 1st column of Table III.1). The spacing between the legs ( $f_1$ and $f_2$ ) of the foundation, the lateral sizes ( $a$ and $b$ ) of the frame electrode, and the depth of the earthing electrode identify geometrical sizes of the electrode systems according to Table III.1. + +The $\rho/R$ values calculated for 21 earthing system structures are plotted in the last column of Table III.1. Taking $\rho/R = 18$ , which will cover about half of the values in the referred table, we get with formula III-4: + +$$x_{\min} = \frac{1}{2\pi} 18 \frac{V_e}{V_x} = 2.9 \frac{V_e}{V_x} \quad (\text{III-7})$$ + +When considering: + +- the earthing electrode potentials according to the isolating voltage levels used in Appendix I: + +$$V = 10 \text{ kV}, 15 \text{ kV}, 20 \text{ kV} \text{ and } 50 \text{ kV}$$ + +- the permissible stipulated no load earth potentials at the conversion cabinet for copper telecom cable or at the junction points: + +$$V_x = 650 \text{ V or } 1 \text{ kV}, 1.5 \text{ kV} \text{ and } 2 \text{ kV}$$ + +the minimum lengths of the junction section obtained from formula III-7 are given in Table III.2. + +**Table III.1 – Examples of values for the parameter $\rho/R$ for different tower-earthing arrangements** + +| Arrangement | | Typical voltage level [kV] | Case code | Sizes of the frame electrode [m] | | | | | $\rho/R$ | | +|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--|----------------------------|-----------|----------------------------------|-------|-----------------------|-----|-------|----------|--| +| | | | | Legs spacing a) | | Lateral b) | | Depth | | | +| | | | | $f_1$ | $f_2$ | $a$ | $b$ | | | | +| Diagram of a self-supporting tower foundation with four legs. Spacing f1 and f2 are shown between legs. Dimensions a and b are shown for the frame electrode.
Self-supporting tower foundation | | 120 | 1 | 3.6 | | 1.3 | | 1.8 | 13.3 | | +| | | 120 | 2 | 3.7 | | 1.3 | | 1.8 | 13.5 | | +| | | 220 | 3 | 4.5 | 4.0 | 1.4 | | 1.6 | 14.1 | | +| | | 120 | 4 | 4.8 | | 1.6 | | 1.6 | 15.5 | | +| | | 120 | 5 | 7.2 | 4.3 | 1.4 | | 1.8 | 15.8 | | +| | | 120 | 6 | 4.5 | | 2.0 | | 1.9 | 17.1 | | +| | | 220 | 7 | 6.0 | | 1.7 | | 1.8 | 17.4 | | +| | | 400 | 8 | 6.8 | | 1.7 | | 1.6 | 17.6 | | +| | | 220 | 9 | 6.5 | | 1.7 | | 2.0 | 18.2 | | +| | | 120 | 10 | 6.0 | | 1.9 | | 2.4 | 19.3 | | +| | | 400 | 11 | 7.5 | 5.5 | 2.0 | | 2.0 | 19.4 | | +| | | 750 | 12 | 9.0 | | 2.2 | | 1.8 | 21.9 | | +| | | 400 | 13 | 8.2 | | 2.3 | | 2.4 | 22.9 | | +| | | 220 | 14 | 7.0 | | 2.8 | | 2.0 | 23.1 | | +| | | 750 | 15 | 10.0 | | 2.4 | | 2.9 | 25.7 | | +| | | 220 | 16 | 9.0 | | 3.0 | | 2.8 | 27.3 | | +| | | 750 | 17 | 11.0 | | 3.0 | | 4.1 | 31.2 | | +| Diagram of an earthing electrode system of a guyed H-frame suspension tower. It shows two vertical legs with dimensions a, b, and f.
Earthing electrode system of guyed H-frame suspension tower | | 400 c) | 18 | 19.0 | | 1.2 | | 1.6 | 9.7 | | +| | | 120 | 19 | 5.4 | | 4.2 | 1.8 | 2.5 | 15.5 | | +| | | 220 | 20 | 18.0 | | 3.2 | 2.5 | 2.9 | 18.1 | | +| | | 750 c) | 21 | 26.4 | | 2.9 | 1.1 | 5.3 | 18.4 | | + +a) One value is only given when the spacing sizes between the legs of the tower foundation are identical, i.e., $f_1 = f_2 = f$ , or the tower foundation consists only of two legs with spacing $f$ (see the upper and lower schemes in the 1st column of the table, respectively). + +b) One value is only given when the lateral sizes of the frame type earthing electrode are identical, i.e., $a = b$ . + +c) Earthing electrode system of guyed H-frame suspension tower. + +**Table III.2 – Minimum required lengths of the junction section corresponding to the isolation voltage levels (Appendix I) and admissible Z-EPR at the junction point** + +| Isolation voltage level, $V$ [kV] | Minimum length [m] | | | | +|-----------------------------------|--------------------------------------------------------------|---------------------------------------------|------|------| +| | to conversion cabinet for copper telecom cable a) | of the junction section | | | +| | | Admissible EPR at the junction point, $V_x$ | | | +| | | 650 V | 1 kV | 2 kV | +| 10 | 44 | 29 | 19 | 14 | +| 15 | 67 | 43 | 29 | 22 | +| 20 | 28 | 58 | 39 | 29 | +| 50 | 221 | 144 | 96 | 72 | + +a) See Figures 5 and 6. + +# Bibliography + +- [b-IEC 71] IEC 60071-1:2006, *Insulation co-ordination - Part 1: Definitions, principles and rules*. +- [b-Sollerkvist] Sollerkvist (F.J.), Varju (G.), Károlyi (K.): Sophisticated multiconductor modelling in the frequency domain, Part 1: Numerical solution, Part 2: Case studies; *COST 261 Workshop*, Cagliari 2000. +- [b-Favez] Favez (B.), Gouqul (J.C.): Contribution of studies on problems resulting from the proximity of overhead lines with underground metal pipe lines. *CIGRÉ* 36.04, 1970. +- [b-Cdegs ] Cdegs software package of the Safe Engineering Services & Technologies Ltd., Montreal, Canada. +- [b-ITU-T Handbook] ITU-T Handbook, Directives, Volume II, *Calculating induced voltages and currents in practical cases*, Chapter 5, "Calculation of conductive coupling", ITU, Geneva 1999. + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.61-202510-I_PDF-E/raw.md b/marked/K/T-REC-K.61-202510-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..f4ec256aa4b348fecff610a4be1693ad15343bf4 --- /dev/null +++ b/marked/K/T-REC-K.61-202510-I_PDF-E/raw.md @@ -0,0 +1,759 @@ + + +# Recommendation **ITU-T K.61 (10/2025)** + +SERIES K: Protection against interference + +--- + +**Guidance on measurement and numerical +prediction of electromagnetic fields for +compliance with human exposure limits for +telecommunication installations** + +![ITU logo](390120de4fe440c42fea8154fcaad334_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with white lines representing latitude and longitude, and the letters 'ITU' in a bold, blue, sans-serif font overlaid on the globe. + +ITU logo + + + +# Recommendation ITU-T K.61 + +# Guidance on measurement and numerical prediction of electromagnetic fields for compliance with human exposure limits for telecommunication installations + +## Summary + +Recommendation ITU-T K.61 helps telecommunication operators to verify compliance with radio frequency electromagnetic field exposure standards promulgated by local or national authorities. This Recommendation provides guidance on measurement methods that can be used to achieve a compliance assessment. It also provides guidance on selecting numerical methods suitable for exposure prediction in various situations. + +## History\* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T K.61 | 2003-09-06 | 5 | 11.1002/1000/6505 | +| 2.0 | ITU-T K.61 | 2008-02-29 | 5 | 11.1002/1000/9139 | +| 3.0 | ITU-T K.61 | 2018-01-13 | 5 | 11.1002/1000/13447 | +| 4.0 | ITU-T K.61 | 2025-10-22 | 5 | 11.1002/1000/16424 | + +## Keywords + +Electromagnetic fields (EMF), EMF calculations, EMF measurements, exposure assessment. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, and information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2025 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|-------------------|------------------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 3.1 | Terms defined elsewhere ..... | 2 | +| 3.2 | Terms defined in this Recommendation ..... | 2 | +| 4 | Abbreviations and acronyms ..... | 2 | +| 5 | Conventions ..... | 3 | +| 6 | General principles ..... | 3 | +| 6.1 | Quantities being measured ..... | 4 | +| 6.2 | Typical situations..... | 5 | +| 7 | Technical considerations ..... | 5 | +| 7.1 | Averaging ..... | 5 | +| 7.2 | Quantities..... | 6 | +| 7.3 | Field regions ..... | 6 | +| 7.4 | Shadowing and scattering..... | 7 | +| 7.5 | Variability of the source ..... | 8 | +| 8 | Measurements ..... | 8 | +| 8.1 | Measurement instrumentation ..... | 8 | +| 8.2 | Evaluation of measurement uncertainties..... | 11 | +| 8.3 | Probe selection..... | 11 | +| 8.4 | Procedures ..... | 12 | +| 8.5 | Safety precautions ..... | 12 | +| 8.6 | Field region..... | 12 | +| 8.7 | Multiple sources ..... | 12 | +| 8.8 | Time and spatial variability ..... | 12 | +| 9 | Compliance with the limit: measurement results processing ..... | 13 | +| 9.1 | Identification of individual sources ..... | 13 | +| 9.2 | Intermittent sources ..... | 14 | +| 9.3 | Base stations for mobile communication systems ..... | 14 | +| Appendix I | – Calculation methods..... | 15 | +| I.1 | General ..... | 15 | +| I.2 | Methods description ..... | 15 | +| I.3 | Other near-field models ..... | 16 | +| I.4 | Practical problems ..... | 17 | +| Appendix II | – Identification and measurement of the main source of radiation ..... | 18 | +| II.1 | Treatment of non-conformities – Exceeding the exposure limits ..... | 18 | +| II.2 | Confirmation measurement ..... | 18 | +| Bibliography..... | | 19 | + +# Introduction + +This Recommendation helps telecommunication operators to verify compliance with radio frequency electromagnetic field (RF-EMF) exposure standards promulgated by local or national authorities. Guidance on the need to perform an exposure assessment for a telecommunication installation, such as a base station, is provided in [ITU-T K.52]. Indications on the process for putting a telecommunication installation, such as a base station into operation, are provided in [ITU-T K.100]. The assessment is based on the evaluation of the RF-EMF exposure and on accessibility considerations. The RF-EMF exposure evaluation can be carried out by measurement or numerical prediction. + +This Recommendation defines tools, methods and procedures that can be used to achieve a compliance assessment. The compliance with RF-EMF exposure standards can be achieved by measurement of electromagnetic field strength, provided that calibrated instruments are used and measurement uncertainty is correctly expressed. + +# Recommendation ITU-T K.61 + +# Guidance on measurement and numerical prediction of electromagnetic fields for compliance with human exposure limits for telecommunication installations + +# 1 Scope + +This Recommendation deals with measurements used for radio frequency electromagnetic field (RF-EMF) strength evaluation to verify that human exposure limits are not exceeded by EMFs produced by telecommunication installations, such as base stations as defined in [IEC 62232], in the frequency range 9 kHz to 300 GHz. This Recommendation also provides guidance on computational methods that can be used to achieve a compliance assessment. + +Contact with current exposure due to conductive objects irradiated by an electromagnetic field is not covered in this Recommendation. + +The exposure due to the use of mobile handsets or other radiating devices used in close proximity to the human body is not covered. Also, the exposure due to the use of cordless telephone systems and stationary sets intended for the use in wireless telecommunication networks such as digital enhanced cordless telecommunications (DECT), wireless local area network (WLAN), Bluetooth, etc. is not covered. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.52] Recommendation ITU-T K.52 (2024), *Guidance on complying with limits for human exposure to electromagnetic fields*. +- [ITU-T K.70] Recommendation ITU-T K.70 (2020), *Mitigation techniques to limit human exposure to EMFs in the vicinity of radiocommunication stations*. +- [ITU-T K.100] Recommendation ITU-T K.100 (2024), *Measurement of radio frequency electromagnetic fields to determine compliance with human exposure limits when a base station is put into operation*. +- [ITU-R BS.1698] Recommendation ITU-R BS.1698 (2005), *Evaluating fields from terrestrial broadcasting transmitting systems operating in any frequency band for assessing exposure to non-ionizing radiation*. +- [IEC 62232] IEC 62232 (2025), *Determination of RF field strength, power density and SAR in the vicinity of base stations for the purpose of evaluating human exposure*. +- [IEC 62479] IEC 62479 (2010), *Assessment of the compliance of low-power electronic and electrical equipment with the basic restrictions related to human exposure to electromagnetic fields (10 MHz to 300 GHz)*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 far field region** [b-IEC 60050 712]: That region of the electromagnetic field of an antenna wherein the predominant components of the field are those which represent a propagation of energy and wherein the angular field distribution is essentially independent of the distance from the antenna. + +NOTE 1 – In the far field region, all the components of the electromagnetic field decrease in inverse proportion to the distance from the antenna. + +NOTE 2 – For a broadside antenna having a maximum overall dimension $D$ which is large compared to the wavelength $\lambda$ , the far field region is commonly taken to exist at distances greater than $2D^2/\lambda$ , from the antenna in the direction of maximum radiation. + +**3.1.2 radiating near field (region)** [b-IEC 60050 712]: That region of space between the reactive near field region and the far field region, wherein the predominant components of the electromagnetic field are those which represent a propagation of energy, and wherein the angular field distribution is dependent upon the distance from the antenna. + +NOTE – If the antenna has a maximum overall dimension which is not large compared to the wavelength, the radiating near field region may not be identifiable in practice. + +**3.1.3 wavelength** [b-IEC 60050 103]: Distance, in the direction of propagation of a sinusoidal wave, between two successive points where the phases of the characteristic quantity differ by $2\pi$ radians. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 actual maximum (max) approach:** Evaluation method of radio frequency electromagnetic field (RF-EMF) exposure taking into account the actual maximum thereof. + +NOTE – For further information, see [IEC 62232], [ITU-T K.52], [ITU-T K.100]. + +**3.2.2 radio frequency (RF):** Any frequency at which electromagnetic radiation is useful for telecommunication. + +NOTE – In this Recommendation, radio frequency refers to the frequency range 9 kHz-300 GHz allocated by ITU-R Radio Regulations. + +**3.2.3 specific absorption (SA):** The quotient of the incremental energy (dW) absorbed by (dissipated in) an incremental mass ( $dm$ ) contained in a volume element ( $dV$ ) of a given density ( $\rho m$ ). + +NOTE – The specific absorption is expressed in units of joules per kilogram (J/kg). + +**3.2.4 specific absorption rate (SAR):** The time derivative of the incremental energy (dW) absorbed by (dissipated in) an incremental mass ( $dm$ ) contained in a volume element ( $dV$ ) of a given mass density ( $\rho m$ ). + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|----------------------------------------------| +| AF | Antenna Factor | +| APC | Automatic Power Control | +| APD | Absorbed Power Density | +| CF | Calibration Factor | +| DECT | Digital Enhanced Cordless Telecommunications | + +| | | +|------|-----------------------------------------| +| EIRP | Equivalent Isotropically Radiated Power | +| EM | Electromagnetic | +| EMF | Electromagnetic Field | +| FDTP | Finite-Difference Time-Domain | +| MOM | Method of Moments | +| MR | Multiple-Region | +| NEC | Numeric Electromagnetic Code | +| PC | Personal Computer | +| RF | Radio Frequency | +| RMS | Root Mean Square | +| SA | Specific Absorption | +| SAR | Specific Absorption Rate | +| WLAN | Wireless Local Area Network | + +# 5 Conventions + +None. + +# 6 General principles + +A procedure for achieving compliance with radio frequency electromagnetic field (RF-EMF) exposure limits is provided in [ITU-T K.52]. The steps needed to achieve compliance are: + +- 1) Identify appropriate compliance limits. +- 2) Determine whether an electromagnetic field (EMF) exposure assessment for the installation of equipment in question is needed. +- 3) If an EMF exposure assessment is needed, it may be performed by calculations or measurement. +- 4) If the EMF exposure assessment indicates that pertinent exposure limits may be exceeded in areas where people may be present, mitigation/avoidance measures should be applied. + +Additional information on RF-EMF exposure assessments can be found in [IEC 62232] and [IEC 62479], as well as [ITU-T K.70], [ITU-R BS.1698] and [b-CSN EN 50413]. It is also recommended to ensure that exposure assessment is conducted in accordance with the applicable national or regional standards and regulations. + +As defined in [ITU-T K.100], telecommunication installations with some predefined criteria may be put into operation without proceeding with detailed measurements or calculations. The more sophisticated assessment methods defined in this Recommendation are used to refine the zone boundaries obtained using [ITU-T K.52] or for complex situations where the methods of [ITU-T K.52] may be insufficient. For example, it may be useful to refine the results of [ITU-T K.52] where they indicate the appearance of an exceedance zone or occupational zone marginally. A measurement or more accurate calculation can help determine whether the zone determination is correct or is an artefact of the conservative estimation methods of [ITU-T K.52]. Another example where measurements may be needed is in complex scattering environments or for environments with a number of significant sources of electromagnetic (EM) radiation. + +To ensure accurate results and avoid overestimations, RF-EMF exposure assessments should be performed using the actual maximum transmitted power or equivalent isotropically radiated power + +(EIRP) of the radio transmitters. The actual maximum approach is described in [IEC 62232], [ITU-T K.52] and [ITU-T K.100]. + +## 6.1 Quantities being measured + +Most documents provide RF-EMF exposure limits in terms of basic restrictions and reference (or derived) levels. The basic restrictions address the fundamental quantities that determine the physiological response of the human body to EMFs. Basic restrictions apply to situations with the body present in the field. The basic restrictions for human exposure are expressed as the specific absorption rate (SAR), specific absorption (SA), absorbed power density (APD) and current density. SAR, SA, APD and current density assessments are not within the scope of this Recommendation; more information can be found in [IEC 62232] and [b-IEC PAS 63446]. + +As the basic restrictions are difficult to measure directly, most RF-EMF exposure standards and recommendations provide derived reference levels for electric field strength, magnetic field strength and power density. The reference levels apply to situations where the assessment of RF-EMF is not influenced by the presence of a body. The normative part of this Recommendation provides guidelines for the measurement of reference levels. + +Reference levels may be exceeded if the exposure condition can be shown to produce SAR, SA, APD and induced current density below the basic restrictions. Therefore, Appendix I provides guidance on selecting computational procedures that can be used to calculate these metrics. + +$$SAR = \frac{d}{dt} \frac{dW}{dm} = \frac{d}{dr} \left( \frac{1}{\rho_m} \frac{dW}{dV} \right)$$ + +SAR is expressed in units of watts per kilogram (W/kg). + +SAR can be calculated by: + +$$SAR = \frac{\sigma E^2}{\rho_m}$$ + +$$SAR = c \frac{dT}{dt}$$ + +$$SAR = \frac{J^2}{\rho_m \sigma}$$ + +where: + +$E$ is the value of the electric field strength in body tissue in V/m + +$\sigma$ is the conductivity of body tissue in S/m + +$\rho_m$ is the density of body tissue in kg/m3 + +$c$ is the heat capacity of body tissue in J/kg°C + +$\frac{dT}{dt}$ is the time derivative of temperature in body tissue in °C/s + +$J$ is the value of the induced current density in the body tissue in A/m2 + +## 6.2 Typical situations + +The measurement problem typically approaches one of the following cases: + +- 1) The source of the RF-EMF and at least some of its characteristics are known. The RF-EMF from other sources is negligible for compliance considerations. The objective is to determine the compliance zones for this known source. + +- 2) The sources of the RF-EMF are not known. The objective is to determine compliance in a particular location, or to survey the EM fields in the out-of-band region to confirm that other EM sources can be neglected. +- 3) The objective is to determine compliance in a particular location, and if non-compliance is found, to determine the relative contribution of the sources to the non-compliance. + +In case 1, the emission frequency band should be known precisely. The transmitted power, polarization and the antenna pattern may be known approximately. Thus, the measurements can focus on to the frequency range of interest. [ITU-T K.52] or [IEC 62232] should be used to obtain an estimate of the field strength in order to determine appropriate instrumentation. + +In case 2, a survey of the entire frequency spectrum may be required. An alternative is measurement with a wideband probe that integrates various frequencies. Case 3 is an extension of case 2. If the initial measurement indicates non-compliance, frequency-selective measurements, an antenna and spectrum analyser, for example, are needed. + +Additional guidelines on how to conduct an RF-EMF exposure assessment and detailed descriptions of measurement and calculation methodologies can be found in [IEC 62232]. + +# **7 Technical considerations** + +## **7.1 Averaging** + +### **7.1.1 Time averaging** + +Limits are usually expressed as root mean square (RMS) values of a continuous wave averaged over a defined period. For example, the basic restrictions and reference levels specified in [b-ICNIRP] are to be averaged over any 6-minute period for local exposure and over any 30-minute period for whole-body exposure. Therefore, for time-dependant signals, an elaboration of measurement results (post-processing procedure) may be necessary for comparison with the limit. + +### **7.1.2 Spatial averaging** + +The basic restrictions typically comprise two categories: local limits and whole-body limits. The local limits are pertinent to localized exposures due to small radiators close to the body, such as mobile phones, and are to be averaged over a small mass or surface. The whole-body limits are to be averaged over the whole body and are applicable in the case of RF-EMF exposure from base stations in mobile networks and other telecommunication installations. + +The whole-body reference levels are generally intended to be spatially averaged values over the dimensions of the body of the exposed individual, but with the important proviso that the local basic restrictions or reference levels on exposure are not exceeded. + +For telecommunication installations, the highest field values occur close to the antennas in regions where the fields may vary appreciably on the scale of the size of the human body. In these cases, spatial averaging can be used to obtain a more accurate result. + +## **7.2 Quantities** + +Exposure standards usually refer to reference levels expressed as electric and magnetic field strengths or power density. They are individually measured only when it is required by the field properties related to the field regions. + +## **7.3 Field regions** + +The properties of EMFs need to be taken into consideration for their measurement and evaluation. For example: + +- measurement of both the electric and magnetic components may be necessary in the non-radiating near-field region; +- for numerical prediction, the far-field model usually leads to an overestimation of the field if applied in near-field regions. + +Therefore, it is important to be aware of the boundaries of each field region before starting a compliance procedure. Information about field regions is provided in [IEC 62232]. + +### 7.3.1 Reactive near-field zone + +The reactive near-field zone is the portion of the near-field region that is immediately surrounding the antenna and where the reactive field predominates. This region is commonly assumed to extend to a distance of one wavelength from the antenna. + +### 7.3.2 Reactive-radiative near-field region + +At the boundary to the reactive near-field zone, a transition region may be defined wherein the radiating field is beginning to be important compared with the reactive component. This outer region extends to a few (e.g., $3\lambda$ ) wavelengths from the electromagnetic source. + +### 7.3.3 Radiating near-field (Fresnel) zone + +The region of the field of an antenna between the reactive near-field and the far-field region, wherein the radiation field predominates. Although the radiation is not propagating as a plane wave, the electric and magnetic components can be considered locally normal; moreover, the ratio $E/H$ can be assumed constant (and almost equal to $Z_0$ , the intrinsic impedance of free space). This region exists only if the maximum dimension $D$ of the antenna is large compared with the wavelength $\lambda$ . + +### 7.3.4 Radiating far-field zone + +The region of the field where the angular field distribution is essentially independent of the distance from the antenna and the radiated power density [ $\text{W/m}^2$ ] is constant. The inner boundary of the radiating far-field region is defined by the larger value between $3\lambda$ and $2D^2/\lambda$ (i.e., the limit is $2D^2/\lambda$ if the maximum dimension $D$ of the antenna is large compared with the wavelength $\lambda$ ). In the far-field region, the field components are transverse and propagate as a plane wave. + +The above regions are shown in Figure 1 (where $D$ is supposed to be large compared with the wavelength $\lambda$ ) and the main properties of an electromagnetic field (EMF) in different field regions are shown in Table 1. + +![Figure 1: Field regions around an EM source. The diagram shows a horizontal axis representing the distance from the source, starting with an EM source symbol on the left. The axis is divided into four regions by vertical dashed lines at distances λ, 3λ, and 2D²/λ. The regions are labeled from left to right: 'Reactive near-field' (0 to λ), 'Reactive-radiating near-field' (λ to 3λ), 'Radiating (Fresnel) near-field' (3λ to 2D²/λ), and 'Radiating-far field' (beyond 2D²/λ). The label 'Distance from the source' is placed above the axis on the right, and the code 'K.61(18)_F01' is in the bottom right corner.](63e0c22852c26699d0bd095a2d796bab_img.jpg) + +Figure 1: Field regions around an EM source. The diagram shows a horizontal axis representing the distance from the source, starting with an EM source symbol on the left. The axis is divided into four regions by vertical dashed lines at distances λ, 3λ, and 2D²/λ. The regions are labeled from left to right: 'Reactive near-field' (0 to λ), 'Reactive-radiating near-field' (λ to 3λ), 'Radiating (Fresnel) near-field' (3λ to 2D²/λ), and 'Radiating-far field' (beyond 2D²/λ). The label 'Distance from the source' is placed above the axis on the right, and the code 'K.61(18)\_F01' is in the bottom right corner. + +**Figure 1 – Field regions around an EM source (the antenna maximum dimension $D$ is supposed to be large compared with the wavelength $\lambda$ )** + +**Table 1 – Main properties of electromagnetic field in different field regions** + +| | Reactive near-field | Reactive-radiating near-field | Radiating near-field | Radiating far-field | +|------------------------------------------|---------------------|-------------------------------|-----------------------------------------------------|--------------------------------------------------| +| Inner boundary | 0 | $\lambda$ | $3\lambda$ | $\text{Max}(3\lambda; 2D^2/\lambda)$ | +| Outer boundary | $\lambda$ | $3\lambda$ | $\text{Max}(3\lambda; 2D^2/\lambda)$ | $\infty$ | +| Power density
$S$ [W/m 2 ] | $S \leq E H $ | $S \leq E H $ | $S \leq E H $
$= \frac{ E ^2}{Z_0} = Z_0 H ^2$ | $S = E H $
$= \frac{ E ^2}{Z_0} = Z_0 H ^2$ | +| $E \perp H$ | No | No | Locally | Yes | +| $Z = E/H$ | $\neq Z_0$ | $\neq Z_0$ | $\approx Z_0$ | $= Z_0$ | + +## 7.4 Shadowing and scattering + +The RF-EMF exposure varies with spatial position due to the effect of reflections and scattering from adjacent conducting structures. The scale of this variability is a function of the wavelength. It is important to consider this variability in order to determine the locations of maximum exposure and to use spatial averaging as appropriate. + +Since the exposure standards specify the limits for the exposure of the human body, the effect of the body on the field pattern should be considered. For example, Figure 2 shows a situation where the presence of a human body would absorb part of the incident wave, creating a shadow region that precludes a reflection that would otherwise enhance the field at the position of the body. These types of effects, especially at microwave frequencies, can lead to an overestimation of the field during measurements or numerical calculations near reflecting objects. + +![Diagram illustrating multi-path alteration due to the presence of a human body. An antenna on the left emits waves towards a reflecting wall on the right. A human figure stands between them. Three paths are shown: 'no reflection' (direct path to the wall), 'direct' (path to the human), and 'reflection' (path reflecting off the ground surface). The ground is labeled 'Reflecting surface'. The diagram is labeled K.61(18)_F02.](410562339ce067fdc6fa41940c118658_img.jpg) + +``` + +graph LR + A[Antenna] -- "no reflection" --> W[Reflecting wall] + A -- "direct" --> H[Human body] + A -- "reflection" --> S[Reflecting surface] + S --> H + +``` + +Diagram illustrating multi-path alteration due to the presence of a human body. An antenna on the left emits waves towards a reflecting wall on the right. A human figure stands between them. Three paths are shown: 'no reflection' (direct path to the wall), 'direct' (path to the human), and 'reflection' (path reflecting off the ground surface). The ground is labeled 'Reflecting surface'. The diagram is labeled K.61(18)\_F02. + +**Figure 2 – An illustration of a multi-path alteration due to the presence of a human body** + +## 7.5 Variability of the source + +Telecommunication sources are sometimes variable. Variability of transmitted power and antenna patterns is especially important. This variability presents a special challenge for measurements, since the exact state of the transmitter at the time of measurement may not be known. + +### 7.5.1 Power variability + +The exposure assessment must take into account either the configured maximum total radiated power or the actual maximum power or EIRP from the transmitter. The power transmitted in a telecommunication system could vary due to automatic power control (APC) or channel use + +variability. APC adjusts output power to compensate for adverse propagation conditions. Channel variability falls into two categories: + +- 1) Dynamic channel allocation, where the channels are turned on or off as needed; or +- 2) Variation in channel occupancy, where the amount of data transmitted over a channel varies; however, even if no data is transmitted, the channel carrier remains. Channel occupancy variation affects the modulation of the signal; however, this effect is expected to be small. + +### **7.5.2 Antenna variability** + +Certain telecommunication systems use active antennas that can dynamically vary their radiation pattern. The actual maximum approach described in [IEC 62232] takes into account the antenna pattern variability in the spatial domain. + +### **7.5.3 Intermittent sources** + +Certain sources used in telecommunications are intermittent. Such sources emit RF energy only if they need to transmit information. + +Such sources may operate in a regular manner, transmitting data at regular intervals or to a defined schedule. + +Such sources may also operate in an irregular manner, transmitting data only if activated by an operator or if a sufficient amount of data has been accumulated to trigger transmission. + +# **8 Measurements** + +## **8.1 Measurement instrumentation** + +### **8.1.1 Characteristics** + +The following general characteristics of measurement devices are important in their selection. + +#### **8.1.1.1 Frequency range** + +There are two classes: broadband and narrowband. + +- 1) Broadband devices (such as the commonly used electric and magnetic probes) do not give information on the frequency spectrum. Nevertheless, frequency-selective measurements on large bands are possible by using small broadband antennas (e.g., biconical, horn, etc.) or more sophisticated and expensive devices. +- 2) Narrowband devices are generally antennas with flat antenna factors (AFs) over limited spectrum ranges (e.g., dipole antennas) and can be used for frequency-selective measurement. + +#### **8.1.1.2 Antenna directivity** + +The antenna response may be isotropic or directional. + +For isotropic devices, the response is expected to be independent of the direction of the incident EMF. + +For directional devices, the response is expected to be dependent on the direction of the incident EMF. Directional devices are generally polarized and have axial symmetry in the radiation pattern. Thus, proper orientation of the device in 3 orthogonal axes is necessary for field reconstruction. + +#### **8.1.1.3 Quantity measured** + +The majority of devices measure either the electric field or the magnetic field. + +The distinction is important in the reactive field region. + +In the far-field region, it is possible to measure either the electric or the magnetic field component and determine the equivalent power density. However, measurement devices for the electric field component are usually preferred. The equivalent power density within the far-field region is obtained from the measured field by calculation, as shown in Table 1. + +### 8.1.2 Device selection + +The choice of devices for RF-EMF measurement is determined by certain factors, for instance: + +- the existing standards to be complied with (e.g., limits may be frequency-dependent); +- the number and the characteristics of RF-EMF sources; and +- the field regions (i.e., reactive near-field, radiating near-field, and far-field) in which the measurements are made. + +The choice of measurement equipment is strongly related to the measurement procedure. The accuracy of measurement results depends on measurement procedures as well as on the characteristics of the measurement instruments used. More information on uncertainty is provided in clause 8.2. + +### 8.1.3 Calibration requirements + +#### 8.1.3.1 Calibration factor + +For broadband probes, the calibration factor (CF) is defined by the following formula: + +$$CF = \frac{E_{ref}}{E_{meas}}$$ + +It is the ratio between the expected electric reference field strength ( $E_{ref}$ ) and the value ( $E_{meas}$ ) read on the personal computer (PC) or on a dedicated receiver unit. This factor is mainly a function of frequency and, in the presence of non-linearity error, of field strength. The CF is determined as a frequency function. For each frequency, the CF value shall be known with an uncertainty of less than 1 dB. Errors due to frequency interpolation are included in the tolerable uncertainty of CF. + +#### 8.1.3.2 Antenna factor + +The antenna factor (AF) is defined for antennas and frequency-selective probes as the ratio: + +$$AF = \frac{E_{ref}}{V} [m^{-1}]$$ + +where $E_{ref}$ [V/m] is the electric field strength at the probe and $V$ [V] is the voltage measured by the spectrum analyser. This factor is primarily a function of frequency but, in the presence of non-linearity error, it may depend on field strength, as well. The AF is determined as a frequency function. For each frequency, the AF value shall be known with an expanded uncertainty (i.e., 95% statistical confidence) of less than 2 dB. The maximum tolerable uncertainty also includes the error due to frequency interpolation (when needed). + +#### 8.1.3.3 Isotropy + +An isotropic probe is almost always useful in compliance measurements for a telecommunication installation. The isotropic response is usually achieved by a triaxial antenna system, where the three axes are arranged to be mutually orthogonal. The deviation from an ideal isotropic response is measured in the isotropy test. The deviation is called the isotropic error and in general it is a function of the incident wave direction. It can be evaluated: + +- by measuring the difference from a cosine response of each axis, if they are clearly spatially identified and a signal from each axis is available; or +- by checking the whole probe response, if it is not possible to clearly define the position of each axis or a single axis signal is not available. + +The mean deviation from the isotropic response should be less than 1 dB. + +#### 8.1.3.4 Linearity + +A linear response with respect to the field amplitude is required: a linearity error would mean that the antenna and the calibration factors are functions of the test field strength. Thus, the linearity test should be the starting point of the whole characterization process of the probe. The test is carried out, over as wide a dynamic range as possible, by verifying the relationship between radiated power and the electric field or voltage measured. The relationship is linear in logarithmic units: the uncertainty band on the linear regression shall have the same magnitude as the measurement uncertainty. If the condition is not fulfilled, a linearity error is probable and the following actions are suggested: + +- in the characterization process: CF or AF are measured for different amplitudes of the test wave and different results are obtained; +- in the compliance survey: differences due to field strength can be managed by widening the measurement uncertainty or by considering different factors for different field amplitudes (where it is possible). + +Checking the linearity at some frequencies may be useful. The maximum tolerable deviation from a linear response is 1 dB. + +#### 8.1.3.5 Pulsed signal + +Due to their modulation and their multiple-media access, radio-mobile digital systems have pulsed transmissions. Therefore, when the characterization is carried out with a continuous wave test field, it is necessary to verify whether a pulsed test field introduces any changes in the tested characteristics. + +If differences in CF and AF, as determined by a pulsed test wave and a continuous wave, are less than the relevant uncertainties, the measurement instruments can be used without regard to the type of signal they are measuring. + +#### 8.1.3.6 Multiple signal integration + +Verifying the correct integration of different signals with different frequencies is an important test for non-selective broadband probes. It means verifying that the measurement result is correctly given by an RMS formula: + +$$E_{rms} = \sqrt{\sum_i E_i^2}$$ + +The test can be easily carried out with two RF sources: results shall comply with the condition: + +$$20 \log_{10} \left\{ \frac{E_{mes} - \sqrt{E_1^2 + E_2^2}}{E_{mes}} \right\} < 0.5 \text{ dB}$$ + +where: + +$E_{mes}$ is the measured electric field + +$E_1$ and $E_2$ are the actual field values + +or less than the measurement uncertainty on the electric field or voltage. + +#### 8.1.3.7 Axial rejection + +The response of an axis irradiated by a cross-polarized incident wave is measured in the test. A low axial rejection could have important effects on the electric field strength measurement when it is determined as the RMS value of three orthogonal components. + +## 8.2 Evaluation of measurement uncertainties + +Measurement uncertainties for measurements of fields are the results of errors due to system instrumentation, field probe response and calibration and the extrapolation, interpolation and integration algorithms used to determine the averaged field. For evaluation and expression of uncertainties, see [IEC 62232] and [b-JCGM 100:2008]. + +The target expanded uncertainty for in situ field measurements is less than or equal to 4 dB, which is considered industry best practice. The expanded uncertainty for the RF exposure evaluation used for in situ RF EMF exposure measurements shall not exceed 6 dB. Under this condition, the evaluation result shall be compared directly to the exposure limit. However, the entity performing the uncertainty analysis also needs to be aware of the applicable regulation. More information can be found in [IEC 62232] or [b-CSN EN 50413]. + +## 8.3 Probe selection + +### 8.3.1 Probe size + +If measurements in the near field are being made, the dimension of the probe sensor should be less than one wavelength at the highest operating frequency. + +### 8.3.2 Frequency range + +General consideration: use broadband wherever possible (as it is simpler and shorter), but often a frequency-selective measurement is required (in general, when it is not possible to distinguish one main source and when the measurement results need an elaboration to be compared with an RMS limit). + +Selective measurement is usually necessary in the case of: + +- multiple sources with different limits; +- multiple sources to which different measurement techniques are recommended (e.g., post-processing for different mobile technologies or others); or +- when it is necessary to determine the relative contribution of multiple sources. + +### 8.3.3 Directivity + +A non-directional probe is preferred. + +## 8.4 Procedures + +Before performing a measurement of potentially non-compliant RF-EMF levels, an approximate assessment as described in [ITU-T K.52] should be performed. This will permit an estimate of the expected RF-EMF exposure, the boundaries of the compliance zones and consequently will help in the selection of appropriate test instruments and test procedures. + +## 8.5 Safety precautions + +Personnel should take appropriate safety precautions while performing measurements. If measurements are performed in the exceedance zone, precautions specified in [ITU-T K.52] should be followed. Also, precautions against indirect effects, such as contact currents, should be observed. + +## 8.6 Field region + +What is to be measured (E or H) depends on where (reactive or radiating field) the observer is and on the field impedance. + +- Reactive near-field: measure both the E and H components or evaluate the SAR. + +- Reactive radiating near-field: if no information on the field impedance is available, measure both the E and H fields; if information on the field impedance is available, it is possible to measure only one field component, provided that conservative results are obtained: + - Measure only E component if $\frac{E}{H} > Z_0 = 120 \times \pi [\Omega]$ i.e., high impedance EMF + - Measure only H component if $\frac{E}{H} < Z_0 = 120 \times \pi [\Omega]$ i.e., low impedance EMF +- Radiating near-field: measure only the E component, the free space impedance ( $Z_0$ ) is assumed (as differences are small compared with the measurement uncertainties). +- Radiating far-field: measure only the E component. + +For exposure at positions located very close to the source, determining the SAR instead of performing a field measurement may be preferable. + +## 8.7 Multiple sources + +The effects of multiple sources operating at different frequencies should be considered according to [b-ICNIRP] or the applicable RF-EMF exposure standard, usually in a weighted sum, where each individual source is prorated according to the limit applicable to its frequency. + +## 8.8 Time and spatial variability + +Multi-path reflections can create non-uniform field distributions. Therefore, to assess the whole-body human exposure, an averaging process is required. The field values should be determined at N points as described in Figure 3. Three points are basically recommended (Figure 3a), but if accuracy is required the number can be increased to six (Figure 3b), nine (Figure 3c), twenty (Figure 3d), etc., in accordance with national or regional standards and regulations. In all cases, the uncertainty of the evaluation should be determined. More information on spatial averaging can be found in [IEC 62232]. + +![Figure 3 shows four diagrams (a, b, c, d) illustrating measurement points for spatial averaging. (a) shows three measurement points at heights 1.1 m, 1.5 m, and 1.7 m. (b) shows six measurement points at heights 1.1 m, 1.5 m, and 1.7 m, with a horizontal spacing of 0.4 m between points at the same height. (c) shows nine measurement points at heights 1.1 m, 1.5 m, and 1.7 m, with a horizontal spacing of 0.2 m between points at the same height. (d) shows twenty measurement points at a height of 2 m, with a vertical spacing of 0.1 m between points.](595e9fd7e96f6b95bbaa6e6a45c32682_img.jpg) + +Figure 3 shows four diagrams (a, b, c, d) illustrating measurement points for spatial averaging. (a) shows three measurement points at heights 1.1 m, 1.5 m, and 1.7 m. (b) shows six measurement points at heights 1.1 m, 1.5 m, and 1.7 m, with a horizontal spacing of 0.4 m between points at the same height. (c) shows nine measurement points at heights 1.1 m, 1.5 m, and 1.7 m, with a horizontal spacing of 0.2 m between points at the same height. (d) shows twenty measurement points at a height of 2 m, with a vertical spacing of 0.1 m between points. + +Figure 3 – Measurement points for spatial averaging + +The formula for calculating spatially averaged field values is as follows: + +$$(E \text{ or } H) = \sqrt{\frac{\sum_{i=1}^N (E_i \text{ or } H_i)^2}{N}}$$ + +where: + +$N$ : is the number of points, i.e., three, six, nine, twenty, etc. + +Measurement should not be conducted close to metallic objects to avoid coupling with the probe. For example, it may be sufficient to keep the edge of the probe at least 3 "probe lengths" from the metallic object. + +In case of multiple sources, the measurement area should be divided into a grid of about one square metre and measurements should be performed at individual grid points. Large field gradients can exist in the near field of a radiator. Measurements should be performed sufficiently close together to accurately determine the compliance zone boundaries. + +In areas of expected time variability of the source, measurements may need to be performed over an extended time period. For example, in case of channel variability, measurements should be made during periods of peak usage. + +NOTE – Initial measurements in a grid or near the radiator, as described in this clause, yield the maximum point field values. These values represent the most conservative evaluation of the exposure. It is possible to define the compliance zones based on these conservative values. If a more refined estimation is desired, spatial averaging, as described in clause 7.1.2, should be used. + +# **9 Compliance with the limit: measurement results processing** + +## **9.1 Identification of individual sources** + +The probe used for external field measurements in determining compliance should generally be isotropic, non-directional and non-polarized. Also, the probe should not produce significant scattering of the incident electromagnetic field, and the leads from the sensor to the meter should not interact significantly with the field. However, such a probe cannot differentiate between different sources. + +Frequency-selective or directional measurements are needed to identify the contribution of individual sources. For example, a combination of an antenna and a spectrum analyser allows for a more precise measurement of individual frequency, direction and polarization field components. However, this makes the measurements more complicated as it is necessary to measure and sum three polarizations separately. Also, in complex scattering environments, it may be necessary to measure the fields in various directions. It is also possible to use the antenna and spectrum analyser combination to verify the frequency and origin of the emissions measured by the isotropic probe. + +In cases when non-conformity with exposure limits is found, the procedure for the identification of the main source of radiation, according to Appendix II, should be applied. + +## **9.2 Intermittent sources** + +Neither the isotropic wideband probe nor a spectrum analyser can measure the duration of an intermittent source. The field probe measures the maximum (peak) field value, while the spectrum analyser measures the maximum spectral density in the frequency domain. To obtain proper time-averaging, the duration of an intermittent transmission has to be determined from the operational requirements of the system. + +## **9.3 Base stations for mobile communication systems** + +The preferred method for RF-EMF measurements for base station emitters providing mobile wireless telecommunication services is to ensure that all radio channels or resources are occupied during the measurement. This may be verified by knowledge of the system operation or through examination of the signal with a combination of antenna and spectrum analyser. If measurements with all channels or resources occupied are not possible, then an extrapolation procedure should be used. Such procedures are described for various technologies of mobile telecommunication systems in [IEC 62232]. + +The last step is to calculate the total equivalent electric field strength, $E_{TOT}$ , that will be compared with the exposure limit. It is obtained by the RMS sum of the contribution from each transmission system (numbered by the index $k$ ): + +$$E_{TOT} = \sqrt{\sum_k E_k^2} \leq E_{lim}(f)$$ + +and when different limits are defined for different frequencies: + +$$\rho_E = \sqrt{\sum_k \frac{E_k^2}{E_{lim_k}^2}} \leq 1$$ + +Uncertainty: when conservative approximations (e.g., full traffic) are made during processing, the field strength resulting from the post-processing is compared with the exposure limit. + +If the power density has been evaluated, similar formulas apply and are given in [IEC 62232]. + +# Appendix I + +## Calculation methods + +(This appendix does not form an integral part of this Recommendation.) + +### I.1 General + +This appendix provides guidance in selecting calculation methods to assess compliance with EMF levels. There are several methods useful for determining compliance with exposure limits: + +- 1) finite-difference time-domain (FDTD); +- 2) multiple-region finite-difference time-domain (MR/FDTD); +- 3) synthetic model and ray tracing model; +- 4) hybrid ray tracing/FDTD methods; and +- 5) near-field antenna models such as the method of moments (MOM) and the numeric electromagnetic code (NEC). + +The selection of the appropriate numerical method depends on the following factors: + +- 1) the field zone where the exposure evaluation is required; +- 2) the quantities being evaluated (SAR or reference fields); and +- 3) the topology of the environment where the exposure occurs. + +The selection criteria are summarized in Table I.1: + +**Table I.1 – Selection of numerical techniques** + +| Field zone | Topology | Evaluated quantity | Suitable numerical technique | +|------------|-------------------------------------------------|--------------------|------------------------------| +| Near-field | Open | Field | FDTD, MOM | +| Near-field | Open | SAR | FDTD | +| Near-field | Closed, multiple scatterers | Field | FDTD, MOM | +| Near-field | Closed, multiple scatterers | SAR | FDTD, MR/FDTD | +| Far-field | Open | Field | Ray tracing, MOM | +| Far-field | Multiple scatterers (complex urban environment) | Field | Ray tracing | + +More detailed information on numerical techniques can be found in [IEC 62232]. + +### I.2 Methods description + +A brief description of the various methods and more information on calculation methods can be found in the following clauses. More details can be found in [IEC 62232]. + +#### I.2.1 FDTD + +The FDTD method is most useful for exposure assessment near an antenna or in confined locations with a complex scattering environment. The FDTD algorithm is the most widely accepted computational method for SAR modelling [b-Kunz]. The FDTD method offers great flexibility in modelling the heterogeneous structures of anatomical tissues and organs. + +The FDTD method can be used to predict field values in complex scattering environments by specifying appropriate boundary conditions or to predict SAR by specifying the dielectric properties and dimensions of the human body and appropriate boundary conditions for closed or open spaces, see [b-Mur]. + +A sinusoidal waveform is typically used as the excitation source at the antenna feed-point to perform the computations. The signal is allowed to propagate and interact with the objects modelled in the computational domain by means of numerical iterations. The FDTD algorithm iterates the field propagation in both space and time until the field conditions in the computational domain reach a sinusoidal steady state. The total field at selected tissue locations can be computed to determine the SAR. In order to maintain numerical stability for the computational algorithms, the Courant condition that provides the minimum relationship for selecting the time and spatial resolutions in the computation must be used. The iteration speed and expected computational errors are related to the parameters used for meeting the Courant condition. + +#### **I.2.2 MR/FDTD** + +The MR/FDTD algorithm [b-Johnson] overcomes computational inefficiencies of FDTD for geometries that include extensive sparse regions. In MR/FDTD the problem space is divided into several independent subregions distributed in an otherwise free space. The fields in the subregions are determined with the use of localized FDTD lattices. + +#### **I.2.3 Synthetic model** + +The synthetic model is used to calculate the electric field strength at an evaluation point using a vector sum of a number of small "patches" of the EUT antenna treated as separate sources [b-Altman]. The synthetic model can be used alone for free space exposure evaluation or together with the ray tracing algorithms to take into account the environment (e.g., ground, walls). + +This model is applicable in the radiating near-field and far-field regions. + +#### **I.2.4 Ray tracing** + +Ray tracing is useful for the evaluation of fields in large open areas and in urban environments that involve multiple scatterers. A simple two-ray model is used in [ITU-T K.52]. This model is accurate for open unbounded areas over a flat earth. More complex scattering environments that involve reflections from buildings, fluctuations in earth elevations, etc., require complicated multi-ray algorithms. The main disadvantage of ray tracing is that it is essentially a far-field technique. Also, it assumes that the size of the scatterer is large compared to the wavelength. Ray tracing is not suitable for calculation at long wavelengths, where diffraction is important. Ray tracing does not enable calculation of the SAR. + +#### **I.2.5 FDTD/ray tracing** + +The hybrid FDTD/ray tracing technique [b-Bernardi] tries to obtain the advantages of both methods. These methods use ray tracing to evaluate the incident field and FDTD to evaluate the SAR in the body. + +#### **I.2.6 MOM** + +The method of moments (MOM) [b-Harrington] is useful for evaluating the field strength emanating from antennas or other types of thin-wire conductive structures and for computation of the scattered field from thin-wire metallic structures. The use of MOM for computation of scattering from conductive planar surfaces requires that such surfaces be represented by a wire mesh. MOM is useful for near-field and far-field computations. The details of the antenna construction and geometry and the geometry of scattering objects must be known. The MOM is not useful for determining field penetration through dielectric bodies and, therefore, is not suitable for determining SAR. Commercial and non-commercial implementations of MOM are available. + +### **I.3 Other near-field models** + +The ray tracing algorithms are most useful for exposure sufficiently far from the radiator where the fields reflected from buildings and the unevenness of the terrain are important. In the majority of + +telecommunication applications, the field drops below the limit values a few metres from the source. Therefore, an accurate evaluation of the field near the antenna is required. In addition to MOM described in clause I.2.5, there exist several other methods to evaluate the field if the details of the antenna construction and geometry are known. Such methods can also take into account scattering from objects near the antenna. + +### **I.4 Practical problems** + +The main practical problem in the application of complex computational techniques, such as ray tracing or NEC is that the geometry needs to be specified precisely. In practice, the biggest obstacle to using even simple two-ray models is the lack of adequate information about the antenna and the exposure environment. For example, the available terrain data may have limited resolution. Another example is when the antenna pattern provided by the manufacturer is valid for the far-field region. Near the antenna, the antenna gain may decrease and lobes may shift. One solution for this is to calculate the antenna patterns using MOM if the antenna construction is known. + +# Appendix II + +## Identification and measurement of the main source of radiation + +(This appendix does not form an integral part of this Recommendation.) + +### II.1 Treatment of non-conformities – Exceeding the exposure limits + +The parameter that determines the compliance, or non-compliance, of a fixed telecommunication installation such as a base station is the level of cumulative exposure which can be measured with broadband or narrow-band meters (or probes) as defined in [IEC 62232]. + +In cases where, in a certain access zone, the level of cumulative exposure exceeds the maximum limit, the level of received energy of each radiant source should be measured using a narrow-band meter. It is necessary to highlight that when the level of cumulative exposure exceeds the limit (100%), it can be due to two reasons: + +- Existence of one or several radiating sources whose levels of received energy exceed the exposure limits corresponding to the operation frequency. +- The level of received energy of each of the involved radiating sources is lower than the exposure limit corresponding to its operation frequency; nevertheless, the combined effect of multiple sources contributes to the level of cumulative exposure being greater than 100%. + +Depending on the results of the measurements one of the following cases may apply. + +#### II.1.1 Case 1: Existence of one or several radiant sources whose levels of received energy exceeds the respective exposure limits + +By use of a narrow-band meter, it can be identified which radiant sources exceed the exposure limit corresponding to the operation frequency. Once identified, these should be adjusted using mitigation techniques. + +#### II.1.2 Case 2: The level of received energy of each of the radiant sources involved in the measurement is lower than the exposure limit corresponding to its operation frequency; nevertheless, the level of cumulative exposure is greater than 100% + +In this case, the level of cumulative exposure is greater than the limit (100%), even when the radiant sources, previously identified in the case 1, emit an electromagnetic field lower than their respective exposure limit. For this reason, it is necessary to select the sources that contribute the greatest energy, depending on the selection approach. Once identified, these should be adjusted using mitigation techniques. + +### II.2 Confirmation measurement + +Following the employment of the mitigation techniques, it should be verified that the level of cumulative exposure does not exceed 100%. + +# Bibliography + +- [b-Altman] Z. Altman, B. Begasse, C. Dale, A. Karwowski, J. Wiart, M.F. Wong, and L. Gattoufi (2002), *Efficient models for base station antennas for human exposure assessment*, IEEE Trans. Electromagn. Compat., Nov 2002, vol.44, pp. 588-592. +- [b-Bernardi] Bernardi P., Cavagnaro M., Pisa S., Piuizzi E. (2000), *Human Exposure to Radio Base-Station Antennas in Urban Environment*, IEEE Transactions on Microwave Theory and Techniques, Vol. 48, No. 11, pp. 1996-2002. +- [b-CSN EN 50413] CSN EN 50413 (2019), *Basic standard on measurement and calculation procedures for human exposure to electric, magnetic and electromagnetic fields (0 Hz - 300 GHz)*. +- [b-Harrington] Harrington R.F. (1993), *Field Computation by Moment Methods*, Wiley-IEEE Press. +- [b-ICNIRP] ICNIRP (2020), *ICNIRP guidelines for limiting exposure to electromagnetic fields (100 kHz to 300 GHz)*, Health Physics, 118(5), 2020, pp. 483-524. +- [b-IEC PAS 63446] IEC PAS 63446 (2022), *Conversion method of specific absorption rate to absorbed power density for the assessment of human exposure to radio frequency electromagnetic fields from wireless devices in close proximity to the head and body - Frequency range of 6 GHz to 10 GHz*. +- [b-IEC 60050 103] IEC 60050-103:2009, *International Electrotechnical Vocabulary (IEV) - Part 103: Mathematics – Functions*, Section 103-10-10. +- [b-IEC 60050 712] IEC 60050-712:1992, *International Electrotechnical Vocabulary (IEV) - Part 712: Antennas*, Sections 712-02-02 and 712-02-04. +- [b-JCGM 100:2008] JCGM 100 (2008), *Evaluation of measurement data – Guide to the expression of uncertainty in measurement*. +- [b-Johnson] Johnson J.M., Rahmat-Samii Y., (1997), *MR/FDTD: A multiple-region finite-difference – time-domain method*, Microwave and Optical Technology Letters, Vol. 14, No. 2, pp. 101-105. +- [b-Kunz] Kunz K.S., Luebbers R.J., (1993), *The Finite Difference Time Domain Method for Electromagnetics*, CRC Press. +- [b-Mur] Mur G., (1981), *Absorbing Boundary Conditions for the Finite-Difference Approximation of the time-Domain electromagnetic Field Equations*, IEEE Transactions on Electromagnetic Compatibility, Vol. EMC-23, No. 4, pp. 377-382. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph 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b/marked/K/T-REC-K.62-200402-I_PDF-E/raw.md @@ -0,0 +1,711 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a lightning bolt superimposed on it, and the letters 'ITU' written across the center. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.62** + +(02/2004) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**System level radiated emissions compliance +using mathematical modelling** + +ITU-T Recommendation K.62 + +--- + + + +# System level radiated emissions compliance using mathematical modelling + +## Summary + +This Recommendation supports telecommunication operators in demonstrating the compliance of the radiated emissions generated by telecommunication systems. + +Telecommunication operators typically construct their systems from many items of equipment that are each engineered to individually meet EMC requirements, including radiated emissions. This means that a system will typically contain a number of emissions sources (i.e., separate equipment items) at a number of common frequencies. This is true if the system contains many items of the same equipment or many items of different equipment. + +For such a system, the superposition of these multiple emissions has the potential to produce a system emission level that is greater than the system emission limit. This is of fundamental concern for telecommunication operators seeking to demonstrate the compliance of the radiated emissions of their systems. + +This Recommendation introduces a statistical approach to systems radiated emission compliance. By applying a statistical approach to the treatment of basic variables that are not known by the operator, a method is presented that allows the system emission level to be described statistically in terms of a probability and cumulative probability distributions. + +These distributions allow the compliance of the system emission level, with respect to a limit, to be expressed as a statistical confidence level (rather than as a simple "Pass" or "Fail" statement). It is proposed that the 80% confidence level be used for compliance to align with the approach taken for series production equipment within CISPR 22. + +The method presented may also be used by other organizations that either build or operate other systems that are formed from the integration of many items of digital electronic equipment that each individually comply with their own radiated emissions limit. + +## Source + +ITU-T Recommendation K.62 was approved on 29 February 2004 by ITU-T Study Group 5 (2001-2004) under the ITU-T Recommendation A.8 procedure. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +# INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2004 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +# CONTENTS + +| | Page | +|-----------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Terms and definitions ..... | 2 | +| 4 Abbreviations and acronyms ..... | 3 | +| 5 General principles..... | 3 | +| 6 Method..... | 5 | +| 6.1 System map ..... | 6 | +| 6.2 System composition..... | 7 | +| 6.3 Equipment emissions..... | 7 | +| 6.4 Common emissions frequencies ..... | 8 | +| 6.5 Evaluation points ..... | 8 | +| 6.6 Separation matrix..... | 8 | +| 6.7 Evaluation method..... | 8 | +| Appendix I – Example distributions ..... | 11 | +| I.1 N = 2 ..... | 11 | +| I.2 N = 3 ..... | 12 | +| I.3 N = 4 ..... | 13 | +| I.4 N = 5 ..... | 14 | +| I.5 N = 10 ..... | 15 | +| I.6 N = 100 ..... | 16 | +| I.7 Review of probability distributions ..... | 17 | + +# Introduction + +Telecommunication operators typically construct their systems from many items of equipment that are each engineered to individually meet EMC requirements, including radiated emissions. This means that a system will typically contain a number of emissions sources (i.e., separate equipment items) at a number of common frequencies. This is true if the system contains many items of the same equipment or many items of different equipment. + +The system as a whole will generally be expected to comply with a radiated emissions limit. This may be the same or different to the limit applicable to the individual constituent equipment. For each common emission frequency, the presence of many individual sources within the system means that the system emission level may be higher than that of the individual equipment. + +A method is presented that allows the radiated emissions to be assessed without performing practical measurement. The method presented is particularly suited to the analysis of systems that are physically very large, for which practical testing is both prohibitively expensive and practically difficult to perform. + +# **System level radiated emissions compliance using mathematical modelling** + +# **1 Scope** + +This Recommendation provides a procedure for demonstrating the compliance of the radiated RF emissions from telecommunication systems. + +Telecommunication operators typically construct their systems from many items of equipment that are each engineered to individually meet EMC requirements, including radiated emissions. This means that a system will typically contain a number of emissions sources (i.e., separate equipment items) at a number of common frequencies. This is true if the system contains many items of the same equipment or many items of different equipment. + +For such a system, the superposition of these multiple emissions has the potential to produce a system emission level that is greater than the system emission limit. This is of fundamental concern for telecommunication operators seeking to demonstrate the compliance of the radiated emissions of their systems. + +This Recommendation introduces a statistical approach to systems radiated emission compliance. By applying a statistical approach to the treatment of basic variables that are not known by the operator, a method is presented that allows the system emission level to be described statistically in terms of a probability and cumulative probability distributions. + +These distributions allow the compliance of the system emission level with respect to a limit to be expressed as a statistical confidence level (rather than as a simple "Pass" or "Fail" statement). It is proposed that the 80% confidence level be used for compliance to align with the approach taken for series production equipment within CISPR 22. + +The method presented may also be used by other organizations that either build or operate other systems that are formed from the integration of many items of digital electronic equipment that each individually comply with their own radiated emissions limit. + +This Recommendation does not define radiated emissions limits or methods of measurement for telecommunication systems. + +# **2 References** + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [1] CISPR 22 (1997), *Information technology equipment – Radio disturbance characteristics – Limits and method of measurement.* +- [2] ITU-R Recommendation P.525-2 (1994), *Calculation of free-space attenuation.* +- [3] ITU-R Recommendation P.526-8 (2003), *Propagation by diffraction.* + +# 3 Terms and definitions + +This Recommendation defines the following terms: + +**3.1 equipment:** Within this Recommendation, the term "equipment" applies to an item that forms a basic building block of a system. An equipment is generally supplied to the telecommunication operator by a third-party manufacturer and is placed on the market as a separate item. As a result, an equipment will have been engineered to meet local EMC requirements, including radiated emissions. + +**3.2 system:** Within this Recommendation, the term "system" applies to that item formed from the integration of many items of equipment, all at the same physical location, to deliver a defined function. All cables used to interconnect the constituent equipment that together form the system, are also part of the system. All interconnect cables that connect a system with other systems are not considered part of the system. + +**3.3 system emission level:** The emission level of the system, generated through the superposition of the emissions radiated at the common frequency by the system's constituent equipment. + +Within this Recommendation, this term is represented mathematically as $E_S$ . + +**3.4 probability distribution:** The probability distribution of an unknown, continuous variable, $x$ , that exists within the range $x_{min} \leq x \leq x_{max}$ is written as $p(x)$ . The probability distribution quantifies the probability (i.e., the relative frequency of occurrence) with which the variable will exist within the range $x$ and $x + dx$ . + +By definition, + +$$\int_{x_{min}}^{x_{max}} p(x)dx = 1$$ + +**3.5 cumulative probability distribution:** The cumulative probability distribution of an unknown, continuous variable, $x$ , that exists within the range $x_{min} \leq x \leq x_{max}$ is written as $CP(x)$ . The cumulative probability distribution quantifies the probability (i.e., the relative frequency of occurrence) with which the variable $x$ exists within the range: + +$$x_{min} \leq x \leq x'$$ + +where the value $x'$ falls within the range $x_{min} \leq x \leq x_{max}$ + +By definition, + +$$CP(x) = \int_{x_{min}}^{x'} p(x)dx$$ + +**3.6 compliance probability:** The probability (i.e., the relative frequency of occurrence) with which the system emission level, $E_S$ , will exist within the range: + +$$E_{Smin} \leq E_S \leq E_L$$ + +where: + +$E_{Smin}$ is the lower limit (i.e., minimum value) of the system emission level + +$E_L$ is the system emission limit + +The compliance probability is, therefore, the probability with which the system emission level will meet the system emission limit. + +The compliance probability is the cumulative probability value for $E_S = E_L$ , i.e., + +$$\text{compliance probability} = \int_{E_{Smin}}^{E_L} p(E_S) dE_S$$ + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations: + +| | | +|-----|-------------------------------------| +| CPD | Cumulative Probability Distribution | +| EMC | Electromagnetic Compatibility | +| ITE | Information Technology Equipment | +| PD | Probability Distribution | +| RF | Radio Frequency | + +# 5 General principles + +When a system contains a number of equipment items that individually emit at a common frequency, the superposition of these multiple emissions has the potential to produce a system emission level that is greater than the typical equipment emission level. This is a concern for telecommunication operators seeking to act responsibly and manage the EMC of their systems. + +If the individual equipment emission levels are known (at some known measurement distance) for each common emission frequency, mathematical tools do exist to predict the radiated emissions level of the system at this common frequency. + +Imagine that a number, $N$ , of radiated RF emissions at some common frequency, $f$ , are incident at some point of measurement. It is possible to represent each radiated emission at the point of measurement in the time-domain as a simple cosine function. The $i$ th radiated emission may be written as: + +$$E_i(t) = E_{0i} \cos(\alpha_i \pm \varpi t) \quad (1)$$ + +where: + +$E_i(t)$ is the instantaneous radiated emission level due to the $i$ th radiated emission at time, $t$ , at the point of measurement + +$E_{0i}$ is the amplitude of the $i$ th radiated emission at the point of measurement + +$\alpha_i$ is the phase difference between the $i$ th radiated emission and some agreed reference at the point of measurement + +$$\varpi = 2\pi f$$ + +The combination of these radiated emissions at the point of measurement can also be expressed as a simple cosine function at the same frequency, viz: + +$$E_0(t) = E_0 \cos(\alpha \pm \varpi t) \quad (2)$$ + +where: + +$E_0(t)$ is the instantaneous combined radiated emission level at time, $t$ , at the point of measurement + +$E_0$ is the amplitude of the combined radiated emission level + +$\alpha$ is the phase difference between the combined radiated emission level and some agreed reference at the point of measurement + +and + +$$E_0^2 = \sum_{i=1}^N E_{0i}^2 + 2 \sum_{j>i}^N \sum_{i=1}^N E_{0i} E_{0j} \cos(\alpha_i - \alpha_j) \quad (3)$$ + +Careful examination of this equation indicates that, to know the amplitude of the combined radiated emission level, $E_0$ , two pieces of information are required for each radiated emission: + +- the amplitude, $E_{0i}$ ; +- the phase, $\alpha_i$ , with respect to some reference. + +While the telecommunication operator can generally have knowledge of the amplitude, $E_{0i}$ , at the point of measurement, the operator cannot have knowledge of the phase value at the point of measurement. This means that the operator has only half the information required to use this equation. Hence, the conventional mathematical tools are not ideally suited to this problem. + +It is possible for the telecommunication operator to use the conventional mathematical tools to determine the upper limit to the system emission level. This is the system emission level produced when each individual equipment emission arrives at the point of measurement in phase. However, it is not recommended that the upper limit to the system emission level be considered in the compliance of the system's radiated RF emissions. + +In the absence of specific information, it is possible to assume that the phase value for each radiated emission is: + +- able to adopt any value within its physical range; and +- equally likely to do so. + +These are the two properties of a mathematically random variable. Hence, it is reasonable to assume that the phase value for each radiated emission is random. + +Examination of Equation (3) indicates that it is periodic in $2\pi$ , i.e., all unique values occur while the phase value is within the range $0 \leq \theta \leq 2\pi$ . This means that the phase term can no longer be described by a known, finite value. It is instead described by a PD, $p(\theta)$ . The mathematical properties of $\theta$ noted previously gives rise to the PD presented within Figure 1, this being known as either the random PD or the rectangular PD (due to its shape). + +![Figure 1/K.62 – The rectangular/random PD. The graph shows a rectangular probability density function P(theta) over the range theta_min = 0 to theta_max = 2pi. The horizontal axis is labeled theta and the vertical axis is labeled P(theta). A horizontal line represents the constant probability density, and a double-headed arrow indicates the range R_theta = 2pi.](91b7db8990b37ee7c7646b8df81bc199_img.jpg) + +The figure shows a plot of a probability density function $P(\theta)$ against $\theta$ . The horizontal axis ( $\theta$ ) has labels $\theta_{\min} = 0$ at the origin and $\theta_{\max} = 2\pi$ at the right end. The vertical axis is labeled $P(\theta)$ . A horizontal line segment is drawn at a constant height, representing a uniform probability density. A double-headed horizontal arrow spans the width of this line, labeled "Range, $R_\theta = 2\pi$ ". A small label "K.62\_F1" is located at the bottom right of the graph. + +Figure 1/K.62 – The rectangular/random PD. The graph shows a rectangular probability density function P(theta) over the range theta\_min = 0 to theta\_max = 2pi. The horizontal axis is labeled theta and the vertical axis is labeled P(theta). A horizontal line represents the constant probability density, and a double-headed arrow indicates the range R\_theta = 2pi. + +Figure 1/K.62 – The rectangular/random PD + +The value of $p(\theta)$ is found, from the definition of the random PD, to be: + +$$p(\theta) = \frac{1}{2\pi} \quad (4)$$ + +The use of a PD to represent the value of each phase term within Equation (3) allows the generation of the associated PD for the system emission level. + +Knowledge of the PD allows generation of the associated CPD of the system emission level. Where the upper limit to the system emission level exceeds the defined emission limit, the CPD may be used to quantify the compliance probability of the system with this limit. + +Appendix I presents examples of the PDs and CPDs that are generated through the use of this approach. The examples serve to illustrate the fact that the system emission level is, generally, highly unlikely to adopt its upper limit value. This is the reason for rejecting use of the upper limit to the system emission level in the compliance of the system's radiated RF emissions. The examples also serve to illustrate the fact that, generally, the system emission level is most likely to adopt some value that is lower than its upper limit value. + +The system is deemed to satisfy the defined emissions limit if the compliance probability with this limit is no less than 80%. This approach aligns with that taken within section 7.2 of [1]. + +# 6 Method + +This clause presents an overview of the method to be applied to assess the radiated emissions of a system. The method involves the execution of the process summarized within the flowchart presented as Figure 2. It is recommended that this flowchart be considered throughout consideration of this clause. + +![Flowchart of the Systems emission method (Figure 2/K.62). The process starts with 'START' and proceeds through generating system maps, compositions, and identifying emissions and frequencies. A loop for 'Current Frequency' (CF) involves applying corrections, calculating worst-case levels, and determining compliance probability if necessary. The loop continues until all frequencies are checked, then moves to 'Evaluation Points' (EP) until all are checked, ending at 'STOP'.](d4af765160d04ecef538e5066006dc77_img.jpg) + +``` + +graph TD + START([START]) --> S1[Generate the system map] + S1 --> S2[Generate the system composure] + S2 --> S3[Identify the equipment emissions] + S3 --> S4[Identify the common emission frequencies] + S4 --> S5[Determine the evaluation points] + S5 --> S6[Determine the separation matrix] + S6 --> S7[Counter, CF = 1 +Counter, EP = 1] + S7 --> A1((A)) + + A2((A)) --> S671[Apply propagation corrections] + S671 --> S672[Apply Boundary attenuation corrections] + S672 --> S673[Calculate worst-case emission level] + S673 --> D674{Upper limit level > limit level} + D674 -- Y --> S674[Determine compliance probability] + S674 --> S675 + D674 -- "N (Note 1)" --> S675[Increment CF] + S675 --> D675{CF > N_fc} + D675 -- Y --> S676[Increment EP Counter, CF = 1] + D675 -- N --> A3((A)) + S676 --> D677{EP > N_EP} + D677 -- Y --> STOP([STOP]) + D677 -- N --> A4((A)) + + style A1 fill:#fff,stroke:#000 + style A2 fill:#fff,stroke:#000 + style A3 fill:#fff,stroke:#000 + style A4 fill:#fff,stroke:#000 + +``` + +See 6.1 + +See 6.2 + +See 6.3 + +See 6.4 +Generate $N_{fc}$ + +See 6.5 +Generate $N_{EP}$ + +See 6.6 + +CF = Current Frequency +EP = Evaluation Point + +See 6.7.1 + +See 6.7.2 + +See 6.7.3 + +See 6.7.4 + +This Section considers the current common emission frequency at the current evaluation point + +See Note 1 + +See Note 2 + +See Note 3 + +K.62\_F2 + +Flowchart of the Systems emission method (Figure 2/K.62). The process starts with 'START' and proceeds through generating system maps, compositions, and identifying emissions and frequencies. A loop for 'Current Frequency' (CF) involves applying corrections, calculating worst-case levels, and determining compliance probability if necessary. The loop continues until all frequencies are checked, then moves to 'Evaluation Points' (EP) until all are checked, ending at 'STOP'. + +NOTE 1 – If upper limit < limit level, compliance probability is 100%. + +NOTE 2 – Repeat process at the next evaluation point, considering the next common emission frequency. + +NOTE 3 – Repeat process at next evaluation point, starting at the first common emission frequency. + +**Figure 2/K.62 – Systems emission method** + +## 6.1 System map + +A system map shall be generated. This is a simple scale diagram that presents the positions of the systems' constituent equipment and the system boundary. + +The system boundary is generally defined as the physical limit beyond which radiated emissions have the potential to degrade the reception of radio services. The system boundary is generally the boundary between a closed area that is controlled by an operator, and public space within which radio operators (not associated with the operator) are free to locate. The system boundary, therefore, arises from the nature of the system and its location. + +The system boundary may be: + +- A site fence: for systems installed within a site that is controlled by the operator; + +- A building wall: for systems installed within a building that is controlled by an operator but which has no additional surrounding land (typical of metropolitan buildings); +- Internal wall(s): for systems installed within multi-function buildings, within which the operator has control of a defined area, the rest of the building being shared with other users (typical of metropolitan areas). + +## 6.2 System composition + +A list of the equipment contained within the system shall be compiled. This list shall generally record: + +- the equipment's function; +- the equipment's name (as branded by the manufacturer); +- the equipment's manufacturer; +- the number of items of the equipment that exist within the system. + +## 6.3 Equipment emissions + +Information concerning the radiated emissions performance of the individual equipment is then compiled. Essentially, four items of information are required for each emission: + +- the frequency; +- the polarity (either horizontal or vertical); +- the level; +- the measurement distance. + +If EMC test reports are available for the equipment, these may allow identification of this information for the highest radiated emissions measured (these being below the emissions limit to which the equipment is engineered). + +If test reports are not available, it is possible to perform radiated emissions measurements of an equipment item to allow identification of the frequencies and the levels at which the highest radiated emissions were measured (these being below the emissions limit to which the equipment is engineered). + +In both cases, care must be taken during the compilation of this information to ensure that the equipment configuration during testing is as representative as possible to its installation within the system. Of particular concern are: + +- Housing: when under test, the equipment should have been located in the same racking/shelving practice as is to be used within the system; +- Cabling: when under test, the equipment configuration should have included the same interconnections as when installed within the system, with the same cable types and same signalling (simulated or exercised). +- Exercising: when under test, the equipment was exercised in a manner representative of its operation when deployed within the system (this being related to cabling, discussed previously). + +If test reports are not available and radiated emissions measurements are not to be performed on an equipment item, it is possible to make the default assumption: that the emissions of the equipment item are at the level of the emissions limit to which it has been engineered across the full frequency range. This default situation is very much an aggressive scenario, since telecommunication equipment does not generally emit at levels near to their emissions limit across the full frequency range covered by their limit: instead, equipment emissions are near to the limit for only a small percentage of the total frequency range covered by a limit. + +Each equipment item shall be assumed to radiate entirely isotropically at the frequencies and levels identified in this method. + +## **6.4 Common emissions frequencies** + +The information compiled during the 6.3 stage shall allow identification of the common emissions frequencies within the system: i.e., those frequencies at which two or more equipment items emit in the same polarity. + +This will allow the determination of the value of $N_{fc}$ – the number of common emissions frequencies within the system. + +For each common emissions frequency, the following information is to be compiled: + +- the frequency; +- the equipment emitting at this frequency; +- the polarity. + +## **6.5 Evaluation points** + +The system map, system composition and equipment emissions shall be examined to generate a set of evaluation points. Evaluation points are those positions on the system map and outside the system boundary at which the systems radiated emissions are to be evaluated. + +It is recommended that a number of evaluation points ( $N_{EP}$ ) be considered, i.e., system level emissions should not be considered at a single point. It is also recommended that the number of evaluation points increases as the physical size of the system under consideration increases. + +Factors to consider in the selection of evaluation points include: + +- known positions of existing radio users – these will require special attention; +- instances in which equipment items are located short distances from the system boundary (short meaning a distance less than or equal to the distance at which their emissions were measured); this is particularly true if these items have already been identified as having common emissions frequencies and individually emit at a relatively high level; +- locations adjacent to the system boundary with a high probability of radio deployment (such as high-density housing for systems located within urban areas, residential areas for systems located within suburban areas); +- publicly-accessible areas immediately adjacent to the system boundary (of particular interest in addressing the interference potential of the system to public mobile radio services, such as mobile telephony). + +## **6.6 Separation matrix** + +A separation matrix shall be compiled. This records the straight-line separation distance between each equipment item within the system and each evaluation point. + +## **6.7 Evaluation method** + +For each selected evaluation point and identified common emission frequency, the systems radiated emissions shall be determined using the following procedure. + +### **6.7.1 Correction I: Propagation** + +The system map shall be consulted to determine the propagation path between each item of equipment and each evaluation point. + +The propagation paths vary in complexity. Examples include (in order of increasing complexity): + +- i) Blocked path: there exists no simple, straight-line propagation path between the equipment and the evaluation point – some conducting structure standing between the equipment and the evaluation point essentially screens the equipment emissions. +- ii) Direct path: there exists a simple, straight-line propagation path between the equipment item and the evaluation point that is free of conducting structures that may reflect, diffract or block the propagation of the equipment emissions to the evaluation point. This straight line may cross a number of boundaries requiring consideration (see 6.7.2). +- iii) Indirect reflected path: there exists an indirect path between the equipment item and the evaluation point that involves at least one reflection of the equipment's emissions by an adjacent conducting structure. +- iv) Indirect diffracted path: there exists an indirect path between the equipment item and the evaluation point that involves the diffraction of the equipment's emissions by an adjacent conducting structure. +- v) Complex path: there exists a propagation path between the equipment item and the evaluation point that involves one or more instances of one or more of the previously discussed elementary paths. + +As the complexity of the propagation path increases, the reduction in the level (i.e., the propagation attenuation) of the equipment emissions that arrive at the evaluation point also increases. Hence, it is possible to perform several iterations of study in which progressively more complex propagation paths are included. The first such iteration would consider the blocked and direct paths only. The second may consider the blocked, the direct and the first order reflected paths (i.e., a reflected path that contains a single reflection). The third iteration may consider the blocked, the direct and the first and second order reflected paths. + +It is necessary to adjust the equipment emissions levels identified within 6.3 to account for the propagation path between the equipment item and the evaluation point. + +The adjustment can consider any radio propagation model that is felt to apply given the emission frequency and propagation path under consideration. Two examples are provided in [2] and [3]. + +As a minimum, in the absence of a known and validated radio propagation model, simple far-field free-space propagation may be assumed. This involves use of the following propagation equation: + +$$E_0(d_2) = E_0(d_1) - 20 \log_{10} \left\{ \frac{d_2}{d_1} \right\} \quad (5)$$ + +where: + +$d_1$ is the separation distance in metres between the equipment and the measurement antenna during the radiated emissions measurement + +$d_2$ is the separation distance in metres between the equipment and the evaluation point + +$E_0(d_1)$ is the amplitude of the equipment emission (expressed in logarithmic units) when measured at distance $d_1$ + +$E_0(d_2)$ is the amplitude of the equipment emission (expressed in logarithmic units) predicted at distance $d_2$ due to propagation between distance $d_1$ and $d_2$ + +The value of $d_2$ is found for each equipment item emitting at the common frequency from the separation matrix. + +### 6.7.2 Correction II: Boundary attenuation + +When the propagation path between the equipment item and the evaluation point passes through one or more physical boundaries (a wall, a chain-link fence etc.), the equipment emissions levels identified within 6.3 may be corrected by the associated boundary attenuation values, if these are known. + +If these values are unknown, the operator may use "typical" values derived from previous experience. + +It is also possible to assume no boundary attenuation. This will have the effect of increasing the system emissions level. + +### 6.7.3 Assessment I: Highest system level emission + +Having completed the steps described within clauses 6.1 through 6.7.2, the corrected equipment emissions levels are available at the current evaluation point. + +For each emission frequency of interest, the upper limit to the system emission level is calculated. This is performed using the following equation: + +$$E_{MAX} = \sum_{i=1}^N E_{0i} \quad (6)$$ + +where: + +$N$ is the number of different equipment items within the system emitting at the common frequency and polarity of interest + +$E_{0i}$ is the adjusted amplitude (i.e., the amplitude at the evaluation point expressed in linear units) of the emissions of the $i$ th equipment type at the common frequency of interest + +$E_{MAX}$ is the upper limit to the system emissions level (expressed in linear units) at the common emissions frequency of interest + +The upper limit to the system emission level is compared with the system emission limit. + +If the upper limit to the system emission level is equal to or below the system emission limit, the system emissions clearly comply with this limit for the frequency and polarity of interest. If this is true, no further action needs to be taken for the current common emissions frequency at the current evaluation point. + +If, however, the upper limit to the system emission level exceeds the system emission limit, it is necessary to continue to the next step, documented in 6.7.4. + +### 6.7.4 Assessment II: Monte Carlo analysis + +If the upper limit to the system emission level returned by Equation (6) exceeds the system emission limit, Monte Carlo simulation techniques may be applied to Equation (3) to numerically generate the PD and CPD that describe the system emission level. + +The CPD is used to obtain the compliance probability of the system emission level with the system emission limit. + +If the compliance probability is greater than or equal to 80%, the system emissions are deemed to comply with the system emission limit for the frequency and polarity of interest. + +If the compliance probability is less than 80%, the telecommunication operator is recommended to first review the level of detail considered within the assessment performed. + +If the assessment considered that all equipment items emit at their limit level across the full frequency range of the limit (as discussed in 6.3), it is recommended that the analysis be repeated to identify the common frequencies and the emissions details of the equipment that emit at these frequencies. + +If the assessment considered only the minimum propagation correction (as discussed in 6.7.1), it is recommended that the analysis be repeated with more accurate propagation corrections considered. + +If the assessment considered no boundary attenuation values (as discussed in 6.7.2), despite there being physical boundaries for the system under consideration, it is recommended that the analysis be repeated with these boundary attenuation values included. + +If the compliance probability remains below 80% after these factors have been accounted for within the analysis, only then it is recommended that the telecommunication operator seeks to reduce the system emission level in such a way that the compliance probability of at least 80% is achieved. The use of Monte Carlo simulation techniques allows the impact of many possible changes to be investigated. It is recommended that the most convenient change to the system be implemented. + +# Appendix I + +## Example distributions + +This appendix presents and discusses some examples of the PDs and CPDs generated upon the application of the method presented within this Recommendation. + +### I.1 N = 2 + +When the system contains two items that emit at a common frequency, the PD and CPD display a characteristic form. Examples are displayed in Figures I.1 and I.2 for the case of common emissions amplitudes (in this case $E_1 = E_2 = 40 \text{ dB}\mu\text{V/m}$ ). + +Examination of Figures I.1 and I.2 indicates that the amplitude of the system emission level in this case occurs between the upper limit of $(40 \text{ dB}\mu\text{V/m} + 20 \log_{10}\{2\})$ 46 $\text{dB}\mu\text{V/m}$ and a lower limit of zero. + +Figure I.1 indicates that the PD displays a clear maximum at the worst-case field level: the worst-case system-level amplitude is, therefore, the most likely to occur. + +![Figure I.1/K.62 – Example PD for N = 2. A line graph showing Probability [x 1e-03] on the y-axis (0 to 100) versus E Field [dBμV/m] on the x-axis (5 to 50). The curve shows a sharp peak at approximately 46 dBμV/m, reaching a probability of about 90. The x-axis is labeled 'E Field [dBμV/m]' and 'K.62_F1.1'.](a3ee9a6f9fa9251ee0cac2d16e67e620_img.jpg) + +The figure is a line graph representing a Probability Distribution (PD) for a system with two items (N=2). The y-axis is labeled 'Probability [x 1e-03]' and ranges from 0 to 100 in increments of 10. The x-axis is labeled 'E Field [dBμV/m]' and ranges from 5 to 50 in increments of 5. The graph shows a curve that is relatively flat and low (around 10) for E Field values from 5 to 40 dBμV/m. There are some minor fluctuations between 20 and 40 dBμV/m. At approximately 45 dBμV/m, the curve begins to rise sharply, reaching a peak of about 90 at 46 dBμV/m. After the peak, the curve drops sharply back towards zero. A label 'K.62\_F1.1' is present in the bottom right corner of the plot area. + +Figure I.1/K.62 – Example PD for N = 2. A line graph showing Probability [x 1e-03] on the y-axis (0 to 100) versus E Field [dBμV/m] on the x-axis (5 to 50). The curve shows a sharp peak at approximately 46 dBμV/m, reaching a probability of about 90. The x-axis is labeled 'E Field [dBμV/m]' and 'K.62\_F1.1'. + +Figure I.1/K.62 – Example PD for N = 2 + +![Figure I.2/K.62: Example CPD for N = 2. A line graph showing cumulative probability on the y-axis (0.00 to 1.00) versus E Field [dBμV/m] on the x-axis (5 to 50). The curve starts near 0 at 5 dBμV/m and rises steeply, reaching 1.00 at approximately 46 dBμV/m. The label 'K.62_FI.2' is in the bottom right corner.](b53846f262c6904a1b45abef2e95fbd8_img.jpg) + +Figure I.2/K.62: Example CPD for N = 2. A line graph showing cumulative probability on the y-axis (0.00 to 1.00) versus E Field [dBμV/m] on the x-axis (5 to 50). The curve starts near 0 at 5 dBμV/m and rises steeply, reaching 1.00 at approximately 46 dBμV/m. The label 'K.62\_FI.2' is in the bottom right corner. + +**Figure I.2/K.62 – Example CPD for N = 2** + +### I.2 N = 3 + +When the system contains three items that emit at a common frequency, the PD and CPD also display a distinct form. Examples are displayed in Figures I.3 and I.4 for the case of common emissions amplitudes (in this case $E_1 = E_2 = E_3 = 40 \text{ dB}\mu\text{V/m}$ ). + +Examination of Figures I.3 and I.4 indicates that the amplitude of the system emission level in this case occurs between the upper limit of $(40 \text{ dB}\mu\text{V/m} + 20 \log_{10}\{3\})$ 49 dBμV/m and the lower limit of zero. + +Figure I.3 indicates that the PD displays a clear maximum at the common emissions amplitude, i.e., when $E_S = E_1$ . This means that the amplitude of the composite system that is most likely to occur is the common amplitude of the constituent equipment: i.e., that the telecommunication operator is most likely to measure no change in the emissions amplitude when moving from one equipment item to three equipment items. + +![Figure I.3/K.62: Example PD for N = 3. A line graph showing Probability [x 1e-03] on the y-axis (0 to 30) versus E Field [dBμV/m] on the x-axis (5 to 50). The curve shows a sharp peak at 40 dBμV/m, reaching a probability of approximately 28. The label 'K.62_FI.3' is in the bottom right corner.](595e9fd7e96f6b95bbaa6e6a45c32682_img.jpg) + +Figure I.3/K.62: Example PD for N = 3. A line graph showing Probability [x 1e-03] on the y-axis (0 to 30) versus E Field [dBμV/m] on the x-axis (5 to 50). The curve shows a sharp peak at 40 dBμV/m, reaching a probability of approximately 28. The label 'K.62\_FI.3' is in the bottom right corner. + +**Figure I.3/K.62 – Example PD for N = 3** + +![Figure I.4/K.62 – Example CPD for N = 3. A graph showing Cumulative probability (Y-axis, 0.00 to 1.00) versus E Field [dBμV/m] (X-axis, 5 to 50). The curve starts at 0.00 at 5 dBμV/m and rises steeply between 35 and 50 dBμV/m, reaching 1.00 at approximately 48 dBμV/m. The label K.62_FI.4 is in the bottom right corner.](b2d16e07bfa79d67a8adabf7e26c7764_img.jpg) + +Figure I.4/K.62 – Example CPD for N = 3. A graph showing Cumulative probability (Y-axis, 0.00 to 1.00) versus E Field [dBμV/m] (X-axis, 5 to 50). The curve starts at 0.00 at 5 dBμV/m and rises steeply between 35 and 50 dBμV/m, reaching 1.00 at approximately 48 dBμV/m. The label K.62\_FI.4 is in the bottom right corner. + +**Figure I.4/K.62 – Example CPD for N = 3** + +### I.3 N = 4 + +When the system contains four items that emit at a common frequency, the PD and CPD display a characteristic form. Examples are displayed in Figures I.5 and I.6 for the case of common emissions amplitudes (in this case $E_1 = E_2 = E_3 = E_4 = 40 \text{ dB}\mu\text{V/m}$ ). + +Examination of Figures I.5 and I.6 indicates that the amplitude of the system emission level in this case occurs between the upper limit of $(40 \text{ dB}\mu\text{V/m} + 20 \log_{10}\{4\})$ 52 dBμV/m and a lower limit of zero. + +Figure I.5 indicates that the PD displays a maxima at the system emissions amplitude of ~46 dBμV/m. This is noted to be some 6 dB below the upper limit level. + +![Figure I.5/K.62 – Example PD for N = 4. A graph showing Probability [x 1e-03] (Y-axis, 0 to 20) versus E Field [dBμV/m] (X-axis, 10 to 55). The curve rises from 10 dBμV/m, peaks at approximately 19.5 at 46 dBμV/m, and then drops sharply to near zero by 52 dBμV/m. The label K.62_FI.5 is in the bottom right corner.](3e0c2bf6c51c575d096c7fc95c1e8454_img.jpg) + +Figure I.5/K.62 – Example PD for N = 4. A graph showing Probability [x 1e-03] (Y-axis, 0 to 20) versus E Field [dBμV/m] (X-axis, 10 to 55). The curve rises from 10 dBμV/m, peaks at approximately 19.5 at 46 dBμV/m, and then drops sharply to near zero by 52 dBμV/m. The label K.62\_FI.5 is in the bottom right corner. + +**Figure I.5/K.62 – Example PD for N = 4** + +![Figure I.6/K.62: Example CPD for N = 4. This is a line graph showing the Cumulative Probability on the y-axis (ranging from 0.00 to 1.00 in increments of 0.10) against the E Field [dBμV/m] on the x-axis (ranging from 10 to 55 in increments of 5). The curve starts near zero at 10 dBμV/m, remains very low until about 30 dBμV/m, then rises sharply in an S-curve shape, passing through 0.50 at approximately 45 dBμV/m and reaching 1.00 at approximately 52 dBμV/m. The identifier K.62_FI.6 is in the bottom right.](3102c32204f998dba666e1e915d5babf_img.jpg) + +Figure I.6/K.62: Example CPD for N = 4. This is a line graph showing the Cumulative Probability on the y-axis (ranging from 0.00 to 1.00 in increments of 0.10) against the E Field [dBμV/m] on the x-axis (ranging from 10 to 55 in increments of 5). The curve starts near zero at 10 dBμV/m, remains very low until about 30 dBμV/m, then rises sharply in an S-curve shape, passing through 0.50 at approximately 45 dBμV/m and reaching 1.00 at approximately 52 dBμV/m. The identifier K.62\_FI.6 is in the bottom right. + +**Figure I.6/K.62 – Example CPD for N = 4** + +### I.4 N = 5 + +When the system contains five items that emit at a common frequency, the PD and CPD display a characteristic form. Examples are displayed in Figures I.7 and I.8 for the case of common emissions amplitudes (in this case $E_1 = E_2 = E_3 = E_4 = E_5 = 40 \text{ dB}\mu\text{V/m}$ ). + +Examination of Figures I.7 and I.8 indicates that the amplitude of the system emission level in this case occurs between the upper limit of $(40 \text{ dB}\mu\text{V/m} + 20 \log_{10}\{5\})$ 53.97 dBμV/m and a lower limit of zero. + +Figure I.7 indicates that the PD displays a maxima at a system emission level of ~45 dBμV/m. This is noted to be some ~9 dB below the worst-case value. + +![Figure I.7/K.62: Example PD for N = 5. This is a line graph showing Probability [x 1e-03] on the y-axis (ranging from 0 to 20 in increments of 2) against the E Field [dBμV/m] on the x-axis (ranging from 10 to 55 in increments of 5). The curve shows a probability density function that starts near zero at 10 dBμV/m, increases steadily with some minor fluctuations, reaches a peak (maxima) of approximately 18.5 at 45 dBμV/m, and then drops sharply to zero by 54 dBμV/m. The identifier K.62_FI.7 is in the bottom right.](ca80b99f7e1d6e6b854f22190f2e14d8_img.jpg) + +Figure I.7/K.62: Example PD for N = 5. This is a line graph showing Probability [x 1e-03] on the y-axis (ranging from 0 to 20 in increments of 2) against the E Field [dBμV/m] on the x-axis (ranging from 10 to 55 in increments of 5). The curve shows a probability density function that starts near zero at 10 dBμV/m, increases steadily with some minor fluctuations, reaches a peak (maxima) of approximately 18.5 at 45 dBμV/m, and then drops sharply to zero by 54 dBμV/m. The identifier K.62\_FI.7 is in the bottom right. + +**Figure I.7/K.62 – Example PD for N = 5** + +![Figure I.8/K.62: Example CPD for N = 5. A graph showing Cumulative probability (Y-axis, 0.00 to 1.00 in increments of 0.10) versus E Field [dBμV/m] (X-axis, 10 to 55 in increments of 5). The curve is an S-shaped cumulative distribution function starting at 0 around 25 dBμV/m, passing through 0.50 at approximately 46 dBμV/m, and reaching 1.00 at 55 dBμV/m. The grid is composed of 10 horizontal lines and 9 vertical lines. The label K.62_FI.8 is in the bottom right corner.](5ed9189841659dfb01f809b8e3b21f74_img.jpg) + +Figure I.8/K.62: Example CPD for N = 5. A graph showing Cumulative probability (Y-axis, 0.00 to 1.00 in increments of 0.10) versus E Field [dBμV/m] (X-axis, 10 to 55 in increments of 5). The curve is an S-shaped cumulative distribution function starting at 0 around 25 dBμV/m, passing through 0.50 at approximately 46 dBμV/m, and reaching 1.00 at 55 dBμV/m. The grid is composed of 10 horizontal lines and 9 vertical lines. The label K.62\_FI.8 is in the bottom right corner. + +**Figure I.8/K.62 – Example CPD for N = 5** + +### I.5 N = 10 + +When the system contains ten items that emit at a common frequency, the PD and CPD display a characteristic form. Examples are displayed in Figures I.9 and I.10 for the case of common emissions amplitudes (in this case 40 dBμV/m). + +Examination of Figures I.9 and I.10 indicates that the amplitude of the system emission level in this case occurs between the upper limit of $(40 \text{ dB}\mu\text{V/m} + 20 \log_{10}\{10\})$ 60 dBμV/m and a lower limit of zero. + +Figure I.9 indicates that the PD displays a maxima at a system emission level of ~48 dBμV/m. This is noted to be some 12 dB below the worst-case value. + +![Figure I.9/K.62: Example PD for N = 10. A graph showing Probability [x 1e-03] (Y-axis, 0 to 28 in increments of 2) versus E Field [dBμV/m] (X-axis, 20 to 60 in increments of 5). The curve is a bell-shaped probability density function starting near 0 at 20 dBμV/m, rising to a peak of approximately 26.5 at 48 dBμV/m, and falling back to 0 at 60 dBμV/m. The grid is composed of 14 horizontal lines and 8 vertical lines. The label K.62_FI.9 is in the bottom right corner.](bd4617f25d15430eb78c2d6d75a99dde_img.jpg) + +Figure I.9/K.62: Example PD for N = 10. A graph showing Probability [x 1e-03] (Y-axis, 0 to 28 in increments of 2) versus E Field [dBμV/m] (X-axis, 20 to 60 in increments of 5). The curve is a bell-shaped probability density function starting near 0 at 20 dBμV/m, rising to a peak of approximately 26.5 at 48 dBμV/m, and falling back to 0 at 60 dBμV/m. The grid is composed of 14 horizontal lines and 8 vertical lines. The label K.62\_FI.9 is in the bottom right corner. + +**Figure I.9/K.62 – Example PD for N = 10** + +![Figure I.10/K.62 – Example CPD for N = 10. A graph showing Cumulative probability (Y-axis, 0.00 to 1.00) versus E Field [dBμV/m] (X-axis, 20 to 60). The curve is S-shaped, starting near 0 at 20 dBμV/m and reaching 1.00 at approximately 55 dBμV/m.](60e9207be66a64332619bb4b667fe67b_img.jpg) + +This graph shows the cumulative probability (CPD) for a system with N=10. The x-axis represents the E Field in dBμV/m, ranging from 20 to 60. The y-axis represents the cumulative probability, ranging from 0.00 to 1.00. The curve starts at approximately 0.00 at 20 dBμV/m, rises steeply between 35 and 55 dBμV/m, and reaches 1.00 at about 55 dBμV/m. + +Figure I.10/K.62 – Example CPD for N = 10. A graph showing Cumulative probability (Y-axis, 0.00 to 1.00) versus E Field [dBμV/m] (X-axis, 20 to 60). The curve is S-shaped, starting near 0 at 20 dBμV/m and reaching 1.00 at approximately 55 dBμV/m. + +**Figure I.10/K.62 – Example CPD for N = 10** + +### I.6 N = 100 + +When the system contains one hundred items that emit at a common frequency, the PD and CPD display a characteristic form. Examples are displayed in Figures I.11 and I.12 for the case of common emissions amplitudes (in this case 40 dBμV/m). + +Examination of Figures I.11 and I.12 indicates that the amplitude of the system emission level in this case occurs between the upper limit of $(40 \text{ dB}\mu\text{V/m} + 20 \log_{10}\{100\})$ 80 dBμV/m and a lower limit of zero. + +Figure I.11 indicates that the PD displays a maxima at a system emissions amplitude of ~58 dBμV/m. This is noted to be some 22 dB below the worst-case value. + +![Figure I.11/K.62 – Example PD for N=100. A graph showing Probability [x 1e-03] (Y-axis, 0 to 90) versus E Field [dBμV/m] (X-axis, 35 to 80). The curve is bell-shaped, peaking at approximately 85 at 58 dBμV/m.](f630450865788387c4821c6d5760c850_img.jpg) + +This graph shows the probability density (PD) for a system with N=100. The x-axis represents the E Field in dBμV/m, ranging from 35 to 80. The y-axis represents the probability in units of 10-3, ranging from 0 to 90. The curve is bell-shaped, starting at approximately 10 at 40 dBμV/m, peaking at about 85 at 58 dBμV/m, and returning to near zero at 70 dBμV/m. + +Figure I.11/K.62 – Example PD for N=100. A graph showing Probability [x 1e-03] (Y-axis, 0 to 90) versus E Field [dBμV/m] (X-axis, 35 to 80). The curve is bell-shaped, peaking at approximately 85 at 58 dBμV/m. + +**Figure I.11/K.62 – Example PD for N=100** + +![Figure I.12/K.62 – Example CPD for N=100. A graph showing Cumulative probability (Y-axis, 0.00 to 1.00) versus E Field [dBμV/m] (X-axis, 35 to 80). The curve is S-shaped, starting near 0.00 at 40 dBμV/m and reaching 1.00 at 65 dBμV/m. The curve is labeled K.62_F1.12.](0f79a59f3766fc341ff688a23692c1d9_img.jpg) + +| E Field [dBμV/m] | Cumulative probability | +|------------------|------------------------| +| 40 | 0.00 | +| 45 | 0.02 | +| 50 | 0.08 | +| 55 | 0.25 | +| 60 | 0.60 | +| 65 | 1.00 | +| 70 | 1.00 | +| 75 | 1.00 | +| 80 | 1.00 | + +Figure I.12/K.62 – Example CPD for N=100. A graph showing Cumulative probability (Y-axis, 0.00 to 1.00) versus E Field [dBμV/m] (X-axis, 35 to 80). The curve is S-shaped, starting near 0.00 at 40 dBμV/m and reaching 1.00 at 65 dBμV/m. The curve is labeled K.62\_F1.12. + +**Figure I.12/K.62 – Example CPD for N=100** + +### I.7 Review of probability distributions + +Review of the PD plots presented in the previous examples indicates a pattern: as the number of independent emissions at a common frequency increases, the likelihood of the upper limit level occurring decreases. + +For example: + +- When only two radiated field terms are being added, the PD reaches its maxima when the system emission level approaches the worst case. +- When ten radiated field terms are being added, the PD reaches a minima when the systems emissions amplitude approaches the worst case. For the example displayed, the worst-case amplitude is 60 dBμV/m, but the PD approaches zero values above 58 dBμV/m. +- When one hundred radiated field terms are being added, the PD reaches a minima when the systems emissions amplitude approaches the worst case. For the example displayed, the worst-case amplitude is 80 dBμV/m, but the PD approaches zero values above ~70 dBμV/m. + +Hence, the worst-case amplitude is extremely unlikely to occur and, hence, should not be used as the basis of system compliance. + +Also, as the number of independent emissions at a common frequency increases, the margin between the system emission level that is most likely to occur, and the upper limit to the system emission level, increases. + +For example: + +- When only two radiated field terms are being added, the PD reaches its maxima when the system emissions amplitude approaches the worst case. Hence, the margin between the most likely and worst-case levels is 0 dB. +- When ten radiated field terms are being added, the PD reaches a maxima at ~48 dBμV/m while the upper limit is 60 dBμV/m. Hence, the margin between the most likely and upper limit is ~12 dBμV. +- When one hundred radiated field terms are being added, the PD reaches a maxima at ~58 dBμV/m while the upper limit is 80 dBμV/m. Hence, the margin between the most likely and upper limit is ~22 dBμV. + +An intuitive explanation for this behaviour exists. The upper limit to the system emission level is associated with a single, specific combination of events: when *all* of the radiated field terms arrive at the evaluation point in-phase with one another. As more radiated field terms are added, the probability of this singular event occurring becomes progressively smaller. For other lower emissions amplitudes, there are generally many different combinations of phase values (i.e., many different events) among the radiated field terms that generate the amplitudes. Hence, the probability of these amplitudes occurring is higher. + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure, Internet protocol aspects and Next Generation Networks | +| Series Z | Languages and general software aspects for telecommunication 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striking it, symbolizing telecommunications. The letters "ITU" are prominently displayed in blue and red. + +ITU logo + +International +Telecommunication +Union + + + +# Recommendation ITU-T K.64 + +## Safe working practices for outside equipment installed in particular environments + +# Summary + +Recommendation ITU-T K.64 describes working practices for service personnel to help them work safely in telecommunication installations in three specific environments. + +The specific environments covered in this Recommendation are characterized by wet conditions or close proximity to exposed metallic parts. + +The working practices apply to telecommunication plants with voltage levels higher than the limits defined for analogue PSTN circuits, such as remote feeding telecommunication current or voltage (RFT-C or RFT-V) circuits. + +This version of Recommendation ITU-T K.64 includes a warning regarding contact with terminals carrying RFT circuits with small parts of the body, e.g., back of the hand. The references have been updated to include the IEC 62368 series. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.64 | 2004-02-29 | 5 | 11.1002/1000/7147 | +| 2.0 | ITU-T K.64 | 2011-01-13 | 5 | 11.1002/1000/11035 | +| 3.0 | ITU-T K.64 | 2016-06-29 | 5 | 11.1002/1000/12874 | +| 4.0 | ITU-T K.64 | 2020-06-29 | 5 | 11.1002/1000/14294 | + +## Keywords + +ITU-T K.50, IEC 60950, IEC 62368, RFT, RFT-C, RFT-V, safe, TNV, work practices. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2020 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|-----|---------------------------------------------------------------------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 3.1 | Terms defined elsewhere ..... | 1 | +| 3.2 | Terms defined in this Recommendation..... | 1 | +| 4 | Abbreviations and acronyms ..... | 3 | +| 5 | Conventions ..... | 3 | +| 6 | Telecommunication particular workplaces..... | 3 | +| 7 | Voltage levels on TLC installations ..... | 4 | +| 8 | Work practices on TLC plants in particular environments..... | 5 | +| 8.1 | Switching off the power supply..... | 5 | +| 8.2 | Practices to be used when working on live telecommunication circuits ..... | 6 | +| 9 | Work on telecommunication installations at risk of electric shock..... | 7 | +| 9.1 | Work on equipment or devices (terminal box, etc.) ..... | 7 | +| 9.2 | Work on cables ..... | 8 | +| | Appendix I – Rationale of safe voltage limit values for workplace at major risk of electric shock ..... | 10 | +| I.1 | Operating cases..... | 10 | +| I.2 | Calculation assumption ..... | 10 | +| I.3 | Limit current calculation ..... | 12 | +| I.4 | Voltage limit calculation ..... | 15 | +| | Appendix II – Cross reference table of IEC 60950 and IEC 62368 terms..... | 18 | +| | Bibliography..... | 23 | + +# Introduction + +Network operators, in their telecommunication infrastructure, use equipment that is remotely powered by symmetrical or coaxial pair cables. The voltages and currents that power these systems differ among them and comply with the limit values defined in [IEC 60950-1], [[IEC 60950-21], and [IEC 62368] series for symmetrical pair cables and in [IEC 60728-11] for coaxial cables. The limits in these standards have been defined to allow service personnel to work safely on these lines without de-energizing the circuits. + +Nevertheless, there are telecommunication environments that necessitate additional precautions to enable service personnel to work safely on circuits that are usually considered safe to touch. These environments are characterized as wet conditions, sometimes associated with standing water. This Recommendation lists three practical situations where additional precautions are needed and defines how the service personnel should perform work to reduce risk associated with these situations. + +Specific applications, local conditions or regulations may give rise to a need for additional safeguards or modifications to practices presented in this Recommendation. + +# Recommendation ITU-T K.64 + +## Safe working practices for outside equipment installed in particular environments + +# 1 Scope + +The scope of this Recommendation is to provide working procedures for maintenance activities in specific environments for telecommunication plants with voltage levels higher than the limits defined for analogue public switched telephone network (PSTN) circuits. The specific environments covered in this Recommendation are characterized by wet conditions or close proximity to exposed metallic parts. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.50] Recommendation ITU-T K.50 (2018), *Safe limits for operating voltages and currents for telecommunication systems powered over the network*. +- [IEC 60479-1] IEC 60479-1 Ed. 4.0 :2018, *Effects of current on human beings and livestock – Part 1: General aspects*. +- [IEC 60728-11] IEC 60728-11: Ed. 3.0: 2016, *Cable networks for television signals, sound signals and interactive services – Part 11: Safety*. +- [IEC 60950-1] IEC 60950-1: Ed. 2.0: 2005, *Information technology equipment – Safety – Part 1: General requirements*. +- [IEC 60950-21] IEC 60950-21: Ed. 1.0: 2002, *Information technology equipment – Safety – Part 21: Remote power feeding*. +- [IEC 62368-1] IEC 62368-1: 2018, *Audio/video, information and communication technology equipment – Part 1: Safety requirements*. +- [IEC 62368-3] IEC 62368-3: 2017, *Audio/video, information and communication technology equipment – Part 3: Safety aspects for DC power transfer through communication cables and ports*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +None. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 analogue public switched telephone network (PSTN) circuit:** A telecommunication network voltage (TNV) circuit (see clause 3.2.9) operating at voltages less than or equal to 90 V d.c. with cadenced ringing signals complying with [IEC 60950-1]. + +**3.2.2 cable TV (CATV) circuit:** An interface circuit for a cable distribution system intended for transmission of video, data and/or audio signals between separate buildings or between outdoor antennas and buildings. + +NOTE – CATV circuits remotely powered, i.e., circuits on feeder between the optical node unit and the last line amplifier, are only considered in this Recommendation. + +**3.2.3 dry conditions:** An environmental condition in which the resistance of the skin and to the body is not reduced with respect to the value defined in [IEC 60479-1]. + +**3.2.4 environment classification:** The environments considered by this Recommendation are classified as follows: + +- Environment type 1: environment with the floor in wet conditions, sometimes with standing water (for example, manholes, vaults, trenches); +- Environment type 2: environment with wet walls and confined working space (for example, vaults) such that the wet wall may be in contact with the person's body and producing (in the case of hand contact with an energized part) a current path different to the hand-to-feet current path; +- Environment type 3: environment with confined working space and existing extraneous metallic parts (for example, facilities of other services); during the operations, large areas of the metallic parts (e.g., metallic tower for radio link) are in continuous contact with the body. + +**3.2.5 insulated tool:** A tool, such as a screwdriver, scissor, or pliers, having an insulated handle that may be used by service personnel during his operations on telecommunication equipment or cable. + +**3.2.6 RFT-C circuit:** A remote feeding telecommunication circuit that is so designed and protected that under normal operating conditions and single fault conditions, the currents in the circuit do not exceed defined values. + +NOTE – The current limit values under normal operating and single fault conditions are specified in [ITU-T K.50] or [IEC 60950-21] or [IEC 62368-3]. + +**3.2.7 RFT-V circuit:** A remote feeding telecommunication circuit that is so designed and protected that under normal operating conditions and single fault conditions, the voltages are limited and the accessible area of contact is limited. + +NOTE – The voltage limit values under normal operating and single fault conditions are specified in [ITU-T K.50] or [IEC 60950-21] or [IEC 62368-3]. + +**3.2.8 service personnel:** A person having appropriate technical training and experience necessary to be aware of hazards, to which that person may be exposed in performing a task, and of measures to minimize the risks to that person or other persons. + +**3.2.9 telecommunication network voltage (TNV) circuit:** A circuit in the equipment to which the accessible area of contact is limited and that is so designed and protected that, under normal operating conditions and single fault conditions, the voltages do not exceed specified limit values. + +**3.2.10 user:** Any person other than service personnel. + +**3.2.11 vault:** An underground chamber (manhole, pit, exchange or high rise building cable entry) or above ground pedestal or cabinet used to accommodate communication equipment such as joint closures, housings and/or electronic equipment installed in the external plant environment. + +**3.2.12 wet condition:** An environmental condition in which the resistance of the skin and to the body is reduced with respect to the value defined in [IEC 60479-1]. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|----------------------------------------------------| +| AC | Alternating Current | +| CATV | Cable TV | +| CCP | Cross-Connection Point | +| ES | Energy Source | +| ES1 | Energy Source class 1 | +| ES2 | Energy Source class 2 | +| MDF | Main Distribution Frame | +| PSTN | Public Switched Telephone Network | +| RFT-C | Remote Feeding Telecommunication – Current circuit | +| RFT-V | Remote Feeding Telecommunication – Voltage circuit | +| RMS | Root Mean Square | +| SELV | Safety Extra Low Voltage | +| TLC | Telecommunication | +| TNV | Telecommunication Network Voltage | +| DC | Direct Current | + +# 5 Conventions + +None. + +# 6 Telecommunication particular workplaces + +Safety standards recognize that voltage levels defined as safe to touch in normal conditions may present a hazard to service personnel in damp conditions. For example, it is recognized that even safety extra low voltage (SELV) circuit limits may present a risk of electric shock for a person when such circuits are used in a wet environment. For this reason, the voltage limit for parts touchable by a person is equal to half the value of the limit applicable in dry environments. + +Obviously, it is not possible to reduce the voltages usually present on a telecommunication line in order to have the same safe conditions within a wet environment when contacted by service personnel. In such cases, recognizing the presence of potentially harmful energy sources, the behaviour of service personnel becomes an effective means to prevent injury. Therefore, there is the need to follow safe working practices when equipment maintenance is necessary and a dry environment is not possible. This approach is possible because the service personnel are skilled and trained. + +An example of such work is the maintenance activities inside a manhole or, in general, in a vault where the presence of water at the bottom is as likely as that of infiltration water on the internal walls. Sometimes, the confined space of the workplace hinders the maintenance of the equipment and increases the likelihood that the current path through the person's body will differ from the hand-to-feet current path. Lastly, service personnel may accidentally make an adverse, large-area contact with energized conductors. This could happen, for instance, if one hand holds a tool fastened to the energized conductor while the other hand, or another body part, is in full contact with an earthed conductor. + +Summarizing, there are three particular environments that may present safety hazards to the service personnel that operates a telecommunication (TLC) plant: + +- 1) Environment type 1: wet conditions (see clause 3.2.4); +- 2) Environment type 2: confined working space in wet conditions (see clause 3.2.4); +- 3) Environment type 3: confined working space contacting extraneous metallic parts (see clause 3.2.4). + +To reduce the risk of electric shock associated with the maintenance activities performed in such an environment, service personnel shall follow simple and effective working practices, as described in clause 8. + +# 7 Voltage levels on TLC installations + +[IEC 60950-1] allows voltage levels, not higher than 70.7 V (peak) or 120 V d.c., on symmetrical pair cables of telecommunication networks type TNV-2 and TNV-3. These TNV circuits, accessible to skilled personnel only, are safe for an ordinary environment (dry conditions) but in wet conditions the contact with TNV circuits at voltages greater than analogue PSTN voltages (see clause 3.2.1) may be dangerous for service personnel due to a reduction of the contact impedance. + +[IEC 62368-1] has energy sources (ESs) with maximum DC operating voltages equivalent to TNV levels. ES1 limits are DC 60 V at DC 2 mA and 70 V rms at 0.5 mA rms. ES2 limits are DC 120 V at DC 25 mA and 140 V rms at 5 mA rms. + +The voltage levels used in a coaxial cable distribution network are defined in [IEC 60728-11]. Voltage levels between the inner and outer conductor of up to 65 V rms, 120 V d.c. are allowed. It must be considered that such voltage levels shall be completely inaccessible to the user and service personnel may access these voltages only after removing, with a tool, the equipment cover. + +[IEC 60950-21] has introduced remote feeding telecommunication circuits limited in current (RFT-C) or in voltage (RFT-V). Both circuits are suitable for barehanded contact by service personnel in powered state, in line with [ITU-T K.50]. [IEC 62368-3] also incorporates RFT-V and RFT-C limits. + +Table 1 summarizes the voltage levels that may be present on a telecommunication line under normal conditions for different types of circuits in the network [IEC 60950-1], [ITU-T K.50], [IEC 60728-11], [IEC 60950-21], [IEC 62368-1] and [IEC 62368-3]. These voltage levels are based on the assumption that the surface contact area is not greater than 1 cm2 in order to limit body impedance in the hand-to-feet path to more than 5 k $\Omega$ . + +**Table 1 – Voltages on TLC lines in normal conditions for different types of circuits in the equipment powering the network** + +| Type of circuit | V d.c. max [V] | V a.c. max [V] | +|-----------------|--------------------|-------------------| +| TNV | 120 (ES2) | 70.7 (peak value) | +| RFT-C | $\pm 400$ (Note 1) | N.A. | +| RFT-V | $\pm 140$ (Note 2) | N.A. | +| CATV | 120 | 65 (rms) | + +NOTE 1 – This value applies if the voltage rating of the wiring of the telecommunication network is not specified. If it is specified, the supply voltage shall be limited to this value or to a maximum value of 1500 V (see [ITU-T K.50]). + +NOTE 2 – Or $\pm 200$ V if the short circuit current is limited to 10 mA d.c. (see [ITU-T K.50]). + +Essentially, the current flowing through the body determines human responses to electrical stimuli. Voltage is important because, together with the body impedance, it determines the current through the body. + +The previous voltage and current limits have been calculated using the 'let-go' limit. This defines the threshold at which inability to release the energized conductor occurs. In the case of limited voltage circuits, e.g., TNV and RFT-V circuits, the voltage limits have been defined using a body impedance of 5 k $\Omega$ . This introduces a margin of safety into the limit in case a current path through a body is created because higher values of body impedance may be encountered in practice, as indicated by [IEC TS 60479-1] (small contact surface area). + +Working practices performed on live conductors affect the likelihood that a possible physiological response may occur. The likelihood of specific response of the body occurring at a specific voltage level depends on the precautions adopted whilst working on those live parts. These precautions may be very simple for lower voltages but can include the disconnection of the power feeding on the cable or on the equipment before working. + +The safety precautions described below allow service personnel to work safely in the specific environments defined in this Recommendation. + +NOTE – The possible effects of induced voltages on telecommunication lines are under study. + +# **8 Work practices on TLC plants in particular environments** + +Work on telecommunication installations under normal conditions as well as in the specific environments considered in this Recommendation (Environment types 1, 2 or 3) shall only be performed by skilled service personnel following well-defined safe working procedures. + +This Recommendation requires, first of all, the classification of the telecommunication installation where it is necessary to work; practically the installations with voltages from TNV, RFT-C, RFT-V or coaxial cable circuits have to be indicated. Prior to starting work, this Recommendation requires that service personnel assess the risk by determining the voltage classification in the telecommunication facilities (e.g., by consulting records/maps (plans) of the TLC facilities in which information on the type of service is reported). + +For conductors with voltages higher than that of the analogue PSTN service, labels or insulated markers (e.g., coloured plastic collets) should be installed at the main distribution frame (MDF) and at accessible cross-connection points (CCPs) along the route to clearly indicate both the service and the voltage. In these cases, the safety precautions described in clauses 8.1 and 8.2 (Figure 1) shall be followed. + +## **8.1 Switching off the power supply** + +Electrical works on TLC installations in environment types 1, 2 or 3 should be performed, preferentially, with the power supply switched off or by using insulating or disconnect or shorting devices at the MDF and other suitable CCPs, on the conductors carrying the potentially hazardous voltage levels that fall within the scope of this Recommendation. + +Where practicable, a temporary notice should also be placed at the MDF clearly indicating the necessity to leave in place the insulating or disconnect devices or not to change the switch position due to works in progress on the line. + +Nevertheless, the warning shall be considered sufficient only if the disabling devices are used in places where the access is limited to service personnel; otherwise, it is required to lock the disabling devices in their "Off" position. + +Once the work has been completed, the power supply may be reconnected only after the service personnel have made the installation safe. + +At the MDF, those conductors carrying voltage levels from RFT-V or RFT-C circuits should be labelled. Unintentional contact between conductors from different power feeding circuits, even of the same type, should be avoided, e.g., by providing insulating shielding covers. + +Prior to the commencement of work, service personnel are required to verify, through use of an appropriate measuring instrument, the absence of voltages exceeding analogue PSTN limits (see clause 3.2.1) on all conductors where it is necessary to operate. + +## **8.2 Practices to be used when working on live telecommunication circuits** + +Where it is not practicable to disconnect the power feed to those parts that may be touched barehanded by service personnel under the specified environment, tools with insulated handles or other effective insulated protection devices (e.g., insulated gloves and/or rubber boots in type 1 environment) should be used. + +For the different environment types defined in this Recommendation, it is necessary to adopt the following safety precautions1: + +- Environment type 1: if voltages on TNV or RFT-V circuits with no current limitation are higher than 105 V d.c., it is necessary to use insulated connectors or tools with insulated handles to avoid bare hand contact with conductors, and/or rubber insulating boots to prevent moisture contact with the feet/legs. +- Environment types 2 and 3: if voltages on TNV or RFT-V circuits with no current limitation are higher than 90 V d.c., it is necessary to use insulated connectors or tools with insulated handles, insulated boots or insulated gloves. +Environment types 2 and 3: if voltages on coaxial cables are higher than 60 V rms, it is necessary to use insulated connectors or tools with insulated handles. + +When work is performed on live parts, it is essential that possible earth faults or leakage currents (see [ITU-T K.50]), in particular with floating power systems that may originate dangerous touch currents (RFT-C circuits), be detected by measurement, and that the low impedance to earth fault of the one line conductor be removed before beginning work. + +These safety precautions for live working on different types of environment are summarized in Table 2. + +When working close to other telecommunication live parts different from PSTN circuits, if service personnel is unable to use special protection devices, the worker should be careful to maintain his hands sufficiently far away from those live parts. + +Particular care should be taken when working on, or near, terminals carrying RFT circuits. If terminals carrying an RFT circuit are bridged to a small part of the body, e.g., back of the hand or a finger, a higher than normal current can occur, resulting in a painful shock and a burn at the contact points. This higher than normal current is due to the lower resistance between the contact points, compared to a hand-to-hand contact. + +--- + +1 The values indicated are calculated in Appendix I. + +**Table 2 – Safety precautions for live working in different types of environment** + +| Environment | TNV circuit | RFT-C circuit | RFT-V circuit with no current limitation | CATV circuit | +|----------------------------------------------------------------------------------|----------------------------------------------------------------|------------------------------------------------------------------|-------------------------------------------------------------------------------------------|---------------------------------------------------------------------------| +| Environment type 1: wet conditions. | If above 105 V d.c., use insulated connectors or tool handles. | Touch only one conductor and check for earth faults on the line. | If above 105 V d.c., use insulated connectors or tool handles. | No specific precautions given. | +| Environment type 2: confined working space in wet conditions. | If above 90 V d.c., use insulated connectors or tool handles. | Touch only one conductor and check for earth faults on the line. | If above 90 V d.c., use insulated connectors or tool handles, insulated gloves, or boots. | If voltages are above 60 V rms, use insulated connectors or tool handles. | +| Environment type 3: confined working space contacting extraneous metallic parts. | If above 90 V d.c., use insulated connectors or tool handles. | Touch only one conductor and check for earth faults on the line. | If above 90 V d.c., use insulated connectors or tool handles, insulated gloves, or boots. | If voltages are above 60 V rms, use insulated connectors or tool handles. | + +![Flowchart for safety procedures in particular environments. It starts with 'Telecommunication electrical work', branching into 'Circuit depowered' and 'Circuit powered'. 'Circuit depowered' leads to 'Disconnection and secure against reconnection'. 'Circuit powered' leads to 'Table 2 conditions apply', which then leads to 'Tools with insulated handle or personal protection device'. Brackets on the left label the branches as 'Live parts' and 'Safety precautions'.](eefe19c5e14dc4d6c316b7f7fbb7d7d7_img.jpg) + +``` + +graph TD + A[Telecommunication electrical work] --> B[Circuit depowered] + A --> C[Circuit powered] + B --> D[Disconnection and secure against reconnection] + C --> E[Table 2 conditions apply] + E --> F[Tools with insulated handle or personal protection device] + +``` + +K.64(20)\_F01 + +Flowchart for safety procedures in particular environments. It starts with 'Telecommunication electrical work', branching into 'Circuit depowered' and 'Circuit powered'. 'Circuit depowered' leads to 'Disconnection and secure against reconnection'. 'Circuit powered' leads to 'Table 2 conditions apply', which then leads to 'Tools with insulated handle or personal protection device'. Brackets on the left label the branches as 'Live parts' and 'Safety precautions'. + +**Figure 1 – Scheme for safety procedures in particular environments (see clause 3.4)** + +# 9 Work on telecommunication installations at risk of electric shock + +Usually, work performed on a telecommunication plant may consist of one of the following activities: + +- maintenance or replacement of equipment; +- operations on cables. + +NOTE – This Recommendation is concerned only with the above two points because it is considered that prior to the plant's first activation, it is switched off and so is not dangerous in the sense given in this Recommendation. + +## 9.1 Work on equipment or devices (terminal box, etc.) + +Equipment installed in environments at risk of electric shock shall have a warning mark clearly visible on its enclosure to remind service personnel of the need to use the appropriate safety procedures. + +In an environment like a manhole, installation and siting of equipment should take into account the need to perform maintenance activities. Where possible, consideration should also be given in the installation and siting of equipment to allow ease of operations in the workplace. One example of this is the use of cables long enough to allow equipment within the manhole to be either: + +- temporarily removed from the manhole entirely and placed on the road surface; +- raised from the floor of the manhole to a level at which maintenance may be performed from the outside. + +Unless the road surface is wet, the operation in these conditions is comparable to that performed in an ordinary environment. + +When it is necessary to operate in an environment such as a vault, then, considering the likely limited freedom of movement, the working procedure must be subordinated to the nature of the operation. + +For such a purpose, as far as maintenance activities on line or terminal equipment are concerned, it is possible to distinguish the following cases: + +- 1) Electrical measurements: it is required that the measurement instruments and their accessories have an insulation level adequate to the expected voltages present on the telecommunication line. +- 2) Maintenance by removal or insertion of components directly extractable. +- 3) Maintenance with action by hand directly on components without accessible parts at dangerous voltages. +- 4) Maintenance with action by hand on components having accessible parts at dangerous voltages. + +Only when the operation should be performed on accessible parts of live equipment is it necessary to use tools with insulated handle. In other cases, service personnel will not experience harmful effects and so bare hand operation is possible. + +Replacement of equipment shall be performed only after the power supply has been switched off. + +## 9.2 Work on cables + +Generally, work on a cable can be safely carried out if the cable sheath is not open or, after its opening, it is not possible to touch the internal conductors with remote power feeding voltages higher than analogue PSTN limits. + +The external conductor of a coaxial cable or the plastic insulation of pair cable conductors shall not be damaged during the work. + +During normal activities performed on cables, e.g., splice making, contact may occur with the entire span of the hand or even hand to hand. Such possibilities shall be avoided. Therefore, splicing techniques that do not remove the insulation of the conductors are preferred. + +Two kinds of splicing are possible on cables: + +- 1) making a new splice involving all the conductors of the cable; +- 2) remaking a splice involving some conductors of the cable. + +The first case may occur, e.g., when a cable has been cut in the field, and since the telephone service is down, it may be convenient to disconnect the power supply on all conductors with voltage levels higher than analogue limits (PSTN services) to protect service personnel making the splice in an environment at risk of electric shock. + +In the second case, two methods may be used: + +- 1) identify the pairs in the splice with voltages exceeding analogue PSTN limits using instruments like "pair-finders" or by traditional methods that require service personnel to proceed by trial and error, contacting the conductors one by one in order to identify them at the exchange on the network side. Label them to avoid unwanted contacts. This may be the easiest method with paper insulated conductors; + +- 2) use insulated tools to avoid conductive paths to earth. This may be the most practicable method for plastic insulated conductors. + +The conductors with voltage levels higher than the analogue limits (PSTN services) shall be interrupted at the MDF/CCP with suitable insulators/disconnectors or shorting devices unless splicing is performed without the likelihood of skin contact with bare conductors by using suitable personal protective devices and practices described in clause 8.2. + +As for equipment, the service personnel shall ensure, first of all, that cable conductors are not powered. Operation on the cable prior to verification that the power remote feeding has been switched off shall be performed using insulated tools. + +# Appendix I + +## Rationale of safe voltage limit values for workplace at major risk of electric shock + +(This appendix does not form an integral part of this Recommendation.) + +This appendix describes the rationale leading to the safe voltage limit values shown in Table 2 for human safety while operating on TNV, RFT-V and CATV circuits in a workplace at major risk of electric shock. + +The calculations are done according to [IEC 60479-1] determining voltage and current values that, in the case of human body contact with active parts of a telecommunication plant, do not generate dangerous situations for trained personnel. + +### I.1 Operating cases + +With reference to the environment type classification for electric shock risk, defined in clause 3.2.4, different operating conditions, which could determine different effects on the human body, have been identified. + +They depend substantially on the type of contact of the body with the telecommunication plant and the ground, and the site's environmental conditions. + +The body parts which can come into contact with the telecommunication plant and the ground are: + +- hands; +- back; +- seat; +- feet. + +### I.2 Calculation assumption + +Calculations have to determine the contact voltage limit originated by touching the telecommunication plant that, based on the human body impedance value in the contact path ( $Z$ ), generates no dangerous current for people. + +For this, refer to [IEC 60479-1], which considers this impedance $Z$ constituted by: + +$$Z = Z_b + Z_c$$ + +where: + +$Z_b$ is a partition of human body impedance, function of surface contact and touch voltage, developing through the current path considered; + +$Z_c$ is the touch ground impedance. + +Figure I.1 shows the human body impedance, function of surface contact and touch voltage $Z_T$ , through the hand-to-hand path. + +To obtain the $Z_b$ value, it is necessary to calculate the human body impedance partition, in the path interested by the contact, with respect to such impedance $Z_T$ . + +Such partition can be obtained by using Figure I.2. + +![Figure I.1: Human body impedance for hand-to-hand path. A log-linear graph showing Total body impedance Z_T [kΩ] on the y-axis (0.1 to 10,000) versus Touch voltage U_T [V] on the x-axis (0 to 225). Five curves (A-E) represent different surface contact areas. Curve E is the highest, followed by D, C, B, and A. A shaded region at the top right indicates skin breakdown at 220 V.](1d529a819ad929684331c55eed6673bb_img.jpg) + +| Curve | Surface contact area | +|-------|-----------------------| +| A | 8 000 mm 2 | +| B | 1 000 mm 2 | +| C | 100 mm 2 | +| D | 10 mm 2 | +| E | 1 mm 2 | + +(Breakdown of the skin at 220 V) + +K.64(20)\_FI.1 + +Figure I.1: Human body impedance for hand-to-hand path. A log-linear graph showing Total body impedance Z\_T [kΩ] on the y-axis (0.1 to 10,000) versus Touch voltage U\_T [V] on the x-axis (0 to 225). Five curves (A-E) represent different surface contact areas. Curve E is the highest, followed by D, C, B, and A. A shaded region at the top right indicates skin breakdown at 220 V. + +**Figure I.1 – Human body impedance for hand-to-hand path** + +![Figure I.2: Percentage of the human body internal impedance in relation to the hand-to-foot path. A diagram of a human figure showing the percentage contribution of various body parts to the total internal impedance. The percentages are: Head (10.0), Neck (6.1), Shoulders (10.9), Upper arms (9.9), Torso (1.3), Thighs (5.1), Knees (8.7), Lower legs (14.1), and Feet (32.3).](f4d72193f77f6646a2a1f4baaa927154_img.jpg) + +K.64(20)\_FI.2 + +Figure I.2: Percentage of the human body internal impedance in relation to the hand-to-foot path. A diagram of a human figure showing the percentage contribution of various body parts to the total internal impedance. The percentages are: Head (10.0), Neck (6.1), Shoulders (10.9), Upper arms (9.9), Torso (1.3), Thighs (5.1), Knees (8.7), Lower legs (14.1), and Feet (32.3). + +**Figure I.2 – Percentage of the human body internal impedance in relation to the hand-to-foot path** + +The numbers indicate the percentage of the internal impedance of the human body for the part of the body concerned, in relation to the hand-to-foot path. + +NOTE 1 – In order to calculate the total body impedance $Z_T$ for a given current path, the internal impedances for all parts of the body of the current path have to be added as well as the impedances of the skin of the contact areas. + +NOTE 2 – The internal impedance from one hand to both feet is approximately 75%, the impedance from both hands to both feet 50% and the impedance from both hands to the trunk of the body 25% of the impedance hand-to-hand or hand-to-foot. + +Therefore: + +$$Z_b = k \times Z_T$$ + +where $k$ is the sum of percentages met in the considered path. + +Although, according to [IEC 60950-1], the surface contact to be considered is 100 mm2 (fingertip dimension), this calculation should take into consideration the possibility that the operator, while using insulated tools, accidentally touches active telecommunication parts with the whole finger. Therefore, this surface is assumed to be 1 000 mm2, and consequently curve B of Figure I.1 should be taken into account. + +Regarding body impedance contact with ground $Z_c$ , it is assumed that: + +- floor and walls are always wet or damped and their impedance is assumed no greater than 200 $\Omega$ ; +- the impedance of wet or damp shoes is 1 000 $\Omega$ [b-CENELEC HD 637]; +- metallic parts impedance is assumed to be 0 $\Omega$ . + +Therefore, cases to be analysed are those shown in Table I.1, considering negligible the difference between back and seat path (1.3%). + +**Table I.1 – Analysis cases** + +| Case | Environment type | Contact path | Condition of shoes | Impedance contact with floor, wall or metallic parts | % impedance of human body with respect to the path [K] | +|------|------------------|--------------|--------------------|------------------------------------------------------|--------------------------------------------------------| +| 1 | 1 | hand-feet | wet or damp | 1 200 $\Omega$ | 75 | +| 2 | | hands-feet | | | 50 | +| 3 | | hand-foot | | | 100 | +| 4 | 2 | hand-hand | | 200 $\Omega$ | 100 | +| 5 | | hand-seat | | | 50 | +| 6 | | hands-seat | | | 25 | +| 7 | 3 | hand-hand | | 0 $\Omega$ | 100 | +| 8 | | hand-seat | | | 50 | +| 9 | | hands-seat | | | 25 | + +### I.3 Limit current calculation + +The level of danger of current flowing through the human body is related to its intensity and its duration. + +Figure I.3 shows the zone limits for different physiological effects for the human body and their description related to alternating current. + +Figure I.4 shows the zone limits for different physiological effects for the human body and their description related to direct current. + +Such current values can change depending on the different current paths through the human body; the factor taking into account this fact is the so-called "heart-current factor", $F$ , whose value is specified in Table I.2. + +Therefore: + +$$I_h = \frac{I_{ref}}{F}$$ + +where: + +$I_{ref}$ is the reference current in Figures I.3 and I.4 + +$I_h$ is the current for different paths indicated in Table I.2 + +In case of similar paths, the most precautionary $F$ value has to be considered. + +Table I.3 shows the limit values for a.c. and d.c. with respect to the "b" curve. + +Table I.4 shows the limit values for a.c. and d.c. with respect to the "c1" curve. + +![Log-log graph showing physiological effects of AC current. Y-axis: Duration t [ms] (10-10,000). X-axis: Body current I_B [mA] (0.1-10,000). Line 'a' is vertical at 0.5 mA. Line 'b' is vertical at 10 mA for t > 2000ms, then curves left to 200 mA at t = 10ms. Curves c1, c2, c3 start near 40-50 mA and curve right as time decreases. Zones AC-1, AC-2, AC-3, and AC-4 (subdivided into 4.1, 4.2, 4.3) are defined by these boundaries.](b2d16e07bfa79d67a8adabf7e26c7764_img.jpg) + +Log-log graph showing physiological effects of AC current. Y-axis: Duration t [ms] (10-10,000). X-axis: Body current I\_B [mA] (0.1-10,000). Line 'a' is vertical at 0.5 mA. Line 'b' is vertical at 10 mA for t > 2000ms, then curves left to 200 mA at t = 10ms. Curves c1, c2, c3 start near 40-50 mA and curve right as time decreases. Zones AC-1, AC-2, AC-3, and AC-4 (subdivided into 4.1, 4.2, 4.3) are defined by these boundaries. + +| Zone descriptions | | | +|------------------------------------------------------------------------------------------------------------------------------------|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Zone designation | Zone limits | Physiological effects | +| AC-1 | Up to 0.5 mA line a | Usually no reaction. | +| AC-2 | 0.5 mA up to line b (Note) | Usually no harmful physiological effects. | +| AC-3 | Line b up to curve $c_1$ | Usually no organic damage to be expected. Likelihood of cramp like muscular contractions and difficulty in breathing for durations of current-flow longer than 2 s. Reversible disturbances of formation and conduction of impulses in the heart, including a trial fibrillation and transient cardiac arrest without ventricular fibrillation increasing with current magnitude and time. | +| AC-4 | Above curve $c_1$ | Increasing with magnitude and time, dangerous pathophysiological effects such as cardiac arrest, breathing arrest and severe burns may occur in addition to the effects of zone 3. | +| AC-4.1 | $c_1 - c_2$ | Probability of ventricular fibrillation increasing up to about 5%. | +| AC-4.2 | $c_2 - c_3$ | Probability of ventricular fibrillation up to about 50%. | +| AC-4.3 | Beyond curve $c_3$ | Probability of ventricular fibrillation above 50%. | +| NOTE – For durations of current-flow below 10 ms, the limit for the body current for line b remains constant at a value of 200 mA. | | | + +**Figure I.3 – Physiological effects of alternating current on human body** + +![Log-log graph showing the physiological effects of direct current. The y-axis is 'Duration of current flow t [ms]' ranging from 10 to 10,000. The x-axis is 'Body current I_B [mA]' ranging from 0.1 to 10,000. Vertical line 'a' is at 2 mA. Line 'b' starts at 200 mA for t < 10 ms and curves leftward as t increases. Curves c1, c2, and c3 define sub-zones within DC-4. Zones are labeled DC-1 (left of line a), DC-2 (between a and b), DC-3 (between b and c1), and DC-4 (right of c1). DC-4 is further divided into DC-4.1, DC-4.2, and DC-4.3 by curves c1, c2, and c3.](3102c32204f998dba666e1e915d5babf_img.jpg) + +Log-log graph showing the physiological effects of direct current. The y-axis is 'Duration of current flow t [ms]' ranging from 10 to 10,000. The x-axis is 'Body current I\_B [mA]' ranging from 0.1 to 10,000. Vertical line 'a' is at 2 mA. Line 'b' starts at 200 mA for t < 10 ms and curves leftward as t increases. Curves c1, c2, and c3 define sub-zones within DC-4. Zones are labeled DC-1 (left of line a), DC-2 (between a and b), DC-3 (between b and c1), and DC-4 (right of c1). DC-4 is further divided into DC-4.1, DC-4.2, and DC-4.3 by curves c1, c2, and c3. + +**Zone descriptions** + +| Zone designation | Zone limits | Physiological effects | +|------------------|--------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| DC-1 | Up to 2 mA line a | Usually no reaction. Slight pricking pain when switching on or off. | +| DC-2 | 2 mA up to line b (Note) | Usually no harmful physiological effects. | +| DC-3 | Line b up to curve $c_1$ | Usually no organic damage to be expected. Increasing with current magnitude and time, reversible disturbances of formation and conduction of impulses in the heart may occur. | +| DC-4 | Above curve $c_1$ | Increasing with current magnitude and time, dangerous pathophysiological effects for example, severe burns, are to be expected in addition to the effects of zone 3. | +| DC-4.1 | $c_1 - c_2$ | Probability of ventricular fibrillation increasing up to about 5%. | +| DC-4.2 | $c_2 - c_3$ | Probability of ventricular fibrillation up to about 50%. | +| DC-4.3 | Beyond curve $c_3$ | Probability of ventricular fibrillation above 50%. | + +NOTE – For durations of current-flow below 10 ms, the limit for the body current for line b remains constant at a value of 200 mA. + +**Figure I.4 – Physiological effects of direct current on human body** + +**Table I.2 – Heart-current factor** + +| Current path | Heart-current factor $F$ | +|-----------------------------------------------------|--------------------------| +| Left hand to left foot, right foot or both feet | 1.0 | +| Both hands to both feet | 1.0 | +| Left hand to right hand | 0.4 | +| Right hand to left foot, right foot or to both feet | 0.8 | +| Back to right hand | 0.3 | +| Back to left hand | 0.7 | +| Chest to right hand | 1.3 | +| Chest to left hand | 1.5 | +| Seat to left hand, right hand or to both hands | 0.7 | + +**Table I.3 – a.c. and d.c. limit values with respect to curve b** + +| Case | Environment type | Path contact | Condition of shoes | Impedance contact with floor, wall or metallic parts [ $\Omega$ ] | % impedance of human body with respect to the path [k] | Heart-current factor F | Current reference a.c. for 'b' curve [mA] | Limit current a.c. for 'b' curve [mA] | Current reference d.c. for 'b' curve [mA] | Limit current d.c. for 'b' curve [mA] | | +|------|------------------|--------------|--------------------|-------------------------------------------------------------------|--------------------------------------------------------|------------------------|-------------------------------------------|---------------------------------------|-------------------------------------------|---------------------------------------|--| +| 1 | 1 | hand-feet | wet or damp | 1200 | 75 | 1.0 | 10.0 | 10.00 | 30.0 | 30.00 | | +| 2 | | hands-feet | | | 50 | | | | | | | +| 3 | | hand-foot | | | 100 | | | | | | | +| 4 | 2 | hand-hand | | 200 | 100 | 0.4 | | 25.00 | | 75.00 | | +| 5 | | hand-seat | | | 50 | 0.7 | | 14.29 | | 42.86 | | +| 6 | | hands-seat | | | 25 | | | 14.29 | | 42.86 | | +| 7 | 3 | hand-hand | | 0 | 100 | 0.4 | | 25.00 | | 75.00 | | +| 8 | | hand-seat | | | 50 | 0.7 | | 14.29 | | 42.86 | | +| 9 | | hands-seat | | | 25 | | | 14.29 | | 42.86 | | + +**Table I.4 – a.c. and d.c. limit values with respect to curve c1** + +| Case | Environment type | Path contact | Condition of shoes | Impedance contact with floor, wall or metallic parts [ $\Omega$ ] | % impedance of human body with respect to the path [k] | Heart-current factor F | Current reference a.c. for c 1 curve [mA] | Limit current a.c. for c 1 curve [mA] | Current reference d.c. for c 1 curve [mA] | Limit current d.c. for c 1 curve [mA] | | +|------|------------------|--------------|--------------------|-------------------------------------------------------------------|--------------------------------------------------------|------------------------|------------------------------------------------------|--------------------------------------------------|------------------------------------------------------|--------------------------------------------------|--| +| 1 | 1 | hand-feet | wet or damp | 1 200 | 75 | 1.0 | 40.0 | 40.00 | 150.0 | 150.00 | | +| 2 | | hands-feet | | | 50 | | | | | | | +| 3 | | hand-foot | | | 100 | | | | | | | +| 4 | 2 | hand-hand | | 200 | 100 | 0.4 | | 100.00 | | 375.00 | | +| 5 | | hand-seat | | | 50 | 0.7 | | 57.14 | | 214.29 | | +| 6 | | hands-seat | | | 25 | | | 57.14 | | 214.29 | | +| 7 | 3 | hand-hand | | 0 | 100 | 0.4 | | 100.00 | | 375.00 | | +| 8 | | hand-seat | | | 50 | 0.7 | | 57.14 | | 214.29 | | +| 9 | | hands-seat | | | 25 | | | 57.14 | | 214.29 | | + +### I.4 Voltage limit calculation + +Voltage limits to be calculated, with respect to identified cases, correspond to the values generating the body impedances in Figure I.1 whose current flowing through the contact path has to be less than the limits shown in Tables I.3 and I.4. + +Such calculations are summarized in Table I.5 where voltage value ranges are shown to identify the voltage corresponding to current limit value with respect to "b" curve and to "c1" curve. + +Therefore, it is possible to deduce the following conclusions: + +- For environment type 1, there are no critical cases for a.c. voltage because there is no value less than 65 V a.c.; regarding d.c. voltage, the most critical case is the second one because it presents the smallest range of voltage values with respect to the other one having less than 140 V d.c. +- For environment types 2 and 3, the most critical cases are the 6th and the 9th regarding a.c. voltage and d.c. voltage because they present the smallest range of voltage values with respect to the other ones having less than 65 V a.c. and 140 V d.c., respectively. + +Via mathematical analysis of the values reported in Table I.5, it is possible to associate the limit current value to the relative voltage and define the following critical values: + +- Environment type 1 (Case 2): 105 V d.c. +- Environment types 2 and 3 (Cases 6 and 9): 90 V d.c., 60 V a.c. + +**Table I.5 – Corresponding voltage limits for curves "b" and "c1"** + +| Voltage contact [Volt] | | | | 25 | 50 | 75 | 100 | 125 | 150 | 175 | 200 | Limit current a.c. for 'b' curve [mA] | Voltage range corresponding to limit current a.c. [V] | Limit current d.c. for 'b' curve [mA] | Voltage range corresponding to limit current d.c. [V] | Limit current a.c. for 'c 1 ' curve [mA] | Voltage range corresponding to limit current a.c. [V] | Limit current d.c. for 'c 1 ' curve [mA] | Voltage range corresponding to limit current d.c. [V] | | | | | | | | | | | | | | | | | +|-----------------------------------------------------------------------------------|------------------|--------------------|--------------|----------------|-------------|--------------|--------------|--------------|--------------|-------|---------|---------------------------------------|-------------------------------------------------------|---------------------------------------|-------------------------------------------------------|-----------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------|-------------------------------------------------------|-------|-------|--|--|--|--|--|--|--|--|--|--|--|--|--|--| +| Impedance of human body with respect to surface contact and voltage contact [ohm] | | | | 32 000 | 19 000 | 12 500 | 7 800 | 5 000 | 3 800 | 2 900 | 2 200 | | | | | | | | | | | | | | | | | | | | | | | | | +| Case | Environment type | Condition of shoes | Path contact | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | +| 1 | 1 | wet or damp | hand-feet | k | 75 | | | | | 10 | 75 | 30 | 125-150 | 40 | 150-175 | > 200 | > 200 | 150 | > 200 | > 200 | > 200 | | | | | | | | | | | | | | | +| | | | | Z b | 24 000 | 14 250 | 9 375 | 5 850 | 3 750 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z c | 1200 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z | 25 200 | 15 450 | 10 575 | 7 050 | 4 950 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | I | 0.99 | 3.24 | 7.09 | 14.18 | 25.25 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| 2 | | | hands-feet | k | 50 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z b | 16 000 | 9 500 | 6 250 | 3 900 | 2 500 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z c | 1200 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z | 17 200 | 10 700 | 7 450 | 5 100 | 3 700 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | I | 1.45 | 4.67 | 10.07 | 19.61 | 33.78 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| 3 | | | hand-foot | k | 100 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z b | 32 000 | 19 000 | 12 500 | 7 800 | 5 000 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z c | 1200 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z | 33 200 | 20 200 | 13 700 | 9 000 | 6 200 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | I | 0.75 | 2.48 | 5.47 | 11.11 | 20.16 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| 4 | | | hand-hand | k | 100 | | | | | 25 | 125-150 | 75 | 175-200 | 100 | > 200 | 375 | > 200 | > 200 | > 200 | > 200 | > 200 | | | | | | | | | | | | | | | +| | | | | Z b | 32 000 | 19 000 | 12 500 | 7 800 | 5 000 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z c | 200 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z | 32 200 | 19 200 | 12 700 | 8 000 | 5 200 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | I | 0.78 | 2.60 | 5.91 | 12.50 | 24.04 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| 5 | | | hand-seat | k | 50 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z b | 16 000 | 9 500 | 6 250 | 3 900 | 2 500 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z c | 200 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z | 16 200 | 9 700 | 6 450 | 4 100 | 2 700 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | I | 1.54 | 5.15 | 11.63 | 24.39 | 46.30 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| 6 | | | hands-seat | k | 25 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z b | 8 000 | 4 750 | 3 125 | 1 950 | 1 250 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z c | 200 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z | 8 200 | 4 950 | 3 325 | 2 150 | 1 450 | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | I | 3.05 | 10.10 | 22.56 | 46.51 | 86.21 | | | | | | | | | | | | | | | | | | | | | | | | | | | + +**Table I.5 – Corresponding voltage limits for curves "b" and "c1"** + +| Voltage contact [Volt] | | | | 25 | 50 | 75 | 100 | 125 | 150 | 175 | 200 | Limit current a.c. for 'b' curve [mA] | Voltage range corresponding to limit current a.c. [V] | Limit current d.c. for 'b' curve [mA] | Voltage range corresponding to limit current d.c. [V] | Limit current a.c. for 'c 1 ' curve [mA] | Voltage range corresponding to limit current a.c. [V] | Limit current d.c. for 'c 1 ' curve [mA] | Voltage range corresponding to limit current d.c. [V] | | | | | | | | | | | | | | +|-----------------------------------------------------------------------------------|------------------|--------------------|--------------|----------------|-------------|--------------|--------------|--------------|---------------|---------------|---------------|---------------------------------------|-------------------------------------------------------|---------------------------------------|-------------------------------------------------------|-----------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------|-------------------------------------------------------|--|--|--|--|--|--|--|--|--|--|--|--|--| +| Impedance of human body with respect to surface contact and voltage contact [ohm] | | | | 32 000 | 19 000 | 12 500 | 7 800 | 5 000 | 3 800 | 2 900 | 2 200 | | | | | | | | | | | | | | | | | | | | | | +| Case | Environment type | Condition of shoes | Path contact | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | +| 7 | 3 | | hand-hand | k | 100 | | | | | | | 25 | 125 | 75 | 175-200 | 100 | > 200 | 375 | > 200 | | | | | | | | | | | | | | +| | | | | Z b | 32 000 | 19 000 | 12 500 | 7 800 | 5 000 | 3 800 | 2 900 | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z c | 0 | | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z | 32 000 | 19 000 | 12 500 | 7 800 | 5 000 | 3 800 | 2 900 | | | | | | | | | | | | | | | | | | | | | | +| | | | | I | 0.78 | 2.63 | 6.00 | 12.82 | 25.00 | 39.47 | 60.34 | | | | | | | | | | | | | | | | | | | | | | +| 8 | | | hand-seat | k | 50 | | | | | | | 14.29 | 75-100 | 42.86 | 100-125 | 57.14 | 125-150 | 214.29 | > 200 | | | | | | | | | | | | | | +| | | | | Z b | 16 000 | 9 500 | 6 250 | 3 900 | 2 500 | 1 900 | 1 450 | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z c | 0 | | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z | 16 000 | 9 500 | 6 250 | 3 900 | 2 500 | 1 900 | 1 450 | | | | | | | | | | | | | | | | | | | | | | +| | | | | I | 1.56 | 5.26 | 12.00 | 25.64 | 50.00 | 78.95 | 120.69 | | | | | | | | | | | | | | | | | | | | | | +| 9 | | | hands-seat | k | 25 | | | | | | | | 50-75 | | 75-100 | | 100-125 | | 150-175 | | | | | | | | | | | | | | +| | | | | Z b | 8 000 | 4 750 | 3 125 | 1 950 | 1 250 | 950 | 725 | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z c | 0 | | | | | | | | | | | | | | | | | | | | | | | | | | | | +| | | | | Z | 8 000 | 4 750 | 3 125 | 1 950 | 1 250 | 950 | 725 | | | | | | | | | | | | | | | | | | | | | | +| | | | | I | 3.13 | 10.53 | 24.00 | 51.28 | 100.00 | 157.89 | 241.38 | | | | | | | | | | | | | | | | | | | | | | + +# Appendix II + +## Cross reference table of IEC 60950 and IEC 62368 terms + +(This appendix does not form an integral part of this Recommendation.) + +Comparison of terms and definitions from the IEC 60950 series that are quoted in this Recommendation and those of the IEC 62368 series. Terms not in the [IEC 62368-1] definitions, but described in the body text, are noted as SUMMARISED. + +**Table II.1 – Comparison of IEC 60950 series and IEC 62368 series terms** + +| 60950-1/-21 terms | Similar 62368-1/-3 term | | | | | | | | | | | | | | | | | +|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------|----------------------------|-------------------------------------------------------------|--|--------------------------------------------------------|--------------------------------------------------------|----------------------------|-------------------------------------------------------------|-----|-----|---------------|---------------|----|----------------|--------------|---------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +|

SELV, Safety Extra Low Voltage, circuit
secondary circuit that is so designed and protected that under normal operating conditions and single fault conditions, its voltages do not exceed a safe value

Note 1 – The limit values of voltages under normal operating conditions and single fault conditions (see clause 1.4.14) are specified in clause 2.2. See also Table 1A.
Note 2 – This definition of an SELV circuit differs from the term "SELV system" as used in IEC 61140.

Table 1A – Voltage ranges of SELV and TNV circuits

Overvoltages Normal operating voltages
Overvoltages from TELECOMMUNICATION NETWORKS possible? Overvoltages from CABLE DISTRIBUTION SYSTEMS possible? Within SELV CIRCUIT limits Exceeding SELV CIRCUIT limits but within TNV CIRCUIT limits
Yes Yes TNV-1 CIRCUIT TNV-3 CIRCUIT
No Not applicable SELV CIRCUIT TNV-2 CIRCUIT
| Overvoltages | | Normal operating voltages | | Overvoltages from TELECOMMUNICATION NETWORKS possible? | Overvoltages from CABLE DISTRIBUTION SYSTEMS possible? | Within SELV CIRCUIT limits | Exceeding SELV CIRCUIT limits but within TNV CIRCUIT limits | Yes | Yes | TNV-1 CIRCUIT | TNV-3 CIRCUIT | No | Not applicable | SELV CIRCUIT | TNV-2 CIRCUIT |

ES1, electrical Energy Source class 1
class 1 electrical energy source with levels not exceeding ES1 limits under normal operating conditions and abnormal operating conditions that do not lead to a single fault conditions and not exceeding ES2 limits under single fault conditions of a basic safeguard

Note 1 – ES1 may be accessible to an ordinary person (user in [IEC 60950-1] terms). ES1 effects are not painful on the body but may be detectable and ignition of combustible materials not likely.
Note 2 – SUMMARISED

| +| Overvoltages | | Normal operating voltages | | | | | | | | | | | | | | | | +| Overvoltages from TELECOMMUNICATION NETWORKS possible? | Overvoltages from CABLE DISTRIBUTION SYSTEMS possible? | Within SELV CIRCUIT limits | Exceeding SELV CIRCUIT limits but within TNV CIRCUIT limits | | | | | | | | | | | | | | | +| Yes | Yes | TNV-1 CIRCUIT | TNV-3 CIRCUIT | | | | | | | | | | | | | | | +| No | Not applicable | SELV CIRCUIT | TNV-2 CIRCUIT | | | | | | | | | | | | | | | + +**Table II.1 – Comparison of IEC 60950 series and IEC 62368 series terms** + +| 60950-1/-21 terms | Similar 62368-1/-3 term | | | | | | | | | | | | | | | | | +|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------|-------------------------------------------------------------|--|--------------------------------------------------------|--------------------------------------------------------|----------------------------|-------------------------------------------------------------|-----|-----|---------------|---------------|----|----------------|--------------|---------------|------------------------------------------| +|

TNV, Telecommunication Network Voltage, circuit
circuit that is in the equipment and to which the accessible area of contact is limited and that is so designed and protected that, under normal operating conditions and single fault conditions (see clause 1.4.14), the voltages do not exceed specified limit values

A TNV circuit is considered to be a secondary circuit in the meaning of this standard.

Note 1 – The specified limit values of voltages under normal operating conditions and single fault conditions (see clause 1.4.14) are given in clause 2.3.1. Requirements regarding accessibility of TNV circuits are given in clause 2.1.1.1.

Note 2 – Conductive parts of an interconnecting cable may be part of a circuit as stated in clause 1.2.11.6.

TNV circuits are classified as TNV-1 circuits, TNV-2 circuits and TNV-3 circuits as defined in clauses 1.2.8.12, 1.2.8.13 and 1.2.8.14.

Note 3 – The voltage relationships between SELV and TNV circuits are shown in Table 1A.

Table 1A – Voltage ranges of SELV and TNV circuits

Overvoltages Normal operating voltages
Overvoltages from TELECOMMUNICATION NETWORKS possible? Overvoltages from CABLE DISTRIBUTION SYSTEMS possible? Within SELV CIRCUIT limits Exceeding SELV CIRCUIT limits but within TNV CIRCUIT limits
Yes Yes TNV-1 CIRCUIT TNV-3 CIRCUIT
No Not applicable SELV CIRCUIT TNV-2 CIRCUIT
| Overvoltages | | Normal operating voltages | | Overvoltages from TELECOMMUNICATION NETWORKS possible? | Overvoltages from CABLE DISTRIBUTION SYSTEMS possible? | Within SELV CIRCUIT limits | Exceeding SELV CIRCUIT limits but within TNV CIRCUIT limits | Yes | Yes | TNV-1 CIRCUIT | TNV-3 CIRCUIT | No | Not applicable | SELV CIRCUIT | TNV-2 CIRCUIT | See detailed TNV classes for comparison. | +| Overvoltages | | Normal operating voltages | | | | | | | | | | | | | | | | +| Overvoltages from TELECOMMUNICATION NETWORKS possible? | Overvoltages from CABLE DISTRIBUTION SYSTEMS possible? | Within SELV CIRCUIT limits | Exceeding SELV CIRCUIT limits but within TNV CIRCUIT limits | | | | | | | | | | | | | | | +| Yes | Yes | TNV-1 CIRCUIT | TNV-3 CIRCUIT | | | | | | | | | | | | | | | +| No | Not applicable | SELV CIRCUIT | TNV-2 CIRCUIT | | | | | | | | | | | | | | | +|

TNV-1, Telecommunication Network Voltage class 1, circuit

TNV circuit

  • – whose normal operating voltages do not exceed the limits for an SELV circuit under normal operating conditions and
  • – on which overvoltages from telecommunication networks and cable distribution systems are possible
|

ES1 DC voltage on which overvoltages from telecommunication networks and cable distribution systems are possible.

Note – The electrical characteristics are not identical to TNV circuits but will give equivalent level of voltage safety.

ES1, electrical Energy Source class 1

class 1 electrical energy source with levels not exceeding ES1 limits under normal operating conditions and abnormal operating conditions that do not lead to a single fault conditions and not exceeding ES2 limits under single fault conditions of a basic safeguard

Note 1 – ES1 may be accessible to an ordinary person (user in [IEC 60950-1] terms). ES1 effects are not painful on the body but may be detectable and ignition of combustible materials not likely.

Note 2 – SUMMARISED

| | | | | | | | | | | | | | | | | + +**Table II.1 – Comparison of IEC 60950 series and IEC 62368 series terms** + +| 60950-1/-21 terms | Similar 62368-1/-3 term | +|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +|

TNV-2, Telecommunication Network Voltage class 2, circuit

TNV circuit

  • – whose normal operating voltages exceed the limits for an SELV circuit under normal operating conditions and
  • – which is not subject to overvoltages from telecommunication networks
|

ES2 DC voltage not subject to overvoltages from telecommunication networks.

ES2, electrical energy source class 2

class 2 electrical energy source with levels not exceeding ES2 limits under normal operating conditions, abnormal operating conditions, and single fault conditions, but is not ES1.

Note 1 – ES2 may be accessible to an instructed person (no [IEC 60950-1] equivalent to someone under supervision). ES2 effects are; painful on the body, but not an injury Ignition of combustible materials possible, but limited growth and spread of fire

Note 2 – ES2 circuits are not identical to TNV circuits but will give equivalent level of voltage safety.

Note 3 – SUMMARISED

| +|

TNV-3, Telecommunication Network Voltage class 3, circuit

TNV circuit

  • – whose normal operating voltages exceed the limits for an SELV circuit under normal operating conditions and
  • – on which overvoltages from telecommunication networks and cable distribution systems are possible
|

ES2 DC voltage subject to overvoltages from telecommunication networks.

ES2, electrical energy source class 2

class 2 electrical energy source with levels not exceeding ES2 limits under normal operating conditions, abnormal operating conditions, and single fault conditions, but is not ES1.

Note 1 – ES2 may be accessible to an instructed person (no [IEC 60950-1] equivalent to someone under supervision). ES2 effects are; painful on the body, but not an injury Ignition of combustible materials possible, but limited growth and spread of fire

Note 2 – ES2 circuits are not identical to TNV circuits but will give equivalent level of voltage safety.

Note 3 – SUMMARISED

| +|

user

any person, other than a service person.

The term user in this standard is the same as the term operator and the two terms can be interchanged

|

ordinary person

person who is neither a skilled person nor an instructed person

| +|

operator

see user

|

See ordinary person

| + +**Table II.1 – Comparison of IEC 60950 series and IEC 62368 series terms** + +| 60950-1/-21 terms | Similar 62368-1/-3 term | +|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +|

telecommunication network

metallically terminated transmission medium intended for communication between equipment that may be located in separate buildings, excluding:

  • – the mains system for supply, transmission and distribution of electrical power, if used as a telecommunication transmission medium;
  • – cable distribution systems;
  • – SELV circuits connecting units of information technology equipment

Note 1 – The term telecommunication network is defined in terms of its functionality, not its electrical characteristics. A telecommunication network is not itself defined as being either an SELV circuit or a TNV circuit. Only the circuits in the equipment are so classified.

Note 2 – A telecommunication network may be:

  • – publicly or privately owned;
  • – subject to transient overvoltages due to atmospheric discharges and faults in power distribution systems;
  • – subject to longitudinal (common mode) voltages induced from nearby power lines or electric traction lines.

Note 3 – Examples of telecommunication networks are:

  • – a public switched telephone network;
  • – a public data network;
  • – an Integrated Services Digital Network (ISDN);
  • – a private network with electrical interface characteristics similar to the above.
|

information and communication technology network, ICT network

metallically terminated transmission medium and its associated equipment and communication cables

Note 1 – to entry: The cable consists of two or more conductors intended for communication and/or power transfer between the various pieces of equipment. The equipment may be located within the same or separate structures, buildings or locations, excluding:

  • – the mains system for supply, transmission and distribution of electrical power, if used as a communication transmission medium;
  • – a dedicated HBES/BACS network.

Note 2 – to entry: This may include twisted pairs, and may include circuits, that are subjected to transients as indicated by ID1 in Table 14 of [IEC 62368-1]:2014 (assumed to be 1,5 kV).

Note 3 – to entry: An ICT network may be:

  • – publicly or privately owned;
  • – subject to longitudinal (common mode) voltages induced from nearby power lines or electric traction lines.

Note 4 to entry: Examples of ICT networks are:

  • – a public switched telephone network;
  • – a public data network;
  • – an Integrated Services Digital Network (ISDN);
  • – a private network with electrical interface characteristics similar to the above.

Note 5 – to entry: For information about circuit voltages and signals which may be present, see Annex B of IEC 62949:2017.

| +|

None

|

instructed person

person instructed or supervised by a skilled person as to energy sources and who can responsibly use equipment safeguards and precautionary safeguards with respect to those energy sources

Note 1 – to entry: Supervised, as used in the definition, means having the direction and oversight of the performance of others.

Note 2 – to entry: In Germany, in many cases, a person may only be regarded as an instructed person if certain legal requirements are fulfilled.

| +|

service person

person having appropriate technical training and experience necessary to be aware of hazards to which that person may be exposed in performing a task and of measures to minimize the risks to that person or other persons

|

skilled person

person with relevant education or experience to enable him or her to identify hazards and to take appropriate actions to reduce the risks of injury to themselves and others

Note 1 – to entry: In Germany, in many cases, a person may only be regarded as a skilled person if certain legal requirements are fulfilled.

| + +**Table II.1 – Comparison of IEC 60950 series and IEC 62368 series terms** + +| 60950-1/-21 terms | Similar 62368-1/-3 term | +|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +|

cable distribution system

metallically terminated transmission medium using coaxial cable, mainly intended for transmission of video and/or audio signals between separate buildings or between outdoor antennas and buildings, excluding:

  • – the mains system for supply, transmission and distribution of electric power, if used as a communication transmission medium;
  • – telecommunication networks;
  • – SELV circuits connecting units of information technology equipment

Note 1 – Examples of cable distribution systems are:

  • – local area cable networks, community antenna television systems and master antenna television systems providing video and audio signal distribution;
  • – outdoor antennas including satellite dishes, receiving antennas, and other similar devices.

Note 2 – cable distribution systems may be subjected to greater transients than telecommunication networks (see clause 7.4.1).

|

None

| +|

secondary circuit

circuit that has no direct connection to a primary circuit and derives its power from a transformer, converter or equivalent isolation device, or from a battery

Note – Conductive parts of an interconnecting cable may be part of a secondary circuit as stated in clause 1.2.11.6.

|

external circuit

electrical circuit that is external to the equipment and is not mains

Note 1 – to entry: An external circuit is classified as ES1, ES2 or ES3, and PS1, PS2, or PS3.

| + +# Bibliography + +- [b-ITU-T K.51] Recommendation ITU-T K.51 (2016), *Safety criteria for telecommunication equipment.* +- [b-ITU-T Directives-1] ITU-T Directives Vol. VI (2008), *Danger, damage and disturbance.* +- [b-ITU-T Directives-2] ITU-T Directives Vol. VII (1990), *Protective measures and safety precautions.* +- [b-CENELEC HD 637] CENELEC Standard HD 637 51 (1999), *Power installations exceeding 1 kV a.c.* + + + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.65-201101-I_PDF-E/raw.md b/marked/K/T-REC-K.65-201101-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..4dab459bf41ccabe75ed4337b1b0312439ea19c6 --- /dev/null +++ b/marked/K/T-REC-K.65-201101-I_PDF-E/raw.md @@ -0,0 +1,1030 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.65** + +(01/2011) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Overvoltage and overcurrent requirements for +termination modules with contacts for test ports +or surge protective devices** + +Recommendation ITU-T K.65 + + + +# Recommendation ITU-T K.65 + +# Overvoltage and overcurrent requirements for termination modules with contacts for test ports or surge protective devices + +## Summary + +Recommendation ITU-T K.65 specifies the overvoltage requirements and test procedures for termination modules, with contacts for test ports or surge protective devices (SPDs), used for symmetric pair conductors subjected to overvoltages and overcurrents. + +Overvoltages or overcurrents covered by this Recommendation include surges due to lightning on or near the line plant, short-term induction of alternating voltages from adjacent power lines or railway systems, earth potential rise due to power faults, and direct contacts between telecommunication lines and power lines. + +Major changes compared with the 2004 version of this Recommendation include: + +- the addition of a mains contact test to the equipment side of a module with series elements; +- a reduction of the current magnitude for test Figure C.2 and for the customer side test for test Figure C.3 (tests 2.2 and 2.3); +- a revision of Figure E.1 – 10/350 $\mu$ s current generator to be in line with Recommendation ITU-T K.44, Figure II.4-1 – 10/350 $\mu$ s current surge generator; +- the addition of information on the use of fail-safes; +- the addition of a coordination test, for modules with series elements, to check that surges under the firing voltage of the gas discharge tube (GDT) will not damage the series elements; +- the addition of a high voltage a.c. test to simulate a voltage > 230 V a.c. which will operate a 600 V GDT. + +## History + +| Edition | Recommendation | Approval | Study Group | +|---------|----------------|------------|-------------| +| 1.0 | ITU-T K.65 | 2004-12-14 | 5 | +| 2.0 | ITU-T K.65 | 2011-01-13 | 5 | + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2011 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|-----|----------------------------------------------------------------------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 2 | References..... | 2 | +| 3 | Definitions ..... | 2 | +| 3.1 | Terms defined elsewhere ..... | 2 | +| 3.2 | Definitions ..... | 2 | +| 4 | Abbreviations..... | 8 | +| 5 | Conventions ..... | 8 | +| 6 | Service and test conditions ..... | 8 | +| 6.1 | Service conditions ..... | 8 | +| 6.2 | Test temperature and humidity ..... | 9 | +| 6.3 | Termination module and SPD testing..... | 9 | +| 6.4 | Termination module preparation ..... | 9 | +| 6.5 | Test methods..... | 10 | +| 6.6 | Termination module/SPD performance: pass/failure criteria..... | 10 | +| 6.7 | Determining the required tests..... | 11 | +| 6.8 | Acceptance test requirements for termination modules/SPDs in MDFs
which meet certain conditions ..... | 11 | +| 7 | General requirements..... | 12 | +| 7.1 | Manufacturer declaration..... | 12 | +| 7.2 | Use of fail-safes ..... | 12 | +| 7.3 | Breakdown voltage of the termination ..... | 12 | +| 7.4 | Caution ..... | 12 | +| 7.5 | Ball bearings..... | 13 | +| | Annex A – Dimensioning of terminating wires for all voltage/current tests ..... | 19 | +| | Annex B – Connection details for voltage tests on termination modules ..... | 20 | +| | Annex C – Connection details for current tests on termination modules ..... | 25 | +| | Annex D – Test method for tests in aqueous solution ..... | 29 | +| | Annex E ..... | 30 | +| | Appendix I – Information on how to test termination modules with SPDs..... | 31 | +| I.1 | Introduction ..... | 31 | +| I.2 | Termination modules used in the access network ..... | 31 | +| I.3 | Termination modules used in MDFs in operator buildings and customer
premises..... | 32 | + +| | Page | +|-------------------------------------------------------|-------------| +| Appendix II – Application ..... | 34 | +| II.1    Environment ..... | 34 | +| II.2    Termination module and SPD types..... | 34 | +| II.3    Dry termination module and SPD tests ..... | 34 | +| II.4    Filled termination module and SPD tests ..... | 34 | +| II.5    Application ..... | 34 | +| Bibliography..... | 35 | + +# Recommendation ITU-T K.65 + +## Overvoltage and overcurrent requirements for termination modules with contacts for test ports or surge protective devices + +# 1 Scope + +This Recommendation specifies the requirements and test procedures for termination modules with contacts for test ports or SPDs (see clause 3.2.15) used for symmetric pair conductors subjected to overvoltages and overcurrents. + +Note, other Recommendations exist, such as [ITU-T K.12] and [ITU-T K.28], specifying characteristics for surge protective components (SPCs). + +An example of where termination modules included in the scope of this Recommendation may be used is given in Figure 1. The following types of terminating modules covered by this Recommendation are: + +- a termination module with terminals but without the facility for an SPD; +- a termination module with terminals and the facility for an SPD; +- an integral termination module/SPD. The termination module and SPD are not meant to be separated. + +This Recommendation does not cover the requirements of termination modules used in equipment. These are covered by the relevant equipment Recommendations, i.e., [b-ITU-T K.20], [b-ITU-T K.21] or [b-ITU-T K.45]. It does not cover either the requirements of insulation displacement connectors or termination modules without contacts. These are covered by [ITU-T K.55]. + +Refer to Appendix I for information on when and how to test termination modules. + +Basic Recommendation [ITU-T K.44] (test methods and test circuits) is an integral part of this Recommendation. This Recommendation should be read in conjunction with [ITU-T K.11], [ITU-T K.39], [ITU-T K.46], [ITU-T K.47] and [IEC 61643-21]. + +![Figure 1: Example of where termination modules are used in the network. The diagram shows a sequence of components connected in series: Linecard, MDF, Above ground cross-connect frame, Outdoor cabinet/housing, Underground joint, LT and/or NT, and Customer equipment. The components are represented by rectangles, except for the Underground joint which is a circle. The connections are shown by lines, with some lines having small steps or bends.](e2c1c672349c10dccb2563eff6d8260e_img.jpg) + +The diagram illustrates a network configuration with the following components connected in series from left to right: a 'Linecard' (rectangle), an 'MDF' (rectangle), an 'Above ground cross-connect frame' (represented by a vertical line with a semi-circular top), an 'Outdoor cabinet/housing' (rectangle), an 'Underground joint' (circle), an 'LT and/or NT' (rectangle), and 'Customer equipment' (rectangle). The connections between these components are shown by horizontal lines, with some lines having small vertical steps or bends to indicate different levels or types of connections. + +Figure 1: Example of where termination modules are used in the network. The diagram shows a sequence of components connected in series: Linecard, MDF, Above ground cross-connect frame, Outdoor cabinet/housing, Underground joint, LT and/or NT, and Customer equipment. The components are represented by rectangles, except for the Underground joint which is a circle. The connections are shown by lines, with some lines having small steps or bends. + +Termination modules in equipment are covered by the relevant equipment Recommendations + +**Figure 1 – Example of where termination modules are used in the network** + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.11] Recommendation ITU-T K.11 (2009), *Principles of protection against overvoltages and overcurrents*. +- [ITU-T K.12] Recommendation ITU-T K.12 (2010), *Characteristics of gas discharge tubes for the protection of telecommunications installations*. +- [ITU-T K.28] Recommendation ITU-T K.28 (1993), *Characteristics of semi-conductor arrester assemblies for the protection of telecommunications installations*. +- [ITU-T K.39] Recommendation ITU-T K.39 (1996), *Risk assessment of damages to telecommunication sites due to lightning discharges*. +- [ITU-T K.44] Recommendation ITU-T K.44 (2008), *Resistibility tests for telecommunication equipment exposed to overvoltages and overcurrents – Basic Recommendation*. +- [ITU-T K.46] Recommendation ITU-T K.46 (2008), *Protection of telecommunication lines using metallic symmetric conductors against lightning-induced surges*. +- [ITU-T K.47] Recommendation ITU-T K.47 (2008), *Protection of telecommunication lines using metallic conductors against direct lightning discharges*. +- [ITU-T K.55] Recommendation ITU-T K.55 (2002), *Overvoltage and overcurrent requirements for insulation displacement connectors (IDC) terminations*. +- [ITU-T K.77] Recommendation ITU-T K.77 (2009), *Characteristics of metal oxide varistors for the protection of telecommunications installations* +- [ITU-T K.82] Recommendation ITU-T K.82 (2010), *Characteristics and ratings of solid-state, self-restoring overcurrent protectors for the protection of telecommunications installations*. +- [IEC 61643-21] IEC 61643-21 ed1.0 (2009), *Low voltage surge protective devices – Part 21: Surge protective devices connected to telecommunications and signalling networks – Performance requirements and testing methods*. +- [IEC 60695-2-10] IEC 60695-2-10 ed1.0 (2000), *Fire hazard testing – Part 2-10 Glowing/hot-wire based test methods – Glow-wire apparatus and common test procedure*. + +# 3 Definitions + +### 3.1 Terms defined elsewhere + +The majority of definitions used in this Recommendation are defined in [ITU-T K.44]. + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 above ground:** A termination module/surge protective device is considered to be above ground if the joint enclosure is not normally exposed to water. + +**3.2.2 below ground:** A termination module/surge protective device is considered to be used below ground when the joint enclosure may be exposed to damp or wet conditions on a regular basis, e.g., a direct buried joint or a joint in a pit or manhole. A joint installed in a building basement or an enclosure is not considered below ground if flooding and water ingress is prevented. + +**3.2.3 controlled environment:** The humidity is controlled using energy, e.g., air-conditioning. + +**3.2.4 earthing bar:** A part or parts intended for providing an earthing connection from the earth pin of the SPD to earth. This bar may be an integral part of the termination module or a separate component when SPDs are installed. + +**3.2.5 fail-safe:** A device used in conjunction with a surge protective device (SPC) to prevent excessive temperature rise of the SPC. If the SPC reaches a set temperature, due to the current being conducted, the fail-safe will operate and short out the SPC. + +**3.2.6 insulation displacement connector (IDC):** An IDC is an interconnecting or terminating element for symmetric pair conductors where the insulation is mechanically displaced during the termination process. + +A 2-wire connector is used to connect two wires together. + +A 3-wire connector is used to connect a conductor or tap from the main conductor. + +A modular connector, or multi-pair connector, is a connector containing more than one termination. + +Connectors can be either "dry" or "filled". A filled connector is filled with grease or gel to make it moisture resistant. + +**3.2.7 insulation resistance (IR):** Insulation resistance is the resistance from one connection point to an adjacent connection point or earth. + +**3.2.8 protection circuit (PCT):** A protection circuit contains one or more surge protective devices or protective components. It may include a printed circuit board. + +**3.2.9 protection holder:** A component used to support and electrically connect to a protection circuit (PCT). The protection holder and PCT may be integral (not separable). The combination of protection holder and PCT is a surge protective device (SPD). Different holders may be required for matching to the different types of termination modules. The termination module and SPD may also be integral (not separable). + +**3.2.10 protective component (PC):** A protective component is any component used in a protection circuit which cannot be classified as a surge protective device (SPC). Examples of PCs are resistors, PTCs and fail-safes. + +**3.2.11 semi-controlled environment:** An attempt has been made to control the environment by passive means, e.g., by sealing to reduce the probability of water ingress, or by ventilation to reduce the probability of water condensation. + +**3.2.12 surge:** Temporary excessive voltage or current, or both, coupled on a telecommunication line, from an external electrical source. + +NOTE 1 – Typical electrical sources are lightning and AC/DC power systems. + +NOTE 2 – Electrical source coupling can be one or more of the following: electric field (capacitive), magnetic field (inductive), conductive (resistive), electromagnetic field. + +**3.2.13 surge protective component (SPC) (adapted from [b-IEC Electropedia], 151-11-21):** Constitutes part of a surge protective device which cannot be physically divided into smaller parts without losing its protective function. + +NOTE – The protective function is non-linear. Amplitude restriction effectively begins when the amplitude attempts to exceed the predetermined threshold value of the component. + +**3.2.14 surge protective device (SPD):** Device that restricts the voltage of a designated port or ports, caused by a surge, when it exceeds a predetermined level. + +- 1) Secondary functions may be incorporated, such as a current limiting device to restrict a terminal current. +- 2) Typically, the protective circuit has at least one non-linear voltage-limiting surge protective component. +- 3) An SPD is a combination of a protection circuit and holder. + +**3.2.15 termination module:** A termination module is a component used for terminating cable conductors and it contains one or more of the following components: + +- an insulation displacement terminal or conductor terminal; +- contacts; +- test port; and/or +- contacts for at least one SPD. Requirements for SPDs are given in [IEC 61643-21]. + +Termination modules can be either "dry" or "filled". A filled termination module is filled with a grease or a gel to make it moisture resistant. There are three types of termination modules in use (see Figure 3-1). + +**3.2.15.1 termination module; connection-type:** Line side and cross-connect side are permanently connected. Only overvoltage limiting SPDs may be used. + +**3.2.15.2 termination module; disconnection-type:** Line side and cross-connect side are connected via a disconnectable contact. This allows the use of a test plug to open circuit the line and to allow testing in either direction. SPDs to limit overvoltages and to limit surge currents may be used. + +**3.2.15.3 termination module; switching-type:** Line side and cross-connect side are only connected when a shorting plug is inserted. As for the disconnected type, a test plug and an SPD may be used. + +**3.2.16 test port:** A test port is a port that allows a probe to make contact with the terminated conductor, either via an exposed terminal or a gel socket, without having to remove the conductor or damage the conductor insulation. + +**3.2.17 unit under test:** Unit under test (UUT) is a generic term sometimes used to describe the part being tested. + +![Diagram showing three types of termination modules (Connection type, Disconnection type, and Switching type) connected to an SPD. The SPD is shown as a bracketed assembly containing a Protection circuit and a Protection holder. The Termination module is shown as a grey box containing the connection points. The Connection type shows a solid line connection. The Disconnection type shows a disconnectable contact. The Switching type shows a switching contact.](b0211cee4b20034939d883ac0d70f696_img.jpg) + +The diagram illustrates three vertical assemblies representing different termination module types, each connected to a common SPD assembly on the left. The SPD assembly is indicated by a large curly bracket and contains two sub-components: a 'Protection circuit' (top) and a 'Protection holder' (middle). Each assembly sits on a grey rectangular base labeled 'Termination module'. +1. **Connection type:** The top component connects directly through the holder to a single point on the base. +2. **Disconnection type:** The top component connects through the holder to two separate points on the base, which are crossed by an 'X' shape, indicating a disconnectable contact. +3. **Switching type:** Similar to the disconnection type, it connects to two crossed points on the base, but with an additional switch symbol. +Labels on the right side identify the 'Protection circuit', 'Protection holder', and 'Termination module'. A small code 'K.065\_F3-1' is in the bottom right corner. + +Diagram showing three types of termination modules (Connection type, Disconnection type, and Switching type) connected to an SPD. The SPD is shown as a bracketed assembly containing a Protection circuit and a Protection holder. The Termination module is shown as a grey box containing the connection points. The Connection type shows a solid line connection. The Disconnection type shows a disconnectable contact. The Switching type shows a switching contact. + +**Figure 3-1 – Types of termination modules shown with SPDs** + +![A photograph of a white plastic termination module with two rows of pins.](967c30813761a8952ecc5e16bf42ea45_img.jpg) + +A photograph of a white plastic termination module, likely for telecommunications. It features two parallel rows of insulation-displacement contact (IDC) slots. The module has a rectangular white plastic body with grey mounting clips at the ends. + +A photograph of a white plastic termination module with two rows of pins. + +K.065\_F3-2 + +**Figure 3-2 – Example of a termination module** + +![A cross-sectional diagram of a module showing internal contacts and wiring.](3668a836db39d25d24b56180a9c9a7fb_img.jpg) + +A cross-sectional diagram of a module, showing its internal mechanical and electrical structure. On the left, a cable enters the module. Inside, there are two blue contact points on the right, connected by blue wires that wrap around the exterior. A central purple contact is also visible, showing a spring-like connection. The diagram uses various colors (blue, purple, grey, white) to represent different components and their connections within the module's housing. + +A cross-sectional diagram of a module showing internal contacts and wiring. + +K.065\_F3-3 + +**Figure 3-3 – Example of contacts in a module** + +![A photograph of a grey plastic holder with 12 removable SPCs (Super Protection Contacts) inserted into it. The holder has a row of 12 slots, each containing a red and white SPC. The bottom edge of the holder has a series of 12 vertical slots for mounting.](d5a837fa4f4675e5ee596003cf55985c_img.jpg) + +A photograph of a grey plastic holder with 12 removable SPCs (Super Protection Contacts) inserted into it. The holder has a row of 12 slots, each containing a red and white SPC. The bottom edge of the holder has a series of 12 vertical slots for mounting. + +K.065\_F3-4 + +**Figure 3-4 – Example of a holder with removable SPCs** + +![A photograph of an integral termination module and SPD (Surge Protection Device). The module is a grey plastic component with a row of 12 metal contacts visible on its side. It is shown in a partially open position, revealing internal components including a row of 12 metal contacts and a series of 12 vertical slots for mounting.](10953d657a5f47fdc829a800419dd370_img.jpg) + +A photograph of an integral termination module and SPD (Surge Protection Device). The module is a grey plastic component with a row of 12 metal contacts visible on its side. It is shown in a partially open position, revealing internal components including a row of 12 metal contacts and a series of 12 vertical slots for mounting. + +K.065\_F3-5 + +**Figure 3-5 – Example of an integral termination module and SPD** + +![Figure 3-6: A termination module with a removable holder and removable SPCs. The image shows a grey plastic base with 12 slots. A removable grey holder is inserted into the top of the base. Inside the holder, there are 12 red cylindrical components (SPCs) arranged in a row. A yellow label with a red 'M' is visible on the right side of the holder.](0f2a1e4a7b12fe5b8749882ecd636f5c_img.jpg) + +Figure 3-6: A termination module with a removable holder and removable SPCs. The image shows a grey plastic base with 12 slots. A removable grey holder is inserted into the top of the base. Inside the holder, there are 12 red cylindrical components (SPCs) arranged in a row. A yellow label with a red 'M' is visible on the right side of the holder. + +K.065\_F3-6 + +**Figure 3-6 – Example of a termination module with removable holder and removable SPCs** + +![Figure 3-7: A termination module with a removable SPD (integral holder and PCTs). The image shows a grey plastic base with 12 slots. A removable grey holder is inserted into the top of the base. Inside the holder, there are 12 beige rectangular components (PCTs) arranged in a row. A single beige rectangular component (SPD) is shown separately in front of the module.](0cc86fe8fc37b0edc9581f2af9459a52_img.jpg) + +Figure 3-7: A termination module with a removable SPD (integral holder and PCTs). The image shows a grey plastic base with 12 slots. A removable grey holder is inserted into the top of the base. Inside the holder, there are 12 beige rectangular components (PCTs) arranged in a row. A single beige rectangular component (SPD) is shown separately in front of the module. + +K.065\_F3-7 + +**Figure 3-7 – Example of a termination module with removable SPD (integral holder and PCTs)** + +# 4 Abbreviations + +This Recommendation uses the following abbreviations: + +| | | +|-----|---------------------------------------------| +| IDC | Insulation Displacement Connector | +| IR | Insulation Resistance | +| LT | Line Termination | +| MDF | Main Distribution Frame | +| NT | Network Termination | +| PC | Protective Component | +| PCT | Protection Circuit | +| PTC | Positive Temperature Coefficient thermistor | +| SPC | Surge Protective Component | +| SPD | Surge Protective Device | +| SSA | Solid State Arrester | +| UUT | Unit Under Test | + +# 5 Conventions + +This Recommendation uses the following conventions: + +| | | +|---------------------|--------------------------------------------------------------------------------------------------------------------------| +| c | ground connection of the termination module; earthing bar (only applicable to termination modules with protection units) | +| $xa_1, xb_2 - xb_n$ | line side of the termination module | +| $ya_1, yb_2 - yb_n$ | cross-connect side of the termination module | + +# 6 Service and test conditions + +General service and test conditions are outlined below. + +### 6.1 Service conditions + +#### 6.1.1 Normal service conditions + +##### Air pressure + +Air pressure 80 kPa to 160 kPa. This air pressure represents an altitude of $-500$ m to $+2\,000$ m. + +##### Temperature and humidity service conditions + +For an uncontrolled environment, the temperature range is between the values of $-40^\circ\text{C}$ and $+70^\circ\text{C}$ . The humidity range is between the values of 5% and 96% RH. + +For a controlled environment, the temperature range is between the values of $-5^\circ\text{C}$ and $+40^\circ\text{C}$ . The humidity range is between the values of 10% and 80% RH. + +#### 6.1.2 Abnormal service conditions + +Exposure of the termination module and SPD to abnormal service conditions may require special consideration in their design or application and shall be called to the attention of the manufacturer(s). + +### 6.2 Test temperature and humidity + +If it is known beforehand that a particular device technology causes the UUT to be insensitive to temperature when testing a particular characteristic, a temperature of $23^{\circ}\text{C} \pm 2^{\circ}\text{C}$ with relative humidity from 45% to 55% may be used for that test. + +In other cases, UUT testing shall be performed at the extreme temperatures of the temperature range selected for the intended application. The selected temperature range may be narrower than the full range of clause 6.1, depending on the application. + +For particular UUT technologies, it may be known beforehand that only one of the extreme temperatures of the selected temperature range represents the worst-case test condition. In this case, the testing shall be performed only at the extreme temperature representing the worst-case test condition. This extreme temperature may be different for each test listed in Table 2 for the same UUT technology. + +When testing is required to be performed at extreme temperatures, the UUT shall be gradually heated or cooled to the specified extreme temperature, taking sufficient time to avoid thermal shock. Unless otherwise specified, a minimum of 1 h should be used. The UUT shall be held at the specified temperature for a time sufficient to reach thermal equilibrium before testing. + +Unless otherwise specified, a minimum of 15 min should be used. + +### 6.3 Termination module and SPD testing + +The purpose of this Recommendation is to ensure compatibility of the termination module, holder, PCTs and fail-safe, etc. Therefore, testing generally has to be performed with the various components connected as they are installed in the field. Where this not the case, the test condition will be specified. + +The following categories of termination modules and protection units need to be considered: + +Category 1 – a termination module without the facility for an SPD; + +Category 2 – a termination module with the facility for an SPD; + +Category 3 – an integral termination module/SPD. The termination module and SPD are not meant to be separated. + +Table 1 contains the procedure to test each of the three categories. The relevant tests in Table 2 shall be performed in sequence. + +Refer to Appendix I for guidance on when the various tests apply. + +Type test requirements: The UUT shall meet the tests outlined in the following tables. Connection details for the UUT are given in Annexes B and C. + +A special test condition is used to simulate exposure to moist conditions. The detailed test method is given in Annex D. + +Acceptance test requirements: These tests are made by agreement between the manufacturer and user. + +## 6.4 Termination module preparation + +A minimum of four assembled termination modules shall be terminated according to Figure A.1. Only half the conductors are terminated on the cross-connect side for the voltage breakdown test sequence, see Figures B.1, B.2 and B.3. The termination module shall be terminated, as per the manufacturers instructions, with conductors with solid insulation, see Figure A.1. Both the minimum and maximum conductor sizes specified for the termination module shall be used. It may be necessary to use a heavier conductor, as the minimum conductor size, from the allowable conductor range, during the lightning surge current and power contact test, to prevent the conductor from fusing. + +NOTE – Fusing of the conductor, except at the termination, is not a termination module failure. + +### 6.5 Test methods + +The assembled module shall be tested for its high voltage/current performance in accordance with the tests outlined in Tables 1 and 2. Use half of the assembled samples for tests 1.1 to 1.4 and the rest of the samples for the remainder of the tests. + +Voltage tests are performed without the SPD installed. + +Current tests are required through the termination module, line in – line out, with any SPDs removed unless the SPD is required to complete the circuit. For termination modules with SPDs, current tests are also required line – ground. If the SPDs are always fitted with a fail-safe, the test is only performed with SPDs with fail-safes. + +### 6.6 Termination module/SPD performance: pass/failure criteria + +#### 6.6.1 General + +The assembled UUT shall comply with the test requirements outlined in Table 2. + +Further, the UUT shall not exhibit any of the following modes of failure except where otherwise indicated: + +- flashover to the electrode or foil; +- internal breakdown (blackening of grease); +- physical damage of the termination module or protection unit; +- significant increase in the pull-out force of a removable PCT to holder and removable SPD/holder to termination module. + +Fusing of the conductor, except at the termination, is not a termination module failure. + +#### 6.6.2 Mains power contact + +A termination module may be used in three ways: + +- 1) without an SPD; +- 2) with an SPD without a fail-safe; +- 3) with an SPD with fail-safe. + +Different failure criteria have been set for the three methods of application. + +- Termination module without SPDs: + +For test resistor values of 160 Ω or greater, the termination module shall not be damaged, as per the criteria in clause 6.6.1. For test resistor values less than 160 Ω, the termination module may be damaged, but a fire hazard shall not occur and the adjacent circuits shall not be damaged. + +- Termination module with SPDs without fail-safes: + +Heat damage is allowed to occur in the termination module and SPD under test, and adjacent termination modules and SPD, due to heating of the SPD, but a fire hazard shall not occur. The manufacturer may need to consider and to test with more than one type of SPD if different SPDs will give different results. SPDs chosen for the test must operate during the test unless the manufacturer of the unit excludes the use of SPDs that may operate for mains voltages. + +- Termination module with SPDs with fail-safes: + +For test resistor values of 160 Ω or greater, the termination module and SPD shall not be damaged, as per the criteria in clause 6.6.1. For test resistor values less than 160 Ω, the + +termination module and SPD may be damaged, but a fire hazard shall not occur and the adjacent circuits shall not be damaged. The SPD, chosen for the test, must operate during the test unless the manufacturer of the protection unit excludes the use of SPDs that may operate for mains voltages. + +When the test current is applied to modules with series elements using Figure C.2, for all test resistor values, the termination module may be damaged, but a fire hazard shall not occur and the adjacent circuits shall not be damaged. + +#### **6.6.3 HV a.c. contact** + +This test is a safety test only. For all module types the module is allowed to be damaged but a fire hazard shall not occur. + +Samples shall have 10 A rms (from a 1500 volt source) passed from the line electrodes to the earth electrode for 30 seconds. The protector unit shall not catch fire or explode. + +### **6.7 Determining the required tests** + +This Recommendation covers a wide application of termination modules and SPDs from those used in an MDF at telecommunication centres, access network shelters and radio base stations to termination blocks at customer premises. It is expected that termination modules and SPDs will be tested in the following sequence: + +- 1) without SPD; +- 2) with SPD without fail-safe function; +- 3) with SPD with fail-safe function. + +If reduced testing is performed, this must be declared by the manufacturer; see clause 7.1. + +## **6.8 Acceptance test requirements for termination modules/SPDs in MDFs which meet certain conditions** + +For the reasons given in Appendix I, the currents which can be conducted in the equipment side of termination modules with SPDs used in network terminations may be less than the surge current conducted in the external cable. If the following conditions are met: + +- the termination module and SPD manufacturer and the operator agree; +- the current is limited in the equipment side wiring by one or more of the following methods: + - a fusible link in the wiring; + - overcurrent protection is contained in the MDF SPD; + - or the SPDs in all equipment connected to the MDF are coordinated with the MDF SPDs; +- this limitation in performance of the termination module/SPD is clearly stated in the manufacturers specification sheet and installation instructions; see clause 7.1, + +the test currents can be reduced as follows: + +#### **6.8.1 Lightning surge current** + +Reduce the test current to 10% of the full test current or apply a 4 kV 10/700 µs surge (which is approximately a 100 A 5/320 µs waveform). + +#### **6.8.2 Mains power current** + +Perform the test with only the 300, 600 and 1000 Ω resistors. + +# **7 General requirements** + +All plastic materials used should be non-flammable or self-extinguishing. The unit shall comply with the requirements of [IEC 60695-2-10]. + +### **7.1 Manufacturer declaration** + +- If the termination module/SPD has been tested using reduced requirements on the equipment side, see clause 6.8, this should be stated in the manufacturer-provided specification sheet and installation instructions. +- If the protection unit requires the SPD to be fitted with a fail-safe, to comply with clause 6.6.2, this should be stated in the manufacturer-provided specification sheet and installation instructions. +- If the termination module has a lower breakdown voltage than that required by tests 1.2 and 1.3 in Table 1, and needs an SPD to protect it from voltage breakdown, this should be stated in the manufacturer-provided specification sheet and installation instructions. + +## **7.2 Use of fail-safes** + +To prevent damage to the termination module and SPD, it may be necessary to use a fail-safe to prevent the SPD from becoming overheated. This is a decision for the operator. This decision could consider the following: + +- probability of mains power contact; +- health and safety issues (smoke from the plastic termination module or SPD may be toxic); +- importance of the installation. + +Care should be taken with using fail-safes on GDTs which are not allowed to operate in the presence of mains voltages. This could be an operator or a national requirement. If a HV a.c. surge operates the fail-safe, the GDT will no longer block mains voltages. The risk may be low if operation of the fail-safe causes a service outage and if the operator has adequate practices which ensures that staff check for hazardous voltages on the line or use other safeguards to prevent staff contact with the line. A safety hazard may exist where operation of the fail-safe will not cause a service outage, e.g., if the GDT is used to bond a telecommunication earth to a mains earth. + +### **7.3 Breakdown voltage of the termination** + +The breakdown voltage of the termination, see test 1.3 in Table 1, has been set to coordinate with [b-IEC 61663-2]. If the operator wants to prevent breakdown and possible damage to the termination module, in a network using cables with conductors having higher insulation breakdown voltages, the use of SPDs to prevent breakdown of the termination module may need to be considered. + +## **7.4 Caution** + +Before deciding to use a termination module and SPD with reduced requirements on the equipment side, check that the current will be limited; see clause 6.8. + +## 7.5 Ball bearings + +Ball bearings used as an electrode shall have a diameter of $3.1 \text{ mm} \pm 0.1 \text{ mm}$ . + +**Table 1a – Test method for different categories of termination modules +(Tests 1.1-1.4)** + +| Test | Category 1:
a termination module
without the facility
for an SPD | Category 2:
a termination module with
a removable SPD | Category 3:
a termination module with
an SPD not meant to be
removed | +|------|---------------------------------------------------------------------------|------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 1.1 | Test as supplied.
(Notes 2 and 4) | Test module without holder
and SPD/fail-safe.
(Note 5) | Test with holder but without
protection circuit/fail-safe at
a reduced test voltage = 1.2
times the maximum d.c.
operating voltage of the
SPD, see Notes 1 and 3. | +| 1.2 | Test as supplied.
(Notes 2 and 4) | Test module without holder
and SPD/fail-safe, see
clause 7.1. (Note 5) | Test with holder but without
protection circuit/fail-safe at
a reduced test voltage = 1.2
times the maximum d.c.
operating voltage of the
SPD, see Notes 1 and 3. | +| 1.3 | Test as supplied.
(Notes 2 and 4) | Test module without holder
and SPD/fail-safe, see
clause 7.1. (Note 5) | Test with holder but without
protection circuit/fail-safe at
a reduced test voltage = 2
times the maximum d.c.
operating voltage of the
SPD, see Notes 1 and 3. | +| 1.4 | Test as supplied.
(Notes 2 and 4) | Test module without holder
and SPD/fail-safe.
(Note 5) | Test with holder but without
protection circuit/fail-safe at
a reduced test voltage = 1.2
times the maximum d.c.
operating voltage of the
SPD, see Notes 1 and 3. | + +NOTE 1 – The operating voltage of the SPD is the sparkover voltage for an SPD (or equivalent for an SSA) or the voltage at which a clamping device conducts 1 mA. + +NOTE 2 – If an SPD is to be inserted into the test port, test the module and SPD combination as category 2. + +NOTE 3 – It may be necessary to de-solder or cut away the protection circuit. + +NOTE 4 – If a link or plug is required to complete the circuit, insert this item. + +NOTE 5 – If a link or plug is required to complete the circuit, when the SPD is not used, insert this item. + +**Table 1b – Test method for different categories of termination modules +(Tests 2.1-2.7)** + +| Test | Category 1:
a termination module
without the facility
for an SPD | Category 2:
a termination module with
a removable SPD | Category 3:
a termination module with
an SPD not meant to be
removed | +|-------------|-------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------| +| 2.1 | Test as supplied.
(Note 1) | Test module with SPD (with or without fail-safe), see Note 2. If the circuit is completed without the SPD, repeat the test with it removed. | Test as supplied.
(See Note 2) | +| 2.2 | Test as supplied. (Note 1)
Test with Figure C.2 only. | Test module with SPD, see Note 3. If the circuit is completed without the SPD, repeat the test with it removed using Figure C.2 only. | Test as supplied. | +| 2.3 | Test as supplied. (Note 1)
Test with Figure C.2 only. | Test module with SPD, see Note 3. If the circuit is completed without the SPD, repeat the test with it removed using Figure C.2 only. | Test as supplied. | +| 2.4 | N.A. | Test module with holder and SPD, see Note 3. | Test as supplied. | +| 2.5 | Test as supplied. (Note 1) | Test module with SPD (with or without fail-safe), see Note 2. If the circuit is completed without the SPD, repeat the test with it removed. | Test as supplied.
(See Note 2) | +| 2.6 | Test as supplied. (Note 1)
Test with Figure C.2 only. | See clause 6.6. Test module with SPD, see Note 3. See clause 7.1. | Test as supplied. | +| 2.7 | Test as supplied. (Note 1)
Test with Figure C.2 only. | See clause 6.6. Test module with SPD, see Note 3. See clause 7.1 | Test as supplied. | + +NOTE 1 – If a link or plug is required to complete the circuit, insert this item. + +NOTE 2 – If the SPD has a series component, e.g., a resistor or PTC, short circuit this element. + +NOTE 3 – Perform test with and without fail-safe on the SPD unless the SPD and termination module manufacturer specifies that only an SPD with a fail-safe will be used. + +**Table 2 – Requirements and test procedures for terminating modules and SPDs** + +| Test sequence | Test description | Test circuit and waveshape | Test level | No. of tests | Acceptance criteria | Comments | +|---------------|--------------------------------------|----------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------|--------------------|-----------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 1.1 | Insulation resistance (Initial) | IR test instrument; Figure B.1. | $U = 500 \text{ V DC}$
$t = 60 \text{ s}$ | 1 | $\geq 100 \text{ M}\Omega$ | Prepare the UUT as follows:
For dry units: completely wrap the assembled unit in aluminium foil or place in ball bearings (Note 2).
For filled units: place the assembled unit in an aqueous solution, see Figure D.1.
Measure the IR conductor to foil/bearings or electrode at the end of the test period. Measure the IR conductor to conductor at the end of the test period. | +| 1.2 | AC voltage breakdown test | Figure A.3-6 of [ITU-T K.44] with Figures B.2 and B.3. | Frequency = 50 Hz
$U_{ac} = 1000 \text{ V}$ (basic)
$U_{ac} = 3000 \text{ V}$ (enhanced)
$R = 100 \text{ k}\Omega$
$t = 60 \text{ s}$ | 1 | No failure as specified in clause 6.6.1 | Prepare the UUT as described for test 1.1.
Apply the AC voltage between the conductors tied together and the foil/bearings or electrode. Apply the AC voltage between adjacent conductors.
See Note 3. | +| 1.3 | Lightning surge voltage test | Figure A.3-1 of [ITU-T K.44] with Figures B.2 and B.3.
10/700 $\mu\text{s}$ . | $U_c = 5 \text{ kV}$
$R = 25 \Omega$ | 5 of each polarity | No failure as specified in clause 6.6.1 | Prepare the UUT as described for test 1.1.
Apply the impulse voltage between the conductors tied together and the foil or electrode.
Apply the impulse voltage between adjacent conductors. | +| 1.4 | Insulation resistance (Final) | IR test instrument; Figure B.1. | $U = 500 \text{ V DC}$
$t = 60 \text{ s}$ | 1 | $\geq 100 \text{ M}\Omega$ | Repeat test 1.1. | +| 2.1 | Connection resistance test (Initial) | 4-wire resistance measurement instrument. Figure C.1 | | 1 | $\leq 25 \text{ m}\Omega$ | The connection resistance shall be measured for each termination and recorded. Any series element, e.g., a PTC, shall be short circuited for this test. | + +**Table 2 – Requirements and test procedures for terminating modules and SPDs** + +| Test sequence | Test description | Test circuit and waveshape | Test level | No. of tests | Acceptance criteria | Comments | +|---------------|---------------------------------------------------|-----------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------|--------------------|--------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 2.2 | Lightning surge current test | Figure A.3-4 of [ITU-T K.44] with Figures C.2 and C.3.
8/20 µs | I = 1 or 2.5 or 5 or 10 or 20 kA (aligned with [ITU-T K.12]).
Minimum test level for enhanced = 5 kA.
(Note 1) | 5 of each polarity | No failure as specified in clause 6.6.1 | For terminal modules with SPDs, the test value depends on the rating of the SPC chosen from [ITU-T K.12] or [ITU-T K.28].
With the unit insulated, the test current is applied through the termination.
If the SPD contains series elements:
– Figure C.2 does not apply
– Only apply test to line side for Figure C.3 | +| 2.3 | High energy lightning current | Figure E.1 with Figures C.2 and C.3.
10/350 µs | I = 0.5, 1 or 2.5 or 4 kA (aligned with [ITU-T K.12]).
Minimum test level for enhanced = 1 kA.
(Note 1) | 5 of each polarity | No failure as specified in clause 6.6.1 | See test 2.2 | +| 2.4 | Lightning surge current test for the earthing bar | Figures A.3-4 of [ITU-T K.44] and C.4
8/20 µs | I = 6 times the test level in test 2.2 above, maximum 30 kA total.
(Note 1) | 1 | No failure as specified in clause 6.6.1 | With the unit insulated, the test current is applied.
If the SPD contains series elements, Figure C.2 does not apply.
Only apply test to line side for Figure C.3 | +| 2.5 | Connection resistance test (Final) | 4-wire resistance measurement instrument. Figure C.1. | | 1 | delta ≤ 2.5 mΩ; maximum change of the resistance | Repeat test 2.1 | +| 2.6 | Mains power contact. Test AC durability | Figure A.3-6 of [ITU-T K.44] with Figures C.2 and C.3.
Frequency = 50 Hz | U ac. = 230 V
T = 15 min.
R = 10, 20, 40, 80, 160, 300, 600 and 1000 Ω.
(Notes 1, 4 and 5) | 1 | No failure as specified in clause 6.6.2 | With the unit insulated, the test current is applied. | + +**Table 2 – Requirements and test procedures for terminating modules and SPDs** + +| Test sequence | Test description | Test circuit and waveshape | Test level | No. of tests | Acceptance criteria | Comments | +|---------------|------------------------------------|------------------------------------------------------------------------------|-------------------------------------------------------------------------------------|--------------|-----------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------| +| 2.7 | HV a.c contact. Test AC durability | Figure A.3-6 of [ITU-T K.44] with Figures C.2 and C.3.
Frequency = 50 Hz. | $U_{ac} = 1500 \text{ V}$
$T = 30 \text{ s}$ .
$R = 150 \Omega$ .
(Note 1) | 1 | No failure as specified in clause 6.6.3 | With the unit insulated, the test current is applied. If the SPD contains series elements, only apply the test to the line side for Figure C.3 | + +NOTE 1 – It may be necessary to use a heavier gauge conductor for the minimum size conductor, within the allowable conductor range, for tests 2.2-2.4 and 2.6 to prevent the conductor from fusing. + +NOTE 2 – The aluminium foil is used to simulate an adjacent earthed metal surface or bare conductor. If easier, the test may be performed by placing each of the six faces of the protection unit on a ground plane in turn. + +NOTE 3 – To reduce the effects of the total capacitance on leakage current, it may be necessary to test one conductor at a time. + +NOTE 4 – Refer to clause I.1.4 of [ITU-T K.44], Mains power contact, with respect to a reduced number of tests for mains power contact. + +NOTE 5 – The AC mains voltage and frequency for test 2.6 may be changed to the local mains supply voltage and frequency values. For AC test voltage values other than 230 V, the test resistor values should be adjusted to provide the same prospective short-circuit current values that occur in the 230 V test condition. + +**Table 3 – Additional requirements and test procedures for modules with SPDs that contain series elements** + +| Test sequence | Test description | Test circuit and waveshape | Test level | No. of tests | SPD | Acceptance criteria | Comments | +|---------------|----------------------------------------|-----------------------------------------------------------|---------------------------------------------------------|--------------------|-------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 1.1 | Lightning, coordination, transverse | Figure A.3-1 of [ITU-T K.44] with Figure B.4
10/700 µs | $U_{c(max)} = 4 \text{ kV}$
$R = 25 \text{ } \Omega$ | 5 of each polarity | Special test protector; see 8.4 of [ITU-T K.44] | A, see [ITU-T K.44].
When the test is performed with $U_c = U_{c(max)}$ , the special test protector must operate. Of course, it may also operate with a voltage of $U_c < U_{cmax}$ . | The SPD GDT is replaced with a special test protector, see [ITU-T K.44]. $U_c$ is adjusted to just less than that which operates the special test protector. | +| 1.2 | Lightning, coordination, port to earth | Figure A.3-1 of [ITU-T K.44] with Figure B.5
10/700 µs | | | | | | + +## Annex A + +### Dimensioning of terminating wires for all voltage/current tests + +(This annex forms an integral part of this Recommendation) + +![Diagram of a termination module showing dimensions A, B, xa, xb, ya, and yb for n pairs of wires.](26d664119ad25250780f554633444e54_img.jpg) + +The diagram illustrates a central 'Termination module' with multiple pairs of wires extending from it. On the left side, the wires are labeled $xa_1, xb_1, \dots, xa_n, xb_n$ . On the right side, they are labeled $ya_1, yb_1, \dots, ya_n, yb_n$ . Dimension $A(\pm 1 \text{ mm})$ is shown as the distance from the left edge of the module to the start of the wire pairs. Dimension $B$ is shown as the distance from the left edge of the module to the start of the first pair of wires ( $xa_1, ya_1$ ). The label 'K.065\_FA.1' is present in the bottom right corner of the diagram. + +Diagram of a termination module showing dimensions A, B, xa, xb, ya, and yb for n pairs of wires. + +where $n$ = number of pair terminations + +- | | | +|----------------------|-----------------------| +| (i) For voltage test | (ii) For current test | +| $A = 250 \text{ mm}$ | $A = 90 \text{ mm}$ | +| $B = 20 \text{ mm}$ | $B = 30 \text{ mm}$ | + +**Figure A.1 – Dimensions of terminating wires for termination modules** + +## Annex B + +### Connection details for voltage tests on termination modules + +(This annex forms an integral part of this Recommendation) + +![Diagram of a termination module for voltage tests. It shows a central 'Termination module' block with multiple pairs of conductors entering from the left (labeled xa1, xb1, xa2, xb2, ..., xan, xbn) and exiting to the right (labeled ya1, yb1, ..., yan/2, ybn/2). An IR meter is connected between the left-side conductors and an earth rail/electrode (labeled '1'). A note indicates 'Leave half the terminations unterminated' and 'n = the number of pair terminations'. The diagram is labeled K.065_FB.1.](90ddb84c323b956e2d50a54d3f870566_img.jpg) + +Diagram illustrating the connection details for voltage tests on termination modules. A central 'Termination module' block is shown. On the left, conductors are labeled $xa_1, xb_1, xa_2, xb_2, \dots, xa_n, xb_n$ . On the right, conductors are labeled $ya_1, yb_1, \dots, ya_{n/2}, yb_{n/2}$ . An IR meter is connected between the left-side conductors and an earth rail/electrode (labeled '1'). A note indicates 'Leave half the terminations unterminated' and 'n = the number of pair terminations'. The diagram is labeled K.065\_FB.1. + +Diagram of a termination module for voltage tests. It shows a central 'Termination module' block with multiple pairs of conductors entering from the left (labeled xa1, xb1, xa2, xb2, ..., xan, xbn) and exiting to the right (labeled ya1, yb1, ..., yan/2, ybn/2). An IR meter is connected between the left-side conductors and an earth rail/electrode (labeled '1'). A note indicates 'Leave half the terminations unterminated' and 'n = the number of pair terminations'. The diagram is labeled K.065\_FB.1. + +1 Earth rail/electrode in aqueous solution or foil/bearings + +Insulation resistance test sequence: + +**Test, conductor to conductor** + +$xa_1 - xb_1$ + $xb_1 - xa_2$ + $xa_2 - xb_2$ + | + $xa_n - xb_n$ + +**Test, conductor earthing bar in parallel with electrode in aqueous solution, foil or ball bearings** + +$xa_1$ to 1 + $xb_1$ to 1 + $xa_2$ to 1 + | + $xb_n$ to 1 + +**Figure B.1 – Connection detail for insulation resistance test** + +![Diagram showing the connection detail for AC and lightning surge voltage test. A central 'Termination module' is connected to multiple pairs of conductors labeled xa1, xb1, xa2, xb2, ..., xan, xbn on the left. On the right, the conductors are labeled ya1, yb1, ..., yan/2, ybn/2. A note indicates 'Leave half the terminations unterminated'. The conductors are connected to a 'Voltage source' labeled '1', which is further connected to an earthing bar (1).](aaf3e6e44cdeabd6d1df869c5f392ea1_img.jpg) + +xa1 +xb1 +xa2 +xb2 +xan +xbn + +ya1 +yb1 +yan/2 +ybn/2 + +**Termination +module** + +*Leave half the terminations +unterminated* + +n = the number of pair terminations + +Voltage +source + +1 + +K.065\_FB.2 + +Diagram showing the connection detail for AC and lightning surge voltage test. A central 'Termination module' is connected to multiple pairs of conductors labeled xa1, xb1, xa2, xb2, ..., xan, xbn on the left. On the right, the conductors are labeled ya1, yb1, ..., yan/2, ybn/2. A note indicates 'Leave half the terminations unterminated'. The conductors are connected to a 'Voltage source' labeled '1', which is further connected to an earthing bar (1). + +1 Earthing bar in parallel with electrode in aqueous solution, foil or ball bearings + +NOTE – If the combined leakage of all wires is a problem, test each wire/pair in turn. + +**Figure B.2 – Connection detail for AC and lightning surge voltage test +(conductors to earth/ground)** + +![Schematic diagram of a termination module for AC and lightning surge voltage testing. The module has multiple pairs of conductors labeled xa1, xb1, xa2, xb2, ..., xan, xbn entering from the left. On the right side, the conductors are labeled ya1, yb1, ..., ya_n/2, yb_n/2. A note indicates that half the terminations are left unterminated. A voltage source is connected between the left and right conductor groups. The diagram is labeled K.065_FB.3.](8c348bf9c2c81b018017ae1d19506a9a_img.jpg) + +*Leave half the terminations unterminated* + +$n = \text{the number of pair terminations}$ + +K.065\_FB.3 + +Schematic diagram of a termination module for AC and lightning surge voltage testing. The module has multiple pairs of conductors labeled xa1, xb1, xa2, xb2, ..., xan, xbn entering from the left. On the right side, the conductors are labeled ya1, yb1, ..., ya\_n/2, yb\_n/2. A note indicates that half the terminations are left unterminated. A voltage source is connected between the left and right conductor groups. The diagram is labeled K.065\_FB.3. + +Test in the following sequences + +- $xa_1 - xb_1$ +- $xb_1 - xa_2$ +- $xa_2 - xb_2$ +- ⋮ +- $xa_n - xb_n$ etc. + +**Figure B.3 – Connection detail for AC and lightning surge voltage test (conductor to conductor)** + +![Circuit diagram for lightning surge coordination voltage test. It shows a 'Termination module' with two input conductors, xa and xb, and two output conductors, ya and yb. The output conductors are short-circuited. The input conductors are connected in series with a resistor 'R' and a 'Voltage source'.](69b7bd65e85cdef6fdd7fb0a8194257c_img.jpg) + +The diagram illustrates a circuit for lightning surge coordination voltage testing. At the top, a vertical rectangular block is labeled "Termination module". Two horizontal lines, labeled $x_a$ and $x_b$ , enter the module from the left. Two horizontal lines, labeled $y_a$ and $y_b$ , exit the module to the right. These two exit lines are connected by a vertical bar, with the text "Short circuit $y_a$ to $y_b$ " placed below it. On the left side, the input lines $x_a$ and $x_b$ are connected to a series combination of a resistor, represented by a rectangle labeled $R$ , and a voltage source, represented by a circle labeled "Voltage source". The entire series loop is connected back to the input lines $x_a$ and $x_b$ via a return path on the left. + +Circuit diagram for lightning surge coordination voltage test. It shows a 'Termination module' with two input conductors, xa and xb, and two output conductors, ya and yb. The output conductors are short-circuited. The input conductors are connected in series with a resistor 'R' and a 'Voltage source'. + +**Figure B.4 – Connection detail for lightning surge coordination voltage test (conductor to conductor) for SPDs with series elements** + +![Circuit diagram for lightning surge coordination voltage test. It shows a 'Termination module' with input conductors xa and xb, and output conductors ya and yb. Conductors ya and yb are short-circuited to a common return line. The return line passes through a 'Voltage source' and then splits: one path goes through a resistor labeled 'R' back to conductor xb, and the other path goes back to conductor xa. A text label indicates 'Short circuit ya and yb to generator return'.](11edb7fcedf09ac6a817f8d7b8c61eec_img.jpg) + +xa + +xb + +ya + +yb + +Short circuit ya and yb to generator return + +Termination module + +R + +Voltage source + +Circuit diagram for lightning surge coordination voltage test. It shows a 'Termination module' with input conductors xa and xb, and output conductors ya and yb. Conductors ya and yb are short-circuited to a common return line. The return line passes through a 'Voltage source' and then splits: one path goes through a resistor labeled 'R' back to conductor xb, and the other path goes back to conductor xa. A text label indicates 'Short circuit ya and yb to generator return'. + +**Figure B.5 – Connection detail for lightning surge coordination voltage test (conductors to earth) for SPDs with series elements** + +## Annex C + +### Connection details for current tests on termination modules + +(This annex forms an integral part of this Recommendation) + +![Diagram of connection details for connection resistance test on a termination module.](00504fc688ebcf131ccbeff94dfc9939_img.jpg) + +The diagram shows a central vertical rectangle labeled "Termination module". On the left side, there are horizontal lines representing terminals labeled xa1, xb1, xa2, xb2, and further down xan, xbn. On the right side, corresponding terminals are labeled ya1, yb1, and further down yan, ybn. A Milli-ohm meter is shown on the left, connected via a circuit loop that encompasses the terminals. A note at the bottom right of the diagram box states "n = the number of pair terminations". The diagram is labeled K.065\_FC.1 at the bottom right corner. + +Diagram of connection details for connection resistance test on a termination module. + +K.065\_FC.1 + +### Test sequence + +xa1 to ya1 +xb1 to yb1 +| +xan to yan +xbn to ybn + +**Figure C.1 – Connection detail for connection resistance test** + +![Diagram showing the connection detail for current test through a termination module. A central vertical rectangle labeled 'Termination module' has horizontal lines representing wire pairs entering from the left and exiting to the right. On the left, pairs are labeled xa1, xb1, xa2, xb2, and xan, xbn at the bottom. On the right, corresponding pairs are labeled ya1, yb1, and yan, ybn at the bottom. A circular 'Current generator' is connected via a wire loop that starts from the right side (connecting all y outputs) and returns to the left side (connecting all x inputs). A note at the bottom right states 'n = the number of pair terminations'. A small code 'K.065_FC.2' is in the bottom right corner.](692541e65db4dc852988ce77ebb60ce5_img.jpg) + +**Test sequence** + +$xa_1$ to $ya_1$ + $xb_1$ to $yb_1$ +| + $xa_n$ to $ya_n$ + $xb_n$ to $yb_n$ + +Diagram showing the connection detail for current test through a termination module. A central vertical rectangle labeled 'Termination module' has horizontal lines representing wire pairs entering from the left and exiting to the right. On the left, pairs are labeled xa1, xb1, xa2, xb2, and xan, xbn at the bottom. On the right, corresponding pairs are labeled ya1, yb1, and yan, ybn at the bottom. A circular 'Current generator' is connected via a wire loop that starts from the right side (connecting all y outputs) and returns to the left side (connecting all x inputs). A note at the bottom right states 'n = the number of pair terminations'. A small code 'K.065\_FC.2' is in the bottom right corner. + +**Figure C.2 – Connection detail for current test through the termination module** + +![Diagram of a current test setup. A 'Current generator' is connected to a 'Termination module with SPD'. The module has multiple pairs of conductors labeled xa1, xb1, xa2, xb2, ..., xa_n, xb_n on the left and ya1, yb1, ..., ya_n, yb_n on the right. The bottom of the module is connected to an 'Earth rail'. A note indicates 'n = the number of pair terminations'. The diagram is labeled K.065_FC.3.](08dce7ad4c512fdf0c0cde60415fade6_img.jpg) + +Diagram of a current test setup. A 'Current generator' is connected to a 'Termination module with SPD'. The module has multiple pairs of conductors labeled xa1, xb1, xa2, xb2, ..., xa\_n, xb\_n on the left and ya1, yb1, ..., ya\_n, yb\_n on the right. The bottom of the module is connected to an 'Earth rail'. A note indicates 'n = the number of pair terminations'. The diagram is labeled K.065\_FC.3. + +#### **Test sequence** + +- $xa_1 - 1$ +- $xb_1 - 1$ +- $xa_2 - 1$ +- | +- $xb_n - 1$ etc. + +- $ya_1 - 1$ +- $yb_1 - 1$ +- $ya_n - 1$ +- | +- $yb_n - 1$ etc. + +**Figure C.3 – Connection detail for current test +(through one conductor, with SPD)** + +![Schematic diagram of earthing bar current test connections. A 'Current generator' is connected between a common line side and an 'Earth rail'. The line side connects to a 'Termination module with SPD' through multiple pairs of conductors labeled xa1, xb1, xa2, xb2, ..., xa_n, xb_n. The module has corresponding output conductors labeled ya1, yb1, ..., ya_n, yb_n. A vertical line with dots between xb2 and xa_n indicates additional pairs. A note 'n - the number of pair terminations' is present. Below the diagram, the 'Test sequence' is listed as 'line side to ground' and 'cross-connect side to ground'. The diagram is labeled 'K.065 FC.4'.](7ae836e598020d937ed1478c2ef13025_img.jpg) + +xa1 + +ya1 + +xb1 + +yb1 + +xa2 + +xb2 + +Termination module with SPD + +n – the number of pair terminations + +xan + +yan + +xbn + +ybn + +Earth rail + +Current generator + +K.065 FC.4 + +**Test sequence** +line side to ground +cross-connect side to ground + +Schematic diagram of earthing bar current test connections. A 'Current generator' is connected between a common line side and an 'Earth rail'. The line side connects to a 'Termination module with SPD' through multiple pairs of conductors labeled xa1, xb1, xa2, xb2, ..., xa\_n, xb\_n. The module has corresponding output conductors labeled ya1, yb1, ..., ya\_n, yb\_n. A vertical line with dots between xb2 and xa\_n indicates additional pairs. A note 'n - the number of pair terminations' is present. Below the diagram, the 'Test sequence' is listed as 'line side to ground' and 'cross-connect side to ground'. The diagram is labeled 'K.065 FC.4'. + +**Figure C.4 – Connection detail for earthing bar current test +(through all pairs, SPD)** + +## Annex D + +### Test method for tests in aqueous solution + +(This annex forms an integral part of this Recommendation) + +![Diagram of immersion of UUT in a salt solution](7c07d25bb7b912053d0beb7ef9c41e91_img.jpg) + +The diagram shows a cross-section of a container filled with a salt solution. Inside the solution, a Unit Under Test (UUT) is positioned. To the right of the UUT, a vertical electrode is placed. +Key annotations in the diagram include: +- **Salt solution 5% by mass NaCl**: Indicates the liquid in the container. +- **Electrode**: Points to the vertical rod on the right. +- **UUT**: Points to the rectangular object on the left. +- **> 50 mm**: Vertical dimension from the liquid surface to the top edge of the UUT. +- **< 70 mm**: Horizontal dimension between the UUT and the electrode. +- **K.065\_FD.1**: Reference code at the bottom right of the drawing. + +Diagram of immersion of UUT in a salt solution + +**Figure D.1 – Immersion of UUT in a salt solution** + +## Annex E + +(This annex forms an integral part of this Recommendation) + +![Circuit diagram of a 10/350 μs current generator. It features a DC voltage source U_c in series with a switch and a capacitor C_1 = 1000 μF. This is followed by a parallel combination of a resistor R_1 = 1 Ω and a capacitor C_2 = 10 μF. The output stage consists of a series combination of a resistor R_2 = 0.3 Ω, an inductor L_1 = 3 μH, and a resistor R_3 = 0.7 Ω, leading to terminals g_1 and Return.](1142ba0197b158bb198186fe8baccc32_img.jpg) + +The diagram shows a circuit for a 10/350 $\mu\text{s}$ current generator. On the left, a DC voltage source $U_c$ is connected in series with a switch and a capacitor $C_1 = 1000 \mu\text{F}$ . This is followed by a parallel combination of a resistor $R_1 = 1 \Omega$ and a capacitor $C_2 = 10 \mu\text{F}$ . The output stage consists of a series combination of a resistor $R_2 = 0.3 \Omega$ , an inductor $L_1 = 3 \mu\text{H}$ , and a resistor $R_3 = 0.7 \Omega$ , leading to terminals $g_1$ and Return. + +Circuit diagram of a 10/350 μs current generator. It features a DC voltage source U\_c in series with a switch and a capacitor C\_1 = 1000 μF. This is followed by a parallel combination of a resistor R\_1 = 1 Ω and a capacitor C\_2 = 10 μF. The output stage consists of a series combination of a resistor R\_2 = 0.3 Ω, an inductor L\_1 = 3 μH, and a resistor R\_3 = 0.7 Ω, leading to terminals g\_1 and Return. + +NOTE – $L_1$ may need to be adjusted to give the correct rise time. + +**Figure E.1 – 10/350 $\mu\text{s}$ current generator** + +## Appendix I + +### Information on how to test termination modules with SPDs + +(This appendix does not form an integral part of this Recommendation) + +### I.1 Introduction + +This appendix documents how to test termination modules with SPDs. It shows how the current path may be different for termination modules without SPDs, compared with termination modules with SPDs. It describes the different effects that may occur for impulse currents, compared with mains power contact currents. It also describes the effect of the protector (GDT or SSA) operating and the effect of a fail-safe. + +Generally speaking, the termination modules (with and without SPDs) covered by this Recommendation can be used at a mid-point in the network or at a termination point, e.g., an MDF in a building. + +### I.2 Termination modules used in the access network + +Figure I.1 shows the current paths through a termination module without an SPD, compared with a termination module with an SPD, when the protector operates. The current path through a termination module/SPD when the protector does not operate, is the same as that for a termination module without an SPD. When the protector operates, the split of current between the current conducted to earth, compared with the current being conducted through the termination module/SPD, depends on the resistance to ground, $R$ , and the impedance to ground of the equipment to the right of the termination module. Therefore, the termination module/SPD should be able to conduct the full test current (lightning impulse and power frequency currents) through the termination module/SPD and both sides to ground via the SPD. + +![Figure I.1: Current paths for lightning surges and power frequency surges for termination modules and SPDs used in the access network. The diagram consists of two parts. The left part shows a termination module without an SPD or when the GDT does not operate. It features two IDC contacts at the top, a disconnect contact, a protection holder contact, a GDT (Gas Discharge Tube) connected to ground, and another protection holder contact at the bottom. A red arrow labeled 'current path' shows the flow from the left IDC contact, through the disconnect contact, to the GDT, and then to ground. The right part shows the same module when the GDT operates. In this case, the current path splits: one part goes through the GDT to ground, and the other part goes through a resistor labeled 'R' to ground. The red arrow labeled 'current path' shows the flow from the left IDC contact, through the disconnect contact, and then splitting between the GDT and the resistor R to ground.](1ad662a678c4f002de911d403f00de8e_img.jpg) + +Current path for a termination module without an SPD or when the GDT does not operate + +Current path when GDT operates + +K.065\_F1.1 + +Figure I.1: Current paths for lightning surges and power frequency surges for termination modules and SPDs used in the access network. The diagram consists of two parts. The left part shows a termination module without an SPD or when the GDT does not operate. It features two IDC contacts at the top, a disconnect contact, a protection holder contact, a GDT (Gas Discharge Tube) connected to ground, and another protection holder contact at the bottom. A red arrow labeled 'current path' shows the flow from the left IDC contact, through the disconnect contact, to the GDT, and then to ground. The right part shows the same module when the GDT operates. In this case, the current path splits: one part goes through the GDT to ground, and the other part goes through a resistor labeled 'R' to ground. The red arrow labeled 'current path' shows the flow from the left IDC contact, through the disconnect contact, and then splitting between the GDT and the resistor R to ground. + +NOTE – The amplitude of the current being conducted, after the GDT operates, will depend on the value of the resistance to ground $R$ . + +**Figure I.1 – Current paths for lightning surges and power frequency surges for termination modules and SPDs used in the access network** + +### **I.3 Termination modules used in MDFs in operator buildings and customer premises** + +Figure I.2 shows the possible paths for overcurrents for termination modules and SPDs installed on either the line or equipment side of the MDF. It also shows the different current paths depending on whether the protector operates. + +The important issue is that under some conditions, the full overcurrent can be conducted through the termination module/SPD. If an operator elects to use a termination module/SPD system which only meets the reduced requirements on the equipment side of the system, it is necessary to be certain that the full current will not be conducted in his application. + +Due to the various combinations of circumstances, it may be better for the manufacturer to design all termination module and SPD paths to conduct the full test current. The combinations of circumstances include: + +- the unit may be installed back to front; +- unknown equipment impedances; +- the possibility of thyristor protectors being installed between the primary protection and the equipment; +- the introduction of new equipment with a lower input impedance. + +For lightning surges, for the scenario shown in Figure I.2, it is assumed that the SPD will operate and the majority of the energy will be conducted to ground. One possibility would be to test the equipment side at 10% of the access side. This assumes a 10-ohm to ground path in the equipment (very worst case) and a one-ohm to ground in the MDF. If the MDF protection system were tested for the current path shown, there would need to be a procedure to ensure that it is not installed back to front. + +For mains power contact, for the scenario in Figure I.2, it is assumed that the SPD will operate and the majority of the energy will be conducted to ground. One possibility would be to test the jumper side only using the 160, 300, 600 and 1000 ohm test resistors. + +It is possible in some installations to end up with SPDs in both blocks, only in the access side or only in the equipment side, due to a mixture of solder tag and IDC MDF blocks on the access side of the MDF. The scenario showing the SPD fitted on the equipment side is shown in Figure I.2. In this case, it would be reasonable to specify the full test current through the protection system and both sides to ground via the SPD. + +From a termination module/SPD manufacturers point of view, it is probably better to design their product to withstand the lightning surge current both through the termination module/SPD and to ground via the SPD. It may also be best to design the termination module to be used with and without the SPD installed. + +![Diagram (a) showing current paths for lightning surges and power frequency surges for termination modules used in an MDF. The diagram is divided into 'MDF access side' and 'MDF equipment side'. On the access side, there are two IDC (Interface Disconnection Contacts) and a GDT (Gas Discharge Tube) connected to ground. On the equipment side, there are two more IDCs and an 'equipment' block with a 'Note'. A red line labeled 'Current path' shows the flow of current from the access side, through the first IDC, then through the GDT to ground. Another red line shows current flowing from the equipment side, through the second IDC, then through the first IDC on the access side, and finally through the GDT to ground. Labels include 'disconnect contacts', 'Holder contacts', and 'Note'.](77959075c823bb5169480d7b8ff82a63_img.jpg) + +Diagram (a) showing current paths for lightning surges and power frequency surges for termination modules used in an MDF. The diagram is divided into 'MDF access side' and 'MDF equipment side'. On the access side, there are two IDC (Interface Disconnection Contacts) and a GDT (Gas Discharge Tube) connected to ground. On the equipment side, there are two more IDCs and an 'equipment' block with a 'Note'. A red line labeled 'Current path' shows the flow of current from the access side, through the first IDC, then through the GDT to ground. Another red line shows current flowing from the equipment side, through the second IDC, then through the first IDC on the access side, and finally through the GDT to ground. Labels include 'disconnect contacts', 'Holder contacts', and 'Note'. + +a) Protector on line side of MDF, protector does not operate + +![Diagram (b) showing current paths for lightning surges and power frequency surges for termination modules used in an MDF. The diagram is divided into 'MDF access side' and 'MDF equipment side'. On the access side, there are two IDC (Interface Disconnection Contacts) and a GDT (Gas Discharge Tube) connected to ground. On the equipment side, there are two more IDCs and an 'equipment' block with a 'Note'. A red line labeled 'Current path' shows the flow of current from the access side, through the first IDC, then through the GDT to ground. Another red line shows current flowing from the equipment side, through the second IDC, then through the first IDC on the access side, and finally through the GDT to ground. Labels include 'disconnect contacts', 'Holder contacts', and 'Note'. Currents I1 and I2 are indicated.](47a7beddcb8a1b7abdca746967e32bb4_img.jpg) + +Diagram (b) showing current paths for lightning surges and power frequency surges for termination modules used in an MDF. The diagram is divided into 'MDF access side' and 'MDF equipment side'. On the access side, there are two IDC (Interface Disconnection Contacts) and a GDT (Gas Discharge Tube) connected to ground. On the equipment side, there are two more IDCs and an 'equipment' block with a 'Note'. A red line labeled 'Current path' shows the flow of current from the access side, through the first IDC, then through the GDT to ground. Another red line shows current flowing from the equipment side, through the second IDC, then through the first IDC on the access side, and finally through the GDT to ground. Labels include 'disconnect contacts', 'Holder contacts', and 'Note'. Currents I1 and I2 are indicated. + +b) Protector on line side of MDF, protector does operate + +![Diagram (c) showing current paths for lightning surges and power frequency surges for termination modules used in an MDF. The diagram is divided into 'MDF access side' and 'MDF equipment side'. On the access side, there are two IDC (Interface Disconnection Contacts). On the equipment side, there are two more IDCs and a GDT (Gas Discharge Tube) connected to ground. An 'equipment' block with a 'Note' is also on the equipment side. A red line labeled 'Current path' shows the flow of current from the access side, through the first IDC, then through the second IDC on the equipment side, and finally through the GDT to ground. Another red line shows current flowing from the equipment side, through the second IDC, then through the first IDC on the access side, and finally through the GDT to ground. Labels include 'disconnect contacts', 'Holder contacts', and 'Note'. Currents I1 and I2 are indicated. The text 'K.065_F1.2' is in the bottom right corner.](b58cedaf15ad4f0edee5621820865ccc_img.jpg) + +Diagram (c) showing current paths for lightning surges and power frequency surges for termination modules used in an MDF. The diagram is divided into 'MDF access side' and 'MDF equipment side'. On the access side, there are two IDC (Interface Disconnection Contacts). On the equipment side, there are two more IDCs and a GDT (Gas Discharge Tube) connected to ground. An 'equipment' block with a 'Note' is also on the equipment side. A red line labeled 'Current path' shows the flow of current from the access side, through the first IDC, then through the second IDC on the equipment side, and finally through the GDT to ground. Another red line shows current flowing from the equipment side, through the second IDC, then through the first IDC on the access side, and finally through the GDT to ground. Labels include 'disconnect contacts', 'Holder contacts', and 'Note'. Currents I1 and I2 are indicated. The text 'K.065\_F1.2' is in the bottom right corner. + +c) Protector on equipment side of MDF, protector does operate + +NOTE – Termination modules/SPDs in the equipment are covered by the relevant equipment Recommendations. + +**Figure I.2 – Current paths for lightning surges and power frequency surges for termination modules used in an MDF** + +## Appendix II + +## Application + +(This appendix does not form an integral part of this Recommendation) + +### II.1 Environment + +Three environments have been defined to determine the test methods for termination modules and SPDs. These are: + +- underground where the termination module/protection unit may occasionally be flooded; +- humid (semi-controlled) environments; +- controlled environments. + +### II.2 Termination module and SPD types + +Two types of termination modules and SPDs are considered in this Recommendation: + +- filled; +- dry. + +A dry termination module or SPD is considered suitable for use in controlled environments only, while a filled termination module, or SPD, is suitable for use in both the uncontrolled and underground environments. The test severity is based on the intended environment and termination module or protection unit type. + +### II.3 Dry termination module and SPD tests + +As a dry termination module or SPD is considered suitable for use in a controlled environment, the insulation resistance and voltage breakdown tests are performed after wrapping the unit in aluminium foil. + +### II.4 Filled termination module and SPD tests + +For termination modules and SPDs considered suitable for use in a wet or humid environment, the insulation resistance and voltage breakdown tests are performed with the unit immersed in a salt solution. + +### II.5 Application + +Filled termination modules and SPDs are suitable for all applications. Dry termination modules and SPDs perform best when used in a controlled environment. Their use in semi-controlled environments, where they will be exposed to high humidity, and underground, where they may be flooded, may reduce their reliability and their useful lifetime. + +## Bibliography + +- [b-ITU-T K.20] Recommendation ITU-T K.20 (2008), *Resistibility of telecommunication equipment installed in a telecommunications centre to overvoltages and overcurrents.* +- [b-ITU-T K.21] Recommendation ITU-T K.21 (2008), *Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents.* +- [b-ITU-T K.45] Recommendation ITU-T K.45 (2008), *Resistibility of telecommunication equipment installed in the access and trunk networks to overvoltages and overcurrents.* +- [b-IEC 61663-2] IEC P-IEC 61663-2 ed1.0 (2001), *Lightning protection – Telecommunication lines – Part 2: Lines using metallic conductors.* +- [b-IEC Electropedia] International Electrotechnical Commission, *electropedia.* +<> + + + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|---------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.76-202208-I_PDF-E/raw.md b/marked/K/T-REC-K.76-202208-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..ab53ab1cdc10db9442d9755e96d88abaec57d3d1 --- /dev/null +++ b/marked/K/T-REC-K.76-202208-I_PDF-E/raw.md @@ -0,0 +1,500 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.76** + +(08/2022) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Electromagnetic compatibility requirements for +DC power ports of telecommunication network +equipment in frequencies below 150 kHz** + +Recommendation ITU-T K.76 + + + +# Recommendation ITU-T K.76 + +# Electromagnetic compatibility requirements for DC power ports of telecommunication network equipment in the frequencies below 150 kHz + +## Summary + +Recommendation ITU-T K.76 specifies conducted emissions requirements for DC power ports of telecommunication network equipment in frequencies below 150 kHz. Furthermore, an immunity requirement specific to power ports of telecommunication network equipment with analogue voice interfaces is also defined. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.76 | 2008-07-07 | 5 | 11.1002/1000/9413 | +| 2.0 | ITU-T K.76 | 2022-08-13 | 5 | 11.1002/1000/15037 | + +## Keywords + +Below 150 kHz, conducted emissions, conducted immunity, electromagnetic compatibility, low frequency, performance criteria. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +# FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2022 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|-----|-------------------------------------------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 3.1 | Terms defined elsewhere ..... | 2 | +| 4 | Abbreviations and acronyms ..... | 2 | +| 5 | Conventions ..... | 2 | +| 6 | Emission on DC power port in frequencies below 150 kHz ..... | 2 | +| 6.1 | Equipment configuration ..... | 3 | +| 6.2 | Emission requirements ..... | 3 | +| 7 | Immunity requirements..... | 5 | +| 7.1 | Test level ..... | 5 | +| 7.2 | Test set-up ..... | 6 | +| 7.3 | Method of measurement ..... | 6 | +| 7.4 | Performance criteria ..... | 7 | +| | Annex A – Verification of measurement network defined in clause 6.2.1.2 ..... | 8 | +| | Appendix I – Example of disturbances at low frequency ..... | 9 | +| I.1 | Audible noise caused by disturbance from rectifier ..... | 9 | +| I.2 | Audible noise in telephone services provided from a central office ..... | 9 | +| I.3 | Trouble in LAN system ..... | 10 | +| | Bibliography..... | 11 | + +# **Introduction** + +This Recommendation complements the electromagnetic compatibility requirements for telecommunication network equipment contained in [ITU-T K.136] and [ITU-T K.137] by specifying requirements in frequencies below 150 kHz. + +Telecommunication network equipment can produce disturbances to other equipment or can be susceptible to the electromagnetic phenomena in the frequencies below 150 kHz. + +A necessity to analyse these frequencies was highlighted considering the influence that very low frequency disturbances have on analogue voice communication. + +# Recommendation ITU-T K.76 + +# Electromagnetic compatibility requirements for DC power ports of telecommunication network equipment in the frequencies below 150 kHz + +# 1 Scope + +This Recommendation considers continuous electromagnetic phenomena applicable on direct current (DC) power ports of telecommunication network equipment in frequencies below 150 kHz. Electromagnetic phenomena above 150 kHz are covered by other specific product family Recommendations such as [ITU-T K.136] and [ITU-T K.137]. Impulsive low frequency phenomena are considered in other K-series Recommendations. + +Both the emissions and the immunity requirements in frequencies below 150 kHz are taken into consideration in this Recommendation. + +This Recommendation defines test set-ups, measurement methods, emission limits and immunity test levels for power ports of telecommunication network equipment. + +This Recommendation applies to all types of telecommunication network equipment. Due to the nature of the interference, the immunity test is applicable only to equipment having an analogue voice interface that could be influenced by disturbing signals in the voice frequency range. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.136] Recommendation ITU-T K.136 (2018), *Electromagnetic compatibility requirements for radio telecommunication equipment*. +- [ITU-T K.137] Recommendation ITU-T K.137 (2022), *Electromagnetic compatibility requirements and measurement methods for wireline telecommunication network equipment*. +- [IEC CISPR 16-1-1] IEC CISPR 16-1-1:2019, *Specification for radio disturbance and immunity measuring apparatus and methods – Part 1-1: Radio disturbance and immunity measuring apparatus – Measuring apparatus*. +- [IEC CISPR 16-1-2] IEC CISPR 16-1-2:2014 + AMD1:2017, *Specification for radio disturbance and immunity measuring apparatus and methods – Part 1-2: Radio disturbance and immunity measuring apparatus – Coupling devices for conducted disturbance measurements*. +- [IEC CISPR 16-2-1] IEC CISPR 16-2-1:2014 + AMD1:2017, *Specification for radio disturbance and immunity measuring apparatus and methods – Part 2-1: Methods of measurement of disturbances and immunity – Conducted disturbance measurements*. +- [IEC CISPR 32] IEC CISPR 32:2015 + AMD1:2019, *Electromagnetic compatibility of multimedia equipment – Emission requirements*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following term defined elsewhere: + +**3.1.1 continuous disturbance** [b-IEC 60050-161], (161-02-11): Electromagnetic disturbance the effect of which on a particular device or equipment cannot be resolved into a succession of distinct effects. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 fully populated equipment:** Equipment designed to provide housing ('slots') for a number of different functional modules (line cards, etc.), configured such that the full capacity (i.e., all 'slots') is populated with modules in a manner representative of intended use. + +**3.2.2 nominal current:** The DC current consumption of a fully populated equipment powered at the nominal DC voltage when the equipment is operated in a manner representative of intended use. + +**3.2.3 nominal voltage:** The value of the voltage that designates the type of supply declared by the manufacturer. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|-------------------------------------| +| ADN | Artificial Direct current Network | +| DC | Direct Current | +| DSU | Data Service Unit | +| EUT | Equipment Under Test | +| ISDN | Integrated Services Digital Network | +| LAN | Local Area Network | +| NM | Normal-Mode | +| RMS | Root Mean Square | +| SW | Switching Equipment | + +# 5 Conventions + +None. + +# 6 Emission on DC power port in frequencies below 150 kHz + +The electromagnetic emissions at low frequency in telecommunication network equipment are mainly due to the power units. Considering the wavelength of the disturbances in these frequencies, the radiated emissions are impractical (several hundred meters of cable length should be used) and therefore only conducted emission requirements are defined. Experience has been reported from telecommunication installations that emissions at low frequency from power ports can cause trouble in telecommunication installations (see Appendix I). + +## 6.1 Equipment configuration + +During the measurements, the telecommunication network equipment shall be powered at nominal voltage, operated at rated load conditions and have achieved a steady state (such that any transients on the current consumption associated with equipment power-up can be neglected). + +If the power consumption of the equipment changes significantly from one operational state to another, the equipment shall be tested in each operational state to determine the highest value of emission. + +The equipment shall be configured in a manner representative of intended use and exercised accordingly. + +Detailed equipment test conditions, for different types of products, are reported in [ITU-T K.136] and [ITU-T K.137]. + +## 6.2 Emission requirements + +The emissions from DC power ports are divided into the following two frequency ranges: + +- Range 1: from 25 Hz to 20 kHz (narrow-band noise). +- Range 2: from 20 kHz to 150 kHz. + +### 6.2.1 Emissions in range 1 + +#### 6.2.1.1 Limits + +The maximum level of noise emitted into the DC power supply system of the telecommunication network equipment is shown in Figure 1. + +The values shown in Figure 1 refer to the bandwidths given in Table 1. + +**Table 1 – Resolution bandwidths versus frequency range** + +| Frequency range | Resolution bandwidth | +|--------------------|----------------------| +| 25 Hz to 10 kHz | 10 Hz | +| > 10 kHz to 20 kHz | 200 Hz or 300 Hz | + +![Figure 1: Maximum levels of narrow-band noise. A log-log plot showing noise limits in dBm and dBuV versus frequency f (Hz). The plot shows a piecewise linear limit line with three segments: -21 dBm from 25 Hz to 150 Hz, a downward slope from -21 dBm at 150 Hz to -40 dBm at 1000 Hz, and a horizontal segment at -40 dBm from 1000 Hz to 20000 Hz. A dashed horizontal line is also shown at -21 dBm.](f09dce76b09a6f332810e5193cc39d56_img.jpg) + +| f (Hz) | dBm | dBuV | +|--------|-----|------| +| 25 | -21 | 86 | +| 150 | -21 | 86 | +| 1000 | -40 | 67 | +| 20000 | -40 | 67 | + +Figure 1: Maximum levels of narrow-band noise. A log-log plot showing noise limits in dBm and dBuV versus frequency f (Hz). The plot shows a piecewise linear limit line with three segments: -21 dBm from 25 Hz to 150 Hz, a downward slope from -21 dBm at 150 Hz to -40 dBm at 1000 Hz, and a horizontal segment at -40 dBm from 1000 Hz to 20000 Hz. A dashed horizontal line is also shown at -21 dBm. + +**Figure 1 – Maximum levels of narrow-band noise** + +### 6.2.1.2 Measurement methods + +The equipment under test (EUT) shall be connected to the DC power supply through an artificial network to provide defined impedance across the EUT at the point of measurement and to provide isolation from the noise on the DC power supply lines. This artificial network is referred to hereafter as the artificial DC network (ADN) and is displayed in Figure 3. + +The measurement shall be made with a spectrum analyser or a receiver having the bandwidths shown in Table 1 for the relevant frequency range. + +The measurement circuit shall be as shown in Figure 2. The measurement circuit shall be verified as described in Annex A. + +The measurement shall be performed at three values of the powering voltage: the minimum, nominal and maximum of the normal service voltage range. + +![Figure 2 – Measuring circuit for emitted narrow-band noise](7801d00a216dc4dc8a7d210dcb5fe3c5_img.jpg) + +``` + + graph LR + PS_pos("+") --- ADN + PS_neg("-") --- ADN + ADN --- Zc + Zc --- EUT + ADN --- EUT + subgraph Measurement + Zc --- Zm + Zm --- SA("Spectrum analyser") + end + +``` + +$Z_m = 50 \text{ \Omega}$ (internal instrument impedance) + $Z_c \ll Z_m$ at all measured frequencies. + +**Figure 2 – Measuring circuit for emitted narrow-band noise** + +Figure 2 – Measuring circuit for emitted narrow-band noise + +![Figure 3 – Artificial DC network](f519a5be118c846f631c992412353fb9_img.jpg) + +``` + + graph LR + In_neg("-") --- R --- L --- Out_neg + In_pos("+") --- C(">10 mF") --- R + In_pos --- Out_pos + C --- Ground + +``` + +**Figure 3 – Artificial DC network** + +Figure 3 – Artificial DC network + +Note that the ADN can be designed for telecommunication network equipment considering the nominal value of the DC voltage. Values for the resistance, R, and inductance, L, shown in Figure 3 are as follows: + +$$R \le \frac{1}{I_m}$$ + +where: + +$I_m$ is the nominal current drawn at the nominal DC operating voltage + +$L = 15 \text{ \mu H} +/- 10\% @ 10 \text{ kHz}$ + +### 6.2.2 Emissions in range 2 + +#### 6.2.2.1 Limits + +The maximum level of noise re-injected into the DC power supply system of the telecommunication network equipment is shown in Table 2. + +4 Rec. ITU-T K.76 (08/2022) + +**Table 2 – Noise emission limits on DC power ports** + +| Frequency range | Limit
[dB $\mu$ V] | +|-------------------|-----------------------| +| | Quasi-peak | +| 20 kHz to 150 kHz | 79 | + +#### 6.2.2.2 Measurement methods + +The measurement shall be made with a spectrum analyser or a receiver in line with the requirements of [IEC CISPR 16-1-1]. + +The measuring methods shall be those specified for the mains interface in [IEC CISPR 32] or [IEC CISPR 16-2-1]. + +The EUT shall be connected to the DC power supply through an artificial network to provide defined impedance across the EUT at the point of measurement and to provide isolation from the noise on the DC power supply lines. + +The artificial network to be used is the 9 kHz to 150 kHz: ( $50\ \Omega$ // $50\ \mu\text{H} + 5\ \Omega$ ) artificial mains V-network described in [IEC CISPR 16-1-2]. + +# 7 Immunity requirements + +Telecommunication network equipment with analogue voice interfaces can be sensitive to low frequency noise present on the DC power port, as this noise can be transferred to the analogue voice interface, where it presents itself as an audible noise that disturbs the voice conversation. Therefore, immunity requirements are only defined for DC power port and only in the frequency range 25 Hz to 20 kHz. + +## 7.1 Test level + +The telecommunication network equipment shall meet its specified performance criteria when the narrow-band noise is injected at the DC input port. + +The root mean square (RMS) value of the injected noise current shall generally be 5% of the DC current level drawn by the equipment, but the injected noise voltage shall not exceed the level shown in Figure 4. + +![Figure 4: Immunity level of narrow-band noise at DC power port. A log-log plot showing the immunity level in dBm (left y-axis, -40 to 0) and mV (right y-axis, 2.24 to 224) versus frequency f (Hz) (x-axis, 10 to 20000). The curve is constant at -13 dBm (50 mV) from 25 Hz to 100 Hz, then decreases linearly to -30 dBm (7.07 mV) at 1000 Hz, and remains constant at -30 dBm (7.07 mV) up to 20000 Hz. The plot is labeled K.76(22)_F04.](36ac3e730a00d3f42d3400f5709f641a_img.jpg) + +Figure 4: Immunity level of narrow-band noise at DC power port. A log-log plot showing the immunity level in dBm (left y-axis, -40 to 0) and mV (right y-axis, 2.24 to 224) versus frequency f (Hz) (x-axis, 10 to 20000). The curve is constant at -13 dBm (50 mV) from 25 Hz to 100 Hz, then decreases linearly to -30 dBm (7.07 mV) at 1000 Hz, and remains constant at -30 dBm (7.07 mV) up to 20000 Hz. The plot is labeled K.76(22)\_F04. + +**Figure 4 – Immunity level of narrow-band noise at DC power port** + +## 7.2 Test set-up + +During the measurement, the telecommunication network equipment shall be powered at the nominal voltage and operated at rated load conditions. + +The equipment shall be configured in a manner representative of intended use and exercised accordingly. + +Detailed equipment test conditions for different type of products are reported in [ITU-T K.136] and [ITU-T K.137]. + +## 7.3 Method of measurement + +The interference signal is injected into the DC power line using the circuit reported in Figure 5. + +![Figure 5: Test arrangement for immunity test. A block diagram showing a DC source connected to a DC power line. A signal generator is connected to an amplifier, which is connected to a coupler. The coupler is connected to the DC power line. The DC power line is also connected to a capacitor (>100uF) and a ground. The DC power line is connected to the EUT (Equipment Under Test). The EUT is connected to a noise meter. The DC power line is also connected to an oscilloscope and a 50 Ω resistor. The plot is labeled K.76(22)_F05.](78ffccd66df9bafd96e3e081110d09dd_img.jpg) + +Figure 5: Test arrangement for immunity test. A block diagram showing a DC source connected to a DC power line. A signal generator is connected to an amplifier, which is connected to a coupler. The coupler is connected to the DC power line. The DC power line is also connected to a capacitor (>100uF) and a ground. The DC power line is connected to the EUT (Equipment Under Test). The EUT is connected to a noise meter. The DC power line is also connected to an oscilloscope and a 50 Ω resistor. The plot is labeled K.76(22)\_F05. + +NOTE 1 – $Z_c \ll 50 \Omega$ at all measured frequencies. + +NOTE 2 – The oscilloscope can be replaced by a spectrum analyser. + +NOTE 3 – The $50 \Omega$ shall be the input impedance of the measurement instrument (oscilloscope or spectrum analyser). + +**Figure 5 – Test arrangement for immunity test** + +Where the frequency is swept incrementally, the step size shall not exceed 1% of the preceding frequency value. The dwell time at each frequency shall not be less than the time necessary for the EUT to be exercised and to respond, but shall in no case be less than 1 s. + +The generator shall be calibrated initially over the whole frequency range by connecting the transformer to a 0.5 $\Omega$ resistor and checking the voltage over the 0.5 $\Omega$ resistor. + +Calibration procedure: + +- 1) Set the signal generator to the lowest test frequency. +- 2) Increase the applied signal until the oscilloscope indicates the voltage level corresponding to the maximum required power level specified for the limit. +- 3) Record the setting of the signal source. +- 4) Scan to test the required frequency range and record the signal source setting needed to maintain the required power level. The frequency step size shall not exceed 1% of the preceding frequency value. + +Compliance is achieved when the specified performance criteria are met when either of the following conditions is reached: + +- The maximum noise voltage value (i.e., as presented on Figure 4); or +- The RMS of the injected noise current reaches 5% of the DC current level drawn by the equipment. + +The level of the disturbance signal shall be controlled with a spectrum analyser having the bandwidths shown in Table 1 for the relevant frequency ranges. + +## 7.4 Performance criteria + +During the test, the telecommunication network equipment has to fulfil performance criterion A reported below. + +Special requirements for analogue voice frequency signal ports are as follows. + +The performance of the equipment shall be verified by measuring the audio signal break-through (demodulated 1 kHz) on the signal port during continuous exposure, in both signal path directions, covering both analogue-to-digital conversion, and digital-to-analogue conversion. + +The connection must be maintained throughout testing: + +- a) During a sweep over the entire frequency range, the noise level measured at each two-wire analogue port at 600 $\Omega$ (ignoring the normal impedance of the port for practical reasons) must be less than $-40$ dBm. +- b) The measurement shall be done selectively with a bandwidth $\leq 100$ Hz at 1 kHz. + +### Performance criterion A + +The telecommunication network equipment shall continue to operate as intended. No degradation of performance or loss of function is allowed below a performance level specified by the manufacturer, when the equipment is used as intended. In some cases, the performance level may be replaced by a permissible loss of performance. If the minimum performance level or the permissible performance loss is not specified by the manufacturer, then either of these may be derived from the product description and documentation, and what the user may reasonably expect from the equipment, if used as intended. + +# Annex A + +## Verification of measurement network defined in clause 6.2.1.2 + +(This annex forms an integral part of this Recommendation.) + +The measurement test bench defined in clause 6.2.1.2 shall be verified to determine whether an attenuation is introduced by the decoupling capacitor $Z_c$ . The verification of the test bench shall be done on a 50 Ohm system as described in Figure A.1. + +The verification shall be performed connecting a signal generator at the port of the measurement network where the EUT will be connected as described in Figure A.1. Then, the signal generator shall be set to generate a test voltage of $X$ dB $\mu$ V in the frequency range 20 Hz to 20 kHz and the reading on the measurement receiver shall be of $X$ dB $\mu$ V $\pm 2\%$ in the entire frequency range. If the reading of the measurement receiver is outside the tolerance of $\pm 2\%$ in respect to the generator signal, then the attenuation (i.e., insertion loss) of the network shall be determined with the following formula: + +$$IL = X - Y$$ + +Where: + +IL: Insertion loss + +X: Voltage level at the generator port (in dB $\mu$ V) + +Y: Voltage level at the measurement receiver port (in dB $\mu$ V) + +The attenuation of the network shall be considered in the emission of the EUT measurements and the IL values shall be added to the EUT measured values to determine the compliance with the limits of Figure 1. + +![Circuit diagram of the test bench for verification of Zc insertion losses. It shows a box labeled 'ADN' containing a resistor 'R' and an inductor 'L' in series. To the left of the box, a capacitor labeled '>10 mF' is connected between the top and bottom lines, with the bottom line connected to ground. To the right of the box, the top line connects to a node labeled 'Zc'. From this node, a voltmeter 'V' and a 50 Ohm resistor are connected in parallel to the bottom line. The bottom line also connects to another node, from which a generator 'G' and a 50 Ohm resistor are connected in parallel to the top line. The label 'K.76(22)_FA.1' is at the bottom right of the diagram.](704082cc3e11776bda29595c76411362_img.jpg) + +Circuit diagram of the test bench for verification of Zc insertion losses. It shows a box labeled 'ADN' containing a resistor 'R' and an inductor 'L' in series. To the left of the box, a capacitor labeled '>10 mF' is connected between the top and bottom lines, with the bottom line connected to ground. To the right of the box, the top line connects to a node labeled 'Zc'. From this node, a voltmeter 'V' and a 50 Ohm resistor are connected in parallel to the bottom line. The bottom line also connects to another node, from which a generator 'G' and a 50 Ohm resistor are connected in parallel to the top line. The label 'K.76(22)\_FA.1' is at the bottom right of the diagram. + +$Z_c \ll 50 \Omega$ + +V: Measuring equipment + +G: Generator for frequency range 20 Hz – 20 KHz + +**Figure A.1 – Test bench for verification of $Z_c$ insertion losses** + +# Appendix I + +## Example of disturbances at low frequency + +(This appendix does not form an integral part of this Recommendation.) + +This appendix reports some examples of interference due to a signal at a frequency below 150 kHz in a telecommunication installation. + +- The first example is noise generated by a power rectifier that injects noise into the DC distribution, and this noise can generate disturbance on an audio signal in the terminal equipment. +- The second example shows how the noise generated by a lighting system can induce disturbances in a telecommunication network. + +## I.1 Audible noise caused by disturbance from rectifier + +The example of the audible noise caused by interference from a rectifier is shown in Figure I.1. The common-mode noise produced by the rectifier propagates to equipment B on the DC power feeding cable, then it propagates toward the subscriber line through equipment B. Common-mode noise on the telecommunication cable connected to equipment A is induced by magnetic or capacitive coupling. The common-mode noise becomes normal-mode noise by the imbalance of equipment A. By detecting the envelope of the noise, this normal-mode noise is converted to audible noise at the terminal in equipment A, then it propagates to the terminal equipment and is recognized as acoustic noise. + +Measurement results demonstrate that the main spectrum component of the noise is around 50 kHz and its envelope has an audible frequency component. + +![Diagram illustrating the configuration of trouble caused by interference from a rectifier. A rectifier is connected to Equip. B via a DC power feeding cable. Common-mode (CM) noise propagates from the rectifier through Equip. B into the subscriber line. This CM-noise is coupled from the subscriber line to another subscriber line connected to Equip. A. At Equip. A, the CM-noise is converted to normal-mode (NM) noise due to equipment imbalance. This NM-noise then propagates to the terminal equipment, resulting in acoustic noise. The diagram includes labels for 'Acoustic noise', 'NM-noise', 'Subscriber line', 'MDF', 'Equip. A', 'Mode conversion (Envelope detected)', 'Equip. B', 'DC power feeding', and 'Rectifier'. A reference code 'K.76(22)_FI.1' is shown in the bottom right corner of the diagram area.](c67d21fb3d9042e88cdc669f071b4e7c_img.jpg) + +Diagram illustrating the configuration of trouble caused by interference from a rectifier. A rectifier is connected to Equip. B via a DC power feeding cable. Common-mode (CM) noise propagates from the rectifier through Equip. B into the subscriber line. This CM-noise is coupled from the subscriber line to another subscriber line connected to Equip. A. At Equip. A, the CM-noise is converted to normal-mode (NM) noise due to equipment imbalance. This NM-noise then propagates to the terminal equipment, resulting in acoustic noise. The diagram includes labels for 'Acoustic noise', 'NM-noise', 'Subscriber line', 'MDF', 'Equip. A', 'Mode conversion (Envelope detected)', 'Equip. B', 'DC power feeding', and 'Rectifier'. A reference code 'K.76(22)\_FI.1' is shown in the bottom right corner of the diagram area. + +Figure I.1 – Configuration of trouble caused by interference from rectifier + +## I.2 Audible noise in telephone services provided from a central office + +Figure I.2 illustrates an example of the trouble caused by power electronics apparatus. Noise is generated in a fluorescent light using inverter technology. The noise propagates through the power line connected to the fluorescent light and flows into the telecommunication cable via telecommunication terminal equipment. + +In this case, the main spectrum component of the noise is around 80 kHz. Now the noise is not only converted into audible noise at the terminal equipment, but also at the switching equipment. Furthermore, similar disturbance occurs in a lot of terminal equipment, which is connected to different pairs in the same cable, because the noise is induced in the lines of the cable by electromagnetic or capacitive coupling. + +![Diagram illustrating the propagation of noise from a fluorescent light to a telecommunication line. A fluorescent light fixture is shown at the top with an arrow labeled 'Propagation of noise'. Below it, a 'Terminal equipment' (a telephone) is connected to a 'Power line' and a 'Telecommunication line'. The 'Telecommunication line' is connected to a 'Telecommunication cable' which is coupled to a 'SW' (switch). Another 'Terminal equipment' (a computer) is connected to the 'Telecommunication cable'. The diagram shows the noise propagating from the fluorescent light, through the power line, and into the telecommunication cable via coupling. The label 'K.76(22)_FI.2' is at the bottom right.](fa859e4e468bfb2710a94527f2c504af_img.jpg) + +Diagram illustrating the propagation of noise from a fluorescent light to a telecommunication line. A fluorescent light fixture is shown at the top with an arrow labeled 'Propagation of noise'. Below it, a 'Terminal equipment' (a telephone) is connected to a 'Power line' and a 'Telecommunication line'. The 'Telecommunication line' is connected to a 'Telecommunication cable' which is coupled to a 'SW' (switch). Another 'Terminal equipment' (a computer) is connected to the 'Telecommunication cable'. The diagram shows the noise propagating from the fluorescent light, through the power line, and into the telecommunication cable via coupling. The label 'K.76(22)\_FI.2' is at the bottom right. + +**Figure I.2 – Propagation of noise from fluorescent light** + +## I.3 Trouble in LAN system + +Figure I.3 shows the configuration of a local area network (LAN) installed in a ski venue where disturbance caused by a ski lift occurred. A router is connected to the integrated services digital network (ISDN) that is provided from a telecommunication centre via a data service unit (DSU). The router stops functioning when the lift is running. + +In this case, the noise is produced by the lift motor. Then the noise flows into a power line and propagates into the router. The measured voltage between the neutral line and earthing electrode shows a magnitude of the noise of about 100 V peak-to-peak with a main spectrum component of about 50 kHz, and a burst frequency of about 5 kHz. + +From this measurement, it is found that this noise creates a disturbance in the router's power line and causes the malfunction. + +![Diagram illustrating the LAN configuration in a ski venue. A 'Central office' is connected to a 'DSU' via an 'ISDN line'. The 'DSU' is connected to a 'Connector'. The 'Connector' is connected to a 'Server' and a 'Router'. The 'Router' is connected to a 'Power' source and a 'Power distribution' unit. The 'Power distribution' unit is connected to a 'Lift motor'. The diagram shows the flow of noise from the 'Lift motor' through the 'Power distribution' unit and into the 'Router'. The label 'K.76(22)_FI.3' is at the bottom right.](41a438d7e4adc17c3a4005e7c9500091_img.jpg) + +Diagram illustrating the LAN configuration in a ski venue. A 'Central office' is connected to a 'DSU' via an 'ISDN line'. The 'DSU' is connected to a 'Connector'. The 'Connector' is connected to a 'Server' and a 'Router'. The 'Router' is connected to a 'Power' source and a 'Power distribution' unit. The 'Power distribution' unit is connected to a 'Lift motor'. The diagram shows the flow of noise from the 'Lift motor' through the 'Power distribution' unit and into the 'Router'. The label 'K.76(22)\_FI.3' is at the bottom right. + +**Figure I.3 – LAN configuration** + +# Bibliography + +- [b-ETSI EN 300 132-2] ETSI EN 300 132-2 V.2.7.1 (2022), *Environmental Engineering (EE); Power supply interface at the input of Information and Communication Technology equipment; Part 2: –48 V Direct Current (DC)*. +[https://www.etsi.org/deliver/etsi\\_en/300100\\_300199/30013202/02.07.01\\_60/en\\_30013202v020701p.pdf](https://www.etsi.org/deliver/etsi_en/300100_300199/30013202/02.07.01_60/en_30013202v020701p.pdf) +- [b-IEC 60050-161] IEC 60050-161:1990, *International Electrotechnical Vocabulary (IEV) – Part 161: Electromagnetic compatibility*. + + + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.80-202211-I_PDF-E/raw.md b/marked/K/T-REC-K.80-202211-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..62a651b1147c83976f22b2c90584f03007c9921b --- /dev/null +++ b/marked/K/T-REC-K.80-202211-I_PDF-E/raw.md @@ -0,0 +1,349 @@ + + +# Recommendation **ITU-T K.80 (11/2022)** + +SERIES K: Protection against interference + +--- + +## **Electromagnetic compatibility requirements for telecommunication network equipment in the frequency range 1 GHz-40 GHz** + +![ITU logo](390120de4fe440c42fea8154fcaad334_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with white lines representing latitude and longitude, and the letters 'ITU' in a bold, blue, sans-serif font overlaid on the globe. + +ITU logo + + + +# Recommendation ITU-T K.80 + +# Electromagnetic compatibility requirements for telecommunication network equipment in the frequency range 1 GHz-40 GHz + +## Summary + +Recommendation ITU-T K.80 presents electromagnetic compatibility (EMC) requirements for all types of telecommunication equipment in the frequency range between 1 GHz and 40 GHz. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.80 | 2009-07-14 | 5 | 11.1002/1000/10017 | +| 2.0 | ITU-T K.80 | 2022-11-29 | 5 | 11.1002/1000/15179 | + +## Keywords + +EMC, performance criteria, protection, radiated emissions, radiated immunity. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2023 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 2 | +| 3.1 Terms defined elsewhere ..... | 2 | +| 3.2 Terms defined in this Recommendation..... | 2 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 2 | +| 6 Radiated emission between 1 GHz and 40 GHz..... | 2 | +| 6.1 Limits..... | 2 | +| 7 Radiated immunity between 1 GHz and 6 GHz ..... | 4 | +| 7.1 Test level ..... | 4 | +| 7.2 General test conditions ..... | 4 | +| 7.3 Specific test conditions..... | 4 | +| 7.4 Performance criteria ..... | 5 | +| 8 Immunity requirements in close proximity use of wireless devices..... | 5 | +| 8.1 Test level ..... | 5 | +| 8.2 General test conditions ..... | 6 | +| 8.3 Specific test conditions..... | 6 | +| 8.4 Performance criteria ..... | 6 | +| Bibliography..... | 7 | + +## **Introduction** + +This Recommendation completes the electromagnetic compatibility requirements for all types of telecommunication equipment contained in [ITU-T K.136] and [ITU-T K.137], specifying requirements for phenomena at frequencies between 1 GHz and 40 GHz. + +Telecommunication equipment can be influenced or can influence the electromagnetic environment at frequencies between 1 GHz and 40 GHz. + +The use of radio devices, including mobile phone International Mobile Telecommunications-2020, wireless local area networks, Internet of things and broadband access radio equipment, in this frequency range highlights the need for analysis. + +The requirements given in specific product family Recommendations take precedence over those given in this Recommendation. + +# Recommendation ITU-T K.80 + +# Electromagnetic compatibility requirements for telecommunication network equipment in the frequency range 1 GHz-40 GHz + +# 1 Scope + +This Recommendation applies to all types of telecommunication equipment and considers electromagnetic radiated emission and immunity phenomena at frequencies between 1 GHz and 40 GHz. This Recommendation describes general electromagnetic compatibility (EMC) requirements above 1 GHz. Specific EMC product Recommendations for telecommunication equipment take precedence over this Recommendation. Therefore, this Recommendation applies when no specific product EMC Recommendations are available. + +EMC phenomena below 1 GHz are covered by product Recommendations such as [ITU-T K.136] and [ITU-T K.137]. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU T K.114] Recommendation ITU-T K.114 (2022), *Electromagnetic compatibility requirements and measurement methods for digital cellular mobile communication base station equipment*. +- [ITU-T K.127] Recommendation ITU-T K.127 (2017), *Immunity requirements for telecommunication equipment in close proximity use of wireless devices*. +- [ITU-T K.136] Recommendation ITU-T K.136 (2022), *Electromagnetic compatibility requirements for radio telecommunication equipment*. +- [ITU-T K.137] Recommendation ITU-T K.137 (2022), *Electromagnetic compatibility requirements and measurement methods for wireline telecommunication network equipment*. +- [ITU-R SM.329] Recommendation ITU-R SM.329-12 (2012), *Unwanted emissions in the spurious domain*. +- [IEC CISPR 16-1-4] International Standard IEC CISPR 16-1-4:2020, *Specification for radio disturbance and immunity measuring apparatus and methods – Part 1-4: Radio disturbance and immunity measuring apparatus – Antennas and test sites for radiated disturbance measurements*. +- [IEC CISPR 16-2-3] International Standard IEC CISPR 16-2-3:2019, *Specification for radio disturbance and immunity measuring apparatus and methods – Part 2-3: Methods of measurement of disturbances and immunity – Radiated disturbance measurements*. +- [IEC 61000-4-3] International Standard IEC 61000-4-3:2020, *Electromagnetic compatibility (EMC) – Part 4-3: Testing and measurement techniques – Radiated, radio-frequency, electromagnetic field immunity test*. + +[IEC 61000-4-39] International Standard IEC 61000-4-39:2017, *Electromagnetic compatibility (EMC) – Part 4-39: Testing and measurement techniques – Radiated fields in close proximity – Immunity test.* + +# 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 electromagnetic emission** [b-IEC 60050-161]: Phenomenon by which electromagnetic energy emanates from a source. + +**3.1.2 immunity (to a disturbance)** [b-IEC 60050-161]: The ability of a device, equipment or system to perform without degradation in the presence of an electromagnetic disturbance. + +### 3.2 Terms defined in this Recommendation + +None. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +EMC Electromagnetic Compatibility + +EUT Equipment Under Test + +FSOATS Free Space Open Area Test Site + +IP Internet Protocol + +# 5 Conventions + +None. + +# 6 Radiated emission between 1 GHz and 40 GHz + +Radiated emissions measurements shall be performed in a free space open area test site (FSOATS) as specified in [IEC CISPR 16-1-4] with the test methods specified in Table 1 and Table 2. + +### 6.1 Limits + +Telecommunication equipment installed inside telecommunication centres shall meet the radiated emission limits listed in Table 1 or Table 3. The emissions shall satisfy both limits when measured with the corresponding CISPR detector. + +Telecommunication equipment installed outside telecommunication centres shall meet the radiated emission limits listed in Table 2 or Table 4. The emissions shall satisfy both limits when measured with the corresponding CISPR detector. + +The limits presented in Tables 1 and 2 are specified at 3 m measurement distance. + +**Table 1 – Radiated emission limits +equipment installed inside a telecommunication centre** + +| Frequency range
(GHz) | Average limit
dB( $\mu$ V/m) | Peak limit
dB( $\mu$ V/m) | +|--------------------------|---------------------------------|------------------------------| +| 1 to 6 (Note 2) | 60 | 80 | +| 6 to 40 (Note 2) | 60 | – | + +NOTE 1 – The lower limit applies at the transition frequency. +NOTE 2 – The limits are given for 3 m measurement distance in FSOATS. [IEC CISPR 16-1-4] and [IEC CISPR 16-2-3] specify the test instrumentation and the test method, respectively, up to 18 GHz. [b-IEEE/ANSI C63.4] specifies test instrumentation and a test method in the frequency range from 18 GHz to 40 GHz. + +**Table 2 – Radiated emission limits +equipment installed outside a telecommunication centre** + +| Frequency range
(GHz) | Average limit
dB( $\mu$ V/m) | Peak limit
dB( $\mu$ V/m) | +|--------------------------|---------------------------------|------------------------------| +| 1 to 6 (Note 2) | 54 | 74 | +| 6 to 40 (Note 2) | 54 | – | + +NOTE 1 – The lower limit applies at the transition frequency. +NOTE 2 – The limits are given for 3 m measurement distance in FSOATS. [IEC CISPR 16-1-4] and [IEC CISPR 16-2-3] specify the test instrumentation and the test method, respectively, up to 18 GHz. [b-IEEE/ANSI C63.4] specifies test instrumentation and a test method in the frequency range from 18 GHz to 40 GHz. + +### 6.2 Emission frequency range + +The equipment under test (EUT) shall meet these limits within a frequency range that is determined by the highest frequency present on the equipment as specified in Table 3. + +**Table 3 – Required highest frequency for radiated emission test** + +| Highest internal frequency ( $F_x$ ) | Measured up to highest frequency | +|--------------------------------------|------------------------------------------| +| $F_x \leq 108$ MHz | 1 GHz | +| $108$ MHz $< F_x \leq 500$ MHz | 2 GHz | +| $500$ MHz $< F_x \leq 1$ GHz | 5 GHz | +| $F_x > 1$ GHz | $5 \times F_x$ up to a maximum of 40 GHz | + +$F_x$ : highest fundamental frequency generated or used within the EUT or highest frequency at which it operates. + +## 6.3 Emission from radio transmitter equipment + +Radio transmitter equipment that meets the unintentional emissions requirements of [ITU-R SM.329] does not need additional testing. + +The limits reported in [ITU-R SM.329] shall be selected in accordance with the national radio regulatory authority. + +### 6.4 General test conditions + +Prior to testing, telecommunication equipment shall be installed and configured at the test site in a manner that is representative of the normal installation conditions. + +Equipment shall be tested within the rack or cabinet in which it is normally installed. + +General test conditions for telecommunication equipment are specified in clause 8 of [ITU-T K.137], while those for radio telecommunication equipment are specified in clause 7 of [ITU-T K.136]. + +### 6.5 Specific test conditions + +[ITU-T K.137] specifies test conditions for: access equipment (in its Annex D); Internet protocol (IP) router and switching equipment (in its Annex E); transmission network equipment (in its Annex F); cloud computing network equipment (in its Annex G); switching equipment (in its Annex H); and equipment with a power-over-Ethernet port (in its Annex I). + +[ITU-T K.136] and [ITU-T K.114] specifies test conditions for radio equipment such as: mobile access network equipment (including base stations); fixed radio links equipment (including microwave relay); fixed-satellite service equipment; radio navigation-satellite services equipment; short-range devices; mobile broadband access devices; mobile-satellite service equipment; and wireless access point devices. + +# 7 Radiated immunity between 1 GHz and 6 GHz + +Radiated immunity tests between 1 GHz and 6 GHz shall be performed in accordance with [IEC 61000-4-3]. + +### 7.1 Test level + +The test level is listed in Table 4. + +**Table 4 – Immunity test level** + +| Environmental phenomena | Test level | Units | Basic standard | Performance criteria | Frequency Range (MHz) | +|--------------------------------------|------------|-------|-----------------|----------------------|-----------------------| +| Enclosure port | | | | | | +| Radiofrequency electromagnetic field | 10 | V/m | [IEC 61000-4-3] | A | 1 000-6 000 | +| | | | | | | + +## 7.2 General test conditions + +Prior to testing, telecommunication equipment shall be installed and configured at the test site in a manner that is representative of the normal installation conditions. + +Equipment shall be tested within the rack or cabinet in which it is normally installed. + +The test equipment and test environment shall meet the requirements of [IEC 61000-4-3]. + +General test conditions for telecommunication equipment are specified in clause 8 of [ITU-T K.137], while those for radio telecommunication equipment are specified in clause 7 of [ITU-T K.136]. + +## 7.3 Specific test conditions + +[ITU-T K.137] specifies test conditions for different types of telecommunication equipment, these being: access equipment (in its Annex D); IP router and switching equipment (in its Annex E); transmission network equipment (in its Annex F); cloud computing network equipment (in its Annex G); switching equipment (in its Annex H); and equipment with a power-over-Ethernet port (in its Annex I). + +[ITU-T K.136] and [ITU-T K.114] specify test conditions for different types of telecommunication equipment, these being: mobile access network equipment (including base stations); fixed radio links + +equipment (including microwave relay); fixed-satellite service equipment; radio navigation-satellite services equipment; short-range devices; mobile broadband access devices; mobile-satellite service equipment; and wireless access point devices. + +## 7.4 Performance criteria + +The general performance criteria specified in clause 9 of [ITU-T K.137] for telecommunication network equipment or clause 8 of [ITU-T K.136] for radio equipment shall be applied. + +# 8 Immunity requirements in close proximity use of wireless devices + +When wireless devices are close to telecommunication equipment, an intense electric field will locally permeate the equipment. Radiated immunity tests between 1 GHz and 6 GHz in close proximity shall be performed in accordance with [ITU-T K.127] for the test level and signal and [IEC 61000-4-39] for the test steps, test instrumentation and test method. + +## 8.1 Test level + +The test level is given in Table 5. This test level is the amplitude of the unmodulated carrier signal for level calibration, see clause 6.1 of [ITU-T K.127]. + +Tests shall be performed with the waveform listed in Table 6 and they shall be applied to the EUT individually. + +**Table 5 – Test level** + +| Test level | Unit | Performance criterion | Basic standard | Frequency range (MHz) | Frequency step (MHz) | +|----------------|------|-----------------------|------------------|-------------------------------------------------------------------|----------------------| +| 30
(Note 1) | V/m | A | [IEC 61000-4-39] | 1 805-2 170
(Note 2)
2 400-2 485
5 150-5 875
(Note 3) | 1 MHz | + +NOTE 1 – The test level may be changed only if there are specific reasons requiring a different test level and there is agreement on this between telecommunication operators and manufacturers. + +NOTE 2 – The frequency range 1 805 MHz-2 170 MHz for the immunity test in close proximity applies only for applications outside telecommunication centres. + +NOTE 3 – The frequency range may be changed for deployment in some countries where the frequency bands used are not the same as those specified in this table. + +**Table 6 – Test waveforms (see clause 6.1 of [ITU-T K.127])** + +| Test waveform | Specification | Figure in [ITU-T K.127] of test waveform | +|----------------------|-------------------------------------------------|------------------------------------------| +| Amplitude modulation | Depth: 80%
Rate: 1 kHz sine wave | 1 b) | +| Pulse modulation | Duty cycle: 50%
Modulation frequency: 217 Hz | 1 c) | + +## **8.2 General test conditions** + +Prior to testing, telecommunication equipment shall be installed and configured at the test site in a manner that is representative of the normal installation conditions. + +Equipment shall be tested within any rack or cabinet in which it is normally installed. + +The test equipment and test environment shall meet the requirements of [ITU-T K.127]. + +General test conditions for telecommunication equipment are specified in clause 8 of [ITU-T K.137], while those for radio telecommunication equipment are specified in clause 7 of [ITU-T K.136]. + +## **8.3 Specific test conditions** + +[ITU-T K.137] specifies test conditions for different types of telecommunication equipment, these being: access equipment (in its Annex D); IP router and switching equipment (in its Annex E); transmission network equipment (in its Annex F); cloud computing network equipment (in its Annex G); switching equipment (in its Annex H); and equipment with a power-over-Ethernet port (in its Annex I). + +[ITU-T K.136] and [ITU-T K.114] specify test conditions for different types of telecommunication equipment, these being: mobile access network equipment (including base stations); fixed radio links equipment (including microwave relay); fixed-satellite service equipment; radio navigation-satellite services equipment; short-range devices; mobile broadband access devices; mobile-satellite service equipment; and wireless access point devices. + +## **8.4 Performance criteria** + +The general performance criteria specified in clause 9 of [ITU-T K.137] for telecommunication network equipment or clause 8 of [ITU-T K.136] for radio equipment shall be applied. + +# Bibliography + +- [b-IEC 60050-161] International Standard IEC 60050-161:1990, *International Electrotechnical Vocabulary. Chapter 161: Electromagnetic Compatibility.* +- [b-IEEE/ANSI C63.4] IEEE/ANSI C63.4-2014, *American National Standard for methods of measurement of radio noise emissions from low-voltage electrical and electronic equipment in the range of 9 kHz to 40 GHz.* + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.81-202408-I_PDF-E/raw.md b/marked/K/T-REC-K.81-202408-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..8bc51bd95ba91955a6eacb8e0e6aad30a1290450 --- /dev/null +++ b/marked/K/T-REC-K.81-202408-I_PDF-E/raw.md @@ -0,0 +1,511 @@ + + +# Recommendation **ITU-T K.81 (08/2024)** + +SERIES K: Protection against interference + +--- + +# **High-power electromagnetic immunity guide for telecommunication systems** + +![ITU logo](390120de4fe440c42fea8154fcaad334_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with white lines representing latitude and longitude, and the letters 'ITU' in a bold, blue, sans-serif font superimposed on the globe. + +ITU logo + + + +# Recommendation ITU-T K.81 + +# High-power electromagnetic immunity guide for telecommunication systems + +## Summary + +In an information security management system (ISMS) based on Recommendation ITU-T X.1051 and ISO/IEC Standards 27001 and 27002, physical security is a key issue. The electromagnetic interference caused by a high-power electromagnetic (HPEM) attack and the ability to intercept information due to unintentional electromagnetic emissions of equipment are significantly determined by the applied physical security measures. + +When information security is managed, it is necessary to evaluate and mitigate the threat to either the equipment or the site. This threat is related to "vulnerability" and "confidentiality" in ISMS. + +Recommendation ITU-T K.81 presents guidance on establishing the threat level presented by an intentional HPEM attack and the physical security measures that may be used to minimize this threat. ITU-T K-Supplement 5 provides the calculation results of the intentional HPEM threats. The HPEM sources considered are those presented in IEC 61000-2-13, as well as some additional sources that have emerged more recently. + +Recommendation ITU-T K.81 also provides information on the vulnerability of equipment. The example of vulnerability is provided in ITU-T K-Supplement 5. The equipment is assumed to meet the immunity requirements presented in Recommendation ITU-T K.48 and relevant resistibility requirements, such as those described in Recommendations ITU-T K.20, ITU-T K.21 and ITU-T K.45. + +The 2016 version of this Recommendation deleted Appendices I, II and III. Appendix I was republished as Supplement 5 to the K-series Recommendations, and the relevant parts of Appendix II were transferred to ITU-T K.115. + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T K.81 | 2009-11-29 | 5 | 11.1002/1000/10018 | +| 2.0 | ITU-T K.81 | 2014-08-29 | 5 | 11.1002/1000/12287 | +| 3.0 | ITU-T K.81 | 2016-06-29 | 5 | 11.1002/1000/12877 | +| 4.0 | ITU-T K.81 | 2024-08-13 | 5 | 11.1002/1000/16005 | + +## Keywords + +Electromagnetic security, high-power electromagnetic, HPEM, IEMI, immunity, resistibility, electrostatic discharge. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, and information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2024 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|--------------------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 2 | +| 3.1 Terms defined elsewhere ..... | 2 | +| 3.2 Terms defined in this Recommendation..... | 2 | +| 4 Abbreviations and acronyms ..... | 3 | +| 5 Conventions ..... | 4 | +| 6 Threat evaluation ..... | 4 | +| 6.1 Definitions of threat portability levels..... | 4 | +| 6.2 Definition of the intrusion area..... | 4 | +| 6.3 Definition of threat availability levels..... | 6 | +| 6.4 Examples of threat devices..... | 6 | +| 7 Vulnerability of devices to be protected..... | 7 | +| 7.1 Definition of vulnerability classifications ..... | 7 | +| 7.2 Examples of vulnerability of various equipment types to be protected ..... | 8 | +| 8 Determination of threat mitigation levels regarding electromagnetic phenomena..... | 9 | +| 8.1 General ..... | 10 | +| Bibliography..... | 12 | + + + +# Recommendation ITU-T K.81 + +## High-power electromagnetic immunity guide for telecommunication systems + +# 1 Scope + +This Recommendation presents guidance on: + +- establishing the threat level presented by an intentional high-power electromagnetic (HPEM) attack on an electronic device or system; +- the physical security measures that may be employed to reduce this threat level; +- establishing the vulnerability of the equipment (or system) to be protected from a HPEM attack. + +When establishing detailed countermeasures to HPEM attacks, it is extremely important that the threat level (strength) of the attack be adequately estimated. Underestimation means that the applied countermeasures will be insufficient and hence increases the risk that equipment may malfunction; whereas overestimation means that the applied countermeasures may add significant (and unnecessary) cost to the equipment or system. + +Estimation of the threat level (strength) is calculated using sources such as the IEC Standards, as well as the independent market studies performed during the preparation of this Recommendation. + +The vulnerability of the electronic device (or system) to be protected is based on either an assessment of the standards that the electronic device (or system) satisfy, or the results of independent evaluation (i.e., testing) of a sample device. + +The threat and vulnerability levels considered within this Recommendation reflect the technology levels current as of 2016. Hence, it is expected that this Recommendation will require periodic review in the light of ongoing technological change in order to remain current. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.20] Recommendation ITU-T K.20 (2015), *Resistibility of telecommunication equipment installed in a telecommunications centre to overvoltages and overcurrents*. +- [ITU-T K.21] Recommendation ITU-T K.21 (2015), *Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents*. +- [ITU-T K.42] Recommendation ITU-T K.42 (1998), *Preparation of emission and immunity requirements for telecommunication equipment – General principles*. +- [ITU-T K.43] Recommendation ITU-T K.43 (2009), *Immunity requirements for telecommunication network equipment*. +- [ITU-T K.44] Recommendation ITU-T K.44 (2012), *Resistibility tests for telecommunication equipment exposed to overvoltages and overcurrents – Basic Recommendation*. + +- [ITU-T K.45] Recommendation ITU-T K.45 (2015), *Resistibility of telecommunication equipment installed in the access and trunk networks to overvoltages and overcurrents*. +- [ITU-T K.48] Recommendation ITU-T K.48 (2006), *EMC requirements for telecommunication equipment – Product family Recommendation*. +- [ITU-T K.66] Recommendation ITU-T K.66 (2011), *Protection of customer premises from overvoltages*. +- [IEC 61000-2-13] IEC 61000-2-13 (2005), *Electromagnetic compatibility (EMC) – Part 2-13: Environment – High-power electromagnetic (HPEM) environments – Radiated and conducted*. +- [IEC CISPR 24] CISPR 24 (2010), *Information technology equipment – Immunity characteristics – Limits and methods of measurement*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 availability** [b-ISO/IEC 27002]: Ensuring that authorized users have access to information and associated assets when required. + +**3.1.2 confidentiality** [b-ITU-T X.800] The property that information is not made available or disclosed to unauthorized individuals, entities, or processes. + +NOTE – In this Recommendation, EMSEC deals with the risk of losing this confidentiality. If this risk cannot be mitigated at the equipment itself, the level of confidentiality is indicated based on the emission values of existing electromagnetic compatibility (EMC) requirements. Appendix II of Recommendation ITU-T K.84 provides further details. + +**3.1.3 emanation** [b-IETF RFC 2828]: A signal (electromagnetic, acoustic, or other medium) that is emitted by a system (through radiation or conductance) as a consequence (i.e., by-product) of its operation, and that may contain information. (See: TEMPEST.) + +**3.1.4 integrity** [b-ISO/IEC 27002]: Safeguarding the accuracy and completeness of information and processing methods. + +**3.1.5 tempest** [b-IETF RFC 2828]: A nickname for specifications and standards for limiting the strength of electromagnetic emanations from electrical and electronic equipment and thus reducing vulnerability to eavesdropping. + +**3.1.6 threat** [b-ISO/IEC 27000]: Potential cause of an unwanted incident, which may result in harm to a system or organization. + +**3.1.7 vulnerability** [b-ITU-T X.1605] Weakness in an information system, system security procedures, internal controls, or implementation that could be exploited by a threat source. + +NOTE – In this Recommendation the term is used when equipment is exposed to HEMP or HPEM. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 threat mitigation:** The preparations made to avoid threat. + +NOTE – In this Recommendation, the threat caused by a malfunction due to a vulnerability to high-altitude electromagnetic pulses (HEMP) or high-power electromagnetic (HPEM) emissions, or a lack of confidentiality due to an insufficient electromagnetic emanations security (EMSEC) are treated. The level of the threat mitigation of the equipment can be calculated from the threat level and the vulnerability level. + +**3.2.2 electromagnetic emanations security (EMSEC):** Physical measures to keep confidentiality by preventing the propagation of signals that emanate from a system, particularly by blocking electromagnetic radiation. + +NOTE – In this Recommendation, EMSEC means only information leakage due to unintentional electromagnetic emission. + +## **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|----------------------------------------| +| AM | Amplitude Modulation | +| ASP | Application Service Provider | +| CB | Citizen Band | +| CSP | Contents Service Provider | +| CW | Continuous Wave | +| DB | Database | +| DC | Direct Current | +| EM | Electromagnetic | +| EMC | Electromagnetic Compatibility | +| EMSEC | EM emanations Security | +| ERP | Enterprise Resource Planning | +| FET | Field Effect Transistor | +| FM | Frequency Modulation | +| FTP | File Transfer Protocol | +| GTEM | Gigahertz Transverse Electromagnetic | +| HEMP | High-altitude EM Pulse | +| HF | High Frequency | +| HPEM | High Power EM | +| IGBT | Insulated Gate Bipolar Transistor | +| IP | Internet Protocol | +| IRA | Impulse Radiating Antenna | +| ISMS | Information Security Management System | +| ISP | Internet Service Provider | +| IT | Information Technology | +| LAN | Local Area Network | +| MSP | Management Service Provider | +| NEBS | Network Equipment Building Systems | +| PC | Personal Computer | +| SE | Shield Effect | +| TCP | Transfer Control Protocol | + +## 5 Conventions + +None. + +## 6 Threat evaluation + +To evaluate a threat, it is necessary to consider its: + +- portability level; +- intrusion areas, and +- availability level. + +## 6.1 Definitions of threat portability levels + +This Recommendation defines the four levels of threat portability presented in Table 1. + +**Table 1 – Definitions of threat portability levels** + +| Threat portability level | Definition | +|--------------------------|--------------------------------------| +| PI | Pocket-sized or body-worn (Note 1) | +| PII | Briefcase or backpack sized (Note 2) | +| PIII | Motor-vehicle sized (Note 3) | +| PIV | Trailer-sized (Note 4) | + +NOTE 1 – This portability level applies to threat devices that can be hidden in the human body and/or in clothing. + +NOTE 2 – This portability level applies to threat devices that are too large to be hidden in the human body and/or in clothing, but that are still small enough to be carried by a person (such as in a briefcase or a back-pack). + +NOTE 3 – This portability level applies to threat devices that are too large to be easily carried by a person, but small enough to be hidden in a typical consumer motor vehicle. + +NOTE 4 – This portability level applies to threat devices that are too large to be either easily carried by a person or hidden in a typical consumer motor vehicle. Such threat devices require transportation using a commercial/industrial transportation vehicle. + +## 6.2 Definition of the intrusion area + +This Recommendation recognizes the concept of intrusion area. This concept indicates both: + +- the portability levels of threat device(s) that may be present; +- the typical minimum separation distance that may be achieved between the threat device and the electronic equipment to be protected. + +The concept of intrusion area is depicted in Figure 1 and summarized in Table 2. + +Intrusion area Zone 0 applies to the public spaces surrounding the site or building that houses the equipment to be protected. Within this area, people and vehicles are free to move in accordance with local legal requirements (i.e., the owner of the equipment to be protected has no ability to control the movement of people and/or vehicles). Hence, Zone 0 can contain threat devices of all the portability levels defined in Table 1. The typical minimum separation between the threat devices located in this zone and the equipment to be protected is between ~100 m and ~10 m. The higher figure is associated with situations in which the equipment to be protected is situated inside a building that is surrounded by a site where access is controlled. The lower figure is associated with situations in which the equipment to be protected is situated inside a building that is surrounded by a public space. This + +applies to buildings located in urban centres, where the building may be surrounded by publicly accessible streets. + +Intrusion area Zone 1 applies to locations within the same site that houses the equipment to be protected. It is recommended that physical security be applied at the site entrance, such that vehicular access to the site is controlled. Hence it is presumed that Zone 1 will not contain threat devices of portability levels PIII and PIV, i.e., that anything trailer-sized will not be admitted and smaller vehicles will be left at a visitor car park. It is recommended that the location of the visitor car park be considered as part of the site physical security plan. A visitor car park located outside the site perimeter, near to the entrance will maximize the separation of any threat of portability levels PIII and PIV and the equipment to be protected. If the visitor car park is to be located within the site boundary, it should be situated as far as possible from the equipment to be protected. The typical separation between the threat devices located in this zone and the equipment to be protected is between 10 m and 100 m. + +Intrusion area Zone 2 applies to locations within the same building that house the equipment to be protected. It is recommended that physical security be applied at the site entrance, such that vehicular access to the site is controlled. This means that Zone 2 will not contain threat devices of portability levels PIII and PIV, i.e., that anything trailer-sized will not be admitted and smaller vehicles will be left at a visitor car park. It is further recommended that physical security be applied to prevent access to the room containing the equipment under protection. Hence, the typical minimum separation between the threat devices located in this zone and the equipment to be protected is between 1 m and 10 m. + +Intrusion area Zone 3 applies to locations within the same room that houses the equipment to be protected (i.e., the equipment room). It is recommended that physical security be applied at the site entrance, such that vehicular access to the site is controlled. This means that Zone 3 will not contain threat devices of portability levels PIII and PIV, i.e., that anything trailer-sized will not be admitted and smaller vehicles will be left at a visitor car park. It is further recommended that physical security be applied to control access to the room containing the equipment to be protected. This physical security means that all types of briefcases and backpacks should be surrendered to a security guard before access to the room is granted. Additional physical security measures are also recommended: visitors to the equipment room shall be asked to empty the content of their pockets and/or undergo some additional screening (such as via a metal detector) before access is granted. Hence, the typical minimum separation between the threat devices located in this zone and the equipment to be protected is between 0 m and 1 m. + +Hence, it is necessary for the owner of the equipment to be protected to review the intended (or actual) location of the equipment and develop a physical security protocol that controls the ability of threat devices to be taken near to the equipment to be protected. + +![Diagram illustrating the classification of intrusion areas into four zones based on distance from a threat device. Zone 0 is outside the site (>100 m), Zone 1 is within the site (10-100 m), Zone 2 is within the building (1-10 m), and Zone 3 is within the same room (<1 m). The diagram shows radiated and conducted signals propagating from a threat device through walls and across distances.](d4af765160d04ecef538e5066006dc77_img.jpg) + +K.81(14)\_F01 + +Diagram illustrating the classification of intrusion areas into four zones based on distance from a threat device. Zone 0 is outside the site (>100 m), Zone 1 is within the site (10-100 m), Zone 2 is within the building (1-10 m), and Zone 3 is within the same room (<1 m). The diagram shows radiated and conducted signals propagating from a threat device through walls and across distances. + +**Figure 1 – Classification of intrusion areas** + +**Table 2 – Intrusion area and portability levels** + +| Intrusion area | Threat device location | Threat device portability levels (Note) | Typical minimum separation distance (m) | +|----------------|------------------------|-----------------------------------------|-----------------------------------------| +| Zone 0 | Public space | PI, PII, PIII, PIV | > 100 | +| Zone 1 | Same site | PI, PII | 100 – 10 | +| Zone 2 | Same building | PI, PII | 10 – 1 | +| Zone 3 | Same room | PI, PII | < 1 | + +NOTE – The portability level of the threat devices that may be located in each intrusion zone is determined by the physical security measures applied. + +## 6.3 Definition of threat availability levels + +This Recommendation recognizes the four threat availability levels (AI to AIV) presented in Table 3. The threat availability level shall be thought of as a measure of both the cost and the technological sophistication of the threat device: + +**Table 3 – Definitions of threat availability levels** + +| Availability level | Definition | Examples | +|--------------------|----------------|-------------------------------------------------------------------------------------| +| AI | 'Consumer' | Wireless local area network (LAN) device, stun-gun, illegal citizen band (CB) radio | +| AII | 'Hobbyist' | CW generator, amateur wireless device | +| AIII | 'Professional' | Navigation radar | +| AIV | 'Bespoke' | Impulse radiating antenna (IRA), JOLT [b-JOLT], commercial radar | + +## 6.4 Examples of threat devices + +Examples of threat devices for which the assessment is described in clauses 6.1, 6.2 and 6.3 are summarized in Table 4. The basis of the data presented is given in [b-ITU-T K-Sup.5]. + +**Table 4 – Example of threats related to high-power electromagnetic waves** + +| Threat type | Example of attack device | Intrusion range on attack side | Strength | Frequency range | Portability | Availability | Threat number | +|-----------------------------------------|-----------------------------------|--------------------------------|--------------------------|--------------------------|-------------|--------------|---------------| +| Electromagnetic wave attack – Radiated | JOLT | Zone 0 | 72 kV/m@100 m | 50 MHz-2 GHz | PIV | AIV | K1-0 | +| | IRA (Hi-tech) | Zone 0 | 12.8 kV/m@100 m | 300 MHz-10 GHz | PIV | AIV | K1-1 | +| | Commercial radar (Mid-tech) | Zone 0 | 60 kV/m@100 m | 1 GHz-10 GHz (1.285 GHz) | PIV | AIV | K1-2 | +| | Navigation radar | Zone 0 | 385 V/m@100 m | 1 GHz-10 GHz (9.41 GHz) | PIII | AIII | K1-3 | +| | Magnetron generator | Zone 1 | 475 V/m@10 m | 1 GHz-3 GHz | PIII | AII | K1-4 | +| | Amateur wireless device | Zone 2 | 286 V/m@1 m | 100 MHz-3 GHz | PII | AII | K1-5 | +| | Amateur wireless device | Zone 3 | 169 V/m@10 cm | 100 MHz-3 GHz | PI | AI | K1-6 | +| | Illegal CB radio | Zone2 | 573 V/m@10 m | 27 MHz | PII | AI | K1-7 | +| Electrostatic discharge attack | Stun gun | Zone 3 | 500 kV | 100 MHz-3 GHz | PI | AI | K2-1 | +| Electromagnetic wave attack – Conducted | Lightning-surge generator | Zone 0 | 50 kV (charging voltage) | 1.2/50 μs 10/700 | PIV | AIV | K3-1 | +| | Compact lightning-surge generator | Zones 0-3 | 10 kV (charging voltage) | 1.2/50 μs 10/700 | PII | AII | K3-2 | +| | CW generator | Zones 0-3 | 100 V~240 V/4 kV | 1 Hz-10 MHz | PII | AII | K3-3 | +| | Commercial power supply | Zones 0-3 | 100 V~240 V | 50/60 Hz | PI | AI | K3-4 | + +# 7 Vulnerability of devices to be protected + +## 7.1 Definition of vulnerability classifications + +The immunity standards and the overvoltage standards shown in Table 5 and Table 6 have several differences with regard to the vulnerability levels of devices to be protected. Specific vulnerability levels are set for each of the standards. ZI1 to ZI3 indicates the vulnerability level with respect to immunity standards while ZK1 to ZK5 indicates the vulnerability level with respect to overvoltage standards. The differences are described in [b-ITU-T K-Sup.5]. + +In addition, the typical immunity level for routers servers obtained by testing is described in Table 7. This immunity level is comparable to results given in [ITU-T K.48]. + +**Table 5 – Immunity standards and vulnerability levels** + +| Vulnerability level | Standard | Target device | Remarks | +|---------------------|-------------------|-------------------|------------------------| +| ZI1 | [IEC CISPR 24] | IT equipment | International Standard | +| ZI2 | [ITU-T K.48] | Network equipment | Recommendation | +| ZI1 | [ITU-T K.43] | Network equipment | Recommendation | +| ZI1 | [b-NTT-TR 549001] | Network equipment | NTT | +| ZI1 | [b-NEBS GR-1089] | Network equipment | US Standard | +| ZI3 | NEBS LEVEL 3 | Network equipment | US Standard | + +**Table 6 – Overvoltage standards and vulnerability levels** + +| Vulnerability level | Standard | Target device | Remarks | +|---------------------|------------------|-----------------------------------------|----------------| +| ZK1 | [ITU-T K.20] | Network equipment | Recommendation | +| ZK2 | [ITU-T K.21] | Terminal equipment | Recommendation | +| ZK3 | [ITU-T K.66] | Communication device, network equipment | Recommendation | +| ZK4 | [b-NEBS GR-1089] | Network equipment | US Standard | +| ZK5 | NEBS LEVEL 3 | Network equipment | US Standard | + +**Table 7 – Immunity levels of typical IT devices** + +| Type of EM emanation | Immunity level | +|--------------------------------|-----------------------------------------------------------------------------------| +| Radiated electromagnetic field | 3 V/m (actual field value) (Note) | +| Conducted voltage | 3 V (actual voltage value) (Note) | +| Static discharge | 8 kV (direct discharge) | +| Lightning surge | 4 kV (power port – line to ground)
2 kV (communications port – line to ground) | + +NOTE – This immunity level corresponds to a carrier that is subjected to 80% amplitude modulation (AM) with a 1 kHz tone. + +## 7.2 Examples of vulnerability of various equipment types to be protected + +An example of vulnerability of equipment to be protected will be described according to the classification definitions above. Many of the immunity standards were established several years ago and in the case of equipment with long-life expectancy such as telephone equipment, prognosis is difficult. Telephone line immunity and overvoltage vulnerability levels are shown in Table 9. + +For IP equipment, various levels of vulnerability are identified in Table 10 that reflect the service level agreements (SLAs) that are offered commercially. Table 8 provides a description of the types of service provider. For a management service provider (MSP), it is assumed that the equipment is of network equipment building systems (NEBS) Level 3 ('carrier grade'). + +For PCs or the servers that are typically used, a general immunity level of ZI2, as shown in Table 11, is assumed. In the case of electromagnetic security, it is necessary to assume equipment having an immunity level of ZI1. + +Examples of the vulnerability levels of various types of equipment to be protected are shown in Table 9, Table 10 and Table 11. + +**Table 8 – Type of service provider** + +| Service provider | Description | +|------------------------------------|--------------------------------------------------------------------------------------------------------------------------------| +| Application service provider (ASP) | A provider that provides business application software to a customer via a network such as the Internet. | +| Contents service provider (CSP) | A provider that stores and distributes digital contents. | +| Internet service provider (ISP) | A provider that performs a service for connecting to the Internet. | +| Management service provider (MSP) | A provider that takes responsibility for operation, monitoring and maintenance of servers or networks belonging to a business. | + +**Table 9 – Vulnerability level of telephone lines** + +| Type | Immunity | Overvoltage | +|------------------------------------------------|-----------------|--------------------| +| General public line | ZI1 | ZK1 | +| Dedicated line (general) | ZI1 | ZK1 | +| Dedicated line (fire department, police, etc.) | ZI1 | ZK1 | + +**Table 10 – Vulnerability level of IP equipment (network service)** + +| Type | General level (ISP, etc.) | | Carrier grade (MSP, etc.) | | +|-------------------------------|----------------------------------|--------------------|----------------------------------|--------------------| +| | Immunity | Overvoltage | Immunity | Overvoltage | +| Data centre (E-Commerce site) | ZI1 | ZI1 | ZI3 | ZK5 | +| Data centre (storage) | ZI1 | ZI1 | ZI3 | ZK5 | +| Router, switching | ZI1 | ZI1 | ZI3 | ZK5 | + +**Table 11 – Vulnerability level of IP equipment (company network)** + +| Type | Immunity | Overvoltage | +|-------------------------------------------|-----------------|--------------------| +| PC | ZI2 | ZI1 | +| Mail server | ZI2 | ZI1 | +| Enterprise resource planning (ERP) server | ZI2 | ZI1 | +| Storage | ZI2 | ZI1 | +| Customer database (DB) server | ZI2 | ZI1 | +| Router, switch | ZI2 | ZI1 | + +# **8 Determination of threat mitigation levels regarding electromagnetic phenomena** + +This clause presents general guidance for the determination of equipment threat mitigation levels and presents some examples. + +## 8.1 General + +The threat levels generated by a high-power EM (HPEM) attack (described in clause 5) all exceed the vulnerability levels of protected devices (described in clause 6) and hence a HPEM attack will affect the device or system. + +Given that the purpose of threat mitigation is to reduce the threat to a level equal to or below the vulnerability level of the device (or system), the required EM mitigation level is the margin between the threat level and the equipment's vulnerability level, given by: + +$$(\text{Threat mitigation level}) = (\text{Threat level}) - (\text{Vulnerability level}) \quad (1)$$ + +The shield effect (SE) is calculated in dB by: + +$$SE = 20\log_{10}\{(\text{Threat level})/(\text{Vulnerability level})\} \quad (2)$$ + +Assuming: + +- that the applied physical security protocol can restrict the threat devices to an availability level of no higher than AIII, and +- that the vulnerability level of general IT equipment is ZI2, + +then the threat mitigation level that is required to be achieved via either shielding and/or filtering is as shown in Table 12 and the overvoltage mitigation level is as shown in Table 13. + +**Table 12 – Examples of the calculation of the required threat mitigation level of general IT equipment for a threat of AIII or less** + +| Threat number | Threat strength (V) | Vulnerability (V) | Threat mitigation level (dB) | Frequency/waveform | Counter-measure location | Threat mitigation achieved via | +|---------------|---------------------|-------------------|------------------------------|--------------------|--------------------------|-------------------------------------------------| +| K1-3 | 385 | 3 | 43 | 1 GHz-10 GHz | Zones 0-3 | Shielding | +| K1-4 | 475 | 3 | 44 | 1 GHz-3 GHz | Zones 1-3 | Shielding | +| K1-5 | 286 | 3 | 40 | 100 MHz-3 GHz | Zones 2-3 | Shielding | +| K1-6 | 169 | 3 | 35 | 100 MHz-3 GHz | Zone 3 | Shielding | +| K1-7 | 573 | 3 | 46 | 27 MHz | Zones 2-3 | Shielding | +| K2-1 | $5 \times 10^5$ | $8 \times 10^4$ | 16 | 100 MHz-3 GHz | Zone 3 | Shielding or static electricity countermeasures | +| K3-3 | 240 | 3 | 38 | 1 Hz-10 MHz | Zones 2-3 | Filter | +| K3-4 | 240 | 3 | 38 | 50/60 Hz | Zones 2-3 | Filter | + +**Table 13 – Examples of the calculation of the required threat mitigation level of general IT equipment for a threat of AIII or less (overvoltage)** + +| | Waveform | Restriction voltage | Peak current | Recommended element | Recommended operating voltage | +|--------------------|-------------|---------------------|--------------|---------------------|----------------------------------------------------------------------------------------------------------------------------| +| Communication port | Combination | 500 V | 5 kA | Arrester | 1.6 × or more of the voltage used by the equipment.
270 V or more when the equipment used is a commercial power supply. | +| | 10/700 | | 500 A | | | +| Power-supply port | Combination | 4 kV | 5 kA | Varistor | | +| | 10/700 | | 500 A | | | + +When there is a possibility of an EM emanations security (EMSEC) device coming within 20 m of the equipment to be protected, the threat mitigation level is 15 dB at 30 MHz to 1 GHz. The relationship between the required threat mitigation level and the frequency is as shown in Figure 2. + +![Figure 2: A graph showing Shield effect (dB) on the Y-axis (0 to 80) versus Frequency (MHz) on the X-axis (logarithmic scale from 10 to 10000). The graph displays several step-like curves representing different threat mitigation levels (K1-7, K1-5, K1-4, K1-3, K4-4, K2-1, K1-6) across various zones (Zone 2-3, Zone 3, Zone 1-3, Zone 0-).](af06598cfb31b517e79b50d74f72a0ca_img.jpg) + +The graph illustrates the relationship between Shield effect (dB) and Frequency (MHz) for various threat mitigation levels and zones. The Y-axis represents Shield effect (dB) from 0 to 80. The X-axis represents Frequency (MHz) on a logarithmic scale from 10 to 10000. The curves show the required shield effect for different zones and threat mitigation levels (K1-7, K1-5, K1-4, K1-3, K4-4, K2-1, K1-6) across the frequency range. + +| Threat Mitigation Level | Zone | Shield Effect (dB) | Frequency Range (MHz) | +|-------------------------|----------|--------------------|-----------------------| +| K1-7 | Zone 2-3 | 45 | 10 - 100 | +| K1-5 | Zone 2-3 | 40 | 100 - 1000 | +| K1-4 | Zone 1-3 | 45 | 1000 - 10000 | +| K1-3 | Zone 0- | 40 | 10000 - 100000 | +| K4-4 | Zone 3 | 15 | 10 - 100 | +| K2-1 | Zone 3 | 15 | 100 - 1000 | +| K1-6 | Zone 3 | 35 | 1000 - 10000 | + +Figure 2: A graph showing Shield effect (dB) on the Y-axis (0 to 80) versus Frequency (MHz) on the X-axis (logarithmic scale from 10 to 10000). The graph displays several step-like curves representing different threat mitigation levels (K1-7, K1-5, K1-4, K1-3, K4-4, K2-1, K1-6) across various zones (Zone 2-3, Zone 3, Zone 1-3, Zone 0-). + +**Figure 2 – Example of the calculation of the relationship between the threat mitigation level and frequency** + +## Bibliography + +- [b-ITU-T K-Sup.5] ITU-T K-series Recommendations – *Supplement 5 (2016), ITU-T K.81 – Estimation examples of the high-power electromagnetic threat and vulnerability for telecommunication systems.* +- [b-ITU-T X.800] Recommendation ITU-T X.800 (1991), *Security architecture for Open Systems Interconnection for CCITT applications.* +- [b-ITU-T X.1605] Recommendation ITU-T X.1605, *Security requirements of public Infrastructure as a Service (IaaS) in cloud computing.* +- [b-ISO/IEC 27002] ISO/IEC 27002 (2013), *Information technology – Security techniques – Code of practice for information security management.* +- [b-IETF RFC 2828] IETF RFC 2828 (2000), *Internet Security Glossary.* +- [b-JOLT] Baum, C.E. et al. (2004), *JOLT: A highly directive, very intensive, impulse-like radiator, Proceedings of the IEEE, Vol. 92, No. 7.* +- [b-NEBS GR-1089] NEBS GR-1089 (2011), *Electromagnetic Compatibility and Electrical Safety – Generic Criteria for Network Telecommunications Equipment.* +- [b-NTT TR 549001] NTT TR 549001 (2005), *Technical Requirements for Immunity of Telecommunications Equipment.* + + + +### SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.87-202408-I_PDF-E/raw.md b/marked/K/T-REC-K.87-202408-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..e600269edb5e9d57f28fbced651f89c2bdfc922f --- /dev/null +++ b/marked/K/T-REC-K.87-202408-I_PDF-E/raw.md @@ -0,0 +1,648 @@ + + +# Recommendation **ITU-T K.87 (08/2024)** + +SERIES K: Protection against interference + +--- + +## **Guide for the application of electromagnetic security requirements – Overview** + +![ITU logo](390120de4fe440c42fea8154fcaad334_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with a white grid pattern, overlaid by the letters 'ITU' in a bold, blue, sans-serif font. The globe is stylized with a small satellite dish icon on the right side. + +ITU logo + + + +# Recommendation ITU-T K.87 + +## Guide for the application of electromagnetic security requirements – Overview + +## Summary + +Recommendation ITU-T K.87 provides general guidelines of information security management for telecommunications organizations are presented in Recommendation ITU-T X.1051, which is based on ISO/IEC 27002. In an information security management system (ISMS) based on Recommendation ITU-T X.1051, physical security is one of key issues, as shown for example in the following text presented in Recommendation ITU-T X.1051: + +"a site whose environment is least susceptible to damage from the environment should be selected for communication centres – where a site is chosen that is vulnerable to environmental damage, appropriate measures should be taken against known hazards including: natural disasters [see e)] and temperature extremes;" + +"a site whose environment is least susceptible to damage from strong electromagnetic field shall be selected for communication centres - where a site is chosen that is exposed to strong electromagnetic fields, appropriate measures should be taken to protect telecommunications equipment rooms with electromagnetic shields;" + +When security is managed, the threat to equipment or site should be evaluated and mitigated. The threat is related to "vulnerability" and "confidentiality" in ISMS. + +This Recommendation, ITU-T K.87, outlines electromagnetic security risks of telecommunication equipment and illustrates how to assess and prevent those risks in order to manage ISMS in accordance with Recommendation ITU-T X.1051. Major electromagnetic security risks addressed in this Recommendation are as follows: + +- natural electromagnetic (EM) threats (e.g., lightning); +- unintentional interference (i.e., electromagnetic interference, EMI); +- intentional interference (i.e., intentional electromagnetic interference, IEMI); +- deliberate EM attacks via high-altitude electromagnetic pulse (HEMP); +- deliberate high-power electromagnetic (HPEM) attacks; +- information leakage from EM emanation (i.e., electromagnetic security, EMSEC). + +Mitigation methods against electromagnetic security threats are also described in this Recommendation. + +## History\* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T K.87 | 2011-11-13 | 5 | 11.1002/1000/11426 | +| 2.0 | ITU-T K.87 | 2016-06-29 | 5 | 11.1002/1000/12878 | +| 3.0 | ITU-T K.87 | 2022-08-13 | 5 | 11.1002/1000/15038 | +| 4.0 | ITU-T K.87 | 2024-08-13 | 5 | 11.1002/1000/16007 | + +## Keywords + +Electromagnetic, Security management, security risks, telecommunication equipment, telecommunication organization. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, and information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2024 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-------------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 3 | +| 3.1 Terms defined elsewhere ..... | 3 | +| 3.2 Terms defined in this Recommendation..... | 4 | +| 4 Abbreviations and acronyms ..... | 5 | +| 5 Conventions ..... | 5 | +| 6 Threats and protection measures relating to electromagnetic phenomena ..... | 5 | +| 6.1 Kinds of threats and relating Recommendations..... | 5 | +| 6.2 Lightning ..... | 6 | +| 6.3 Intentional electromagnetic interference ..... | 7 | +| 6.4 High-altitude electromagnetic pulse (HEMP) ..... | 8 | +| 6.5 High-power electromagnetic (HPEM) ..... | 10 | +| 6.6 Information leakage..... | 12 | +| Bibliography..... | 15 | + + + +# Recommendation ITU-T K.87 + +## Guide for the application of electromagnetic security requirements – Overview + +# 1 Scope + +This Recommendation presents guidance on the management of physical security caused by electromagnetic interference and/or emanation, for telecommunications centre managers to implement the information security management system (ISMS) requirements of [ITU-T X.1051]. + +This Recommendation is a guide for the application of [ITU-T K.78] (high-altitude electromagnetic pulse (HEMP)), [ITU-T K.81] (high-power electromagnetic (HPEM)), [ITU-T K.84] (information leakage) [ITU-T K.115] (mitigation method) and K series Recommendations on lightning protection. + +This Recommendation represents an overview of electromagnetic security; it classifies the environments where devices and equipment in need of protection are installed and classifies predicted threats and vulnerabilities as well as countermeasures. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.20] Recommendation ITU-T K.20 (2022), *Resistibility of telecommunication equipment installed in a telecommunication centre to overvoltages and overcurrents*. +- [ITU-T K.21] Recommendation ITU-T K.21 (2022), *Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents*. +- [ITU-T K.40] Recommendation ITU-T K.40 (2019), *Protection against lightning electromagnetic impulses in telecommunication centres*. +- [ITU-T K.43] Recommendation ITU-T K.43 (2009), *Immunity requirements for telecommunication network equipment*. +- [ITU-T K.44] Recommendation ITU-T K.44 (2019), *Resistibility tests for telecommunication equipment exposed to overvoltages and overcurrents – Basic Recommendation*. +- [ITU-T K.45] Recommendation ITU-T K.45 (2022), *Resistibility of telecommunication equipment installed in the access and trunk networks to overvoltages and overcurrents*. +- [ITU-T K.48] Recommendation ITU-T K.48 (2006), *EMC requirements for telecommunication equipment – Product family Recommendation*. +- [ITU-T K.78] Recommendation ITU-T K.78 (2020), *High altitude electromagnetic pulse immunity guide for telecommunication centres*. +- [ITU-T K.81] Recommendation ITU-T K.81 (2024), *High-power electromagnetic immunity guide for telecommunication systems*. + +- [ITU-T K.84] Recommendation ITU-T K.84 (2011), *Test methods and guide against information leaks through unintentional electromagnetic emissions.* +- [ITU-T K.115] Recommendation ITU-T K.115 (2015), *Mitigation methods against electromagnetic security threats.* +- [ITU-T X.1051] Recommendation ITU-T X.1051 (2023) *Information security, cybersecurity and privacy protection - Information security controls based on ISO/IEC 27002 for telecommunications organizations.* +- [CISPR 32] IEC CISPR 32:2015/AMD1:2019, *Electromagnetic compatibility of multimedia equipment – Emission requirements.* +- [IEC TR 61000-1-5] IEC 61000-1-5: 2004, *Electromagnetic compatibility (EMC) – Part 1-5: General – High power electromagnetic (HPEM) effects on civil systems.* +- [IEC 61000-2-9] IEC 61000-2-9:1996, *Electromagnetic compatibility (EMC) – Part 2: Environment – Section 9: Description of HEMP environment – Radiated disturbance. Basic EMC publication.* +- [IEC 61000-2-10] IEC 61000-2-10:2021, *Electromagnetic Compatibility (EMC) – Part 2-10: Description of HEMP environment – Conducted disturbance.* +- [IEC 61000-2-11] IEC 61000-2-11:1999, *Electromagnetic Compatibility (EMC) – Part 2-11: Environment – Classification of HEMP environments.* +- [IEC 61000-2-13] IEC 61000-2-13:2005, *Electromagnetic compatibility (EMC) – Part 2-13: Environment – High-power electromagnetic (HPEM) environments – Radiated and conducted.* +- [IEC 61000-4-20] IEC 61000-4-20:2022, *Electromagnetic compatibility (EMC) – Part 4-20: Testing and measurement techniques – Emission and immunity testing in transverse electromagnetic (TEM) waveguides.* +- [IEC 61000-4-23] IEC 61000-4-23:2016, *Electromagnetic Compatibility (EMC) – Part 4-23: Testing and measurement techniques – Test methods for protective devices for HEMP and other radiated disturbances.* +- [IEC 61000-4-24] IEC 61000-4-24:2015+AMD1:2023, *Electromagnetic Compatibility (EMC) – Part 4-24: Testing and measurement techniques – Test methods for protective devices for HEMP conducted disturbance.* +- [IEC 61000-4-25] IEC 61000-4-25:2001+AMD1:2012+AMD2:2019, *Electromagnetic compatibility (EMC) – Part 4-25: Testing and measurement techniques – HEMP immunity test methods for equipment and systems.* +- [IEC 61000-4-32] IEC TR 61000-4-32:2002, *Electromagnetic Compatibility (EMC) – Part 4-32: Testing and measurement techniques – High-altitude electromagnetic pulse (HEMP) simulator compendium.* +- [IEC 61000-4-33] IEC 61000-4-33:2005, *Electromagnetic compatibility (EMC) – Part 4-33: Testing and measurement techniques – Measurement methods for high power transient parameters.* +- [IEC 61000-4-36] IEC 61000-4-36:2020, *Electromagnetic compatibility (EMC) – Part 4-36: Testing and measurement techniques – IEMI immunity test methods for equipment and systems.* +- [IEC 61000-5-3] IEC TR 61000-5-3:1999, *Electromagnetic compatibility (EMC) – Part 5-3: Installation and mitigation guidelines – HEMP protection concepts.* + +- [IEC 61000-5-4] IEC TS 61000-5-4:1996, *Electromagnetic compatibility (EMC) – Part 5: Installation and mitigation guidelines – Section 4: Immunity to HEMP – Specifications for protective devices against HEMP radiated disturbance – Basic EMC publication.* +- [IEC 61000-5-5] IEC 61000-5-5:1996, *Electromagnetic compatibility (EMC) – Part 5: Installation and mitigation guidelines – Section 5: Specification of protective devices for HEMP conducted disturbance – Basic EMC publication.* +- [IEC 61000-5-7] IEC 61000-5-7:2001, *Electromagnetic compatibility (EMC) – Part 5-7: Installation and mitigation guidelines – Degrees of protection provided by enclosures against electromagnetic disturbances (EM code).* +- [IEC 61000-5-9] IEC 61000-5-9:2009, *Electromagnetic compatibility (EMC) – Part 5-9: Installation and mitigation guidelines – System-level susceptibility assessments for HEMP and HPEM.* +- [IEC 61000-6-6] IEC 61000-6-6:2003, *Electromagnetic compatibility (EMC) – Part 6-6: Generic standards – HEMP immunity for indoor equipment.* +- [IEC TR 61000-4-35] IEC TR 61000-4-35:2009, *Electromagnetic compatibility (EMC) – Part 4-35: Testing and measurement techniques – HPEM simulator compendium.* + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 availability** [ISO/IEC 27001] [ISO/IEC 27002]: Ensuring that authorized users have access to information and associated assets when required. + +**3.1.2 cable port** [IEC 61000-6-6]: A port at which a conductor or cable is connected to the apparatus. + +**3.1.3 confidentiality** [b-ITU-T X.800] The property that information is not made available or disclosed to unauthorized individuals, entities, or processes. + +NOTE – In Recommendation ITU-T K.87, electromagnetic emanation security (EMSEC) deals with the risk of losing this confidentiality. If this risk cannot be mitigated at the equipment itself, the level of confidentiality is indicated based on the emission values of existing electromagnetic compatibility (EMC) requirements. Appendix II of [ITU-T K.84] provides further details. + +**3.1.4 emanation** [b-IETF RFC 2828]: A signal (electromagnetic, acoustic, or other medium) that is emitted by a system (through radiation or conductance) as a consequence (i.e., by product) of its operation, and that may contain information. (See TEMPEST in [b-IETF RFC 2828]) + +**3.1.5 HEMP immunity test** [IEC 61000-4-25]: The HEMP immunity test is made up of four types of tests. The radiated test is defined in clause 5 of [IEC 61000-4-25], and is used with a large HEMP simulator and a small radiated test facility. The other three types are the conducted tests along the HEMP waveforms; early-, intermediate- and late-HEMP. These are also defined in clause 5 of [IEC 61000 4-25]. + +**3.1.6 high-altitude electromagnetic pulse (HEMP)** [b-IEC glossary], [b-IEC 61000-1-3]: Electromagnetic pulse produced by a nuclear explosion outside the earth's atmosphere. + +Note to entry – Typically above an altitude of 30 km. + +**3.1.7 high-power electromagnetic (HPEM)** [b-IEC glossary], [IEC 61000-4-35]: General area or technology involved in producing intense electromagnetic radiated fields or conducted voltages and currents with a peak power which has the capability to damage or upset electronic systems. + +**3.1.8 high voltage (HV) transmission line** [IEC 61000-4-25]: Power line with a nominal a.c. system voltage equal to or greater than 100 kV. + +**3.1.9 immunity (to a disturbance)** [b-IEC 60050-161]: The ability of a device, equipment or system to perform without degradation in the presence of an electromagnetic disturbance. + +**3.1.10 integrity** [b-ISO/IEC 27001] [ISO/IEC 27002]: Safeguarding the accuracy and completeness of information and processing methods. + +**3.1.11 intentional electromagnetic interference (IEMI)** [b-IEC glossary]: Intentional malicious generation of electromagnetic energy introducing noise or signals into electric and electronic systems, thus disrupting, confusing or damaging these systems for terrorist or criminal purpose. + +**3.1.12 large HEMP simulator** [IEC 61000-6-6] [IEC 61000-4-25]: Transient electromagnetic pulse test facility with a test volume sufficiently large to test objects with cubical dimensions equal to or greater than $1\text{ m} \times 1\text{ m} \times 1\text{ m}$ . + +**3.1.13 power port** [IEC 61000-6-6]: Point at which a conductor or cable carrying the electrical power needed for operation of the equipment is connected to the apparatus. + +**3.1.14 signal port** [IEC 61000-6-6]: A cable port at which there is a cable carrying information for transferring data to or from the apparatus. Examples are input/output (I/O) data ports and telecom ports, etc. + +**3.1.15 small radiated test facility** [IEC 61000-6-6] [IEC 61000-4-25]: Laboratory transient electromagnetic pulse test facility such as a transverse electromagnetic (TEM) cell with a test volume sufficiently large to test objects with cubical dimensions of less than $1\text{ m} \times 1\text{ m} \times 1\text{ m}$ . + +**3.1.16 TEMPEST** [b-IETF RFC 2828]: A nickname for specifications and standards for limiting the strength of electromagnetic emanations from electrical and electronic equipment and thus reducing vulnerability to eavesdropping. + +**3.1.17 threat** [b-ISO/IEC 27000]: Potential cause of an unwanted incident, which may result in harm to a system or organization. + +**3.1.18 vulnerability** [b-NIST-SP-800-30] Weakness in an information system, system security procedures, internal controls, or implementation that could be exploited by a threat source. + +NOTE – In this Recommendation the term is used when equipment is exposed to HEMP or HPEM + +## **3.2 Terms defined in this Recommendation** + +This Recommendation defines the following terms: + +**3.2.1 electromagnetic emanations security (EMSEC)**: Physical measures to keep confidentiality by prevention of signals emanated from a system, particularly by blocking electromagnetic radiation. + +NOTE – In this Recommendation, the term EMSEC is used only for information leakage due to unintentional electromagnetic emission. + +**3.2.2 threat mitigation**: The preparations made to avoid threat. + +NOTE – In this Recommendation, the threat caused by either a malfunction due to a vulnerability to high-altitude electromagnetic pulses (HEMPs) or high-power electromagnetic (HPEM) emissions, or the lack of confidentiality due to insufficient emanation security (EMSEC) are treated. The level of the threat mitigation of the equipment can be calculated from the threat level and the vulnerability level. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|------------------------------------------| +| CB | Citizen Band | +| CW | Continuous Wave | +| EM | Electromagnetic | +| EMC | Electromagnetic Compatibility | +| EMI | Electromagnetic Interference | +| EMSEC | Electromagnetic emanation Security | +| HEMP | High-altitude Electromagnetic Pulse | +| HOB | Height of Burst | +| HPEM | High-Power Electromagnetic | +| HV | High Voltage | +| I/O | Input/Output | +| IEMI | Intentional Electromagnetic Interference | +| IRA | Impulse Radiating Antenna | +| ISMS | Information Security Management System | +| LEMP | Lightning Electromagnetic Pulse | +| PC | Personal Computer | +| TEM | Transverse Electromagnetic | + +# 5 Conventions + +This Recommendation uses the following conventions: + +| | | +|----|----------------------------------------------------------------------| +| E1 | Early time high-altitude electromagnetic pulse electric field | +| E2 | Intermediate time high-altitude electromagnetic pulse electric field | +| E3 | Late time high-altitude electromagnetic pulse electric field | + +# 6 Threats and protection measures relating to electromagnetic phenomena + +## 6.1 Kinds of threats and relating Recommendations + +There are two primary categories on threat relating to the electromagnetic security. + +One is high-power electromagnetic interference, either natural (such as lightning) or deliberate (malicious electromagnetic (EM) attack) that causes damage and disruption for telecommunication centre equipment such as switching, transmission, radio and power. + +Another is information leakage caused by unintentional electromagnetic emanations from telecommunication equipment such as servers, computers and transmission equipment, which process or carry information. There is the possibility that a malicious and skilled eavesdropper could reconstruct significant information from intercepted emanations. + +Table 1 shows some EM security problems, categorized by EM phenomena, discussed in this Recommendation. Also shown are the relevant Recommendations for each security problem and their mitigation techniques. + +The relationship between [ITU-T X.1051] and this Recommendation is shown as Figure 1. + +![Figure 1: A hierarchical diagram showing the relationship between ITU-T X.1051 and ITU-T K.87. ITU-T X.1051 is at the top, connected by a vertical line to ITU-T K.87. ITU-T K.87 is connected by a horizontal line to a vertical line that branches out to five items: ITU-T K.78 (High altitude electromagnetic pulse immunity), ITU-T K.81 (High-power electromagnetic immunity), ITU-T K.84 (Information leaks through electromagnetic emissions), ITU-T K.43, ITU-T K.48, etc. (Immunity and emission), and ITU-T K.20, ITU-T K.21, ITU-T K.44, ITU-T K.45, etc. (Lightning protection). A separate horizontal line from the main vertical line of ITU-T K.87 points to ITU-T K.115 (Mitigation methods against electromagnetic security threats).](007b053fe94a8348f75128a584503fd0_img.jpg) + +Figure 1: A hierarchical diagram showing the relationship between ITU-T X.1051 and ITU-T K.87. ITU-T X.1051 is at the top, connected by a vertical line to ITU-T K.87. ITU-T K.87 is connected by a horizontal line to a vertical line that branches out to five items: ITU-T K.78 (High altitude electromagnetic pulse immunity), ITU-T K.81 (High-power electromagnetic immunity), ITU-T K.84 (Information leaks through electromagnetic emissions), ITU-T K.43, ITU-T K.48, etc. (Immunity and emission), and ITU-T K.20, ITU-T K.21, ITU-T K.44, ITU-T K.45, etc. (Lightning protection). A separate horizontal line from the main vertical line of ITU-T K.87 points to ITU-T K.115 (Mitigation methods against electromagnetic security threats). + +K.87(16)\_F01 + +**Figure 1 – The relationship between security Recommendations** + +**Table 1 – EM security problems considered in this Recommendation** + +| Phenomena | | Category of security problem | Relevant ITU-T Recommendation | | +|------------------------------------|------------------------|------------------------------|--------------------------------------------------------------|---------------| +| | | | Requirements | Mitigation | +| Electromagnetic Interference (EMI) | Intentional EMI (IEMI) | HEMP | [ITU-T K.78] | [ITU-T K.115] | +| | | HPEM | [ITU-T K.81] | | +| | Natural EMI | Immunity and emission | [ITU-T K.43], [ITU-T K.48], etc. | | +| | | Lightning protection | [ITU-T K.20], [ITU-T K.21], [ITU-T K.44], [ITU-T K.45], etc. | | +| Information leakage | | EMSEC | [ITU-T K.84] | | + +EMI: Electromagnetic interference +HEMP: High-altitude electromagnetic pulse +HPEM: High-power electromagnetic +EMSEC: Electromagnetic emanation security + +## 6.2 Lightning + +### 6.2.1 Introduction + +Cloud to ground lightning strikes can produce high voltage surges into power and telecommunication lines by electromagnetic induction. Lightning strikes to buildings or to ground near buildings or cables can produce surges by conductive coupling into power and telecommunication circuits. These surges may cause damages in telecommunication equipment. To ensure a reliable telecommunication service, it is necessary to ensure that the equipment has an adequate level of resistibility to protect it from the majority of inductively coupled high voltage surges and protect it against the majority of higher energy surges by the installation of lightning protection measures external to the equipment. The equipment shall comply with the appropriate resistibility Recommendations listed in clause 6.1.2 below to achieve this. + +### 6.2.2 Relation to the reference documents + +The three product resistibility Recommendations, [ITU-T K.20], [ITU-T K.21] and [ITU-T K.45], provide the requirements for lightning, power induction and power contact tests. Two levels of requirements are provided: "basic level" and "enhanced level". Guidance on the application of the basic and enhanced levels is given in [ITU-T K.44]. [ITU-T K.44] contains common information + +relevant to the three product recommendations including test methods and test configurations with schematics. + +[ITU-T K.40] presents the guidelines for the design of an effective protective system structure against lightning electromagnetic pulse (LEMP) applicable to structures for telecommunication centre. The concept of lightning protection zones is introduced as a framework where the specific protective measures, such as earthing, bonding, cable routing and shielding are merged. Information about simulation of the LEMP effects and the options of the protective measures applicable to existing and newly planned buildings are also given. + +## 6.3 Intentional electromagnetic interference + +As the value of information has increased in recent years, so too has the value and importance of information security. Information is increasingly being integrated into data strongholds, which require ever more formidable methods to resist attacks such as cyber terror. + +When strong electromagnetic fields are applied intentionally from a distance to target electronic devices or systems, such as ICT equipment or transmission systems, malfunctions or more serious damages of the elements or circuits could result. + +Intentional electromagnetic interference (IEMI) is the term applied to the intentional generation of strong electromagnetic energy aiming to introduce interferences to IT equipment. Lightning is not classified to IEMI, because it occurs unintentionally. The IEMI threat is classified to two types: high-power electromagnetic (HPEM) and high-altitude electromagnetic pulse (HEMP) threats. HEMP is the term applied to the electromagnetic pulse produced by a nuclear explosion at high-altitude atmosphere, typically above an altitude of 30 km. HPEM is the term applied to an intentionally produced strong electromagnetic radiated field or conducted voltages and currents with a peak power which has the capability to damage or upset electronic systems. There are many kinds of devices that generate such strong electromagnetic waves, including illegal devices, appearing on the market. For example, devices that can radiate high power electromagnetic waves including citizen band (CB) radio equipment, amateur radio equipment, navigation radars, microwave ovens, and devices that create high voltage static electricity include stun guns. Also, compact lightning-surge-generators and continuous wave (CW) generators with amplifier used generally in test labs can generate electromagnetic waves or can be used to generate conducted interferences by way of metal wires. These threats are classified as radiated and conducted threats according to the propagation paths from HPEM sources to ICT equipment. Examples are shown in Table 2. + +**Table 2 – Examples of propagation paths and threat** + +| | | +|-----------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Electromagnetic wave attack – radiated | Attack by applying strong electromagnetic waves using a high-power wireless device, microwave generator, radar, etc. | +| Electromagnetic wave attack – conducted | Attack by applying high voltage/current waves directly to communication lines or power lines using a compact lightning-surge generator, high-power CW generator, etc. | + +The threat of IEMI is evaluated by several factors, i.e., portability of an EMI generation device, an intrusion area and availability in terms of required cost and technical level. It is necessary to perform risk evaluation and classify the level of threat in order to determine adequate countermeasures against IEMI in each case. + +## 6.4 High-altitude electromagnetic pulse (HEMP) + +### 6.4.1 Introduction + +HEMP is the term applied to the electromagnetic pulse produced by a nuclear explosion at high-altitude. In this context, "high altitude" is typically above 30 km, such that other physical effects associated with a nuclear detonation are not present at ground level. + +HEMP generates an electromagnetic pulse that contains both a radiated component (due to the detonation itself) and a conducted component (due to the coupling of the radiated environment with exposed, overhead cables and subsequent propagation along the cable). + +A high-altitude nuclear detonation acts as a point source from which a spherical wave-front propagates, at the speed of light, from the point of detonation towards the surface of Earth. This wave-front is, depending upon altitude, able to illuminate a large section of the Earth's surface. An example of this phenomenon is illustrated in Figure 2, which shows the electromagnetic field at the ground level produced by the detonation of a 200 kt nuclear explosive at an altitude of 300 km. + +![Figure 2: A map of Europe and the surrounding seas showing the effects of a high-altitude nuclear explosion. Concentric white circles represent the wavefronts of the electromagnetic pulse, centered on a point in the North Atlantic. The map shows landmasses in blue and brown, with numerous orange dots representing cities or towns. The text '200 kt Nuclear Explosion' is visible near the center of the wavefronts.](bafe3c344aef7f6f79dab49c9eca89a9_img.jpg) + +Figure 2: A map of Europe and the surrounding seas showing the effects of a high-altitude nuclear explosion. Concentric white circles represent the wavefronts of the electromagnetic pulse, centered on a point in the North Atlantic. The map shows landmasses in blue and brown, with numerous orange dots representing cities or towns. The text '200 kt Nuclear Explosion' is visible near the center of the wavefronts. + +**Figure 2 – Example of a HEMP event** + +Precise figure of the typical variations in peak incident E1 HEMP electric fields is shown in Figure 6 of [IEC 61000-2-9]. For a 300 km burst height, the range to the outer circle should be ~1900 km. The location of the 0.75 Emax contour to the South of the burst is at a range of 4.2 times of the height of burst (HOB) or 1260 km. The outer circle should be at a range of 1900 km or nearly 6.3 times of HOB given the scale. + +HEMP consists of three separate and distinct pulses that are produced by different mechanisms (see Figure 3, originally from Figure 10 in [IEC 61000-2-9]). + +![Figure 3: Pulse characteristics. A log-log plot showing electric field strength E(t) in V/m versus time in seconds. The y-axis ranges from 10^-4 to 10^5 V/m, and the x-axis ranges from 10^-11 to 10^3 seconds. Three pulses are shown: E1(t) is a very sharp, high peak reaching approximately 10^4 V/m at around 10^-9 seconds. E2(t) is a broader, lower peak reaching approximately 10^2 V/m at around 10^-7 seconds and lasting until about 10^-3 seconds. E3(t) is a very broad, low peak reaching approximately 10^-1 V/m at around 10^1 seconds and lasting until about 10^2 seconds. A dashed line indicates a reversed sign for the tail of the E3(t) pulse. The plot is labeled K.87(16)_F03.](71ab4df17511d75261da8d462d643b1a_img.jpg) + +Figure 3: Pulse characteristics. A log-log plot showing electric field strength E(t) in V/m versus time in seconds. The y-axis ranges from 10^-4 to 10^5 V/m, and the x-axis ranges from 10^-11 to 10^3 seconds. Three pulses are shown: E1(t) is a very sharp, high peak reaching approximately 10^4 V/m at around 10^-9 seconds. E2(t) is a broader, lower peak reaching approximately 10^2 V/m at around 10^-7 seconds and lasting until about 10^-3 seconds. E3(t) is a very broad, low peak reaching approximately 10^-1 V/m at around 10^1 seconds and lasting until about 10^2 seconds. A dashed line indicates a reversed sign for the tail of the E3(t) pulse. The plot is labeled K.87(16)\_F03. + +NOTE – New information regarding $E_3(t)$ , [b-Edward], has raised the IEC peak field recommendation to $\sim 0.1$ V/m. + +**Figure 3 – Pulse characteristics** + +The first pulse, referred to as the "early-time HEMP ( $E_1$ )" pulse ( $E_1$ in Figure 3), is generated by the high-energy gamma-rays produced during the detonation as they undergo Compton scattering by atmospheric atoms. This interaction ionizes the atmospheric atoms, producing a very large number of high-energy electrons that experience the Lorentz force due to the earth's magnetic field. This force causes the high energy electrons to turn coherently and in phase creating a line of transverse currents in the upper atmosphere and hence radiate electromagnetic energy. The electromagnetic energy of early time HEMP arrives at ground-level. This pulse has the following characteristics: + +- a very rapid rise time (of the order of a few nanoseconds, i.e., $\sim 10^{-9}$ s); +- a ground-level electric field amplitude up to 50 kV/m beneath the detonation; +- a very short duration (of the order of hundreds of nanoseconds, i.e., $\sim 100 \times 10^{-9}$ s). + +The second pulse, referred to as the "intermediate time HEMP ( $E_2$ )" pulse ( $E_2$ in Figure 3), is also generated by the Compton scattering of gamma-rays by atmospheric atoms, but involves comparatively lower-energy interactions that take place after the initial, hugely energetic phase associated with the nuclear detonation. This pulse has the following characteristics: + +- a much slower rise time (of the order of a few hundreds of nanoseconds, i.e., $\sim 100 \times 10^{-9}$ s); +- a ground-level electric field amplitude up to 100 V/m directly beneath the detonation; +- a much longer duration (of the order of tens of milliseconds, i.e., $\sim 10 \times 10^{-3}$ s). + +The third pulse, referred to as the "late time HEMP ( $E_3$ )" ( $E_3$ in Figure 3), is essentially similar to the phenomena that has been observed in the higher northern latitudes in response to geomagnetic storms in the upper atmosphere due to solar storm. The high-altitude nuclear detonation induces the flow of currents in the upper atmosphere to behave in a manner similar to the phenomena observed during a geomagnetic storm. This pulse has the following characteristics: + +- a much slower rise time (of the order of a few seconds, i.e., $\sim 1$ s); +- a ground-level electric field amplitude up to 10 mV/m directly beneath the detonation (see Note) +- a much longer duration (of the order of hundreds of seconds, i.e., $\sim 100$ s). + +NOTE – New information regarding $E_3(t)$ [b-Edward] shows a ground-level electric field amplitude up to 100 mV/m directly beneath the detonation. + +Table 3 shows examples of evaluated HEMP threat. + +Detailed environment description is in [IEC 61000-2-9]. [61000-2-10] and [61000-2-11]. + +**Table 3 – Example of evaluated threat related to HEMP** + +| Threat type | Example of attack device | Strength | Wave form/frequency range | +|-------------|-------------------------------------|--------------|---------------------------| +| HEMP attack | Radiation (early-time HEMP) | 50 kV/m peak | 2.5/23 ns/1 MHz-200 MHz | +| | Conduction (intermediate-time HEMP) | 20 kV peak | 125/1500 µs, 1 kHz-1 MHz | + +### 6.4.2 Relation to the reference documents + +[ITU-T K.78] provides the radiated and conducted immunity requirements for telecommunication equipment such as switching, transmission, radio, and power installed in telecommunication centres against a high-altitude electromagnetic pulse (HEMP). + +[ITU-T K.78] contains immunity test methods and levels for telecommunication equipment in each installation condition. + +## 6.5 High-power electromagnetic (HPEM) + +### 6.5.1 Introduction + +HPEM is the term applied to the intentionally produced electromagnetic phenomena created by high-power electromagnetic (HPEM) sources. These sources are discussed in the [IEC 61000] series standards listed in clause 2. IEC standard, technical report and technical standard are published for HPEM threats as shown in Table 4; and also related deliverables are published under the responsibility of [IEC SC 77C]. + +**Table 4 – Standards and summaries related to HPEM of the IEC 61000-x series** + +| Standard number | Standard name | Description and summary | +|---------------------|----------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| [IEC TR 61000-1-5] | High-power electromagnetic (HPEM) effects on civil systems | Example of the effects (HPEM) of high-power electromagnetic waves on civil systems, and a summary of test results. | +| [IEC 61000-2-13] | High-power electromagnetic (HPEM) environments – radiated and conducted | Description of HPEM environments, summary of generating devices, definition of waveforms, etc. | +| [IEC TR 61000-4-35] | HPEM simulator compendium | Information about extant system-level High-Power Electromagnetic (HPEM) simulators and their applicability as test facilities, etc. | +| [IEC 61000-4-36] | IEMI immunity test methods for equipment and systems. Basic EMC publication | This standard provides methods to determine test levels for the assessment of the immunity of equipment and systems to intentional electromagnetic interference (IEMI) sources. It introduces the general IEMI problem, IEMI source parameters, derivation of test limits and summarizes practical test methods. | +| [IEC 61000-5-9] | Installation and mitigation guidelines - System-level susceptibility assessments for HEMP and HPEM | It provides information on available methods for the assessment of system-level susceptibility as a result of HEMP and HPEM environments. | + +[IEC TR 61000-1-5] provides an example of HPEM and describes the background for research of HPEM, introduces HPEM generators and provides summaries of test results on devices such as personal computers (PCs). In conduction, a lightning-surge generation is included as an HPEM generator. Further, Chapter 7 of [IEC TR 61000-1-5] touches on countermeasure concepts and describes countermeasure methods such as shielding and surge-voltage protection, as well as the existence of alternative countermeasure methods such as active protection or system degeneration, error detection and error collection software. + +In [IEC 61000-2-13] the importance of reviewing the HPEM process is clearly explained as follows: + +"A threat environment is provided by an artificially caused high-power electromagnetic wave (HPEM). That kind of threat environment can give large damage to consumer electrical equipment and electronic devices as described in [IEC TR 61000-1-5]. In order to establish protection methods, it is necessary to define radiation and conduction environments." + +Various kinds of radiation HPEM generators and examples of waveforms are also described in Chapter 5 of [IEC 61000-2-13], and the threat due to conduction is explained in Chapter 6 of [IEC 61000-2-13]. Examples of the electric field intensity of some types of HPEM generators are given in Annex B of [IEC 61000-2-13]. + +The IEC 61000 series documents listed in clause 2 and [ITU-T K.81] guide immunity requirements for telecommunication systems. + +In [ITU-T K.81] HPEM threats are classified by particular factors, i.e., threat portability level, the intrusion area and availability levels; they are also defined in [ITU-T K.81]. Classifications of threat and associated examples are described in clause 5 of [ITU-T K.81]. Table 5 (originally from Table 5.4-1 in [ITU-T K.81]) shows calculation examples of HPEM threat. + +**Table 5 – Evaluated threat of examples of HPEM devices** + +| Threat type | HPEM device | Strength | Frequency range | +|-------------------------------|-------------------------------------------------|--------------------------|--------------------------| +| Radiated electromagnetic wave | IJOLT | 172 kV/m@100 m | 350 MHz-2 GHz | +| | Impulse radiating antenna (IRA) (hi-technology) | 12.8 kV/m@100 m | 300 MHz-10 GHz | +| | Commercial radar (mid-technology) | 60 kV/m@100 m | 1 GHz-10 GHz (1.285 GHz) | +| | Navigation radar | 385 V/m@100 m | 1 GHz-10 GHz (9.41 GHz) | +| | Magnetron generator | 475 V/m@10 m | 1 GHz-3 GHz | +| | Amateur wireless device | 286 V/m@1 m | 100 MHz-3 GHz | +| | Amateur wireless device | 169 V/m@10 cm | 100 MHz-3 GHz | +| | Illegal CB radio | 573 V/m@10m | 27 MHz | +| Electrostatic discharge | Stun gun | 500 kV | 100 MHz-3 GHz | +| Conducted disturbance | Lightning-surge generator | 50 kV (charging voltage) | 1.2/50 µs
10/700 µs | +| | Compact lightning-surge generator | 10 kV (charging voltage) | 1.2/50 µs
10/700 µs | +| | CW generator | 100 V~240 V/4 kV | 1 Hz-10 MHz | +| | Commercial power supply | 100 V~240 V | 50/60 Hz | + +Threat mitigation levels against HPEM attack are defined in clause 6 of [ITU-T K.81], considering both HPEM threat and vulnerability levels. Examples of mitigation levels for some HPEM devices are also presented. + +Examples of HPEM threat and vulnerability that use impulse radiating antenna (IRA) with the repetitive high impulse generator discussed in [b-Baum 2004], are described in detail in Appendix I of [ITU-T K.81]. + +### **6.5.2 Relation to the reference documents** + +[ITU-T K.81] provides the radiated and conducted immunity requirements for telecommunication equipment such as switching, transmission, radio, and power installed in telecommunication centres against a high-power electromagnetic (HPEM). + +[ITU-T K.81] contains immunity test methods and levels for telecommunication equipment in each installation condition. [ITU-T K.115] also provides mitigation methods for the threats of an HPEM. [b-CIGRE C4.206] provides the mitigation methods for power stations and so on. + +## **6.6 Information leakage** + +### **6.6.1 Introduction** + +Electronic equipment usually emit unintentional electromagnetic waves, and some of these emissions may carry important information processed inside the equipment. This emitted information can often be stolen by intercepting such emissions from a distance. + +This Recommendation gives guidance to reduce the threats from such information leakage due to unintentional electromagnetic emanation from information equipment at telecommunication centres managed by an information security management system (ISMS). + +EMSEC is the term applied to the information leakage due to unintentional electromagnetic emission in this Recommendation. Threat of EMSEC is considerable for many kinds of equipment such as personal computers, data servers, laser printers, keyboards, and cryptographic modules. This Recommendation only treats information leakage from equipment that includes raster scan video signal. Further study is required of equipment involving other kinds of leaked signals. + +Two approaches to protect against threats are given in this Recommendation: + +- 1 emission requirements and methods of examining equipment are applied when the equipment cannot be installed in the shielding site (the shielding site should reduce the emissions of the equipment); +- 2 shielding requirements for sites such as buildings are applied when the equipment can be installed at secure sites. + +EMSEC threats are determined according to comparisons of the confidentiality and threat levels as given in clause 5 of [ITU-T K.84]. The threat level is determined by intrusion range, portability, and availability of the threat devices. The threat of EMSEC is described in Appendix I of [ITU-T K.84]. The confidentiality level of the equipment, which is evaluated with existing EMC standards, is presented in Appendix II of [ITU-T K.84]. Examples of threats against EMSEC are summarized in Table 6 (originally Table 5.1-1 of [ITU-T K.84]). Definitions of threats related to portability levels and threat availability levels are presented in Tables 7 and 8 (originally, Tables 5.1-2 and 5.1-3 of [ITU-T K.84]). The availability level shall be thought of as a measure of both the cost and the technological sophistication of the threat devices such as receivers, antenna, etc. + +**Table 6 – Examples of threats related to information leakage** + +| Types of threats | Examples of receiver | Possible distance for EMSEC | | Threat level | | | Threat number | +|------------------|------------------------------|-------------------------------|-------------------------------|--------------------------------|-------------|--------------|---------------| +| | | Confidentiality level Class A | Confidentiality level Class B | Intrusion range on attack side | Portability | Availability | | +| EMSEC | Special receiver | 330 m a) | 105 m a) | Zone 0 | PIII | AIV | K4-1 | +| | Special receiver | 330 m a) | 105 m a) | Zone 1 | PIII | AIV | K4-2 | +| | General-purpose EMC receiver | 59 m a)
263 m | 19 m a)
83 m | Zone 1 | PII | AIII | K4-3 | +| | General-purpose EMC receiver | 59 m a)
263 m | 19 m a)
83 m | Zone 2 | PII | AIII | K4-4 | +| | Amateur receiver | 33 m a)
148 m | 11 m a)
47 m | Zone 1 | PII | AII | K4-5 | +| | Amateur receiver | 33 m a)
148 m | 11 m a)
47 m | Zone 2 | PII | AII | K4-6 | +| | Amateur receiver | 33 m a)
148 m | 11 m a)
47 m | Zone 3 | PII | AII | K4-7 | + +a) Assumed to have reinforced concrete walls with 13 dB attenuation. + +**Table 7 – Definitions of threat portability levels** + +| Threat portability level | Definition | +|--------------------------|---------------------------------------| +| PI | Pocket-sized or body-worn (Note 1) | +| PII | Briefcase or back-pack sized (Note 2) | +| PIII | Motor-vehicle sized (Note 3) | +| PIV | Trailer-sized (Note 4) | + +NOTE 1 – This portability level applies to threat devices that can be hidden in the human body and/or in the clothing. + +NOTE 2 – This portability level applies to threat devices that are too large to be hidden in the human body and/or in the clothing, but still small enough to be carried by a person (such as in a briefcase or a back-pack). + +NOTE 3 – This portability level applies to threat devices that are too large to be easily carried by a person, but small enough to be hidden in a typical consumer motor vehicle. + +NOTE 4 – This portability level applies to threat devices that are too large to be either easily carried by a person or hidden in a typical consumer motor vehicle. Such threat devices require transportation using a commercial/industrial transportation vehicle. + +**Table 8 – Definitions of threat availability levels** + +| Availability level | Definition | Examples | +|--------------------|----------------|------------------------------| +| AI | "Consumer" | | +| AII | "Hobbyist" | Amateur receiver | +| AIII | "Professional" | General-purpose EMC receiver | +| AIV | "Bespoke" | Special receiver | + +As shown in Table 6, when the threat level is assumed to be AII (amateur receiver level) and the confidentiality level is assumed to be Class B, for example, and the threat device never gets closer than 47 m, security is well managed. Therefore, no additional mitigation is necessary. + +Where the possibility is high that the threat device will get closer, e.g., when the customer must operate the equipment near a window or it is installed near a window, the presence of information leakage due to unintentional electromagnetic radiation should be assessed. The security requirement level of equipment is described in clause 5.3 of [ITU-T K.84], and the test method is explained in Annex A of [ITU-T K.84]. + +Where the possibility is low that the threat device will get closer, e.g., the equipment is installed at a secure site and it is surrounded by walls, the walls separate the distance between the equipment and the threat device. Confidentiality can be maintained with a shield and the use of equipment, which is explained in existing EMC emission standards. The level of security requirements for shielding is described in clause 5.4 of [ITU-T K.84]. + +### 6.6.2 Relation to the reference documents + +[ITU-T K.84] provides guidance to reduce the threats from information leakage due to EMSEC of information equipment at telecommunication centres. [ITU-T K.115] also provides mitigation methods for information leakage from information equipment. + +[ITU-T K.84] describes threats and confidentiality related to EMSEC, and two approaches to mitigation methods. The first approach involves emission requirements for equipment and the second involves shielding requirements for sites, when equipment that is examined with existing EMC emission standards such as [ITU-T K.48] and [CISPR 32] is installed at a site. + +[ITU-T K.84] also provides a method of testing EMSEC for radiation in its Annex A and for conductive coupling in its Annex B. Examples of measurement methods, wideband measurement, and narrowband measurement, are presented in Appendix III and Appendix IV of [ITU-T K.84]. + +## Bibliography + +### ITU security + +- [b-ITU-T X800] Recommendation ITU-T X.800 (1991), *Security architecture for Open Systems Interconnection for CCITT applications*. +- [b-NIST-SP-800-30] NIST Special Publication 800-30, 2012, *Guide for Conducting Risk Assessments*. +- [b-ITU-T Handbook] ITU-T Handbook (2006), *Security in Telecommunications and Information Technology – An overview of issues and the deployment of existing ITU-T Recommendations for secure telecommunications*. + +### IEC EMC + +- [b-IEC 60050-161] IEC 60050-161: 1990, *International Electrotechnical Vocabulary (IEV) – Chapter 161: Electromagnetic compatibility*. + +### Standards related to ICT security + +- [b-CISPR 17] CISPR 17:2011, *Methods of measurement of the suppression characteristics of passive EMC filtering devices*. +- [b-IETF RFC 2828] IETF RFC 2828:2000, *Internet Security Glossary*. +- [b-ISO/IEC 15408-1] ISO/IEC 15408-1: 2022, *Information security, cybersecurity and privacy protection – Evaluation criteria for IT security – Part 1: Introduction and general model*. +- [b-ISO/IEC 15408-2] ISO/IEC 15408-2: 2022, *Information security, cybersecurity and privacy protection – Evaluation criteria for IT security – Part 2: Security functional components*. +- [b-ISO/IEC 15408-3] ISO/IEC 15408-3:2022, *Information security, cybersecurity and privacy protection – Evaluation criteria for IT security – Part 3: Security assurance components*. +- [b-ISO/IEC 19790] ISO/IEC 19790:2012, *Information technology – Security techniques – Security requirements for cryptographic modules*. +- [b-ISO/IEC 27000] ISO/IEC 27000:2018, *Information technology – Security techniques – Information security management systems – Overview and vocabulary*. +- [b-ISO/IEC 27001] ISO/IEC 27001:2022, *Information security, cybersecurity and privacy protection – Information security management systems – Requirements*. +- [b-ISO/IEC 27002] ISO/IEC 27002:2022, *Information security, cybersecurity and privacy protection – Information security controls*. + +### Other standards related to shield measurement methods + +- [b-IEC 61587-3] IEC TS 61587-3:2013, *Mechanical structures for electronic equipment – Tests for IEC 60917 and IEC 60297 – Part 3: Electromagnetic shielding performance tests for cabinets and subracks*. +- [b-IEEE 299] IEEE Std 299-2006, *IEEE Standard Method for Measuring the Effectiveness of Electromagnetic Shielding Enclosures*. + +### Other documents + +- [b-IEC Glossary] + +- [b-NEBS GR-1089] Telcordia Technologies NEBS GR-1089 (2011), *Electromagnetic Compatibility and Electrical Safety – Generic Criteria for Network Telecommunications Equipment*. +- [b-NEBS SR-3580] Telcordia Technologies NEBS SR-3580 (2012), *Criteria Levels*. +- [b-NTT TR 549001] Nippon Telegraph and Telephone Corporation TR 549001 (2023), *Technical requirements for immunity of telecommunications equipment*. + +### HEMP documents + +- [b-Agrawal] Agrawal, A., Price, J., Gurbaxani, S. 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(1989), *Experimental Determination of the Effects of Steep Front-Short Duration Surges on 25 kVA Pole Mounted Distribution Transformers*, IEEE Transactions on Power Delivery, Vol. 4, No. 2, April; pp. 1103-1110. +- [b-Ellis] Ellis, V., HDL-TR-2149 (1989), *Consumer Electronics Testing to Fast-Rise EMP (VEMPS II Development)*, Adelphi, MD, Harry Diamond Laboratories. +- [b-Glasstone] Glasstone, S., Dolan P. (1977), *The Effects of Nuclear Weapons*, Washington, DC, U.S. Department of Defense and Department of Energy. +- [b-Greetesai] Greetesai, V.N., *et al.* (1998), *Response of Long Lines to Nuclear High-Altitude Electromagnetic Pulse (HEMP)*, IEEE Transactions on EMC, Vol. 40, No. 4, November; pp. 348-354. +- [b-Hansen] Hansen, D., *et al.* (1990), *Response of an Overhead Wire Near a NEMP Simulator*, IEEE Transactions on EMC, Vol. 32, No. 1, February; pp. 18-27. +- [b-Ianoz] Ianoz, M., *et al.* (1993), *Response of Multiconductor Power Lines to Close Indirect Lightning Strokes*, Proceedings of the CIGRE Symposium, Power System Electromagnetic Compatibility, Lausanne. +- [b-IEC 61000-1-3] IEC TR 61000-1-3:2002, *Electromagnetic compatibility (EMC) – Part 1-3: General – The effects of high-altitude EMP (HEMP) on civil equipment and systems*. +- [b-Imposimato] Imposimato, C., *et al.* (1999), *Evaluation of the radiated lightning coupling on real MV power lines by an EMP Simulator*, 13th International Zurich Symposium on EMC. + +- [b-Loborev] Loborev, V. 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(1992), *Maximization of Electromagnetic Response at a Distance*, IEEE Transactions on EMC, Vol. 34, No. 3, August; pp. 148-153. +- [b-Baum 2002] Baum, C.E., Lehr, J.M. (2002), *Tapered Transmission-Line Transformers for Fast High-Voltage Transients*, IEEE Transactions on Plasma Science, Vol. 30, No. 5, October; pp. 1712-1721. +- [b-Baum 2004] Baum, C.E., *et al.* (2004), *JOLT: A Highly Directive, Very Intensive, Impulse-Like Radiator*, Proceedings of the IEEE, Vol. 92, No. 7, July; pp. 1096-1109. +- [b-Giri] Giri, D.V., *et al.* (2000), *Intermediate and Far Fields of a Reflector Antenna Energized by a Hydrogen Spark-Gap Switched Pulser*, IEEE Transactions on Plasma Science, Vol. 28, No. 5, October; pp. 1631-1636. +- [b-Ianoz] Ianoz, M., Nicoara, B.I.C, Radasky, W.A. (1996), *Modeling of an EMP Conducted Environment*, IEEE Transactions on EMC, Vol. 38, No. 3, August; pp. 400-413. +- [b-Mikheev] Mikheev, O.V., *et al.* (1997), *New Method for Calculating Pulse Radiation from an Antenna With a Reflector*, IEEE Transactions on Electromagnetic Compatibility, Vol. 39, No. 1, pp. 48-54. +- [b-Prather] Prather, W.D., *et al.* (2000), *Ultra-Wideband Source and Antenna Research*, IEEE Transactions on Plasma Science, Vol. 28, No. 5, October; pp. 1624 1630. +- [b-Silfverskiold 1999] Silfverskiold, S., *et al.* (1999), *Induced Voltages in a Low-Voltage Power Installation Network Due to Lightning Electromagnetic Fields: An Experimental Study*, IEEE Transactions on Electromagnetic Compatibility, Vol. 41, No. 3, August; pp. 265-271. +- [b-Silfverskiold 2002] Silfverskiold, S., *et al.* (2002), *Microwave Field-to-Wire Coupling Measurements in Anechoic and Reverberation Chambers*, IEEE Transactions on Electromagnetic Compatibility, Vol. 44, No. 1, February; pp. 222-232. +- EMSEC documents** +- [b-5200.28-STD] 5200.28-STD (1985), *Trusted Computer System Evaluation Criteria*, Washington, DC, United States Department of Defense. + +- [b-Kuhn 2011] Kuhn, M.G. (2011), *Compromising Emanations of LCD TV Sets*, Proceedings of the IEEE International Symposium on Electromagnetic Compatibility, 14-19 August; pp. 931-936. +- [b-Kuhn 1998] Kuhn, M.G., Anderson, R.J. (1998), *Soft Tempest: Hidden Data Transmission Using Electromagnetic Emanations*, Proceedings of the Second International Workshop on Information Hiding, Portland, Oregon, 14-17 April; pp. 124-142. +- [b-Loughry] Loughry J., Umphress, D.A. (2002), *Information Leakage from Optical Emanations*, ACM Transactions on Information and System Security, Vol. 5, No. 3, August; pp. 262-289. +- [b-MIL-HDBK-232] MIL-HDBK-232 Rev A (1987), *Red/Black Engineering-Installation Guidelines*, Washington, DC, United States Department of Defense. +- [b-Sekiguchi 2009a] Sekiguchi, H., Seto, S. (2009), *Measurement of Radiated Computer RGB Signals*, Progress In Electromagnetics Research C, Vol. 7, pp. 1-12. +- [b-Sekiguchi 2009b] Sekiguchi, H., Seto, S (2009), *Measurement of Computer RGB Signals in Conducted Emission on Power Leads*, Progress In Electromagnetics Research C, Vol. 7, pp. 51-64. +- [b-Sekiguchi 2011] Sekiguchi, H., Seto, S. (2011), *Estimation of Receivable Distance for Radiated Disturbance Containing Information Signal from Information Technology Equipment*, Proceedings of the IEEE International Symposium on Electromagnetic Compatibility, 14-19 August; pp. 942-945. +- [b-Smulders] Smulders, P. (1990), *The threat of information theft by reception of electromagnetic radiation from RS-232 cables*, Computers and Security, Vol. 9, No.1, January; pp. 53-58. +- [b-Tosaka] Tosaka, T., Yamanaka, Y., Fukunaga, K. (2010), *Evaluation method of information in electromagnetic disturbance radiated from PC display using time varying stripe image*, Proceedings of the 4th Pan-Pacific EMC Joint Meeting, May; pp. 67–70. +- [b-Van Eck] Van Eck, W. (1985), *Electromagnetic radiation from video display units: An eavesdropping risk?* Computers and Security, Vol 4, No. 4, December; pp. 269-286. +- [b-Watanabe] Watanabe, T., Franke, K., Sako, H. (2011), *Towards Large-scale EM-leakage Evaluation by means of Automated TOE Synchronization*, Proceedings of the IEEE International Symposium on Electromagnetic Compatibility, 14-19 August; pp. 937-941. + +### **EMSEC documents (side-channel attacks)** + +- [b-Hayashi] Hayashi, Y., *et al.* (2011), *Non-Invasive EMI-Based Fault Injection Attack against Cryptographic Modules*, Proceedings of the IEEE International Symposium on Electromagnetic Compatibility, 14-19 August; pp. 763-767. +- [b-Ikematsu] Ikematsu, T., *et al.* (2011), *Suppression of Information Leakage from Electronic Devices Based on SNR*, Proceedings of the IEEE International Symposium on Electromagnetic Compatibility, 14-19 August; pp. 920-924. +- [b-Iokibe] Iokibe, K., *et al.* (2011), *On-Board Decoupling of Cryptographic FPGA to Improve Tolerance to Side-Channel Attacks*, Proceedings of the IEEE + +International Symposium on Electromagnetic Compatibility, 14-19 August; pp. 925-930. + +- [b-Meynard] Meynard, O., *et al.* (2011), *Identification of Information Leakage Spots on a Cryptographic Device with an RSA Processor*, Proceedings of the IEEE International Symposium on Electromagnetic Compatibility, 14-19 August; pp. 773-778. +- [b-Sauvage] Sauvage, L., *et al.* (2011), *Practical Results of EM Cartography on a FPGA-based RSA Hardware Implementation*, Proceedings of the IEEE International Symposium on Electromagnetic Compatibility, 14-19 August; pp. 768-772. + +### **Standards for video display units** + +- [b-VESA 1999] VESA (1999), *Generalized Timing Formula (GTF)*, Version 1.1, Milpitas, CA, Video Electronics Standards Association. +- [b-VESA 2007] VESA (2007), *VESA and Industry Standards and Guidelines for Computer Display Monitor Timing (DMT)*, Version 1.0, Milpitas, CA, Video Electronics Standards Association. + +### **IST in Japan** + +- [b-IST SG] Information Security Technology Study Group website. + + + + + +### SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.89-201205-I_PDF-E/raw.md b/marked/K/T-REC-K.89-201205-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..5b886a950e52d6a1beea1b48c3e1d3eec37eaeb1 --- /dev/null +++ b/marked/K/T-REC-K.89-201205-I_PDF-E/raw.md @@ -0,0 +1,1490 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.89** + +(05/2012) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Protection of persons inside a structure using +telecommunication services provided by +metallic conductors against lightning – Risk +management** + +Recommendation ITU-T K.89 + + + +# Recommendation ITU-T K.89 + +# Protection of persons inside a structure using telecommunication services provided by metallic conductors against lightning – Risk management + +## Summary + +Recommendation ITU-T K.89 gives the methodology for evaluating the need to protect users of telecommunication equipment in structures and that of building occupants related to the telecommunication installation. + +This method is based on a risk assessment: protection measures are necessary when the risk is greater than the tolerable risk. A maximum value of the tolerable risk is suggested. + +The risk is evaluated using the lightning risk components which can be a source of injury to telecommunication service users and building occupants (lightning flashes direct to the line or to the structures connected at the ends of the line). + +The risk assessment is done according to Edition 2 of IEC 62305-2. A simple risk assessment is provided to enable the telecommunication network operator to decide when to install gas discharge tubes (GDTs) at the point of entry of the telecommunication line into the structure independent of the structure attributes. This Recommendation can be used together with Recommendation ITU-T K.47, which provides a more accurate risk assessment of lightning flashes directly to the telecommunication line, and IEC 62305-2, which provides the risk assessment of lightning flashes to the structure. + +## History + +| Edition | Recommendation | Approval | Study Group | +|---------|----------------|------------|-------------| +| 1.0 | ITU-T K.89 | 2012-05-29 | 5 | + +## Keywords + +Lightning, node, protection, risk, risk assessment, surge, SPD, telecommunication line. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2012 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | | Page | +|-----|-----------------------------------------------------------------------------------------------|------| +| 1 | Scope | 1 | +| 2 | References | 1 | +| 3 | Definitions | 2 | +| 3.1 | Terms defined elsewhere | 2 | +| 3.2 | Terms defined in this Recommendation | 2 | +| 4 | Abbreviations and acronyms | 4 | +| 5 | Reference configuration | 4 | +| 6 | Explanation of terms | 5 | +| 6.1 | Damage and loss | 5 | +| 6.2 | Risk and risk components | 7 | +| 6.3 | Composition of risk components related to a structure | 8 | +| 7 | Risk management | 9 | +| 7.1 | Basic procedure | 9 | +| 7.2 | Tolerable risk R T | 9 | +| 7.3 | Specific procedure to evaluate the need for protection | 9 | +| 7.4 | Protection measures | 10 | +| 7.5 | Selection of protection measures | 10 | +| 8 | Responsibility | 13 | +| | Annex A – Assessment of annual number $N$ of dangerous events | 14 | +| A.1 | Assessment of the average annual number of dangerous events $N_L$ due to
flashes to a line | 14 | +| | Annex B – Assessment of probability $P_x$ of damage for a structure | 15 | +| B.1 | Probability PA | 15 | +| B.2 | Probability PB | 15 | +| B.3 | Probability PC | 15 | +| B.4 | Probability PM | 15 | +| B.5 | Probability PU | 15 | +| B.6 | Probability PV | 16 | +| B.7 | Probability PW | 16 | +| B.8 | Probability PZ | 16 | +| | Annex C – Assessment of amount of loss $L_x$ in a structure | 17 | +| | Appendix I – Example of a risk assessment according to [IEC 62305-2] | 18 | +| I.1 | General | 18 | +| I.2 | Building characteristics | 18 | +| I.3 | Characteristics of the services | 18 | +| I.4 | Characteristics of the internal systems | 20 | +| I.5 | Zones definition in the structure | 21 | + +| | Page | +|-----------------------------------------------------------------------------------------------|------| +| I.6 Expected dangerous events to the structure..... | 22 | +| I.7 Risk assessment for the unprotected structure..... | 23 | +| I.8 Selected protection measures ..... | 23 | +| I.9 Risk assessment related to the protected structure ..... | 24 | +| I.10 SPDs ..... | 24 | +| Appendix II – Equipotential bonding..... | 26 | +| II.1 Non-conductive floors ..... | 26 | +| II.2 Lack of bonding between the telecommunication service, power service
and the MEB..... | 26 | +| Appendix III – Cable routing..... | 27 | +| Appendix IV – Risk assessment using Recommendation ITU-T K.47 ..... | 28 | +| IV.1 Assessment of annual number N of dangerous events ..... | 28 | +| IV.2 Assessment of Factor $P_{LD}$ for shielded cables..... | 29 | +| Appendix V – Mechanisms of damage ..... | 30 | +| V.1 Electric shock ..... | 30 | +| V.2 Fire or explosion..... | 35 | +| Appendix VI – Required current or voltage to cause injury ..... | 36 | +| Bibliography..... | 42 | + +# Introduction + +Lightning flashes to earth may be hazardous to the telecommunication network, the structures at each end of the line and the telecommunication service users. + +The hazard can result in: + +- injury of people inside the structures connected to the telecommunication line; +- physical damage (e.g., cable destruction) to the telecommunication line or structures; +- failure (e.g., insulation breakdown) of the telecommunication line; +- failure of the associated electrical and electronic equipment inside the structure (i.e., exchange, customer's building, or remote electronic site). + +To reduce the loss (due to electric shock, physical injury or failure of internal systems) as a result of lightning flashes, protection measures may be required. Whether they are needed, and to what extent, will be determined by the risk assessment. + +The risk, defined in this Recommendation as the probable average annual loss due to injury as the result of lightning flashes, depends on: + +- the annual number of lightning flashes influencing the structure; +- the probability of damage by one of the influencing lightning flashes; +- the mean amount of consequential loss. + +Lightning flashes influencing the structure may be divided into: + +- flashes direct to a structure connected to the telecommunication line; +- flashes terminating on the telecommunication line entering the structure; +- flashes terminating near the telecommunication line; +- flashes terminating near the structure. + +Flashes direct to a telecommunication line or a structure connected to the telecommunication line may cause physical damage to the structure and the telecommunication line. More importantly, they may cause injury to telecommunication equipment users, cause a fire in the premises or damage equipment, which could immediately endanger life. Flashes near the telecommunication line or the structure may also cause failure of the telecommunication line and of electrical and electronic systems inside the structures. + +The number of lightning flashes influencing the structure depends on the dimensions and the characteristics of the telecommunication network, the characteristics of the structure, on the environment characteristics, as well as on lightning ground flash density in the region where the structure is located. + +The probability of lightning damage depends on the telecommunication network, on the structure, on the lightning current characteristics, as well as on the type and efficiency of applied protection measures. + +The annual mean amount of the consequential loss depends on the extent of damage and the consequential effects which may occur as result of a lightning flash. + +The use of protection will reduce the probability of damage and the amount of consequential loss. + +The assessment of risk due to all possible effects of lightning flashes, to the telecommunication network and the structure, are given in this Recommendation. + +The decision to provide lightning protection may be taken regardless of the outcome of any risk assessment where there is a desire that there be no avoidable risk. + +The boundary between IEC 62305-2 and ITU-T K.89 is that the former deals with the full risk assessment whereas the latter deals with the limitation of dangerous events at the structure from the telecommunication line. The telecommunication network operator can contribute to the customer's protection costs by limiting the number of dangerous events arriving at the customer's structure from the telecommunication line. + +## Recommendation ITU-T K.89 + +# Protection of persons inside a structure using telecommunication services provided by metallic conductors against lightning – Risk management + +# 1 Scope + +This Recommendation deals with the risk management of lightning protection for occupants of a structure related to a telecommunication service using metallic conductor cables. Where the telecommunication service is provided by CDMA WLL, or similar, refer to [ITU-T K.71]. + +The risk assessment is limited to injury of occupants where the installation of the telecommunication service increases the risk of injury due to lightning. This Recommendation provides a procedure for the evaluation of such a risk. Once an upper tolerable limit for the risk has been selected, this procedure allows the selection of appropriate protection measures to be adopted to reduce the risk to a level at or below the tolerable limit. + +This Recommendation is mainly aimed at mitigating the risk associated with a telecommunication service in a private, public or commercial structure. The risks in telecommunication structures are generally mitigated by network operator practices and policies. However, this Recommendation can be used for telecommunication structures if agreed by the telecommunication operator. + +This Recommendation shall be used together with [ITU-T K.72], which provides the risk assessment against lightning flashes to the telecommunication line. Recommendation [ITU-T K.85] provides the risk assessment against equipment damage in customer premises. + +The protection need for line equipment (such as multiplexers, power amplifiers, optical network units) and line termination equipment is not considered in this Recommendation and it should be evaluated using the risk assessment applied to the structure where the equipment is located (i.e., exchange, customer's building, or remote electronic site). + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.21] Recommendation ITU-T K.21 (2011), *Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents*. +- [ITU-T K.60] Recommendation ITU-T K.60 (2008), *Emission levels and test methods for wireline telecommunication networks to minimize electromagnetic disturbance of radio services*. +- [ITU-T K.66] Recommendation ITU-T K.66 (2011), *Protection of customer premises from overvoltages*. +- [ITU-T K.71] Recommendation ITU-T K.71 (2011), *Protection of customer antenna installations*. +- [ITU-T K.72] Recommendation ITU-T K.72 (2011), *Protection of telecommunication lines using metallic conductors against lightning – Risk management*. + +- [ITU-T K.85] Recommendation ITU-T K.85 (2011), *Requirements for the mitigation of lightning effects on home networks installed in customer premises*. +- [IEC 62305-2] IEC 62305-2 (2010), *Protection against lightning – Part 2: Risk management*. +[http://webstore.iec.ch/webstore/webstore.nsf/ArtNum\\_PK/45856?OpenDocument](http://webstore.iec.ch/webstore/webstore.nsf/ArtNum_PK/45856?OpenDocument) +- [IEC 62305-3] IEC 62305-3 (2010), *Protection against lightning – Part 3: Physical damage to structures and life hazard*. +[http://webstore.iec.ch/webstore/webstore.nsf/ArtNum\\_PK/46595?OpenDocument](http://webstore.iec.ch/webstore/webstore.nsf/ArtNum_PK/46595?OpenDocument) +- [IEC 62305-4] IEC 62305-4 (2010), *Protection against lightning – Part 4: Electrical and electronic systems within structures*. +[http://webstore.iec.ch/webstore/webstore.nsf/ArtNum\\_PK/46590?OpenDocument](http://webstore.iec.ch/webstore/webstore.nsf/ArtNum_PK/46590?OpenDocument) + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following term defined elsewhere: + +**3.1.1 telecommunication network** [ITU-T K.60]: Entirety of equipment (comprising any combination of the following: network cable, telecommunication terminal equipment, and telecommunication system or installation) that is indispensable to ensure normal intended operation of the telecommunication network. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 dangerous event**: Lightning flash to or near the telecommunication line to be protected which causes a dangerous surge voltage due to lightning. + +**3.2.2 dangerous surge voltage due to lightning**: A surge voltage whose peak value $U_p$ is greater than the equipment resistibility or the conductor insulation surge voltage withstand level of the telecommunication line. + +**3.2.3 electronic system**: System incorporating sensitive electronic components such as communication equipment, computers, control and instrumentation systems, radio systems and power electronic installations. + +**3.2.4 failure of electrical and electronic systems**: Permanent damage of electrical and electronic systems due to surges. + +**3.2.5 lightning flash near a line**: Lightning flash striking close enough to a line to be protected that it may cause dangerous surges. + +**3.2.6 lightning flash to a structure connected to the line to be protected**: Lightning flash striking the structure connected to the line to be protected. + +**3.2.7 line to be protected**: Line connected to a structure for which protection is required against the effects of lightning in accordance with this Recommendation. + +**3.2.8 loss $L_x$** : Annual mean amount of loss (humans and goods) consequent to a specified type of damage due to a dangerous event, relative to the total value (humans and goods) of the object to be protected. + +**3.2.9 metallic symmetric conductors**: Transmission media consisting of a pair of twisted wires balanced with respect to earth, usually assembled in groups in order to form a telecommunication cable. + +**3.2.10 node:** Point between sections of a telecommunication line. + +NOTE – The list of nodes on a telecommunication installation is shown in the reference configuration (clause 5). + +**3.2.11 physical damage:** Damage to a telecommunication line due to mechanical and thermal effects of lightning. + +**3.2.12 priority service:** A priority service is a service where the loss of the telecommunication service may result in loss of life. + +**3.2.13 protection measures:** Measures to be adopted in the telecommunication installation to be protected to reduce the risk. + +**3.2.14 risk component $R_x$ :** Partial risk depending on the source and the type of damage. + +**3.2.15 risk $R$ :** Value of probable average annual loss (humans and goods) due to lightning, relative to the total value (humans and goods) of the object to be protected. + +**3.2.16 section of a telecommunication line $S_s$ :** Part of a telecommunication line with homogeneous characteristics where only one set of parameters is involved in the assessment of a risk component. + +**3.2.17 source of damage:** The source of damage depends on the position of the point of strike relative to the considered line: + +- Source of damage $S_1$ : Flashes to the structure (the exchange, the customer's building, or remote site) where the telecommunication or the signalling line enters. +- Source of damage $S_2$ : Flashes near the structure (the exchange, the customer's building, or remote site) where the telecommunication or the signalling line enters. +- Source of damage $S_3$ : Flashes to the telecommunication line entering the structure (the exchange, the customer's building, or remote site). +- Source of damage $S_4$ : Flashes near the telecommunication line entering the structure (the exchange, the customer's building, or remote site). + +**3.2.18 surge:** Temporary excessive voltage or current, or both, coupled on a telecommunication line from an external electrical source. + +NOTE 1 – Typical electrical sources are lightning and AC/DC power systems. + +NOTE 2 – Electrical source coupling can be one or more of the following: electric field (capacitive), magnetic field (inductive), conductive (resistive), electromagnetic field. + +**3.2.19 surge due to lightning:** A surge that is caused by lightning through any type of electromagnetic (conductive, inductive and capacitive) coupling. + +NOTE – It is characterized by the following five parameters: peak value; front time, $T_1$ ; time to half value, $T_2$ (or time parameters $T_1/T_2$ ); steepness; and specific energy. + +**3.2.20 surge protective device (SPD):** Device that restricts the voltage of a designated port or ports, caused by a surge, when it exceeds a predetermined level. + +- 1) Secondary functions may be incorporated, such as a current-limiting device to restrict a terminal current. +- 2) Typically, the protective circuit has at least one non-linear voltage-limiting surge protective component. +- 3) An SPD is a combination of a protection circuit and holder. + +**3.2.21 telecommunication installation:** A combination of equipment, systems, finished products and/or components assembled and/or erected by an assembler/installer at a given place to operate together in order to provide telecommunication services. + +**3.2.22 telecommunication line:** Transmission medium intended for communication between equipment that may be located in separate structures, such as a phone line and a data line. + +**3.2.23 tolerable risk $R_T$ :** Maximum value of the risk which can be tolerated for the object to be protected. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|----------|---------------------------------------------------| +| DSLAM | Digital Subscriber Line Access Multiplier | +| EB | Equipotential Bonding | +| EBB | Equipotential Bonding Bar | +| EPR | Earth Potential Rise | +| GDT | Gas Discharge Tube | +| LEMP | Lightning Electromagnetic Pulse | +| LPL | Lightning Protection Level | +| LPS | Lightning Protection System | +| MDF | Main Distribution Frame | +| MET | Main Earthing Terminal | +| MSPD | Multiservice Surge Protective Device | +| NT | Network Termination | +| PE | Protective Earthing | +| RCCB | Residual Current Circuit Breaker | +| RCD | Residual Current Device | +| SELV | Safety Extra Low Voltage | +| SPD | Surge Protective Device | +| CDMA WLL | Code Division Multiple Access Wireless Local Loop | + +# 5 Reference configuration + +The telecommunication network to be considered is the physical connection between: + +- the switch telecommunication building and the customer's building; or +- two switch telecommunication buildings; or +- two customer's buildings. + +The telecommunication network to be protected using this Recommendation is limited to telecommunication lines (buried or aerial cables, shielded or unshielded cables). + +Figure 1 shows the reference configurations for the telecommunication lines using metallic symmetric conductors, where the nodes and the cable sections between them can be seen. + +The nodes of Figure 1 have the following description: + +Node E: Entrance of the exchange building, e.g., main distribution frame (MDF). + +Node P: Transition between paper-insulated and plastic-insulated buried cables. + +Node C: Transition between buried and aerial cables. + +Node R: Entrance of remote electronic sites with active equipment, e.g., DSLAM. + +Node D: Transition between shielded and unshielded aerial cables. + +Node S: Entrance of the customer's building. + +![Figure 1 – Reference configuration diagram showing network connections between Exchange Buildings and Customer buildings.](ff0952ef692c9d960ce5f6708bcc9711_img.jpg) + +The diagram illustrates a network configuration. On the left, 'Exchange Building 1' contains two 'Eq.' (equipment) boxes connected to a central 'E' (equipment) box. 'Exchange Building 2' contains one 'Eq.' box connected to an 'E' box. A line connects the 'E' box in Exchange Building 2 to the main horizontal line. The main horizontal line consists of a sequence of nodes: 'P', 'C', 'D', 'R', 'P', 'C', 'D', and 'S'. The 'R' node is connected to the 'E' box in Exchange Building 1. The 'S' node is connected to two 'Customer buildings'. 'Customer building 1' contains two 'Eq.' boxes connected to the 'S' node. 'Customer building 2' contains one 'Eq.' box connected to its own 'S' node, which is also connected to the main horizontal line. A text label 'Eq. is equipment' is placed near the center of the diagram. + +Figure 1 – Reference configuration diagram showing network connections between Exchange Buildings and Customer buildings. + +**Figure 1 – Reference configuration** + +# **6 Explanation of terms** + +## **6.1 Damage and loss** + +### **6.1.1 Source of damage** + +The lightning current is the primary source of damage. + +In general, the following sources are distinguished by the strike attachment point (Figure 2): + +- S1: Flashes to a structure. +- S2: Flashes near a structure. +- S3: Flashes to a service (which includes a telecommunication line). +- S4: Flashes near a service (which includes a telecommunication line). + +| Source of damage | Striking point | +|------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| S1 | Diagram of a house with a lightning strike on the roof. | +| S3 | Diagram of a bridge with a lightning strike on the cables. | +| S2 | Diagram of a house with a lightning strike on the side wall. | +| S4 | Diagram of a bridge with a lightning strike on the support tower. | + +**Figure 2 – Lightning as source of damage** + +### 6.1.2 Types of damage to persons + +A lightning flash may cause injury depending upon the characteristics of the telecommunication network and the structure. Some of the most important characteristics are: + +- type of structure construction, e.g., timber, brick or reinforced concrete; +- type of telecommunication cable, e.g., shielded or unshielded; +- whether or not protection measures have been used at the structure or on the network cable. + +In general, for practical applications of the risk assessment, it is useful to distinguish between three basic types of damage which can appear as the consequence of lightning flashes. They are as follows. + +- D1: Injury to living beings by electric shock. +- D2: Physical damage (may cause a fire or gas explosion). +- D3: Failure of electrical and electronic systems (only where a person has a medical dependency on the telecommunication service). + +Lightning striking the telecommunication network can cause: + +- a step and touch potential between the equipment, connected to the telecommunication service, and the structure earth environment; +- a flashover within the structure causing a fire or a gas explosion; +- an outage of the telecommunication service due to damage to the physical line itself (both in the network or the structure) and to the telecommunication equipment (both in the network and in the structure). + +### 6.1.3 Types of loss + +Each type of damage, alone or in combination with others, may produce a different consequential loss in the object to be protected. The type of loss that may appear depends on the characteristics of the object to be protected. + +In general, the following types of loss shall be taken into account: + +L1: Loss of human life + +L2: Loss of service to the public + +L3: Loss of cultural heritage + +L4: Loss of economic value (structure and its contents, service and loss of activity) + +The type of loss considered in this Recommendation is: + +L1: Loss of human life + +This Recommendation will also consider the risk of injury. + +## **6.2 Risk and risk components** + +### **6.2.1 Risk** + +The risk $R$ is the value of a probable average annual loss. + +To evaluate risk, $R$ , the relevant risk components (partial risks depending on the source and type of damage) shall be defined and calculated. + +The risk, $R$ , is the sum of the risk components. + +The risk components, as defined in [IEC 62305-2], which can cause all types of loss, are listed in clauses 6.2.2 to 6.2.5. + +### **6.2.2 Risk components for a structure due to flashes to the structure** + +Direct lightning flashes to the structure to which the telecommunication network is connected can cause the following risk component: + +$R_A$ : Component related to injury to living beings caused by electric shock due to touch and step voltages inside the structure and in the zones up to 3 m outside the structure. Loss of type L1 and, in the case of structures holding livestock, loss of type L4 with possible loss of animals may also arise. + +NOTE – In special structures, people may be endangered by direct strikes (e.g., top level of garage parking or stadiums). These cases may also be considered using the principles of this standard. + +$R_B$ : Component related to physical damage caused by dangerous sparking inside the structure triggering fire or explosion, which may also endanger the environment. All types of loss (L1, L2, L3 and L4) may arise. + +$R_C$ : Component related to failure of internal systems caused by LEMP. Loss of type L2 and L4 could occur in all cases along with type L1 in the case of structures with risk of explosion and hospitals or other structures where failure of internal systems immediately endangers human life. + +### **6.2.3 Risk component for a structure due to flashes near the structure** + +$R_M$ : Component related to failure of internal systems caused by LEMP. Loss of type L2 and L4 could occur in all cases, along with type L1 in the case of structures with risk of explosion and hospitals or other structures where failure of internal systems immediately endangers human life. + +### 6.2.4 Risk components for a structure due to flashes to a line connected to the structure + +$R_U$ : Component related to injury to living beings caused by electric shock due to touch voltage inside the structure. Loss of type $L_1$ and, in the case of agricultural properties, losses of type $L_4$ with possible loss of animals could also occur. + +$R_V$ : Component related to physical damage (fire or explosion triggered by dangerous sparking between external installation and metallic parts generally at the entrance point of the line into the structure) due to lightning current transmitted through or along incoming lines. All types of loss ( $L_1$ , $L_2$ , $L_3$ , $L_4$ ) may occur. + +$R_W$ : Component related to failure of internal systems caused by overvoltages induced on incoming lines and transmitted to the structure. Loss of type $L_2$ and $L_4$ could occur in all cases, along with type $L_1$ in the case of structures with risk of explosion and hospitals or other structures where failure of internal systems immediately endangers human life. + +NOTE 1 – The lines taken into account in this assessment are only the lines entering the structure. + +NOTE 2 – Lightning flashes to or near pipes are not considered as a source of damage based on the bonding of pipes to an equipotential bonding bar. If an equipotential bonding bar is not provided, such a threat must also be considered. + +### 6.2.5 Risk component for a structure due to flashes near a line connected to the structure + +$R_Z$ : Component related to failure of internal systems caused by overvoltages induced on incoming lines and transmitted to the structure. Loss of type $L_2$ and $L_4$ could occur in all cases, along with type $L_1$ in the case of structures with risk of explosion and hospitals or other structures where failure of internal systems immediately endanger human life. + +NOTE 1 – The lines taken into account in this assessment are only the lines entering the structure. + +NOTE 2 – Lightning flashes to or near pipes are not considered as a source of damage based on the bonding of pipes to an equipotential bonding bar. If an equipotential bonding bar is not provided, such a threat must also be considered. + +## 6.3 Composition of risk components related to a structure + +Risk components to be considered for each type of loss in a structure are listed below: + +$R_1$ : Risk of loss of human life: + +$$R_1 = R_{A1} + R_{B1} + R_{C1}^{1)} + R_{M1}^{1)} + R_{U1} + R_{V1} + R_{W1}^{1)} + R_{Z1}^{1)}$$ + +1) Only for structures with risk of explosion and for hospitals with life-saving electrical equipment or other structures when failure of internal systems immediately endangers human life. + +The above formula determines the general risk $R_1$ for a person inside or outside the structure. The purpose of this Recommendation is to determine the risks of injury associated with the telecommunication service provided over metallic conductors. + +It should be understood that the metallic telecommunication service brings a remote earth into the structure. As well as the surges entering the structure from the telecommunication line a lightning strike to the structure or to the power service can cause a touch potential between the telecommunication remote earth and the structure earth. + +# 7 Risk management + +## 7.1 Basic procedure + +The following procedure shall be applied: + +- identification of the structure and the relevant services and their characteristics; +- identification of the risk components to be used, e.g., + - electric shock + - fire and explosion + - loss of service (priority services only); +- identification of sources of damage + - direct strikes to telecommunication service ( $S_3$ ) + - direct strikes to structure ( $S_1$ ) + - direct strikes to non telecommunication services ( $S_3$ ) + - indirect strikes to telecommunication service ( $S_4$ ); +- evaluation of risk $R_1$ ; +- evaluation of need of protection, by the comparison of the risk $R_1$ with the tolerable risk, $R_T$ . + +## 7.2 Tolerable risk $R_T$ + +It is the responsibility of the authority having jurisdiction to identify the value of tolerable risk. + +A representative value of tolerable risk, $R_T$ , against loss related to loss of human life or injuries due to lightning is given in Table 1. + +**Table 1 – Typical values of tolerable risk $R_T$** + +| Types of loss | $R_T(y^{-1})$ | +|------------------------------------------|---------------| +| Loss of human life or permanent injuries | $10^{-5}$ | + +## 7.3 Specific procedure to evaluate the need for protection + +### 7.3.1 Specific procedure to evaluate the need for protection by the telecommunication network operator + +For the risk due to lightning strikes to the telecommunication service, the following steps shall be taken: + +- identification of the relevant service and its characteristics; +- calculation of the product $N_{Ltelecom} \times P_{LD}$ ; +- calculation of need of protection, by the comparison of the product with the product limit (a product limit = 0.1 is recommended). + +The limit value of the telecommunication cable becomes $L_L = \frac{2500}{N_G \times C_E \times C_I \times P_{LD}}$ where $L_L$ is in metres. + +Figure 3 shows the flow chart to evaluate the protection need and for selecting the protection measures. + +### 7.3.2 Specific procedure to evaluate the need for protection by the structure owner + +For risk $R_1$ the following steps shall be taken: + +- identification of the structure and the relevant services and their characteristics; +- identification of the tolerable risk $R_T$ ; +- identification of the risk components to be used, e.g., + - electric shock + - fire and explosion + - loss of service (priority services only); +- identification of sources of damage + - direct strikes to structure ( $S_1$ ) + - direct strikes to telecommunication service ( $S_3$ ) + - direct strikes to non telecommunication services ( $S_3$ ) + - indirect strikes to telecommunication and power service ( $S_4$ ) (priority services only); +- calculation of risk $R_1$ using the relevant risk components, see Annexes A-C; +- calculation of need of protection, by the comparison of the risk $R_1$ with the tolerable risk, $R_T$ . + +Figure 4 shows the flow chart to evaluate the protection needs and for selecting the protection measures of telecommunication lines. + +## 7.4 Protection measures + +Protection measures are directed to reduce the risk according to the type of damage. + +Protection measures shall be considered effective only if they conform to the requirements of [ITU-T K.66], [IEC 62305-3] for structure/primary protection and [IEC 62305-4] for equipment protection. + +## 7.5 Selection of protection measures + +The selection of the most suitable protection measures shall be made by the protection designer according to the share of each risk component in the total risk and according to the technical and economic aspects of the different protection measures. + +Critical parameters shall be identified to determine the more efficient measure to reduce the risk $R_1$ . + +For each type of loss, there is a number of protection measures which, individually or in combination, make the condition $R_1 \leq R_T$ . The solution to be adopted shall be selected with allowance for technical and economic aspects. A simplified procedure for selection of protective measures is given in Figures 3 and 4. In any case, the installer or planner should identify the most critical risk components and reduce them, also taking into account economic aspects. Figure 3 is used by the telecommunication network operator to determine when to install a GDT at the point of entry of the telecommunication cable/line. Figure 4 is used to perform a full risk assessment. + +![Flowchart for determining GDT installation based on service delivery medium and risk factors.](9c6461e1e94afae4dec455e69a2ce152_img.jpg) + +``` + +graph TD + A["Identify +• the service delivery medium, e.g., copper, coaxial, optical fibre or wireless; +• all external telecommunication network cables."] --> B{Is it wireless?} + B -- Yes --> C["Refer to [ITU-T K.71]"] + B -- No --> D["Calculate $N_{Ltelecoms} \times P_{LDtelecoms}$ "] + D --> E{" $N_{Ltelecoms} \times P_{LDtelecoms} \Rightarrow 0.1$ "} + E -- No --> F["Telecommunication network operator has met his/her obligations"] + E -- Yes --> G["Install protective measures against direct flashes to external telecommunication cables, see clause 9 of [ITU-T K.66]."] + G --> F + +``` + +The flowchart outlines the procedure for a telecommunication operator to determine when to install a GDT at the point of entry of the telecommunication cable/line. It begins with identifying the service delivery medium (copper, coaxial, optical fibre, or wireless) and all external telecommunication network cables. A decision point asks if it is wireless. If yes, the operator refers to [ITU-T K.71]. If no, the operator calculates the product of $N_{Ltelecoms}$ and $P_{LDtelecoms}$ . Another decision point checks if this product is greater than or equal to 0.1. If no, the operator has met their obligations. If yes, protective measures against direct flashes to external telecommunication cables (as per clause 9 of [ITU-T K.66]) must be installed, after which the operator has met their obligations. + +Flowchart for determining GDT installation based on service delivery medium and risk factors. + +**Figure 3 – Procedure for telecommunication operator to determine when to install a GDT at the point of entry of the telecommunication cable/line** + +![Flowchart for building owner selecting protection measures for the structure. The process starts with identifying the structure, tolerable risk, service delivery medium, and external cables. It then checks if it's wireless. If yes, refer to ITU-T K.71. If no, calculate risk components (RA, RB, RU, RV). Then it checks if RI ≥ RT. If yes, install protective measures against direct flashes to external cables (ITU-T K.66). If no, it checks again if RI ≥ RT. If yes, install protective measures against direct flashes to structure (IEC 62305-3). If no, users within the structure are protected. A note indicates this recommendation only considers direct strikes and refers to ITU-T K.85 for equipment damage risk.](b6671cfafda3820aafe9a24fa7a4d8c7_img.jpg) + +``` + +graph TD + A["Identify +• the structure to be protected; +• the tolerable risk $R_T$ ; +• the service delivery medium, e.g., +copper, coaxial, optical fibre or wireless; +• all external cables including customer +cables."] --> B{Is it wireless?} + B -- Yes --> C["Refer to [ITU-T K.71]"] + B -- No --> D["Calculate the risk components + $R_I = R_A, R_B, R_U$ and $R_V$ "] + D --> E{" $R_I \geq R_T$ ?"} + E -- Yes --> F["Install protective measures +against direct flashes to +external cables, see clause 9 +of [ITU-T K.66]."] + E -- No --> G{" $R_I \geq R_T$ ?"} + G -- Yes --> H["Install protective measures +against direct flashes to +structure; see +[IEC 62305-3]"] + G -- No --> I["Users within the structure +are protected"] + F --> I + H --> I + J["This Recommendation only considers direct +strikes. Refer to [ITU-T K.85] to calculate the +risk of damage to equipment for priority +services."] -.-> I + +``` + +Flowchart for building owner selecting protection measures for the structure. The process starts with identifying the structure, tolerable risk, service delivery medium, and external cables. It then checks if it's wireless. If yes, refer to ITU-T K.71. If no, calculate risk components (RA, RB, RU, RV). Then it checks if RI ≥ RT. If yes, install protective measures against direct flashes to external cables (ITU-T K.66). If no, it checks again if RI ≥ RT. If yes, install protective measures against direct flashes to structure (IEC 62305-3). If no, users within the structure are protected. A note indicates this recommendation only considers direct strikes and refers to ITU-T K.85 for equipment damage risk. + +**Figure 4 – Procedure for building owner selecting protection measures for the structure** + +# 8 Responsibility + +It is recommended that responsibility of protection measures be shared, as shown in Table 2. + +**Table 2 – Responsibility of protection measures** + +| Function | Responsibility | +|-------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Installation of an LPS |
  • Building owner
| +| Installation of an effective earthing and bonding system, including the required EBB |
  • Building owner
| +| Manufacture of equipment with a minimum level of resistibility to the relevant standard (e.g., basic level of [ITU-T K.21] for telecommunication equipment) |
  • Manufacturer
| +| Use of equipment with the required level of resistibility to the relevant standard |
  • Network equipment: network operator
  • Customer equipment: customer/regulator
| +| Structure risk analysis associated with the telecommunication installation |
  • Network operator/Service owner. It is recommended, as a minimum, that the network operator/service owner calculate the product of the number of direct flashes to the telecommunication line and P_{LD}.
| +| Total structure risk analysis |
  • Building owner
| +| Installation of SPDs and bonding of metallic pipes and cable screens |
  • Installation of services SPDs to protect the network (including network equipment within the structure), bonding of cable screens and metallic pipes in the public network: network operator/service owners.
  • Installation of telecommunication service SPDs to reduce the risk of injury to persons using the telecommunication service: telecommunication network operator/service owner when N_{Ltelecoms} \times P_{LDtelecoms} \geq 0.1. The limit value L_L (in metres) of the telecommunication cable becomes L_L = \frac{2500}{N_G \times C_E \times C_I \times P_{LD}}
  • Installation of customer SPDs to prevent injury of occupants within the structure and to protect the structure and its contents, bonding of cable screens and metallic pipes in the private network: building owner.
| +| Customer owned equipment risk analysis and installation of equipment protection, e.g., MSPD |
  • Equipment owner
| + +# Annex A + +## Assessment of annual number $N$ of dangerous events + +(This annex forms an integral part of this Recommendation.) + +Annex A of [IEC 62305-2] provides the formulas required to calculate the average numbers of strikes influencing structures, aerial lines and underground cables per annum. + +### A.1 Assessment of the average annual number of dangerous events $N_L$ due to flashes to a line + +Edition 2 of [IEC 62305-2] calculates $N_L$ using factor $C_E$ while [b-IEC 62305-2 Ed.1] used factor $C_D$ . Factor $C_D$ includes a factor of 2 for objects on a hilltop or knoll. Factor $C_E$ does not have this factor of 2, as it is a factor originally related the shielding of electromagnetic waves by buildings. Telecommunication network operator experience has shown that cables installed on a hill or along a ridge have a much higher exposure to direct strikes than cables installed on flat ground. To take this higher exposure into account, when considering direct strikes to an aerial or underground cable installed on a hill or along a ridge, a factor of 2 is recommended. It is recommended that the amended factor for $C_E$ given in Table A.1 be used. + +**Table A.1 – Modified [IEC 62305-2] Table A.4 – Line environmental factor $C_E$** + +| Environment | $C_E$ | +|---------------------------------------------------------|-------| +| Lines installed on a hill in a rural area a) | 2 | +| Rural | 1 | +| Suburban | 0.5 | +| Urban | 0.1 | +| Urban with tall buildings b) | 0.01 | + +a) Experience shows that telecommunication lines installed on a hill in a rural area are more likely to be subjected to a direct strike than lines installed on flat ground. Lines installed along a ridge in a rural area are a particular problem. +b) Buildings higher than 20 m. + +The value of the line length $L_L$ used is critical to obtaining a reasonable answer. The actual length of the line can vary from literally tens of m to tens of km. The start of the cable is the closest earthed equipment and the end of the cable is the structure. + +# Annex B + +## Assessment of probability $P_x$ of damage for a structure + +(This annex forms an integral part of this Recommendation.) + +Annex B of [IEC 62305-2] provides the formulas required to calculate the probability that a lightning strike will cause a loss, e.g., injury. This Recommendation only considers direct strikes. Refer to [ITU-T K.85] to calculate the risk of damage to equipment for priority services. A priority service is a service where the loss of the telecommunication service may result in loss of life. + +### B.1 Probability $P_A$ + +Probability $P_A$ according to [IEC 62305-2] can be used to determine the risk of injury taking into account the installation of SPDs. + +$P_A$ is equal to $P_{TA} \times P_B$ + +### B.2 Probability $P_B$ + +IEC uses $P_B$ to calculate the probability of injury related to physical damage caused by dangerous sparking inside the structure triggering a fire or explosion. This value of $P_B$ is given in Table B.2 of [IEC 62305-2]. + +### B.3 Probability $P_C$ + +According to [IEC 62305-2] probability $P_C$ is only used if the life of the building occupant is dependent upon the telecommunication service. This is not considered in this version of ITU-T K.89. Refer to [ITU-T K.85] to calculate the risk of damage to equipment for priority services. + +$P_C$ is equal to $P_{SPD} \times C_{LD}$ + +### B.4 Probability $P_M$ + +According to [IEC 62305-2] probability $P_M$ is only used if the life of the building occupant is dependent upon the telecommunication service. This is not considered in this version of ITU-T K.89. Refer to [ITU-T K.85] to calculate the risk of damage to equipment for priority services. + +$P_M$ is equal to $P_{SPD} \times P_{MS}$ + +### B.5 Probability $P_U$ + +The values of probability $P_U$ of injury to living beings inside the structure due to touch voltage by a flash to a line entering the structure depends on the characteristics of the line shield, the impulse withstand voltage of internal systems connected to the line, the protection measures like physical restrictions or warning notices and the isolating interfaces or SPD(s) provided for equipotential bonding at the entrance of the line according to [IEC 62305-3] or [ITU-T K.66]. + +NOTE 1 – A coordinated SPD system according to [IEC 62305-4] is not necessary to reduce $P_U$ ; in this case SPD(s) according to [IEC 62305-3] are sufficient, i.e., it is only necessary to install primary protection on the incoming services. + +$P_U$ is equal to $P_{TU} \times P_{EB} \times P_{LD} \times C_{LD}$ + +where: + +$P_{TU}$ depends on protection measures against touch voltages, such as physical restrictions or warning notices. Values of $P_{TU}$ are given in Table B.6 of [IEC 62305-2]. + +$P_{EB}$ depends on lightning equipotential bonding (EB) conforming to [IEC 62305-3] and on the lightning protection level (LPL) for which its SPDs are designed. Values of $P_{EB}$ are given in Table B.7 of [IEC 62305-2]. + +$P_{LD}$ is the probability of failure of internal systems due to a flash to the connected line depending on the line characteristics. Values of $P_{LD}$ are given in Table B.8 of [IEC 62305-2]. In this case, $U_W$ is used to determine the probability of a flashover between the telecommunication line and the power line, with the user of the equipment. + +$C_{LD}$ is a factor depending on shielding, earthing and isolation conditions of the line. Values of $C_{LD}$ are given in Table B.4 of [IEC 62305-2]. + +NOTE 2 – When SPD(s) according to [IEC 62305-3] are provided for equipotential bonding at the entrance of the line, earthing and bonding according to [IEC 62305-4] may improve protection. + +### B.6 Probability $P_V$ + +The values of probability $P_V$ of physical damage by a flash to a line entering the structure depend on the characteristics of the line shield, the impulse withstand voltage of internal systems connected to the line and the isolating interfaces or the SPDs provided for equipotential bonding at the entrance of the line according to [IEC 62305-3]. + +NOTE – A coordinated SPD system according to [IEC 62305-4] is not necessary to reduce $P_V$ ; in this case, SPDs according to [IEC 62305-3] are sufficient. + +$P_V$ is equal to $P_{EB} \times P_{LD} \times C_{LD}$ + +where: + +$P_{EB}$ depends on lightning equipotential bonding (EB) conforming to [IEC 62305-3] and on the lightning protection level (LPL) for which its SPDs are designed. Values of $P_{EB}$ are given in Table B.7 of [IEC 62305-2]. + +$P_{LD}$ is the probability of failure of internal systems due to a flash to the connected line depending on the line characteristics. Values of $P_{LD}$ are given in Table B.8 of [IEC 62305-2]. In this case, $U_W$ is used to determine the probability of a flashover between the telecommunication line and the power line, with the user of the equipment. + +$C_{LD}$ is a factor depending on shielding, earthing and isolation conditions of the line. Values of $C_{LD}$ are given in Table B.4 of [IEC 62305-2]. + +### B.7 Probability $P_W$ + +According to [IEC 62305-2] probability $P_W$ is only used if the life of the building occupant is dependent upon the telecommunication service. This is not considered in this version of this Recommendation. Refer to [ITU-T K.85] to calculate the risk of damage to equipment for priority services. + +$P_W$ is equal to $P_{SPD} \times P_{LD} \times C_{LD}$ + +### B.8 Probability $P_Z$ + +According to [IEC 62305-2] probability $P_Z$ is only used if the life of the building occupant is dependent upon the telecommunication service. This is not considered in this version of this Recommendation. Refer to [ITU-T K.85] to calculate the risk of damage to equipment for priority services. + +$P_Z$ is equal to $P_{SPD} \times P_{LI} \times C_{LI}$ + +# Annex C + +## Assessment of amount of loss $L_X$ in a structure + +(This annex forms an integral part of this Recommendation.) + +Edition 2 of [IEC 62305-2] has the following loss calculations for loss of life due to damage D1, see clause 6.1.2. + +$$L_A = r_t \times L_T \times n_z/n_t \times t_z/8760$$ + +$$L_B = r_p \times r_f \times h_z \times L_F \times n_z/n_t \times t_z/8760$$ + +$$L_U = r_t \times L_T \times n_z/n_t \times t_z/8760$$ + +$$L_V = r_p \times r_f \times h_z \times L_F \times n_z/n_t \times t_z/8760$$ + +# Appendix I + +## Example of a risk assessment according to [IEC 62305-2] + +(This appendix does not form an integral part of this Recommendation.) + +### I.1 General + +The structure to be considered is a customer building in a rural area with a power line and a telecommunication line. The tables below follow the risk assessment example in [IEC 62305-2] and may not include all mechanisms of damage. + +The following clauses report the results of the risk assessment to the structure in accordance with [IEC 62305-2] and the possible protection measures in order to reduce the risks below the tolerable values. An understanding of [IEC 62305-2] is required to understand this Appendix. + +### I.2 Building characteristics + +The main building characteristics are reported in Table I.1. + +**Table I.1 – Building characteristics** + +| Parameter | Comment | Symbol | Value | Reference (Note) | +|----------------------------------|-------------------------|-----------------------------|-------------------------------|------------------| +| Dimensions (m) | | $(L_b \cdot W_b \cdot H_b)$ | $20.0 \times 15.0 \times 6.0$ | | +| Location factor | Isolated | $C_{db}$ | 1.0 | Table A.1 | +| Probability $P_A$ | | $P_A$ | 1.0 | Equation B.1 | +| Additional protection measures | None | $P_{TA}$ | 1.0 | Table B.1 | +| Characteristics of structure | None | $P_B$ | 1.0 | Equation B.2 | +| Shield at the structure boundary | None | $K_{S1}$ | 1.0 | Equation B.5 | +| Shield internal to the structure | None | $K_{S2}$ | 1.0 | Equation B.6 | +| Ground flash density | 1/km 2 /year | $N_g$ | 4.0 | | + +NOTE – Table and equation references are to [IEC 62305-2], unless otherwise stated. + +### I.3 Characteristics of the services + +There are two metallic services entering the building: + +- an aerial unshielded low voltage power line; +- an underground unshielded telecommunication line. + +The characteristics of the power line entering the structure are reported in Table I.2 together with the calculated values of the collection areas ( $A_l$ and $A_i$ ) and the expected dangerous events ( $N_L$ and $N_i$ ). + +**Table I.2 – Characteristics of the power line** + +| Parameter | Comment | Symbol | Value | Reference (Note) | +|--------------------------------------------------------------|------------|-----------------------------|-------|------------------| +| Soil resistivity (Wm) | | $\rho$ | 400 | | +| Length (m) | See Note 2 | $L_L$ | 200 | | +| Height (m) | | $H_c$ | 6 | | +| Line installation factor | Aerial | $C_I$ | 1.0 | Table A.2 | +| Line type factor | See Note 2 | $C_T$ | – | Table A.3 | +| Line environmental factor | Rural | $C_E$ | 1.0 | Table A.4 | +| Shield resistance per unit length ( $\Omega/\text{km}$ ) | Unshielded | | | | +| Probability $P_C$ | None | $P_C$ | 1.0 | Equation B.3 | +| Probability $P_{SPD}$ | None | $P_{SPD}$ | 1.0 | Table B.3 | +| Number of conductors entering the structure | | $m$ | 2 | | +| Collection area for lightning to the line ( $\text{m}^2$ ) | | $A_L$ | 8 000 | Equation A.9 | +| Number of direct lightning strikes to the line | | $N_L$ | 0.032 | Equation A.8 | +| Dimensions of the adjacent structure (m) | None | $(L_a \cdot W_a \cdot H_a)$ | | | +| Number of direct lightning strikes to the adjacent structure | | $N_{Da}$ | 0.0 | | + +NOTE 1 – Table references are to [IEC 62305-2] unless otherwise specified. + +NOTE 2 – The power line consists of 100 m between a single phase transformer and the structure. There is 500 m of HV line to another single phase transformer. Therefore $L_L = 100 + 0.2 \times 500 = 200 \text{ m}$ . + +The characteristics of the telecommunication line entering the structure are reported in Table I.3 together with the calculated values of the collection areas ( $A_l$ and $A_i$ ) and the expected dangerous events ( $N_L$ and $N_i$ ). + +**Table I.3 – Characteristics of the telecommunication line** + +| Parameter | Comment | Symbol | Value | Reference (Note) | +|------------------------------------------------------------|-------------|-----------|--------|------------------| +| Soil resistivity (Wm) | | $\rho$ | 400 | | +| Length (m) | | $L_L$ | 5 000 | | +| Conductor diameter | | $mm$ | 0.64 | | +| Line installation factor | Underground | $C_I$ | 0.5 | Table A.2 | +| Line type factor | No | $C_T$ | 1.0 | Table A.3 | +| Line environmental factor | Rural | $C_E$ | 1 | Table A.4 | +| Shield resistance per unit length ( $\Omega/\text{km}$ ) | Unshielded | | | | +| Probability $P_C$ | None | $P_C$ | 1.0 | Equation B.3 | +| Probability $P_{SPD}$ | None | $P_{SPD}$ | 1.0 | Table B.3 | +| Number of conductors entering the structure | | $m$ | 4 | | +| Collection area for lightning to the line ( $\text{m}^2$ ) | | $A_L$ | 80 000 | Equation A.9 | +| Number of direct lightning strikes to the line | | $N_L$ | 0.4 | Equation A.8 | + +**Table I.3 – Characteristics of the telecommunication line** + +| Parameter | Comment | Symbol | Value | Reference (Note) | +|-----------------------------------------------------------------------|---------|-----------------------------|-------|------------------| +| Dimensions of the adjacent structure (m) | None | $(L_a \cdot W_a \cdot H_a)$ | | | +| Number of direct lightning strikes to the adjacent structure | | $N_{Da}$ | 0.0 | | +| NOTE – Table references are to [IEC 62305-2] unless otherwise stated. | | | | | + +### I.4 Characteristics of the internal systems + +The main characteristics of the internal systems connected to the power line and telecommunication line are reported in Table I.4. + +**Table I.4 – Main characteristics of the internal installations** + +| Parameter | Comment | Symbol | Value | Reference (Note) | +|-------------------------------------------------------------|---------------|-----------|-------|------------------| +| Power service port | | | | | +| Shield resistance per unit length ( $\Omega/\text{km}$ ) | Unshielded | | | Table B.8 | +| Withstand voltage of the equipment | 2.5 kV | $K_{S4}$ | 0.4 | Equation B.7 | +| Installed coordinated SPD protection | Not installed | $P_{SPD}$ | 1 | Table B.3 | +| Probability factor due to direct lightning to the structure | | $C_{LD}$ | 1.0 | Table B.4 | +| Probability factor due to direct lightning near structure | | $C_{LI}$ | 1.0 | Table B.4 | +| Probability factor due to direct lightning to the line | | $P_{LD}$ | 1.0 | Table B.8 | +| Probability factor due to lightning near the line | | $P_{LI}$ | 0.3 | Table B.9 | +| Probability factor due to strike to structure | | $P_C$ | 1.0 | Equation B.2 | +| Probability factor due to a strike to the line | | $P_W$ | 1.0 | Equation B.10 | +| Probability factor due to a strike near to the line | | $P_Z$ | 0.3 | Equation B.11 | +| Telecommunication service port | | | | | +| Shield resistance per unit length ( $\Omega/\text{km}$ ) | Unshielded | | | Table B.8 | +| Withstand voltage of the equipment | 1.5 kV | $K_{S4}$ | 0.667 | Equation B.7 | +| Installed coordinated SPD protection | Not installed | $P_{SPD}$ | 1 | Table B.3 | +| Factor $C_{LD}$ | | $C_{LD}$ | 1.0 | Table B.4 | +| Probability factor due to direct lightning near structure | | $C_{LI}$ | 1.0 | Table B.4 | + +**Table I.4 – Main characteristics of the internal installations** + +| Parameter | Comment | Symbol | Value | Reference (Note) | +|------------------------------------------------------------------------------------|---------|----------|-------|------------------| +| Probability factor due to direct lightning to the line | | $P_{LD}$ | 1.0 | Table B.8 | +| Probability factor due to lightning near the line | | $P_{LI}$ | 0.5 | Table B.9 | +| Probability factor due to strike to structure | | $P^C$ | 1.0 | Equation B.2 | +| Probability factor due to a strike to the line | | $P_W$ | 1.0 | Equation B.10 | +| Probability factor due to a strike near to the line | | $P_Z$ | 0.5 | Equation B.11 | +| NOTE – Table and equation references are to [IEC 62305-2] unless otherwise stated. | | | | | + +### I.5 Zones definition in the structure + +The following main zones may be defined: + +- $Z_1$ (outside the building); +- $Z_2$ (inside the building). + +For zone $Z_1$ it is assumed that no people are outside the building. Therefore the risk of shock of people $R_A = 0$ . Because $R_A$ is the only risk component outside the building, zone $Z_1$ can be disregarded completely. + +Inside the building only one zone $Z_2$ is defined taking into account that: + +- both internal systems (power and telecom) extend throughout the building; +- no spatial shields exist; +- losses are assumed to be constant throughout the building. + +The resulting factors valid for zone $Z_2$ are reported in Table I.5. + +**Table I.5 – Characteristics of $Z_2$ (inside the building)** + +| Parameter | Comment | Symbol | Value | Reference (Note 1) | +|-----------------------------------------------|---------------------------------|----------|-----------------------|--------------------| +| Type of floor | Concrete | $r_t$ | $10^{-2}$
(Note 2) | Table C.3 | +| Protection against shock (flash to structure) | None | $P_{TA}$ | 1 | Table B.1 | +| Protection against shock (flash to line) | None | $P_{TU}$ | 1 | Table B.6 | +| Risk of fire | Low | $r_f$ | 0.001 | Table C.5 | +| Protection against fire | None | $r_p$ | 1.0 | Table C.4 | +| Special hazard | None | $h_z$ | 1.0 | Table C.6 | +| Loss due to electric shock (D1) | Due to touch and step potential | $L_T$ | 0.01 | Table C.2 | + +**Table I.5 – Characteristics of $Z_2$ (inside the building)** + +| Parameter | Comment | Symbol | Value | Reference (Note 1) | +|----------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|--------------------|--------------------| +| Loss due to physical damage (D2) | Others | $L_F$ | 0.01
(Note 3) | Table C.2 | +| Loss due to failure of internal system | N/A | $L_O$ | N/A | Table C.2 | +| Factor for person in zone | Number of persons in the zone | $n_z$ | 1 | Section C.3 | +| | Number of persons in the structure | $n_t$ | 1 | Section C.3 | +| | Time in hours per year exposed to risk | | 8760 | Section C.3 | +| | Resulting parameters | $L_A$ | $1 \times 10^{-4}$ | Equation C.1 | +| | | $L_B$ | $1 \times 10^{-5}$ | Equation C.3 | +| | | $L_U$ | $1 \times 10^{-4}$ | Equation C.2 | +| | | $L_V$ | $1 \times 10^{-5}$ | Equation C.3 | +| | NOTE 1 – Table and equation references are to [IEC 62305-2] unless otherwise stated.
NOTE 2 – The country house example in section E.2 of [IEC 62305-2] uses an $r_t$ value of $10^{-5}$ .
NOTE 3 – The country house example in section E.2 of [IEC 62305-2] uses an $L_f$ value of 0.1. | | | | + +### I.6 Expected dangerous events to the structure + +The number of expected dangerous events for the building is reported in Table I.6. + +**Table I.6 – Expected number of dangerous events** + +| Parameter | Comment | Symbol | Value | Reference (Note) | +|------------------------------------------------------------------------|---------|--------|--------|------------------| +| Collection area for structure ( $m^2$ ) | | $A_D$ | 2577 | Equation A.2 | +| Number of direct lightning strikes to the structure | | $N_D$ | 0.0103 | Equation A.4 | +| NOTE – Clause references are to [IEC 62305-2] unless otherwise stated. | | | | | + +### I.7 Risk assessment for the unprotected structure + +#### I.7.1 Risk assessment of injury (related to $R_1$ ) + +The values of the probability factors $P$ are reported in Table I.7. + +**Table I.7 – Risk $R_1$ : values of the probability factors** + +| Probability | Value | +|----------------------------|-------| +| $P_A$ | 1.0 | +| $P_B$ | 1.0 | +| $P_U$ (power) | 1.0 | +| $P_V$ (power) | 1.0 | +| $P_U$ (telecommunications) | 1.0 | +| $P_V$ (telecommunications) | 1.0 | + +The risk of injury can be calculated as follows: + +$$\text{Risk of injury} = R_A + R_B + R_U + R_V$$ + +The values of the risk components related to the building are reported in Table I.8. + +**Table I.8 – Risk $R_1$ : values of risk components** + +| Risk components | Risk | +|----------------------------------------------------------|-----------------------| +| $R_A = N_D \times P_A \times L_A$ | $1.03 \times 10^{-6}$ | +| $R_B = N_D \times P_B \times L_B$ | $1.03 \times 10^{-7}$ | +| $R_U$ (power) $= N_L \times P_U \times L_U$ | $3.2 \times 10^{-6}$ | +| $R_V$ (power) $= N_L \times P_V \times L_V$ | $3.2 \times 10^{-7}$ | +| $R_U$ (telecommunications) $= N_L \times P_U \times L_U$ | $4.00 \times 10^{-5}$ | +| $R_V$ (telecommunications) $= N_L \times P_V \times L_V$ | $4.00 \times 10^{-6}$ | +| TOTAL | $4.87 \times 10^{-5}$ | + +The risk $R_1$ is greater than the tolerable value of $10^{-5}$ . Therefore, protection measures are necessary. + +### I.8 Selected protection measures + +The main component of the risk is a lightning flash to the two services. Installing SPDs on the two services will significantly reduce the risk. + +### I.9 Risk assessment related to the protected structure + +#### I.9.1 Assessment of the risk of injury $R_1$ + +The values of the relevant probability factors $P$ are reported in Table I.9. + +**Table I.9 – Risk $R_1$ : values of the probability factors +(protected structure)** + +| Probability | Value | +|----------------------------|-------| +| $P_A$ | 1.0 | +| $P_B$ | 1.0 | +| $P_U$ (power) | 0.05 | +| $P_V$ (power) | 0.05 | +| $P_U$ (telecommunications) | 0.01 | +| $P_V$ (telecommunications) | 0.01 | + +The values of the risk components related to the protected building are reported in Table I.10. + +**Table I.10 – Risk $R_1$ : values of the risk components +(protected structure)** + +| Risk components | Risk | +|----------------------------------------------------------|-----------------------| +| $R_A = N_D \times P_A \times L_A$ | $1.03 \times 10^{-6}$ | +| $R_B = N_D \times P_B \times L_B$ | $1.03 \times 10^{-7}$ | +| $R_U$ (power) $= N_L \times P_U \times L_U$ | $1.60 \times 10^{-7}$ | +| $R_V$ (power) $= N_L \times P_V \times L_V$ | $1.60 \times 10^{-8}$ | +| $R_U$ (telecommunications) $= N_L \times P_U \times L_U$ | $4.00 \times 10^{-7}$ | +| $R_V$ (telecommunications) $= N_L \times P_V \times L_V$ | $4.00 \times 10^{-8}$ | +| TOTAL | $1.75 \times 10^{-6}$ | + +The selected protection measures reduce the risk of injury to less than the tolerable risk. + +### I.10 SPDs + +#### I.10.1 Selection of SPDs + +The selection of SPDs has to take into account the expected overcurrent values in the installation point as indicated in [b-ITU-T K.67] for telecommunication cables and [b-IEC 62305-1] for power cables. + +[b-ITU-T K.67] states, for a direct strike to a telecommunication cable: + +If the telecommunication or signalling line is unscreened or is not routed in metal conduit, each of the $m$ conductors of the line carries an equal part ( $I_f$ ) of the peak lightning current which may be evaluated by: + +$$I_f = \frac{0.25 \times I_p}{n \times m} \text{ kA for an unshielded line}$$ + +where $n = 1$ or $2$ ; the latter case applies for example, where telecommunication and power lines are close to each other, e.g., they share the same poles. + +The $I_f$ value given by the equation above shall be equal to or lower than the following value: + +$$I_f \leq 8 \times A \text{ kA}$$ + +where $A$ is the cross-sectional area of the telecommunication or signalling conductor [ $\text{mm}^2$ ]. + +Therefore, for $I_p = 200 \text{ kA}$ , $n = 1$ (number of cables) and $m = 4$ (number of conductors), + +$I_f = 12.5 \text{ kA}$ . However, the telecommunication cable conductor diameter is $0.64 \text{ mm}$ and therefore $I_f$ is a maximum of $2.57 \text{ kA}$ 10/350 independent of the LPL Class. + +[b-ITU-T K.12] Table 5 requires a Class 3 GDT to withstand a $2.5 \text{ kA}$ 10/350 surge current. Therefore, a Class 3 GDT would be suitable for use as point of entry protection on the telecommunication cable. According to [b-IEC 62305-1] Table E.3 this is an LPL Class I protection, i.e., $P_{\text{EB}} = 0.01$ . + +[b-IEC 62305-1] Table E.2 lists the expected current level on the mains conductors for LPL Class III – IV as $5 \text{ kA}$ 10/350. Therefore installing a $5 \text{ kA}$ 10/350 rated SPD at point of entry on the mains gives a protection level of LPL Class III – IV with a corresponding $P_{\text{EB}}$ of 0.05. + +# Appendix II + +## Equipotential bonding + +(This appendix does not form an integral part of this Recommendation.) + +### II.1 Non-conductive floors + +To prevent potential differences due to lightning strikes occurring within a structure, it is generally necessary to bond the service screens, service SPDs and conductive parts of the structure, e.g., metallic window frames and concrete floors, etc. to the MEB. Where the structure has a non-conductive floor it is necessary to consider the necessity of installing a ring earth, see Figure II.1. + +Figure 9.2-4 of [ITU-T K.66] shows the use of a buried ring earth to alleviate the problem with long bonding conductors. A use of a buried ring earth also reduces the potential differences between the MEB and the location of the telecommunication equipment user. + +![Diagram illustrating problems associated with non-conductive floors during a lightning strike.](a1890b9a9b85f13e67ed59bbad623659_img.jpg) + +The diagram illustrates the electrical and potential issues in a building with a non-conductive floor during a lightning strike. A lightning bolt strikes the ground near the building. Inside, an 'Electrical switchboard' and 'Telecommunications protection' unit are shown. A person is touching a piece of equipment connected to the telecommunications protection. A red line labeled 'Bonding between telecommunications and power' connects the two protection units. Below the building, a graph shows the 'Profile of earth potential with respect to remote earth', featuring a 'Voltage plateau due to arcing in the ground'. The vertical distance between the plateau and the remote earth level is labeled 'V', which is defined as 'the voltage between the earth electrode and the telecommunication users feet'. + +Diagram illustrating problems associated with non-conductive floors during a lightning strike. + +Figure II.1 – Problems associated with non-conductive floors + +### II.2 Lack of bonding between the telecommunication service, power service and the MEB + +The only way to ensure safety in a building is to provide equipotential bonding between the services, the MEB and all touchable metallic parts of the structure. Where it is not possible to directly bond the telecommunication and mains power bonding bars, consideration should be given to using a suitably rated SPD (current and clamping voltage) to provide equipotential bonding under lightning surge conditions but not under power frequency earth potential rise conditions. Where an SPD with a relatively high clamping voltage is used (to prevent conduction during power frequency earth potential rise conditions) it will be necessary to ensure that the equipment has appropriate resistibility and safety requirements. + +# **Appendix III** + +## **Cable routing** + +(This appendix does not form an integral part of this Recommendation.) + +There is a possible issue with potential differences in multi-storied buildings during a lightning strike to the building. [b-IEC 60364-4-44] shows that it may be necessary to route cables in such a way as to minimize coupling into the loop formed by the telecommunication/data and power cables. It may also be necessary to bond the PE conductor and the building CBN at floor level. Bonding in this way will prevent potential differences between the building steel and the PE conductor at floor level and hence the mains and telecommunication/data conductors with respect to the building steel at floor level. Either the equipment protection or breakdown of the equipment insulation will minimize potential differences. Compliance with [b-IEC 62364-4-44] is recommended. + +# Appendix IV + +## Risk assessment using Recommendation ITU-T K.47 + +(This appendix does not form an integral part of this Recommendation.) + +### IV.1 Assessment of annual number N of dangerous events + +[b-IEC 62305-2 Ed.1] calculates $A_L$ , for an underground cable, using formula containing Rho (resistivity). In [IEC 62305-2] $A_L$ is calculated assuming the resistivity is 400 ohm. Also, the calculation in [b-IEC 62305-2 Ed.1] is simplified compared with [b-ITU-T K.47]. The three formulas, assuming $\rho = 400 \Omega \cdot m$ , are listed below. + +[b-IEC 62305-2 Ed.1] $A_L = L_L \times 6 \times H$ for aerial cables. When $H = 6$ , $A_L = 36$ . + +$$A_L = L_L \times \sqrt{\rho} = L_L \times 20 \text{ for underground cables}$$ + +[IEC 62305-2] $A_L = C_I \times L_L \times 40$ for both aerial and underground cables + +where $C_I = 1$ for aerial cables and 0.5 for underground cables, which is a similar result to [b-IEC 62305-2 Ed.1]. + +[b-ITU-T K.47] $A_L = 2 \times L_L \times 3 \times H$ for aerial cables. This is similar to both editions of [IEC 62305-2] + +$$A_L = L_L \times 2 \times (2.91 + 0.191 \times \sqrt{\rho}) = L_L \times 13.46 \text{ for underground cables when } \rho = 400 \Omega \cdot m.$$ + +It is possible to calculate $A_L$ , for telecommunication and power cables, using [b-ITU-T K.47] as allowed by [IEC 62305-2]. This means that the calculated number of injuries will be less than that calculated using [b-IEC 62305-2 Ed.1] and [IEC 62305-2]. + +[IEC 62305-2] calculates $N_L$ using factor $C_E$ while [b-IEC 62305-2 Ed.1] used factor $C_D$ . Factor $C_D$ includes a factor of 2 for objects on a hilltop or knoll. Factor $C_E$ does not have this factor of 2 as it is a factor originally related the shielding of electromagnetic waves by buildings. Telecommunication network operator experience has shown that cables installed on a hill or along a ridge have a much higher exposure to direct strikes than cables installed on flat ground. To take this higher exposure into account, when considering direct strikes to an aerial or underground cable installed on a hill or along a ridge, a factor of 2 is recommended. + +The frequency of damage for aerial and buried cables ( $F'_{Va}$ and $F'_{Vb}$ ) can be calculated by: + +$$F'_{Va} = 2N_g \times [L - 3(H_a + H_b)] \times D \times p(I_a) \times C_e \times 10^{-6} \text{ [damages/year]}$$ + +$$F'_{Vb} = 2N_g \times [L - 3(H_a + H_b)] \times D \times p(I_a) \times C_e \times 10^{-6} \text{ [damages/year]}$$ + +NOTE – The modified factor $C_e$ is now used for the ITU-T K.47-type calculation. The factor D is calculated as follows. + +#### a) Buried cable + +The striking distance for buried cables is calculated as a function of earth resistivity, as follows: + +$$D = 0.482 (\rho)^{1/2} \quad \text{for } \rho \leq 100 \Omega \cdot m$$ + +$$D = 2.91 + 0.191 (\rho)^{1/2} \quad \text{for } 100 \Omega \cdot m < \rho < 1000 \Omega \cdot m$$ + +$$D = 0.283 (\rho)^{1/2} \quad \text{for } \rho \geq 1000 \Omega \cdot m$$ + +#### b) Aerial cables + +For aerial cables, the striking distance is given by the following equation: + +$$D = 3H[m]$$ + +where: + +H line height [m], which shall be between 4 m and 15 m. + +Where the value of the resistivity is not known, it is recommended that a value of 400 ohm.m be used. + +### IV.2 Assessment of Factor $P_{LD}$ for shielded cables + +Table B.8 of [IEC 62305-2] is calculated assuming a soil resistivity of 100 ohm.m. If Table B.8 is used for a structure in a high resistivity area the risk assessment may indicate that protection is not required. Where the soil resistivity is greater than 100 ohm.m, it is more accurate to use the following formulas from [b-ITU-T K.47]: + +$$I_s = \frac{10^3 U_w}{K R \rho^{1/2}}$$ + +where: + +$K$ is the waveshape factor for lightning current, $K = 8 \text{ (m/}\Omega)^{1/2}$ ; + +$R$ is the sheath resistance per unit length, in $\Omega/\text{km}$ (for cable with sheath and armouring, $R$ is given by the parallel association between the sheath and the armouring resistance values per unit length); + +$U_w$ is the hazardous voltage (4 kV) as indicated in Table VI.2 of [ITU-T K.89]; + +$\rho$ is the soil resistivity, in $\Omega\cdot\text{m}$ . + +Now the failure current $I_a = 2 \times I_s$ . + +The reduction factor $P_{LD}$ is the probability of $I_a$ occurring and this is determined by + +$p(I_a)$ is the stroke current probability factor: + +$$p(I_a) = 10^{-2} \exp(a - b I_a) \quad \text{for } I_a \geq 0$$ + +where: + +$$\begin{array}{lll} a = 4.605 & \text{and} & b = 0.0117 & \text{for } I_a \leq 20 \text{ kA} \\ a = 5.063 & \text{and} & b = 0.0346 & \text{for } I_a > 20 \text{ kA} \end{array}$$ + +# Appendix V + +## Mechanisms of damage + +(This appendix does not form an integral part of this Recommendation.) + +### V.1 Electric shock + +Figure V.1 shows a touch potential outside the structure. Figures V.2-V.9 illustrate the mechanisms by which customers, inside the structure, are exposed to electric shock. These can be summarized as the following. + +- Lightning strike to structure: + - touch potential earthed object to floor; + - touch potential earthed object to remote telecommunication earth; + - touch potential floor to remote telecommunication earth. +- Lightning strike to power line: + - touch potential earthed object to floor; + - touch potential earthed object to remote telecommunication earth; + - touch potential floor to remote telecommunication earth. +- Lightning strike to telecommunication line: + - touch potential telecommunication line to earthed object; + - touch potential telecommunication line to floor. + +![Diagram illustrating a direct lightning strike to a structure, showing touch potential between the structure and the ground outside.](5d782eeb9d1e5871d7f09e0ccdd4cdf1_img.jpg) + +The diagram shows a cross-section of a house labeled 'User environment'. A lightning bolt strikes the roof. Inside the house, a person is standing and touching a vertical metal pipe. A dashed vertical line with arrows at both ends, labeled 'V', indicates the touch potential between the person's hand and the floor. Outside the house, to the left, a resistor symbol labeled 'R' is connected between the ground and a point on the ground surface. To the right, a 'Power' line enters the house through a transformer-like symbol. The house has a grounding system connected to the earth, represented by a standard ground symbol at the base of the wall. + +Diagram illustrating a direct lightning strike to a structure, showing touch potential between the structure and the ground outside. + +NOTE – This risk is **not** included in this Recommendation. + +**Figure V.1 – Direct strike to structure (touch potential between the structure and the ground outside the structure)** + +![Diagram of a house showing a direct lightning strike to the roof. Inside the house, a person is touching an appliance that is connected to earth. A dashed arrow labeled 'V' indicates the touch potential between the appliance and the floor. The floor is shown with a resistor symbol labeled 'R' connected to earth.](77959075c823bb5169480d7b8ff82a63_img.jpg) + +The diagram shows a cross-section of a house labeled "User environment". A lightning bolt strikes the roof. Inside, a person is touching an appliance. A dashed arrow labeled $V$ points from the appliance to the floor. The floor is connected to earth through a resistor symbol labeled $R$ . To the right, a "Power" line enters the house and is connected to earth. + +Diagram of a house showing a direct lightning strike to the roof. Inside the house, a person is touching an appliance that is connected to earth. A dashed arrow labeled 'V' indicates the touch potential between the appliance and the floor. The floor is shown with a resistor symbol labeled 'R' connected to earth. + +NOTE – This risk is **not** included in this Recommendation. + +**Figure V.2 – Direct strike to structure (touch potential between +an earthed object and the floor of the structure)** + +![Diagram of a house showing a direct lightning strike to the roof. Inside the house, a person is touching a telecommunications line that is connected to remote earth. A dashed arrow labeled 'V' indicates the touch potential between the person and the telecommunications line.](9f6dec4d4e9fde40bce018861ef1278e_img.jpg) + +The diagram shows a cross-section of a house labeled "User environment". A lightning bolt strikes the roof. Inside, a person is touching a line labeled "Telecommunications line connected to remote earth". A dashed arrow labeled $V$ points from the person to this line. To the right, a "Power" line enters the house and is connected to earth. + +Diagram of a house showing a direct lightning strike to the roof. Inside the house, a person is touching a telecommunications line that is connected to remote earth. A dashed arrow labeled 'V' indicates the touch potential between the person and the telecommunications line. + +NOTE – This risk is **not** included in this Recommendation. + +**Figure V.3 – Direct strike to structure (touch potential between an earthed object +and the telecommunication line which is connected to a remote earth)** + +![Diagram of a house showing a direct lightning strike to the structure. A lightning bolt strikes the roof, and the current flows through the structure's grounding system. A person inside the 'User environment' is shown touching a 'Telecommunications line connected to remote earth', which is at a different potential than the floor. The floor is connected to earth through a resistor labeled 'R'. A dashed arrow labeled 'V' indicates the touch potential between the floor and the telecommunications line.](5eb69662cc4fa7d0d49b4eb22951c204_img.jpg) + +Diagram of a house showing a direct lightning strike to the structure. A lightning bolt strikes the roof, and the current flows through the structure's grounding system. A person inside the 'User environment' is shown touching a 'Telecommunications line connected to remote earth', which is at a different potential than the floor. The floor is connected to earth through a resistor labeled 'R'. A dashed arrow labeled 'V' indicates the touch potential between the floor and the telecommunications line. + +NOTE – This risk is included in this Recommendation. + +**Figure V.4 – Direct strike to structure (touch potential between the structure floor and the telecommunication line which is connected to a remote earth)** + +It should be noted that although the lightning strikes the structure and goes to earth, the solution to reducing this specific risk is to install point of entry SPDs on the telecommunication line, which will bond the telecommunication line to the MET under surge conditions. + +![Diagram of a house showing a direct lightning strike to an overhead power line. A lightning bolt strikes the power line, and the current flows through the power line's grounding system. A person inside the 'User environment' is shown touching an 'earthed object' (like a metal appliance), which is at a different potential than the floor. The floor is connected to earth through a resistor labeled 'R'. A dashed arrow labeled 'V' indicates the touch potential between the floor and the earthed object.](f5deee2f3301ee351c4008283ffafbb3_img.jpg) + +Diagram of a house showing a direct lightning strike to an overhead power line. A lightning bolt strikes the power line, and the current flows through the power line's grounding system. A person inside the 'User environment' is shown touching an 'earthed object' (like a metal appliance), which is at a different potential than the floor. The floor is connected to earth through a resistor labeled 'R'. A dashed arrow labeled 'V' indicates the touch potential between the floor and the earthed object. + +NOTE – This risk is **not** included in this Recommendation. + +**Figure V.5 – Direct strike to overhead power line (touch potential between an earthed object and the floor of the structure)** + +![Diagram of a house showing a direct lightning strike to a power line. A lightning bolt strikes a power line labeled 'Power'. Inside the house, labeled 'User environment', a person is touching a device connected to a 'Telecommunications line connected to remote earth'. A dashed line with a downward arrow indicates a touch potential 'V' between the person and the ground.](9a5927586a691c4908aa2cf98bd47ebb_img.jpg) + +Diagram of a house showing a direct lightning strike to a power line. A lightning bolt strikes a power line labeled 'Power'. Inside the house, labeled 'User environment', a person is touching a device connected to a 'Telecommunications line connected to remote earth'. A dashed line with a downward arrow indicates a touch potential 'V' between the person and the ground. + +NOTE – This risk is currently **not** included in this Recommendation. + +**Figure V.6 – Direct strike to a power line (touch potential between an earthed object and the telecommunication line which is connected to a remote earth)** + +![Diagram of a house showing a direct lightning strike to a power line. A lightning bolt strikes a power line labeled 'Power'. Inside the house, labeled 'User environment', a person is touching a device connected to a 'Telecommunications line connected to remote earth'. A dashed line with a downward arrow indicates a touch potential 'V' between the person and the ground. The ground is represented by a resistor labeled 'R' connected to earth.](c99bf3a0530a3e58f5f2d2790ba7441b_img.jpg) + +Diagram of a house showing a direct lightning strike to a power line. A lightning bolt strikes a power line labeled 'Power'. Inside the house, labeled 'User environment', a person is touching a device connected to a 'Telecommunications line connected to remote earth'. A dashed line with a downward arrow indicates a touch potential 'V' between the person and the ground. The ground is represented by a resistor labeled 'R' connected to earth. + +NOTE – This risk is considered in this Recommendation. + +**Figure V.7 – Direct strike to a power line (touch potential between the structure floor and the telecommunication line which is connected to a remote earth)** + +It should be noted that although the lightning strikes the power line and goes to earth, the solution to reducing this specific risk is to install point of entry SPDs on the telecommunication line, which will bond the telecommunication line to the MET under surge conditions. + +![Diagram of a house showing a direct strike to a telecommunication line. A lightning bolt strikes the telecommunication line outside the house. Inside the house, labeled 'User environment', a person is touching the telecommunication line. A dashed line with a downward arrow indicates a touch potential 'V' between the person and an earthed object (the power line mast). The power line is also shown entering the house and being earthed.](0b7849dae424b0dd33e6386d2384643a_img.jpg) + +Diagram of a house showing a direct strike to a telecommunication line. A lightning bolt strikes the telecommunication line outside the house. Inside the house, labeled 'User environment', a person is touching the telecommunication line. A dashed line with a downward arrow indicates a touch potential 'V' between the person and an earthed object (the power line mast). The power line is also shown entering the house and being earthed. + +NOTE – This risk is currently **not** considered in this Recommendation. + +**Figure V.8 – Direct strike to telecommunication line (touch potential between the telecommunication line and an earthed object)** + +![Diagram of a house showing a direct strike to a telecommunication line. A lightning bolt strikes the telecommunication line outside the house. Inside the house, labeled 'User environment', a person is touching the telecommunication line. A dashed line with a downward arrow indicates a touch potential 'V' between the person and the structure floor. The structure floor is represented by a zigzag resistor symbol labeled 'R' connected to earth. The power line is also shown entering the house and being earthed.](9252ccfbbe9e34cb108f0060f2b563f1_img.jpg) + +Diagram of a house showing a direct strike to a telecommunication line. A lightning bolt strikes the telecommunication line outside the house. Inside the house, labeled 'User environment', a person is touching the telecommunication line. A dashed line with a downward arrow indicates a touch potential 'V' between the person and the structure floor. The structure floor is represented by a zigzag resistor symbol labeled 'R' connected to earth. The power line is also shown entering the house and being earthed. + +NOTE – This risk is considered in this Recommendation. + +**Figure V.9 – Direct strike to telecommunication line (touch potential between the telecommunication line and the structure floor)** + +### V.2 Fire or explosion + +A strike to the structure may cause a fire or explosion due an electrical arc occurring. This arc can occur in two ways as follows. + +- The flash directly arcs to wiring or metallic parts within the roof or walls of the building (includes strike to LPS). +- The resulting EPR due to current conducted in the structure earth: + - causes a flashover in the mains-powered telecommunication equipment or telecommunication equipment with an SELV port; + - causes excessive current in SPDs; + - causes a flashover to a telephone or to the internal cable. +- A strike to the power line causes an EPR. The resulting EPR: + - causes a flashover in the mains-powered telecommunication equipment or telecommunication equipment with an SELV port; + - causes excessive current in SPDs; + - causes a flashover to a telephone or to the internal cable. +- A strike to the telecommunication line: + - causes a flashover in the mains-powered telecommunication equipment or telecommunication equipment with an SELV port; + - causes excessive current in SPDs; + - causes a flashover to a telephone or to the internal cable. + +# Appendix VI + +## Required current or voltage to cause injury + +(This appendix does not form an integral part of this Recommendation.) + +The energy developed by the lightning overvoltage across the human body impedance could be hazardous. The information provided in this appendix is based on [b-Day]. + +The evaluation of the risk of injury to a person touching electrical and electronic equipment inside a structure due to lightning requires the investigation of several scenarios relevant to the hazard of electric shock in the event of lightning overvoltages incident on electrical and/or electronic equipment. + +The first scenario is related to overvoltages coming from a hazardous circuit, i.e., the mains, due to flashes to or near a power line. If the insulation between the outer enclosure part in direct contact with the human body and the hazardous circuit breaks down during the lightning surge, the user of the equipment inside the structure is exposed to overvoltages which can cause an injury depending on the energy dissipated through the human body. The user can also be exposed to the hazardous circuit. + +The second scenario is related to overvoltages coming from the telecommunication or signal circuit due to flashes to or near the telecommunication or signal line. If the insulation between the outer enclosure part, in direct contact with the human body, and the telecommunication or signal circuit breaks down, the user will be exposed to overvoltages. This could cause an injury depending of the energy dissipated through the human body. A failure of the insulation between the telecommunication or signal circuit and the hazardous circuit, i.e., the mains, can result in hazardous condition as in the first scenario. + +A strike to, or near to, the structure can cause the above scenarios. + +The risk assessment of injury to persons touching electrical and electronic equipment inside a structure requires the evaluation of the above mentioned hazardous overvoltages causing failure of circuit insulation. + +In order to more accurately calculate the risk of injury, the hazardous voltage needs to be determined. This has been determined for two waveshapes using data from [b-IEC 60479-1] and [b-IEC 60479-2]. The waveshape used for direct strikes is 10/350 $\mu\text{s}$ , as indicated by Annex E of [b-IEC 62305-1], and for indirect strikes is 8/20 $\mu\text{s}$ . + +The impulse peak current flowing through the human body impedance $R_U$ is given by the following equation: + +$$I_{Cp} = \frac{U_U}{R_U}$$ + +where: + +$U_U$ is the voltage drop on the human body resistance; + +$R_U$ is the human body resistance assumed equal to 500 $\Omega$ ; + +According to [b-IEC 60479-2], the sinusoidal current magnitude ( $I_{Brms}$ ) having the same specific fibrillating energy of the impulse current ( $I_{Cp}$ ) of a capacitor discharge, with the time constant $T$ , is given by the following equation: + +$$I_{Cp} = \sqrt{6} \times I_{Brms}$$ + +The impulse duration ( $t_i$ ) is assumed equal to $3 \times T$ [b-IEC 60479-2] + +$$t_i = 3 \times 1.44 \times T_2$$ + +where: + +$T_2$ is the time to half value of the overvoltage waveshape. + +This duration gives the current flowing through the human body which can cause a fibrillation risk of 5% in the curve C2 of Figure VI.1, taken from [b-IEC 60479-2]. + +Neglecting the contact resistance of the user's feet to earth, then $U_U$ is equal to peak value of the overvoltage $U_p$ . Table VI.1 gives the peak value $U_p$ for the various waveshapes. However, the peak value of the overvoltage should be at least equal to the insulation voltage withstand value (e.g., 4 kV for equipment installed in category II of LV system and complying with basic resistibility requirements). + +NOTE – The effects of contact resistance are taken into account in the risk component through the evaluation of the loss, according to the IEC approach [IEC 62305-2]. + +![Figure VI.1: Threshold of ventricular fibrillation. A log-log plot showing the duration of impulse t_i [ms] on the y-axis (0.1 to 10) versus body current I_B rms [mA] on the x-axis (100 to 10,000). Three curves are shown: C1 (solid line, no fibrillation), C2 (dashed line, 5% fibrillation), and C3 (dashed line, 50% fibrillation). The curves show that as the body current increases, the duration of the impulse required to cause fibrillation decreases. C1 is the leftmost curve, followed by C2, and then C3.](4bff5f22997753bcf1997c715118012d_img.jpg) + +Figure VI.1: Threshold of ventricular fibrillation. A log-log plot showing the duration of impulse t\_i [ms] on the y-axis (0.1 to 10) versus body current I\_B rms [mA] on the x-axis (100 to 10,000). Three curves are shown: C1 (solid line, no fibrillation), C2 (dashed line, 5% fibrillation), and C3 (dashed line, 50% fibrillation). The curves show that as the body current increases, the duration of the impulse required to cause fibrillation decreases. C1 is the leftmost curve, followed by C2, and then C3. + +NOTE – Figure 20 of [b-IEC 60479-2]. + +**Figure VI.1 – Threshold of ventricular fibrillation (curve C1: no fibrillation, C2: 5 % of fibrillation, C3: 50 % of fibrillation)** + +**Table VI.1 – Impulse peak voltage $U_p$ and duration ( $t_i$ ) causing a 5% probability of fibrillation risk** + +| $T_2$
( $\mu\text{s}$ ) | $T_i$
(ms) | $I_{Brms}$
(A) | $I_{Cp}$
(A) | $U_p$
(kV) | +|----------------------------|---------------|-------------------|-----------------|---------------| +| 700 | 3.024 | 1.2 | 3 | 1.5 | +| 350 | 1.512 | 2 | 5 | 2.5 | +| 20 | 0.0864 | 13 | 32 | 16 | + +A lightning flash near a power line causes an induced overvoltage at the equipment input inside the building which is assumed to be represented by a time to half value in order of $20 \mu\text{s}$ , as shown in [b-Day]. In this case, $U_U$ is equal to peak value $U_p$ of the overvoltage, Table VI.1 gives the peak value $U_p$ of about 16 kV. + +To consider the likely effects of a lightning surge to the power or telecommunication line it is necessary to look at the various types of equipment. The standard [b-IEC 60950-1] defines classes of equipment as follows. + +Class I equipment: Equipment where protection against electric shock is achieved by: + +- using basic insulation and +- providing a means of connection to the protective earthing conductor in the building wiring those conductive parts that are otherwise capable of assuming hazardous voltages if the basic insulation fails. + +NOTE – Class I equipment may have parts with double insulation or reinforced insulation. + +Class II equipment: Equipment in which protection against electric shock does not rely on basic insulation only, but in which additional safety precautions, such as double insulation or reinforced insulation are provided, there being no reliance on protective earthing. + +Class III equipment: Equipment in which protection against electric shock relies upon supply from SELV circuits and in which hazardous voltages are not generated. + +Based on these three definitions, five types of equipment will be considered as follows. + +### 1 Remote powered telephone + +![Diagram of a remote powered telephone system showing a handset connected to a base unit, which is connected to a telecom line, with a person standing nearby.](48f209b7c0c1f91af40cfc3466dbd534_img.jpg) + +The diagram illustrates a remote powered telephone system. On the left, a dashed rectangular box represents the telephone base unit, with the label 'Remote powered telephone' above it. A handset is shown resting on top of this box. A line connects the handset to a horizontal line labeled 'Telecoms'. To the right of the 'Telecoms' line, a stick figure representing a person is standing on a horizontal ground line. The person's right hand is touching the 'Telecoms' line, and their feet are on the ground, illustrating a potential path for current flow during a lightning strike. + +Diagram of a remote powered telephone system showing a handset connected to a base unit, which is connected to a telecom line, with a person standing nearby. + +**Figure VI.2 – Remote powered telephone** + +**Strike to the telecommunication line:** The hazardous voltage is 1.5 kV (10/700 µs). However this is below the breakdown voltage of the handset required by [b-IEC 60950-1]. Section 6.2.2.1 of this standard requires an impulse insulation withstand voltage of 2.5 kV. In this case, the hazardous voltage equals the breakdown voltage. Some national regulators may require a higher breakdown voltage e.g., Australia, which requires 7 kV. + +### 2 Class I equipment + +![Diagram of Class I equipment showing a power transformer with L, N, and E windings connected to a dashed box labeled 'Class I equipment'. A person is shown touching the equipment, and a 'Telecoms' line is connected to it. The entire system is connected to a common earth plane.](5db6545aedab79741ebae9b27bb363b3_img.jpg) + +The diagram illustrates Class I equipment. On the left, a power transformer is shown with three windings labeled L (Live), N (Neutral), and E (Earth/Ground). The L and N windings are connected to a dashed rectangular box representing the 'Class I equipment'. The E winding is connected to a common earth plane at the bottom. A person is depicted touching the top of the Class I equipment box. A horizontal line labeled 'Telecoms' is connected to the right side of the Class I equipment box. The entire system, including the transformer, equipment, person, and telecoms line, is shown relative to a common earth plane. + +Diagram of Class I equipment showing a power transformer with L, N, and E windings connected to a dashed box labeled 'Class I equipment'. A person is shown touching the equipment, and a 'Telecoms' line is connected to it. The entire system is connected to a common earth plane. + +**Figure VI.3 – Class I equipment** + +**Strike to power line:** A flashover primary to secondary would result in a $V = L \times di/dt$ with a short tail ( $<5 \mu\text{s}$ ). The mains is earthed and the hazardous voltage is 16 kV (8/20 $\mu\text{s}$ ). + +**Strike to the telecommunication line:** The hazardous voltage is 1.5 kV (10/700 $\mu\text{s}$ ). There are two possible breakdown paths. One is to earth (breakdown requirement is 1.5 kV AC) and the other is to the user (breakdown requirement is 1.5 kV AC). It is assumed for Class I equipment that there will be earthed SPDs on the telecommunication line within the equipment. Operation of these SPDs will ensure a current path to earth resulting in a $V = L \times di/dt$ with a short tail ( $<5 \mu\text{s}$ ). The mains is earthed and the hazardous voltage becomes 16 kV (8/20 $\mu\text{s}$ ). + +### 3 Class II equipment + +![Diagram of Class II equipment showing a power transformer with L, N, and E windings connected to a dashed box labeled 'Class II equipment'. A person is shown touching the equipment, and a 'Telecoms' line is connected to it. The E winding is not connected to earth.](683f755e8456c884716de4fce48c7e63_img.jpg) + +The diagram illustrates Class II equipment. On the left, a power transformer is shown with three windings labeled L (Live), N (Neutral), and E (Earth/Ground). The L and N windings are connected to a dashed rectangular box representing the 'Class II equipment'. The E winding is shown but is not connected to the common earth plane at the bottom. A person is depicted touching the top of the Class II equipment box. A horizontal line labeled 'Telecoms' is connected to the right side of the Class II equipment box. The system is shown relative to a common earth plane, but the equipment's earth winding is isolated from it. + +Diagram of Class II equipment showing a power transformer with L, N, and E windings connected to a dashed box labeled 'Class II equipment'. A person is shown touching the equipment, and a 'Telecoms' line is connected to it. The E winding is not connected to earth. + +**Figure VI.4 – Class II equipment** + +**Strike to power line:** A flashover primary to secondary may occur above 4 kV and the user is exposed to mains. The hazardous voltage is 4 kV. + +**Strike to the telecommunication line:** A flashover secondary to primary may occur above 4 kV and the user is exposed to mains. The hazardous voltage is 4 kV. + +In those cases where the mains current will be disconnected due to the operation of an EBR, RCCB or RCD, the user is still exposed to a hazardous lightning overvoltage of 4 kV, or greater, with a 10/700 waveshape. + +### 4 Class III equipment with a Class I power supply + +![Diagram of Class III equipment with a Class I power supply showing a lightning strike on the power lines.](ec3647789b5c38fb686f2a0833324e79_img.jpg) + +The diagram illustrates a Class III equipment unit connected to a Class I power supply. The power supply is shown as a dashed box containing a transformer symbol, with input lines labeled L (Live), N (Neutral), and E (Earth). The output of the transformer is connected to a dashed box labeled 'Class III'. A lightning strike is depicted on the L and N lines, with a lightning bolt hitting the lines and a current path shown through the equipment and the user (represented by a stick figure) to the ground. The user is also connected to a 'Telecoms' line. The entire system is shown above a ground plane. + +Diagram of Class III equipment with a Class I power supply showing a lightning strike on the power lines. + +Figure VI.5 – Class III equipment with a Class I power supply + +**Strike to power line:** A flashover primary to secondary would result in a $V = L \times di/dt$ with a short tail ( $< 5 \mu\text{s}$ ). The mains is earthed and the hazardous voltage is 16 kV (8/20 $\mu\text{s}$ ). + +**Strike to the telecommunication line:** The hazardous voltage is 1.5 kV (10/700 $\mu\text{s}$ ). There are two possible breakdown paths. One is to earth (breakdown requirement is 1.5 kV AC) and the other is to the user (breakdown requirement is 1.5 kV AC). It is assumed, for Class III equipment with a Class I power supply, that there will be earthed SPDs on the telecommunication line within the equipment. Operation of these SPDs will ensure a current path to earth resulting in a $V = L \times di/dt$ with a short tail ( $< 5 \mu\text{s}$ ). The mains is earthed and the hazardous voltage becomes 16 kV (8/20 $\mu\text{s}$ ). + +### 5 Class III equipment with a Class II power supply + +![Diagram of Class III equipment with a Class II power supply showing a lightning strike on the power lines.](1316d63eca7b84e13c27f55f0027b7b5_img.jpg) + +The diagram illustrates a Class III equipment unit connected to a Class II power supply. The power supply is shown as a dashed box containing a transformer symbol, with input lines labeled L (Live), N (Neutral), and E (Earth). The output of the transformer is connected to a dashed box labeled 'Class III'. A lightning strike is depicted on the L and N lines, with a lightning bolt hitting the lines and a current path shown through the equipment and the user (represented by a stick figure) to the ground. The user is also connected to a 'Telecoms' line. The entire system is shown above a ground plane. + +Diagram of Class III equipment with a Class II power supply showing a lightning strike on the power lines. + +Figure VI.6 – Class III equipment with a Class II power supply + +**Strike to power line:** A flashover primary to secondary may occur above 4 kV and the user is exposed to mains. The hazardous voltage is 4 kV. + +**Strike to the telecommunication line:** A flashover secondary to primary may occur above 4 kV and the user is exposed to mains. The hazardous voltage is 4 kV. + +In those cases where the mains current will be disconnected due to the operation of an EBR, RCCB or RCD, the user is still exposed to a hazardous lightning overvoltage of 4 kV, or greater, with a 10/700 waveshape. + +**Table VI.2 – Resulting hazardous peak voltage $U_p$** + +| Class of equipment | Hazardous voltage | +|--------------------------|---------------------------------------| +| Remote powered telephone | 4 kV lightning (10/700) | +| I | 16 kV lightning. (< 8/20 $\mu$ s) | +| II | 4 kV (AC mains or lightning (10/700)) | + +In conclusion, the impulse hazardous voltage of a remote powered telephone is a lightning overvoltage of 4 kV, or greater, with a 10/700 waveshape. + +- Class I equipment is therefore 16 kV as the tail of the waveshape will then become < 20 $\mu$ s (inductive voltage along the earth conductor). +- Class II equipment is 4 kV due to exposure to the mains voltage when the lightning surge damages the insulation between the telecommunication line and the mains circuit as well as the insulation to the user. In those cases where the mains current will be disconnected due to the operation of an EBR, RCCB or RCD, the user is still exposed to a lightning overvoltage of 4 kV or greater with a 10/700 waveshape. + +The worst-case scenario, considering all of the above methods of powering, is that the hazardous voltage is 4 kV. + +# Bibliography + +- [b-ITU-T K.12] Recommendation ITU-T K.12 (2010), *Characteristics of gas discharge tubes for the protection of telecommunications installations.* +- [b-ITU-T K.47] Recommendation ITU-T K.47 (2012), *Protection of telecommunication lines against direct lightning flashes.* +- [b-ITU-T K.67] Recommendation ITU-T K.67 (2006), *Expected surges on telecommunications and signalling networks due to lightning.* +- [b-IEC 60364-4-44] IEC 60364-4-44 (2007), *Low-voltage electrical installations – Part 4-44: Protection for safety – Protection against voltage disturbances and electromagnetic disturbances.* +- [b-IEC 60479-1] IEC 60479-1 (2005), *Effects of current on human beings and livestock – Part 1: General aspects.* +- [b-IEC 60479-2] IEC 60479-2 (2007), *Effects of current on human beings and livestock – Part 2: Special aspects.* +- [b-IEC 60950-1] IEC 60950-1 (2005); *Information technology equipment – Safety – Part 1: General requirements.* +- [b-IEC 62305-1] IEC 62305-1 (2010), *Protection against lightning – Part 1: General principles.* +- [b-IEC 62305-2 Ed.1] IEC 62305-2 Ed.1 (2006), *Protection against lightning – Part 2: Risk management.* +<[http://webstore.iec.ch/webstore/webstore.nsf/ArtNum\\_PK/35440?OpenDocument](http://webstore.iec.ch/webstore/webstore.nsf/ArtNum_PK/35440?OpenDocument)> +- [b-Day] Day, P., Pomponi, R., Tommasini R. (2008), *Injury to Persons Touching Electrical and Electronic Equipment Inside the Structure Due to Lightning.* In: 29th International Conference on Lightning Protection (ICLP2008), Uppsala, Sweden, 23-26 June 2008. + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|---------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git 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+Recommendation ITU-T K.92 + +![ITU logo](6ed175c791b5e156d9c98a8dbcc3318c_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a red lightning bolt striking it, symbolizing telecommunications. To the right of the globe, the text "International Telecommunication Union" is written in a blue sans-serif font, with the acronym "ITU" in a larger, bold blue font above it. + +ITU logo + + + +# Recommendation ITU-T K.92 + +# Conducted and radiated electromagnetic environment in home networking + +## Summary + +Recommendation ITU-T K.92 describes the home networking electromagnetic environment. It gives the typical conducted and radiated phenomena in the home networking environment, the attributes of the home networking environment and the specification of disturbance characteristics and levels. This Recommendation also provides guidance on how to evaluate the electromagnetic (EM) environment in home networking. + +This Recommendation also provides several case studies about the home networking environment and information on how to evaluate the electromagnetic (EM) environment in home networking. + +## History + +| Edition | Recommendation | Approval | Study Group | +|---------|----------------|------------|-------------| +| 1.0 | ITU-T K.92 | 2012-05-29 | 5 | + +## Keywords + +Electromagnetic environment, home networking. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2012 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|------|-----------------------------------------------------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 3.1 | Term defined elsewhere ..... | 1 | +| 3.2 | Term defined in this Recommendation ..... | 1 | +| 4 | Abbreviations and acronyms ..... | 2 | +| 5 | Home networking environment ..... | 3 | +| 5.1 | Description of home networking environment..... | 3 | +| 5.2 | Equipment installed in the home networking environment..... | 3 | +| 6 | Typical phenomena in home networking environment ..... | 4 | +| 7 | Disturbance characteristics and levels ..... | 5 | +| 7.1 | Attributes of home networking environment ..... | 5 | +| 7.2 | Specification of disturbance characteristics and levels ..... | 6 | +| 8 | Guidance on how to evaluate EM characteristics in the home networking environment ..... | 7 | +| 8.1 | Preparation for the evaluation ..... | 7 | +| 8.2 | Measurement ..... | 8 | +| 8.3 | Monitoring of the EM environment ..... | 9 | +| 8.4 | Analysis and mitigation..... | 10 | +| 8.5 | Evaluation report ..... | 11 | +| | Appendix I – Case studies in home networking environments..... | 12 | +| I.1 | Checklist of case studies..... | 12 | +| I.2 | Template for case studies ..... | 13 | +| I.3 | Case studies ..... | 14 | +| | Appendix II – Evaluation of the EM environment in home networking ..... | 22 | +| II.1 | Methods for finding EM sources in actual environments ..... | 22 | +| II.2 | Flow chart for solving EMI problems of home networking equipment..... | 23 | +| | Bibliography..... | 24 | + + + +# Recommendation ITU-T K.92 + +# Conducted and radiated electromagnetic environment in home networking + +# 1 Scope + +This Recommendation defines the electromagnetic environmental conditions in home environments where home networking devices are installed. This Recommendation applies to telecommunication equipment installed in home networking. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.34] Recommendation ITU-T K.34 (2003), *Classification of electromagnetic environmental conditions for telecommunication equipment – Basic EMC Recommendation*. +- [ITU-T K.37] Recommendation ITU-T K.37 (1999), *Low and high frequency EMC mitigation techniques for telecommunication installations and systems – Basic EMC Recommendation*. +- [ITU-T K.74] Recommendation ITU-T K.74 (2008), *EMC, resistibility and safety requirements for home network devices*. +- [CISPR 11] CISPR 11 (2009), *Industrial, scientific and medical equipment – Radio-frequency disturbance characteristics – Limits and methods of measurement*. +<[http://webstore.iec.ch/webstore/webstore.nsf/ArtNum\\_PK/43918](http://webstore.iec.ch/webstore/webstore.nsf/ArtNum_PK/43918)> +- [IEC 60050-161] IEC 60050-161-Amd. 2 (1999), *International Electrotechnical Vocabulary. Chapter 161: Electromagnetic compatibility*. +<[http://webstore.iec.ch/webstore/webstore.nsf/ArtNum\\_PK/22945?OpenDocument](http://webstore.iec.ch/webstore/webstore.nsf/ArtNum_PK/22945?OpenDocument)> +- [IEC 61000-2-5] IEC/TR 61000-2-5 (2011), *Electromagnetic compatibility (EMC) – Part 2-5: Environment – Description and classification of electromagnetic environments*. +<[http://webstore.iec.ch/webstore/webstore.nsf/ArtNum\\_PK/45165?OpenDocument](http://webstore.iec.ch/webstore/webstore.nsf/ArtNum_PK/45165?OpenDocument)> + +# 3 Definitions + +## 3.1 Term defined elsewhere + +This Recommendation uses the following term defined elsewhere: + +**3.1.1 electromagnetic environment** [IEC 60050-161]: Totality of electromagnetic phenomena existing at a given location. + +NOTE – In general, this totality is time-dependent and its description might need a statistical approach. + +## 3.2 Term defined in this Recommendation + +This Recommendation defines the following term: + +**3.2.1 EM source**: The object that may be at the origin of electromagnetic waves. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|-----------------------------------------| +| AC | Alternating Current | +| ASDL | Asymmetric Digital Subscriber Line | +| ATM | Automatic Teller Machine | +| CATV | Cable Television | +| CB | Citizen Band | +| DC | Direct Current | +| DVD | Digital Video Disc | +| EFT/B | Electrical Fast Transients/Bursts | +| EM | Electromagnetic | +| EMC | Electromagnetic Compatibility | +| EMI | Electromagnetic Interference | +| ESD | Electrostatic Discharge | +| FFT | Fast Fourier Transformation | +| FM | Frequency Modulation | +| IP | Internet Protocol | +| ISDN | Integrated Services Digital Networks | +| ISM | Industrial, Scientific and Medical | +| ITE | Information Technology Equipment | +| LAN | Local Access Network | +| ONU | Optical Network Unit | +| PC | Personal Computer | +| PLT | Power Line Telecommunication | +| PSTN | Public Switched Telephone Network | +| RADAR | Radio Detection And Ranging | +| REIN | Repetitive Electrical Impulsive Noise | +| STB | Set-Top Box | +| TE | Transverse Electric | +| TM | Transverse Magnetic | +| VCR | Video Cassette Recorder | +| VDSL | Very high speed Digital Subscriber Line | +| VDU | Visual Display Unit | +| Wi-Fi | Wireless Fidelity | +| xDSL | X-type Digital Subscriber Line | + +# 5 Home networking environment + +## 5.1 Description of home networking environment + +With the recent advances in telecommunication technologies, high-speed access networks, by which users can easily access networks, have been introduced in home environments. As a result, many users can now enjoy many network-based services, and many electronic devices are connected to the network so that home networks can be easily constructed. + +On the other hand, there are many wired and wireless technologies that have appeared on the market, and these kinds of technologies could be introduced in a home network environment. In these network configurations, several kinds of network-related equipment are introduced in the home and are set in close proximity to each other. + +The home networking environment refers to customer premises (residential location) environments. In accordance with Figure 1, the residential location exists in an area of land designated for the construction of domestic dwellings. The function of a domestic dwelling is to provide a place for one or more people to live in. + +![Figure 1: Concept of location classes. A Venn diagram showing three overlapping circles labeled 'Residential', 'Industrial', and 'Commercial'. The 'Residential' circle is on the left, 'Industrial' is on the top right, and 'Commercial' is on the bottom right. A dashed circle is centered within the 'Residential' circle, and an arrow labeled 'Home networking environment' points to it.](367926125450c2bc3f4bdca9d59a62ba_img.jpg) + +Figure 1: Concept of location classes. A Venn diagram showing three overlapping circles labeled 'Residential', 'Industrial', and 'Commercial'. The 'Residential' circle is on the left, 'Industrial' is on the top right, and 'Commercial' is on the bottom right. A dashed circle is centered within the 'Residential' circle, and an arrow labeled 'Home networking environment' points to it. + +Figure 1 – Concept of location classes + +## 5.2 Equipment installed in the home networking environment + +Any equipment within the home networking environment is connected to the telecommunication networks (e.g., public switched telephone networks (PSTNs), integrated services digital networks (ISDN), x-type digital subscriber lines (xDSL), etc.), local area networks (e.g., Ethernet, token ring, etc.) and similar networks. + +The home networking environment is characterized by the ad hoc location of telecom, electrical and electronic equipment used by the residents. Equipment items can therefore be placed in very high density. The typical locations include: + +- the home office desk, with PC located on/below the desk; VDU, speakers, printer, wireless keyboard and wireless mouse located on the desktop; laptops, portable telephone handset and/or cellular telephone handset located on the desktop, near to or in physical contact with one of the items; +- the 'adolescent's bedroom', which may contain the above described home office desk in addition to a TV set with DVD/VCR and games console. High-density locations typically access the internal low voltage power supply network via a single outlet socket that is fitted with a distribution board/power strip. + +A non-exhaustive list of the types of equipment present and operated within the home networking environment is presented below. + +- 1) Home network devices [ITU-T K.74]: + - a) telecommunication devices, such as ONUs, routers, or broadband modems; + - b) controlling devices with telecommunication ports, such as STBs; + - c) information technology equipment (ITE), such as PCs, with telecommunication ports. +- 2) Multimedia equipment, household equipment and ITE devices operate with home networking devices. + +At the boundary of the home networking environment, there is the following wireline infrastructure: + +- extension wiring of telecom network; +- coaxial distribution network; +- low-voltage power supply distribution network. + +# **6 Typical phenomena in home networking environment** + +The typical phenomena in home networking environment are: + +- a) Conducted low-frequency phenomena: + - harmonics of the fundamental power frequency; + - power supply network voltage amplitude and frequency changes; + - power supply network common-mode voltages; + - signalling voltages in power supply networks (0.1-3 kHz); + - induced low-frequency voltages; + - DC voltage in AC networks; + - lighting. +- b) Radiated low-frequency phenomena: + - magnetic fields (DC, railway, power system, power system harmonics, etc.); + - electric fields (DC lines, railway (16 2/3 Hz), power system (50-60Hz)). +- c) Conducted high-frequency phenomena: + - direct-conducted continuous wave; + - induced continuous wave; + - transients. +- d) Radiated high frequency phenomena: + - radiated (continuous wave) oscillatory disturbances; + - radiated (modulated) signal disturbances; + - radiated (transient) pulsed disturbances. +- e) Electrostatic discharge (ESD) phenomena + - conducted; + - radiated. + +Some of these phenomena may be generated by home networking, such as induced continuous wave. Some of these phenomena are generated by others but may interface with the home networking, such as ESD. The details of these phenomena are described in the basic EMC Recommendation, [ITU-T K.34] and in [IEC 61000-2-5]. In the context of the Recommendation and in accordance with the IEC EMC approach, the term "low frequency" applies to frequencies up to and including 9 kHz; the term "high frequency" applies to frequencies above 9 kHz. + +The case studies of the phenomena occurring in home networking environments are collected in Appendix I. + +# **7 Disturbance characteristics and levels** + +## **7.1 Attributes of home networking environment** + +The attributes of the home networking environment are: + +#### **Enclosure** + +- amateur radio further than 100 m; +- citizen band (CB) radio further than 20 m; +- broadcast transmitter operating below 1.6 MHz further than 5km; +- FM and TV transmitters further than 1 km; +- radiated signal from cellular communications systems and portable communication systems (e.g., base stations, hand-held transceivers, mobile phones, wireless phones, Bluetooth, Wi-Fi, etc.); +- paging systems, base stations, further than 1 km; +- aviation RADAR further than 5 km; +- high concentration of multimedia and household equipment; +- presence of microwave oven up to 1.5 kW; +- presence of medical equipment (Group 2 according to [CISPR 11]) further than 20 m; +- proximity to MV/LV substations further than 20 m; +- proximity to arc welders (mobile) further than 20 m; +- proximity to HV sub-stations further than 100 m; +- possible proximity to low power ISM; +- possible presence of audio/hearing aid systems. + +#### **AC power** + +- feeding MV- or HV-line further than 20 m; +- LV AC cabling; +- high concentration of switched mode power supplies; +- existence of PLT equipment; +- lighting. + +#### **Signal/control** + +- telecommunication cables or lines; +- cable TV; +- lines <30 m (this includes: Ethernet, security systems); +- lightning exposure; +- close coupling between signal systems and switched power systems. + +#### Reference + +- abundant metallic structures which may or may not be bonded or earthed; +- frequent interfaces of power and telecom (including local) systems; +- local earth can be absent, or present high impedance; +- multiple local earths might not be coordinated. + +#### Additional notes + +- interfaces with customer systems; +- HV lines may be routed over buildings. + +The attributes from home networking are: + +- high concentration of home network devices and many ITE devices, which may be connected into networks (such as LAN); +- high-speed, high-performance and continuously operating home network devices and other devices; +- several telecommunication cables connected with home network devices and other devices; +- switched mode power adapters of home network devices. + +## 7.2 Specification of disturbance characteristics and levels + +The disturbance characteristics and levels of the environment of customer premises are described in [ITU-T K.34] and clauses 8.3 and A.1 of [IEC 61000-2-5]. + +As examples, the characteristics of two phenomena are listed in the following table: + +**Table 1 – Examples of characteristics of phenomena** + +| Phenomena | Coupling path | Environmental parameter | +|-------------------------------------------|--------------------------------------------|---------------------------------------------------------------------------------------------------------| +| Electrostatic discharges (ESD) | Enclosure | 8 kV
In higher humidity environments, lower levels of ESD may occur; [IEC 61000-2-5] specifies 4 kV. | +| Electrical fast transients/bursts (EFT/B) | Signal line entering the building | Common mode
Amplitude 1000 V (peak)
Several events/week
Rise time 5 µs, impedance 50 Ω | +| | Signal lines remaining within the building | Common mode
Amplitude 1000 V (peak)
Several events/week
Rise time 5 µs, impedance 50 Ω | +| | AC power mains | Common mode
Amplitude 2000 V (peak)
Several events/week
Rise time 5 µs | + +NOTE – The characteristics of the other phenomena are described in [ITU-T K.34] and clauses 8.3 and A.1 of [IEC 61000-2-5]. + +# **8 Guidance on how to evaluate EM characteristics in the home networking environment** + +## **8.1 Preparation for the evaluation** + +#### **8.1.1 Basic records** + +The basic records could include the following elements: + +- 1) date, time, ambient temperature, humidity and actual positions on which the measurement will be made; +- 2) the types of home networking devices and their working mode and operation status; +- 3) the information on the location, e.g., building walls and rooms in the house, the surrounding structures like fencing, trees, radio base stations, electric and electrical installations; +- 4) the measuring instruments to determine EM levels, e.g., the kind of antenna, current/voltage probes, oscilloscope and spectrum analyser, etc. + +#### **8.1.2 Checking before measurement** + +Before the measurement, the following points could be checked: + +- (a) Frequency bandwidth for measurement + +Measuring instruments and probes have their own frequency bandwidths for measurements, so each one should be selected in accordance with the target EM sources. + +- (b) Separation of power supply for measuring instruments + +Without batteries, some measuring instruments require a commercial power supply, so power supply lines should be separated to avoid EM interferences. One way is to insert an insulation transformer with EMI filters to prevent EMI noise flowing into measuring systems. In addition, some problems like electric shocks caused by the earthing of measuring instruments should be avoided. + +- (c) Warming-up of measuring instruments + +To perform precise and re-reproducible measurements, measuring instruments should be warmed up. Taking at least 30 minutes to warm up measuring instruments for stable measurements is important. + +- (d) Site verification and calibration of measuring instruments + +It is recommended to perform auto calibrations after the warming-up period, if the measuring instruments have an auto calibration function. To perform precise and re-reproducible measurements, verifying the measuring instruments at the test site is important and required. + +#### **8.1.3 Finding EM sources** + +The home networking devices, ITE devices, household devices, ISM devices and other electric/electronic devices are EM sources. Before measurement it is important to find the location, check the set-up, cable connection and typical working modes of these EM sources. If there are sources of EM interference in the home networking environment, the procedure described in Appendix II should be used. + +## **8.2 Measurement** + +#### **8.2.1 Conducted measurement** + +##### **(1) Measurement on telecommunication cables** + +When measuring the EM level on telecommunication cables (lines), a noise-cut filter (insulating transformer) should be connected to the power line of the measuring instrument. The EM level on telecommunication lines is generally related to the common-mode (longitudinal mode), in which the noise propagated along the cable is compared to the earth (reference point). If the earthing cannot be set, conductive lines such as water pipes and steel frames of a house can be used. In this case, however, the earthing point should not be changed while measuring. + +Here, the EM level measured by current probes corresponds to the common-mode type. When using voltage probes (e.g., high-impedance probe), the common-mode noise on the telecommunication line should be separately measured, such as at L1- and L2-earthing points. + +To measure the normal-mode (differential mode/transverse mode) noise in telecommunication cables, the difference between two lines (L1 and L2) is calculated by subtracting measured voltages for L1 and L2. Some oscilloscopes have a differential mode, by which measured results at two channels can be subtracted from each other. To avoid electric shocks and malfunctions of telecommunication systems, normal-mode measurements should not be performed by using only one voltage probe. + +##### **(2) Measurement on AC power cable** + +As in the case for telecommunication lines, a noise-cut filter (the insulating transformer) should be connected to the measuring instrument. In addition, the target signal needs to be measured on the basis of a reference earthing point, and normal-mode noise on AC power lines should not be directly measured by a probe. Common mode noise on power cables can be effectively measured by current probes, but voltage probes can be effective for detecting detailed waveform information. Here, voltage probes should not be directly inserted into electric sockets to avoid electric shocks and short circuits (e.g., the common mode AC power voltage can be effectively measured via the power distribution transformer). It is necessary to check carefully which terminal voltage corresponds to the earthing and then select sensitivity of voltage probes such as 10:1 or 100:1. If there are EMI problems in the power systems, distortion waveforms are observed in common-mode noise measured at power cables. + +#### **8.2.2 Radiated measurement** + +A noise-cut filter should be set to the measuring instruments. For radiated measurement, the measuring instruments and sensors (EMI antenna, or EM-field sensor) should be selected according to the type of EM sources and their frequency range. In addition, the set-up points, heights, and distances from the noise sources to EMI antennas should also be checked. + +Because many EMI sensors for measuring radiated fields have directional patterns, the direction and the mode of electromagnetic waves (transverse magnetic, TM, or transverse electric, TE, wave modes) for measurement should be checked. It is recommended to measure vertical and horizontal components of radiated fields and then to check the compound value derived from two components to perform accurate evaluations. + +### **8.3 Monitoring of the EM environment** + +#### **8.3.1 Monitoring of power frequency electromagnetic fields** + +To monitor the strength of power frequency electromagnetic fields, the power frequency field strength meter could be used. With those strength meters, the electric field as well as the magnetic field can be measured. The distribution of monitoring sites should be set on the direction of electric or magnetic field. People conducting the measurements should be more than 2 m away from the EM sources to avoid electromagnetic field distortion. + +#### **8.3.2 Monitoring of radio frequency electromagnetic fields** + +The radio frequency field generally refers to the electromagnetic field above 9 kHz. When monitoring RF fields, the following points should be taken into consideration. + +##### **(1) Select the appropriate measuring instruments** + +To obtain a strict assessment of the EM environment, it is recommended to use the broadband field probes and the frequency-selective field probes simultaneously. The broadband probe provides an independent measurement of the frequency, which integrates all of the emissions in a desired frequency band. A broadband probe that covers the band of interest should be used. This probe should be isotropic and the isotropic deviation should be less than 2.5 dB for frequencies up to 3 GHz, and less than 3.5 dB for frequencies up to 6 GHz. Each one of the three field components should be measured at the same time in order to have a correct total field result. Besides, the probe should have a dynamic range adapted to the measurement levels. + +The purpose of using the frequency-selective field probes is to identify the contribution of each EM source and the impact of each EM source on the EM environment. + +##### **(2) Calibrate monitoring instruments in time** + +Measuring probes and instruments without calibration cannot be used to monitor the EM environment. + +##### **(3) Select the probe or antenna correctly according to the frequency band of the EM sources** + +The selection of broadband measuring probe is required to be in accordance with the frequency band. The frequency range of the measuring instruments should be sufficient to cover the frequencies of the EM field sources to be measured. To obtain an accurate measurement result, the monitoring frequency band of EM sources should be placed in the middle band portion of the probe. + +For the frequency-selective measurement, the choice of the antenna becomes very important. Generally, in the range from 150 kHz to 30 MHz the electric fields are measured, using an active rod antenna. In the range from 30 MHz to 300 MHz, the electric field is also measured, but using the half-wave element antenna or log-periodic antenna, with the length of the element appropriately adjusted to make it equal to half-wavelength of the measured electromagnetic waves. In the range from 300 MHz to 1 GHz, generally a log-periodic antenna is used. Above 1 GHz a double ridge waveguide horn antenna is recommended. + +##### **(4) Pay attention to the polarization of electromagnetic fields during monitoring** + +Generally, the transmission of television signals use horizontal polarization; the transmission of radio broadcasting communications signals use vertical polarization; and the radar and satellite earth stations use circular polarization or elliptical polarization. The measuring antenna should be placed with the same polarization. For circular or elliptical polarization measurement of the vertical and horizontal components is needed, and sometimes measurement at different angles. + +##### (5) Calibration of measuring instruments and probes + +In general, new instruments can automatically be adjusted to zero but some old instruments need to be adjusted to zero manually before the measurement. + +When the measurement is completed, the antenna calibration curve or calibration data, and all kinds of loss should be corrected. + +##### (6) Distribution of test sites + +When monitoring the omnidirectional radiation sources, select the sites on the direction and distance where large differences on the measurement environment existed; when monitoring the directional sources, select a number of points in the direction of maximum radiation. The measurement distances depend on the requirement of the monitoring standards. But in exceptional circumstances, measurement distances should be adjusted according to the local conditions. + +##### (7) Selection of the monitoring time + +Radio and television facilities are basically transmitting on the same power frequency. So the monitoring time can be selected in the morning, in the afternoon and in the evening for television facilities. For radio communication facilities, the monitoring time should be selected at the peak time of the communication. + +##### (8) Environmental conditions should meet the provisions of the standard + +If the environmental conditions cannot meet the provisions of the standard, it should be recorded on the report, along with a full estimate of the impact of environmental conditions. + +##### (9) Distance and height should be confirmed + +The relative distance and height from monitoring points to the target EM sources are two very important factors. + +## **8.4 Analysis and mitigation** + +#### **8.4.1 Analysis of measured signal** + +When performing time-domain measurements, the obtained signals provide effective information for discriminating EM sources and their effects on electrical equipment. Namely, by checking the amplitude, energy and duration of the obtained signal, the EM level and kinds of EM sources could be determined. The time-frequency transformation, such as FFT, gives qualitative information for discriminating the kinds of EM sources. However, it should be noted that original waveforms are often distorted, especially when the target EM signals are transient- or pulse-type; e.g., oscillations may be generated when the EMI noise is induced in the cables. Distortions due to EMI sensors may be observed. + +When performing frequency-domain measurements, the obtained signals also provide effective information for discriminating the kinds of EM sources and their effects on electrical equipment. Namely, by checking the amplitude, energy and resonance frequency, the EM level and kinds of EM sources could be effectively determined. Wireless-related signals generally generate higher harmonic components, so the maximum level of several resonance frequencies should be checked when identifying the kinds of EM sources. + +#### **8.4.2 Evaluating the EM environment and clarifying EMI sources** + +Evaluating measurement results is an important part of solving EMI. The following points should be taken into account in order to distinguish EMI sources. + +- 1) The level and frequency of the conducted and radiated emissions should be checked. Comparison between measured data and other related information is useful to find the trouble source. Items to be compared with the data are: + - immunity level with which the equipment complies; + - specifications of suspected equipment, such as clock or switching frequencies, and transmission rate. +- 2) The relationship between the trouble and the disturbances should be checked. The timing of the occurrences of disturbances and trouble is an important factor in distinguishing trouble sources. Items to be considered are: + - occurrence time, such as hour, duration and day of week; + - synchronization between disturbance and trouble; + - other information, such as the installation of new equipment, new construction, and power failures. + +#### **8.4.3 Mitigation techniques** + +For detailed mitigation techniques, see [ITU-T K.37]. + +## **8.5 Evaluation report** + +The evaluation report should include all test conditions and results together with the methods of measurement used. Included items in the report should be: + +- a) information from basic records; +- b) frequency bandwidth for measurement; +- c) instruments used; +- d) site verification results; +- e) EM sources position and cable layout; +- f) measurement results of frequency and level; +- g) analysis of measured signal; +- h) evaluation results and conclusions; +- i) mitigation information. + +# Appendix I + +## Case studies in home networking environments + +(This appendix does not form an integral part of this Recommendation.) + +### I.1 Checklist of case studies + +The case studies in this appendix are listed in Table I.1. + +**Table I.1 – Checklist of case studies** + +| Title of study case | Victim | Phenomena | Disturbing source | Detail table number | +|--------------------------------------------------------------------------------|--------------------------------------|-------------------|------------------------------------|---------------------| +| CATV interfered with by land mobile radio services | CATV | Radiated emission | Radio service on a taxi | Table I.4 | +| VDSL interfered with by a defective water feed pump | VDSL | Impulsive noise | Defective water feed pump | Table I.5 | +| Network trouble of wide area Ethernet caused by impulsive noise | Media converter of ATM online system | Impulsive noise | Elevator, room light | Table I.6 | +| xDSL disturbances in telecommunication networks caused by electrical equipment | xDSL devices | Crosstalk noise | Satellite receivers, AC-DC-adapter | Table I.7 | + +Table I.2 shows the case studies related to impulsive noise described in [ITU-T K.74]. + +**Table I.2 – Case studies from [ITU-T K.74]** + +| Title of study case | Victim | Phenomena | Disturbing source | Notes | +|---------------------------------------------------------------------------------------------------|-------------|----------------------------------------------|---------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Example of a problem in home networks – trouble for IPTV broadcasting service over DSL | TV over DSL | Impulsive noise | – | Appendix I of [ITU-T K.74] | +| Example of a problem in home networks – degradation of performance of ADSL service caused by REIN | ADSL | Repetitive electrical impulsive noise (REIN) | Switch power supply | Appendix II of [ITU-T K.74]
During the EMC test, downlink performance of ADSL can be degraded when the cable carrying ADSL service is moved towards the switch power unit | + +**Table I.2 – Case studies from [ITU-T K.74]** + +| Title of study case | Victim | Phenomena | Disturbing source | Notes | +|-----------------------------------------------------------------------------------------------------------|--------------------------------------|-----------------|----------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Example of a problem in home networks – trouble in a wide area Ethernet network caused by impulsive noise | Media converter of ATM online system | Impulsive noise | Elevator, room light | Appendix III of [ITU-T K.74]
As the AC power line of the room light was running in parallel with the communication line, the impulsive noise was inducted onto the communication line and came into the media converter. This room is an ATM booth in a shopping mall, and the network equipment could not be bonded to the earth conductor | + +### I.2 Template for case studies + +The following template may be used for collecting information of case studies in the home networking environment. + +**Table I.3 – Template of the information table for case studies** + +| | | | | | | +|-----------------------------------------------------------------------------------|------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------|------------------|-------|--------| +| Title | | | | | | +| Sort of trouble | | Acoustic noise, malfunction, disturbance, other ( ) | | | | +| | | More detail: | | | | +| Environment | Type | 1. Co-location
2. User building (used by one user/used by multiple users)
3. Detached house      4. Semi-detached house | | | | +| | Use | 1. Telecom centre                      2. Data centre
3. Office                      4. Residence                      5. Others ( ) | | | | +| Situation, configuration, measured data, etc. (Please add figures, if necessary.) | | | | | | +| | | | | | | +| Source of EM interference | | | | | | +| Type of the interference | | Characteristics of the interferences | | | | +| | | Type | Frequency (band) | Level | Others | +| Conducted | Voltage or current | Continuous | Hz | [ ] | | +| | | Impulsive | Hz | [ ] | | +| Radiated | Electromagnetic wave (field) | Continuous | Hz | [ ] | | +| | | Impulsive | Hz | [ ] | | + +### I.3 Case studies + +#### I.3.1 CATV interfered with by land mobile radio services + +The information of this case study is collected in the Table I.4. + +**Table I.4 – CATV interfered with by land mobile radio services** + +| | | | | | | | | | | +|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------|---------------------------------------|------------------|---------|--------|--|--|--|--| +| Title | CATV interfered by land mobile radio services | | | | | | | | | +| Sort of trouble | Disturbance | | | | | | | | | +| | More detail: radiated | | | | | | | | | +| Environment | Type | Co-location | | | | | | | | +| | Use | Residence | | | | | | | | +| Situation, configuration, measured data, etc. (Please add figures, if necessary.) | | | | | | | | | | +| Situation: RF leakages from CATV splitters cause interference with land mobile radio services. This has occurred when a taxi has been stopping nearby a tension pole on which a CATV splitter is mounted.
Configuration:
RF leakage from CATV: 447.246 MHz (–115 dB)
Taxi: 447.250 MHz (–117 dB)
Measurement set-up:
Distance = 10 m
Half-wave dipole antenna: V/H polarization
Receiver: detector = QP; resolution BW = 1 kHz | | | | | | | | | | +| Source of EM interference | | Land mobile radio service on the taxi | | | | | | | | +| Type of the interference | | Characteristics of the interferences | | | | | | | | +| | | Type | Frequency (band) | Level | Others | | | | | +| Conducted | Voltage or current | Continuous | 447.246 MHz | –115 dB | | | | | | +| | | Impulsive | Hz | [ ] | | | | | | +| Radiated | Electromagnetic wave (field) | Continuous | 447.250 MHz | –117 dB | | | | | | +| | | Impulsive | Hz | [ ] | | | | | | + +#### I.3.2 VDSL interfered with by a defective water feed pump + +The information of this case study is collected in Table I.5. + +**Table I.5 – VDSL interfered with by a defective water feed pump** + +| | | | | | | | | | | +|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------|----------------------------------------|--|--|--|--|--|--|--| +| Title | VDSL interfered by the defective water feed pump | | | | | | | | | +| Sort of trouble | Malfunction | | | | | | | | | +| | More detail: EMC problem occurred only when the defective feed pump was started or stopped | | | | | | | | | +| Environment | Type | User building (used by multiple users) | | | | | | | | +| | Use | Residence | | | | | | | | +| Situation, configuration, measured data, etc. (Please add figures, if necessary.) | | | | | | | | | | +| Figure I.1 shows the set-up of the VDSL system in the case of some cluster housing. The EMC problem was that the link between the VTU-O and the VTU-R was occasionally disconnected by a broadband impulsive conducted disturbance caused by the defective water feed pump. | | | | | | | | | | + +**Table I.5 – VDSL interfered with by a defective water feed pump** + +![Diagram of a VDSL system setup in cluster housing showing a defective water feed pump causing interference. The diagram includes an ONU connected to an optical fibre and an AC power line. The AC power line is connected to a defective feed pump and a VTU-O. The VTU-O is connected to a premises cable and a VTU-R. Measuring point 1 is on the AC power line, and measuring point 2 is on the premises cable. The diagram also shows 1φ 100V and 3φ 200V power lines.](812e188283162af0b54fb3e30ffee51b_img.jpg) + +The diagram illustrates a VDSL system setup in cluster housing. On the left, a building is shown with two power lines: a single-phase 1φ 100V line and a three-phase 3φ 200V line. The 1φ 100V line is connected to an Optical Network Unit (ONU). The 3φ 200V line is connected to a 'Defective feed pump'. The ONU is connected to a Virtual Terminal Unit - Optical (VTU-O) via an Ethernet cable. The VTU-O is also connected to the 1φ 100V AC power line. A 'Measuring point 1' is indicated on the AC power line between the defective feed pump and the VTU-O. The VTU-O is connected to a premises cable, which leads to a Virtual Terminal Unit - Remote (VTU-R). A 'Measuring point 2' is indicated on the premises cable between the VTU-O and the VTU-R. The diagram is labeled 'K.92(12)\_FI.1'. + +Diagram of a VDSL system setup in cluster housing showing a defective water feed pump causing interference. The diagram includes an ONU connected to an optical fibre and an AC power line. The AC power line is connected to a defective feed pump and a VTU-O. The VTU-O is connected to a premises cable and a VTU-R. Measuring point 1 is on the AC power line, and measuring point 2 is on the premises cable. The diagram also shows 1φ 100V and 3φ 200V power lines. + +**Figure I.1 – The set-up of a VDSL system in cluster housing** + +| | | | | | | +|---------------------------|------------------------------|--------------------------------------|----------------------|---------|--------| +| Source of EM interference | | The defective water feed pump | | | | +| Type of the interference | | Characteristics of the interferences | | | | +| | | Type | Frequency (band) | Level | Others | +| Conducted | Voltage or current | Continuous | Hz | [ ] | | +| | | Impulsive | Below and over 1 MHz | 33 Vp-p | | +| Radiated | Electromagnetic wave (field) | Continuous | Hz | [ ] | | +| | | Impulsive | Hz | [ ] | | + +As this EMC problem occurred only when the defective feed pump was started or stopped, the common-mode voltages of the electromagnetic disturbance were measured at two measuring points. The first measuring point was the AC power port of the VTU-O and second measuring point was the telecommunication port of the VTU-O. The broadband impulsive conducted disturbance at both the AC power and telecommunication ports of the VTU-O (measuring points 1 and 2) was seen to be coincident with the operation of the defective feed pump, as shown in Figure I.2. + +![Two oscilloscope waveforms showing broadband impulsive conducted disturbances. The top waveform is labeled 'AC power port' and shows a peak-to-peak voltage of 33 V. The bottom waveform is labeled 'Telecommunication port' and shows a peak-to-peak voltage of 17 V. Both waveforms have a vertical scale of 5V/div and a horizontal scale of 100 μsec/div.](60e9207be66a64332619bb4b667fe67b_img.jpg) + +The figure consists of two vertically stacked oscilloscope displays. The top display is labeled 'AC power port' and shows a noisy waveform with a peak-to-peak voltage of 33 V, indicated by a red double-headed arrow. The bottom display is labeled 'Telecommunication port' and shows a similar noisy waveform with a peak-to-peak voltage of 17 V, also indicated by a red double-headed arrow. Both displays have a vertical scale of 5V/div and a horizontal scale of 100 μsec/div. + +Two oscilloscope waveforms showing broadband impulsive conducted disturbances. The top waveform is labeled 'AC power port' and shows a peak-to-peak voltage of 33 V. The bottom waveform is labeled 'Telecommunication port' and shows a peak-to-peak voltage of 17 V. Both waveforms have a vertical scale of 5V/div and a horizontal scale of 100 μsec/div. + +**Figure I.2 – A broadband impulsive conducted disturbance at the AC power and telecommunication ports** + +Figure I.3 shows the FFT analysis result for the measured broadband impulsive conducted disturbance and the VDSL transmission signal at the telecommunication port of the VTU-O (measuring point 2). The measured broadband impulsive conducted disturbance has high-frequency components over 1 MHz, as with the VDSL transmission signal. + +Although most of the broadband impulsive conducted disturbances which can affect the performance of broadband telecommunication equipment may be electromagnetic disturbances caused by the defective electrical devices, these may have a wider bandwidth than the DSL transmission signal. Moreover, as it is difficult to identify the source of a disturbance and the responsibility of the EMC trouble caused by it may not be understood by costumers, the performance of DSL equipment against broadband impulsive conducted disturbances should be evaluated using electromagnetic disturbances that have a wider bandwidth than the DSL transmission bandwidth. + +![Figure I.3: FFT analysis result for the measured broadband impulsive conducted disturbance and the VDSL transmission signal at the telecommunication port of the VTU-O. The graph shows Common-mode voltage (dBV) on the y-axis from 0 to -100 and Frequency (MHz) on the x-axis from 0 to 30. The VDSL transmission signal is represented by a black line, and the impulsive disturbance is represented by a grey shaded area. The disturbance is most intense between 0 and 10 MHz, reaching levels near -100 dBV, while the VDSL signal shows specific spectral peaks across the 30 MHz range.](0f79a59f3766fc341ff688a23692c1d9_img.jpg) + +Figure I.3: FFT analysis result for the measured broadband impulsive conducted disturbance and the VDSL transmission signal at the telecommunication port of the VTU-O. The graph shows Common-mode voltage (dBV) on the y-axis from 0 to -100 and Frequency (MHz) on the x-axis from 0 to 30. The VDSL transmission signal is represented by a black line, and the impulsive disturbance is represented by a grey shaded area. The disturbance is most intense between 0 and 10 MHz, reaching levels near -100 dBV, while the VDSL signal shows specific spectral peaks across the 30 MHz range. + +**Figure I.3 – FFT analysis result for the measured broadband impulsive conducted disturbance and the VDSL transmission signal at the telecommunication port of the VTU-O** + +#### I.3.3 Network trouble of wide area Ethernet caused by impulsive noise + +The information of this case study is collected in Table I.6. + +**Table I.6 – Network trouble of wide area Ethernet caused by impulsive noise** + +| | | | +|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------|-----------------------| +| Title | Network trouble of wide area Ethernet caused by impulsive noise | | +| Sort of trouble | Disturbance | | +| | More detail: impulsive noise | | +| Environment | Type | Co-location | +| | Use | Office, shopping mall | +| Situation, configuration, measured data, etc. (Please add figures, if necessary.) | | | +|

Figure I.4 shows the configuration of an ATM online system. The network has a redundancy configuration, and consisted of a wide area Ethernet (main) and an integrated service digital network (ISDN). The trouble was that the wide area Ethernet could not hold the link in the data transfer state and the main line was changed to the ISDN line. The trouble occurred when the media converter had a malfunction caused by the impulsive noise conducted through the AC power line.

Image: Figure I.4: Network configuration diagram. On the left, 'Telecommunication centre' contains a 'Server' and 'Router' connected to a 'Media converter' and a 'DSU'. The 'Media converter' connects to 'Wide area Ethernet' (labeled '2) Linkdown'). The 'DSU' connects to 'ISDN'. On the right, 'Customer premises' contains a 'Media converter' (labeled '1) Multifunction') connected to 'Router (main)', 'Switching HUB', and 'Terminal (ATM)'. A 'DSU' and 'Router (backup)' are connected to the 'ISDN' line (labeled '3) Backup'). An 'Impulsive noise' lightning bolt symbol points from an AC power plug to the customer-side 'Media converter'.

| | | + +**Table I.6 – Network trouble of wide area Ethernet caused by impulsive noise** + +| Figure I.4 – The configuration of the ATM online system when network trouble occurred | | | | | | +|----------------------------------------------------------------------------------------------|--------------------|--------------------------------------|------------------|----------------------------------------------|--------| +| Source of EM interference | | Elevator and room light | | | | +| Type of the interference | | Characteristics of the interferences | | | | +| | | Type | Frequency (band) | Level | Others | +| Conducted | Voltage or current | Continuous | Hz | [ ] | | +| | | Impulsive | 1-10 kHz | 12 mA (Figure I.5)
2.8 KVp-p (Figure I.6) | | + +Figure I.5 shows the impulsive noise measured by an oscilloscope at the AC power line of the media converter. The noise was generated in sync with the operation of an elevator. + +![Oscilloscope screenshot showing two waveforms of noise current over time. The top waveform is a noisy baseline with a prominent spike highlighted by a yellow box and a blue arrow. The bottom waveform shows a more detailed view of the impulsive noise. Scale markers indicate 4 (mA/div) for vertical scale and 200 (msec/div) for the top trace, and 5 (msec/div) for the bottom trace. The time axis is labeled 'Time'.](45329c7d9aa2bd1290af5b2027f08d7e_img.jpg) + +Oscilloscope screenshot showing two waveforms of noise current over time. The top waveform is a noisy baseline with a prominent spike highlighted by a yellow box and a blue arrow. The bottom waveform shows a more detailed view of the impulsive noise. Scale markers indicate 4 (mA/div) for vertical scale and 200 (msec/div) for the top trace, and 5 (msec/div) for the bottom trace. The time axis is labeled 'Time'. + +**Figure I.5 – Noise current measured during elevator operation** + +Figure I.6 shows the impulsive noise measured at the AC power line of a room light when turned on/off. As the AC power line of the room light was in parallel with the communication line, the impulsive noise was induced in the communication line and came into the media converter. This room is an ATM booth in a shopping mall, and the network equipment could not be bonded to the earth conductor. + +![Two oscilloscope screenshots showing noise measurements. The left screen shows a current measurement with a peak-to-peak value of 25 A and a time scale of 500 ns/div. The right screen shows a voltage measurement with a peak-to-peak value of 2.8 kV and a time scale of 5 ms/div.](645bea0b27d63e4a9a300af5793ae7d2_img.jpg) + +The figure consists of two oscilloscope screenshots. The left screenshot displays a current waveform with a peak-to-peak value of 25 A. The time scale is 500 ns/div. The right screenshot displays a voltage waveform with a peak-to-peak value of 2.8 kV. The time scale is 5 ms/div. + +Two oscilloscope screenshots showing noise measurements. The left screen shows a current measurement with a peak-to-peak value of 25 A and a time scale of 500 ns/div. The right screen shows a voltage measurement with a peak-to-peak value of 2.8 kV and a time scale of 5 ms/div. + +Figure I.6 – Noise current and voltage measured when room light turned on/off + +#### I.3.4 xDSL disturbances in telecommunication networks caused by electrical equipment + +The information of this case study is collected in Table I.7. + +Table I.7 – xDSL disturbed by electrical equipment + +| | | | +|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------|---------------| +| Title | xDSL disturbances in telecommunication networks caused by electrical equipment | | +| Sort of trouble | Disturbance | | +| | More detail: common mode disturbances on the AC mains network to the telecommunication wiring | | +| Environment | Type | User building | +| | Use | Residence | +| Situation, configuration, measured data, etc. (Please add figures, if necessary.) | | | +|

Typical for DSL problems due to extremely high emissions from household appliances are:
significant reduction of the DSL performance or complete loss of connection for several subscribers in the vicinity of the interfering source;
interference to radio services in the medium- and short-wave frequency range.

Disturbing sources

The service personal mostly identifies defective switching power supplies as cause of the described DSL problems. These power supplies apparently work as intended but emit permanently a broadband noise spectrum on the AC power line (comparable to REIN ). Figure I.7 provides an example of the measurement result of the conducted emission (frequency domain) of such an interfering device that vastly exceeds the limits of [b-CISPR 22] for the AC ports.

| | | + +**Table I.7 – xDSL disturbed by electrical equipment** + +![Figure I.7: A line graph showing conducted emission levels (U/dBμV) versus frequency (f/kHz) on a logarithmic scale. The y-axis ranges from -10 to 80 dBμV, and the x-axis ranges from 100 to 30,000 kHz. A solid orange line represents the measured emission, which starts around 65 dBμV at 100 kHz, peaks at approximately 78 dBμV around 200 kHz, and then generally decreases to about 5 dBμV at 30,000 kHz. A dashed black line represents the average detector limit, which is constant at 60 dBμV. A solid black line represents the Class B limit, which is 55 dBμV from 100 kHz to 1,000 kHz, then drops to 45 dBμV until 5,000 kHz, and finally steps up to 50 dBμV for frequencies above 5,000 kHz. The label 'K.92(12)_Fl.7' is in the bottom right corner.](a848a8de7c2614546db51319bd55328f_img.jpg) + +Figure I.7: A line graph showing conducted emission levels (U/dBμV) versus frequency (f/kHz) on a logarithmic scale. The y-axis ranges from -10 to 80 dBμV, and the x-axis ranges from 100 to 30,000 kHz. A solid orange line represents the measured emission, which starts around 65 dBμV at 100 kHz, peaks at approximately 78 dBμV around 200 kHz, and then generally decreases to about 5 dBμV at 30,000 kHz. A dashed black line represents the average detector limit, which is constant at 60 dBμV. A solid black line represents the Class B limit, which is 55 dBμV from 100 kHz to 1,000 kHz, then drops to 45 dBμV until 5,000 kHz, and finally steps up to 50 dBμV for frequencies above 5,000 kHz. The label 'K.92(12)\_Fl.7' is in the bottom right corner. + +**Figure I.7 – Example of the conducted emission measured on the AC port of an interfering device (average detector, class B limits)** + +| | | | | | | +|---------------------------|--------------------|------------------------------------------------|------------------|---------|--------| +| Source of EM interference | | Satellite receivers, followed by AC-DC adapter | | | | +| Type of the interference | | Characteristics of the interferences | | | | +| | | Type | Frequency (band) | Level | Others | +| Conducted | Voltage or current | Continuous | Below 5 MHz | 70 dBμV | | +| | | Impulsive | Hz | [ ] | | + +##### Coupling paths to the telecommunication network and propagation + +Several paths for the coupling of the common mode disturbances on the AC mains network to the telecommunication wiring inside a building can exist. Two possible paths are shown in Figure I.8 schematically: (left) the common mode field coupling in a cable section where AC and telecommunication lines are close to each other (e.g., in cable ducts), and (right) the coupling within telecom devices (via stray capacitances and inductances, etc.). + +![Figure I.8: Coupling of common mode voltages and currents on the mains lines to the telecommunication wiring in buildings. The diagram is split into two panels. The left panel shows field coupling where a red arrow on a vertical conductor (mains line) is surrounded by green dashed circular arrows representing magnetic field lines. Blue curved arrows show the coupling of these fields to a nearby telecommunication cable. The right panel shows coupling via a telecom device, where a green rectangular box represents the device. Red arrows enter the device from the top and bottom, and dashed purple arrows show the internal coupling to the internal wiring, which then exits as a blue arrow on the right.](aaf3e6e44cdeabd6d1df869c5f392ea1_img.jpg) + +Figure I.8: Coupling of common mode voltages and currents on the mains lines to the telecommunication wiring in buildings. The diagram is split into two panels. The left panel shows field coupling where a red arrow on a vertical conductor (mains line) is surrounded by green dashed circular arrows representing magnetic field lines. Blue curved arrows show the coupling of these fields to a nearby telecommunication cable. The right panel shows coupling via a telecom device, where a green rectangular box represents the device. Red arrows enter the device from the top and bottom, and dashed purple arrows show the internal coupling to the internal wiring, which then exits as a blue arrow on the right. + +**Figure I.8 – Coupling of common mode voltages and currents on the mains lines to the telecommunication wiring in buildings: field coupling (left) and coupling via telecom device** + +The coupled common mode signal on the telecommunication cable is converted into differential mode due to the limited balance of the wire-pairs inside the cable (mode conversion). These differential mode signals on the wire-pairs propagate and interfere with DSL signals if they cover the same frequency range. + +# Appendix II + +## Evaluation of the EM environment in home networking + +(This appendix does not form an integral part of this Recommendation.) + +It is important to evaluate the EM environment to solve the problem of interference. Methodologies for measuring the EM environment are described in clause 8 of this Recommendation. Involved parties should measure the EM environment in the place where the problem occurred. Both conducted and radiated electromagnetic environments should be taken into account. Also, in some cases, an EM disturbance may come from outside the place where the problem occurred. Hence, measurement should be performed not only in the place where the problem has occurred, but also in the vicinity of that place. + +When problems of telecom equipment occur, many causes could be considered. EMI is one of the possible causes, but other possible causes should be checked; for example, a hardware malfunction, protocol problems and software glitches. After other possible causes have been ruled out, and EMI is suspected as a cause of the problem, compliance with the EMC requirements of both suspected and affected equipment should be checked. + +### II.1 Methods for finding EM sources in actual environments + +When the cause of EMI problems cannot be clarified by an on-site investigation, one effective way to find EMI sources is to set EMI devices and sensors near the EMI-affected equipment. + +If the EMI-affected equipment can emit alarm signals for indicating operating problems, the time of those signals should be simultaneously recorded. Because the alarm signal is emitted after some time, it is not recommended to use the alarm signal as a trigger signal for measuring noise. Here, if the target EMI source is wireless generated, it may continue for more than several seconds, so the alarm signal may be used as a trigger signal for the measuring instruments. On the other hand, the alarm signal can be used as a trigger signal for judging the log of EMI noise that is detected before the output of it. + +When setting EMI-measuring systems, the following needs to be selected: sensing method (time- or frequency-domain), the range of frequency, the trigger level of target signal, etc. If the cause of EMI problems is estimated due to transient noise, time-domain measurement using oscilloscopes is recommended. If the cause of EMI problems seems to be due to wireless-related stationary or quasi-stationary sources, frequency-domain-based measurement using spectrum analysers, which generally have wideband and wide-dynamic ranges, is recommended. Some spectrum analysers allow the setting of a trigger line in the frequency domain, and the alarm signal from electrical equipment can be a trigger to start measurement. + +One difficulty in using a measuring system in actual environments is the setting of the measurement conditions. Namely, it is often difficult to estimate the level, frequency range, and duration of EMI noises beforehand. The receiving input range, trigger level, sampling time, buffer-length, etc., can be used as selective parameters for an oscilloscope, and the receiving input range, trigger level, frequency range, etc., can be used as selective parameters for a spectrum analyser. Here, the dead time for measuring systems tends to increase, if the buffer length of oscilloscopes, or the sweep times of spectrum analysers is increased. + +In storing detected data, time information (detection time) should also be stored to investigate the cause of EMI problems. Data transmission via networks can also be effective for checking the environment without having to go to the location. + +When setting up an EMI measuring system in a real environment, the electric power level should be checked to avoid unexpected power problems. In addition, E/O or O/E converters can be used when the cable connecting sensors and measuring instruments become too long (e.g., the measurements for lightning surges in real environments). + +### II.2 Flow chart for solving EMI problems of home networking equipment + +A flow chart for solving EMI problems of home networking equipment is shown in Figure II.1. + +![Flow chart for solving EMI problems of home networking equipment. The process starts with 'Recognizing problem of telecom equipment', followed by 'Sharing all information about the trouble' (which also receives input from 'Phenomenon, timing and period of occurrence, etc.'). It then enters a loop: 'Checking other possibilities' (Hardware failure, Software failure). If 'Yes', it goes to 'Solve the problem' and 'End'. If 'No', it goes to 'Checking installation' (Earthing and bonding, Cabling). If 'Bad', it goes to 'Fix the installation' and then to 'Problem solved?'. If 'Good', it goes to 'Checking compliance with EMC standard'. From 'Problem solved?', if 'No', it loops back to 'Checking installation'; if 'Yes', it goes to 'End'. The next step is 'Measuring the EM environment' (Who performs it, Measurement quantity, Measurement method, Measurement procedure), followed by 'Evaluating results and finding the cause of trouble' (Period of occurrence, Specifications of suspected equipment, Synchronization between trouble and disturbance, Other information).](28d75f39a24203712ee907b32cf0bbe5_img.jpg) + +``` + +graph TD + A[Recognizing problem of telecom equipment] --> B[Sharing all information about the trouble] + C[Phenomenon, timing and period of occurrence, etc.] --> B + B --> D{Checking other possibilities +- Hardware failure +- Software failure} + D -- Yes --> E[Solve the problem] + E --> F([End]) + D -- No --> G{Checking installation +- Earthing and bonding +- Cabling} + G -- Bad --> H[Fix the installation] + H --> I{Problem solved?} + I -- Yes --> J([End]) + I -- No --> G + G -- Good --> K[Checking compliance with EMC standard] + K --> L[Measuring the EM environment +- Who performs it +- Measurement quantity +- Measurement method +- Measurement procedure] + L --> M[Evaluating results and finding the cause of trouble +- Period of occurrence +- Specifications of suspected equipment (clock, etc.) +- Synchronization between trouble and disturbance +- Other information, e.g., installation of new equipment] + +``` + +Flow chart for solving EMI problems of home networking equipment. The process starts with 'Recognizing problem of telecom equipment', followed by 'Sharing all information about the trouble' (which also receives input from 'Phenomenon, timing and period of occurrence, etc.'). It then enters a loop: 'Checking other possibilities' (Hardware failure, Software failure). If 'Yes', it goes to 'Solve the problem' and 'End'. If 'No', it goes to 'Checking installation' (Earthing and bonding, Cabling). If 'Bad', it goes to 'Fix the installation' and then to 'Problem solved?'. If 'Good', it goes to 'Checking compliance with EMC standard'. From 'Problem solved?', if 'No', it loops back to 'Checking installation'; if 'Yes', it goes to 'End'. The next step is 'Measuring the EM environment' (Who performs it, Measurement quantity, Measurement method, Measurement procedure), followed by 'Evaluating results and finding the cause of trouble' (Period of occurrence, Specifications of suspected equipment, Synchronization between trouble and disturbance, Other information). + +K.92(12)\_FI1.1 + +Figure II.1 – Flow chart for solving EMI problems of home networking equipment + +# Bibliography + +- [b-CISPR 22] CISPR 22:2008, *Information technology equipment – Radio disturbance characteristics – Limits and methods of measurement.* + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|---------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.94-201205-I_PDF-E/raw.md b/marked/K/T-REC-K.94-201205-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..af892476021a9908b2d42942e1a4bb55a197a79d --- /dev/null +++ b/marked/K/T-REC-K.94-201205-I_PDF-E/raw.md @@ -0,0 +1,454 @@ + + +International Telecommunication Union + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.94** + +(05/2012) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Mutual disturbance test method for evaluating +performance degradation of converged terminal +devices** + +Recommendation ITU-T K.94 + +![ITU logo](6ed175c791b5e156d9c98a8dbcc3318c_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a red lightning bolt striking it, symbolizing telecommunications. To the right of the globe, the text "International Telecommunication Union" is written in a blue sans-serif font, with the acronym "ITU" in a larger, bold blue font above it. + +ITU logo + + + +# **Recommendation ITU-T K.94** + +# **Mutual disturbance test method for evaluating performance degradation of converged terminal devices** + +# **Summary** + +With the rapid progress of the telecommunication terminal technology, more and more converged devices are appearing on the market. As the modules of the converged devices are so close together, if the printed circuit board (PCB) is not designed properly, without adequate earthing, shielding or filtering, an electromagnetic compatibility (EMC) disturbance can occur between the modules. Recommendation ITU-T K.94 analyses the EMC disturbance between different modules in converged terminal devices and defines a conducted test method. This mutual-disturbance test can be used as one of the immunity test items listed in Recommendation ITU-T K.34 and Recommendation ITU-T K.48 to determine the level of performance degradation. + +## **History** + +| Edition | Recommendation | Approval | Study Group | +|---------|----------------|------------|-------------| +| 1.0 | ITU-T K.94 | 2012-05-29 | 5 | + +# FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2012 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|--------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 1 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Basic test configuration ..... | 2 | +| 5.1 Test chamber ..... | 2 | +| 5.2 Generic test set-up ..... | 2 | +| 6 Generic test procedure..... | 3 | +| 7 Test procedure for typical converged devices ..... | 3 | +| 7.1 GSM/Wireless LAN converged device ..... | 4 | +| 7.2 UMTS/Wireless LAN converged device..... | 5 | +| 7.3 CDMA/Wireless LAN converged device..... | 6 | +| 7.4 GSM/CDMA converged device ..... | 8 | +| Annex A – Wireless LAN receiver sensitivity test methodology ..... | 10 | +| A.1 General description..... | 10 | +| A.2 Unicast test packets ..... | 10 | +| A.3 Frequency channels and data rates ..... | 10 | +| A.4 Test procedure ..... | 10 | +| Annex B – CDMA receiver sensitivity test methodology ..... | 11 | +| B.1 General description..... | 11 | +| B.2 Network parameters and test channels ..... | 11 | +| B.3 Test procedure ..... | 11 | +| Bibliography..... | 12 | + +# **Introduction** + +With the rapid progress of the telecommunication terminal technology, more and more converged devices are appearing on the market. Converged devices usually contain two or more modules which can transmit at the same time, for example: GSM/Wireless LAN dual mode terminal, WCDMA/Wireless LAN dual mode terminal, CDMA/Wireless LAN dual mode terminal, GSM/CDMA dual mode terminal. As the two modules are physically close to each other, if the PCB is not designed properly, without adequate earthing, shielding or filtering, an EMC disturbance could occur between the modules. + +In order to limit the EMC disturbance between these modules, this Recommendation defines a test method that can be used as one of the EMC immunity test items on a converged device. + +## Mutual disturbance test method for evaluating performance degradation of converged terminal devices + +# 1 Scope + +This Recommendation analyses the electromagnetic compatibility (EMC) disturbance between different modules in converged terminal devices and defines a conducted test method. As more and more converged devices appear on the market, this Recommendation will help the industry to analyse and reduce such disturbance. Furthermore, this mutual-disturbance test can be used as one of the immunity test items listed in [ITU-T K.34] and [ITU-T K.48] to determine the level of performance degradation. + +This Recommendation only covers the EMC mutual-disturbance between the different modules in converged devices. Examples of such devices include: GSM/Wireless LAN converged devices, WCDMA/Wireless LAN converged devices, CDMA/Wireless LAN converged devices and GSM/CDMA converged devices. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.34] Recommendation ITU-T K.34 (2003), *Classification of electromagnetic environmental conditions for telecommunication equipment – Basic EMC Recommendation*. +- [ITU-T K.48] Recommendation ITU-T K.48 (2006), *EMC requirements for telecommunication equipment – Product family Recommendation*. +- [ETSI TS 134 114] ETSI TS 134 114 (2008), *Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); User Equipment (UE)/Mobile Station (MS) Over The Air (OTA) antenna performance; Conformance testing (3GPP TS 34.114 version 7.0.0 Release 7)*. +<[http://www.etsi.org/deliver/etsi\\_ts/134100\\_134199/134114/07.00.00\\_60/ts\\_134114v070000p.pdf](http://www.etsi.org/deliver/etsi_ts/134100_134199/134114/07.00.00_60/ts_134114v070000p.pdf)> + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +None. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 converged device:** A device containing two or more transmitters that can operate simultaneously. Examples of transmitter types are GSM, wireless LAN, WCDMA and CDMA. + +**3.2.2 minimum forward-link power:** The minimum power of receiver BER (or FER) arriving to a certain level by the transmission of a base station. + +**3.2.3 standby mode:** One mode of the converged device. In this mode, the module is registered to the network and can respond to a request from the network. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|-------------------------------------------| +| ACK | Acknowledge | +| AP | Access Point | +| BER | Bit Error Ratio | +| CDMA | Code Division Multiple Access | +| EMC | Electromagnetic Compatibility | +| EUT | Equipment Under Test | +| FER | Frame Error Rate | +| FRR | Frame Reception Rate | +| GSM | Global System for Mobile communications | +| LAN | Local Area Network | +| NID | Network Identification | +| PC | Personal Computer | +| PCB | Printed Circuit Board | +| RBER | Residual Bit Error Ratio | +| RF | Radio Frequency | +| Rx | Receiver | +| SID | System Identification | +| UMTS | Universal Mobile Telecommunication System | +| WCDMA | Wideband Code Division Multiple Access | + +# **5 Basic test configuration** + +## **5.1 Test chamber** + +To avoid other disturbances, all the test cases should be performed in a shielded chamber as defined in clause 5.2. + +## **5.2 Generic test set-up** + +An outline of the test set-up is shown in Figure 1. The converged device is put into a shielded chamber, while all the test equipment is outside of the chamber. To measure the conducted disturbance, the converged device modules should be modified to have a connection to a base station emulator via RF cables entering the shielded chamber. There will be two or more base station emulators depending on how many modules the converged device has. + +![Figure 1 – Test set-up illustration of the converged devices. The diagram shows a central 'Shielded chamber' containing a 'Converged device under test'. Two 'Base station emulator' units are positioned outside the chamber. Each emulator is connected to the device inside the chamber via an 'RF cable'. The label 'K.94(12)F_01' is in the bottom right corner.](ebff22fb5dd6f50a90e44dca0f82f285_img.jpg) + +Figure 1 – Test set-up illustration of the converged devices. The diagram shows a central 'Shielded chamber' containing a 'Converged device under test'. Two 'Base station emulator' units are positioned outside the chamber. Each emulator is connected to the device inside the chamber via an 'RF cable'. The label 'K.94(12)F\_01' is in the bottom right corner. + +**Figure 1 – Test set-up illustration of the converged devices** + +# 6 Generic test procedure + +Assuming that the converged device has only two modules – module A and module B – the following procedures are used to determine the disturbance from module B to module A. The disturbance from module A to module B can be determined using the same procedure. + +- 1) To perform this test, the converged device should be modified to include a test port connection for both module A and module B. +- 2) Put the converged device in the shielded chamber to minimize external disturbances. Only the converged device should be put in the shielded chamber; all the testing equipment should be put outside. +- 3) Connect module A with its network emulator using an RF cable. Before the test, the cable loss between the converged device and its network emulator should be measured and later used to compensate the test result. +- 4) Measure the conducted sensitivity of all the channels of module A according to the method of different product standards or Annex A of this Recommendation. During the test, module B should be set to the standby mode if module A has too many channels. It is acceptable if the separation between the two test channels is lower than 500 kHz. +- 5) Record the conducted sensitivity of each channel, as $SEN_{ori-x}$ , where x represents the channel number. +- 6) Connect module B with its network emulator at the lowest channel; the test settings should conform to the method of different product standards or Annex A of this Recommendation. During the following test, module B should maintain the maximum power output condition. +- 7) Measure the conducted sensitivity of module A as specified in step 4) again. Record the conducted sensitivity of each channel as $SEN_{dis-x}$ . +- 8) The performance degradation of module A at channel x can be expressed as $SEN_{deg-x} = SEN_{dis-x} - SEN_{ori-x}$ . +- 9) Connect module B with its network emulator at the middle channel and high channel separately. Perform steps 6) to 8) again and determine the disturbance from module B at the middle channel and high channel. +- 10) Record all the performance degradation results. + +# 7 Test procedure for typical converged devices + +Test procedures for some typical converged devices are given in this clause. For those converged devices not listed here, the generic method in clause 6 applies. + +## 7.1 GSM/Wireless LAN converged device + +### 7.1.1 General description + +In this clause, the GSM module is module A and the wireless LAN module is module B. + +### 7.1.2 GSM performance degradation test procedure + +The following procedures are used to evaluate the GSM performance degradation in presence with the Wireless LAN module: + +- 1) To perform this test, the GSM/wireless LAN converged device should be modified to include the test port connection for both module A and module B. +- 2) Put the converged device in the shielded chamber to minimize external disturbances. Only the converged device should be put in the shielded chamber; all the testing equipment should be put outside. +- 3) Connect module A with its network emulator using an RF cable. Before the test, the cable loss between the converged device and its network emulator should be measured and later used to compensate the test result. +- 4) Measure the conducted sensitivity of all the channels of module A according to [ETSI TS 134 114]. Measure the Class II residual BER (RBER) on module A. The number of frames observed shall be consistent with a 95% confidence level, but may be limited to 135 frames maximum. The measured RBER must not exceed 2.44% during the sensitivity search. During the test, module B should be set to the standby mode. If module A has too many channels, it is acceptable if the separation between the two test channels is lower than 500 kHz. +- 5) Record the conducted sensitivity of each channel as $SEN_{ori-x}$ , where x represents the channel number. +- 6) Connect module B with its network emulator at the lowest channel; the test settings should conform to Annex A of this Recommendation. During the following test, module B should maintain the maximum power output condition. +- 7) Measure the conducted sensitivity of module A as specified in step 4) again. Record the conducted sensitivity of each channel as $SEN_{dis-x}$ . +- 8) The performance degradation of module A at channel x can be expressed as $SEN_{deg-x} = SEN_{dis-x} - SEN_{ori-x}$ . +- 9) Connect module B with its network emulator at the middle channel and high channel separately. Perform steps 6) to 8) again and determine the disturbance from module B at the middle channel and high channel. +- 10) Record all the performance degradation results. + +### 7.1.3 Wireless LAN performance degradation test procedure + +The following procedures are used to evaluate the wireless LAN performance degradation in presence with the GSM module: + +- 1) To perform this test, the converged device should be modified to include the test port connection for both module A and module B. +- 2) Put the converged device in the shielded chamber to minimize external disturbances. Only the converged device should be put in the shielded chamber; all the testing equipment should be put outside. +- 3) Connect module B with its network emulator using an RF cable. Before the test, the cable loss between the converged device and its network emulator should be measured and later used to compensate the test result. + +- 4) Measure the conducted sensitivity of all the channels of module B according to Annex A of this Recommendation. During the test, module A should be set to the standby mode. +- 5) Record the conducted sensitivity of each channel as $SEN_{ori-x}$ , where x represents the channel number. +- 6) Connect module A with its network emulator at the lowest channel; the test settings should conform to [ETSI TS 134 114]. During the following test, module A should maintain the maximum power output condition. +- 7) Measure the conducted sensitivity of module B as specified in step 4) again. Record the conducted sensitivity of each channel as $SEN_{dis-x}$ . +- 8) The performance degradation of module B at channel x can be expressed as $SEN_{deg-x} = SEN_{dis-x} - SEN_{ori-x}$ . +- 9) Connect module A with its network emulator at the middle channel and high channel separately. Perform steps 6) to 8) again and determine the disturbance from module A at the middle channel and high channel. +- 10) Record all the performance degradation results. + +## 7.2 UMTS/Wireless LAN converged device + +### 7.2.1 General description + +In this clause, the UMTS module is named as module A and the wireless LAN module is named as module B. For simplicity, only UMTS BAND I is used in this example. + +### 7.2.2 UMTS performance degradation test procedure + +The following procedures are used to evaluate the UMTS performance degradation in presence with the Wireless LAN module: + +- 1) To perform this test, the UMTS/wireless LAN converged device should be modified to include the test port connection for both module A and module B. +- 2) Put the converged device in the shielded chamber to minimize external disturbances. Only the converged device should be put in the shielded chamber; all the testing equipment should be put outside. +- 3) Connect module A with its network emulator using an RF cable. Before the test, the cable loss between the converged device and its network emulator should be measured and later used to compensate the test result. +- 4) Measure the conducted sensitivity of all the channels of module A according to [ETSI TS 134 114]. Measure the BER on module A; the number of frames observed shall be consistent with a 95% confidence level. The measured BER must not exceed 1% during the sensitivity search. During the test, module B should be set to the standby mode. +- 5) Record the conducted sensitivity of each channel as $SEN_{ori-x}$ , where x represents the channel number. +- 6) Connect module B with its network emulator at the lowest channel; the test settings should conform to Annex A of this Recommendation. During the following test, module B should maintain the maximum power output condition. +- 7) Measure the conducted sensitivity of module A as specified in step 4) again. Record the conducted sensitivity of each channel as $SEN_{dis-x}$ . +- 8) The performance degradation of module A at channel x can be expressed as $SEN_{deg-x} = SEN_{dis-x} - SEN_{ori-x}$ . + +- 9) Connect module B with its network emulator at the middle channel and high channel separately. Perform steps 6) to 8) again and determine the disturbance from module B at the middle channel and high channel. +- 10) Record all the performance degradation results. + +### **7.2.3 Wireless LAN performance degradation test procedure** + +The following procedures are used to evaluate the Wireless LAN performance degradation in presence with the UMTS module: + +- 1) To perform this test, the wireless LAN/UMTS converged device should be modified to include the test port connection for both module A and module B. +- 2) Put the converged device in the shielded chamber to minimize external disturbances. Only the converged device should be put in the shielded chamber; all the testing equipment should be put outside. +- 3) Connect module B with its network emulator using an RF cable. Before the test, the cable loss between the converged device and its network emulator should be measured and later used to compensate the test result. +- 4) Measure the conducted sensitivity of all the channels of module B according to Annex A of this Recommendation. During the test, module A should be set to the standby mode. +- 5) Record the conducted sensitivity of each channel as $SEN_{ori-x}$ , where x represents the channel number. +- 6) Connect module A with its network emulator at the lowest channel; the test settings should comply with [ETSI TS 134 114]. During the following test, module A should maintain the maximum power output condition. +- 7) Measure the conducted sensitivity of module B as specified in step 4) again. Record the conducted sensitivity of each test channel as $SEN_{dis-x}$ . +- 8) The performance degradation of module B at channel x can be expressed as $SEN_{deg-x} = SEN_{dis-x} - SEN_{ori-x}$ . +- 9) Connect module A with its network emulator at the middle channel and high channel separately. Perform steps 6) to 8) again and determine the disturbance from module A at the middle channel and high channel. +- 10) Record all the performance degradation results. + +## **7.3 CDMA/Wireless LAN converged device** + +### **7.3.1 General description** + +In this clause, the CDMA module is named as module A and the wireless LAN module is named as module B. + +### **7.3.2 CDMA performance degradation test procedure** + +The following procedures are used to evaluate the CDMA performance degradation in presence with the wireless LAN module: + +- 1) To perform this test, the CDMA/wireless LAN converged device should be modified to include the test port connection for both module A and module B. +- 2) Put the converged device in the shielded chamber to minimize external disturbances. Only the converged device should be put in the shielded chamber; all the testing equipment should be put outside. + +- 3) Connect module A with its network emulator using an RF cable. Before the test, the cable loss between the converged device and its network emulator should be measured and later used to compensate the test result. +- 4) Measure the conducted sensitivity of all the channels of module A according to Annex B. Measure the FER on module A; the number of frames observed shall be consistent with a 95% confidence level. The measured FER must not exceed 1.2% during the sensitivity search. During the test, module B should be set to the standby mode. +- 5) Record the conducted sensitivity of each channel as $SEN_{ori-x}$ , where x represents the channel number. +- 6) Connect module B with its network emulator at the lowest channel; the test settings should conform to Annex A of this Recommendation. During the following test, module B should maintain the maximum power output condition. +- 7) Measure the conducted sensitivity of module A as specified in step 4) again. Record the conducted sensitivity of each test channel as $SEN_{dis-x}$ . +- 8) The performance degradation of module A at channel x can be expressed as $SEN_{deg-x} = SEN_{dis-x} - SEN_{ori-x}$ . +- 9) Connect module B with its network emulator at the middle channel and high channel separately. Perform steps 6) to 8) again and determine the disturbance from module B at the middle channel and high channel. +- 10) Record all the performance degradation results. + +### 7.3.3 Wireless LAN performance degradation test procedure + +The following procedures are used to evaluate the Wireless LAN performance degradation in presence with the CDMA module: + +- 1) To perform this test, the Wireless LAN/CDMA converged device should be modified to include the conducted test port for both module A and module B. +- 2) Put the converged device in the shielded chamber to minimize external disturbances. Only the converged device should be put in the shielded chamber; all the testing equipment should be put outside. +- 3) Connect module B with its network emulator using an RF cable. Before the test, the cable loss between the converged device and its network emulator should be measured and later used to compensate the test result. +- 4) Measure the conducted sensitivity of all the channels of module B according to Annex A of this Recommendation. During the test, the module A should be set to the standby mode. +- 5) Record the conducted sensitivity of each channel as $SEN_{ori-x}$ , where x represents the channel number. +- 6) Connect module A with its network emulator at the lowest channel; the test parameters should comply with Annex B. During the following test, the module A should maintain the maximum power output condition. +- 7) Measure the conducted sensitivity of module B as specified in step 4) again. Record the conducted sensitivity of each channel as $SEN_{dis-x}$ . +- 8) The performance degradation of module B at channel x can be expressed as $SEN_{deg-x} = SEN_{dis-x} - SEN_{ori-x}$ . +- 9) Connect module A with its network emulator at the middle channel and high channel separately. Perform steps 6) to 8) again and determine the disturbance from module A at the middle channel and high channel. +- 10) Record all the performance degradation results. + +## 7.4 GSM/CDMA converged device + +### 7.4.1 General + +In this clause, the GSM module is named as module A and the CDMA module is named as module B. + +### 7.4.2 GSM performance degradation test procedure + +The following procedures are used to evaluate the GSM performance degradation in presence with the CDMA module: + +- 1) To perform this test, the GSM/CDMA converged device should be modified to include the conducted test port for both module A and module B. +- 2) Put the converged device in the shielded chamber to minimize external disturbances. Only the converged device should be put in the shielded chamber; all the testing equipment should be put outside. +- 3) Connect module A with its network emulator using an RF cable. Before the test, the cable loss between the converged device and its network emulator should be measured and later used to compensate the test result. +- 4) Measure the conducted sensitivity of all the channels of module A according to [ETSI TS 134 114]. Measure the Class II residual BER (RBER) on module A; the number of frames observed shall be consistent with a 95% confidence level, but may be limited to 135 frames maximum. The measured RBER must not exceed 2.44% during the sensitivity search. During the test, module B should be set to the standby mode. If module A has too many channels, it is acceptable if the separation between the two test channels is lower than 500 kHz. +- 5) Record the conducted sensitivity of each channel as $SEN_{ori-x}$ , where x represents the channel number. +- 6) Connect module B with its network emulator at the lowest channel; the test settings should conform to Annex B of this Recommendation. During the following test, module B should maintain the maximum power output condition. +- 7) Measure the conducted sensitivity of module A as specified in step 4) again, Record the conducted sensitivity of each channel as $SEN_{dis-x}$ . +- 8) The performance degradation of module A at channel x can be expressed as $SEN_{deg-x} = SEN_{dis-x} - SEN_{ori-x}$ . +- 9) Connect module B with its network emulator at the middle channel and high channel separately. Perform steps 6) to 8) again and determine the disturbance from module B at the middle channel and high channel. +- 10) Record all the performance degradation results. + +### 7.4.3 CDMA performance degradation test procedure + +The following procedures are used to evaluate the CDMA performance degradation in presence with the GSM module: + +- 1) To perform this test, the CDMA/GSM converged device should be modified to include the conducted test port for both module A and module B. +- 2) Put the converged device in the shielded chamber to minimize external disturbances. Only the converged device should be put in the shielded chamber; all the testing equipment should be put outside. + +- 3) Connect module B with its network emulator using an RF cable. Before the test, the cable loss between the converged device and its network emulator should be measured and later used to compensate the test result. +- 4) Measure the conducted sensitivity of all channels of module B according to Annex B. Measure the FER on module B; the number of frames observed shall be consistent with a 95% confidence level. The measured FER must not exceed 1.2% during the sensitivity search. During the test, module A should be set to the standby mode. +- 5) Record the conducted sensitivity of each channel as $SEN_{ori-x}$ , where x represents the channel number. +- 6) Connect module A with its network emulator at the lowest channel; the test settings should conform to [ETSI TS 134 114]. During the following test, module A should maintain the maximum power output condition. +- 7) Measure the conducted sensitivity of module B as specified in step 4) again. Record the conducted sensitivity of each channel as $SEN_{dis-x}$ . +- 8) The performance degradation of module B at channel x can be expressed as $SEN_{deg-x} = SEN_{dis-x} - SEN_{ori-x}$ . +- 9) Connect module A with its network emulator at the middle channel and high channel separately. Perform steps 6) to 8) again and determine the disturbance from module A at the middle channel and high channel. +- 10) Record all the performance degradation results. + +# Annex A + +## Wireless LAN receiver sensitivity test methodology + +(This annex forms an integral part of this Recommendation.) + +### A.1 General description + +The method used to determine the receiver sensitivity of Wireless LAN is based upon the Wireless LAN test set equipment, which will simulate the test AP. The test AP reports the number of ACK control frames per second being sent by the EUT in response to continuous unicast data packets being sent from it. The output transmitted power from the test AP needs to be calibrated before this test. + +### A.2 Unicast test packets + +The unicast test data packets shall be 200 frame bytes at a rate of 50 frames a second, to approximate a voice data stream. + +### A.3 Frequency channels and data rates + +On each frequency channel, receiver sensitivity shall be measured at the following data rate, which is the highest data rate it supports: + +IEEE 802.11b: 11 Mbps + +IEEE 802.11g: 54 Mbps + +IEEE 802.11a: 54 Mbps + +### A.4 Test procedure + +The test method to determine the receiver sensitivity conforms to the following procedure. + +- 1) The AP attenuator in the Wireless LAN test set, which is the transmit attenuator, is set such that the signal received at the EUT is about 10 dB higher than the conducted sensitivity threshold. +- 2) The RX attenuator, in the Wireless LAN Test Set is set such that the received signal level from the EUT at the input of the Wireless LAN receiver is at least 10 dB higher than the conducted sensitivity of the Wireless LAN receiver. +- 3) The test AP is set up to transmit on the desired channel, modulation and data rate. +- 4) Connect the EUT with the AP. +- 5) The test AP is set to continuously transmit unicast data packets to the EUT. +- 6) The EUT responds to the received unicast data packets with an ACK control frame. +- 7) The Wireless LAN test set reports the reception of the ACK control frames to the control PC. +- 8) The control PC counts the number of data frames and the number of ACK control frames received over a time period needed to receive 1000 data frames and the corresponding ACKs. The FRR is computed as (# of ACKs received / # data frames transmitted). +- 9) Increase the AP attenuator, until the FRR reduces to the point where a 1 dB increase causes the FRR to be less than 90%. +- 10) Record the power at the EUT antenna port as the minimum forward-link power. +- 11) Repeat steps 1) to 10) for each required channel, modulation and data rate. + +# Annex B + +## CDMA receiver sensitivity test methodology + +(This annex forms an integral part of this Recommendation.) + +### B.1 General description + +Receiver sensitivity measurements shall be performed using the base station emulator to determine the EUT's receiver sensitivity by reporting the minimum forward-link power resulting in a frame error rate (FER) of 1.2% with 95% confidence. + +### B.2 Network parameters and test channels + +- SID and NID are set according to the network parameters. +- Service option is set to 2 or 55. +- Forward-link power: as needed to maintain 0% FER. +- Power control: closed loop and always up. + +### B.3 Test procedure + +The test method to determine the receiver sensitivity conforms to the following procedure. + +- 1) Adjust the output power of the network emulator so that the signal received at the EUT is about 10 dB higher than the conducted sensitivity threshold. +- 2) The network emulator is set up to transmit on the desired channel and data rate. +- 3) The EUT connects with the network emulator by a cable. +- 4) The number of frames observed shall be consistent with a 95% confidence level but may be limited to 1000 frames maximum at 1.2% FER. +- 5) The forward-link power step size shall be no more than 0.5 dB when the RF power level is near the CDMA sensitivity level. +- 6) Record the power at the EUT antenna port as the minimum forward-link power. +- 7) Repeat steps 1) to 6) for each required channel. + +# Bibliography + +- [b-IEEE 802.11a] IEEE 802.11a-1999, *IEEE Standard for Telecommunications and Information Exchange Between Systems – LAN/MAN Specific Requirements – Part 11: Wireless Medium Access Control (MAC) and physical layer (PHY) specifications: High Speed Physical Layer in the 5 GHz band.* +- [b-IEEE 802.11b] IEEE 802.11b-1999, *IEEE Standard for Information Technology – Telecommunications and information exchange between systems – Local and Metropolitan networks – Specific requirements – Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Higher Speed Physical Layer (PHY) Extension in the 2.4 GHz band.* +- [b-IEEE 802.11g] IEEE 802.11g-2003, *IEEE Standard for Information technology – Local and metropolitan area networks – Specific requirements – Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications: Further Higher Data Rate Extension in the 2.4 GHz Band.* + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|---------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and 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It features a blue globe with white lines representing latitude and longitude, and the letters 'ITU' in a bold, blue, sans-serif font superimposed on the globe. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +## **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|--------------------------------------------------------|--------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.100 + +# Optical fibre cables for duct and tunnel application + +## Summary + +Recommendation ITU-T L.100 describes characteristics, construction, test methods, and performance criteria of optical fibre cables installed by pulling method for duct and tunnel application. Note that Recommendation ITU-T L.10, Ed 3.0, was redesignated as ITU-T L.100/L.10, Ed 3.0, in February 2016. + +First, in order to demonstrate the sufficient performance of an optical fibre cable, the characteristics that a cable should possess are described in this Recommendation. Then, the methods of examining whether a cable has the required characteristics are described in this Recommendation. Therein, detailed performance criteria for a cable are recommended. + +Recommended technical requirements are detailed by reference to IEC 60794-3-11 on outdoor optical fibre cables for duct, directly buried, and lashed aerial applications. Changes and additions to these requirements suitable to the duct and tunnel cable applications are recommended herein. + +Required conditions may differ from the installation environment. Therefore, instances where agreement on detailed conditions should be determined between customer and manufacturer are stated. + +This version of Recommendation ITU-T L.100 adds the electrical continuity test for continuous metallic elements. Scope, References, fibre dimensions, Annex A and Bibliography are also updated. + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|------------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.10 | 1988-11-25 | | 11.1002/1000/1414 | +| 2.0 | ITU-T L.10 | 2002-12-22 | 6 | 11.1002/1000/6134 | +| 3.0 | ITU-T L.100/L.10 | 2015-08-13 | 15 | 11.1002/1000/12532 | +| 4.0 | ITU-T L.100/L.10 | 2021-05-29 | 15 | 11.1002/1000/14631 | +| 5.0 | ITU-T L.100 | 2024-01-13 | 15 | 11.1002/1000/15812 | + +## Keywords + +Duct, environmental condition, mechanical characteristics, optical fibre cable, test method, tunnel. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2024 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|-----|----------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 4 | +| 3.1 | Terms defined elsewhere ..... | 4 | +| 3.2 | Terms defined in this Recommendation..... | 4 | +| 4 | Abbreviations and acronyms ..... | 4 | +| 5 | Conventions ..... | 4 | +| 6 | Characteristics of optical fibres and cables ..... | 4 | +| 6.1 | Optical fibre characteristics ..... | 4 | +| 6.2 | Mechanical characteristics..... | 5 | +| 6.3 | Environmental characteristics ..... | 7 | +| 6.4 | Fire safety ..... | 10 | +| 6.6 | Electrical characteristics ..... | 11 | +| 7 | Cable construction ..... | 11 | +| 7.1 | Fibre coatings ..... | 11 | +| 7.2 | Cable elements..... | 12 | +| 7.3 | Sheath and jacket..... | 15 | +| 7.4 | Armour ..... | 16 | +| 7.5 | Identification of cable..... | 16 | +| 7.6 | Cable sealing ..... | 16 | +| 7.7 | Considerations for duct installation..... | 16 | +| | Annex A – Test methods..... | 17 | +| A.1 | Standard test criteria ..... | 20 | +| A.2 | Test methods for cable elements ..... | 21 | +| A.3 | Test methods for mechanical characteristics of the cable ..... | 23 | +| A.4 | Test methods for environmental characteristics ..... | 27 | +| A.5 | Test methods for biotic characteristics ..... | 31 | +| A.6 | Test methods for electrical characteristics ..... | 31 | +| | Bibliography..... | 33 | + + + +# Recommendation ITU-T L.100 + +## Optical fibre cables for duct and tunnel application + +# 1 Scope + +This Recommendation: + +- refers to single-mode optical fibre cables installed by the pulling method to be used for telecommunication networks in ducts and tunnels; +- recommends that optical fibre dimensional and transmission characteristics should comply with one or more of [ITU-T G.652], [ITU-T G.653], [ITU-T G.654], [ITU-T G.655], [ITU-T G.656], [ITU-T G.657] and [IEC 60793-2-50]; +- deals with mechanical, environmental, and electrical characteristics of optical fibre cables that are installed in the ducts or tunnels; +- refers to the technical specifications of [IEC 60794-3-11] as applicable to the concerned optical fibre cables; +- recommends performance criteria for those tests that are relevant to the duct and the tunnel application space. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T G.650.1] Recommendation ITU-T G.650.1 (2024), *Definitions and test methods for linear, deterministic attributes of single-mode fibre and cable*. +- [ITU-T G.650.2] Recommendation ITU-T G.650.2 (2015), *Definitions and test methods for statistical and non-linear related attributes of single-mode fibre and cable*. +- [ITU-T G.650.3] Recommendation ITU-T G.650.3 (2017), *Test methods for installed single-mode optical fibre cable links*. +- [ITU-T G.652] Recommendation ITU-T G.652 (2016), *Characteristics of a single-mode optical fibre and cable*. +- [ITU-T G.653] Recommendation ITU-T G.653 (2010), *Characteristics of a dispersion-shifted, single-mode optical fibre and cable*. +- [ITU-T G.654] Recommendation ITU-T G.654 (2020), *Characteristics of a cut-off shifted single-mode optical fibre and cable*. +- [ITU-T G.655] Recommendation ITU-T G.655 (2009), *Characteristics of a non-zero dispersion-shifted single-mode optical fibre and cable*. +- [ITU-T G.656] Recommendation ITU-T G.656 (2010), *Characteristics of a fibre and cable with non-zero dispersion for wideband optical transport*. +- [ITU-T G.657] Recommendation ITU-T G.657 (2016), *Characteristics of a bending-loss insensitive single-mode optical fibre and cable*. + +- [ITU-T K.29] Recommendation ITU-T K.29 (1992), *Coordinated protection schemes for telecommunication cables below ground*. +- [ITU-T K.47] Recommendation ITU-T K.47 (2012), *Protection of telecommunication lines against direct lightning flashes*. +- [ITU-T L.108] Recommendation ITU-T L.108 (2018), *Optical fibre cable elements for microduct blowing-installation application*. +- [ITU-T L.126] Recommendation ITU-T L.126/L.27 (1996), *Method for estimating the concentration of hydrogen in optical fibre cables*. +- [ITU-T L.161] Recommendation ITU-T L.161/L.46 (2000), *Protection of telecommunication cables and plant from biological attack*. +- [IEC 60304] IEC 60304:1982, *Standard colours for insulation for low-frequency cables and wires*. +- [IEC 60331-25] IEC 60331-25:1999, *Tests for electric cables under fire conditions – Circuit integrity – Part 25: Procedures and requirements – Optical fibre cables*. +- [IEC 60332-1-2] IEC 60332-1-2:2004, *Tests on electric and optical fibre cables under fire conditions – Part 1-2: Test for vertical flame propagation for a single insulated wire or cable – Procedure for 1 kW pre-mixed flame*. +- [IEC 60332-3-24] IEC 60332-3-24:2018, *Tests on electric and optical fibre cables under fire conditions – Part 3-24: Test for vertical flame spread of vertically-mounted bunched wires or cables – Category C*. +- [IEC 60708] IEC 60708:2005, *Low-frequency cables with polyolefin insulation and moisture barrier polyolefin sheath*. +- [IEC 60754-1] IEC 60754-1:2011+AMD1:2019 CSV Consolidated version, *Test on gases evolved during combustion of materials from cables – Part 1: Determination of the halogen acid gas content*. +- [IEC 60754-2] IEC 60754-2:2011+AMD1:2019 CSV Consolidated version, *Test on gases evolved during combustion of materials from cables – Part 2: Determination of acidity (by pH measurement) and conductivity*. +- [IEC 60793-1-21] IEC 60793-1-21:2001, *Optical fibres – Part 1-21: Measurement methods and test procedures – Coating geometry*. +- [IEC 60793-1-32] IEC 60793-1-32:2018, *Optical fibres – Part 1-32: Measurement methods and test procedures – Coating strippability*. +- [IEC 60793-1-40] IEC 60793-1-40:2019, *Optical fibres – Part 1-40: Attenuation measurement methods*. +- [IEC 60793-2-50] IEC 60793-2-50:2018, *Optical fibres – Part 2-50: Product specifications – Sectional specification for class B single-mode fibres*. +- [IEC 60794-1-1] IEC 60794-1-1:2023, *Optical fibre cables – Part 1-1: Generic specification – General*. +- [IEC 60794-1-2] IEC 60794-1-2:2021, *Optical fibre cables – Part 1-2: Generic specification – Basic optical cable test procedures – General guidance*. +- [IEC 60794-1-21] IEC 60794-1-21:2015+AMD1:2020 CSV Consolidated version, *Optical fibre cables – Part 1-21: Generic specification – Basic optical cable test procedures – Mechanical tests methods*. + +- [IEC 60794-1-23] IEC 60794-1-23:2019, Optical fibre cables – *Part 1-23: Generic specification – Basic optical cable test procedures – Cable element test methods.* +- [IEC 60794-1-31] IEC 60794-1-31:2021, Optical fibre cables – *Part 1-31: Generic specification – Optical cable elements – Optical fibre ribbon.* +- [IEC 60794-1-215] IEC 60794-1-215:2020, Optical fibre cables – *Part 1-215: Generic specification – Basic optical cable test procedures – Environmental test methods – Cable external freezing test, Method F15.* +- [IEC 60794-1-219] IEC 60794-1-219:2021, Optical fibre cables – *Part 1-219: Generic specification – Basic optical cable test procedures – Material compatibility test, method F19.* +- [IEC 60794-1-310] IEC 60794-1-310:2022, Optical fibre cables – *Part 1-310: Generic specification – Basic optical cable test procedures – Cable element test methods – Strippability, method G10.* +- [IEC 60794-1-403] IEC 60794-1-403:2021, Optical fibre cables – *Part 1-403: Generic specification – Basic optical cable test procedures – Electrical test methods – Electrical continuity test of cable metallic elements, method H3.* +- [IEC 60794-3] IEC 60794-3:2022, *Optical fibre cables – Part 3: Outdoor cables – Sectional specification.* +- [IEC 60794-3-11] IEC 60794-3-11:2010, *Optical fibre cables – Part 3-11: Outdoor cables – Product specification for duct, directly buried, and lashed aerial single-mode optical fibre telecommunication cables.* +- [IEC 60811-202] IEC 60811-202:2012+AMD1:2017+AMD2:2023 CSV Consolidated version, *Electric and optical fibre cables – Test methods for non-metallic materials – Part 202: General tests – Measurement of thickness of non-metallic sheath.* +- [IEC 60811-203] IEC 60811-203:2012, *Electric and optical fibre cables – Test methods for non-metallic materials – Part 203: General tests – Measurement of overall dimensions.* +- [IEC 60811-501] IEC 60811-501:2012+AMD1:2018+AMD2:2023 CSV Consolidated version, *Electric and optical fibre cables – Test methods for non-metallic materials – Part 501: Mechanical tests – Tests for determining the mechanical properties of insulating and sheathing compounds.* +- [IEC 61034-1] IEC 61034-1:2005+AMD1:2013+AMD2:2019 CSV Consolidated version, *Measurement of smoke density of cables burning under defined conditions – Part 1: Test apparatus.* +- [IEC 61034-2] IEC 61034-2:2005/AMD2:2019, Amendment 2 – *Measurement of smoke density of cables burning under defined conditions – Part 2: Test procedure and requirements.* +- [IEC 61196-1-313] IEC 61196-1-313:2009, *Coaxial communication cables –Part 1-313: Mechanical test methods – Adhesion of dielectric and sheath.* +- [ISO 11357-6] ISO 11357-6:2018, *Plastics – Differential scanning calorimetry (DSC) – Part 6: Determination of oxidation induction time (isothermal OIT) and oxidation induction temperature (dynamic OIT).* + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +For the purpose of this Recommendation, the definitions given in [ITU-T G.650.1], [ITU-T G.650.2], [ITU-T G.650.3] and [IEC 60794-1-1] apply. + +Other terms used, particularly in referencing IEC test procedures and specifications, are per [IEC 60794-1-1] and other IEC specifications specifically referenced. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 attenuation and attenuation coefficient:** Attenuation is used, herein, for brevity and convenience, with the understanding that values on a per length basis – dB/km – are, most correctly, attenuation coefficient. + +**3.2.2 cable weight (W):** Force (N) exerted from the weight of 1 km of the cable that is suspended vertically. + +**3.2.3 jacket:** One or more polymer coverings comprising the main protection of the fibre cable as part of a sheath; inner jackets or outer jackets may be used, as necessary. + +**3.2.4 sheath:** An assembly of cable elements surrounding and protecting the fibre core; including, but not limited to, jacket(s), strength member(s), armour(s), moisture barrier(s), etc. as necessary. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|----------------------------------|--------------------------------------------------------------------------------------------------------| +| BoL | Beginning of Life, as applied to cable testing and criteria | +| d | Outer diameter, as of a cable, core tube, or other element described in the usage (see clause 6.2.3.1) | +| DS | Detailed Specification | +| EoL | End of Life, as applied to cable testing and criteria | +| L L | Long-term, or residual, load rating of a cable | +| L S or L M | Tensile rating of a cable | +| OD | Outer Diameter | +| OIT | Oxidative Induction Time, as applied to polyolefin materials | +| r or R | Radius of the element described | +| SZ | Reverse oscillating stranding | + +# 5 Conventions + +None. + +# 6 Characteristics of optical fibres and cables + +## 6.1 Optical fibre characteristics + +The following optical fibre types should be considered for use in the cables of this Recommendation, based on the agreement between manufacturers and customers. Single-mode optical fibres should be used as described in [ITU-T G.652], [ITU-T G.653], [ITU-T G.654], [ITU-T G.655], [ITU-T G.656] + +or [ITU-T G.657]. The corresponding IEC fibre category designations are shown in Appendix V of [b-ITU-T G Suppl.40]. + +#### **6.1.1 Transmission characteristics** + +The typical transmission characteristics are described for each optical fibre in its respective Recommendation. Unless specified otherwise by the users of the Recommendations, those values apply to the corresponding cabled optical fibre. + +The maximum point discontinuity at the operating wavelength(s) for fibres should be in accordance with [IEC 60794-1-1]. + +#### **6.1.2 Fibre microbending loss** + +Severe bending of an optical fibre involving local axial displacement of a few micrometres over short distances caused by localized lateral forces along its length can result in additional attenuation in the optical fibre and is called microbending loss. This may be caused by manufacturing and installation strains, and also during operation by dimensional variations of cable materials due to temperature changes. + +Microbending can cause an increase in the optical loss. In order to reduce microbending loss, stress randomly applied to a fibre along its axis should be minimized during the incorporation of the fibres into the cable, as well as during and after the cable installation. + +#### **6.1.3 Fibre macrobending loss** + +Macrobending is the resulting curvature, typically several mm in the radius of the element described (R), of an optical fibre. + +Macrobending of an optical fibre after cable manufacture and installation can cause an increase in the optical loss. The optical loss caused by macrobending typically increases as the bending radius is reduced. + +NOTE – [ITU-T G.657] optical fibres are optimized for reduced macrobending loss. + +#### **6.1.4 Fibre dimensions** + +Mode field diameter and cladding diameter are defined by the ITU-T G.65x-series Recommendations. + +The overall fibre dimensions and related characteristics such as non-circularity and concentricity are important in the performance of cabled fibre and in the splicing and connectorization of fibres. Accordingly, [IEC 60793-2-50] specifies critical values and measurement methods. The range of fibre outer coating diameter should be in accordance with [IEC 60793-2-50]. + +## **6.2 Mechanical characteristics** + +#### **6.2.1 Evaluation of mechanical characteristics** + +Cable mechanical characteristics should be evaluated using the test methods and requirements of [IEC 60794-3-11], and applicable recommendations in clause A.3. + +#### **6.2.2 Tensile strength** + +Optical fibre cable is subjected to short-term loading during manufacture and installation, and may be affected by continuous static loading and/or cyclic loading (e.g., temperature variation) during operation. Changes in the tension of the cable due to the variety of factors encountered during the service life of the cable can cause differential movement of the cable components. This effect should be considered in the cable design. Excessive cable tensile loading may increase the optical loss and may cause increased residual strain in the fibre if the cable cannot relax. When a cable is subjected to permanent loading during its operational life, the fibre should not experience strain beyond values that adversely affect fibre reliability (see clause A.3.1). To avoid these issues, the maximum tensile + +strength determined by the cable construction, especially the design of the strength member, should not be exceeded. + +##### **6.2.2.1 Tensile ratings** + +The standard tensile rating, tensile rating of a cable $L_S$ (or $L_M$ ), of cables per this Recommendation should be: + +$1.5 W$ , where $W$ is the force (N) exerted from the weight of 1 km of the cable that is suspended vertically. + +If the result exceeds 2 700 N, the tensile rating should be 2 700 N. + +The long-term or residual, load rating of a cable ( $L_L$ ) tensile rating, $L_L$ should be 30 per cent of the tensile rating $L_S$ . + +#### **6.2.3 Bending** + +Under the dynamic conditions encountered during installation, the fibre is subjected to strain from both cable tension and bending. The strength elements in the cable and the installation bend diameter should be selected to limit this combined dynamic strain. Routing and storage may result in permanent bends after installation. Any fibre bend radius remaining after the cable installation should be large enough to limit the macrobending loss or long-term strain limiting the lifetime of the fibre. + +Minimum bending diameter is an important parameter for the physical integrity of the sheath, for fibre strain limitation, and for fibre attenuation performance due to macrobending loss. Cables with smaller core structures can be bent to relatively smaller bend diameters than cables having larger core structures. + +##### **6.2.3.1 Minimum bending diameter** + +The standard minimum bending diameters for cables should be declared by the manufacturer. Cable bending diameters are defined as: + +Residual (installed): $20 \times$ cable OD or $30 \times$ cable OD, + +Loaded condition (during installation): $40 \times$ cable OD. + +For very small cables such as microduct cables, manufacturers may specify a fixed cable minimum bending diameter that is independent of the cable's outer diameter (OD). It should also be noted that the minimum bending diameter changes depending on the cable structure, such as the design and configuration of the strength members. + +NOTE – Some cable tests and specifications declare the bending criteria in terms of the radius of the apparatus or sheave. Care should be taken to avoid incorrect testing. + +#### **6.2.4 Crush** + +A duct or tunnel cable may be subjected to crush both during installation and the operational life. Characteristically, the crushing incident involves a relatively short length of the cable. The crushing may be short-term, as during installation, or may be long-term as over the operational life of the cable. + +The cable is constructed to isolate the optical fibres from external compressive forces. The construction and dimensions of the cable affect the resistance of the cable to performance degradation due to crushing. + +Crushing may damage the physical integrity of the cable or may increase the optical loss (either temporarily or permanently). Excessive stress may lead to fibre fracture. + +#### **6.2.5 Impact** + +A duct or tunnel cable may be subjected to impact both during installation and the operational life. Although in either case, the impact is a transient event, still it could result in the cable performance deformation and affect the cable over its operational life. + +Cable is constructed to isolate the optical fibres from external compressive forces. The construction and dimensions of the cable affect the resistance of the cable to performance degradation due to impact. + +Impact may damage the physical integrity of the cable or may increase the optical loss (either temporarily or permanently). Excessive stress may lead to fibre fracture. + +Characteristically impact could cause visible cracks, splits, tears, or other openings on the outer surface of the cable jacket. + +#### **6.2.6 Torsion** + +Under dynamic conditions encountered during installation and operation, a duct or tunnel cable may be subjected to torsion. This may be under tension during installation and the torsion may remain after the installation is complete. The torsion may be due to the coiling of the cable during installation and will often remain over the operational life of the cable. Torsion may result in optical loss of the fibres and/or damage to the sheath including the splitting of the sheath. The cable should be sufficiently robust to resist twisting, and its design should accommodate a reasonable number of cable twists per unit length without an increase in optical loss and/or damage to the sheath. + +Characteristically torsion could cause visible cracks, splits, tears, or other openings on the outer surface of the cable jacket. + +#### **6.2.7 Vibration** + +Vibration effects on duct and tunnel cables may occur when the cables are installed on structures or in areas where vibrations can be transmitted to the duct or the installed cable. + +When optical fibre cable ducts are installed on bridges, they will be subject to relatively high amplitude vibrations of various low frequencies, depending on the bridge construction and on the type of traffic density. Underground optical fibre cables in ducts or tunnels may be subject to persistent vibrations from traffic, railways, etc., or vibrations from infrequent activities such as pile-driving and blasting operations. + +In all cases, cables should withstand these vibrations without failure or performance degradation. + +Care should be exercised in the choice of the installation method. A well-established surveillance routine can identify the vibration activity, allowing for a careful choice of route to minimize this problem. + +## **6.3 Environmental characteristics** + +#### **6.3.1 Evaluation of environmental characteristics** + +Cable environmental characteristics should be evaluated using the test methods and requirements of [IEC 60794-3-11], and applicable discussion in clause A.4. + +#### **6.3.2 Temperature variations** + +During their operational lifetime, cables may be subjected to significant temperature variations. In these conditions, the increase of attenuation of the fibres should not exceed the specified limits. + +Duct and tunnel cables will typically experience a less severe range of temperature variations than other outdoor cables. However, parts of these cables may be deployed above ground or may experience freezing within their duct or tunnel. Also, these cables may be deployed in a high + +temperature environment such as in the vicinity of heating pipes. Therefore, a duct and tunnel cable should be sufficiently robust to perform in a wide range of temperature extremes. Accordingly, it is necessary to investigate, in advance, the operating temperature range of the location where the cable is to be laid, and to choose a cable design suitable for that environment. + +Cable elements can potentially have different thermal expansion coefficients that can cause differing dimensional changes among the cable elements. This can cause attenuation increases in the optical fibres due to microbending or macrobending effects. Therefore, testing of cables at temperature extremes is recommended. + +Due to the differing behaviours of cable materials at various temperatures, it should also be considered to specify the installation temperature range. Table 1 lists the normal temperature ranges appropriate for duct and tunnel cables. + +**Table 1 – Cable normal temperature ranges** + +| Condition | Temperature range | +|-------------------|-----------------------------------------------------------------------------------| +| Operation (°C) | –30 to +60 [IEC 60794-3-11] | +| Installation (°C) | 0 to +50 (PVC sheath) [b-IEC TR 62691]
–15 to +50 (PE sheath) [b-IEC TR 62691] | + +NOTE – Many existing specifications set the lower range limits for operation at –40 °C. Cables tested to these criteria should be considered compliant with the normal ranges above. + +#### 6.3.3 Water penetration + +In the event of damage to the cable sheath or to a splice closure, longitudinal penetration of water in a cable core or between components of the sheath can occur. Several types of problems with the fibre and cable components can occur. + +The presence of water in a cable core diminishes the tensile strength of the fibre, and the average time to static failure is reduced. The degree to which this can occur depends on the performance of the fibre coating, the length of fibre exposed, and the time of exposure. Water migrating to closures on cable ends can have a similar effect on fibres and splices. + +Water present in the cable sheath interstices is generally benign since most of the components are non-reactive to moisture. However, corrosion of metallic components can occur, and galvanic corrosion and the production of hydrogen can be accelerated. Reduction in the strength of non-metallic strength members can occur if the materials are susceptible to reactions with moisture. + +Water in the cable may freeze and, under some conditions, can cause fibre crushing which can produce macrobending and microbending that can result in increased optical loss and possible fibre breakage. + +The longitudinal penetration of water should be minimized or, if possible, prevented. In order to prevent longitudinal water penetration within the cable, techniques such as filling the cable core and sheath interstices completely with a compound or with discrete water blocks or swellable components (e.g., tapes, yarns, powders) should be used. In the case of unfilled cables, dry-gas pressurization can be used. Therefore, testing of cables for water penetration is recommended. + +A water penetration test measures the degree to which water may penetrate a specimen of cable that is subjected to a specified water head for a specified period. + +#### 6.3.4 Moisture permeation + +Moisture permeates the plastic materials commonly used in cable sheaths at some rate. As with water penetration, when moisture permeates the cable sheath and reaches the cable core, the tensile strength and lifetime of the fibre can be reduced. + +A prime deterrent against moisture damage is the performance of the fibre coatings. Various materials can be used as barriers to reduce the rate of moisture permeation through the sheath. A continuous metallic barrier is effective in minimizing or preventing moisture permeation; a minimum permeation is achieved by a sealed longitudinal overlapped metallic foil or tape (glued, thermo welded, or welded). In metal-free cables, filling compounds which are effective in preventing longitudinal water propagation, do not significantly hinder radial moisture permeation through plastic sheaths. + +#### 6.3.5 Pneumatic resistance + +Pneumatic resistance of unfilled (air core) cables is an important parameter in systems which use dry-gas pressurization to protect cable cores from moisture. Such systems require some flow of the dry gas to scavenge moisture which enters the pressurized portion of the cable – usually the core or inner jacket structure. To that end, the core must allow passage of the gas under the system design criteria. + +Conversely, cables may pass through a barrier for which gas leakage is to be minimized – environmental containment and watertight bulkheads are examples. Such cables are designed with high pneumatic resistance. + +NOTE – It is intended that a cable can be pressurized only if it allows a flux of air which is in accordance with the criteria defined in Chapter 2 of [b-ITU-T TR.ofcs]. + +#### 6.3.6 Freezing + +Freezing of duct cables may occur when the temperature of the ground in which the duct resides drops below the freezing temperature. Ducts are characteristically buried below the frost line, but local variations or transitions out of the ground may result in freezing. Tunnel cables may also experience freezing temperatures, though this is less frequent. The maximum expansion of frozen water occurs at $-2^{\circ}\text{C}$ , so extreme conditions are not required for cable freezing. + +The ground surrounding ducts having cables within will frequently be wet, so freezing may occur. Ducts may transition through maintenance holes or other structures where water may pool. And ducts may experience water within the duct between the cables and the duct walls. The effects of such freezing primarily depend on the rigidity of the duct and the robustness of the cable. Many ducts are flexible and do not significantly resist the expansion of frozen water, either internally or externally. Some ducts are metallic pipes or concrete ducts and resist the forces of external freezing, but contain the forces of water freezing within. + +Water within a cable from moisture permeation or water penetration may be frozen and under some conditions can cause fibre crushing with a resultant increase in optical loss and possible fibre breakage. Cable characteristics that address water penetration and moisture permeation can minimize such risks. + +##### 6.3.6.1 External freezing + +In general, external freezing is only a hazard when the cable is confined within a rigid duct structure such as a metallic pipe or concrete duct and the duct has water within it. This is addressed in clause 6.3.6.2. + +For more common flexible ducts, freezing of the ground surrounding the duct or within the duct has been found to be of little risk. Similarly, freezing of water pooled about exposed cables has been found to be of little risk. The robustness of duct and tunnel cables necessary to meet the combined performance criteria is generally sufficient for cables to resist crushing due to external freezing. Testing for such conditions is addressed by clause A.4.6. + +##### 6.3.6.2 Freezing in a confined space + +Freezing of water surrounding an optical cable within a rigid duct can cause significant crushing forces due to the restrained expansion of the water as it freezes. In applications where this hazard is + +expected, installation methods using extremely robust cable designs or pressure absorber elements may be used. Testing for such conditions is addressed by clause A.4.6. + +#### 6.3.7 Ageing + +Optical cables are designed to have stable performance over many years – typically 20 years or more. Changes in the performance of fibres and cables over their lifetime are very important. End of Life (EoL) as applied to cable testing and criteria performance of fibres and cables has been very good, due to accepted and conservative design principles. + +Testing for ageing evaluates the reaction of cable components under simulated ageing by applying high temperatures over extended periods of time. This is not end of life testing, but beginning of life (BoL) as applied to cable testing and criteria characterization. The results of such testing may be used to reach an agreement between manufacturers and customers. Nonetheless, aspects for the performance of cables in simulated ageing are agreed; these are addressed in clause A.4.2. + +#### 6.3.8 Hydrogen gas + +In the presence of moisture and metallic elements, hydrogen gas may be generated. Hydrogen gas may diffuse into silica glass and increase optical loss. It is recommended that the hydrogen gas concentration in the cable, as a result of its component parts should be low enough to ensure that the long-term effects on the increase of optical loss are acceptable. The method for estimating the concentration of hydrogen gas in optical cables is given in [ITU-T L.126]. Further information can be found in [b-IEC TR 62690]. + +Fibre design has minimized these effects in the wavelengths used for optical transmission. And, by using dynamic gas pressurization and hydrogen absorbing materials, and by careful material selection and construction, the increase in optical loss can be maintained within the acceptable limits over the operational life of the cable. + +## 6.4 Fire safety + +Fire safety in duct and tunnel cables is generally an issue in the installation criteria and possible fire safety restrictions; refer to the regional and national norms. + +In most countries, optical cables for tunnel or building entrance installations are required to meet fire performance requirements. Requirements for fire performance may differ in each country. Optical cables for tunnels or building entrances should meet fire safety regulations in each country or in accordance with those of each telecommunication carrier. The following IEC standards should be considered if no fire safety specifications are provided and should be selected according to the application: [IEC 60331-25], [IEC 60332-1-2], [IEC 60332-3-24], [IEC 60754-1], [IEC 60754-2], [IEC 61034-1] and [IEC 61034-2]. Guidance is found in [b-IEC TR 62222]. + +## 6.5 Biotic damage + +The size and deployment of an optical fibre cable can make it vulnerable to biological attacks. + +Cables within ducts are less vulnerable to rodent attack than aerial or buried cables. But cable ends in maintenance holes may be vulnerable. Cables installed on tunnel walls may be vulnerable throughout their length. Both types are subject to insect exposure, though damage from insects is not common. + +Duct and tunnel cables are commonly jacketed with polyethylene, which is non-nutritive to fungus. Fire retardant jacket materials should be selected to similarly be non-nutritive. + +This topic is covered in [ITU-T L.161]. + +## **6.6 Electrical characteristics** + +#### **6.6.1 Lightning** + +Fibre cables containing metallic elements such as metallic sheaths, strength members, hybrid cable conventional copper pairs, or coaxial units are susceptible to lightning strikes. While less susceptible than directly-buried cables, lightning fields in the ground surrounding ducts, or metallic components in tunnel structures or adjacent cables can arc to duct and tunnel cables causing damage. + +To prevent or minimize lightning damage, consideration should be given to [ITU-T K.29] and [ITU-T K.47]. + +### **6.6.2 Electrical continuity** + +If metallic elements are used in the cable, they should be electrically continuous. The resistivity of the metallic members should be checked if specified. The reference test method is [IEC 60794-1-403]. + +# **7 Cable construction** + +## **7.1 Fibre coatings** + +#### **7.1.1 Primary coating** + +Silica fibre itself has an intrinsically high strength, but its strength is reduced by surface flaws. A protective primary coating is characteristically applied immediately after drawing the fibre to size. + +The optical fibre should be proof-tested. In order to guarantee long-term reliability under service conditions, the proof-test strain may be specified, taking into account the permissible strain and required lifetime. Agreed norms for fibre strain in testing and service are discussed in clause A.3.1. + +NOTE 1 – The optical fibres should be proof tested with a strain equivalent to 1 per cent or as agreed. For certain applications, a larger proof-test strain may be necessary. + +In order to prepare the fibre for splicing, it should be possible to remove the primary coating without damage to the fibre, and without the use of materials or methods considered to be hazardous or dangerous. + +The composition of the primary coating, coloured if required should be considered in relation to any requirements of local light-injection and detection equipment used in conjunction with the fibre jointing methods. + +NOTE 2 – Further study is required to advise on suitable testing methods for local light-injection and detection. + +Primary-coated fibres should comply with the relevant optical fibre specifications in [IEC 60793-2-50]. + +#### **7.1.2 Fibre buffer (secondary coating)** + +A secondary coating, termed a buffer, may be applied directly over the fibre primary coating for a variety of reasons. This is not to be confused with a buffer tube, which is discussed in clause 7.2.4. + +Buffers may use single or multiple materials. The buffer may be a tight buffer, intimately in contact with the primary coating, or a semi-tight buffer, in contact with the primary coating but intended for removal without damaging the primary coating. + +Both types of fibre buffer, if used, should comply with the requirements given in [IEC 60794-3]. + +NOTE – When a fibre buffer is used, it may be difficult to use a local light-injection and detection equipment associated with fibre jointing methods. + +#### **7.1.3 Fibre identification** + +Fibre should be easily identified by colour/tracer/marker and/or position within the cable core. If a colouring method is used, the colours should be clearly distinguishable and have good colour + +permanence properties, also in the presence of other materials during the lifetime of the cable. The need for fibre identification extends to the fibre units (ribbons, slots, buffer tubes, bundles, micro-bundles, etc.). Unit identification may include colours, printed marks, position in the core, or other appropriate means. + +Guidance may be found in [b-IEC TR 63194]. + +#### 7.1.4 Removability of coating + +The primary and secondary coatings should be easy to remove and should not hinder the splicing, or fitting of fibre to the optical connectors. + +## 7.2 Cable elements + +The make-up of the cable core – in particular the number of fibres, their method of protection and identification, and the location of strength members and metallic wires or pairs, if required – should be clearly defined. + +#### 7.2.1 Fibre bundle + +Grouping optical fibres into bundled units is a common method of organizing and identifying fibres within cable cores. Such bundles are commonly assembled using spirally-applied threads or tapes, often colour-coded, to assist in fibre identification. Other methods following this intent may be used. Such bundles may reside in a slotted core (see clause 7.2.3), buffer tubes (see clause 7.2.4), micro-modules (see clause 7.2.5), or other core structures. + +#### 7.2.2 Fibre ribbon + +Optical fibre ribbons should conform to [IEC 60794-1-31]. + +Optical fibre ribbons consist of optical fibres aligned in a row. Optical fibre ribbons are designated by types, based on the method used to bind the fibres. Common types are the edge-bonded type, the encapsulated type, and the partially-bonded type. These are shown in Figures 1, 2, and 3, respectively. + +In the case of the edge-bonded type, optical fibres are bound by adhesive material located between the optical fibres. In the encapsulated type, optical fibres are bound by coating material covering the entire ribbon structure. In either of these basic types, the partially-bonded configuration may be used to accomplish additional flexibility in the transverse direction. This allows the ribbon to be rolled and accommodated in small core structures. + +The fibres of optical fibre ribbons in the as-manufactured configuration should be parallel and not cross. Optical fibre ribbons should be capable of mass splicing. Each ribbon in a cable should be identified by a printed legend or a unique colour (see also clause 7.1.3). + +![Cross-section of a typical edge-bonded ribbon](a538e783a7a6643b5a333e04fe07615d_img.jpg) + +The diagram shows two identical cross-sectional views of an edge-bonded optical fibre ribbon. Each view consists of four white circles (representing optical fibres) arranged in a horizontal row. The circles are separated by thin black vertical lines, representing the adhesive material used to bind them. The word "or" is placed between the two identical diagrams. Below the right-hand diagram is the label "L.100(21)\_F01". + +Cross-section of a typical edge-bonded ribbon + +Figure 1 – Cross-section of a typical edge-bonded ribbon + +![Cross-section of a typical encapsulated ribbon](c6478031026050daaf731365b58b6e88_img.jpg) + +The diagram shows a cross-sectional view of an encapsulated optical fibre ribbon. It consists of four white circles (representing optical fibres) arranged in a horizontal row, all enclosed within a single, solid black rectangular border, which represents the encapsulating coating material. Below the diagram is the label "L.100(21)\_F02". + +Cross-section of a typical encapsulated ribbon + +Figure 2 – Cross-section of a typical encapsulated ribbon + +![Figure 3: A perspective view of a ribbon cable showing its internal structure. The ribbon is composed of multiple layers. Arrows labeled 'Not bonded' point to the top layers, while arrows labeled 'Bonded' point to the bottom layers, indicating a partial bonding configuration.](3267a096e9ca525744d8cd820f12eb59_img.jpg) + +L.100(21)\_F03 + +Figure 3: A perspective view of a ribbon cable showing its internal structure. The ribbon is composed of multiple layers. Arrows labeled 'Not bonded' point to the top layers, while arrows labeled 'Bonded' point to the bottom layers, indicating a partial bonding configuration. + +**Figure 3 – Example of a typical partially-bonded ribbon** + +#### 7.2.3 Slotted core + +In order to avoid direct pressure from the outside of the cable on optical fibres, optical fibres and/or fibre ribbons or other units may be located in slots inside a core structure. Usually, slots are provided in a helical or reverse oscillating stranding (SZ) method configuration on a cylindrical rod. The slotted core rod usually contains a strength member (metallic or non-metallic). The strength member should adhere tightly to the slotted core in order to obtain temperature stability and avoid separation when a pulling force is applied during installation. Water-blocking material may be contained within the slots. + +![Figure 4: A cross-sectional view of a slotted core structure cable. It shows a central 'Strength member (Tension member)' surrounded by a 'Slotted core' with 11 slots. Each slot contains a 'Ribbon'. The entire assembly is covered by an outer 'Sheath'. The slots are numbered 1 through 11.](8935d7297fc189503125ecbbd7c41f27_img.jpg) + +L.100(21)\_F04 + +Figure 4: A cross-sectional view of a slotted core structure cable. It shows a central 'Strength member (Tension member)' surrounded by a 'Slotted core' with 11 slots. Each slot contains a 'Ribbon'. The entire assembly is covered by an outer 'Sheath'. The slots are numbered 1 through 11. + +**Figure 4 – Example of a slotted core structure cable** + +#### 7.2.4 Tube (buffer tube) + +A tube construction, commonly called a buffer tube or loose tube, is frequently used for protecting and gathering optical fibres, fibre bundles, and/or fibre ribbons. The essential feature of the tube is sufficient space inside the tube to isolate fibres, fibre bundles, or ribbons from external stress. The tubes are commonly made of polymer materials. Cable designs incorporating loose tubes are the most widely deployed, offering an optimized package for handling and robustness. The tubes may be stranded around the other tubes or the central strength member. Such core structures minimize strain and mid-span access may be easier if the SZ method is utilized. Central tube designs may also be used. Water-blocking material may be contained in the tube, if required. + +![Diagram of a loose tube cable construction showing a central strength member, buffer tubes containing fibres, water blocking material, ripcord, and an outer sheath (jacket).](cd91fd97c6e4da454b42f4fde13f7e44_img.jpg) + +This diagram illustrates a cross-section of a loose tube cable. At the center is a 'Central strength member'. Surrounding this are several 'Buffer tube' units, each containing multiple 'Fibre' units. The buffer tubes are embedded in 'Water blocking material'. A 'Ripcord' is shown as a thin line within the 'Outer sheath (Jacket)'. A label 'Water blocking/binding tape/strength member' points to the inner layer of the jacket. The diagram is labeled L.100(21)\_F05. + +Diagram of a loose tube cable construction showing a central strength member, buffer tubes containing fibres, water blocking material, ripcord, and an outer sheath (jacket). + +**Figure 5 – Example of a loose tube cable construction** + +#### 7.2.5 Micro-module + +A micro-module is a thin-walled tubing unit (typically smaller and less robust than the buffer tube described in clause 7.2.4). These flexible modules have bending radii similar to the unbundled fibre or fibre bundles and are easy to strip without a tool for easy splice preparation and mid-span access. They have no shape memory and may be used directly in an enclosure up to the splicing tray. Water-blocking material may be contained within the micro-module, if required. Micro-modules may be used within buffer tubes or slots. A typical micro-module is shown in Figure 6. + +![Diagram of a micro-module showing thin and low modules wall tubing, fibres, and filling compound or dry filling solution.](715cc21be1e312bb659bf6de41740408_img.jpg) + +This diagram shows a cross-section of a micro-module. It consists of 'Thin and low modules wall tubing' which contains a bundle of 'Fibre' units. The space between the fibres is filled with 'Filling compound or dry filling solution'. The diagram is labeled L.100(21)\_F06. + +Diagram of a micro-module showing thin and low modules wall tubing, fibres, and filling compound or dry filling solution. + +**Figure 6 – Example of primary coated fibres protected by micro-module** + +#### 7.2.6 Ruggedized fibre + +When required for particular applications, further protection for a buffered fibre (see clause 7.1.2) may be provided by surrounding one or more such fibres with an assembly of strength elements, typically non-metallic, and an appropriate jacket material. Such assemblies are small in size and typically reside in the cable core. Such ruggedization may be appropriate for break-out / fan-out cable constructions. + +![Diagrams of ruggedized fibre structure showing a single fibre and a dual fibre assembly, both with buffered fibre, aramid yarn, and sheath.](d634064028e40596aebaa55b4f9700cc_img.jpg) + +This diagram shows two examples of ruggedized fibre structure. The left example shows a single 'Buffered fibre' surrounded by 'Aramid yarn' and an outer 'Sheath'. The right example shows two 'Buffered fibre' units side-by-side, each surrounded by 'Aramid yarn' and an outer 'Sheath'. The diagram is labeled L.100(21)\_F07. + +Diagrams of ruggedized fibre structure showing a single fibre and a dual fibre assembly, both with buffered fibre, aramid yarn, and sheath. + +**Figure 7 – Examples of ruggedized fibre structure** + +#### **7.2.7 Strength member** + +The duct and tunnel cable should be designed with sufficient strength members to meet installation and service conditions so that the fibres themselves are not subjected to strain levels in excess of the standard values (see clause A.3.1) or as agreed upon between the customer and manufacturer. + +Strength members mainly serve to limit tensile strain, but may also serve to limit compressive strain as in temperature changes. The strength members may be located within the core or in the sheath layers, or both. The strength member(s) may be either metallic or non-metallic. + +When metallic strength members are used, they should be electrically continuous (see clause 6.6.2) and care should be taken to avoid hydrogen generation effects (see clause 6.3.8) and lightning hazards (see clause 6.6.1). + +#### **7.2.8 Water-blocking materials** + +Most duct and tunnel cables are water-blocked to protect the fibres from water ingress (see clause 6.3.3 regarding air-core cables). Filling a cable – core and sheath interstices – with water-blocking material or wrapping these areas with layers of water-swellable material, or both, are common methods to protect the fibres from water ingress. A water-blocking element – filling compound, water-swellable yarns or tapes, water-swelling powder, or combinations of materials – may be used. Any materials used should not be harmful to personnel. The materials in the cable should be compatible with one another, and in particular, should not adversely affect the fibre. These materials should not hinder splicing and/or connection operations (see clause A.4.7). + +## **7.3 Sheath and jacket** + +The cable sheath is the assembly of elements that cover the cable core. This term may also be used to mean the part of the assembly, which is the main covering of the cable often termed the jacket. The cable core should be covered with a sheath or sheaths suitable for the relevant environmental and mechanical conditions associated with storage, installation and operation. The sheath may be of a composite construction and may include strength members. The sheath may include a moisture barrier or inner jacket or armour as needed, in addition to an outer jacket. The materials of the sheath should be compatible with all of the elements of the cable sheath and core. + +#### **7.3.1 Moisture barrier** + +A moisture barrier may be one element of a cable sheath to inhibit moisture permeation (see clause 6.3.4). If used, consideration should be given to the amount of hydrogen generated from a metallic moisture barrier (see clause 6.3.8). + +#### **7.3.2 Inner sheath (jacket)** + +An inner sheath (jacket) layer may be used in the cable construction. The inner sheath may provide additional protection under an armour and may be used to organize a cable as in break-out / fan-out cables, or for other reasons. + +#### **7.3.3 Outer sheath (jacket)** + +The outer sheath (jacket) is the final covering of the cable. The selection of the outer sheath material should be selected to resist the expected environmental hazards. The outer sheath material of duct cables should optimize the friction forces between the cable sheath and duct. For tunnel cables, the sheath construction – particularly the outer sheath material – should consider the restrictions associated with fire hazards. + +NOTE – One of the most commonly used sheath materials is polyethylene. There may however be some conditions where it is necessary to use other materials, for example, to limit fire hazards; to protect from rodents and/or termites, etc. + +## 7.4 Armour + +Where protection from external damage (e.g., crush, impact, rodents) or additional tensile strength is required armour should be provided. + +Common metallic armour materials are steel tapes of various constructions. The armour should also provide sufficient radial as well as compressive strength and the metallic armour should be electrically continuous (see clause 6.6.2) and bonded to the outer sheath if armouring acts as a moisture barrier. Other metallic materials are occasionally used. Heavy armour such as stranded wire servings is generally not used for duct or tunnel cables. Hydrogen generation due to corrosion must be taken into consideration (see clause 6.3.8). + +Armour for metal-free cables may consist of aramid yarns, glass-fibre-reinforced strands, strapping tape, etc. + +It should be noted that the advantages of optical fibre cables, such as lightness and flexibility will be reduced when armour is provided. + +## 7.5 Identification of cable + +It is recommended that a visual identification of optical fibre cables be provided: this can be done by visibly marking the outer sheath. The marking of the cable length should be included in the cable marking. For identifying and length-marking cables, embossing, sintering, imprinting, hot foil, or ink-jet or laser printing can be used by agreement between the manufacturer and customer. + +## 7.6 Cable sealing + +It is recommended that an optical fibre cable should be provided with cable end-sealing and protection during cable delivery and storage. If splicing components have been factory installed, they should be adequately protected. Pulling devices can be fitted to the end of the cable, if required. + +## 7.7 Considerations for duct installation + +Installation of optical cables within ducts involves additional issues which should be considered. The geometry of the duct run – access, bends, elevation changes, duct size – may inform the installation method to be used. "Proving" of the duct – assessment that the duct is clear of debris and not crushed – should be performed before any installation. + +### 7.7.1 Installation method + +In cable pulling, the pulling force should not exceed the cable tensile rating. The use of installation lubrication can be of benefit. + +NOTE – In addition to cable pulling, some cables in ducts are installed by the blowing method but pulling and blowing have different cable requirements and conditions. See [ITU-T L.108] for cable requirements and installation conditions applicable to the blowing installation. + +The duct filling ratio—the comparison of the duct inner diameter to the cable outer diameter – should be considered for determining the cable size (outer diameter). The presence of other cables already in the duct should be considered. + +### 7.7.2 Cable design considerations + +The primary design consideration for pulling installation is the tensile rating of the optical cable. + +The friction between the cable outer jacket and the duct inner surface should be carefully considered. This is the main effect of installation tension. The duct filling ratio affects this consideration – both in the materials and the cable size. The presence of other cables in the duct and their jacket characteristics should be considered. The use of installation lubricants should be considered for the installation method. + +# Annex A + +## Test methods + +(This annex forms an integral part of this Recommendation.) + +The tests are according to [IEC 60794-3-11] and the clauses below should be carried out for duct and fibre cables. The attribute values stated herein should be used to assess conformance in the tests. It is not intended that all tests should be carried out; see [IEC 60794-3-11] for guidance. See [IEC 60794-3] regarding the frequency of testing; this should be agreed upon between the manufacturer and the customer. + +The test methods, performance and test criteria are summarized in the following Tables A.1 to A.7. + +**Table A.1 – Optical fibre and cable elements test conditions** + +| Characteristic | Clause | Test 1 | Value 1, 2, 3 | Note | +|----------------------------|--------|-------------------|---------------------------------------------------------|------------------------| +| Attenuation coefficient | A.1.3 | [IEC 60793-1-40] | see Note 4 | | +| No changes in attenuation | A.1.3 | – | as specified in Note 5 | as per [IEC 60794-1-1] | +| No changes in fibre strain | A.1.3 | as applicable | as specified in Note 5 | as per [IEC 60794-1-1] | +| Ambient temperatures | A.1.4 | as applicable | standard ambient and expanded ambient, see clause A.1.4 | as per [IEC 60794-1-2] | +| Other temperatures | A.1.5 | as applicable | within $\pm 5$ °C of the specified value | | + +NOTE 1 – Tests are IEC unless otherwise specified. Letter/number tests are per the [IEC 60794-1-2] series unless otherwise specified. +NOTE 2 – "As agreed" means per agreement between the manufacturer and the customer. +NOTE 3 – Reference to the L.100 invoking clause implies criteria not detailed in [IEC 60794-3-11] or the test method and which is overly complex for this table. +NOTE 4 – Cabled fibre attenuation coefficient is specified in the corresponding ITU-T G.65x series Recommendation. +NOTE 5 – No changes in attenuation/strain are related to the test uncertainty as per [IEC 60794-1-1]. + +**Table A.2 – Optical fibre and cable elements characteristics** + +| Characteristic | Clause | Test 1 | Value 1, 2, 3 | Note | +|-----------------------------|---------|-------------------------------------------|--------------------------|----------------------| +| Fibre dimensions | A.2.1.1 | [IEC 60793-1-21] | per [IEC 60793-2-50] | per [IEC 60793-2-50] | +| Fibre coating strippability | A.2.1.2 | [IEC 60793-1-32] | per [IEC 60794-3-11] | | +| Material compatibility | A.2.1.3 | [IEC 60794-1-219] | [IEC 60794-1-219] | | +| Fibre buffers dimensions | A.2.3.1 | [IEC 60793-1-21]
or
[IEC 60811-203] | per [IEC 60794-3] or DS | | +| Buffer strippability | A.2.3.2 | E5C of
[IEC 60794-1-21] | see clause A.2.3.2 | | +| Buffer tube dimensions | A.2.4.1 | [IEC 60811-202]
and
[IEC 60811-203] | per DS or as agreed | | + +**Table A.2 – Optical fibre and cable elements characteristics** + +| Characteristic | Clause | Test 1 | Value 1, 2, 3 | Note | +|----------------------|---------|---------------------------------------------|-----------------------------|------| +| Tube kink | A.2.4.2 | G7 of [IEC 60794-1-23] | per [IEC 60794-3-11] | | +| Fibre ribbons | | [IEC 60794-1-31]
and
[IEC 60794-3-11] | | | +| Ribbon dimensions | A.2.5.1 | [IEC 60794-1-31] | Table 1 of [IEC 60794-1-31] | | +| Fibre separability | A.2.5.2 | [IEC 60794-1-31] | [IEC 60794-1-31] | | +| Ribbon strippability | A.2.5.3 | [IEC 60794-1-31]
and
[IEC 60793-1-32] | [IEC 60794-1-310] | | + +NOTE 1 – Tests are IEC unless otherwise specified. Letter/number tests are per the [IEC 60794-1-2] series unless otherwise specified. +NOTE 2 – "As agreed" means per agreement between the manufacturer and the customer. +NOTE 3 – Reference to the L.100 invoking clause implies criteria not detailed in [IEC 60794-3-11] or the test method and which is overly complex for this table. + +**Table A.3 – Mechanical characteristics** + +| Characteristic | Clause | Test 1 | Value 1, 2, 3 | Note | +|-------------------------|--------|---------------------------------------|---------------------------------------------------------------------------------|----------------------------------| +| Tensile strength | A.3.1 | E1 of [IEC 60794-1-21] | L M per 6.2.2 | per [IEC 60794-3-11] | +| Bending | A.3.2 | E11 of [IEC 60794-1-21] | per [IEC 60794-3-11] | E11A or E11B of [IEC 60794-1-21] | +| Bending under tension | A.3.3 | E18A, Procedure 2 of [IEC 60794-1-21] | per [IEC 60794-3-11] | | +| Repeated bending (flex) | A.3.4 | E6 of [IEC 60794-1-21] | per [IEC 60794-3-11]
No change in attenuation after the test | | +| Crush | A.3.5 | E3A of [IEC 60794-1-21] | per [IEC 60794-3-11]
see clause A.3.5 | plate/plate crush | +| Impact | A.3.6 | E4 of [IEC 60794-1-21] | per [IEC 60794-3-11]
see clause A.3.6 | | +| Torsion | A.3.7 | E7 of [IEC 60794-1-21] | per [IEC 60794-3-11]
see clause A.3.7 | | +| Abrasion, cable print | A.3.8 | E2A, Method 2 of [IEC 60794-1-21] | per [IEC 60794-3-11] | jacket abrasion not tested | +| Cable kink | A.3.9 | E10 of [IEC 60794-1-21] | 1 sample, ambient temperature, no kink, $d > \text{minimum}$ per clause 6.2.3.1 | not in [IEC 60794-3-11] | +| Vibration | A.3.10 | – | see clause A.3.10 | not usually required | + +NOTE 1 – Tests are IEC unless otherwise specified. Letter/number tests are per the [IEC 60794-1-2] series unless otherwise specified. +NOTE 2 – "As agreed" means per agreement between the manufacturer and the customer. +NOTE 3 – Reference to the L.100 invoking clause implies criteria not detailed in [IEC 60794-3-11] or the test method and which is overly complex for this table. + +**Table A.4 – Environmental characteristics** + +| Characteristic | Clause | Test 1 | Value 1, 2, 3 | Note | +|-----------------------------------------------------------------------------------------------|-----------------------------|---------------------------------------------------|------------------------------------------------|--------------------------------------------------| +| Temperature cycling | A.4.1 | F1 of [IEC 60794-1-2] | see clause 6.3.2 | | +| Ageing | A.4.2 | F9 of [IEC 60794-1-2] | as agreed | may be an extension of F1 of [IEC 60794-1-2] | +| Water penetration | A.4.3 | F5B or F5C of [IEC 60794-1-2], as applicable | per [IEC 60794-3-11]
no leakage after 24 hr | | +| Moisture penetration | A.4.4 | Chapter 2 of [b-ITU-T TR.ofcs] | as agreed | not commonly tested | +| Pneumatic resistance | A.4.5 | F8 of [IEC 60794-1-2] | as agreed | | +| Freezing | A.4.6 | Method A or B of [IEC 60794-1-215], as applicable | as agreed | applicability dependent on deployment conditions | +| Material compatibility
– Jacket tensile, aged
– Metal coatings
delamination testing. | A.4.7
A.4.7.2
A.4.7.3 | [IEC 60794-1-219] | ≥ 75% of unaged
no delamination | | +| Oxidative induction time, as applied to polyolefin materials (OIT) | A.4.8 | [ISO 11357-6] and per A.4.8 | OIT ≥ 20 minutes. | | +| Hydrogen | A.4.9 | – | see [ITU-T L.126] and [b-IEC TR 62690] | not usually required | +| Nuclear radiation | A.4.10 | F7 of [IEC 60794-1-2] | see clause A.4.10 | not usually required | +| Cable sheath adherence | A.4.11 | [IEC 61196-1-313] | see clause A.4.11 | for flooded-armour constructions | + +NOTE 1 – Tests are IEC unless otherwise specified. Letter/number tests are per the [IEC 60794-1-2] series unless otherwise specified. +NOTE 2 – "As agreed" means per agreement between the manufacturer and the customer. +NOTE 3 – Reference to the L.100 invoking clause implies criteria not detailed in [IEC 60794-3-11] or the test method and which is overly complex for this table. + +**Table A.5 – Biotic characteristics** + +| Characteristic | Clause | Test 1 | Value 1, 2, 3 | Note | +|--------------------------------------------------|--------------------|--------------------|------------------------------------------------------------|------| +| Biotic damage
– Rodent and insect
– Fungus | A.5.1.1
A.5.1.2 | –
[ITU-T L.161] | as agreed, clause see 6.5
as agreed, clause see A.5.1.2 | | + +NOTE 1 – Tests are IEC unless otherwise specified. Letter/number tests are per the [IEC 60794-1-2] series unless otherwise specified. +NOTE 2 – "As agreed" means per agreement between the manufacturer and the customer. +NOTE 3 – Reference to the L.100 invoking clause implies criteria not detailed in [IEC 60794-3-11] or the test method and which is overly complex for this table. + +**Table A.6 – Electrical characteristics** + +| Characteristic | Clause | Test 1 | Value 1, 2, 3 | Note | +|-----------------------|--------|-------------------|-----------------------------|----------------------------------| +| Lightning | A.6.1 | [ITU-T K.47] | see clause 6.6.1 | not usually required | +| Electrical continuity | A.6.2 | [IEC 60794-1-403] | as agreed, see clause A.6.2 | for cable with metallic elements | + +NOTE 1 – Tests are IEC unless otherwise specified. Letter/number tests are per the [IEC 60794-1-2] series unless otherwise specified. +NOTE 2 – "As agreed" means per agreement between the manufacturer and the customer. +NOTE 3 – Reference to the L.100 invoking clause implies criteria not detailed in [IEC 60794-3-11] or the test method and which is overly complex for this table. + +**Table A.7 – Cable construction** + +| Characteristic | Clause | Test 1 | Value 1, 2, 3 | Note | +|---------------------------|---------|-------------------------------------|--------------------------------------------------|------| +| Dimensions | A.2.6.1 | [IEC 60811-202] and [IEC 60811-203] | as agreed | | +| Cable OD | A.2.6.2 | [IEC 60811-203] | stated by the manufacturer, per [IEC 60794-3-11] | | +| Sheath thickness | A.2.6.3 | [IEC 60811-203] | per [IEC 60794-3-11] or as agreed | | +| Moisture barrier adhesion | A.2.6.4 | [IEC 60708] | per [IEC 60794-3-11] | | + +NOTE 1 – Tests are IEC unless otherwise specified. Letter/number tests are per the [IEC 60794-1-2] series unless otherwise specified. +NOTE 2 – "As agreed" means per agreement between the manufacturer and the customer. +NOTE 3 – Reference to the L.100 invoking clause implies criteria not detailed in [IEC 60794-3-11] or the test method and which is overly complex for this table. + +### A.1 Standard test criteria + +#### A.1.1 Tensile strength of duct and tunnel cables + +Testing for criteria involving cable tensile strength should be carried out using the tensile rating of clause 6.2.2. + +#### A.1.2 Temperature test values for duct and tunnel cables + +Testing for criteria involving defined temperature extremes should be considered to be carried out using the temperature ranges. Some tests may specify specific test temperatures different from the standard temperature ranges. + +#### A.1.3 Attenuation coefficient and changes (no change and allowable change) in attenuation/strain in cable testing + +Unless otherwise specified, testing for attenuation requirements should be carried out at 1 550 nm for all single-mode fibres. + +Unless otherwise specified, changes in attenuation should be calculated with respect to the attenuation values before the start of the test. In most cases, this measurement should be at ambient temperature (see clause A.1.4). + +Unless otherwise specified, for tests with attenuation requirements the attenuation increase or decrease at the completion of the test should be no change. + +Unless otherwise specified, the defined values for "no change" should be per [IEC 60794-1-1], which are: + +- single-mode, attenuation change $\leq 0.05$ dB at 1 550 nm +- single-mode, attenuation coefficient change $\leq 0.05$ dB/km at 1 550 nm +- all types, no change in fibre strain $\leq 0.05\%$ + +#### A.1.4 Ambient temperatures for cable testing + +The ambient temperatures for cable testing should be according to [IEC 60794-1-2] as shown in Table A.8. All testing should use the expanded ambient criteria unless disallowed by the test procedure or as agreed. + +**Table A.8 – Ambient temperature, relative humidity, and atmospheric pressure** + +| Condition | Standard ambient | Expanded ambient | +|----------------------|--------------------------------------------|---------------------------------------------| +| Temperature | $23^{\circ}\text{C} \pm 5^{\circ}\text{C}$ | $25^{\circ}\text{C} \pm 15^{\circ}\text{C}$ | +| Relative humidity | 20% to 70% | 5% to 95% | +| Atmospheric pressure | Site ambient | Site ambient | + +#### A.1.5 Temperature precision at extremes + +The temperature value at test temperatures other than ambient should be within $\pm 5^{\circ}\text{C}$ of the specified values (see clause 6.3.2 and clause A.1.4). + +### A.2 Test methods for cable elements + +#### A.2.1 Tests applicable to optical fibres + +In this clause, optical fibre test methods for assessing fibres and test methods related to splicing and other joining methods are described. Mechanical and optical characteristics test methods for optical fibres are described in [ITU-T G.650.1], [ITU-T G.650.2] and IEC 60793-1-xx fibre test methods series. + +##### A.2.1.1 Dimensions + +For measuring the primary coating diameter, method [IEC 60793-1-21] should be used. + +The measured dimensions for cabled fibre should be per [IEC 60793-2-50] or as agreed. + +##### A.2.1.2 Coating strippability + +For measuring the strippability of primary or secondary fibre coatings, method [IEC 60793-1-32] should be used. The strip force should be according to [IEC 60794-3-11]. + +##### A.2.1.3 Compatibility with filling materials + +When fibres come into contact with a filling material used for waterproofing, the stability of the fibre coating and the filling material should be examined by tests after the accelerated ageing. + +Compatibility of optical fibres and buffers with a filling material should be tested per [IEC 60794-3-11]. + +Dimensional stability and coating transmissivity should be examined by the test method as agreed. + +#### A.2.2 Tests applicable to fibre units + +##### A.2.2.1 Colour coding of fibre + +There is no international standard on fibre colour coding. The fibre colouring should comply with the detailed specification (DS), which may reflect in the national or regional norms. See [b-IEC TR 63194] for guidance. + +Colours used should comply with [IEC 60304]. + +##### A.2.2.2 Fibre and unit identification + +Fibre and unit identification should also comply with the DS, which may reflect in the national or regional norms. See [b-IEC TR 63194] for guidance. + +Colours used should comply with [IEC 60304]. + +#### A.2.3 Tests applicable to buffered optical fibres + +##### A.2.3.1 Dimensions + +The outer diameter of all types of fibre secondary coatings (buffers) should comply with [IEC 60794-3] or with the DS. The diameter tolerance should comply with [IEC 60794-3]. + +Measurements should be performed using [IEC 60793-1-21] or [IEC 60811-203]. + +##### A.2.3.2 Buffer strippability + +Buffers should be strippable in a manner consistent with their intended method of connectorization or splicing. + +Buffers should be capable of being stripped using the parameters as shown in Table A.9. Stripping methods and measurements should be performed according to [IEC 60794-1-21] method E5C. + +**Table A.9 – Strip lengths and forces for buffer strippability test** + +| Buffer type | Material stripped | Strip length | Strip force | +|-----------------------------|---------------------------------------------|--------------------|---------------| +| Tight | Remove buffer and primary coating as a unit | 15 mm $\pm$ 1.5 mm | 1.3 N to 13 N | +| Semi-tight | Remove buffer, primary coating intact | 15 mm $\pm$ 1.5 mm | < 13 N | +| Easily-removable semi-tight | Remove buffer, primary coating intact | 150 mm | as agreed | + +#### A.2.4 Tests applicable to buffer tubes + +##### A.2.4.1 Dimensions + +Buffer tube dimensions should be according to the DS or as agreed between the manufacturer and the customer. + +For measuring buffer tubes the methods of [IEC 60811-202] and [IEC 60811-203] should be used. + +##### A.2.4.2 Tube kink + +Tube kinking characteristics and testing should be according to [IEC 60794-3-11]. + +For measuring kink characteristics of tubes, [IEC 60794-1-23] method G7 should be used. + +#### A.2.5 Tests applicable to ribbons + +Testing of fibre ribbons should be according to [IEC 60794-1-31] and [IEC 60794-3-11]. + +##### **A.2.5.1 Dimensions** + +Fibre ribbon dimensions should be according to [IEC 60794-1-31], Table 1. Ribbon dimensions should be measured according to [IEC 60794-1-31]. + +##### **A.2.5.2 Separability of individual fibres from a ribbon** + +Separability of individual fibres from a ribbon should be according to [IEC 60794-1-31]. + +##### **A.2.5.3 Ribbon strippability** + +Strippability of ribbons, as a whole or in units should be according to [IEC 60794-1-310] and as follows. + +At least 25 mm of the matrix and the fibres' protective coatings should be removable with commercially available stripping tools from aged and unaged ribbons. There should be no fibre breakage. Any remaining coating residue should be readily removable using isopropyl alcohol wipes. Ribbon ageing is under study. Stripping force should be measured using [IEC 60793-1-32] as applicable to the multiple fibres in a ribbon. + +#### **A.2.6 Cable element measurements** + +##### **A.2.6.1 Dimensions** + +Dimensions for other tubes, slotted cores, micro-modules, other ruggedized fibres, strength members, jackets, or other cable elements should be as agreed between the manufacturer and the customer. + +Measurement of these cable elements should use methods [IEC 60811-202] and [IEC 60811-203], as applicable. + +##### **A.2.6.2 Cable diameter** + +The cable outer diameter should not exceed the maximum stated by the manufacturer in accordance with [IEC 60794-3-11]. + +The measurement should be in accordance with [IEC 60811-203]. + +##### **A.2.6.3 Sheath thickness** + +The sheath thickness of duct and tunnel cable should be in accordance with [IEC 60794-3-11], or as alternately agreed between the manufacturer and customer. + +Measurement should be in accordance with [IEC 60811-203]. + +##### **A.2.6.4 Moisture barrier adhesion** + +If a moisture barrier tape is used, it should be in accordance with [IEC 60794-3-11]. + +The adhesion of the tape to the sheath should be tested in accordance with [IEC 60708]. + +### **A.3 Test methods for mechanical characteristics of the cable** + +This clause recommends appropriate tests and test methods for verifying the mechanical characteristics of duct and tunnel cables. + +Performance and acceptance criteria and testing should comply with [IEC 60794-3] and [IEC 60794-3-11] and the clauses below. Testing should be done according to [IEC 60794-1-21] and its subordinate specifications. + +In many cases, visual examination of a duct or tunnel cable during or after testing is appropriate. + +Visual examination of cables should be done using normal or normal corrected vision. Examination using magnification is needed. This provides the most effective combination of enlargement and depth-of-field. + +#### A.3.1 Tensile strength + +This test method applies to duct and tunnel cables installed under all environmental conditions. Measurements are made to examine the behaviour of the fibre attenuation and fibre strain as a function of the load on a cable during installation and during its lifetime. + +The cable should perform in accordance with [IEC 60794-3-11], using the criteria below. + +The rated tensile load, also termed short-term load, tensile rating of a cable ( $L_S$ ), should be the nominal value consistent with the tensile load ratings of clause 6.2.2.1. The residual load, or long-term load, $L_L$ , should be 30% of $L_S$ , as per clause 6.2.2.1. + +A tensile rating above $L_S$ may be declared by the manufacturer. But the testing should be carried out at the rated tensile load. + +The maximum changes in the attenuation should be: + +- Attenuation changes should not be specified at $L_S$ , as this is a short term load event. +- There should be no change in the attenuation at $L_L$ and after removal of the load; see clause A.1.3. + +The fibre strain under load should be: + +- $\leq 60\%$ of the fibre proof strain under load $L_S$ ; +- $\leq 20\%$ of the fibre proof strain under load $L_L$ , for fibres proof tested at 1% strain; or $\leq 17\%$ of the fibre proof strain under load $L_L$ , for fibres proof tested at greater than 1% up to 2% strain. + +The test should be carried out in accordance with [IEC 60794-1-21] method E1. + +There should be no damage to the sheath or cable elements under visual examination. + +#### A.3.2 Bending + +This test method applies to duct and tunnel cables installed under all environmental conditions. + +The purpose of this test is to determine the ability of optical fibre cables to withstand coiling or bending around a pulley, that is simulated by a test mandrel. + +The cable should perform in accordance with [IEC 60794-3-11]. + +This test should be carried out in accordance with [IEC 60794-1-21] method E11. The bending diameter should be according to clause 6.2.3.1. The mandrel or sheave diameter should be $\pm 10\%$ of the specified value. + +#### A.3.3 Bending under tension + +This test method applies to duct and tunnel cables installed under all environmental conditions. + +The purpose of this test is to determine the ability of an optical fibre cable to withstand bending around rollers or bows during installation, when a specified load is applied. + +This test should be carried out in accordance with [IEC 60794-1-21] method E18A, procedure 2: + +- tension: cable rated tensile load, $L_S$ ; +- length of cable tested in the bend: +distance required for the circuit between the roller/sheave exits, plus 10 m; +- length of cable/end preparation: +no end preparation is required for cable lengths of 100 m or greater +cable elements fixed together at either end for cable lengths less than 100 m; + +- radius of rollers/sheaves, $R$ : $1/2 \times (20 \times d \text{ or } 40 \times d, \text{ per clause 6.2.3.1}), \pm 10\%$ ; +- bending angle, $\theta$ : between $90^\circ$ and $135^\circ$ ; +- number of cycles: 3. + +There should be no change in the attenuation after the test. + +There should be no visible cracking of the sheath components when removed successively and examined. + +#### A.3.4 Repeated bending + +This test method applies to duct and tunnel cables installed under all environmental conditions. + +The purpose of this test is to evaluate the ability of optical fibre cables to undergo repeated bending associated with normal handling and service. + +The cable should perform in accordance with [IEC 60794-3-11], and tested in accordance with [IEC 60794-1-21] method E6 with the following criteria: + +- mandrel radius, $r$ : $1/2 \times 20 d$ (per clause 6.2.3.1), with a minimum value of 150 mm, $\pm 10\%$ . + +The maximum increase in the attenuation during the test should be: + +- $\leq 0.15 \text{ dB}$ at 1 550 nm for single-mode fibres. + +There should be no change in the attenuation after the test. + +There should be no visible cracking of any armour or shield greater than 5 mm in length. Inspection should be performed using $5 \times$ magnification. There should be no visible damage to the other cable elements. + +#### A.3.5 Crush + +This test method applies to duct and tunnel cables installed under all environmental conditions. + +The appropriate test method for most terrestrial cables is the plate-plate crush method. + +The cable should perform in accordance with [IEC 60794-3-11], and tested in accordance with [IEC 60794-1-21] method E3A using the following criteria: + +- Short term test segment – load applied for 1 minute; +- Long term test segment – load applied for 10 minutes; +- Plate/plate loads, per [IEC 60794-3-11] as shown in Table A.10; +- Measure attenuation at the end of the long term loading, before releasing the load. + +There should be no change in attenuation at the end of the long term loading. + +**Table A.10 – Plate/plate loads for crush test** + +| | Short term | Long term | +|------------------|------------|-----------| +| Unarmoured cable | 1.5 kN | 0.75 kN | +| Armoured cable | 2.2 kN | 1.1 kN | + +#### A.3.6 Impact + +This test method applies to duct and tunnel cables installed under all environmental conditions. + +The purpose of this test is to evaluate the ability of optical fibre cables to survive impacts associated with normal installation and handling. + +The cable should perform in accordance with [IEC 60794-3-11], and tested in accordance with [IEC 60794-1-21] method E4 using the following criteria: + +- Use the standard, flat hammer (300 mm minimum face radius); +- Strike the cable 1 time in each of 3 different places, spaced not less than 150 mm $\pm$ 15 mm apart; +- Use an impact energy of: +10 J for non-armoured cable; +20 J for armoured cable. + +#### **A.3.7 Torsion** + +This test method applies to duct and tunnel cables installed under all environmental conditions. + +The purpose of this test is to evaluate the ability of optical fibre cables to accommodate torsion associated with normal installation and handling. + +The cable should perform in accordance with [IEC 60794-3-11], and tested in accordance with [IEC 60794-1-21] method E7 using the following criteria: + +- Length under test: 2 m; +- Sample rotation: 180° in each direction; +- 5 cycles. + +NOTE – Different sample lengths and rotations equivalent to 90°/m may be used. + +After the test, there should be no change in the attenuation. + +#### **A.3.8 Abrasion of cable printing** + +This test method applies to duct and tunnel cables installed under all environmental conditions. + +The purpose of this test is to evaluate the permanence of cable printing. + +The cable should perform in accordance with [IEC 60794-3-11] and tested in accordance with [IEC 60794-1-21] method E2A, method 2. This method tests the print using the felt pad method. + +After the test, the cable printing should still be legible. + +#### **A.3.9 Kink** + +This test method applies to duct and tunnel cables installed under all environmental conditions. + +The purpose of this test is to evaluate the ability of optical fibre cables to undergo normal handling without kinking. + +This test should be carried out in accordance with [IEC 60794-1-21] method E10. The test criteria should be: + +- Test 1 sample; +- Perform the test at ambient temperature. + +The cable should not kink at a loop diameter greater than the cable minimum bend diameter (see clause 6.2.3.1). There should be no attenuation requirement. + +#### **A.3.10 Vibration** + +Vibration testing should be as agreed between the manufacturer and the customer (see clause 6.2.7). + +Vibration testing per [IEC 60794-1-21], method E19 aeolian vibration, or method E26 galloping, is generally not applicable to duct and tunnel cables. + +### **A.4 Test methods for environmental characteristics** + +This clause recommends the appropriate tests and test methods for verifying the environmental characteristics of duct and tunnel cables. + +Performance and acceptance criteria and testing should comply with [IEC 60794-3] and [IEC 60794-3-11] and the clauses below. Testing should be done according to [IEC 60794-1-2] and its subordinate specifications. + +Appropriate temperature ranges for duct and tunnel cables are shown in clause 6.3.2, Table 1. Unless other temperature ranges are specified for particular applications, the values in Table 1 should be used. + +#### **A.4.1 Temperature cycling** + +This test method applies to duct and tunnel cables installed under all environmental conditions. + +Testing is carried out by temperature cycling to determine the stability of the attenuation of a cable due to temperature changes which may occur during operation. + +The cable should perform in accordance with [IEC 60794-3-11] and tested in accordance with [IEC 60794-1-2] method F1 at the operational temperature per clause 6.3.2, Table 1. These temperatures are $T_{A2}$ and $T_{B2}$ of method F1. Other temperature values or intermediate values in method F1 should be as agreed between the manufacturer and the customer. + +Attenuation changes at all temperatures should be calculated as deviations from the value at the initial measurement at ambient temperature. + +There should be no change in the attenuation at ambient temperature after the test. + +#### **A.4.2 Ageing** + +This test method applies to duct and tunnel cables installed under all environmental conditions. + +The purpose of this test is to evaluate the reaction of cable components under simulated ageing by applying a high temperature to accelerate ageing. + +This test should be carried out in accordance with [IEC 60794-1-2] method F9, usually as an extension of the temperature cycling test of clause A.4.1. + +Attenuation changes at the end of the ageing period should be calculated as deviations from the value at the initial ambient for this test. If this test is carried out as an extension of the temperature cycling test, the initial ambient point for ageing is at the end of the temperature cycling test. Unless otherwise specified, the attenuation change at the end of the test should be: + +- 0.25 dB/km maximum, and 0.10 dB/km average, at 1 550 nm for single-mode fibres. + +#### **A.4.3 Longitudinal water penetration** + +This test method applies to water-blocked outdoor cables installed under all environmental conditions. + +The intention is to check that all the interstices of a cable are sufficiently filled with a compound or water blocking material to prevent water penetration within the cable. + +The cable should perform in accordance with [IEC 60794-3-11]. Testing should be carried out in accordance with [IEC 60794-1-2] method F5B or [IEC 60794-1-2] method F5C, as appropriate to the design. + +There should be no leakage at the end of the cable after 24 hours in the test or retest, as per [IEC 60794-1-2] method F5. + +#### **A.4.4 Moisture permeation** + +This test method applies to duct and tunnel cables installed under all environmental conditions. + +This test applies to cables supplied with a longitudinal overlapped metallic foil. The moisture permeation can be tested according to the test method as described in Chapter 2 of [b-ITU-T TR.ofcs]. + +Requirements should be agreed upon between the manufacturer and the customer. + +#### **A.4.5 Pneumatic resistance** + +If a gas pressurization system is used to protect non-water-blocked duct or tunnel optical fibre cables, this test may be appropriate. + +The purpose of this test is to ensure that an adequate amount of gas flow will pass through the cable. + +This test should be carried out in accordance with [IEC 60794-1-2] method F8. The specimen length and maximum pneumatic resistance should be according to a detailed specification (DS) agreed between the manufacturer and the customer. + +If the intent is to provide gas blocking in a cable, the referenced test method should be used with minimum pneumatic resistance criteria as agreed between the manufacturer and the customer. + +#### **A.4.6 Freezing** + +Freezing testing comprises two related test methods which is applicable to optical fibre cables installed under environmental conditions in which the freezing of the ground surrounding the cable or duct containing the cable may occur. The cases are a cable within a duct buried directly in the ground or similarly surrounded by a medium which can freeze, and a cable in a buried duct which is subject to water intrusion. The latter is of most usefulness for duct and tunnel cables (see clause 6.3.6). + +##### **A.4.6.1 Freezing in an unconfined space** + +This test is not often used for duct and tunnel cables. The purpose of the external freezing test is to simulate the freezing of the medium surrounding a buried cable, as in wet earth or water. It is not intended to simulate the freezing of a cable in a duct or pipe (see clause 6.3.6 for the applicability of this test). It may be useful for evaluating duct and tunnel cables not normally intended for outdoor installation. + +This test should be carried out in accordance with method [IEC 60794-1-215] method F15A. + +Unless otherwise specified, the allowable change in attenuation when the cable is frozen should be: + +- $\leq 0.15$ dB/km at 1 550 nm. + +**Unless otherwise specified, there should be no change in the attenuation at the ambient temperature after the test.** + +##### **A.4.6.2 Freezing of cable in a duct** + +The purpose of the external freezing test for the cable within a duct is to simulate freezing of the medium surrounding a buried duct or freezing temperatures affecting an aerial duct containing a cable or cables into which water might collect and surround the cable (see clause 6.3.6 for the applicability of this test). In applications where water intrusion into a rigid duct is considered, it is common to install cables along with pressure absorbing elements within the duct. The intent of this test is to evaluate the assembly of the cable and pressure absorber elements if any, and the duct when frozen. + +This test should be carried out in accordance with method [IEC 60794-1-215] method F15B. + +Unless otherwise specified, the allowable change in attenuation when the cable is frozen should be: + +- $\leq 0.15$ dB/km at 1 550 nm. + +**Unless otherwise specified, there should be no change in the attenuation at the ambient temperature after the test.** + +#### **A.4.7 Material compatibility** + +This test method applies to duct and tunnel cables installed under all environmental conditions in accordance with [IEC 60794-1-219]. This test may apply to all duct and tunnel cables, but particularly applies to cables using polymeric gels or flooding compounds. Cables not utilizing the above should be tested as agreed between manufacturer and user, following the intent of this clause. + +This test method is intended to ensure compatibility of the cable materials (e.g., fibres, plastics, water blocking materials, and metals) over the cable's lifetime. The procedure simulates lifetime exposure by ageing a whole-cable specimen or selected elements of a cable at an elevated temperature over a period of time. Fibre and buffered fibre compatibility testing is addressed in clauses A.2.1 and A.2.3, which may be done in conjunction with this test. + +##### **A.4.7.1 Procedure for ageing** + +Ageing of completed cable specimens is under study. Control specimens for "before ageing" comparison or testing should be maintained. + +After ageing, the components should be removed from the cable or element assemblies and tested as follows. + +##### **A.4.7.2 Jacket tensile strength and elongation testing – after ageing** + +Jacket material tensile and elongation should be tested in accordance with [IEC 60811-501]. The aged jacket shall retain a minimum of 75% of its unaged tensile strength and elongation values. + +##### **A.4.7.3 Metal coatings delamination testing – after ageing** + +Plastic coatings on metal tapes should show no visual evidence of delamination. + +#### **A.4.8 Oxidative induction time, OIT – for polyolefin filling and jacket materials** + +Filling compounds and polyolefin-base jacket materials in all duct and tunnel cables installed in all environmental conditions should be tested to assess the level of stabilization of the material. The oxidative induction time (OIT) test performs such an assessment using differential scanning calorimetry (DSC) techniques. + +The mass of the specimen should be per [ISO 11357-6]. A filling compound sample may be either from incoming material or from a finished cable. Jacket material should be from a finished cable or specifically manufactured simulated cable jackets. + +The specimen should be tested per [ISO 11357-6] with the following modifications and clarifications: + +- For filling the compound – the test temperature should be $190^{\circ}\text{C} \pm 0.5^{\circ}\text{C}$ ; +- For polyolefin jacket material – the test temperature should be $199^{\circ}\text{C} \pm 1^{\circ}\text{C}$ ; +- The rate of heating of the test sample should be $10^{\circ}\text{C}/\text{minute}$ ; +- An aluminium pan should be used in place of the copper crucible (pan); +- Screens should not be used; +- The torque rheometer is not required. + +The minimum OIT should be 20 minutes for filling compound or jacket material. + +#### **A.4.9 Hydrogen** + +This test rarely applies to duct and tunnel cables. This test method applies to optical fibre cable installed in a submarine environment or in higher atmospheric pressure applications. In the unusual + +case where a duct or tunnel cable resides in a hermetically sealed duct, hydrogen testing may be considered. + +In the case of a metal-free cable or one employing a moisture barrier sheath with a selection of cable components that are low in the generation of hydrogen, either by themselves or in combination with others (for example, water), the build-up of hydrogen gas within the cable core will not lead to a significant increase in optical loss. + +For other cable constructions, [ITU-T L.126] and [b-IEC TR 62690] should be consulted. + +#### **A.4.10 Nuclear radiation** + +This test method assesses the suitability of optical fibre cables to be exposed to nuclear radiation. + +This test should be carried out in accordance with [IEC 60794-1-2] method F7. + +#### **A.4.11 Cable sheath adherence** + +This test applies to duct and tunnel cables installed under all environmental conditions. A range of installation techniques can apply a frictional force to the outer jacket, which may cause the jacket to slip with respect to the underlying cable – either in tension or compression. + +The test is applicable to cables in which the jacket is not adhesively bonded to the underlying cable structure. Generally, these are dielectric or metallic cables without strength members in the jacket or armoured cables, all with flooding compounds applied over the inner structure or the shield or armour. Cables that are not water blocked are also subject to this test. Cables using a bonded armour construction are not tested due to the inherently high longitudinal bond strength of such constructions. + +The test measures the resistance of the cable sheath components (shield or armour and the overlaying jacket) to separation, one from another, by measuring the force required to pull the cable core and metallic covering out of the jacket. + +Cables should be tested according to [IEC 61196-1-313] or following the intent, as modified below. The test should be at expanded ambient temperature per clause A.1.4. + +##### **A.4.11.1 Test procedure** + +In using the terminology of the referenced test method, the "conductor" or "outer conductor" should be the core assembly without the jacket. The "dielectric" or "sheath" should be the cable jacket. + +The tested specimen should be of sufficient length to provide the test length of $300 \text{ mm} \pm 15 \text{ mm}$ , per Figure A.1, and the prepared length of the core and jacket. The prepared lengths of the core and split jacket should be a length convenient for testing, generally about 100 mm each. The test may also be performed using the test plate of the referenced test rather than preparing the jacket. + +The test should be performed per [IEC 61196-1-313], as shown in Figure A.1, for illustration. + +![Diagram of the sheath adherence test apparatus and sample. A cable sample is shown with its outer sheath peeled back at an angle. The inner core is held by a 'Knurled mandrel' at the top, with an upward force 'F' applied. The bottom of the cable sample is held by a 'Clamp', with a downward force 'F' applied. A vertical dimension line indicates a length of '300 mm (12 inches)' between the mandrel and the clamp. The diagram is labeled 'L:100(21)_FA.1' at the bottom right.](19fd552435a80d0ffda518b710d16908_img.jpg) + +Diagram of the sheath adherence test apparatus and sample. A cable sample is shown with its outer sheath peeled back at an angle. The inner core is held by a 'Knurled mandrel' at the top, with an upward force 'F' applied. The bottom of the cable sample is held by a 'Clamp', with a downward force 'F' applied. A vertical dimension line indicates a length of '300 mm (12 inches)' between the mandrel and the clamp. The diagram is labeled 'L:100(21)\_FA.1' at the bottom right. + +**Figure A.1 – Sheath adherence test apparatus and sample** + +##### A.4.11.2 Requirements + +The sheath adherence should have a value greater than 14 N/mm of the circumference of the inner surface of the jacket. That circumference is most conveniently measured as the outer circumference of the armour, shield, or underlying cable structure. + +### A.5 Test methods for biotic characteristics + +#### A.5.1 Biotic damage + +##### A.5.1.1 Rodent and insect damage + +Testing for resistance of duct and tunnel cable to damage from rodents or insects should be as agreed between the manufacturer and customer (see clause 6.5). + +##### A.5.1.2 Fungus resistance of jackets + +Fungus evaluation is applicable to cables installed in all environmental conditions. Polyethylene jacket materials commonly used in duct and tunnel cables are inherently non-nutritive to fungus. Other jacket materials, including those which may be applied for fire rated cables or as outer jackets, may require evaluation for fungus resistance. + +The test methods and requirements should be as agreed between the manufacturer and the user. [ITU-T L.161] may be consulted for guidance. Test methods for assessing fungus resistance are under development in IEC. + +### A.6 Test methods for electrical characteristics + +#### A.6.1 Lightning + +While of secondary importance to duct and tunnel cables, lightning testing should be considered (see clause 6.6.1). + +When a metallic material is used as a cable element, the lightning protection of a cable may undergo a test described in [ITU-T K.47], subject to agreement between the customer and the manufacturer. + +#### **A.6.2 Electrical continuity** + +The electrical continuity test is to verify that cable metallic elements are electrically continuous throughout the cable. This test is important for bonding and grounding, toning for location, and other related system issues. Typically, the test should check continuity and should carry no resistance or conductivity requirement. The metallic elements may be tested individually or may be tested as a total group. Since this latter criterion is frequently the case, all elements are to be measured as a group unless specified otherwise. + +The test should be performed per [IEC 60794-1-403]. All metallic elements on the test should be electrically continuous. + +# Bibliography + +- [b-ITU-T G Suppl.40] Supplement 40 to ITU-T G-series Recommendations (2018), *Optical fibre and cable Recommendations and standards guideline*. +- [b-ITU-T TR.ofcs] ITU-T Technical Report TR-OFCS (2015), *Optical fibres, cables and systems*. +<> +- [b-IEC TR 62222] IEC TR 62222:2021, *Fire performance of communication cables installed in buildings*. +<> +- [b-IEC TR 62690] IEC TR 62690:2014, *Hydrogen effects in optical fibre cables – Guidelines*. +<> +- [b-IEC TR 62691] IEC TR 62691:2016, *Optical fibre cables – Guidelines to the installation of optical fibre cables*. +<> +- [b-IEC TR 63194] IEC TR 63194:2019, *Guidance on colour coding of optical fibre cables*. +<> + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|----------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1000-201907-I_PDF-E/4801720824e4b5e2361a5564f91cfb70_img.jpg b/marked/L/T-REC-L.1000-201907-I_PDF-E/4801720824e4b5e2361a5564f91cfb70_img.jpg new file mode 100644 index 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It features a blue circular emblem with a stylized globe and the letters 'ITU' in white. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +### **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|--------------------------------------------------------|--------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.101 + +# **Optical fibre cables for directly buried application** + +## **Summary** + +Recommendation ITU-T L.101 describes characteristics, construction and test methods of optical fibre cables for buried application. + +Note that Recommendation ITU-T L.43, Ed 2.0, was redesignated as ITU-T L.101, Ed 2.0, in February 2016. + +First, in order to demonstrate sufficient performance of an optical fibre cable, the characteristics that a cable should possess are described in this Recommendation. Methods of examining whether a cable has the required characteristics are then described and detailed performance criteria for a cable are recommended. + +Recommended technical requirements are detailed by reference to IEC 60794-3-11 on outdoor optical fibre cables for duct, directly buried, and lashed aerial applications. Changes and additions to these requirements suitable to the directly buried cable application are also recommended herein. + +Required conditions may differ from the installation environment. Therefore, instances where agreement on detailed conditions should be determined between customer and manufacturer are stated. + +This version of Recommendation ITU-T L.101 adds the electrical continuity test for continuous metallic elements. The scope, references, fibre dimensions, Annex A, and the bibliography are also updated. + +## **History\*** + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|------------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.43 | 2002-12-22 | 6 | 11.1002/1000/6138 | +| 2.0 | ITU-T L.101/L.43 | 2015-08-13 | 15 | 11.1002/1000/12531 | +| 3.0 | ITU-T L.101 | 2024-08-29 | 15 | 11.1002/1000/16038 | + +## **Keywords** + +Buried cabling, cable structure, cable testing, optical fibre cable. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, and information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2024 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|-----------|----------------------------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 3 | +| 3.1 | Terms defined elsewhere ..... | 3 | +| 3.2 | Terms defined in this Recommendation..... | 4 | +| 4 | Abbreviations and acronyms ..... | 4 | +| 5 | Conventions ..... | 4 | +| 6 | Characteristics of optical fibres and cables ..... | 4 | +| 6.1 | Optical fibre characteristics..... | 4 | +| 6.2 | Mechanical characteristics..... | 5 | +| 6.3 | Environmental characteristics ..... | 7 | +| 6.4 | Biotic damage..... | 10 | +| 6.5 | Electrical characteristics..... | 10 | +| 7 | Cable construction ..... | 11 | +| 7.1 | Fibre coatings ..... | 11 | +| 7.2 | Cable elements..... | 11 | +| 7.3 | Sheath and jacket..... | 15 | +| 7.4 | Armour ..... | 15 | +| 7.5 | Identification of cable..... | 15 | +| 7.6 | Cable sealing ..... | 16 | +| Annex A – | Test methods..... | 17 | +| A.1 | Standard test criteria ..... | 20 | +| A.2 | Test methods for cable elements ..... | 21 | +| A.3 | Test methods for mechanical characteristics of the cable ..... | 23 | +| A.4 | Test methods for environmental characteristics ..... | 27 | +| A.5 | Test methods for biotic characteristics ..... | 31 | +| A.6 | Test methods for electrical characteristics ..... | 31 | +| | Bibliography..... | 32 | + + + +# Recommendation ITU-T L.101 + +## Optical fibre cables for directly buried application + +# 1 Scope + +Optical fibre cables are traditionally used in trunk line networks, but their use is expanding rapidly to access networks. Today, many cables are buried in order to respect the environmental landscape, to reduce network construction costs or to reduce the need for extension of underground facilities such as ducts and tunnels. + +When installed without ducts, tunnels and hard protection, cables should have good resistance characteristics to harsh conditions. Some cables have strong outer armouring, others have outer pipe-systems or special plastic sheaths. + +This Recommendation: + +- refers to single-mode optical fibre cables to be used for telecommunication networks in directly buried installations; +- considers the mechanical and environmental characteristics of the optical fibre cables. The optical fibre dimensional and transmission characteristics, should comply with one or more of: [ITU-T G.652], [ITU-T G.653], [ITU-T G.654], [ITU-T G.655], [ITU-T G.656], [ITU-T G.657] and [IEC 60793-2-50]; +- considers fundamental aspects related to optical fibre cable from mechanical and environmental points of view; +- refers to the technical specifications of [IEC 60794-3-11] as applicable to optical fibre cables for buried application; +- recommends performance criteria for those tests that are relevant to the directly buried application space. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T G.650.1] Recommendation ITU-T G.650.1 (2024), *Definitions and test methods for linear, deterministic attributes of single-mode fibre and cable*. +- [ITU-T G.650.2] Recommendation ITU-T G.650.2 (2015), *Definitions and test methods for statistical and non-linear related attributes of single-mode fibre and cable*. +- [ITU-T G.650.3] Recommendation ITU-T G.650.3 (2017), *Test methods for installed single-mode optical fibre cable links*. +- [ITU-T G.652] Recommendation ITU-T G.652 (2024), *Characteristics of a single-mode optical fibre and cable*. +- [ITU-T G.653] Recommendation ITU-T G.653 (2010), *Characteristics of a dispersion-shifted single-mode optical fibre and cable*. + +- [ITU-T G.654] Recommendation ITU-T G.654 (2024), *Characteristics of a cut-off shifted single-mode optical fibre and cable.* +- [ITU-T G.655] Recommendation ITU-T G.655 (2009), *Characteristics of a non-zero dispersion-shifted single-mode optical fibre and cable.* +- [ITU-T G.656] Recommendation ITU-T G.656 (2010), *Characteristics of a fibre and cable with non-zero dispersion for wideband optical transport.* +- [ITU-T G.657] Recommendation ITU-T G.657 (2024), *Characteristics of a bending-loss insensitive single-mode optical fibre and cable.* +- [ITU-T K.29] Recommendation ITU-T K.29 (1992), *Coordinated protection schemes for telecommunication cables below ground.* +- [ITU-T K.47] Recommendation ITU-T K.47 (2012), *Protection of telecommunication lines against direct lightning flashes.* +- [ITU-T L.126] Recommendation ITU-T L.126/L.27 (1996), *Method for estimating the concentration of hydrogen in optical fibre cables.* +- [ITU-T L.161] Recommendation ITU-T L.161/L.46 (2000), *Protection of telecommunication cables and plant from biological attack.* +- [IEC 60304] IEC 60304 (1982), *Standard colours for insulation for low-frequency cables and wires.* +- [IEC 60331-25] IEC 60331-25 (1999), *Tests for electric cables under fire conditions – Circuit integrity – Part 25: Procedures and requirements – Optical fibre cables.* +- [IEC 60332-1-2] IEC 60332-1-2 (2004), *Tests on electric and optical fibre cables under fire conditions – Part 1-2: Test for vertical flame propagation for a single insulated wire or cable – Procedure for 1 kW pre-mixed flame.* +- [IEC 60332-3-24] IEC 60332-3-24 (2018), *Tests on electric and optical fibre cables under fire conditions – Part 3-24: Test for vertical flame spread of vertically-mounted bunched wires or cables – Category C.* +- [IEC 60708] IEC 60708 (2005), *Low-frequency cables with polyolefin insulation and moisture barrier polyolefin sheath.* +- [IEC 60793-1-21] IEC 60793-1-21 (2001), *Optical fibres – Part 1-21: Measurement methods and test procedures – Coating geometry.* +- [IEC 60793-1-32] IEC 60793-1-32 (2018), *Optical fibres – Part 1-32: Measurement methods and test procedures – Coating strippability.* +- [IEC 60793-1-40] IEC 60793-1-40 (2019), *Optical fibres – Part 1-40: Attenuation measurement methods.* +- [IEC 60793-2-50] IEC 60793-2-50 (2018), *Optical fibres – Part 2-50: Product specifications – Sectional specification for class B single-mode fibres.* +- [IEC 60794-1-1] IEC 60794-1-1 (2023), *Optical fibre cables – Part 1-1: Generic specification – General.* +- [IEC 60794-1-2] IEC 60794-1-2 (2021), *Optical fibre cables – Part 1-2: Generic specification – Cross references table for optical cable test procedures.* +- [IEC 60794-1-21] IEC 60794-1-21 (2015), *Optical fibre cables – Part 1-21: Generic specification – Basic optical cable test procedures – Mechanical tests methods.* + +- [IEC 60794-1-22] IEC 60794-1-22 (2012), *Optical fibre cables – Part 1-22: Generic specification – Basic optical cable test procedures – Environmental tests methods* +- [IEC 60794-1-23] IEC 60794-1-23 (2019), *Optical fibre cables – Part 1-23: Generic specification – Basic optical cable test procedures – Cable element test methods.* +- [IEC 60794-1-31] IEC 60794-1-31 (2021), *Optical fibre cables – Part 1-31: Sectional Specification for cable element – Optical fibre ribbons.* +- [IEC 60794-1-215] IEC 60794-1-215 (2020), *Optical fibre cables – Part 1-215: Generic specification – Basic optical cable test procedures – Environmental test methods – Cable external freezing test, Method F15.* +- [IEC 60794-1-219] IEC 60794-1-219 (2021), *Optical fibre cables – Part 1-219: Generic specification – Basic optical cable test procedures – Material compatibility test, Method F19.* +- [IEC 60794-1-310] IEC 60794-1-310 (2022), *Optical fibre cables – Part 1-310: Generic specification – Basic optical cable test procedures – Cable element test methods – Strippability, method G10.* +- [IEC 60794-1-403] IEC 60794-1-403 (2021), *Optical fibre cables – Part 1-403: Generic specification – Basic optical cable test procedures – Electrical test methods – Electrical continuity test of cable metallic elements, Method H3.* +- [IEC 60794-3] IEC 60794-3 (2022), *Optical fibre cables – Part 3: Outdoor cables – Sectional specification.* +- [IEC 60794-3-11] IEC 60794-3-11 (2010), *Optical fibre cables – Part 3-11: Outdoor cables – Product specification for duct, directly buried, and lashed aerial single-mode optical fibre telecommunication cables.* +- [IEC 60811-202] IEC 60811-202 (2012), *Electric and optical fibre cables – Test methods for non-metallic materials – Part 202: General tests – Measurement of thickness of non-metallic sheath.* +- [IEC 60811-203] IEC 60811-203 (2012), *Electric and optical fibre cables – Test methods for non-metallic materials – Part 203: General tests – Measurement of overall dimensions.* +- [IEC 60811-501] IEC 60811-501 (2012), *Electric and optical fibre cables – Test methods for non-metallic materials – Part 501: Mechanical tests – Tests for determining the mechanical properties of insulating and sheathing compounds.* +- [IEC 61196-1-313] IEC 61196-1-313 (2009), *Coaxial communication cables – Part 1-313: Mechanical test methods – Adhesion of dielectric and sheath.* +- [ISO 11357-6] ISO 11357-6 (2018), *Plastics – Differential scanning calorimetry (DSC) – Part 6: Determination of oxidation induction time (isothermal OIT) and oxidation induction temperature (dynamic OIT).* + +# **3 Definitions** + +## **3.1 Terms defined elsewhere** + +For the purpose of this Recommendation, the definitions given in [ITU-T G.650.1], [ITU-T G.650.2], and [ITU-T G.650.3], and [IEC 60794-1-1] apply. + +Other terms used, particularly in referencing IEC test procedures and specifications, are per [IEC 60794-1-1] and other IEC specifications specifically referenced. + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 cable weight (W):** Force (N) exerted from the weight of 1 km of the cable that is suspended vertically. + +**3.2.2 jacket:** One or more polymer coverings comprising the main protection of the fibre cable as part of a sheath; inner jackets or outer jackets may be used, as necessary. + +**3.2.3 sheath:** An assembly of cable elements surrounding and protecting the fibre core; including, but not limited to, jacket(s), strength member(s), armour(s), moisture barrier(s), etc. as necessary. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|----------------|-------------------------------------------------------------------------------------------------------| +| BoL | Beginning of Life, as applied to cable testing and criteria | +| d | Outer diameter, as of a cable, core tube, or other element described in the usage (see clause 6.2.3). | +| DS | Detailed Specification | +| EoL | End of Life, as applied to cable testing and criteria | +| Ls or LM | Tensile rating of a cable | +| Ll | Long-term, or residual, load rating of a cable | +| OD | Outer Diameter | +| OIT | Oxidative Induction Time, as applied to polyolefin materials | +| PE | Polyethylene | +| PVC | Polyvinyl Chloride | +| r or R | Radius of the element described | +| SZ | Reverse oscillating stranding | +| T A | Lower temperature for environmental characteristics | +| T B | Higher temperature for environmental characteristics | +| W | Cable weight | + +## 5 Conventions + +In this Recommendation with respect to the terms 'attenuation' and 'attenuation coefficient', the term 'attenuation' is used, for the sake of brevity and convenience, with the understanding that values on a per length basis – dB/km – are, more correctly, 'attenuation coefficient'. + +# 6 Characteristics of optical fibres and cables + +## 6.1 Optical fibre characteristics + +The following optical fibre types should be considered for use in cables of this Recommendation, based on agreement between manufacturers and customers. Single-mode optical fibres should be used as described in [ITU-T G.652], [ITU-T G.653], [ITU-T G.654], [ITU-T G.655], [ITU-T G.656] or + +[ITU-T G.657]. The corresponding IEC fibre category designations are shown in Appendix V of [b-ITU-T G-Sup.40]. + +#### **6.1.1 Transmission characteristics** + +The typical transmission characteristics are described for each optical fibre in its respective Recommendation. Unless specified otherwise by the users of the Recommendations, those values apply to the corresponding cabled optical fibre. + +The maximum point discontinuity at the operating wavelength(s) for fibres should be in accordance with [IEC 60794-1-1]. + +#### **6.1.2 Fibre microbending loss** + +Severe bending of an optical fibre involving local axial displacement of a few micrometres over short distances, caused by localized lateral forces along its length can result in additional attenuation in the optical fibre and microbending loss. This may be caused by manufacturing and installation strains, and also during operation by dimensional variations of cable materials due to temperature changes. + +Microbending can cause an increase in optical loss. In order to reduce microbending loss, stress randomly applied to a fibre along its axis should be minimized during the incorporation of the fibres into the cable, as well as during and after cable installation. + +#### **6.1.3 Fibre macrobending loss** + +Macrobending is the resulting curvature, typically several mm in radius, of an optical fibre. + +Macrobending of an optical fibre after cable manufacture and installation can cause an increase in optical loss. The optical loss caused by macrobending typically increases as the bending radius is reduced. + +NOTE – ITU-T G.657 optical fibres are optimized for reduced macrobending loss. + +#### **6.1.4 Fibre dimensions** + +Mode-field diameter and cladding diameter are defined by the ITU-T G.65x-series Recommendations. + +The overall fibre dimensions and related characteristics such as non-circularity and concentricity are important in the performance of cabled fibre and in splicing and connectorisation of fibres. Accordingly, [IEC 60793-2-50] specifies critical values and measurement methods. The range of fibre outer coating diameter should be in accordance with [IEC 60793-2-50]. + +## **6.2 Mechanical characteristics** + +#### **6.2.1 Evaluation of mechanical characteristics** + +Cable mechanical characteristics should be evaluated using the test methods and requirements of [IEC 60794-3-11], and applicable recommendations in clause A.3. + +#### **6.2.2 Tensile strength** + +Optical fibre cable is subjected to short-term loading during manufacture and installation, and may be affected by continuous static loading and/or cyclic loading (e.g., temperature variation) during operation. Changes in the tension of the cable due to the variety of factors encountered during the service life of the cable can cause the differential movement of the cable components. This effect should be considered in the cable design. Excessive cable tensile loading may increase the optical loss and may cause increased residual strain in the fibre if the cable cannot relax. When a cable is subjected to permanent loading during its operational life, the fibre should not experience strain beyond values that adversely affect fibre reliability (see clause A.3.1). To avoid these issues, the + +maximum tensile strength determined by the cable construction, especially the design of the strength member, should not be exceeded. + +The standard tensile rating, $L_s$ (or $L_m$ ), of cables per this Recommendation should be: + +$1.5 W$ , where $W$ is the force (N) exerted from the weight of 1 km of the cable that is suspended vertically. + +If the result exceeds 2 700 N, tensile rating should be 2 700 N. + +The long-term tensile rating, $L_L$ , should be 30 per cent of the tensile rating $L_s$ . + +#### 6.2.3 Bending + +Under the dynamic conditions encountered during installation, the fibre is subjected to strain from both cable tension and bending. The strength elements in the cable and the installation bend diameter should be selected to limit this combined dynamic strain. Routing and storage may result in permanent bends after installation. Any fibre bend radius remaining after cable installation should be large enough to limit the macrobending loss or long-term strain limiting the lifetime of the fibre. + +Minimum bending diameter is an important parameter for the physical integrity of the sheath, for fibre strain limitation, and for fibre attenuation performance due to macrobending loss. Cables with smaller core structures can be bent to relatively smaller bend diameters than cables having larger core structures. + +The standard minimum bending diameters for cables should be declared by the manufacturer. Cable bending diameters are defined as: + +- Residual (installed): $20 \times \text{Cable OD}$ or $30 \times \text{Cable OD}$ , +- Loaded condition (during installation): $40 \times \text{Cable OD}$ . + +For very small cables, manufacturers may specify a fixed cable minimum bending diameter that is independent of the cable outer diameter. It should also be noted that the minimum bending diameter changes depending on the cable structure, such as the design and configuration of the strength members. + +NOTE – Some cable tests and specifications declare bending criteria in terms of radius of the apparatus or sheave. Care should be taken to avoid incorrect testing. + +#### 6.2.4 Crush + +A directly buried cable may be subjected to crush both during installation and operational life. Characteristically, the crushing incident involves a relatively short length of the cable. The crushing may be short-term, as during installation, or may be long-term as over the operational life of the cable. + +Cable is constructed to isolate the optical fibres from external compressive forces. The construction and dimensions of the cable affect the resistance of the cable to performance degradation due to crushing. + +Crushing may damage the physical integrity of the cable or may increase the optical loss (either temporarily or permanently). Excessive stress may lead to fibre fracture. + +#### 6.2.5 Impact + +A directly buried cable may be subjected to impact both during installation and operational life. Although in either case the impact is a transient event, still it could result in cable performance deformation and affect the cable over its operational life. + +Cable is constructed to isolate the optical fibres from external compressive forces. The construction and dimensions of the cable affect the resistance of the cable to performance degradation due to impact. + +Impact may damage the physical integrity of the cable or may increase the optical loss (either temporarily or permanently). Excessive stress may lead to fibre fracture. + +Characteristically, impact could cause visible cracks, splits, tears, or other openings on the surface of the cable jacket. + +#### **6.2.6 Torsion** + +Under dynamic conditions encountered during installation and operation, a directly buried cable may be subjected to torsion. This may be under tension during installation and the torsion may remain after the installation is complete. The torsion may be due to coiling of the cable during installation and will often remain over the operational life of the cable. Torsion may result in optical loss of the fibres and/or damage to the sheath including splitting of the sheath. The cable should be sufficiently robust to resist twisting, and its design should accommodate a reasonable number of cable twists per unit length without an increase in optical loss and/or damage to the sheath. + +Characteristically, torsion could cause visible cracks, splits, tears, or other openings on the surface of the cable jacket. + +#### **6.2.7 Vibration** + +Vibration effects on directly buried cables may occur when the cables are installed on structures or in areas where vibrations can be transmitted to the directly buried cable. + +Directly buried optical fibre cable may be subject to persistent vibrations from traffic, railways, etc. or vibrations from infrequent activities such as pile-driving and blasting operations. + +In all cases, cables should withstand these vibrations without failure or performance degradation. + +A well-established surveillance routine can identify the vibration activity, allowing for a careful choice of route to minimize this problem. + +## **6.3 Environmental characteristics** + +#### **6.3.1 Evaluation of environmental characteristics** + +Cable environmental characteristics should be evaluated using the test methods and requirements of [IEC 60794-3-11], and applicable tests methods discussed in clause A.4. + +#### **6.3.2 Temperature variations** + +During their operational lifetime, cables may be subjected to significant temperature variations. In these conditions, the increase of attenuation of the fibres should not exceed the specified limits. + +Directly buried cables will typically experience a less severe range of temperature variations than other outdoor cables. Accordingly, it is necessary to investigate, in advance, the operating temperature range of the location where the cable is to be laid, and to choose a cable design suitable for that environment. + +Cable elements can potentially have different thermal expansion coefficients that can cause differing dimensional changes among the cable elements. This can cause attenuation increases of the optical fibres due to microbending or macrobending effects. Therefore, testing of cables at temperature extremes is recommended. + +Due to the differing behaviours of cable materials at various temperatures, it should be also considered to specify the installation temperature range. Table 1 lists normal temperature ranges appropriate for directly buried cables. + +**Table 1 – Cable normal temperature ranges** + +| Condition | Temperature range | +|-------------------|-----------------------------------------------------------------------------------| +| Operation (°C) | –30 to +60 [IEC 60794-3-11] | +| Installation (°C) | 0 to +50 (PVC sheath) [b-IEC TR 62691]
–15 to +50 (PE sheath) [b-IEC TR 62691] | + +NOTE – Many existing specifications set the lower range limits for operation at –40 °C. Cables tested to these criteria should be considered compliant with the normal ranges above. + +#### 6.3.3 Water penetration + +In the event of damage to the cable sheath or to a splice closure, longitudinal penetration of water in a cable core or between components of the sheath can occur. Several types of problems with the fibre and cable components can occur. + +The presence of water in a cable core diminishes the tensile strength of the fibre, and the average time to static failure is reduced. The degree to which this can occur depends on the performance of the fibre coating, the length of fibre exposed, and the time of exposure. Water migrating to closures on cable ends can have a similar effect on fibres and splices. + +Water present in the cable sheath interstices is generally benign since most of the components are non-reactive to moisture. However, corrosion of metallic components can occur, and galvanic corrosion and production of hydrogen can be accelerated. Reduction in the strength of non-metallic strength members can occur if the materials are susceptible to reactions with moisture. + +Water in the cable may freeze and, under some conditions, can cause fibre crushing which can produce macrobending and microbending that can result in increased optical loss and possible fibre breakage. + +The longitudinal penetration of water should be minimized or, if possible, prevented. In order to prevent longitudinal water penetration within the cable, techniques such as filling the cable core and sheath interstices completely with a compound or with discrete water blocks or swellable components (e.g., tapes, yarns, powders) should be used. In the case of unfilled cables, dry-gas pressurization can be used. Therefore, testing of cables for water penetration is recommended. + +A water penetration test measures the degree to which water may penetrate a specimen of cable that is subjected to a specified water head for a specified period of time. + +#### 6.3.4 Moisture permeation + +Moisture permeates the plastic materials commonly used in cable sheaths at some rate. As with water penetration, when moisture permeates the cable sheath and reaches the cable core, the tensile strength and lifetime of the fibre can be reduced. + +A prime deterrent against moisture damage is performance of the fibre coatings. Various materials can be used as barriers to reduce the rate of moisture permeation through the sheath. A continuous metallic barrier is effective to minimize or prevent moisture permeation; a minimum permeation is achieved by a sealed longitudinal overlapped metallic foil or tape (glued, thermowelded, or welded). In metal-free cables, filling compounds which are effective in preventing longitudinal water propagation, do not significantly hinder radial moisture permeation through plastic sheaths. + +#### 6.3.5 Pneumatic resistance + +Pneumatic resistance of unfilled (air core) cables is an important parameter in systems which use dry-gas pressurization to protect cable cores from moisture. Such systems require some flow of the dry gas to scavenge moisture which enters the pressurized portion of the cable – usually the core or inner jacket structure. To that end, the core must allow passage of the gas under the system design criteria. + +Conversely, cables may pass through a barrier for which gas leakage is to be minimized – environmental containment and watertight bulkheads are examples. Such cables are designed with high pneumatic resistance. + +NOTE – It is intended that a cable can be pressurized only if it allows a flux of air which is in accordance with the criteria defined in chapter 2 of [b-ITU-T TR.ofcs]. + +#### **6.3.6 Freezing** + +##### **6.3.6.1 General** + +Freezing of directly buried cables may occur when the temperature of the ground is below freezing temperature. The maximum expansion of frozen water occurs at $-2 ext{ }^{\circ}\text{C}$ , so extreme conditions are not required for cable freezing. + +Ground with buried cables will frequently be wet, so freezing may occur. + +Water within a cable from moisture permeation or water penetration may be frozen and, under some conditions, can cause fibre crushing with a resultant increase in optical loss and possible fibre breakage. Cable characteristics which address water penetration and moisture permeation can minimize such risks. + +##### **6.3.6.2 External freezing** + +In general, external freezing is only a hazard when the cable is directly installed in ground. This is addressed in clause 6.3.6.3. + +Testing for such conditions is addressed by clause A.4.6. + +##### **6.3.6.3 Freezing in a confined space** + +Directly buried cables are usually not installed in a confined space. + +Freezing of water surrounding an optical cable can cause significant crushing forces due to the restrained expansion of the water as it freezes. In applications where this hazard is expected, installation methods using extremely robust cable designs or pressure absorber elements may be used. Testing for such conditions is addressed by clause A.4.6. + +#### **6.3.7 Ageing** + +Optical cables are designed to have stable performance over many years – typically 20 years or more. Changes in the performance of fibres and cables over their lifetime are very important. End of life (EoL) performance of fibres and cables has proven to be very good, due to accepted and conservative design principles. + +Testing for ageing evaluates the reaction of cable components under simulated ageing by applying high temperatures over extended periods of time. This is not end of life (EoL) testing, but beginning of life (BoL) characterization. The results of such testing may be used to reach agreement between manufacturers and customers. Nonetheless, aspects for performance of cables in simulated ageing are agreed; these are addressed in clause A.4.2. + +#### **6.3.8 Hydrogen gas** + +In the presence of moisture and metallic elements, hydrogen gas may be generated. Hydrogen gas may diffuse into silica glass and increase optical loss. It is recommended that the hydrogen gas concentration in the cable, as a result of its component parts, should be low enough to ensure that the long-term effects on the increase of optical loss are acceptable. The method for estimating the concentration of hydrogen gas in optical cables is given by [ITU-T L.126]. Further information can be found in [b-IEC TR 62690]. + +Fibre design has minimized these effects in the wavelengths used for optical transmission. And, by using dynamic gas pressurization and hydrogen absorbing materials, and by careful material selection and construction, the increase in optical loss can be maintained within acceptable limits over the operational life of the cable. + +#### **6.3.9 Chemical attack** + +After installation, contact with several chemical agents may degrade the cable sheath characteristics, leading to the weakening of the cable core protection. + +To avoid this problem, cable sheath material should be selected carefully, based on its robustness against chemical agents. First of all, it is important to assess what kind of chemical agents may exist in the area where the cable is to be laid. Then, sheath material durability from these chemical agents should be examined. A combination of suitable materials (metallic and non-metallic) can be selected to prevent chemical attack on a cable based on the environmental criteria. + +#### **6.3.10 Mechanical aggression** + +It is difficult to estimate the level of mechanical aggression that the cable may undergo during its handling, installation and maintenance. However, it is clear that a directly buried cable is less protected than cables installed in ducts. Therefore, internationally recognized requirements such as impact, alternated flexions, torsion, compression and bending tests should be adhered to. Specific tests or specific conditions for usual tests should be agreed upon by users and suppliers. Usually, mechanical protection can be achieved by adjusting the radial sheath thickness and/or the application of armouring which can be implemented as steel wire armour, galvanized steel tape armour or steel braid, or glass yarn/tape armour. + +## **6.4 Biotic damage** + +The size and deployment of an optical fibre cable can make it vulnerable to biological attacks. + +This topic is covered in [ITU-T L.161]. + +## **6.5 Electrical characteristics** + +#### **6.5.1 Lightning** + +Fibre cables containing metallic elements, such as metallic sheaths, strength members, hybrid cable conventional copper pairs or coaxial units are susceptible to lightning strikes. While less susceptible than directly buried cables, lightning fields in the ground surrounding metallic components or adjacent cables can arc to directly buried cables causing damage. + +To prevent or minimize lightning damage, consideration should be given to [ITU-T K.29] and [ITU-T K.47]. + +#### **6.5.2 Electrical continuity** + +If metallic elements are used in the cable, they should be electrically continuous. The resistivity of the metallic members should be checked if specified. The reference test method is [IEC 60794-1-403]. + +#### **6.5.3 Installation near high-voltage power line** + +If a fibre optic cable is buried directly adjacent to high-voltage power lines a special sheath material should be considered to avoid tracking effects. Depending on the conductivity of the soil, a voltage gradient may be generated by the electric field of the power line. Under the variation of conductivity, high-voltage difference may result on the jacket of the optical fibre cable and lead to leakage currents and dry-band arcing, which can damage the jacket over time. One solution, which is typical, is the use of a semiconductive over-jacket. The function of the semiconductive over-jacket is to reduce the high-voltage difference. Another solution is using a track-resistant jacket compound. + +# **7 Cable construction** + +## **7.1 Fibre coatings** + +#### **7.1.1 Primary coating** + +Silica fibre itself has an intrinsically high strength, but its strength is reduced by surface flaws. A protective primary coating is characteristically applied immediately after drawing the fibre to size. + +The optical fibre should be proof-tested. In order to guarantee long-term reliability under service conditions, the proof-test strain may be specified, taking into account the permissible strain and required lifetime. Agreed norms for fibre strain in testing and service are discussed in clause A.3.1. + +NOTE 1 – The optical fibres should be proof tested with a strain equivalent to 1 per cent or as agreed. For certain applications, a larger proof-test strain may be necessary. + +In order to prepare the fibre for splicing, it should be possible to remove the primary coating without damage to the fibre, and without the use of materials or methods considered to be hazardous or dangerous. + +The composition of the primary coating, coloured if required, should be considered in relation to any requirements of local light-injection and detection equipment used in conjunction with fibre jointing methods. + +NOTE 2 – Further study is required to advise on suitable testing methods for local light-injection and detection. + +Primary-coated fibres should comply with the relevant optical fibre specifications in [IEC 60793-2-50]. + +#### **7.1.2 Fibre buffer (secondary coating)** + +A secondary coating, termed a buffer, may be applied directly over the fibre primary coating for a variety of reasons. This is not to be confused with a buffer tube, which is discussed in clause 7.2.4. + +Buffers may use single or multiple materials. The buffer may be a tight buffer, intimately in contact with the primary coating, or a semi-tight buffer, in contact with the primary coating but intended for removal without damaging the primary coating. + +Both types of fibre buffer, if used, should comply with the requirements given in [IEC 60794-3]. + +NOTE – When a fibre buffer is used, it may be difficult to use local light-injection and detection equipment associated with fibre jointing methods. + +#### **7.1.3 Fibre identification** + +Fibre should be easily identified by colour/tracer/marker and/or position within the cable core. If a colouring method is used, the colours should be clearly distinguishable and have good colour permanence properties, also in the presence of other materials, during the lifetime of the cable. The need for fibre identification extends to the fibre units (ribbons, slots, buffer tubes, bundles, micro-bundles, etc.). Unit identification may include colours, printed marks, position in the core, or other appropriate means. + +Guidance may be found in [b-IEC TR 63194]. + +#### **7.1.4 Strippability of coating** + +The primary and secondary coatings should be easy to remove and should not hinder the splicing, or fitting of fibre to optical connectors. + +## **7.2 Cable elements** + +The make-up of the cable core – in particular the number of fibres, their method of protection and identification, the location of strength members and metallic wires or pairs, if required – should be clearly defined. + +#### 7.2.1 Fibre bundle + +Grouping of optical fibres into bundled units is a common method of organizing and identifying fibres within cable cores. Such bundles are commonly assembled using spirally-applied threads or tapes, often colour-coded, to assist in fibre identification. Other methods following this intent may be used. Such bundles may reside in slotted core (see clause 7.2.3), buffer tubes (see clause 7.2.4), micro-modules (see clause 7.2.5), or other core structures. + +#### 7.2.2 Fibre ribbon + +Optical fibre ribbons should conform to [IEC 60794-1-31]. + +Optical fibre ribbons consist of optical fibres aligned in a row. Optical fibre ribbons are designated by types, based on the method used to bind the fibres. Common types are the edge-bonded type, the encapsulated type, and the partially-bonded type. These are shown in Figures 1, 2, and 3, respectively. + +In the case of the edge-bonded type, optical fibres are bound by adhesive material located between the optical fibres. In the encapsulated type, optical fibres are bound by coating material covering the entire ribbon structure. In either of these basic types, the partially-bonded configuration may be used to accomplish additional flexibility in the transverse direction. This allows the ribbon to be rolled and accommodated in small core structures. + +The fibres of optical fibre ribbons in the as-manufactured configuration should be parallel and not cross. Optical fibre ribbons should be capable of mass splicing. Each ribbon in a cable should be identified by a printed legend or unique colour (see also clause 7.1.3). + +![Cross-section of a typical edge-bonded ribbon](7d066b8cdb123b3cba3584e8bb66f557_img.jpg) + +The diagram shows two possible cross-sectional views of an edge-bonded ribbon. Each view consists of four circular optical fibres arranged in a horizontal row. The fibres are connected at their top and bottom outer edges by a solid black line, representing the adhesive bonding. The word "or" is placed between the two diagrams. The label "L.101(24)" is located below the right-hand diagram. + +Cross-section of a typical edge-bonded ribbon + +Figure 1 – Cross-section of a typical edge-bonded ribbon + +![Cross-section of a typical encapsulated ribbon](601cbf7e7b6a7dd9a260c57031279e13_img.jpg) + +The diagram shows a cross-sectional view of an encapsulated ribbon. It consists of four circular optical fibres arranged in a horizontal row, all of which are completely surrounded by a single, solid black rectangular coating. The label "L.101(24)" is located below the diagram. + +Cross-section of a typical encapsulated ribbon + +Figure 2 – Cross-section of a typical encapsulated ribbon + +![Example of a typical partially bonded ribbon](cd1fc67b0180f1bff43410ac3b644c46_img.jpg) + +The diagram shows a perspective view of a partially bonded ribbon. It consists of four optical fibres arranged in a row. The top two fibres are connected to each other by a solid line, representing a bond. The bottom two fibres are also connected to each other by a solid line. The top fibre is connected to the third fibre (counting from the top) by a dashed line, representing a bond. The third fibre is connected to the fourth fibre by a dashed line. The label "Not bonded" has arrows pointing to the gaps between the top and third fibres, and between the third and fourth fibres. The label "Bonded" has arrows pointing to the solid lines connecting the top two fibres and the bottom two fibres. The label "L.101(24)" is located below the diagram. + +Example of a typical partially bonded ribbon + +Figure 3 – Example of a typical partially bonded ribbon + +#### 7.2.3 Slotted core + +In order to avoid direct pressure from the outside of the cable on optical fibres, optical fibres and/or fibre ribbons or other units may be located in slots inside a core structure. Figure 4 shows an example of a slotted core structure cable. Usually, slots are provided in a helical or reverse oscillating stranding + +(SZ) method configuration on a cylindrical rod. The slotted core rod usually contains a strength member (metallic or non-metallic). The strength member should adhere tightly to the slotted core in order to obtain temperature stability and avoid separation when a pulling force is applied during installation. Water-blocking material may be contained within the slots. + +![Figure 4: Example of a slotted core structure cable. The diagram shows a cross-section of a cable. At the center is a circular 'Strength member (Tension member)'. Surrounding it is a 'Slotted core' with 11 numbered slots (1 through 11). Each slot contains a 'Ribbon', depicted as a rectangle with horizontal lines. The entire assembly is enclosed in a 'Sheath'. Lines point from labels to these components. The label 'L.101(24)' is at the bottom.](b0d9faaee53565a4a333764297aa7b97_img.jpg) + +Figure 4: Example of a slotted core structure cable. The diagram shows a cross-section of a cable. At the center is a circular 'Strength member (Tension member)'. Surrounding it is a 'Slotted core' with 11 numbered slots (1 through 11). Each slot contains a 'Ribbon', depicted as a rectangle with horizontal lines. The entire assembly is enclosed in a 'Sheath'. Lines point from labels to these components. The label 'L.101(24)' is at the bottom. + +**Figure 4 – Example of a slotted core structure cable** + +#### **7.2.4 Tube (buffer tube)** + +A tube construction, commonly called a buffer tube or loose tube, is frequently used for protecting and gathering optical fibres, fibre bundles, and/or fibre ribbons. Figure 5 shows an example of a loose tube cable construction. The essential feature of the tube is sufficient space inside the tube to isolate fibres, fibre bundles, or ribbons from external stress. The tubes are commonly made of polymer materials. Cable designs incorporating loose tubes are the most widely deployed, offering an optimized package for handling and robustness. The tubes may be stranded around the other tubes or the central strength member. Such core structures minimize strain and mid-span access may be easier if the SZ method is utilized. Central tube designs may also be used. Water-blocking material may be contained in the tube, if required. + +NOTE – A particularly rugged cable design may utilize a metal tube construction with a welded seam instead of polymer tube, see Appendix I of [b-ITU-T L.110]. + +![Figure 5: Example of a loose tube cable construction. The diagram shows a cross-section of a cable. At the center is a 'Central strength member'. Surrounding it are six circular 'Buffer tube' units, each containing several small colored circles representing 'Fibre'. 'Water blocking material' is indicated inside the tubes. A yellow ring labeled 'Water blocking/ binding tape/ strength member' surrounds the tubes. A 'Ripcord' is shown as a small black dot. The outermost layer is the 'Outer sheath (Jacket)'. The label 'L.101(24)' is at the bottom.](5fcce2e86d32d2c79f94c7bbd6601358_img.jpg) + +Figure 5: Example of a loose tube cable construction. The diagram shows a cross-section of a cable. At the center is a 'Central strength member'. Surrounding it are six circular 'Buffer tube' units, each containing several small colored circles representing 'Fibre'. 'Water blocking material' is indicated inside the tubes. A yellow ring labeled 'Water blocking/ binding tape/ strength member' surrounds the tubes. A 'Ripcord' is shown as a small black dot. The outermost layer is the 'Outer sheath (Jacket)'. The label 'L.101(24)' is at the bottom. + +**Figure 5 – Example of a loose tube cable construction** + +#### **7.2.5 Micro-module** + +A micro-module is a thin-walled tubing unit (typically smaller and less robust than the buffer tube described in clause 7.2.4). These flexible modules have bending radii similar to the unbundled fibre or fibre bundles and are easy to strip without a tool for easy splice preparation and mid-span access. They have no shape memory and may be used directly in an enclosure up to the splicing tray. Water- + +blocking material may be contained within the micro-module, if required. Micro-modules may be used within buffer tubes or slots. A typical micro-module is shown in Figure 6. + +![Figure 6: Cross-section of a micro-module containing multiple primary coated fibres.](33e70787e71eebc7a200bc7fe352dadc_img.jpg) + +A cross-sectional diagram of a micro-module. It consists of an outer teal-colored ring labeled 'Thin and low modules wall tubing'. Inside this ring, there are ten small green circles representing 'Fibre' units, arranged in a circular pattern. The space between these fibres is filled with a 'Filling compound or dry filling solution'. A label 'L.101(24)' is located at the bottom right of the diagram. + +Figure 6: Cross-section of a micro-module containing multiple primary coated fibres. + +**Figure 6 – Example of primary coated fibres protected by micro-module** + +#### 7.2.6 Ruggedized fibre + +When required for particular applications, further protection for a buffered fibre (see clause 7.1.2) may be provided by surrounding one or more such fibres with an assembly of strength elements, typically non-metallic, and an appropriate jacket material. Such assemblies are small in size and typically reside in the cable core. Such ruggedization may be appropriate for break-out/fan-out cable constructions. Figure 7 shows examples of ruggedized fibre structure. + +![Figure 7: Two examples of ruggedized fibre structure.](6c87dea9e65426eedb6b2a6838b12274_img.jpg) + +Two cross-sectional diagrams of ruggedized fibre structures. The left diagram shows a single fibre assembly consisting of a central green 'Buffered fibre', surrounded by a white 'Aramid yarn' layer, and an outer blue 'Sheath'. The right diagram shows a dual-fibre assembly where two such individual fibre assemblies (each with a green 'Buffered fibre', white 'Aramid yarn', and blue 'Sheath') are joined together at their sheaths. A label 'L.101(24)' is located at the bottom right of the right-hand diagram. + +Figure 7: Two examples of ruggedized fibre structure. + +**Figure 7 – Examples of ruggedized fibre structure** + +#### 7.2.7 Strength member + +The directly buried cable should be designed with sufficient strength members to meet installation and service conditions so that the fibres themselves are not subjected to strain levels in excess of the standard values (see clause A.3.1) or as agreed upon between customer and manufacturer. + +Strength members mainly serve to limit tensile strain, but may also serve to limit compressive strain as in temperature changes. The strength members may be located within the core or in the sheath layers, or both. The strength member(s) may be either metallic or non-metallic. + +When metallic strength members are used, they should be electrically continuous (see clause 6.5.2) and care should be taken to avoid hydrogen generation effects (see clause 6.3.8) and lightning hazards (see clause 6.5.1). + +#### 7.2.8 Water-blocking materials + +Most directly buried cables are water-blocked to protect the fibres from water ingress (see clause 6.3.3 regarding air-core cables). Filling a cable – core and sheath interstices – with water-blocking material or wrapping these areas with layers of water-swellable material, or both, are common methods to protect the fibres from water ingress. A water-blocking element – filling compounds, water-swellable yarns or tapes, water-swelling powder, or combinations of materials – + +may be used. Any materials used should not be harmful to personnel. The materials in the cable should be compatible with one another, and in particular should not adversely affect the fibre. These materials should not hinder splicing and/or connection operations (see clause A.4.7). + +## **7.3 Sheath and jacket** + +### **7.3.1 General** + +The cable sheath is the assembly of elements that cover the cable core. This term may also be used to mean the part of the assembly, which is the main covering of the cable, often termed the jacket. The cable core should be covered with a sheath or sheaths suitable for the relevant environmental and mechanical conditions associated with storage, installation, and operation. The sheath may be of a composite construction and may include strength members. The sheath may include a moisture barrier or inner jacket or armour, as needed, in addition to an outer jacket. The materials of the sheath should be compatible with all of the elements of the cable sheath and core. + +#### **7.3.2 Moisture barrier** + +A moisture barrier may be one element of a cable sheath to inhibit moisture permeation (see clause 6.3.4). If used, consideration should be given to the amount of hydrogen generated from a metallic moisture barrier (see clause 6.3.8). + +#### **7.3.3 Inner sheath (jacket)** + +An inner sheath (jacket) layer may be used in the cable construction. The inner sheath may provide additional protection under an armour, may be used to organize a cable as in break-out/fan-out cables, or for other reasons. + +#### **7.3.4 Outer sheath (jacket)** + +The outer sheath (jacket) is the final covering of the cable. The selection of the outer sheath material should be selected to resist the expected environmental hazards. + +NOTE – One of the most commonly used sheath materials is polyethylene. There may, however, be some conditions where it is necessary to use other materials, for example, to limit fire hazards; to protect from rodents and/or termites, etc. + +## **7.4 Armour** + +Where protection from external damage (e.g., crush, impact, rodents) or additional tensile strength is required armour should be provided. + +Common metallic armour materials are steel tapes of various constructions. The armour should also provide the sufficient radial as well as compressive strength and the metallic armour should be electrically continuous (see clause 6.5.2) and bonded to the outer sheath if armouring acts as a moisture barrier. Other metallic materials are occasionally used. Hydrogen generation due to corrosion must be taken into consideration (see clause 6.3.8). + +Armour for metal-free cables may consist of aramid yarns, glass-fibre -reinforced strands, strapping tape, etc. + +It should be noted that the advantages of optical fibre cables, such as lightness and flexibility, will be reduced when armour is provided. + +## **7.5 Identification of cable** + +It is recommended that a visual identification of optical fibre cables be provided: this can be done by visibly marking the outer sheath. Marking of cable length should be included in cable marking. For identifying and length-marking cables, embossing, sintering, imprinting, hot foil, or ink-jet or laser printing can be used by agreement between manufacturer and customer. + +## **7.6 Cable sealing** + +It is recommended that an optical fibre cable should be provided with cable end-sealing and protection during cable delivery and storage. If splicing components have been factory installed, they should be adequately protected. Pulling devices can be fitted to the end of the cable, if required. + +# Annex A + +## Test methods + +(This annex forms an integral part of this Recommendation.) + +The tests are according to [IEC 60794-3-11] and the clauses below should be carried out for directly buried cables. The attribute values stated herein should be used to assess conformance in the tests. It is not intended that all tests should be carried out; see [IEC 60794-3-11] for guidance. See [IEC 60794-3] regarding the frequency of testing; this should be agreed upon between the manufacturer and customer. + +The test methods, performance and test criteria are summarized in Tables A.1 to A.7. + +**Table A.1 – Optical fibre and cable elements test conditions** + +| Characteristic | Clause | Test 1 | Value 1, 2, 3 | Note | +|----------------------------|--------|-------------------|--------------------------------------------------|------------------------| +| Attenuation coefficient | A.1.3 | [IEC 60793-1-40] | See Note 4 | | +| No changes in attenuation | A.1.3 | – | As specified in Note 5 | as per [IEC 60794-1-1] | +| No changes in fibre strain | A.1.3 | as applicable | As specified in Note 5 | as per [IEC 60794-1-1] | +| Ambient temperatures | A.1.4 | as applicable | Standard ambient and expanded ambient, see A.1.4 | as per [IEC 60794-1-2] | +| Other temperatures | A.1.5 | as applicable | within $\pm 5$ °C of the specified value | | + +NOTE 1 – Tests are IEC unless otherwise specified. Letter/number tests are per the [IEC 60794-1-2] series unless otherwise specified. +NOTE 2 – "as agreed" means per agreement between the manufacturer and the customer. +NOTE 3 – Reference to the L.101 invoking clause implies criteria not detailed in [IEC 60794-3-11] or the test method and overly complex for this table. +NOTE 4 – Cabled fibre attenuation coefficient is specified in corresponding ITU-T G.65x series Recommendation. +NOTE 5 – No changes in attenuation/strain are related to test uncertainty as per [IEC 60794-1-1]. + +**Table A.2 – Optical fibre and cable elements characteristics** + +| Characteristic | Clause | Test 1 | Value 1, 2, 3 | Note | +|-----------------------------|---------|-------------------------------------|--------------------------|----------------------| +| Fibre dimensions | A.2.1.1 | [IEC 60793-1-21] | per [IEC 60793-2-50] | per [IEC 60793-2-50] | +| Fibre coating strippability | A.2.1.2 | [IEC 60793-1-32] | per [IEC 60794-3-11] | | +| Material compatibility | A.2.1.3 | [IEC 60794-1-219] | [IEC 60794-1-219] | | +| Fibre buffers dimensions | A.2.3.1 | [IEC 60793-1-21] or [IEC 60811-203] | per [IEC 60794-3] or DS | | +| Buffer strippability | A.2.3.2 | E5C of [IEC 60794-1-21] | see A.2.3.2 | | +| Buffer tube dimensions | A.2.4.1 | [IEC 60811-202] and [IEC 60811-203] | per DS or as agreed | | +| Tube kink | A.2.4.2 | G7 of [IEC 60794-1-23] | per [IEC 60794-3-11] | | +| Fibre ribbons | | | | | + +**Table A.2 – Optical fibre and cable elements characteristics** + +| Characteristic | Clause | Test 1 | Value 1, 2, 3 | Note | +|----------------------|---------|---------------------------------------------|-----------------------------|------| +| Ribbon dimensions | A.2.5.1 | [IEC 60794-1-31] | Table 1 of [IEC 60794-1-31] | | +| Fibre separability | A.2.5.2 | [IEC 60794-1-31] | [IEC 60794-1-31] | | +| Ribbon strippability | A.2.5.3 | [IEC 60794-1-31]
and
[IEC 60793-1-32] | [IEC 60794-1-310] | | + +NOTE 1 – Tests are IEC unless otherwise specified. Letter/number tests are per the [IEC 60794-1-2] series unless otherwise specified. +NOTE 2 – "as agreed" means per agreement between the manufacturer and the customer. +NOTE 3 – Reference to the L.101 invoking clause implies criteria not detailed in [IEC 60794-3-11] or the test method and overly complex for this table. + +**Table A.3 – Mechanical characteristics** + +| Characteristic | Clause | Test 1 | Value 1, 2, 3 | Note | +|-------------------------|--------|---------------------------------------|------------------------------------------------------------------------|----------------------------------| +| Tensile strength | A.3.1 | E1 of [IEC 60794-1-21] | L M per 6.2.2 | per [IEC 60794-3-11] | +| Bending | A.3.2 | E11 of [IEC 60794-1-21] | per [IEC 60794-3-11] | E11A or E11B of [IEC 60794-1-21] | +| Bending under tension | A.3.3 | E18A, Procedure 2 of [IEC 60794-1-21] | per [IEC 60794-3-11] | | +| Repeated bending (flex) | A.3.4 | E6 of [IEC 60794-1-21] | per [IEC 60794-3-11]
No change in attenuation after the test | | +| Crush | A.3.5 | E3A of [IEC 60794-1-21] | per [IEC 60794-3-11]
see A.3.5 | plate/plate crush | +| Impact | A.3.6 | E4 of [IEC 60794-1-21] | per [IEC 60794-3-11]
see A.3.6 | | +| Torsion | A.3.7 | E7 of [IEC 60794-1-21] | per [IEC 60794-3-11]
see A.3.7 | | +| Abrasion, cable print | A.3.8 | E2A, Method 2 of [IEC 60794-1-21] | per [IEC 60794-3-11] | jacket abrasion not tested | +| Cable kink | A.3.9 | E10 of [IEC 60794-1-21] | 1 sample, ambient temperature, no kink, $d > \text{minimum}$ per 6.2.3 | not in [IEC 60794-3-11] | +| Vibration | A.3.10 | – | see A.3.10 | not usually required | + +NOTE 1 – Tests are IEC unless otherwise specified. Letter/number tests are per the [IEC 60794-1-2] series unless otherwise specified. +NOTE 2 – "as agreed" means per agreement between the manufacturer and the customer. +NOTE 3 – Reference to the L.101 invoking clause implies criteria not detailed in [IEC 60794-3-11] or the test method and overly complex for this table. + +**Table A.4 – Environmental characteristics** + +| Characteristic | Clause | Test 1 | Value 1, 2, 3 | Note | +|-------------------------------------------------------------------------------------------|-----------------------------|---------------------------------------------------|------------------------------------------------|--------------------------------------------------| +| Temperature cycling | A.4.1 | F1 of [IEC 60794-1-22] | see clause 6.3.2 | | +| Ageing | A.4.2 | F9 of [IEC 60794-1-22] | as agreed | may be extension of F1 of [IEC 60794-1-2] | +| Water penetration | A.4.3 | F5B or F5C of [IEC 60794-1-22], as applicable | per [IEC 60794-3-11]
no leakage after 24 hr | | +| Moisture penetration | A.4.4 | [IEC 60708] | as agreed | not commonly tested | +| Pneumatic resistance | A.4.5 | F8 of [IEC 60794-1-22] | as agreed | | +| Freezing | A.4.6 | Method A or B of [IEC 60794-1-215], as applicable | as agreed | applicability dependent on deployment conditions | +| Material compatibility
– Jacket tensile, aged
– Metal coatings delamination testing | A.4.7
A.4.7.2
A.4.7.3 | [IEC 60794-1-219] | ≥ 75% of unaged no delamination | | +| OIT | A.4.8 | [ISO 11357-6] and per A.4.8 | OIT ≥ 20 min. | | +| Hydrogen | A.4.9 | – | see [ITU-T L.126] and [b-IEC TR 62690] | not usually required | +| Nuclear radiation | A.4.10 | F7 of [IEC 60794-1-22] | see A.4.10 | not usually required | +| Cable sheath adherence | A.4.11 | [IEC 61196-1-313] | see A.4.11 | for flooded-armour constructions | + +NOTE 1 – Tests are IEC unless otherwise specified. Letter/number tests are per the [IEC 60794-1-2] series unless otherwise specified. +NOTE 2 – "as agreed" means per agreement between the manufacturer and the customer. +NOTE 3 – Reference to the L.101 invoking clause implies criteria not detailed in [IEC 60794-3-11] or the test method and overly complex for this table. + +**Table A.5 – Biotic characteristics** + +| Characteristic | Clause | Test 1 | Value 1, 2, 3 | Note | +|--------------------------------------------------|--------------------|--------------------|----------------------------------------------|------| +| Biotic damage
– Rodent and insect
– Fungus | A.5.1.1
A.5.1.2 | –
[ITU-T L.161] | as agreed, see 6.4
as agreed, see A.5.1.2 | | + +NOTE 1 – Tests are IEC unless otherwise specified. Letter/number tests are per the [IEC 60794-1-2] series unless otherwise specified. +NOTE 2 – "as agreed" means per agreement between the manufacturer and the customer. +NOTE 3 – Reference to the L.101 invoking clause implies criteria not detailed in [IEC 60794-3-11] or the test method and overly complex for this table. + +**Table A.6 – Electrical characteristics** + +| Characteristic | Clause | Test 1 | Value 1, 2, 3 | Note | +|-----------------------|--------|-------------------|--------------------------|----------------------------------| +| Lightning | A.6.1 | [ITU-T K.47] | see clause 6.5.1 | not usually required | +| Electrical continuity | A.6.2 | [IEC 60794-1-403] | as agreed, see A.6.2 | For cable with metallic elements | + +NOTE 1 – Tests are IEC unless otherwise specified. Letter/number tests are per the [IEC 60794-1-2] series unless otherwise specified. +NOTE 2 – "as agreed" means per agreement between the manufacturer and the customer. +NOTE 3 – Reference to the L.101 invoking clause implies criteria not detailed in [IEC 60794-3-11] or the test method and overly complex for this table. + +**Table A.7 – Cable construction** + +| Characteristic | Clause | Test 1 | Value 1, 2, 3 | Note | +|---------------------------|---------|-------------------------------------|----------------------------------------------|------| +| Dimensions | A.2.6.1 | [IEC 60811-202] and [IEC 60811-203] | as agreed | | +| Cable OD | A.2.6.2 | [IEC 60811-203] | stated by manufacturer, per [IEC 60794-3-11] | | +| Sheath thickness | A.2.6.3 | [IEC 60811-203] | per [IEC 60794-3-11] or as agreed | | +| Moisture barrier adhesion | A.2.6.4 | [IEC 60708] | per [IEC 60794-3-11] | | + +NOTE 1 – Tests are IEC unless otherwise specified. Letter/number tests are per the [IEC 60794-1-2] series unless otherwise specified. +NOTE 2 – "as agreed" means per agreement between the manufacturer and the customer. +NOTE 3 – Reference to the L.101 invoking clause implies criteria not detailed in [IEC 60794-3-11] or the test method and overly complex for this table. + +## A.1 Standard test criteria + +#### A.1.1 Tensile strength of directly buried cables + +Testing for criteria involving cable tensile strength should be carried out using the tensile rating of clause 6.2.2. + +#### A.1.2 Temperature test values for directly buried cables + +Testing for criteria involving defined temperature extremes should be considered to be carried out using the temperature ranges. Some tests may specify specific test temperatures different from the standard temperature ranges. + +#### A.1.3 Attenuation coefficient and changes (no change and allowable change) in attenuation/strain in cable testing + +Unless otherwise specified, testing for attenuation requirements should be carried out at 1550 nm for all single-mode fibres. + +Unless otherwise specified, changes in attenuation should be calculated with respect to the attenuation values before the start of the test. In most cases, this measurement should be at ambient temperature (see clause A.1.4). + +Unless otherwise specified, for tests with attenuation requirements the attenuation increase or decrease at the completion of the test should be no change. + +Unless otherwise specified, the defined values for "no change" should be per [IEC 60794-1-1], which are: + +- single-mode, attenuation change $\leq 0.05$ dB at 1 550 nm +- single-mode, attenuation coefficient change $\leq 0.05$ dB/km at 1 550 nm +- all types, no change in fibre strain $\leq 0.05\%$ + +#### A.1.4 Ambient temperatures for cable testing + +The ambient temperatures for cable testing should be according to [IEC 60794-1-2] as shown in Table A.8. All testing should use the expanded ambient criteria unless disallowed by the test procedure or as agreed. + +**Table A.8 – Ambient temperature, relative humidity, and atmospheric pressure** + +| Condition | Standard ambient | Expanded ambient | +|----------------------|------------------|-------------------| +| Temperature | 23 °C $\pm$ 5 °C | 25 °C $\pm$ 15 °C | +| Relative humidity | 20% to 70% | 5% to 95% | +| Atmospheric pressure | Site ambient | Site ambient | + +#### A.1.5 Temperature precision at extremes + +The temperature value at test temperatures other than ambient should be within $\pm 5$ °C of the specified values (see clause 6.3.2 and clause A.1.4). + +### A.2 Test methods for cable elements + +#### A.2.1 Tests applicable to optical fibres + +In this clause, optical fibre test methods for assessing fibres and test methods related to splicing and other joining methods are described. Mechanical and optical characteristics test methods for optical fibres are described in [ITU-T G.650.1], [ITU-T G.650.2] and [IEC 60793-1-xx] fibre test methods series. + +##### A.2.1.1 Dimensions + +For measuring the primary coating diameter, method [IEC 60793-1-21] should be used. + +The measured dimensions for cabled fibre should be per [IEC 60793-2-50] or as agreed. + +##### A.2.1.2 Coating strippability + +For measuring the strippability of primary or secondary fibre coatings, method [IEC 60793-1-32] should be used. The strip force should be according to [IEC 60794-3-11]. + +##### A.2.1.3 Compatibility with filling materials + +When fibres come into contact with a filling material used for waterproofing, stability of the fibre coating and the filling material should be examined by tests after accelerated ageing. + +Compatibility of optical fibres and buffers with a filling material should be tested per [IEC 60794-3-11]. + +Dimensional stability and coating transmissivity should be examined by the test method as agreed. + +#### A.2.2 Tests applicable to fibre units + +##### A.2.2.1 Colour coding of fibre + +There is no international standard on fibre colour coding. The fibre colouring should comply with the detailed specification (DS), which may reflect in National or Regional norms. See [b-IEC TR 63194] for guidance. + +Colours used should comply with [IEC 60304]. + +##### A.2.2.2 Fibre and unit identification + +Fibre and unit identification should also comply with the DS, which may be reflected in National or Regional norms. See [b-IEC TR 63194] for guidance. + +Colours used should comply with [IEC 60304]. + +#### A.2.3 Tests applicable to buffered optical fibres + +##### A.2.3.1 Dimensions + +The outer diameter of all types of fibre secondary coatings (buffers) should comply with [IEC 60794-3] or with the DS. The diameter tolerance should comply with [IEC 60794-3]. + +Measurements should be performed using [IEC 60793-1-21] or [IEC 60811-203]. + +##### A.2.3.2 Buffer strippability + +Buffers should be strippable in a manner consistent with their intended method of connectorisation or splicing. + +Buffers should be capable of being stripped using the parameters as shown in Table A.9. Stripping methods and measurements should be performed according to [IEC 60794-1-21] method E5C. + +**Table A.9 – Strip lengths and forces for buffer strippability test** + +| Buffer type | Material stripped | Strip length | Strip force | +|-----------------------------|---------------------------------------------|--------------------|---------------| +| Tight | Remove buffer and primary coating as a unit | 15 mm $\pm$ 1.5 mm | 1.3 N to 13 N | +| Semi-tight | Remove buffer, primary coating intact | 15 mm $\pm$ 1.5 mm | < 13 N | +| Easily-removable semi-tight | Remove buffer, primary coating intact | 150 mm | as agreed | + +#### A.2.4 Tests applicable to buffer tubes + +##### A.2.4.1 Dimensions + +Buffer tube dimensions should be according to the DS or as agreed between manufacturer and customer. + +For measuring buffer tubes the methods of [IEC 60811-202] and [IEC 60811-203] should be used. + +##### A.2.4.2 Tube kink + +Tube kinking characteristics and testing should be according to [IEC 60794-3-11]. + +For measuring kink characteristics of tubes, [IEC 60794-1-23] method G7 should be used. + +#### **A.2.5 Tests applicable to ribbons** + +##### **A.2.5.1 Dimensions** + +Fibre ribbon dimensions should be according to [IEC 60794-1-31], Table 1. Ribbon dimensions should be measured according to [IEC 60794-1-31]. + +##### **A.2.5.2 Separability of individual fibres from a ribbon** + +Separability of individual fibres from a ribbon should be according to [IEC 60794-1-31]. + +##### **A.2.5.3 Ribbon strippability** + +Strippability of ribbons, as a whole or in units, should be according to [IEC 60794-1-31] and as follows. + +At least 25 mm of the matrix and the fibres' protective coatings should be removable with commercially available stripping tools from aged and unaged ribbons. There should be no fibre breakage. Any remaining coating residue should be readily removable using isopropyl alcohol wipes. Ribbon ageing is under study. Stripping force should be measured using [IEC 60793-1-32] as applicable to the multiple fibres in a ribbon. + +#### **A.2.6 Cable element measurements** + +##### **A.2.6.1 Dimensions** + +Dimensions for other tubes, slotted core, micro-modules, other ruggedized fibres, strength members, jackets, or other cable elements should be as agreed between the manufacturer and customer. + +Measurement of these cable elements should use methods provided in [IEC 60811-202] and [IEC 60811-203], as applicable. + +##### **A.2.6.2 Cable diameter** + +The cable outer diameter should not exceed the maximum stated by the manufacturer in accordance with [IEC 60794-3-11]. + +The measurement should be in accordance with [IEC 60811-203]. + +##### **A.2.6.3 Sheath thickness** + +The sheath thickness of directly buried cable should be in accordance with [IEC 60794-3-11], or as alternately agreed between the manufacturer and customer. + +Measurement should be in accordance with [IEC 60811-203]. + +##### **A.2.6.4 Moisture barrier adhesion** + +If a moisture barrier tape is used, it should be in accordance with [IEC 60794-3-11]. + +The adhesion of the tape to the sheath should be tested in accordance with [IEC 60708]. + +### **A.3 Test methods for mechanical characteristics of the cable** + +This clause recommends appropriate tests and test methods for verifying the mechanical characteristics of directly buried cables. + +Performance and acceptance criteria and testing should comply with [IEC 60794-3] and [IEC 60794-3-11] and the clauses below. Testing should be done according to [IEC 60794-1-21] and its subordinate specifications. + +In many cases, visual examination of a directly buried cable during or after testing is appropriate. + +Visual examination of cables should be done using normal or normal corrected vision. Examination using magnification is needed. This provides the most effective combination of enlargement and depth-of-field. + +#### **A.3.1 Tensile strength** + +This test method applies to directly buried cables installed under all environmental conditions. Measurements are made to examine the behaviour of the fibre attenuation and fibre strain as a function of the load on a cable during installation and during its lifetime. + +The cable should perform in accordance with [IEC 60794-3-11], using the criteria below. + +The rated tensile load, also termed short-term load, $L_S$ , should be the nominal value consistent with the tensile load ratings of clause 6.2.2. The residual load, or long-term load, $L_L$ , should be 30% of $L_S$ , as per clause 6.2.2. + +A tensile rating in excess of $L_S$ may be declared by the manufacturer. But, testing should be carried out at the rated tensile load. + +The maximum changes in attenuation should be: + +- Attenuation changes should not be specified at $L_S$ , as this is a short-term load event. +- There should be no change in attenuation at $L_L$ and after removal of the load; see clause A.1.3. + +The fibre strain under load should be: + +- $\leq 60\%$ of the fibre proof strain under load $L_S$ ; +- $\leq 20\%$ of the fibre proof strain under load $L_L$ , for fibres proof tested at 1% strain; or $\leq 17\%$ of the fibre proof strain under load $L_L$ , for fibres proof tested at greater than 1% up to 2% strain. + +The test should be carried out in accordance with [IEC 60794-1-21] method E1. + +There should be no damage to the sheath or cable elements under visual examination. + +#### **A.3.2 Bending** + +This test method applies to directly buried cables installed under all environmental conditions. + +The purpose of this test is to determine the ability of optical fibre cables to withstand coiling or bending around a pulley, simulated by a test mandrel. + +The cable should perform in accordance with [IEC 60794-3-11]. + +This test should be carried out in accordance with [IEC 60794-1-21] method E11. The bending diameter should be according to clause 6.2.3. The mandrel or sheave diameter should be $\pm 10\%$ of the specified value. + +#### **A.3.3 Bending under tension** + +This test method applies to directly buried cables installed under all environmental conditions. + +The purpose of this test is to determine the ability of an optical fibre cable to withstand bending around rollers or bows during installation, when a specified load is applied. + +This test should be carried out in accordance with [IEC 60794-1-21] method E18A, procedure 2: + +- tension: cable rated tensile load, $L_S$ ; +- length of cable tested in the bend: distance required for the circuit between the roller/sheave exits, plus 10 m; + +- length of cable/end preparation: + no end preparation required for cable length of 100 m or greater + cable elements fixed together at either end for cable lengths less than 100 m; +- radius of rollers/sheaves, R: + $1/2 \times (20 \times d \text{ or } 40 \times d, \text{ per clause 6.2.3}), \pm 10\%$ ; +- bending angle, $\theta$ : between $90^\circ$ and $135^\circ$ ; +- number of cycles: 3. + +There should be no change in attenuation after the test. + +There should be no visible cracking of the sheath components when removed successively and examined. + +#### A.3.4 Repeated bending + +This test method applies to directly buried cables installed under all environmental conditions. + +The purpose of this test is to evaluate the ability of optical fibre cables to undergo repeated bending associated with normal handling and service. + +The cable should perform in accordance with [IEC 60794-3-11], and tested in accordance with [IEC 60794-1-21] method E6 with the following criteria: + +- mandrel radius, r: $1/2 \times 20 d$ (per clause 6.2.3), with a minimum value of 150 mm, $\pm 10\%$ . + +The maximum increase in attenuation during the test should be: + +- $\leq 0.15$ dB at 1 550 nm for single-mode fibres. + +There should be no change in attenuation after the test. + +There should be no visible cracking of any armour or shield greater than 5 mm in length. Inspection should be performed using $5 \times$ magnification. There should be no visible damage to the other cable elements. + +#### A.3.5 Crush + +This test method applies to directly buried cables installed under all environmental conditions. + +The appropriate test method for most terrestrial cables is the plate-plate crush method. + +The cable should perform in accordance with [IEC 60794-3-11], and tested in accordance with [IEC 60794-1-21] method E3A using the following criteria: + +- Short-term test segment – load applied for 1 min. +- Long-term test segment – load applied for 10 min. +- Plate/plate loads, per [IEC 60794-3-11] as shown in Table A.10. +- Measure attenuation at the end of the long-term loading, before releasing the load. + +There should be no change in attenuation at the end of the long-term loading. + +**Table A.10 – Plate/plate loads for crush test** + +| | Short-term | Long-term | +|------------------|------------|-----------| +| Unarmoured cable | 1.5 kN | 0.75 kN | +| Armoured cable | 2.2 kN | 1.1 kN | + +#### **A.3.6 Impact** + +This test method applies to directly buried cables installed under all environmental conditions. + +The purpose of this test is to evaluate the ability of optical fibre cables to survive impacts associated with normal installation and handling. + +The cable should perform in accordance with [IEC 60794-3-11], and tested in accordance with [IEC 60794-1-21] method E4 using the following criteria: + +- Use the standard, flat hammer (300 mm minimum face radius). +- Strike the cable 1 time in each of 3 different places, spaced not less than 150 mm $\pm$ 15 mm apart. +- Use an impact energy of: +10 J for non-armoured cable; +20 J for armoured cable. + +#### **A.3.7 Torsion** + +This test method applies to directly buried cables installed under all environmental conditions. + +The purpose of this test is to evaluate the ability of optical fibre cables to accommodate torsion associated with normal installation and handling. + +The cable should perform in accordance with [IEC 60794-3-11], and tested in accordance with [IEC 60794-1-21] method E7 using the following criteria: + +- Length under test: 2 m. +- Sample rotation: 180° in each direction. +- 5 cycles. + +NOTE – Different sample lengths and rotations equivalent to 90°/m may be used. + +After the test, there should be no change in attenuation. + +#### **A.3.8 Abrasion of cable printing** + +This test method applies to directly buried cables installed under all environmental conditions. + +The purpose of this test is to evaluate the permanence of cable printing. + +The cable should perform in accordance with [IEC 60794-3-11], and tested in accordance with [IEC 60794-1-21] method E2A, Method 2. This method tests the print using the felt pad method. + +After the test, the cable printing should still be legible. + +#### **A.3.9 Kink** + +This test method applies to directly buried cables installed under all environmental conditions. + +The purpose of this test is to evaluate the ability of optical fibre cables to undergo normal handling without kinking. + +This test should be carried out in accordance with [IEC 60794-1-21] method E10. The test criteria should be: + +- Test 1 sample. +- Perform the test at ambient temperature. + +The cable should not kink at a loop diameter greater than the cable minimum bend diameter (see clause 6.2.3). There should be no attenuation requirement. + +#### **A.3.10 Vibration** + +Vibration testing should be as agreed between the manufacturer and customer (see clause 6.2.7). + +### **A.4 Test methods for environmental characteristics** + +This clause recommends the appropriate tests and test methods for verifying the environmental characteristics of directly buried cables. + +Performance and acceptance criteria and testing should comply with [IEC 60794-3] and [IEC 60794-3-11] and the clauses below. Testing should be done according to [IEC 60794-1-2] and its subordinate specifications. + +Appropriate temperature ranges for directly buried cables are shown in clause 6.3.2, Table 1. Unless other temperature ranges are specified for particular applications, the values in Table 1 should be used. + +#### **A.4.1 Temperature cycling** + +This test method applies to directly buried cables installed under all environmental conditions. + +Testing is carried out by temperature cycling to determine the stability of the attenuation of a cable due to temperature changes, which may occur during operation. + +The cable should perform in accordance with [IEC 60794-3-11], and tested in accordance with [IEC 60794-1-22] method F1 at the operational temperature per clause 6.3.2, Table 1. These temperatures are TA2 and TB2 of method F1. Other temperature values or intermediate values in method F1 should be as agreed between manufacturer and customer. + +Attenuation changes at all temperatures should be calculated as deviations from the value at the initial measurement at ambient temperature. + +There should be no change in attenuation at ambient temperature after the test. + +#### **A.4.2 Ageing** + +This test method applies to directly buried cables installed under all environmental conditions. + +The purpose of this test is to evaluate the reaction of cable components under simulated ageing by applying a high temperature to accelerate ageing. + +This test should be carried out in accordance with [IEC 60794-1-22] method F9, usually as an extension of the temperature cycling test of clause A.4.1. + +Attenuation changes at the end of the ageing period should be calculated as deviations from the value at initial ambient for this test. If this test is carried out as an extension of the temperature cycling test, the initial ambient point for ageing is at the end of the temperature cycling test. Unless otherwise specified, the attenuation change at the end of the test should be: + +- 0.25 dB/km, maximum, and 0.10 dB/km, average, at 1 550 nm for single-mode fibres. + +#### **A.4.3 Longitudinal water penetration** + +This test method applies to water-blocked outdoor cables installed under all environmental conditions. + +The intention is to check that all the interstices of a cable are sufficiently filled with a compound or water blocking material to prevent water penetration within the cable. + +The cable should perform in accordance with [IEC 60794-3-11]. Testing should be carried out in accordance with [IEC 60794-1-22] method F5B or [IEC 60794-1-22] method F5C, as appropriate to the design. + +There should be no leakage at the end of the cable after 24 hours in the test or retest, as per [IEC 60794-1-22] method F5. + +#### **A.4.4 Moisture permeation** + +This test method applies to directly buried cables installed under all environmental conditions. + +This test applies to cables supplied with a longitudinal overlapped metallic foil. The moisture permeation can be tested according to the test method [IEC 60708]. + +Requirements should be agreed between the manufacturer and customer. + +#### **A.4.5 Pneumatic resistance** + +If a gas pressurization system is used to protect non-water-blocked directly buried optical fibre cables, this test may be appropriate. + +The purpose of this test is to assure that an adequate amount of gas flow will pass through the cable. + +This test should be carried out in accordance with [IEC 60794-1-22] method F8. The specimen length and maximum pneumatic resistance should be according to a DS agreed between the manufacturer and customer. + +If the intent is to provide gas blocking in a cable, the referenced test method should be used with minimum pneumatic resistance criteria as agreed between the manufacturer and customer. + +#### **A.4.6 Freezing** + +Freezing testing comprises two related test methods applicable to optical fibre cables installed under environmental conditions in which freezing of the ground surrounding the cable or duct containing the cable may occur. The cases are a cable directly buried in the ground or similarly surrounded by a medium which can freeze. The latter is of most usefulness for directly buried cables (see clause 6.3.6). + +##### **A.4.6.1 Freezing in an unconfined space** + +This test is not often used for directly buried cable. The purpose of the external freezing test is to simulate freezing of the medium surrounding a directly buried cable, as in wet earth or water. + +This test should be carried out in accordance with method [IEC 60794-1-215] method F15A. + +Unless otherwise specified, the allowable change in attenuation when the cable is frozen should be: + +- $\leq 0.15$ dB/km at 1 550 nm. + +Unless otherwise specified, there should be no change in attenuation at ambient temperature after the test. + +#### **A.4.7 Material compatibility** + +This test method applies to directly buried cables installed under all environmental conditions in accordance with [IEC 60794-1-219]. This test may apply to all directly buried cables, but particularly applies to cables using polymeric gels or flooding compounds. Cables not utilizing the above should be tested as agreed between manufacturer and user, following the intent of this clause. + +This test method is intended to ensure compatibility of the cable materials (e.g., fibres, plastics, water blocking materials, and metals) over the cable's lifetime. The procedure simulates lifetime exposure by ageing a whole-cable specimen or selected elements of a cable at an elevated temperature over a period of time. Fibre and buffered fibre compatibility testing is addressed in clauses A.2.1 and A.2.3, which may be done in conjunction with this test. + +##### **A.4.7.1 Procedure for ageing** + +Ageing of completed cable specimens is under study. Control specimens for "before ageing" comparison or testing should be maintained. + +After ageing, the components should be removed from the cable or element assemblies and tested as follows. + +##### **A.4.7.2 Jacket tensile strength and elongation testing – after ageing** + +Jacket material tensile and elongation should be tested in accordance with [IEC 60811-501]. The aged jacket shall retain a minimum of 75% of its unaged tensile strength and elongation values. + +##### **A.4.7.3 Metal coatings delamination testing – after ageing** + +Plastic coatings on metal tapes should show no visual evidence of delamination. + +#### **A.4.8 Oxidative induction time, OIT – for polyolefin filling and jacket materials** + +Filling compounds and polyolefin-base jacket materials in all directly buried cables installed in all environmental conditions should be tested to assess the level of stabilization of the material. The oxidative induction time (OIT), test performs such an assessment using differential scanning calorimetry (DSC) techniques. + +The mass of the specimen should be per [ISO 11357-6]. A filling compound sample may be either from incoming material or from a finished cable. Jacket material should be from a finished cable or specifically manufactured simulated cable jackets. + +The specimen should be tested per [ISO 11357-6] with the following modifications and clarifications: + +- For filling compound – the test temperature should be $190\text{ }^{\circ}\text{C} \pm 0.5\text{ }^{\circ}\text{C}$ . +- For polyolefin jacket material – the test temperature should be $199\text{ }^{\circ}\text{C} \pm 1\text{ }^{\circ}\text{C}$ . +- The rate of heating of the test sample should be $10\text{ }^{\circ}\text{C/min}$ . +- An aluminium pan should be used in place of the copper crucible (pan). +- Screens should not be used. +- The torque rheometer is not required. + +The minimum OIT should be 20 minutes for filling compound or jacket material. + +#### **A.4.9 Hydrogen** + +This test method applies to optical fibre cable installed in a submarine environment or in higher atmospheric pressure applications. + +In the case of a metal-free cable or one employing a moisture barrier sheath with a selection of cable components which are low in the generation of hydrogen, either by themselves or in combination with others (for example, water), the build-up of hydrogen gas within the cable core will not lead to a significant increase in optical loss. + +For other cable constructions, [ITU-T L.126] and [b-IEC TR 62690] should be consulted. + +#### **A.4.10 Nuclear radiation** + +This test method assesses the suitability of optical fibre cables to be exposed to nuclear radiation. + +This test should be carried out in accordance with [IEC 60794-1-22] method F7. + +#### **A.4.11 Cable sheath adherence** + +This test applies to directly buried cables installed under all environmental conditions. A range of installation techniques can apply a frictional force to the outer jacket, which may cause the jacket to slip with respect to the underlying cable – either in tension or compression. + +The test is applicable to cables in which the jacket is not adhesively bonded to the underlying cable structure. Generally, these are dielectric or metallic cables without strength members in the jacket or armoured cables, all with flooding compound applied over the inner structure or the shield or armour. + +Cables which are not water blocked are also subject to this test. Cables using a bonded armour construction are not tested due to the inherently high longitudinal bond strength of such constructions. + +The test measures the resistance of the cable sheath components (shield or armour and the overlaying jacket) to separation, one from another, by measuring the force required to pull the cable core and metallic covering out of the jacket. + +Cables should be tested according to [IEC 61196-1-313] or following the intent, as modified below. The test should be at expanded ambient temperature per clause A.1.4. + +##### **A.4.11.1 Test procedure** + +In using the terminology of the referenced test method, the "conductor" or "outer conductor" should be the core assembly without the jacket. The "dielectric" or "sheath" should be the cable jacket. + +The tested specimen should be of sufficient length to provide the test length of $300\text{ mm} \pm 15\text{ mm}$ , per Figure A.1, and the prepared length of core and jacket. The prepared lengths of core and split jacket should be a length convenient for testing, generally about 100 mm each. The test may also be performed using the test plate of the referenced test rather than preparing the jacket. + +The test should be performed per [IEC 61196-1-313], as shown in Figure A.1. + +![Diagram of the sheath adherence test apparatus and sample. The diagram shows a cable sample with its jacket split into two halves. The inner conductor assembly is held by a knurled mandrel at the top, with an upward force F applied. The split jacket is held by a clamp at the bottom, with a downward force F applied. The test length is indicated as 300 mm (12 inches).](ef0e5cc71642e47e087e1a98d3f7b74c_img.jpg) + +The diagram illustrates the sheath adherence test setup. A cable sample is shown with its outer jacket split longitudinally into two halves at the top. The inner core assembly is gripped by a knurled mandrel at the top, and an upward force $F$ is applied. The split jacket halves are gripped by a clamp at the bottom, and a downward force $F$ is applied. The distance between the mandrel and the clamp, representing the test length, is labeled as 300 mm (12 inches). The diagram includes labels for 'Knurled mandrel', 'Cable sample', 'Clamp', '300 mm (12 inches)', 'F', 'Ç', and 'L.101(24)'. + +Diagram of the sheath adherence test apparatus and sample. The diagram shows a cable sample with its jacket split into two halves. The inner conductor assembly is held by a knurled mandrel at the top, with an upward force F applied. The split jacket is held by a clamp at the bottom, with a downward force F applied. The test length is indicated as 300 mm (12 inches). + +**Figure A.1 – Sheath adherence test apparatus and sample** + +##### **A.4.11.2 Requirements** + +The sheath adherence should have a value greater than 14 N/mm of the circumference of the inner surface of the jacket. That circumference is most conveniently measured as the outer circumference of the armour, shield, or underlying cable structure. + +### **A.5 Test methods for biotic characteristics** + +#### **A.5.1 Biotic damage** + +##### **A.5.1.1 Rodent and insect damage** + +Testing for resistance of directly buried cable to damage from rodent or insect attack should be as agreed between the manufacturer and customer (see clause 6.4). + +##### **A.5.1.2 Fungus resistance of jackets** + +Fungus evaluation is applicable to cables installed in all environmental conditions. Polyethylene jacket materials commonly used in directly buried cables are inherently non-nutritive to fungus. Other jacket materials, including those which may be applied for fire rated cables or as outer jackets, may require evaluation for fungus resistance. + +The test methods and requirements should be as agreed between manufacturer and user. [ITU-T L.161] may be consulted for guidance. Test methods for assessing fungus resistance are under development in IEC. + +### **A.6 Test methods for electrical characteristics** + +#### **A.6.1 Lightning** + +While of secondary importance to directly buried cables, lightning testing should be considered (see clause 6.5.1). + +When a metallic material is used as a cable element, the lightning protection of a cable may undergo a test described in [ITU-T K.47], subject to agreement between the customer and manufacturer. + +#### **A.6.2 Electrical continuity** + +The electrical continuity test is to verify that cable metallic elements are electrically continuous throughout the cable. This test is important for bonding and grounding, toning for location, and other related system issues. Typically, the test should check continuity and should carry no resistance or conductivity requirement. The metallic elements may be tested individually or may be tested as a total group. Since this latter criterion is frequently the case, all elements are to be measured as a group unless specified otherwise. + +The test should be performed per [IEC 60794-1-403]. All metallic elements on the test should be electrically continuous. + +## Bibliography + +- [b-ITU-T L.110] Recommendation ITU-T L.110 (2017), *Optical fibre cables for direct surface application.* +- [b-ITU-T G-Sup.40] ITU-T G-series Recommendations – Supplement 40 (2024), *Optical fibre and cable Recommendations and standards guideline.* +- [b-ITU-T TR.ofcs] ITU-T Technical Report TR-OFCS (2015), *Optical fibres, Cables and Systems.* +- [b-IEC TR 62690] IEC TR 62690 (2014), *Hydrogen effects in optical fibre cables – Guidelines.* +- [b-IEC TR 62691] IEC TR 62691 (2016), *Optical fibre cables – Guidelines to the installation of optical fibre cables.* +- [b-IEC TR 63194] IEC TR 63194 (2019), *Guidance on colour coding of optical fibre cables.* + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1011-202509-I_PDF-E/007b053fe94a8348f75128a584503fd0_img.jpg b/marked/L/T-REC-L.1011-202509-I_PDF-E/007b053fe94a8348f75128a584503fd0_img.jpg new file mode 100644 index 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b/marked/L/T-REC-L.1020-201801-I_PDF-E/raw.md @@ -0,0 +1,282 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.1020** + +(01/2018) + +SERIES L: ENVIRONMENT AND ICTS, CLIMATE +CHANGE, E-WASTE, ENERGY EFFICIENCY; +CONSTRUCTION, INSTALLATION AND PROTECTION +OF CABLES AND OTHER ELEMENTS OF OUTSIDE +PLANT + +--- + +**Circular economy: Guide for operators and +suppliers on approaches to migrate towards +circular ICT goods and networks** + +Recommendation ITU-T L.1020 + +# ITU-T L-SERIES RECOMMENDATIONS + +## **ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT** + +| | | +|--------------------------------------------------------|-------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node elements (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +## Recommendation ITU-T L.1020 + +# Circular economy: Guide for operators and suppliers on approaches to migrate towards circular ICT goods and networks + +## Summary + +Recommendation ITU-T L.1020 suggests approaches of circular economy (CE) for information and communication technology (ICT) goods and networks. It focuses particularly on the next steps in improving circularity in the operators' supply chain. + +The Recommendation provides a guide on how operators could work with their supply chain to improve CE aspects for ICT goods and networks but it does not provide metrics. The objective of the guide is to provide options to improve circularity and to enable operators and their suppliers to create business models for the promotion of circular networks for an optimum solution that uses all the loops of circularity – from sharing to recycling. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.1020 | 2018-01-13 | 5 | 11.1002/1000/13457 | + +## Keywords + +Circular economy, end-user goods, guideline, ICT, infrastructure, ICT goods, ICT networks. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2018 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-----------------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 1 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 2 | +| 6 Circular economy: Guideline on how to migrate to circular ICT goods and networks..... | 2 | +| 6.1 Background..... | 2 | +| 6.2 Way forward ..... | 2 | +| Annex A – Manifesto ..... | 4 | +| A.1 Goals and ambitions ..... | 4 | +| A.2 How to change towards a circular business model..... | 4 | +| A.3 Implementation..... | 5 | +| Bibliography..... | 6 | + + + +## Recommendation ITU-T L.1020 + +# Circular economy: Guide for operators and suppliers on approaches to migrate towards circular ICT goods and networks + +# 1 Scope + +This Recommendation suggests approaches of circular economy (CE) for the information and communication technology (ICT) goods. It focuses particularly on the next steps in improving circularity in the operators' supply chain. + +The Recommendation provides a guide on how operators could work with their supply chain to improve CE aspects for ICT goods and networks through a *manifesto* intended to improve the circularity of products through supply chain actions. The objective of the guide is to provide options to improve circularity and to enable operators and their suppliers to create business-models for the promotion of circular networks for an optimum solution using all the loops from sharing to recycling. Thus the proposed manifesto can be used by operators and their suppliers to improve the circularity of all ICT goods and networks, both for infrastructure and end-user goods. + +This Recommendation does not outline metrics, but is intended to be used as a guide for operators to work jointly with suppliers to improve circularity. + +This Recommendation builds upon Supplement 28 to the ITU-T L-series of Recommendations [b-ITU-T L-Sup.28] and the corresponding ETSI report [b-ETSI EE TR 103 476] which cover CE as used in the ICT industry and existing CE metrics, as well as examples of their use. + +# 2 References + +None. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following term defined elsewhere: + +**3.1.1 e-waste** [b-UNEP-12/5]: Electrical or electronic equipment that is waste, including all components, sub-assemblies and consumables that are part of the equipment at the time the equipment becomes waste. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following term: + +**3.2.1 circular economy:** A circular economy is restorative and regenerative by design, and aims to keep products, components, and materials at their highest utility and value at all times while reducing waste streams. + +A concept that distinguishes between technical and biological cycles, the circular economy is a continuous, positive development cycle. It preserves and enhances natural capital, optimises resource yields, and minimises system risks by managing finite stocks and renewable flows, while reducing waste streams. + +(NOTE – The definition is based on [b-EMF], and amended.) + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|------------------------------------------| +| CE | Circular Economy | +| ICT | Information and Communication Technology | +| KPI | Key Performance Indicators | +| UNEP | United Nations Environment Programme | + +# **5 Conventions** + +None. + +# **6 Circular economy: Guideline on how to migrate to circular ICT goods and networks** + +## **6.1 Background** + +ICT services will be key to enable energy reduction and dematerialization in society, for instance by reducing fuel consumption due to reduced travelling, and by decreasing the use of materials through cloud services. For example, services such as video-on-demand reduce the use of CDs and DVDs. + +At the same time, ICT goods and networks use energy and materials, therefore in order to reduce the use of resources and to reduce e-waste as much as possible, it is necessary to consider their full life cycle. + +To achieve circularity, focus is not only on reuse and recycling, but also on the design of the products. Designs based on circular principles will be improved and promoted when this is seen as a vital step in the whole supply chain, not only by operators and end-users but also by producers and their sub-contractors. + +The following mechanisms lead to increased resource efficiency and reduce e-waste production to contribute to the CE: + +- a) increased usage rate by sharing or virtualization; +- b) extended operating life time of equipment by simplified maintenance and reuse; +- c) reuse/redistribution for equipment or components on other type of function or in other countries; +- d) refurbishment and remanufacturing; and +- e) recycling of all materials without using landfill or incineration at the final stage. + +## **6.2 Way forward** + +To promote a circular economy, it is necessary to define a framework and scenarios to reduce the use of new materials or to migrate to reused raw materials. This will avoid using new raw materials extracted from mines. In other words, efforts should be made not to take more from the earth than what could be recovered. In an ideal world, ICT infrastructure equipment would not use virgin materials and during production only renewable energy would be used. At the end of the life cycle all materials would be recovered through reuse or recycling. + +Operators should be able to choose equipment not only based on the quality of the services but also based on the contribution to circularity. To realize circularity, focus should not be on the reuse and recycling only, but it starts with the design of the products. Designs based on circular principles will be improved if this is seen as a vital step forward in the whole supply chain. This refers not only to operators, but also their suppliers including sub-contractors and even end-users in order to promote the use of reused materials. + +Also, a first step to move towards circular ICT goods can be paved by an agreement amongst operators and suppliers in the form of a *manifesto* intended to improve the circularity of products through supply chain actions. The first version of such a manifesto is described in Annex A. This manifesto can be used by operators and their suppliers to improve the circularity of all ICT goods and networks, both for infrastructure and end-user goods. + +# Annex A + +### Manifesto + +(This annex forms an integral part of this Recommendation.) + +## A.1 Goals and ambitions + +- 1) It is desirable that business operations minimize their material impact on the planet and its natural resources, in an endeavour not to deplete them further and to remain within the limits of what the planet can generate or restore by itself. +- 2) Operators should aim to reduce the material impact of products and services. This implies that all new equipment installed in networks and data centres, and all end-user goods should become almost fully circular. This implies that almost all the materials should be reused or recycled. To achieve circularity, it is necessary to use fewer materials in equipment, increase the operating lifetime of goods and, wherever possible, switch to more sustainable materials. Minimizing the impact on the planet calls for a balance between a longer operating lifetime and the renewing of ICT goods and networks with more energy efficient products, possibly based on new and more sophisticated materials. +- 3) This manifesto is drawn up between operators and suppliers to achieve the circularity of goods, networks and services. The manifesto expresses the commitments to actions that are needed to develop value chain collaborations to transfer the industry into a circular business model by using less virgin raw materials, extend operating lifetime, reuse and recycle all products and improve energy efficiency as much as possible. +- 4) With this manifesto, operators and suppliers take the joint responsibility of reaching these circular goals and ambitions. + +## A.2 How to change towards a circular business model + +To realize the objective of achieving close to 100% circularity, parties jointly agree to, when economically viable, develop circular projects considering the following four focus points: + +- 1) Reduce: Reduce the use of virgin raw materials through: + - 1.1) Virtualization; further virtualization and automation of networks to reduce the environmental footprint; + - 1.2) Migration to software- and service-based business models rather than hardware-models; + - 1.3) Dematerialization; i.e., dematerialization of DVDs, CDs and newspapers by replacing them with connectivity-enabled digital media; and + - 1.4) Using recycled and bio-based materials; extend the use of recycled and bio based materials where possible. +- 2) Extend: Extend the use of products for a longer operating lifetime and use them more efficiently: + - 2.1) Extend the lifetime of goods and networks by designing them for a longer operating life time; + - 2.2) Increase or optimize rates of utilization; and + - 2.3) Minimize the impact on the planet by finding a balance between the longer operating lifetime and the introduction of more energy efficient ICT goods, possibly based on new and more sophisticated materials. +- 3) Reuse and Recycle: Improve second life of products and materials + - 3.1) Use of goods and or materials that have been designed to be recycled (i.e., designed with a life cycle perspective in mind); + +- 3.2) Increase the reuse of products as reuse by customers or suppliers is the best choice for returned goods to expand the total lifetime; +- 3.3) Reuse could take place in the country where the product was originally purchased or in another country. In case the product is reused in another country, the company that sends the product to the other country should properly track that the end-of-life treatment of the product is taken care of as it would have been at the original place of usage. If the other country does not have proper end-of-life treatment facilities, the product should be shipped elsewhere for proper treatment; +- 3.4) Repair and refurbishment of returned goods and goods intended for reuse should be arranged in a way that supports the circularity; +- 3.5) Choose reuse over recycling when possible; and +- 3.6) Landfill should be avoided as much as possible. +- 4) Energy Efficiency + - 4.1) Parties should investigate ways to further enhance the energy efficiency of network infrastructure and end-user equipment. + +## **A.3 Implementation** + +The parties will jointly develop initiatives for a circular business model, including implementation, planning and performance, such as: + +- 1) Undertake joint studies with operators and suppliers to investigate new business models to contribute to a more circular economy; +- 2) Draw up a list of initiatives to achieve circular goals and setting joint goals on current initiatives; +- 3) Plan quarterly meetings to monitor progress on circular initiatives; and +- 4) Set up, select and monitor key performance indicators (KPIs) on circular goals. + +# Bibliography + +- [b-ITU-T L-Sup.28] ITU-T L-series of Recommendations – Supplement 28 (2016), *Circular economy in information and communication technology; definition of approaches, concepts and metrics.* +- [b-ETSI EE TR 103 476] ETSI EE TR 103 476 (2017), *Circular Economy (CE) in Information and Communication Technology (ICT); Definition of approaches, concepts and metrics.* +- [b-EMF] Ellen MacArthur Foundation +<> +- [b-UNEP-12/5] UNEP/CHW.12/5/Add.1/Rev.1 +<> + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1022-201910-I_PDF-E/8a597e344d10e36bbb2f243f6c4e74c6_img.jpg b/marked/L/T-REC-L.1022-201910-I_PDF-E/8a597e344d10e36bbb2f243f6c4e74c6_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..e48b057b788e68c70d19c78601212fc3da792880 --- /dev/null +++ b/marked/L/T-REC-L.1022-201910-I_PDF-E/8a597e344d10e36bbb2f243f6c4e74c6_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:6648360e2184d5fd675d72b5ba030fe73200fa01a4ac96f660e4f05c5c80ba30 +size 44852 diff --git a/marked/L/T-REC-L.1022-201910-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg b/marked/L/T-REC-L.1022-201910-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..827609df9ad8667ae079f875841506349f063390 --- /dev/null +++ b/marked/L/T-REC-L.1022-201910-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:c0d2afb537db9f3588854962a991eb1178220b2bbb8ff3cea6712979a53a864b +size 4107 diff --git a/marked/L/T-REC-L.1022-201910-I_PDF-E/raw.md b/marked/L/T-REC-L.1022-201910-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..af7518fe3538ad8c2069312d14d94fc9a52bf7da --- /dev/null +++ b/marked/L/T-REC-L.1022-201910-I_PDF-E/raw.md @@ -0,0 +1,1141 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.1022** + +(10/2019) + +SERIES L: ENVIRONMENT AND ICTS, CLIMATE +CHANGE, E-WASTE, ENERGY EFFICIENCY; +CONSTRUCTION, INSTALLATION AND PROTECTION +OF CABLES AND OTHER ELEMENTS OF OUTSIDE +PLANT + +--- + +**Circular economy: Definitions and concepts for +material efficiency for information and +communication technology** + +Recommendation ITU-T L.1022 + +# ITU-T L-SERIES RECOMMENDATIONS + +## **ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT** + +| | | +|--------------------------------------------------------|-------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node elements (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +## Recommendation ITU-T L.1022 + +# Circular economy: Definitions and concepts for material efficiency for information and communication technology + +## Summary + +Recommendation ITU-T L.1022 contains a guide to the circular economy (CE) aspects, parameters, metrics and indicators for information and communication technology (ICT) based on current approaches, concepts and metrics of the CE as defined in existing standards, while considering their applicability for ICT. + +In this Recommendation ICT is defined based on the definition given by the Organisation for Economic Co-operation and Development (OECD) (See [b-ISIC] in the Bibliography). + +This Recommendation discusses the special considerations and challenges in a broader and more in-depth context for all ICT defining parameters, metrics and indicators with the intention to guide the vertical standardization of material efficiency for ICT. + +The guidelines aim to examine the kinds of standards that are available and to assess their relevance for ICT product groups citing examples of interrelated relevance throughout the text of the Recommendation. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.1022 | 2019-10-22 | 5 | 11.1002/1000/13962 | + +## Keywords + +Aspects, circular economy, concepts, ICT, information and communication technology, metrics + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2019 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-----------------------------------------------------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 3 | +| 4 Abbreviations and acronyms ..... | 4 | +| 5 Conventions ..... | 5 | +| 6 Introduction to circular economy concepts..... | 5 | +| 7 Circular-economy-related legislation and standards ..... | 6 | +| 7.1 Emerging regulations and standards..... | 7 | +| 7.2 Voluntary certification schemes ..... | 10 | +| 8 Circular economy business models ..... | 11 | +| 9 Circular economy aspects and parameters affecting the environmental impact in different life-cycle stages..... | 12 | +| 9.1 Raw material acquisition stage ..... | 12 | +| 9.2 Use stage..... | 14 | +| 9.3 End-of-life stage ..... | 17 | +| 10 Circular economy on an organizational level ..... | 18 | +| 10.1 Reduction and reuse of production scrap ..... | 19 | +| 10.2 Operating with renewal energy ..... | 19 | +| 10.3 Transportation..... | 19 | +| 10.4 Reduction of water usage ..... | 19 | +| 10.5 IoT enabled circularity ..... | 19 | +| 10.6 Studies examining monitoring and control services with sensors and ICT infrastructure focused on waste management..... | 20 | +| 10.7 Take-back models reverse return logistics ..... | 20 | +| 10.8 AI enabled circularity ..... | 20 | +| 10.9 Wider system considerations ..... | 20 | +| 10.10 Circular economy in new network equipment acquisition process ..... | 21 | +| 11 Reporting ..... | 21 | +| 12 Insights and conclusions ..... | 22 | +| Bibliography..... | 23 | + +## Introduction + +In order to facilitate a shift to a more sustainable economy, a circular economy (CE) has been proposed as one of the main ways forward. Improving the resource efficiency (RE) of products is important in order to promote a transition towards a more circular economy in the EU and beyond. This can be supported, for example, through a series of measures aiming to manufacture goods that are more durable, easier to repair, reuse or recycle. Improving certain material efficiency metrics of products might be important to reduce their environmental impact. Particularly, an improvement of the durability of goods can have the potential of bringing added value to the environment and to the economy by limiting the early replacement of goods and thus saving resources. However, the design of products needs to be assisted by appropriate assessment methods. + +ITU-T has made preliminary descriptions of RE for ICT goods [b-ITU-T L-Sup.5] and [b-ITU-T L-Sup.28], which have been considered in the development of this Recommendation which focuses on the applicability of CE metrics for ICT. + +## Recommendation ITU-T L.1022 + +# Circular economy: Definitions and concepts for material efficiency for information and communication technology + +## 1 Scope + +This Recommendation provides a guide to the aspects of circular economy (CE), parameters, metrics, indicators for ICT based on current approaches, concepts and metrics of the CE as defined in existing standards, while considering their applicability for ICT. It is necessary to distinguish between CE concepts for product design and maintenance and general concepts aiming at the corporate practices of ICT companies. + +The scope of the Recommendation, in addition to the above context, includes the following aspects: + +- reparability +- durability +- reusability +- recyclability +- recoverability +- refurbish ability +- remanufacture ability +- upgradeability. + +The following parameters, indicators and metrics are related: + +- recycled and renewable content +- use of critical raw materials +- ability to reuse parts/components/materials +- quality of recycling. + +This Recommendation is a framework standard that covers aspects that will be elaborated in future Recommendations. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T L.1021] Recommendation ITU-T L.1021 (2018), *Extended producer responsibility – Guidelines for sustainable e-waste management*. + +## 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 bio-based plastic [b-BioBag2]:** Plastic that is made by plant material. + +**3.1.2 biodegradable plastic** [b-BioBag1]: A plastic capable of undergoing biological, anaerobic or aerobic degradation leading to the production of CO2, H2O, methane, biomass, and mineral salts, depending on the environmental conditions of the process. + +**3.1.3 component** [b-ETSI TR 103 679]: Part of a product that cannot be taken apart without destruction or impairment of its intended use. + +**3.1.4 compostable plastic** [b-EN 13432]: Biodegradable/compostable plastic that completely decomposes in a composting setting in a specific time frame, leaving no harmful residues behind. + +**3.1.5 corrective maintenance** [b-prEN 45554]: See Repair. + +NOTE – An example is a fan filter exchange. + +**3.1.6 critical raw material (CRM)** [b-EN 45558]: Materials which, according to a defined classification methodology, are economically important, and have a high-risk associated with their supply. + +NOTE – For the purpose of this Recommendation, CRMs are the ones listed in Annex 1 of [b-COM CRM]. Future updates to this list will apply and replace former versions of this list. + +**3.1.7 disassembly** [b-IEC 62452], [b-prEN 45554]: Process whereby a product is taken apart in such a way that it could subsequently be reassembled and made operational. + +**3.1.8 durability** [b-prEN 45552]: Ability to function as required, under defined conditions of use, maintenance and repair, until a final limiting state is reached. + +NOTE 1 – The degree to which maintenance and repair are within scope of durability will vary by product or product group. + +NOTE 2 – The final limiting state has to be defined by the user of [b-prEN 45552]. + +**3.1.9 important change** [b-prEN 45553]: Modification which influences the safety, original performance, purpose or type of the product. + +NOTE 1 – Refer to the EU Blue Guide [b-Blue] for conditions under which a product has to be considered as a new product when placing on the market after such changes. + +NOTE 2 – The person who carries out the changes becomes then the manufacturer with the corresponding obligations. + +**3.1.10 limiting event** [b-prEN 45552]: Event which results in a primary or secondary function no longer being delivered. + +NOTE – Examples of limiting events are failure, wear-out failure or deviation of any analogue signal. + +**3.1.11 limiting state** [b-prEN 45552]: Condition after one or more limiting event. + +**3.1.12 maintenance** [b-prEN 45552]: Action carried out to retain a product in a condition where it is able to function as required. + +NOTE – Examples of such actions include inspection, adjustments, cleaning, lubrication, testing, and replacement of worn-out parts. Such actions could be performed by users in accordance with instructions provided with the equipment (e.g., replacement or recharging of batteries); or the actions could be performed by service personnel in order to ensure that parts with a known time to failure are replaced in order to keep the product functioning. + +**3.1.13 material** [b-EN 62474]: Substance or mixture of substances within a product or product part. + +**3.1.14 oxo-degradable plastic** [b-BioBoxo]: Plastic that breaks into fragments in the presence of oxygen. + +**3.1.15 part** [b-prEN 45552]: Hardware or software constituent of a product. + +**3.1.16 product** [b-ETSI TR 103 679]: Goods or services. + +**3.1.17 recoverability** [b-prEN 45555]: Ability of a waste product to be recovered. + +**3.1.18 recoverability rate** [b-prEN 45555]: Ratio of the sum of recoverable products, product parts, materials mass to total waste product mass reprocessed. + +**3.1.19 recovery** [b-EU WFD]: Any operation the principal result of which is waste serving a useful purpose by replacing other materials which would otherwise have been used to fulfil a particular function, or waste being prepared to fulfil that function, in the plant or in the wider economy. + +**3.1.20 recyclability** [b-prEN 45555], [b-IEC62635]: Ability of a product to be recycled at end-of-life. + +**3.1.21 recycled material content** [b-prEN 45557]: Proportion, by mass, of secondary material in a product. + +**3.1.22 recycling** [b-EU WFD]: Any recovery operation by which waste materials are reprocessed into products, materials or substances whether for the original or other purposes. It includes the reprocessing of organic material but does not include energy recovery and the reprocessing into materials that are to be used as fuels or for backfilling operations. + +**3.1.23 refurbish** [b-prEN 45553]: Returning by industrial process a used product to a satisfactory working condition without making any important changes to the product. + +**3.1.24 reliability** [b-prEN 45552]: Probability that a product functions as required under given conditions, including maintenance, for a given duration without failure. + +NOTE 1 – The intended function(s) and given conditions are described in the user instructions provided with the product. + +NOTE 2 – Duration can be expressed in units appropriate to the part or product concerned, e.g., calendar time, operating cycles, distance run, etc., and the units should always be clearly stated. + +**3.1.25 remanufacturing** [b-prEN 45553]: Industrial process which creates a product from used products or used parts where at least one important change is made to the product. + +**3.1.26 repair** [b-prEN 45554]: Process of returning a faulty product to a condition where it can fulfil its intended use. + +**3.1.27 reuse** [b-EU WFD]: Operation by which products or parts that are not waste are used for the same purpose for which they were conceived by another user. + +NOTE – The transfer of ownership is an essential part of the concept of reuse. + +**3.1.28 substance** [b-REACH]: Means a chemical element and its compounds in the natural state or obtained by any manufacturing process, including any additive necessary to preserve its stability and any impurity deriving from the process used, but excluding any solvent which may be separated without affecting the stability of the substance or changing its composition. + +**3.1.29 substances of concern** [b-EUCOM32]: Hazardous to humans or the environment, present in products sold before they were restricted, have a long lifetime, are costly to detect or remove, create obstacles in particular for recycling. + +**3.1.30 upgrade** [b-prEN 45554]: Process to enhance the functionality, performance, capacity or aesthetics of a product. + +NOTE – Upgrade may involve changes to the software, firmware and/or hardware. IEC 62075:2012, definition 3.23, Note added in [b-prEN 45554]. + +### **3.2 Terms defined in this Recommendation** + +This Recommendation defines the following terms: + +**3.2.1 benefit rate**: Potential savings that can be achieved over status quo. + +NOTE – Some examples include the following: + +- "Potential environmental savings that can be achieved from recycling certain parts of the product over the environmental burdens of production of primary materials, manufacturing, use and disposal of the product" [b-ArdenteR]. +- "Potential cost savings that can be achieved from reusing certain parts over the costs due to the production of primary materials, manufacturing, use and disposal of the product" [b-ArdenteR]. + +**3.2.2 preventive maintenance:** Preventive action carried out to retain a product in a condition where it is able to function as required. Adapted from [b-prEN 45552]. + +NOTE – e.g., cleaning. + +**3.2.3 recyclability rate:** The ratio of the sum of recyclable products, product parts, materials mass to total waste product mass reprocessed. + +**3.2.4 renewable material:** Natural material which can replace materials depleted by usage and consumption either through natural reproduction other reoccurring processes in a finite amount of time in a human time scale. + +**3.2.5 reparability:** The ability of a product to be repaired. + +**3.2.6 reused component:** A hardware constituent of a product that cannot be taken apart without destruction or impairment of its intended use, which is used again with or without alteration. + +**3.2.7 single-use plastic product:** A product that is made wholly or partly from plastic and that is not conceived, designed or placed on the market to accomplish, within its lifespan, multiple trips or rotations by being returned to the producer for refill or reused for the same purpose for which it was conceived. + +NOTE – Single-use plastic products include a diverse range of commonly used fast-moving consumer products that are discarded after having been used once for the purpose for which they were provided, are rarely recycled, and are prone to littering. + +**3.2.8 single-use plastics:** Any disposable plastic items, i.e., packaging or a consumer product that are thrown away after one brief use, not intended for longevity, reuse or recycle. + +**3.2.9 upgradeability:** The ability of a product to be upgraded. + +## 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|------------------------------------------| +| AI | Artificial Intelligence | +| CE | Circular Economy | +| CRM | Critical Raw Material | +| EPR | Extended Producer Responsibility | +| FMEA | Failure Mode and Effect Analysis | +| ICT | Information and Communication Technology | +| IHS | Integrated Heat Spreader | +| LCA | Life Cycle Assessment | +| LCC | Life Cycle Cost | +| LCI | Life Cycle Inventory | +| ME | Material Efficiency | +| MTBF | Mean Time Between Failures | +| PSS | Product Service System | + +RE Resource Efficiency + +SUP Single Use Plastics + +## 5 Conventions + +None. + +## 6 Introduction to circular economy concepts + +Circular economy (CE) covers the full life cycle of both goods and business models. + +Most business models are linear cradle-to-grave; that is, extracting, manufacturing, using and wasting. This usually turns 90% of the resources extracted from nature into waste [b-Thomas]. + +In general CE is about closing the loop between different life cycles through design and corporate actions/practices that enable recycling and reuse in order to use raw materials, goods and waste in a more efficient way and to increase energy performance. Thus CE is associated with strategies to minimize the input of primary materials and keep goods out of landfill and incineration. This is important as research has shown that the toxicity of waste mobile phones increased with technology innovation for phones produced from 2002 to 2013 [b-Chen]. CE deals with both environmental and economic aspects. In an ideal CE, all waste generated would be reused as raw material in production processes. Discarded goods represent a valuable source of materials. + +NOTE – In order to be environmentally beneficial, CE strategies would need to be catered for the full life cycle of a given product category [b-Trusty]. + +Resource efficiency (RE) is sometimes used interchangeably with the CE concept. However, RE focuses more on the efficient use of resources and on minimizing the environmental impact of a good during its life cycle [b-Hamakawa]. An example of a generalized RE definition is dealing with the benefits obtained from the use of natural resources. Furthermore, materials efficiency (ME) is used in parallel with RE, or as a more precise concept dealing with raw materials only, excluding energy. In this Recommendation, RE is seen as a subcategory of CE and ME as a part of RE. + +CE and RE aspects and parameters/metrics/indicators suitable for ICT are also discussed. + +There are many examples of attempts to model different CE aspects of ICT [b-Hamakawa], [b-Talens], [b-Harivard], [b-Schischke], [b-Dimitrova], [b-Nissen], [b-Ardente], and [b-Andrae]. However, these efforts start from a bottom-up perspective and are potentially helpful in the production specific standardization of certain ICT applications. In case such standardization happens, it is intended to follow the guidelines of this Recommendation. + +Previously, ITU-T [b-ITU-T L-Sup.28] attempted to provide an understanding of the scope and limitations of particular existing resource efficiency indicators in order to assist policy makers and the scientific community in the application and further development of indicators. This Recommendation builds on that information taking into account recent progress in other standards. + +Through the design stage, it is possible to influence all the most important aspects, minimizing material usage and environmental impacts. Goods can be designed for increased lifespans, as well as to be repaired, upgraded, reused, refurbished, remanufactured and/or eventually recycled instead of being thrown away. However, in practice trade-offs have to be made with parameters such as safety aspects, reliability, phase out of specific substances (e.g., those dangerous to human health and the environment or which are detrimental in recycling processes) and cost. One important point of view is to avoid the use of hazardous materials and optimize the use of rare earth materials when possible. + +This can lead to situations where recycling and reuse can be hampered by the presence of certain chemicals which were tolerated in the past, but are prohibited in current legislations. + +In addition to reducing the materials, the focus is on energy usage during the whole life cycle of goods, which means improved efficiency in the production and use stages. + +Table 1 shows a summary of CE aspects, the level of disassembly and the expected quality of the ICT good after CE related actions. + +**Table 1 – CE aspects for ICT goods, level of disassembly and expected quality** + +| CE aspect | Level of disassembly of ICT goods | Expected quality of ICT goods | Examples | +|--------------------------|-----------------------------------|-------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Maintenance (preventive) | None | Working order | Replace fan filter | +| Maintenance (corrective) | ICT goods down to faulty part | Working order | Replace damaged mobile phone display | +| Upgrade | None if software | Working order | Software upgrades | +| Repair | ICT goods down to faulty part | Working order | Replace damaged mobile phone display | +| Reuse (direct) | None | "As-is" | Operators can directly reuse base stations in another location | +| Refurbish | Good or module | Specified level | Set-top-box gateway are refurbished by combining parts from different set-top-box gateway goods. Another example is used laptops: inspection for functionality, replacement of parts where necessary. | +| Remanufacture | Part | 'Like-new part' | Set-top-box gateways are remanufactured in several ways by upgrading the Wi-Fi module to a better performance standard. | +| Recycle | Recyclable streams | – | Gold recycling | +| Recover | Non-recyclable parts/materials | – | Energy recovery from plastics | + +## 7 Circular-economy-related legislation and standards + +A number of specific policy measures and regulations have already been established that are intended to support the transformation to the CE. + +Within the CE area, there is ongoing work on e-waste in ITU-T which includes studies of circular economy metrics for ICT. + +For example, the publication of [ITU-T L.1021] on EPR. + +IEC has developed standards covering the reliability of goods [b-IEC 62380]. Moreover IEC released a standard for environmental conscious design of EEE [b-IEC 62430] where it is recommended, among many other things, to consider reducing material complexity in order to make material recycling easier. + +The European Union and its Member States previously introduced extended producer responsibility legislation for various waste streams including WEEE, waste batteries and waste packaging. + +EU Directive 2012/19/EU on waste electrical and electronic equipment [b-WEEE] introduced annual minimum collection rates requesting Member States to separately collect and treat WEEE at least at a ratio of 65% of the average weight of EEE placed on the market in the previous three years or alternatively 85% of the total WEEE volumes generated in the country. Choosing the latter rate would also require Member States to develop methods how to calculate and assess the total volumes of WEEE that are generated in the country. + +[b-ETSI TR 103 476] on the circular economy in ICT was part of the work done under EU Mandate 543. + +On a national level, British Standards prepared the BS 8001 standard for implementing circular economy in organizations [b-BS 8001]. + +Moreover, Austrian Standards has released a publicly available specification, ONR 192102 that aims to enable long-lived and repairable electronic goods [b-Austria]. + +Other existing standards are the European standard [b-EN50614], the British standard [b-PAS 141:2011], the German 63 standard [b-VDI 2343] and the Flemish standard entitled *Code of Good practice for re-use of (W) EEE* [b-Flem]. + +### 7.1 Emerging regulations and standards + +#### 7.1.1 EU Mandate 543 + +CEN-CENELEC published its first two standards in the first quarter of 2019, [b-EN 45558] and [b-EN 45559]. + +Overall, CEN-CENELEC targets to develop eight horizontal standards and two technical reports giving generic principles for addressing the material efficiency of ErPs [b-CEN-CLC]. The scope of these standards are explained below. + +Currently CEN-CENELEC forecasts to vote on the documents in the second half of 2019, thus publications can be expected in 2020. + +##### *prEN 45552 Durability:* + +This document defines parameters and methods as a framework in order to assess the durability of ErP. + +The prEN45552 standard refers to [b-IEC 61123] and [b-IEC 61124] for the durability "measurement". + +##### *prEN 45553 Remanufacture and refurbish:* + +This document proposes a general method to assess the ability of ErPs to be remanufactured on a generic level. Where a good specific standard for assessing the ability to remanufacture does not exist, this document can be used for such an assessment. The assessment of the ability of parts to be remanufactured is not considered in this document. + +##### *prEN 45554 Repair, reuse, upgrade:* + +This document provides generic methods to assess the following aspects: + +- the ability to repair products; +- the ability to reuse products, or parts thereof; +- the ability to upgrade products. + +It includes generic criteria and methods relevant for assessing the ability to access or remove certain parts from products for the purpose of repair, reuse or upgrading. + +The criteria and methods in this document focus on the design of the product and related conditions when the product is placed on the market, taking into account knowledge of parts that are likely to fail, need replacing, or have reuse potential. + +##### *prEN 45555: Recycle and recover:* + +This document establishes general principles for: + +- assessing the recyclability of energy-related products; +- assessing the recoverability of energy-related products. + +This document also considers: + +- the ability to access or remove certain components, assemblies, materials or substances from products to facilitate their extraction at the EoL for ease of treatment, recycling and other recovery operations; +- the recyclability of critical raw materials from energy-related products. + +##### *prEN 45556: Reused components:* + +This document deals with the assessment of the proportion of reused components in energy-related products on a generic level, which can be applied at any point in the life of the product. This document can be applied where no product-specific standard exists. Aspects such as performance, validation, verification and suitability of reused components are not in the scope of this document. + +The reused part rate is declared by manufacturer based on evidence documentation. Reused component index can be calculated. + +##### *prEN 45557: Recycled material content:* + +This document provides a general method for assessing the proportion of secondary material in an energy-related product, its parts or material(s). This document is applicable as the framework to be used for defining the assessment of recycled material content in specific product groups. However, in absence of product specific standards it can be applied directly. This document does not apply to the assessment of reused components. + +The recycled content is declared by the manufacturer based on evidence documentation. + +##### *EN 45558: CRM content:* + +The main intended use of this document is to provide a means for information on the use of CRMs to be exchanged across the supply chain and with other relevant stakeholders. Potential users of this document are any public, private or social enterprises involved in the production of ErP, such as manufacturers of energy-related products (including SMEs) and other organizations in the product supply chain. It is also relevant to European market surveillance and trade authorities as well as European policy makers. This document is horizontal in nature, and can be applied directly to any type of energy-related product. + +This document proposes a standardized format for reporting the use of CRMs in energy-related products by applying the IEC 62474 [b-EN 62474] materials declaration standard. However, this document does not provide or determine any specific method or tool to collect CRM data. Process chemicals, emissions during product manufacturing and packaging are not in scope of this document. + +The CRM content is declared by the manufacturer based on evidence documentation. + +##### *EN 45559: Information related to material efficiency aspects:* + +This document aims to set up a general method for the communication of material efficiency (ME) aspects of energy-related products (ErP). It is intended to be used as an input for the development of a communication strategy in horizontal, generic, product-specific, or product-group publications. This document relates to the standards in the range of "prEN 45552 – 7", and "EN45558 – 9" developed under the standardization request M/543 [b-M543]. While the other standards will provide + +methods to assess or measure specific ME topics, this document focuses on the communication of the various topic-related content. Legislation can require that ME information is provided to specific intended audience and is verifiable, accurate, relevant and not misleading. Therefore, this document requests that the intended audiences (end users, professionals or market surveillance authorities) are taken into account, as well as the means of communication and media for providing the ME information. + +ETSI-EE might make an adjusted standard – based on CENELEC standards - for infrastructure goods (mainly mobile base stations, switches, routers and servers). + +#### **7.1.2 EU strategy for plastics in the circular economy** + +In December 2015, the Commission adopted an EU Action Plan for a circular economy [b-ECPIAP]. It identified plastics as a key priority and committed itself to prepare a strategy to address the challenges posed by plastics throughout the value chain and taking into account the entire life cycle. + +The goal of the EU strategy is to ensure that all plastic packaging is recyclable by 2030. + +#### **7.1.3 EU action plan for the circular economy** + +Extended producer responsibility (EPR) schemes (which are an essential part of the EU's ambition to create a circular economy) may also encourage ICT good producers to design products that have a longer lifespan and which are easier to recycle [b-EU Action], [ITU-T L.1021]. + +The European Commission recently informed about [b-EU SEP] a methodology [b-Bovea] that allows the analysis of how an existing product design meets design guidelines required for the circular-economy perspective, and which guidelines would need to be incorporated to create a better circular-design product. The results, based on a case study of small electrical equipment, indicate that the most urgent priority is to incorporate circular-design guidelines related to extending lifespan and to product/components reuse, while there is a moderate need to include guidelines related to the use of simple removable connections or a modular product structure. This methodology [b-Bovea] could be considered to be applied to different ICT goods. + +#### **7.1.4 JRC initiatives** + +Independently from CEN/CENELEC standardization work, the European Commission is in the process of analysing and developing a scoring system to rate the ability to repair and, where relevant, upgrade products. [b-JRC score]. + +The EC will not only rely on CENELEC TC10 but also on the work of the EC with JRC to develop proposals for goods group specific requirements to be considered under the ErP Regulation for smartphones, laptops and washing machines. JRC has already published reports on the durability assessment of goods, the analysis and testing of washing machines [b-JRC 2018] and understanding lifetimes and failure modes of defective washing machines and dishwashers [b-JRC 2019]. In 2019, JRC plans to finalize two draft studies published in April 2018 on the analysis of material efficiency aspects of smartphones and on the assessment of the reparability and upgradability of TVs. + +#### **7.1.5 ISO** + +ISO14009 aims to provide guidelines to organizations for managing redesign and redevelopment of their products in a systematic manner using the framework of environmental management system (EMS) [b-ISO14009]. + +#### **7.1.6 France** + +While the EU has an action plan focusing on certain products, France is introducing eparability labelling systems. France has launched a roadmap for the circular economy and they have the intention to develop a reparability index on all kinds of goods including the ICT sector. + +The reparability labelling system will cover a range of goods including smartphones. These reparability labels are expected to be published by 1 January 2021. The current draft of the method includes six criteria for smartphones, which themselves include sub-criteria: + +- **Criterion 1: availability of documentation with two sub-criteria:** + - availability and duration of availability (in years) + - user instructions, maintenance and product update information at the date of sale. +- **Criterion 2: accessibility, ease of disassembly and reassembly of unitary spare parts with 3 sub-criteria:** + - ease of disassembly and reassembly + - necessary tools + - fasteners. +- **Criterion 3: availability of spare parts with 4 sub-criteria:** + - undertaking for duration of availability of spare parts (in years) for key parts + - undertaking for duration of availability of spare parts (in years) for other parts + - undertaking for delivery time (in working days) for key parts + - undertaking for delivery time (in working days) for other parts. +- **Criterion 4: price of spare parts** calculated according to a ratio between the price of broken/malfunctioning parts and the price of new product. +- **Criterion 5: software** +- **Criterion 6: diagnostic** + +NOTE – The specified number of years, days and % will be decided by working groups established by the French authorities. + +### 7.2 Voluntary certification schemes + +#### 7.2.1 EPEAT in the US + +Labelling programmes in the US are non-mandatory (voluntary) certification schemes, but requirements might be included in the purchasing contracts. + +#### 7.2.2 SASF + +The sustainability assessment framework (SASF) is not a standard but a tool by which a company can evaluate the sustainability performance of its products. The scoring involves several CE related questions on product level [b-SASF]. + +#### 7.2.3 Modulated tariffs for e-waste treatment + +Currently, simplistic mass-based tariffs are common for financing the handling of e-waste, including ICT e-waste. However, differentiated fees for e-waste treatment can be expected in the coming years depending on product characteristics such as recyclability [b-EU WFD]. + +In 2018, the European Union amended its waste framework Directive to minimum requirements for extended producer responsibility schemes. One of the requirements is to modulate the financial contributions paid by the producer, where possible, for individual products or groups of similar products. The modulated fees shall take into account the durability, reparability, reusability and recyclability and the presence of hazardous substances. However, the fees shall not exceed the actual costs that are necessary to provide the waste management services in a cost-efficient way. The EU Member States have to transpose these requirements into national legislation by mid-2020, but the principle is already implemented in most countries. + +It is a common practice in the WEEE management sector to charge different prices for product categories that go into separate treatment processes (e.g., monitors and other ICT products). + +The ICT and CE industry in cooperation with WRAP has developed a logo to differentiate TVs and monitors at the treatment site depending on whether or not the backlights contain mercury [b-DIGITALEUROPE]. With this knowledge, modulated fees could be applied as mercury containing backlighting requires additional treatment steps and incur higher costs. + +However, most fee structures are still mass-based and do not reflect the actual recyclability of a product or product group. There is still need to develop relevant criteria limited to the targets of proper waste management and which are clearly defined to avoid ambiguity with other intentions or contradiction with other legislations [b-ERP]. + +## 8 Circular economy business models + +Business models are important for the success of the CE. This Recommendation will show some examples but the main aim is to focus on the applicability of existing CE metrics for ICT. The use of these business models do not immediately imply that the model is circular, but they improve the circularity compared to other business models depending on their design. + +New forms of business models drive the success of the CE. When companies transition from a product sales model to an as-a-service model, products remain in the possession of the manufacturer. Emphasis is placed on taking back the equipment at EoL. Product design is maximized for reoccurring value and the hardware life cycle and lifetime value is extended. + +The OECD published a paper in 2019, evaluating five *Business Models for the Circular Economy* [b-OECD]. The report covers circular supply models, resource recovery models, product life extension models, sharing models and product service system models. The OECD estimates that such business models currently have a market share of 5 to 10%. + +The philosophy of the circular supply model is that product materials are used for production of new product (cradle to cradle). Therefore, manufacturers need to design their products as well as adapt their processes with respect to this aim. + +The resource recovery model is based on three main activities to produce secondary raw materials from waste streams, that is, the collection, sorting and secondary production. + +The product lifetime extension model simply tries to keep products in the economy for a longer time and potentially reduce the extraction of new resources. This can be achieved by increasing the durability of goods, reuse and repair activities and remanufacturing. + +Examples of product lifetime extension models include: + +- sharing models which increase the usage of under-utilized consumer assets and therefore reduce the overall number of products that are required; +- user or result-oriented product service system (PSS) models where services rather than products are marketed, improve incentives for green product design and more efficient product use as products remain in the possession of the manufacturer. As emphasis is made on product service and reverse logistics, more sparing use of natural resources is promoted and lifetime is extended. + +However, product lifetime extension models always come with trade-offs. For example, energy savings and environmental impact reductions might not be achieved if older energy inefficient goods are used instead of newer more energy efficient goods. [b-ITU-T L.1410] can be used to find the balance points. + +Also the economical savings made by such models might be used instead for products or activities with a higher environmental impact. + +## **9 Circular economy aspects and parameters affecting the environmental impact in different life-cycle stages** + +The different aspects of the CE could be divided into different areas such as those proposed in this clause. There are different ways to carry out this subdivision into areas and they are to some extent overlapping. Subdivision can be done using, e.g., life-cycle stages, design stages, aspect sorting by name, or by expected quality. Here the CE aspects are sorted according to the first life-cycle stage where the environmental impacts are assumed to take place. + +It has to be differentiated between the environmental impacts ICT products cause during production (including material sourcing), its use stage and the treatment after the use stage. Different ICT products (e.g., mobile and stationary) might have different life-cycle stage focal points. + +Impacts not directly related to the product, but caused by organizational decisions which can lead to a reduction of the environmental impact, are covered in clause 10. + +The key question dealt with in clauses 9.1 to 9.4 is related to what extent different metrics are applicable to ICT. + +### **9.1 Raw material acquisition stage** + +#### **9.1.1 Recycled content** + +The recycled content indicator/metric as defined by ISO [b-ISO 14021] can be applied to ICT goods. However, reliable data might be difficult to collect due to long supply chains. Nonetheless, according to certain RC standards the manufacturer has to get written proof from upstream tiers that the materials used are secondary to the degree claimed. + +When looking at recycled content, one should be aware of the issues with substances of concern as discussed in clause 9.2.5. + +Specifically for metals, each material requires a different solution. For some, like rare earth elements, recycled material is not widely available. So simply understanding the barriers to recovery requires significant exploration. For other materials, such as tin, recycled material markets are more robust. + +#### **9.1.2 Renewable content** + +Renewable materials might be included in the RC calculations. + +The use of bamboo is becoming increasingly popular to make casings for computers and peripherals. It has the advantages of being a sustainable and quickly renewable resource [b-Kaur]. + +Renewable materials are not inherently sustainable, and must be correctly managed to ensure continued supply and avoid adverse impacts on humans or the environment. + +#### **9.1.3 Proportion of reused parts** + +The applicability of reused part standards is seemingly very high as the information can be controlled by the manufacturer. Certain reused part standards do not consider the reliability of the reused components. + +The quality of reused parts is very important. It is highly useful for the second-hand market if the quality of the parts, which can be removed from the used ICT goods or overproduced ICT goods, is "as good as new". The use of counterfeit parts, instead of original reused parts, is a problem for the reliability of the second-hand product. These parts can have the effect that the device is working poorly or cause electric shocks or fires. + +It is proven that laptops can be remanufactured successfully partly using reused parts. Defunct parts of laptops are replaced with functioning parts from others, and a new battery is added [b-Transform]. + +Pini et al. [b-Pini] studied the variations in environmental performance of the life cycles between new and reused EEE in Italy, including laptops. The scenarios feature preparation for reuse (repair and + +refurbish) using either new or reused replacement components. The results show that using new replacement components (for laptops) could lead to a worse environmental performance than the baseline (new product). + +André et al. [b-André] studied the environmental performance of using second-hand laptops facilitated by commercial reuse operations instead of using new ones. The new finding, apart from the finding that a use extension lowers environmental impacts, is that reuse companies steer non-reusable laptops into state-of-the-art recycling. + +#### 9.1.4 Use of critical raw materials + +Estimating CRM contents is relevant for ICT goods. + +CRMs selected by the EU can be found in [b-EUcrm]. Other jurisdictions might have other CRMs. + +CRMs may be substituted where possible. + +For smartphones the material amounts have been estimated for about 30 different metals including CRMs and rare-earth elements [b-L.ER]. Figure 1 shows the amounts of some common metals used in smartphones. + +![Bar chart titled 'Material content extract for a smartphone (in milligrams)' showing the amounts of various metals. The metals and their amounts are: Tungsten (242), Silver (225), Barium (184), Manganese (183), Tantalum (67), Gold (48), Titanium (44), Zirconium (35), Molybdenum (33), and Antimony (23).](8a597e344d10e36bbb2f243f6c4e74c6_img.jpg) + +| Material | Amount (mg) | +|------------|-------------| +| Tungsten | 242 | +| Silver | 225 | +| Barium | 184 | +| Manganese | 183 | +| Tantalum | 67 | +| Gold | 48 | +| Titanium | 44 | +| Zirconium | 35 | +| Molybdenum | 33 | +| Antimony | 23 | + +L.1022(19)\_F01 + +Bar chart titled 'Material content extract for a smartphone (in milligrams)' showing the amounts of various metals. The metals and their amounts are: Tungsten (242), Silver (225), Barium (184), Manganese (183), Tantalum (67), Gold (48), Titanium (44), Zirconium (35), Molybdenum (33), and Antimony (23). + +**Figure 1 – Extract of material content for a smartphone** + +Based on expert comments on Figure 1, the barium and manganese absolute content in smartphones might be significantly higher while the content of tantalum, titanium, molybdenum and antimony might be significantly lower. + +Recycling of CRMs are enhanced by: + +- 1) identifying the locations of the CRMs in the different sections of the ICT goods; +- 2) finding the different possible recycling paths for each material (with steel, copper or aluminium); +- 3) gathering the sections which could be recycled together; +- 4) suggesting a design for the ICT goods which optimizes the recovery of CRMs. + +#### 9.1.5 Materials of concern: Single-use plastics + +In recent years, SUP has become one of the most discussed sustainability issues. Retailers are starting to ban SUP and as a result the use is rapidly dwindling. [b-ITU-T L.1015] requires that *"The manufacturer shall indicate if a strategy to eliminate single-use plastic packaging is adopted."* + +ICT infrastructure products are not considered to be SUP products based on the extended period of use time, typically ten years, and multiple usage events during this use time. + +Some plastic packaging, which is protecting the products during storage and transportation, currently may be SUP. Such packaging could be avoided, e.g., by replacement, reuse, recycling, or recovery. + +The so-called oxo-plastics or oxo-degradable plastics are a type of SUP that are problematic from a CE perspective. They are conventional plastics which include additives to accelerate the fragmentation of the material into very small pieces, triggered by UV radiation or heat exposure. Due to these additives, the plastic will fragment over time into plastic particles, and finally microplastics. Full biodegradation process has not been documented for oxo-degradable plastics but rather that oxo-degradable plastic is not suited for long-term use, recycling or composting, and therefore not suitable for a circular economy [b-DG ENV], [b-bioplastics] and [b-Selke]. + +In order to biodegrade, typical biodegradable plastics [b-bioBag1] will need a high temperature environment for an extended period of time. Complicating things further, biodegradable plastics should be separated from traditional plastics waste in order to ensure high-quality plastic products. Plastic recyclers prefer that bio-based plastics [b-bioBag2] have their own collection scheme. Biodegradable plastics might biodegrade slower in landfills due to a lack of oxygen. Moreover, no product, including biodegradable plastics, has been approved as marine biodegradable [b-PlasticsR]. The European Standard EN 13432 [b-EN 13432] defines the characteristics that a compostable material must have. + +Telecommunication operators are requiring the elimination of SUP by 2020. + +### 9.2 Use stage + +#### 9.2.1 Durability + +The reliability part of durability is relevant for ICT goods. + +Durability might be the most important aspect seen from an environmental impact perspective for those ICT goods having a relatively large share of the life-cycle impacts caused by the manufacturing [b-ITU-T L.1015], [b-Andrae]. Increasing the lifespan of phones and improving collection after use will reduce pressures on non-renewable resources and close 'metal flow loops' [b-Sinha]. + +Reliability refers to a faultless period before the first failure. Durability on the other hand refers to a longer period which could involve repair and refurbish. Durability includes the ability of a product to be repaired. + +Durable design, especially of mobile ICT goods, includes the provision of software upgrades, patches and compatibility. Availability of such upgrades is important to extend the lifetime of the product. + +To ensure the availability of such upgrades, it is important that manufacturers provide sufficient customer service and support solutions. Another important factor is the development of a sufficient local infrastructure to enable the provision of maintenance services to the product users. + +There is always an upper limit of lifetime extension, beyond which the effects become net negative [b-Grobe]. + +##### *Including Drop resilience* + +Drop testing is typically conducted on products that are held in the hand during use. There are several standards available which describe drop test parameters. See, for example, [b-IEC 60068-2-31]. + +NOTE – [b-IEC 60068-2] is a collection of methods for environmental testing of electronic equipment in general. + +Durability testing for mobile ICT shall consist of both testing the components on their own and as a product. + +##### *Availability of customer service/support* + +The availability of proper instructions how to use an ICT product can increase their durability as users will be enabled to use the product properly and fix issues that otherwise might lead to disposal. The support can consist of proper instruction manuals delivered together with product or online, FAQs, support hotlines or websites or other means to support the user in properly using the product. + +For ICT infrastructure goods a maintenance service can help improve the durability. + +##### *Environmental and cost benefit rates* + +Environmental and cost benefit rates are generally useful for finding the maximum return on investment for a certain CE strategy [b-Huysman], [b-ArdenteR] and [b-ArdenteD]. + +However, the complications which arise when trying to define environmental benefit rate metrics for ICT concern mainly the precision of the underlying life cycle assessment (LCA) or life cycle cost (LCC) analysis. Nonetheless, with strict frameworks such as the product environmental footprint guide [b-PEF] and [b-ITU-T L.1410] the precision will be less of a problem. + +Appendix I of [b-ITU-T L.1015] presented three streamlined LCAs for smartphones by which the durability benefit rate can be calculated. + +The environmental cost for these LCAs were explored by Andrae [b-Andrae] concluding that, for a very specific smartphone case, the durability benefit rate at low collection rates is $\approx 75\%$ 1 for longevity and $\approx 11\%$ 2 for refurbish. + +Ardente et al. developed a method for assessing, from a life-cycle perspective, the potential environmental benefits of remanufacturing energy-related products [b-Ardente]. A specific enterprise server was chosen as example. + +#### **9.2.2 Energy efficiency** + +Use stage energy consumption is the biggest driver for the overall environmental impact for some of the ICT products, e.g., ICT infrastructure goods. For these products, energy efficiency is a very important product design criterion to minimize the harmful impact on the environment. Careful balancing is then needed to maximize both the material efficiency and energy efficiency of such products. + +#### **9.2.3 Reparability** + +High reparability normally requires a smart design for disassembly. CENELEC [b-prEN 45554] (working document version) regards disassembly as a condition to do the next step, making it a subcomponent of reparability. However, the ability to disassemble as such is not an end goal. Repair is also facilitated by the modular design of products. + +In order to assess a product's reparability, a prioritization of parts may take place because not all parts will be equally prone to be repaired. + +Therefore, not all parts need to be assessed, but only those that are more likely to fail during the expected lifetime of the product. These parts are called priority parts and is a central concept in [b-prEN 45554]. + +Product-related criteria included in [b-prEN 45554] are: + +- disassembly sequence and depth; +- fasteners used as well as tools; +- working environment and skill level required for a given repair. + +--- + +1 1-189/747. + +2 1-665/747. + +[b-prEN 45554] also suggests to consider support-related criteria when assessing a product's reparability and organization parameters which facilitate the replacement of priority parts. + +Support-related criteria include: + +- availability of information to consumers; +- repair flows; +- availability of spare parts, repair infrastructure and return models; +- repair instructions, exploded views available for authorized repair personnel. + +For mobile ICT goods, most common repair actions usually concern screens, batteries and charging ports. + +For ICT infrastructure equipment, it is less obvious to identify the most common repair actions or parts of the equipment that break down most frequently. + +While conceptional that reparability is a part of durability, there are trade-offs between reparability and reliability in the design of portable ICT goods such as smartphones. Many manufacturers prioritize design for reliability (e.g., water resistance, robustness) even though this could make it more difficult for common users to repair the product, for instance due to embedded batteries and use of adhesives instead of screws. It has also been reported that innovative adhesives such as pull tabs could make the repair of smartphones easier for professionals. + +The repair of ICT infrastructure equipment such as radio base stations, core routers, large networking equipment or data centre servers is done in an entirely different way than for ICT consumer goods. + +As ICT infrastructure goods are very costly and highly complex, they cannot be repaired by a local repair shop or non-dedicated, non-contracted repairers. + +These products very often make up a critical, highly available network infrastructure, thus no downtime can be permitted. To tackle this, service providers, financial institutions or data centre operators close service contracts where rapid support from the manufacturer is provided on software and hardware problems. In most cases, a product is immediately replaced by another when it breaks down. After the network is operational again, the failed product is sent back for analysis to a test facility in order to assess if and how it can be repaired. The product repair is done by dedicated specialized personnel which are trained by the manufacturer. Because the repairer is working under contract for the manufacturer, a close cooperation is guaranteed between both parties, often reoccurring issues and improvement suggestions are being fed-back to the engineering department of the manufacturer. Once repaired, the product is reintroduced to the market as spare parts again. + +Having these products repaired by a local independent repairer without contract and without close cooperation with the manufacturer is not advised because of issues with safety (high voltage/current), IPR and technical difficulties to repair. + +#### **9.2.4 Upgradeability** + +In order to assess a product's upgradeability, a prioritization of parts may take place because not all parts will be equally prone to be upgraded. The evaluation of parts for upgrade is expected to focus mainly, but not exclusively, on parts subject to rapid technological changes or changes in use profiles over the use phase of the product. [b-prEN 45554] suggests to consider product as well as support-related criteria when assessing a product's upgradeability. In cases where upgradability can only be achieved by replacing physical parts, product-related criteria may include the same product level criteria as for product reparability. However, specific attention should be given to the role of software and firmware. + +Upgradeability of the product can be assessed in terms of manufacturer support based on the availability of parts for upgrade (rather than spare parts). + +The upgradeability is also determined by the availability of supporting information and software and firmware support. + +##### *Software upgrade of ICT products* + +Software upgrades are commonly used for ICT products to increase and enhance their performance. Software upgrades improve the usable lifetime of ICT products. The interface for providing software upgrade is normally available in the ICT products and no disassembly is required for this. + +#### **9.2.5 Maintenance** + +Maintenance is commonly done in the ICT industry, especially for larger ICT infrastructure goods and software to increase the performance and lifespan of the goods. Maintenance can also be done remotely. + +Corrective maintenance is typically done as repair. + +Preventive maintenance is typically done to prevent total collapse of the ICT product. The maintenance includes periodic cleaning, inspection, etc. + +### **9.3 End-of-life stage** + +Collection of products at end of life is inevitable to achieve a circular economy and the participation of all actors is needed. In extended producer responsibility or product stewardship programmes, it is necessary that authorities, producers, distributors and consumers work together to achieve a high quality and volume of collected waste. + +Where no mandatory programmes exist, it is key to provide incentives to users to return products to a system where they can be reused, refurbished or recycled. Such programmes need to be easy to access and visible to the product user. Therefore efforts have to be taken to raise awareness for these voluntary programmes. + +#### **9.3.1 Reusability** + +To assess and increase the ability to reuse products, a range of criteria has to be considered. Reuse can apply to either a whole product or to parts of it. The ability to reuse a product is interconnected to its durability, the ability to repair it and the ability to upgrade it. + +Whereas the ability to reuse parts of it is also interconnected to the ability to disassembly it to harvest the reusable parts. + +In some product (groups) and this is especially important for mobile ICT goods, the ability to reuse them is determined by the ability to transfer and permanently delete (personal) data from it. + +Ease of data erasure is important, especially for mobile ICT to encourage users to hand used products over to another user. + +On this topic, there is occasionally a trade-off between the security of users' personal information, protected by a personal code allowing complete wipe-out, and the willingness of refurbishing companies to lock up older but well-functioning products, perform complete wipe-out and refurbish for a new life. + +#### **9.3.2 Recyclability** + +Crucial for high recyclability rates is ease of disassembly into recyclable streams (unless contradicting safety requirements). + +[b-prEN 45555] can be used to estimate the recyclability. + +The actual recyclability rate is always related to the available technology. + +#### 9.3.3 Reused components + +It might be important to be able to reclaim components for reuse. Manufacturers shall strive to reuse components/parts/materials at the end-of-life stage. + +[b-prEN 45556] provides four calculation methods for assessing the proportion of reused components in an energy-related product based on the mass and the number of reused components. + +#### 9.3.4 Remanufacture ability/refurbish ability + +[b-prEN 45553] identifies seven general process steps which are considered to be crucial for the remanufacturing and refurbishment. Product-specific standards can be developed based on these steps. The steps are: + +- inspection +- disassembly +- cleaning +- reprocessing +- reassembly +- testing +- storage. + +The ability to disassemble is important for the ability to remanufacture. + +#### 9.3.5 Substances of concern + +Occasionally there is a conflict between waste, chemicals and products. Laws might change which prevents recycling. New products cannot be placed on the market when using recycled components that include banned substances. + +Examples are Cd in batteries and PVC cables [b-Friege]. + +The incineration of plastics usually emit hazardous substances but might help avoid CO2 emissions by replacing electric power production. The recycling of plastic usually helps avoid CO2 emissions but might keep harmful substances in the loop. + +It should be analysed which substances, used in the ICT supply chains, are regulated in which parts of the world, and how that affects the recyclability and reusability. + +Recycling and reuse can be hampered by the presence of certain chemicals. Some chemicals can simply constitute technical barriers preventing recycling. Even a benign substance, which for example has a strong smell, could in some cases prevent use of the recycled material. Other chemicals are hazardous to humans or the environment. A growing number of these are being identified and becoming subject to restrictions or prohibitions. These chemicals may be present in products sold before the restrictions applied, some of which have a long lifetime, and therefore prohibited chemicals can sometimes be found in recycling streams. Such substances can be costly to detect or remove, creating obstacles in particular for small recyclers. All these different types of chemicals are known as 'substances of concern' for the purpose of this Recommendation [b-EUCOM32]. + +## 10 Circular economy on an organizational level + +Decisions taken at an organizational level have an impact on the circularity of ICT products beyond their design. For example, striving to improve the quality of recycling can lead to better material quality and a larger share of recycled content in future products, not only for the manufacturer, but also for the whole ICT industry. + +Companies can organize their reverse logistics in several ways to improve CE, such as: + +- provide product return pickup and transport at no cost for any customer worldwide upon request; +- establish alternative commercial models that promote product return, including, purchase trade-in, banked credit, leasing, and product-as-a-service; +- offer comprehensive warranty, replacement, service and repair for all products to extend useful product lifetime and minimize obsolescence; +- repurpose returned product, subsystems, components and commodities, including closed-loop return to new product manufacturing. + +Two metrics that have been used on corporate level are: + +- 1) reuse rate of returned products; +- 2) landfill share of globally handled scrapped materials [b-Huawei]. + +### **10.1 Reduction and reuse of production scrap** + +Waste generated during the manufacturing process should be reduced, reused, recycled, composted, or when necessary converted to energy according to the waste hierarchy. The final target should be a zero waste to landfill policy. If production scrap cannot be avoided, it shall be reused where possible or otherwise utilized for maximum environmental benefit. + +### **10.2 Operating with renewable energy** + +Besides reducing the total energy use and increasing the efficiency of ICT products, the operation of manufacturing and other facilities with renewable energy is an important step to achieve circular economy at an organizational level. This can be achieved through direct use of renewable energy by building own energy infrastructure or purchasing renewable energy from suppliers or by procuring renewable energy credits. + +### **10.3 Transportation** + +The transportation of products, supplies and employees is contributing a fair share to emissions of greenhouse gases and nitrogen oxides. This can be reduced by shifting to renewable fuels, enabling telecommuting and videoconferencing, supporting the use of public transport or instalment of company commuting programmes. + +### **10.4 Reduction of water usage** + +Water is used in different processes in the ICT industry, e.g., for cooling, sanitation, landscaping or during production. + +In general, it should be the target to reduce water usage, but besides that there are alternatives such as the reduction of freshwater use by using recycled water and harvesting rainwater. + +Special emphasis should be placed on facilities in water stressed regions and suppliers of components that are identified to have a high water usage. + +### **10.5 IoT enabled circularity** + +Enhanced material recovery and reuse could be facilitated by advanced sorting, robotic disassembly, and digital tracing. Moreover, 3D printing will reduce the need for large manufacturing and might reduce waste and VR will reduce maintenance time and keep products in use longer. Additionally, blockchain can help transform the life cycle inventory (LCI) and traceability in the materials handling. Also, dark factories can save electricity used by lighting and air conditioning [b-Huawei]. + +### **10.6 Studies examining monitoring and control services with sensors and ICT infrastructure focused on waste management** + +Lelah et al. investigated a machine-to-machine enhanced product service system for the collection of waste glass, in which the collection routes were planned on the basis of real-time data on collection containers' degree of fill [b-Lelah]. + +Bonvoisin et al. made an LCA of a municipal waste collection system based on a city-scale wireless sensor network [b-Bonvoisin]. + +### **10.7 Take-back models reverse return logistics** + +Closed-loop efforts can: + +- provide product return pickup and transport at no cost for any customer worldwide upon request; +- establish alternative commercial models that promote product return, including, purchase trade-in, banked credit, leasing and product-as-a-service; +- offer comprehensive warranty, replacement, service and repair for all products to extend useful product lifetime and minimize obsolescence; +- repurpose returned product, subsystems, components and commodities, including, closed-loop return to new product manufacturing. +- establish a dedicated circular economy performance indicator tracking appropriate progress. + +### **10.8 AI enabled circularity** + +Artificial intelligence (AI) can play an important role in the shift from a linear to a circular economy because AI allows us to deal effectively with complexity and make sense of abundant data. + +AI can enhance and enable circular economy innovation across industries [b-EllenAICE] in three main ways: + +1. Design circular products, components, and materials. AI can enhance and accelerate the development of new products, components, and materials fit for a circular economy through iterative machine-learning-assisted design processes that allow for rapid prototyping and testing. +2. Operate circular business models. AI can magnify the competitive strength of circular economy business models, such as product-as-a-service and leasing. By combining real-time and historical data from products and users, AI can help increase product circulation and asset utilization through pricing and demand prediction, predictive maintenance, and smart inventory management. +3. Optimize circular infrastructure. AI can help build and improve the reverse logistics infrastructure required to 'close the loop' on products and materials by improving the processes to sort and disassemble products, remanufacture components and recycle materials. + +### **10.9 Wider system considerations** + +Several cases exist in which ICT goods are repurposed to be used as something other than the original product. A recent lifetime extension approach includes repurposing notebook computers to thin client computers [b-Coughlan]. Another is the repurposing of a smartphone into an in-car parking meter or a portable solar charger [b-Zink]. It has also been proposed to repurpose electric vehicle Li-ion batteries for energy storage in a second-use application such as buildings [b-Bobba]. + +### 10.10 Circular economy in new network equipment acquisition process + +One telecommunication operator has reported their example case of how to enquire about topics such as reparability, recyclability or upgradability when purchasing new equipment (b-CARE). + +Circularity evaluation methods have been developed these last years (e.g., circular economy toolkit [b-Tool] or material circular indicator [b-Ellen]) but they are ill-suited for a telecommunication operator. Indeed, some of them are based on questions requesting very precise knowledge on the equipment architecture, with questions such as "Is there a complete bill of materials and substances for the product?" Others do not provide the level of granularity required (failure rate is defined with levels as "Product failures rarely occur" or "Product failures are frequent"). + +Therefore, the main goal of the method developed for the example case at hand is to use the same key criteria (durability, reparability, etc.) as in the CEN/CENELEC JTC 10 documents but with tailored questions for each type of equipment. The first trials covered six criteria: + +- **Durability**, with questions about the three most critical failure modes at equipment level according to FMEA and MTBF assessment at equipment level; +- **Reparability**, with, for example, a question regarding the type of fasteners used on electronic boards. Heatsinks fastened with acrylic thermal conductive adhesive which might damage the board or the integrated circuit's integrated heat spreader (IHS) during disassembly process); +- **Upgradability**, with for example a question regarding the ability to upgrade the equipment critical components (e.g., CPU, HDD/SSD and RAM for a server); +- **Refurbish ability**, with for example a question regarding time required to swap field-serviceable components; +- **Recycled content**, with for example a question regarding the post-consumer recycled material intentionally used for large metal parts (e.g., heatsinks or cabinet); +- **Critical raw materials (CRM) content**, with for example a question regarding the manufacturer's ability to provide information on CRM content (the 2017 EU Critical Raw Materials list is used as a reference [b-EU]). + +For each question covered in the different criteria, several levels of performance were defined. For instance, fasteners can be categorized as reusable, non-reusable but which can be removed without any damage or problematic residue on the electronic board or non-removable. + +For each criterion (e.g., reparability) a weighted importance is applied. + +## 11 Reporting + +[b-EN 45559] provides a common method for the provision of information related to the material efficiency aspects of ErP. + +The content and the way of providing information related to material efficiency depends on several aspects and can diverge according to the intended target audience and sensitivity of the data. + +[b-EN 45559] mentions several topics related to material efficiency: + +- durability +- ability to remanufacture +- ability to repair, reuse and upgrade +- recyclability and recoverability +- proportion of reused components +- proportion of recycled content +- use of critical raw material. + +However, information could also be provided on other topics, such as the use of conflict minerals according to guidelines provided by the OECD [b-OECDcon] or the use of certified paper products. Conflict minerals reporting is related to using only minerals that do not directly or indirectly finance armed conflict or benefit armed groups. Conflict minerals are understood to be gold, coltan (columbite-tantalite), cassiterite, wolframite, tantalum, tin and tungsten. + +The use of paper is widespread in the ICT industry for packaging and providing information to users (instruction manuals, warranty documents, etc.). Using recycled paper content and sourcing virgin fibres only from sustainably managed forests or controlled wood sources is an important step to improve the circularity of paper products. + +The reported content can have a qualitative or a quantitative nature depending on the type of information and intended audience. + +The intended audience can be divided into: + +- end users (professional and/or private persons); +- professionals (in product-related services such as retail, repair, maintenance, recycler); +- market surveillance authorities. + +Depending on the sensitivity of the data, the disclosure of information might be limited to a restricted audience or made available to the public. The manufacturer shall decide which data is considered to be confidential, except when provision is mandated by the legislator. + +The means of communication shall be chosen according to the intended user, the type and amount of information to be provided and the needed duration of availability. + +Information could, for example, be provided on or with the product or its packaging, online, or at the point of sale. + +## 12 Insights and conclusions + +The following insights and conclusions can be drawn in this Recommendation: + +- The material efficiency field is characterized by initiatives by several actors beyond M543. +- A vast number of companies have already implemented smart circularity solutions and business models, as well as having quantified the benefits. +- Designing ICT products for circularity always includes weighing different, sometimes contradicting targets such as durability, robustness and ability to repair and recycle goods. The ability to repair is important for the circularity of products, but due to the complexity of ICT products, it can be necessary that the repair is conducted by professionals authorized and trained by the manufacturer. Software and firmware are integral parts of ICT goods and need to be taken into account when designing and maintaining them. Another important factor is the availability of proper information and support by the manufacturer for the customer using the goods. +- For large and complex ICT infrastructure equipment, it is challenging to identify most common repair actions or parts of the equipment that break down most frequently. +- For large and complex ICT infrastructure equipment, it does not make sense to do local repair by non-professionals. Nevertheless, fibre optic cables may be repaired by non-professionals. +- For gateways, leasing business models works very well. +- Recycled content of CRM in ICT goods cannot be quantified easily. +- It is important to consider the circularity application while balancing between the environmental and business model perspectives. + +## Bibliography + +- [b-ITU-T L.1015] Recommendation ITU-T L.1015 (2019), *Criteria for evaluation of the environmental impact of mobile phones*. +- [b-ITU-T L-Sup.5] ITU-T L-series Recommendations - Supplement 5 (2014), *Life-cycle management of ICT goods*. + +- [b-ITU-T L-Sup.28] ITU-T L-series Recommendations – Supplement 28 (2017), *Circular economy in information and communication technology; definition of approaches, concepts and metrics*. + +- [b-Andrae] Andrae, A.S.G. *Collection rate and reliability are the main sustainability determinants of current fast-paced, small, and short-lived ICT products*. 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New York, NY: United Nations. 306 pp. Available [viewed 2018-11/15] at: +[https://unstats.un.org/unsd/publication/seriesm/seriesm\\_4rev4e.pdf](https://unstats.un.org/unsd/publication/seriesm/seriesm_4rev4e.pdf) +- [b-ISO 14009] ISO14009 (2018), *Guidelines for incorporating redesign of products and components to improve material circulation*. + +- [b-ISO 14021] ISO 14021 (2016), *Preview Environmental labels and declarations – Self declared environmental claims (Type II environmental labelling)*. +- [b-JRC 2018] +- [b-JRC 2019] +- [b-JRC score] *Analysis and development of a scoring system for repair and upgrade of products*. +, doi: 10.2760/725068. +- [b-Kaur] Kaur, K., Gupta, M., & Kaul, A. (2018), *Green Computing: An Ecofriendly Approach to Manage E-waste*. + +- [b-L.1410] *Methodology for the assessment of the environmental impact of information and communication technology goods, networks and services*. + +- [b-L.ER] C-0485 Geneva, (2019), *Contribution SG5 on materials content in mobile phones for ITU-T L.ER Guidelines and Certification schemes for e-Waste Recyclers*. +- [b-Lelah] Lelah, A., Mathieux, F., Brissaud, D. (2011), *Contributions to eco-design of machine-to-machine product service systems: the example of waste glass collection*. J. Clean. Prod. 19, 1033–1044. + +- [b-M543] M/543 Commission Implementing Decision (2015) 9096 of 17.12.2015 on a standardization request to the European standardization organizations as regards ecodesign requirements on material efficiency aspects for energy-related products in support of the implementation of Directive 2009/125/EC of the European Parliament and of the Council. +[http://ec.europa.eu/growth/toolsdatabases/mandates/index.cfm?fuseaction=search\\_detail&id=564](http://ec.europa.eu/growth/toolsdatabases/mandates/index.cfm?fuseaction=search_detail&id=564) +- [b-NF] NF C18-510, +- [b-Nissen] Dimitrova, Gergana; Nissen, Nils; Stobbe, Lutz; Schlösser, Alexander; Schischke, Karsten; Lang, Klaus-Dieter (2014), *Tablet PCs through the* + +- lens of environment – Design trends and impacts on the environmental performance.* [http://publica.fraunhofer.de/eprints/urn\\_nbn\\_de\\_0011-n-3159392.pdf](http://publica.fraunhofer.de/eprints/urn_nbn_de_0011-n-3159392.pdf) +- [b-OECD] *Business Models for the Circular Economy – Opportunities and Challenges for Policy.* +- [b-OECDcon] *Guidance for Responsible supply Chains of Minerals from Conflict-Affected and High-Risk Areas.* +- [b-PAS 141:2011] *Reuse of used and waste electrical and electronic equipment (UEEE and WEEE). Process management. Specification.* +- [b-PEF] European Commission. *Environmental Footprint Guidance document – Guidance for the development of Product Environmental Footprint Category Rules (PEFCRs), version 6.3, December 2017.* [http://ec.europa.eu/environment/eussd/smfp/pdf/Guidance\\_products.pdf](http://ec.europa.eu/environment/eussd/smfp/pdf/Guidance_products.pdf) +- [b-Pini] Pini M, Lolli F, Balugani E, Gamberini R, Neri P, Rimini B, Ferrari AM, *Preparation for reuse activity of waste electrical and electronic equipment: Environmental performance, cost externality and job creation*, Journal of Cleaner Production (2019), doi: +- [b-PlasticsR] +- [b-prEN 45552] Draft prEN 45552. ICS 13.020.20, (2018), *General method for the assessment of the durability of energy related products CEN-CLC/JTC10.* +- [b-prEN 45553] Draft prEN 45553. ICS 13.030.50, (2018), *General method for the assessment of the ability to remanufacture energy related products in CEN-CLC/JTC10.* +- [b-prEN 45554] Draft prEN 45554. ICS 13.030.50, (2018), *General methods for the assessment of the ability to repair, reuse and upgrade energy related products CEN-CLC/JTC10.* +- [b-prEN 45555] CEN-CLC JTC10, (2018), 04 EN 45555 (2019), *Secretariat: The Netherlands General methods for assessing the recyclability and recoverability of energy-related products.* +- [b-prEN 45556] *General method for assessing the proportion of re-used components in energy-related products; German and English version prEN 45556 (2018).* +- [b-prEN 45557] NEN-EN 45557 (2018), Ontw. en. *General method for assessing the proportion of recycled material content in energy related products.* +- [b-REACH] Regulation (EC) No 1907/2006 of the European Parliament and of the Council of 18 December 2006 concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH). +- [b-SASF] Sustainability Assessment Framework (SASF). +- [b-Schischke] Schischke, Karsten; Stobbe, Lutz; Dimitrova, Gergana; Scheiber, Sascha; Oerter, Markus; Nowak, Torsten; Schlösser, Alexander; Riedel, Hannes; Nissen, Nils F. (2014), *Disassembly analysis of slates: Design for repair* + +and recycling evaluation. Final report. + +[http://publica.fraunhofer.de/eprints/urn\\_nbn\\_de\\_0011-n-2986729.pdf](http://publica.fraunhofer.de/eprints/urn_nbn_de_0011-n-2986729.pdf) + +- [b-Selke] Selke, S.; Auras, R.; Nguyen, T.A.; Castro Aguirre, E.; Cheruvathur, R.; Liu, Y. (2015), *Evaluation of Biodegradation-Promoting Additives for Plastics*. +- [b-Sinha] Sinha, R., Laurenti, R., Singh, J., Malmström, M.E. & Frostell, B. (2016), *Identifying ways of closing the metal flow loop in the global mobile phone product system: A system dynamics modeling approach*. *Resources, Conservation and Recycling*. 113: 65–76. [https://www.researchgate.net/publication/304525452\\_Identifying\\_ways\\_of\\_closing\\_the\\_metal\\_flow\\_loop\\_in\\_the\\_global\\_mobile\\_phone\\_product\\_system\\_A\\_system\\_dynamics\\_modeling\\_approach](https://www.researchgate.net/publication/304525452_Identifying_ways_of_closing_the_metal_flow_loop_in_the_global_mobile_phone_product_system_A_system_dynamics_modeling_approach) +- [b-Talens] Talens Peiró, L., Ardente, F., & Mathieux, F. (2017), *Design for Disassembly Criteria in EU Product Policies for a More Circular Economy: A Method for Analyzing Battery Packs in PC-Tablets and Subnotebooks*. *Journal of Industrial Ecology*, 21(3), 731-741. +- [b-Thomas] Thomas, B. (2015), *Earned green value: A conceptual framework to measure sustainability in projects based on the earned value methodology*. [https://www.researchgate.net/profile/Benjamin\\_Koke/publication/304830945\\_Earned\\_Green\\_Value\\_A\\_Conceptual\\_Framework\\_to\\_measure\\_Sustainability\\_in\\_Projects\\_based\\_on\\_the\\_Earned\\_Value\\_methodology/links/577c1cf408ae355e74f16af6.pdf](https://www.researchgate.net/profile/Benjamin_Koke/publication/304830945_Earned_Green_Value_A_Conceptual_Framework_to_measure_Sustainability_in_Projects_based_on_the_Earned_Value_methodology/links/577c1cf408ae355e74f16af6.pdf) +- [b-Tool] Access: +- [b-Transform] Transform together: Case studies: *Sustainable solutions for transforming the smartphones and ICT sector*. *Circular Computing: giving laptops a new lease of life*. [https://transform-together.weebly.com/uploads/7/9/7/3/79737982/transform\\_together\\_case\\_studies\\_circular\\_computing\\_feb\\_2019.pdf](https://transform-together.weebly.com/uploads/7/9/7/3/79737982/transform_together_case_studies_circular_computing_feb_2019.pdf) +- [b-Trusty] Trusty, W., Horst, S.: *Integrating LCA Tools in Green Building Rating Systems*. +- [b-Vanegas] Paul Vanegas, Jef R. Peeters, Dirk Cattrysse, Paolo Teechio, Fulvio Ardente, Fabrice Mathieux, Wim Dewulf, Joost R. Duflou (2018), *Ease of disassembly of products to support circular economy strategies – Resources, Conservation and Recycling*, Volume 135, August 2018, Pages 323-334. +- [b-VDI 2343] Guideline, Electronic Scrap, Recommendation. +- [b-WEEE] *Directive 2012/19/EU of the European Parliament and of the Council of 4 July 2012 on waste electrical and electronic equipment (WEEE)*. +- [b-Zink] Zink, T., Maker, F., Geyer, R., Amirtharajah, R., & Akella, V. (2014), *Comparative life cycle assessment of smartphone reuse: repurposing vs. refurbishment*. *The International Journal of Life Cycle Assessment*, 19(5), 1099-1109. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1024-202101-I_PDF-E/71ab4df17511d75261da8d462d643b1a_img.jpg b/marked/L/T-REC-L.1024-202101-I_PDF-E/71ab4df17511d75261da8d462d643b1a_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..7f4bd566b8a2d6ce4a3ab6c63366458f6b3fb456 --- /dev/null +++ b/marked/L/T-REC-L.1024-202101-I_PDF-E/71ab4df17511d75261da8d462d643b1a_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:5c58aa4e2a2d0f331fdd10ed019e79febdaa8f4473b4d1f38e6e7945ac54d54a +size 130444 diff --git a/marked/L/T-REC-L.1024-202101-I_PDF-E/98ee20ceb85cd84e2415b20b1eda1bcf_img.jpg b/marked/L/T-REC-L.1024-202101-I_PDF-E/98ee20ceb85cd84e2415b20b1eda1bcf_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..1cd4d75732e345bc77cef894735044ac3cdb9eec --- /dev/null +++ b/marked/L/T-REC-L.1024-202101-I_PDF-E/98ee20ceb85cd84e2415b20b1eda1bcf_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:2a43f9933430513dbfe7015eaf986398bd073ba0d6ffc6039fc91abcdb4cd0f7 +size 42856 diff --git a/marked/L/T-REC-L.1024-202101-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg b/marked/L/T-REC-L.1024-202101-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..1d8deae6031c18707104a329a7eae044811bbb4b --- /dev/null +++ b/marked/L/T-REC-L.1024-202101-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:f418e2fcf77b057e807e60d0a0a741dd98ab9ee337764072def10cd9ce79d647 +size 5986 diff --git a/marked/L/T-REC-L.1024-202101-I_PDF-E/af7916c89a458fdab6c3f443217388ae_img.jpg b/marked/L/T-REC-L.1024-202101-I_PDF-E/af7916c89a458fdab6c3f443217388ae_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..fd7e48eb3f1592719ee0ff7aa986ac096006ea7e --- /dev/null +++ b/marked/L/T-REC-L.1024-202101-I_PDF-E/af7916c89a458fdab6c3f443217388ae_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:20faf033f8b4f8c275bddaba19da9fe6ba3ae2c3921b7da002407eb65a0c5637 +size 60100 diff --git a/marked/L/T-REC-L.1024-202101-I_PDF-E/b05fbb6a015ea153c1e25245772b1a1b_img.jpg b/marked/L/T-REC-L.1024-202101-I_PDF-E/b05fbb6a015ea153c1e25245772b1a1b_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..7ea7a6b2bbc5845f35f573a43c9e20f0a6e3ab24 --- /dev/null +++ b/marked/L/T-REC-L.1024-202101-I_PDF-E/b05fbb6a015ea153c1e25245772b1a1b_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:2bf8d702120edef5d9005a4272cde8944d34a6d369bf1fff831bcc8979d0919b +size 115683 diff --git a/marked/L/T-REC-L.1024-202101-I_PDF-E/d4af765160d04ecef538e5066006dc77_img.jpg b/marked/L/T-REC-L.1024-202101-I_PDF-E/d4af765160d04ecef538e5066006dc77_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..83f0daa2bb19d1055da14e8ac1bcbaa5192e7bab --- /dev/null +++ b/marked/L/T-REC-L.1024-202101-I_PDF-E/d4af765160d04ecef538e5066006dc77_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:67bb5e6068901b464e808b08890bdc75f96019956fb97e74a270ea723b57b61d +size 25650 diff --git a/marked/L/T-REC-L.1024-202101-I_PDF-E/raw.md b/marked/L/T-REC-L.1024-202101-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..c915e24cb1f7f84afbc1bc915f8349ea09f71d55 --- /dev/null +++ b/marked/L/T-REC-L.1024-202101-I_PDF-E/raw.md @@ -0,0 +1,1015 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.1024** + +(01/2021) + +SERIES L: ENVIRONMENT AND ICTS, CLIMATE +CHANGE, E-WASTE, ENERGY EFFICIENCY; +CONSTRUCTION, INSTALLATION AND PROTECTION +OF CABLES AND OTHER ELEMENTS OF OUTSIDE +PLANT + +--- + +**The potential impact of selling services instead +of equipment on waste creation and the +environment – Effects on global information and +communication technology** + +Recommendation ITU-T L.1024 + +# ITU-T L-SERIES RECOMMENDATIONS + +## **ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT** + +## **OPTICAL FIBRE CABLES** + +| | | +|-------------------------------------|-------------| +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | + +### **OPTICAL INFRASTRUCTURES** + +| | | +|--------------------------------------------------------|-------------| +| Infrastructure including node elements (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | + +## **MAINTENANCE AND OPERATION** + +| | | +|-------------------------------------------------|-------------| +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | + +## **PASSIVE OPTICAL DEVICES** + +| | | +|-------------------------|-------------| +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +|-------------------------|-------------| + +## **MARINIZED TERRESTRIAL CABLES** + +| | | +|------------------------------|-------------| +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | +|------------------------------|-------------| + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1024 + +## The potential impact of selling services instead of equipment on waste creation and the environment – Effects on global information and communication technology + +## Summary + +Recommendation ITU-T L.1024 utilizes information compiled from stakeholders that provides insights into cases in the information and communication technology (ICT) ecosystem, in which ICT goods are sold as services or subscriptions rather than products. Currently, these cases are not clearly understood from an environmental point of view. + +Current estimates are that billions of new ICT goods – smartphones and others – are sold annually and sales are expected to be higher in 2025 than in 2020. + +Business models based on servitization which would – most effectively – improve the circularity of these ICT goods are not well understood, e.g., prolonging the lifetime or increasing the e-waste collection rate. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.1024 | 2021-01-06 | 5 | 11.1002/1000/14564 | + +## Keywords + +Business model, circular economy, environmental footprint, refurbishment, remanufacturing, repair, reuse, servitization. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2021 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|---------------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 2 | +| 3.1 Terms defined elsewhere ..... | 2 | +| 3.2 Terms defined in this Recommendation..... | 2 | +| 4 Abbreviations and acronyms ..... | 3 | +| 5 Conventions ..... | 3 | +| 6 Business models ..... | 3 | +| 6.1 Desktop computing as a service per hour via different business models ..... | 4 | +| 6.2 Practical approach showing SEEQ business model ..... | 5 | +| 7 Analytical approaches..... | 11 | +| 7.1 Remanufacturing trade-off for enterprise server ..... | 11 | +| 7.2 Refurbish trade-off for smartphone ..... | 12 | +| 7.3 Set-top box refurbish trade-offs..... | 13 | +| 7.4 Desktop box refurbish trade-offs..... | 14 | +| 7.5 Optical network terminal refurbish trade-offs..... | 15 | +| 7.6 Base station remanufacturing trade-offs..... | 15 | +| 8 Global change effect of servitization of desktops, laptops and gateways ..... | 16 | +| 8.1 Desktops ..... | 16 | +| 8.2 Laptops ..... | 18 | +| 8.3 Modems (Wi-Fi)..... | 19 | +| 9 Discussion..... | 20 | +| Bibliography..... | 22 | + + + +# Recommendation ITU-T L.1024 + +## The potential impact of selling services instead of equipment on waste creation and the environment – Effects on global information and communication technology + +# 1 Scope + +This Recommendation contains analyses and predictions of the real or potential environmental consequences of a transfer to selling services instead of equipment for the global information and communication technology (ICT) industry. + +It is plausible that some economic realities will drive some parts of the ICT ecosystem to be sold as services instead of goods. There are several studies looking at parts of the ecosystem and specific service transformations. However, there are few studies focusing on what this likely trend will mean for overall environmental impact. + +The Recommendation considers possible conflicts and solutions regarding the opportunities and problems arising from a potential global service transformation of ICT. + +The Recommendation contains a guide to cases where a service transformation makes sense or not from an environmental point of view. + +This Recommendation takes into account previous and ongoing appropriate ITU deliverables on life cycle assessment (LCA) and circular economy, e.g., [b-ITU-T L.Supp1.28], [ITU-T L.1015], [ITU-T L.1020], [ITU-T L.1021], [ITU-T L.1022] and [ITU-T L.1023]. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T L.1015] Recommendation ITU-T L.1015 (2019), *Criteria for evaluation of the environmental impact of mobile phones*. +- [ITU-T L.1020] Recommendation ITU-T L.1020 (2018), *Circular economy: Guide for operators and suppliers on approaches to migrate towards circular ICT goods and networks*. +- [ITU-T L.1021] Recommendation ITU-T L.1021 (2018), *Extended producer responsibility – Guidelines for sustainable e-waste management*. +- [ITU-T L.1022] Recommendation ITU-T L.1022 (2019), *Circular economy: Definitions and concepts for material efficiency for information and communication technology*. +- [ITU-T L.1023] Recommendation ITU-T L.1023 (2020), *Assessment method for circular scoring*. +- [ITU-T L.1410] Recommendation ITU-T L.1410 (2014), *Methodology for environmental life cycle assessments of information and communication technology goods, networks and services*. + +# 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 global warming potential (GWP)** [ITU-T L.1410]: Ratio of the warming of the atmosphere caused by one greenhouse gas to that caused by a similar mass of carbon dioxide. GWP is calculated over a specific time frame generally 100 years. + +NOTE – See also [b-ITU-T L.Supp1.32]. + +**3.1.2 preparing for reuse** [b-Ardente]: Checking, cleaning or repairing recovery operations, by which products or components of products that have become waste are prepared so that they can be reused. + +**3.1.3 reconditioning; refurbishing** [b-Ardente]: Return a used product to a satisfactory working condition by rebuilding or repairing major components that are close to failure, even where there are no reported or apparent faults in those components. + +**3.1.4 remanufacturing** [b-Ardente]: Return a used product [or component] to at least its original performance with a warranty that is equivalent or better than that of the newly manufactured product. + +**3.1.5 repurposing** [b-Ardente]: Utilize a product or its components in a role that it was not originally designed to perform. + +**3.1.6 reuse** [b-EN 45554]: Process by which a product or its parts, having reached the end of their first use, are used for the same purpose for which they were conceived. + +**3.1.7 second-hand product** [b-Ardente]: Tangible movable property that is suitable for further use as it is or after repair. + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 abiotic resource depletion potential (ADP)**: From a functional point of view, is the decrease of availability of the total reserve of potential functions of resources. From the intrinsic value of naturally occurring minerals point of view, is the decrease of the unique natural configurations of elements in resources in the environment. Abiotic refers to natural resources (including energy resources) such as iron ore, crude oil which are regarded as non-living. + +NOTE – Paraphrased from [b-van Oers]. See also [b-ITU-T L.Supp1.32]. + +**3.2.2 computational use value**: A rating of the usefulness of a computing device for specific computing tasks + +**3.2.3 cumulative energy demand (CED)**: A measure of primary energy demand from renewable and non-renewable resources or similar that can be used as representative of primary energy consumption. + +NOTE – See [ITU-T L.1410]. + +**3.2.4 energy proportional computing**: Energy proportionality is a measure of the relationship between power consumed in a computer system, and the rate at which useful work is done (its utilization, which is one measure of performance). If the overall power consumption is proportional to the computer's utilization, then the machine is said to be energy proportional. + +NOTE – Based on [b-Barroso]. + +**3.2.5 recycling use value**: A rating of the value of a computing device based on raw material value considering the cost of recycling it. + +**3.2.6 re-use rate:** Degree to which an information and communication technology (ICT) good or its component parts are reused for the same purpose. + +**3.2.7 servitization:** The process of creating value by adding services to products. In more detail 'the offering in terms of "goods or services" through "goods and services" to the marketing of bundles of "goods + services + support + knowledge + self-service".' + +NOTE – See [b-Kowalkowski]. + +**3.2.8 use value:** A rating of the usefulness of a good for a useful purpose, in comparison to the exchange value by which the commodity compares an item to other objects on the market. + +NOTE – Based on [b-Franquesa 2018]. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|--------|-----------------------------------------------------| +| ADP | Abiotic resource Depletion Potential | +| CED | Cumulative Energy Demand | +| ED | Energy Depletion | +| GWP | Global Warming Potential | +| GWP100 | Global Warming Potential at 100 years | +| HDD | Hard Disc Drive | +| ICT | Information and Communication Technology | +| LCA | Life Cycle Assessment | +| ONT | Optical Network Terminal | +| PCB | Printed Circuit Board | +| PCBA | Printed Circuit Board Assembly | +| PSU | Power Supply Unit | +| RAM | Random Access Memory | +| RMD | Raw Material Depletion | +| SSD | Solid-State Disc | +| SMART | Self-Monitoring, Analysis, and Reporting Technology | +| STB | Set-Top Box | +| WD | Water Depletion | +| xDSL | any type of Digital Subscriber Line | + +## 5 Conventions + +None. + +# 6 Business models + +Previous methods include [b-Tasaki] and [b-Goldey]. + +[b-Tasaki] proposes a method in which replacement conditions of products are compared with iso-environmental-load lines to determine the appropriateness of replacement. + +A theoretical limit of 50% environmental impact reduction for one remanufacturing cycle for ICT infrastructure goods has been proposed [b-Goldey]. + +### 6.1 Desktop computing as a service per hour via different business models + +Electronic devices such as desktops, laptops or mobile phones are said to be reused when they have already been manufactured, are used and maintained in good use for a few years by an organization, and then are discarded by the initially envisaged use and user. While most are still operational, they are disposed of or recycled unless they are repaired, remanufactured, refurbished or redistributed to other users. These devices are collected by a second-hand agent or sent to a remanufacturer for processing, sale or rent, and redistributed to other users. The reuse process ends when, after a few years, the device or a component returns to the disposal state, which means its useful value then, even if improvements were made, no longer allows its reuse. That process should end in recycling, a process that transforms computational use value into raw material use value [b-Franquesa 2018]. The eReuse initiative works with social enterprises in Spain that collect and refurbish desktop and laptop devices donated by public and private organizations (numbering over 10 000 in the last 5 years). These computing devices are sold for a price that reflects the cost of refurbishment and carry a guarantee for a 1-2 year period. In the case of a fault, devices are replaced instead of repaired *in situ*. Several recipient organizations like schools prefer to pay a yearly fee or sign a contract for a number of computing units with an agreed performance level (computing as a service). They receive some additional computer units to ensure quick replacement of any that are faulty. + +The eReuse field study reported in [b-Franquesa 2019] collects data (public dataset from October 2013 to May 2019) about desktop and laptop devices beyond their first usage (reuse) [b-Franquesa 2020]. In reuse, nearly all devices are refurbished with reused components, except new batteries and hard disc drives (HDDs), when they raise signals of failures (by self-monitoring, analysis, and reporting technology; SMART). The dataset shows durability per manufacturer (90th percentile among devices from the same manufacturer) of the total usage period, up to 46 477 h (5.3 years) and a maximum of 65 332 h (7.5 years), consistent with [b-Ardente]. The concept of energy proportional computing (see clause 3.2.4) is significant for the use stage of servers, although it may have been neglected in the LCA in [b-Ardente], but is less important for personal computers. [b-Franquesa 2019] and the corresponding public dataset [b-Franquesa 2020] found that reuse can contribute to approximately a duplication of lifespan in personal computers, especially in a servitized model with network data storage, where faulty computers can be easily replaced by *in-situ* spares. + +The life cycle environmental impacts of a desktop computer can be roughly estimated by creating an environmental intensity per mass for a server [b-Ardente] and multiplying by 5 kg desktops [b-Franquesa 2019]) and assuming that the power consumption of a desktop is one-third of the server. The results for desktops are shown in Table 1. + +**Table 1 – Summary of approximate life cycle environmental impacts of a desktop without refurbishment** + +| Environmental impact category | Manufacturing | Use | End-of-life | +|-------------------------------------------------------------------------|---------------|----------|-------------| +| GWP, kg CO 2 e | 154 | 1 025 | –11 | +| ADP, kg Sb-e | 0.02 | 0.000 18 | –0.013 | +| CED, MJ | 2 288 | 23 834 | –125 | +| CO 2 e: carbon dioxide equivalent; Sb-e: antimony equivalent | | | | + +If the scenario is translated to a computing as a service or servitized model, environmental impacts per device and per hour (of availability and possible usage of a computing device) can be examined and compared. If Table 1 represents the impact of the first usage cycle of a new computer, Table 2 represents the expected potential effect of reuse after refurbishment in comparison to the use of two new devices (as in clause 6.2). Reuse roughly results in doubling of usage hours by a new user, usually + +with lighter computing requirements, but the same manufacturing and end-of-life impacts. There is an assumption in the comparison of a 20% improvement in power consumption in the case of a second new device, and the small impact of local refurbishment and local repair is not accounted for. + +**Table 2 – Summary of idealized impacts from reuse, 5 year baseline usage ( $I_15$ ): one device with reuse for twice the lifespan ( $I_110$ ) compared to two devices without reuse ( $I_210$ ) for a period of $2 \times 5$ years** + +| Environmental impact | One device | | Two devices | Impact improvement (%) | | +|-----------------------------------|----------------------------------------|--------------------------------------------------|-----------------------------------------|-------------------------------------------|-----------------------------------------------| +| | One use, 5 years
$I_15 = M + U + E$ | Use + reuse:
10 years
$I_110 = M + 2U + E$ | $5 + 5$ years
$I_210 = 2(M + U + E)$ | One to two users
$(I_15 - I_110)/I_15$ | Two to one devices
$(I_210 - I_110)/I_110$ | +| GWP, kg CO 2 e (total) | 1 168 | 2 193 | 2 336 | | 7 | +| ADP, kg Sb-e (total) | 0.007 18 | 0.007 36 | 0.014 36 | | 95 | +| CED, MJ (total) | 25 997 | 49 831 | 46 794.6 | | –6 | +| GWP, g CO 2 e/h | 26.7 | 25.0 | 26.7 | 6 | 7 | +| ADP, mg Sb-e/h | 0.2 | 0.1 | 0.2 | 49 | 95 | +| CED, KJ/h | 593.5 | 568.8 | 534.2 | 4 | –6 | + +The impact of use is highly dependent on electricity production (CO2 emissions), but the increasing use of renewable and local sources tends to reduce this contribution over time (in the two device scenario, Table 2 assumes a reduction to 80% of energy consumption for the second). Transparency is crucial for LCA calculations. + +### 6.2 Practical approach showing SEEQ business model + +A first approach compares the environmental footprints of the two following scenarios. + +- Baseline scenario: one product is sold to each successive customer, denoted not refurbished and highlighted in red in Figure 1. This scenario requires the manufacture of two devices (denoted M1 and M2 in Figure 1), their distribution to customers (denoted D1 and D2 in Figure 1), as well as their end-of-life treatment (denoted E1 and E2 in Figure 1). Both pieces of equipment are used by customers involving environmental impacts denoted U1 and U2 in Figure 1. +- Refurbishment scenario: the products are rented to customers, recovered to be refurbished and then shipped to other customers. In Figure 1, this scenario is denoted refurbished and highlighted in green. This scenario involves the manufacture of the first device (denoted M1 in Figure 1), its distribution and use by the first customer (denoted D1 and U1 in Figure 1). The device is then recovered to replace some parts in order to reach a condition that is as-good-as-new (operation denoted R1 in Figure 1). The device is then shipped to a second customer who will use it (denoted D2 and U2, respectively, in Figure 1). Finally the device is sent for end-of-life treatment (denoted E1 in Figure 1). + +In Figure 1, the lifespan is considered to be 5 years for both scenarios. This duration has to be adapted depending on the type of equipment (shorter for small electronic devices, longer for large network equipment for example). + +![Figure 1: Comparison of refurbishment and baseline scenarios over time.](d4af765160d04ecef538e5066006dc77_img.jpg) + +The diagram illustrates two product lifecycle scenarios over a timeline from $t = 0$ to $t = 5$ years, with a key point at $t = \text{New customer}$ . + +- Refurbished (Green):** At $t = 0$ , the sequence is **M1** (Device manufacturing) followed by **D1 U1** (Distribution and Usage). At $t = \text{New customer}$ , the sequence is **R1** (Refurbishment) followed by **D2 U2** (Distribution and Usage). At $t = 5$ years, the sequence ends with **E1** (End-of-life). +- Not refurbished (Red):** At $t = 0$ , the sequence is **M1** followed by **D1 U1**. At $t = \text{New customer}$ , the sequence is **M2 E1** (Manufacturing a new device and ending the life of the old one) followed by **D2 U2**. At $t = 5$ years, the sequence ends with **E2**. + +Legend: + +- Device manufacturing: M +- Distribution: D +- Usage: U +- Refurbishment: R +- End-of-life: E + +L.1024(21)\_F01 + +Figure 1: Comparison of refurbishment and baseline scenarios over time. + +**Figure 1 – Different steps to be considered in a comparison between a scenario including refurbishment and a baseline scenario without refurbishment [b-Vaija]** + +For the refurbishment scenario, it is important to have a good understanding of the reverse logistics supply chain in order to assess correctly the environmental footprint of the different steps. Figure 2 shows details of the different operations that can be involved. The first part of the figure (highlighted in orange) describes the different pathways to recover equipment from the customer. The second part (highlighted in blue) aids comprehension of the first sorting steps, which separate the different grades of product received by the sorting centre (from old product no longer required to be returned to the market to no-fault-found products). The third part (highlighted in green) shows the different parties that can be involved: a third party company operating a refurbishment centre for mechanical part swaps; and a manufacturer for repair requiring, for example, operations on a printed circuit board assembly (PCBA) board. The last part (highlighted in pink) concerns packaging and shipping. System operation also requires input of spare parts (highlighted in yellow) and handling the end-of-life of old equipment and defective parts (highlighted in grey). + +The following factors will also be crucial to the calculation of the environmental footprint of the refurbishment scenario. + +- Recovery rate of equipment from the first customer. Every time a device is not recovered for refurbishment, it means a new one will have to be manufactured. +- Sorting centre location. If equipment has to be shipped over long distances, it will have detrimental effects on the environmental footprint. +- Percentages of no-fault-found equipment and that with a certain type of failure. Depending on the type of failure, the equipment can be categorized as reparable or beyond repair due to the cost of the operation. A device that cannot be repaired will have to be replaced by a new one. +- Percentage of replacement for different parts. External parts that are prone to wear or visible can have a very high replacement rate (e.g., highly glossy top housing plastics parts on consumer electronic equipment). Failure to consider refurbishment of a device during the initial design phases can lead to a 100% replacement rate for some parts. + +![Flowchart of the refurbishment reverse logistics supply chain. The process starts with 'Customer' at the top, leading to 'Operator shop', 'Pick-up point', and 'Exchange at home'. These lead to 'Logistics company hub', which leads to 'Sorting/ test centre'. From 'Sorting/ test centre', the flow splits into 'No-fault found devices', 'Faulty devices', and 'Device struck by lightning'. 'No-fault found devices' lead to 'Mechanical part replacement', which leads to 'Refurbished devices repackaging'. 'Faulty devices' lead to 'Manufacturer repair plant', which leads to 'Refurbished devices repackaging'. 'Device struck by lightning' lead to 'WEEE recycling'. 'Refurbished devices repackaging' leads to 'Operator central warehouse'. 'New spare parts' also lead to 'Refurbished devices repackaging'. 'Outdated devices recycling' is also shown as an output from 'Sorting/ test centre'.](af7916c89a458fdab6c3f443217388ae_img.jpg) + +``` + +graph TD + Customer[Customer] --> Operator_shop[Operator shop] + Customer --> Pick_up_point[Pick-up point] + Customer --> Exchange_at_home[Exchange at home] + Operator_shop --> Logistics_company_hub[Logistics company hub] + Pick_up_point --> Logistics_company_hub + Exchange_at_home --> Logistics_company_hub + Logistics_company_hub --> Sorting_test_centre[Sorting/ test centre] + Sorting_test_centre --> No_fault_found_devices[No-fault found devices] + Sorting_test_centre --> Faulty_devices[Faulty devices] + Sorting_test_centre --> Device_struck_by_lightning[Device struck by lightning] + Sorting_test_centre --> Outdated_devices_recycling[Outdated devices recycling] + No_fault_found_devices --> Mechanical_part_replacement[Mechanical part replacement] + Faulty_devices --> Manufacturer_repair_plant[Manufacturer repair plant] + Device_struck_by_lightning --> WEEE_recycling[WEEE recycling] + Mechanical_part_replacement --> Refurbished_devices_repackaging[Refurbished devices repackaging] + Manufacturer_repair_plant --> Refurbished_devices_repackaging + Refurbished_devices_repackaging --> Operator_central_warehouse[Operator central warehouse] + New_spare_parts[New spare parts] --> Refurbished_devices_repackaging + +``` + +Flowchart of the refurbishment reverse logistics supply chain. The process starts with 'Customer' at the top, leading to 'Operator shop', 'Pick-up point', and 'Exchange at home'. These lead to 'Logistics company hub', which leads to 'Sorting/ test centre'. From 'Sorting/ test centre', the flow splits into 'No-fault found devices', 'Faulty devices', and 'Device struck by lightning'. 'No-fault found devices' lead to 'Mechanical part replacement', which leads to 'Refurbished devices repackaging'. 'Faulty devices' lead to 'Manufacturer repair plant', which leads to 'Refurbished devices repackaging'. 'Device struck by lightning' lead to 'WEEE recycling'. 'Refurbished devices repackaging' leads to 'Operator central warehouse'. 'New spare parts' also lead to 'Refurbished devices repackaging'. 'Outdated devices recycling' is also shown as an output from 'Sorting/ test centre'. + +**Figure 2 – Details of the refurbishment reverse logistics supply chain (adapted from [b-Vaija])** + +The environmental impact results for both systems can then be calculated with LCA methods, as described in [ITU L.1410]. Figure 3 shows an example for both the scenarios described in Figure 1. + +![Bar chart comparing environmental footprints for two scenarios: '5 years with one refurbishment' (blue bars) and '5 years without refurbishment' (red bars) across four indicators: Primary energy depletion, Global warming potential, Raw material depletion, and Water depletion. The chart shows that the refurbishment scenario has lower environmental impacts across all indicators.](98ee20ceb85cd84e2415b20b1eda1bcf_img.jpg) + +| Indicator | 5 years with one refurbishment | 5 years without refurbishment | +|--------------------------|--------------------------------|-------------------------------| +| Primary energy depletion | 100 | 106.01 | +| Global warming potential | 100 | 125 | +| Raw material depletion | 100 | 175 | +| Water depletion | 100 | 120 | + +Bar chart comparing environmental footprints for two scenarios: '5 years with one refurbishment' (blue bars) and '5 years without refurbishment' (red bars) across four indicators: Primary energy depletion, Global warming potential, Raw material depletion, and Water depletion. The chart shows that the refurbishment scenario has lower environmental impacts across all indicators. + +**Figure 3 – Environmental footprint comparison between the baseline (equipment sold to customers) and refurbishment scenarios (equipment rented to customers) [b-Vaija]** + +Figure 3 shows that, in this example, the impact of all environmental indicators is lower for the refurbishment scenario. For primary energy depletion (ED), the difference is low (6.01%) in the usage phase, equal to U1 + U2 for both systems (as shown in Figure 1), which contributes 92.6% for this indicator. Scores for such indicators as global warming potential (GWP) and water depletion (WD) + +are mainly related to the usage phase (72.0% for GWP and 73.2% for WD), therefore refurbishment benefit is a little better than for ED. + +As metals like silver, gold, tin or copper have relatively high characterization factors in the raw material depletion (RMD) method, the benefit of refurbishment is really visible for this indicator. Indeed, the refurbishment effort is mostly about mechanical parts replacement, while the motherboard is most often retained (electric defaults due to surges from lightning strikes on any type of digital subscriber line (xDSL) input or on the power line are examples of causes for motherboard replacement). Thus, the impact of the refurbishment step R1 is rather low for the RMD indicator, while the manufacture of a second device (M2) for the system without refurbishment requires gold for integrated circuit wire bonding, tin and silver for solder paste, copper for printed circuit board (PCB) conductive layers, etc. + +The method used in clause 6.2 is similar to that in [b-Goldey]. + +#### 6.2.1 Further explanation of calculation procedures + +As the modelling includes energy efficiency improvement and energy consumption effects of additional functions, in the name of readability, the two following examples only focus on the carbon footprint calculation instead of the four indicators detailed in Figure 3. + +##### a) First example considering energy consumption effects + +In the first example (see Figure 4), the carbon footprint of the three following scenarios is compared. + +- Scenario 1: a rather complex and energy hungry device (denoted model A) is manufactured (① in Figure 4) and rented to a first customer. After 30 months, the equipment is recovered by the telecommunication operator (the owner of the device) to carry out a refurbishment operation (③ in Figure 4). The equipment is then shipped to a second customer for 30 months of use. A second recovery and refurbishment step happens at the end of the life cycle (⑤ in Figure 4). The device is then shipped to the third and last customer for 30 months of use. At the end, i.e., 90 months after the introduction of the device, the equipment is sent to end-of-life treatment (⑦ in Figure 4). To summarize, scenario 1 requires: one complex device manufacturing and shipping operation; two recovery and refurbishment operations; two shipping operations from the refurbishment centre; and one end-of-life treatment operation. +- Scenario 2: the first 30 months of scenario 2 are the same as in scenario 1 (① in Figure 4). After 30 months, model A of the equipment is sent to end-of-life treatment instead of being refurbished. A more simple and energy efficient device (denoted model B in Figure 4) is manufactured and shipped to the second customer (② in Figure 4). After an additional 30 months, this model B device is also recovered, sent to refurbishment and shipped to a third customer (④ in Figure 4). At the end of the scenario (i.e., 90 months after the beginning) the equipment is sent to end-of-life treatment (⑥ in Figure 4). To summarize, scenario 2 requires: one complex device and one less complex device manufacturing and shipping operations; one recovery and refurbishment operation; one shipping operation from the refurbishment centre; and two end-of-life treatment operations. +- Scenario 3: the first 30 months of scenario 3 are the same as in scenarios 1 and 2 (① in Figure 4). After 30 months, model A of the equipment is sent to end-of-life treatment and another model A is manufactured and shipped to the second customer (⑧ in Figure 4). After an additional 30 months, this second model A device is sent to end-of-life treatment and a third model A is manufactured and shipped to the third customer (⑨ in Figure 4). At the end of the scenario (i.e., 90 months after the beginning) the equipment is sent to end-of-life treatment (⑩ in Figure 4). To summarize, scenario 3 requires: three complex device manufacturing, shipping and end-of-life treatment operations. + +![Figure 4: Carbon footprint comparison between three scenarios over 90 months. The y-axis is 'Carbon footprint (Footprint for scenario 1 at 90 month is equal to 100)' ranging from 0 to 140. The x-axis is 'Months' ranging from 0 to 90. Scenario 1 (blue line with circles) starts at ~25, increases to ~50 at 30 months, ~75 at 60 months, and ends at 100 at 90 months. Scenario 2 (orange line with circles) starts at ~25, increases to ~60 at 30 months, ~75 at 60 months, and ends at ~90 at 90 months. Scenario 3 (purple line with circles) starts at ~25, increases to ~70 at 30 months, ~90 at 60 months, and ends at ~140 at 90 months. Numbered circles 1-10 mark key events along the curves.](71ab4df17511d75261da8d462d643b1a_img.jpg) + +Carbon footprint (Footprint for scenario 1 at 90 month is equal to 100) + +Months + +Scenario 1: Model A for 30 + 30 + 30 months + +Scenario 2: Model A for 30 months then model B for 30 + 30 months + +Scenario 3: 3 Model A sold (each one for 30 months) + +① For all 3 scenarios: Manufacturing and shipping of one model A gateway + ② For scenario 2: End of life of model B + manufacturing and shipping of one model B gateway + ③ For scenario 1: Refurbishment of model A + ④ For scenario 2: Refurbishment of model B + ⑤ For scenario 1: Refurbishment of model A + ⑥ For scenario 2: End of life of model B + ⑦ For scenario 1: End of life of model A + ⑧ For scenario 3: End of life of model A + manufacturing and shipping of one model A gateway + ⑨ For scenario 3: End of life of model A + manufacturing and shipping of one model A gateway + ⑩ For scenario 3: End of life of model A + +L.1024(21)\_F04 + +Figure 4: Carbon footprint comparison between three scenarios over 90 months. The y-axis is 'Carbon footprint (Footprint for scenario 1 at 90 month is equal to 100)' ranging from 0 to 140. The x-axis is 'Months' ranging from 0 to 90. Scenario 1 (blue line with circles) starts at ~25, increases to ~50 at 30 months, ~75 at 60 months, and ends at 100 at 90 months. Scenario 2 (orange line with circles) starts at ~25, increases to ~60 at 30 months, ~75 at 60 months, and ends at ~90 at 90 months. Scenario 3 (purple line with circles) starts at ~25, increases to ~70 at 30 months, ~90 at 60 months, and ends at ~140 at 90 months. Numbered circles 1-10 mark key events along the curves. + +**Figure 4 – Carbon footprint comparison between scenario 1 (model A used 90 months with two refurbishments), scenario 2 (model A sold and used for 30 months and then replaced by model B used for 60 months with one refurbishment) and scenario 3 (three model A devices sold and used for 30 months each)** + +At the end of the life cycle (i.e., after 90 months) – even if scenario 2 requires the manufacture of an additional device (② in Figure 4) – the achieved carbon footprint is lower. This is achieved thanks to the lower energy consumption and better energy efficiency of model B compared to model A. Scenario 3, which requires the manufacture of three complex devices each with a high energy consumption, is characterized by the highest carbon footprint among the three scenarios. + +##### b) Second example considering energy consumption effects + +In the first example (see Figure 5) the carbon footprint of the two following scenarios are compared. + +- Scenario 1: a rather complex and energy hungry device (denoted model A) is manufactured (① in Figure 5) and rented to a first customer. After 30 months, the equipment is recovered by the telecommunication operator (the owner of the device) to carry out a refurbishment operation (② in Figure 5). The equipment is then shipped to a second customer for 30 months of use. A second recovery and refurbishment step happens at the end of the life cycle (④ in Figure 5). The device is then shipped to the third and last customer for 30 months of use. At the end, i.e., 90 months after the introduction of the device, the equipment is sent to end-of-life treatment (⑥ in Figure 5). To summarize, scenario 1 requires: one complex device manufacturing and shipping operation; two recovery and refurbishment operations; two shipping operations from the refurbishment centre; and one end-of-life treatment operation. + +- Scenario 2: the first 30 months of scenario 2 are the same as in scenario 1 (① in Figure 5). After 30 months, model A of the equipment is sent to end-of-life treatment instead of being refurbished. A more simple and energy efficient device (denoted model B in Figure 5) is manufactured and shipped to a second customer (③ in Figure 5). After an additional 30 months, this model B device is sent to end-of-life treatment and another model is manufactured and shipped to a third customer (⑤ in Figure 5). At the end of the scenario (i.e., 90 months after the beginning) the equipment is sent to end-of-life treatment (⑦ in Figure 5). To summarize, scenario 2 requires: manufacture of one complex device and two less complex devices; one shipping and end-of-life treatment operation for all. + +![Figure 5: Carbon footprint comparison between scenario 1 and scenario 2. The graph shows carbon footprint (0-120) over 90 months. Scenario 1 (blue line) starts at 20, increases to 45 at 30 months, 70 at 60 months, and 100 at 90 months. Scenario 2 (orange line) starts at 20, increases to 45 at 30 months, then jumps to 60 at 30 months, 85 at 60 months, and 100 at 90 months. An inset shows a zoomed-in view of the 80-90 month period where the lines cross.](b05fbb6a015ea153c1e25245772b1a1b_img.jpg) + +Carbon footprint (Footprint for scenario 1 at 90 month is equal to 100) + +Months + +120 + +100 + +80 + +60 + +40 + +20 + +0 + +0 10 20 30 40 50 60 70 80 90 + +Legend: + +- 1 Model A refurbished three times during 90 months +- 1 Model A sold (30 months lifespan) + 2 model B devices sold (30 months lifespan each) + +① For both scenarios: Manufacturing and shipping of one model A gateway + +② For scenario 1: Refurbishment of model A + +③ For scenario 2: End of life of model A + manufacturing and shipping of one model B gateway + +④ For scenario 1: Refurbishment of model A + +⑤ For scenario 2: End of life of model B + manufacturing and shipping of one model B gateway + +⑥ For scenario 1: End of life of model A + +⑦ For scenario 2: End of life of model B + +L.1024(21)\_F05 + +Figure 5: Carbon footprint comparison between scenario 1 and scenario 2. The graph shows carbon footprint (0-120) over 90 months. Scenario 1 (blue line) starts at 20, increases to 45 at 30 months, 70 at 60 months, and 100 at 90 months. Scenario 2 (orange line) starts at 20, increases to 45 at 30 months, then jumps to 60 at 30 months, 85 at 60 months, and 100 at 90 months. An inset shows a zoomed-in view of the 80-90 month period where the lines cross. + +**Figure 5 – Carbon footprint comparison between scenario 1 (model A used 90 months with two refurbishments) and scenario 2 (model A sold and used for 30 months and then replaced by two successive model B devices sold and used for 30 months each)** + +With this configuration, the lower energy consumption and better energy efficiency of model B is not enough to compensate for the additional environmental burden related to the manufacture of two model B devices. Thus, scenario 2 is worse regarding the carbon footprint at the end of the 90 months of the life cycle (see inset in Figure 5 as the results are quite close). + +When comparing different business models such as rent and refurbish vs. sell and recycle, the two examples in Figure 4 and Figure 5 show that comparative environmental footprint analysis of refurbishment shall consider the following parameters. + +- Each instance of equipment manufacture, e.g., model A and model B. + +- Transport of each device upstream and downstream (e.g., from parts components or sub-assembly supplier factories to final assembly plant; from final assembly plant to use location). +- Energy consumption of each device. Note that if one device has vastly better capabilities (such as number of clients served, system capacity, etc.), the energy consumption should be scaled according to the specifications of the other equipment for a correct comparison, as it is done in comparative LCA functional units. +- End-of-life treatment of each equipment. +- For equipment undergoing refurbishment: + - if recovery rate is <100%, the manufacture of an additional device; + - whether parts, components or sub-assemblies require replacement due to wear or need an update; + - an allocation of the refurbishment plant energy or ancillary materials consumption. + +The lifespan of each device in both scenarios should also be adjusted according to actual data. + +# 7 Analytical approaches + +Another approach useful in the context of this Recommendation is a framework of mathematical equations [b-Ardente], e.g., Equation 1, by which the environmental benefit of remanufacturing and refurbishment of ICT goods can be estimated. That framework and formulae will here be re-verified and explained for the enterprise server in [b-Ardente] and then applied to some other ICT goods. + +$$\delta_i = 1 + \frac{(\Delta P_j - P_{RE,j})}{U_{A,j}} \quad (1)$$ + +$\delta_i$ is the environmental benefit for impact category $j$ of remanufacturing; + +$\Delta P_j$ is the potential environmental impact for impact category $j$ of parts of the ICT good that are new in baseline scenario A and reused in scenario B; + +NOTE 1 – Simply put, this term represents the potential environmental impacts of manufacturing reusable parts (as in Tables 2, 4, 6, 8 and 10). + +$P_{RE,j}$ is the potential environmental impact, relative to the impact category $j$ , resulting from the reuse of parts for the remanufacturing scenario + +NOTE 2 – The impact is assumed to be very low at 0.5% of those for the production of the part. Reused parts are extracted from other products (during some stage of their life cycle) and are used as inputs for the remanufacture of product B. The percentage will be higher if extensive repairs of the parts are necessary. + +$U_{A,j}$ is the potential lifetime environmental impact from using product A for impact category $j$ + +### 7.1 Remanufacturing trade-off for enterprise server + +Scores like those in Table 3 can be obtained by using the LCA standard [ITU-T L.1410]. The re-use rates in Table 4 are used to identify which parts to include in Equation 1. + +**Table 3 – Summary of approximate environmental impacts of the life cycle of an enterprise server without remanufacturing (scenario A) [b-Ardente]** + +| Environmental impact category | Manufacturing | Use (4 years) | End-of-life | +|-------------------------------|---------------|---------------|-------------| +| GWP, kg CO 2 e | 858.3 | 3 077.2 | –58.9 | +| ADP, kg Sb-e | 0.11 | 0.001 | –0.07 | +| CED, MJ | 12 724 | 71 500 | –696 | + +**Table 4 – Hypotheses for reused parts of server and reuse rates [b-Ardente]** + +| Sub-part | Mass (g) | kg CO 2 e, GWP/piece | kg Sb-e, ADP/piece | Re-use rate (%) | +|----------------|----------|---------------------------------|--------------------|-----------------| +| HDD | 1 750 | 83 | 0.01 | 47.7 | +| Memory cards | 135 | 140 | 0.013 | 40.1 | +| CPUs | 54 | 200 | 0.028 | 5.2 | +| Power supply | 3 426 | 340 | 0.004 3 | 5.0 | +| Motherboard | 1 662 | 210 | 0.029 | 2.7 | +| Raid card | 5.2 | 0.37 | 0.000 023 | 2.1 | +| Chassis | 13 454 | 99 | 0.004 7 | 1.4 | +| Expansion card | 349 | 50 | 0.007 8 | 0.7 | + +Applying Equation 1 to remanufacturing the server with reused HDD and memory cards leads to Equation 2 and Equation 3: + +$$\delta_{\text{GWP,server}} = 1 + \frac{(\Delta P_{\text{GWP}} - P_{\text{RE,GWP}})}{U_{\text{A,GWP}}} = 1 + \frac{[(83+140) - 0.5\% \times (83+140)]}{3077.2} = 1.07 \quad (2)$$ + +$$\delta_{\text{ADP,server}} = 1 + \frac{(\Delta P_{\text{ADP}} - P_{\text{RE,ADP}})}{U_{\text{A,GWP}}} = 1 + \frac{[(0.01+0.013) - 0.5\% \times (0.01+0.013)]}{0.001} = 23.9 \quad (3)$$ + +The higher the value of $\delta$ , the higher the environmental benefit. + +Equation 2 suggests that remanufacturing is not environmentally beneficial when the energy consumption of the remanufactured server is more than 7% higher than the energy consumption of a new server. + +### 7.2 Refurbish trade-off for smartphone + +Here the analytical approach is applied to a contemporary smartphone. Scores like those in Table 5 can be obtained by using the LCA standard [ITU-T L.1410]. + +**Table 5 – Summary of approximate life cycle environmental impacts of a smartphone without refurbishment** + +| Environmental impact category | Manufacturing | Use (4 years) | End-of-life | +|-------------------------------|---------------|---------------|-------------| +| GWP, kg CO 2 e | 43 | 8.6 | -1.5 | +| ADP, g Sb-e | 12 | 0.5 | -2.6 | + +Several typical LCA results exist and the practitioner can choose the best available scores to fit the purpose. The re-use rates in Table 6 are used to identify which parts to include in Equation 1. + +**Table 6 – Hypotheses for reused parts of smartphone and reuse rates** + +| Sub-part | kg CO 2 e, GWP/piece | g Sb-e, ADP/piece | Re-use rate (%) | +|-------------|---------------------------------|-------------------|-----------------| +| Screen | 4.8 | 1.5 | | +| Battery | 1.8 | 2.7 | | +| Charger | 1 | 1.1 | | +| Motherboard | 19 | 6.7 | | +| Cover | 2.2 | | | + +Applying Equation (1) to refurbish a smartphone with a reused screen and charger leads to Equation 4 and Equation 5: + +$$\delta_{\text{GWP,smartphone}} = 1 + \frac{(\Delta P_{\text{GWP}} - P_{\text{RE,GWP}})}{U_{\text{A,GWP}}} = 1 + \frac{[(4.8+1) - 0.5\% \times (4.8+1)]}{8.6} = 1.67 \quad (4)$$ + +$$\delta_{\text{ADP,smartphone}} = 1 + \frac{(\Delta P_{\text{ADP}} - P_{\text{RE,ADP}})}{U_{\text{A,GWP}}} = 1 + \frac{[(1.5+1.1) - 0.5\% \times (1.5+1.1)]}{0.5} = 6.17 \quad (5)$$ + +The higher the value of $\delta$ , the higher the environmental benefit. + +Equation 4 suggests that refurbishment is not CO2 beneficial when the energy consumption of the refurbished smartphone is more than 67% higher than the energy consumption of a new smartphone. + +#### 7.2.1 Direct reuse benefits + +Applying Equation 1 to refurbish the smartphone with all sub-parts reused leads to Equation 6 and Equation 7: + +$$\delta_{\text{GWP,smartphone}} = 1 + \frac{(\Delta P_{\text{GWP}} - P_{\text{RE,GWP}})}{U_{\text{A,GWP}}} = 1 + \frac{[(43) - 0.5\% \times (43)]}{8.6} = 5.9 \quad (6)$$ + +$$\delta_{\text{ADP,smartphone}} = 1 + \frac{(\Delta P_{\text{ADP}} - P_{\text{RE,ADP}})}{U_{\text{A,GWP}}} = 1 + \frac{[(1.5+2.7+1.1+6.7) - 0.5\% \times (1.5+2.7+1.1+6.7)]}{0.5} = 24.9 \quad (7)$$ + +The higher the value of $\delta$ , the higher the environmental benefit. + +Equation 6 suggests that a small refurbishment and direct reuse – perhaps without disassembly – is more CO2 beneficial than Equation 4 featuring disassembly, reuse of two parts and reassembly. + +### 7.3 Set-top box refurbish trade-offs + +Here the analytical approach is applied to the example in clause 6.2. See Tables 7 and 8. + +**Table 7 – Summary of approximate life cycle environmental impacts of a set-top box without refurbishment** + +| Environmental impact category | Manufacturing | Use | End-of-life | +|-------------------------------|---------------|--------|-------------| +| GWP, kg CO 2 e | 27.86 | 61.10 | 0.59 | +| ADP, g Sb-e | 4.49 | 0.014 | 0.000 018 | +| ADP fossil, MJ | 189.30 | 350.00 | 3.33 | + +**Table 8 – Hypotheses for reused parts of a set-top box and reuse rates** + +| Part | kg CO 2 e,
GWP/piece | g Sb-e,
ADP/piece | Re-use rate
(%) | +|---------------------------------------------------------------------------------------------|------------------------------------|----------------------|--------------------| +| Power supply unit | 3.02 | 0.492 | 65 | +| Registered jack 45 cable | 0.27 | 0.027 | 40 | +| Société des Constructeurs d'Appareils Radiorécepteurs et Téléviseurs (SCART) standard cable | 0.46 | 0.018 | 40 | +| Remote control unit | 1.15 | 0.081 | 55 | +| Top housing part | 2.44 | 0.000 064 | 30 | +| Bottom housing part | 1.70 | 0.000 045 | 60 | +| Printed circuit board assembly | 18.37 | 3.87 | 95 | +| Kitting (primary packaging and documentation) | 0.45 | 0.000 24 | 0 | + +Applying Equation 1 to refurbish the set-top box (STB) with reused PCBA, power supply unit (PSU) and bottom housing part leads to Equation 8 and Equation 9: + +$$\delta_{\text{GWP,STB}} = 1 + \frac{(\Delta P_{\text{GWP}} - P_{\text{RE,GWP}})}{U_{\text{A,GWP}}} = 1 + \frac{[(18.37+3.02+1.7) - 0.5\% \times (18.37+3.02+1.7)]}{61.1} = 24.09 \quad (8)$$ + +$$\begin{aligned} +\delta_{\text{ADP,STB}} &= 1 + \frac{(\Delta P_{\text{ADP}} - P_{\text{RE,ADP}})}{U_{\text{A,GWP}}} \\ +&= 1 + \frac{[(3.87 + 0.492 + 0.000\,045) - 0.5\% \times (3.87 + 0.492 + 0.000\,045)]}{0.014} \\ +&= 311 +\end{aligned} \tag{9}$$ + +The higher the value of $\delta$ , the higher the environmental benefit. + +Equation 8 suggests that refurbishment is not CO2 beneficial when the energy consumption of the refurbished STB is likely not more than 24 times higher than the energy consumption of a new STB. + +### 7.4 Desktop box refurbish trade-offs + +Here the analytical approach is applied to the example in clause 6.1 considering those parts of a desktop or laptop [b-André] personal computer are reused (most) and those replaced with new parts. + +**Table 9 – Summary of approximate life cycle environmental impacts of a desktop without refurbishment [b-Song]** + +| Environmental impact category | Manufacturing | Use | End-of-life | +|-------------------------------|---------------|------|-------------| +| GWP, kg CO 2 e | 444 | 1340 | 3.28 | +| ADP, kg Sb-e | 3.13 | 8.47 | –0.001 | +| CED, MJ | N/A | N/A | N/A | + +Contrary to the server scenario in [b-Ardente], in the personal computer refurbishment reported in clause 6.1, the computer is mostly reused, except that the motherboard button battery is replaced by a new one, as they are usually exhausted. Data storage components (HDDs) can change too. Some organizations with stringent data protection policies dispose of computers without the HDD, which is destroyed separately to prevent data leaks. Some HDDs are replaced by reused HDDs or solid-state discs (SSDs) when failing in a diagnostic and stress test or when the drive has had too many usage hours. Sometimes random access memory (RAM) capacity is expanded (if there is room) with RAM chips extracted from equivalent but faulty computers, avoiding additional impacts. + +Table 10 summarizes the impacts of the replaced components, negligible to the overall impact of the device (storage data from [b-Boyd]). + +**Table 10 – Hypotheses for replaced by new and reused parts of desktops** + +| Part | kg CO 2 e, GWP/piece | g Sb-e, ADP/piece | +|----------------------------------|---------------------------------|-------------------| +| New battery (button) | 0.489 | 1.69 | +| New storage (boot drive) | 8.6 (HDD) to 28 (SSD) | <0.011 | +| Reused desktop (remaining parts) | 1 778.191 | 9.898 | + +Applying Equation 1 to refurbish a desktop computer reusing all except battery and data leads to Equation 10 and Equation 11: + +$$\delta_{\text{GWP,desktop}} = 1 + \frac{(\Delta P_{\text{GWP}} - P_{\text{RE,GWP}})}{U_{\text{A,GWP}}} = 1 + \frac{(1\,778.191 - 0.5\% \times 1\,778.191)}{1\,340} = 2.32 \tag{10}$$ + +$$\delta_{\text{ADP,desktop}} = 1 + \frac{(\Delta P_{\text{ADP}} - P_{\text{RE,ADP}})}{U_{\text{A,GWP}}} = 1 + \frac{(9.898 - 0.5\% \times 9.898)}{8.47} = 2.16 \tag{11}$$ + +The higher the value of $\delta$ , the higher the environmental benefit. + +Equation 10 and Equation 11 show the large CO2 margin for refurbishment as 99.49% of GWP and 85.33% of ADP is saved (or 0.51% of GWP and 14.67% of ADP added by the new parts). + +### 7.5 Optical network terminal refurbish trade-offs + +Here the analytical approach is applied to an optical network terminal (ONT). See Tables 11 and 12. + +**Table 11 – Summary of approximate life cycle environmental impacts +of an optical network terminal without refurbishment** + +| Environmental impact category | Manufacturing | Use | End-of-life | +|-------------------------------|---------------|-----------|-------------| +| GWP, kg CO 2 e | 15 | 41 | | +| ADP, g Sb-e | 63 | ~0.000 06 | | +| CED, MJ | | | | + +**Table 12 – Hypotheses for reused optical network terminal parts and reuse rates** + +| Sub-part | kg CO 2 e, GWP/piece | g Sb-e, ADP/piece | Re-use rate (%) | +|----------------|---------------------------------|-------------------|-----------------| +| Optical module | 0.062 | 48 | | +| Signal cable | 0.63 | 7.7 | | +| PSU | 9.2 | 4.3 | | +| Motherboard | 3.9 | 2.5 | | + +Applying Equation 1 to refurbish the ONT with reused Signal cable and PSU leads to Equation 12 and Equation 13: + +$$\delta_{\text{GWP,ONT}} = 1 + \frac{(\Delta P_{\text{GWP}} - P_{\text{RE,GWP}})}{U_{\text{A,GWP}}} = 1 + \frac{[(0.63+9.2) - 0.5\% \times (0.63+9.2)]}{41} = 1.24 \quad (12)$$ + +$$\delta_{\text{ADP,ONT}} = 1 + \frac{(\Delta P_{\text{ADP}} - P_{\text{RE,ADP}})}{U_{\text{A,GWP}}} = 1 + \frac{[(7.7+4.3) - 0.5\% \times (7.7+4.3)]}{0.000 06} = 199\ 000 \quad (13)$$ + +The higher the value of $\delta$ , the higher the environmental benefit. + +Equation 12 suggests that refurbishment is not CO2 beneficial when the energy consumption of the refurbished ONT is more than 24% higher than the energy consumption of a new ONT. + +### 7.6 Base station remanufacturing trade-offs + +Here the analytical approach is applied to a wireless base station from Tables V and VII in [b-Goldey]. See Tables 13 and 14. + +**Table 13 – Summary of approximate life cycle environmental impacts +of a base station without refurbishment** + +| Environmental impact category | Manufacturing | Use | End-of-life | +|-------------------------------|---------------|-----------------------------------------------------------------------|---------------| +| GWP, kg CO 2 e | 2 887 | ~60 000
NOTE – All base stations have different use stage impacts. | 135 | +| ADP, g Sb-e | 14 000 | ~4
NOTE – All base station have different use stage impacts. | Not available | + +**Table 14 – Hypotheses for reused parts of base station and reuse rates** + +| Part | kg CO 2 e,
GWP/piece | g Sb-e,
ADP/piece | Re-use
rate (%) | +|----------------------------------------------------------------------------------------------------------------------------|------------------------------------|----------------------|--------------------| +| Pre-equipped cabinet including shelves | 247 | Not available | 100 | +| Filter unit | 525 | | 100 | +| Amplifier unit | 649 | | 100 | +| Digital shelf unit containing different circuit packs –
standard surface mount (SM) and through-hole (TH)
components | 1 438 | | 100 | +| Cabling | 33 | | 100 | + +Applying Equation 1 to remanufacture with 100% reuse of all sub-parts leads to Equation 14 and Equation 15: + +$$\delta_{\text{GWP,base station}} = 1 + \frac{(\Delta P_{\text{GWP}} - P_{\text{RE,GWP}})}{U_{\text{A,GWP}}} = 1 + \frac{(2\,887 - 0.5\% \times 2\,887)}{60\,000} = 1.05 \quad (14)$$ + +$$\delta_{\text{ADP,base station}} = 1 + \frac{(\Delta P_{\text{ADP}} - P_{\text{RE,ADP}})}{U_{\text{A,GWP}}} = 1 + \frac{(14\,000 - 0.5\% \times 14\,000)}{4} = 4.48 \quad (15)$$ + +The higher the value of $\delta$ , the higher the environmental benefit. + +Equation 14 suggests that refurbishment is not CO2 beneficial when the energy consumption of the refurbished base station is more than 5% higher than the energy consumption of a new base station. It would be even lower if not all parts are reused, and if the remanufacturing cost as well as the use stage impacts are higher. + +## 8 Global change effect of servitization of desktops, laptops and gateways + +### 8.1 Desktops + +Estimates of global shipments are listed in Table 15. + +**Table 15 – Estimated shipments of desktops 2015-2030 [b-Andrae]** + +| | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 | 2027 | 2028 | 2029 | 2030 | +|-----------------------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------| +| Desktops,
millions | 142 | 139 | 136 | 134 | 131 | 128 | 126 | 123 | 121 | 118 | 116 | 114 | 112 | 109 | 107 | 105 | + +Table 16 shows how the global numbers are derived for desktops. + +**Table 16 – Using Table 1 and Table 2 with Table 15** + +| | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 | 2027 | 2028 | 2029 | 2030 | | +|---------------------------------------------------------|--------------------------------------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|-----| +| Scenario A – One use of one desktop over 5 years | | | | | | | | | | | | | | | | | | +| 1 304 kg CO 2 e
(Table 1) | GWP, Mt CO 2 e
(total) | 185 | 182 | 178 | 174 | 171 | 168 | 164 | 161 | 158 | 155 | 151 | 148 | 145 | 143 | 140 | 137 | +| 0.146 4 g Sb-e | ADP, kt Sb-e
(total) | 21 | 20 | 20 | 20 | 19 | 19 | 18 | 18 | 18 | 17 | 17 | 17 | 16 | 16 | 16 | 15 | +| 26 246 MJ | CED, EJ (total) | 3.7 | 3.7 | 3.6 | 3.5 | 3.4 | 3.4 | 3.3 | 3.2 | 3.2 | 3.1 | 3.0 | 3.0 | 2.9 | 2.9 | 2.8 | 2.8 | +| 0.029 771 689 kg
CO 2 e | GWP, t CO 2 e/h | 4.2 | 4.1 | 4.1 | 4.0 | 3.9 | 3.8 | 3.7 | 3.7 | 3.6 | 3.5 | 3.5 | 3.4 | 3.3 | 3.3 | 3.2 | 3.1 | +| 3.342 47E-06 mg
Sb-e | ADP, mg Sb-e/h | 475 | 466 | 456 | 447 | 438 | 429 | 421 | 412 | 404 | 396 | 388 | 380 | 373 | 365 | 358 | 351 | + +**Table 16 – Using Table 1 and Table 2 with Table 15** + +| | | | | | | | | | | | | | | | | | | +|------------------------------------------------------------------|-----------------------------------|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----| +| 0.599 223 744 kJ | CED, GJ/h | 85 | 83 | 82 | 80 | 79 | 77 | 75 | 74 | 72 | 71 | 70 | 68 | 67 | 65 | 64 | 63 | +| Scenario B – One desktop used twice over 10 years | | | | | | | | | | | | | | | | | | +| 2 329 kg | GWP, Mt CO 2 e (total) | 331 | 324 | 318 | 312 | 305 | 299 | 293 | 287 | 282 | 276 | 270 | 265 | 260 | 255 | 249 | 244 | +| 0.146 8 g | ADP, kt Sb-e (total) | 21 | 20 | 20 | 20 | 19 | 19 | 18 | 18 | 18 | 17 | 17 | 17 | 16 | 16 | 16 | 15 | +| 50 079 MJ | CED, EJ (total) | 7.1 | 7.0 | 6.8 | 6.7 | 6.6 | 6.4 | 6.3 | 6.2 | 6.1 | 5.9 | 5.8 | 5.7 | 5.6 | 5.5 | 5.4 | 5.3 | +| 0.026 586 758 kg | GWP, t CO 2 e/h | 3.8 | 3.7 | 3.6 | 3.6 | 3.5 | 3.4 | 3.3 | 3.3 | 3.2 | 3.2 | 3.1 | 3.0 | 3.0 | 2.9 | 2.8 | 2.8 | +| 1.675 8E-06 mg | ADP, mg Sb-e/h | 238 | 233 | 229 | 224 | 220 | 215 | 211 | 207 | 203 | 199 | 195 | 191 | 187 | 183 | 179 | 176 | +| 0.571 678 082 kJ | CED, GJ/h | 81 | 80 | 78 | 76 | 75 | 73 | 72 | 71 | 69 | 68 | 66 | 65 | 64 | 62 | 61 | 60 | +| Scenario C – Two desktops used 5 years each over 10 years | | | | | | | | | | | | | | | | | | +| 2 608 kg | GWP, Mt CO 2 e (total) | 371 | 363 | 356 | 349 | 342 | 335 | 328 | 322 | 315 | 309 | 303 | 297 | 291 | 285 | 279 | 371 | +| 0.292 8 g | ADP, kt Sb-e (total) | 42 | 41 | 40 | 39 | 38 | 38 | 37 | 36 | 35 | 35 | 34 | 33 | 33 | 32 | 31 | 42 | +| 47 242.8 MJ | CED, EJ (total) | 6.7 | 6.6 | 6.4 | 6.3 | 6.2 | 6.1 | 5.9 | 5.8 | 5.7 | 5.6 | 5.5 | 5.4 | 5.3 | 5.2 | 5.1 | 6.7 | +| 0.029 771 689 kg | GWP, t CO 2 e/h | 4.2 | 4.1 | 4.1 | 4.0 | 3.9 | 3.8 | 3.7 | 3.7 | 3.6 | 3.5 | 3.5 | 3.4 | 3.3 | 3.3 | 3.2 | 4.2 | +| 3.342 47E-06 mg | ADP, mg Sb-e/h | 475 | 466 | 456 | 447 | 438 | 429 | 421 | 412 | 404 | 396 | 388 | 380 | 373 | 365 | 358 | 351 | +| 0.539 301 37 kJ | CED, GJ/h | 77 | 75 | 74 | 72 | 71 | 69 | 68 | 67 | 65 | 64 | 63 | 61 | 60 | 59 | 58 | 77 | + +Table 17 shows the increased burden of using two new desktops instead of one. + +**Table 17 – Global effect of using two new desktops over 10 years (scenario C) instead of one new desktop twice over 5 + 5 years, scenario C (business as usual) minus scenario B** + +| | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 | 2027 | 2028 | 2029 | 2030 | +|-----------------------------------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------| +| GWP, Mt CO 2 e (total) | 40 | 39 | 38 | 37 | 37 | 36 | 35 | 34 | 34 | 33 | 32 | 32 | 31 | 30 | 30 | 29 | +| ADP, kt Sb-e (total) | 21 | 20 | 20 | 20 | 19 | 19 | 18 | 18 | 18 | 17 | 17 | 17 | 16 | 16 | 16 | 15 | +| CED, EJ (total) | -0.4 | -0.4 | -0.4 | -0.4 | -0.4 | -0.4 | -0.4 | -0.3 | -0.3 | -0.3 | -0.3 | -0.3 | -0.3 | -0.3 | -0.3 | -0.3 | +| GWP, t CO 2 e/h | 0.5 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.3 | 0.3 | 0.3 | +| ADP, mg Sb-e/h | 237 | 232 | 227 | 223 | 218 | 214 | 210 | 206 | 202 | 197 | 194 | 190 | 186 | 182 | 179 | 175 | +| CED, GJ/h | -5 | -5 | -4 | -4 | -4 | -4 | -4 | -4 | -4 | -4 | -4 | -4 | -4 | -4 | -3 | -3 | + +Table 18 shows the hourly effect of lifetime extension for desktops. + +**Table 18 – Global effect per hour of reusing one desktop 5 extra years instead of just using the desktop 5 years, scenario B minus scenario A** + +| | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 | 2027 | 2028 | 2029 | 2030 | +|----------------------------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------| +| GWP, t CO 2 e/h | -0.45 | -0.44 | -0.43 | -0.43 | -0.42 | -0.41 | -0.40 | -0.39 | -0.39 | -0.38 | -0.37 | -0.36 | -0.36 | -0.35 | -0.34 | -0.33 | +| ADP, mg Sb-e/h | -237 | -232 | -227 | -223 | -218 | -214 | -210 | -206 | -202 | -197 | -194 | -190 | -186 | -182 | -179 | -237 | +| CED, GJ/h | -3.91 | -3.84 | -3.76 | -3.68 | -3.61 | -3.54 | -3.47 | -3.40 | -3.33 | -3.26 | -3.20 | -3.13 | -3.07 | -3.01 | -2.95 | -2.89 | + +Scenario B is 11% better than scenario A per hour for global warming potential at 100 years (GWP100). + +As shown in Table 17, emission of around 30-40 Mt CO2e can be avoided globally by reusing all desktops produced. Also per hour it is better to prolong the lifetime of the desktop as emission of 0.33 to 0.45 t CO2e and consumption of 2.89 to 3.91 GJ energy can be avoided (Table 18). + +### 8.2 Laptops + +Estimates of global shipments of laptops are listed in Table 19. + +**Table 19 – Estimated shipments of laptops 2015-2030 [b-Andrae]** + +| | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 | 2027 | 2028 | 2029 | 2030 | +|-------------------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------| +| Laptops, millions | 384 | 443 | 511 | 590 | 680 | 785 | 659 | 554 | 465 | 391 | 328 | 276 | 232 | 195 | 163 | 137 | + +In Table 20, 296 kg per laptop comes from roughly 300 cm2 PCB area (200 g CO2e/cm2), 30 cm silicon die area (4 000 g/cm2), 0.4 kg aluminium (16 kg/kg), 0.1 kg steel (4 kg/kg), 0.5 kg cables (8 kg/kg), 0.2 kg charger (10 kg/kg), 0.5 kg battery (60 kg/kg), 500 cm2 screen (45 g/cm2), 40 kg others. 275 kg in the use stage comes from 11.4 W, 8 760 h, 5 years and 0.55 kg CO2e/kWh. -31 kg CO2e/laptop is based on the material content and the circular footprint formulae [b-Wolf]. + +**Table 20 – Estimated GWP100 for average laptops** + +| Environmental impact category | Manufacturing | Use | End-of-life | +|-------------------------------|---------------|-----|-------------| +| GWP100, kg CO 2 e | 296 | 275 | -31 | + +Table 21 shows how the method explained in Table 2 is applied to laptops with Table 19 and Table 20. + +**Table 21 – Using Table 2 and Table 20 with Table 19** + +| | | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 | 2027 | 2028 | 2029 | 2030 | +|-----------------------------------------------------------------|-----------------------------------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------| +| Scenario A – One use of one laptop over 5 years | | | | | | | | | | | | | | | | | | +| 540 kg CO 2 e | GWP, Mt CO 2 e (total) | 207 | 239 | 276 | 318 | 367 | 424 | 356 | 299 | 251 | 211 | 177 | 149 | 125 | 105 | 88 | 74 | +| 0.012 3 kg CO 2 e | GWP, t CO 2 e/h | 4.7 | 5.5 | 6.3 | 7.3 | 8.4 | 9.7 | 8.1 | 6.8 | 5.7 | 4.8 | 4.0 | 3.4 | 2.9 | 2.4 | 2.0 | 1.7 | +| Scenario B – One laptop used twice over 10 years | | | | | | | | | | | | | | | | | | +| 815 kg CO 2 e | GWP, Mt CO 2 e (total) | 313 | 361 | 417 | 481 | 554 | 640 | 537 | 451 | 379 | 318 | 267 | 225 | 189 | 159 | 133 | 112 | +| 0.009 3 kg CO 2 e | GWP, t CO 2 e/h | 3.6 | 4.1 | 4.8 | 5.5 | 6.3 | 7.3 | 6.1 | 5.2 | 4.3 | 3.6 | 3.1 | 2.6 | 2.2 | 1.8 | 1.5 | 1.3 | +| Scenario C – Two laptops used 5 years each over 10 years | | | | | | | | | | | | | | | | | | +| 1 080 kg CO 2 e | GWP, Mt CO 2 e (total) | 415 | 478 | 552 | 637 | 735 | 847 | 712 | 598 | 502 | 422 | 354 | 298 | 250 | 210 | 176 | 148 | +| 0.012 3 kg CO 2 e | GWP, t CO 2 e/h | 4.7 | 5.5 | 6.3 | 7.3 | 8.4 | 9.7 | 8.1 | 6.8 | 5.7 | 4.8 | 4.0 | 3.4 | 2.9 | 2.4 | 2.0 | 1.7 | + +Table 22 shows scenario C minus scenario B for laptops. + +**Table 22 – Global effect of using two new laptop 10 years (scenario C) instead of one new laptop twice over 5 + 5 years, scenario C minus scenario B** + +| | | | | | | | | | | | | | | | | | +|-----------------------------------|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----| +| GWP, Mt CO 2 e (total) | 102 | 117 | 135 | 156 | 180 | 208 | 175 | 147 | 123 | 104 | 87 | 73 | 61 | 52 | 43 | 36 | +| GWP, t CO 2 e/h | 1.2 | 1.3 | 1.5 | 1.8 | 2.1 | 2.4 | 2.0 | 1.7 | 1.4 | 1.2 | 1.0 | 0.8 | 0.7 | 0.6 | 0.5 | 0.4 | + +Table 23 shows the hourly effect of lifetime extension for laptops. + +**Table 23 – Global effect per hour of reusing one laptop 5 extra years (after the 5 initial years) instead of just using the laptop 5 years once, scenario B minus scenario A** + +| | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 | 2027 | 2028 | 2029 | 2030 | +|----------------------------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------| +| GWP, t CO 2 e/h | -1.2 | -1.3 | -1.5 | -1.8 | -2.1 | -2.4 | -2.0 | -1.7 | -1.4 | -1.2 | -1.0 | -0.8 | -0.7 | -0.6 | -0.5 | -0.4 | + +Scenario B is 25% better than scenario A per hour for GWP100. + +As shown in Table 22, annually around emission of 40-100 Mt CO2e can be avoided globally by reusing all laptops produced. Also per hour it is better to prolong the lifetime of the laptops as emissions of 0.4 to 1.2 t CO2e can be avoided (Table 23). + +### 8.3 Modems (Wi-Fi) + +Estimates of global shipments of Wi-Fi modems are listed in Table 24. + +**Table 24 – Estimated shipments of modems (Wi-Fi) 2008-2015** + +| | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | +|-----------------------------------|------|------|------|------|--------------|------|------|------| +| Modems (WiFi), produced, millions | 250 | 275 | 300 | 315 | 315*1.05=331 | 347 | 365 | 383 | + +Assuming 5 years lifetime and 5% annual growth rate from 2011 to 2030 (Table 25), the numbers of Modems (Wi-Fi) in use at the same time become relatively reasonable. + +**Table 25 – Estimated shipments of modems (Wi-Fi) 2015-2030** + +| | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 | 2027 | 2028 | 2029 | 2030 | +|--------------------------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------| +| Modems (Wi-Fi), millions | 383 | 402 | 422 | 443 | 465 | 489 | 513 | 539 | 566 | 594 | 624 | 655 | 688 | 722 | 758 | 796 | + +For example, 1 471 million modems in use in 2012 comes from 250 + 275 + 300 + 315 + 331 = 1 471 million. As a result, perhaps around 2 000 million modems (Table 26) were in use in 2020 [b-Andrae]. + +**Table 26 – Estimated modems (Wi-Fi) in use 2012-2030** + +| | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 | 2027 | 2028 | 2029 | 2030 | +|---------------------------------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------| +| Modems (WiFi), in use, millions | 1 471 | 1 568 | 1 658 | 1 741 | 1 828 | 1 919 | 2 015 | 2 116 | 2 221 | 2 333 | 2 449 | 2 572 | 2 700 | 2 835 | 2 977 | 3 126 | 3 282 | 3 446 | 3 619 | + +Estimates of typical Wi-Fi modem life cycle GWP are listed in Table 27. + +**Table 27 – Estimated GWP100 for average modems (Wi-Fi)** + +| Environmental impact category | Manufacturing | Use | End-of-life | +|-------------------------------|---------------|-----|-------------| +| GWP100, kg CO 2 e | 27 | 89 | -0.03 | + +In Table 27, 29 kg per modem comes from roughly 340 cm2 PCB area (35 g CO2e/cm2), 4 g integrated circuits (1 600 g/g), 7 g aluminium (16 g/g), 0.8 g steel (4 g/g), 40 g cables (8 g/g), 8 kg others. 89 kg in the use stage comes from 3.7 W, 8 760 h, 5 years and 0.55 kg CO2e/kWh. + +NOTE – The modem is similar to the ONT in Table 11. + +**Table 28 – Using Table 2 and Table 25 with Table 27** + +| | | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 | 2027 | 2028 | 2029 | 2030 | +|------------------------------------------------------------------------|-----------------------------------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------| +| Scenario A – One use of one modem (Wi-Fi) over 5 years | | | | | | | | | | | | | | | | | | +| 115.97 kg CO 2 e | GWP, Mt CO 2 e (total) | 44 | 47 | 49 | 51 | 54 | 57 | 60 | 62 | 66 | 69 | 72 | 76 | 80 | 84 | 88 | 92 | +| 0.002 6 kg CO 2 e | GWP, t CO 2 e/h | 1.0 | 1.1 | 1.1 | 1.2 | 1.2 | 1.3 | 1.4 | 1.4 | 1.5 | 1.6 | 1.7 | 1.7 | 1.8 | 1.9 | 2.0 | 2.1 | +| Scenario B – One modem (Wi-Fi) used twice over 10 years | | | | | | | | | | | | | | | | | | +| 204.97 kg CO 2 e | GWP, Mt CO 2 e (total) | 78 | 82 | 87 | 91 | 95 | 100 | 105 | 110 | 116 | 122 | 128 | 134 | 141 | 148 | 155 | 163 | +| 0.002 33 kg CO 2 e | GWP, t CO 2 e/h | 0.9 | 0.9 | 1.0 | 1.0 | 1.1 | 1.1 | 1.2 | 1.3 | 1.3 | 1.4 | 1.5 | 1.5 | 1.6 | 1.7 | 1.8 | 1.9 | +| Scenario C – Two modem (Wi-Fi)s used 5 years each over 10 years | | | | | | | | | | | | | | | | | | +| 231.94 kg CO 2 e | GWP, Mt CO 2 e (total) | 89 | 93 | 98 | 103 | 108 | 113 | 119 | 125 | 131 | 138 | 145 | 152 | 159 | 167 | 176 | 185 | +| 0.002 6 kg CO 2 e | GWP, t CO 2 e/h | 1.0 | 1.1 | 1.1 | 1.2 | 1.2 | 1.3 | 1.4 | 1.4 | 1.5 | 1.6 | 1.7 | 1.7 | 1.8 | 1.9 | 2.0 | 2.1 | + +Table 29 shows scenario C minus scenario B for modems. + +**Table 29 – Global effect of using two new modems (Wi-Fi) 5 years each (scenario C) instead of one new modem (Wi-Fi) twice over 5 + 5 years, scenario C minus scenario B** + +| | | | | | | | | | | | | | | | | | +|-----------------------------------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------| +| GWP, Mt CO 2 e (total) | 10 | 11 | 11 | 12 | 13 | 13 | 14 | 15 | 15 | 16 | 17 | 18 | 19 | 19 | 20 | 21 | +| GWP, t CO 2 e/h | 0.12 | 0.12 | 0.13 | 0.14 | 0.14 | 0.15 | 0.16 | 0.17 | 0.17 | 0.18 | 0.19 | 0.20 | 0.21 | 0.22 | 0.23 | 0.25 | + +Table 30 shows the hourly effect of lifetime extension for modems. + +**Table 30 – Global effect per hour of reusing one modem (Wi-Fi) 5 extra years (after 5 initial years) instead of just using the modem (Wi-Fi) 5 years, scenario B minus scenario A** + +| | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 | 2027 | 2028 | 2029 | 2030 | +|----------------------------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------| +| GWP, t CO 2 e/h | -0.12 | -0.12 | -0.13 | -0.14 | -0.14 | -0.15 | -0.16 | -0.17 | -0.17 | -0.18 | -0.19 | -0.20 | -0.21 | -0.22 | -0.23 | -0.25 | + +Scenario B is 12% better than scenario A per hour for GWP100. + +As shown in Table 29, annually emissions of around 10-20 Mt CO2e can be avoided globally by reusing all modems (Wi-Fi) produced. Also, per hour it is better to prolong the lifetime of the modems (Wi-Fi) as 0.12 to 0.25 t of CO2e emissions can be avoided (Table 30). + +In summary, emissions of 80 to 160 Mt CO2e can be avoided by extending the lifetime of desktops, laptops and modems (Wi-Fi) by 5 years. This saving represents 0.25-0.5% of anthropogenic CO2e (34 Gt) emissions. + +## 9 Discussion + +The servitization model promotes the expansion of the operational lifespan of components and devices for as long as possible. This model spreads the manufacturing and end-of-life impacts over a longer usage period; however, not at the expense of the performance. The performance requirement for many uses may not need the latest performance provided by newer devices. These cases may present the largest untapped potential for refurbished products. A refurbished or remanufactured device may provide the required functionality. While in some scenarios the evolution of the performance and impact of devices changes significantly over a few years (technological obsolescence), other scenarios are more mature, with small improvements across generations. + +Reuse allows the identification and service of less demanding users and usage requirements with previous generation devices. This has been clearly seen in the COVID-19 crisis, where many schoolchildren benefit for home schooling from second-hand computers decommissioned from public and private offices. + +There are potentially several trade-offs between use stage energy, closed-loop waste management, and software upgrade driven obsolescence that could be investigated further. The role of machine learning is also not understood well enough in the present context. + +It seems like environmental benefits are much more evident for impact categories (e.g., ADP) more sensitive to environmental impacts during manufacturing and categories that are almost independent of electricity consumption during operation. + +Direct reuse is often more environmentally friendly than reuse of some parts followed by reuse. + +In the future, standardization on batteries may be important, e.g., in calculation methods for environmental reuse benefits. + +## Bibliography + +- [b-ITU-T L.Suppl.28] ITU-T L-series Recommendations – Supplement 28 (2016), *Circular economy in information and communication technology; Definition of approaches, concepts and metrics*. +- [b-ITU-T L.Suppl.32] ITU-T L-series Recommendations – Supplement 32 (2016), *Supplement for eco-specifications and rating criteria for mobile phones eco-rating programmes*. +- [b-EN 45554] EN 45554:2020, *General methods for the assessment of the ability to repair, reuse and upgrade energy-related products*. +- [b-Andrae] Andrae, A.S.G. (2020): New perspectives on internet electricity use in 2030. *Eng. Appl. Sci. Lett.* **3**(2), pp. 19-31. +- [b-André] André, H., Ljunngren-Söderman, M., Nordelöf, A. (2019). Resource and environmental impacts of using second-hand laptop computers: A case study of commercial reuse. *Waste Manag.* **88**, pp. 268-279. DOI: [10.1016/j.wasman.2019.03.050](https://doi.org/10.1016/j.wasman.2019.03.050) +- [b-Ardente] Ardente, F., Peiró, L. T., Mathieux, F., Polverini, D. (2018). Accounting for the environmental benefits of remanufactured products: Method and application. *J. Clean. Prod.* **198**, pp. 1545-1558. Available [viewed 2021-03-02] at: +- [b-Barroso] Barroso, L.A., Hölzle, U. (2007). The case for energy-proportional computing. *Computer.* **40**(12), pp. 33–37. DOI: [10.1109/mc.2007.443](https://doi.org/10.1109/mc.2007.443). +- [b-Boyd] Boyd, S., Horvath, A., D. Dornfeld, D. (2011). Life-cycle assessment of NAND flash memory. In: *IEEE Trans. Semiconductor Manufacturing*, **24**(1), pp. 117-124. DOI: [10.1109/TSM.2010.2087395](https://doi.org/10.1109/TSM.2010.2087395) +- [b-Franquesa 2018] Franquesa, D., Navarro, L. (2018). Devices as a commons: Limits to premature recycling. In: *Proc. Fourth Workshop on Computing within Limits (Limits'18)*, June 2018, Article 8, 10 pp. New York, NY; ACM. DOI: [10.1145/3232617.3232624](https://doi.org/10.1145/3232617.3232624) +- [b-Franquesa 2019] Franquesa, D., Navarro, L., Fortelny, S., Roura, M., Nadeu J. (2019). Circular consumption and production of electronic devices: An approach to measuring durability, upgradeability, reusability, obsolescence and premature recycling. Paper presented at: *The European Roundtable for Sustainable Consumption and Production – Circular Europe for Sustainability*, Barcelona. Available [viewed 2021-03-02] at: +- [b-Franquesa 2020] Franquesa, D., Roura, M., Navarro, L., (2020). Exploring life-cycle data of devices for measuring durability. eReuse project. Available [viewed 2021-03-02] at: [https://dsg.ac.upc.edu/sites/default/files/dsg/eReuseDataJun2019\\_0.html](https://dsg.ac.upc.edu/sites/default/files/dsg/eReuseDataJun2019_0.html) +- [b-Goldey] Goldey, C. L., Kuester, E. U., Mummert, R., Okrasinski, T. A., Olson, D., Schaeffer, W. J. (2010). Lifecycle assessment of the environmental benefits of remanufactured telecommunications product within a "green" supply chain. In: *Proc. 2010 IEEE Int. Symp. on Sustainable Systems and Technology*, Arlington, VA, pp. 1-6. New York, NY: IEEE. DOI: [10.1109/ISSST.2010.5507761](https://doi.org/10.1109/ISSST.2010.5507761) +- [b-Kowalkowski] Kowalkowski, C., Gebauer, H., Kamp, B., Parry, G. (2017). Servitization and deservitization: Overview, concepts, and definitions. *Indust. Market. Manag.* **60**, pp. 4-10. DOI: [10.1016/j.indmarman.2016.12.007](https://doi.org/10.1016/j.indmarman.2016.12.007) + +- [b-Song] Song, Q.B., Wang, Z.S., Li, J.H., Yuan, W.Y. (2013). Life cycle assessment of desktop PCs in Macau. *Int. J. Life Cycle Assess.* **18**, pp. 553-566. DOI: 10.1007/s11367-012-0515-7 +- [b-Tasaki] Tasaki, T., Motoshita, M., Uchida, H., Suzuki, Y. (2013). Assessing the replacement of electrical home appliances for the environment: An aid to consumer decision making. *J. Indust. Ecol.* **17**(2), pp. 290-298. DOI: [10.1111/j.1530-9290.2012.00551.x](https://doi.org/10.1111/j.1530-9290.2012.00551.x) +- [b-Vaija] Vaija, M.S, Philipot, E. (2018). Multiple facets of circular economy applied to telecommunications operator's activities. In: *Going Green – Care Innovation*, 2018-11-26/29, Vienna. Abstract available [viewed 2021-03-02] in [http://www.4980.timewarp.at/CARE/CI2018/PDFs/Program%20%20Abstracts%20CARE%20INNOVATION%202018\\_26112018.pdf](http://www.4980.timewarp.at/CARE/CI2018/PDFs/Program%20%20Abstracts%20CARE%20INNOVATION%202018_26112018.pdf) +- [b-van Oers] van Oers, L., de Koning, A., Guinée, J.B., Huppes G (2002). *Abiotic resource depletion in LCA – Improving characterisation factors for abiotic resource depletion as recommended in the new Dutch LCA handbook*. RWS-DWW report. Delft: Road and Hydraulic Engineering Institute. 75 pp. Available [viewed 2020-03-02] at: [http://www.leidenuniv.nl/cml/ssp/projects/lca2/report\\_abiotic\\_depletion\\_web.pdf](http://www.leidenuniv.nl/cml/ssp/projects/lca2/report_abiotic_depletion_web.pdf) +- [b-Wolf] Wolf, M.-A., De Schryver, A., Hofstra, U., Zampori, L., Vroege, G.-J., Wolf, K. (2019). *Circular footprint formula – Webinar; Environmental footprint (EF) transition phase*. Brussels: European Commission. 37 pp. Available [viewed 2021-03-02] at: [https://ec.europa.eu/environment/eussd/pdf/Webinar%20CFF%20Circular%20Footprint%20Formula\\_final-shown\\_8Oct2019.pdf](https://ec.europa.eu/environment/eussd/pdf/Webinar%20CFF%20Circular%20Footprint%20Formula_final-shown_8Oct2019.pdf) + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over 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other elements of outside plant + +E-waste and circular economy + +--- + +## **Circular public procurement of information and communication technologies** + +![ITU logo](0538daaa5583c23e17db3a12f2281a55_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with white grid lines and a stylized 'ITU' text in blue, with a white lightning bolt symbol integrated into the letter 'I'. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +## ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT + +| | | +|--------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node elements (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000–L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200–L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300–L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400–L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500–L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600–L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700–L.1799 | + +For further details, please refer to the list of ITU-T Recommendations. + +# Recommendation ITU-T L.1061 + +# Circular public procurement of information and communication technologies + +## Summary + +Green procurement policies, which focus on purchasing durable information and communication technology (ICT) equipment and recycling e-waste, can help reduce emissions and resource extractions and influence the market by increasing demand and stimulating research and product development. + +Recommendation ITU-T L.1061 provides technical guidance to public sector organizations on improving their procurement practices to purchase more circular ICT goods and services. The Recommendation covers the purchase of ICT equipment such as personal computers, terminals, network equipment and servers, and imaging equipment, and recommends specific requirements in procurement to (1) minimize the generation of e-waste and its adverse effects; (2) maximize the use of energy-efficient equipment; (3) maximize the useful life of equipment; and (4) maximize recyclability. It also covers design for e-waste prevention and procurement recommendations which are relevant for the management choices of the e-waste hierarchy, as well as specific requirements and guidance on procurement to enhance the energy efficiency, reduce greenhouse gas (GHG) emissions to mitigate climate change and reduce the emissions of hazardous substances in e-waste. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|--------------------------------------------------------------------------------------------| +| 1.0 | ITU-T L.1061 | 2023-03-28 | 5 | 11.1002/1000/15469 | + +## Keywords + +Circular economy, e-waste, green, ICTs, public procurement, recyclability. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2023 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|------|-------------------------------------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 3 | +| 3.1 | Terms defined elsewhere ..... | 3 | +| 3.2 | Terms defined in this Recommendation ..... | 4 | +| 4 | Abbreviations and acronyms ..... | 4 | +| 5 | Conventions ..... | 5 | +| 6 | Environmental and circular aspects of public procurement of ICTs..... | 5 | +| 6.1 | General principles and considerations for green public procurement..... | 5 | +| 6.2 | Methods for calculating cost in public procurement..... | 6 | +| 6.3 | Phases of the tendering process ..... | 6 | +| 6.4 | Models of ownership..... | 8 | +| 6.5 | Verification ..... | 8 | +| 7 | The e-waste hierarchy ..... | 8 | +| 8 | Minimization of the generation of e-waste and its adverse effects ..... | 9 | +| 8.1 | Policy..... | 9 | +| 8.2 | Materials..... | 10 | +| 8.3 | Product design ..... | 11 | +| 8.4 | Needs assessment ..... | 11 | +| 8.5 | Interoperability and reusability of components ..... | 12 | +| 8.6 | Transparency, reporting ..... | 12 | +| 8.7 | Procurement process ..... | 12 | +| 8.8 | Traceability ..... | 13 | +| 8.9 | Consumables..... | 13 | +| 8.10 | Batteries..... | 14 | +| 9 | Maximizing useful life ..... | 14 | +| 9.1 | Stress during usage..... | 14 | +| 9.2 | Management..... | 15 | +| 9.3 | Maintenance and repair ..... | 16 | +| 9.4 | Usage..... | 17 | +| 9.5 | Secondary usage (reuse)..... | 18 | +| 9.6 | Energy consumption and energy efficiency in the use phase..... | 19 | +| 9.7 | Procurement of refurbished and remanufactured products..... | 19 | +| 9.8 | Batteries..... | 20 | +| 10 | Maximizing recyclability ..... | 21 | +| 11 | Summary of requirements..... | 22 | +| | Bibliography ..... | 26 | + +## Introduction + +Communities worldwide face the consequences of climate change, depletion of natural resources, loss of biodiversity, environmental degradation and increasing poverty [b-UNDP]. To address these issues, all levels of society (public and private) realize that change is required to develop a more sustainable society and planet. Sustainable development [b-UN-1] has three pillars: economic, social and environmental. + +Over their lifespan, ICT products follow pre-use, use and post-use processes. Raw material and part production, design and ICT goods manufacturing are pre-use processes that result in an ICT product. Procurement is the first process in an expected long use phase of that product, followed by post-use end-of-life treatment that starts with collecting ICT products declared as e-waste. Each decision in a given process affects the following decision. Pre-use decisions determine the durability of a product in the use phase. In the end, the amount of resulting e-waste, its effects and recyclability are also affected by pre-use decisions, but procurement is the first and key use decision. + +Purchasing durable ICT equipment and recycling e-waste helps reduce emissions and resource extraction. Furthermore, green procurement policies can influence the market by increasing demand and stimulating research and product development, thus leading to increased availability and better prices for these ICT products. + +This Recommendation focuses on the environmental pillar of sustainability in the public procurement of ICT products. Therefore, it aims to provide a set of circular procurement principles to contribute to achieving environmental goals for organizations in [ITU-T L.1420], the Connect 2030 in [ITU-T L.1031] for the ICT sector, and the planetary goals of the UNFCCC starting with the Paris Agreement. + +Sustainable public procurement aims at achieving the best value for money on a whole-life basis in terms of generating benefits not only to the organization but also to society and the economy while minimizing environmental damage [b-DEFRA]. Cost, environmental and social aspects are the main components. + +This Recommendation is structured as follows: + +- The framework of environmental and circularity considerations in the public procurement of ICT products and services is in clause 6. +- The e-waste hierarchy ranks environmentally sound e-waste management strategies in clause 7. +- How procuring ICT equipment can contribute to minimizing the amount of e-waste produced at the top of the waste hierarchy, preventing its adverse effects on human health and the environment in clause 8. +- Extension of a product's lifetime in clause 9. +- Increasing recyclability contributes to the circular economy in clause 10. +- A summary of recommendations grouped by broad ICT product categories in clause 11. + +To facilitate the implementation of the Recommendation, The Circular and Sustainable Public Procurement Guide [b-ITU23] provides practical guidance and help to ICT procurement planners and professionals to improve the circular and sustainable outcomes of their organization's ICT buying decisions and to avoid adverse impacts on social and environmental systems. The guide was developed in parallel with this Recommendation. Three levels of circular and sustainable ICT procurement for getting started or improving the level of circular and sustainable ICT procurement are covered in the guide: + +- 1) Policy and strategy, including setting the guiding principles and goals and planning for circular and sustainable ICT procurement. +- 2) Creating the conditions, covering the practical steps for capacity building, target setting and enabling circular and sustainable ICT procurement. + +- 3) Procurement processes, providing methods, approaches and cases of application for circular and sustainable procurement of ICT on the ground. + +While predominately aimed at national governments, the guide is equally applicable to other public buyers. The guide has been developed by the GovStack initiative in collaboration with the Circular Electronics Partnership. + + + +# Recommendation ITU-T L.1061 + +## Circular public procurement of information and communication technologies + +## 1 Scope + +This Recommendation provides a set of principles that provides a basis for circular public procurement of ICT equipment to: + +- Maximize usable life, +- Maximize the use of energy-efficient equipment, +- Minimize any resulting amount of e-waste produced, and the adverse effects of e-waste, and +- Increase recyclability, thereby contributing to circular economy realization. + +This set of recommendations defines standards to help the public sector in deciding the ICT products to be procured that will not only be cost-effective but also to minimize e-waste during and after a product's end of use. It means purchase preference shall be given to those products that are environmentally sustainable and that already contain sustainability as a criterion. The decisions of the public sector shall reward the manufacturers of ICT products to move towards more environmentally sustainable ICT products in the medium to long term. + +This Recommendation covers the purchase of ICT equipment and including: + +- Personal computer (PC) products including desktops, laptops, servers, displays, docks and other accessories. +- Terminals, such as smartphones, tablets and video-conferencing devices. +- Network equipment and servers including network switches, routers, Wi-Fi access points and network adapters. +- Imaging equipment, such as scanners and printers. + +In general, any ICT equipment acquired through public procurement is at the procurer organization's disposal for use. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T L.1000] Recommendation ITU-T L.1000 (2019), *Universal power adapter and charger solution for mobile terminals and other hand-held ICT devices*. +- [ITU-T L.1001] Recommendation ITU-T L.1001 (2012), *External universal power adapter solutions for stationary information and communication technology devices*. +- [ITU-T L.1002] Recommendation ITU-T L.1002 (2016), *External universal power adapter solutions for portable information and communication technology devices*. +- [ITU-T L.1005] Recommendation ITU-T L.1005 (2014), *Test suites for assessment of the universal charger solution*. + +- [ITU-T L.1010] Recommendation ITU-T L.1010 (2014), *Green battery solutions for mobile phones and other hand-held information and communication technology devices.* +- [ITU-T L.1021] Recommendation ITU-T L.1021 (2018), *Extended producer responsibility - Guidelines for sustainable e-waste management.* +- [ITU-T L.1022] Recommendation ITU-T L.1022 (2019), *Circular economy: Definitions and concepts for material efficiency for information and communication technology.* +- [ITU-T L.1023] Recommendation ITU-T L.1023 (2020), *Assessment method for circular scoring.* +- [ITU-T L.1024] Recommendation ITU-T L.1024 (2021), *The potential impact of selling services instead of equipment on waste creation and the environment – Effects on global information and communication technology.* +- [ITU-T L.1031] Recommendation ITU-T L.1031 (2020), *Guideline for achieving the e-waste targets of the Connect 2030 Agenda.* +- [ITU-T L.1033] Recommendation ITU-T L.1033 (2021), *Guidance for institutions of higher learning to contribute in the effective life cycle management of e-equipment and e-waste.* +- [ITU-T L.1035] Recommendation ITU-T L.1035 (2022), *Sustainable management of batteries.* +- [ITU-T L.1220] Recommendation ITU-T L.1220 (2017), *Innovative energy storage technology for stationary use – Part 1: Overview of energy storage.* +- [ITU-T L.1221] Recommendation ITU-T L.1221 (2018), *Innovative energy storage technology for stationary use - Part 2: Battery.* +- [ITU-T L.1300] Recommendation ITU-T L.1300 (2014), *Best practices for green data centres.* +- [ITU-T L.1301] Recommendation ITU-T L.1301 (2015), *Minimum data set and communication interface requirements for data centre energy management.* +- [ITU-T L.1304] Recommendation ITU-T L.1304 (2020), *Procurement criteria for sustainable data centres.* +- [ITU-T L.1310] Recommendation ITU-T L.1310 (2020), *Energy efficiency metrics and measurement methods for telecommunication equipment.* +- [ITU-T L.1320] Recommendation ITU-T L.1320 (2014), *Energy efficiency metrics and measurement for power and cooling equipment for telecommunications and data centres.* +- [ITU-T L.1321] Recommendation ITU-T L.1321 (2015), *Reference operational model and interface for improving energy efficiency of ICT network hosts.* +- [ITU-T L.1330] Recommendation ITU-T L.1330 (2015), *Energy efficiency measurement and metrics for telecommunication networks.* +- [ITU-T L.1340] Recommendation ITU-T L.1340 (2014), *Informative values on the energy efficiency of telecommunication equipment.* +- [ITU-T L.1410] Recommendation ITU-T L.1410 (2014), *Methodology for environmental life cycle assessments of information and communication technology goods, networks and services.* + +- [ITU-T L.1420] Recommendation ITU-T L.1420 (2012), *Methodology for energy consumption and greenhouse gas emissions impact assessment of information and communication technologies in organizations*. +- [ITU-T L.1470] Recommendation ITU-T L.1470 (2020), *Greenhouse gas emissions trajectories for the information and communication technology sector compatible with the UNFCCC Paris Agreement*. +- [IEC 62623] IEC 62623:2022 (2022), *Desktop and notebook computers – Measurement of energy consumption*. + +## 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 environmental life cycle assessment** [ITU-T L.1410]: An environmental life cycle assessment (LCA) is a systematic analytical method by which the potential environmental effects related to ICT goods, networks and services .... can be estimated. LCAs have a cradle-to-grave scope where all the life cycle stages (raw material acquisition, production, use, and end-of-life treatment) are included. Moreover, transport and energy supplies are included at each stage of the life cycle assessment. + +**3.1.2 green public procurement** [b-EU-1]: A process whereby public authorities seek to procure goods, services and works with a reduced environmental impact throughout their life cycle when compared to goods, services and works with the same primary function that would otherwise be procured. + +**3.1.3 life cycle** [b-ISO 14040]: Consecutive and interlinked stages of a product system, from raw material acquisition or generation from natural resources to final disposal. + +**3.1.4 life cycle costing** [b-ICLEI]: A method for assessing the total costs of the product group or service under study. It takes into account all costs related to the purchase and use of and maintenance operations for this product group or service and the disposal of any waste generated by it. + +**3.1.5 needs assessment** [b-EC-2]: The first stage in the procurement cycle for green public procurement, prior to launching a tender, to ensure that a true demand exists for the goods, services or works being purchased, and to identify the most environmentally efficient way of meeting that need. + +**3.1.6 public procurement for innovation** [b-OECD17]: This happens when the public sector uses its purchasing power to act as early adopter of innovative solutions which are not yet available on large scale commercial basis. + +**3.1.7 recyclability** [ITU-T L.1022]: Ability of a product to be recycled at end-of-life. + +**3.1.8 refurbishing** [b-IEV-904-04-09]: Functional or aesthetical maintenance or repair of an item to restore to original, upgraded, or other predetermined form and functionality. + +**3.1.9 remanufacturing** [b-EN 4553]: Industrial process which produces a product from used products or used parts where at least one change is made which influences the safety, original performance, purpose or type of the product. + +**3.1.10 supply chain** [b-ITU-2]: The group of planning, manufacturing and producing operations required to bring a product/service to the market. It covers activities that range from sourcing of raw materials to the delivery of a completed product. + +**3.1.11 supply chain due diligence** [b-EC-3]: The obligations of the economic operator which places a [product] on the market, in relation to its management system, risk management, third party verifications by notified bodies and disclosure of information with a view to identifying and addressing actual and potential risks linked to the sourcing, processing and trading of the raw materials required for [product] manufacturing. + +**3.1.12 sustainable public procurement** [b-DEFRA]: A process whereby organizations meet their needs for goods, services, works and utilities in a way that achieves value for money on a whole-life basis in terms of generating benefits not only to the organization, but also to society and the economy, whilst minimizing damage to the environment. + +**3.1.13 total cost of ownership** [b-Mieritz]: A financial estimate intended to help buyers and owners determine the direct and indirect costs of a product or system. It is a management accounting concept that can be used in cost accounting, strategic planning and budgeting. + +**3.1.14 tracing** [b-Dorp]: The ability to follow the supply chain upward and determine the source of a product. + +**3.1.15 tracking** [b-Dorp]: The ability of keeping track of the flows of products transporting from upstream to downstream in a supply chain. + +**3.1.16 waste hierarchy** [ITU-T L.1031]: Preference for actions in managing waste, including e-waste in five tiers of decreasing preference: waste prevention, preparation for re-use, recycling, other recovery and disposal. + +### **3.2 Terms defined in this Recommendation** + +This Recommendation defines the following terms: + +**3.2.1 public sector:** All levels of government and government-controlled or funded agencies, enterprises and other organizations that deliver public programmes, goods or services. + +**3.2.2 circular and sustainable procurement:** The purchase of goods, services, works and utilities that meets user needs while generating positive environmental and societal impacts and stimulating the circular economy through purposeful design, production, sale, use, re-use and recycling processes throughout the lifecycle. + +**3.2.3 state of health:** Current full charge battery capacity (in mAh) expressed as a percentage of the design capacity (rated capacity). + +## **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|-----------------------------------| +| AC | Award Criteria | +| AMC | Annual Maintenance Contract | +| BBP | Butyl Benzyl Phthalate | +| CFC | Chlorofluorocarbon | +| CPE | Customer Premises Equipment | +| CPC | Contract Performance Clause | +| CPU | Central Processing Unit | +| DBP | Dibutyl Phthalate | +| DEHP | Bis(2-ethylhexyl) Phthalates | +| DIBP | Diisobutyl Phthalate | +| EPD | Environmental Product Declaration | +| EPR | Extended Producer Responsibility | +| GHG | Greenhouse Gas | +| GPP | Green Public Procurement | + +| | | +|-------|----------------------------------------------------------------------| +| GWP | Global Warming Potential | +| HCFC | Hydrochlorofluorocarbon | +| HFC | Hydrofluorocarbon | +| IMA | Imaging | +| LCA | Lifecycle Assessment | +| LCC | Lifecycle Cost Analysis | +| MON | Monitors | +| MOB | Mobile/Battery-Powered Computers | +| NIE | Network Infrastructure Equipment | +| OEM | Original Equipment Manufacturer | +| PBB | Polybrominated Biphenyl | +| PBDE | Polybrominated Biphenyl Ether | +| PCC | Post-Consumer Recycled Content | +| RAM | Random Access Memory | +| REACH | Registration, Evaluation, Authorization and Restriction of Chemicals | +| ROHS | Restriction of Hazardous Substances | +| RSC | Restricted Substance Controls | +| SC | Selection Criteria | +| STD | Standard | +| STA | Stationary Computers, Terminals, Network Devices | +| TCO | Total Cost of Ownership | +| TS | Technical Specification | +| WEEE | Waste Electrical and Electronic Equipment | + +## 5 Conventions + +None. + +## 6 Environmental and circular aspects of public procurement of ICTs + +### 6.1 General principles and considerations for green public procurement + +- Buying responsibly and sustainably: Public administrations/public sector can have an impact in addressing these issues through the implementation of eco-friendly procurement practices without undermining cost-efficiency. The good news is that procurement costs can be reduced by purchasing products that are less harmful to the environment. +- Environmental impacts: that stem from their manufacturing, use and disposal. +- Manufacturing activities include acquiring, assembling and transporting raw materials and components. The supply chain in the ICT industry is highly complex, as ICT products can be made of several thousands of components made up of a large variety of materials and substances. + +- Energy consumption and carbon emissions: ICT equipment requires electricity to run, including power used directly and indirectly power use such as for cooling in data centres or maintenance operations. +- Water is used to manufacture ICT products and for data centre cooling operations. +- Noise is generated by motors and spinning components, such as hard drive, CPU fan, case cooling fan and power supply fan [b-EU-2]. +- Hazardous materials: Electrical and electronic equipment can contain various substances harmful to health and the environment if not manufactured, used and disposed of carefully. +- End-of-life disposal, recycling and durability. Though some components cannot be reused, much of what is used to make ICT equipment can be recycled, even though electronics recycling can be challenging because discarded electronic products are complex devices, and the amount of resources recovered may be small. +- Packaging materials are generated at various stages of the ICT lifecycle to transport, protect and distribute products. +- Fostering compliance with open standards and interoperable systems compatible with as many equipment manufacturers as possible. + +### 6.2 Methods for calculating cost in public procurement + +Public procurement is usually driven by the concept of the best value for money [b-UNOPS], considering only the purchase cost, ignoring the life cycle cost or non-financial impacts from a life cycle assessment: + +- Life cycle cost (LCC) is the name of the technique used to establish the actual cost of ownership of a product or service, from purchase, through usage and maintenance costs, to disposal. That is the cost to consider as it incorporates other costs, otherwise hidden, beyond the purchase cost. The reduction of environmental impacts usually leads to economic savings in short to medium-term term [b-UNOPS]. From a procurement perspective, total cost of ownership (TCO) refers to the overall sum of all costs. LCC is one method available to calculate this TCO. +- Life cycle assessment (LCA) applies the life cycle concept to environmental impacts, such as carbon emissions, water usage, air pollution, energy consumption, hazardous and toxic substances and waste amounts [b-UNOPS]. This is standardized in [ISO 14040] and applied to evaluate the environmental impact of ICT goods, networks and services in [ITU-T L.1410]. + +In environmental or green public procurement (GPP), the preferred procurement choice must be products and services with a positive environmental impact. + +These products may include, according to [b-UNDP], green features at the expense of additional cost or resource consumption, such as products that are energy-efficient, with reduced environmental impact of the production phase, that contain less toxic materials, have a longer life cycle, that can be recycled, that minimize or eliminate packaging, minimize the use of natural resources, that are made from recycled materials, that can be easily repaired, maintained or upgraded, and whose firmware and software can be updated for a long period. These types of products are designed with the goal of reducing their environmental impact throughout their entire life cycle, from production to disposal. These features are described in detail in [b-ITU-T L.Suppl 20]. + +### 6.3 Phases of the tendering process + +All that relates to the vision of the Circular and Fair ICT Pact [b-One Planet Network] to accelerate the transition to a sustainable ICT sector by taking a strategic approach to procurement, considering the three phases of the tendering process: + +- The **pre-tender** phase of **buying less** involves setting ambitions, identifying needs and market collaboration. +- The **tender** phase of **buying better** by designing specifications and tender, followed by evaluation and award. +- The **post-tender** phase of **using better and longer** by managing supply, contract management and asset disposal. + +The pre-tender relates to the first aim, the tender phase relates to all aims and the post-tender refers to the first two aims. + +Four main types of GPP criteria [b-Kaps] apply in the previous three phases: + +- **Selection criteria (SC):** Assess the suitability of an economic operator, a tenderer, to carry out a contract (such as capacity to pursue activity, economic and financial standing, technical and professional ability). +- **Technical specifications (TS):** The required characteristics of a product or a service, including requirements relevant to the product at any stage of the life cycle of the supply or service and conformity assessment procedures. +- **Award criteria (AC):** Qualitative criteria with a weighted scoring are chosen to determine the most economically advantageous tender. Specifically, environmental performance characteristics to take into account. +- **Contract performance clauses (CPC):** Special conditions laid down that relate to the performance of a contract and how it must be carried out and monitored, provided that they are linked to the subject matter of the contract (such as reporting on environmental performance, impact during product usage, lifespan or recycling). + +There is a choice between two ambition levels for the criteria: + +- **Core criteria** for easy application of GPP, focussing on key areas of the environmental performance of a product and aimed at keeping administrative costs for companies to a minimum. +- **Comprehensive criteria**, considering more aspects or higher levels of environmental performance, to go further in supporting environmental and innovation goals. This can be more challenging and costly to implement, as it requires a more thorough evaluation of the environmental impacts of the products being procured. However, it can also bring long-term benefits. By setting higher standards for environmental performance, comprehensive criteria can encourage the development and use of more environmentally friendly products, which can lead to reduced environmental impacts and costs over the product's lifecycle. In addition, it can help to drive innovation and support the development of new technologies that can contribute to the transition to a more sustainable and circular economy. + +The pre-tender phase can benefit from assessing the existing fleet and procurement needs related to a CPC. Choices in the tender phase affect the post-tender phase, particularly CPC, regarding servicing, consumables and reporting. + +Environmentally conscious design, or design-for-environment (DfE) [b-ITU-1], *namely the systematic integration of environmental considerations into product and process design* is relevant here. [ITU-T L.1031] highlights the four-key lifecycle phases of network infrastructure equipment (NIE) and customer premises equipment (CPE) and how each stage can be more sustainable. The four phases are: + +- environmentally conscious product development, +- eco-efficient manufacturing, +- smart usage, +- end-of-life treatment. + +The first phase relates to all aims, and the remaining phases match each of the three aims. + +### 6.4 Models of ownership + +There are alternative models to ownership, as organizations need ICT devices for the services they provide, not for the sake of ownership. Therefore, innovative service-oriented circular models focused on usage may allow more efficient management of devices and less e-waste generation than those oriented to ownership [ITU-T L.1024]. Decoupling ownership from use and maintenance involves other schemes such as **servitization** (use as a service provided by a third-party) or **pooling** and leasing devices across larger user groups (shared ownership). + +Other circular business models are: + +- Buy refurbished or remanufactured (use longer). +- Buy service: servitization or leasing, including external maintenance and support (use longer). +- Buy less: analyse concrete demand. +- Disposal of used products: Ensure products are adequately collected and with accessories [b-CFIP] and recycled properly (less waste). + +### 6.5 Verification + +The means of compliance **verification** for a product with a necessary or desirable green or circular characteristic can come from a declaration of the tenderer documenting the claim or holding a relevant Type I Ecolabel fulfilling the specified characteristic. + +As a general compliance verification criterion, [b-Alfieri] proposes that products holding a relevant Type I Ecolabel [b-ISO 14024] or a label from another labelling scheme fulfilling the specified requirements will be deemed to comply. Alternative test results obtained by test bodies accredited in line with [b-ISO 17025] according to specific product categories, such as [b-ISO 14006] considering ecodesign in general, [b-IEC 62474] for electronic products and [b-IEEE 1680.1] for assessing the environmental performance of PC products, may be accepted as proof of compliance. + +The complexity introduced by GPP can be tamed by coordination such as: + +- Buyers' groups; +- International networks; +- Common criteria and guidance; + +That coordination facilitates that procurers can: + +- Procure circularly and fairly; +- Have the capacity to dialogue with the market (joint with international suppliers); +- Benefit from knowledge sharing with other similar organizations. + +## 7 The e-waste hierarchy + +As defined and standardized by [ITU-T L.1031], the best strategies for the environmentally sound management of e-waste are ranked in the waste management hierarchy, from waste prevention and minimization, and waste recycling to the final disposal. A visual representation is shown in Figure 1. + +![Figure 1 – The waste hierarchy [ITU-T L.1031]. A blue inverted triangle divided into five horizontal segments. From top to bottom, the segments are labeled: Waste prevention, Preparing for Re-use, Recycling, Other recovery, and Disposal. The top segment is the largest, and the bottom segment is the smallest.](8fbdfc3d17fb1dae7b2d8f5a287fa9fc_img.jpg) + +Figure 1 – The waste hierarchy [ITU-T L.1031]. A blue inverted triangle divided into five horizontal segments. From top to bottom, the segments are labeled: Waste prevention, Preparing for Re-use, Recycling, Other recovery, and Disposal. The top segment is the largest, and the bottom segment is the smallest. + +L.1061(23) + +**Figure 1 – The waste hierarchy [ITU-T L.1031]** + +According to the Basel Convention, guidance on strategies for preventing and minimizing hazardous and other wastes, prevention may include strict avoidance, source reduction and direct reuse [b-UNEP-2]. The following clauses recommend, in light of the e-waste hierarchy, the principles to be taken into consideration in the public procurement processes including: minimization of e-waste; optimization of use; and maximization of recyclability. + +## **8 Minimization of the generation of e-waste and its adverse effects** + +On top of the waste hierarchy, minimizing the amount of e-waste generated and its hazardousness (toxicity) is the most effective strategy. E-waste prevention is the first pillar of e-waste minimization. This is related to the e-waste prevention targets of the Connect 2030 Agenda [ITU-T L.1031]. Targeting the reduction of e-waste generation has several implications: + +- Reduction by the design of the **quantity of material** used in the manufacturing of products; +- Designing products with lower **toxicity in materials and compounds**; +- Consider procuring products that are not only new but also refurbished or remanufactured (developed in the next clauses); +- Consider using or consuming products for longer, encouraging the extension of a product's lifetime, ensuring any preventive maintenance, repair when faulty, and seeking reuse when no longer used (developed in the next clause); +- Keeping track of products to keep them accountable (traceable) and facilitate recycling (last clause). + +### **8.1 Policy** + +Governments need to define organizational, governmental or national targets for circular public procurement. + +It is necessary to incorporate in GPP processes organizational, governmental or national targets for e-waste reduction policy or objectives set according to [ITU-T L.1470] on GHG emissions for ICT compatible with the UNFCCC Paris Agreement or according to [ITU-T L.1031] on Guideline for achieving the e-waste targets of the Connect 2030 in [ITU-T L.1031] or as an input to an organizational impact assessment according to [ITU-T L.1420]. + +It is necessary to assess the environmental impacts of the procurement of ICT devices and ask for waste neutrality or waste compensation in specifications or award criteria. The expected outcome will be that suppliers make sure an equivalent amount of e-waste is collected and recycled. + +As **SC** and **CPCs** collect environmental impact indicators from procured goods and services over the four-key lifecycle phases [ITU-T L.1031], it is necessary to facilitate the accounting of organizational environmental/sustainability impacts. + +### 8.2 Materials + +It is needed to verify restrictions on hazardous substances in products and parts. That includes the following: + +The European Directive on the "restriction of the use of certain hazardous substances in electrical and electronic equipment" (ROHS) [b-EU-6] restricts the use of certain hazardous chemicals in products in the European Union. This policy is also implemented in other states. In particular, ROHS refers to the guidelines regulating the use of hazardous chemicals in electrical and electronic equipment (EEE). As a result, a list of hazardous chemicals is forbidden above a threshold due to their toxicity or environmental hazard. Currently, 10 substances are restricted due to their toxicity or environmental hazard: + +- Lead +- Mercury +- Cadmium +- Hexavalent chromium +- PBDEs (polybrominated biphenyl ethers) +- PBBs (polybrominated biphenyls) +- DBP (Dibutyl phthalate) +- DIBP (Diisobutyl phthalate) +- BBPs (Butyl benzyl phthalates) +- DEHPs (Bis(2-ethylhexyl) phthalates) + +The use above the thresholds is still allowed for some applications where no alternatives are available. The exemptions are reviewed by the EU Commission regularly. + +The EU Regulation on the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) is the main legislation of the European Union to regulate the production and use of chemicals [b-EU-5]. It restricts the use of many substances in the European Union and is implemented in a similar way in many other countries. + +Regrettable substitution refers to replacing a hazardous substance with another substance that may be less hazardous in the short term. Still, it ultimately has negative consequences for human health or the environment. This can occur when a hazardous substance is phased out or banned and a less hazardous substitute is chosen without considering the potential long-term impacts. For example, a hazardous chemical may be replaced with a less toxic substance but more persistent in the environment and therefore has a longer-lasting effect. Regrettable substitution can also occur when a hazardous substance is replaced with a substance that has unknown or untested long-term effects. To avoid regrettable substitution, as an **SC**, the tenderer must provide evidence that methods or tools have assessed the selected alternative(s) for comparative hazard assessment indicated by the OECD Substitution and Alternatives Assessment Toolbox [b-OECD] or the European Chemicals Agency [b-ECHA]. + +As an **SC**, a tenderer must demonstrate the use of a framework for restricted substance controls (RSC), considering restricted substances under RoHS and REACH along the supply chain for the products to be supplied. Product evaluations, according to the RSC, should, at minimum, cover the areas of product planning/design; supplier conformity; and analytical testing [b-Alfieri]. + +As **TS**: + +- Restriction of chlorinate and brominate substances in plastic parts, except printed circuit boards, electronic components, cables and wiring insulation, and fans; +- Restriction of low-halogen substances in plastic parts; + +- Post-consumer recycled content (PCC): percentage of presence of recycled plastic content in products or packaging. However, verification of the claim based on a mass balance is complex, and may be only an estimation that could vary over time. Given that, it is not required in [b-Alfieri]. + +As **AC**, points must be awarded when no substances on the REACH Candidate List are intentionally added above 0.1% (weight by weight) in each of the following sub-assemblies: + +- Populated motherboard (including CPU, RAM and graphics units); +- Display unit (including backlighting); +- Casings and bezels; +- External keyboard, mouse and trackpad; +- External alternating and direct current power cords (including adapters and power packs). + +As **CPC**, consumables in imaging equipment bring additional technical specifications regarding hazardous substances content in colourants [b-Kaps]. + +### 8.3 Product design + +**Product scoring** [ITU-T L.1023] provides criteria to describe to what extent an ICT product is circular. It proposes a methodology to identify circularity via three circular design guideline groups: first, the ICT product's **durability**; second, the ICT product's ability to be recycled, repaired, reused and upgraded; and third the manufacturers' ability to **recycle, repair, reuse and upgrade** the ICT product put into the market. + +As an **SC**, a tenderer must demonstrate assessment of product scoring and, regarding e-waste minimization, show the degree products were **designed to minimize e-waste** in their: + +- "Ability to recycle, repair, reuse, upgrade – equipment level", particularly considering product-related information about material recycling compatibility, disassembly depth, recycled/renewable plastics, material identification, presence of hazardous substances, presence of critical raw materials and packaging recycling. +- "Ability to recycle, repair, reuse, upgrade – manufacturer level", particularly considering manufacturer provided disassembly information, collection and recycling programmes, environmental footprint assessment knowledge available to improve the equipment material efficiency. + +Relevant indicators for a product constitute **TS** for minimum criteria and **AC** for additional improvements. In L.1023 terms, that translates into high or very high relevance ( $R > 2$ ) indicators, where the margin of improvement must be low or very low ( $MI < 3$ ). + +### 8.4 Needs assessment + +The guideline for achieving the e-waste targets of the Connect 2030 Agenda in [ITU-T L.1031] begins by identifying the need for a resource to achieve a production goal. + +As **CPC**, a preliminary assessment of the **needs** is a preliminary procedure to evaluate the current fleet of equipment and decide to: + +- Retain: for continued use in the same or new function (internal reuse); +- Return: to past supplier, if applicable; +- Reuse: externally as a sale or donation; +- Refurbish, remanufacture, reconfiguration: making a functional product; +- Recycle: sent for end-of-life processing. + +That results in a report about the number and characteristics of the additional new products to procure. + +In that need assessment, the digitalization of ICT services and capacity planning of computing resource needs can result in a reduction of physical device needs into a smaller number of physical machines through hardware virtualization, clustering and consolidating (virtual) devices into a lower number of servers, keeping the minimum number of running instances needed to save energy. Moreover, virtualization can take advantage of physical infrastructure, onsite or remotely, as in cloud-based models of machines or applications as-a-service. + +### 8.5 Interoperability and reusability of components + +As **TS**, examples of desirable accessories available to be procured separately are: adapters for backward compatibility, detachable cables, standardized external power supplies as defined by [ITU-T L.1000], [ITU-T L.1001], [ITU-T L.1002]) and [ITU-T L.1005], chargers and docks. Furthermore, using one standardized interface and ports for charging and data transfer can contribute further to these reductions with USB Type-C cable and connector [b-IEC 62680-1-3] as **AC**. + +As **AC**, equipment with minimal or no accessory components: Decoupling the purchase of accessories from the purchase of new devices, avoiding duplication, results in a possible saving of resources and reduced generation of e-waste. + +### 8.6 Transparency, reporting + +Environmental product declarations (EPD) or LCA can help demonstrate production transparency, as described in [ITU-T L.1031]. + +As **SC**, the ability to provide digitalized product information and documentation, describing product design and manufacturing of each instance, in the form of **product data sheets** or **digital product passports** [b-Navarro], results in the corresponding reduction of paper, reduced manual handling of product information prone to errors, avoidance printed details in packaging, and reduction in packaging. Access to digitalized information allows for more informed, automated and less costly decisions. + +As **CPC**, reporting on reuse and recycling activities helps assess and reduce environmental impacts. + +### 8.7 Procurement process + +**Buy digital**: the use of digital buying tools, such as a procurement platform or portal, that incorporate sustainability requirements for ICT goods and services, requiring suppliers to provide digitalized product-related information and documentation as **SC**. Electronic procurement enables transactions to be made quicker and in a more energy-efficient way as reported in [ITU-T L.1031]. + +**Due diligence** effectively can address the social and environmental risks related to raw material extraction, processing and trading of certain raw materials, and therefore waste prevention, even though it is only related to e-waste. This involves the supply chain and, consequently, an **SC** requirement. + +According to [b-EC-4], there are internationally recognized references to take into account: + +- The ten principles of the United Nations Global Compact [b-UN-2]; +- The Guidelines for Social Life Cycle Assessment of Products [b-UNEP-1]; +- The ILO Tripartite Declaration of Principles concerning Multinational Enterprises and Social Policy [b-ILO]; +- The OECD Due Diligence Guidance for Responsible Business Conduct (RBC) [b-OECD-4]; +- The OECD Due Diligence Guidance for Responsible Supply Chains of Minerals from Conflict-Affected and High-Risk Areas [b-OECD-2]; +- The risks in the battery supply chain in relation to the protection of the natural environment and of biological diversity in line with the Convention on Biological Diversity [b-CBD], + +which also includes the consideration of local communities and the protection and development of those communities. + +Therefore, public procurement must perform due diligence to achieve informed procurement decisions facilitated by collective arrangements in procurement consortia, such as those proposed by CFIT [b-One Planet Network] and supported by digital data, such as digital product passports. + +Furthermore, **CPC** for reporting on e-waste generation and impacts at end-of-life management contributes to assessing compliance with the goal of this clause, connected to traceability. + +### 8.8 Traceability + +Circularity requires the ability to **track and trace** product flows (e.g., devices, parts, materials, e-waste) for their impacts across the forward and reverse supply chain. + +**Tracing** allows for verifying an item's history, location or components using documented recorded identification, finding out about origin, composition and actors involved and deducting from that repair or end-of-life handling possibilities. + +**Tracking** allows to find out what happened to a product in its past and future, which is helpful for impact assessment and reporting. As **CPC**, tracking enables the reporting on the end-destination of ICT equipment. + +Therefore, the **traceability**, as **SC**, and **trackability**, as **CPC**, of products, provenance (suppliers, manufacturers, designers, extended to parts and raw materials) and end-destination is required to be able to identify a product precisely, by product model, batch or even individually (serialized): tracking and tracing are essential for a responsible circular economy, following individual products and flows across the manufacturing and reverse supply chain. Digital linked data and ledgers can facilitate that throughout the life cycle, as considered in digital product passports. + +However, as **AC**, the information provided by suppliers shall be **verifiable** to allow the confirmation of the veracity of assertions about sustainability and circularity. This can be implemented through self/third-party declaration or certification schemes and digitally through digital signatures in data sheets and documents. + +### 8.9 Consumables + +Consumables are replaceable products that are essential to the functioning of the main product. They are typical for imaging equipment products. They can be replaced or replenished by either the end-user or service provider during the normal usage and life span of the imaging equipment product. This is the case for containers and cartridges that hold toner or ink, and that fit onto or into or are emptied into an imaging equipment product. + +Cartridges and consumables in imaging products are responsible for a large part of a product's environmental impacts and, therefore, should be included in the life cycle costing. + +Procurement can include, as **CPC**, a contract for the effective supply of consumables or, as **TS**, a guaranteed supply of consumables during the planned usage period, and that can include, as **CPC**, reporting on supplied consumables, remanufactured cartridges and containers, page-yield declaration, consumable mass resource efficiency (images produced per gram of consumable material). + +At the organization level, contracting leasing agreements, as **CPC**, may promote the use of products with higher durability, extend the real usage time and reduce the amount of waste by encouraging take-back systems and managed printing services. This is because the imaging equipment fleet may be better managed when outsourced [b-Kaps]. + +GPP and the technical specification of printing paper supplies, as **SC**, **TS**, **AC** or **CPC**, including recycled fibre and sustainable sourced paper, is beyond the scope of this Recommendation1. + +### 8.10 Batteries + +Public procurement of ICTs shall take into consideration [ITU-T L.1010] green battery solutions for mobile phones (when applicable) and hand-held information and communication technology solutions and [ITU-T L.1035] sustainable management of batteries and EU relevant guidelines and given the different types of batteries found in ICT equipment per [ITU-T L.1035]. + +The purchase of ICT equipment should consider the battery component view of the impact of batteries on the environment, end-of-life impact as e-waste and its reporting, which necessitates the inclusion, as **CPC**, of specific clauses in procurement tenders. Information on batteries and their evaluation for equipment that is not mobile are in [ITU-T L.1220] and [ITU-T L.1221]. + +## 9 Maximizing useful life + +After prevention, the second strategy to achieve e-waste minimization in the waste hierarchy is optimizing the use phase, including preparation for re-use, mentioned in [ITU-T L.1031] related to "smart usage". It has to do with ensuring that a device, once it has incurred a very high environmental impact from being manufactured, has the longest possible lifespan. This means: + +- Looking carefully at product durability. +- Keeping a product or its parts in the highest value status by ensuring preventive hardware and software maintenance, repair, recondition, refurbishment or remanufacture over its entire usable lifespan. +- Choosing a product considering the environmental usage conditions, such as mobility and expected stresses during usage, such as in mobile and outdoor environments. +- Finding the correct usage of the product in each phase of its lifespan, which translates into finding a purpose/function and user. Changing function may require an upgrade or recondition. Changing user requires reallocation, data wipe and reset to the initial or factory state. +- Using better and longer brings the possibility of buying **refurbished** or **remanufactured** instead of only new. +- Keeping track of products over their lifespan, making those decisions, and knowing about the actions and results. +- Ensuring that after the end-of-use phase in an organization, still usable devices can have a second life as products or ensure their parts are recovered, or the product is recycled correctly. +- Adopting circular business models, not just ownership, such as servitization (device as-a-service), where the service provider can take care of and reallocate devices to maximize useful life. + +### 9.1 Stress during usage + +Mobile devices such as laptops, tablets and smartphones may be subject to drops and other **physical stresses** such as water contact, dust and extreme temperatures that affect durability. However, according to [b-Alfieri], resistance to these stresses improves durability, with higher stress levels expected for **rugged products** used in an outdoor environment. Therefore, it is necessary that + +--- + +1 EU GPP criteria for different product categories: +[https://ec.europa.eu/environment/gpp/eu\\_gpp\\_criteria\\_en.htm](https://ec.europa.eu/environment/gpp/eu_gpp_criteria_en.htm). + +procurers consider evidence from standardized testing methods 2 [b-IEC 60068], [b-ETSI EE EN 019-x] series for environmental conditions and environmental tests for telecommunications equipment, [b-US DoD] (G or H) of the following aspects as part of their procurement process to ensure that they are purchasing durable and reliable products: + +- **Drop testing:** To determine how well a product can withstand accidental drops, impacts or other shock events that may occur during normal use or handling. Robustness of a product affect durability. In a drop test, the product is typically dropped from a predetermined height onto a hard surface, and the resulting damage or functional failure is assessed. Both [b-US DoD] and [b-IEC 60068] provide detailed guidelines and procedures for conducting drop testing, including the specific heights, surfaces and angles that should be used and the criteria for evaluating the results. +- **Ingress protection:** For rugged equipment used for outdoor working activities and other harsh usage environments and conditions, it is desirable to have a rating on ingress protection from solid objects, dust and water, and temperature stress testing. +- **Temperature range:** Resistance to temperature changes and its performance at extreme temperatures to ensure that devices and materials can function reliably in a wide range of temperature conditions. +- **Mechanical stress and shock:** Vibration refers to the rapid oscillation or movement of a device, while shock refers to a sudden impact or force applied to it. Specifically, screen resilience refers to the ability of a device's screen to withstand impact, scratches or other forms of damage. + +These aspects can be **TS** for mobile or rugged products subject to stress or **AC** for stationary and indoor products. + +### 9.2 Management + +Management services, including maintenance, repair, upgrade and disposal, can come from different sources depending on the purchase model or routes: + +- Device only: the public organization should have a dedicated team for these services; +- Device and services, which are outsourced; +- Device as-a-service (DaaS), all is outsourced, under a subscription fee to be tendered in exchange for hardware lease and management services. + +--- + +2 Reported detailed choices in [b-JRC21]: IEC 60068 Part 2-31: Ec (Freefall, procedure 1), MIL-STD-810G, or MIL-STD-810H – Method 516.8 – Shock (Procedure IV) with a drop height of 45 cm. + +![Flowchart illustrating possible procurement routes for public organizations. The process starts with 'Public organization' leading to 'Need assessment'. From 'Need assessment', three routes are possible: 1) 'Purchase devices only (Organization with in-house ICT service)', 2) 'Purchase devices and ICT service (Maintenance, EoL, management, etc.)', and 3) 'Purchase DaaS'. All three routes lead to a common final step: 'Procurement project, including GPP criteria: Operator selection criteria (SC), technical specifications (TS), award criteria (AC), contract performance clauses (CPC)'. A box on the left titled 'Involvement of:' lists 'Procurement experts', 'IT professionals', 'User representatives', and 'Environmental experts', with a bracket pointing to the three initial routes.](c5452f95f3b28f1bfe29e84fbc2e1267_img.jpg) + +``` + +graph TD + PO[Public organization] --> NA[Need assessment] + NA --> P1["Purchase devices only +(Organization with +in-house ICT service)"] + NA --> P2["Purchase devices and ICT service +(Maintenance, EoL, management, etc.)"] + NA --> P3["Purchase DaaS"] + P1 --> PP["Procurement project, including GPP criteria: +Operator selection criteria (SC), technical specifications (TS), +award criteria (AC), contract performance clauses (CPC)"] + P2 --> PP + P3 --> PP + subgraph Involvement + I["Involvement of: +Procurement experts +IT professionals +User representatives +Environmental experts"] + end + Involvement -.-> P1 + Involvement -.-> P2 + Involvement -.-> P3 + +``` + +L.1061(23) + +Flowchart illustrating possible procurement routes for public organizations. The process starts with 'Public organization' leading to 'Need assessment'. From 'Need assessment', three routes are possible: 1) 'Purchase devices only (Organization with in-house ICT service)', 2) 'Purchase devices and ICT service (Maintenance, EoL, management, etc.)', and 3) 'Purchase DaaS'. All three routes lead to a common final step: 'Procurement project, including GPP criteria: Operator selection criteria (SC), technical specifications (TS), award criteria (AC), contract performance clauses (CPC)'. A box on the left titled 'Involvement of:' lists 'Procurement experts', 'IT professionals', 'User representatives', and 'Environmental experts', with a bracket pointing to the three initial routes. + +**Figure 2 – Possible procurement routes identified for public organizations** + +Figure 2 illustrates examples of routes defined in terms of the procurement needs and capabilities of the public organization and the market. + +The aim is to extend the product lifetime, which can provide both environmental and life cycle cost benefits. Although the procurement of refurbished (also called reconditioned) and remanufactured products is currently not common, it is an effective way to contribute to maximizing the useful life of products, which can have the same performance and warranty as new products. + +### 9.3 Maintenance and repair + +For all procurement routes, the duration and conditions of the manufacturer's warranty, as **TS** and the provision of an extended service agreement, as **CPC**, have to be defined in the tender and analysed in the bids. + +In terms of design for repairability options [b-Alfieri], the following are aspects to consider: + +- Hardware design for maintenance: design for maintenance and repairability, as **TS**. +- Hardware maintenance and repair: considering the continued availability period of consumables and spare parts that need a replacement for the maximum usage period planned as part of durability as a **TS**. +- Software maintenance with updates available for the longest period, depending on the product. The ability to update obsolete software, specifically security updates as **TS**, reduces software obsolescence, as firmware and operating system support, particularly security maintenance, is required to keep the device usable, safe for the most prolonged expected usage period. +- Instructions on how to replace the parts must be provided with a service or repair manual as **TS**. The manual must include security measures to ensure safe repair, an exploded diagram of the device illustrating the parts that can be accessed and replaced, which could also be provided in the form of a tutorial video, and the tools required. The service/repair manual must be available online, free of charge. + +**Manufacturer's warranty:** as **TS**, the tenderer must provide written evidence of the manufacturer's warranty, with conditions to invoke the warranty, pick-up and return, incident management, access to diagnostic and repair tools, battery coverage and replacement, and preventive maintenance. + +**Extended services agreement:** as **CPC**, a service-level agreement with conditions to invoke the service, pick-up and return, incident management, access to diagnostic and repair tools, battery coverage and replacement, and preventive maintenance. As part of that, the provider must provide periodical *[monthly/annual]* reporting on its compliance with all the metrics, key performance indicators and other indicators defined by the service-level agreement as **CPC**. + +ICT products are often discarded even before their average first usage life span in cases of malfunction or fault. Even though the fault may be repaired, the product is discarded due to various reasons such as non-availability of spare parts, time for new purchase being less than time for repair or ignorance. One of the solutions to such a problem is to have an OEM AMC regime in which OEM may replace the faulty part with an original one at a reasonable cost and within a reasonable time. This will result in cost savings, extend the useful life of ICT products, reduce the total e-waste generated over a period of time and reduce the exploitation of natural resources. + +The warranty and service agreement criterion is focused on service agreements associated with either procuring equipment or device as-a-service (DaaS) business models. + +The sustainability and SC of the Government of the Netherlands [b-Netherlands] provide many examples of related clauses. + +**Repair:** The repairs should be handled only by certified repair centres during the warranty period to avoid voiding the manufacturer's warranty [b-Alfieri]. + +Outside the warranty period the supplier or a manufacturer authorized repairer should either provide a repair service during the specified contract period or provide critical parts and repair instructions to the purchaser. + +As a basic **TS** criterion, ensure that joining or sealing techniques for the products supplied do not prevent the repair and replacement of the parts (critical components). + +Alternatively, as a comprehensive **TS** criterion, ensure that critical components are easily accessible, repairable and replaceable by using commercially available tools. + +NOTE – This is in line with [b-EN 45554], excluding on-board soldered CPUs. + +Critical parts can vary based on the product category and manufacturer. The manufacturer shall ensure repair or availability of parts that fail most often. + +Longevity and replacement of batteries: part of the design for repairability, as **TS**, ensures that batteries can be easily changed, at least by a maintenance service operator. + +For the cost estimation, as the TCO and the LCC, an estimate of parts to replace (batteries, mechanical parts) must be included. Therefore, the tenderer must provide the details to estimate these as **SC** since these cost estimates can determine the choice. + +### 9.4 Usage + +Extending the life of ICT equipment results in reducing environmental impacts and makes products accessible to a greater number of users, helping reduce pressure on manufacturing new products. + +The management and control of purchased products, as [ITU-T L.1031] proposes, translates into the need to **continuously evaluate and periodically report on the usage performance** of what has been procured with regards to environmental performance and functionality, to assess the efficiency and effectiveness of green procurement processes. + +That performance evaluation can come as a **CPC** on a performance report under an extended services agreement, a **TS** or **AC** over products that can record and provide that information, as usage meters. + +Accessible **usage meters**, built into the product itself or added as an external device, allow usage monitoring and improve information and data about product lifetimes. Usage meters can allow for usage monitoring in several ways. For example, they can track the number of hours the product has + +been used, the number of times it has been turned on or off, or the amount of data that has been processed. + +Knowing the usage history of a product can improve the availability of products by informing maintenance decisions to replace wear-affected components before they are likely to cause failure [b-Botzler]. Furthermore, usage meters can provide reliable information that helps in repair, disposal, sale, donation or recycling decisions. In general, these contribute to minimizing the lack of trust in the quality of second-hand products and the development of second-hand markets. Support for standard remote monitoring functionality from network telemetry or network management protocols of these usage meters or event records helps having this information reflected in an organizational digital inventory system to assist and automate maintenance decisions. + +**Digitalization, digital twinning:** providing supporting information about each product item regarding maintenance, upgrade, repair, reuse, and refurbishment, in a digital and standardized format and associated with a unique product instance identifier (digital twinning, as a digital product passport) enables: + +- Automating product data processing for device management, considering environmental and other criteria. +- Inventory and tracking of assets across the usage phase and beyond, contributing to preventing generating uncontrolled e-waste. +- Facilitating maintenance tasks with more precise information and support for automation. + +Being something new, it can be considered **AC**. + +### 9.5 Secondary usage (reuse) + +Once equipment becomes unsuitable for its primary purpose, it may be upgraded through several strategies, including refurbishment, repair and upgrading. These upgrades may be part of a maintenance and servicing contract that results in a new reuse phase: + +- **Internal reuse** of ICT products refers to the organizational policy and practice of re-using ICT products within the same organization in different functions, rather than disposing of them and replacing them with new ones [ITU-T L.1033]. +- **External reuse:** External reuse is still an option when internal reuse is not possible. This is the practice of donating for social use or selling these products after the initial procurement period. + +There are also **financial considerations**. One of these is **depreciation**, the decrease in the value of an asset over time. By re-using ICT products, organizations can extend the period over which the products depreciate, resulting in a lower overall depreciation cost. Another is **residual value**, the estimated value of an asset at the end of its useful life. + +**Circular procurement models**, such as leasing and service-oriented models, also contribute to the extension of product lifetimes and minimization of environmental impacts by allowing customers to pay for the use of a product rather than purchasing it outright. In leasing or the "as-a-service" contract model, the product is provided, respectively, for a set period or according to a service-level agreement. At the contract end, the product is returned to the provider for refurbishment and re-leased to another customer. This allows the product to be used multiple times rather than discarded after a single use. In addition, this model enables a specialized provider to retain ownership of the product, allowing for better maintenance and maintenance the procurer may perform, further extending its lifespan. + +Reuse comes with the requirement for functionality for **secure data deletion**, as **TS**, for the deletion of user data contained in all data storage devices of the product3. Instructions on using this functionality, the techniques used and the supported secure data deletion standard(s) must be provided in the user manual or by a web link to the manufacturer's webpage. This requirement is established in EU Commission Regulation 2019/424 [b-EC19/424]. + +### 9.6 Energy consumption and energy efficiency in the use phase + +Energy consumption in the use phase has an influence on environmental impact and affects end-of-use decisions based on the TCO. + +The calculated annual Typical Energy Consumption ( $E_{TEC}$ ) in kWh need be reported as the energy efficiency if defined depending on type of product. + +As **TS**, minimum energy performance threshold: the $E_{TEC}$ for each piece of equipment delivered as part of the contract must be less than or equal to a maximum $E_{TEC}$ requirement; similar criteria need be established for the energy efficiency if defined. + +As part of the **AC**, points must be awarded in proportion to the improvement in energy efficiency beyond the minimum. + +Energy consumption and their efficiency need to be tested and based on the applicable standards. A list of applicable standards from ITU, ETSI and ATIS is available in [ITU-T L.1316]. + +Measurement of energy consumption of personal computing products needs to be based on testing and calculations according to [IEC 62623]. + +Alternatively, for some types of products, Energy Star levels from the United States of America or the EPREL labels in the European Union exist. + +### 9.7 Procurement of refurbished and remanufactured products + +The potential to extend a product's life beyond its first use has been addressed by increasing the potential for equipment to be repaired, re-used, and given a second life after its service life with a public authority [b-Alfieri]. + +Another suitable option for facilitating product lifetime extension is the procurement and use of refurbished or remanufactured equipment [b-Alfieri] (criteria area 5). A second use can be ensured through: + +- Refurbishment or reconditioning process of a used product to return to satisfactory working conditions. +- Remanufacturing process of a used product, equivalent to a new product. +- Preparation for reuse: checking, cleaning or repairing. Preparation for reuse can be performed on a product or on a waste item (after recovery), depending on national legislation. + +For that, the tenderer must implement quality assurance and control procedures to ensure the minimum quality of the equipment delivered as part of the contract. The required functionality tests performed on the refurbished or remanufactured equipment must be delivered as a certificate of the tests conducted with the equipment to be reused. The quality of the refurbishment or remanufacture process is therefore a **SC**. + +Quality assurance and control procedures must cover, as a minimum, the following steps: + +- Inspection; +- Reprocessing (e.g., repair, replace or upgrade) if needed; + +--- + +3 According to IEEE 2883 – 22 (2022) "Standard for Sanitizing Storage" [b-IEEE 2883], at least for the level of "Clear". + +- Cleaning; +- Testing; +- Storage; +- Packaging and transport. + +**Quality assurance levels:** The procurer should establish minimum quality requirements as per the examples below: + +- Aesthetic grade: No sign of aesthetic damage should be visible to more than 20 cm. +- Original factory settings: The products must be restored to their original factory settings and must be fully unlocked for use. +- Products must be upgradeable to the latest firmware supported by the OEM (where applicable and technically feasible). +- An instruction manual must be provided. In the absence of physical instruction manuals, a link or reference to the manufacturer's instruction manual should be included when possible. + +Regarding the **bundling procurement of refurbished, remanufactured and new products in the same or different tender:** There are arguments for bundling or separating the procurement of a refurbished or remanufactured product in the same or separate call for tender from new products: + +- Same: a minimum share of refurbished products should be maintained, as a **TS** or **CPC**, in tenders for new products for the following reasons: it is very unusual for a tenderer to issue a specific tender to buy only refurbished products; the demand for refurbished products must be increased to stimulate the offer. +- Separate: [b-Kaps] considers that separate tenders allow small companies that are specialized in refurbished products and do not have new products in their portfolio to participate in the procurement process. + +### 9.8 Batteries + +Following clause 8.10 on batteries, considering [ITU-T L.1010], [ITU-T L.1035], [ITU-T L.1220], [ITU-T L.1221] and the JRC studies and EU regulations [b-Alfieri], the following elements are taken into consideration: prolongation of battery lifetime, and replacement of batteries (see clause 9.3). + +In addition, it is proposed to introduce a minimum technical specification and a more ambitious award criteria linking battery life and cycle endurance, as **TS**. Further battery endurance can be an **AC**. + +In the core criteria of the new proposal of the EU on battery life and endurance, for the verification, the tenderer shall provide test reports showing the batteries' performance in the areas chosen: battery endurance shall be verified according to the test requirements laid down in, for example, [b-IEC 61960-3] or [b-IEC 61960-4]. + +If a comprehensive criterion is used, points shall be awarded for additional battery life and endurance cycles greater than a minimum of 500 cycles (with 80% capacity retention). The cycle performance may be achieved using software which partially charges the battery. In this case, the applicant shall pre-install the software as the default charging routine [b-Alfieri]. + +A pre-installed battery protection software is desirable for product types that can support that, as **TS**, to extend battery endurance (state of health) when the product is systematically in grid operation. The provision of state of health information about the battery is an important **TS**. A battery management system with software to adapt to stop charging before 100% or fully charge when needed, named intelligent charging, as comprehensive criteria **TS** or **AC** for basic criteria. + +## 10 Maximizing recyclability + +This is part of all design, purchase, use and reuse measures that lead to improved recycling and other recovery and minimizing disposal as proposed in [ITU-T L.1031]. Recyclability depends on decisions at the design phase, information to assist in the disassembly and processing, and end-of-life processing. + +**Design for recycling:** with criteria mentioned in [ITU-T L.1023] and in [b-Alfieri]: + +- Marking of plastic casings, enclosures and bezels for the correct indication of the chemistry, with exceptions when unfeasible, as comprehensive **TS**. +- Recyclability of plastic casings, enclosures and bezels – separable inserts and fasteners for computers and displays, where the presence of paints and coatings does not significantly impact the resilience of plastic recycle produced from these components upon recycling, as comprehensive **AC**. +- Declaration of critical raw materials. This is considered in [ITU-T L.1023] 3RUe8, but was found difficult to provide and removed in [b-Alfieri]. Therefore, low MI can be an **AC** to score if provided. + +**Design for dismantling**, mentioned in [ITU-T L.1031] in relation to enabling disassembly, separation and material purification, and in [ITU-T L.1023] in relation to material recycling compatibility. Therefore, low MI can be an **AC** to score if provided. However, this is not included in [b-Alfieri]. + +### Information: + +**Disassembly instructions** are considered in [ITU-T L.1023]. Therefore, a lower MI can be an **AC** to score if provided. + +**Material datasheets, digital product passports, and digitalization:** providing supporting information regarding disassembly, separation and material purification, in a digital and standardized format is a promising future resource. + +**End-of-life management** includes: [b-Alfieri] + +- 1) Secure computer collection, sanitization, reuse and recycling, as **TS**. +- 2) Reporting of the end-destination of ICT equipment as **CPC**. + +The first requires the procurement of end-of-life management services for all ICT devices. Tenderers must provide a service for the re-use and recycling of the whole product or of components requiring selective treatment for equipment that has reached the end of its service life. The service must comprise the following activities: + +- Collection: take-back system, EPR and take-back schemes (in [ITU-T L.1021] and [ITU-T L.1031]) confidential handling and secure data deletion (unless carried out in-house), related to that TS met as mentioned in clause 9.5. +- Functional testing, servicing, repair and upgrading to prepare products for reuse. +- The remarketing of products for reuse. +- Dismantling for component reuse, recycling and/or disposal. + +The following are components requiring selective treatment in accordance with Annex VII of the WEEE Directive [b-EU-3]: + +- mercury-containing components; +- batteries; +- printed circuit boards greater than 10 cm2 in size; +- plastic containing brominated flame retardants; + +- chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) or hydrofluorocarbons (HFCs), hydrocarbons; +- external electric cables; +- polychlorinated biphenyls containing capacitors; +- components containing refractory ceramic fibres; +- electrolyte capacitors containing substances of concern; +- equipment containing gases that are ozone-depleting or have a global warming potential (GWP) above 15; +- ozone-depleting gases must be treated following Regulation (EC) No 1005/2009 [b-EUfbahn]. + +The provider has to demonstrate the capacity and quality to provide end-of-life management services for ICT devices as a **SC**. + +The second, **reporting on the end-destination of ICT equipment (CPC)**: a report on the status of the equipment in the inventory once all items have been processed for re-use, recycling or disposal. The report must identify the proportion of items re-used or recycled, whether they remained within regulatory borders (e.g., in the EU) or were exported, with shipment and treatment information. + +Recycling, despite commonly understood as making used products into new materials, it is about repeating a cycle. By prioritizing the most environmentally sound strategies and responsibly implementing them, it is possible to optimize higher-value recovery and minimize the negative environmental impacts of e-waste. Recycling to maximize preparation for product and component reuse, higher in the e-waste hierarchy, is more environmentally sound than dismantling to recover certain raw materials or energy. Therefore, any verifiable effort to support preparation for reuse must be encouraged. However, methodological developments are needed to be able to measure that in a standardized and manageable way. + +## 11 Summary of requirements + +The following table provides a brief summary of the requirements, see details in previous clauses, to achieve the main aims or circularity goals through sustainable procurement: + +- Minimize any resulting amount of e-waste produced, and the adverse effects (W, clause 8). +- Maximize the use of energy-efficient equipment (W and L). +- Maximize usable life or lifespan (L, clause 9). +- Increase the recyclability, thereby contributing to the circular economy (R, clause 10). + +They are organized by order of preference according to the e-waste hierarchy in [ITU-T L.1031] and into the context of [b-ITU-T L.Suppl 20]. + +As described in the overview of clause 6, procurement criteria are grouped into four main types: SC, technical specifications award criteria, and contract performance clause (CPC). + +The table shows relevance by product groups, with their specific issues: + +- Stationary computers, terminals, network devices (STA): cooling, energy efficiency in the office, server and data centre environments. +- Monitors (MON): energy efficiency, substances. +- Mobile/battery-powered computers, terminals, smartphones (MOB): batteries, mobility, outdoors. +- Imaging equipment (IMA): printing supplies and consumables such as ink and toner. + +The relevance of criteria per product group is marked in the table according to ambition level by an "X" (core) or a "C" (comprehensive) criteria, while a blank " " means not relevant or not applicable. + +| Criteria | Product group | | | | Cat | +|------------------------------------------------------------------------------------------------------------------------------------------|---------------|-----|-----|-----|-----| +| | STA | MON | MOB | IMA | | +| 8 Minimization of the generation of e-waste and its adverse effects | | | | | | +| Collecting environmental impact indicators from procured goods and services | X | X | X | X | SC | +| Demonstrating use of a framework for RSC (e.g., compliance with RoHS directive) | X | X | X | X | | +| Demonstrating assessment of product scoring | X | X | X | X | | +| Degree to which products were designed to minimize e-waste | X | X | X | X | | +| Declaration of critical raw materials in product design | X | X | X | X | | +| Provide digitalized product information and documentation, describing product design and manufacturing | X | X | X | X | | +| Provide information about the supply chain required for due diligence | X | X | X | X | | +| Traceability of products and provenance | X | X | X | X | | +| Restriction of chlorinate and brominate substances in plastic parts | X | X | X | X | TS | +| Restriction of low-halogen substances in plastic parts | X | X | | | | +| Percentage of presence of recycled plastic content in products or packaging | X | X | X | X | | +| Accessories available to be procured separately | X | X | X | X | | +| Standardized interfaces and ports | X | X | X | X | | +| Information provided by suppliers should be verifiable | X | X | X | X | AC | +| Avoidance of regrettable substitution | X | X | X | X | | +| Equipment without accessories | | | X | | | +| Separate charger | | | X | | | +| Collecting environmental impact indicators from procured goods and services | X | X | X | X | CPC | +| Hazardous substances content in colourants | | | | X | | +| Preliminary procedure to need assessment of the current fleet of equipment | X | X | X | X | | +| Reporting on reuse and recycling activities | X | X | X | X | | +| Reporting on e-waste generation and impacts at end-of-life management | X | X | X | X | | +| Tracking and reporting on the end-destination of ICT equipment | X | X | X | X | | +| Contract for the effective supply of consumables | | | | X | | +| Guaranteed supply of consumables during the planned usage | | | | X | | +| Reporting on supplied consumables, remanufactured cartridges and containers, page-yield declaration, consumable mass resource efficiency | X | X | X | X | | +| Contracting of leasing agreements | X | X | X | X | | +| Reporting on environmental impact of batteries, end-of-life impact as e-waste | X | X | X | X | | + +| 9 Maximizing useful life and energy efficiency | STA | MON | MOB | IMA | | +|----------------------------------------------------------------------------------------------------------------------------------------------|------------|------------|------------|------------|----| +| Procuring durable and reliable products | X | X | X | X | SC | +| Procuring refurbished and remanufactured products to extend product lifetime | X | X | X | X | | +| Quality assurance/control procedures for refurbished/remanufactured products | X | X | X | X | | +| Provide the details to estimate TCO and LCC | X | X | X | X | | +| Durability testing under stress | | | X | | TS | +| Drop testing and other standardized testing methods, for rugged products | | | C | | | +| Ingress protection rating, for rugged equipment | | | C | | | +| Resistance to temperature changes and performance at extreme temperatures, for rugged products | | | X | | | +| Vibration and shock resistance, for rugged products | | | C | | | +| Duration and conditions of manufacturer's warranty | X | X | | X | | +| Design for maintenance and repairability | X | X | | X | | +| Continued availability of consumables | | | | X | | +| Continued availability of spare parts | | | X | | | +| Software maintenance with updates available for the longest period | X | X | | X | | +| Availability of service or repair manual | X | X | | X | | +| Written evidence of the manufacturer's warranty | X | X | | X | | +| Ensure that joining or sealing techniques for the products supplied do not prevent the repair and replacement of the critical parts (basic) | X | X | | X | | +| Ensure that critical components are easily accessible, repairable and replaceable by the use of commercially available tools (comprehensive) | C | C | | C | | +| Ensure that batteries can be easily changed, at least by a maintenance service operator | | | X | | | +| Functionality of secure data deletion | X | | | X | | +| Minimum energy performance | X | X | | X | | +| Minimum share of refurbished products in tenders for new products | | | X | | | +| Information on battery state of health | | | X | | | +| Battery life and cycle endurance | | | X | | | +| Pre-installed battery protection software | | | X | | | +| Stress resistance, for stationary and indoor products | X | X | X | X | AC | +| Drop testing and other standardized testing methods, for stationary and indoor products | X | X | X | X | | +| Ingress protection rating, for stationary and indoor products | X | X | X | X | | +| Resistance to temperature changes and performance at extreme temperatures, for stationary and indoor products | X | X | X | X | | +| Vibration and shock resistance, for stationary and indoor products | X | X | X | X | | +| Further battery endurance | X | X | X | X | | +| Availability of usage meters built into the product | X | X | X | X | | +| Providing information about each product item, in a digital and standardized form for automating management, inventory and maintenance | X | X | X | X | | + +| | | | | | | +|---------------------------------------------------------------------------------------------------------------|------------|------------|------------|------------|-----| +| Improvement in energy efficiency beyond the minimum | X | X | X | X | | +| Battery management system for intelligent charging (AC/TS) | X | X | X | X | | +| Provision of extended service agreement for maintenance and repair | X | X | X | X | CPC | +| Duration and conditions of extended service agreement with service-level | X | X | X | X | | +| Periodic reporting on service-level compliance of extended services | X | X | X | X | | +| Performance report under an extended services agreement | X | X | X | X | | +| Minimum share of refurbished products in tenders for new products | X | X | X | X | | +| Devices as-a-service | X | X | X | X | | +| 10 Maximizing recyclability | STA | MON | MOB | IMA | | +| Demonstrate capacity to provide end-of-life management services | X | X | X | X | SC | +| Secure computer collection, sanitization, re-use and recycling | X | X | X | X | TS | +| Confidential handling and secure data deletion | X | X | X | X | | +| Dismantling for component re-use, recycling and/or disposal | X | X | X | X | | +| Marking of plastic casings, enclosures and bezels for the correct indication of the chemistry (comprehensive) | C | C | | | | +| Recyclability of plastic casings, enclosures and bezels (comprehensive) | C | | | | AC | +| Design for dismantling, material recycling compatibility (comprehensive) | C | | | | | +| Availability of disassembly instructions | X | X | X | X | | +| Declaration of critical raw materials | X | X | X | X | CPC | +| Reporting on end-destination of ICT equipment | X | X | X | X | | + +## Bibliography + +- [b-ITU-T L.Suppl. 20] ITU-T L Suppl. 20 (2015), Green public ICT procurement. + +- [b-ITU-1] ITU (2012), *Toolkit on environmental sustainability for the ICT sector*. +[https://www.itu.int/dms\\_pub/itu-t/oth/4B/01/T4B010000060001PDFE.pdf](https://www.itu.int/dms_pub/itu-t/oth/4B/01/T4B010000060001PDFE.pdf) +- [b-ITU-2] ITU Newslog (2012), *Guidance on green ICT procurement*. +[http://www.itu.int/dms\\_pub/itu-t/oth/4B/01/T4B010000040001PDFE.pdf](http://www.itu.int/dms_pub/itu-t/oth/4B/01/T4B010000040001PDFE.pdf) +- [b-ITU-3] ITU, GovStack, Circular Electronics Partnership (2023), *The Circular and Sustainable Public Procurement Guide for ICT*. +- [b-EN 4553] EN 45553:2020, *General method for the assessment of the ability to remanufacture energy-related products*. +- [b-EN 45554] CENELEC EN 45554:2020, *General methods for the assessment of the ability to repair, reuse and upgrade energy-related products*. +- [b-ETSI EE EN 019-x] 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(2021), *Revision of the EU Green Public Procurement (GPP) Criteria for Computers and Monitors (and extension to Smartphones)*. doi:10.2760/124337. +- [b-Botzler] M. Botzler, P. Zeiler and B. Bertsche (2014), *Failure prediction by means of advanced usage data analysis*, 2014 Reliability and Maintainability Symposium, pp. 1–6. doi: 10.1109/RAMS.2014.6798508. +- [b-CBD06] Convention on biological diversity (2006), *Decision COP VIII/28 Voluntary guidelines on Biodiversity-Inclusive impact assessment*. + +- [b-DEFRA] United Kingdom Department for Environment Food and Rural Affairs (2006), *Procuring the Future*. +[https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment\\_data/file/69417/pb11710-procuring-the-future-060607.pdf](https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/69417/pb11710-procuring-the-future-060607.pdf) +- [b-Dorp] K. van Dorp, (2002) *Tracking and tracing: a structure for development and contemporary practices*, Logistics Information Management, Vol. 15, No. 1, pp. 24–33. +- [b-EC-1] Commission Regulation (EU) 2019/424 of 15 March 2019 laying down ecodesign requirements for servers and data storage products pursuant to Directive 2009/125/EC of the European Parliament and of the Council and amending Commission Regulation (EU) No 617/2013. +- [b-EC-2] European Commission (2023) *GPP Training Toolkit*. +[https://ec.europa.eu/environment/gpp/toolkit\\_en.htm](https://ec.europa.eu/environment/gpp/toolkit_en.htm) +- [b-EC-3] European Commission (2020), *Proposal for a Regulation of the European Parliament and of the Council concerning batteries and waste batteries, repealing Directive 2006/66/EC and amending Regulation (EU) No 2019/1020*, COM/2020/798 + +- [b-EC-4] European Commission (2020) *EU Green Public Procurement Criteria for Imaging Equipment, Consumables and Print services*, SWD (2020) 148. +[https://ec.europa.eu/environment/gpp/pdf/20032020\\_EU\\_GPP\\_criteria\\_for\\_imaging\\_equipment\\_2020.pdf](https://ec.europa.eu/environment/gpp/pdf/20032020_EU_GPP_criteria_for_imaging_equipment_2020.pdf) +- [b-ECHA] European Chemicals Agency, *How to substitute?* + +- [b-EU-1] European Union, Communication (2008) (COM (2008) 400), *Public procurement for a better environment*. +- [b-EU-2] European Union Commission (2011), *Green public procurement – Office IT equipment – Technical background report*. +- [b-EU-3] European Directive 2012/19/EU of the European Parliament and of the Council of 4 July 2012 on waste electrical and electronic equipment (WEEE). +- [b-EU-4] Regulation (EC) No 1005/2009 of the European Parliament and of the Council of 16 September 2009 on substances that deplete the ozone layer. + +- [b-EU-5] European Union (2017) *Registration, Evaluation, Authorisation and Restriction of Chemicals*. +- [b-EU-6] European Union (2011), *Document CL2011L0065EN0170010.0001.3bi\_cp 1..4 (europa.eu), amending Directive 2011/65/EU on the restriction of the use of certain hazardous substances in electrical and electronic equipment*. +- [b-ICLEI] ICLEI – Local Governments for Sustainability Europet (2017) *Life Cycle Costing: State of the art report*. 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[https://web.archive.org/web/20060319071709/http://www.gartner.com/DisplayDocument?doc\\_cd=131837](https://web.archive.org/web/20060319071709/http://www.gartner.com/DisplayDocument?doc_cd=131837) +- [b-Navarro] Navarro, Leandro, et al. (2022) *Digital transformation of the circular economy: digital product passports for transparency, verifiability, accountability*. [https://people.ac.upc.edu/leandro/docs/DPP\\_DLT\\_ACMJ22.pdf](https://people.ac.upc.edu/leandro/docs/DPP_DLT_ACMJ22.pdf) +- [b-Netherlands] Government of the Netherlands, . *SPP criteria tool*. +- [b-OECD-1] Organisation for Economic Co-operation and Development, *Substitution and Alternatives Assessment Toolbox: Alternatives assessment and substitution of harmful chemicals*, +- [b-OECD-2] Organisation for Economic Co-operation and Development (2016), *OECD Due Diligence Guidance for Responsible Supply Chains of Minerals from Conflict-Affected and High-Risk Areas, Third Edition*, Paris, OECD Publishing. +- [b-OECD-3] Organisation for Economic Co-operation and Development (2017), *Public Procurement for Innovation: Good Practices and Strategies*, OECD Public Governance Reviews, Paris, OECD Publishing. +- [b-OECD-4] Organisation for Economic Co-operation and Development (2018), *OECD Due Diligence Guidance for Responsible Business Conduct*, Paris, OECD Publishing. +- [b-One Planet Network] **One Planet Network** (2021) *Circular & Fair ICT Pact*. +- [b-UN-1] United Nations (2005), *2005 World Summit Outcome, Resolution A/60/1, adopted by the General Assembly on 15 September 2005*. [https://www.un.org/en/development/desa/population/migration/generalassembly/docs/globalcompact/A\\_RES\\_60\\_1.pdf](https://www.un.org/en/development/desa/population/migration/generalassembly/docs/globalcompact/A_RES_60_1.pdf) +- [b-UN-2] United Nations Global Compact (2017), *United Nations Global Compact Progress Report: Business Solutions to Sustainable Development*. + +- [b-UNDP] United Nations Development Programme, *What are the Sustainable Development Goals?* +- [b-UNEP-1] United Nations Environment Programme (2009), *UNEP Guidelines for social life cycle assessment of products.* +- [b-UNEP-2] United Nations Environment Programme (2017), *Guidance to assist Parties in developing efficient strategies for achieving the prevention and minimization of the generation of hazardous and other wastes and their disposal.* Final revised version UNEP/CHW.13/INF/11/Rev.1. +- [b-UNEP-3] United Nations Environment Programme (2018), *Building Circularity into our Economies through Sustainable Procurement.* +- [b-UNOPS] United Nations Office for Project Services (2009), *A Guide to Environmental Labels for Procurement Practitioners of the United Nations System.* [https://www.ungm.org/Areas/Public/Downloads/Env\\_Labels\\_Guide.pdf](https://www.ungm.org/Areas/Public/Downloads/Env_Labels_Guide.pdf) +- [b-US DoD] United States Department of Defense MIL-STD-810G (2019), *Department of Defense Test Method Standard: Environmental engineering considerations and laboratory tests.* + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1070-202311-I_PDF-E/0538daaa5583c23e17db3a12f2281a55_img.jpg b/marked/L/T-REC-L.1070-202311-I_PDF-E/0538daaa5583c23e17db3a12f2281a55_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..d4d8969f805414689ab79cfd08c333d454d482b3 --- /dev/null +++ b/marked/L/T-REC-L.1070-202311-I_PDF-E/0538daaa5583c23e17db3a12f2281a55_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:636c3839edff955a5b6208530b05fa1c983ab153d90f00216517a7a99478b988 +size 7074 diff --git a/marked/L/T-REC-L.1070-202311-I_PDF-E/raw.md b/marked/L/T-REC-L.1070-202311-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..1e21d1d1404af3f6b36b1d612556a15ed4248ce7 --- /dev/null +++ b/marked/L/T-REC-L.1070-202311-I_PDF-E/raw.md @@ -0,0 +1,913 @@ + + +# Recommendation**ITU-T L.1070 (11/2023)** + +SERIES L: Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant + +E-waste and circular economy + +--- + +### **Global digital sustainable product passport opportunities to achieve a circular economy** + +![ITU logo](0538daaa5583c23e17db3a12f2281a55_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with white lines representing latitude and longitude, and the letters 'ITU' in a bold, blue, sans-serif font superimposed on the globe. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +## **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|--------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| Infrastructure including node elements (except cables) | L.200-L.249 | +| General aspects and network design | L.250-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| Optical fibre cable maintenance | L.300-L.329 | +| Infrastructure maintenance | L.330-L.349 | +| Operation support and infrastructure management | L.350-L.379 | +| Disaster management | L.380-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1070 + +## Global digital sustainable product passport opportunities to achieve a circular economy + +## Summary + +Recommendation ITU-T L.1070 provides an overview of global and common opportunities to represent sustainability, mainly environmental related (including human health), details about digital technology products, either collective information and communication technology (ICT) product models, batches or individual product items. These product details are intended for representation in digital format instead of on paper. The details can represent design-related information, products at the time of manufacturing, including relevant information for product transparency and a potential for a circular lifecycle, such as details related to the origin of materials composition, design, manufacturing, energy consumption, maintenance, repair, preparation for reuse, final recycling and may include links to related documentation. Product details can include or relate to information that changes over the lifespan of a product as a result of reconfiguration events, including repair, upgrade, usage, sale and final recycling. The details should exclude any personal or business-sensitive information. + +Recommendation ITU-T L.1070 provides an overview of sustainability opportunities, environmental related, about product-related digital information common to all ICT products, with global scope for harmonization, i.e., relevant to any region, that can support the development of the circular economy of ICT products. Product-related digital information can be represented under digital technology, such as product identifiers, data formats, linked data and system architectures. It relates to and can complement regional and global standards. + +## History\* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.1070 | 2023-11-06 | 5 | 11.1002/1000/15598 | + +## Keywords + +Digital, digital product passport, environmental sustainability, ICT, product details. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2023 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-----------------------------------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 3 | +| 4 Abbreviations and acronyms ..... | 4 | +| 5 Conventions ..... | 5 | +| 6 Description and scope of the digital product passport..... | 5 | +| 7 Circular digital products ..... | 6 | +| 7.1 Objectives for a circular economy..... | 7 | +| 7.2 Lifecycle stages ..... | 7 | +| 7.3 Challenges in the electronics lifecycles..... | 8 | +| 7.4 Digitalizing information about ICT product lifecycles ..... | 8 | +| 7.5 Desirable properties of product information ..... | 11 | +| 7.6 Definition of the product ..... | 14 | +| 8 Guidance for implementation ..... | 15 | +| 8.1 DPP architecture considerations..... | 17 | +| Appendix I – Related work, standards and data sources concerning environmental sustainability ..... | 18 | +| I.1 Related work..... | 18 | +| I.2 Standards and data sources related to sustainability..... | 18 | +| Appendix II – A simple estimate of the volume of data and transactions ..... | 22 | +| Bibliography..... | 23 | + +# Introduction + +The 2005 World Summit on Social Development [b-UN 2005] identified sustainable development goals (SDGs) with three pillars: economic development; social development; and environmental protection. The economic pillar has to do with trade. The social pillar has to do with people: workers; users; and other people and collectives affected. The environmental pillar has to do with the challenges of consuming materials to produce products and energy to power them, their use, the production of electrical and electronic waste (e-waste), and any indicators related to positive and negative effects on people and nature. + +In the context of sustainability, Agenda 2030 [b-UN 2015] establishes a shared blueprint for peace and prosperity for people and the planet, now and into the future. It specifies SDGs for social, economic, and ecologically sustainable development [b-UN 2021]. + +There are well-defined targets for the climate crisis. The Intergovernmental Panel on Climate Change (IPCC) specifies the different trajectories, specifically compliance with the 1.5°C objectives described by the IPCC Special Report on 1.5°C [b-IPCC 2018]. To meet this goal, the world should cut emissions to net zero by 2050. + +ITU defined the Connect 2030 Agenda with Goal 3 on Sustainability, where ITU recognizes the need to manage emerging risks, challenges and opportunities from the rapid growth of information and communication technology (ICT). There are several initiatives to speed up reductions in environmental impact like SDG 2030 (United Nations Environment Programme (UNEP)), Race to Zero (26th UN Climate Change Conference of the Parties (COP26)), NetZero, and science-based targets. Data is needed to implement these initiatives. + +The Aarhus convention [b-UNECE Aarhus] and the related Escazu agreement [b-UNECLAC Escazu] recognize environmental rights related to access to environmental information and the need for mechanisms to render these rights effective. + +ICT products (electrical and electronic equipment such as routers, switches; consumer products like smartphones) have environmental, social and economic impacts at each stage in their lifecycle, starting from the supply chain, including the reverse supply chain, ending as e-waste at end-of-life. It has to do with energy, natural resource consumption and emissions of various kinds, to name a few. + +Currently, more than 6 billion new ICT products are sold annually worldwide. There are estimates of 1.5 billion smartphones [b-Statista] in 2021, 126 million desktop computers, 659 million laptops, and 513 million wireless fidelity routers produced every year (2021). These numbers are expected to grow over the next 5–10 years with new "smart" technologies [b-ITU-T L.1024]. + +As a result of growing production and sales, e-waste is one of the fastest growing waste stream, most of it discarded in the municipal waste stream, leading to a loss of secondary resources [b-UNU] valued at US\$57 billion in 2019 (more than the gross domestic product of many countries) Additionally, e-waste is often shipped illegally to developing countries [b-UN 2010]. + +The contribution of ICT in terms of electricity use is a significant factor: by 2030, ICTs may use a larger share of global electricity and globally released greenhouse gas (GHG) emissions [b-Andrae 2020a]. Clean sources of energy and locality can nevertheless help reduce GHG emissions [b-Amponsah]. + +However, for some ICT products, upstream activities of raw material acquisition, transport and production contribute most to the environmental impact [b-Andrae 2016]. + +In contrast, ICTs can enable vast efficiencies in social and economic life through digital solutions that can improve energy efficiency, inventory management, and reduction of travel and transportation impacts (e.g., telework and videoconferencing, substituting physical products with digital information). This capacity is referred to as second-order or enablement effects. + +[b-ITU-T L.1470] defines GHG emissions trajectories for the ICT sector as compatible with the United Nations Framework Convention on Climate Change (UNFCCC) Paris Agreement. Therefore, the digital world is part of the problem and may be part of the solution. + +The circular economy (CE), and the term circularity, is about "designing out waste and pollution, keeping products and materials in use, and regenerating natural systems" [b-EMF-B]. In the context of ICT products, circularity aims to achieve the best use of ICT products with maximal lifespan, which helps decarbonize the environment. A circular approach in the electronics industry is widely accepted as the required transformation to move away from a linear "take-make-waste" model of production and consumption [b-EMF-A]. + +With a focus on environmental sustainability and circularity in the DPP for ICT products, this Recommendation presents: + +- the description of the scope of the digital product passport (DPP) in clause 6; +- the description of DPP opportunities; +- the definition of the required ICT product types to consider in DPPs; +- the definition of required principles and properties of digital product information in DPPs, all in clause 7; +- the feasibility of implementing these opportunities in a global DPP system is discussed in clause 8. + +This Recommendation provides a basis for other DPP standards about detailed information models for ICT products, specific ICT product categories, as well as regional and global DPP standards. + +This Recommendation was developed jointly by the European Telecommunications Standards Institute Technical Committee Environmental Engineering (ETSI TC EE) and ITU-T Study Group 5. It is published as Recommendation ITU-T L.1070 and [b-ETSI TS 103 881], which are technically equivalent, by ITU and ETSI, respectively. + + + +# Recommendation ITU-T L.1070 + +## Global digital sustainable product passport opportunities to achieve a circular economy + +# 1 Scope + +This Recommendation specifies a digital product passport (DPP) for information and communication technology (ICT) products to be represented in digital format, including an overview of the opportunities and benefits to include information relevant to sustainability, mainly environmental related, focusing on circularity and transparency. + +This Recommendation does not define which items should be filled out for all or different product families in their DPP nor the targets, limits or specific requirements a product has to meet. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T L.1023] Recommendation ITU-T L.1023 (2023), *Assessment method for circularity performance scoring*. +- [ITU-T L.1034] Recommendation ITU-T L.1034 (2022), *Adequate assessment and sensitization on counterfeit information and communication technology products and their environmental impact*. +- [ITU-T L.1102] Recommendation ITU-T L.1102 (2016), *Use of printed labels for communicating information on rare metals in information and communication technology goods*. +- [ITU-T L.1410] Recommendation ITU-T L.1410 (2014), *Methodology for environmental life cycle assessments of information and communication technology goods, networks and services*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +- 3.1.1 authenticity** [b-ISO/IEC 27000]: Property that an entity is what it claims to be. +- 3.1.2 batch** [b-EC 2023]: A subset of a specific model composed of all products produced in a specific manufacturing plant at a specific moment in time. +- 3.1.3 circular economy** [b-ITU-T L.1604]: An economy closing the loop between different life cycles through design and corporate actions/practices that enable recycling and reuse in order to use raw materials, goods and waste in a more efficient way. + +NOTE 1 – The circular economy concept distinguishes between technical and biological cycles, the circular economy is a continuous, positive development cycle. It preserves and enhances natural capital, optimizes + +resource yields, and minimizes system risks by managing finite stocks and renewable flows, while reducing waste streams. + +NOTE 2 – Definition adapted from [b-ITU-T L.1022] and [b-ITU-T L.1020]. + +**3.1.4 circularity:** Designing out waste and pollution, keeping products and materials in use, and regenerating natural systems. + +NOTE – The definition is based on [b-EMF-B]. + +**3.1.5 component** [b-ETSI EN 303 808]: Hardware constituent of a product that cannot be taken apart without destruction or impairment of its intended use. + +NOTE – A populated printed circuit board may be considered a component and/or a part from the perspective of this Recommendation. + +**3.1.6 digitalization** [b-OECD]: Use of digital technologies and data as well as interconnection that results in new or changes to existing activities. + +**3.1.7 e-waste; WEEE** [b-ITU-T L.1031]: Electrical or electronic equipment that is waste, including all components, sub-assemblies and consumables that are part of the equipment at the time the equipment becomes waste. + +NOTE – The terms e-waste and waste electrical and electronic equipment (WEEE) are used interchangeably. + +**3.1.8 extended producer responsibility (EPR)** [b-ITU-T L.1021]: A policy principle to promote total life cycle environmental improvements of product systems by extending the responsibility of the manufacturers of the product to various parts of the entire life cycle of the product, and especially to the take-back, recycling and final disposal of the product. + +**3.1.9 ICT goods** [ITU-T L.1410] or [b-ETSI ES 203 199]: Tangible goods deriving from or making use of technologies devoted to or concerned with: the acquisition, storage, manipulation (including transformation), management, movement, control, display, switching, interchange, transmission or reception of a diversity of data; the development and use of the hardware, software, and procedures associated with this delivery; and the representation, transfer, interpretation, and processing of data among persons, places, and machines, noting that the meaning assigned to the data is preserved during these operations. + +NOTE – [b-ETSI ES 103 199] uses the word "equipment" instead of "goods". + +**3.1.10 ID tag** [b-ITU-T Y.2213]: A physical object which stores one or more identifiers and optionally application data such as name, title, price, address, etc. + +**3.1.11 integrity** [b-Wikipedia]: The maintenance of, and the assurance of, data accuracy and consistency. + +**3.1.12 intermediate product** [b-EC 2022]: A product that requires further manufacturing or transformation such as mixing, coating or assembling to make it suitable for end-users. + +**3.1.13 item** [b-EC 2023]: A single unit of a model. + +**3.1.14 model** [b-EC 2023]: A version of a product of which all units share the same technical characteristics and the same model identifier. + +**3.1.15 product** [b-EC 2022]: Any physical good that is placed on the market or put into service. + +NOTE – ICT goods are ICT products. + +**3.1.16 refurbishment** [ITU-T L.1023]: Industrial process which produces a product from used products without any changes influencing safety, original performance, purpose or type of the product. + +NOTE – New and/or used parts can be used during refurbishment. The definition is based on [b-ETSI EN 303 808]. + +**3.1.17 remanufacturing** [ITU-T L.1023]: Industrial process which produces a product from used products or used parts where at least one change is made which influences the safety, original performance, purpose or type of the product. + +NOTE – The product created by the remanufacturing process may be considered a new product when placing on the market. The definition is based on [b-ETSI EN 303 808]. + +**3.1.18 repair** [b-ITU-T L.1022]: Process of returning a faulty product to a condition where it can fulfil its intended use. + +**3.1.19 risk** [b-EC 2020]: The combination of the probability of occurrence of harm and the severity of that harm limited to human health or safety of persons, to property or to the environment. + +**3.1.20 servitization** [b-ITU-T L.1024]: The process of creating value by adding services to products. In more detail 'the offering in terms of "goods or services" through "goods and services" to the marketing of bundles of "goods + services + support + knowledge + self-service".' + +NOTE – See [b-Kowalkowski] for a definition as "The transformational processes whereby a company shifts from a product-centric to a service-centric business model and logic". + +**3.2.21 supply chain due diligence** [b-ITU-T L.1061]: The obligations of the economic operator which places a product on the market, in relation to its management system, risk management, third party verifications by notified bodies and disclosure of information with a view to identifying and addressing actual and potential risks linked to the sourcing, processing and trading of the raw materials required for product manufacturing. + +**3.1.22 sustainable development** [b-UN 1987]: Development that meets the needs of the present without compromising the ability of future generations to meet their needs. + +**3.1.23 tag-based identification** [b-ITU-T Y.2213]: The process of specifically identifying a physical or logical object from other physical or logical objects by using identifiers stored on an ID tag. + +**3.1.24 traceability** [b-ISO 9000]: Ability to trace the history, application or location of an object. + +**3.1.25 tracing** [b-van Dorp]: The ability to follow the supply chain upward and determine the source of a product. + +**3.1.26 tracking** [b-van Dorp]: The ability of keeping track of the flows of products transporting from upstream to downstream in a supply chain. + +## **3.2 Terms defined in this Recommendation** + +This Recommendation defines the following terms: + +**3.2.1 authenticity**: Ability of proving an assertion, such as the identity of a computer system user. + +**3.2.2 accountability**: Equivalent to answerability, liability and the expectation of account reporting, with the obligation to inform about (past or future) actions and decisions, to justify them. + +NOTE – Adapted from [b-Dykstra] [b-Schedler]. + +**3.2.3 centralization**: Data, function, process, system where a single entity or a small group, has exclusive control or responsibility for it. + +**3.2.4 collective product**: A product batch or product model with common characteristics for multiple product items. + +**3.2.5 decentralization**: Property of data, function, process or system that is not centralized or controlled by a single or few entities. + +**3.2.6 digital product passport**: A structured collection of product-specific data conveyed through a unique identifier. + +NOTE – Definition based on European Commission document [b-EC 2022]. + +**3.2.7 digital product passport provision:** Process and responsibility of collecting, creating, maintaining, validating, supplementing, storing and delivering data from source(s) to targets, which includes the provision of a service and managing the data related to it. + +**3.2.8 digital product passport supplier:** Any product operator responsible for provisioning (supplying) the associated data that is included in or linked to a digital product passport. + +NOTE – Product operator can be a manufacturer, refurbishment service provider or importer who introduces the product to market, whereas an external third party digital product passport (DPP) service provider is not considered as a DPP supplier as they are not primarily responsible for the product details contained in the DPP. + +**3.2.9 economic operator:** Include the manufacturer, authorized representative, importer, distributor, fulfilment service provider, or any legal person with legal responsibility concerning manufacture. + +NOTE – Adapted from [b-EC 2020]. + +**3.2.10 global digital sustainable product passport:** The subset of a digital product passport, global in regional scope, focused on environmental sustainability aspects. + +**3.2.11 identity:** A unique indication of a person or thing, verified by authentication. + +**3.2.12 individual product:** A product item. + +**3.2.13 information accessibility:** Ability to access and benefit from information to the widest range of actors and situations. + +**3.2.14 information composability:** Ability to combine and assemble self-contained and stateless information components, as with structured linked data. + +**3.2.15 information confidentiality:** A set of rules or a promise to limit access or place restrictions on certain types of information. + +**3.2.16 information privacy:** The relationship between the collection and dissemination of data. + +**3.2.17 information transparency:** Clarity about relevant details, needed for a decision or an assessment. + +**3.2.18 information verifiability:** The ability to review, inspect, audit, test to establish, document and confirm the veracity of an assertion. + +**3.2.19 linear economy:** Cradle-to-grave; the 'take-make-waste' model; i.e., extracting, manufacturing, using and wasting. + +NOTE – Paraphrased from [b-ITU-T L.1022]. + +**3.2.20 modular product:** A product that, in a container, includes module(s) (component product(s)) that can easily be replaced or added. + +**3.2.21 product operator:** Any actor that can transform and supply modified products and therefore can supply the information a digital product passport conveys about them, as a result of manufacture or other operations. + +NOTE – These other operations could be: packaging, configuration, maintenance, repair, upgrade, refurbishment, remanufacturing or recycling. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-----|---------------------------------------------------| +| ADR | International Carriage of Dangerous Goods by Road | +| CE | Circular Economy | +| CRT | Cathode Ray Tube | + +| | | +|---------|------------------------------------------------------------------------------| +| DGR | Dangerous Goods Regulations | +| DPP | Digital Product Passport | +| EPR | Extended Producer Responsibility | +| EPREL | European Product Registry for Energy Labelling | +| e-waste | electrical and electronic waste | +| FAIR | Findable, Accessible, Interoperable and Reusable | +| GHG | Greenhouse Gas | +| GHS | Globally Harmonized System | +| HMIS | Hazardous Materials Identification System | +| HS | Harmonized System | +| ICT | Information and Communication Technology | +| ID | Identifier | +| LCA | Lifecycle Assessment | +| PCDS | Product Circularity Data Sheet | +| PIC | Prior Informed Consent | +| RID | Regulations Concerning the International Carriage of Dangerous Goods by Rail | +| SCIP | Substances of Concern In articles as such or in complex objects (Products) | +| SDG | Sustainable Development Goal | +| SDS | Safety Data Sheet | +| TPS | Transactions Per Second | +| URL | Uniform Resource Locator | +| WEEE | Waste Electrical and Electronic Equipment | + +# 5 Conventions + +Generally, ITU-T Recommendations use the term "ICT goods" instead of "ICT products", However, considering this Recommendation is about the DPP, both terms are used interchangeably. Hence the term "product" should be considered synonymous with the term "goods" in this Recommendation. + +# 6 Description and scope of the digital product passport + +For ICT products, access to digital information about a product, a DPP, enables or facilitates the activities of product operators, such as manufacturers, buyers, owners, repairers, refurbishers, recyclers, market surveillance authorities, environmental and sustainability auditors, and customs authorities. + +A DPP may provide access to digital data, such as linked data, with access to lists, datasheets, manuals and guides, that contain reliable environmental sustainability data. For instance, it can facilitate circulation (maintenance, repair, reuse, recycling tasks) by providing support information for tasks that contribute to extended use. + +Access to digital data about products can help diverse organizations exchange and aggregate data records about models and individual products to produce factual or empirical statistics about the durability of products, among other qualities and make recycling and electrical and electronic waste (e-waste) management more accountable and verifiable. The demand for public digital data can result + +in manufacturers, governments and users implementing voluntary or mandatory reporting and monitoring mechanisms to assess these qualities and become an incentive to design and use more circular ICT products and processes. + +Relevant digital information can be anything useful to a product operator, user, member of the general public or researcher into materials, design, usage, maintenance, repair, spare parts, and ways to recover and dismantle components and recycle them. That can be extended to specifications, programming, firmware and software to allow maintenance and usage, even when manufacturers stop maintenance to allow third parties to do so. + +Raw materials (including scarce critical raw materials, secondary materials) and the adverse social and environmental risks from the presence of hazardous substances, deserve special attention and require environmental responsibility from product manufacturers to monitor and inform about the social and environmental implications of their supply chain in design and manufacturing, facilitate due diligence by public procurement, as well as regarding the reverse supply chain when products may be reused or are no longer used and should be recycled and materials recovered. + +Having all this information related to sustainability and specifically about circularity in digital and standardized format can bring qualities, facilitate and improve many processes, and help citizens, organizations, and governments to assess their environmental footprints and other statistics about the digital and ICT sector. This is a central topic of the idea behind the so-called product information sheets or DPP as part of a sustainable digital transformation of society [b-ITU SDTD] [b-EC 2021]. The global harmonization of sustainability requirements can facilitate regional regulation to all stakeholders to promote circular and sustainable ICT products. + +This structured collection of product-related information, represented as digital data, can facilitate and bring transparency about design, manufacturing, use, reuse and recycling processes, such as facilitating impact assessment on the environment. A product passport can help integrate existing and new data, facilitate interoperability across different actors involved, and bring in quality properties such as transparency, traceability, verifiability, and accountability of digital products, infrastructures, and services that lead to sustainable digitalization. + +There are related initiatives and standards regarding which product information is relevant from an environmental perspective from several standards' development organizations. These are described in Appendix I. + +Different sources and viewpoints influence the design and implementation of DPP systems: + +- global environmental sustainability and circular economy (CE) opportunities raised in this Recommendation; +- regional requirements resulting from policy and regulatory choices by governmental actors in different regions; +- the self-regulation choices among the involved actors in the supply and demand of DPPs; +- results from the experience and the evolution of DPP implementations. + +A phased introduction of a DPP, driven by regional legislation or regulation by public authorities or multi-stakeholder self-regulation agreements, would enable an early introduction of core product digital information and evolution towards comprehensive information details to promote the most environmentally sustainable products. + +# 7 Circular digital products + +The scope of products in this Recommendation is digital technology products (ICT products and their components, electrical and electronic equipment, and e-waste), focusing on circular and sustainable products. + +This clause describes stages, challenges and digitalization considerations at different stages and for different actors in the CE, desirable properties of DPP data and the specification of what constitutes a product for the purposes of a DPP in terms of sustainability information. + +## 7.1 Objectives for a circular economy + +Three main objectives are recognized for the CE for electronics in [b-WEF PACE]: + +- 1) new products use more recycled and recyclable content; +- 2) products and their components are used for longer; +- 3) after the end of the use stage, products are collected and recycled to a high standard. + +These objectives translate into eco-design, circular business and ownership models, and more circular e-waste management. + +The following list gives some examples of aspects that can support taking CE into use: + +- product durability and reliability; +- product reusability; +- product upgradability, reparability, maintenance and refurbishment; +- the presence of substances of concern in products; +- product energy and resource efficiency; +- recycled content in products; +- product remanufacturing and recycling; +- carbon and environmental footprints of products; +- expected generation of waste materials from products. + +## 7.2 Lifecycle stages + +Circular digital products undergo several lifecycle stages, specified in [ITU-T L.1410] or the technically aligned [b-ETSI ES 203 199], and face challenges that the digitalization of the lifecycle information supported by a DPP can help with. + +The lifecycle stages of ICT products are grouped as goods raw material acquisition, production, use and end-of-life. They can benefit from circularity in diverse ways as follows. + +- **Raw material acquisition:** Raw material acquisition starts with extracting natural resources (e.g., iron ore, crude oil, etc.). It ends with transporting raw materials from raw materials processing to part or component production facilities [ITU-T L.1410] or the technically aligned [b-ETSI ES 203 199]. +- **Production:** Production or manufacturing starts with parts production, followed by assembly and ends with the transportation of ICT products and support products to use [ITU-T L.1410] or the technically aligned [b-ETSI ES 203 199]. +- Design and manufacturing decisions determine the use of primary materials extracted from nature and secondary materials captured from e-waste. +- **Use:** The use stage includes ICT products procurement, sale, use, reuse, repair, modification and other support activities [ITU-T L.1410] or the technically aligned [b-ETSI ES 203 199]. +- In the use stage, products can be used and transferred for reuse until they are no longer valid for that purpose. During use, products consume energy, parts can be added or replaced, and suffer from wear and tear and change during an expected long lifespan. The product warranty period, access to product repair, availability of security and software updates, access to repair instructions, repair tools and services, spare parts, consumables, the ability to detect + +counterfeit products and parts, and the ability to reuse or single-use nature make a difference in durability and quality of service. + +- **End-of-life treatment:** Such treatment starts with the collection and transport of de-installed ICT products or support products to storage, disassembly, parts reuse, dismantling and shredding facilities, and ends with the recycling of raw materials, recovery of secondary materials and final disposal of treated waste ICT and support products [ITU-T L.1410] or the technically aligned [b-ETSI ES 203 199]. + +## 7.3 Challenges in the electronics lifecycles + +Despite the push towards a CE, with an impetus to systemic improvement and awareness-raising, on-ground implementation challenges hold back more efficient and circular electronics lifecycles. These are, according to [b-ITU 2021], as follows. + +- **Insufficient and unreliable data on e-waste flows:** Such as for the determination of fair and effective regulation and policies, realistic collection targets and tailored e-waste management programmes. The Global E-waste Statistics Partnership [b-ITU GESP] helps countries compile data and statistics on e-waste flows using an internationally harmonized measurement framework. +- **Information asymmetry and limited trust:** Such as between suppliers of components, producers and recyclers on product composition, or repairers and recyclers on product components, due to concerns from producers on the confidentiality of their product information, often without mechanisms to verify the data by external parties to limit the risk of fraud. +- **Informal and unreported e-waste:** Such as when the informal sector primarily manages e-waste; regulatory obligations of the ICT products sector, especially under EPR policy schemes, require producers to have visibility over and report the sources of their raw materials and where products end up. The Basel Convention [b-UNEP Basel 1989] requires that hazardous and other wastes in its scope move transboundary by the prior informed consent (PIC) procedure, whereby every shipment should travel with a movement document and the consent of all states concerned in transboundary movement. +- **Insufficient consumer participation and appropriate end-of-life channels:** Such as returning a product to the producer or disposing of it in a municipal e-waste bin. Low worldwide collection and standard recycling rates indicate that a barrier exists. +- **Inefficient e-waste management processes:** Such as those that are costly and complicated as more ICT products are introduced to the market. +- **Insufficient cooperation between stakeholders throughout lifecycles:** E.g., installers change the original hardware configuration of the equipment during installation, users change or upgrade a product with new or altered components, repairers modify a defective product and hence change the composition of a product in use. + +## 7.4 Digitalizing information about ICT product lifecycles + +The application of digital technologies, specifically a DPP, can support the transition to a circular electronics industry, helping to address the challenges just introduced and to optimize existing solutions with digitalization, as well as enabling new transformation methods. Such application implies satisfying the needs of all stakeholders. Each actor that creates and modifies products has its own responsibility in contributing to the corresponding product information. + +A DPP enables transparency and facilitates traceability implementation in the supply chain across all actors. For instance, digital certification of legitimate parts and components, materials, actors and product tracking, can be used to create a digital chain of custody throughout the lifespan, ranging + +from primary or secondary materials to e-waste and prevention of the introduction of counterfeit elements with environmental risks [ITU-T L.1034]. + +These properties are described in more detail in clause 7.5. In terms of the lifecycle stages described previously, the benefits can be as follows. + +### **Raw material acquisition** + +The raw material acquisition stage can provide transparency and traceability by reporting details of the supply chain in terms of actors involved in material extraction or secondary (recycled) material recovery, processing and tracking, particularly the presence of critical raw materials or hazardous substances and manufacturing waste. For instance, [ITU-T L.1102] allows the communication of information about rare metals. + +### **Production** + +The production (manufacturing) stage can support transparency and traceability by reporting information coming from supply chain actors (e.g., designer, tier 2, tier 1, manufacturer) involved in parts production and assembly. In the design phase, circular design can contribute useful digital data about designed energy efficiency, durability, repairability, reusability, and recyclability. Readily accessible digital information in a DPP for that product can facilitate and even automate processes along the supply chain and product lifecycle, proving compliance with legislation, facilitating market surveillance by public authorities and customs, and supporting sustainability claims. This information will help identify and buy sustainable products. + +### **Use** + +A DPP can facilitate public procurement by providing standardized informative details, document links, verification details, ecolabels, environmental scorings and energy efficiency labels, to guide due diligence, selection and purchase, and give valuable data to keep track of products in an inventory to manage preventive maintenance and repair. + +Precise, detailed and updated product information can facilitate decisions towards increased durability through the use, upgrade, repair and reuse of parts, components or the product, provide information to enable public policies that may restrict single use or prevent the destruction of unsold products, detect premature obsolescence and incentivize servitization. + +Regarding the reuse of refurbished and remanufactured products, a DPP can help reduce uncertainty when procuring pre-owned ICT products. + +It can facilitate repair, upgrade or refurbishment (repair manuals, spare parts for users or professionals), which helps prevent unnecessary replacement. It can facilitate the collection of empirical repairability metrics, as well as the collection of actual energy consumption measurements in the use stage. + +Products with a DPP for collective products, a product model or product batch, can become unique individual product items in the use stage. Circularity and a long lifespan imply processes that modify products that make them unique. They may require product operators to produce an individual DPP that reflects these unique characteristics and changes in a unique product item over the initial model-specific DPP. + +ICT products change during the use stage due to usage, reconfiguration of modular products, repair and reconfiguration, and wear and tear that therefore lead to the possibility of dynamic data addition or item level updates for their corresponding individual DPPs. That can increase the divergence and mismatch between the DPP at the production stage and after modifications during the use stage, particularly when these changes affect the environmental performance and composition of a product. + +All these processes contribute to product life extension, combined with more circular business models, such as leasing rather than product ownership, product as a service and asset sharing, + +increasing the longevity of ICT products as they pass through several users before their end of life is reached. + +### **End-of-life treatment** + +In end-of-life treatment, the collection of products can be improved by providing information to assist in the correct return or disposal of products. Improved recycling can be achieved by having accurate information about materials and other product characteristics that can facilitate or automate triage and prevent environmental risks. Such information includes details of the selection of components to reuse or product remanufacturing, improvements in sorting and pre-treatment of waste to extract secondary materials, treatment and prevention of harm to people and nature from the presence of hazardous substances. + +Digitalization supports transition of informal sector workers to the formal system by building capacity and introducing more transparency and accountability with business opportunities that enable social innovation. Specifically, precise and reliable data can help optimize and automate e-waste sorting, dismantling and recycling. + +Digital data can facilitate the creation of marketplaces for e-waste, materials and pre-owned products throughout the product life: with platforms for traceable and transparent transactions for e-waste and secondary resources, enabling informal sector integration and mainstreaming. This transparency can inform and facilitate the implementation of public policies to prevent the destruction of unsold or still usable (and reusable) consumer products, or transborder movements of e-waste, which are environmental problems. + +Convenient, incentivized, and optimized e-waste collection and takeback help transfer incentives to consumers to dispose of waste responsibly in return for digital rewards. EPR schemes can involve manufacturers in a more efficient, informed and accountable way. + +### **Market surveillance** + +Authorities in charge of market surveillance or customs authorities should get precise digital information about source attribution for all DPP-covered products in a market: unique product identifiers (IDs; what), unique operator IDs (who), unique facility IDs (where), and additional information, such as information about and verification of regulatory compliance, when relevant and according to regional laws and regulations. Authorities need to interact with the DPP system that represents the market, to verify correctness of product information. + +### **On collecting and maintaining product information** + +Digital standardized and linked information allows and provides the details required to assess the sustainability impact of ICT products and their supply chain. Specifically, it can bring several benefits as follows. + +- **Facilitation of knowledge generation throughout the product life:** Feeding databases and datasets for data integration and analysis, and compliance with national or regional regulations about the right to reuse and repair. +- **Reduced paperwork and administrative burden:** Digitalization can help streamline administrative aspects of the electronics lifecycle in addition to the direct benefits, such as reducing paperwork, record-keeping effort and human error, as well as provision of digitized ways to report product conformity, digitization efforts in the e-waste management sector will improve the accessibility of practical information in that field. +- **The digitalization of information:** Necessary to comply with the PIC procedure for transboundary movements of e-waste under the Basel Convention. In its 2022-2023 Workplan, the Basel Convention Parties established a working group to explore electronic approaches to notification and movement documents [b-UNEP Basel 2021]. + +- **Creating a digital chain of e-waste custody:** Integration of multiple layers of logistics, administration and approval processes to go into an efficient and effective e-waste management system; digitalization and automation of operations to provide a credible chain of custody, manage inventories, issue recycling certificates, financial calculations, settlements and report creation for compliance purposes. +- **Making monitoring and enforcement more efficient:** Virtual monitoring and auditing processes. Audits, previously carried out in person, are now conducted virtually. Sustainable Electronics Recycling International (SERI) provides advisories for the necessary checks and balances to conduct remote audits [b-SERI]. These digital audits are also helping auditors overcome the stress of continuous physical audits [b-Leif]. +- **Building capacity and creating awareness:** Provision of information to inculcate a positive attitude towards circularity. +- **Promotion of the reduction of carbon and environmental footprints:** By providing impact-related information and linking incentives to sustainability performance levels. +- These improvements rely on agreements to identify relevant data and access to it. + +This information should protect personal data privacy and business data confidentiality, as well as ensuring credibility and usefulness. These desirable data quality properties are described in clause 7.5. + +## 7.5 Desirable properties of product information + +In the context of access to environmental information, following what the Aarhus convention [b-UNECE Aarhus], the Escazu agreement [b-UNECLAC Escazu] or EU directive 2003/4/EC [b-EU 2003] recognize, the quality properties described as follows render environmental and sustainability-related information useful and reliable at the product level and in aggregate terms for statistical purposes. + +Among the desirable principles, product information shall implement measures to apply the following. + +- **Digitalization:** Beyond creating a digital representation, this refers to the enabled changes, usually optimization and improvement activities. +- **Data findability, accessibility, interoperability and reusability:** Are commonly referred to as findable, accessible, interoperable and reusable (FAIR) principles. [b-Wilkinson] +- **Usefulness:** Fit for purpose, avoiding unneeded information. +- **Accuracy:** Correct, precise, according to fact; bringing clarity, avoiding vague and confusing information. +- **Inclusivity:** Limited or progressive complexity and cost to prevent excluding small economic actors. +- **Transparency:** Clarity is a need to trust and scale up circular processes. +- **Accountability:** A key to answerability, liability, and the expectation of account reporting, and linked to past and future actions. +- **Standardization:** This can help to maximize compatibility, interoperability, quality, repeatability or quality. Harmonization can facilitate standardization of customs processes across national or regional boundaries. +- **Information privacy:** This is the relationship between the collection and dissemination of data, and privacy protection of the subjects involved. +- **Information protection:** Respect and protection of intellectual property and business confidentiality. + +Among the data quality properties, provision of guarantees to ensure that bad things do not happen shall implement measures to apply the following. + +- **Accessibility:** Although the ability to facilitate access and benefit from information on a need basis to a broad range of actors and situations may be helpful, some information may require or benefit from restricted access (e.g., industrial and trade secrets, personal privacy, business confidentiality) according to the needs and profiles of the actors involved, or appear in summarized information (e.g., yes/no answers to questions as on a product circularity data sheet (PCDS)). +- **Free access to relevant information:** In the DPP of a product is needed by consumers (i.e., anyone in the general public) for informed purchases and use. This also raises the need to present information consumers can understand, which can be met by appropriate presentation (e.g., user friendly, in the local language). +- **Persistency:** Accessibility in terms of the longevity of accessibility to information, related to the expected longevity of products (durability). +- **Authenticity:** The ability to prove an assertion and the identity and authentication of actors involved helps ensure digital information has an accurate and representative value. +- **Identifiability:** Authenticity as it applies to prove the matching to the corresponding product. +- **Composability:** Linked data is vital for products composed of components and materials in products that are transformed and reconfigured during their lifespan. +- **Integrity:** Maintaining data accuracy and consistency over the entire lifecycle of a product is vital for a CE. Data carriers can reduce manual data entry errors, and internal software in ICT products can report internal data directly to the DPP (i.e., digital twin) to ensure information integrity. +- **Verifiability:** Allows a way to confirm the veracity of assertions about sustainability and circularity. This can be implemented through third-party verification schemes, digital signatures (it identifies information sources, and non-repudiation, and can determine integrity or alteration) and (links to) documents. +- **Traceability (of products):** Tracking and tracing are essential for a responsible CE, following individual product items and flows along supply chains. Digital linked data and IDs for products and actors can facilitate traceability throughout the lifecycle. + +Digitalized information enables accessibility, contributing to the clarity (transparency) of the electronics or ICT sector and its users and monitors. That clarity relies on accuracy and maintenance to assure information integrity. Information should have the property of being accurate and valid. Confidence in the validity of information leads to the quality of being verifiable, supported by documented facts. Verifiability enables accountability, the ability to answer, an enabling attribute to support access to environmental information in line with what international agreements recognize about environmental information quality. In fact, verifiability and accountability enable the prevention of greenwashing, the avoidance of vague, unfounded, unsubstantiated claims, and are dependent on clarity and accuracy. + +DPPs are enablers to the ability to track and trace product flows (e.g., products, components, materials, e-waste) after the product has been placed on the market. Tracing allows for verification of the aftermarket history of an item, status, location or components using documented recorded identification, determination of the origin, composition, and actors involved and deducting from that repair or end-of-life handling possibilities. Tracking reveals what happened to a product after it was placed on the market and in the future, which is helpful for impact assessment and reporting. Since aftermarket repair and enhancement of products rely on components and materials that can change over the lifespan of products and components, these relationships lead to the requirement for data composability, as linked data that can change by linking as the related material element changes over its circular life. + +Complete traceability information is unfeasible as it encodes digital data and every detail of every input. Details are relevant according to the system's objectives. There are differences to consider in the breadth, depth, and precision of traceability systems [b-Golan]. [b-KEEP] adds access and latency (speed), both applicable to DPP and traceability applications as follows. + +- **Breadth** (level of detail) describes the amount of information the digital system records. Breadth can range from high (many) to low (few, including product ID). +- **Depth** of the system is how far back or forward in time the system tracks. Depth can range from high (e.g., from raw materials acquisition) to lower (e.g., from production). +- **Precision** (granularity) reflects the degree of assurance that a system can pinpoint a particular product or those with common characteristics. Precision can range from high (individual product items, components or parts) to low (batches or models). +- **Access** refers to the number of different parties with full or partial access to product and process data. Access can range from high (economic and product operators such as suppliers, customers, users, regulators or legislators) to low (owners only). +- **Latency** (change) is the length of time it takes between parties to share and update product information. It can range from instantly, the moment it happens, to slow (eventually) to out of date (already changed again). + +In summary, standardized ways should be provided to share linked data about all related participants and items (traceable) related to specifications (design), materials, parts, products, flows (as business processes), decisions with outcomes (e.g., production, sale or purchase, transfer, disposition). This data should be in digital form, accessible and transparent (transparency) to the relevant actors, trustworthy (integrity, verifiability) and detailed (composable, traceable) to facilitate informed and efficient decision-making, action, scaling up to the global market and the assessment of impacts. + +Regarding accuracy, while some environmental information in ICT products would remain static (unchanged), other information changes during a lifespan as the product changes to keep it precise and up-to-date (latency). The two categories of attributes have the following issues to consider. + +- Static attributes are product information required at the moment of placement on the market, remaining stable over the product lifetime. Static attributes can be applied at the model level and are the manufacturer's responsibility. They serve mainly for purchasing decisions, not CE activities. + +Examples of static attributes include the model ID, the reparability score, dismantling information, estimated energy consumption and environmental footprint information, including when new spare parts are integrated. + +- Dynamic attributes are modifiable product details that remanufacturers, refurbishers and repairers can change as they perform CE activities. + +Examples of these attributes are changes in critical raw material information or updates to the percentage of recycled content resulting from integrating spare parts with differing specifications from the original part. + +For the dynamic attributes to remain correct during the entire lifecycle of a product, DPPs should cope with the following issues. + +- CE actors have to ensure accurate DPP updates when there are changes in a product. +- It is very burdensome for CE actors and consumers to host DPP records and assume product liability for information requirements. +- Market surveillance authorities need to expand their capabilities to enforce and verify compliance with timely updates of the dynamic attributes by independent repairers. +- There may be a large energy usage implication from a jump in data storage needs in cases when model- or batch-based DPPs are replaced by individual DPPs. + +- Economic and product operators, the market, need a learning period to fully understand and build on the DPP potential. + +Regarding accessibility and longevity (persistence), information can be encoded as data placed by the following methods. + +- **In a data carrier on the product:** Very accessible but limited data storage space depending on the different label method types (e.g., one and two-dimensional codes), with priority for product and actor identification, and for risks (e.g., presence of substances of concern) and value (e.g., presence of rare metals [ITU-T L.1102], digital or uniform resource locator (URL) link to retrieve further information). Longevity, as long as it is readable, equal to the product, but updates typically require data carrier replacement. +- **Inside the product or packaging:** In a non-volatile medium inside (internal storage) or outside the product (external storage such as a pen drive). Longevity, as long as it is readable, updates require local data file updates, as long as the medium allows. +- **Online:** Through a web link (e.g., GS1 digital link [b-GS1DL]) obtained from a data carrier. Longevity, as long as it is provided with updates by the data provider. + +The choices depend on the technical limitations of the different storage options, the dimensions and capabilities of physical products in their ability to incorporate a data carrier, legislation in different regions, as well as self-regulation and preferences of manufacturers. However, online information needs to be accessible (a URL that resolves into the data required) for a period that matches the expected durability of the product (considering a circular lifespan with reuse). + +## 7.6 Definition of the product + +What the product is in the context of electronics and ICT products has to do with the required or recommended level of detail in terms of breadth, precision or granularity of identification. A DPP shall refer to the following non-exhaustive list of product types. + +- **Individual ICT product:** Such as a serialized or customized individual ICT product item. +- **Collective ICT product:** An ICT product batch or model with common characteristics for multiple product items. +- **Modular ICT product:** An ICT product that combines a container product (e.g., rack, chassis) with included modules (ICT products) that can easily be replaced or added. +- **Replaceable parts (products):** Such as batteries, display modules, or consumables like print cartridges. +- **Accessory products:** Such as cables and keyboards. + +Choices on breadth, precision or granularity depend on product characteristics and agreements across actors about the level of detail to report in a DPP. + +The product scope of DPP has considerable implications for the DPP architecture and implementation. Alternatives are discussed and compared in clause 8. + +### 7.6.1 Classes of products (verticals) + +Some characteristics are specific to ICT product classes (verticals) with specific environmental requirements for function or form (components). Some examples of product categories follow. + +- **Electric and autonomous vehicles:** Have large batteries and many critical ICT elements (products), with specific environmental and personal safety requirements. +- **Smartphones:** With mobility requirements and smaller batteries and electromagnetic emissions. +- **Computers:** With diverse characteristics and product ranges. + +- **Displays:** With the potential presence of lead in cathode ray tube monitors [b-Macauley] or mercury in liquid crystal displays [b-Elo], among others. +- **Office equipment:** Including fax machines, laser printers, ink-jet printers, scanners and photocopying machines), with serious potential environmental risks to human health from the concentration of volatile organic compounds, ozone and respirable particles (PM10) [b-Lee]. +- **Network products:** With diverse characteristics and product ranges. + +These verticals are not covered in the specific details in this Recommendation. + +### 7.6.2 Customization and change + +While new or remanufactured consumer or industrial ICT products are produced in large quantities with identical features, therefore represented by a DPP in common, customized (modified) products (as a result of reconfiguration, repair, refurbishment, incorporating new, modified or second-hand pieces) tend to acquire unique environmental characteristics and may require individual DPPs to accurately reflect them. + +The details about the sustainability of products in a DPP can be fixed at different times as follows. + +- A model passport may be fixed at design time (at product launch). +- A product batch passport may be fixed at manufacturing time. +- Changes during the lifespan affect one or a few product item units, not all. Environmentally sensitive changes may require individualized DPPs that extend or replace the DPP for the product model or batch (as a supplement, complement or specific variant of the previous or collective DPP). + +NOTE – Changes are linked to the previous DPP for traceability. The degree of change is related to latency as described in clause 7.5. + +A decentralized approach would allow a new passport or supplement to be created and linked to its predecessor every time the information changes due to modifications made by the product operator that has specific information to report, and attached to a data carrier in the product or registered in a decentralized search or lookup service for serialized or unique products. + +#### 7.6.3 Relevant details to sustainability + +Consideration of a circular lifespan of products results in the need to report information related to or resulting from processes, ranging from raw material acquisition, manufacturing, usage, servitization, transfer, maintenance, repair, refurbishing, remanufacturing, disassembly, recycling and recovery (related to [b-ITU-T L-Suppl.28]). Such consideration results in a collection of relevant information, affected and extended by these processes, with details in Appendix I as far as sustainability-related standards and databases are concerned. However, design decisions result in many relevant informative details as introduced by clause 7.1 of this Recommendation, in line with the details described in [ITU-T L.1023]. + +# 8 Guidance for implementation + +This Recommendation, which is global and broad (generic), presents an overview from an environmental perspective (sustainability) of the digitalization of product-related information integrated and harmonized under a DPP representation. + +DPPs are expected to incorporate data in response to demand from ICT service providers, product operators, consumers and sector regulatory authorities. DPPs can be linked and provide information about compliance with regulations and standards: such as requirements, responsibility, support, verifiability, audit, traceability and transparency, that can be checked digitally. That arrangement + +should benefit all stakeholders and reduce the burden of taking informed decisions to optimize and assess the sustainability of ICT products. + +Specific product categories, regions, governments, industries and citizens (stakeholder groups) may raise additional requirements from sustainability and other perspectives, so DPPs are expected to evolve in terms of refinement and harmonization, similarly to the way other global public information systems have evolved. Discussion, consensus, standardization and legislative processes on these can enable agreements to develop concrete and specific DPP specifications, including required and voluntary (recommended or optional) values, static and dynamic. This can be achieved according to existing standards, public regulations and industrial self-regulation, to deliver all digital data that can help achieve more sustainable ICT products due to the efficiencies and savings from digitalization of product information. + +However, there are two aspects of DPP from a circularity perspective as follows. + +- **Collective: product model or batch.** Manufacturers and importers, as economic operators introducing industrial, professional or consumer products to the market, are the informed and responsible actors to produce DPPs for new or remanufactured ICT products in volume, which can be found from a data carrier in the product itself. All product items in a given batch or model usually share the same reported characteristics and can therefore share the same DPP. The economic operator introducing a product to the market can publish and even update that DPP information (versioning) in their website to allow anyone to read the data carrier on the product, find and access that DPP document, with informative details and links to the latest related informative and verification details, and with content that can be customized to the needs and profile or credentials of the visitor. + +These DPPs can be updated to reflect improved or localized information (specific details or in local languages of a region), the effect of software updates and adaptation to comply with changing or different regulations for products already on the market. + +- **Individual: product item.** Product operators in the CE can modify individual product items and, therefore, their environmental information. Product items get modified through repair, reconfiguration, refurbishment and recycling. Given their knowledge about the details of product item modifications, they can issue a new DPP for that modified product item that refines, updates or complements the original collective (e.g., model based) DPP. A DPP for a new product item should relate to the previous or initial (model or batch, collective) DPP. The new DPP may be found by either attaching a new data carrier to the product item or by a model+serial unique number lookup in a public searchable DPP repository. + +These individual DPPs, precise to the environmental characteristics and performance of the product item, with verifiable information linked to public databases and digital ledgers, precisely identifying the economic and product operators and third parties involved, increase trust in the DPP information by users of modified (repaired, reconfigured or refurbished) second-hand products and helps the final recycler to manage e-waste according to the latest product item characteristics at end of life, which may differ significantly from those just after manufacture. Reliable and accurate DPPs are key to facilitating the development of a CE of long-lasting ICT products and increasing the circularity supported by safe (precise, reliable, etc.) environmental sustainability information while reducing processing costs, and increasing scale and quality or accuracy in product processing. + +Therefore, DPP information can be corrected, and extended by responsible actors that can provide information meeting the desirable quality properties in clause 7.5. However, product information changes for an unmodified material product (versioning) differ from those for product modification or customization, usually done for individual items, which can require an individual DPP issued by the product operator that modified the product, with its corresponding data carrier attached to the product. + +DPPs should be available on a product item or the Internet for a long enough period (retention period), at least covering the time a product can be on the market and reach recyclers. This means content should not be hosted on the economic or website of the product operator alone. + +In addition to providing informative product details, specifically about environmental sustainability, a DPP can also include details of the quality of information to validate claims made by diverse product operators in the CE market. + +## 8.1 DPP architecture considerations + +The product-level scope of DPP has considerable implications for the DPP architecture and implementation. Alternatives are compared in Table 1. + +**Table 1 – Impact of the product-level scope of DPP architecture** + +| Comparison item | Product-level scope of DPP | | | | +|--------------------------------------------------------------------|----------------------------|----------------------------|----------------------------|------------------------------------------------------| +| | Brand | Product model (collective) | Product batch (collective) | Individual product item | +| Creator or maintainer of DPP and the data, see Note 1 | Manufacturer | Manufacturer | Manufacturer | Manufacturer or third party | +| Third party horizontal infrastructure to maintain DPPs, see Note 2 | – | – | – | Infrastructure capability rollout needed, see Note 3 | +| Basis of DPP identity | Brand ID | Model ID | Batch ID | Serial number | +| Track passport versions forwards or backwards, see Note 4 | – | OK | OK | Implementation open, see Note 5 | +| DPP data and data transaction volume, see Note 6 | Lowest | Low | Low or medium | High | + +NOTE 1 – 'Maintain' refers to either DPP editing capability or the capability to create an updated version or a DPP supplement. It can also refer to maintaining a DPP data delivery service. + +NOTE 2 – If the manufacturer creates a DPP, it can be read-only for other actors, who can start using it at will. This differs from a large-scale horizontal or product-item DPP with maintenance, updating or editing capability for relevant actors. + +NOTE 3 – This involves the formulation of several implementation and data security-related questions, see discussion in Notes 5 and 6. + +NOTE 4 – This row assumes that model- or batch-based product passports are maintained by the manufacturer, as it might be somewhat difficult to justify other approaches. When manufacturers maintain the data, the solution architecture is still distributed since each manufacturer maintains their own data. In that case, it is also easy to arrange the linking of different passport versions, both backwards and forwards. + +NOTE 5 – If each individual product item has its own passport so that third party upgrade or repair services need to produce a new revised passport, they have to have either editing rights to the manufacturer's data (which can be problematic in many ways), or to establish their own data. In the latter case, the passport history of a product can be obtained by searching all passport versions on a web service having links to information about the product ID and economic or product operator placing the product on the market. If the manufacturer desires to analyse the events in the life of a product, then forward tracking of passport versions may be very difficult in this type of scenario. + +NOTE 6 – Volume has an implied impact on data storage, data processing and energy consumption. In the worst case, this may even compromise getting any net benefits from DPP (See Appendix II). + +## Appendix I + +### Related work, standards and data sources concerning environmental sustainability + +(This appendix does not form an integral part of this Recommendation.) + +### I.1 Related work + +A DPP relates to existing available data formats, linked data, wire and storage data formats and system architectures, as well as being complementary to upcoming initiatives that are regional (e.g., European DPP) and global (ISO PCDS [b-ISO 59040], [b-IEC 82474-1]) specifications and standards. Integration and standardization with a global scope aiming at reducing the burden of already providing partial information through multiple specific and regional standards. + +This Recommendation considers ICT products classified according to [ITU-T L.1023] on an assessment method for circular scoring by facilitating data collection that can show the effect of a design decision in practice. It can help collect details as data records along the lifespan of ICT products to assess and report impacts of circular business models as in [b-ITU-T L.1024], about servitization: selling services instead of equipment. It can facilitate the calculation of lifecycle environmental impacts of different ICT products according to the ITU-T L.1400 to [b-ITU-T 1451] and mobile phones according to [b-ITU-T L.1015]. These and more are listed in more detail in clause I.2. + +### I.2 Standards and data sources related to sustainability + +International standards provide guidance and the framework to implement circularity across the electronics lifecycle. The aim is to collect opportunities from existing standards about valuable details represented in a DPP. + +Table I.1 presents ITU-T recommendations according to the main stages of a circular lifecycle, introduced in clause 7.2. + +**Table I.1 – ITU-T Recommendations according to lifecycle stages** + +| Raw material acquisition and production | Use | End-of-life treatment | Other sustainability – related Recommendations | +|---------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------|-----------------------------------------------------|----------------------------------------------------------------------| +| Green batteries for hand-held devices [b-ITU-T L.1010] | Servitization [b-ITU-T L.1024] | Sustainable e-waste management [b-ITU-T L.1021] | ID tag requirements [b-ITU-T L.361] | +| Assessment of circular scoring [ITU-T L.1023] | Circular public procurement [b-ITU-T L.1061] | E-waste management for countries [b-ITU-T L.1030] | Criteria evaluation environmental impact of mobiles [ITU-T L.1015] | +| Methodology to identify key equipment for environmental impact and e- waste generation assessment of network architectures [b-ITU.T L.1050] | | Certification of e-waste recyclers [b-ITU-T L.1032] | Material efficiency and circular economy definition [b-ITU-T L.1022] | + +**Table I.1 – ITU-T Recommendations according to lifecycle stages** + +| Raw material acquisition and production | Use | End-of-life treatment | Other sustainability – related Recommendations | +|-----------------------------------------------------------------------------------------|---------------------------------------------------|---------------------------------------------------|-------------------------------------------------------| +| Printed labels for communicating information on rare metals in ICT goods [ITU-T L.1102] | | Recycling rare metals [b-ITU-T L.1100] | Environmental impact assessment [b-ITU-T L.1400] | +| | | E-waste reduction targets [b-ITU-T L.1031] | | +| Methodology for environmental life cycle assessments (LCAs) [ITU-T L.1410] | Methodology for environmental LCAs [ITU-T L.1410] | Methodology for environmental LCAs [ITU-T L.1410] | | + +[ITU-T L.1410] or the technically aligned [b-ETSI ES 203 199] provides a methodology for environmental LCAs of ICT goods, networks and services, for the environmental assessment of the lifecycle impact of ICT goods, networks and services. Data should be collected for all mandatory processes. The collected data, whether measured, calculated or estimated, are utilized to quantify the inputs and outputs. + +[ITU-T L.1023] outlines the circularity aspects and indicators for circular product design of relevance for circular ICT. + +The ITU-T L.1023 methodology translates into guidance for the identification of the margin of improvement level for each indicator. The detailed table brings specific digitalized details required for scoring (yes/no questions in the style of a PCDS) and supporting information. + +The PCDS [b-PCDS 2020][b-PCDS 2023][b-ISO 59040] is an initiative that provides a public specification for suppliers of materials and semi-finished products to provide verifiable information about the circularity properties of their materials. It is inspired by the (material) safety data sheet [b-UNECE SDS], which chemicals suppliers use to provide safety information about their substances and mixtures. The PCDS offers a standardized format with trustful data without scoring or ranking these aspects. There is a third-party verification process to validate the content (audit) and a data exchange protocol to be specified separately. It has three objectives: to provide basic data on materials circularity; improve the sharing efficiency of circularity data; and encourage the circularity performance of products. A new PCDS can be created at each stage of the material transformation process. The material supplier passes their PCDS one step up the supply chain to allow for its integration into the material transformation process of the next tier. Each material manufacturer is responsible for storing the information related to PCDS statements and making such information accessible to other stakeholders upon request. A PCDS is designed to be integrated through the supply chain. Given its aim, PCDS constitutes a good generic circularity information source for a DPP. + +There are information and data sources (databases, lists, registries, codes) agreed in the scope of regional and global conventions that provide details about agreements on substances, materials, labelling and identification of national, regional or global scope, that can be referenced in a DPP as follows. + +- The globally harmonized system [b-UNECE GHS] for classification and labelling: categories, symbols and risk phrases for hazardous substances. + +NOTE – GHS can be used to determine the relative hazardousness of substances and compounds [b-Andrae 2020b]. + +- UN Numbers for hazardous substances [b-UN 2019]. +- Hazardous substances and materials SDSs [b-UNECE SDS]. +- Harmonized systems codes for trade categories of products and e-waste, issued by the World Customs Organization [b-WCO HS]. +- Basel Convention codes [b-UN Basel 2023]. +- Transport codes ([b-UNECE ADR], International Civil Aviation Organization (ICAO) etc.). +- Schemes for classification and labelling of raw and secondary materials. +- product conformity database [b-ITU PCD]. +- Traceability registries. + +**Table I.2 – Information and data sources on regional and global environmental agreements** + +| Description | Full name | Region | Description | +|----------------------------------|-----------------------------------------------------------------------------------------------------|---------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Globally harmonized system (GHS) | Globally harmonized system of classification and labelling of chemicals international [b-UNECE GHS] | Global | The GHS includes the following elements:
a) harmonized criteria for classifying substances and mixtures according to their health, environmental and physical hazards; and
b) harmonized hazard communication elements, including requirements for labelling and safety data sheets. | +| Harmonized system (HS) codes | Harmonized commodity description and coding systems [b-WCO HS] | Global | The harmonized system (HS) is an international nomenclature for the classification of products. It allows participating countries to classify traded products on a common basis for customs purposes. At the international level, the HS for classifying products is a six-digit code system. | + +**Table I.2 – Information and data sources on regional and global environmental agreements** + +| Description | Full name | Region | Description | +|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| UN Numbers | UN numbers are assigned by the United Nations Committee of Experts on the Transport of Dangerous Goods. | Global | UN numbers or UN IDs are four-digit numbers that identify dangerous products, hazardous substances and articles (such as explosives, flammable liquids, toxic substances, etc.) in the framework of international transport. | +| Transport codes and requirements (ADR), RID and International Civil Aviation Organization/ International Air Transport Association (ICAO/IATA) delivery and global solutions) | Agreement concerning the international carriage of dangerous goods by road [b-UNECE ADR]:
Regulations concerning the international carriage of dangerous goods by rail [b-OTIF RID]:
Dangerous goods regulations [b-ICAO/IATA DGR]: | UNECE region and global | Regulations including transport codes, hazard classification symbols, packaging instructions and safety data sheets for the different means of transport (road, train and air). | +| SDS | Safety data sheet [b-UNECE SDS] | Global | | +| ITU PCD | Product conformity database [b-ITU PCD] | Global | Result of the ITU programme to enhance conformity and interoperability of ICT products implementing ITU Recommendations or part thereof. | +| SCIP | Database for information on substances of concern in articles as such or in complex objects (products) [b-ECHA SCIP] | EU | | +| ECHA-Candidate list | Candidate list of substances of very high concern for authorization [b-ECHA SVHC] | European Union | | +| ECHA-Authorization list | Authorization list [b-ECHA AL] | European Union | | +| EPREL | European product registry for energy labelling [b-EC EPREL] | European Union | | +| HMIS | Hazardous materials identification system [b-ACA HMIS] | USA | | +| WHMIS | Workplace hazardous materials information system [b-CA WHMIS] | Canada | | +| Directive 67/548/EEC and the related amendment | European hazard symbols from Dangerous Substances [b-EU 2008] | European Union | | + +## Appendix II + +### A simple estimate of the volume of data and transactions + +(This appendix does not form an integral part of this Recommendation.) + +ITU estimates [b-ITU 2023] that in 2023, 67% of the global population, or 5.4 billion people, are using the Internet. In Europe, this percentage goes up to 90.5%, which means 621 million people. + +Regarding ICT products, [b-GSMA 2023] has global estimates of 5.2 billion active individual products in 2020, with a forecasted 5.7 billion in 2025. That translates for Europe to 472 million in 2020, with a forecast of 480 million in 2025. Forecast of shipments of ICT products [b-Andrae 2020a] estimates more than 100 million desktops, 350 million laptops, and 780 million customer routers in the coming years, representing 1.23 billion individual products. Regarding the yearly sale of smartphones, [b-Statista] estimates 1.5 billion sold globally. [b-Cordella] reports a durability range of 3-5 years for these smartphones, with typically one battery change (i.e., battery issues after use periods of 2-3 years). + +Regarding relevant details about a digital product that might be reflected in a DPP, a proposal from the Luxembourg government [b-PCDS 2023] considers hundreds of statements (data items). Some of these items may require references to external data, like documentation, certificates, and databases such as those about hazardous substances. A rough working assumption about the volume of data per item is around 1 kB. + +Regarding relevant events along with lifespan, these relate to processes, design decisions, and the supply chain, which in manufacturing typically includes tier 2, tier 1, and production/assembly steps, then distribution, sale and use by a customer, and final recycling, considering a circular lifespan [b-APC]. The manufacturing phase can produce secondary materials (industrial mining). The use phase can be further detailed, including update, repair, upgrade, end-of-use, refurbishment, product reuse, reuse of their parts, recycling, and secondary material extraction (urban mining). All that translates into about 17 different processes that may affect a product and its related digital data. + +Products are in different phases of their lifespan, with a rate of change probably significant during the manufacturing phase and the recycling phase and then slowly changing over years (e.g., one or two changes of battery during an extended lifespan, one repair, one or two cycles of reuse, until final recycling). A rough estimate of the change volume is around one event per each process during lifespan. + +The volume of direct data that may represent a DPP may be estimated considering all the products available in different stages of their lifespan in a year, in the range of 1.5 billion smartphones + 1.23 billion computer and networking products sold every year, multiplied by 4 years of average durability, multiplied by 1 kB. That results in roughly 11 TB of data if every single product in the world adopts a DPP. + +Looking at the number of transactions associated with any relevant event or changes to the record. That can be estimated to be equivalent to 2.73 billion products sold yearly multiplied by 17 events over their total lifespan (assuming the imprecise simplification that these events are spread uniformly). That results in roughly 46 billion transactions per year or 1 471 transactions per second (TPS) if every product item (individual) in the world adopts a DPP to record changes in every step of its extended lifespan. + +However, if the number of transactions per item (e.g., serial number) is reduced to the minimum of manufacturing and recycling of each item, the rate reduces to 167 TPS. 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Data.* **3**, 160018. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects 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logo](0538daaa5583c23e17db3a12f2281a55_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue circular emblem with a stylized globe and the letters 'ITU' in white. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +## **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|--------------------------------------------------------|--------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +## Recommendation ITU-T L.109 + +# Construction of optical/metallic hybrid cables + +## Summary + +Recommendation ITU-T L.109 describes cable construction and provides guidance for the use of optical/metallic hybrid cables, which contains both optical fibres and metallic wires for telecommunication and/or power feeding. Technical requirements may differ according to the installation environment. Environmental issues and test methods for cable characteristics are described in other L-series Recommendations. + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|------------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.109/L.60 | 2004-09-06 | 6 | 11.1002/1000/7394 | +| 2.0 | ITU-T L.109 | 2018-11-29 | 15 | 11.1002/1000/13785 | +| 3.0 | ITU-T L.109 | 2024-01-13 | 15 | 11.1002/1000/15807 | + +## Keywords + +Cables, DAS, FTTA, hybrid cable, optical/metallic hybrid cable. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2024 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|--------------|--------------------------------------------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 3 | +| 3.1 | Terms defined elsewhere ..... | 3 | +| 3.2 | Terms defined in this Recommendation ..... | 3 | +| 4 | Abbreviations and acronyms ..... | 3 | +| 5 | Conventions ..... | 3 | +| 6 | Optical/metallic hybrid cable construction ..... | 3 | +| 6.1 | Characteristics of each medium..... | 4 | +| 6.2 | Cable element ..... | 5 | +| 6.3 | Mechanical characteristics..... | 8 | +| 6.4 | Environmental conditions..... | 8 | +| 6.5 | Fire safety ..... | 8 | +| 6.6 | Electrical characteristics and electromagnetic compatibility ..... | 8 | +| 7 | Test methods ..... | 8 | +| 7.1 | Mechanical test methods ..... | 8 | +| 7.2 | Environmental test methods ..... | 8 | +| 7.3 | Cable element test methods ..... | 8 | +| 7.4 | Electrical characteristic test methods ..... | 8 | +| 7.5 | Transmission characteristic test methods ..... | 9 | +| 7.6 | Electromagnetic compatibility..... | 9 | +| Appendix I | – Chinese experience ..... | 10 | +| I.1 | Introduction ..... | 10 | +| I.2 | Cable structure..... | 10 | +| I.3 | Requirements..... | 11 | +| Appendix II | – Chinese experience on hybrid cable for mobile communications in an access network ..... | 14 | +| II.1 | Introduction ..... | 14 | +| II.2 | Background to the distributed base station..... | 14 | +| II.3 | The integrated solution of distributed base station via DC centralized remote power supply ..... | 16 | +| II.4 | Conclusion ..... | 20 | +| Appendix III | – French/Polish experience ..... | 21 | +| III.1 | Introduction ..... | 21 | +| III.2 | Cable design ..... | 21 | +| Appendix IV | – Swiss experience ..... | 23 | +| IV.1 | Introduction ..... | 23 | +| IV.2 | Cable design ..... | 23 | + +| | Page | +|---------------------------|------| +| IV.3    Application ..... | 23 | +| IV.4    Conclusion..... | 24 | +| Bibliography..... | 25 | + +# Construction of optical/metallic hybrid cables + +# 1 Scope + +This Recommendation describes cables containing both optical fibres and metallic wires and covers the following aspects. + +- Optical/metallic hybrid cables for communications systems; +- Construction of optical/metallic hybrid cables. The optical fibre dimensional and transmission characteristics should comply with [ITU-T G.652], [ITU-T G.653], [ITU-T G.654], [ITU-T G.655], [ITU-T G.656], [ITU-T G.657] and [IEC 60793-2-10]. Dimensional and transmission characteristics of metallic wires and coaxial units for telecommunication applications and systems should comply with [b-ITU-T TR-OFCS]; +- Cables designed for outdoor, indoor, or indoor-outdoor use: fibre-to-the-antenna (FTTA) or distributed antenna systems (DAS) cables are examples of such hybrid cables; +- Cables for limited powering applications found in communications systems. +- A recommendation that an optical/metallic hybrid cable should be provided with cable-end sealing and protection during cable delivery and storage, as is usual for metallic or optical cables. If splicing components have been factory installed, they should be adequately protected; +- A recommendation that pulling devices can be fitted to the end of the cable if required. + +Three types of optical/metallic hybrid cable are considered in this Recommendation according to the usage of the metallic wires, such as Type I: communication only, Type II: power feeding only, and Type III: both power feeding and communication. + +Individual requirements for Type II optical/metallic hybrid cable which supports a bit rate up to 1 Gb/s or beyond can be found in [ITU-T L.109.1]. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T G.650.1] Recommendation ITU-T G.650.1 (2024), *Definitions and test methods for linear, deterministic attributes of single-mode fibre and cable*. +- [ITU-T G.650.2] Recommendation ITU-T G.650.2 (2015), *Definitions and test methods for statistical and non-linear related attributes of single-mode fibre and cable*. +- [ITU-T G.652] Recommendation ITU-T G.652 (2016), *Characteristics of a single-mode optical fibre and cable*. +- [ITU-T G.653] Recommendation ITU-T G.653 (2010), *Characteristics of a dispersion-shifted, single-mode optical fibre and cable*. +- [ITU-T G.654] Recommendation ITU-T G.654 (2020), *Characteristics of a cut-off shifted single-mode optical fibre and cable*. + +- [ITU-T G.655] Recommendation ITU-T G.655 (2009), *Characteristics of a non-zero dispersion-shifted single-mode optical fibre and cable.* +- [ITU-T G.656] Recommendation ITU-T G.656 (2010), *Characteristics of a fibre and cable with non-zero dispersion for wideband optical transport.* +- [ITU-T G.657] Recommendation ITU-T G.657 (2016), *Characteristics of a bending-loss insensitive single-mode optical fibre and cable.* +- [ITU-T L.100] Recommendation ITU-T L.100/L.10 (2024), *Optical fibre cables for duct and tunnel application.* +- [ITU-T L.101] Recommendation ITU-T L.101/L.43 (2015), *Optical fibre cables for buried application.* +- [ITU-T L.102] Recommendation ITU-T L.102/L.26 (2015), *Optical fibre cables for aerial application.* +- [ITU-T L.103] Recommendation ITU-T L.103 (2016), *Optical fibre cables for indoor applications.* +- [ITU-T L.109.1] Recommendation ITU-T L.109.1 (2022), *Type II optical/electrical hybrid cables for access points and other terminal equipment.* +- [IEC 60227-1] IEC 60227-1 (2024), *Polyvinyl chloride insulated cables of rated voltages up to and including 450/750 V – Part 1: General requirements.* +- [IEC 60228] IEC 60228:2004, *Conductors of insulated cables.* +- [IEC 60502-1] IEC 60502-1:2021, *Power cables with extruded insulation and their accessories for rated voltages from 1 kV ( $U_m = 1,2$ kV) up to 30 kV ( $U_m = 36$ kV) – Part 1: Cables for rated voltages of 1 kV ( $U_m = 1,2$ kV) and 3 kV ( $U_m = 3,6$ kV).* +- [IEC 60793-2-10] IEC 60793-2-10:2019+AMD1:2022 CSV Consolidated version, *Optical fibres – Part 2-10: Product specifications – Sectional specification for category A1 multimode fibres.* +- [IEC 60794-1-21] IEC 60794-1-21:2015+AMD1:2020 CSV Consolidated version, *Optical fibre cables – Part 1-21: Generic specification – Basic optical cable test procedures – Mechanical test methods.* +- [IEC 60794-1-22] IEC 60794-1-22:2017, *Optical fibre cables – Part 1-22: Generic specification – Basic optical cable test procedures – Environmental test methods.* +- [IEC 60794-1-23] IEC 60794-1-23:2019, *Optical fibre cables – Part 1-23: Generic specification – Basic optical cable test procedures – Cable element test methods.* +- [IEC 60794-2] IEC 60794-2:2017, *Optical fibre cables – Part 2: Indoor cables – Sectional specification.* +- [IEC 60794-3] IEC 60794-3:2022, *Optical fibre cables – Part 3: Outdoor cables – Sectional specification.* +- [IEC 61156-1] IEC 61156-1:2023, *Multicore and symmetrical pair/quad cables for digital communications – Part 1: Generic specification.* +- [IEC 61196-1-10x] IEC 61196-1-10x-series (2022), *Coaxial communication cables – Parts 1-100 to 1- 109: Electrical test methods series.* +- [IEC 61156-2-1] IEC 61156-2-1:2010, *Multicore and symmetrical pair/quad cables for digital communications – Part 2-1: Horizontal floor wiring – Blank detail specification.* + +| | | +|----------------|---------------------------------------------------------------------------------------------| +| [IEC 62807-1] | IEC 62807-1:2017, Hybrid telecommunication cables – Part 1: Generic specification . | +| [IEC TR 62222] | IEC TR 62222:2021, Fire performance of communication cables installed in buildings . | + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +For the purposes of this Recommendation, the definitions given in [ITU-T G.650.1], [ITU-T G.650.2], and [ITU-T L.102] apply. + +## 3.2 Terms defined in this Recommendation + +None. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|--------|----------------------------------| +| BBU | Baseband Unit | +| DAS | Distributed Antenna Systems | +| DBS | Distributed Base Station | +| ELFEXT | Equal Level of Far-End crosstalk | +| FEXT | Far-End Crosstalk | +| FRP | Fibre-Reinforced Plastic | +| FTTA | Fibre-To-The-Antenna | +| NEXT | Near-End Crosstalk | +| PE | Polyethylene | +| PSNEXT | Power Sum Of Near-End Crosstalk | +| PVC | Polyvinyl Chloride | +| RRH | Remote Radio Head | +| RRU | Remote Radio Unit | + +# 5 Conventions + +None. + +# 6 Optical/metallic hybrid cable construction + +This Recommendation deals with three types of optical/metallic hybrid cables as shown in Table 1. + +**Table 1 – Contents of each cable type** + +| Cable type | Optical fibres | Metallic wires for telecommunication | Metallic wires for power feeding | +|------------|----------------|--------------------------------------|----------------------------------| +| Type I | Contained | Contained | Not contained | +| Type II | Contained | Not contained | Contained | +| Type III | Contained | Contained | Contained | + +Type I can be used for optical transmission and electric transmission carrying analogue or digital signals. Type II can be used for optical transmission and power feeding. Type III can be used for optical transmission, electric transmission carrying analogue or digital signals and power feeding. + +There are several methods to contain the media in a cable. One is to strand each medium fabricated cylindrically (with or without other materials) around a central member. Second is to arrange all media in a round way (without a central member) and put a round sheath over it. Third is to insert media into slots of a slotted core as described in clause 6.2.7. Alternatively, flat or oval configurations meeting this intent may be used. + +NOTE – Individual requirements for Type II optical/metallic hybrid cable which supports a bit rate up to 1 Gb/s or beyond can be found in [ITU-T L.109.1]. + +## **6.1 Characteristics of each medium** + +#### **6.1.1 Optical fibre** + +Optical fibres described in [ITU-T G.652], [ITU-T G.653], [ITU-T G.654], [ITU-T G.655], [ITU-T G.656], [ITU-T G.657] and [IEC 60793-2-10] should be used, depending on the circumstances and technical requirements. + +Optical fibre cable elements described in [IEC 60794-2] and [IEC 60794-3] should be used, depending on the circumstances and technical requirements. + +#### **6.1.2 Metallic wires for telecommunication** + +##### **6.1.2.1 Symmetrical metallic pair** + +The electrical and transmission characteristics of a symmetrical pair or pairs for communication should comply with those agreed between the manufacturer and the user. The following items should be agreed upon: + +- maximum conductor direct current resistance; +- maximum conductor direct current resistance unbalance of the pair; +- mutual capacitance; +- capacitance unbalance; +- attenuation (insertion loss); +- near-end crosstalk (NEXT); +- power sum of near-end crosstalk (PSNEXT); +- far-end crosstalk (FEXT); +- equal level of far-end crosstalk (ELFEXT); +- impedance; +- return loss; +- insulation resistance; +- any other parameter to be agreed between the manufacturer and the user. + +The mechanical and the environmental characteristics should comply with [IEC 61156-2-1] unless there is a different agreement between the manufacturer and the user. + +##### **6.1.2.2 Coaxial conductors** + +The electrical and transmission characteristics of coaxial conductors for communication should comply with those agreed between the manufacturer and the user. The following items should be agreed upon: + +- characteristic impedance; +- conductor resistance; +- attenuation; +- velocity ratio; +- return loss; +- insulation resistance; +- withstand voltage of dielectric; +- any other parameter to be agreed between the manufacturer and the user. + +The mechanical and the environmental characteristics should be agreed upon between the manufacturer and the user. + +#### **6.1.3 Power-feeding wires** + +The conductor characteristics of the copper wire should comply with [IEC 60228] unless there is a different agreement between the manufacturer and the user. The insulation characteristic of the copper wire should comply with [IEC 60502-1] or [IEC 60227-1] standard requirements, unless there is a different agreement between the manufacturer and the user. + +The cross-section of the metallic wire should be designed according to the transmission voltage, transmission distance and the power consumption. Under extreme operating conditions, the heat generated by the conductors should not make the cable temperature exceed the maximum allowed temperature in detailed specifications of the cable element materials. + +Conductors and insulation materials for power-feeding wires should be specified in detail. + +## **6.2 Cable element** + +The make-up of the cable core in particular the number of fibres, the method of protection and identification, the location of strength members and metallic wires or pairs, if required, should be clearly specified. Designs other than those described in clauses 6.2.1 to 6.2.16 may be used, provided that they comply with the aims of this Recommendation. + +#### **6.2.1 Tight secondary coating or buffer** + +If a tight secondary coating is required, it should consist of one or more layers of polymeric material. The coating should be easily removable for fibre splicing. For tight buffers, the buffer and fibre primary coating should be removable in one operation over a length depending on the customer's requirements. The nominal overall diameter of the tight secondary coating is typically 800/900 µm. + +In fibre-to-the-antenna (FTTA) applications, tight buffered fibres can be used. Spiral stainless steel tubes can be used to protect and gather those buffered fibres. + +#### **6.2.2 Loose tube** + +A loose tube construction or a loose tube cable is frequently used to protect and gather optical fibres or fibre ribbons. Water blocking material may be contained in the tube if required for the application. + +#### 6.2.3 Micromodule + +A micromodule is a thin-walled tubing unit. These flexible modules have bending radii similar to the unbundled fibre and are easy to strip without a tool for easy splice preparation and mid-span access. They have no shape memory and may be used directly in an enclosure up to the splicing tray. A water-blocking material may be contained in the micro-module, if required. See Figure 1. + +![Cross-sectional diagram of a micromodule showing thin and low modules wall tubing, fibre, and filling compound or dry filling solution.](e3b8510f6a2194e250205ab7bc38076d_img.jpg) + +A cross-sectional diagram of a micromodule. It consists of an outer blue ring representing the 'Thin and low modules wall tubing'. Inside this ring, there are ten green circles representing 'Fibre' units arranged in a circular pattern. The space between the fibres is filled with a 'Filling compound or dry filling solution'. A label 'L.109(18)\_F01' is located at the bottom right of the diagram. + +Cross-sectional diagram of a micromodule showing thin and low modules wall tubing, fibre, and filling compound or dry filling solution. + +**Figure 1 – Example of primary coated fibres protected by micro-module** + +#### 6.2.4 Symmetrical pair unit + +A symmetrical pair unit contains stranded metallic pairs. It is fabricated cylindrically with or without additional suitable material. Its diameter is similar to that of a loose tube. When a screen is required over the symmetrical pair, it may consist of the following: + +- an aluminium tape laminated to a plastic tape; +- an aluminium tape laminated to a plastic tape and a metal-coated or plain drain copper wire which the metal tape is in contact with; +- metallic braid; +- an aluminium tape laminated to a plastic tape and a metallic braid. + +#### 6.2.5 Coaxial unit + +A coaxial unit contains a pair of coaxial inner and outer conductors or two pairs of coaxial conductors which can form a differential line pair. The coaxial unit is fabricated cylindrically with or without additional suitable materials in order to have a diameter similar to that of a loose tube. + +#### 6.2.6 Power-feeding wire unit + +A power-feeding wire unit contains power-feeding wire(s) and is fabricated cylindrically with or without suitable material. + +#### 6.2.7 Slotted core + +In order to avoid direct pressure on optical fibres from the outside of the cable, optical fibres or ribbon fibres may be located in slots. Usually, slots are provided in a helical or SZ configuration stranded around a cylindrical rod. The slotted core usually contains a strength member (metallic or non-metallic). The strength member should adhere tightly to the slotted core in order to obtain temperature stability and avoid separation when a pulling force is applied during installation. + +#### 6.2.8 Strength member + +The cable should be designed with strength member(s) suitable to meet the installation and service conditions such that the fibre is not subjected to strain levels in excess of those agreed upon between the manufacturer and the user. The strength member(s) may be either metallic or non-metallic. + +In FTTA applications, it is recommended that non-metallic strength members be used, e.g., aramid yarns, glass fibre-reinforced plastic (FRP) rods or other suitable fibre reinforced materials. For stranded core structures, FRP rods should be laid in the centre of the core. Other types of strength members can be placed in suitable positions according to the hybrid cable structure. + +#### **6.2.9 Filler (optional)** + +If necessary, fillers can be used with a similar outer diameter to the loose tubes. They can be in the form of a circular plastic rod with a smooth surface. + +#### **6.2.10 Water blocking material (optional)** + +Filling a cable with water-blocking material or wrapping the cable core with layers of water swellable material are two means of protecting fibres from water ingress. A water-blocking element (filling compound, tapes or yarns, water swelling powder, or combination of materials) may be used. Any materials used should not be harmful to personnel. The materials in the cable should be compatible with each other and, in particular, should not adversely affect the fibre characteristics. These materials should not hinder splicing or connection operations. + +#### **6.2.11 Ripcord (optional)** + +A ripcord can be used. It should be non-hygroscopic, non-oil absorbing and have enough strength to strip the cable sheath. + +#### **6.2.12 Inner sheath (optional)** + +If required, an inner sheath over the cable core and beneath the outer sheath with an optional armouring layer and shielding layer can be used. In indoor and indoor-outdoor applications, the material of the inner sheath can be fire retardant for fire safety reasons depending on the local regulations. + +#### **6.2.13 Screen of the cable core (optional)** + +When electromagnetic compatibility or lightning proofing is required, a screen can be added over the cable core. In FTTA applications, the screen is able to reduce the current level induced by lightning and minimize the electromagnetic noise induced by the current. The screen may consist of a single or double metal tape layers (or foil), single or double metal braid layers or a combined structure of metal braid and metal tape (or foil). A drain wire in contact with the metal shield layers can be used. A metallic sheath or continuous metal armouring layer can also act as the screen of the cable core. + +#### **6.2.14 Armouring layer (optional)** + +In particular, in applications where better mechanical performance is required, an armouring layer can be added over the cable core or directly over the optical fibre unit. Armouring material can be metallic or non-metallic. + +#### **6.2.15 Outer sheath** + +The cable core should be covered with a sheath or sheaths suitable for the environmental and mechanical conditions associated with storage, installation and operation. The sheath may be of a composite construction and may include strength members. + +Sheath considerations for optical fibre cables are generally the same as for metallic conductor cables. Consideration should also be given to the amount of hydrogen generated from a metallic moisture barrier. The minimum acceptable thickness of the sheath should be stated, together with any maximum and minimum allowable overall cable diameter. + +Selection of sheath material is one of the important issues to be considered in order, for example, to ensure stability under the environmental conditions of installation and to satisfy fire safety requirements. Polyethylene (PE), polyvinyl chloride (PVC) and thermoplastic polyurethane are + +typically used as cable sheath materials for outdoor cables. Fire-retardant sheath materials may vary for indoor or indoor-outdoor cables for fire safety reasons depending on the local regulations. + +The electrical tracking resistance of sheath materials may be an issue for Type II and Type III cables. In FTTA and other outdoor applications, the outer sheath of the hybrid cable should be able to resist ultraviolet rays and heat shock. Ultraviolet shielding is commonly provided by a UV-stabilized weather resistant material containing a minimum of 2.0% by mass of well-dispersed carbon black. + +#### **6.2.16 Cable and cable elements marking** + +Hybrid cable and cable units containing optical fibres and power-feeding units should be clearly coded in order to indicate that dangerous current flows through them and distinguish one type of unit from another. + +## **6.3 Mechanical characteristics** + +Unless there is a different agreement between the manufacturer and the user, an optical/metallic hybrid cable should have the mechanical characteristics specified in [ITU-T L.100], [ITU-T L.101], [ITU-T L.102] or [ITU-T L.103] and [IEC 62807-1] depending on the installation environment. + +## **6.4 Environmental conditions** + +Unless there is a different agreement between the manufacturer and the user, an optical/metallic hybrid cable should meet the environmental conditions specified in [ITU-T L.100], [ITU-T L.101], [ITU-T L.102] or [ITU-T L.103] and [IEC 62807-1] depending on the installation environment. + +## **6.5 Fire safety** + +Requirements for fire performance in different applications may differ in each country. Optical/metallic hybrid cables should meet fire safety regulations in each country or in accordance with each telecommunication carrier. [IEC TR 62222] should be considered if there are no fire safety specifications provided. + +## **6.6 Electrical characteristics and electromagnetic compatibility** + +If required, electrical characteristics and electromagnetic compatibility requirements should be agreed between the manufacturer and user, depending on different applications, including transfer impedance and coupling attenuation of screens of metallic units and the overall screen of cable. The lightning and electrical continuity characteristics should be referred to [ITU-T L.100]. + +# **7 Test methods** + +Unless there is a different agreement between the manufacturer and user, an optical/metallic hybrid cable should be evaluated by the test methods specified in [ITU-T L.100], [ITU-T L.101], [ITU-T L.102] or [ITU-T L.103] and [IEC 62807-1] depending on the installation environment. + +## **7.1 Mechanical test methods** + +Mechanical tests should comply with [IEC 60794-1-21]. + +## **7.2 Environmental test methods** + +Environmental tests should comply with [IEC 60794-1-22]. + +## **7.3 Cable element test methods** + +Cable element test methods should comply with [IEC 60794-1-23]. + +## **7.4 Electrical characteristic test methods** + +Electrical characteristics should include voltage test, insulation resistance, conductor resistance of power-feeding wires and electrical characteristics of symmetrical metallic pairs listed in clause 6.1.2. Test methods of voltage test, insulation resistance and conductor resistance of power-feeding wires should comply with [IEC 60502-1] or [IEC 60227-1]. Test methods for electrical characteristics of symmetrical pairs should comply with [IEC 61156-1]. Test methods for electrical characteristics of coaxial units should comply with documents in the series [IEC 61196-1-10x]. + +## **7.5 Transmission characteristic test methods** + +Test methods for transmission characteristics of symmetrical pairs listed in clause 6.1.2 should comply with [IEC 61156-1]. Test methods for transmission characteristics of coaxial units should comply with documents in the series [IEC 61196-1-10x]. + +## **7.6 Electromagnetic compatibility** + +Test methods for transfer impedance and coupling attenuation should comply with [IEC 61156-1]. + +# Appendix I + +## Chinese experience + +(This appendix does not form an integral part of this Recommendation.) + +## I.1 Introduction + +Optical and metal hybrid cables are developing quickly in the access network. The cable is used not only for optical signals, but also for digital signals to be transmitted and for the power needed to feed active equipment. Wireless remote radio technology is becoming one of the most important technologies in fibre to the home (FTTH). A wireless remote radio system always contains a baseband unit (BBU) and a remote radio unit (RRU). Hybrid cables containing both optical and copper units have been adopted to connect BBU and RRU for several years, since they can transmit optical signals and power simultaneously with such advantages as low cost and easy installation. + +### I.2 Cable structure + +This Appendix presents three main types of optical fibre/stranded copper hybrid cables used in different access network application environments. Each type has been successfully installed in the access network in the People's Republic of China (PRC). + +Three main optical/metallic hybrid cables are shown in Figure I.1 to Figure I.3. + +![Cross-section diagram of a Type III hybrid cable showing its internal structure.](57b6be8f71ad3ed20e986bff929f479d_img.jpg) + +The diagram illustrates the cross-section of a Type III hybrid cable. It features a central core with a 'Central strength member' surrounded by 'Wrapping'. The cable is composed of several units: a 'Power unit' (solid black circle), an 'Optical fibre unit' (cluster of small circles), and 'Symmetrical pair' units (two concentric circles). These units are arranged around a 'Filler' material. The entire assembly is enclosed by an 'Aluminium tape' layer and an 'Outer sheath (if needed)'. Other labels include 'Stripping' and 'Jacket'. + +Cross-section diagram of a Type III hybrid cable showing its internal structure. + +**Figure I.1 – The typical optical/metallic hybrid cable structure (Type III hybrid cable)** + +This hybrid cable type is: + +- optical fibre/symmetrical pair units for optical/data signal transmission; +- optical fibre/stranded copper wire units for optical signal transmission and power feeding to the active equipment; +- optical fibre/symmetrical pair/stranded copper wire hybrid cable for optical/data signal transmission and power feeding to the active equipment. + +The transmission distance of the optical fibre/stranded copper hybrid cables mentioned in the previous clause should meet customer needs; normally the distance covered is from 100 m to 3 000 m. + +![Cross-section diagram of a hybrid optical cable with a tight-buffer optical unit and a power unit. The diagram shows a central strength member surrounded by a power unit and an optical unit. The optical unit consists of a fibre, tight buffer, aramid yarn, and jacket. The power unit consists of a power unit, jacket, and aramid yarn. The entire assembly is surrounded by an outer sheath and a shield layer.](ac852a162572ca8a8c8478c49b571af5_img.jpg) + +Labels in the diagram: Power unit, Jacket of power unit, Central strength member, Outer sheath, Aramid yarn, Fibre, Tight buffer, Aramid yarn, Jacket of optical, Wrapping, Shield layer. Reference code: L.109(18)\_FI.2 + +Cross-section diagram of a hybrid optical cable with a tight-buffer optical unit and a power unit. The diagram shows a central strength member surrounded by a power unit and an optical unit. The optical unit consists of a fibre, tight buffer, aramid yarn, and jacket. The power unit consists of a power unit, jacket, and aramid yarn. The entire assembly is surrounded by an outer sheath and a shield layer. + +**Figure I.2 – Example of a hybrid optical cable with a tight-buffer optical unit and a power unit** + +This hybrid cable type is: + +- optical fibre/stranded copper wire units for optical signal transmission and power feeding to the active equipment; +- optical fibre buffered by a tight material to be easily connected or terminated conveniently. + +![Cross-section diagram of a hybrid optical cable with a wireless remote radio unit. The diagram shows four sub-units arranged in a row within an outer sheath. Each sub-unit contains a copper unit and optical fibres. Labels include: Copper unit, Optical fibre, Sub-unit, Jacket of sub-unit, and Outer sheath. Reference code: L.109(18)_FI.3](41245ac07db266bea228735b9e8c8b73_img.jpg) + +Labels in the diagram: Copper unit, Optical fibre, Sub-unit, Jacket of sub-unit, Outer sheath. Reference code: L.109(18)\_FI.3 + +Cross-section diagram of a hybrid optical cable with a wireless remote radio unit. The diagram shows four sub-units arranged in a row within an outer sheath. Each sub-unit contains a copper unit and optical fibres. Labels include: Copper unit, Optical fibre, Sub-unit, Jacket of sub-unit, and Outer sheath. Reference code: L.109(18)\_FI.3 + +**Figure I.3 – Example of a hybrid optical cable with a wireless remote radio unit** + +This hybrid cable type is: + +- four sub-units composed of two single core optical fibre indoor cables and two copper wires; +- usually used for optical signal transmission and power feeding to the active equipment in a wireless remote system. + +### **I.3 Requirements** + +#### **I.3.1 Optical fibre** + +The optical fibres should comply with [b-ITU-T G.651.1], [ITU-T G.652] and [ITU-T G.657] requirements. The number of optical fibres ranges from two to 24 cores or according to the customer need. + +#### **I.3.2 Symmetrical pair** + +The symmetrical pair has 100 Ω resistance. The mechanical and environmental characteristics comply with those specified in [IEC 61156-2-1] and the electrical characteristics are shown in Tables I.1 to I.7. Symmetrical pair identification is shown in Table I.8. + +**Table I.1 – Electrical characteristics of 100 $\Omega$ symmetrical pair (20° C)** + +| Item | Unit | Normative diameter of the conductor | | +|--------------------------------------------------------------------|-----------------------|-------------------------------------|--------| +| | | 0.5 mm | 0.6 mm | +| Conductor direct current resistance, maximum | $\Omega/100\text{ m}$ | 9.5 | 6.58 | +| Conductor direct current resistance unbalance of the pair, maximum | % | 2.5 | | +| Working capacitance, maximum | 5, 5e | nF/100 m | 5.6 | + +**Table I.2 – Attenuation of 100 $\Omega$ symmetrical pair (20° C)** + +| Symmetrical pair type | Conductor diameter (mm) | Frequency $f$ (MHz) | Attenuation (dB/100 m) | +|-----------------------|-------------------------|---------------------|-------------------------------------------------------------------| +| 5, 5e | 0.5 | 1-100 | $1.967 \times \sqrt{f} + 0.023 \times f + \frac{0.050}{\sqrt{f}}$ | +| 5, 5e | 0.6 | 1-100 | $1.695 \times \sqrt{f} + 0.020 \times f + \frac{0.040}{\sqrt{f}}$ | + +**Table I.3 – Near-end crosstalk (NEXT) of 100 $\Omega$ symmetrical pair** + +| Symmetrical pair type | Frequency $f$ (MHz) | NEXT (dB/100 m) | +|-----------------------|---------------------|--------------------------| +| 5 | 1-100 | $62.3 - 15 \times \lg f$ | +| 5e | 1-100 | $65.3 - 15 \times \lg f$ | + +**Table I.4 – Power sum of near-end crosstalk (PSNEXT) of 100 $\Omega$ symmetrical pair** + +| Symmetrical pair type | Symmetrical pair unit | Frequency $f$ (MHz) | PSNEXT (dB/100 m) | +|-----------------------|-----------------------|---------------------|--------------------------| +| 5 | Over 4 | 1-100 | $62.3 - 15 \times \lg f$ | +| 5e | 4 | 1-100 | $62.3 - 15 \times \lg f$ | + +**Table I.5 – Characteristic impedance of 100 $\Omega$ symmetrical pair** + +| Frequency (MHz) | Characteristic impedance ( $\Omega$ ) | | +|-----------------|---------------------------------------|--------------| +| | 5 | 5e | +| $f \geq 1$ | $100 \pm 15$ | $100 \pm 15$ | + +**Table I.6 – Minimum return loss (RL) of 100 $\Omega$ symmetrical pair** + +| Type | Frequency $f$ (MHz) | | | | | +|------|---------------------|------------------|------------------|---------------------------|--------------------| +| | $1 \leq f \leq 10$ | $10 < f \leq 16$ | $16 < f \leq 20$ | $20 < f \leq 100$ | $100 < f \leq 250$ | +| 5 | $17+3 \times \lg f$ | 20 | 20 | $20 - 7 \times \lg(f/20)$ | – | +| 5e | $20+5 \times \lg f$ | 25 | 25 | $25 - 7 \times \lg(f/20)$ | – | + +**Table I.7 – Minimum structure return loss (SRL) of 100 $\Omega$ symmetrical pair** + +| Type | Frequency $f$ (MHz) | | | | | +|------|---------------------|------------------|------------------|----------------------------|--------------------| +| | $1 \leq f \leq 10$ | $10 < f \leq 16$ | $16 < f \leq 20$ | $20 < f \leq 100$ | $100 < f \leq 250$ | +| 5 | 23 | 23 | 23 | $23 - 10 \times \lg(f/20)$ | – | +| 5e | 28 | 28 | 28 | $28 - 10 \times \lg(f/20)$ | – | + +**Table I.8 – Pair identification** + +| | | +|--------|--------------| +| Pair 1 | Blue/white | +| Pair 2 | Orange/white | +| Pair 3 | Green/white | +| Pair 4 | Brown/white | + +#### I.3.3 Power unit + +The cross-section of a feeder conductor should be designed reasonably on the supply voltage, transmission distance and the power of the remote device. The inside temperature of the cable should significantly not increase during normal operating conditions. + +The feeder conductor should use a soft single conductor non-sheathed cable. If needed, hard single conductor non-sheathed cable can be used. Its performance should comply with the relevant product standards. + +The single conductor is usually an entire body within the cable length. It allows up to two joints in the cable length. The joint is connected by hot or cold welding. The tensile strength of the joint should not be less than 85% of the non-joint single entire body. Appropriate methods and materials should be adopted to repair joint insulation to meet the standard requirements for electrical performance. + +# Appendix II + +## Chinese experience on hybrid cable for mobile communications in an access network + +(This appendix does not form an integral part of this Recommendation.) + +### II.1 Introduction + +An integrated solution for a distributed base station via direct current (DC) remote power supply is proposed in this Appendix. Furthermore, the determination of the conductor cross-sectional area in the hybrid cable as well as the hybrid cable sample used in this case is also presented. + +### II.2 Background to the distributed base station + +With the development of mobile communication technology, distributed base stations (DBSs) are widely used in the 3G/4G mobile communication network in China (PRC). + +#### II.2.1 Traditional centralized base station + +The traditional centralized base station locates the BBU and radio unit in a cabinet. This base station has the advantage of a large capacity, but also the disadvantages of inconvenience in network expansion, deployment and construction, as well as high cost and large loss. The specific structures can be divided into indoor and outdoor centralized base stations, which are illustrated in Figure II.1 and Figure II.2, respectively. + +![Diagram of an indoor centralized base station setup.](27f76d622d558d3895b67244855902b7_img.jpg) + +A 3D perspective diagram showing a network infrastructure setup. On the left is a building with a grid of windows. A line connects it to a central point on a road. At this point is a small rectangular cabinet, which is highlighted by a circular callout showing a detailed view of the base station equipment inside. To the right of the cabinet is another building, also with a grid of windows. A line connects the central cabinet to this second building. The road between the buildings has several stylized trees and human figures (represented by blue icons) walking along it. The text 'L.109(18)\_FII.1' is visible in the bottom right corner of the diagram area. + +Diagram of an indoor centralized base station setup. + +Figure II.1 – Indoor centralized base station + +![Illustration of an outdoor centralized base station. A tall lattice tower with antennas is connected by a thick black cable to a large, two-tiered base station cabinet. The scene includes stylized human figures, trees, a house, and mountains in the background. Two birds are flying in the sky. The label 'L.109(18)_FII.2' is in the bottom right corner.](793eb94053441c45bcf1e1fad773a7eb_img.jpg) + +Illustration of an outdoor centralized base station. A tall lattice tower with antennas is connected by a thick black cable to a large, two-tiered base station cabinet. The scene includes stylized human figures, trees, a house, and mountains in the background. Two birds are flying in the sky. The label 'L.109(18)\_FII.2' is in the bottom right corner. + +L.109(18)\_FII.2 + +**Figure II.2 – Outdoor centralized base station** + +#### II.2.2 First generation distributed base station + +With the breakthrough of high integrated baseband processing technology, high-speed access technology and radio frequency remote technology, miniaturization and modularization of 3G base stations can be realized. The distributed base station based on radio frequency remote technology keeps the baseband part and RF part apart. The RRU is located near the antenna to handle wireless signals within base station coverage. The RRU processes and transfers the optical signal to the BBU via the optical fibres. The advantages of a separate modular design for the distributed base station include low cost, small size, deployment flexibility and convenience for network expansion, which is suitable for dense urban areas. A distributed base station is shown schematically in Figure II.3. + +![Schematic diagram of a first generation distributed base station. A blue box labeled 'BBU (Baseband unit)' is connected to another blue box labeled 'RRU (Radio remote unit)' by a double-headed arrow labeled 'Optical cable'. The entire assembly is enclosed in a dashed green rectangle labeled 'New DBS' in red text at the top. The label 'L.109(18)_FII.3' is in the bottom right corner.](a24e89a6fe9bb70c83f8bf5202baba95_img.jpg) + +Schematic diagram of a first generation distributed base station. A blue box labeled 'BBU (Baseband unit)' is connected to another blue box labeled 'RRU (Radio remote unit)' by a double-headed arrow labeled 'Optical cable'. The entire assembly is enclosed in a dashed green rectangle labeled 'New DBS' in red text at the top. The label 'L.109(18)\_FII.3' is in the bottom right corner. + +**Figure II.3 – First generation distributed base station** + +#### II.2.3 Second generation distributed base station + +The separate design for the BBU and RRU has many advantages, but also brings new challenges to the power supply for the RRU. + +There are three solutions for RRU power supply for a distributed base station: DC remote power supply, independent AC power supply and independent power supply via solar energy. In this Appendix, an integrated solution based on a DC remote power supply, which is called a second generation distributed base station with a centralized power supply, is proposed and presented. + +The second generation distributed base station is suitable for communication network coverage area with a guard-free base station and room-free base station in order to reduce costs during operation and maintenance, as shown in Figure II.4. + +![Diagram of a second generation distributed base station. It shows a BBU (Baseband Unit) on the left connected by a dashed line to an RRU (Remote Radio Unit) on the right, which is mounted on a vertical pole with an antenna. The label 'L.109(18)_FII.4' is at the bottom right.](e69b9188aa2c14ec6b21c83f711fef65_img.jpg) + +Diagram of a second generation distributed base station. It shows a BBU (Baseband Unit) on the left connected by a dashed line to an RRU (Remote Radio Unit) on the right, which is mounted on a vertical pole with an antenna. The label 'L.109(18)\_FII.4' is at the bottom right. + +**Figure II.4 – Second generation distributed base station** + +#### II.2.4 The topology of a distributed base station + +With the large data flow in the 4G network, the frequency level of the base station increases, and the coverage radius of the base station is reduced. The network topology between the BBU and RRU for the distributed base station becomes more complicated. There are several types of network topology from BBU to RRU, such as P2P, star, chain, ring and mixture structures. + +![Diagram illustrating five network topologies for distributed base stations: a) P2P (Point-to-Point) showing one BBU connected to one RRU via an Ir interface; b) Star showing one BBU connected to multiple RRUs via Ir interfaces; c) Chain showing one BBU connected to a series of three RRUs via Ir interfaces, with the RRUs connected to antennas; d) Ring showing one BBU connected to two RRUs in a ring configuration via Ir interfaces; e) Mixed showing one BBU connected to a combination of star and chain topologies via fibre optic cables. The label 'L.109(18)_FII.5' is at the bottom right.](09955ff8214ffb6947951fc0f60eb6ab_img.jpg) + +Diagram illustrating five network topologies for distributed base stations: a) P2P (Point-to-Point) showing one BBU connected to one RRU via an Ir interface; b) Star showing one BBU connected to multiple RRUs via Ir interfaces; c) Chain showing one BBU connected to a series of three RRUs via Ir interfaces, with the RRUs connected to antennas; d) Ring showing one BBU connected to two RRUs in a ring configuration via Ir interfaces; e) Mixed showing one BBU connected to a combination of star and chain topologies via fibre optic cables. The label 'L.109(18)\_FII.5' is at the bottom right. + +**Figure II.5 – P2P, star, chain, ring, and mixture structures** + +### II.3 The integrated solution of distributed base station via DC centralized remote power supply + +#### II.3.1 DC remote power supply solution for DBS + +The original "RRU DC remote power supply solution" has the advantages such as a simple structure and high reliability. However, because the DC power supply voltage is low, the transmitted current value is relatively large, which results in high costs due to the large size of power conductors. At the same time, the longer the transmission distance, larger the voltage drop and the power loss will occur. Therefore, this contribution provides a smart integrated solution which includes a DC booster located near the BBU to boost DC -48 V to 380 V or 350 V. Then the power module located near the RRU + +transforms 380 V or 350 V into –48 V for the power supply for RRU. The hybrid cable is used to connect the BBU with the RRU directly. + +#### II.3.2 DC remote power supply unit of a distributed base station + +The integrated solution of a DC remote power supply for DBS is shown schematically in Figure II.6. + +![Figure II.6 – DC remote supply unit diagram of a distributed base station. The diagram shows a BBU (DC booster, Remote supply power CO, DC-48V power supply) connected to an RRU (Remote power module) via a Hybrid cable. The entire system is enclosed in a dashed green box labeled 'DC remote supply DBS'.](eb03559a4d92ea9ebd63ea9be663c50a_img.jpg) + +The diagram illustrates the DC remote supply unit for a distributed base station. It consists of two main components: a BBU (Base Station Unit) on the left and an RRU (Remote Radio Unit) on the right, connected by a 'Hybrid cable'. The BBU is labeled with 'DC booster (Remote supply power CO)' and 'DC-48V power supply'. The RRU is labeled 'Remote power module'. Both components are enclosed within a dashed green rectangular boundary. Above the BBU, the text 'DC remote supply DBS' is written in red. In the bottom right corner of the diagram, the identifier 'L.109(18)\_FII.6' is present. + +Figure II.6 – DC remote supply unit diagram of a distributed base station. The diagram shows a BBU (DC booster, Remote supply power CO, DC-48V power supply) connected to an RRU (Remote power module) via a Hybrid cable. The entire system is enclosed in a dashed green box labeled 'DC remote supply DBS'. + +Figure II.6 – DC remote supply unit diagram of a distributed base station + +#### II.3.3 Direct current remote power supply circuit diagram + +The principle for DC remote power supply solution can be simplified as a circuit diagram as shown in Figure II.7, and the voltage drop on the conductor in the hybrid cable can be calculated as shown in equation (1), while the ring resistance of the conductor in hybrid cable can be calculated as shown in equation (2). + +$$\Delta U = U_i - U_o = 2 \times L \times R_c = 2P \times R_c / U_o \quad (1)$$ + +$$R = R_c + R_c = 2 \times R_c = 2 \times (\rho \times \lambda_1 \times \lambda_2 \times l / A) \quad (2)$$ + +$$L = \lambda_3 U_i^2 / (4P \times R) \quad (3)$$ + +Where, + +$R$ denotes ring resistance + +$U_i$ denotes input voltage after the DC booster + +$U_o$ denotes output voltage for RRU + +$L$ denotes remote distance of DBS + +$R_c$ denotes resistance of the conductor + +$\Delta U$ denotes voltage drop on the conductor + +$\rho$ denotes resistivity ( $\Omega \cdot \text{mm}^2/\text{m}$ ) + +$l$ denotes conductor length (m) + +$A$ denotes nominal area of the conductor ( $\text{mm}^2$ ) + +$P$ denotes rated power of RRU (W) + +$\lambda_1$ denotes stranding ratio, usually 1.0133 + +$\lambda_2$ denotes safety margin, usually 1.03-1.15 + +$\lambda_3$ denotes transfer efficiency for remote equipment power, usually 0.80-0.90 + +![Figure II.7 – Direct current remote power supply circuit diagram. The diagram shows a closed loop circuit. On the left is a DC voltage source labeled U_i. On the right is a Remote Radio Unit (RRU) labeled U_o. The top wire contains a resistor labeled R_c, and the bottom wire contains another resistor labeled R_c. Arrows indicate current flow: from U_i through the top R_c to the RRU, and from the RRU through the bottom R_c back to U_i. Above the top resistor, the voltage difference is labeled ΔU = U_i - U_o. The diagram is labeled L.109(18)_FII.7 at the bottom right.](c5452f95f3b28f1bfe29e84fbc2e1267_img.jpg) + +``` + +graph LR + Source((U_i)) -- R_c_top --> RRU[RRU U_o] + RRU -- R_c_bottom --> Source + subgraph " " + R_c_top[R_c] + R_c_bottom[R_c] + end + style Source fill:none + style RRU fill:none + +``` + +Figure II.7 – Direct current remote power supply circuit diagram. The diagram shows a closed loop circuit. On the left is a DC voltage source labeled U\_i. On the right is a Remote Radio Unit (RRU) labeled U\_o. The top wire contains a resistor labeled R\_c, and the bottom wire contains another resistor labeled R\_c. Arrows indicate current flow: from U\_i through the top R\_c to the RRU, and from the RRU through the bottom R\_c back to U\_i. Above the top resistor, the voltage difference is labeled ΔU = U\_i - U\_o. The diagram is labeled L.109(18)\_FII.7 at the bottom right. + +**Figure II.7 – Direct current remote power supply circuit diagram** + +#### II.3.4 Copper conductor design + +Based on equation (2) and the resistivity of a copper conductor, the resistance parameters can be calculated as shown in Table II.1. + +**Table II.1 – Relevant resistance parameters for a copper conductor** + +| Conductor cross-sectional area (mm 2 ) | Length of cable (m) | Resistance of conductor $R_c$ (Ω) | Ring resistance $R$ (Ω) | +|---------------------------------------------------|---------------------|-----------------------------------|-------------------------| +| 1.5 | 1 000 | 13.3 | 26.6 | +| 2.5 | 1 000 | 7.98 | 15.96 | +| 4.0 | 1 000 | 4.95 | 9.90 | +| 6.0 | 1 000 | 3.30 | 6.60 | + +The resistivity of a copper conductor is 0.01757. + +Based on equations (1), (2) and (3), the relationship matrix regarding remote distance, DC remote supply voltage, copper conductor cross-sectional area and rated RRU power can be obtained as shown in Table II.2. + +**Table II.2 – Relationship matrix regarding remote distance, DC voltage, conductor cross-sectional area and rated remote radio unit power** + +| Total power for the remote radio unit (W) | Remote distance (km) | | | | | | | | +|-------------------------------------------|-----------------------------------|---------|---------|---------|-----------------------------------|---------|---------|---------| +| | 350 VDC | | | | 380 VDC | | | | +| | Nominal area for copper conductor | | | | Nominal area for copper conductor | | | | +| | 2 × 1.5 | 2 × 2.5 | 2 × 4.0 | 2 × 6.0 | 2 × 1.5 | 2 × 2.5 | 2 × 4.0 | 2 × 6.0 | +| 200 | 4.2 | 6.9 | 11.5 m | 16.8 | 5.6 | 9.2 | 14.8 | 22.4 | +| 300 | 2.8 | 4.7 | 7.7 | 11.2 | 3.7 | 6.0 | 9.7 | 14.8 | +| 400 | 2.1 | 3.5 | 5.7 | 8.4 | 2.8 | 4.6 | 7.4 | 11.2 | +| 600 | 1.4 | 2.4 | 3.4 | 5.6 | 1.9 | 3.0 | 4.9 | 7.6 | +| 800 | 1.1 | 1.8 | 2.9 | 4.2 | 1.4 | 2.3 | 3.7 | 5.6 | +| 1 000 | 0.90 | 1.4 | 2.3 | 3.6 | 1.1 | 1.8 | 3.0 | 4.4 | +| 1 200 | 0.70 | 1.2 | 1.7 | 2.8 | 1.0 | 1.5 | 2.5 | 4.0 | + +#### II.3.5 Aluminium conductor design + +Based on equation (2) and the resistivity of an aluminium conductor, the resistance parameters can be calculated as shown in Table II.3. + +**Table II.3 – Relevant resistance parameters for an aluminium conductor** + +| Conductor cross-sectional area (mm 2 ) | Length of cable (m) | Resistance of conductor $R_c$ (Ω) | Ring resistance $R$ (Ω) | +|---------------------------------------------------|---------------------|-----------------------------------|-------------------------| +| 6.0 | 1 000 | 4.61 | 9.22 | +| 8.0 | 1 000 | 3.83 | 7.66 | +| 10.0 | 1 000 | 3.08 | 6.16 | +| 16.0 | 1 000 | 1.91 | 3.82 | + +The resistivity of an aluminium conductor is 0.02838. + +Based on equations (1), (2) and (3), the relationship matrix regarding remote distance, DC remote supply voltage, aluminium conductor cross-sectional area and rated RRU power can be obtained as shown in Table II.4. + +**Table II.4 – Relationship matrix regarding remote distance, DC voltage, conductor cross-sectional area and rated remote radio unit power** + +| Total power for remote radio unit (W) | Remote distance (km) | | | | | | | | +|---------------------------------------|--------------------------------------|---------|----------|----------|--------------------------------------|---------|----------|----------| +| | 350 VDC | | | | 380 VDC | | | | +| | Nominal area for aluminium conductor | | | | Nominal area for aluminium conductor | | | | +| | 2 × 6.0 | 2 × 8.0 | 2 × 10.0 | 2 × 16.0 | 2 × 6.0 | 2 × 8.0 | 2 × 10.0 | 2 × 16.0 | +| 200 | 5.8 | 7.6 | 9.6 | 15.2 | 7.7 | 10.2 | 12.8 | 15.4 | +| 300 | 3.8 | 5.2 | 6.4 | 10.4 | 5.1 | 7.0 | 8.6 | 14.0 | +| 400 | 2.9 | 3.8 | 4.8 | 7.6 | 3.9 | 5.2 | 6.4 | 10.4 | +| 600 | 1.9 | 2.6 | 3.2 | 5.2 | 2.6 | 3.6 | 4.3 | 7.2 | +| 800 | 1.5 | 2.0 | 2.4 | 4.0 | 2.0 | 2.6 | 3.2 | 5.2 | +| 1 000 | 1.2 | 1.6 | 1.9 | 3.2 | 1.5 | 2.0 | 2.6 | 4.0 | +| 1 200 | 1.0 m | 1.4 | 1.6 | 2.8 | 1.3 | 1.8 | 2.2 | 3.6 | + +#### II.3.6 Hybrid optical and electrical cable design + +##### II.3.6.1 Design principles + +The hybrid optical and electrical cable described here is a kind of cable via a centralized DC power supply. The cable design includes conductor cross-sectional area, as illustrated in clauses II.3.4 and II.3.5 and fibre core design, which is affected by the topology between the BBU and the RRU. + +For an outdoor distributed base station, a star type topology is generally adopted. The antenna of a base station for mobile communication usually has three sectors. Each of them connects an RRU independently. Every connection between the BBU and RRU usually occupies two single-mode optical fibre channels. Thus, six fibres are required for a base station. Considering fibre backup, 12 fibres are sufficient for a base station. In some cases, such as towers with two base stations or when a future upgrade is predicted, the design of a hybrid optical and electrical cable with 24 fibres is required. + +##### II.3.6.2 Design example + +A kind of hybrid optical and electrical cable is designed as shown in Figure II.8. Single mode fibres (SMFs) are contained in the loose tube filled with jelly. A steel wire is employed as the central strength member. Tubes and insulated copper conductors are stranded around the central strength + +member. An aluminium polyethylene laminate (APL) tape is longitudinally wrapped around the cable core. Then, the cable core is extruded with a PE sheath. + +![Cross-section diagram of a hybrid cable showing its internal structure.](f2f0092624aaf8ad2bcb99a821409714_img.jpg) + +The diagram illustrates the cross-section of a hybrid cable. It features a central grey circular core labeled 'CSM'. Surrounding this are two 'Copper conductor wire' units, each consisting of a bundle of wires surrounded by a red insulation layer. Interspersed between the copper wires are two 'Optical fibre unit' assemblies, each containing multiple optical fibers surrounded by a blue insulation layer. The entire assembly is embedded in 'Flooding compound'. A layer of 'APL tape' (represented by a blue ring) is wrapped around the core, and the entire cable is covered by an 'Outer sheath' (the thick black outer layer). A 'Ripcord' is indicated by a small white dot on the left side of the outer sheath. The label 'L.109(18)\_FII.8' is positioned below the diagram. + +Cross-section diagram of a hybrid cable showing its internal structure. + +**Figure II.8 – Hybrid cable cross-section for GDTA –24B1.3+2\*4 mm2** +CSM: central strength member + +The hybrid cable design has the following advantages: + +- small size, light weight, easy installation and low cost; +- combines optical fibre cable with power cable; +- good mechanical properties and electrical properties, as well as environmental performance; +- the cable design of "two copper wires and 24 optical fibres" is suitable for the flexible topology between the BBU and the RRU. + +### II.4 Conclusion + +This appendix introduces an integrated solution for a distributed base station via DC remote power supply, including the design of a conductor cross-sectional area in a hybrid cable, as well as the design of an optical cable core. The relationship matrix regarding remote distance, DC remote supply voltage, conductor cross-sectional area and rated RRU power is also given. It can ensure smart mobile communication by offering a stable power supply to the base station. + +# Appendix III + +## French/Polish experience + +(This appendix does not form an integral part of this Recommendation.) + +### III.1 Introduction + +The hybrid cable design in this appendix is an example of a typical cable construction that is used for a fixed access network (FAN) and a radio access network (RAN), e.g., for remote radio head (RRH) installations. In the hybrid cable, optical fibres provide data communication and copper conductors provide 400 VDC remote powering solutions. See Figure III.1. + +![Diagram illustrating the installation of a remote radio head (RRH) using a hybrid cable. A central office (400 VDC central office and remote powering [ETSI EN 302 099]) is connected via a hybrid cable to a radio access network (RAN) and a fixed access network (FAN). The hybrid cable contains optical fibres (Fibre) and energy conductors (Energy conductor). The RAN is connected to a base station (RRH) on a tower, and the FAN is connected to a base station on a building. A call icon is shown near the central office.](4cde160bcc69b7b6c81b648dd0e4252e_img.jpg) + +The diagram shows a central office unit labeled "400 VDC central office and remote powering [ETSI EN 302 099]". A "Hybrid cable" connects this unit to two networks: "FAN" (Fixed Access Network) and "RAN" (Radio Access Network). The hybrid cable is shown in cross-section, with "Fibre" (optical fibres) and "Energy conductor" (copper conductors) inside. The FAN side connects to several streetlights. The RAN side connects to a tall radio tower and a building. A circular inset on the right shows a close-up of the hybrid cable connector. The label "L.109(18)\_FIII.1" is in the bottom right corner. + +Diagram illustrating the installation of a remote radio head (RRH) using a hybrid cable. A central office (400 VDC central office and remote powering [ETSI EN 302 099]) is connected via a hybrid cable to a radio access network (RAN) and a fixed access network (FAN). The hybrid cable contains optical fibres (Fibre) and energy conductors (Energy conductor). The RAN is connected to a base station (RRH) on a tower, and the FAN is connected to a base station on a building. A call icon is shown near the central office. + +Figure III.1 – Example for remote radio head installation + +### III.2 Cable design + +The cable is realized with one or several copper pairs of conductors with a cross-sectional area 2.5 mm2 or 4 mm2, 12 to 48 (modulo 12) single-mode fibres and rip cords. + +For example, if total copper pairs of cross-sectional area 10 mm2 are required, a cable of four 2.5 mm2 copper pairs can be used with the number of fibres needed. The required total copper cross-sectional area to feed a remote site is in the range of 2.5 mm2 to 25 mm2 for 400 VDC, depending on the power required and the distance to be covered. + +The cable can be shielded or unshielded. If screened, a drain wire is needed. + +The overall jacket is made of PVC or thermoplastic elastomer-halogen-free (TPE-HF) material. + +The cable design allows a small bend radius and excellent cable routing properties. + +The following sheath marking has been developed: + +COMPANY NAME\_DD YY WW\_MANUFACTURER\_HYBRID (ref) XXXX\_(number of fibres) +XX FO\_(fibres type) XXXX + (number of conductors) XX x (cross-section) XX mm2\_\_\_ 400VDC +\_\_\_(length)XXX + +Insulation material: The material for insulation should be PE cross-linked, halogen free with the following identification: red, black. + +The cable is easily identified with three red lines integrated on the sheath around the cable to indicate the presence of a potential high voltage in the core. See Figure III.2. + +![Cross-section diagram of a hybrid cable showing its internal structure. The diagram is circular with a black outer sheath. Inside, there's a central light blue optical unit with a small white core containing several dots. Surrounding the optical unit are several yellow circles representing power feeding wires, some with red rings. These are interspersed with grey circles representing filler. The entire assembly is surrounded by a light blue layer. Labels with leader lines point to various parts: 'Red marker' points to a red segment on the outer sheath; 'Sheath' points to the outer black layer; 'Power feeding wires' points to one of the yellow circles; 'Filler' points to one of the grey circles; 'Optical unit' points to the central light blue circle; and 'Ripcord' points to a small black dot on the inner edge of the sheath. The diagram is labeled 'L.109(18)_FIII.2' at the bottom right.](8c348bf9c2c81b018017ae1d19506a9a_img.jpg) + +Cross-section diagram of a hybrid cable showing its internal structure. The diagram is circular with a black outer sheath. Inside, there's a central light blue optical unit with a small white core containing several dots. Surrounding the optical unit are several yellow circles representing power feeding wires, some with red rings. These are interspersed with grey circles representing filler. The entire assembly is surrounded by a light blue layer. Labels with leader lines point to various parts: 'Red marker' points to a red segment on the outer sheath; 'Sheath' points to the outer black layer; 'Power feeding wires' points to one of the yellow circles; 'Filler' points to one of the grey circles; 'Optical unit' points to the central light blue circle; and 'Ripcord' points to a small black dot on the inner edge of the sheath. The diagram is labeled 'L.109(18)\_FIII.2' at the bottom right. + +**Figure III.2 – Example cross-section of the hybrid cable** + +# Appendix IV + +## Swiss experience + +(This appendix does not form an integral part of this Recommendation.) + +### IV.1 Introduction + +The hybrid cable design in this appendix is an example of a typical construction that is used for RRH installations by several network operators. In the hybrid cable, optical fibres provide optical data communication, and the copper conductors provide power feeding. + +### IV.2 Cable design + +The cable, as shown in Figure IV.1, contains 12 copper conductors of American wire gauge (AWG) 6 mm2 or 16 mm2, a compact cable with 24 single-mode fibres, a drain wire, shielding and rip cords. The overall jacket is made of PVC or TPE-HF material. + +The shielding of the hybrid cable, one layer (of thickness 0.05 mm) of 100% copper tape wrapped around the conductors and drain wire enables the use of grounding kits between the base transmission station and the RRHs. The cable design allows a small bend radius and excellent cable routing properties. + +The copper shield and the AWG 6 mm2 or 16 mm2 drain wire maintain contact throughout the cable run and ensure an appropriate earthing feature. The rip cords offer an easy and quick stripping of the cable jacket. + +![Cross-section of the hybrid cable showing 12 copper conductors, optical fibers (FO), and a drain wire.](b800561cd10527de6f3f41b23b562990_img.jpg) + +A cross-sectional diagram of a hybrid cable. The outermost layer is a thick black circular jacket. Inside this jacket, there are 12 circular copper conductors, each with a brown, textured internal core. These conductors are arranged in a circular pattern. Interspersed between the conductors are several smaller circular elements: yellow circles representing optical fibers, a grey circle labeled 'FO' (Fiber Optic), and a single small black circle representing a drain wire. The entire assembly is surrounded by a thin, dark circular layer representing the shielding. The diagram is labeled 'L.109(18)\_FIV.1' at the bottom right. + +Cross-section of the hybrid cable showing 12 copper conductors, optical fibers (FO), and a drain wire. + +Figure IV.1 – Cross-section of the hybrid cable + +### IV.3 Application + +The cable configuration in Figure IV.1 enables up to six RRH to be connected. The cable has to perform well under outdoor thermal conditions and has to meet the specified fire performance requirements. + +Such cables are used for dedicated cabling systems, which include a ruggedized enclosure and robust breakout-out cables open-ended or terminated with the connectors. The cabling systems are usually factory terminated and supplied by cabling system manufacturers. + +## **IV.4 Conclusion** + +A factory-terminated hybrid cabling system is an efficient and easy to install cabling solution. It can be installed in approximately half of the time of the competitive hybrid solutions based on the corrugated coax cable designs. + +# Bibliography + +- [b-ITU-T G.651.1] Recommendation ITU-T G.651.1 (2018), *Characteristics of a 50/125 µm multimode graded index optical fibre cable for the optical access network.* +- [b-ITU-T TR-OFCS] ITU-T Technical Report TR-OFCS (2015), *Optical fibres, cables, and systems.* +- [ETSI EN 302 099] ETSI EN 302 099 V2.1.30 (2020), *Environmental Engineering (EE); Powering of equipment in access network.* + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|----------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.11-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg b/marked/L/T-REC-L.11-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..64672153e39c851d9e16fdbc702e526c7ba7e8a7 --- /dev/null +++ b/marked/L/T-REC-L.11-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:454a9958ffe168868cb7d38a0eb24418dafe31a7a4245c992089b2316ac37d3e +size 7392 diff --git a/marked/L/T-REC-L.11-198811-I_PDF-E/5b8a756d9a71c35f17db8bcb90b438a3_img.jpg b/marked/L/T-REC-L.11-198811-I_PDF-E/5b8a756d9a71c35f17db8bcb90b438a3_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..c875f553e249ad72c888c83268cfcdf71ff26ebb --- /dev/null +++ b/marked/L/T-REC-L.11-198811-I_PDF-E/5b8a756d9a71c35f17db8bcb90b438a3_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:c929cb7a463942df4fe0bd450a2e5235df90654243e0a8fd0ac8e88cc6a184a5 +size 71610 diff --git a/marked/L/T-REC-L.11-198811-I_PDF-E/81a4cbf0b3c4cbc065efdf8f800dadde_img.jpg b/marked/L/T-REC-L.11-198811-I_PDF-E/81a4cbf0b3c4cbc065efdf8f800dadde_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..764c96b1c81804ef3d17c96b2a506d35e3d10588 --- /dev/null +++ b/marked/L/T-REC-L.11-198811-I_PDF-E/81a4cbf0b3c4cbc065efdf8f800dadde_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:c87e712e761062ed359c656e1255cda9f1ec2a5f37e2ead93d10d8251f4bdbaf +size 60492 diff --git a/marked/L/T-REC-L.11-198811-I_PDF-E/e180f2b5fcbe8001554a7c0677cd3f82_img.jpg b/marked/L/T-REC-L.11-198811-I_PDF-E/e180f2b5fcbe8001554a7c0677cd3f82_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..b8059ecb6574979b5d3fe3c2ff5ed5e1f244735b --- /dev/null +++ b/marked/L/T-REC-L.11-198811-I_PDF-E/e180f2b5fcbe8001554a7c0677cd3f82_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:b952a37662ba95279bc275ac1dd2ed65f08e23adc63a0e31ecaa496cf4182bff +size 117414 diff --git a/marked/L/T-REC-L.11-198811-I_PDF-E/raw.md b/marked/L/T-REC-L.11-198811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..b6f06feba0d097d5020699e18f05ef9301542c05 --- /dev/null +++ b/marked/L/T-REC-L.11-198811-I_PDF-E/raw.md @@ -0,0 +1,898 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features the letters 'ITU' in a bold, sans-serif font, superimposed on a stylized globe with intersecting lines. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.11** + +**CONSTRUCTION, INSTALLATION AND +PROTECTION OF CABLES AND OTHER ELEMENTS +OF OUTSIDE PLANTS** + +--- + +**JOINT USE OF TUNNELS BY PIPELINES +AND TELECOMMUNICATION CABLES, AND +THE STANDARDIZATION OF UNDERGROUND +DUCT PLANS** + +**ITU-T Recommendation L.11** + +(Extract from the *Blue Book*) + +--- + +# NOTES + +1 ITU-T Recommendation L.11 was published in Volume IX of the *Blue Book*. This file is an extract from the *Blue Book*. While the presentation and layout of the text might be slightly different from the *Blue Book* version, the contents of the file are identical to the *Blue Book* version and copyright conditions remain unchanged (see below). + +2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +# Recommendation L.11 + +# JOINT USE OF TUNNELS BY PIPELINES AND TELECOMMUNICATION CABLES, AND THE STANDARDIZATION OF UNDERGROUND DUCT PLANS + +(Melbourne, 1988) + +The CCITT, + +*considering* + +- (a) that many countries are interested in the joint use of tunnels and are aware of the advantages, disadvantages and specific dangers they hold; +- (b) that the rules governing this type of ducting vary significantly from country to country; +- (c) that the importance of the joint use of tunnels increases with increasing density of population and shrinking open spaces, i.e. in large towns; + +*recommends* + +that Administrations, who in the future will be interested in this type of installation, follow the rules described in this Recommendation. + +## 1 General considerations + +Duct tunnels and trenches are constructions containing one or generally more ducts belonging to different networks. Tunnels which can be inspected (inspectable tunnels) include one or more gangways for initial assembly work and for subsequent control, maintenance and repair operations. A tunnel without standing room, but designed for crawling should have a clear internal height of at least 0.8 m. Duct gangways may not be entered. + +The above principles apply to inspectable tunnels, and apply by analogy to tunnels with crawling room only. + +Tunnels may contain ducts belonging to the following types of networks: + +- collective antennas; +- telecommunications; +- electricity; +- gas; +- water; +- district heating; +- ducted transport (e.g. pneumatic tubes); +- drainage water. + +## 2 Establishment of a routing plan + +### 2.1 Structure + +Tunnel routing must take into account the structure of networks and their levels of priority. + +The transport ducts of different networks do not generally follow the same itinerary, since neither the production units (e.g., power plants, pumping stations or telephone exchanges) nor the transit points from transport to primary distribution coincide. On the other hand, in densely populated areas, primary and secondary distribution ducts often do follow the same itineraries, so that it is advisable to run tunnels under arteries containing primary and secondary distribution ducts. + +### 2.2 Decision criteria + +The following factors should be taken into account when opting between trenches and tunnels: + +#### 2.2.1 *Distribution security* + +A high level of distribution security will depend on the following factors: + +- durability of material and joints; +- rapid location of damage when it occurs, easy access and minimum repair times; +- low exposure to outside effects (e.g. damage caused by third parties or by earthquakes). + +Ducts laid in tunnels generally offer high durability and a low risk of deterioration. They may be repaired rapidly. + +#### 2.2.2 *Third party risk, disturbances due to installation and repair work* + +Account should be taken of disturbances caused by installation and repair work (rerouting of traffic, noise) and of the possible consequences of damages ducts (water and fire damage). + +#### 2.2.3 *Economic considerations* + +Economic considerations should include not only the cost of constructing and maintaining tunnels, but also the savings which will arise in the future from avoiding the secondary effects of buried ducts. By secondary effects are meant the effects produced on local inhabitants, local activities, vehicle traffic and the environment in general by the installation, malfunction, repair and maintenance of ducts. + +#### 2.2.4 *Technical considerations* + +Before either of the laying methods is chosen, the following factors should be considered: + +- ducts, network, dimension (cross-section), power (capacity), material, protection against corrosion, number, distribution priority, duct routing, compatibility with other ducts, state of ducts, repairs, overhaul, replacement, reserves, extensions, emergency ducts, provisional installations connections to buildings; +- roadway, road width, pavement width, greenery strip, traffic density, surface water drainage, superstructure; +- subsoil, type of ground, groundwater level, existing ducts, existing underground constructions; +- schedules, beginning of works, duration of works (stages), start-up. + +When a tunnel is planned, special attention should be paid to branch connections with buildings, which may be derived directly from the tunnel if the necessary openings have been provided. An alternative method is to bury secondary distribution ducts alongside the tunnel. + +## 3 **Recommendations applicable to tunnels** + +### 3.1 *Phases* + +The following sequence of phases should be considered: + +- construction phase; +- operational phase. + +### 3.2 *General recommendations* + +In both the construction and the operational phases, the following requirements should be observed: + +- *Introduction of duct components in the tunnel* + +It should be possible to introduce any components either through normal access points or through special openings. + +- *Cable pulling* + +Cables in tunnels should be placed in appropriate technical containers, in order to facilitate their installation, repositioning or removal. + +- *Construction aids* + +For construction work, especially in the case of heavy tubing, securing devices should be provided at appropriate locations. + +- *Movement of duct components in tunnel* + +The necessary facilities should be provided for the transport of duct components inside a tunnel. + +- *Reserve facility for network extension* + +Since networks are likely to be extended on the future, appropriate reserve space should be set aside in the tunnel cross-section plan. + +- *Clear space around ducts* + +Enough clear space should be allowed between a tunnel wall and ducts, as well as between ducts in proportion to their diameter (to facilitate maintenance, repair and branching). + +- *Ambient temperature* + +High temperatures may occur in tunnels containing heat-emitting ducts. Care should be taken to maintain physiologically acceptable environmental conditions in order to avoid any impairment to health during work or inspections. For telecommunication cables, see § 3.3.2. + +- *Corrosion of ducts, fixtures and equipment accessories* + +The working life of fixtures and equipment accessories should be as long as that of the ducts. High levels of humidity may produce condensation and cause non-rustproof metals to corrode. The appearance of corrosion should be considered in the light of Recommendation L.1. Metal components (pillars, racks or supports) should preferably be made of hot galvanized steel. In some cases, cathodic protection may be applied. + +- *Vibrations* + +Some ducts may be sensitive to vibrations. In some cases, vehicle traffic may produce vibrations which are propagated inside the tunnels. + +### 3.3 *Comments on distribution networks* + +#### 3.3.1 *Collective antennas* + +Extra space has to be provided in places to house amplifying equipment. Apart from that, collective antenna cables have no special requirements. + +#### 3.3.2 *Telecommunication cables* + +The following requirements should be taken into account: + +- *Distances from power lines* + +Minimum distances from main ducts should be applied (see § 5). + +- *Protection against thermal load* + +Since telecommunications cables are vulnerable to thermal load, thermal conditions in tunnels must be taken into account. This applies especially for optical cables. + +- *Protection against corrosion and lightning* + +Telecommunication cables should generally be protected by metal sheaths or shields. This protection may be applied, but the use of joint earth electrodes is either not required or not permissible. + +- *Protection against electrical interference* + +Normally no special measures need be taken, although cable constructions with a high screening factor or overvoltage relays may be used in some cases. + +- *Protection against mechanical forces* + +Metal shields may be used to protect cables against mechanical effects such as vibrations or impacts. In the case of lead sheaths, vibration-resistant alloys should be used. + +- *Protection against outside effects* + +Plastic-covered cables may be protected against rodents with fibreglass or aramid-fibre shielding. + +Contractable cable joints may provide protection against earthquakes. + +- *Bends* + +Since cable curvature is limited, layout plans must take account of permitted curvature radii. + +- *Specialized work* + +Since work has to be done relatively frequently on telecommunication installations, particularly on sleeves, sufficient working space should be provided (e.g. alcoves or chambers). + +#### 3.3.3 Power cables + +The following requirements should be taken into account: + +##### - *Bends* + +The same rules apply, by analogy, as for telecommunication cables. + +##### - *Ambient temperature* + +The load capacity of electrical cables depends, among other parameters, on ambient temperature, which should be determined in each case to achieve the ideal balance between tunnel cooling and cable load capacity. + +#### 3.3.4 Gas + +Tunnels containing gas ducts should be ventilated (naturally or artificially). Dilation sleeves should be leakproof and located in separate chambers. + +#### 3.3.5 Water + +The choice of tunnel layout or cross-section should take account of the dimensions of special water duct components. Water ducts may require special precautions against climatic effects to avoid overheating or freezing. Ducts with a nominal diameter of 150 mm may give rise to special problems, in which case the following factors should be taken into account: + +##### - *Temperature rise* + +A rise of temperature in a tunnel will have only a negligible effect on the quality of drinking water. + +##### - *Freezing in ducts* + +The temperature in inspectable tunnels rarely falls below freezing. Should there be a risk of freezing, appropriate measures should be taken to protect the duct. + +##### - *Bleeding and draining* + +Bleeding and draining facilities should generally be located outside tunnels. + +#### 3.3.6 District heating + +The following requirements should be taken into account: + +##### - *Position of ducts* + +For assembly purposes, the distance between district heating ducts (not including insulation) and the tunnel wall should not be less than 0.3 m. + +##### - *Heatproofing* + +Continuous thermal insulation will diminish heat losses and help prevent the occurrence of thermal shock in the event of a burst water duct. + +##### - *Junctions and intersections* + +Permitted radii of curvature for ducts should be observed at junctions and intersections. + +##### - *Dilation devices* + +Plans should allow sufficient space for dilation devices. + +#### 3.3.7 Water drainage + +The following aspects should be considered: + +##### - *General* + +In most cases pipes will be naturally drained. The means that their level and slope can be adapted to tunnel layouts only within certain limits. + +##### - *Link between drain and tunnel* + +In view of the risk of backflow, there should be no open link between the drain and the tunnel. + +## 4 Safety plan + +### 4.1 Safety objectives + +Various aspects of safety should be considered: + +- safety of persons working in the tunnel; +- safety of persons and property outside the tunnel; +- security of distribution. + +For the first two items, safety objectives concern the risk of personal injury. + +Security of distribution is independent of personal safety. The importance of distribution ducts should not be overlooked, however, not only because of the convenience they provide to the public in general, but also because they may constitute in certain circumstances a vital factor of survival. + +### 4.2 Safety plan + +#### 4.2.1 Safety during the construction and installation phase + +The safety plan should comply with existing rules governing safety at work. Special attention should be paid to rules concerning construction work in enclosed spaces. In all cases, the maximum permissible levels of harmful substances or vapours, as defined by insurance companies, should not be exceeded. + +#### 4.2.2 Safety during the operational phase + +The company owning an installation should be responsible for issuing instructions to be observed from the start of operations. + +In the event of maintenance or extension work, the safety measures laid down for the construction phase should be observed. + +Fire risk and fire-fighting facilities should be established in consultation with the fire brigade. + +Tables A-1/L.11 and A-2/L.11 show a model of a safety plan in the operational phase, with an indication of possible preventive measures. + +The rules applicable to the construction of a tunnel, as described in § 5, should be established in the light of the safety plan. + +### 4.3 Special problems to be considered + +A special study of safety aspects should be made, where necessary, with regard to the following points: + +- interference between telecommunication lines and high voltage or d.c. railway lines; +- tunnel design; +- ventilation; +- thermal protection; +- water drainage; +- electrical installations; +- gas or fire detection systems. + +## 5 Construction + +### 5.1 Transversal cross-section + +#### 5.1.1 General + +The transversal cross-section of a tunnel comprises the following elements: + +- ducts and related facilities, including free spaces for repairs and maintenance; +- reserve spaces; +- duct intersections and junctions; +- service gangways. + +#### 5.1.2 *Positioning of ducts* + +Over and above assembly requirements, the following rules should be applied: + +##### – *Telecommunications and antenna cables* + +The following spaces should be observed in relation to power lines: + +- low voltage, up to 1000 V: 0.3 m +- high voltage with low induction: 0.3 m +- high voltage with high induction: to be determined +(rigid earthing systems) + +##### – *Power line ducts* + +Where cables are supported by brackets or racks, thermal and electromagnetic interaction should be taken into account. + +##### – *Natural gas ducts* + +These should be placed as high as possible in the tunnel. This will protect them against mechanical damage and in the event of a leak, gas will accumulate under the ceiling. + +##### – *Water ducts* + +These should be placed as low as possible in the cross-section, for which facilitates installation and anchoring. A further factor is that ambient temperature tends to be lower on the tunnel floor. + +#### 5.1.3 *Service gangway* + +In order to facilitate free and safe transit through the tunnel, no steps should be placed across the service gangway. + +Gangway dimensions should be subject to the following rules: + +- minimum width: 0.7 m +- minimum height: 1.9 m +- dimension of the largest element to be introduced in the gangway, plus at least 0.2 m. +- dimensions to be increased according to circumstances, particularly at bends, intersections and working alcoves. + +#### 5.1.4 *Transversal slope* + +A transversal slope should be provided for water drainage. + +#### 5.1.5 *Examples of tunnel profiles* + +Figures B-1/L.11 and B-2/L.11 represent circular and rectangular tunnel cross-sections respectively. They show how the available space can be divided among the different networks. + +### 5.2 *Openings, access and partitions* + +#### 5.2.1 *Openings for equipment* + +Openings large enough should be provided to introduce the largest pieces of equipment during assembly and maintenance work in the tunnel. The openings should be located directly above the service gangway. Further openings may be provided during construction, but these should be sealed off before operations begin. Access should be provided for delivery vehicles. + +#### 5.2.2 *Access doors for staff* + +Staff access points should be located in accordance with escapeways and alarms. Generally speaking, the distance between two access points should not exceed 500 m. The possibility of introducing emergency exits between access doors should be considered. + +Access doors should be arranged so that they cannot be obstructed nor allow water or fumes to enter. + +Equipment openings and staff access doors should be lockable and as leakproof as possible. + +#### 5.2.3 *Partitions* + +Careful consideration should be given to the arrangement of transversal partitions. These should all be compatible with escapeways and exits. + +#### 5.2.4 *Facilities for the transport of equipment and assembly accessories* + +The operational layout should make provision along the service gangway for transport facilities (e.g. ceiling-mounted rails), and for construction accessories (e.g. hooks for pullies and lifting gear or anchor ties for fixtures). + +### 5.3 *Supports and fixtures* + +#### 5.3.1 *Loads to be considered* + +The following requirements should be taken into account: + +##### – *Permanent loads* + +Permanent loads should be indicated in the operating plan. + +##### – *Lifting* + +All ducts should, generally speaking, be secured against lifting forces. + +##### – *Seismic effects* + +All ducts brackets, supports and cable racks should be able to resist the effects of seismic forces, in accordance with national standards. + +##### – *Explosions* + +The ducts and other contents of a tunnel may be strongly shaken by explosions. If the safety plan shows that essential ducts may be exposed to such overloading, it should be ensured that: + +- the operation of such ducts is not affected by breakage or deformation; +- no movement may occur which might wrench essential supply ducts off their supports or allow them to collide against tunnel walls or other part of the construction. + +Such risks may be avoided with the introduction of shockproof ties and an appropriate arrangement of ducts. Expert advice should be sought in such matters. + +#### 5.3.2 *Protection against corrosion* + +It is important to protect supports and ties against corrosion in view of the long life of installations (see § 3.2). + +### 5.4 *Transit points between tunnels and open ground* + +At points where ducts transit between tunnels and open ground, due account should be taken to relative movements which may occur between the two types of environment. + +Tunnel exit points should be as leakproof as possible, so as to avoid the penetration of gas or water in the tunnel. + +### 5.5 *Shut-off devices* + +Suitable care should be taken to position shut-off devices of gas, water, district heating and drainage water ducts, on either side of the tunnel wall. It should be possible to operate all such devices from outside. + +### 5.6 *Ventilation* + +#### 5.6.1 *Objectives and rules* + +Ventilation should comply with the following objectives: + +##### – *Environment* + +Power lines and district heating ducts give off heat. Insofar as such heat is not transferred to the surrounding ground through tunnel walls, cooling must be provided by ventilation. + +Controlled ventilation also provides a means of lowering air humidity and contributes to active protection against corrosion. + +##### – *Safety* + +As part of the safety plan, the aim of ventilation is to reduce the danger of explosion, to prevent the entry of vehicle exhaust gases and to maintain noxious fumes given off by welding or brazing at permitted working levels. + +#### 5.6.2 Ventilation systems + +The systems of ventilation are: + +##### - *Natural ventilation* + +Natural ventilation causes a draft which arises as a result of differences of temperature and pressure. In many cases natural ventilation will produce sufficient movement of air. + +##### - *Mechanical ventilation* + +With pressured mechanical ventilation, air from the outside is blown down the tunnel with a fan. Apart from the movement of air, this leads to an increase in pressure, which prevents dangerous gases from entering the tunnel. + +#### 5.6.3 Choice between natural and mechanical ventilation + +The criteria for the choice between ventilation systems are: + +##### - *Technical and safety criteria* + +Mechanical ventilation is generally needed in the following cases: + +- when old gas ducts, which may not be leakproof, run alongside the tunnel; +- if there is risk that toxic or inflammable materials may enter the tunnel. + +As far as operating safety is concerned, one advantage of natural ventilation is that since it relies on no mechanical or electrical component there is no risk of air circulation being stopped as a result of a breakdown. + +##### - *Technical environmental criteria* + +In shallow underground constructions, where the walls are in contact with the surrounding ground, internal temperature changes in the tunnel are offset by the thermal inertia of its surroundings. This is why natural ventilation is generally sufficient to provide the required environmental conditions. + +##### - *Protection against corrosion* + +A high level of humidity and especially condensation will speed up the corrosion of ducts and fixtures. A high level of humidity in a tunnel may be caused by: + +- the infiltration of water through the tunnel walls; +- bleeding or cleaning water; +- the cooling of warm humid air introduced from outside by ventilation. + +High relative humidity should be avoided by the evacuation of any outside water by the shortest route. Mechanical ventilation should be switched off if it starts introducing warm humid outside air into a cool tunnel, as long as this does not lead to any undue increase in other risks. + +#### 5.6.4 Dimensioning of mechanical ventilation + +The distribution of internal partitions should take account of ventilation sectors. + +##### - *Dimensions according to temperature limits* + +Temperature limits are generally determined according to physiological acceptable working conditions or according to the capacity of electricity ducts. Owing to the considerable effect of the surrounding terrain on heat transfer as well as thermal effects caused by the construction, relatively little cooling effect is produced by ventilation. Also, little effect is derived from the above-ground outside temperature. + +##### - *Dimensioning allowing for the possibility of gas leaks* + +The dimensioning of mechanical ventilation should allow in normal service for the possibility of slight leaks from the gas duct, provided that the concentration of gas is always maintained below the minimum explosive limit, with a sufficient margin of safety. + +#### 5.6.5 Indications concerning the installation of a ventilation system + +In the case of natural ventilation, the cross-section of air inlets will be determined mainly by the quantity of air required. + +Consideration should be given to providing suitable outlets on which mobile air extractors (such as those used by the fire brigade) may be attached to the event of a fault or special work. + +### 5.7 *Water drainage* + +#### 5.7.1 *Objective and rules* + +The objectives is to extract the following types of water: + +- groundwater and seepage water entering the tunnel owing to the permeability of the tunnel walls; +- tunnel cleaning water; +- water from the bleeding of water pipes; +- water from district heating ducts; +- water leaking from water pipes; +- condensation water. + +The drainage of water from a burst duct should be provided under the safety plan. + +The water drainage system should meet the following requirements: + +- there should be no passage of gas from the tunnel to the drainage pipe; +- no odours should pass from the ducts to the tunnel (traps should be provided). + +#### 5.7.2 *Internal network in the case of small quantities of excess water* + +The water drainage system will be similar to that of a building. If only small quantities of water are involved, a drainage channel may be provided if a tunnel is suitable inclined. + +#### 5.7.3 *Water drainage in the event of a burst duct* + +In the case of a burst duct, the normal drainage channel will usually be insufficient to drain off excess water, possibly on account of insufficient capacity in the drainage pipe to which the tunnel is connected. The safety plan should determine what sort of quantity of escaping water needs to be taken into consideration for removal by the tunnel drainage system, in conjunction with appropriate damming and diversion facilities. + +#### 5.7.4 *Water drainage through piping situated below the tunnel* + +This system allows water to be drained by the effect of gravity. Special care should be taken to prevent any backflow. + +#### 5.7.5 *Water drainage into piping situated above the invert level* + +In this case, water has to be pumped from a drainage well. The safety plan should indicate whether one or more pumps are needed. The same considerations apply to the provision of separate emergency drainage. An electric pump should be supplemented with a second pump, driven by a different power source. Some sort of signalling system should generally be provided. + +### 5.8 *Signalling systems* + +#### 5.8.1 *General* + +Signalling and alarm systems should be installed only if all active safety measures have been considered and are deemed to be inadequate. Signalling and alarm systems should be covered by the special safety plan, but it should be borne in mind that the effectiveness of such equipment is only limited and that it is costly to maintain. + +#### 5.8.2 *Gas alarm systems* + +These systems activate an alarm (signalled at access points) as soon as they detect a dangerous mixture of gas and air. In tunnels equipped with a ventilation system, the latter may be activated to dilute the mixture. Signalling systems, should be set so that the alarm is given at the latest when the gas concentration reaches 50 percent of the minimum detonation threshold. A system should be provided to ensure continuity of operation in the event of a power cut. All leaks should be detected. Detectors should be placed at regular intervals and if necessary above joints, valves, etc. + +Gas detectors are indispensable in the case of tunnels connected directly to buildings. Service entrances in buildings should be leakproof. If fixed gas detection systems are not provided or should fail to operate, the absence of explosive or toxic gases should be checked with portable instruments before entry to a tunnel. + +#### 5.8.3 *Flood alarm systems* + +Flood alarm systems should include floater switches placed at low points and in drainage wells, with additional floaters on different levels, thus setting off successive alarms. + +#### 5.8.4 *Fire alarm systems* + +The need for a fire alarm system should be considered on a case-by-case basis. + +### 5.9 *Other service installations* + +#### 5.9.1 *Telecommunication systems* + +Internal service communications should be provided for inspections and repairs. The choice will depend on the length of the tunnel, the frequency of inspections and the maintenance plans of different users. + +#### 5.9.2 *Electrical power supply* + +It may be necessary to use flameproof service equipment in the tunnel. + +#### 5.9.3 *Lighting* + +Tunnels should generally be equipped with a permanent electrical lighting system. An independent emergency lighting system should also be provided. + +#### 5.9.4 *Tunnel cleaning* + +The possibility of using clearing machinery should be considered at the outset (passage width, water taps). + +#### 5.9.5 *Marking and signalling* + +All obstacles and safety devices should be clearly marked (steps, emergency exits, direction of exit). Ducts should be identified with specific, clearly visible and durable marking. In complex tunnel systems, route markings should be provided to help persons unfamiliar with the layout to find their way. + +#### 5.9.6 *Rules of usage* + +Safety rules should be laid down for visits to the tunnel, drawing attention to communication, safety and evacuation facilities. + +## 6 **Standardization of plans for underground ducts in tunnels used jointly for pipelines and telecommunication cables** + +### 6.1 *Introduction* + +This section describes the graphic representation of underground ducts in joint trenches or tunnels. + +The graphic representation of underground ducts in joint tunnels is standardized in several countries, and this document therefore confines itself to a general presentation. The management of the network concerned is responsible for updating plans and documents. + +Plans must contain all particulars required for the operation, maintenance and extension of underground ducts, as well as for their protection and continual operation during repairs. + +### 6.2 *Terminology* + +The term **underground duct** is defined in this Recommendation to mean a vector for the distribution of a fluid, connecting the place of production with the place of consumption or drainage. It covers pipelines for electricity as well as telecommunication cables. + +### 6.3 *Field of application* + +Underground duct plans form part of a general information system. These ducts, whether situated in public or in private areas, constitute public networks for distribution and drainage and for the protection of the environment. + +### 6.4 *Rules applicable to underground duct plans* + +#### 6.4.1 *Scope of information* + +Underground duct plans must contain, for the benefit of their users, complete and up-to-date information on: + +- the characteristics of the various ducts; +- their location and level; +- their network connections. + +#### 6.4.2 *Characteristics* + +Plans must contain all the particulars required for the operation, maintenance and extension of underground ducts, as well as for their protection and continual operation during repairs; they must correspond to the particular features of each network. + +#### 6.4.3 *Location and level* + +It should be possible from the plans to determine the position of ducts and duct components accurately, to transpose it to other documents and to relate it unequivocally to official survey points. Measurements must be taken in conformity with current surveying rules. + +#### 6.4.4 *Network connections* + +It should be possible to determine from the plans how ducts are connected to the network to which they belong. Overall plans or diagrams will often be required. + +### 6.5 *Basic plan* + +#### 6.5.1 *Special rules* + +The basic plan provides the basic reference for underground duct plans. Its purpose is to map the layout of areas where ducts are situated. + +#### 6.5.2 *Contents* + +The basic plan essentially contains information on: + +- fixed points (triangulation points, base points, levelling points); +- property limits, frontiers; +- buildings; +- types and boundaries of crops. + +### 6.6 *Duct or network plans* + +#### 6.6.1 *Types of plan* + +The network plan contains references to all the equipment and telecommand devices of a distribution or drainage network. Network plans are of the following types: + +- drainage water; +- electricity; +- telecommunication installations; +- district heating; +- gas; +- collective antenna installations; +- water. + +#### 6.6.2 *Special rules* + +Every duct or network plan must meet the operational requirements of the network concerned. The following rules shall apply: + +- it must contain all legally required information; +- for ducts, it must give information on their development, construction, operation and maintenance; +- it must contain instructions for use in the event of breakdown or malfunction; +- it must supply operators and third parties with information on the location and level of ducts. + +#### 6.6.3 Contents + +A duct plan generally comprises the following data: + +##### *Geometric data* + +- duct location; +- duct level. + +##### *Duct data* + +- fluid transported; +- managing enterprise; +- function; +- type and content; +- profile; +- dimensions; +- material; +- operational condition; +- construction or duct components; +- identification. + +##### *Auxiliary installation data* + +- Protective devices. + +#### 6.6.4 Scale of plan + +The choice of scale depends on the density of ducts. The scale of the duct plan should correspond, if possible, to that of the basic plan drawn up in accordance with the survey. + +The following scales are recommended: 1:100, 1:200, 1:250 or 1:500, according to the concentration of buildings in the area. + +### 6.7 Preparation of plans + +#### 6.7.1 Definition + +By **preparation of plans and data management** the capture, updating, processing and representation of all data relating to underground ducts is understood. Any information system for underground ducts can thus be run either manually or by computer. + +#### 6.7.2 Surveys + +The principles of surveys are as follows: + +Whenever ducts are laid or altered, their location and, if necessary, their level should be surveyed. + +If excavations reveal ducts which were hitherto unknown or the location of which had been uncertain, these ducts must be surveyed. This rule also applies to ducts located by detection. + +#### 6.7.3 Accuracy of location + +The accuracy of the points used to locate ducts must comply with land survey rules. + +#### 6.7.4 Survey methods + +One of the following survey methods must be used: + +- polar coordinates; +- orthogonal coordinates; +- distance resection; +- prolongations. + +#### 6.7.5 *Procedure for preparing plans* + +- single-plan system. The basic plan and duct data should appear on the same medium. Ducts have to be copied onto the basic plan. +- system of separate superimposable plans. With this system, each level of data appears on a separate sheet. The basic plan, duct data and network data can appear as different data levels. + +#### 6.7.6 *Representation* + +Ducts are represented graphically by means of conventional signs described in special standards. + +#### 6.7.7 *Writing* + +Writing must be clearly legible and uniform and must be suitable for reduction and reproduction. + +### 6.8 *Use of data processing systems – General analysis* + +A very large volume of data on underground ducts needs to be captured, stored, updated, processed and reproduced, and they have to be extractable in different combinations. It is therefore advisable to use computer techniques, since this is the only way of establishing an integrated system of information on underground ducts. Such a system can meet various requirements, such as combining different data levels by the automatic process of separate superimposable plans; it can also produce extracts (plans, lists, etc.) with a diversified content. + +An underground duct information system has to be designed as a continuous sequence of operations, including data capture in the field or in the office, storing and processing, and printing out of plans and lists. + +### 6.9 *Maintaining plans up to date* + +#### 6.9.1 *Updating* + +Duct plans cannot fulfil their purpose unless they are constantly updated. The following principles should be observed: + +- data on new or modified ducts must be collected and processed as soon as work is completed; +- basic plans must be kept up to date. + +#### 6.9.2 *Access to localization data* + +Localization documents should be available for consultation at any time between the completion of duct laying and the entry of data in the plan. + +### 6.10 *Model plan* + +#### 6.10.1 *Content* + +The model plan in Annex C shows distribution duct pipelines in addition to transport duct tunnels. + +#### 6.10.2 *Graphic representation* + +The tunnels and pipelines should be drawn to scale, corresponding in width to the internal diameter of the tubes. + +#### 6.10.3 *Representation of ducts* + +Since so many ducts and cables are either hung, laid or fixed inside tunnels, it is not possible to represent each duct individually. They are therefore represented in cross-sections of the tunnel, which are placed next to the pipeline or on separate sheets with an indication of their location. + +Branches, splices, spurs and other details are entered either on the plans or in special files. The distribution ducts for the different fluids should be indicated by conventional signs. + +## ANNEX A + +(to Recommendation L.11) + +TABLE A-1/L.11 + +### **Safety plan against outside risks** + +| Risk | Consequences | Level of risk | Security requirements | Possible preventive measures a) | | | +|---------------------------------------------------|------------------------------------------------------------------|------------------------------------------------------------------------------------------------|------------------------------------|--------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------| +| | | | | At source | During construction | In service | +| Incoming gas from parallel ducts or intersections | Explosion, fire, asphyxia or poisoning | Rare
Caused only by a burst duct
Damage will be extensive (to persons, ducts and tunnel) | Same as for load-bearing structure | Sealing or replacing gas ducts | Sealing duct exit between tunnel and ground
Natural ventilation
Forced ventilation (tunnel under pressure)
Tunnel to be divided into segments, with fireproof partitions | Measure gas concentration before entering tunnel
Check gas concentration regularly | +| Incoming water from outside | Possibility of drowning
Damage to duct | Rare | Distribution security | Protection against flood water | Well-placed openings
Leakproof doors, trap-doors and covers
All pipes to be secured against upward thrust
Efficient water drainage system | Monitoring system | +| Unstable ground foundation | Duct bursts, particularly at transit point from tunnel to ground | Foreseeable effects | Same as for load-bearing structure | Consolidation of foundation ground | Flexible fixtures
Appropriate designs of duct transit points | Monitoring by measurement | + +a) The above list of preventive measures is not exhaustive. + +TABLE A-1/L.11 (continued) + +| Risk | Consequences | Level of risk | Security requirement | Possible preventive measures a) | | | +|-------------------------------------|------------------------------------------------------------------|----------------------------------------------------------------------|----------------------------------|--------------------------------------------|---------------------------------------------------------------------|---------------| +| | | | | At source | During construction | In service | +| Seismic tremors | Duct bursts, particularly at transit point from tunnel to ground | Variable possibility according to regions

Substantial effects | Continued operation of all ducts | | Tremor-resistant fixtures

Special design of duct exit points | | +| Effect of weapons, explosion impact | Duct bursts | In time of war, effects are likely to lead to serious damage | Continued operation of all ducts | | Shock-resistant fixtures

Appropriate design of duct exits | | +| Sabotage | Duct bursts
Explosion
Fire | Rare | Continued operation of all ducts | | Lockable entry points | Entry control | + +a) The above list of preventive measures is not exhaustive. + +TABLE A-2/L.11 + +### Safety plan for risks inherent in tunnel ducts + +| Description of risks | | Consequence | Level of risk | Security required | Possible preventive measures a) | | | +|----------------------|------------------------------------|---------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------|--------------------------------------------------|-----------------------------------------------------------------------|------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Network | Risk | | | | At source | During Construction | In service | +| Electricity | Fire, smoke | Physical injury
Duct bursts
Cables on fire
Destruction of anticorrosion protective coatings and insulation | Rare
Gives rise to personal risk and extensive material damage | For persons, same for load-bearing structures | Careful laying of ducts | Segments to be separated with fire-resistant partitions | Fire alarm system | +| | Toxic and corrosive fumes | Intoxication of persons
Damages to ducts and metal elements | | | Restricted use of PVC-coated ducts
Exclusion of PVC cable fixtures | | | +| | Oil leakage from oil-filled cables | Pollution of groundwater and spring water | Rare, gives rise to indirect personal risk | For persons, same as for load-bearing structures | Oil-filled cables to be placed as high as possible in tunnel | Oil drainage device | Monitoring of oil pressure | +| Gas | Explosion and fire due to leak | Physical injury
Duct bursts
Tunnel damage | Rare
Personal risk and extensive material damage | For persons, same as for load-bearing structures | Steel pipes to be used for ducts and welded joints to be checked | Natural ventilation
Mechanical ventilation
Gasproof and fireproof partitions | Regular checks for possible leak
Duct corrosion checks
Regular gas concentration measurement
Gas concentration to be measured at each inspection | +| | Presence of gas without explosion | Asphyxia and intoxication | Rare
Physical injury | | | | | + +a) The above list of preventive measures is not exhaustive. + +TABLE A-2/L.11 (continued) + +| Description of risks | | Consequence | Level of risk | Security required | Possible preventive measures a) | | | +|----------------------|-------------------------------------------------------|-------------------------------------------------------------------------------------------|--------------------------------------------------|--------------------------------------------------|-----------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------| +| Network | Risk | | | | At source | During Construction | In service | +| Water | Tunnel flooding due to duct burst | Possibility of drowning
Damaged ducts | Rare
Personal risk and little material damage | For persons, same as for load-bearing structures | Careful design and construction of installation | Strong fixtures
Automatic valves
Effective water drainage system
All pipes to be secured against upward pressure | Regular checks for possible leaks
Corrosion checks
Alarm system (with floater switch) | +| District heating | Escaping steam or hot water due to duct burst or leak | Physical injury
Duct bursts and other damage to ducts due to rapid rise of temperature | Rare
Extensive damage | For persons, same as for load-bearing structures | Careful installation of ducts | Shut-off valves at tunnel ends controlled from outside
Remotely controlled shut-off valves
Partitions | Alarm system | +| Drainage water | Partial flooding | Damage to ducts | Rare,
Little material damage | Limitation of material damage | Ducts to be placed above the highest water level | | | +| | Complete flooding of tunnel | Physical injury and material damage | Rare | For persons, same as for load-bearing structures | Leakproof and lockable access points and inspection holes | Ducts to be secured against upward pressure | | + +a) The above list of preventive measures is not exhaustive + +## ANNEX B + +(to Recommendation L.11) + +### Examples of tunnel profiles + +![Diagram of a circular tunnel cross-section showing various duct areas (T, E, G, O, C, A), lighting, service gangway, and water drainage channel. It also indicates minimum free width (0.7 m) and free height (1.9 m).](81a4cbf0b3c4cbc065efdf8f800dadde_img.jpg) + +The diagram illustrates a circular tunnel cross-section. It is divided into several zones: 'T' (Telecommunication duct area) on the left, 'C' (District heating duct area) above it, 'G' (Gas duct area) at the top, 'E' (Power duct area) on the right, 'O' (Water duct area) below 'E', and 'A' (Waste water duct area) at the bottom. A central 'Service gangway' is shown with a 'Free width min. 0.7 m' and 'Free height, min. 1.9 m'. Other features include 'Lighting' at the top, 'Space for duct intersections and junctions' at the top right, and a 'Water drainage channel' at the bottom right. The code 'T0600010-89' is noted at the bottom right of the diagram. + +Diagram of a circular tunnel cross-section showing various duct areas (T, E, G, O, C, A), lighting, service gangway, and water drainage channel. It also indicates minimum free width (0.7 m) and free height (1.9 m). + +- T Telecommunication duct area (in tubes) +- E Power duct area +- G Gas duct area +- O Water duct area +- C District heating duct area +- A Waste water duct area + +FIGURE B-1/L.11 + +Example of circular cross-section + +![Diagram of a rectangular cross-section of a service tunnel. The diagram shows a central 'Service gangway' with a 'Free width min. 0.7 m' and 'Free height min. 1.9 m'. To the left of the gangway are three stacked areas labeled T (top), C (middle), and A (bottom). To the right are three stacked areas labeled G (top), E (middle), and O (bottom). Above the gangway is a 'Lighting' fixture. Above the T and G areas are 'Space for junctions' and 'Space for duct intersections and junctions' respectively. A 'Water drainage channel' is shown at the bottom left. The entire structure is enclosed in a hatched border. A reference code 'T0600020-89' is present.](5b8a756d9a71c35f17db8bcb90b438a3_img.jpg) + +Diagram of a rectangular cross-section of a service tunnel. The diagram shows a central 'Service gangway' with a 'Free width min. 0.7 m' and 'Free height min. 1.9 m'. To the left of the gangway are three stacked areas labeled T (top), C (middle), and A (bottom). To the right are three stacked areas labeled G (top), E (middle), and O (bottom). Above the gangway is a 'Lighting' fixture. Above the T and G areas are 'Space for junctions' and 'Space for duct intersections and junctions' respectively. A 'Water drainage channel' is shown at the bottom left. The entire structure is enclosed in a hatched border. A reference code 'T0600020-89' is present. + +- T Telecommunication duct area (exposed cables) +- E Power duct area +- G Gas duct area +- O Water duct area +- C District heating duct area +- A Waste water duct area + +**FIGURE B-2/L.11** +**Example of rectangular cross-section** + +## ANNEX C + +(to Recommendation L.11) + +### Model plan + +![A technical drawing of a 'Model plan' showing various underground utility ducts and surface features. The plan includes a rectangular 'Transport ducts' section at the top with labels A, B, C, D, E, F, G, H. Below it are 'Distribution ducts' shown in cross-section. A circular duct section at the bottom contains labels A, B, C, D, E, F, G, H. The drawing also shows roads, buildings (labeled 275, 793, 794), and various numerical markers (29, 36). Arrows indicate the flow or direction of the ducts.](e180f2b5fcbe8001554a7c0677cd3f82_img.jpg) + +A technical drawing of a 'Model plan' showing various underground utility ducts and surface features. The plan includes a rectangular 'Transport ducts' section at the top with labels A, B, C, D, E, F, G, H. Below it are 'Distribution ducts' shown in cross-section. A circular duct section at the bottom contains labels A, B, C, D, E, F, G, H. The drawing also shows roads, buildings (labeled 275, 793, 794), and various numerical markers (29, 36). 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change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant + +Power feeding and energy storage + +--- + +**Impact on information and communication technology equipment architecture of multiple AC, –48 VDC or up to 400 VDC power inputs** + +![ITU logo](0538daaa5583c23e17db3a12f2281a55_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue circular emblem with a stylized globe and the letters 'ITU' in white. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +## **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|--------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| Infrastructure including node elements (except cables) | L.200-L.249 | +| General aspects and network design | L.250-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| Optical fibre cable maintenance | L.300-L.329 | +| Infrastructure maintenance | L.330-L.349 | +| Operation support and infrastructure management | L.350-L.379 | +| Disaster management | L.380-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1206 + +## Impact on information and communication technology equipment architecture of multiple AC, –48 VDC or up to 400 VDC power inputs + +## Summary + +Recommendation ITU-T L.1206 discusses multiple power supply interfaces to information and communication technology (ICT) equipment operated by dual power input feeds with combinations of standardized –48 Volt direct current (DC) or alternating current (AC) sources, or DC source up to 400 Volt interfaces. Operational voltage and interface characteristics are detailed in ITU-T Recommendations and European Telecommunications Standards Institute (ETSI) relevant standards. This Recommendation also includes some details on the power architecture within the ICT equipment between the ICT power interface and the ICT end load. + +## History\* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.1206 | 2017-07-29 | 5 | 11.1002/1000/13282 | +| 2.0 | ITU-T L.1206 | 2025-07-29 | 5 | 11.1002/1000/16427 | + +## Keywords + +Architecture, ICT, power feed, power input, power interface, up to 400 VDC, –48 VDC. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, and information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2025 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|---------------------------------------------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 2 | +| 3.1 Terms defined elsewhere ..... | 2 | +| 3.2 Terms defined in this Recommendation..... | 2 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 3 | +| 6 Definition and requirements of multiple power interface configuration at the input of ICT equipment..... | 3 | +| 6.1 Individual power interfaces used for multiple power interface configuration..... | 3 | +| 6.2 Multiple power interface configurations and requirements..... | 4 | +| 7 Combination dependence of A, A3 and A1 interfaces for multiple power feeds..... | 7 | +| 8 Backfeeding protection..... | 10 | +| Appendix I – Power input switch selector installation options..... | 12 | +| I.1 Switch selector installation and options for system interface connections .... | 12 | +| I.2 Switch selector installed within converter and interface connections..... | 13 | +| Appendix II – Switch selector – General functionality and requirements switch ..... | 15 | +| II.1 General description of the power input switch selector ..... | 15 | +| II.2 Input power monitoring ..... | 15 | +| Appendix III – Backfeeding protection ..... | 16 | +| III.1 Example of backfeeding protection..... | 16 | +| III.2 Battery test function ..... | 17 | +| Appendix IV – Example of upstream conversion for dual –48 V power feed configuration at input of ICT equipment..... | 18 | +| Bibliography..... | 19 | + +# Introduction + +With the advantage of the emerging up to 400 Volt DC (VDC) power distribution, along with the use of traditional alternating current (AC) and –48 VDC power distribution for networks and information and communication technology (ICT) power feeding, a new multiple power supply interface is defined as being a combination of the standardized AC and direct current (DC) power system interface at the inputs of ICT systems. + +The present Recommendation also provides details showing the ICT equipment front-end power architectures that include an on-board converter and the interconnection options between the converter and the ICT interface. These include switch selection and diode combiner solutions for multiple input feeds. + +With an increase in the variation of potential power feeds to ICT equipment, especially with the emergence of up to 400 VDC power networks, a clear indication of how a multiple input power feed is to be referenced and how these multiple power feeds can be best managed is crucial in ensuring that common and recognized approaches are adopted in the installation and configuration of future ICT equipment. + +Appendix I presents options for the installation of a switch selector within ICT equipment and its operational attributes targeted for its reliable operation. + +This Recommendation was developed jointly by the European Telecommunications Standards Institute (ETSI) and ITU-T Study Group 5 and is published respectively by ITU and ETSI as Recommendation ITU-T L.1206 (the present Recommendation) and ETSI Standard TS 103 531 [b-ETSI TS 103 531], which are technically equivalent. + +## Recommendation ITU-T L.1206 + +## Impact on information and communication technology equipment architecture of multiple AC, –48 VDC or up to 400 VDC power inputs + +# 1 Scope + +This Recommendation is applicable to the case of multiple power feeding configurations at the input of information and communication technology (ICT) equipment in ICT systems. + +It defines the requirements for the power inputs combination of the three power interfaces: A1 alternating current (AC), A (–48 Volt DC (VDC)), P or A3 (up to 400 VDC)) that could potentially be used single or in combination for each input. + +This Recommendation also provides details of the power structure within ICT equipment, between ICT equipment interfaces and ICT equipment system loads that are inclusive of system power converters. + +The input power configurations are categorized to allow for better understanding and identification of each new multiple power feeding interface, providing details of the impacts and benefits of adopting them. Information is also provided on the impact on battery test function when used with the different dual power input combinations. + +Lastly, requirements are given for avoiding the potential risk of voltage back feeding from one input to the other and for general isolation requirements in all multiple power feeding configurations. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a standalone document, the status of a Recommendation. + +- [[ITU-T L.1200](#)] Recommendation ITU-T L.1200 (2012), *Direct current power feeding interface up to 400 V at the input to telecommunication and ICT equipment*. +- [ETSI EN 300 132-1] ETSI EN 300 132-1 V2.2.1 (2022-11), *Environmental Engineering (EE); Power supply interface at the input to Information and Communication Technology (ICT) equipment; Part 1: Alternating Current (AC)*. +- [ETSI EN 300 132-2] ETSI EN 300 132-2 V2.7.1 (2022-09), *Environmental Engineering (EE); Power supply interface at the input of Information and Communication Technology (ICT) equipment; Part 2: –48 V Direct Current (DC)*. +- [ETSI EN 300 132-3] ETSI EN 300 132-3 V2.3.1 (2023-01), *Environmental Engineering (EE); Power supply interface at the input of Information and Communication Technology (ICT) equipment; Part 3: Up to 400 V Direct Current (DC)*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following term defined elsewhere: + +**3.1.1 hot standby** [b-ISO/IEC 2382]: Configuration in which a redundant functional unit can be immediately brought into service should the primary functional unit fail. + +NOTE 1 – Term and definition standardized by ISO/IEC [ISO/IEC 2382-14:1997]. + +NOTE 2 – A hot standby state may apply to redundant or stand-alone items. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 combined power feeding:** The function by which two power input feeds to information and communication technology (ICT) equipment are managed, such that one input is always available to power a single power module within the ICT equipment, e.g., by using the reverse bias characteristic of a two-diode common cathode module or a dual metal-oxide-semiconductor field-effect transistor (MOSFET). + +**3.2.2 combiner:** A device achieving the combined dependent power feed combination by diode or equivalent static electronic circuitry. + +**3.2.3 dependent power feed:** A power feed associated with a single interface on the information and communication technology (ICT) equipment but jointly associated with another power feed with a single power module within the ICT equipment via a managed power interface (switched or combined power feed). + +**3.2.4 independent power feed:** A power feed associated with a single interface on the information and communication technology (ICT) equipment and a single power module within the same ICT equipment used in a multiple power feeding interface. + +**3.2.5 switched power feeding:** A method by which two power input feeds to information and communication technology (ICT) equipment are managed, such that one input is always available to power a single power module within the ICT equipment with the use of a switch. + +**3.2.6 switch selector:** A device achieving the switched dependent power feed selection by a power switch. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|------------------------------| +| AC | Alternating Current | +| A+ | Pole plus of input A | +| A- | Pole minus of input A | +| ATS | Automatic Transfer Switch | +| B+ | Pole plus of input B | +| B- | Pole minus of input | +| BCONV | Converter | +| D | Diode | +| DC | Direct Current | +| EMI | Electromagnetic Interference | + +| | | +|----------|---------------------------------------------------| +| ICT | Information and Communication Technology | +| IGBT | Insulated Gate Bipolar Transistor | +| MOSFET | Metal-Oxide-Semiconductor Field-Effect Transistor | +| SwSelect | Switch Selector | +| VAC | Volt AC | +| VDC | Volt DC | + +# 5 Conventions + +This Recommendation uses the following conventions: + +**5.1 interface P:** ICT equipment up to 400 Volt DC (VDC) power interface as defined in [ITU-T L.1200]. + +**5.2 interface A1:** ICT equipment alternating current (AC) power interface as defined in [ETSI EN 300 132-1]. + +**5.3 interface A:** Terminals at which the –48 Volt DC (VDC) power supply is connected to the information and communication technology (ICT) equipment system block. + +NOTE – This convention is a "modified version" of the definition found in [b-ETSI EN 300 132-3-1] associated with Figure 1 and Annex A. This power interface is a functional concept and not an exact depiction of the physical location. + +**5.4 interface A3:** Terminals at which the up to 400 Volt DC (VDC) power supply is connected to the information and communication technology (ICT) equipment system block. + +NOTE – This convention is a "modified version" of the definition found in [b-ETSI EN 300 132-3-1] associated with Figure 1 and Annex A. This power interface is a functional concept and not an exact depiction of the physical location. + +# 6 Definition and requirements of multiple power interface configuration at the input of ICT equipment + +## 6.1 Individual power interfaces used for multiple power interface configuration + +The power supply interfaces presented in Figures 1 to 6 are the physical interconnection points to which all the requirements are related. This point is situated between the power supply system(s) and ICT equipment. + +Definitions of configurations in which "A", "P(A3)" and "A3ac" interfaces, presented as individual interface references, are shown in the following documents: + +- [ETSI EN 300 132-1], Annex B (AC supply) – A1 interface; +- [ETSI EN 300 132-2], Annex A (–48 VDC supply) – A interface; +- [ETSI EN 300 132-3], Annex B (400 VDC supply) – A3 interface; +- [ITU-T L.1200] – P interface (up to 400 VDC supply) equivalent to [ETSI EN 300 132-3], Annex B – A3 interface. + +NOTE – Subject to the installation preconditions, this point may be located at any other point between the power supply system and ICT equipment, by mutual agreement of the relevant parties. + +## 6.2 Multiple power interface configurations and requirements + +### 6.2.1 Identification of multiple interface input options + +For the case of multiple power interface configurations on ICT equipment (e.g., power supply unit with dual feeds), each power interface shall comply with at least one of the applicable standards detailed in clause 6.1. + +The multiple power interfaces shall be identified by using each of the individual interface definitions in sequence, for example, an ICT interface comprised of one AC supply (A1) and one AC supply (A1) shall be named A1/A1. + +In regard to the contents presented within this Recommendation, interfaces "A1/A1", "A1/A3", "A3/A3", "A1/A", "A/A", and "A/A3" are located at the power terminals of the ICT equipment or system as defined by the manufacturer in accordance with [b-IEC 60445]. + +Table 1 shows all of the interface options for multiple power feeds to ICT equipment. For simplification, the table makes the assumption of a maximum combination of two power feeds. Power interfaces will be configured for any ICT equipment installation and the individual interface shall be in accordance with the input power feed selected. + +**Table 1 – Interface configuration options for multiple power feeds to ICT equipment** + +| | AC | 400 VDC | –48 VDC | +|---------|---------------------|---------------------|--------------------| +| AC | A1/A1
(Figure 1) | A1/A3
(Figure 2) | A1/A
(Figure 4) | +| 400 VDC | A1/A3
(Figure 2) | A3/A3
(Figure 3) | A3/A
(Figure 6) | +| –48 VDC | A1/A
(Figure 4) | A3/A
(Figure 6) | A/A
(Figure 5) | + +### 6.2.2 Configuration AC / AC + +Figure 1 presents the interface A1/A1 for a multiple power feed consisting of two AC power feeds. The interface and operational voltage characteristics for an AC power feed are detailed in [ETSI EN 300 132-1]. + +![Diagram of the A1/A1 interface for dual AC inputs. It shows two AC power feeds entering a 'Telecom/Datacom (ICT) equipment' block. Each feed has terminals for Live (L), Neutral (N), and Protective Earth (PE). The first feed's terminals are connected to the top of the equipment block, and the second feed's terminals are connected to the bottom. The entire assembly is labeled as 'Interface "A1/A1"' at the bottom. A reference code 'L.1206(25)' is shown in the bottom right corner of the diagram area.](b0211cee4b20034939d883ac0d70f696_img.jpg) + +Diagram of the A1/A1 interface for dual AC inputs. It shows two AC power feeds entering a 'Telecom/Datacom (ICT) equipment' block. Each feed has terminals for Live (L), Neutral (N), and Protective Earth (PE). The first feed's terminals are connected to the top of the equipment block, and the second feed's terminals are connected to the bottom. The entire assembly is labeled as 'Interface "A1/A1"' at the bottom. A reference code 'L.1206(25)' is shown in the bottom right corner of the diagram area. + +**Figure 1 – General identification of the A1/A1 interface for multiple power feeds for dual AC inputs** + +### 6.2.3 Configuration AC / 400 VDC + +The AC interface and the interface for up to 400 VDC power feeds have the interface references of "A1" and "A3", respectively, and, as such, the combination of these two reference interfaces when used together on ICT equipment is presented as "A1/A3". The interface "A1/A3" for multiple power feeds consisting of one AC power feed and one up to 400 VDC power feed is shown in Figure 2. + +![Diagram of the A1/A3 interface for multiple power feeds (AC and up to 400 VDC).](e9314c83043183351ed74908e9bf2f90_img.jpg) + +The diagram shows a vertical bus representing the 'Interface "A1/A3"'. On the left, two groups of power feeds are connected to this bus. The top group, labeled 'AC', has three terminals: (L), (N), and (PE) (indicated by a dashed line). The bottom group, labeled '400 VDC', also has three terminals: (+), (-), and (PE) (indicated by a dashed line). On the right, a large rectangle represents the 'Telecom/datacom (ICT) equipment', which is connected to the bus. Below this rectangle, another rectangle labeled 'System block' is also connected to the bus. The reference 'L.1206(25)' is shown at the bottom right. + +Diagram of the A1/A3 interface for multiple power feeds (AC and up to 400 VDC). + +**Figure 2 – General identification of the A1/A3 interface for multiple power feeds for AC and up to 400 VDC inputs** + +The interface and operational voltage characteristics for an AC power feed shall be as detailed in [ETSI EN 300 132-1] and the interface and operational voltage characteristics for up to 400 VDC power feeds are detailed in [ETSI EN 300 132-3]. + +#### 6.2.4 Configuration 400 VDC / 400 VDC + +Figure 3 presents the interface "A3/A3" for a multiple power feed consisting of two, up to 400 VDC power feeds. The interface and operational voltage characteristics for up to 400 VDC power feeds are detailed in [ETSI EN 300 132-3]. + +![Diagram of the A3/A3 interface for multiple power feeds (dual of up to 400 VDC).](8e14350b4b669119a3bdfca7869110ca_img.jpg) + +The diagram shows a vertical bus representing the 'Interface "A3/A3"'. On the left, two identical groups of power feeds, each labeled '400 VDC', are connected to this bus. Each group has three terminals: (+), (-), and (PE) (indicated by a dashed line). On the right, a large rectangle represents the 'Telecom/datacom (ICT) equipment', which is connected to the bus. Below this rectangle, another rectangle labeled 'System block' is also connected to the bus. The reference 'L.1206(17)\_F03' is shown at the bottom right. + +Diagram of the A3/A3 interface for multiple power feeds (dual of up to 400 VDC). + +**Figure 3 – General identification of the A3/A3 interface for multiple power feeds for dual of up to 400 VDC inputs** + +### 6.2.5 Configuration AC / -48 VDC + +Figure 4 presents the interface "A1/A" for a multiple power feed consisting of one AC power feed and one -48 VDC power feed. In this instance, the AC and -48 VDC interfaces have interface structures that are termed "A1" and "A", respectively. + +![Diagram of the A1/A interface for AC and -48 VDC inputs.](042733dc5e8e7f5f30b60adba3266cde_img.jpg) + +The diagram shows a vertical dashed line representing the interface "A1/A". To the left of the interface, there are two groups of terminals. The top group is labeled "AC" and includes terminals (L), (N), and (PE) (indicated by a dashed line). The bottom group is labeled "-48 VDC" and includes terminals (+) and (-). To the right of the interface, a box labeled "Telecom/datacom (ICT) equipment" contains the top three terminals, and a box labeled "System block" contains the bottom two terminals. The reference "L.1206(25)" is shown at the bottom right. + +Diagram of the A1/A interface for AC and -48 VDC inputs. + +**Figure 4 – General identification of the A1/A interface for multiple power feeds for AC and -48 VDC inputs** + +The interface and operational voltage characteristics for an AC power feed shall be as detailed in [ETSI EN 300 132-1] and the interface and operational voltage characteristics for the -48 VDC power feed are detailed in [ETSI EN 300 132-2]. + +#### 6.2.6 Configuration -48 VDC / -48 VDC + +Figure 5 presents interface "A/A" for a multiple power feed consisting of two -48 VDC power feeds. The interface and operational voltage characteristics for a -48 VDC power feed are detailed in [ETSI EN 300 132-2]. + +![Diagram of the A/A interface for dual -48 VDC inputs.](853f59c89931a666c07903b31d098277_img.jpg) + +The diagram shows a vertical dashed line representing the interface "A/A". To the left of the interface, there are two groups of terminals, each labeled "-48 VDC". Each group includes terminals (+) and (-). To the right of the interface, a box labeled "Telecom/datacom (ICT) equipment" contains the top two terminals, and a box labeled "System block" contains the bottom two terminals. The reference "L.1206(17)\_F05" is shown at the bottom right. + +Diagram of the A/A interface for dual -48 VDC inputs. + +NOTE – It is possible that some energy conversion parts be upstream interface A. +See Appendix IV for detailed information. + +**Figure 5 – General identification of the A/A interface for multiple power feeds for dual -48 VDC inputs** + +#### 6.2.7 Configuration -48 VDC / 400 VDC + +Figure 6 presents interface "A3/A" for a multiple power feed consisting of one, up to 400 VDC power feed and one -48 VDC power feed. The -48 VDC interface and the interface for up to 400 VDC power feeds have the interface references of A and A3, respectively, and, as such, the combination of these two reference interfaces when used together on ICT equipment is presented as "A3/A". + +![Figure 6: General identification of the A3/A interface for multiple power feeds for up to 400 VDC and -48 VDC inputs. The diagram shows a vertical stack of terminals. The top three terminals are labeled (+), (-), and (PE) and are grouped by a bracket as '400 VDC'. The bottom two terminals are labeled (+) and (-) and are grouped by a bracket as '-48 VDC'. These terminals connect to a box labeled 'Telecom/datacom (ICT) equipment'. Below this box is another box labeled 'System block'. A dashed vertical line separates the terminals from the equipment boxes. Below the system block, the text 'Interface "A3/A"' is present. The identifier 'L.1206(17)_F06' is in the bottom right corner.](af7916c89a458fdab6c3f443217388ae_img.jpg) + +Figure 6: General identification of the A3/A interface for multiple power feeds for up to 400 VDC and -48 VDC inputs. The diagram shows a vertical stack of terminals. The top three terminals are labeled (+), (-), and (PE) and are grouped by a bracket as '400 VDC'. The bottom two terminals are labeled (+) and (-) and are grouped by a bracket as '-48 VDC'. These terminals connect to a box labeled 'Telecom/datacom (ICT) equipment'. Below this box is another box labeled 'System block'. A dashed vertical line separates the terminals from the equipment boxes. Below the system block, the text 'Interface "A3/A"' is present. The identifier 'L.1206(17)\_F06' is in the bottom right corner. + +**Figure 6 – General identification of the A3/A interface for multiple power feeds for up to 400 VDC and -48 VDC inputs** + +The interface and operational voltage characteristics for a -48 VDC power feed are detailed in [ETSI EN 300 132-2] and the interface and operational voltage characteristics for up to 400 VDC power feeds are detailed in [ETSI EN 300 132-3]. + +# 7 Combination dependence of A, A3 and A1 interfaces for multiple power feeds + +Table 2 presents alternate power architecture structures between the interfaces detailed in clause 6 and the load interface of the ICT equipment. The table shows that when there is a dependent power feed, a managed redundancy function is required for its proper operation. This can be clearly seen with the switched and combined input configurations presented (architectures 7 to 11). The power structures presented include the ICT equipment on-board power converters and any power management solutions that allow for the controlled supervision of the input powers presented at the ICT equipment interface, to ensure continued operation of the ICT equipment in the event of any one preferred input power feed failing. + +Table 2 shows that when there is a dependent power feed, a managed redundancy function is required for its proper operation. This can be clearly seen with the switched and combined input configurations presented (architectures 7 to 11). + +**Table 2 – Alternate power structures within ICT equipment between ICT power input interface and ICT equipment load inclusive of power converter** + +| System config | Supply configuration (Note 2) | Interface | Battery test | Power structure | Architecture | +|---------------|--------------------------------------------------------------|---------------------|--------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 1 | AC/AC
Direct power feed
Independent power feeds
(1) | A1/A1
(Figure 1) | Ok | Two separate AC power feeds to the ICT equipment detailed as A 1 and B 1 . Direct power feed connection from the ICT interface to a converter. Each converter and interface used in the ICT equipment is effectively doubled A 1 /A n and B 1 /B n . |

Image: Diagram for Table 2, Architecture 1. It shows a box for 'ICT equipment' with an 'Interface' at the bottom. Inside the box, there are four converters: 'Converter (a1)', 'Converter (b2)', 'Converter (an)', and 'Converter (bn)'. The first two are solid boxes, and the last two are dashed boxes. All four converters are connected to a common 'Load'. On the left, four AC input lines are labeled A1, An, B1, and Bn. Each line connects to an 'AC' input point on the corresponding converter. The identifier 'L.1206(17)_T2-1' is in the bottom right corner.

| + +**Table 2 – Alternate power structures within ICT equipment between ICT power input interface and ICT equipment load inclusive of power converter** + +| System config | Supply configuration (Note 2) | Interface | Battery test | Power structure | Architecture | +|---------------|--------------------------------------------------------------------------------------------|------------------|--------------|---------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 2 | AC/up to 400 VDC
Direct power feed
Independent power feeds (1) | A1/A3 (Figure 2) | Ok | One AC and one up to 400 VDC power feed to the ICT equipment (as for system configuration 1) |

Image: Diagram for System config 2 showing power architecture. Inputs A1 (AC) and A_n (400 VDC) connect to Converter (a1) and Converter (b2) respectively. Inputs B1 (AC) and B_n (400 VDC) connect to Converter (a_n) and Converter (b_n) respectively. All converters output to a common Load and ICT equipment. The diagram is labeled L.1206(17)_T2-2 and includes an 'Interface' label at the bottom.

Input

A1 — AC — Converter (a1) — Load

An — 400 VDC — Converter (b2) — Load

B1 — AC — Converter (an) — Load

Bn — 400 VDC — Converter (bn) — Load

ICT equipment

L.1206(17)_T2-2

Interface

| +| 3 | Up to 400 VDC/up to 400 VDC
Direct power feed
Independent power feeds (1) | A3/A3 (Figure 3) | Ok | Two separate up to 400 VDC power feeds to the ICT equipment (as for system configuration 1) |

Image: Diagram for System config 3 showing power architecture. Inputs A1 (400 VDC) and A_n (400 VDC) connect to Converter (a1) and Converter (b2) respectively. Inputs B1 (400 VDC) and B_n (400 VDC) connect to Converter (a_n) and Converter (b_n) respectively. All converters output to a common Load and ICT equipment. The diagram is labeled L.1206(17)_T2-3 and includes an 'Interface' label at the bottom.

Input

A1 — 400 VDC — Converter (a1) — Load

An — 400 VDC — Converter (b2) — Load

B1 — 400 VDC — Converter (an) — Load

Bn — 400 VDC — Converter (bn) — Load

ICT equipment

L.1206(17)_T2-3

Interface

| +| 4 | AC/–48 VDC
Direct power feed
Independent power feeds (1) | A1/A (Figure 4) | Ok | One AC and one –48 VDC power feed to the ICT equipment (as for system configuration 1) |

Image: Diagram for System config 4 showing power architecture. Inputs A1 (AC) and A_n (AC) connect to Converter (a1) and Converter (a_n) respectively. Inputs B1 (–48 VDC) and B_n (–48 VDC) connect to Converter (b1) and Converter (b_n) respectively. All converters output to a common Load and ICT equipment. The diagram is labeled L.1206(17)_T2-4 and includes an 'Interface' label at the bottom.

Input

A1 — AC — Converter (a1) — Load

An — AC — Converter (an) — Load

B1 — –48 VDC — Converter (b1) — Load

Bn — –48 VDC — Converter (bn) — Load

ICT equipment

L.1206(17)_T2-4

Interface

| +| 5 | Up to 400 VDC/–48 VDC
Direct power feed
Independent power feeds (1) | A3/A (Figure 6) | Ok | One up to 400 VDC and one –48 VDC power feed to the ICT equipment (as for system configuration 1) |

Image: Diagram for System config 5 showing power architecture. Inputs A1 (400 VDC) and A_n (400 VDC) connect to Converter (a1) and Converter (a_n) respectively. Inputs B1 (–48 VDC) and B_n (–48 VDC) connect to Converter (b1) and Converter (b_n) respectively. All converters output to a common Load and ICT equipment. The diagram is labeled L.1206(17)_T2-5 and includes an 'Interface' label at the bottom.

Input

A1 — 400 VDC — Converter (a1) — Load

An — 400 VDC — Converter (an) — Load

B1 — –48 VDC — Converter (b1) — Load

Bn — –48 VDC — Converter (bn) — Load

ICT equipment

L.1206(17)_T2-5

Interface

| + +**Table 2 – Alternate power structures within ICT equipment between ICT power input interface and ICT equipment load inclusive of power converter** + +| System config | Supply configuration (Note 2) | Interface | Battery test | Power structure | Architecture | +|---------------|-------------------------------------------------------------------------------------|---------------------|--------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 6 | –48 VDC/–48 VDC Direct power feed
Independent power feeds
(1) | A/A
(Figure 5) | Ok | Two separate –48 VDC power feeds to the ICT equipment
(as for system configuration 1) | Diagram for system configuration 6 showing two separate -48 VDC power feeds (A1, An and B1, Bn) entering the ICT equipment through an interface. Each feed connects to a converter (a1, bn) which then connects to a load. The converters are labeled Converter (a1), Converter (b2), Converter (an), and Converter (bn). The diagram is labeled L.1206(17)_T2-6. | +| 7 | AC/AC switch selection
Dependent power feeds
(2), (3) | A1/A1
(Figure 1) | Ok | Two separate AC power feeds to the ICT equipment detailed here as A 1 and B 1 . An input selection by a switch selector is placed between the ICT equipment power interface and one internal converter. A power feed from either ICT equipment interface is selected to power the converter. | Diagram for system configuration 7 showing two AC power feeds (A1, B1) entering the ICT equipment through an interface. A switch selector chooses between the two feeds to power a single converter, which then connects to a load. The diagram is labeled L.1206(17)_T2-7. | +| 8 | AC / up to 400 VDC switch selection
Dependent power feeds
(2), (3) | A1/A3
(Figure 2) | Ok | One AC and one up to 400 VDC power feed to the ICT equipment
(as for system configuration 7) | Diagram for system configuration 8 showing one AC power feed (A1) and one up to 400 VDC power feed (B1) entering the ICT equipment through an interface. A switch selector chooses between the two feeds to power a single converter, which then connects to a load. The diagram is labeled L.1206(17)_T2-8. | +| 9 | Up to 400 VDC / up to 400 VDC switch selection
Dependent power feeds
(2), (3) | A3/A3
(Figure 3) | Ok | Two separate up to 400 VDC power feeds to the ICT equipment
(as for system configuration 7) | Diagram for system configuration 9 showing two up to 400 VDC power feeds (A1, B1) entering the ICT equipment through an interface. A switch selector chooses between the two feeds to power a single converter, which then connects to a load. The diagram is labeled L.1206(17)_T2-9. | + +**Table 2 – Alternate power structures within ICT equipment between ICT power input interface and ICT equipment load inclusive of power converter** + +| System config | Supply configuration (Note 2) | Interface | Battery test | Power structure | Architecture | +|---------------|----------------------------------------------------------------------------------|---------------------|--------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 10 | –48 VDC/
–48 VDC diode combiner
Dependent power feeds
(2), (4) | A/A
(Figure 5) | No (Note 1) | Two separate –48 VDC power feeds to the ICT equipment detailed as A 1 and B 1 . A diode combiner is placed between the ICT equipment interface and one converter. The input power feed connected to the diode with the higher DC voltage potential is automatically selected as the main powering supply of the ICT equipment by reverse biasing the diode connected to the lower DC voltage potential. | Diagram for system configuration 10 showing two -48 VDC power feeds (A1, B1) entering a diode combiner. The output of the combiner goes to a converter (a1/b1) which is connected to a load. The entire assembly is labeled 'ICT equipment' and 'Interface'. Reference L.1206(17)_T2-10. | +| 11 | Up to 400 VDC/ up to 400 VDC diode combiner
Dependent power feeds
(2), (4) | A3/A3
(Figure 3) | No (Note 1) | Two separate up to 400 VDC power feeds to the ICT equipment (as for system configuration 10) | Diagram for system configuration 11 showing two up to 400 VDC power feeds (A1, B1) entering a diode combiner. The output of the combiner goes to a converter (a1/b1) which is connected to a load. The entire assembly is labeled 'ICT equipment' and 'Interface'. Reference L.1206(17)_T2-11. | + +NOTE 1 – The diode combiner configuration cannot be used in a single battery test scenario, as this configuration offers no isolation of the battery line under test. In order to achieve battery testing, a switch needs to be added in series with the diodes, such that each of the DC feeds can be isolated separately. + +NOTE 2 – The definitions of independent power feed, dependent power feed, switched power feeding, and combined power feeding are reported in this table as (a), (b) with a = 1 or 2, b = 3 or 4 where (1), (2), (3), (4) are described as follows: + +- (1) Independent power feeding is defined as a multiple power input interface feeding a set of power supplies coupled in parallel on their outputs to a single load within the ICT equipment. +- (2) Dependent power feeding is a multiple power input interface associated with a single load interface in the ICT equipment. The inputs are switched or combined in the managed power interfaces defined in (3) and (4), in order to power the single power supply within the ICT equipment. +- (3) Switched power feeding is a method by which two power inputs are managed such that one input is always available to power a single power module within the ICT equipment with the use of an input power switch selector. +- (4) Combined power feeding is a method by which two power inputs are managed such that one input is always available to power a single power module within the ICT equipment by using the reverse bias characteristic of a two-diode common cathode module. + +The mixed system configurations with dependent power feedings (switched or combined) that present either –48 VDC and up to 400 VDC or a –48 VDC and an AC supply are not considered as viable solutions and, as such, are not presented in Table 2. The main reason is that the voltage differential between the –48 VDC and the stated high voltage input supply in both these system configurations is too large to develop a practical ICT on-board converter. + +NOTE – When the combination of interfaces is implemented, considerations on safety are important. This is regulated by existing standards on electrical installation. + +# 8 Backfeeding protection + +When ICT equipment has more than one supply connection, there is the risk of backfeeding. In the context of multiple voltage feeding, backfeeding relates to a potential situation where a hazardous voltage from one live power input of the multiple power feed is fed back to another "dead" power input of the multiple power feed and, as such, may be hazardous to operators and/or service personnel. + +The ICT equipment shall prevent hazardous voltage from being present on the input terminals after interruption of the input power. + +The solution options for backfeed protection are as follows: + +- 1) option 1: basic insulation between different power inputs provided by mechanical isolation gap; +- 2) option 2: functional insulation between different power inputs with the addition of an automatic switch (isolation). The function of the automatic switch is to "open" after the interruption of the input power (see Appendix III). + +Table 3 describes the backfeed protection solution required for the configurations of ICT equipment's power input feeds. + +**Table 3 – Backfeeding protection requirement for multiple power feedings to ICT equipment** + +| Converter | Feeds | Input characteristic | Inputs | Backfeed protection | Possible supply sources | +|--------------------------------------------------------------------------------------------|-------------------|--------------------------------------|--------------------------|--------------------------------------------------------------------------------------------------|----------------------------| +| Converter $a_1 \dots a_n$ | Feed A or Feed B | Independent power feeding (1) (Note) | Individual power feeding | Default by converter design | -48 VDC, AC, up to 400 VDC | +| Converter $b_1 \dots a_n$ | | | | | | +| Converter x | Feed A and Feed B | Dependent power feedings (2) (Note) | Switched (3) (Note) | Requires additional preventative measures (justification in clause 8) | AC, up to 400 VDC | +| Converter x | Feed A and Feed B | Dependent power feedings (2) (Note) | Combined (4) (Note) | Requires additional preventative measures if hazardous voltages used (justification in clause 8) | -48 VDC, up to 400 VDC | +| NOTE – The configuration referred to as (n) in this table is defined in Note 2 of Table 2. | | | | | | + +# Appendix I + +## Power input switch selector installation options + +(This appendix does not form an integral part of this Recommendation.) + +This appendix presents several installation options for integration of the switch power feed selector within ICT equipment. These should be considered based on their merit for the site in terms of cost and product line and against any potential space-saving opportunities. + +### I.1 Switch selector installation and options for system interface connections + +Figure I.1 presents a proposal for the installation of a switch selector as a separate front module within the ICT equipment. The figure also shows the plug/socket interface options that would be used for this approach. In this proposal, the switch selector module is configured with hardwired "flying leads". Each of these leads is terminated in an appropriate interface plug/socket that allows for a direct connection to both the ICT equipment's incoming interface power sockets and the outgoing feed to the ICT equipment's on-board converter. The flying lead cable length used on the switch selector module can either be pre-set for a specific installation requirement or set at a length that allows for a more generic installation solution. + +![Figure I.1: Switch selector module with plug/socket hardwired cable flying leads allowing for installation to the ICT input power feed interfaces and the ICT on-board converter. The diagram shows a detailed internal view of the ICT equipment on the left and a simplified external connection view on the right.](8592a32c2fdf17c1e562f0ba6b7e8e1a_img.jpg) + +The diagram illustrates the internal and external connections of a switch selector module within ICT equipment. On the left, a detailed view shows the internal components: AC input A1 and AC input B1, an ICT connector interface, a Converter connector interface, a CONV1 (converter), a Voltage monitor, and a Load. A switch selector is shown connecting the AC inputs to the converter. On the right, a simplified view shows the external connections: ICT power interface, ATS hardwired with connection plug/socket, Converter interface, and a SwSelect (switch selector) module. The SwSelect module is connected to the ICT power interface plugs and the Converter interface socket via hardwired flying leads. + +Figure I.1: Switch selector module with plug/socket hardwired cable flying leads allowing for installation to the ICT input power feed interfaces and the ICT on-board converter. The diagram shows a detailed internal view of the ICT equipment on the left and a simplified external connection view on the right. + +L.1206(17)\_FI.1 + +**Figure I.1 – Switch selector module with plug/socket hardwired cable flying leads allowing for installation to the ICT input power feed interfaces and the ICT on-board converter** + +To provide further flexibility to the switch selector modules when installed as a separate front module within the ICT equipment, a further iteration would see "male" and "female" connectors placed onto the switch selector module itself (Figure I.2). In this way, the plug/socket connections become separate cable assemblies providing connection between the switch selector module and the ICT equipment/converter. The cable assemblies can be manufactured to meet specific installation requirements of the site or manufactured with common lengths allowing for a more generic installation solution. + +![Figure I.2: Switch selector module with plug/socket cable assemblies. The diagram shows an internal view of an ICT equipment on the left and an external view on the right. The internal view shows AC input A1 and DC input B1 connected to a 'Connector interface(s) on ATS and ICT', which then connects to a 'Connector interface(s) on ATS and converter'. This is followed by a 'Voltage monitor', a 'CONV1' (converter), and a 'Load'. The external view shows the 'ICT power interface' connected to a 'Switch selector with socket/plug interface and socket/plug cable feed connections'. This switch selector is connected to a 'Converter' via a 'Converter interface'. Below the switch selector, there is a 'SwSelect' box with two plug connections on it, labeled 'Plug connections on switch selector for plug/socket cable assemblies from ICT power inputs and to converter'. A note indicates that 'Interfaces to/from switch selector are shown as plug/socket'. The diagram is labeled 'L.1206(17)_FI.2'.](9c6461e1e94afae4dec455e69a2ce152_img.jpg) + +Figure I.2: Switch selector module with plug/socket cable assemblies. The diagram shows an internal view of an ICT equipment on the left and an external view on the right. The internal view shows AC input A1 and DC input B1 connected to a 'Connector interface(s) on ATS and ICT', which then connects to a 'Connector interface(s) on ATS and converter'. This is followed by a 'Voltage monitor', a 'CONV1' (converter), and a 'Load'. The external view shows the 'ICT power interface' connected to a 'Switch selector with socket/plug interface and socket/plug cable feed connections'. This switch selector is connected to a 'Converter' via a 'Converter interface'. Below the switch selector, there is a 'SwSelect' box with two plug connections on it, labeled 'Plug connections on switch selector for plug/socket cable assemblies from ICT power inputs and to converter'. A note indicates that 'Interfaces to/from switch selector are shown as plug/socket'. The diagram is labeled 'L.1206(17)\_FI.2'. + +**Figure I.2 – Switch selector module with plug/socket cable assemblies allowing for installation to the ICT input power feed interfaces and the ICT on-board converter** + +### I.2 Switch selector installed within converter and interface connections + +Figure I.3 presents a further alternative installation option of a switch selector. In this approach, the switch selector (separate front module) is moved out of the ICT equipment and placed within the ICT equipment on the converter electronic board. This provides some space-saving opportunities. + +As seen in Figure I.3, the interface at the ICT equipment is still present, but there are now two input interfaces placed onto the converter for the two separate input supplies to the ICT equipment. Plug/socket cable assemblies provide the connections from the ICT equipment's external power interfaces to the ICT equipment on the converter electronic board. + +This approach has advantages and disadvantages. The main advantage is in relation to the potential space saving within the ICT equipment by placing the switch selector module within the ICT on the converter electronic board. The disadvantage, however, is that the converter becomes quite specialized in its design, removing any system backward compatibility. In addition to this, the power interface for the converter becomes more complex (single to a dual power feed interface) which, along with the inclusion of the switch selector components, will impact the converter's cost and potentially its overall size. + +The advantages and disadvantages in taking this approach should be considered by the equipment provider on a "best case install basis" in terms of cost and potential space saved; however, after a further review of this solution, the disadvantages mentioned above clearly outweigh any potential advantages that could be gained. + +![Figure I.3: Switch selector on the ICT converter electronic board. The diagram shows the internal components of an ICT (AC input A1, AC input B1, ICT connector interface, CONV, Voltage monitor, Load) and its external connection to a Converter via a Plug/socket cable assembly. A detailed view of the CONV unit shows a switch selector with two plug connections for the cable assemblies.](b6671cfafda3820aafe9a24fa7a4d8c7_img.jpg) + +The diagram illustrates the internal architecture of an ICT and its external power connection. On the left, a large rectangle represents the ICT enclosure, containing 'AC input A1', 'AC input B1', an 'ICT connector interface', a 'CONV' (converter) unit, a 'Voltage monitor', and a 'Load'. The 'CONV' unit is shown in a detailed view, featuring a switch selector with two positions. To the right, the 'ICT power interface' is connected to a 'Plug/socket cable assembly', which in turn connects to the 'Converter' through a 'Converter interface'. Below the main diagram, a separate view of the 'Conv' unit shows two plug connections on its switch selector, labeled 'Plug connections on switch selector for plug/socket cable assemblies from ICT power inputs'. A note indicates a 'Switch selector incorporated into converter with plug/socket interface'. + +Figure I.3: Switch selector on the ICT converter electronic board. The diagram shows the internal components of an ICT (AC input A1, AC input B1, ICT connector interface, CONV, Voltage monitor, Load) and its external connection to a Converter via a Plug/socket cable assembly. A detailed view of the CONV unit shows a switch selector with two plug connections for the cable assemblies. + +**Figure I.3 – Switch selector placed on the ICT converter electronic board with cable assemblies allowing for connection from ICT power feed interfaces to the ICT on-board converter** + +L.1206(17)\_FI.3 + +## Appendix II + +## Switch selector – General functionality and requirements switch + +(This appendix does not form an integral part of this Recommendation.) + +### II.1 General description of the power input switch selector + +For the benefit of the reader, the term "switch selector", when used in the present document, can include, but is not inclusive of, the following functions: + +- Actuator – Provides the drive for the switch selector. +- Actuator drive circuitry. +- Voltage monitoring – Monitors the incoming voltage supplies and provides a signal at the instance of supply voltage failure. +- Control logic – Provides control and switch management. +- Switch contacts. +- Semi-conductor contact management – Can provide some additional control management of the switch contacts. + +The switch selector can comprise, but is not limited to, a number of functional elements, as listed above. In addition, the switch selector should include a voltage detection circuit. The purpose of this circuit is to monitor the incoming voltage supply rail(s) providing a signal to a switch selector actuator at the instance of a voltage failure being detected. The voltage detection circuit should be able to detect an incoming supply voltage failure on multiple AC/AC, DC/DC or any combination thereof. + +The switch selector shall also include control/switch management functions to ensure that the switch not only operates in line with the converter hold-up time but carries out this function in a controlled manner ensuring high levels of reliability. The switch selector could also include additional semi-conductor devices that may assist in its clean switch management. + +The switch selector shall be fully compliant with creepage and clearance and voltage backfeed regulatory safety requirements at the targeted operational voltages. This shall include any additional protection circuitry required for its intended operational environment. This could include, but not be limited to, any electromagnetic interference (EMI) filtering and transient suppression necessary to comply with local or international regulatory standards. + +### II.2 Input power monitoring + +The switch selector needs to be activated when an instance of an input voltage supply failure is detected. To ensure optimal performance, monitoring circuitry that can provide this function to a high level of reliability and accuracy should be included in its design. + +The monitor interface should be capable of detecting multiple AC/AC, DC/DC or a mixture of both voltage types at voltage levels of 230 Volt AC (VAC) and up to 400 VDC. + +The maximum switching time of the switch selector should be compatible with the ICT on-board converter hold-up time, i.e., between 10 ms and 20 ms. + +The voltage monitoring solution needs to provide a high level of immunity to any transient voltage events on the monitored incoming supplies and thus avoid any erratic toggling of the switch selector. In addition, the monitoring circuitry should also provide full immunity to any extraneous high voltage events that could potentially damage its operation. + +## Appendix III + +## Backfeeding protection + +(This appendix does not form an integral part of this Recommendation.) + +### III.1 Example of backfeeding protection + +For the two backfeeding protection methods listed in clause 8, the second method (2) is presented as an example below. + +For this example, the DC operated equipment has at least two DC inputs, of which both inputs are combined by the combiner module. + +The combiner modules consist of D1, D2, D3 and D4, as detailed in Figure III.1. In this example, the components are presented as diodes but can be replaced by a component that can provide the combiner function, which would include MOSFETs or insulated gate bipolar transistors (IGBTs). These particular devices provide the additional benefit of reduced power dissipation when compared with the diode but come with the disadvantage of requiring a more complex drive/control interface. Placing two of these devices in a back-to-back configuration allows for complete control of the combiner function, i.e., providing full on/off functionality (Figure III.2). These components provide a functional insulation between the different power inputs. + +In addition to the combiner module, an automatic switch (isolation) module is presented and placed in series with each DC input circuit. The automatic switch (isolation) module includes a switch element and a switch element control circuit. + +The switch element used can take the form of a relay or any other component that offers a similar function, in that it shall provide a mechanical isolation that meets the functional insulation requirements. + +In application, the switch element control circuit detects if power is present at interface (A+/A $-$ , or B+/B $-$ ). If power is detected, then the switch element sets to the "on" position; conversely, if power is not detected at these inputs, then the respective switch element sets to the "off" position. In this way, the switch element ensures that, if the external supplies to the ICT equipment are removed or interrupted, the switch element contacts open, preventing any instance of voltage backfeeding to the respective disconnected input. + +![Circuit configuration for backfeeding protection when using a diode combiner interface for ICT equipment. The diagram shows DC equipment with two input lines, B- and A+, connected through mechanical switches K1 and K2. Each input line passes through an 'Automatic switch (isolation) module' containing a 'Switch element' and a 'Switch element control circuit'. The outputs of these modules are connected to a 'Combiner module' containing four diodes (D1, D2, D3, D4) arranged in a bridge configuration. The output of the combiner module is connected to a 'Load'. The diagram is labeled L.1206(17)_FIII.1.](c914f51f4427bc672dd0526cfc90ebe9_img.jpg) + +Circuit configuration for backfeeding protection when using a diode combiner interface for ICT equipment. The diagram shows DC equipment with two input lines, B- and A+, connected through mechanical switches K1 and K2. Each input line passes through an 'Automatic switch (isolation) module' containing a 'Switch element' and a 'Switch element control circuit'. The outputs of these modules are connected to a 'Combiner module' containing four diodes (D1, D2, D3, D4) arranged in a bridge configuration. The output of the combiner module is connected to a 'Load'. The diagram is labeled L.1206(17)\_FIII.1. + +**Figure III.1 – Circuit configuration for backfeeding protection when using a diode combiner interface for ICT equipment** + +![Back-to-back MOSFET replacement for diode module combiner providing a control on/off functionality. The diagram shows two MOSFETs connected back-to-back at their source terminals. The gates of the MOSFETs are connected to a common control input. The diagram is labeled L.1206(17)_FIII.2.](d734a6ea1b381280f043fcf70391b6db_img.jpg) + +Back-to-back MOSFET replacement for diode module combiner providing a control on/off functionality. The diagram shows two MOSFETs connected back-to-back at their source terminals. The gates of the MOSFETs are connected to a common control input. The diagram is labeled L.1206(17)\_FIII.2. + +**Figure III.2 – Back-to-back MOSFET replacement for diode module combiner providing a control on/off functionality** + +### III.2 Battery test function + +In addition to providing backfeeding protection, the circuit configuration presented in Figure III.1 can also provide the correct conditions for a battery test function to be carried out. With respect to Figure III.1, this test scenario would use the battery back-up input power line disconnected using either one of the mechanical switch modules as appropriate. + +In this instance, the switch modules detailed as "automatic" would also be implemented with an operational override control function to open the respective switch module contacts. Operator care or additional functional voltage monitoring would also be required to ensure that the supply of voltages to the ICT equipment remains within the operational voltage window, preventing any possibility of system shutdown during the battery test procedure. + +As an alternative, where combiner diodes D1 to D4, detailed in Figure III.1, are replaced with back-to-back MOSFETs (Figure III.2), the battery test function can be carried out by switching off the associated diode pairs. + +## Appendix IV + +## Example of upstream conversion for dual –48 V power feed configuration at input of ICT equipment + +(This appendix does not form an integral part of this Recommendation.) + +The proposed architecture is an example of an upstream conversion of AC (A1)/A (–48 VDC) and up to 400 VDC (A3)/A (–48 V) for dual input ICT equipment, as shown in Figure IV.1. + +The upstream power system can consist of a rack-level switching mode power supply in power cabinets. This may form a dual-partition power system feeding the –48 V dual power inputs to the ICT equipment. The cabinet can be common to several dual inputs. + +![Figure IV.1: Architecture of upstream AC and up to 400 VDC power system with rack-level power supply feeding in –48 VDC dual power input equipment in A/A configuration. The diagram shows a 'Rack-level power supply' block receiving two inputs: 'Up to 400 VDC input' and 'AC input'. It has two outputs, both labeled '-48 VDC', which connect to an 'Input interface' block. The 'Input interface' block is connected to a 'Load' block. The diagram is labeled 'L.1206(25)' at the bottom right.](7e1c9b51e067a48cd0fcc9748d8bd8d8_img.jpg) + +``` +graph LR; Input1[Up to 400 VDC input] --> RLPS[Rack-level power supply]; Input2[AC input] --> RLPS; RLPS -- "-48 VDC" --> II[Input interface]; RLPS -- "-48 VDC" --> II; II --> Load[Load]; +``` + +Figure IV.1: Architecture of upstream AC and up to 400 VDC power system with rack-level power supply feeding in –48 VDC dual power input equipment in A/A configuration. The diagram shows a 'Rack-level power supply' block receiving two inputs: 'Up to 400 VDC input' and 'AC input'. It has two outputs, both labeled '-48 VDC', which connect to an 'Input interface' block. The 'Input interface' block is connected to a 'Load' block. The diagram is labeled 'L.1206(25)' at the bottom right. + +**Figure IV.1 – Architecture of upstream AC and up to 400 VDC power system with rack-level power supply feeding in –48 VDC dual power input equipment in A/A configuration** + +The dual-partition power supply system has two independent inputs and outputs and may have a unified monitoring module. The two inputs can be an AC and an up to 400 VDC interface. The outputs of the power supply are two separate –48 VDC lines compatible with the existing ICT equipment in the telecommunication centre. + +The dual-partition power supply system can have a variety of operating modes as follows: + +- 1) the main power is provided by the AC partition while using up to 400 VDC in hot standby mode; +- 2) the main power is provided by the up to 400 VDC partition while using AC in hot standby mode; +- 3) the power is equally shared between AC and up to 400 VDC partitions. + +Several differences can be identified between configurations with external power supply system and dual input power supply solution embedded in ICT equipment, as shown in Figure IV.1. + +- 1) the capacity of an independent power supply should be at the same level; +- 2) there is only one control/monitoring module which manages and coordinates the operating parameters of the power modules of both partitions; +- 3) the input of the two partitions are an AC input and an up to 400 VDC input which should be completely isolated; +- 4) the output voltages of the two partitions are –48 VDC and should be isolated, but each single partition output voltage can be adjusted according to the load; +- 5) dual-partition embedded switching mode power supply can have a variety of working modes. + +## Bibliography + +- [b-ETSI TS 103 531] ETSI TS 103 531 V1.2.1 (2024-01), *Environmental Engineering (EE); Impact on ICT equipment architecture of multiple AC, –48 VDC or up to 400 VDC power inputs.* +- [b-ETSI EN 300 132-3-1] ETSI EN 300 132-3-1 V2.1.1 (2011-10), *Environmental Engineering (EE); Power supply interface at the input to telecommunications and datacom (ICT) equipment; Part 3: Operated by rectified current source, alternating current source or direct current source up to 400 V; Sub-part 1: Direct current source up to 400 V* +- [b-IEC 60445] IEC 60445:2017, *Basic and safety principles for man-machine interface, marking and identification – Identification of equipment terminals, conductor terminations and conductors.* +- [b-ISO/IEC 2382] ISO/IEC 2382:2015, *Information technology – Vocabulary.* + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, 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b/marked/L/T-REC-L.1220-201708-I_PDF-E/raw.md @@ -0,0 +1,954 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.1220** + +(08/2017) + +SERIES L: ENVIRONMENT AND ICTS, CLIMATE +CHANGE, E-WASTE, ENERGY EFFICIENCY; +CONSTRUCTION, INSTALLATION AND PROTECTION +OF CABLES AND OTHER ELEMENTS OF OUTSIDE +PLANT + +--- + +**Innovative energy storage technology for +stationary use – Part 1: Overview of energy +storage** + +Recommendation ITU-T L.1220 + +# ITU-T L-SERIES RECOMMENDATIONS + +## **ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT** + +| | | +|-------------------------------------------------------|-------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node element (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1220 + +# Innovative energy storage technology for stationary use – Part 1: Overview of energy storage + +## Summary + +Recommendation ITU-T L.1220 introduces an open series of documents for different families of technologies (e.g., battery systems, super-capacitor systems) that will be enriched progressively as new technologies emerge that may significantly impact the field of energy storage. + +With the increase of new technologies in energy storage there is need for a global overview of an energy storage system for use in stationary information and communication technology (ICT) installations in networks, data centres and customer premises equipment (CPE), and simple evaluation of acceptable duration and characterization methods for this specific purpose. + +Identified parts of this Recommendation series, Innovative energy storage technology for stationary use, are: + +- Part 1: Overview of energy storage; +- Part 2: Battery systems; +- Part 3: Supercapacitor technology. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.1220 | 2017-08-13 | 5 | 11.1002/1000/13283 | + +## Keywords + +Battery, direct current, double layer capacitor, energy storage, rechargeable battery, secondary battery, supercapacitor. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2017 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | | Page | +|-----|--------------------------------------------------------------------------------------------------------------------------------------|------| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 3.1 | Terms defined elsewhere ..... | 2 | +| 3.2 | Terms defined in this Recommendation..... | 2 | +| 4 | Abbreviations and acronyms ..... | 3 | +| 5 | Conventions ..... | 3 | +| 5.1 | A (interface)..... | 3 | +| 5.2 | A3 (interface)..... | 4 | +| 6 | General introduction of the need for electrical energy storage..... | 4 | +| 6.1 | Short disturbance and dips filtering..... | 4 | +| 6.2 | Increased reliability by adding autonomy to cover prolonged grid outages .. | 4 | +| 6.3 | Self-consumption of renewable energy increased by storage for on-grid
and off-grid systems ..... | 4 | +| 6.4 | Smart grid services with energy storage functionality and possible
reliability increase ..... | 4 | +| 6.5 | Machine-to-machine and Internet of Things devices power supply ..... | 5 | +| 6.6 | Voltage interface of energy storage solutions ..... | 5 | +| 7 | Evolution of energy storage..... | 5 | +| 8 | Selection method of energy storage for ICT stationary use ..... | 7 | +| 8.1 | Selection method based on general criteria and complementary tests ..... | 7 | +| 8.2 | Detailed description of the main parameters of energy storage technology... | 8 | +| 9 | Test methods..... | 10 | +| 9.1 | General introduction..... | 10 | +| 9.2 | Test flowchart..... | 10 | +| 9.3 | Additional considerations..... | 12 | +| | Appendix I – Energy storage (battery, supercapacitor) world-market evolution ..... | 13 | +| | Appendix II – Multi-criteria approach to choosing energy storage ..... | 14 | +| | Appendix III – Rationale for very short autonomy on good grids obtained by
supercapacitor or high-power rechargeable battery..... | 18 | +| | Bibliography..... | 22 | + +# Introduction + +Until early 2000, battery technology has been dominated by lead-acid for stationary and motive uses (e.g., factory fork lifts, engine starters). Nickel-metal hydride (NiMH) and lithium have been used for mobile devices, portable tools and partially for electric vehicles. They have also been used for highly reliable and secure applications in fields such as industry, transport, etc. + +The recent and relatively fast evolution of batteries, in particular lithium-ion, has been driven by the rapid development of electric cars for urban use in fleets and more recently for popular commuter use in vehicles for public and private transport. The latest battery research has been directed toward technology enhancements that support an increase in distance travelled by vehicles using a single charge and a reduction in the time taken to re-charge the battery. Vehicle battery technology is rapidly expanding to include other battery technology areas offering product advantages in terms of reduced cost, safety, higher energy density levels and quicker charging. These include solid state batteries, aluminum ion, lithium sulfur and metal air. These strong developments of battery technologies can be applied to the stationary information and communication technology (ICT) industry. + +An energy storage and generation technology that appears to move in and out of the battery lime light is the fuel cell. This technology comes in various assortments, but is best known as the hydrogen fuel cell for which a very high-power density of $0.7 \text{ W.cm}^{-2}$ , or higher, is possible, depending on operating conditions. Car manufacturers are considering extending the range of batteries with general optimization in hybrid solutions for fuel cells, or internal and external engine generators. Fuel cell technology remains a potential contender for future use by electric vehicle manufacturers. Fuel cells have also been used in several ICT site trials and installations by major telecom providers. + +The European Union (EU) Renewable energy directive () states that the EU is to meet at least 20% of its total energy needs with renewable energy by 2020. This is to be achieved through the attainment of individual national targets by member states. + +In a revision of the directive, the EU targets at least 27% renewable energy of their final energy consumption by 2030. + +Depending on the energy mix, the existing electric grid can accept an average injection of up to 10 to 30% of renewable energy by only adding big regional energy storages. For example, water pumped-storage hydroelectricity (PSH) or air compressed energy storage CAES connected to the high-voltage grid. Above this level of intermittent renewable energy, in some places or more generally in regions or countries, there is a need for smaller local storages, in general, made of electrochemical batteries. Statistical analysis carried out within the EU in 2014 showed that 25.4% of its total primary energy production came from renewables. This was made up of 16% biofuels, 4.2% hydropower, 2.83% wind and 1.55% solar. These technologies were further augmented with large regional energy storage solutions such as water PSH and CAES, both solutions offering peak time energy stability to the high-voltage grid. Although the EU can boast of having very high levels of renewable energy solutions, there is a need to further support these solutions in some regions where large renewable energies are still in development or offer intermittent or limited energy supply. This point is particularly true in some countries outside of EU borders where there is a need for smaller local storage solutions. In general, these solutions comprise of electro-chemical batteries. + +In an attempt to make ICT sites more autonomous or interactive with the local utilities (e.g., peak shaving, demand response), local battery installations are offering 'self-consumption' of renewable energy. This is achieved by charging local battery stacks using solar technology and, as such, providing site power at night and in periods of bad weather. In these particular examples, there is a need to move away from pure back-up float batteries to cyclic batteries, and in addition where site power requirements dictate, short-term storage solutions, such as supercapacitors, should be considered. + +With the development of new sectors, such as Internet of Things (IoT) and machine-to-machine (M2M) technologies, uninterrupted stationary energy supplies have become more and more important where energy consumption is too great for using primary batteries given their size, cost and frequency of replacement. Therefore, rechargeable batteries are necessary for resilience and energy harvesting. + +Further information on all these subjects can be found in various studies on energy storage such as [b-IEC WPstorage] and other presentations and publications such as [b-IRES + ESE 2016-T&E], [b-ETSI EE 2015-storage solutions], [b-Elsevier 2016-ESS applications], [b-battery BU-107], [b-battery BU-205], [b-ENEA], [b-Soogreen]. + +The trend toward the use of more cyclic battery technologies and supercapacitors is illustrated in the international battery market evolution presented in Appendix I. + +To this end, and to facilitate the choice of adapted storage solutions for stationary use in the ICT sector, simple and effective methods were developed in this series of Recommendations. They should give results in a reasonable time period, introduced in this Recommendation. + +Detailed information and test methods will be given in the next parts for each family of technologies which are under development, i.e., Part 2 and Part 3. + +Future possible parts could refer to other storage technologies (e.g., fuel cells, mechanical storage). + +With an increase in the selection of various manufacturers offering energy storage systems with different battery and supercapacitor technologies, it has become increasingly difficult for a designer and user to make the correct selection for their end system. + +The intention of these evaluation methods is not as a substitute for, but rather to complement the IEC standards on batteries on energy storage safety, factory tests, etc. These standards include [b-IEC 60896-X] for stationary lead-acid batteries, [b-IEC 62619] and [b-IEC 62620] for alkaline batteries or other non-acid electrolyte batteries, or further work on new energy storage technologies (e.g., other battery technologies, fly-wheel). Other useful IEC standards defining basic rules of graphical marking or other basic electrical safety are also listed in the bibliography. + +This Recommendation was developed jointly by ETSI TC EE and ITU-T Study Group 5, and is respectively published by ITU and ETSI as Recommendation ITU-T L.1220 and ETSI Standard ETSI TS 103 553-1, which are technically equivalent. + + + +# Recommendation ITU-T L.1220 + +## Innovative energy storage technology for stationary use – Part 1: Overview of energy storage + +# 1 Scope + +This Recommendation identifies the main needs and applications of stationary electrical energy storage for information and communication technology (ICT) sites such as back-up on different grid quality and cyclic use of renewable energy systems. It also provides possible selection criteria for the correct choice for the end system. The topics considered are: + +- families of electrical energy storage, such as batteries or supercapacitors; +- technologies types and their main properties; +- adaptation to requirements (e.g., functionalities, technology availability, electrical characteristics, environmental adaptation, maintenance type, cost); +- national or regional rules and regulations. + +The Recommendation highlights the need for evaluation methods that are complementary to existing battery standards as they allow different time-frames including shorter tests compared to common energy storage industry tests. + +This Recommendation is Part 1 of a series of Recommendations that cover energy storage technologies (e.g., battery, supercapacitor) applicable to stationary telecom/ICT equipment used in telecom networks, data centres and customer premises equipment (CPE). + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T L.1001] Recommendation ITU-T L.1001 (2012), *External universal power adapter solutions for stationary information and communication technology devices*. +- [ITU-T L.1200] Recommendation ITU-T L.1200 (2012), *Direct current power feeding interface up to 400 V at the input to telecommunication and ICT equipment*. +- [ETSI EN 300 132-2] ETSI EN 300 132-2 V2.3.6 (2011), *Environmental Engineering (EE); Power supply interface at the input to telecommunications and datacom (ICT) equipment; Part 2: Operated by –48 V direct current (dc)*. + +# 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 electrical equipment** [b-IEC 60050-826]: Item used for purposes like storage, generation, conversion, distribution or utilization of electric energy (e.g., electrical machines, transformers, switch gear and control gear, measuring instruments, wiring systems, current-using equipment, etc.). + +**3.1.2 ICT equipment** [ITU-T L.1200]: Information and communication equipment (e.g., switch, transmitter, router, server, and peripheral devices) used in telecommunication centres, data-centres and customer premises. + +**3.1.3 load shifting** [b-IADC]: Moving an entire load from a peak time to an off-peak time. + +**3.1.4 nano grid, micro grid** [b-ITU-T L.1205]: A local area grid connecting some buildings together at relatively short distances. It can be in AC or DC. In general, a nano grid is lower than 100 kW and a micro grid can be of higher power. + +**3.1.5 renewable energy** [b-ITU-T L.1205]: Mainly non-fossil fuel converted into electricity (e.g., solar energy, wind, water flow, biomass) which can be obtained from natural resources that can be constantly replenished. + +**3.1.6 smart grid** [b-EU mandate]: A Smart Grid is an electricity network that can cost efficiently integrate the behaviour and actions of all users connected to it – generators, consumers and those that do both – in order to ensure economically efficient, sustainable power system with low losses and high levels of quality and security of supply and safety. + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 back-up energy storage**: Energy storage system able to feed electricity to equipment of an information and communication technology or telecom site in case of unavailability or insufficiency of power source (electric grid or local source) to match the load demand. + +**3.2.2 demand response**: Utility demand to final consumers (households or businesses) providing response in manual or automatic mode, giving flexibility to the electrical system by voluntarily changing the consumer's electrical consumption in reaction to price signals or to specific requests which lead to lower prices for consumers and for utility by avoiding grid over-load and decreasing the need of high-cost power generation often using fossil energy and emitting carbon emission. as defined in [b-eurelectric]. + +**3.2.3 energy storage**: Action or means to store energy for future use. + +**3.2.4 -48 VDC**: -48 Volt Direct Current voltage range at the power interface of ICT equipment, based on [ETSI EN 300 132-2]. + +**3.2.5 lithium-based battery**: Battery that uses lithium electrodes. + +**3.2.6 nickel-based battery**: Battery that uses nickel electrodes. + +**3.2.7 peak shaving**: Technique used to shift a portion of an electrical load at a peak time of day to a non-peak time, thus helping to meet peak demands through the use of alternate power sources such as gas supplies or energy storage as defined in [b-peak shaving]. + +**3.2.8 interface P**: Up to 400 VDC Power feeding interface, based on [ITU-T L.1200]. + +**3.2.9 self-consumption**: Consumption by an electricity consumer of its own energy production. + +**3.2.10 up to 400 VDC:** Up to 400 Volt Direct Current voltage range at the power interface of ICT equipment (equivalent to voltage range defined in [b-ETSI EN 300 132-3-1], as described in [ITU-T L.1200]). + +## **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|--------|------------------------------------------| +| AC | Alternating Current | +| AGM | Absorbent Glass Material | +| BMS | Balancing Monitoring System | +| CAES | Compressed Air Energy Storage | +| CAPEX | Capital Expenditure | +| CO | Central Office | +| CPE | Customer Premises Equipment | +| DC | Direct Current | +| DoD | Depth of Discharge | +| EU | European Union | +| FTTCab | Fibre To The Cabinet | +| ICT | Information and Communication Technology | +| IoT | Internet of Things | +| LV | Low Voltage | +| M2M | Machine-to-Machine | +| MDF | Main Distribution Frame | +| NGA | Next-Generation Access | +| NiCd | Nickel-Cadmium | +| NiMH | Nickel-Metal Hydride | +| NiZn | Nickel-Zinc | +| PHES | Pumped Hydroelectric Energy Storage | +| PSH | Pumped-Storage Hydroelectricity | +| PSOC | Partial State of Charge | +| PSTN | Public Switched Telephone Network | +| SMES | Superconducting Magnetic Energy Storage | +| TE | Telecom Equipment | +| TCO | Total Cost of Ownership | + +# **5 Conventions** + +### **5.1 A (interface)** + +[ETSI EN 300 132-2]: ICT equipment –48 VDC power interface. + +### 5.2 A3 (interface) + +[b-EN 300 132-3-1]: ICT/telecom equipment (TE) up to 400 VDC power interface in ETSI. + +# 6 General introduction of the need for electrical energy storage + +This clause explains various use cases for stationary batteries in ICT applications. + +### 6.1 Short disturbance and dips filtering + +A short autonomy can be added to cover brief electrical supply interruptions, disturbances or dips, requiring high-power discharge rate energy storage. In general, it is composed of batteries or supercapacitors. + +The rationale of this requirement for access networks on good electric grids is provided in Appendix III. + +NOTE – Batteries for this use case can be based on high-power lithium-ion or with nickel-metal hydride (NiMH) or nickel-zinc (NiZn) technology. + +### 6.2 Increased reliability by adding autonomy to cover prolonged grid outages + +The rapid development of telecom networks compared to that of grid development in countries equipped with low-reliability infrastructure or poor quality grids is driving the need to install more batteries to cover frequent and/or prolonged grid outages. + +Sites providing good quality utility grid supply with minimal outages could be established by using low-cost, long-running autonomous rechargeable electric energy storage as an alternative to engine generators or fuel cells. + +NOTE – Compared to legacy lead-acid batteries, a better total cost of ownership (TCO) could be obtained with new high-temperature, pure lead-acid or lead-carbon or lithium-ion batteries, both with some thermal management. For very low cost or high capacity battery solutions, in the near future, flow batteries with large ionic salt tanks, low-power sodium salt/carbon-manganese stack solutions or zinc-air may be competitive. Other metal-air battery solutions need further development and as such are assigned for potential future use. + +### 6.3 Self-consumption of renewable energy increased by storage for on-grid and off-grid systems + +Energy transition toward using less fossil fuels (oil, gas, coal, rare radioactive material) and producing less greenhouse gas (GHG) is promoting the use of more renewable energy solutions that are directly associated with energy storage. This storage should be obtained at an affordable cost and without loss of performance when compared to existing solutions. The use of batteries allows for storing the excess renewable energy produced during high-production periods (e.g., daylight photovoltaic production stored for night use). In this way, energy storage and the use of renewable sources are strongly linked together. + +This evolution toward renewable energy with energy storage is present on existing grids and in developing off-grid telecom networks. + +The relationship between renewable sources and energy storage is independent of the size of the site (small access sites, buildings). + +There are many parameters and considerations (e.g., temperature range, power management, capacity, cycling lifetime, environmental considerations and cost) that will impact the choice of technology. + +### 6.4 Smart grid services with energy storage functionality and possible reliability increase + +Energy transition is introducing demand-response regulation, where a user can contribute to the optimization of electricity generation and power grid transmission capacities. + +The first service that can involve a battery is the power peak shaving associated with relatively short power load shifting, for example, to recharge the battery after the demand peak. + +This approach is also aiming at a controllable situation where energy usage can be shifted to times of renewable energy peak production, i.e., for solar energy at mid-day. It is not clear to what extent this control is applicable to telecom site usage. + +A complementary service is the fast support of the grid in power and frequency, by using a grid-tied inverter, where excess of renewable energy production can be injected back into the local utility grid. + +The inclusion of energy storage at a telecom site allows storing of renewable energy produced on site, and also allows for storage of energy bought from the utility grid during low cost times that can, depending on site usage, be sold back to the utility grid with a profit. + +The use of renewable energy with local site storage can form part of the local nanogrid around the telecom site, e.g., for user service resilience. The telecom site would host the batteries for the nanogrid. The additional batteries may also reduce the unavailability for critical sites by properly managing priorities of supply which is crucial to make this approach usable. + +For this type of telecom site use case, there are many considerations that could influence the technical, environmental and economic choice of a usable end solution [b-Soogreen]. + +### **6.5 Machine-to-machine and Internet of Things devices power supply** + +A part of the stationary machine-to-machine (M2M) and Internet of Things (IoT) device is not connected to the public alternating current (AC) grid or local direct current (DC) power network, and consumes too much to use primary batteries. In this case, a standalone energy solution (e.g., solar cells) associated with supercapacitors or rechargeable batteries, generally lithium-ion or nickel-based type, can be used. + +The main parameters for the selection of these energy storages are high cycling at defined temperature, high efficiency and low self-discharge, energy density, high reliability and defined lifetime, low cost, low impact on environment in operation and end of life to avoid difficult management. + +### **6.6 Voltage interface of energy storage solutions** + +Energy storage solutions used in ICT DC installations, considered in clause 7, shall have a voltage range adapted to feed the power interface at the input of stationary ICT equipment compliant with interface A (–48 V) [ETSI EN 300 132-2] or interface A3 (up to 400 VDC) [ITU-T L.1200], or input for stationary CPE defined in [ITU-T L.1001] e.g., 12 V. + +## **7 Evolution of energy storage** + +Energy storage is covered by many different technologies using various disciplines in their development to achieve best performance to suit their end applications, see Figure 1. This figure gives a rough idea of the range of performances. + +Not all energy storage technologies are relevant for the telecom/ICT sector. In this Recommendation, the focus is on electrical storage technologies of power lower than 10 MW. + +NOTE – The majority of technologies detailed in Figure 1 are scalable to some extent. However, the pumped energy storage solution is better suited in terms of energy scaling/cost/ infrastructure for utility energy, and support to any ICT site would be indirect through the electricity grid. This is the same for magnetic storage having very high capital expenditure (CAPEX) which is more suited to power grid utility applications. + +![Figure 1: Major electricity storage technologies situation. A graph plotting Discharge time (y-axis, log scale from 1 sec to 1 day) against Discharge power (x-axis, log scale from 1 kW to 1 GW). Technologies shown include Batteries for REN sites and smart grid, CAES, PHES, Back-up batteries or traction batteries, Flywheel, Supercapacitors, and SMES.](7c1f9e78e0f033d391b687f1652f6e47_img.jpg) + +Major electricity storage technologies situation + +Discharge time + +1 day + +1 hour + +1 min + +1 sec + +1 kW + +1 MW + +1 GW + +Discharge power + +L.1220(17)\_F01 + +Figure 1: Major electricity storage technologies situation. A graph plotting Discharge time (y-axis, log scale from 1 sec to 1 day) against Discharge power (x-axis, log scale from 1 kW to 1 GW). Technologies shown include Batteries for REN sites and smart grid, CAES, PHES, Back-up batteries or traction batteries, Flywheel, Supercapacitors, and SMES. + +NOTE – Figure based on [b-ESA] and [b-ENEA]. + +**Figure 1 – General overview of energy storage systems** + +Figure 1 shows an approximate representation of each storage type's technological characteristics. Some types, especially "batteries", encompass many technologies. + +Figure 2 shows the general classification of electric storage by intermediate stored energy (e.g., mechanical, electro-chemical). + +| INTERMEDIATE ENERGY STORAGE
in electrical storage systems rechargeable from electricity | | | | | +|--------------------------------------------------------------------------------------------|--------------------------------------|---------------------------------------------------------------------------------------|-------------------------------------|-------------------------------------------------| +| (1) large scale > 80% efficiency | | (2) medium scale > 50% efficiency | | (3) short term | +| (3) short term | | (4) energy pulse | | | +| Mechanical storage | Electrostatic and EM storage | Chemical fuel (from electro-reduction) | Reversible electro-chemical systems | Heat storage | +| PEHS (1) | Capacitor (4, 3 with supercapacitor) | Gas fuels H 2 , other derived from H 2 , ... with fuel cell (2) | Rechargeable batteries (2) | Sensible heat with thermoelectric generator (2) | +| CAES (1 and 2) | SMES (4) | Solid fuel metal in regenerative battery (2) | Flow battery (2) | Latent heat with heat turbine (3) | +| Flywheel (3) | | Liquid fuel flow battery or reversible fuel cell (2) | | Adiabatic CAES (1 and 2) | + +L.1220(17)\_F02 + +NOTE – Figure based on [b-IEC WPstorage] presented in [b-ETSI EE 2015-storage solutions] + +**Figure 2 – General electrical energy storage classification** + +Table 1 provides an example of general electro-chemical energy storage classification. + +**Table 1 – Reversible battery systems** + +| Naming | Internal energy storage | External energy storage (liquid tanks) Flow battery (REDOX) | Hot liquid metal battery | Metal-air or other gas battery | +|-----------------------|---------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------|------------------------------------------|---------------------------------------| +| Lead-acid | Flooded, AGM, gel | | | | +| Alkaline nickel based | NiFe, NiCd, NiMH, NiZn, NiNi, ... | | | Ni-H 2 | +| Lithium based | Lot of Chemistry with Co, Fe, Ni, Mn, Ti, Sulfur, O, P, S, Si, ... and other additive Y, ...
Li-Polymer Li-metal | | | Li-air | +| Sodium based | Na-ion Na 2 SO 4 , Mn | | NaS, NaNiCl 2 | | +| Zn based | ZnMnO 2 | Hybrid ZnBr | | Zn-air | +| Other (Mg, K, Al...) | Mg-ion, K-ion, Al-ion, ... | Vanadium Redox, SBr, ... | Gravitic separation of liquid electrodes | K-air, Mg-Air, Al-air | + +Additional details on various battery technologies can be found in Appendix II. + +## **8 Selection method of energy storage for ICT stationary use** + +This clause presents a method for a multi-criteria selection of energy storage technology and product solutions adapted to a use case for which evaluation and tests are required. + +### **8.1 Selection method based on general criteria and complementary tests** + +In general, a methodical approach should be defined to preselect adapted technologies and products. + +In this respect, a method is used to define a use case with the corresponding requirements and match these requirements with the energy storage technology and product characteristics. + +Once completed, if existing standards, manufacturer test results, and environmental data (e.g., life-cycle analysis (LCA)) are not sufficient for the preselected products, any further relevant testing and analysis can be defined to complement the selection. + +The proposed method will apply to all energy storage technologies and is described by the flow chart in Figure 3. + +![Flow chart of energy storage preselection and test method. The process starts with 'Initial use case' leading to 'Preselection of techno adapted to requirements'. If 'No', it goes to 'Adapt requirements or use case' and loops back. If 'Yes', it goes to 'IEC standards and green + LCA sufficient?'. If 'Yes', it goes to 'Product Ok for next step (market, roll out, etc.)'. If 'Not sufficient (need test complement)', it goes to 'Short tests result OK (voltage, current, charge cells balancing, abuse, LCA) Sufficient?'. If 'No', it goes to 'Improve product or use case' and loops back. If 'Yes', it goes to 'Product Ok for next step (market, roll out, etc.)'. If 'Not sufficient', it goes to 'Long tests result Ok? (float life, cycling, T...)'. If 'No', it goes to 'Bad test results' and loops back to 'Adapt requirements or use case'. If 'Yes', it goes to 'Product Ok for next step (market, roll out, etc.)'.](fa859e4e468bfb2710a94527f2c504af_img.jpg) + +``` + +graph TD + A[Initial use case] --> B{Preselection of techno adapted to requirements} + B -- No --> C[Adapt requirements or use case] + C --> B + B -- Yes --> D{IEC standards and green + LCA sufficient?} + D -- Yes --> G[Product Ok for next step (market, roll out, etc.)] + D -- "Not sufficient (need test complement)" --> E{Short tests result OK (voltage, current, charge cells balancing, abuse, LCA) Sufficient?} + E -- No --> F[Improve product or use case] + F --> B + E -- Yes --> G + E -- "Not sufficient" --> H{Long tests result Ok? (float life, cycling, T...)} + H -- No --> I[Bad test results] + I --> C + H -- Yes --> G + +``` + +L.1220(17)\_F03 + +Flow chart of energy storage preselection and test method. The process starts with 'Initial use case' leading to 'Preselection of techno adapted to requirements'. If 'No', it goes to 'Adapt requirements or use case' and loops back. If 'Yes', it goes to 'IEC standards and green + LCA sufficient?'. If 'Yes', it goes to 'Product Ok for next step (market, roll out, etc.)'. If 'Not sufficient (need test complement)', it goes to 'Short tests result OK (voltage, current, charge cells balancing, abuse, LCA) Sufficient?'. If 'No', it goes to 'Improve product or use case' and loops back. If 'Yes', it goes to 'Product Ok for next step (market, roll out, etc.)'. If 'Not sufficient', it goes to 'Long tests result Ok? (float life, cycling, T...)'. If 'No', it goes to 'Bad test results' and loops back to 'Adapt requirements or use case'. If 'Yes', it goes to 'Product Ok for next step (market, roll out, etc.)'. + +**Figure 3 – Flow chart of energy storage preselection and test method** + +The following is a list of suggested application criteria for energy storage selection: + +- Energy storage family type: battery or supercapacitors. +- Technology types and their main properties. +- Adaptation to system requirement: + - functional availability (autonomy); + - reliability, tolerance to default or abuse; + - electrical parameters: voltage, voltage range, capacity, EMC; + - environment (e.g., temperature, vibration); + - maintenance; + - environmental aspects, eco-design and recycling; + - physical size and weight; + - national rules and regulations; + - cost. + +Appendix II provides examples of a multi-criteria approach to assist in the selection of battery/supercapacitor storage type as compared to other energy storage types. It is completed with an additional classification of the different battery technologies given the defined requirements. + +### 8.2 Detailed description of the main parameters of energy storage technology + +The main parameters to consider when selecting an adapted technology of energy storage are the following: + +- **temperature range:** Extreme operational temperatures dictate the technical choice for reliable and safe operation. At worst, a combination of conditions can be destructive to some technologies, e.g., at very low temperature, lead-acid can freeze when discharged below a + +defined depth of discharge (DOD) limit, or at too high a temperature some lithium technology will not survive. + +- **charge/discharge time:** Often referred to as power rate, defined as the ratio of energy storage capacity over charge/discharge time. For example, a rate of $C_3/3$ represents the charge or discharge current, for a three-hour capacity. +- **partial state of charge (PSOC):** This indicates the use of the technology that is expected, for example, when the lifetime of the storage solution is not affected by staying in a PSOC without immediate recharge. This is critical for intermittent renewable energy systems where the battery can stay in a PSOC for weeks. +- **safety and sensibility level:** Safety is an essential requirement for energy storage to avoid dangerous uncontrolled conditions. For example, lithium-ion technologies require a very strict control of cell voltage and temperature to ensure a safe and reliable operation. Absorbent glass material (AGM): Lead-acid technology is sensitive to thermal runaway and can release hydrogen gas when overcharged, thus requiring strict venting rules. +- **weight and power density:** This can be a critical requirement relevant to battery storage or site installation and indicates if reinforcement requirements are needed for the floor or roof where the battery is located. This is particularly relevant in the case of roof-top or top-floor installations of mobile base stations. +- **volume and volumetric energy:** The energy density of a battery is the capacity of the battery divided by either the weight of the battery (which gives the gravimetric energy density in Wh/kg) or by the volume (which gives a volumetric energy density in Wh/dm3 (or Wh/litre)) A battery with a higher energy density will be lighter than a similar capacity battery with a lower energy density. + +NOTE 1 – Weight and volume are not obvious parameters to assess at battery level as some technologies are very good at cell level, for example, hot sodium but is penalized by thermal insulation material. + +- **efficiency:** This has several definitions such as full-capacity efficiency or step efficiency at different states of charge. There is Coulombic efficiency in electrical charge unit or an energy efficiency in energy unit. + +NOTE 2 – Efficiency is an important parameter for cycling application as the losses corresponds to energy loss and dissipated heat that can affect the energy storage location and the support required or the impact on the other equipment in the same location. + +- **self-discharge and temperature dependency:** Internal chemical reactions or other leakage phenomenon (e.g., electrical, thermal, water evaporation) reduce the stored charge of the energy storage device without any connection between the poles (external and also internal electrodes of batteries or supercapacitors). Temperature has a direct effect on this parameter for most storage technologies. For example, at low temperatures a battery increases internal resistance, thus reducing the battery's capacity. Whereas, at high temperatures battery performance will improve, but battery life will be shortened. + +NOTE 3 – Self-discharge is an important parameter in charge retention of batteries before being used. At high temperature, some storage technologies can be fully self-discharged in a matter of weeks and this can be irreversible or require a costly restart process. In addition, low self-discharge corresponds to energy saving in the long run. + +- **cost constraints:** Cost comparisons could be on relative CAPEX in cost per stored kWh of energy storage. It can also be expressed in TCO in cost per cycled kWh over the lifetime of the storage. This comparison is inverted when considering CAPEX and TCO comparison. Some storage technologies can have a much higher CAPEX, but offer a better TCO in the long run due to the longer lifetime of the energy storage. + +- **lifetime:** Lifetime is characterized by a set of parameters including: the number of cycles at different defined DODs, storage time before commissioning, operational lifetime. All of these are temperature dependent and conform to different degradation mechanisms. + +## 9 Test methods + +### 9.1 General introduction + +There is a need for simple, effective and sufficiently precise test methods that provide results in a reasonable time-frame and complement methods described in existing standards, if these standards do not cover the full range of the test. Examples of these standards are [b-IEC 60896-X] for lead-acid batteries, [b-IEC 62619] and [b-IEC 62620] for other batteries. + +Part 1 of this series of Recommendations focuses on generic tests for all technologies, while tests for specific technologies are covered in the other parts. + +In accordance with the parameters of energy storage technologies listed in clause 8.2, the test severity given in Table 2 helps to check existing standards test results from manufacturers and to define the requirements for additional use tests defined as: abuse, extreme, normal hard, normal soft and longest life. + +**Table 2 – Test severity depending on use case and corresponding defined requirements** + +| abuse | externe | normal hard | normal soft | longest life | +|----------------------------------------|---------------------------------------|----------------------------|--------------------------------------------|--------------------------------------------| +| too long storage before use | max permitted storage time before use | mid storage before use | short storage before use | short storage before use | +| over voltage in charge | full discharge | deep discharge (e.g., 80%) | moderate cycling number and depth | few small cycling | +| under voltage in discharge and storage | fast cycling with no rest time | fast recharge | adapted charge/discharge state and voltage | optimal charge/discharge state and voltage | +| over charge | high charge voltage | high cycling | medium temperature | state optimal temperature | +| over/under charge/discharge power | externe temperature | high low temperature | regeneration cycle? | regeneration cycle? | +| externe temperature | persistent cell unbalance | regeneration cycle? | | | +| | recharge level (high or partial) | | | | + +L.1220(17)\_Table01 + +### 9.2 Test flowchart + +The detailed test flowchart shown in Figure 4 should be followed in order to obtain repetitive results, for observation and interpretation to determine and to define further tests or product improvements or changes. + +![Flow chart of testing of energy storage and cell technology. The process starts with 'NEW storage cell and/or storage system to test'. It branches into 'Individual cell?' and 'Storage system?'. Both lead to a common set of test categories: 'Normal tests', 'Stress tests', 'Abuse tests', 'Shelf tests', and 'regener action'. For 'Storage system?', these are further detailed with 'Charge balancing', 'ICT interface voltage limits?', 'Control monitoring', 'Commissioning', and 'Storage module paralleling'. All test categories lead to 'Next step of test'. From 'Next step of test', there are three paths: 'End of defined normal use?' (green hexagon), 'End of extended life?' (yellow hexagon), and 'END by exceeding safety limits' (red oval). A 'Loop' arrow connects 'End of defined normal use?' back to 'Next step of test'. A dashed arrow labeled 'Progressing ageing?' connects 'End of defined normal use?' to 'End of extended life?'. A text box 'Storage cell tests ok possible tests on storage system' is positioned above the test categories.](9c6461e1e94afae4dec455e69a2ce152_img.jpg) + +Flow chart of testing of energy storage and cell technology. The process starts with 'NEW storage cell and/or storage system to test'. It branches into 'Individual cell?' and 'Storage system?'. Both lead to a common set of test categories: 'Normal tests', 'Stress tests', 'Abuse tests', 'Shelf tests', and 'regener action'. For 'Storage system?', these are further detailed with 'Charge balancing', 'ICT interface voltage limits?', 'Control monitoring', 'Commissioning', and 'Storage module paralleling'. All test categories lead to 'Next step of test'. From 'Next step of test', there are three paths: 'End of defined normal use?' (green hexagon), 'End of extended life?' (yellow hexagon), and 'END by exceeding safety limits' (red oval). A 'Loop' arrow connects 'End of defined normal use?' back to 'Next step of test'. A dashed arrow labeled 'Progressing ageing?' connects 'End of defined normal use?' to 'End of extended life?'. A text box 'Storage cell tests ok possible tests on storage system' is positioned above the test categories. + +L.1220(17)\_F04 + +**Figure 4 – Flow chart of testing of energy storage and cell technology** + +The following explanation provides understanding to the process defined in Figure 4. + +- **normal tests:** Cycling test at different charge/discharge current rates, back-up operation test, combined operation tests made at different temperatures. +- **stress or abuse tests:** Additional stress over normal test parameter values (e.g., voltage, current, temperature, depth of discharge, cell charge or voltage unbalance). +- **shelf tests:** These tests correspond to transport and storage time, possibly at high temperatures, between the manufacturing site and the installation site. + +#### Test acceleration + +The duration of tests can be variable, depending on the nature and condition of the tests. For example, testing fast charge/discharge cycles may take many months (e.g., 1200 cycles of 1 h charge/1 h discharge at 100% DOD, i.e., 2400 h, takes about 3 months), while testing back-up lifetime at 25°C can last 10 years. It is clear that there is a need to accelerate tests by running them in parallel or by activating ageing factors provided the test remains representative of real behaviour in normal use conditions. + +- **parallel tests:** Tests could be run in parallel on different cells or blocks to save time relative to serial tests. +- **test reliability:** For each test, more reliable results should be obtained by conducting tests on several cells or blocks. +- **severe tests:** Extreme, stress, and hard tests could be run before running soft tests, from shorter to longer, depending on requirement levels. + +It should be taken into consideration that extreme and stress tests might be destructive. + +#### Balancing monitoring system (BMS) tests + +- **balancing information:** The type of balancing should be provided (in charge, in discharge, both, dissipative or not), and also balancing response time, e.g., giving balancing current in % of cell capacity. + +- **balancing check-up:** Is initial start possible after storage of several months? Is full charge obtained and in what time? When cells are accessible, balancing with discharged or poor cells. +- **monitoring functionality:** Battery status reporting information, e.g., voltage, current, temperature, alarms. +- **other functionality:** Commissioning, remote access, paralleling, etc. + +### 9.3 Additional considerations + +#### 9.3.1 Physical tests + +The evolution of weight (e.g., due to loss of water for non- lithium batteries) and the mechanical stability of casing are very important parameters to monitor for energy storage devices, in particular during use in cyclic, extreme temperature or temperature gradients. + +#### 9.3.2 Cycling tests and complexity of voltage settings + +Testing should be closer to real life scenarios using active loads. Evaluation of the capacity of the battery or capacitor should also be controlled in Ah or Coulomb as it allows for the evaluation of efficiency, which is not only an important parameter for energy conservation but also as an indicator of ageing. + +The charge profile should have to be defined in detail, considering simple evaluation and real use cases, i.e., constant current, constant voltage, among other criteria such as variable intermittent energy charge and variable loads. + +The discharge profile is also a critical parameter as the energy storage voltage range in charge and discharge shall be adapted to the voltage range defined at telecom power interface (in [ETSI EN 300 132-2] for –48 V equipment or in [ITU-T L.1200] for up to 400 VDC equipment). As a consequence, the storage capacity shall be defined at minimum in this voltage range unless voltage converter is used between the storage and the telecom load. + +In general, when the battery is used without a converter, a narrow range is defined to take into account the voltage loss in cables, for example, 2 V in the case of –48 V, which means that minimum discharge voltage is, in practice, not defined as –40.5 V, but rather as –43 V. + +As a consequence, the storage capacity shall be defined at minimum inside this voltage range unless it is planned to use a voltage converter between the storage and the telecom load. + +## Appendix I + +## Energy storage (battery, supercapacitor) world-market evolution + +(This appendix does not form an integral part of this Recommendation.) + +The world battery market evolution, see Figure I.1, shows strong development in storage capacity and new battery technologies. + +![Figure I.1: World battery market evolution and share estimation between lead-acid and lithium-ion technology for Telecom network and server UPS. The figure contains two charts. The left chart shows the world battery market evolution from 1990 to 2013 in Billion US$ by application. The right chart shows the share estimation between lead-acid and lithium-ion technology for Telecom network and server UPS from 2012 to 2020 in Million US$.](79cb7fa0e9c78ec5cd0b0de977824f8d_img.jpg) + +**Left Chart: World battery market evolution (1990-2013)** + +| Year | SLI (Démarrage) | PORTABLE | POWER TOOLS | E-BIKES | INDUSTRIAL | AUTOMOTIVE-VE | OTHERS | Part Telecom + UPS = 5,25 B\$ | +|------|-----------------|----------|-------------|---------|------------|---------------|--------|-------------------------------| +| 1990 | ~12 | ~1 | ~1 | ~1 | ~2 | ~1 | ~1 | - | +| 2000 | ~13 | ~8 | ~1 | ~1 | ~3 | ~1 | ~1 | - | +| 2005 | ~15 | ~10 | ~1 | ~1 | ~4 | ~1 | ~1 | - | +| 2010 | ~16 | ~12 | ~1 | ~1 | ~10 | ~1 | ~1 | - | +| 2013 | ~20 | ~15 | ~1 | ~1 | ~15 | ~1 | ~1 | ~5,25 | + +**Right Chart: Share estimation between lead-acid and lithium-ion technology for Telecom network and server UPS (2012-2020)** + +| Year | Lead Acid | LIB | ASP 2012 (\$/kWh) | ASP 2020 (\$/kWh) | +|------|-----------|------|-------------------|-------------------| +| 2012 | ~2800 | ~200 | 600 | 400 | +| 2013 | ~2800 | ~200 | 600 | 400 | +| 2014 | ~2800 | ~200 | 600 | 400 | +| 2015 | ~2800 | ~300 | 600 | 400 | +| 2016 | ~2800 | ~400 | 600 | 400 | +| 2017 | ~2800 | ~500 | 600 | 400 | +| 2018 | ~2800 | ~600 | 600 | 400 | +| 2019 | ~2800 | ~700 | 600 | 400 | +| 2020 | ~2800 | ~800 | 400 | 185 | + +Figure I.1: World battery market evolution and share estimation between lead-acid and lithium-ion technology for Telecom network and server UPS. The figure contains two charts. The left chart shows the world battery market evolution from 1990 to 2013 in Billion US\$ by application. The right chart shows the share estimation between lead-acid and lithium-ion technology for Telecom network and server UPS from 2012 to 2020 in Million US\$. + +**Figure I.1 – World battery market evolution and share estimation between lead-acid and lithium-ion technology for Telecom network and server UPS, based on Orange and Avicenne approach [b-Avicenne]** + +## Appendix II Multi-criteria approach to choosing energy storage + +(This appendix does not form an integral part of this Recommendation.) + +This appendix gives examples of parametric multi-criteria approaches to choosing a physical type of energy storage for defined requirements of a use case. + +These approaches will help refine the choice of an energy storage technology. For batteries, it will help in the selection of chemistry, e.g., selecting a battery of lithium-ion technology with lithium iron phosphate chemistry. + +Figure II.1 compares energy storage technologies considering different parameters, some of them roughly corresponding to service, power back-up or energy reserve, such as reserve time, power, cycling ability, lifetime, etc., or even cost versus performance. + +Supercapacitors and battery technologies offer different power densities and have different expected lifetime temperature parameters. + +The storage parameters give a general overview, and do not correspond to storage use for data centres, telecom centres or distributed telecom equipment. + +For example, lead-acid batteries are not an obsolete storage technology, especially when large energy capacities are required. Emergent technologies are particularly interesting for short power outages (large energy requirement for a short period of time) and if sited in harsh environments with high temperatures and uncontrolled PSOC. + +![Figure II.1: Example of general comparison of energy storage service in terms of discharge time and power, based on [b-ENEA]. The graph plots Energy autonomy (discharge time) on the y-axis against Power on the x-axis for various energy storage technologies.](c7c1a2a04d07232ca372d3ea08fb19fc_img.jpg) + +The graph shows the relationship between Energy autonomy (y-axis) and Power (x-axis) for various energy storage technologies. The y-axis is logarithmic, ranging from μs, ms to 10 days. The x-axis is also logarithmic, ranging from 1 kW to 1 GW. A horizontal line at 1 h on the y-axis and a vertical line at 1 MW on the x-axis intersect at a point labeled '1'. Two vertical double-headed arrows on the right indicate 'High ratio power/energy' for technologies above the intersection and 'High ratio power/energy' for technologies below it. + +| Energy Storage Technology | Power Range (kW to GW) | Energy Autonomy Range (μs, ms to 10 days) | +|-----------------------------------|------------------------|-------------------------------------------| +| Solar lead acid | 1 kW to 100 kW | 1 day to 10 days | +| Lithium or NiMH, NiZn | 1 kW to 100 kW | 10 h to 1 day | +| Telecom lead acid | 1 kW to 100 kW | 1 h to 10 h | +| UPS or grid ESS lead acid or NiCd | 1 kW to 100 kW | min to 1 h | +| Flywheel | 10 kW to 100 kW | sec to min | +| Supercapacitor | 1 kW to 10 MW | μs, ms to sec | +| Power capacitor, SMES | 1 kW to 10 MW | μs, ms to sec | +| Thermal ES | 100 kW to 100 MW | 10 h to 1 day | +| CAES | 100 MW to 1 GW | 1 h to 1 day | +| PHES | 100 MW to 1 GW | 1 h to 1 day | + +Figure II.1: Example of general comparison of energy storage service in terms of discharge time and power, based on [b-ENEA]. The graph plots Energy autonomy (discharge time) on the y-axis against Power on the x-axis for various energy storage technologies. + +L.1220(17)\_FII.1 + +**Figure II.1 – Example of general comparison of energy storage service in terms of discharge time and power, based on [b-ENEA]** + +Table II.1 gives a general comparison of battery and other energy storage technologies focused on the use for ICT equipment wheel. + +**Table II.1 – General comparison of energy storage solutions (mainly electrochemical) from [b-ETSI EE 2015-storage solutions]** + +![A vertical blue arrow on the left side of the table, pointing upwards, labeled 'Maturity'.](ad6c36347e94fca1b0d1be8b0035401e_img.jpg) + +| Techno | ++ | + | - | -- | +|--------------------|----------------------------------------------|-------------------------------|-----------------------------|---------------------| +| Pb | Cost | Charge management | Green - Temperature | | +| NiFe | | Life expectancy | Efficiency | water consumption | +| NiCd | Deep discharge cycle-life | Low Temp Perf. | Cost (CAPEX) | | +| NiMH | Safety | Cycling | Charge Management | Cost (CAPEX) | +| Li Ion | Cycling + PSOC | Energy density | Field experience | Cost (CAPEX) backup | +| NaS | Cycling | No ambient temperature effect | Safety issues | Cost (CAPEX) | +| NaNiCl2 | Cycling | No ambient temperature effect | Efficiency | Thermal management | +| NiZn | Green + Cost | Cycling | Field experience | | +| RedOx | No self discharge + energy/power independent | No ambient temperature effect | Efficiency - Energy density | | +| Metal Air | Energy density | Green | Charge management | Cycling | +| H2 + Electrolyseur | High energy storage | Green + Abundant | Efficiency safety | Cost (CAPEX) | +| Fly wheel | Power + Cycling | Green + Abundant | Safety | Energy Performance | + +1 - Batteries Evolution 2013 - APR 2013 + +L.1220(17)\_TII.1 + +NOTE – For each technology, four criteria are evaluated from "++", the best, to " -- ", the worst (or in colour scale: green, white, yellow, orange, red). + +Tables II.2, II.3 and II.4 give a general comparison of batteries. + +**Table II.2 – Example of general comparison of battery technologies based on [b-battery BU-107] and [b- battery BU-205]** + +| Specification | Lead-acid | NiCd, NiMH, NiZn | Li-ion (many different technologies) | +|-----------------------------------------|---------------------------------------------------------------------------------|--------------------------------------------------------------------------|------------------------------------------------------------------------------------------| +| Available since | late 1800s | NiCd and NiZn early 1900s, NiMH 1990 | 1990 | +| Specific energy Wh/kg | 30/50 | 45/120 | 60-250 | +| Specific power kW/kg | < 1 | < 1 | < 3 | +| Cell voltage | 2 | 1.2 to 1.6 V | 2.3 to 4 V | +| Cycle life
(at 80% capacity) | 300 to 1500 | 300 to 2000 | | +| Charge voltage limit | 2.3 to 2.6 V | 1.5 to 2 V | 3 to 4.2 V | +| Overcharge tolerance | high | moderate | very low to low | +| Temperature | –20 to 60°C | –40 to +60°C | 0 to 60°C
heater below | +| Safety requirements | thermally stable,
remove H 2 from charge | thermally stable | mandatory protection of
each cell against low- and
high-voltage and
temperature | +| Lifetime | up to 20 years at 20°C
5 to 10 at 40°C
(cells balancing by
overcharge) | up to 20 years weak
(15 at 40°C)
(no or simple cells
balancing) | up to 10-20 years
with complex cell
balancing | +| Energy efficiency
and self-discharge | 80%
2 to 10% | 70 to 85%
5 to 30% | 90 to 95%
3% in electronic | +| Toxicity | high | very high for nickel-
cadmium (NiCd),
low for NiZn | high for organic
electrolyte | +| Relative cost | 1 to 3 | 3 to 7
over cost of rare earths
for NiMH | 5 to 10
costs of chemistry,
electronics and
manufacturing | + +Table II.3 focuses on the diversity of lithium battery technology. Table II.3 relates to technologies used mostly for portable devices. + +**Table II.3 – Example of general comparison of lithium battery technologies** + +| Lithium
battery
chemistry | Safety | Power density | Energy density | Cycles | Costs | +|-------------------------------------|--------|---------------|----------------|--------|--------| +| Iron phosphate
(LFP) | high | high | medium | high | medium | +| Nickel
manganese
cobalt (NMC) | medium | medium | medium | low | low | +| Manganese
oxide (LMO) | medium | medium | medium | low | low | + +**Table II.3 – Example of general comparison of lithium battery technologies** + +| Lithium battery chemistry | Safety | Power density | Energy density | Cycles | Costs | +|---------------------------|--------|---------------|----------------|-----------|--------| +| Titanate (LTO) | high | high | low | very high | medium | +| Cobalt oxide (LCO) | low | low | high | low | low | + +The different shapes of lithium batteries are shown in Figure II.2. + +![Figure II.2 shows three different shapes of lithium batteries: Cylindrical (18650), Prismatic, and Pouch. Below the images is the text 'L.1220(17)_FII.2'.](a8807f349e4e4d1d425fe4148f81741d_img.jpg) + +Figure II.2 shows three different shapes of lithium batteries: Cylindrical (18650), Prismatic, and Pouch. Below the images is the text 'L.1220(17)\_FII.2'. + +**Figure II.2 – Different shapes of lithium batteries** + +Table II.4 relates mostly to electric vehicle applications where energy density vs. safety are major parameters in addition to operating conditions of power, temperature range and lifetime under cost constraints. It appears that the safer technologies are in lower voltage and energy density ranges. + +**Table II.4 – Example of multi-criteria classification of Li-ion battery technologies** + +| Name | LCO | LNO | NCA | NMC | LMO spinel | LFP, LMFP | LTO anode | LIS R&D | Lmeta I R&D | +|---------------------------|--------------------|--------------------|---------------------------------------------------|---------------------------------------------------|--------------------|---------------------|------------------------------------------------|---------|-------------| +| Cathode | LiCoO 2 | LiNiO 2 | LiNi x Co y Al z | LiNi x Mn y Co z | LiMnO 2 | LiFePO 4 | any e.g. LMO 2 | | | +| Anode | Graphite | Graphite | Graphite | Graphite | Graphite | Graphite | Li x Ti y O z | | | +| Mean cell Voltage | 3.6-3.8V | 3.6V | 3.6V | 3.7-4V | 3.8 | 3.3V | 2.4 | 2.1V | 2.7-3V | +| Wh/kg | 100-180 | 150 | 140-200 | 160-200 | 135-220 | 100-130 | 55 | 300-400 | 100-150 | +| Discharge rate | 4C | 1C | 10-20C | 4-20C | 5-15C | 5-20C | 20C | | | +| Safety (- / 0 / +) | - | 0 | 0 | 0 | 0 | ++ | ++ | ? | ? | +| Lifetime (years) | 5-8 | ? | 10-20 | 7-10 | 10-12 | 8-12 | 20 | | | +| Cycles 80% DoD | 1000 | ? | 4000 | 3000 | 2000 | 3000 | 10000 | 100 | 3000 | +| Cost | ++ | + | + | + | + | + | - | ? | - | + +NOTE – The source of this table is an analysis made based on different documents, including [b-Soogreen]. + +## Appendix III + +## Rationale for very short autonomy on good grids obtained by supercapacitor or high-power rechargeable battery + +(This appendix does not form an integral part of this Recommendation.) + +This appendix outlines the rationale for using very short autonomy, mainly in access networks on good grids with few interruptions longer than a few seconds or minutes. + +In many standards, alternative energy solutions have been described with short autonomy for access networks [b-ETSI TR 102 532], [b-EN 302 099]. + +They can refer to grid reports showing improvement in availability in Europe, as shown later, and also in order to reduce the environmental impact of batteries as in [b-RSE report]. + +Statistical data on electrical power supply availability, from the low voltage (LV) public grid (mains) in various European countries, can be a relevant element for TE's power supply protection strategy, in a next-generation access (NGA) network context. In Figures III.1 and III.2, data on public electrical power grid availability, from main European countries, are shown (including medium voltage and LV interruptions – source [b-CEER]. Data changes from country to country, but a general trend of improvement in power grid availability is observed. + +![Line graph titled 'UNPLANNED SAIDI - without exceptional events Average annual time of interruption (minutes)' showing data for 28 European countries from 1999 to 2013. The Y-axis represents the average annual time of interruption in minutes, ranging from 0 to 800. The X-axis represents the years from 1999 to 2013. Most countries show a general downward trend in interruption times over the period, with Malta showing the highest values (peaking near 700 minutes in 2009) and many others showing values below 100 minutes by 2013.](f880daa1cde4b71fcbaff2df81803a65_img.jpg) + +The graph displays the average annual time of unplanned SAIDI (System Average Interruption Frequency Index) for various European countries from 1999 to 2013, excluding exceptional events. The Y-axis is labeled 'Average annual time of interruption (minutes)' and ranges from 0 to 800. The X-axis shows the years from 1999 to 2013. The legend lists 28 countries: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland\*, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Macedonia, Malta\*, The Netherlands, Norway\*, Poland, Portugal, Romania, Slovak Republic, Slovenia\*, Spain, Sweden, Switzerland, and United Kingdom. Malta\* shows a significant peak in 2009, reaching nearly 700 minutes. Most other countries show a general improvement (reduction in interruption time) over the period, with many ending below 100 minutes in 2013. + +Line graph titled 'UNPLANNED SAIDI - without exceptional events Average annual time of interruption (minutes)' showing data for 28 European countries from 1999 to 2013. The Y-axis represents the average annual time of interruption in minutes, ranging from 0 to 800. The X-axis represents the years from 1999 to 2013. Most countries show a general downward trend in interruption times over the period, with Malta showing the highest values (peaking near 700 minutes in 2009) and many others showing values below 100 minutes by 2013. + +Figure III.1 – Data on power grid availability for European countries (unplanned SAIDI) from [b-CEER] + +![Line graph showing the average annual number of long interruptions (SAIFI) for various European countries from 1999 to 2013. The y-axis ranges from 0 to 8. The x-axis shows years from 1999 to 2013. The legend lists 28 countries: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland*, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Macedonia, Malta*, The Netherlands, Norway*, Poland, Portugal, Romania, Slovak Republic, Slovenia*, Spain, Sweden, Switzerland, and United Kingdom. Most countries show a general downward trend in SAIFI over the period, with some notable peaks like Portugal in 2002 and Malta in 2010.](bfb6d182d624680db577069bbc0b2a93_img.jpg) + +**UNPLANNED, SAIFI - without exceptional events** +**Average annual number of long interruptions** + +Line graph showing the average annual number of long interruptions (SAIFI) for various European countries from 1999 to 2013. The y-axis ranges from 0 to 8. The x-axis shows years from 1999 to 2013. The legend lists 28 countries: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland\*, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Macedonia, Malta\*, The Netherlands, Norway\*, Poland, Portugal, Romania, Slovak Republic, Slovenia\*, Spain, Sweden, Switzerland, and United Kingdom. Most countries show a general downward trend in SAIFI over the period, with some notable peaks like Portugal in 2002 and Malta in 2010. + +**Figure III.2 – Data on power grid availability for European countries (unplanned SAIFI) from [b-CEER]** + +Figures III.3, III.4 and III.5 give equivalent information for the Italian electrical LV power grid [b-AEEGSI]. + +![Stacked bar chart showing lost minutes per customer per year for Italy from 1998 to 2014. The y-axis ranges from 0 to 200. The x-axis shows years from 1998 to 2014. The legend indicates two categories: 'Other interruptions not under the responsibility of the distribution system operator' (red) and 'Interruptions under the responsibility of the distribution system operator' (blue). The chart shows a significant decrease in total lost minutes from 1998 to 2007, followed by a slight increase and then a decrease again. The blue portion (under the operator's responsibility) is generally the larger component.](6e5a85131eedf6b98db62877ee64506e_img.jpg) + +**Lost minutes per customer per year** +(Not including defence system's activation, National Transmission Network incidents, and interruptions from thefts) + +| Year | Interruptions under the responsibility of the distribution system operator (blue) | Other interruptions not under the responsibility of the distribution system operator (red) | +|------|-----------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------| +| 1998 | 185 | 0 | +| 1999 | 190 | 0 | +| 2000 | 131 | 56 | +| 2001 | 97 | 52 | +| 2002 | 78 | 37 | +| 2003 | 70 | 35 | +| 2004 | 59 | 32 | +| 2005 | 61 | 19 | +| 2006 | 50 | 11 | +| 2007 | 48 | 10 | +| 2008 | 50 | 33 | +| 2009 | 46 | 24 | +| 2010 | 44 | 25 | +| 2011 | 40 | 22 | +| 2012 | 43 | 53 | +| 2013 | 39 | 26 | +| 2014 | 31 | 17 | + +L.1220(17)\_FIII.3 + +Stacked bar chart showing lost minutes per customer per year for Italy from 1998 to 2014. The y-axis ranges from 0 to 200. The x-axis shows years from 1998 to 2014. The legend indicates two categories: 'Other interruptions not under the responsibility of the distribution system operator' (red) and 'Interruptions under the responsibility of the distribution system operator' (blue). The chart shows a significant decrease in total lost minutes from 1998 to 2007, followed by a slight increase and then a decrease again. The blue portion (under the operator's responsibility) is generally the larger component. + +**Figure III.3 – Data on power grid availability for Italy (unplanned SAIDI) from [b-CEER]** + +![Line graph showing 'Lost minutes per Low Voltage customer per year' for North, Centre, South, and Italy from 1998 to 2014. The y-axis ranges from 0 to 300. The x-axis shows years from 1998 to 2014. Data series: North (green diamonds), Centre (red squares), South (blue triangles), and Italy (grey squares).](2a23751710f7827065d2b99b6df588df_img.jpg) + +| Year | North | Centre | South | Italy | +|------|-------|--------|-------|-------| +| 1998 | 89 | 166 | 257 | 163 | +| 1999 | 82 | 166 | 224 | 147 | +| 2000 | 72 | 133 | 207 | 131 | +| 2001 | 66 | 92 | 144 | 97 | +| 2002 | 54 | 81 | 108 | 78 | +| 2003 | 45 | 68 | 105 | 70 | +| 2004 | 44 | 64 | 78 | 59 | +| 2005 | 37 | 67 | 90 | 61 | +| 2006 | 32 | 51 | 74 | 50 | +| 2007 | 28 | 48 | 78 | 44 | +| 2008 | 36 | 50 | 71 | 48 | +| 2009 | 30 | 41 | 73 | 46 | +| 2010 | 29 | 46 | 63 | 44 | +| 2011 | 25 | 40 | 62 | 40 | +| 2012 | 27 | 43 | 64 | 43 | +| 2013 | 28 | 37 | 55 | 39 | +| 2014 | 28 | 38 | 50 | 37 | + +L.1220(17)\_FIII.4 + +Line graph showing 'Lost minutes per Low Voltage customer per year' for North, Centre, South, and Italy from 1998 to 2014. The y-axis ranges from 0 to 300. The x-axis shows years from 1998 to 2014. Data series: North (green diamonds), Centre (red squares), South (blue triangles), and Italy (grey squares). + +**Figure III.4 – Data on power grid availability for Italy (detail of unplanned SAIDI for north, centre and south Italy) from [b-AEEGSI]** + +![Line graph showing 'Average number of interruptions per customer per year' for North, Centre, South, and Italy from 2004 to 2014. The y-axis ranges from 0 to 10. The x-axis shows years from 2004 to 2014. Data series: North (green diamonds), Centre (red squares), South (blue triangles), and Italy (grey squares).](abc0eb594f9d2c0daa0e60df05f2a666_img.jpg) + +| Year | North | Centre | South | Italy | +|------|-------|--------|-------|-------| +| 2004 | 3.39 | 5.50 | 8.75 | 5.61 | +| 2005 | 2.94 | 5.47 | 8.52 | 5.31 | +| 2006 | 2.77 | 4.77 | 7.64 | 4.79 | +| 2007 | 2.59 | 3.99 | 8.17 | 4.73 | +| 2008 | 2.84 | 3.83 | 7.56 | 4.60 | +| 2009 | 2.53 | 3.41 | 8.26 | 4.61 | +| 2010 | 2.33 | 3.43 | 6.30 | 3.87 | +| 2011 | 2.13 | 2.77 | 5.58 | 3.40 | +| 2012 | 2.13 | 2.88 | 5.33 | 3.34 | +| 2013 | 2.13 | 2.74 | 4.79 | 3.13 | +| 2014 | 2.23 | 2.75 | 4.61 | 3.12 | + +L.1220(17)\_FIII.5 + +Line graph showing 'Average number of interruptions per customer per year' for North, Centre, South, and Italy from 2004 to 2014. The y-axis ranges from 0 to 10. The x-axis shows years from 2004 to 2014. Data series: North (green diamonds), Centre (red squares), South (blue triangles), and Italy (grey squares). + +**Figure III.5 – Data on power grid availability for Italy (unplanned SAIFI for north, centre and south area) from [b-AEEGSI]** + +Figure III.6 shows the comparison of the total unavailability of public switched telephone networks (PSTNs) and of new NGA networks (fibre to the cabinet (FTTCab)) architecture, with or without adoption of mains' micro-interruption coverage – up to 1 s – by supercapacitor adoption), as an example for the Italian network. The total unavailability is, as a basis, primarily related to access network, main distribution frame (MDF) in central office (CO) and network equipment reliability. + +New fibre-based NGA networks give, in general, a higher availability and reliability, with respect to traditional access network technologies. + +In a PSTN scenario, no extra unavailability from public mains is taken into account (since PSTN has coverage of power outage through CO's batteries). In an NGA network scenario, unavailability from public mains and related ICT reboots also has to be taken into account. As shown from the analysis in Figure III.6, the adoption of a power conditioning unit (supercapacitor for 1-second coverage of micro-interruptions of mains) can significantly reduce the total unavailability of NGA networks (with a sensible reduction due to ICT reboots), giving a total level of unavailability lower than traditional PSTN from the CO. + +![Stacked bar chart comparing unavailability of FTTCab equipment with and without super-capacitors against PSTN. The chart shows five categories: Target reduction of public mains unavailability, Unavailability from public mains, Unavailability from equipment reboots, Unavailability from equipment, and Unavailability from access network and MDF. FTTCab with super-cap 1s has the lowest total unavailability at approximately 75%.](20727e57890be6da5692a02d13c0a8ec_img.jpg) + +| Scenario | Unavailability from access network and MDF (%) | Unavailability from equipment (%) | Unavailability from equipment reboots (%) | Unavailability from public mains (%) | Target reduction of public mains unavailability (%) | Total (%) | +|---------------------------------------|------------------------------------------------|-----------------------------------|-------------------------------------------|--------------------------------------|-----------------------------------------------------|-----------| +| FTTCab equipment with super-cap 1s | 25 | 15 | 5 | 15 | 15 | 75 | +| FTTCab equipment without super-cap 1s | 25 | 15 | 45 | 15 | 15 | 115 | +| PSTN | 50 | 45 | 0 | 0 | 0 | 95 | + +Stacked bar chart comparing unavailability of FTTCab equipment with and without super-capacitors against PSTN. The chart shows five categories: Target reduction of public mains unavailability, Unavailability from public mains, Unavailability from equipment reboots, Unavailability from equipment, and Unavailability from access network and MDF. FTTCab with super-cap 1s has the lowest total unavailability at approximately 75%. + +Figure III.6 – Unavailability of new NGA network (FTTCab) vs. classic PSTN + +## Bibliography + +- [b-ITU-T L.1205] Recommendation ITU-T L.1205 (2016), *Interfacing of renewable energy or distributed power sources to up to 400 VDC power feeding systems.* +- [b-ETSI EE 2015-storage solutions] *Energy Storage Solutions Panorama for Telecom Stand-By applications, Campion 3C projects, Third ETSI Workshop on ICT Energy Efficiency and Environmental Sustainability, Sophia Antipolis June 2015.* +[https://docbox.etsi.org/Workshop/2015/201506\\_EEWORKSHOP](https://docbox.etsi.org/Workshop/2015/201506_EEWORKSHOP) +- [b-ETSI EN 300 132-3-1] ETSI EN 300 132-3-1 (2012), *Power supply interface at the input to telecommunication and datacom (ICT) equipment Operated by rectified current source, alternating current source or direct current source up to 400 V, Sub-part 1: Direct current source up to 400 V.* +- [b-ETSI TR 102 532] TR 102 532 V1.1.1 (2009-06) *Environmental Engineering (EE), The use of alternative energy solutions in telecommunications installations.* +- [b-Avicenne] Pillot, C. Avicenne Energy. 2017, *Evolution du marché mondial des batteries rechargeables, Impact sur la demande en Nickel, Cobalt et Lithium.* +[http://www.mineralinfo.fr/sites/default/files/upload/comes\\_presentation-c.\\_pillot\\_fevrier\\_2017\\_pour\\_diffusion.pdf](http://www.mineralinfo.fr/sites/default/files/upload/comes_presentation-c._pillot_fevrier_2017_pour_diffusion.pdf) +- [b-AEEGSI] AEEGSI report 16th May 2015 +([www.autorita.energia.it/allegati/com\\_stampa/15/151116cs.pdf](http://www.autorita.energia.it/allegati/com_stampa/15/151116cs.pdf)) +- [b-battery BU-107] Battery University, *BU-107: Comparison Table of Secondary Batteries.* +[http://batteryuniversity.com/learn/article/secondary\\_batteries](http://batteryuniversity.com/learn/article/secondary_batteries) +- [b-battery BU-205] Battery University, *BU-205: Types of Lithium-ion.* +[http://batteryuniversity.com/learn/article/types\\_of\\_lithium\\_ion](http://batteryuniversity.com/learn/article/types_of_lithium_ion) +- [b-CEER] CEER (Council of European Energy Regulators) – *Benchmarking Report 5.2 on the Continuity of Electricity Supply – Ref: C14-EQS-62-03 (12 February 2015).* +- [b-Elsevier 2016-ESS applications] Mathew A., Meihong W., Elsevier Applied Energy, August 2016. *Energy storage technologies and real life applications – A state of the art review.* +- [b-EN 302 099] ETSI EN 302 099 (2014), *Environmental Engineering (EE), Powering of equipment in access network.* +- [b-ENEA] *Fact & Figures, issues, technical solutions and development opportunities, March 2012.* +- [b-ESA] *Energy storage systems – Characteristics and comparisons, H. Ibrahim, A. Ilinca, J. Perron, Wind Energy Research Laboratory (WERL), Université du Québec Canada, January 2007.* +[https://www.researchgate.net/publication/223915340\\_Energy\\_storage\\_systems-Characteristics\\_and\\_comparisons](https://www.researchgate.net/publication/223915340_Energy_storage_systems-Characteristics_and_comparisons) +- [b-EU Mandate] European Commission Smart Grid Mandate (2011), *Standardisation Mandate to European Standardisation* + +*Organisations (ESOs) to support European Smart Grid deployment.* + +[https://ec.europa.eu/energy/sites/ener/files/documents/2011\\_03\\_01\\_mandate\\_m4\\_90\\_en.pdf](https://ec.europa.eu/energy/sites/ener/files/documents/2011_03_01_mandate_m4_90_en.pdf) + +- [b-eurelectric] +- [b-IADC] IADC UBO/MPD Glossary (2011), Global Standards. + +- [b-IEC 60050-826] IEC 60050-826 (2004), *International Electrotechnical Vocabulary – Part 826: Electrical installations.* +- [b-IEC 60896-X] IEC 60896 series *Stationary lead-acid batteries.* +This reference includes the following 3 parts: +- IEC 60896-11:2002, *Stationary lead-acid batteries – Part 11: Vented types – General requirements and methods of tests.* + - IEC 60896-21:2004, *Stationary lead-acid batteries – Part 21: Valve regulated types – Methods of test.* + - IEC 60896-22:2004, *Stationary lead-acid batteries – Part 22: Valve regulated types – Requirements.* +- [b-IEC 62619] IEC 62619 (Fev 2017), *Secondary cells and batteries containing alkaline or other non-acid electrolytes – Safety requirements for secondary lithium cells and batteries, for use in industrial applications.* +- [b-IEC 62620] IEC 62620 (Nov 2014), *Secondary cells and batteries containing alkaline or other non-acid electrolytes – Secondary lithium cells and batteries for use in industrial applications.* +- [b-IEC WPstorage] IEC Energy storage White paper. + +- [b-IRES + ESE 2016-T&E] International IRES and European ESE conference, Dusseldorf, 15-17 March 2016. +- [b-peak shaving] IADC drilling lexicon. + +- [b-RSE report] RSE report, *L'accumulo di energia elettrica – 2011.* +- [b-Soogreen] Rocha, H. et al. 2017, *SooGREEN: Service-oriented optimization of Green mobile networks*, International workshop on service-oriented optimization of Green Mobile Networks. + + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1222-201805-I_PDF-E/0ba998c66ef6a980bac9c0c12e9452bf_img.jpg b/marked/L/T-REC-L.1222-201805-I_PDF-E/0ba998c66ef6a980bac9c0c12e9452bf_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..77aec4458a60afdc2ffb6c30e13cf52b7e8235c6 --- /dev/null +++ b/marked/L/T-REC-L.1222-201805-I_PDF-E/0ba998c66ef6a980bac9c0c12e9452bf_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:4acbdf291c47dd691edae812c92259c1d7865b58689ad83acb4e8738f25d86a8 +size 22115 diff --git a/marked/L/T-REC-L.1222-201805-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg b/marked/L/T-REC-L.1222-201805-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..436da45afeb447e57e78ece3451cc159ca1ea010 --- /dev/null +++ b/marked/L/T-REC-L.1222-201805-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:848300dabb824f731342024c6a672aeb6357bb068a70acc42e93445d1e7edb1e +size 3794 diff --git a/marked/L/T-REC-L.1222-201805-I_PDF-E/d3f6de4fe9f9138fc6afc584b5104433_img.jpg b/marked/L/T-REC-L.1222-201805-I_PDF-E/d3f6de4fe9f9138fc6afc584b5104433_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..0e251068d8a2cbef9d5524bdd1b4af9e09bc2e5d --- /dev/null +++ b/marked/L/T-REC-L.1222-201805-I_PDF-E/d3f6de4fe9f9138fc6afc584b5104433_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:9d571dae783585904dbdd169a66e658ca372fbbca46a60c42ac35ca08554d8c0 +size 51556 diff --git a/marked/L/T-REC-L.1222-201805-I_PDF-E/ddc7460821484f1ae2835c67955c554c_img.jpg b/marked/L/T-REC-L.1222-201805-I_PDF-E/ddc7460821484f1ae2835c67955c554c_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..f9febb5a60d6f91f97beb780ea181530fff320c0 --- /dev/null +++ b/marked/L/T-REC-L.1222-201805-I_PDF-E/ddc7460821484f1ae2835c67955c554c_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:c000eb811a6dbe6e752c2cd5dd66a8feb478cbfd1f2da1419aa6cf035ce259ee +size 18397 diff --git a/marked/L/T-REC-L.1222-201805-I_PDF-E/fd955384881fd240be5518d3050588d9_img.jpg b/marked/L/T-REC-L.1222-201805-I_PDF-E/fd955384881fd240be5518d3050588d9_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..419eae48de3058391ba5f8ebd2ce344b5f02389a --- /dev/null +++ b/marked/L/T-REC-L.1222-201805-I_PDF-E/fd955384881fd240be5518d3050588d9_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:b4add544f9a34c4a46dc650dff1f6722c62f28f9f205c3ce522aa4b96dd0beb5 +size 38746 diff --git a/marked/L/T-REC-L.1222-201805-I_PDF-E/raw.md b/marked/L/T-REC-L.1222-201805-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..002eec110f09caa4afba1d47fc9ab14b652a7985 --- /dev/null +++ b/marked/L/T-REC-L.1222-201805-I_PDF-E/raw.md @@ -0,0 +1,390 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.1222** + +(05/2018) + +SERIES L: ENVIRONMENT AND ICTS, CLIMATE +CHANGE, E-WASTE, ENERGY EFFICIENCY; +CONSTRUCTION, INSTALLATION AND PROTECTION +OF CABLES AND OTHER ELEMENTS OF OUTSIDE +PLANT + +--- + +**Innovative energy storage technology for +stationary use – Part 3: Supercapacitor +technology** + +Recommendation ITU-T L.1222 + +# ITU-T L-SERIES RECOMMENDATIONS + +## **ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT** + +| | | +|--------------------------------------------------------|-------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node elements (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +## Recommendation ITU-T L.1222 + +# Innovative energy storage technology for stationary use – Part 3: Supercapacitor technology + +## Summary + +Recommendation ITU-T L.1222 is based on Recommendation ITU-T L.1220 and is the part related to supercapacitors. + +Recommendation ITU-T L.1222 contains selection criteria for telecommunication application based on main performance parameters and the methods for proper use. In addition, some use cases and examples are given in an Appendix to help users. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.1222 | 2018-05-14 | 5 | 11.1002/1000/13579 | + +## Keywords + +Direct current, double layer capacitor, energy storage, micro-interruptions, next generation access network, battery, supercapacitor. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2018 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|--------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 1 | +| 4 Abbreviations and acronyms ..... | 1 | +| 5 Conventions ..... | 2 | +| 6 General introduction to supercapacitors ..... | 2 | +| 7 Working principle ..... | 3 | +| 8 Supercapacitor technology and performance..... | 4 | +| 9 Applications..... | 5 | +| 10 Economic and environmental topics..... | 5 | +| Appendix I – Certification information ..... | 6 | +| I.1 General ..... | 6 | +| Appendix II – Application examples ..... | 7 | +| II.1 General ..... | 7 | +| Bibliography..... | 9 | + +# Introduction + +This Recommendation is part 3 of a series covering innovative energy storage technology for stationary use. This series introduces the evolution of energy storage technologies applicable for use with stationary information and communication technology/telecommunication (ICT/TLC) equipment and provides global results of investigations in laboratories or from field tests in TLC/ICT network or customer premises (e.g., for resilience in a smart sustainable city). Mobile and portable batteries lie outside the scope of this Recommendation. + +Identified parts of this Recommendation series, *Innovative energy storage technology for stationary use*, are: + +- *Part 1: Overview of energy storage;* +- *Part 2: Battery systems;* +- *Part 3: Supercapacitor technology.* + +This Recommendation was developed jointly by ETSI TC EE and ITU-T Study Group 5 and published respectively by ITU and ETSI as Recommendation ITU-T L.1222 and ETSI Standard ETSI TS 103 533-3, which are technically equivalent. + +## Recommendation ITU-T L.1222 + +## Innovative energy storage technology for stationary use – Part 3: Supercapacitor technology + +# 1 Scope + +This Recommendation provides an overview of available supercapacitor (SC) technology, with details of SC characteristics (electrical, mechanical, thermal) and applicability in the telecommunication/information and communication technology (TLC/ICT) domain [b-ETSI TR 102 532]. + +A general overview of the evolution of energy storage technologies is provided in [ITU L.1220]. + +The adoption of SC technology is recommended for coverage of micro-interruptions of the public grid for indoor and outdoor applications. + +Examples of sizing and essential tests used in the network are described. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T L.1220] Recommendation ITU-T L.1220 (2017), *Innovative energy storage technology for stationary use – Part 1: Overview of energy storage*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following term defined elsewhere: + +**3.2.1 electrochemical capacitor; supercapacitor** [b-IEC 60050-114]: Device that stores energy using a double layer in an electrochemical cell. + +## 3.2 Terms defined in this Recommendation + +None. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +AC            Alternating Current + +CO            Central Office + +DC            Direct Current + +ELDC        Electric Double Layer Capacitor + +FTTCab    Fibre To The Cabinet + +FTTx        Fibre To The x (x:= E = Exchange; B = Building; dP = distribution Point; H = Home) + +| | | +|------|--------------------------------------| +| ICT | Information Communication Technology | +| MTBF | Mean Time Between Failures | +| NGAN | Next Generation Access Network | +| RMS | Root Mean Square | +| SC | Supercapacitor | +| SELV | Safety Extra Low Voltage | +| TLC | Telecommunication | +| UBB | Ultrabroadband | +| VAC | Volt Alternating Current | +| VDC | Volt Direct Current | + +# 5 Conventions + +None. + +# 6 General introduction to supercapacitors + +SCs store electrical energy in the form of electrical charges in two electrodes and an electric field between them. They have very low internal impedance and can be recharged in seconds. They are characterized by very high values of specific power (watts per kilogram) and are particularly suitable for peak power applications. + +On the other side, the specific energy (watt hours per kilogram or watt hours per litre) of SCs is much lower (about 10 times) than that of batteries and, in addition on discharge the voltage decreases from the nominal voltage to zero, thus limiting the useful energy in actual applications approximately to a quarter of the available energy (dictated by the minimum operational voltage of the apparatus). + +In summary, SCs are very good in providing peak power demands, but they store low amounts of useful energy and cannot replace batteries in the majority of current applications. When integrated with a battery, SCs can significantly increase the high rate performance of storage systems and extend overall service life, as they can reduce high power drains from batteries, thus reducing battery degradation. + +Figure 1 shows a typical example of a high-power SC bank, e.g., for peak power shaving and Figure 2 shows a typical SC used for fibre to the x (FTTx) applications in the active access network. + +![Figure 1: A photograph of a supercapacitor bank. It is a large, rectangular metal enclosure with a transparent front panel, revealing multiple rows of supercapacitor modules mounted on a rack. At the bottom of the unit, two large circular cooling fans are visible.](fd955384881fd240be5518d3050588d9_img.jpg) + +Figure 1: A photograph of a supercapacitor bank. It is a large, rectangular metal enclosure with a transparent front panel, revealing multiple rows of supercapacitor modules mounted on a rack. At the bottom of the unit, two large circular cooling fans are visible. + +**Figure 1 – Example of a supercapacitor bank, 360 VDC – 150 kW 320 Wh** + +![Figure 2: Two side-by-side photographs of supercapacitor modules. The module on the left is labeled '- 25' and the one on the right is labeled '- 100'. Both labels show technical specifications including Nominal Voltage (48 VDC), Max. Transit Current (3.7 A and 30.5 A), Max. Operating Discharge Current (1.1 A and 10 A), Energy / Capacity (0.50 Wh and 1.6 Wh), and Operative Temperature (-40° to +70°). Both also feature the CE mark and 'MADE IN ITALY'.](0ba998c66ef6a980bac9c0c12e9452bf_img.jpg) + +Figure 2: Two side-by-side photographs of supercapacitor modules. The module on the left is labeled '- 25' and the one on the right is labeled '- 100'. Both labels show technical specifications including Nominal Voltage (48 VDC), Max. Transit Current (3.7 A and 30.5 A), Max. Operating Discharge Current (1.1 A and 10 A), Energy / Capacity (0.50 Wh and 1.6 Wh), and Operative Temperature (-40° to +70°). Both also feature the CE mark and 'MADE IN ITALY'. + +**Figure 2 – Examples of supercapacitors for fibre to the x (0.5 Wh at 48 VDC on left – 1.6 Wh at 48 VDC on right) frontal view** + +SC modules are installed between the alternating current/direct current (AC/DC) converter (e.g., 230 VAC/60 VDC) and the TLC load, so that the TLC equipment can be powered at a safety extra low voltage (SELV) level, with primary energy source from public mains, without usage of standby batteries. These SC modules are able to provide uninterrupted power for micro-interruptions from the mains (e.g., power outages of less than few seconds), to avoid the rebooting of TLC/ICT systems (usually taking several minutes to bring back TLC/ICT service, as described in Appendix III of [ITU-T L.1220]). + +Operating temperature and cell voltage impact on SCs lifetime. + +High temperature and a working voltage close to the nominal voltage reduce the lifetime. + +Based on that, the designer can improve the lifetime by: + +- reducing the working temperature; +- reducing the cell working voltage, e.g., by using more cells in series. + +# **7 Working principle** + +SCs are devices that are able to store more electrical energy than equivalent electrostatic capacitors. They use positive and negative metallic plates (generally cylindrically shaped) with very large active surface and very short distance between the plates (e.g., 0.1 nm). + +A SC consists of two electrodes, placed on aluminium supports that act as current collectors, with a dielectric separator and electrolyte between the electrodes. + +Electrodes are made of porous materials, to create a larger contact surface available for the electrolyte. The dielectric separator, generally made of paper, plastic or ceramic, is needed to block the transfer of electrons inside the SC, meanwhile offering a high permeability for electrolyte ions. + +A potential difference, applied across the terminals of a SC, starts a process of separation of electrolyte ions, which generates a double layer of charge on the electrode/electrolyte interfaces. In particular, the voltage applied causes electrons to gather on the positive electrode and to the deposition of positive ionic charge on the interface with the electrolyte. In a similar way, a surplus of positive charges will be present on the negative electrode and negative ionic charge will reside on the interface with the electrolyte (see Figure 3). + +In SCs the storage of energy is performed through a reversible process of very quick charge transfer, without redox chemical processes. This allows fast charge and discharge of SCs, with a higher number of lifecycles compared to traditional electrochemical capacitors. + +The very short distance between the two electrodes results in high values for the internal electrical fields, whose strength can approach the dielectric strength of the dielectric material. This implies the adoption of a voltage limitation between the electrodes and of the associated stored energy. + +SCs are devices that are able to give high levels of power in a short time, and with very high numbers of charge and discharge cycles. These features of SCs allow them to be used in applications, such as compensation for power fluctuations in the electrical grids and for voltage regulation (power quality application, to improve voltage waveform). + +![Figure 3: Cylindrical supercapacitor and schematic of the double layer of charge. The left side shows a 3D cutaway of a cylindrical supercapacitor with labels: Positive terminal, Negative terminal, External case, Negative electrode, Separator, and Positive electrode. The right side is a schematic diagram showing the internal structure: Positive electrode (+), Negative electrode (-), Electrolyte, and Separator. The schematic illustrates the double layer of charge at the electrode/electrolyte interfaces, with positive ions (circles with +) on the negative electrode side and negative ions (circles with -) on the positive electrode side.](d3f6de4fe9f9138fc6afc584b5104433_img.jpg) + +Figure 3: Cylindrical supercapacitor and schematic of the double layer of charge. The left side shows a 3D cutaway of a cylindrical supercapacitor with labels: Positive terminal, Negative terminal, External case, Negative electrode, Separator, and Positive electrode. The right side is a schematic diagram showing the internal structure: Positive electrode (+), Negative electrode (-), Electrolyte, and Separator. The schematic illustrates the double layer of charge at the electrode/electrolyte interfaces, with positive ions (circles with +) on the negative electrode side and negative ions (circles with -) on the positive electrode side. + +Figure 3 – Cylindrical supercapacitor and schematic of the double layer of charge + +# 8 Supercapacitor technology and performance + +Table 1 provides data on the main SC performance parameters. The nominal voltage of an SC cell is dependent on its construction and the type of electrolyte (higher for organic electrolytes and lower for aqueous ones). SC specific energy is very low in general, since these devices are mainly intended to be used against transient power interruptions, not for energy back-up. Expected cycling lifetime, can reach values in the range of 500 000 to 1 000 000 cycles (with voltage ranging from a maximum value to half maximum during the working cycle). + +**Table 1 – SC performance parameters** + +| Parameter | Typical values | +|----------------------------------|------------------------------| +| Nominal Voltage (V) | 1-2.7 | +| Capacity (F) | 1-5000 | +| Specific power (W/kg) | 300-100 000 | +| Specific energy (Wh/kg) | 0.5-10 | +| Energy efficiency (%) | 95-98 | +| Daily self-discharge (%) | 20-40 | +| Expected life-time (years) | 5-10 | +| Number of cycles | >50 000 | +| Temperature operating range (°C) | –40-65 | +| Auxiliary system | balancing system of the cell | + +NOTE – The lifetime is impacted by the capacitor temperature and root mean square (RMS) current, as high values can increase the working temperature. + +# 9 Applications + +Applications for SC technology are related to next generation access networks (NGANs), using active loads spread outside traditional central offices (COs). In such a scenario, a TLC active load is generally supplied from the local public mains (in some cases, TLC loads are remotely powered from COs, with power backup provided by battery). In this case, use of an SC is of interest for coverage of grid micro-interruptions, which can cause several ultrabroadband (UBB) service downtime periods, due to TLC equipment reboots (see Appendix III of [ITU L.1220] for further details). + +In field applications (e.g., FTTx deployments), SC units are controlled by internal electronic circuit, in order to properly manage charge and discharge phases. During the SC charge phase, a current limitation circuit manages the storage of energy in SC cells, to enable short recharging times (tenths of a second) and to avoid overloads on the power supply unit feeding the TLC load (and associated SC unit). + +Details are given in Appendix II. + +# 10 Economic and environmental topics + +Taking into account their expected long lifetime, SC represent a very low cost for complete cycles of charge and discharge compared with traditional electrochemical storage systems that are more commonly defined in cost per kilowatt hour. + +The most evident limit of SC is their very low autonomy (up to a few seconds, as a maximum). SCs do not have problems from the environmental point of view, since their construction materials are not toxic. If organic electrolytes are used, attention must be paid to the presence of inflammable, irritant and corrosive solvents, as for solvents in lithium/ion batteries. + +To date, the disposal of SCs has been dealt with like any other piece of electronic equipment. Their recycling process is economically convenient, due to the presence of aluminium and other metals that can be extracted and reused. + +# Appendix I + +## Certification information + +(This appendix does not form an integral part of this Recommendation.) + +## I.1 General + +In order for SC cells to be used in field applications as power backup units, the following certifications should be provided: + +- certification of single SC cells, provided by the cell manufacturer; +- certification of the whole assembly of the power backup SC unit (e.g., cells, control electronics and power interfaces and case). + +The above certifications have to be granted by a recognized certification organization. + +# Appendix II + +## Application examples + +(This appendix does not form an integral part of this Recommendation.) + +## II.1 General + +The SC unit operates at 59 Vdc (with SELV limits – it may need an electronic circuit adapting voltage to the voltage limits of interface A at the input of ICT equipment) and energy is stored in cells of the electric double layer capacitor (ELDC) type. This stored energy is given to the load when the input voltage from the mains is not present (e.g., micro-interruption). + +Figure II.1 is a schematic of an SC unit for FTTx field application. An SC unit can be subdivided into five main blocks: power input interface (59 Vdc, SELV circuitry is used for this application), output power interface (59 Vdc), protection and section circuitry (responsible for separating the SC cell block from the input interface in the event of power outage on input interface itself, so as to avoid energy flow backwards to input), charge control block (constant current charging phase, up to cell complete recharging) and SC cell block (packaging of $N$ SC cells, ELDC type). + +![Schematic diagram of a supercapacitor unit for fibre to the x application. The diagram shows a horizontal line connecting three blocks: 'Input 59 Vdc', 'Protection and sectioning', and 'Output 59 Vdc'. From the 'Protection and sectioning' block, a vertical line descends to a 'Charge control' block, which in turn descends to a 'Super Cap Cells' block. The label 'L.1222(18)_FII.1' is located to the right of the 'Super Cap Cells' block.](ddc7460821484f1ae2835c67955c554c_img.jpg) + +``` +graph LR; Input[Input 59 Vdc] --- Protection[Protection and sectioning]; Protection --- Output[Output 59 Vdc]; Protection --- Charge[Charge control]; Charge --- SuperCap[Super Cap Cells]; +``` + +Schematic diagram of a supercapacitor unit for fibre to the x application. The diagram shows a horizontal line connecting three blocks: 'Input 59 Vdc', 'Protection and sectioning', and 'Output 59 Vdc'. From the 'Protection and sectioning' block, a vertical line descends to a 'Charge control' block, which in turn descends to a 'Super Cap Cells' block. The label 'L.1222(18)\_FII.1' is located to the right of the 'Super Cap Cells' block. + +**Figure II.1 – Schematic of supercapacitor unit for fibre to the x application** + +Table II.1 gives an example of the electrical and environmental characteristics of an SC used in fibre to the cabinet (FTTCab) network deployments, with regard to two possible types of SC units. + +**Table II.1 – Fibre to the cabinet supercapacitor characteristics** + +| Parameter | Supercapacitor type A | Supercapacitor type B | +|-----------------------------------------------------------------|-----------------------|-----------------------| +| Rated Capacity (F) | 1.136 | 4 | +| Cells | 22 × 25 F | 25 × 100 F | +| Capacity tolerance | −10%/+ 20% | 0 %/+ 20% | +| Accumulated energy at 59 V (J) | 1 977 | 6 962 | +| Minimum available energy (from 59 to 50 V) (J) | 557 | 1 962 | +| Nominal Voltage (V) | 59 | 59 | +| Maximum Voltage (V) | 60 | 60 | +| Maximum current (transit/discharge) (A) | 8 | 25 | +| Charge current (mA) | 700 | 1 000 | +| Leakage current (72 h at 25°C) (mA) | <0.049 | <0.007 3 | +| Mean time between failures (MTBF) at 25°C [b-MIL-HDBK-217F] (h) | >400 000 | >400 000 | +| MTBF at 40°C [b-MIL-HDBK-217F] (h) | > 200 000 | > 200 000 | +| Number of cycles (from $V_n$ to $V_n/2$ at 25°C) | 500 000 | 500 000 | +| Temperature operating range (°C) | −40–+70 | −40–+70 | +| Temperature storage range (°C) | −40–+70 | −40–+70 | + +NOTE – The lifetime is an independent parameter that cannot be derived from the MTBF, e.g., a MTBF of 200 000 h, would give about 18 years, while Table 1 indicates a 5 to 10 year lifetime. + +# Bibliography + +- [b-ETSI TR 102 532] ETSI TR 102 532 V1.2.1 (2012), *Environmental Engineering (EE); The use of alternative energy solutions in telecommunication installations.* +- [b-IEC 60050-114] IEC 60050-114:2014, *International electrotechnical vocabulary.* +- [b-MIL-HDBK-217F] US Department of Defence (1991), *Military handbook: Reliability prediction of electronic equipment, Revision F.* Washington, DC: US Department of Defence. 150 pp. +- [b-RSE] Ricerca sul Sistema Energetico (2011), *L'accumulo di energia elettrica [The accumulation of electrical energy].* Milan: Il Melograno. 10 pp. +[http://www.nuova-energia.com/files/Monografia\\_2011\\_Accumulo\\_prime\\_pagine.pdf](http://www.nuova-energia.com/files/Monografia_2011_Accumulo_prime_pagine.pdf) + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1230-202208-I_PDF-E/0f2a1e4a7b12fe5b8749882ecd636f5c_img.jpg b/marked/L/T-REC-L.1230-202208-I_PDF-E/0f2a1e4a7b12fe5b8749882ecd636f5c_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..c61a24420a289407f711b7607d4ea36d030105e5 --- /dev/null +++ b/marked/L/T-REC-L.1230-202208-I_PDF-E/0f2a1e4a7b12fe5b8749882ecd636f5c_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:92c3e500317a007eca08a37deb7b8f4f2997390eb1beb670d64005f021800e13 +size 75133 diff --git 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(09/2023)** + +SERIES L: Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant + +Power feeding and energy storage + +--- + +### **Methodologies for evaluating the functionality and performance of power supply units configured for servers** + +![ITU logo](0538daaa5583c23e17db3a12f2281a55_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with white lines representing latitude and longitude, and the letters 'ITU' in a bold, blue, sans-serif font overlaid on the globe. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +## **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|--------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| Infrastructure including node elements (except cables) | L.200-L.249 | +| General aspects and network design | L.250-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| Optical fibre cable maintenance | L.300-L.329 | +| Infrastructure maintenance | L.330-L.349 | +| Operation support and infrastructure management | L.350-L.379 | +| Disaster management | L.380-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +## Recommendation ITU-T L.1241 + +## Methodologies for evaluating the functionality and performance of power supply units configured for servers + +# Summary + +Recommendation ITU-T L.1241 provides comprehensive evaluation methods of power supply units configured for servers to evaluate electrical performances, functionalities and safety aspects. + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.1241 | 2023-09-22 | 5 | 11.1002/1000/15599 | + +## Keywords + +Evaluation method, functionality and performance, power supply unit, server. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2023 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +# Table of Contents + +| | | Page | +|-------------|---------------------------------------------------------------------|------| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 3.1 | Terms defined elsewhere ..... | 2 | +| 3.2 | Terms defined in this Recommendation..... | 2 | +| 4 | Abbreviations and acronyms ..... | 2 | +| 5 | Conventions ..... | 2 | +| 6 | Methodology for evaluating performance of a power supply unit ..... | 3 | +| 6.1 | General measurement conditions ..... | 3 | +| 6.2 | Input voltage range ..... | 3 | +| 6.3 | Input rated frequency and frequency fluctuation range..... | 4 | +| 6.4 | Total harmonic distortion (THD) of voltage and current ..... | 4 | +| 6.5 | No-load power consumption ..... | 4 | +| 6.6 | Power factor..... | 4 | +| 6.7 | Energy efficiency..... | 5 | +| 6.8 | PSU level classification..... | 5 | +| 7 | Methodology for evaluating the functionality of PSU ..... | 5 | +| 7.1 | Load distribution management ..... | 6 | +| 7.2 | Monitoring and control..... | 8 | +| 7.3 | Automatic power recovery function..... | 8 | +| 8 | Methodology for evaluating safety and protection of PSU ..... | 8 | +| 8.1 | Insulation resistance and dielectric strength..... | 9 | +| 8.2 | Touch current..... | 9 | +| 8.3 | Resistance of the protective bonding system..... | 9 | +| 8.4 | Flame retardancy of materials ..... | 9 | +| Appendix I | Power factor and energy efficiency in some documents ..... | 10 | +| I.1 | 80 PLUS specification of US Department of Energy ..... | 10 | +| I.2 | Ecodesign requirements of the European Union ..... | 11 | +| I.3 | Procurement requirements of the People's Republic of (China) ..... | 11 | +| I.4 | Certification requirements of China..... | 12 | +| Appendix II | Example of PSU for server testing ..... | 14 | +| II.1 | Test items..... | 14 | +| II.2 | Test samples and data ..... | 14 | +| | Bibliography..... | 19 | + +# Introduction + +Recommendation ITU-T L.1241 describes comprehensive evaluation methods of power supply units (PSUs) for servers to evaluate electrical performances, functionalities and safety aspects. This Recommendation does not deal with the test for servers with PSUs nor the best practices to improve the various characteristics of PSUs, which can be defined in the future. + +Henceforth, with the development of software-defined networking (SDN) and network functions virtualization (NFV) technology, traditional network structures will transition to SDN. Operators will use a large number of general-purpose servers to replace traditional specialized CT devices, which places higher requirements on the stability, security, performance, and other aspects of the servers. It is common for servers to operate without downtime 365 days a year, hence configuring reliable PSUs is crucial. In addition, due to the current environmentally friendly demand for energy conservation and greenhouse gas reduction, it is also necessary to consider the energy efficiency of equipment. But from the perspective of servers, this energy efficiency often refers to the computational power to the energy efficiency ratio. From the energy perspective, the main focus still lies on the energy efficiency of PSU. + +The motivations for developing a comprehensive evaluation method regarding the functionality and performance of PSU for servers are as follows: + +- Currently, the evaluation of PSU is mostly focused on energy efficiency, which is an important factor but is not comprehensive enough. There exist several server energy efficiency certification methods that are used in the industry. The certification methods classify the efficiency of servers into several levels based on the efficiency. However, as the server technology progresses, it is not difficult to achieve the highest level of certification that considers the energy efficiency only. Further, considering only the energy efficiency of PSU cannot provide a full understanding of the various characteristics of PSU, such as the power supply system that PSU can support, no-load power consumption, load distribution management methods, safety and protection of PSU, and so on. Therefore, it is necessary to establish a more comprehensive evaluation method to evaluate the various aspects of PSU including the electrical performances, functionalities, and safety. +- The server manufacturers usually do not develop and produce PSUs instead they adopt PSUs from PSU vendors. Thus, it is necessary to choose adequate PSUs based on the requirements and evaluation of PSUs. To check whether the PSU requirements for the servers are met or not, a comprehensive consideration is needed to fully understand the characteristics of PSU. +- From the user's point of view, when a user purchases a server, the configured PSU is integrated with the server. However, there exists no evaluation method for PSU characteristics, so it is difficult for users to determine the reliability and safety of the server and PSU. The difficulty can cause an unexpected problem for the safe operation of the server. If the evaluation methods for PSUs are developed, users can easily refer to the evaluation methods to test and evaluate the performance of the purchased PSUs. +- The development of the evaluation methods for PSU can also guide the technical progress of PSU manufacturers to meet the needs of the users. It can also guide server manufacturers to pay attention to PSU, avoiding the problem of server manufacturers' low motivation for supporting more energy-saving and efficient power supply methods. + +## Recommendation ITU-T L.1241 + +## Methodologies for evaluating the functionality and performance of power supply units configured for servers + +# 1 Scope + +This Recommendation provides comprehensive evaluation methods of power supply units configured for servers to evaluate electrical performances, functionalities and safety aspects. + +The functional features and performances evaluated mainly include input voltage range and rated frequency, total harmonic distortion (THD) of voltage and current, no-load power consumption, power factor, energy efficiency, load distribution management, telemetry, telecommunication, telecontrol, safety and protection. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T L.1200] Recommendation ITU-T L.1200 (2012), *Direct current power feeding interface up to 400 V at the input to telecommunication and ICT equipment.* +- [ITU-T L.1206] Recommendation ITU-T L.1206 (2017), *Impact on ICT equipment architecture of multiple AC, -48VDC or up to 400 VDC power inputs.* +- [ITU-T L.1310] Recommendation ITU-T L.1310 (2020), *Energy efficiency metrics and measurement methods for telecommunication equipment.* +- [ITU-T L.1315] Recommendation ITU-T L.1315 (2017), *Standardization terms and trends in energy efficiency.* +- [EN 50563] CENELEC EN 50563:2011, *External a.c. – d.c. and a.c. – a.c. power supplies – Determination of no-load power and average efficiency of active modes.* +- [ETSI EN 300 132-1] ETSI EN 300 132-1 v2.1.0 (2019), *Environmental Engineering (EE); Power supply interface at the input to Information and Communication Technology (ICT) equipment; Part 1: Alternating Current (AC).* +- [IEC 60038] IEC 60038:2009, *IEC standard voltages.* +- [IEC 60332-1-2] IEC 60332-1-2:2004/AMD1:2015, *Tests on electric and optical fibre cables under fire conditions – Part 1-2: Test for vertical flame propagation for a single insulated wire or cable – Procedure for 1 kW pre-mixed flame.* +- [IEC 60990] IEC 60990:2016, *Methods of measurement of touch current and protective conductor current.* +- [IEC 61000-2-2] IEC 61000-2-2:2002/AMD1:2017, *Amendment 1 – Electromagnetic compatibility (EMC) – Part 2-2: Environment – Compatibility levels for low-frequency conducted disturbances and signalling in public low-voltage power supply systems.* + +- [IEC 61000-3-2] IEC 61000-3-2:2018+AMD1:2020, *Electromagnetic compatibility (EMC) – Part 3-2: Limits – Limits for harmonic current emissions (equipment input current $\leq 16$ A per phase)*. +- [IEC 61000-4-7] IEC 61000-4-7:2002/A1:2009, *Electromagnetic compatibility (EMC) – Part 4-7: Testing and measurement techniques – General guide on harmonics and interharmonics measurements and instrumentation, for power supply systems and equipment connected thereto*. +- [IEC 61180] IEC 61180:2016, *High-voltage test techniques for low-voltage equipment – Definitions, test and procedure requirements, test equipment*. +- [IEC 61558-1] IEC 61558-1:2017, *Safety of transformers, reactors, power supply units and combinations thereof – Part 1: General requirements and tests*. +- [IEC 62301] IEC 62301:2011, *Household electrical appliances – Measurement of standby power*. +- [IEC 62368-1] IEC 62368-1:2023, *Audio/video, information and communication technology equipment – Part 1: Safety requirements*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 energy efficiency (EE)** [b-ITU-T L.1350]: The relation between the useful output and energy consumption. + +**3.1.2 power** [b-ITU-T L.1330]: The rate at which energy is transmitted. Power is measured in units of watts. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following term: + +**3.2.1 power supply unit for server**: A power conversion unit embedded in the server equipment to convert alternating current (AC) or up to 400 volts direct current (VDC) input voltage into low voltage. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-----|---------------------------| +| AC | Alternating Current | +| DC | Direct Current | +| EE | Energy Efficiency | +| PSU | Power Supply Unit | +| THD | Total Harmonic Distortion | +| VDC | Volts Direct Current | + +# 5 Conventions + +None. + +# 6 Methodology for evaluating performance of a power supply unit + +This clause includes evaluation methods of performance indicators such as input voltage range, input rated frequency and frequency fluctuation range, total harmonic distortion (THD), power factor, no-load power consumption, and energy efficiency. + +The test schematic can be seen in Figure 1. Since the output of the power supply unit (PSU) is direct current (DC) voltage, according to the reactance formula $Z = R + jX$ , the impact of capacitive or inductive loads on the performance evaluation of the PSU can be ignored. Therefore, using resistive loads in the evaluation method without considering inductive or capacitive loads can effectively evaluate the performance of PSUs. + +![Figure 1 – Test schematic of PSU. The diagram shows a test setup where an 'AC and DC regulated adjustable power supply' is connected to the input of a 'PSU under test'. The input side includes a power meter (W), an ammeter (A), and a voltmeter (V). The output of the PSU is connected to an 'Adjustable resistive load', also with a power meter (W), an ammeter (A), and a voltmeter (V). A legend at the bottom identifies the symbols: A for Ammeter, V for Voltmeter, and W for Power meter. The reference code L.1241(23) is shown in the bottom right corner of the diagram area.](b3baf3a29b67c7425d2562ddbc52f0cc_img.jpg) + +A Ammeter    V Voltmeter    W Power meter + +L.1241(23) + +Figure 1 – Test schematic of PSU. The diagram shows a test setup where an 'AC and DC regulated adjustable power supply' is connected to the input of a 'PSU under test'. The input side includes a power meter (W), an ammeter (A), and a voltmeter (V). The output of the PSU is connected to an 'Adjustable resistive load', also with a power meter (W), an ammeter (A), and a voltmeter (V). A legend at the bottom identifies the symbols: A for Ammeter, V for Voltmeter, and W for Power meter. The reference code L.1241(23) is shown in the bottom right corner of the diagram area. + +Figure 1 – Test schematic of PSU + +## 6.1 General measurement conditions + +### 6.1.1 Environmental conditions + +As specified in [ITU-T L.1310], the PSU should be evaluated at an ambient temperature of $25 \pm 3$ °C, relative humidity of 30% to 75%, and a site pressure between 860 to 1 060 hPa. + +### 6.1.2 Electrical conditions + +According to [ITU-T L.1315], the assessment methods of performance indicators for PSU with DC input voltage shall be evaluated at $\pm 4\%$ of the specified float voltage. PSU with alternating current (AC) input voltage shall be evaluated at $\pm 5\%$ of the specified voltage and $\pm 1\%$ of the specified frequency. + +The assessment methods of clauses 6.2 and 6.3 are not applicable to clause 6.1.2 completely. + +## 6.2 Input voltage range + +The PSU currently on the market can be supplied by an AC power, up to 400 VDC power, or hybrid power supply modes. The input voltage range of the PSU reflects the adaptability of the PSU to the fluctuation tolerance of the input voltage. + +The nominal voltage for an AC grid source of 230 V single phase and 400 V three phase is defined according to [IEC 60038]. In addition, a wide worldwide nominal single phase AC voltage range from 100 V to 240 V is commonly used, along with a corresponding nominal 3 phase voltage range from 173 V to 415 V. + +The AC input voltage of the PSU shall comply with the specified nominal voltage above. According to [IEC 60038], the supply voltage should not differ from the nominal voltage of the system by more than $\pm 10\%$ , and the voltage drop recommended should not be greater than 4%. When taking voltage drops into account, [ETSI EN 300 132-1] gives the calculation method of the input voltage range. For PSU with up to 400 VDC input voltage, the minimum and maximum voltages refer to [ITU-T L.1200]. + +NOTE 1 – Product manufacturers can use a wide voltage range as the input voltage range of the PSU in order to apply for different nominal voltage systems in different regions. + +NOTE 2 – According to the capabilities of product manufacturers, the allowable input voltage range of the PSU in practice may slightly exceed the specified voltage range within a certain limit. + +To evaluate whether the PSU can work normally within a certain input voltage range, the test methods shall refer to [ETSI EN 300 132-1] for AC input and [ITU-T L.1200] for DC input. + +## **6.3 Input rated frequency and frequency fluctuation range** + +The input rated frequency of PSU with AC input voltage is specified according to the frequency adopted by each country and region, and the rated frequency adopted by most countries and regions is 50 Hz or 60 Hz. At present, the input frequency fluctuation range of PSU produced by manufacturers usually ranges from 47 Hz to 63 Hz, so that the PSU can be used in these areas. For this reason, the range of $\pm 5\%$ of the rated frequency is recommended. + +The evaluation method is to verify whether the PSU with AC input voltage can work normally when the input frequency is at the rated frequency as well as within the input frequency fluctuation range. + +The test procedure should be as follows: + +Step 1 – Connect the circuit according to Figure 1 and start PSU. Adjust the AC input voltage and frequency to meet the requirements in clause 6.1.2. The PSU shall work normally. + +Step 2 – Adjust the input frequency to a lower-frequency limit, and the DC output with full load current. The PSU shall work normally. + +Step 3 – Adjust the input frequency to the upper-frequency limit, and the DC output with full load current. The PSU shall work normally. + +## **6.4 Total harmonic distortion (THD) of voltage and current** + +Total harmonic distortion (THD) of voltage and current produced by PSU can be injected into the public supply system. In order to reduce the impact of THD on the public supply system, it is necessary to limit them. + +The compatibility level for the total harmonic distortion of voltage is 8% specified in [IEC 61000-2-2]. The limits of total harmonic distortion of current for PSU can be referred to [IEC 61000-3-2]. Testing and measurement techniques can be referred to [IEC 61000-4-7]. + +It should be noted that the THD of PSU may be better than the compatibility level according to different regions' regulations. + +## **6.5 No-load power consumption** + +No-load power consumption is used to evaluate the input active power consumption of the PSU in hot standby mode, where PSU can provide immediate operation upon demand. In general, no-load power consumption is positively correlated with the rated power of the PSU. + +Based on the main product series of PSUs in the market, most mainstream manufacturers can achieve no-load power consumption of PSUs within 1% of rated power, some examples of test results are in Appendix II. The no-load consumption can reach even stricter targets in practice as technical solutions appearing on the market show this to be feasible, but the cost will definitely be higher. + +The test of no-load power consumption shall be made in accordance with [IEC 62301] but with the AC and DC cables provided with the product [EN 50563]. + +## **6.6 Power factor** + +The power factor refers to the ratio of the active power to the apparent power of the AC circuit. Power factor is an important technical indicator for PSU with AC input, as it reflects the efficiency of the + +PSU in utilizing the electrical energy provided by the power supply. Considering its environmental impact, it would be better if this indicator were as high as possible at a certain load rate. + +In order to evaluate this indicator, some documents in different regions (see Appendix I) provide the specified values of the power factor for PSU with different load rates (e.g., 20%, 50%, 100% of rated load), so as to represent the power factor performance of PSU under low load, half load, and full load operating conditions. + +The test procedure should be as follows: + +Step 1 – Connect the circuit according to Figure 1 and start PSU. Adjust the AC input voltage and frequency to meet the requirements in clause 6.1.2. The PSU shall work normally. + +Step 2 – Adjust the load current to different load rates respectively and read the input power factor on the power quality analyser. + +## **6.7 Energy efficiency** + +Energy efficiency (EE) is an important indicator for evaluating the performance of PSU, which can reflect the energy utilization efficiency of PSU under normal operating conditions. The goal of all users and manufacturers is to maximize the energy efficiency (EE) of PSU at different load rates. Considering the balance between technical capabilities and costs, this indicator is often graded in relevant documents or standards in different regions for users and manufacturers to make reasonable choices. However, in the current context of low-carbon and sustainable development, the requirements of energy efficiency (EE) for PSU will become increasingly strict. (Appendix I provides requirements on power factor and energy efficiency in some documents.) + +In order to evaluate this indicator, it is necessary to adjust the output of the PSU at different load rates respectively, e.g., 10%, 25%, 50%, 75%, and 100%. The test methods shall be made in accordance with the [ITU-T L.1310]. + +The test procedure should be as follows: + +Step 1 – Connect the circuit according to Figure 1 and start PSU. Adjust the AC input voltage and frequency to meet the requirements in clause 6.1.2. The PSU shall work normally. + +Step 2 – Adjust the load current to different load rates respectively and record the efficiency on the power quality analyser. + +## **6.8 PSU level classification** + +PSU can be classified on different levels (e.g., Level 1, Level 2, Level 3...) depending on their characteristic. According to customer needs, manufacturers need to declare at which level their PSU can be classified. + +The basis for PSU level classification may not be a unified classification standard, as different certification requirements vary in different regions, and customers can also customize according to their own needs due to the cost and performance considerations. + +Normally, PSU levels can be classified according to its energy efficiency (see 80 PLUS in Appendix I). No-load power consumption can also be used as the classification basis for PSU, but this indicator is often related to the rated power of PSU, for PSU with higher rated power may have more complex internal circuits. Therefore, when level classification is based on this indicator, it is necessary to consider the rated power of PSUs. + +# **7 Methodology for evaluating the functionality of PSU** + +This clause includes evaluation methods of functionality features such as load distribution management, telemetry, telecommunication, telecontrol, and automatic power recovery functions. + +The test schematic is seen in Figure 2. + +![Figure 2: Test schematic of PSU. The diagram shows an AC and DC regulated adjustable power supply connected to two PSUs under test. The PSUs are connected in parallel to an adjustable resistive load. Ammeters (A) and voltmeters (V) are used to measure the current and voltage at various points in the circuit. A legend at the bottom identifies the symbols for Ammeter (A) and Voltmeter (V). The reference L.1241(23) is noted in the bottom right corner.](007b053fe94a8348f75128a584503fd0_img.jpg) + +Figure 2: Test schematic of PSU. The diagram shows an AC and DC regulated adjustable power supply connected to two PSUs under test. The PSUs are connected in parallel to an adjustable resistive load. Ammeters (A) and voltmeters (V) are used to measure the current and voltage at various points in the circuit. A legend at the bottom identifies the symbols for Ammeter (A) and Voltmeter (V). The reference L.1241(23) is noted in the bottom right corner. + +**Figure 2 – Test schematic of PSU** + +## 7.1 Load distribution management + +A server may be configured with two or more PSUs. These PSUs may have architectures of N, 2N or N+M ( $M < N$ ) in practical use for a server. + +- PSUs with architectures of N can be seen in Figure 3. The total number of PSUs is N, which can provide power to the server with one single power source input. +- PSUs with architectures of 2N can be seen in Figure 4. The total number of PSUs is 2N, which are evenly divided into 2 sets with different power source inputs for each set. +- PSUs with architectures of N+M ( $M < N$ ) can be seen in Figure 5. The total number of PSUs is N+M, which are divided into 2 sets with one set being N and the other set being M. These two sets have different power source inputs. + +It is necessary to consider the load distribution management function of PSUs to achieve a better work performance. During the operation of multiple PSUs, there are several control mechanisms such as load distribution and even an imbalanced operation with a single PSU. It should carefully select how to control the operation of multiple PSUs based on the characteristics of power sources and server loads. When power conversion efficiency drops due to a light load operation with load distribution control, there is a case of operation with a load rate of better efficiency by controlling the number of PSUs. On the other hand, rather than load balancing of multiple PSUs, there is a case of imbalanced operation with a single PSU, which may bring better energy efficiency. + +The load distribution management function is controlled by the system monitoring unit. In load distribution management, it is necessary to consider the load sharing performance of the working PSUs, because it will affect the overall output stability and service life of the system. The imbalance of output current sharing can be used to evaluate the load sharing performance of the PSU. + +### 7.1.1 Load sharing mode + +![Figure 3: PSUs with the architecture of N. The diagram shows a single power source connected to a server containing N PSUs (PSU1, PSU2, ..., PSUn). The PSUs are connected in parallel to the server load. The reference L.1241(23) is noted in the bottom right corner.](fbfa653853daf5541118a9ddecb92284_img.jpg) + +Figure 3: PSUs with the architecture of N. The diagram shows a single power source connected to a server containing N PSUs (PSU1, PSU2, ..., PSUn). The PSUs are connected in parallel to the server load. The reference L.1241(23) is noted in the bottom right corner. + +**Figure 3 – PSUs with the architecture of N** + +When there are multiple PSUs working with the architecture of N in the condition of one single power source input (e.g., either AC or up to 400 VDC input from one power source), it is necessary to consider the load sharing performance of these PSUs, which can be evaluated by testing the imbalance of output current sharing. When one PSU fails, the others will automatically bear all the loads and redistribute the load, so that the output voltage and current shall keep working continuously. The load sharing of each PSU output is recommended not to be imbalanced. + +NOTE – With a light load, the load sharing of each PSU output may be imbalanced. + +The test method for the imbalance of output current sharing should be as follows: + +Step 1 – Connect the circuit according to Figure 2. + +Step 2 – Adjust the input voltage of the tested PSUs to the rated value. Turn on all the tested PSUs one by one and adjust the DC output voltage to the normal working value. + +Step 3 – Set the working mode to load sharing mode. Adjust the load current to 50% and 100% of the rated load value respectively and record the current value of each tested PSU. + +Step 4 – According to the test records, calculate the imbalance of output current sharing of each tested PSU under different output voltage and current. The calculation formula is as follows. + +$$\delta_1 = (K_1 - K) \times 100\%$$ + +$$\delta_2 = (K_2 - K) \times 100\%$$ + +$$\delta_n = (K_n - K) \times 100\%$$ + +$$K_1 = I_1 / I_H$$ + +$$K_2 = I_2 / I_H$$ + +$$K_n = I_n / I_H$$ + +$$K = \sum I / n I_H$$ + +Where, + +$I_1, I_2 \dots I_n$ – output current value borne by each tested PSU + +$I_H$ – rated output current of the tested PSU + +$\sum I$ – total output current of all the tested PSUs. + +### 7.1.2 Optimal efficiency automatic adjustment working mode + +![Figure 4: PSUs with the architecture of 2N. The diagram shows two power sources, 'Power source 1' and 'Power source 2', connected to a 'Server'. The server contains two sets of PSUs, each enclosed in a dashed box labeled 'N'. The first set contains PSUs labeled 'PSU_1' and 'PSU_n'. The second set also contains PSUs labeled 'PSU_1' and 'PSU_n'. All PSUs are connected to a common bus within the server.](c2e3412e6e6d3977856ff9780df32748_img.jpg) + +Figure 4: PSUs with the architecture of 2N. The diagram shows two power sources, 'Power source 1' and 'Power source 2', connected to a 'Server'. The server contains two sets of PSUs, each enclosed in a dashed box labeled 'N'. The first set contains PSUs labeled 'PSU\_1' and 'PSU\_n'. The second set also contains PSUs labeled 'PSU\_1' and 'PSU\_n'. All PSUs are connected to a common bus within the server. + +Figure 4 – PSUs with the architecture of 2N + +In the condition of two different power source inputs (e.g., both AC or up to 400 VDC input from two different power sources, or one set with AC input and the other set with up to 400 VDC input), PSUs with the architecture of 2N (one set is N) can adopt optimal efficiency automatic adjustment + +mode. This mode relies on the communication between PSUs and system monitoring and adjusts the load distribution proportion borne by the two sets of PSUs through negative feedback circuits to achieve optimal work efficiency. The load sharing of each PSU output in one set is recommended not to be imbalanced. + +### 7.1.3 Active and standby working mode + +![Diagram of PSUs with the architecture of N+M. It shows two power sources, Power source 1 and Power source 2, connected to a Server. Power source 1 is connected to a group of N PSUs (PSU1 to PSUn). Power source 2 is connected to a group of M PSUs (PSU1 to PSUm).](4ee27dbf5ef12e7b58b0ef0937bc5a5e_img.jpg) + +``` + +graph LR + subgraph Server + subgraph N_Group [N] + PSU1_N[PSU1] + Dots_N[...] + PSUn_N[PSUn] + end + subgraph M_Group [M] + PSU1_M[PSU1] + Dots_M[...] + PSUm_M[PSUm] + end + end + PS1[Power source 1] --> PSU1_N + PS1 --> PSUn_N + PS2[Power source 2] --> PSU1_M + PS2 --> PSUm_M + +``` + +L.1241(23) + +Diagram of PSUs with the architecture of N+M. It shows two power sources, Power source 1 and Power source 2, connected to a Server. Power source 1 is connected to a group of N PSUs (PSU1 to PSUn). Power source 2 is connected to a group of M PSUs (PSU1 to PSUm). + +**Figure 5 – PSUs with the architecture of N+M** + +In the condition of two different power source inputs (e.g., one set with AC input and another set with up to 400 VDC input), PSUs with the architecture of $2N$ (one set is $N$ ) or $N+M$ (one set is $N$ , another set is $M$ , $M < N$ ), can adopt active and standby mode. In this mode, two sets of PSUs can accept the system monitoring command to make one set to bear all the load, which is called active mode, and the other set automatically in the hot standby state with no load. Hot standby state refers to [ITU-T L.1206]. + +When the load rate of the active set exceeds some specific value, the active and standby working mode is automatically released and may return to the load sharing mode. In the active and standby mode, the load sharing of each PSU output within the active set is recommended not to be imbalanced. + +## 7.2 Monitoring and control + +Monitoring and control are very important functions in controlling and knowing the status of PSU. Monitoring and control refers to the exchange of information between PSU and the information communication equipment. The information that shall be available is as follows: + +- Measured of analogue signal: output voltage and current of the PSU are recommended to be remotely available. +- Alarm/status: Power on/off, high temperature, current limited/unlimited, failure/normal, load distribution management. +- Control/settings: Power on/off, optimal efficiency automatic adjustment working mode, active and standby working mode. + +Test conditions refer to clause 6.1. + +## 7.3 Automatic power recovery function + +After the input power is cut off and restored, the PSU shall be able to automatically return to normal operation in case the PSU has an automatic recovery function. + +# 8 Methodology for evaluating safety and protection of PSU + +This clause includes evaluation methods of safety and protection of the PSU. + +## **8.1 Insulation resistance and dielectric strength** + +For the requirement and measurements of insulation resistance refer to [IEC 61558-1]. The insulation resistance is measured with a DC voltage of approximately 500 V applied, the measurement being made 1 minute after application of the voltage. Insulation resistance between hazardous live parts and the body, input circuits, and output circuits for basic insulation should not be less than 2 M $\Omega$ . + +The dielectric strength test can only be carried out after the PSU passes the insulation resistance test. Immediately after the test of insulation resistance, the insulation is subjected for 1 minute to a dielectric strength voltage of substantially sinusoidal-wave form at 50/60 Hz. The value of the dielectric strength test voltage and the points of application refer to [IEC 61558-1]. Details of the test method to be used are given in [IEC 61180]. + +## **8.2 Touch current** + +The requirement and measurements of the touch current of PSU refers to [IEC 61558-1] and [IEC 60990]. + +## **8.3 Resistance of the protective bonding system** + +The protective bonding system in the PSU consists of a single conductor or a combination of conductive parts, connecting a main protective earthing terminal to a part of the equipment that is to be earthed for safety purposes. Protective bonding conductors and their terminations shall not have excessive resistance. + +The measurement is made between the main protective earthing terminal and each measuring point in the PSU that is required to be earthed. Test method and compliance criteria can be seen in [IEC 62368-1]. + +## **8.4 Flame retardancy of materials** + +As specified in [IEC 62368-1], the flame retardant grade of the printed circuit board used for PSU shall meet the V-0 grade. The flame retardant grade of the plastic insulation layer of the conductor shall meet the requirements in [IEC 60332-1-2], and other plastic materials shall meet the V-1 grade specified in [IEC 62368-1]. + +# Appendix I + +## Power factor and energy efficiency in some documents + +(This appendix does not form an integral part of this Recommendation.) + +## I.1 80 PLUS specification of US Department of Energy + +80 PLUS specification is a performance specification and certification programme for internal power supply units (PSUs), which is recognized by ENERGY STAR® and the European Union (EU) and well known among PSU manufacturers. It provides six levels of certification from standard to titanium for internal power supplies at increasing levels of energy efficiency. + +There are currently five categories for certifications including 115V internal desktop, 230V EU internal desktop, 115V industrial, 230V internal AC and 380V internal DC data centre power supplies. The performance specification requires power supplies in computers and servers to be 80% energy efficient or greater at 20%, 50% and 100% of rated load with a true power factor of 0.9 or higher. + +The following table gives energy efficiency and power factor in 80 PLUS certification. + +**Table I.1 – Energy efficiency and power factor in 80 PLUS certification** + +| 80 PLUS certification | % of rated load | 80 PLUS | Bronze | Silver | Gold | Platinum | Titanium | +|--------------------------------|------------------------|----------------------|----------------------|----------------------|----------------------|----------------------|----------------------| +| 115V internal non-redundant | 10% | - | - | - | - | - | 90% | +| | 20% | 80% | 82% | 85% | 87% | 90% | 92%, PFC $\geq 0.95$ | +| | 50% | 80% | 85%, PFC $\geq 0.90$ | 88%, PFC $\geq 0.90$ | 90%, PFC $\geq 0.90$ | 92%, PFC $\geq 0.95$ | 94% | +| | 100% | 80%, PFC $\geq 0.90$ | 82% | 85% | 87% | 89% | 90% | +| 115V industrial | 10% | - | - | 80% | 82% | 85% | - | +| | 25% | | | 85%, PFC $\geq 0.90$ | 87%, PFC $\geq 0.90$ | 90%, PFC $\geq 0.95$ | | +| | 50% | | | 88% | 90% | 92% | | +| | 100% | | | 85% | 87% | 90% | | +| 230V EU internal non-redundant | 10% | - | - | - | - | - | 90% | +| | 20% | 82% | 85% | 87% | 90% | 92% | 94%, PFC $\geq 0.95$ | +| | 50% | 85%, PFC $\geq 0.90$ | 88%, PFC $\geq 0.90$ | 90%, PFC $\geq 0.90$ | 92%, PFC $\geq 0.90$ | 94%, PFC $\geq 0.95$ | 96% | +| | 100% | 82% | 85% | 87% | 89% | 90% | 91% | +| 230V internal redundant | 10% | - | - | - | - | - | 90% | +| | 20% | | 81% | 85% | 88% | 90% | 94%, PFC $\geq 0.95$ | +| | 50% | | 85%, PFC $\geq 0.90$ | 89%, PFC $\geq 0.90$ | 92%, PFC $\geq 0.90$ | 94%, PFC $\geq 0.95$ | 96% | +| | 100% | | 81% | 85% | 88% | 91% | 91% | +| | 10% | - | 80% | 82% | 85% | 88% | 90% | + +**Table I.1 – Energy efficiency and power factor in 80 PLUS certification** + +| 80 PLUS certification | % of rated load | 80 PLUS | Bronze | Silver | Gold | Platinum | Titanium | +|------------------------------|------------------------|----------------|---------------|---------------|-------------|-----------------|-----------------| +| 380V DC internal redundant | 20% | | 82% | 85% | 88% | 90% | 94% | +| | 50% | | 85% | 89% | 92% | 94% | 96% | +| | 100% | | 82% | 85% | 88% | 91% | 91% | + +### I.2 Ecodesign requirements of the European Union + +Ecodesign is a new rule set by the European Union that aims to gradually improve the energy efficiency of products. The standard covers all energy consuming products in the household, commercial and industrial sectors. The purpose of ecodesign is to achieve the overall goal of low carbon, efficient, and sustainable development of the European Union by eliminating the worst performing products in the market. + +From 1 March 2020, for servers and online data storage products, with the exception of direct current servers and direct current data storage products, the PSU efficiency at 10%, 20%, 50% and 100% of the rated load level and the power factor at 50% of the rated load level shall not be less than the values reported in the following table. + +**Table I.2 – Minimum PSU efficiency and power factor requirements from 1 March 2020** + +| | Minimum PSU efficiency | | | | Minimum power factor | | +|---------------|-------------------------------|------------|------------|------------|-----------------------------|------------| +| | % of rated load | 10% | 20% | 50% | 100% | 50% | +| Multi output | | - | 88% | 92% | 88% | 0.90 | +| Single output | | - | 90% | 94% | 91% | 0.95 | + +From 1 January 2023, for servers and online data storage products, with the exception of direct current servers and direct current data storage products, the PSU efficiency at 10%, 20%, 50% and 100% of the rated load level and the power factor at 50% of the rated load level shall not be less than the values reported in the following table. + +**Table I.3 – Minimum PSU efficiency and power factor requirements from 1 March 2023** + +| | Minimum PSU efficiency | | | | Minimum power factor | | +|---------------|-------------------------------|------------|------------|------------|-----------------------------|------------| +| | % of rated load | 10% | 20% | 50% | 100% | 50% | +| Multi output | | - | 90% | 94% | 91% | 0.95 | +| Single output | | 90% | 94% | 96% | 91% | 0.95 | + +### I.3 Procurement requirements of the People's Republic of (China) + +In order to promote the green and low-carbon development of the digital industry and accelerate the green transformation of data centres, departments of China jointly formulated and released the "Green data centre government procurement demand standards (trial)" document in March 2023, which was implemented from 1 June, 2023. + +The following table gives the energy efficiency and power factor of the PSU in this Recommendation. + +**Table I.4 – Procurement requirements of China** + +| % of rated load | 20% | 50% | 100% | +|------------------------|-------------|-------------|-------------| +| Energy efficiency | 90% | 94% | 91% | +| Power factor | $\geq 0.95$ | $\geq 0.95$ | $\geq 0.95$ | + +### I.4 Certification requirements of China + +CQC3178-2021 "Energy efficiency grades certification criteria for internal power supply" is a certification service jointly developed and launched by the China quality certification center (CQC), equipment manufacturers and Internet manufacturers. This business is applicable to embedded power supply of information technology equipment, telecommunication equipment, audio and video equipment and industrial equipment, aiming to promote the development of the power industry towards the direction of green energy saving. + +The energy efficiency classification certification of embedded power supply is divided into seven levels, among which level I is the lowest level and level VII is the highest level. + +**Table I.5 – Certification requirements of China** + +| 115V internal non-redundant | | | | | | +|-----------------------------|-----------------|-----------------|------|------|------| +| EE classification | Technical index | % of rated load | | | | +| | | 10% | 20% | 50% | 100% | +| Level I | EE | - | 81% | 84% | 80% | +| | PF | - | 0.80 | 0.85 | 0.90 | +| Level II | EE | - | 85% | 88% | 85% | +| | PF | - | 0.80 | 0.90 | 0.95 | +| Level III | EE | - | 88% | 90% | 87% | +| | PF | - | 0.80 | 0.90 | 0.95 | +| Level IV | EE | 85% | 90% | 92% | 89% | +| | PF | 0.80 | 0.85 | 0.95 | 0.95 | +| Level V | EE | 88% | 91% | 93% | 90% | +| | PF | 0.80 | 0.90 | 0.95 | 0.96 | +| Level VI | EE | 90% | 92% | 94% | 91% | +| | PF | 0.80 | 0.95 | 0.95 | 0.98 | +| 220V internal non-redundant | | | | | | +| EE classification | Technical index | % of rated load | | | | +| | | 10% | 20% | 50% | 100% | +| Level I | EE | - | 83% | 86% | 82% | +| | PF | - | 0.80 | 0.90 | 0.90 | +| Level II | EE | - | 87% | 90% | 87% | +| | PF | - | 0.80 | 0.90 | 0.95 | +| Level III | EE | - | 90% | 92% | 89% | +| | PF | - | 0.80 | 0.90 | 0.95 | +| Level IV | EE | 87% | 92% | 94% | 91% | +| | PF | 0.80 | 0.85 | 0.95 | 0.95 | +| Level V | EE | 89% | 93% | 95% | 91% | + +**Table I.5 – Certification requirements of China** + +| | | | | | | +|-----------------------------------------------|-----------------|-----------------|------|------|------| +| | PF | 0.80 | 0.90 | 0.95 | 0.96 | +| Level VI | EE | 91% | 94% | 96% | 92% | +| | PF | 0.80 | 0.95 | 0.95 | 0.98 | +| 220V internal redundant (low voltage output) | | | | | | +| EE classification | Technical index | % of rated load | | | | +| | | 10% | 20% | 50% | 100% | +| Level II | EE | - | 85% | 89% | 85% | +| | PF | - | 0.80 | 0.92 | 0.95 | +| Level III | EE | - | 88% | 92% | 90% | +| | PF | - | 0.80 | 0.92 | 0.98 | +| Level IV | EE | 87% | 91% | 94% | 91% | +| | PF | 0.80 | 0.92 | 0.98 | 0.99 | +| Level V | EE | 90% | 94% | 94% | 91% | +| | PF | 0.90 | 0.95 | 0.98 | 0.99 | +| Level VI | EE | 91% | 95% | 96% | 92% | +| | PF | 0.90 | 0.96 | 0.98 | 0.99 | +| Level VII | EE | 92% | 96% | 97% | 93% | +| | PF | 0.90 | 0.96 | 0.98 | 0.99 | +| 220V internal redundant (high voltage output) | | | | | | +| EE classification | Technical index | % of rated load | | | | +| | | 10% | 20% | 50% | 100% | +| Level IV | EE | 88% | 91% | 94% | 91% | +| | PF | 0.80 | 0.92 | 0.98 | 0.99 | +| Level V | EE | 91% | 94% | 96% | 93% | +| | PF | 0.90 | 0.95 | 0.98 | 0.99 | +| Level VI | EE | 92% | 96% | 98% | 96% | +| | PF | 0.90 | 0.96 | 0.98 | 0.99 | +| Level VII | EE | 93% | 97% | 99% | 97% | +| | PF | 0.90 | 0.96 | 0.98 | 0.99 | + +# Appendix II + +## Example of PSU for server testing + +(This appendix does not form an integral part of this Recommendation.) + +### II.1 Test items + +The test items of the PSU with AC input for the server are shown in Table II.1. + +**Table II.1 – Test item list** + +| Number | Test item | +|--------|--------------------------------------------------------| +| 1 | Input voltage range | +| 2 | No-load power consumption | +| 3 | Energy efficiency | +| 4 | Input rated frequency and frequency fluctuation range | +| 5 | Power factor of different rated load | +| 6 | Total harmonic distortion of input voltage and current | +| 7 | Load distribution management | + +### II.2 Test samples and data + +In order to better understand the technical level of PSUs on the market, these test samples of PSUs for this test are provided by eight mainstream server manufacturers. They can represent the technical level of most PSUs on the market. The input voltage of PSU test samples is AC 220V and the rated frequency is 50 Hz. + +The specific test results are shown in Table II.2 to Table II.6. + +#### II.2.1 Test on input voltage range, input rated frequency and frequency fluctuation tolerance + +**Table II.2 – Test results** + +| Test item | Input voltage range (V) | Input rated frequency (Hz) | Frequency fluctuation tolerance (Hz) | +|-----------|-------------------------|----------------------------|--------------------------------------| +| Sample A | 176~264 | 50 | 45~55 | +| Sample B | 176~264 | 50 | 45~55 | +| Sample C | 176~264 | 50 | 45~55 | +| Sample D | 176~264 | 50 | 45~55 | +| Sample E | 176~264 | 50 | 45~55 | +| Sample F | 176~264 | 50 | 45~55 | +| Sample G | 176~264 | 50 | 45~55 | +| Sample H | 176~264 | 50 | 45~55 | + +It can be seen that under the condition of input voltage range, input rated frequency and frequency fluctuation tolerance from Table II.2 respectively, all the PSU test samples can work normally. + +#### II.2.2 Test on the power factor of different rated load + +Table II.3 – Test results + +| Test item | Power factor of % rated load | | | | | | +|-----------|------------------------------|-------|-------|-------|-------|-------| +| | 100% | 50% | 40% | 30% | 20% | 10% | +| Sample A | 0.999 | 0.995 | 0.994 | 0.990 | 0.984 | 0.963 | +| Sample B | 0.996 | 0.992 | 0.989 | 0.983 | 0.974 | 0.944 | +| Sample C | 0.999 | 0.996 | 0.994 | 0.989 | 0.978 | 0.932 | +| Sample D | 0.999 | 0.995 | 0.992 | 0.986 | 0.978 | 0.935 | +| Sample E | 0.999 | 0.994 | 0.990 | 0.990 | 0.984 | 0.961 | +| Sample F | 0.999 | 0.996 | 0.994 | 0.990 | 0.983 | 0.947 | +| Sample G | 1 | 0.997 | 0.994 | 0.990 | 0.992 | 0.962 | +| Sample H | 0.999 | 0.988 | 0.991 | 0.994 | 0.994 | 0.925 | + +![Bar chart titled 'Comparison with standard value' showing power factor values for 100%, 50%, and 20% load rates. The y-axis ranges from 0.94 to 1.02. The x-axis shows three groups of bars for 100% load rate, 50% load rate, and 20% load rate. Each group contains 9 bars: Standard value (blue), Sample A (orange), Sample B (grey), Sample C (yellow), Sample D (dark blue), Sample E (green), Sample F (dark green), Sample G (brown), and Sample H (dark grey). The standard values are 0.99 for 100%, 0.98 for 50%, and 0.96 for 20%.](ebce355620876e10f907f8b71926c112_img.jpg) + +| Load Rate | Standard value | Sample A | Sample B | Sample C | Sample D | Sample E | Sample F | Sample G | Sample H | +|-----------|----------------|----------|----------|----------|----------|----------|----------|----------|----------| +| 100 % | 0.99 | 0.999 | 0.996 | 0.999 | 0.999 | 0.999 | 0.999 | 1.000 | 0.999 | +| 50 % | 0.98 | 0.995 | 0.992 | 0.996 | 0.995 | 0.994 | 0.996 | 0.997 | 0.988 | +| 20 % | 0.96 | 0.984 | 0.974 | 0.978 | 0.978 | 0.984 | 0.983 | 0.992 | 0.994 | + +Bar chart titled 'Comparison with standard value' showing power factor values for 100%, 50%, and 20% load rates. The y-axis ranges from 0.94 to 1.02. The x-axis shows three groups of bars for 100% load rate, 50% load rate, and 20% load rate. Each group contains 9 bars: Standard value (blue), Sample A (orange), Sample B (grey), Sample C (yellow), Sample D (dark blue), Sample E (green), Sample F (dark green), Sample G (brown), and Sample H (dark grey). The standard values are 0.99 for 100%, 0.98 for 50%, and 0.96 for 20%. + +L.1241(23) + +Figure II.1 – Comparison with standard value of power factor of different rated load + +The power factor of PSU test samples is 100%, 50%, 40%, 30%, 20%, and 10% rated load respectively. From the test results, at a 100% load rate, the highest value of the power factor is 1, and the lowest value is 0.996. At 50% load rate, the highest value of power factor is 0.997, and the lowest value is 0.988. At 20% load rate, the highest value of power factor is 0.994, and the lowest value is 0.974. + +Comparing the test results with the highest requirements of CQC3178-2021 for power factor in Appendix I, it can be seen that all PSU test samples are higher than the requirements. + +#### II.2.3 Test on total harmonic distortion (THD) of voltage and current + +Table II.4 – Test results + +| Test item | Total harmonic distortion of input voltage and current of different rated load | | | | | | | | +|-----------|--------------------------------------------------------------------------------|---------|------------------|--------|--------|--------|--------|--------| +| | THD u | | THD i | | | | | | +| | 100% | No-load | 100% | 50% | 40% | 30% | 20% | 10% | +| Sample A | 0.83% | 0.79% | 4.15% | 7.11% | 8.19% | 9.91% | 11.75% | 15.05% | +| Sample B | 0.86% | 0.79% | 7.93% | 10.65% | 13.37% | 14.87% | 15.22% | 17.77% | +| Sample C | 0.79% | 0.79% | 2.15% | 3.51% | 6.61% | 9.91% | 14.95% | 21.78% | +| Sample D | 0.83% | 0.79% | 4.58% | 5.32% | 5.42% | 6.01% | 9.13% | 18.96% | +| Sample E | 0.81% | 0.79% | 4.28% | 6.50% | 6.60% | 11.32% | 9.82% | 12.27% | +| Sample F | 0.83% | 0.82% | 4.52% | 6.24% | 6.55% | 7.23% | 8.60% | 11.39% | +| Sample G | 0.79% | 0.79% | 2.43% | 3.94% | 4.47% | 5.38% | 7.22% | 14.46% | +| Sample H | 0.80% | 0.81% | 4.72% | 7.83% | 8.43% | 8.59% | 11.09% | 40.85% | + +![Bar chart titled 'Comparison with standard value' showing the total harmonic distortion (THD) of input voltage for various samples. The y-axis represents percentage from 0% to 6%. The x-axis lists 'Standard value' (5%) and samples A through H. The standard value is a green bar at 5%. Samples A-H are blue bars with values: A (0.83%), B (0.86%), C (0.79%), D (0.83%), E (0.81%), F (0.83%), G (0.79%), H (0.80%). All sample values are significantly lower than the 5% standard.](7f687094e6abe34a9cf491942b296d9a_img.jpg) + +| Item | THD u (%) | +|----------------|----------------------| +| Standard value | 5 | +| Sample A | 0.83 | +| Sample B | 0.86 | +| Sample C | 0.79 | +| Sample D | 0.83 | +| Sample E | 0.81 | +| Sample F | 0.83 | +| Sample G | 0.79 | +| Sample H | 0.80 | + +Bar chart titled 'Comparison with standard value' showing the total harmonic distortion (THD) of input voltage for various samples. The y-axis represents percentage from 0% to 6%. The x-axis lists 'Standard value' (5%) and samples A through H. The standard value is a green bar at 5%. Samples A-H are blue bars with values: A (0.83%), B (0.86%), C (0.79%), D (0.83%), E (0.81%), F (0.83%), G (0.79%), H (0.80%). All sample values are significantly lower than the 5% standard. + +L.1241(23) + +Figure II.2 – Comparison with standard value of total harmonic distortion of input voltage + +The requirement of total harmonic distortion of input voltage should not be greater than 5% in GB/T 14549-1993 of China, which is stricter than the compatibility level specified in [IEC 61000-2-2]. All PSU participants in the test can meet the requirement, with the maximum being 0.83%, and the minimum being 0.79%. + +#### II.2.4 Test on no-load power consumption and EE of different rated load + +Table II.5 – Test results + +| Test item | No-load power consumption(W) | | EE of % rated load | | | | | | +|-----------|------------------------------|--------------------------------|--------------------|--------|--------|--------|--------|--------| +| | Rated power $\leq$ 800W | 800 < rated power $\leq$ 1500W | 100% | 50% | 40% | 30% | 20% | 10% | +| Sample A | 8.014 | | 91.77% | 94.34% | 94.41% | 94.27% | 93.84% | 90.78% | +| Sample B | 4.033 | | 93.75% | 94.68% | 94.32% | 93.44% | 92.28% | 88.73% | +| Sample C | 3.864 | | 93.18% | 94.37% | 94.56% | 93.93% | 91.86% | 87.02% | +| Sample D | 2.760 | | 92.55% | 94.43% | 94.87% | 94.61% | 93.57% | 89.66% | +| Sample E | 4.100 | | 93.38% | 94.68% | 94.60% | 94.15% | 93.95% | 91.7% | +| Sample F | | 9.843 | 93.26% | 95.23% | 96.01% | 95.89% | 95.78% | 92.35% | +| Sample G | 5.085 | | 93.63% | 95.05% | 95.10% | 95.15% | 94.24% | 90.99% | +| Sample H | 9.246 | | 92.66% | 94.14% | 94.06% | 93.58% | 92.70% | 87.79% | + +![Bar chart titled 'Comparison with standard value' showing no-load power consumption for eight samples. The x-axis is divided into two groups: 'Rated power ≤ 800 W' and '800 < Rated power ≤ 1500 W'. The y-axis represents power in Watts, ranging from 0 to 16. A green bar for 'Level 1' is at 8W. Sample A is at 8.014W, Sample B at 4.033W, Sample C at 3.864W, Sample D at 2.760W, Sample E at 4.100W, Sample F at 9.843W, Sample G at 5.085W, and Sample H at 9.246W. The chart shows that most samples are below the 8W Level 1 standard, except for Sample F which is above it.](a289b64f80c6df506c0c55d553fc4496_img.jpg) + +| Category | Item | Power (W) | +|---------------------------------|----------|-----------| +| Rated power $\leq$ 800 W | Level 1 | 8 | +| | Sample A | 8.014 | +| | Sample B | 4.033 | +| | Sample C | 3.864 | +| | Sample D | 2.760 | +| | Sample E | 4.100 | +| | Sample G | 5.085 | +| | Sample H | 9.246 | +| 800 < Rated power $\leq$ 1500 W | Level 1 | 15 | +| Sample F | 9.843 | | + +Bar chart titled 'Comparison with standard value' showing no-load power consumption for eight samples. The x-axis is divided into two groups: 'Rated power ≤ 800 W' and '800 < Rated power ≤ 1500 W'. The y-axis represents power in Watts, ranging from 0 to 16. A green bar for 'Level 1' is at 8W. Sample A is at 8.014W, Sample B at 4.033W, Sample C at 3.864W, Sample D at 2.760W, Sample E at 4.100W, Sample F at 9.843W, Sample G at 5.085W, and Sample H at 9.246W. The chart shows that most samples are below the 8W Level 1 standard, except for Sample F which is above it. + +L.1241(23) + +Figure II.3 – Comparison with standard value of no-load power consumption + +Most of the eight PSU test samples participating in the test can meet the requirements of 1% of rated power for no-load power consumption. For PSU with rated power $\leq$ 800 W, the maximum of no-load power consumption is 9.246 W and the minimum is 2.760 W, and for 800 < rated power $\leq$ 1500 W, the no-load power consumption is 9.843 W. + +![Bar chart titled 'Comparison with standard value' showing energy efficiency (EE) percentages for various PSU samples (A-H) and standards (CQC, EU, Platinum) across three load rates: 100%, 50%, and 20%. The y-axis ranges from 87% to 97%.](9ce50bc10864dc86e1cdee4be08f1897_img.jpg) + +**Comparison with standard value** + +| Load Rate | CQC | EU | Platinum | Sample A | Sample B | Sample C | Sample D | Sample E | Sample F | Sample G | Sample H | +|-----------|------|------|----------|----------|----------|----------|----------|----------|----------|----------|----------| +| 100 % | 92 % | 91 % | 90 % | 93 % | 94 % | 93 % | 92 % | 93 % | 93 % | 94 % | 92 % | +| 50 % | 96 % | 96 % | 94 % | 94 % | 95 % | 94 % | 94 % | 95 % | 95 % | 96 % | 94 % | +| 20 % | 94 % | 94 % | 92 % | 94 % | 92 % | 92 % | 94 % | 94 % | 96 % | 94 % | 92 % | + +Bar chart titled 'Comparison with standard value' showing energy efficiency (EE) percentages for various PSU samples (A-H) and standards (CQC, EU, Platinum) across three load rates: 100%, 50%, and 20%. The y-axis ranges from 87% to 97%. + +L.1241(23) + +**Figure II.4 – Comparison with a standard value of EE of different rated load** + +Compared with the energy efficiency (EE) requirements in Appendix I, it can be seen that among the eight PSU samples participating in the test, all the samples can meet the requirements of platinum level in 80 PLUS with 100% and 50% load rate. With a 20% load rate, only one sample cannot meet the platinum level. Although it can be seen from comparative analysis that the requirements of CQC3178-2021 and EU ecodesign 2023 are higher than the test results, it should be noted that these two documents were released a few years later than the test results, and the technical level of PSU has also improved in these years. + +#### II.2.5 Test on load distribution management + +**Table II.6 – Test results** + +| Test item | Load distribution management: load sharing mode | | | | +|-----------|-------------------------------------------------|-------|-------------------|-------| +| | The imbalance of output current sharing | | | | +| | of 100% rated load | | of 50% rated load | | +| Sample A | – | – | – | – | +| Sample B | –1.64% | 1.64% | –0.98% | 0.98% | +| Sample C | –0.34% | 0.34% | –0.59% | 0.59% | +| Sample D | –0.12% | 0.12% | –0.01% | 0.01% | +| Sample E | –1.64% | 1.64% | –0.30% | 0.30% | +| Sample F | –0.56% | 0.56% | –0.21% | 0.21% | +| Sample G | –3.41% | 3.41% | –1.70% | 1.70% | +| Sample H | –0.31% | 0.31% | –0.08% | 0.08% | + +# Bibliography + +- [b-ITU-T L.1330] Recommendation ITU-T L.1330 (2015), *Energy efficiency measurement and metrics for telecommunication networks.* +- [b-ITU-T L.1350] Recommendation ITU-T L.1350 (2016), *Energy efficiency metrics of a base station site.* + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1302-201511-I_PDF-E/3ad00ce93ad9dea9ee0f47535e5355e6_img.jpg b/marked/L/T-REC-L.1302-201511-I_PDF-E/3ad00ce93ad9dea9ee0f47535e5355e6_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..56b31c262895f6cc3910fefc24817766c1d9b1b1 --- /dev/null +++ b/marked/L/T-REC-L.1302-201511-I_PDF-E/3ad00ce93ad9dea9ee0f47535e5355e6_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:3ee59340e50161f0a2af57a7385488b0f752143f80e1e3a33a791f78a9535955 +size 45826 diff --git a/marked/L/T-REC-L.1302-201511-I_PDF-E/4801720824e4b5e2361a5564f91cfb70_img.jpg 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0000000000000000000000000000000000000000..9a9e80c7a078cb28bae2f39bd7ccc22af345d861 --- /dev/null +++ b/marked/L/T-REC-L.1304-202012-I_PDF-E/raw.md @@ -0,0 +1,321 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.1304** + +(12/2020) + +SERIES L: ENVIRONMENT AND ICTS, CLIMATE +CHANGE, E-WASTE, ENERGY EFFICIENCY; +CONSTRUCTION, INSTALLATION AND PROTECTION +OF CABLES AND OTHER ELEMENTS OF OUTSIDE +PLANT + +# --- **Procurement criteria for sustainable data centres** + +Recommendation ITU-T L.1304 + +## ITU-T L-SERIES RECOMMENDATIONS + +## **ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT** + +### **OPTICAL FIBRE CABLES** + +| | | +|-------------------------------------|-------------| +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | + +### **OPTICAL INFRASTRUCTURES** + +| | | +|--------------------------------------------------------|-------------| +| Infrastructure including node elements (except cables) | L.200-L.249 | +| General aspects and network design | L.250-L.299 | + +## **MAINTENANCE AND OPERATION** + +| | | +|-------------------------------------------------|-------------| +| Optical fibre cable maintenance | L.300-L.329 | +| Infrastructure maintenance | L.330-L.349 | +| Operation support and infrastructure management | L.350-L.379 | +| Disaster management | L.380-L.399 | + +### **PASSIVE OPTICAL DEVICES** + +| | | +|-------------------------|-------------| +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +|-------------------------|-------------| + +### **MARINIZED TERRESTRIAL CABLES** + +| | | +|------------------------------|-------------| +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +|------------------------------|-------------| + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1304 + +# Procurement criteria for sustainable data centres + +## Summary + +Recommendation ITU-T L.1304 aims to support public authorities in purchasing data centres related products, services and items with reduced environmental impacts through establishing a set of procurement criteria. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.1304 | 2020-12-14 | 5 | 11.1002/1000/14565 | + +## Keywords + +Data centre, procurement criteria, sustainability. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2021 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 2 | +| 3.1 Terms defined elsewhere ..... | 2 | +| 3.2 Terms defined in this Recommendation..... | 2 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 2 | +| 6 Defining sustainable/green data centres ..... | 2 | +| 7 Procurement criteria for a sustainable data centre ..... | 3 | +| 7.1 Active equipment selection ..... | 3 | +| 7.2 Data centre facility ..... | 4 | +| 7.3 Data centre operation and maintenance..... | 4 | +| Bibliography..... | 5 | + + + +# Recommendation ITU-T L.1304 + +# Procurement criteria for sustainable data centres + +# 1 Scope + +This Recommendation aims to support public authorities in purchasing data centre related solution while taking in consideration a set of sustainable criteria. + +This Recommendation considers energy efficiency solution for equipment and facilities. Different physical construction solutions are considered. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T L.1023] Recommendation ITU-T L.1023 (2020), *Assessment method for circular scoring*. +- [ITU-T L.1300] Recommendation ITU-T L.1300 (2014), *Best practices for green data centres*. +- [ITU-T L.1305] Recommendation ITU-T L.1305 (2019), *Data centre infrastructure management system based on big data and artificial intelligence technology*. +- [ITU-T L.1310] Recommendation ITU-T L.1310 (2020), *Energy efficiency metrics and measurement methods for telecommunication equipment*. +- [ITU-T L.1381] Recommendation ITU-T L.1381 (2020), *Smart energy solutions for data centres*. +- [ITU-T L.1382] Recommendation ITU-T L.1382 (2020), *Smart energy solution for telecommunication rooms*. +- [ITU-T L.1410] Recommendation ITU-T L.1410 (2014), *Methodology for environmental life cycle assessments of information and communication technology goods, networks and services*. +- [ETSI EN 300 019-1-3] ETSI EN 300 019-1-3 V2.4.1 (2014), *Environmental Engineering (EE); Environmental conditions and environmental tests for telecommunications equipment; Part 1-3: Classification of environmental conditions; Stationary use at weatherprotected locations*. +- [ETSI EN 303 470] ETSI EN 303 470 V1.1.1 (2019), *Environmental Engineering (EE); Energy Efficiency measurement methodology and metrics for servers*. +- [ETSI TS 103 586] ETSI TS 103 586 V1.1.1 (2019), *Environmental Engineering (EE); Liquid cooling solutions for Information and Communication Technology (ICT) infrastructure equipment*. + +| | | +|----------------------|---------------------------------------------------------------------------------------------------------------------------------| +| [ISO/IEC 21836] | ISO/IEC 21836:2020), Information technology – Data centres – Server energy effectiveness metric. | +| [ISO/IEC TS 22237-1] | ISO/IEC TS 22237-1:2018, Information technology – Data centre facilities and infrastructures – Part 1: General concepts. | + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 infrastructure (facility)** [ITU-T L.1302]: Equipment that supports information and communication technology (ICT) equipment, e.g., power delivery components and cooling system components. + +**3.1.2 ICT equipment** [ITU-T L.1302]: Information and communication equipment (e.g., computing, storage and network equipment) used in data centres. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following term: + +**3.2.1 green data centre:** A green or sustainable data centre can be defined as a repository for the storage, management, and dissemination of data in which the mechanical, lighting, electrical and computer systems are designed for maximum energy efficiency and minimum environmental impact. + +## 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +ICT Information and Communication Technology + +IT Information Technology + +UPS Uninterruptible Power Supply + +## 5 Conventions + +None. + +# 6 Defining sustainable/green data centres + +A data centre can be defined and evaluated based on the following criteria: + +- Reliability, +- Availability, +- Environmental impact. + +Taking the above into consideration, this Recommendation focuses on examining the environmental impact of a data centre, which is considered to be the main driving force behind selecting procurement items and solutions that are environmentally friendly. + +The environmental impact of a data centre can be evaluated and defined in multiple ways. A detailed analysis of the environmental impact of an existing data centre can be performed using the methodologies contained in [ITU-T L.1410]. + +However, a full assessment of the environmental impact of a data centre using methodologies like [ITU-T L.1410] can be conducted only when the data centre already exists. This implies that this is not useful as procurement criteria if not as possible criteria for future data centre development, based + +on the assessment of an existing one. Hence there is the need to develop a set of procurement criteria in order to implement sustainable data centre. + +In this Recommendation, a sustainable data centre is defined as a data centre that has taken into consideration the following aspects: + +- the location of the data centre, +- equipment that have achieved a low energy consumption, +- it is designed to reduce its total environmental impact. + +In order to support stakeholders to meet the above criteria this Recommendation aims to set the requirement and provide suggestions for selecting IT equipment, facilities and other components, including the ones for the operational phase. + +# **7 Procurement criteria for a sustainable data centre** + +## **7.1 Active equipment selection** + +Active equipment needs to be selected based on the following criteria: + +- Working temperature, +- Energy efficiency, +- Air flow, +- End of life management. + +### **7.1.1 Working temperature** + +Working temperature is an important parameter for active equipment like server, storage, router transmission equipment. In order to realize a sustainable data centre, those equipment needs to be able to work at higher temperature, like equipment able to work in the temperature range 3.1 of [ETSI EN 300 019-1-3] or similar specification from ASHRAE, with same reliability and lifetime, giving the possibility to set the temperature inside the data centre at a higher temperature, set-point. + +The possibility to have a set point of the information technology (IT) room at a higher temperature allows for the use of less energy consumption cooling technology, as indirect free cooling and in any case reducing the energy need for the cooling of the data centre. + +Active equipment needs to be selected with an operating temperature in line with class 3.1 of [ETSI 300 019-1-3]. Additional information on temperature range is available in [b-ASHRAE] where class A3 is equivalent to class 3.1 of [ETSI EN 300 019-3-1]. + +### **7.1.2 Air flow** + +Air flow of new equipment is another necessary consideration, especially when inserting new equipment into existing structure. + +Equipment in the same rack or corridor needs to have the same air flow direction. The air flow direction is preferably from front to back. + +Guidelines on how to manage equipment with different air flow are available in [b-ETSI TR 102 489]. + +### **7.1.3 Energy efficiency** + +Energy efficiency of equipment also needs to be considered. Currently, there are no standardized reference values for equipment energy consumption. The declared energy efficient of the different equipment shall be measured in line with [ETSI EN 303 470] or [ISO/IEC 21836] for server or [ITU-T L.1310] for telecommunication equipment. + +### **7.1.4 End of life management** + +The end-of-life management of data centre equipment needs to be considered in a sustainable data centre. Equipment that takes circular economy criteria into consideration, like those established in [ITU-T L.1023], is preferred. + +## **7.2 Data centre facility** + +A sustainable data centre needs to take into consideration multiple factors, including the total power consumption of IT equipment, their reliability, and the data centre's location. + +[ITU-T L.1300] has provided a list of data centre best practices that are recommended to be taken into consideration. + +The selection of reliability level, like tier 4 established by Uptime institute or class 4 defined by [ISO/IEC TS 22237-1] has an influence on the environmental impact of data centres. Normally a higher reliability level requires more redundancy in the facilities infrastructure and consequently a minimum increase of the losses in mechanical and electrical distributions. + +Reliability level need be selected taking into consideration the real services that are implemented in the data centres, bearing in mind the different reliability levels for the different rooms according to the classification of the service provided by the data centre. + +In the case that the realization of a new data centre also include the realization of a new building, prefabricate solutions need to be considered as this type of solution reduce the activity in field and reduce the civil and engineering work thus respecting the traditional construction of a building where the generation of pollution and waste are reduced. This is due to the fact that a prefabricated module is made in a controlled factory environment and can make use of all the waste management of industrial activities. + +Cooling innovative solution as indirect free-cooling, as discussed in [ITU-T L.1381], needs to be implemented while taking into consideration the environmental condition of the data centre's location. + +Liquid cooling solutions for information and communication technology (ICT) infrastructure equipment need to be taken into account according to the specifications in [ETSI TS 103 586]. + +Solution implementing the utilization of the heat generated inside the data centre, called waste heat reuse, need be considered in the realization. This can cover the utilization heat generated inside the data centre in other activities like agricultural, building for office or civil house. + +Data centre shall be realized by IT module with containment of hot or cold air. + +The power architecture of a data centre can greatly influence its total energy efficiency. Modular uninterruptible power supply (UPS) needs to be selected to facilitate the increase of the power of the energy equipment, UPS system efficiency shall be > of 96%. + +In case of the need for direct current power for telecommunication equipment, the energy efficiency requirement of [ITU-T L.1382] need be considered. + +Renewable energy solution should also be implemented if the location of the data centre permits. + +## **7.3 Data centre operation and maintenance** + +Operation and maintenance impact are very important to realize a sustainable solution. It is strongly recommended to implement the smart solutions as contained in [ITU-T L. 1305] in order to improve the cooling operation and maintenance process. + +## Bibliography + +- [b-Ashrae] Ashrae Thermal Guidelines for Data Processing Environments, Fourth Edition. +- [b-EU GPP] EU green public procurement criteria for data centres, server rooms and cloud services. +[https://ec.europa.eu/environment/gpp/pdf/20032020\\_EU\\_GPP\\_criteria\\_for\\_data\\_centres\\_server\\_rooms\\_and%20cloud\\_services\\_SWD\\_\(2020\)\\_55\\_final.pdf](https://ec.europa.eu/environment/gpp/pdf/20032020_EU_GPP_criteria_for_data_centres_server_rooms_and%20cloud_services_SWD_(2020)_55_final.pdf) +- [b-ETSI TR 102 489] ETSI TR 102 489 (2004), *Environmental Engineering (EE); European telecommunications standard for equipment practice; Thermal Management Guidance for equipment and its deployment*. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1305-201911-I_PDF-E/007b053fe94a8348f75128a584503fd0_img.jpg b/marked/L/T-REC-L.1305-201911-I_PDF-E/007b053fe94a8348f75128a584503fd0_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..3f5e357a4cc015e5ec69e5cac22a1b414b43b4ba --- /dev/null +++ b/marked/L/T-REC-L.1305-201911-I_PDF-E/007b053fe94a8348f75128a584503fd0_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:d3671443b4e34fbf8a35cc714a724cba2a216904416e520ff5029338e9d06baf +size 33941 diff --git a/marked/L/T-REC-L.1305-201911-I_PDF-E/562f471e8153729557e6a4ee6343c32c_img.jpg b/marked/L/T-REC-L.1305-201911-I_PDF-E/562f471e8153729557e6a4ee6343c32c_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..e7c4440b2a96e727c5082470cb45afbdaac0906c --- /dev/null +++ b/marked/L/T-REC-L.1305-201911-I_PDF-E/562f471e8153729557e6a4ee6343c32c_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:51989ca119e41be069f1aabe9990c16c2ee11945340c9d019e507e8cfe4de8ae +size 89864 diff --git a/marked/L/T-REC-L.1305-201911-I_PDF-E/90ddf538ef276510e2b631f7b96654e6_img.jpg b/marked/L/T-REC-L.1305-201911-I_PDF-E/90ddf538ef276510e2b631f7b96654e6_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..e6c3614c8864df49a3d3c079e6f642b0d6ced276 --- /dev/null +++ b/marked/L/T-REC-L.1305-201911-I_PDF-E/90ddf538ef276510e2b631f7b96654e6_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:2e5ffbe834c76e9f97d17aa1d96f9a80ed57206cc37799ba919a5c22033498cf +size 47753 diff --git a/marked/L/T-REC-L.1305-201911-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg b/marked/L/T-REC-L.1305-201911-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..0988fb4557df2eed55c077264f12eec2495bf7d9 --- /dev/null +++ b/marked/L/T-REC-L.1305-201911-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:69e21a86dbb0820476581334df30a66557fbcfc7ba2d8370303bb311a7e84ddd +size 4098 diff --git a/marked/L/T-REC-L.1305-201911-I_PDF-E/f4fdd410cdb84df81274da55721e56fb_img.jpg b/marked/L/T-REC-L.1305-201911-I_PDF-E/f4fdd410cdb84df81274da55721e56fb_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..bb951b0407ad192a0bf13faaef845460b20f2dec --- /dev/null +++ b/marked/L/T-REC-L.1305-201911-I_PDF-E/f4fdd410cdb84df81274da55721e56fb_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:a5d3c405bde88e4655da6f3331d1e51b2f2b9ca9f9b95fbb6a4d373e133705a9 +size 83388 diff --git a/marked/L/T-REC-L.1311-202507-I_PDF-E/0538daaa5583c23e17db3a12f2281a55_img.jpg b/marked/L/T-REC-L.1311-202507-I_PDF-E/0538daaa5583c23e17db3a12f2281a55_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..c1629394c02f697f60ae954ad36bf274fa8082cb --- /dev/null +++ b/marked/L/T-REC-L.1311-202507-I_PDF-E/0538daaa5583c23e17db3a12f2281a55_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:3763acd7a0ed56aa30f3f90468c1fb0cb54573eb9045bca3eddf8976b4f0f41d +size 7219 diff --git a/marked/L/T-REC-L.1311-202507-I_PDF-E/raw.md b/marked/L/T-REC-L.1311-202507-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..6c0c9b305a9dbc383946fa49bef3e6aee7a0a00c --- /dev/null +++ b/marked/L/T-REC-L.1311-202507-I_PDF-E/raw.md @@ -0,0 +1,782 @@ + + +# Recommendation **ITU-T L.1311 (07/2025)** + +SERIES L: Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant + +Energy efficiency, smart energy and green data centres + +--- + +# **Energy efficiency measurement methodology and metrics for heterogeneous servers** + +![ITU logo](0538daaa5583c23e17db3a12f2281a55_img.jpg) + +The logo of the International Telecommunication Union (ITU), featuring the letters 'ITU' in blue inside a circle with a globe-like design. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +### **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|---------------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| Infrastructure including node elements (except cables) | L.200-L.249 | +| General aspects and network design | L.250-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| Optical fibre cable maintenance | L.300-L.329 | +| Infrastructure maintenance | L.330-L.349 | +| Operation support and infrastructure management | L.350-L.379 | +| Disaster management | L.380-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1311 + +## Energy efficiency measurement methodology and metrics for heterogeneous servers + +## Summary + +Recommendation ITU-T L.1311 contains an energy efficiency methodology definition and metrics definition for heterogeneous servers. + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.1311 | 2025-07-29 | 5 | 11.1002/1000/16414 | + +## Keywords + +Energy efficiency, heterogeneous, power, server. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, and information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2025 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|---------------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation ..... | 3 | +| 4 Abbreviations and acronyms ..... | 3 | +| 5 Conventions ..... | 4 | +| 6 Heterogeneous server product categories and representative product configurations.. | 4 | +| 6.1 General ..... | 4 | +| 6.2 Applications and metric applicability ..... | 5 | +| 6.3 Product categories ..... | 5 | +| 6.4 Product family configuration..... | 6 | +| 7 Metrics ..... | 7 | +| 7.1 Worklets ..... | 7 | +| 7.2 Formulae..... | 7 | +| 8 Test set-up..... | 9 | +| 8.1 General ..... | 9 | +| 8.2 Environmental conditions..... | 9 | +| 8.3 Temperature sensor ..... | 9 | +| 8.4 Input power..... | 9 | +| 8.5 Power requirements ..... | 9 | +| 8.6 Energy consumption analyser..... | 9 | +| 8.7 Test tool..... | 10 | +| 8.8 Controller system..... | 10 | +| 9 Equipment under test ..... | 10 | +| 9.1 Configuration..... | 10 | +| 9.2 Test procedure ..... | 12 | +| 10 Measurement..... | 13 | +| 10.1 Measurement for active state ..... | 13 | +| 10.2 Re-verification and audits..... | 14 | +| 10.3 Measurement for power supply ..... | 14 | +| 11 Measurement report ..... | 16 | +| Bibliography..... | 17 | + +## Introduction + +The number of computer servers and data centres have increased rapidly and they play a central role in digital services. With the development of artificial intelligence (AI), heterogeneous servers equipped with more than one type of processor (central processing unit (CPU), graphical processing units (GPU), field programmable gate array (FPGA), application-specific integrated circuit (ASIC), etc.) play an increasingly important role and take a growing market share in the computing industry. Heterogeneous servers gain extra performance by adding dissimilar coprocessors, usually incorporating specialized processing capabilities to handle particular tasks [b-Shan]. Categories of heterogeneous servers include CPU+GPU server, CPU+FPGA server and CPU+ASIC server. The most popular heterogeneous server type is the CPU+GPU server, which is commonly used to accelerate the training process of deep learning by parallel computing. + +For heterogeneous servers, the better performance the higher the energy consumption. There is a trade-off between the performance and energy consumption for high performance heterogeneous servers. Energy efficiency (EE) that scales server performance and energy consumption is one of the critical factors for the server operation and maintenance. [b-ETSI EN 303 470] specifies the metric and method for EE assessment of general servers. However, there is currently no standard for EE assessment of heterogeneous servers. + +This Recommendation specifies a metric for the assessment of EE of heterogeneous servers using reliable, accurate and reproducible measurement methods, which take into account the recognized state-of-the-art. The Recommendation formalizes the tools, conditions and calculations used to generate a single figure of merit of a single heterogeneous server representing its relative EE and power consumption. The single figure EE metric is targeted for use as a tool in the selection process of heterogeneous servers to be provisioned. + +For comparisons, evaluations should be conducted across similar heterogeneous server types or categories. The EE metric is targeted for identifying energy saving servers by differentiating the ability of heterogeneous servers to be provisioned for the mainstream market. This Recommendation does not prescribe the levels or values for acceptance but prescribes a method of evaluation which EE programs could use to establish such criteria. + +As there are many operational deployments of heterogeneous servers resulting in a range of specialized equipment and configurations for a single heterogeneous server product, an EE metric that evaluates provisioning impacts to general-purpose operations may not be applicable. ICT equipment, and servers in particular, are generally customized and commissioned on site for deployment. As with most ICT equipment, new technologies are regularly introduced, which may require product level customization or an industry wide tool upgrade to more appropriately represent the EE of the heterogeneous servers. + +This Recommendation categorizes heterogeneous servers to address applicability, configuration groupings to represent a diversity of heterogeneous servers to address the broad range of custom configurations, as well as a tool revision control to ensure comparability and consistency of the resulting metric value. + +The content of this Recommendation was developed jointly by ETSI TC EE and ITU-T Study Group 5 and published by ITU and ETSI as this Recommendation, ITU-T L.1311, and ETSI Standard [b-ETSI ES 204 083] (V1.1.1) respectively; these are technically equivalent. + +# Recommendation ITU-T L.1311 + +## Energy efficiency measurement methodology and metrics for heterogeneous servers + +# 1 Scope + +This Recommendation is based upon a benchmark for a server energy efficiency (EE) tool for general and heterogeneous servers. + +This Recommendation specifies: + +- 1) Test conditions and product configuration for the assessment of the EE of heterogeneous servers using reliable, accurate and reproducible measurement methods; +- 2) An EE metric to support procurement requirements; +- 3) Requirements for equipment to perform the measurements and analysis; +- 4) Requirements for the measurement process; +- 5) Requirements for the management of the EE metric calculation; +- 6) Operation or run rules to configure, execute and monitor the testing; +- 7) Documentation and reporting requirements. + +The metrics and methods apply to heterogeneous servers with various configurations, including type and count of APAs, CPU, memory, storage and any other add-on hardware expected to be present when deployed. + +NOTE – Products whose feature set and intended operation are not addressed by active mode testing parameters are excluded from this evaluation method. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[IEC 62623] IEC 62623 (2022), *Desktop and notebook computers – Measurement of energy consumption*. + +[IEEE 802.3] IEEE 802.3 (2022), *IEEE Standard for Ethernet*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 active state** [b-ETSI EN 303 470]: Operational state of a computer server (as opposed to the idle state) in which the computer server is carrying out work in response to prior or concurrent external requests (e.g., instruction over the network). + +NOTE – The work includes, but is not restricted to, active processing and data seeking/retrieval from memory, cache, or internal/external storage while awaiting further input over the network. + +**3.1.2 auxiliary processing accelerator (APA)** [b-ETSI EN 303 470]: Additional compute device installed in the computer server that handles parallelized workloads. + +NOTE 1 – This includes, but is not limited to, Graphical Processing Units (GPUs) or Field Programmable Gate Array chips which can be installed in a server either on Graphics or Extension add-in cards installed in general-purpose add-in expansion slots (e.g., GPUs, CPU accelerators, etc. installed in a PCI slot) or directly attached to a server component such as the motherboard. + +NOTE 2 – There are two specific types of APAs used in servers: + +- a) Expansion APA: An APA that is on an add-in card installed in an add-in expansion slot (e.g., GPUs, CPU accelerators, etc. installed in a PCI slot). An expansion APA add-in card may include one or more APAs. +- b) Integrated APA: An APA that is integrated into the motherboard or CPU package or an expansion APA that has part of its subsystem, such as switches, included in the non-APA server configuration that would be used to run the energy efficiency test (SERTTM suite). + +**3.1.3 blade chassis** [b-EU 2019/424]: Enclosure that contains shared resources for the operation of blade servers, blade storage, and other blade form-factor devices. Shared resources provided by a blade chassis may include power supply units, data storage, and hardware for direct current power distribution, thermal management, system management, and network services. + +NOTE – Shared resources provided by a chassis include, but are not restricted to, power supplies, data storage and hardware for DC power distribution, thermal management, system management and network services. + +**3.1.4 blade server** [b-ETSI EN 303 470]: Computer server, designed for use in a blade chassis, that is a high-density device and functions as an independent computer server and includes at least one processor and system memory, which is dependent upon shared blade chassis resources (e.g., power supplies, cooling) for operation. + +NOTE – A processor or memory module that is intended to scale up a standalone server is not considered a blade server. + +**3.1.5 blade system** [b-ETSI EN 303 470]: Blade chassis and one or more removable blade servers and/or other units (e.g., blade storage, blade networking equipment) which provide a scalable means for combining multiple blade server or storage units in a single enclosure. + +NOTE – A blade system is designed to allow service technicians to easily add or replace (hot-swap) blades in the field. + +**3.1.6 controller system** [b-ETSI EN 303 470]: Computer or computer server that manages a benchmark evaluation process. + +**3.1.7 deployed power** [b-ETSI EN 303 470]: Average power level of the utilization applicable to the total number of servers provisioned to meet an aggregate peak load. + +**3.1.8 hypervisor** [b-ETSI EN 303 470]: Supervisory system level software that establishes and manages a virtualized environment which enables multiple operating systems to run on a single physical system at the same time. + +**3.1.9 pedestal server** [b-ETSI EN 303 470]: Self-contained computer server that is designed with power supply units, cooling, input/output devices, and other resources necessary for stand-alone operation within a frame similar to that of a tower client computer. + +**3.1.10 rack-mounted server** [b-ETSI EN 303 470]: Computer server that is designed for deployment in a standard 19-inch ICT equipment rack as defined by [b-CLC EN 60297] or [b-ETSI EN 300 119]. + +NOTE – For the purposes of the present Recommendation, a blade server is considered under a separate product category and is excluded from the rack-mounted product category. + +**3.1.11 server** [b-EU 2019/424]: A computing product that provides services and manages networked resources for client devices, such as desktop computers, notebook computers, desktop thin clients, internet protocol telephones, smartphones, tablets, tele-communication, automated systems + +or other servers, primarily accessed via network connections, and not through direct user input devices, such as a keyboard or a mouse and with the following characteristics: + +- a) it is designed to support server operating systems (OS) and/or hypervisors, and targeted to run user-installed enterprise applications; +- b) it supports error-correcting code and/or buffered memory (including both buffered dual in-line memory modules and buffered on board configurations); +- c) all processors have access to shared system memory and are independently visible to a single OS or hypervisor. + +**3.1.12 single-wide blade server** [b-ETSI EN 303 470]: Blade server requiring the width of a standard blade server bay. + +**3.1.13 worklet:** Synthetic software routine, using real application functions focused on a particular type of computing activity, which stresses a particular characteristic of the system. + +NOTE 1 – A floating point and integer performance stress code is an example of a central processing unit (CPU) worklet. + +NOTE 2 – An image classification training code is an example of an artificial intelligence (AI) worklet. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 application-specific integrated circuit (ASIC):** An integrated circuit chip customized for a particular use. + +NOTE 1 – Processor units that are ASICs include, but are not limited to, the following: + +- a) Tensor processing unit (TPU), an AI accelerator ASIC developed specifically for neural network machine learning; +- b) Vision processing unit (VPU), a specific type of AI accelerator, designed to accelerate machine vision tasks; +- c) Neural processing unit (NPU): a specialized processing unit that is designed to accelerate artificial intelligence and machine learning applications, including artificial neural networks and machine vision; +- d) Deep learning processing unit (DPU): a processor designed for deep learning that has the ability to handle large-scale neural networks. + +NOTE 2 – Digital signal processor (DSP) is used in embedded and real-time systems. + +**3.2.2 processor:** A digital circuit that performs operations on some external data source, usually memory or some other data stream. + +NOTE – Processor types include, but are not limited to, central processing unit (CPU), graphics processing unit (GPU), neural processing unit (NPU), tensor processing unit (TPU), deep learning processing unit (DPU), vision processing unit (VPU), etc. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|---------|---------------------------------------------------------| +| AC | Alternating Current | +| APA | Auxiliary Processing Accelerator | +| ASIC | Application-Specific Integrated Circuit | +| BIOS | Basic Input/Output System | +| CENELEC | European Committee for Electrotechnical Standardization | +| CPU | Central Processing Unit | + +| | | +|------|-------------------------------------------| +| DC | direct current | +| DIMM | Dual In-line Memory Module | +| DPU | Deep learning Processing Unit | +| DSP | Digital Signal Processor | +| EE | Energy Efficiency | +| EEE | Energy Efficient Ethernet | +| EUT | Equipment Under Test | +| FPGA | Field Programmable Gate Array | +| GPU | Graphical Processing Unit | +| HDD | Hard Disk Drive | +| I/O | Input/Output | +| ICT | Information and Communication Technology | +| NPU | Neural Processing Unit | +| OS | Operating System | +| PCI | Peripheral Component Interconnect | +| PCIe | Peripheral Component Interconnect express | +| PDU | Power Distribution Unit | +| PSU | Power Supply Unit | +| RMS | Root Mean Square | +| SSD | Solid State Drive | +| TPU | Tensor Processing Unit | +| UPS | Uninterruptable Power Supply | +| VPU | Vision Processing Unit | + +# 5 Conventions + +None. + +# 6 Heterogeneous server product categories and representative product configurations + +## 6.1 General + +Heterogeneous servers are sold in different types and counts of APAs, and configuration types and different groups of heterogeneous servers will have distinct performance capability and power demands. + +Heterogeneous servers are categorized as defined in clause 6.3 by specific configuration parameters to enable the setting of appropriate idle power or active efficiency thresholds and assessment of like products with regards to procurement or market entry requirements. + +To compare or evaluate systems, the evaluation or EE metric shall only be made among similar products. Similar products are grouped into categories. Products of categories not listed shall not be compared using the EE metric of this Recommendation. + +Even though heterogeneous servers are classified in categories by the type of system, each server is customized by its configuration to best match the application for which it is being sold or purchased. As a result, a product is represented by a fixed set of configurations that is decided by the form-factor, category, number or type of APAs and processors, and capacities of memory. For an appropriate evaluation, the category shall be defined. + +## **6.2 Applications and metric applicability** + +Heterogeneous servers are designed to be configurable to different groups of applications. The full configuration, including logical and physical elements, is optimized to deliver the most effective platform for operating those applications. + +The software component of the EE metric is designed to execute typical real world applications and is designed to stress and assess the elements and associated functionality included in the server systems. By stressing the elements in a fashion that replicates real world applications, a process for measuring workload output and its associated power demand is established. + +Changes in application target, technology, configuration or elements will impact the results and applicability of the EE metric. Therefore, it is necessary to establish categories of products that describe the elements of similar products, determine representative configurations and ensure the applicability of the EE metric. + +Categories or comparison groups of heterogeneous servers are formed by a combination of physical characteristics and limitations. The categories are separated based on computer architecture and physical differences that determine a different energy profile unique to that group. The server metric in the present Recommendation may not be applicable to certain categories of systems. + +## **6.3 Product categories** + +### **6.3.1 General requirements** + +For the purposes of the present Recommendation, a heterogeneous server shall meet all of the following criteria: + +- Be marketed and sold as a computer server; +- Be designed for and listed as supporting one or more computer server Operating Systems (OSs) and/or hypervisors; +- Be designed such that all processors have access to shared system memory and are visible to a single OS or hypervisor; +- Be targeted to run user-installed applications typically, but not exclusively, enterprise in nature; +- Be packaged and sold with one or more AC-DC or DC-DC power supplies; +- Provide support for error-correcting code and/or buffered memory (including both buffered dual in-line memory modules (DIMMs) and buffered on board configurations). + +### **6.3.2 Form factors** + +Heterogeneous servers follow the same form factors of general computer servers. Three form factors are considered as defined in clause 3.1: + +- Blade; +- Rack-mounted; +- Pedestal. + +### 6.3.3 Categories + +The heterogeneous server metrics of this Recommendation are applicable to the following product categories as defined and uniquely characterized in clause 3: + +- $X$ CPU + GPU server; +- $X$ CPU + FPGA server; +- $X$ CPU + ASIC server. + +NOTE 1 – $X$ represents the form-factor, $X$ may be blade, rack-mounted or pedestal. + +NOTE 2 – "CPU + APA" means the server is equipped with both CPU and one type of APAs. The type of APA could be GPU, FPGA, ASIC (ASIC could be anyone of the NPU, TPU, DPU, VPU, etc.). + +## 6.4 Product family configuration + +### 6.4.1 General + +A heterogeneous server product family configuration shall: + +- Be from the same model line or machine type; +- Either share the same form-factor or share the same mechanical and electrical designs with only superficial mechanical differences to enable a design to support multiple form-factors; +- Either share processors from a single defined processor/APA series or share processors/APAs that plug into a common socket/connector/port/slot type; +- Have the same number of processors and APAs; +- Be dependent on common power supply unit(s). + +A given product family can have in excess of tens of thousands of possible combinations of components in separate, distinct configurations. This can include many different processor models with differing APA core count, frequency or memory, as well as numerous types of components such as CPU, I/O devices, memory and storage devices. + +For the purposes of defining the configurations of clauses 6.4.2 and 6.4.3, the following apply to both heterogeneous server and general server with APA cards: + +- Calculated APA processor computing capacity (dimensionless) = "the number of APAs" $\times$ "the number of cores per APA" $\times$ "APA frequency (GHz)". + - EXAMPLE: 2 GPUs, each with 10496 cores, with a frequency of 1.7 GHz +$$\text{GPU computing capacity} = 35686.4.$$ +- Calculated APA memory capacity (GB) = "the number of APAs" $\times$ "the APA memory capacity (GB)". + - EXAMPLE: 2 GPUs, GPU memory 24 GB +$$\text{GPU memory capacity} = 48 \text{ GB}.$$ +- Calculated CPU capacity (dimensionless) = "the number of CPUs" $\times$ "the number of cores per CPU" $\times$ "the number of threads per core" $\times$ "CPU frequency (GHz)". + - EXAMPLE: 2 CPUs, each with 4 cores and 2 threads per core, with a frequency of 2.2 GHz +$$\text{CPU capacity} = 35.2.$$ +- Calculated memory capacity (GB) = "the number of CPUs" $\times$ "the number of cores per CPU" $\times$ "the number of threads per core" which is subsequently rounded up to "the number of memory channels" $\times$ "the lowest capacity DIMM available for the product family". + - EXAMPLE: 2 CPUs, each with 4 cores and 2 threads per core + +Memory capacity = 16 GB + +If the product has 4 memory channels and the lowest capacity DIMM is 2 GB, then $8 \times 2$ GB\_DIMMs (assuming 2 slots per channel). + +### 6.4.2 High-end performance configuration + +A high-end performance configuration of a heterogeneous server product family means: + +- An APA processor with the highest product of core count/frequency/memory; +- A CPU processor with the highest product of core count/frequency; +- A memory capacity equal to or greater than 3 times the product of the number of APAs; +- Cores and hardware threads that represents the highest performance product model within the product family. + +### 6.4.3 Low-end performance configuration + +A low-end performance configuration of a heterogeneous server product family means: + +- An APA processor with the lowest product of core count/frequency/memory; +- A CPU processor with the lowest product of core count/frequency; +- A memory capacity that is at least equal to the product of the number of memory channels; +- The lowest capacity DIMM (in GB) offered on the server that represents the lowest performance product model within the server product family. + +# 7 Metrics + +## 7.1 Worklets + +EE testing tools shall report energy consumption, runtime and performance data for: + +- Three AI training worklets, i.e., image classification, image segmentation and natural language processing; + +and correspondingly: + +- Thress AI inference worklets, i.e., image classification, image segmentation and natural language processing. + +The selected training and inference worklets are the most general AI applications. + +For each worklet, data are reported for a set of proportional performance intervals and associated, measured energy consumption and runtime values along with other test measurements. The set of individually measured performance, energy consumption and runtime values with their associated efficiency value is termed "interval data". + +## 7.2 Formulae + +### 7.2.1 General + +The geometric mean function is used to combine the interval data to produce a worklet efficiency score, and the worklet efficiency scores are used to create a workload efficiency metric. Using the geometric mean prevents any single performance, energy consumption, worklet runtime or workload efficiency score from unduly influencing the single metric. + +In order to create a single EE metric for a server, it is necessary to combine the interval efficiency values for all the different worklets in a specific testing scenario using the following general procedure: + +- a) combine the interval efficiency values for the individual worklets using the geometric mean to obtain individual worklet efficiency values for the worklet; + +- b) combine worklet efficiency scores using the geometric mean function by workload type (training or inference) to obtain a workload type value; +- c) combine the workload types using a geometric mean function to obtain a single, total server efficiency value. + +In order to facilitate the deployed power assessment for each heterogeneous server configuration, the performance and energy consumption can be combined using the same process as above: + +The energy efficiency metric is defined as: + +$$Eff_{server} = \text{Exp}(W_{train} \times \ln Eff_{train} + W_{inference} \times \ln Eff_{inference})$$ + +where: + +$W_{train}$ and $W_{inference}$ are the weight factors of AI training worklets and AI inference worklets, respectively; + +and: + +$$Eff_{train} = (\prod_{i=1}^3 Eff_i)^{\frac{1}{3}}$$ + +where: + +$i = 1$ for the normalized interval efficiency of training worklet of image classification; + $i = 2$ for the normalized interval efficiency of training worklet of image segmentation; + $i = 3$ for the normalized interval efficiency of training worklet of natural language processing; + +and: + +$$Eff_{inference} = (\prod_{i=1}^3 Eff_i)^{\frac{1}{3}}$$ + +where: + +$i = 1$ for the normalized interval efficiency of inference worklet of image classification; + $i = 2$ for the normalized interval efficiency of inference worklet of image segmentation; + $i = 3$ for the normalized interval efficiency of inference worklet of natural language processing; + +and: + +$$Eff_i = \frac{Perf_i}{Pwr_i}$$ + +where: + +$Perf_i$ : the normalized interval performance measurements of worklet $i$ ; + +$Pwr_i$ : the measured interval power values of worklet $i$ . + +### 7.2.2 Weightings + +In this Recommendation, the weighting factor of training and inference worklets are defined as follows: + +- $W_{training}$ is the weighting assigned to the CPU worklets = 0.5. +- $W_{inference}$ is the weighting assigned to the Memory worklets = 0.5. + +# **8 Test set-up** + +## **8.1 General** + +A single test set-up shall be used to undertake the measurements to be used to determine the energy efficiency metrics. + +## **8.2 Environmental conditions** + +### **8.2.1 Ambient temperature** + +Ambient temperature shall be $25 \pm 5^\circ\text{C}$ . + +### **8.2.2 Relative humidity** + +Relative humidity shall be between 15% and 80%. + +## **8.3 Temperature sensor** + +The temperature sensor shall: + +- a) Have a temperature measurement accuracy within $\pm 0.5^\circ\text{C}$ when measured no more than 50 mm in front of (upwind of) the main airflow inlet of the equipment under test (EUT); +- b) Have a logging performance of a minimum reading rate of four samples per minute. + +## **8.4 Input power** + +During the test, the input voltage tolerance to the EUT shall be as specified below: + +- a) $\leq 1.0\%$ if the power consumption is $\leq 1\,500\text{ W}$ ; +- b) $\leq 4.0\%$ if the power consumption is $> 1\,500\text{ W}$ . + +For AC input voltages, the frequency tolerance shall be $\leq 1.0\%$ and the total harmonic distortion shall be as specified below: + +- a) $\leq 2.0\%$ if power consumption is $\leq 1\,500\text{ W}$ ; +- b) $\leq 5.0\%$ if power consumption is $> 1\,500\text{ W}$ . + +## **8.5 Power requirements** + +Testing shall be conducted within the following frequency and voltage ranges. + +AC Frequency: $\pm 1\%$ of 50 Hz + +Voltage: $\pm 5\%$ of 220 V, 230 V, 240 V. + +## **8.6 Energy consumption analyser** + +The following requirements apply to the single-phase power analyser. + +The power analyser shall report true root mean square (RMS) power and at least two of the following parameters: voltage, current and power factor. + +The power analyser shall: + +- a) Have a valid calibration certificate or equivalent, to support its use at the time the tests are carried out; +- b) Feature an available current crest factor of 3 or more at its rated range value; +- c) For power analysers that do not specify the current crest factor, the power analyser shall be capable of measuring an amperage spike of at least 3 times the maximum amperage measured during any 1 second sample; + +- d) Have a minimum frequency response of 3.0 kHz; +- e) Have a minimum resolution of: + - 0.01 W for measurement values less than 10 W; + - 0.1 W for measurement values from 10 W to 100 W; and + - 1.0 W for measurement values greater than 100 W. +- f) Have a power measurement accuracy of greater than 99.0%; +- g) Have a logging performance of: + - 1) Minimum reading rate: one set of measurements (power measurement in W) per second; + - 2) Data averaging interval equal to the reading rate. + +The worklet runtime is recorded, including the start and end time. The energy consumption of a worklet is + +$$E_{worklet} = \int_{t_{start}}^{t_{end}} p t dt$$ + +where $t_{start}$ is the start time of the worklet, $t_{end}$ is the end time of the worklet and $p$ is the power. + +## 8.7 Test tool + +A server EE testing tool shall be used to determine the EE of the EUT. + +## 8.8 Controller system + +The controller system shall be capable of the following functions: + +- a) Starting and stopping each segment (phase) of the performance benchmark; +- b) Controlling the workload demands of the performance benchmark; +- c) Starting and stopping data collection from the power analyser so that power and performance data from each phase can be correlated; +- d) Storing log files containing benchmark power and performance information; +- e) Converting raw data into pdf and html format for benchmark reporting, submission and validation; +- f) Collecting and storing environmental data (temperature), if automated for the benchmark. + +The controller system may be a server, a desktop computer or a laptop and shall be used to record input power from the equipment specified in clause 8.6 and temperature data from the equipment specified in clause 8.3. + +The controller system and the EUT shall be connected to each other via one port of an Ethernet network switch. + +# 9 Equipment under test + +## 9.1 Configuration + +The configuration of the EUT shall be as specified in Table 1. + +**Table 1 – Configuration of EUT** + +| Index | Items | Detailed requirements | +|-------|----------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| A) | As-shipped condition | Products shall be tested in their "as-shipped" condition, which includes both hardware revision and system settings, unless otherwise specified in this test method. | + +**Table 1 – Configuration of EUT** + +| Index | Items | Detailed requirements | +|-------|---------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| | | Where relevant, all software options shall be set to their default condition. | +| B) | Measurement location |

All power measurements shall be taken at a point between the AC power source and the EUT.

Uninterruptible power supply (UPS) units shall not be connected between the power meter and the EUT.

The power meter shall remain in place until all the state efficiency power data are fully recorded.

When testing a blade system, power shall be measured at the input of the blade chassis (i.e., at the power supplies that provide chassis distribution power).

| +| C) | Air flow | Purposefully directing air in the vicinity of the measured equipment in a way that would be inconsistent with normal practices at the intended installation location is prohibited. | +| D) | Power supplies |

All power supply units (PSUs) shall be connected and operational.

For EUT with multiple PSUs:

  • All power supplies shall be connected to the AC power source and operational during the test;
  • If necessary, a Power Distribution Unit (PDU) may be used to connect multiple power supplies to a single source (if a PDU is used, any overhead electrical use from the PDU shall be included in the power measurement of the EUT).

For blade servers with half-populated chassis configurations, the power supplies for the unpopulated power domains can be disconnected (see Table 3, D for more information).

| +| E) | Power management and operating system |

The as-shipped operating system or a representative operating system shall be installed. Products that are shipped without OSs shall be tested with any compatible operating system installed.

For all tests, the power management techniques and/or power saving features shall be left as shipped.

Any power management features which require the presence of an operating system (i.e., those that are not explicitly controlled by the basic input output system (BIOS) or management controller) shall be tested using only those power management features enabled by the operating system by default.

| +| F) | Storage |

Products shall be tested for qualification with at least two HDD or two SSD installed. Products that do not include pre-installed drives (HDD or SSD) shall be tested using a storage configuration used in an identical model for sale that does include pre-installed drives.

Products that do not support the installation of drives (HDD or SSD) and instead rely exclusively on external storage solutions (e.g., storage area network) shall be tested using external storage solutions.

| +| F1) | APAs | The EUT shall be tested with extra expansion APAs or add-in cards removed, except for the tested APAs, when measuring the efficiency and server performance in active state | +| F2) | Memory channels | Any EUT with some memory channels unpopulated should be reconfigured so all memory channels have the same DIMMs. | + +**Table 1 – Configuration of EUT** + +| Index | Items | Detailed requirements | +|-------|-------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| G) | Blade system and dual/multinode servers | A blade system or dual/multinode server shall have identical configurations for each node or blade server including all hardware components and software/power management settings. These systems shall also be measured in a way that ensures all power from all tested nodes/blade servers is captured by the power meter during the entire test. | +| H) | Blade chassis | The blade chassis, at a minimum, shall have power, cooling and networking capabilities for all the blade servers. The blade chassis shall be populated as specified in Table 3, D).
All power measurements for blade systems shall be made at the input of the blade chassis. | +| I) | BIOS and EUT system settings | All BIOS settings shall remain as shipped unless otherwise specified in the test method. | +| J) | Input/output (I/O) and network connection | The EUT shall have at least one port connected to an Ethernet network switch. The switch shall be capable of supporting the EUT's highest and lowest rated network speeds. The network connection shall be live during all tests, and, although the link shall be ready and able to transmit packets, no specific traffic is required over the connection during testing.
For the purpose of testing ensure the manufacturer shall offer at least one Ethernet port (using a single add-in card only if no on-board Ethernet support is offered). | +| K) | Energy efficient ethernet (EEE) | Products shipped with support for energy efficient ethernet (compliant with clause 78 of [IEEE 802.3-2022]) shall be connected only to energy efficient ethernet compliant networking equipment during testing. Appropriate measures shall be taken to enable EEE features on both ends of the network link during all tests. | + +## 9.2 Test procedure + +The EUT test configuration shall be in accordance with Table 2. + +**Table 2 – Test configuration of EUT** + +| Index | Detailed requirements | +|-------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| A) | The EUT shall be tested with all processor connectors populated. | +| B) | The EUT shall be installed in a test rack or other static location and shall not be physically moved until testing is complete. | +| C) | For a multi-node system, the power consumption per node of the EUT shall be measured in the fully-populated blade chassis configuration. All multi-node servers installed in the blade chassis shall be identical, sharing the same configuration. | +| D) | For a blade system, the blade server power consumption of the EUT shall be measured in the half-populated blade chassis configuration
For blade systems, the blade chassis shall be half populated as follows:
  • The number of blade servers required to populate half the number of single-wide blade server slots available in the blade chassis shall be calculated.
  • For blade chassis with multiple power domains, the number of power domains shall be chosen that is closest to filling half of the blade chassis. In a case where there are two choices
| + +**Table 2 – Test configuration of EUT** + +| Index | Detailed requirements | +|-------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| |

that are equally close to filling half of the blade chassis, test with the domain or combination of domains which utilize a higher number of blade servers.

EXAMPLE 1: A blade chassis supports up to 7 single-wide blade servers on two power domains. One power domain supports 3 blade servers and the other supports 4 blade servers. In this example, the power domain which supports 4 blade servers would be fully populated during testing, while the other power domain would remain unpopulated.

EXAMPLE 2: A blade chassis supports up to 16 single-wide blade servers on four power domains. Each of the four power domains supports 4 blade servers. In this example, two of the power domains would be fully populated during testing, while the other two power domains would remain unpopulated.

All user manual or manufacturer recommendations shall be followed for partially populating the blade chassis, which may include disconnecting some of the power supplies and cooling fans for the unpopulated power domains.

If user manual recommendations are not available or are incomplete, then the following guidance shall be followed:

  • • Completely populate the power domains.
  • • If possible, disconnect the power supplies and cooling fans for unpopulated power domains.
  • • Fill all empty bays with blanking panels or an equivalent airflow restriction for the duration of testing.
| +| E) |

The EUT shall be connected to a live Ethernet [IEEE 802.3-2022] network switch.

The live connection shall be maintained for the duration of testing, except for brief lapses necessary for transitioning between link speeds.

| +| F) |

The controller system required to provide the workload harness control of the server EE testing tool, data acquisition, or other EUT testing support shall be connected to the same network switch as the EUT and satisfy all other EUT network requirements.

Both the EUT and controller system shall be configured to communicate via the network.

| +| G) |

The power meter shall be connected to an AC voltage source set to the appropriate voltage and frequency for the test, as specified in Table 1.

| +| H) |

The EUT shall be connected to the measurement power outlet on the power meter following the guidelines in Table 1.

| +| I) |

The data output interface of the power meter and the temperature sensor shall be connected to the appropriate inputs of the controller system.

| +| J) |

It shall be verified that the EUT is configured in its as-shipped configuration.

| +| K) |

It shall be verified that the controller system and EUT are connected on the same internal network via an Ethernet network switch.

| +| L) |

Using a normal ping command, it shall be verified that the controller system and EUT can communicate with each other.

| +| M) |

A server EE testing tool shall be installed on the EUT and the controller system.

| + +# 10 Measurement + +## 10.1 Measurement for active state + +The measurement shall be in accordance with Table 3. + +**Table 3 – Measurement of active state efficiency** + +| Index | Detailed requirements | +|-------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| A) | The EUT shall be rebooted.
System caches and any stored information that may affect the active state efficiency metric shall be flushed. | +| B) | All steps outlined in the user guide of the server EE testing tool shall be followed to successfully run the server EE testing tool.
There shall be no manual intervention or optimization of the controller system, EUT or its internal and external environment during the execution of the server EE testing tool. | +| C) | Once server EE testing tool procedures are completed, the following output files shall be included with all testing results:
  1. 1. Results.xml
  2. 2. Results.html
  3. 3. Results.txt
  4. 4. All results-chart .png files (e.g., results-chart0.png, results-chart1.png, etc.)
  5. 5. Results-details.html
  6. 6. Results-details.txt
  7. 7. All results-details-chart .png files (e.g., results-details-chart0.png, results-details-chart1.png, etc.)
| + +## **10.2 Re-verification and audits** + +Due to the manufacturing variance in components, number of significant power elements in the system and to run to run variations, re-test of an individual server, a server from the same configuration or a server family will result in values that may vary from the initial testing. + +Adjusting for a 90% confidence interval, re-testing values that are within 15% of the passing level shall be acceptable under re-test. Re-test or audit resulting in an error greater than 15% to the designated passing level shall be re-evaluated as a product family to determine compliance. + +For audits and re-verification of power supply units, re-testing of PSU efficiency shall not be lower than the declared value by more than 2% and the power factor shall not be lower than the declared value by more than 10%. Variance beyond these levels shall require re-evaluation of the power supply unit. + +## **10.3 Measurement for power supply** + +### **10.3.1 Measurement for internal power supply** + +The measurement shall be in accordance with Table 4. + +**Table 4 – Measurement of internal power supply** + +| Index | Detailed requirements | +|-------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| A) | For all types of internal power supplies, the efficiency and the power factor shall be measured at 10%, 20%, 50% and 100% of the rated [nameplate] output power. | +| B) | Test set-up, test conditions, and measurement instrument specifications shall comply with clause 8.2. | +| C) | This test procedure assumes that the internal power supply meets the following criteria:
  • • Detailed input and output ratings are available on the name plate or in the manufacturer's literature, specifying the maximum loads that can safely be placed on each individual DC output voltage bus and, where necessary, groupings of those voltage busses.
| + +**Table 4 – Measurement of internal power supply** + +| Index | Detailed requirements | +|-------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| |
  • The power supply has connectors that allow the DC output voltage buses to be connected and disconnected from the powered product non-destructively.
  • The power supply can be easily detached from the housing of the product it powers, without causing harm to other circuits and components of the product.
| +| D) | In the event the above criteria C) are not met, a test board (see clause 10.3.2) shall be provided to enable testing. | + +NOTE 1 – The power supply can be easily detached from the housing of the product it powers, without causing harm to other circuits and components of the product. + +NOTE 2 – Such data could already be available from the manufacturer of the power supply; in such cases, the manufacturer could decide to use them. However, where third party test results are used, it is the responsibility of the manufacturer to assess the trustworthiness of the sources. + +### 10.3.2 Measurement for test board power supply + +#### 10.3.2.1 General + +Tests specified in this clause shall be made on either: + +- The power supply of the computer under test, after it has been disconnected from the powered parts and extracted from the housing; or alternatively; +- Another unit, representative of the built-in power supply. + +#### 10.3.2.2 Test loads + +Active loads such as electronic loads or passive loads such as rheostats may be used as DC test loads. They shall be able to maintain the required current loading set point for each output voltage within an accuracy of $\pm 0.5\%$ . + +#### 10.3.2.3 Test leads and wiring + +Appropriate wires shall be used to avoid excessive overheating and reduce voltage drop across the wires. If measurements are not taken directly at the connector pins, voltage drop against the additional wires shall be taken into account. + +NOTE – If applicable, voltage drop across the input wires will be subtracted from the measured input voltage, and the voltage drop across the output wires will be added to the measured input voltage for the measurement of power efficiency. + +#### 10.3.2.4 Warm up time + +Whereas internal temperature of the components could impact its efficiency, the power supply under test shall be loaded up to the test load for a period of at least 15 minutes or until the reading over two consecutive five-minute intervals does not change by more than $\pm 0.2\%$ . + +#### 10.3.2.5 Power measurements + +The true RMS wattmeter used to carry out AC input power measurements shall meet the requirements of clauses 5.7 and 5.8 of [IEC 62623]. Input power shall be determined using an averaging technique over a minimum of 32 input cycles utilizing the measurement instrument averaging function. + +For appliances connected to more than one phase, the power measurement instrument shall be equipped to measure the total power of all phases connected. + +DC output power measurements shall be made either with a suitably calibrated voltmeter and ampere meter or with a suitably calibrated power meter. + +# 11 Measurement report + +The following metrics/measurements shall be listed in the measurement report: + +- 1) Efficiency metric; +- 2) Reported maximum power. + +It is accepted that the measurement accuracy of the metrics is $\pm 10\%$ . Any subsequent assessment within this range shall be considered to be consistent with the quoted value. + +The following additional information shall also be reported/provided under the technical documentation: + +- 1) Server EE testing tool, test report and supporting data; +- 2) Author, site, and date of the testing; +- 3) Product type; +- 4) Server configuration including: + - a) Component manufacturer, product ID, number of units; + - b) Component product type for APA, CPU, memory, drive (HDD or SSD); + - c) System test model number; + - d) Manufacturer name; + - e) Server product ID. +- 5) Power supply unit test information or reference to a previously conducted test report; +- 6) The extremes of server inlet test temperature during the test; +- 7) Revision numbers for each of test software elements used; +- 8) Software (e.g., Java) revision and source used; +- 9) Controller product model ID; +- 10) Test equipment (power meter, thermal sensor/meter): manufacturer, model, ID and calibration date; +- 11) Server EE testing tool, suite revisions; +- 12) Server EE testing tool, product configuration revision. + +## Bibliography + +- [b-CLC EN 60297] CENELEC EN 60297 series, *Mechanical structures for electrical and electronic equipment. Dimensions of mechanical structures of the 482,6 mm (19 in) series.* +- [b-ETSI EN 300 119] ETSI EN 300 119 series, *Equipment Engineering (EE); European telecommunication standard for equipment practice.* +- [b-ETSI EN 303 470] ETSI EN 303 470 v1.1.1:2019, *Environmental Engineering (EE); Energy Efficiency Measurement methodology and metrics for servers.* +- [b-ETSI ES 204 083] ETSI ES 204 083 v1.1.1:2025, *Environmental Engineering (EE); Energy Efficiency measurement methodology and metrics for heterogeneous servers.* +- [b-EU 2019/424] Commission Regulation (EU) 2019/424 of 15 March 2019 laying down ecodesign requirements for servers and data storage products pursuant to Directive 2009/125/EC of the European Parliament and of the Council and amending Commission Regulation (EU) No. 617/2013. +- [b-Shan] Shan, Amar (2006), *Heterogeneous Processing: a Strategy for Augmenting Moore's Law. Linux Journal, Vol. 2006, No. 142, 80–82.* + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|----------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1315-201705-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg b/marked/L/T-REC-L.1315-201705-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..d029dd4fbf2b92152823b8298396c96c7282e426 --- /dev/null +++ b/marked/L/T-REC-L.1315-201705-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:476aa07e8e41a13b741a431c04ad0f9bd3a7bd0a3822f14a669b12f2abaf0e0d +size 3828 diff --git a/marked/L/T-REC-L.1316-201911-I_PDF-E/e8ba5d4a3a22e24e44f7935ea26afcb0_img.jpg b/marked/L/T-REC-L.1316-201911-I_PDF-E/e8ba5d4a3a22e24e44f7935ea26afcb0_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..8bcda2c01451dbc3cddbdce7f60f1edcb3cde5e9 --- /dev/null +++ b/marked/L/T-REC-L.1316-201911-I_PDF-E/e8ba5d4a3a22e24e44f7935ea26afcb0_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:7e18e4f38b75cc1dacb67027b5abc017d0596259f8f138890e9c4ea02887a12b +size 4177 diff --git a/marked/L/T-REC-L.1316-201911-I_PDF-E/raw.md b/marked/L/T-REC-L.1316-201911-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..cd6c023b0b2cf2bc3459a75410dc47e02a24f466 --- /dev/null +++ b/marked/L/T-REC-L.1316-201911-I_PDF-E/raw.md @@ -0,0 +1,481 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.1316** + +(11/2019) + +SERIES L: ENVIRONMENT AND ICTS, CLIMATE +CHANGE, E-WASTE, ENERGY EFFICIENCY; +CONSTRUCTION, INSTALLATION AND PROTECTION +OF CABLES AND OTHER ELEMENTS OF OUTSIDE +PLANT + +# --- **Energy efficiency framework** + +Recommendation ITU-T L.1316 + +## ITU-T L-SERIES RECOMMENDATIONS + +## **ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT** + +| | | +|--------------------------------------------------------|-------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node elements (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +## Recommendation ITU-T L.1316 + +# Energy efficiency framework + +## Summary + +Recommendation ITU-T L.1316 contains a framework of documents for collecting standards on energy efficiency metrics/key performance indicators (KPIs), measurement methodologies and energy management solutions for information and communication technology (ICT) equipment. + +The Recommendation suggests the selection of the appropriate document to reference when determining energy efficiency. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.1316 | 2019-11-13 | 5 | 11.1002/1000/14081 | + +## Keywords + +Energy efficiency, energy management, methodology, metrics. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2019 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 4 | +| 3.1 Terms defined elsewhere ..... | 4 | +| 3.2 Terms defined in this Recommendation..... | 5 | +| 4 Abbreviations and acronyms ..... | 5 | +| 5 Conventions ..... | 5 | +| 6 Energy efficiency and management general discussion ..... | 5 | +| 7 Energy efficiency metrics and KPI definitions..... | 6 | +| 7.1 ITU-T Recommendations ..... | 6 | +| 7.2 ETSI documents ..... | 7 | +| 7.3 ATIS documents ..... | 8 | +| 8 Energy efficiency measurement methods ..... | 9 | +| 8.1 ITU-T Recommendations ..... | 9 | +| 8.2 ETSI documents ..... | 10 | +| 8.3 ATIS documents ..... | 11 | +| 9 Energy management methods..... | 11 | +| 9.1 ETSI documents on energy management solutions..... | 11 | + + + +## Recommendation ITU-T L.1316 + +# Energy efficiency framework + +# 1 Scope + +The Recommendations are a framework of existing standards, from ITU-T, ETSI and ATIS, covering various aspects of energy efficiency (EE) and energy management. + +This Recommendation covers energy efficiency of: + +- information and communication technology (ICT) goods; +- telecom networks; +- services. + +Standards from other organizations not covered in this Recommendation will be added in future versions. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T L.1302] Recommendation ITU-T L.1302 (2015), *Assessment of energy efficiency on infrastructure in data centres and telecom centres*. +- [ITU-T L.1310] Recommendation ITU-T L.1310 (2017), *Energy efficiency metrics and measurement methods for telecommunication equipment*. +- [ITU-T L.1315] Recommendation ITU-T L.1315 (2017), *Standardization terms and trends in energy efficiency*. +- [ITU-T L.1320] Recommendation ITU-T L.1320 (2014), *Energy efficiency metrics and measurement for power and cooling equipment for telecommunications and data centres*. +- [ITU-T L.1330] Recommendation ITU-T L.1330 (2015), *Energy efficiency measurement and metrics for telecommunication networks*. +- [ITU-T L.1331] Recommendation ITU-T L.1331 (2017), *Assessment of mobile network energy efficiency*. +- [ITU-T L.1332] Recommendation ITU-T L.1332 (2018), *Total network infrastructure energy efficiency metrics*. +- [ITU-T L.1350] Recommendation ITU-T L.1350 (2016), *Energy efficiency metrics of a base station site*. +- [ITU-T L.1351] Recommendation ITU-T L.1351 (2018), *Energy efficiency measurement methodology for base station sites*. +- [ITU-T L.1361] Recommendation ITU-T L.1361 (2018), *Measurement method for energy efficiency of network functions virtualization*. + +| | | +|-------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| [ATIS-0600015] | ATIS-0600015 (2018), Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting – General Requirements. | +| [ATIS-0600015.01] | ATIS-0600015.01 (2014), Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting – Server Requirements. | +| [ATIS-0600015.02] | ATIS-0600015.02 (2016), Energy Efficiency for Telecommunication Equipment: Methodology for Measurement & Reporting – Transport & Optical Access Requirements. | +| [ATIS-0600015.03] | ATIS-0600015.03 (2016), Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting for Router and Ethernet Switch Products. | +| [ATIS-0600015.04] | ATIS-0600015.04 (2017), Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting DC Power Plant – Rectifier Requirements. | +| [ATIS-0600015.05] | ATIS-0600015.05 (2010), Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting Facility Energy Efficiency. | +| [ATIS-0600015.07] | ATIS-0600015.07 (2018), Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting – Wireline Access, Asymmetric Broadband Equipment. | +| [ATIS-0600015.08] | ATIS-0600015.08 (2014), Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting for Small Network Equipment. | +| [ATIS-0600015.09] | ATIS-0600015.09 (2015), Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting of Base Station Metrics. | +| [ATIS-0600015.10] | ATIS-0600015.10 (2015), Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting DC Power Plant – Inverter Requirements. | +| [ATIS-0600015.11] | ATIS-0600015.11 (2016), Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting DC/DC Converter Requirements. | +| [ATIS-0600015.12] | ATIS-0600015.12 (2016), Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting Power Systems – Uninterruptible Power Supply Requirements. | +| [ATIS-0600015.13] | ATIS-0600015.13 (2017), Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting of 802.11xx Wi-Fi Access Points. | +| [ETSI EN 301 575] | ETSI EN 301 575 V1.1.1 (2012), Environmental Engineering (EE); Measurement method for energy consumption of Customer Premises Equipment (CPE). | +| [ETSI EN 303 215] | ETSI EN 303 215 V1.3.1 (2015), Environmental Engineering (EE); Measurement methods and limits for power consumption in broadband telecommunication networks equipment. | + +| | | +|-----------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| [ETSI EN 303 423] | ETSI EN 303 423 V1.2.1 (2018), Environmental Engineering (EE); Electrical and electronic household and office equipment; Measurement of networked standby power consumption of Interconnecting equipment; Harmonised Standard covering the measurement method for EC Regulation 1275/2008 amended by EU Regulation 801/2013. | +| [ETSI EN 303 470] | ETI EN 303 470 V1.1.1 (2019), Environmental Engineering (EE); Energy Efficiency measurement methodology and metrics for servers. | +| [ETSI EN 303 471] | ETSI EN 303 471 V1.1.1 (2019), Environmental Engineering (EE); Energy Efficiency measurement methodology and metrics for Network Function Virtualisation (NFV). | +| [ETSI EN 303 472] | ETSI EN 303 472 V1.1.1 (2018), Environmental Engineering (EE); Energy Efficiency measurement methodology and metrics for RAN equipment. | +| [ETSI EN 305 174-1] | ETSI EN 305 174-1 V1.1.1 (2018), Access, Terminals, Transmission and Multiplexing (ATTM); Broadband Deployment and Lifecycle Resource Management; Part 1: Overview, common and generic aspects. | +| [ETSI EN 305 174-2] | ETSI EN 305 174-2 V1.1.1 (2018), Access, Terminals, Transmission and Multiplexing (ATTM); Broadband Deployment and Lifecycle Resource Management; Part 2: ICT Sites. | +| [ETSI EN 305 200-1] | ETSI EN 305 200-1 (2018), Access, Terminals, Transmission and Multiplexing (ATTM); Energy management; Operational infrastructures; Global KPIs; Part 1: General requirements. | +| [ETSI EN 305 200-2-1] | ETSI EN 305 200-2-1 V1.1.1 (2018), Access, Terminals, Transmission and Multiplexing (ATTM); Energy management; Operational infrastructures; Global KPIs; Part 2: Specific requirements; Sub-part 1: ICT Sites. | +| [ETSI EN 305 200-2-2] | ETSI EN 305 200-2-2 (2018), Access, Terminals, Transmission and Multiplexing (ATTM); Energy management; Operational infrastructures; Global KPIs; Part 2: Specific requirements; Sub-part 2: Fixed broadband access networks. | +| [ETSI EN 305 200-3-1] | ETSI EN 305 200-3-1 V1.1.1 (2018), Access, Terminals, Transmission and Multiplexing (ATTM); Energy management; Operational infrastructures; Global KPIs; Part 3: ICT Sites; Sub-part 1: DCEM. | +| [ETSI ES 201 554] | ETSI ES 201 554 V1.2.1 (2014), Environmental Engineering (EE); Measurement method for Energy efficiency of Mobile Core network and Radio Access Control equipment. | +| [ETSI ES 202 706-1] | ETSI ES 202 706-1 V1.5.1 (2017), Environmental Engineering (EE); Metrics and measurement method for energy efficiency of wireless access network equipment; Part 1: Power Consumption – Static Measurement Method. | +| [ETSI ES 203 136] | ETSI ES 203 136 V1.2.1 (2017), Environmental Engineering (EE); Measurement methods for energy efficiency of router and switch equipment. | +| [ETSI ES 203 228] | ETSI ES 203 228 V1.2.1 (2017), Environmental Engineering (EE); Assessment of mobile network energy. | + +- [ETSI ES 203 475] ETI ES 203 475 V1.1.1 (2017), *Environmental Engineering (EE); Standardization terms and trends in energy efficiency.* +- [ETSI ES 203 539] ETSI ES 203 539 V1.1.1 (2019), *Engineering Environmental (EE); Measurement method for energy efficiency of Network Functions Virtualisation (NFV) in laboratory environment.* +- [ETSI ES 205 200-1] ETSI ES 205 200-1 V1.2.1 (2014), *Access, Terminals, Transmission and Multiplexing (ATTM); Energy management; Global KPIs; Operational infrastructures; Part 1: General requirements.* +- [ETSI ES 205 200-2-1] ETSI ES 205 200-2-1 V1.2.1 (2014), *Access, Terminals, Transmission and Multiplexing (ATTM); Energy management; Global KPIs; Operational infrastructures; Part 2: Specific requirements; Sub-part 1: Data centres.* +- [ETSI ES 205 200-2-2] ETSI ES 205 200-2-2 V1.1.1 (2018), *Access, Terminals, Transmission and Multiplexing (ATTM); Energy management; Global KPIs; Operational infrastructures; Part 2: Specific requirements; Sub-part 2: Fixed broadband access networks.* +- [ETSI TS 102 706-2] ETSI TS 102 706-2 V1.5.1 (2018), *Environmental Engineering (EE); Metrics and Measurement Method for Energy Efficiency of Wireless Access Network Equipment; Part 2: Energy Efficiency – dynamic measurement method.* +- [ETSI TS 105 174-1] ETSI TS 105 174-1 V1.2.1 (2014), *Access, Terminals, Transmission and Multiplexing (ATTM); Broadband Deployment and Energy Management; Part 1: Overview, common and generic aspects.* +- [ETSI TS 105 174-2] ETSI TS 105 174-2 V1.2.1 (2017), *Access, Terminals, Transmission and Multiplexing (ATTM); Broadband Deployment and Energy Management; Part 2: ICT sites.* +- [ETSI TS 105 174-2-2] TS 105 174-2-2 V1.1.1 (2009), *Access, Terminals, Transmission and Multiplexing (ATTM); Broadband Deployment – Energy Efficiency and Key Performance Indicators; Part 2: Network sites; Sub-part 2: Data centres.* +- [ETSI TS 105 174-4-1] ETSI TS 105 174-4-1 (2005), *Access, Terminals, Transmission and Multiplexing (ATTM); Broadband Deployment and Energy Management; Part 4: Access Networks; Sub-part 1: Fixed access networks (excluding cable).* +- [ETSI TS 105 174-5-4] ETSI TS 105 174-5-4 V1.1.1 (2019), *Access, Terminals, Transmission and Multiplexing (ATTM); Broadband Deployment - Energy Efficiency and Key Performance Indicators; Part 5: Customer network infrastructures; Sub-part 4: Data centres (customer).* + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 energy** [ITU-T L.1310]: "The capacity for doing work". In the telecommunication systems, where the primary source of energy is electricity, energy is measured in Joules. + +## **3.2 Terms defined in this Recommendation** + +None. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|--------------------------------------------| +| AC | Alternating Current | +| CPE | Customer Premises Equipment | +| DC | Direct Current | +| DSLAM | Digital Subscriber Line Access Multiplier | +| EE | Energy Efficiency | +| EoL | End of Life | +| FAN | Fixed Access Network | +| GEpon | Gigabit Ethernet Passive Optical Network | +| GPON | Gigabit Passive Optical Network | +| GSM | Global System for Mobile communications | +| ICT | Information and Communication Technology | +| KPI | Key Performance Indicator | +| LTE | Long-Term Evolution | +| MSAM | Multi-Service Access Node | +| MUX | Multiplexer | +| NFV | Network Function Virtualisation | +| OTN | Optical Transport Network | +| RAN | Radio Access Network | +| TDM | Time Division Multiplexing | +| TEER | Telecommunications Energy Efficiency Ratio | +| UMTS | Universal Mobile Telecommunications System | +| UPS | Uninterruptible Power Supply | +| WDM | Wavelength Division Multiplexing | + +# **5 Conventions** + +None. + +# **6 Energy efficiency and management general discussion** + +A general discussion and definition of energy efficiency is presented in [ITU-T L.1315] which contains an explanation of terminology concerning the differences between energy efficiency and energy management. + +[ITU-T L.1315] shall be used as basis for the definition of energy efficiency terminology, ICT equipment working conditions and status. + +# 7 Energy efficiency metrics and KPI definitions + +## 7.1 ITU-T Recommendations + +[ITU-T L.1315] *Standardization terms and trends in energy efficiency* contains general energy efficiency (EE) metrics considerations such as general efficiency definition, useful work concepts for ICT equipment, functioning status/mode and EE; it is technically equivalent to [ETSI ES 203 475]. + +[ITU-T L.1315] shall be used as a reference in other Recommendations when defining energy efficiency metrics and key performance indicators (KPIs). + +[ITU-T L.1310] *Energy efficiency metrics and measurement methods for telecommunication equipment* contains metrics definitions for digital subscriber line access multiplier (DSLAM), multi-service access node (MSAM), gigabit passive optical network (GPON), gigabit Ethernet passive optical network (GEPON), routers, Ethernet switches, wireless access technologies, small networking devices, wavelength division multiplexing (WDM)/time division multiplexing (TDM)/optical transport network (OTN), multiplexer (MUX)/switches and converged packet optical equipment. + +[ITU-T L.1320] *Energy efficiency metrics and measurement for power and cooling equipment for telecommunications and data centres* contains the general definition of metrics, test procedures, methodologies and measurement profiles required to assess the energy efficiency of power and cooling equipment for telecommunications and data centres. + +Metrics and measurement methods are defined for power equipment, alternating current (AC) power feeding equipment (e.g., AC uninterruptible power supply (UPS), direct current (DC)/AC inverters), DC power feeding equipment (such as AC/DC rectifiers, DC/DC converters), solar equipment, wind turbine equipment and fuel cell equipment. + +In addition, metrics and measurement methods are defined for cooling equipment such as air conditioning equipment, outdoor air cooling equipment and heat exchanging cooling equipment. + +[ITU-T L.1330] *Energy efficiency measurement and metrics for telecommunication networks* provides a set of metrics for the assessment of energy efficiency of telecommunication mobile networks, together with proper measurement methods. The technologies covered are: global system for mobile communications (GSM), universal mobile telecommunications system (UMTS) and long-term evolution (LTE) (including LTE advanced (LTE-A)). In particular, this Recommendation defines metrics for mobile network energy efficiency and methods for assessing (and measuring) energy efficiency in operational networks. + +[ITU-T L.1331] *Assessment of mobile network energy efficiency* is an evolution of [ITU-T L.1330] introducing new requirements for radio sites. + +[ITU-T L.1332] *Total network infrastructure energy efficiency metrics* contains metrics definitions used to evaluate the energy efficiency of an entire network consisting of telecommunication equipment and infrastructure equipment; different energy sources of different natures are taken into account. + +[ITU-T L.1350] *Energy efficiency metrics of a base station site* contains energy efficiency metrics used to evaluate the energy efficiency of a base station site considering the energy consumption for: + +- telecom equipment inside the base station site e.g., backhaul, base station equipment; +- the entire infrastructure, including cooling systems, monitoring systems (e.g., power consumption, equipment running status, environment parameters), fire protection and lighting systems for all sites; +- energy losses due to AC/DC rectifiers, generators and cable losses. + +[ITU-T L.1361] *Measurement method for energy efficiency of network functions virtualization* contains metrics definition for network functions virtualization (NFV) environments. All of the different types of VNFs (e.g., firewall, gateway), are not covered in this Recommendation, but it does provides the basis to make an extensible definition. + +## 7.2 ETSI documents + +[ETSI EN 303 472] *Energy Efficiency measurement methodology and metrics for RAN equipment* contains requirements for energy efficiency measurement of radio access networks in use including radio site EE and references to [ITU-T L.1350]. + +[ETSI EN 303 471] *Energy Efficiency measurement methodology and metrics for Network Function Virtualisation (NFV)* contains requirements for energy efficiency measurements of NFV networks in use. + +[ETSI EN 303 470] *Energy Efficiency measurement methodology and metrics for servers* contains metrics and measurement methods relating to computer servers. + +[ETSI EN 303 215] *Measurement methods and limits for power consumption in broadband telecommunication networks equipment* contains metrics definition and measurement methods for fixed wired access technologies. It is used as a reference by [ITU-T L.1310]. + +[ETSI ES 203 539] *Measurement method for energy efficiency of Network Functions Virtualisation (NFV) in laboratory environment* contains metrics definition and measurement methodology for NFV solutions for laboratory testing. It is technically equivalent to [ITU-T L.1361]. + +[ETSI ES 203 475] *Standardization terms and trends in energy efficiency* contains general EE metrics consideration such as general efficiency definition, useful work concept for ICT equipment, functioning status/mode and EE. It is technically equivalent to [ITU-T L.1315]. + +[ETSI ES 203 228] *Assessment of mobile network energy* provides a set of metrics for the assessment of EE of telecommunication mobile networks, together with proper measurement methods. The technologies covered are: GSM, UMTS and LTE (including LTE advanced (LTE-A)). In particular, this Recommendation defines metrics for mobile network energy efficiency and methods for assessing (and measuring) energy efficiency in operational networks. It is technically equivalent to [ITU-T L.1331]; the first version it is technically equivalent to [ITU-T L.1330]. + +[ETSI ES 203 136] *Measurement methods for energy efficiency of router and switch equipment* contains metric definition and measurement methods for router and switch products. + +[ETSI ES 202 706-1] *Metrics and measurement method for energy efficiency of wireless access network equipment; Part 1: Power Consumption - Static Measurement Method* contains metrics definitions and measurement methodologies for the power consumption of wireless access base stations with static loads. + +[ETSI ES 201 554] *Measurement method for Energy efficiency of Mobile Core network and Radio Access Control equipment* contains metrics definitions and measurement methodologies for efficiency of mobile core equipment. + +[ETSI TS 102 706-2] *Metrics and Measurement Method for Energy Efficiency of Wireless Access Network Equipment; Part 2: Energy Efficiency – dynamic measurement method* contains metrics definitions and measurement methodologies for the power consumption of wireless access base stations with a dynamic loads. + +## 7.3 ATIS documents + +[ATIS-0600015] *Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting – General Requirements* provides the methodology to be used by vendors and third-party test laboratories in the formation of a telecommunications energy efficiency ratio (TEER). This document is the base standard for determining telecommunications energy efficiency. + +[ATIS-0600015.01] *Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting – Server Requirements* defines how to measure the TEER of a server. This standard also provides requirements for how equipment vendors shall respond to a TEER request based on a specific application description by making use of relevant data from internal and independent test reports. + +[ATIS-0600015.02] *Energy Efficiency for Telecommunication Equipment: Methodology for Measurement & Reporting – Transport & Optical Access Requirements* specifies the definition of transport and optical access products and systems as well as a methodology to calculate the TEER of a transport or optical access system or network configuration. This standard also provides requirements for how equipment vendors shall respond to a TEER request based on a specific application descriptions by making use of relevant data from internal and independent test reports. + +[ATIS-0600015.03] *Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting for Router and Ethernet Switch Products* specifies the definition of router and Ethernet switch products based on their position in a network, as well as a methodology to calculate the TEER. This standard also provides requirements for how equipment vendors shall respond to a TEER request based on a specific application description by making use of relevant data from internal and independent test reports. + +[ATIS-0600015.04] *Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting DC Power Plant – Rectifier Requirements* defines how to measure the TEER of DC power plant rectifiers. This standard also provides requirements for how equipment vendors shall respond to a TEER request based on a specific application description by making use of relevant data from internal and independent test reports. + +[ATIS-0600015.05] *Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting Facility Energy Efficiency* defines how to measure the TEER of a telecommunications facility. This technical report is built upon facility measurement metrics used in the data centre industry. + +[ATIS-0600015.07] *Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting – Wireline Access, Asymmetric Broadband Equipment* provides the methodology used by vendors and third-party independent laboratories in the formation of a telecommunications energy efficiency ratio. The requirements and definitions in this document are for wireline access equipment that provides standards-based asymmetric broadband service and is deployed in the telecommunications industry. This supplemental standard represents one part of the larger ATIS suite of standards concerning telecommunications energy efficiency [ATIS-0600015]. This supplemental standard [ATIS-0600015.07] specifically addresses access equipment and is to be used in conjunction with [ATIS- 0600015]. + +[ATIS-0600015.08] *Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting for Small Network Equipment* specifies the definition of router and Ethernet switch products based on their position in a network, as well as a methodology to calculate the TEER. This standard also provides requirements for how equipment vendors shall respond to a TEER request based on a specific application description by making use of relevant data from internal and independent test reports. + +[ATIS-0600015.09] *Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting of Base Station Metrics* defines the methodology to be used by vendors and third-party test laboratories in the determination of base station input power and energy efficiency. + +[ATIS-0600015.10] *Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting DC Power Plant – Inverter Requirements* defines how to measure the TEER of telecom inverters for use in DC power plant configurations. This standard also provides requirements for how equipment vendors shall respond to a TEER request based on a specific application description by making use of relevant data from internal and independent test reports. + +[ATIS-0600015.11] *Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting DC/DC Converter Requirements* defines how to measure the TEER of DC/DC converters. This standard also provides requirements for how equipment vendors shall respond to a TEER request based on a specific application description by making use of relevant data from internal and independent test reports. + +[ATIS-0600015.12] *Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting Power Systems – Uninterruptible Power Supply Requirements* provides the methodology to be used by vendors and third-party independent laboratories in the formation of TEER for various typical operating modes of UPS systems. This standard also provides requirements for how equipment vendors shall respond to a TEER request based on a specific application description by making use of relevant data from internal and independent test reports. + +[ATIS-0600015.13] *Energy Efficiency for Telecommunication Equipment: Methodology for Measurement and Reporting of 802.11xx Wi-Fi Access Points* specifies the definition of Wi-Fi access points based on a network they serve, as well as a methodology to calculate the TEER. This standard also provides requirements for how equipment vendors shall respond to a TEER request based on a specific application description by making use of relevant data from internal and independent test reports. + +# 8 Energy efficiency measurement methods + +Standards for efficiency measurement methods are important tools used to define energy efficiency of networks and services, verifying their performance in relation to pre-defined metrics or KPIs. + +## 8.1 ITU-T Recommendations + +[ITU-T L.1315] *Standardization terms and trends in energy efficiency* contains general measurement condition requirements such as environmental conditions, voltage, power sources and power measurement equipment. + +Energy efficiency Recommendations shall use general measurement conditions requirements established by [ITU-T L.1315] unless deviations are necessary due to the nature of ICT goods under energy efficiency measurement. + +[ITU-T L.1310] *Energy efficiency metrics and measurement methods for telecommunication equipment* contains measurement methodologies for DSLAM, MSAM, GPON, GEpon, routers, Ethernet switches, wireless access technologies, small networking devices, WDM/TDM/OTN MUX/switches and converged packet optical equipment. + +[ITU-T L.1302] *Assessment of energy efficiency on infrastructure in data centres and telecom centres* specifies an energy efficiency assessment methodology for data centres and telecom centres, test equipment accuracy requirements, assessment periods, assessment conditions and calculation methods. Concerning data centres and telecom centres, this Recommendation considers assessment + +methods for the efficiency of the entire data centre/telecom centre as well as part of the data centre/telecom centre. + +[ITU-T L.1320] *Energy efficiency metrics and measurement for power and cooling equipment for telecommunications and data centres* contains the general definition of metrics, test procedures, methodologies and measurement profiles required to assess the energy efficiency of power and cooling equipment for telecommunications and data centres. + +Metrics and measurement methods are defined for power equipment, AC power feeding equipment (such as AC UPS, DC/AC) inverters), DC power feeding equipment (such as AC/DC rectifiers, DC/DC converters), solar equipment, wind turbine equipment and fuel cell equipment. + +In addition, metrics and measurement methods are defined for cooling equipment such as air conditioning equipment, outdoor air cooling equipment and heat exchanging cooling equipment. + +[ITU-T L.1330] *Energy efficiency measurement and metrics for telecommunication networks* provides a set of metrics for the assessment of energy efficiency of telecommunication mobile networks, together with proper measurement methods. The technologies covered are: GSM, UMTS and LTE (including LTE advanced (LTE-A)). In particular, this Recommendation defines metrics for mobile network energy efficiency and methods for assessing (and measuring) energy efficiency in operational networks. + +[ITU-T L.1331] *Assessment of mobile network energy efficiency* is an evolution of [ITU-T L.1330] introducing new requirement of radio sites. + +[ITU-T L.1332] *Total network infrastructure energy efficiency metrics* contains measurement methods used to evaluate the energy efficiency of an entire network consisting of telecommunication equipment and infrastructure equipment; different energy sources of different natures are taken into account. + +[ITU-T L.1351] *Energy efficiency measurement methodology for base station sites* contains the methodology for base-station site energy efficiency parameter measurement in line with metrics established by [ITU-T L.1350]. + +This Recommendation describes how to realize measurements of parameters establishing requirements on: + +- measurement points; +- measurement conditions; and +- instrumentation. + +This Recommendation also considers continuous monitoring of site energy efficiency parameters. It does not specify metrics, but refers to the metrics defined in [ITU-T L.1350]. + +[ITU-T L.1361] *Measurement method for energy efficiency of network functions virtualization* contains measurement methods for NFV environments, it does not try to cover all of the different types of VNFs (e.g., firewall, gateway), but provides the basis to make an extensible definition. + +## 8.2 ETSI documents + +[ETSI EN 301 575] *Measurement method for energy consumption of Customer Premises Equipment (CPE)* defines the methodology and test conditions to measure the power consumption of end-user broadband equipment in different operating states: disconnected mode, off mode, standby, idle states, low-power states, on mode. Moreover, these different modes of operation are defined. + +The methods of measurements are applicable to CPE which can be directly connected to the mains. + +[ETSI EN 303 423] *Electrical and electronic household and office equipment; Measurement of networked standby power consumption of Interconnecting equipment; Harmonised Standard covering the measurement method for EC Regulation 1275/2008 amended by EU Regulation* + +801/2013 contains power consumption measurement methods for network standby equipment in line with European regulations. + +Other ETSI related documents are reported in clause 7.2. + +## 8.3 ATIS documents + +ATIS related documents are reported in clause 7.3. + +# 9 Energy management methods + +ETSI released a series of documents reported in clause 9.1 dealing with energy management KPI definitions and measurement for different ICT technologies. These documents relate to the energy management of ICT solutions in operational conditions. + +## 9.1 ETSI documents on energy management solutions + +[ETSI ES 205 200-1] *Access, Terminals, Transmission and Multiplexing (ATM); Energy management; Global KPIs; Operational infrastructures; Part 1: General requirements* describes the energy management landscape of the operational infrastructures of broadband deployment addressed by this multi-part deliverable, their inter-relationship and boundaries. + +[ETSI ES 205 200-2-1] *Access, Terminals, Transmission and Multiplexing (ATM); Energy management; Global KPIs; Operational infrastructures; Part 2: Specific requirements; Sub-part 1: Data centres* specifies global key performance indicators (KPIEE) in relation to energy management for operator data centres (ODCs), operator sites and customer data centres (CDCs) and addresses the following objectives: + +- energy consumption; +- task efficiency; +- energy re-use; +- renewable energy. + +[ETSI ES 205 200-2-2] *Access, Terminals, Transmission and Multiplexing (ATM); Energy management; Global KPIs; Operational infrastructures; Part 2: Specific requirements; Sub-part 2: Fixed broadband access networks* specifies requirements of a global KPI for energy management (KPIEM) and their underpinning Objective KPIs addressing the following objectives for the fixed access networks (FANs) of broadband deployment: + +- energy consumption; +- task effectiveness; +- renewable energy. + +[ETSI TS 105 174-1] *Access, Terminals, Transmission and Multiplexing (ATM); Broadband Deployment and Energy Management; Part 1: Overview, common and generic aspects* provides an overview of this multi-part deliverable covering energy management and broadband deployment. + +[ETSI TS 105 174-2] *Access, Terminals, Transmission and Multiplexing (ATM); Broadband Deployment and Energy Management; Part 2: ICT sites* details measures which may be taken to improve the energy efficiency within ICT sites for broadband deployment. + +[ETSI TS 105 174-2-2] *Access, Terminals, Transmission and Multiplexing (ATM); Broadband Deployment – Energy Efficiency and Key Performance Indicators; Part 2: Network sites; Sub-part 2: Data centres* details measures which may be taken to improve the energy efficiency within operators sites and data centres for broadband deployment. + +[ETSI TS 105 174-4-1] *Access, Terminals, Transmission and Multiplexing (ATM); Broadband Deployment and Energy Management; Part 4: Access Networks; Sub-part 1: Fixed access networks* + +(excluding cable) details measures which may be taken to improve the energy efficiency of access networks for broadband deployment. + +[ETSI TS 105 174-5-4] *Access, Terminals, Transmission and Multiplexing (ATTM); Broadband Deployment – Energy Efficiency and Key Performance Indicators; Part 5: Customer network infrastructures; Sub-part 4: Data centres (customer)* details measures which may be taken to improve the energy efficiency within industrial premises (single-tenant) by virtue of broadband deployment. + +[ETSI EN 305 200-1] *Access, Terminals, Transmission and Multiplexing (ATTM); Energy management; Operational infrastructures; Global KPIs; Part 1: General requirements* describes the energy management landscape of the operational infrastructures of broadband deployment addressed by this multi-part deliverable, their inter-relationship and boundaries. + +[ETSI EN 305 200-2-1] *Access, Terminals, Transmission and Multiplexing (ATTM); Energy management; Operational infrastructures; Global KPIs; Part 2: Specific requirements; Sub-part 1: ICT Sites* specifies requirements for a global KPI for energy management ( $KPI_{EM}$ ) and its underpinning objective KPIs addressing the following objectives for the ICT sites of broadband deployment: + +- energy consumption; +- task effectiveness; +- energy reuse; +- renewable energy. + +[ETSI EN 305 200-2-2] *Access, Terminals, Transmission and Multiplexing (ATTM); Energy management; Operational infrastructures; Global KPIs; Part 2: Specific requirements; Sub-part 2: Fixed broadband access networks* specifies the requirements for a global KPI for energy management ( $KPI_{EM}$ ) and their underpinning objective KPIs addressing the following objectives for the fixed access networks (FANs) of broadband deployment: + +- energy consumption; +- task effectiveness; +- renewable energy. + +[ETSI EN 305 200-3-1] *Access, Terminals, Transmission and Multiplexing (ATTM); Energy management; Operational infrastructures; Global KPIs; Part 3: ICT Sites; Sub-part 1: DCEM* specifies requirements for a global KPI for energy management ( $KPI_{DCEM}$ ) and their underpinning objective KPIs addressing the following objectives for the ICT sites of broadband deployment: + +- energy consumption; +- task effectiveness; +- energy reuse; +- renewable energy. + +[ETSI EN 305 174-1] *Access, Terminals, Transmission and Multiplexing (ATTM); Broadband Deployment and Lifecycle Resource Management; Part 1: Overview, common and generic aspects* is part 1 of a multi-part deliverable which specifies the general engineering of various broadband infrastructures to enable the most effective energy management (and management of other resources) and the appropriate measures for end-of-life (EoL) treatment of ICT equipment. This document provides an overview of the ETSI EN 305 174 series of standards together with a definition of the common and generic aspects to which the other standards in the series conform. + +[ETSI EN 305 174-2] *Access, Terminals, Transmission and Multiplexing (ATTM); Broadband Deployment and Lifecycle Resource Management; Part 2: ICT Sites* specifies requirements for resource management of ICT sites, as a combination of: + +- energy management; +- management of EoL procedures for ICT equipment. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | 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L.1328 (09/2025)** + +SERIES L: Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant + +Energy efficiency, smart energy and green data centres + +--- + +## **Specification for waste heat reuse in telecommunication rooms and data centres** + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue circular emblem with a stylized globe and the letters 'ITU' in white. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +### **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|---------------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| Infrastructure including node elements (except cables) | L.200-L.249 | +| General aspects and network design | L.250-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| Optical fibre cable maintenance | L.300-L.329 | +| Infrastructure maintenance | L.330-L.349 | +| Operation support and infrastructure management | L.350-L.379 | +| Disaster management | L.380-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1328 + +## Specification for waste heat reuse in telecommunication rooms and data centres + +## Summary + +In the face of the rapid growth in the size and power density of global telecommunication rooms and data centres, the heat generated by ICT equipment is growing dramatically, but the generated heat is mostly discarded. The waste heat reuse can contribute to reducing the energy consumption of other facilities, which are outside of the boundary of the telecommunication rooms and data centres by heating the facilities. Therefore, the use of waste heat reuse technology facilitates energy saving and carbon reduction in non-ICT sectors. + +Recommendation ITU-T L.1328 describes the use cases of waste heat reuse and defines the key metrics of waste heat recovery and reuse. Further, the measurement methodology including the calculation method for the defined key metrics is also described. + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.1328 | 2025-09-22 | 5 | 11.1002/1000/16415 | + +## Keywords + +Cooling system, data centre, telecommunication room, waste heat recovery, waste heat reuse. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, and information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2025 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|----------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 1 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 2 | +| 6 Development background and effectiveness of waste heat reuse..... | 2 | +| 7 Challenges and limitations in waste heat reuse ..... | 2 | +| 8 Technical methods for waste heat recovery..... | 3 | +| 8.1 Waste heat recovery in water-cooled air-cooling systems ..... | 4 | +| 8.2 Waste heat recovery in air-cooled air-cooling systems ..... | 4 | +| 8.3 Waste heat recovery in liquid cooling systems ..... | 4 | +| 9 Workflow of waste heat recovery and reuse system ..... | 5 | +| 10 Key metrics of waste heat recovery and reuse..... | 6 | +| 10.1 Power usage effectiveness ..... | 6 | +| 10.2 Energy reuse factor..... | 6 | +| 10.3 Recovery factor ..... | 7 | +| 10.4 Waste heat reuse rate ..... | 7 | +| 10.5 Waste heat reuse overall energy efficiency ..... | 7 | +| 11 Measurement methodology for waste heat reuse key parameters ..... | 7 | +| 12 Calculation of key metrics and their application requirement..... | 8 | +| Appendix I – A data centre calculation use case ..... | 11 | +| Bibliography..... | 13 | + + + +# Recommendation ITU-T L.1328 + +## Specification for waste heat reuse in telecommunication rooms and data centres + +## 1 Scope + +This Recommendation presents the technologies for the reuse of waste heat in telecommunications rooms and data centres and describes the followings: + +- Current use cases and benefits of waste heat reuse; +- Development issues currently encountered with waste heat reuse; +- Technical specifications for waste-heat reuse technologies, with requirements for the establishment of relevant indicators. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T L.1302] Recommendation ITU-T L.1302 (2015), *Assessment of energy efficiency on infrastructure in data centres and telecom centres*. + +[ISO/IEC 30134-6] ISO/IEC 30134-6:2021, *Information technology – Data centres key performance indicators – Part 6: Energy Reuse Factor (ERF)*. + +## 3 Definitions + +### 3.1 Terms defined elsewhere + +None. + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 cooling capacity:** The cooling power of air conditioners, referring to the rate that heat is removed from a space. + +NOTE 1 – The unit used to measure cooling capacity is tons per hour or British thermal units (BTUs). + +NOTE 2 – Based on [b-ITU-T L.1320]. + +**3.2.2 recovery factor:** An indicator for measuring the potential of waste heat recovery in telecommunication rooms and data centres. + +**3.2.3 waste heat recovery and reuse:** An energy-saving technology that recovers and reuses the heat generated during energy consumption through equipment and devices. + +**3.2.4 waste heat reuse overall energy efficiency:** An indicator for judging the capacity of waste heat recovery systems. + +**3.2.5 waste heat reuse rate:** A performance indicator for measuring waste heat reuse systems. + +## 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|------------------------------| +| ERF | Energy Reuse Factor | +| GHG | Greenhouse Gas | +| HVDC | High-Voltage Direct Current | +| KPI | Key Performance Indicator | +| PUE | Power Usage Effectiveness | +| UPS | Uninterruptible Power Supply | + +## 5 Conventions + +None. + +## 6 Development background and effectiveness of waste heat reuse + +Telecommunication rooms and data centres serve as consistent sources of reliable, low-temperature, high-capacity waste heat. By definition, waste heat refers to the heat generated by an equipment, unit or chip not as their useful work but as a secondary effect. With the acceleration of IT equipment consolidation and rising computing density, the generation of continuous and stable waste heat is inevitable. Reusing this waste heat not only enhances comprehensive energy utilization efficiency but also reduces energy consumption in non-ICT sectors by heating the facilities. As the scale of the telecommunication rooms and data centres expands and the efficiency of waste heat reuse systems improves, the potential for waste heat recovery grows significantly. + +Global implementations demonstrate the technology's viability. Finland and Norway have established mature commercial applications and generated economic and environmental benefits by using air source heat pumps for residential heating in data centres [b-Deymi]. Denmark's 50 000 m2 campus data centre supplies 100 000 MWh of waste heat annually to 6 900 households [b-Zhang-1]. The US, Japan and China also have successful cases. For example, a Chinese data centre uses magnetic levitation heat pumps to reuse 5 233 kW of waste heat, reducing 525 tons of standard coal equivalent energy consumption and 1 310 tons of CO2 emissions annually [b-Zhang-1]. + +As an energy-saving and emission-reduction measure, waste heat reuse technology holds broad market prospects. It helps to reduce heat waste and GHG emissions in urban heating. With technological innovation in the future, the quality of waste heat will be enhanced, and its application scenarios will become more diverse. + +From a technical perspective, providing technical specification guidance and building a standard system are crucial. The technical specifications for waste heat recovery and reuse can optimize the system framework of communication rooms and data centres and develop evaluation indicators. These indicators will quantitatively evaluate reuse efficiency and value, and guide engineering implementation, further improve the utilization rate of waste heat, promote cross-industry collaboration, form a sustainable industrial development model, and accelerate the achievement of carbon neutrality goals. + +## 7 Challenges and limitations in waste heat reuse + +There are still a number of challenges and limitations that need to be addressed in the reuse of waste heat: + +### 1) Low-grade waste heat characteristics + +Waste heat generated in telecommunication rooms and data centres is typically of low-grade quality, posing significant challenges to direct utilization. Low-grade waste heat specifically refers to thermal energy with relatively low temperatures (usually ranging from around 30°C to 80°C) that is produced as an unavoidable by-product of equipment operation and lacks sufficient temperature levels for direct application in most heating or industrial scenarios. The operational temperature thresholds of key components such as CPUs, memory units and hard drives inherently restrict the heat output temperature. Consequently, the thermal temperature carried by hot air from direct natural cooling or heated water from indirect natural cooling usually falls below the levels required for practical applications. To make this waste heat usable, secondary heating processes are often essential, which necessitates additional energy inputs and increases overall energy consumption. + +### 2) Immaturity of recovery technologies + +Current waste heat recovery technology is still relatively immature, leading to difficulties in efficient heat capture, especially in small and medium-sized data centres and telecommunications rooms. If recycling efficiency and reliability are not significantly improved, the large-scale deployment of waste heat reuse systems remains challenging, limiting the realization of their full potential. + +### 3) Restricted reuse applications + +Existing waste heat reuse applications are predominantly limited to a narrow range of scenarios, mainly focusing on domestic hot water supply and space heating. These applications are highly seasonal, resulting in substantial periods of under-utilization of waste heat resources throughout the year. The lack of innovative and diversified reuse applications that can operate effectively across different seasons and environmental conditions severely restricts the overall utilization of waste heat. + +### 4) Lack of cross-industry integration + +During the planning and design stages, there is a significant lack of cross-industry integration between data centre operators and urban heating systems, largely due to individual business interests. This lack of coordination has resulted in the absence of viable business models and profit mechanisms for waste heat reuse. Moreover, concerns about potential system-level risks and uncertainties regarding the long-term stability and safety of integrated waste heat reuse systems have further deterred infrastructure transformation efforts. Therefore, an efficient and sustainable operational framework for waste heat utilization is yet to be established. + +### 5) Economic constraints + +A large number of data centres are in remote areas, far from residential and commercial clusters, which means a lack of nearby application scenarios for waste heat reuse. Long-distance transmission of waste heat inevitably leads to a significant temperature drop and energy loss. These factors increase both the initial investment required for infrastructure construction and the ongoing operational costs. The combined effect of high upfront investment and continuous operational expenses extends the payback period of waste heat recovery projects, making them economically unattractive and a major obstacle to widespread adoption. + +## 8 Technical methods for waste heat recovery + +The common thermodynamic principle of waste heat recovery is to use electrical energy or mechanical energy to transfer heat energy from a low-temperature heat source to high temperature heat source. At present, heat pump units are mainly used to realize the recovery and reuse of waste heat from telecommunication rooms and data centres and are used for heating and hot water supply. According to the different locations of waste heat utilization points and system settings, the design forms of waste heat systems are also different. At present, the waste heat recovery technology of telecommunication rooms and data centres needs to be combined with air-conditioning systems to realize. Different air-conditioning systems adopt different methods for waste heat recovery. + +### 8.1 Waste heat recovery in water-cooled air-cooling systems + +Most large data centres use water-cooled air-conditioning systems for cooling, and the heat recovery of water-cooled systems is divided into chilled water heat recovery and cooling water heat recovery, of which the chilled water recovery system is more mature. The water-cooled system can be directly connected to the heat pipe network or hot water pipe network by adding a water source heat pump on the chilled water side (Figure 1). The water source heat pump uses the principle of heat exchange to warm up the circulating water in the heat pipe network, which reduces the energy consumption of the water-cooling unit and further realizes the energy saving of the air-conditioning system. + +![Schematic diagram of waste heat recovery of water cooling (Figure 1).](cfda9df1319e04207eb28bcefd1dab7b_img.jpg) + +The diagram illustrates a water-cooled air-cooling system with waste heat recovery. On the left, a **Cooling tower** is connected to a **Cooling water pump**. A red line labeled **Cooling water return** goes from the pump to the **Water-cooled chillers**. A blue line labeled **Cooling water supply** goes from the chillers to the pump. The chillers are connected to a **Chilled water pump**, which is connected to **Air conditioning terminals**. A yellow line labeled **Chilled water return circuit** goes from the terminals back to the chillers. A blue dotted line labeled **Cold energy supplied to the water cooling system** goes from the terminals to a **Water source heat pump**. A yellow dotted line labeled **Waste heat from water cooling system** goes from the chillers to the heat pump. The heat pump is connected to **Connecting heating pipes**, which lead to a yellow dashed line labeled **Chilled water recovery**. + +Legend: + +- Blue line – Low temperature cooling water supply +- Red line – High temperature cooling water return +- Yellow line – Chilled water return circuit +- Blue dotted line – Cold energy supplied to the water cooling system +- Yellow dotted line – Waste heat from water cooling system + +L.1328(25) + +Schematic diagram of waste heat recovery of water cooling (Figure 1). + +Figure 1 – Schematic diagram of waste heat recovery of water cooling + +### 8.2 Waste heat recovery in air-cooled air-cooling systems + +In the last decade, large number of telecommunication rooms and data centres that use air side free cooling systems have been built. There are two main ways to recover waste heat from air-cooled systems. One method is to recover the waste heat through an air-to-air heat exchanger and supply hot air to a nearby plant room. This method can only be used close to the telecommunication rooms or data centre on a small scale. Another method can realize large-scale utilization of telecommunication rooms and data centre waste heat (Figure 2). The hot air in the hot aisle heats the water in the cooling coil. Then the water source heat pump uses the principle of heat exchange to warm the circulating water in the heat pipe network, which reduces the energy consumption of the air side free cooling system and further realizes telecommunication room and data centre heat recovery. + +![Schematic diagram of waste heat recovery of air cooling (Figure 2).](053f1077d592e6622cd21dc4bb4cb366_img.jpg) + +The diagram illustrates an air-cooled air-cooling system with waste heat recovery. On the left, an **Air cooled data centre** is shown with a **Cooling coil**. Red arrows indicate hot air being exhausted from the top. Blue arrows indicate cold air being supplied to the bottom. The cooling coil is connected to a **Cold water pump**, which is connected to **Heat pump units**. A blue dotted line labeled **Cold energy supplied to the water cooling system** goes from the heat pump units to the cooling coil. A yellow dotted line labeled **Waste heat from water cooling system** goes from the cooling coil to the heat pump units. The heat pump units are connected to **Connecting heating pipes**, which lead to a yellow dashed line labeled **Chilled water recovery**. + +Legend: + +- Blue dotted line – Cold energy supplied to the water cooling system +- Yellow dotted line – Waste heat from water cooling system + +L.1328(25) + +Schematic diagram of waste heat recovery of air cooling (Figure 2). + +Figure 2 – Schematic diagram of waste heat recovery of air cooling + +### 8.3 Waste heat recovery in liquid cooling systems + +Liquid cooling refers to the cooling technology that takes away the heat generated by the server operation through liquid medium. Liquid cooling technology is now gradually being introduced in high-density data centres. Liquid cooling heat dissipation not only has a large heat capacity but also + +has faster heat transfer. As liquid cooling equipment bears a higher water temperature, the waste heat reuse of liquid cooling has more technical advantages. Firstly, it has a higher waste heat grade and more stable heating capacity, and secondly, the system is simpler and easier to connect with the heat reuse system, which has excellent heat recovery performance. + +At present, the liquid cooling technology is classified into cold plate, submerged and spray methods. In the submerged and spray method, the cooling liquid is in direct contact with the server components, and the stability and reliability of the coolant itself and its impact on the performance of IT components are subject to continuous attention and verification. Cold plate liquid cooling is the use of the coolant flowing through the back of the chip in the cold plate channel across the cold plate wall and the chip heat exchange, so as to take away the heat. This method is commonly used in industry because it has advantages in reliability, service life, maintenance convenience, initial investment, etc. Cold plate liquid cooling is currently more mature than other liquid cooling methods, and attempts have been made to combine it with waste heat recovery technology (Figure 3). The higher the coolant temperature of liquid cooling, the more conducive it is to reuse. In summary, waste heat reuse by liquid cooling technology will be a future application trend. + +![Schematic diagram of waste heat recovery of cold plate liquid cooling. The diagram shows a flow of cooling water (blue lines) and return water (red lines) between a Dry cooler, a Liquid-cooled circulation pump, Liquid-cooled heat transfer units, Liquid-cooled cabinets, and Heat pump units. A legend at the bottom explains the line types: Blue line – Low temperature chilled water supply; Red line – High temperature chilled water return; Blue dotted line – Cold energy supplied to the liquid cooling system; Red dotted line – Waste heat from liquid cooling system. The label L.1328(25) is present in the bottom right.](e9314c83043183351ed74908e9bf2f90_img.jpg) + +Legend: + +- Blue line – Low temperature chilled water supply +- Red line – High temperature chilled water return +- Blue dotted line – Cold energy supplied to the liquid cooling system +- Red dotted line – Waste heat from liquid cooling system + +L.1328(25) + +Schematic diagram of waste heat recovery of cold plate liquid cooling. The diagram shows a flow of cooling water (blue lines) and return water (red lines) between a Dry cooler, a Liquid-cooled circulation pump, Liquid-cooled heat transfer units, Liquid-cooled cabinets, and Heat pump units. A legend at the bottom explains the line types: Blue line – Low temperature chilled water supply; Red line – High temperature chilled water return; Blue dotted line – Cold energy supplied to the liquid cooling system; Red dotted line – Waste heat from liquid cooling system. The label L.1328(25) is present in the bottom right. + +**Figure 3 – Schematic diagram of waste heat recovery of cold plate liquid cooling** + +## 9 Workflow of waste heat recovery and reuse system + +The waste heat recovery and reuse system in telecommunications rooms and data centres consists of three parts: the cooling system, heat recovery system and reuse system. When the temperature of the recovered waste heat reaches a sufficiently high level, it can be directly applied to heating purposes. In cases where the temperature is inadequate, secondary treatment and heating processes are needed prior to its reuse. Figure 4 provides a more intuitive overview of the entire technical process of waste heat recovery and reuse from the perspective of heat flow. It can be used to better assess, organize and evaluate the implementation of waste heat recovery and reuse technologies in telecommunications rooms and data centres. It also helps to understand and set key technical evaluation indicators in the future, analyse the quantity and quality of waste heat, select more specific parameters to judge the potential, availability, and effectiveness of waste heat reuse, and provide decision support for choosing to use waste heat reuse systems. + +![Schematic diagram of the workflow of the waste heat recovery and reuse system. The diagram shows the flow of waste heat from telecommunication rooms and data centres through a cooling system, then split into two main paths: Water/Liquid cooling system and Air cooling system. The Water/Liquid cooling system leads to a Water source heat pump, Plate heat exchanger, and Heat pump system for temperature upgrade, which then lead to District heating domestic hot water. The Air cooling system leads to an Absorption chiller for cooling production, which leads to Cooling supply for data centres. Both the Air cooling system and the Heat pump system for temperature upgrade also lead to Direct reuse, which leads to Direct delivery to heat demand areas. The diagram is labeled L.1328(25).](d4af765160d04ecef538e5066006dc77_img.jpg) + +``` + +graph LR + TRDC[Telecommunication rooms data centres] --> CS[Cooling system] + CS --> WLS[Water/Liquid cooling system] + CS --> ACS[Air cooling system] + WLS --> WSH[Water source heat pump] + WLS --> PHE[Plate heat exchanger] + WLS --> HPSU[Heat pump system for temperature upgrade] + WSH --> DH[District heating domestic hot water] + PHE --> DH + HPSU --> DH + ACS --> AC[Absorption chiller for cooling production] + AC --> CD[Cooling supply for data centres] + ACS --> DR[Direct reuse] + HPSU --> DR + DR --> DDH[Direct delivery to heat demand areas] + +``` + +Schematic diagram of the workflow of the waste heat recovery and reuse system. The diagram shows the flow of waste heat from telecommunication rooms and data centres through a cooling system, then split into two main paths: Water/Liquid cooling system and Air cooling system. The Water/Liquid cooling system leads to a Water source heat pump, Plate heat exchanger, and Heat pump system for temperature upgrade, which then lead to District heating domestic hot water. The Air cooling system leads to an Absorption chiller for cooling production, which leads to Cooling supply for data centres. Both the Air cooling system and the Heat pump system for temperature upgrade also lead to Direct reuse, which leads to Direct delivery to heat demand areas. The diagram is labeled L.1328(25). + +**Figure 4 – Schematic diagram of the workflow of the waste heat recovery and reuse system** + +## 10 Key metrics of waste heat recovery and reuse + +### 10.1 Power usage effectiveness + +The unified index for evaluating telecommunication rooms and data centres is power usage effectiveness (PUE), which is the ratio of total energy consumption of data centre to total energy consumption of IT equipment. Using waste heat reuse technology can improve the energy use efficiency of infrastructures, so more key indicators are needed to measure its energy saving and carbon reduction effect and the economic benefits [ITU-T L.1302]. + +### 10.2 Energy reuse factor + +[ISO/IEC 30134-6] defines energy reuse factor (ERF) as a KPI to quantify the reuse of the energy consumed in a data centre. ERF is defined as the ratio of energy being reused divided by the sum of all energy consumed in a data centre. The ERF does reflect the efficiency of the reuse process; the reuse process is not part of a data centre. + +*ERF* is defined as shown in Equation (10-1): + +$$ERF = \frac{E_{Reuse}}{E_{DC}} \quad (10-1)$$ + +$E_{Reuse}$ : energy from the data centre (annual) that is used outside of the data centre and which substitutes partly or totally energy needed outside the data centre boundary (annual); + +$E_{DC}$ : total data centre energy consumption (annual), includes IT equipment energy consumption plus all the energy that is consumed to support the following infrastructures, such as power delivery, cooling system and others. + +*ERF* provides a way to determine the factor of energy reuse. *ERF* ranges from 0 to 1.0. An *ERF* of 0 means no energy is reused, while a value of 1.0 means that, theoretically, all the energy brought into the data centre is reused. Any equipment outside of the data centre boundary for increasing the temperature delivered, such as heat pumps, shall not be included in the calculation. + +*ERF* in this Recommendations focuses on energy reuse across the entire data centre. When dealing with telecommunication rooms and data centres with waste heat recovery and reuse, more specific indicators are required to assess effectiveness. These indicators can better guide the overall improvement of cooling systems and energy applications in data centres. + +### 10.3 Recovery factor + +Firstly, an indicator is needed to measure the waste heat recovery potential of telecommunication rooms and data centres, defined as the recovery factor (*RF*). The *RF* can be expressed as the ratio of the corresponding heat emitted by air-conditioning systems to the heat generated by IT equipment (Equation 10-2), and the larger the value of the *RF*, the more recoverable waste heat there is, and the greater the potential for waste heat recovery. + +$$RF = \frac{\text{Heat emissions from cooling systems}}{\text{Heat generated from IT equipment}} \quad (10-2)$$ + +### 10.4 Waste heat reuse rate + +When the waste heat reuse system is actually applied in telecommunication rooms and data centres, an index is needed to measure the actual performance of the heat reuse system, which is designed to be expressed as the waste heat reuse rate (*WHRr*), defined as the proportion of the actual reused heat to the reusable heat (Equation 10-3). The greater the *WHRr*, the greater the proportion of heat actually recovered and the more heat reused, the better the actual performance capability of the waste heat reuse system and the better the energy-saving effect. + +$$WHRr = \frac{\text{Actual reused heat}}{\text{Reusable heat}} \quad (10-3)$$ + +### 10.5 Waste heat reuse overall energy efficiency + +The overall energy efficiency of the waste heat reuse (*WHRee*) is defined to demonstrate the energy-saving benefits of using this technology. *WHRee* can be expressed by comparing the reused heat and the electricity consumption of the recovery system (Equation 10-4). The higher the energy efficiency, the greater the value and significance of the waste heat recovery system. + +$$WHRee = \frac{\text{Actual reused heat}}{\text{Energy consumption of waste heat recovery system}} \quad (10-4)$$ + +## 11 Measurement methodology for waste heat reuse key parameters + +Figure 5 illustrates the components and energy flow within the telecommunication rooms or data centres, as well as those of the associated waste heat recovery and reuse systems. Measuring instruments are used to measure power/heat consumption, and the measurement points should be set up with reference to the location requirements of each measurement point in Figure 5. The location of the measuring instruments should be convenient for the collection and management of energy consumption data. In order to facilitate calculations and comparisons, the time intervals for measuring electricity and heat used in the parameter calculations are set as 12 months. + +The measurement parameter of total energy consumption shall be taken as the sum of energy consumption of M1 and M2 before the power is fed into the transformer. The energy consumption of the cooling system of the information equipment service of the data centre is M4 and the load of the IT equipment is M6. M7, M8 and M9 are the heat measurement parameters, which can be calculated by using the measured temperature parameters of the cooling medium. M10 is the total energy consumption of the waste heat recovery system. The electricity consumption represented by M10 can be derived directly from power meter measurements. Table 1 shows the specific measurement parameters and units of M1 to M10. + +**Table 1 – Measurement parameters and units of M1 to M10** + +| Measurement parameter | Measured value [Unit] | +|-----------------------|----------------------------------------------------------------------| +| M1 | System power supply [KWh] | +| M2 | Electricity supplied by other means of electricity supply [KWh] | +| M3 | Electricity consumption of other systems such as lighting [KWh] | +| M4 | Electricity consumption of cooling systems [KWh] | +| M5 | Electricity through UPS/HVDC [KWh] | +| M6 | Energy consumption of IT equipment [KWh] | +| M7 | Heat obtained from cooling systems emission [GJ] | +| M8 | Return heat from waste heat recovery systems to cooling systems [GJ] | +| M9 | Actual reused heat from waste heat recovery system [GJ] | +| M10 | Total energy consumption of the waste heat recovery system [KWh] | + +![Schematic diagram of measuring points for measurement parameters. The diagram shows the flow of electricity and heat through various components. Electricity from the grid (M1) and other sources (M2) enters a switch and then a power transformation/distribution system. From there, it splits into a UPS/HVDC (M5), computer room lighting and other systems (M3), and a cooling and air conditioning system (M4). The UPS/HVDC feeds into a column head cabinet/small busbar (Isolation transformer) (M6), which then feeds into the IT load. The cooling and air conditioning system emits waste heat (M7) to a waste heat recovery system (M10). The waste heat recovery system also receives electricity (M10) and a heating supply (M9). The waste heat recovery system then feeds into a waste heat reuse system (M8). A battery is connected to the UPS/HVDC. A boundary line separates the internal components from the external waste heat recovery and reuse systems.](4ee27dbf5ef12e7b58b0ef0937bc5a5e_img.jpg) + +Schematic diagram of measuring points for measurement parameters. The diagram shows the flow of electricity and heat through various components. Electricity from the grid (M1) and other sources (M2) enters a switch and then a power transformation/distribution system. From there, it splits into a UPS/HVDC (M5), computer room lighting and other systems (M3), and a cooling and air conditioning system (M4). The UPS/HVDC feeds into a column head cabinet/small busbar (Isolation transformer) (M6), which then feeds into the IT load. The cooling and air conditioning system emits waste heat (M7) to a waste heat recovery system (M10). The waste heat recovery system also receives electricity (M10) and a heating supply (M9). The waste heat recovery system then feeds into a waste heat reuse system (M8). A battery is connected to the UPS/HVDC. A boundary line separates the internal components from the external waste heat recovery and reuse systems. + +**Figure 5 – Schematic diagram of measuring points for measurement parameters** + +## 12 Calculation of key metrics and their application requirement + +Based on the definition of key metrics for waste heat recovery and reuse outlined in clause 10 and the measurement methods detailed in clause 11, these indicators – *PUE*, *ERF*, *RF*, *WHRr* and *WHRee* – can be further calculated. + +*PUE* can be directly calculated as: + +$$PUE = \frac{\text{Total energy consumption of communication room/data center}}{\text{Total energy consumption of IT equipment}} = \frac{M1}{M6} \quad (12-1)$$ + +Where: + +M1: is the total energy consumption of the communication room/data centre + +$$M6 = \text{Energy consumption of IT equipment} = P \times t \quad (12-2)$$ + +*P*: Actual input power (kW) + +*t*: Actual operating time (h) + +*ERF* can be directly calculated as: + +$$ERF = \frac{E_{\text{Reuse}}}{E_{\text{Dc}}} = \frac{M7}{M1+M2} \quad (12-3)$$ + +Where: + +*M2*: is electricity supplied by other means of electricity supply + +$$M7 = \text{Heat emissions from cooling systems} = C_1 \times m_1 \times \Delta T_1 \quad (12-4)$$ + +*C*1: Specific heat capacity (kJ/(kg·K)) + +*m*1: Mass flow of the heat exchange medium (kg/s) + +$\Delta T_1$ : Waste heat recovery system inlet and outlet fluid temperature difference (K) + +NOTE 1 – The value of *M7* obtained is the unit of heat GJ, which needs to be converted into the unit of energy KWh for comparison. + +*RF* can be directly calculated as: + +$$RF = \frac{\text{Heat emissions from cooling systems}}{\text{Heat generated from IT equipment}} = \frac{M7}{M6} \quad (12-5)$$ + +Where: + +$$M6 = \text{Energy consumption of IT equipment} = P \times t \quad (12-6)$$ + +*P*: Actual input power (kW) + +*t*: Actual operating time (h) + +NOTE 2 – The required value in the formula is heat. The value of *M6* obtained is the unit of energy KWh, which needs to be converted into the unit of heat GJ for comparison. + +*WHRr* can be directly calculated as: + +$$WHRr = \frac{\text{Actual reused heat}}{\text{Reusable heat}} = \frac{M9}{M7} \quad (12-7)$$ + +Where: + +$$M9 = \text{Actual reused heat from waste heat recovery system} = C_2 \times q_2 \times \Delta T_2 \quad (12-8)$$ + +*C*2: Specific heat capacity (kJ/(kg·K)) + +*q*2: Mass flow of the heat exchange medium (kg/s) + +$\Delta T_2$ : Waste heat reuse system inlet and outlet fluid temperature difference (K) + +*WHRee* can be directly calculated as: + +$$WHRee = \frac{\text{Actual reused heat}}{\text{Energy consumption of waste heat recovery system}} = \frac{M9}{M10} \quad (12-9)$$ + +Where: + +*M10*: is total energy consumption of the waste heat recovery system + +NOTE 3 – The value of *M9* obtained is the unit of heat GJ, which needs to be converted into the unit of energy KWh for comparison. + +During the operation of the waste heat recovery and reuse system, heat loss is an inevitable aspect of the heat transfer process. If the proportion of heat loss to the total heat transferred, as calculated in practice, falls below the engineering's allowable error range, the heat loss can be disregarded. Additionally, this approach facilitates simplified modelling and energy efficiency assessments of the waste heat recovery system in subsequent stages. + +Before calculating the parameters of the waste heat recovery and reuse system, it is also necessary to determine the location of the waste heat recovery equipment according to the actual situation and the installation method to ensure that the equipment is installed firmly and stably. Check the working condition of the waste heat recovery equipment, including pipelines, valves, pumps and other equipment is intact, to ensure that there is no air leakage, water leakage and other phenomena. + +The application of waste heat recovery and reuse requires consideration of key issues such as the recoverability, availability, efficiency, cost and benefit of the waste heat. In terms of environmental factors, waste heat can be used more efficiently in areas where heating and hot water are required, such as in cold regions. For warmer climates, more consideration needs to be given to the application scenarios and recovery efficiency of the recovered waste heat before deciding whether waste heat recovery and reuse is appropriate. + +## Appendix I + +### A data centre calculation use case + +(This appendix does not form an integral part of this Recommendation.) + +This appendix provides a waste heat reuse use case in a data centre. The data centre is located in a medium-temperate continental monsoon climate, with long winters and short summers and four distinct seasons. Winter is long and cold, while summer is short and cool. The annual average temperature is 5.6°C, the highest monthly average temperature is 23.6°C, the lowest monthly average temperature is –15.8°C, and the winter is long and the summer is short. + +The data centre area within Building 1 covers approximately 25 000 m2 and houses 3 000 IT racks. With a designated IT load capacity of 12 000 kW, it is powered by four 10 kV mains, each capable of delivering around 11 000 kVA. The data centre employs a water-side free cooling system, enhanced by three high-voltage centrifugal chillers, each with a cooling capacity of 1 700 RT. + +Furthermore, a waste heat recovery system is installed, consisting of two water source heat pump units, each boasting a heating capacity of 200 RT. This system efficiently utilizes waste heat to provide warmth to office buildings within the data centre park, covering a total heating area of approximately 23 000 m2. + +![A photograph of a large industrial facility, likely a data center, showing complex piping and machinery. The scene is divided into two panels. The left panel shows a series of large yellow pipes running horizontally across the floor, with several vertical pipes extending upwards. The right panel shows a more complex arrangement of pipes, including a prominent red vertical pipe and a green horizontal pipe, along with a white control panel or unit on the floor. The floor is concrete, and the overall environment is industrial and well-lit.](c3ee41c6d46565ab4198d0a9c69108c5_img.jpg) + +A photograph of a large industrial facility, likely a data center, showing complex piping and machinery. The scene is divided into two panels. The left panel shows a series of large yellow pipes running horizontally across the floor, with several vertical pipes extending upwards. The right panel shows a more complex arrangement of pipes, including a prominent red vertical pipe and a green horizontal pipe, along with a white control panel or unit on the floor. The floor is concrete, and the overall environment is industrial and well-lit. + +**Figure I.1 – Schematic diagram of the air-conditioning system and waste heat recovery system in this data centre** + +In 2023, the total power consumption (M1 plus M2) of the B1 data centre for the year amounted to 120 800 000 kW·h. The average operating IT equipment input power rating is 10 616 kW and one year of operating time is 8 760 hours, with the IT load's total annual consumption (M6) reaching 93 000 000 kW·h. Notably, the waste heat generated is medium-temperature chilled water at 15/21°C. The data centre provides 55/50°C hot water to the office buildings in the data centre park, and the total annual residual heat recovery (M7) stands at 7 650 GJ. Additionally, the heat supply (M9) of the waste heat recovery system is approximately equal to the heat absorbed from the data centre (M7) and the natural power consumption of the system (M10). The total annual heating capacity (M9) is 9 000 GJ, and the waste heat recovery system annual power consumption is 500 000 kW·h. + +Consequently, the data centre's *RF* is 2.26%, indicating efficient energy utilization. + +$$M6 = P \times t = 10616 \text{ kW} \times 8760 \text{ h} \approx 93000000 \text{ kW} \cdot \text{h}$$ + +$$M7 = C \times m_1 \times \Delta T_1 = 4.2 \times \frac{10^3 \text{ kJ}}{\text{kg}} \cdot K \times 364285 \text{ kg} \times 5K = 7650 \text{ GJ}$$ + +$$RF = \frac{M7}{M6} = \frac{7650 \text{ GJ}}{93000000 \text{ kW}\cdot\text{h}} = \frac{2100000 \text{ kW}\cdot\text{h}}{93000000 \text{ kW}\cdot\text{h}} = 2.26\%$$ + +The waste heat reuse rate ( $WHRr$ ) is 1.24, reflecting the system's effectiveness in harnessing and redirecting waste heat for heating purposes. + +$$M9 \approx M7 + M10 = 7650 \text{ GJ} + 1800 \text{ GJ} = 9450 \text{ GJ}$$ + +$$WHRr = \frac{M9}{M7} = \frac{9450 \text{ GJ}}{7650 \text{ GJ}} = 1.24$$ + +The waste heat reuse overall energy efficiency ( $WHRee$ ) is 5.25, reflecting the overall energy efficiency of the waste heat recovery system. + +$$WHRee = \frac{M9}{M10} = \frac{9450 \text{ GJ}}{500000 \text{ kW}\cdot\text{h}} = \frac{2625000 \text{ kW}\cdot\text{h}}{500000 \text{ kW}\cdot\text{h}} = 5.25$$ + +![Schematic diagram of the data centre showing energy flows and components.](8592a32c2fdf17c1e562f0ba6b7e8e1a_img.jpg) + +The diagram illustrates the energy flow and components of a data centre. It is divided into two main sections by a 'Boundary' line. + +**Top Section (Data Centre Internal Components):** + +- Electricity** (Four 10 kW mains 11000 kVA per mains) enters via **M1** to a **Switch**. +- The **Switch** connects to **M2**, which feeds into an **Emergency supply** and **Renewable and other self-contained power sources**. +- The **Switch** also connects to a **Power transformation/distribution system**. +- This system feeds into **M3** (Computer room lighting and other systems), **M4** (Cooling and air conditioning system), and **M5** (UPS/HVDC). +- The **Battery** is connected to the **UPS/HVDC**. +- M5** feeds into a **Column head cabinet/small busbar (Isolation transformer)**, which then connects to **M6** (IT load). +- The **IT load** is labeled as 3000 racks 12 MW. +- The **Cooling and air conditioning system** (M4) is connected to a **Chilled water system with three high-voltage centrifugal chiller**. + +**Bottom Section (Waste Heat Recovery and Reuse):** + +- Waste heat** (21/15°C chilled water) from the cooling system enters via **M7** into the **Waste heat recovery system**. +- Cooling supply** (15/21°C chilled water) enters via **M8** into the same system. +- Electricity** enters via **M10** into the **Waste heat recovery system**. +- The system includes a **Two water source heat pump**. +- Heating supply** (60/55°C hot water) exits via **M9** into the **Waste heat reuse system**. +- The **Waste heat reuse system** is connected to an **Office building heating system**. + +Reference: L.1328(25) + +Schematic diagram of the data centre showing energy flows and components. + +**Figure I.2 – Schematic diagram of the data centre** + +## Bibliography + +- [b-ITU-T L.1320] Recommendation ITU-T L.1320 (2014), *Energy efficiency metrics and measurement for power and cooling equipment for telecommunications and data centres*. +- [b-Deymi] Deymi-Dashtebayaz, M., and Valipour-Namanlo, S. (2019), *Thermoeconomic and Environmental Feasibility of Waste Heat Recovery of a Data Center using Air Source Heat Pump*, *Journal of Cleaner Production*, Vol. 219, 117-126. +<> +- [b-Zhang-1] Zhang, Q., Meng, Z., Hong, X., Zhan, Y., Liu, J., Dong, J., Bai, T., Niu, J., and Jamal Deen, M. (2021), *A Survey on Data Center Cooling Systems: Technology, Power Consumption Modeling and Control Strategy Optimization*, *Journal of Systems Architecture* Vol. 19, 102253. +<> +- [b-Zhang-2] Zhang, S., Liu, S., Shen, Y., Shukla, A., Rehman Mazhar, A., and Chen, T. (2024), *Critical Review of Solar-assisted Air Source Heat Pump in China*, *Renewable and Sustainable Energy Reviews* Vol. 193, 114291. +<> + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|----------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, 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+CONSTRUCTION, INSTALLATION AND PROTECTION +OF CABLES AND OTHER ELEMENTS OF OUTSIDE +PLANT + +Energy efficiency, smart energy and green data centres + +# --- **Assessment of mobile network energy efficiency** + +Recommendation ITU-T L.1331 + +## ITU-T L-SERIES RECOMMENDATIONS + +## ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT + +| | | +|---------------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node elements (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000–L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200–L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300–L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400–L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500–L.1599 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700–L.1799 | + +For further details, please refer to the list of ITU-T Recommendations. + +## Recommendation ITU-T L.1331 + +# Assessment of mobile network energy efficiency + +## Summary + +Recommendation ITU-T L.1331 aims to provide a better understanding of the energy efficiency of mobile networks. The focus of this Recommendation is on the metrics and methods of assessing energy efficiency in operational networks. + +The networks considered are those whose size and scale could be defined by topologic, geographic or demographic boundaries. + +This Recommendation explains how to extrapolate the measurements made on partial networks to the level of the total network. Such a simplified approach is proposed as a way of making approximate energy efficiency evaluations at the level of network elements and cannot therefore be considered sufficient for the entire network operation including, for example, transport. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.1331 | 2017-04-06 | 5 | 11.1002/1000/13147 | +| 2.0 | ITU-T L.1331 | 2020-09-22 | 5 | 11.1002/1000/14303 | +| 3.0 | ITU-T L.1331 | 2022-01-13 | 5 | 11.1002/1000/14940 | + +## Keywords + +Energy efficiency, metrics, mobile, networks. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2022 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|------------|-----------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 3.1 | Terms defined elsewhere ..... | 2 | +| 3.2 | Terms defined in this Recommendation..... | 3 | +| 4 | Abbreviations and acronyms ..... | 3 | +| 5 | Conventions ..... | 5 | +| 6 | Network under test definition ..... | 5 | +| 6.1 | Introduction ..... | 5 | +| 6.2 | Test parameter categorization..... | 7 | +| 6.3 | Network classification..... | 8 | +| 7 | Metrics for energy efficiency assessment..... | 11 | +| 7.1 | Introduction ..... | 11 | +| 7.2 | Energy consumption metrics ..... | 11 | +| 7.3 | Performance metrics..... | 13 | +| 7.4 | Mobile network energy efficiency metrics..... | 15 | +| 8 | Measurement of energy efficiency ..... | 16 | +| 8.1 | Introduction ..... | 16 | +| 8.2 | Time duration of the measurement..... | 16 | +| 8.3 | Measurement procedures..... | 16 | +| 9 | Extrapolation for overall networks ..... | 21 | +| 9.1 | Extrapolation approach..... | 21 | +| 9.2 | Extrapolation method ..... | 21 | +| 9.3 | Extrapolation reporting tables ..... | 22 | +| 10 | Assessment report..... | 24 | +| 10.1 | Introduction of the assessment report..... | 24 | +| 10.2 | Report on the network area under test ..... | 24 | +| 10.3 | Report of sites under test ..... | 26 | +| 10.4 | Report of site measurement ..... | 27 | +| 11 | Implementation guidelines ..... | 29 | +| Appendix I | – Implementation examples ..... | 30 | +| I.1 | Implementation examples..... | 30 | +| I.2 | Examples of reporting data..... | 30 | +| | Bibliography..... | 36 | + +## Introduction + +Recommendation ITU-T L.1331 considers the definition of metrics and methods used to measure the energy performance of mobile radio access networks and adopts an approach based on the measurement of such performance on small networks, for feasibility and simplicity purposes. Such a simplified approach is proposed for approximating energy efficiency evaluations and cannot be considered as a reference for planning evaluation purposes throughout the network operation process. The same approach was introduced in [b-ETSI TR 103 117]. Measurements in testing laboratories of the efficiency of the base stations is treated in [b-ETSI ES 202 706-1]. + +Recommendation ITU-T L.1331 also provides a method to extrapolate the assessment of energy efficiency to wider networks. + +The general outcome of the application of the method specified is based on the "Assessment report" introduced in clause 10; implementation guidelines are given in clause 11. An example of an application of the method is given for better readability and ease of use in Appendix I. + +Recommendation ITU-T L.1331 was developed jointly by ETSI TC EE and ITU-T Study Group 5 and published by ITU and ETSI as Recommendation ITU-T L.1331 and ETSI Standard ETSI ES 203 228 respectively, which are technically equivalent. + +## Recommendation ITU-T L.1331 + +# Assessment of mobile network energy efficiency + +# 1 Scope + +This Recommendation aims to provide a better understanding of the energy efficiency of mobile networks in particular considering the networks' evolution in different periods of time. The focus of this Recommendation is on metrics for energy efficiency and methods of assessing (and measuring) energy efficiency in operational networks. + +This Recommendation defines the topology and level of analysis needed to assess energy efficiency. + +The analysis includes radio base stations, backhauling systems, radio controllers (RCs) and other infrastructure radio site equipment. The technologies involved are global system for mobile communication (GSM), universal mobile telecommunications service (UMTS), long term evolution (LTE) and 5G New Radio (NR). + +Aiming to also consider the slicing approach of the networks from 5G onwards, the metrics are extended to the latency of the network itself versus the energy consumed, in addition to the metrics based on traffic and on coverage, already existing for legacy networks that are still valid. + +Both homogeneous and heterogeneous networks are considered, whose size and scale could be defined by topologic, geographic or demographic boundaries. An example of a network defined by topologic boundaries consists of a control node (whenever applicable), its supported access nodes and related network elements. Networks could also be defined by geographic boundaries, such as city-wide, national or continental, or they could be defined by demographic boundaries, such as urban or rural networks. + +This Recommendation also applies to so-called "partial" networks, for which a measurement method is also recommended. The specification extends the measurements made in partial networks to the wider, so-called "total" network energy efficiency estimation, such as the network in a geographical area, the network in an entire country or the network of a mobile network operator (MNO). + +Terminal (end-user) equipment is outside the scope of this Recommendation and is not considered in the energy efficiency measurement. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T L.1330] Recommendation ITU-T L.1330 (2015), *Energy efficiency measurement and metrics for telecommunication networks*. +- [ITU-T Q.1742.1] Recommendation ITU-T Q.1742.1 (2002), *IMT-2000 references to ANSI-41 evolved core network with cdma2000 access network*. +- [ITU-R M.2410-0] Recommendation ITU-R M.2410-0 (2017), *Minimum requirements related to technical performance for IMT-2020 radio interface(s)*. + +- [ETSI ES 202 336-12] ETSI ES 202 336-12 V1.1.1 (2015), *Environmental Engineering; Monitoring and control interface for infrastructure equipment (power, cooling and building environment systems used in telecommunications networks); Part 12: ICT equipment power, energy and environmental parameters monitoring information model.* +- [ETSI TS 123 203] ETSI TS 123 203 V12.7.0 (2015), *Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; Policy and charging control architecture (3GPP TS 23.203 version 12.7.0 Release 12).* +- [ETSI TS 125 104] ETSI TS 125 104 V11.3.0 (2012), *Universal Mobile Telecommunications System (UMTS); Base Station (BS) radio transmission and reception (FDD) (3GPP TS 25.104 version 11.3.0 Release 11).* +- [ETSI TS 128 554] ETSI TS 128 554 V15.2.0 (2019), *5G; Management and orchestration; 5G end to end Key Performance Indicators (KPI).* +- [ETSI TS 132 405] ETSI TS 132 405 V11.1.1 (2013), *Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; Telecommunication management; Performance Management (PM); Performance measurements; Universal Terrestrial Radio Access Network (UTRAN) (3GPP TS 32.405 version 11.1.1 Release 11).* +- [ETSI TS 132 412] ETSI TS 132 412 V11.1.0 (2013), *Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; Telecommunication management; Performance Management (PM) Integration Reference Point (IRP): Information Service (IS) (3GPP TS 32.412 version 11.1.0 Release 11).* +- [ETSI TS 132 425] ETSI TS 132 425 V12.0.0 (2014), *LTE; Telecommunication management; Performance Management (PM); Performance measurements Evolved Universal Terrestrial Radio Access Network (E-UTRAN) (3GPP TS 32.425 version 12.0.0 Release 12).* +- [ETSI TS 136 104] ETSI TS 136 104 V11.2.0 (2012), *LTE; Evolved Universal Terrestrial Radio Access (E-UTRA); Base Station (BS) radio transmission and reception (3GPP TS 36.104 version 11.2.0 Release 11).* +- [ETSI TS 136 314] ETSI TS 136 314 V11.1.0 (2013), *LTE; Evolved Universal Terrestrial Radio Access (E-UTRA); Layer 2 – Measurements (3GPP TS 36.314 version 11.1.0 Release 11).* +- [ETSI TS 152 402] ETSI TS 152 402 V11.0.0 (2012), *Digital cellular telecommunications system (Phase 2+); Telecommunication management; Performance Management (PM); Performance measurements – GSM (3GPP TS 52.402 version 11.0.0 Release 11).* +- [ISO/IEC 17025] ISO/IEC 17025:2005, *General requirements for the competence of testing and calibration laboratories.* + +# 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +#### 3.1.1 backhaul equipment: See [ITU-T L.1330] + +- 3.1.2 **base station U:** See [ITU-T L.1330] +- 3.1.3 **distributed RBS:** See [ITU-T L.1330] +- 3.1.4 **end-to-end latency** [b-ETSI TS 122 261]: The time that it takes to transfer a given piece of information from a source to a destination, measured at the communication interface, from the moment it is transmitted by the source to the moment it is successfully received at the destination. +- 3.1.5 **energy efficiency (EE):** See [ITU-T L.1330] +- 3.1.6 **energy saving feature:** See [ITU-T L.1330] +- 3.1.7 **integrated BS:** See [ITU-T L.1330] +- 3.1.8 **mobile network (MN):** See [ITU-T L.1330] +- 3.1.9 **mobile network coverage energy efficiency:** See [ITU-T L.1330] +- 3.1.10 **mobile network data energy efficiency:** See [ITU-T L.1330] +- 3.1.11 **mobile network energy consumption:** See [ITU-T L.1330] +- 3.1.12 **mobile network energy efficiency:** See [ITU-T L.1330] +- 3.1.13 **mobile network operator (MNO):** See [ITU-T L.1330] +- 3.1.14 **mobile network operator penetration ratio:** See [ITU-T L.1330] +- 3.1.15 **mobile network performance delivered:** See [ITU-T L.1330] +- 3.1.16 **power consumption:** See [ITU-T L.1330] +- 3.1.17 **radio access network:** See [ITU-T Q.1742.1] +- 3.1.18 **telecommunication network:** See [ITU-T L.1330] +- 3.1.19 **virtualized network function (VNF)** [b-ETSI GS NFV 003]: Implementation of an NF that can be deployed on a Network Function Virtualization Infrastructure (NFVI). + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following term: + +- 3.2.1 **site energy efficiency (SEE):** A metric used to determine the energy efficiency of a telecommunication site. SEE is defined by the ratio of "IT equipment energy" and "Total site energy", which generally includes rectifiers, cooling, storage, security and IT equipment. + +## 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|----------|-----------------------------------------------------------------------------------------| +| O&M | Operation and Maintenance | +| BH | Backhaul | +| BS | Base Station | +| CC | Central Cloud | +| CoA | Coverage Area | +| CoA_geo | total geographical area under investigation and within the operators' licence agreement | +| CoA_des | designated coverage area as designed by network planning | +| CoA_qdes | quality factor describing how well users are covered within the coverage area | +| CR | Coverage Ratio | + +| | | +|------------------|-----------------------------------------------| +| CRAN | Cloud Radio Access Network | +| CS | Circuit Switched | +| DC | Data Centre | +| DCA | Designed Coverage Area | +| DL | Downlink | +| DP | Dominant Penetration | +| DU | Dense Urban | +| DV | Data Volume | +| DV MN | Data Volume of the Mobile Network | +| E2E | End-to-End | +| EC | Energy Consumption | +| EC MN | Energy Consumption of the Mobile Network | +| EDC | Edge Cloud | +| EDGE | Enhanced Data GSM Environment | +| EE | Energy Efficiency | +| EE MN | Energy Efficiency of the Mobile Network | +| E-UTRA | Evolved UMTS Terrestrial Radio Access Network | +| FAO | Food and Agriculture Organization | +| GHG | Greenhouse Gas | +| GSM | Global System for Mobile communication | +| HARQ | Hybrid Automatic Repeat Request | +| ICT | Information Communications Technology | +| KPI | Key Performance Indicator | +| LC | Local Cloud | +| LTE | Long Term Evolution | +| MDT | Minimization of Drive Tests | +| MN | Mobile Network | +| MNO | Mobile Network Operator | +| MP | Minor Penetration | +| NA | Not Applicable | +| NR | New Radio | +| NDP | Non-Dominant Penetration | +| O&M | Operations and Maintenance | +| PS | Packet Switched | +| PSL | Packet Switched Large packages dominating | +| PSS | Packet Switched Small packages dominating | +| QCI | QoS Class Identifier | + +| | | +|-------|---------------------------------------------| +| QoS | Quality of Service | +| RA | Radio Access | +| RAB | Radio Access Bearer | +| RAN | Radio Access Network | +| RAP | Remote Access Point | +| RAT | Radio Access Technology | +| RC | Radio Controller | +| RF | Radio Frequency | +| RNC | Radio Network Controller | +| RRC | Radio Resource Control | +| RU | Rural | +| SEE | Site Energy Efficiency | +| SI | Site Infrastructure | +| SINR | Signal to Interference plus Noise Ratio | +| SU | Suburban | +| TCO | Total Cost of Ownership | +| TE | Telecommunication Equipment | +| TMA | Tower Mounted Amplifier | +| TTI | Transmission Time Interval | +| U | Urban | +| UE | User Equipment | +| UE-BS | User Equipment to Base Station | +| UL | Uplink | +| UMTS | Universal Mobile Telecommunications Service | +| UN | United Nations | +| URLLC | Ultra-Reliable Low Latency Communication | +| UTRAN | UMTS Terrestrial Radio Access Network | +| VNF | Virtualized Network Function | +| VoLTE | Voice over LTE | + +## 5 Conventions + +None. + +# 6 Network under test definition + +### 6.1 Introduction + +The mobile radio access network under investigation includes all the equipment that is necessary to run a radio access (RA) network or sub-network (see Figure 1 as a reference to the elements considered in this Recommendation). + +– Base stations (BSs) (see [ETSI TS 125 104] and [ETSI TS 136 104]): + +- Wide area BSs; +- Medium range BSs; +- Local area BSs; +- Home BSs; + +NOTE – Home BSs (and Wi-Fi access points) are not considered in this Recommendation and are for further study. + +– Site equipment (e.g., air conditioners, rectifiers/batteries, fixed network equipment); + +– Multiaccess EDGE equipment + +– Backhaul (BH) equipment required to interconnect the BS used in the assessment with the core network; + +– RC; + +– Gateways to connect to the cloud. + +Power consumption and energy efficiency measurements of individual mobile network elements are described in several standards (e.g., [b-ETSI ES 202 706-1] and [b-ETSI TS 102 706-2] for radio BSs). This Recommendation describes the energy consumption (EC) and mobile network (MN) energy efficiency measurements in operational networks. + +As a comprehensive and detailed EC measurement of the complete network of a country or mobile network operator (MNO) may not be viable, the total network is split into a small number of networks with a limited size (i.e., "sub-networks"). + +These sub-networks are defined to represent specific characteristics, for example: + +- Capacity-limited networks representing urban (U) and dense urban (DU) networks; +- Suburban (SU) networks with high requirements for coverage and capacity; +- Rural (RU) networks, which are usually coverage limited. + +The size and scale of the sub-networks are defined by topologic, geographic or demographic boundaries. For networks defined by topologic boundaries, an example could include: an RC, its supported access nodes and related network elements. Networks could also be defined by geographic boundaries, such as city-wide, national or continental networks. Networks could also be defined by demographic boundaries, such as urban or rural networks. + +The sub-networks analysed might consist of macro-only BSs or heterogeneous networks or what is actually implemented in real-world networks. Figure 1 shows a sub-network's general layout. + +The tests defined in this Recommendation for sub-networks provide a basis to estimate energy efficiency for large networks of one MNO or within an entire country, applying the extrapolation methods described in clause 9. + +![Figure 1: Network under test definition. This diagram shows a central cloud connected to a radio controller (RC). The RC is connected to two traditional sites via backhaul links. Each traditional site contains a BS site with BS and site equipment, or a medium range BS connected to a local area BS. The central cloud is also connected to cloud sites and unlicensed multi-connectivity. This includes a local cloud connected to a BS site (with BS radio and site equipment), a local area BS, and a medium range BS. A transport link connects to unlicensed local area BSs. A legend indicates that dashed lines represent control data and solid lines represent user data. The label L.1331(20)_F01 is present in the bottom right.](af7916c89a458fdab6c3f443217388ae_img.jpg) + +Figure 1: Network under test definition. This diagram shows a central cloud connected to a radio controller (RC). The RC is connected to two traditional sites via backhaul links. Each traditional site contains a BS site with BS and site equipment, or a medium range BS connected to a local area BS. The central cloud is also connected to cloud sites and unlicensed multi-connectivity. This includes a local cloud connected to a BS site (with BS radio and site equipment), a local area BS, and a medium range BS. A transport link connects to unlicensed local area BSs. A legend indicates that dashed lines represent control data and solid lines represent user data. The label L.1331(20)\_F01 is present in the bottom right. + +**Figure 1 – Network under test definition** + +The functions outlined in Figure 1 could also be implemented in a cloud radio access network (CRAN). + +The generic layout design for the cloud sites is defined in Figure 2. + +![Figure 2: Generic CRAN architecture layout. This diagram illustrates three domains: Central cloud, Edge cloud, and Radio access. The Central cloud is divided into 'Not included' (IP core network equipment) and 'Included' (Central servers (CS), Switching Eq. (SE), Other Telecom Eq. (TE)). The 'Included' part connects to the Edge cloud, which contains three VNF server (SV) units. These SVs connect to the Radio access domain, which contains three Remote access point (RAP) units. Each RAP is connected to an antenna (Ant.). The label L.1331(20)_F02 is present in the bottom right.](cab0834804fb031b43865554cc8d06ab_img.jpg) + +Figure 2: Generic CRAN architecture layout. This diagram illustrates three domains: Central cloud, Edge cloud, and Radio access. The Central cloud is divided into 'Not included' (IP core network equipment) and 'Included' (Central servers (CS), Switching Eq. (SE), Other Telecom Eq. (TE)). The 'Included' part connects to the Edge cloud, which contains three VNF server (SV) units. These SVs connect to the Radio access domain, which contains three Remote access point (RAP) units. Each RAP is connected to an antenna (Ant.). The label L.1331(20)\_F02 is present in the bottom right. + +**Figure 2 – Generic CRAN architecture layout** + +The RA domain consists of the remote access points (RAPs) dedicated to the CRAN under investigation. A typical RAP would include the radio, baseband and optical transport equipment. It performs real-time eNB tasks (e.g., scheduler) which is installed near the transmitting antennas. + +The edge cloud (EDC) domain consists of small datacentres dedicated to telecommunication functions, including virtualized network function (VNF) servers used by the CRAN under investigation. A typical EDC datacentre would perform non-real-time eNB tasks, such as administration and operations and maintenance (O&M). + +The central cloud (CC) domain consists of a multiserver datacentre (DC) including central servers (CSs), switching equipment (SE) and other telecommunication equipment (TE) if needed. CC datacentres are usually very far from most of the served EDC. + +### 6.2 Test parameter categorization + +Metrics used for the energy efficiency assessment of mobile networks require the definition and collection of a range of parameters and variables. These are separated into two categories: + +- 1) Parameters and variables required to calculate the network energy efficiency; +- 2) Parameters needed to allow network energy efficiency evaluation. + +The first category describes a set of network variables as described in clause 7 (EC, delivered bits, coverage) to be used to calculate the energy efficiency. + +The second category includes parameters which are not directly required in the energy efficiency calculation. These parameters describe network characteristics, such as geographical conditions, population density, coverage area, targeted data rates and climate zones, and are used to interpolate from the measured sub-network to a larger network as described in clause 9. These parameters can be used to interpret variations in energy efficiency results of different networks. Test parameters are listed in Table 1. + +**Table 1 – Test parameter categorization** + +| Category | Parameter | Remarks | +|----------|---------------------------------------------|-----------------------------------------------------------------------------------------------| +| 1 | EC MN | Measured network energy consumption | +| 1 | Capacity (DV) | As defined in clause 7.3 | +| 1 | Coverage area | As defined in clause 8.3.3 | +| 1 | Latency | As defined in clause 7.3.3 | +| 2 | Demography | Population density as defined in clause 6.3.2 | +| 2 | Topography | As defined in clause 6.3.3 | +| 2 | Climate zones | As defined in clause 6.3.4 | +| 2 | Additional classification classes | As defined in clause 6.3.5 | +| 2 | Circuit switched/packet switched data ratio | Describes the fraction of circuit switched traffic vs. packet switched traffic in the network | + +### 6.3 Network classification + +#### 6.3.1 Introduction to network classification + +To allow an extrapolation from the measured sub-networks (i.e., "partial" networks) to a complete network (i.e., "total" or "overall" networks), the test areas shall be classified into demography, topography and climate zones as described in the following clauses. + +The environmental classes used for network classification are: demography, topography and climate zones and are described in clauses 6.3.2 to 6.3.4. + +#### 6.3.2 Demography + +For the test purposes defined in this Recommendation, the mobile network shall be split into domains depending on the population density. The following population density values per domain categories are recommended, as reported in Table 2. + +**Table 2 – Sub-network demography classes** + +| Demography class | Typical population density (inhabitants/km 2 ) | Population range (inhabitants/km 2 ) | +|------------------|-----------------------------------------------------------|-------------------------------------------------| +| DU | 20 000 | >10 000 | +| Urban (U) | 2 000 | 1 000–10 000 | +| Suburban (SU) | 300 | 200–1 000 | + +**Table 2 – Sub-network demography classes** + +| Demography class | Typical population density (inhabitants/km 2 ) | Population range (inhabitants/km 2 ) | +|------------------|-----------------------------------------------------------|-------------------------------------------------| +| Rural (RU) | 30 | 20–200 | +| Unpopulated | 0 | <20 | + +Some references to databases where the demography distribution classes are reported can be found at [b-Eurostat], [b-UN] and [b-US CB]. + +#### 6.3.3 Topography + +The topography classes reported in Table 3 shall be used. + +**Table 3 – Sub-network topography classes** + +| Topography classification | | Examples | +|-------------------------------|--------------|----------------------| +| ETSI class | Median slope | | +| 1
Flat
(FAO 1-3) | 0–5% | Denmark, Netherlands | +| 2
Rolling
(FAO 4-6) | >5–30% | France, Italy | +| 3
Mountainous
(FAO 7-8) | >30% | Norway, Switzerland | + +Information on the median slope gradient distribution in the world can be found in the Food and Agriculture Organization (FAO) of the United Nations (UN) world median slope distribution information database [b-FAO-1]. + +#### 6.3.4 Climate zones + +The climate zones reported in Table 4 have been identified. + +**Table 4 – Sub-network climate classes** + +| Climate class | Subclass | Explanation | +|---------------------|---------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------| +| A: Tropical | Temperature of the coldest month: >18°C | | +| | Af | No dry season, at least 60 mm of rainfall in the driest month | +| | Am | Monsoon type, short dry season but sufficient moisture to keep ground wet throughout the year | +| | Aw | Distinct dry season, one month with precipitation < 60 mm | +| B: Dry | Arid regions where annual evaporation exceeds annual precipitation, marked dry season | | +| | Bs | Steppe climate | +| | Bs | Desert | +| C: Temperate | Average temperature of the coldest month < 18°C and > -3°C, and average temperature of the warmest month > 10°C | | + +**Table 4 – Sub-network climate classes** + +| Climate class | Subclass | Explanation | +|-----------------|---------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| | Cw | Winter dry season, at least 10 times as much precipitation in the wettest month of summer than in driest month of winter | +| | Cs | Summer dry season, at least 3 times as much rain in the wettest month of winter than in the driest month of summer; the latter having less than 30 mm precipitation | +| | Cf | At least 30 mm precipitation in the driest month; the difference between the wettest month and the driest month less than for Cw and Cs | +| D: Cold | Average temperature of the warmest month > 10°C and that of the coldest month < -3°C | | +| | Df | At least 30 mm of rain in the driest month; the difference between wettest month and the driest month less than for Cw and Cs | +| | Dw | At least 10 times as much precipitation in the wettest month of summer than in the driest month of winter | +| E: Polar | Average temperature of the warmest month < 10 °C | | +| | Et | Tundra, average temperature of the warmest month > 0°C | +| | Ef | No month with temperature > 10°C | + +The above reported climate classification is based on the FAO Koeppen classification [b-FAO-2]. It is recommended to use the five main classes A to E; the indication of the subclasses is optional. + +#### 6.3.5 Additional classification classes + +To properly select the sub-networks operators' penetration, ratio and data traffic types could be reported for information. Table 5 lists the classification based on the penetration rate and Table 6 lists the classification based on data volume (DV) thresholds. + +**Table 5 – Sub-network penetration classes** + +| Symbol | Operator penetration class | Range | +|--------|----------------------------|------------------| +| DP | Dominant penetration | >30% penetration | +| NDP | Non-dominant penetration | <30% penetration | +| MP | Minor penetration | <10% penetration | + +**Table 6 – Sub-network data volume classes** + +| Symbol | Traffic class | Specific thresholds | +|-----------------------------|--------------------------------|----------------------------------------------------------| +| Circuit switched (CS) | CS dominating | >50% of data volume is CS | +| Packed switched small (PSS) | PS – small packages dominating | >50% of data volume is PS,
>80% of packages are small | +| Packet switched large (PSL) | PS – large packages dominating | >50% of data volume is PS,
<80% of packages are small | + +## 7 Metrics for energy efficiency assessment + +### 7.1 Introduction + +The following metrics may be used to assess mobile network energy efficiency. + +### 7.2 Energy consumption metrics + +The energy consumption of the mobile network (ECMN) is the sum of the energy consumption of each piece of equipment included in the MN under investigation (see clause 6). The network EC is measured according to the assessment process defined in clause 8.3.1 such that individual metric values are provided per radio access technology (RAT) and per MNO. + +$$EC_{MN} = \sum_i (\sum_k EC_{BS_{i,k}} + EC_{SI_i}) + \sum_m EC_{cells} + \sum_j EC_{BH_j} + \sum_l EC_{RC_l} + \sum_l EC_{CC_l} + \sum_l EC_{LC_l} \quad (1)$$ + +where: + +*EC* is energy consumption; + +*BS* refers to the base stations in the MN under measurement; + +*BH* is the backhauling providing connection to the BSs in the MN under measurement (including transport); + +*SI* is the site infrastructure (e.g., rectifier, battery losses, climate equipment, tower mounted amplifier (TMA), tower illumination); + +*RC* is the control node(s), including all infrastructure of the RC site; + +*CC* is the central cloud, *LC* the local cloud entities, as defined in Figure 1; + +*i* is an index spanning over the number of sites; + +*j* an index spanning over the number of BH equipment connected to the *i* sites; + +*k* is the index spanning over the number of BSs in the *i*-th site; + +*l* is the index spanning over the control nodes of the MN; + +*m* is the number of small cells, local cells in the MN. + +$EC_{MN}$ shall be measured in Wh over the period of measurement *T* (see clause 8). + +NOTE 1 – If the control node(s) supports a larger MN than the one which is assessed, only a share of RC EC is considered proportional to the radio network controller (RNC) share of traffic that belongs to the MN being assessed. + +To allow for a more precise assessment of the EC impact of local factors (e.g., location specific site equipment), it is recommended to report, into the parameter $EC_{SI_i}$ , the measurement of the site equipment consumption into two classes: + +- 1) information communications technology (ICT) equipment (equipment directly needed to perform the telecommunication service); +- 2) support equipment (all equipment installed at the site which are needed to operate the particular site, but which are not directly needed for the telecommunication service, such as air-conditioning, backup power, lights). + +Moreover, it is also requested to classify the site equipment according to operational temperature range. + +Based on such a classification the following additional network key performance indicator (KPI) describing the EC of the TE with reference to the total EC is introduced: + +$$SEE = EC_{BSs} / (EC_{BSs} + EC_{SI}) \quad (1a)$$ + +The above metric gives an indication of site energy efficiency (SEE) in terms of the fraction of energy used for actual TE (see Figure 3). + +![Figure 3: Layout of a typical site to determine the SEE metric. The diagram shows two main equipment groups. The top group, 'Telecom equipment', contains a 'Base station' with 'RF', 'Baseband', and 'Backhaul' components, connected to 'Sector 1', 'Sector 2', and 'Sector i'. A 'Test point: Electrical power to Telecom equipment' is shown with an arrow pointing to the Base station. The bottom group, 'Site support equipment', contains 'Rectifier (AC/DC)', 'Power storage', 'Security lights, etc.', and 'Air conditioning'. A 'Test point: Electrical power to site' is shown with an arrow pointing to the Rectifier (AC/DC). A dashed line connects the two test points. The reference 'L.1331(20)_F03' is in the bottom right corner.](76b0cd79baaedd942af4dc42f2e764b8_img.jpg) + +Figure 3: Layout of a typical site to determine the SEE metric. The diagram shows two main equipment groups. The top group, 'Telecom equipment', contains a 'Base station' with 'RF', 'Baseband', and 'Backhaul' components, connected to 'Sector 1', 'Sector 2', and 'Sector i'. A 'Test point: Electrical power to Telecom equipment' is shown with an arrow pointing to the Base station. The bottom group, 'Site support equipment', contains 'Rectifier (AC/DC)', 'Power storage', 'Security lights, etc.', and 'Air conditioning'. A 'Test point: Electrical power to site' is shown with an arrow pointing to the Rectifier (AC/DC). A dashed line connects the two test points. The reference 'L.1331(20)\_F03' is in the bottom right corner. + +**Figure 3 – Layout of a typical site to determine the SEE metric** + +NOTE 2 – Power generation is not part of MN energy efficiency, but it is reported for informational use for total cost of ownership (TCO) and greenhouse gas (GHG) analysis. + +In currently deployed sites, there is a wide mixture of equipment installed within one room with different cooling requirements. The maximum room temperature is determined by the equipment with the lowest acceptable operating temperature. However, BS equipment is often designed to be operated at much higher temperatures. + +The installed site equipment is classified into different environmental groups based on their operational temperature range (see Table 7). Such a classification allows the assessment of the energy saving potential if the site is split into areas for equipment which require cooling and others which can operate without. + +**Table 7 – Environmental class categories for site equipment** + +| Environmental class | Temperature range | IP (ingress protection) code | +|---------------------|-------------------|------------------------------| +| A | 0 to 28 °C | IP23 | +| B | –20 to 40 °C | IP45 | +| C | –40 to 55 °C | IP45 | + +The energy sources available in the sites (e.g., power grid, generator set) shall be reported in the tables of clause 10 based on the typical layout reported in Figure 4 (where the notion of "extended telecommunication site" has been included to also include the on-site electricity generation and the "\*" makes reference to the Telecommunication site as in Figure 3). + +![Figure 4 – Schematic representation of the energy sources for a site. The diagram shows a flow from a 'Utility (grid) power plant' on the left to an 'Extended Telecom site' on the right. The 'Utility (grid) power plant' contains 'Renewable' and 'Non-renewable' sources. An arrow points from the plant to a dashed box labeled 'Test point: Electrical power from grid'. From this box, an arrow points to the 'Extended Telecom site'. The 'Extended Telecom site' contains 'Telecom site*', 'Renewable', 'Non-renewable', and 'On-site electricity generation'. Below the diagram is the text 'L.1331(22)_F04'.](9c6461e1e94afae4dec455e69a2ce152_img.jpg) + +Figure 4 – Schematic representation of the energy sources for a site. The diagram shows a flow from a 'Utility (grid) power plant' on the left to an 'Extended Telecom site' on the right. The 'Utility (grid) power plant' contains 'Renewable' and 'Non-renewable' sources. An arrow points from the plant to a dashed box labeled 'Test point: Electrical power from grid'. From this box, an arrow points to the 'Extended Telecom site'. The 'Extended Telecom site' contains 'Telecom site\*', 'Renewable', 'Non-renewable', and 'On-site electricity generation'. Below the diagram is the text 'L.1331(22)\_F04'. + +**Figure 4 – Schematic representation of the energy sources for a site** + +The estimation of the environmental impact from the EC requires additional parameters (e.g., GHG emissions or impact on the power grid dimensioning). Power consumption and power supply measurements/reports include: + +- total electrical EC of the site; +- total electrical EC of the ICT equipment; +- total electrical energy supplied from the grid; +- peak power delivered from the grid; +- total energy supplied in a form other than electricity; +- total amount of energy generated at the site, separated between production type (e.g., generator set, solar, wind, fuel cell); +- total site energy storage capacity; +- peak shaving features available at the site. + +The EC of the central and local cloud is measured in Wh over the period $T$ . For a virtualized environment, the measurement procedure for energy efficiency is described in the [b-ETSI EN 303 471]. + +### 7.3 Performance metrics + +#### 7.3.1 Capacity (data volume) + +The MN performance metrics are derived from parameters of the MN under investigation (see clause 6) relevant to energy efficiency, in particular, the total data volume of the mobile network ( $DV_{MN}$ ) delivered by all its equipment and its global coverage area ( $CoA_{MN}$ ). + +For packet switched services, $DV_{MN}$ is defined as the data volume delivered by the equipment of the mobile network under investigation during the time frame $T$ of the EC assessment. The assessment process defined in clause 8 shall be used. + +$$DV_{MN-PS} = \sum_{i,k} DV_{BS_{i,k}-PS} \quad (2)$$ + +where $DV$ , measured in bits, is the performance delivered in terms of data volume in the network over the measurement period $T$ (see clause 8); $i$ and $k$ are defined in Equation (1). + +For CS services such as voice, $DV_{MN-CS}$ is defined as the data volume delivered by the equipment of the mobile network under investigation during the time frame $T$ of the EC assessment. + +$$DV_{MN-CS} = \sum_{i,k} DV_{BS_{i,k}-CS} \quad (3)$$ + +where $DV$ , measured in bits, is the performance delivered in terms of data volume in the network over the measurement period $T$ (see clause 8); $i$ and $k$ are as defined in Equation (1). + +Note that "circuit switched" means here all voice services, interactive services and video services managed by the MNOs, including CS voice, voice over LTE (VoLTE) and real-time video services delivered through dedicated bearers. The assessment process defined in clause 8 shall be used. + +The overall data volume is computed as follows: + +$$DV_{MN} = DV_{MN-PS} + DV_{MN-CS} \quad (4)$$ + +$DV_{MN}$ can be derived from standard counters defined in [ETSI TS 132 425] and [ETSI TS 132 412] for LTE or equivalent used for 2G and 3G, multiplying by the measurement duration $T$ . The counters (in [ETSI TS 132 425] and [ETSI TS 132 412]) also account for the quality of service (QoS) being reported in the QoS class identifier (QCI) basis (see [ETSI TS 123 203]). For 5G the DV can be derived from ETSI TS 128.552/TS128.554, by measuring amount of DL/UL PDCP SDU bits of the considered network elements over the measurement period. + +NOTE 1 – $DV_{MN}$ includes data volumes for downlink (DL) and uplink (UL). + +NOTE 2 – BH supervision and control data volumes are not considered (in order to include only the payload). + +$DV_{MN}$ is expressed in bits. + +#### 7.3.2 Coverage area + +Coverage area ( $CoA_{MN}$ ) is also considered a mobile network performance metric in the MN designed primarily for coverage goals (and hence especially in RU environments). The assessment process defined in clause 8 shall be used. Coverage area is expressed in $m^2$ . + +#### 7.3.3 Latency + +Latency is considered additionally for MN where ultra-reliable low latency communication (URLLC) use cases predominate. Latency is measured in [ms]. Within the definition of E2EE latency, only the user plane latency is considered, being more relevant in terms of application performance of the network under test. The definitions of latency are based on [ITU-R M.2410]. + +For measurement purposes the UP latency is: + +$$T_{e2e;MN} = 2 * (T_r + T_b + T_c + T_t) \quad (5)$$ + +where: + +- $T_{e2e;MN}$ is the end-to-end user plane latency. +- $T_r$ is the latency introduced by the radio part, according to Figure 5, namely the packet transmission time between BSs and UEs, and is mainly due to physical layer communication. +- $T_b$ is the latency introduced by the backhaul part, according to Figure 5, namely the time for building connections between BSs and the core network. +- $T_c$ is the latency introduced by the core part, according to Figure 5, namely the processing time in the core network. +- $T_t$ is the latency introduced by the transport part, according to Figure 5, namely the delay for the data to be sent from the core network to the Internet/cloud. + +![Figure 5: Definition of the end-to-end user plane latency components. The diagram shows a horizontal timeline with four main components: a smartphone icon on the left, a 'BS site' box containing 'BS equipment' and 'Site equipment', a server and database icon, and a 'Central cloud' cloud icon on the right. Below the timeline, four latency components are labeled: T_r (between smartphone and BS site), T_b (between BS site and server), T_c (between server and Central cloud), and T_t (between Central cloud and smartphone). The text 'L.1331(20)_F05' is in the bottom right corner.](5b8a756d9a71c35f17db8bcb90b438a3_img.jpg) + +Figure 5: Definition of the end-to-end user plane latency components. The diagram shows a horizontal timeline with four main components: a smartphone icon on the left, a 'BS site' box containing 'BS equipment' and 'Site equipment', a server and database icon, and a 'Central cloud' cloud icon on the right. Below the timeline, four latency components are labeled: T\_r (between smartphone and BS site), T\_b (between BS site and server), T\_c (between server and Central cloud), and T\_t (between Central cloud and smartphone). The text 'L.1331(20)\_F05' is in the bottom right corner. + +**Figure 5 – Definition of the end-to-end user plane latency components** + +#### 7.3.4 Massive machine type networks + +The number of subscribers registered to the network is the metric used in case of MMTC networks or network slices. + +## 7.4 Mobile network energy efficiency metrics + +Mobile network data energy efficiency ( $EE_{MN,DV}$ ) is the ratio between the data volume ( $DV_{MN}$ ) and the energy consumption ( $EC_{MN}$ ) when assessed during the same time period. + +$$EE_{MN,DV} = \frac{DV_{MN}}{EC_{MN}} \quad (6)$$ + +where $EE_{MN,DV}$ is expressed in bit/J. + +Mobile network coverage energy efficiency ( $EE_{MN,CoA}$ ) is the ratio between the area covered by the MN under investigation (see clause 6) and the EC when assessed for one year. $EE_{MN,CoA}$ is mainly used to complement $EE_{MN,DV}$ for MNs handling low data volumes, in particular in rural or deep rural areas. The area covered shall be assessed using rules (i.e., derived from geographic data or propagation models) defined in clause 8: + +$$EE_{MN,CoA} = \frac{CoA\_des_{MN}}{EC_{MN}} \quad (7)$$ + +where $EE_{MN,CoA}$ is expressed in $m^2/J$ and $EC_{MN}$ is the yearly energy consumption and $CoA\_des_{MN}$ is the "coverage area" as defined in clause 8.3.3. + +Latency based metric is the inverse ratio of the end-to-end user plane latency and the energy consumed by the MN. + +$$EE_{MN,L} = \frac{1}{T_{eze,MN} * EC_{MN}} \quad (8)$$ + +where $EE_{MN,L}$ is expressed in $ms^{-1}/J$ . + +In case of MMTC networks the metric for EE is as follows: + +$$EE_{MN,MMTC} = \frac{N_{MMTC}}{EC_{MN}} \quad (9)$$ + +For networks with Network Slicing (NS) functionalities the EE is measured as follows (ETSI TS 128.554[14]): + +$$\text{Generic network slice EE KPI} = \frac{\text{Performance of network slice } (P_{ns})}{\text{Energy Consumption of network slice } (EC_{ns})} \quad (10)$$ + +where the performance $P_{ns}$ is related to the type of NS implemented in the network: + +$$\begin{aligned} P_{ns} &= DV_{mn} \text{ for the eMBB NS type} \\ P_{ns} &= \frac{1}{T_{eze,MN}} \text{ for the URLLC NS type} \\ P_{ns} &= N_{MMTC} \text{ for the MMTC NS type} \end{aligned}$$ + +## 8 Measurement of energy efficiency + +### 8.1 Introduction + +The measurement of the $EE_{MN}$ in the MN under investigation is based on the separate measurement of the performance (in terms of capacity and coverage) and energy, according to the metrics defined in clause 7. + +### 8.2 Time duration of the measurement + +The time duration of the measurement, denoted $T$ , shall be one of the alternatives: + +- One week (7 days); +- One month (30 days); +- One year (365 days). + +The minimum duration is therefore one week: monthly and yearly measurements are extensions of the basic weekly test. For the CoA metric the EC shall always be extrapolated to a one-year time period. It is noted that $T$ does not correspond to a granularity time or a repetition of the measurement time, which are optional values to be reported in clause 10 tables. + +### 8.3 Measurement procedures + +#### 8.3.1 Measurement of energy consumption + +The energy consumption of the MN can be measured by means of metering information provided by utility suppliers or by mobile network integrated measurement systems. Moreover, sensors can be used to measure site and equipment EC, following the requirements set by [ES 202 336-12]. + +The $EC_{MN}$ is based on site granularity and therefore includes all the equipment installed in the MNO sites (including the network controllers whenever applicable). The $EC_{MN}$ shall be differentiated per MNO providing service to the MN; in cases of shared infrastructure the $EC_{MN}$ of the shared sites shall be computed per MNO sharing those sites, referring to the commercial agreements or best practices between MNOs. In case of separate metering per MNO the respective part of the $EC_{MN}$ shall be assigned to each MNO. + +The $EC_{MN}$ shall be based on a per RAT estimation. If the sites contain BSs of different RATs the $EC_{MN}$ shall be measured for each RAT. + +The list of equipment operating in the MN sites under investigation shall be reported in the assessment report, including cooling, power conversion, etc. For a site with multi RAT equipment the EC of that equipment shall be split between each RAT proportionally to the configured radio frequency (RF) power transmitted by each RAT; further details on the multi RAT will be issued according to the development of multi RAT measurement in [b-ETSI ES 202 706-1]. + +The frequency of reporting shall be determined to guarantee the most accurate estimation of the consumption per RAT and per MNO and should take into account the energy provider billing procedures, the MN performance assessment process and the MN integrated measurement system (if available and if compliant with [ETSI ES 202 336-12]). The choice of the reporting frequency shall be documented in the assessment report. + +#### 8.3.2 Measurement of capacity + +The $DV_{MN}$ is measured using network counters for data volume related to the aggregated traffic in the set of BSs considered in the MN under test. + +For packet switched (PS) traffic, the data volume is considered the overall amount of data transferred to and from the users connected to the MN under test. Data volume is measured in an aggregated way for each RAT present in the MN. + +For CS traffic (e.g., CS voice or VoLTE), the data volume is considered the number of minutes of communications during the time $T$ multiplied by the data rate of the corresponding service and the call success rate. The call success rate is equal to 1 minus the sum of blocking and dropping rates: + +$$\text{Call Success Rate} = (1 - \text{dropping rate}) \times 100 [\%] \quad (11)$$ + +The dropping includes the intracell call failure (rate of dropping calls due to all causes not related to handover) and the handover failure: + +$$1 - \text{dropping rate} = (1 - \text{intracell failure rate})(1 - \text{handover failure rate}) \quad (12)$$ + +In order to include reliability in the measurement, the aggregated data volume shall be provided together with the 95th percentile of the cumulative distribution, for each RAT in the MN. + +NOTE 1 – It is not possible for data services to determine a user related QoS, i.e., to identify for each data connection if a target throughput has been reached using counters. Such a computation, requiring the usage of probes, is out of scope of this Recommendation. + +NOTE 2 – As soon as the minimization of drive test (MDT) related measurements in [ETSI TS 136 314] are available the data volume may be measured according to the specification given therein (especially referring to clause 4.1.8 in [ETSI TS 136 314]). + +#### 8.3.3 Determination of coverage area + +##### 8.3.3.1 Introduction + +The coverage area is closely linked to network planning and intended services delivered within a certain geographical area. These parameters vary according to an MNO strategy and might therefore differ from MNO to MNO but also within the network of one MNO for different geographical areas. + +In order to have simple tests, for the sake of energy efficiency assessment, drive tests and similar additional measurement campaigns are not required. + +The coverage area is described by the following parameters: + +- The total geographical area of a country (CoA\_geo). This includes the total geographical area which falls into the network operators' responsibility (total network and/or sub-area under investigation). A network might cover the geographical area only to a certain fraction (often defined by the licence agreements, e.g., area coverage of a complete country or of a region). +- The designated coverage area (CoA\_des). This is the area in which network coverage is provided by the selected sub-network and it is derived by planning models from network design, planned service and geographical data. +- a coverage quality factor (CoA\_qdes). This factor takes into account measured feedback from user equipment (as described in Tables 8-1 to 8-3). This coverage quality factor highlights possible drops in network performances due, for example, to coverage issues (e.g., inside buildings), load congestion or significant interference effects. + +##### 8.3.3.2 Geographic coverage area + +The geographic coverage area is the total two-dimensional area of a country, region or city where the MNO under test provides its service according to licence agreements. This area might be not completely covered by the network. A licence agreement might include a geographic coverage area (for example, > 90% of the country area is covered) and an additional population coverage area (for example, 98% of the population is covered). + +##### 8.3.3.3 Designated coverage area + +The designated coverage area is the area to be covered based on network planning and presents the actual geographical area where the operator officially promises coverage. This area is defined by the MNO's network service plan where the coverage, according to its licence agreement or similar, is delivered. The area (sometimes referred to as "best server" area), is based on BS power, propagation + +conditions in the selected area, accepted outage criteria and considered planning models (and therefore are hardly comparable). + +The designated coverage area also includes in-building coverage. Only the footprint of the building is considered the in-building area (e.g., in multistory buildings), rather than the buildings' actual floor space. + +##### 8.3.3.4 Coverage quality + +The actual coverage area where user equipment (UE) can be served might differ from the originally designated coverage area (i.e., false coverage zones within the considered area). The coverage quality factor measures the performances of the network within the actually covered fraction of the planned total coverage area. UE reports such as failed call attempts (see Tables 8-1 to 8-3) are used to determine how well the users within the coverage area are covered. + +The coverage quality indicator is provided for network efficiency result evaluations. It is linked to network quality and has to be defined in relation to QoS definitions. + +A coverage map based on signal quality, such as the signal to interference plus noise ratio (SINR) as shown in Figure 6, could be used to determine the fraction of the total area where a signal quality above a certain minimum value is achieved. However, such maps require a large number of field measurements. + +![Figure 6: Typical SINR distribution of a mobile network. The figure shows a map of a hexagonal area with a color-coded SINR distribution. The color scale ranges from green (low SINR) to red (high SINR). The map shows a complex pattern of green and yellow areas, with some red spots indicating higher SINR values. A legend at the bottom indicates the SINR Strength (dB) scale: -10 to -8 (green), -8 to -6 (yellow), -6 to -4 (orange), and -4 to -2 (red).](a1a474be12b8992842992294b1d18592_img.jpg) + +Figure 6: Typical SINR distribution of a mobile network. The figure shows a map of a hexagonal area with a color-coded SINR distribution. The color scale ranges from green (low SINR) to red (high SINR). The map shows a complex pattern of green and yellow areas, with some red spots indicating higher SINR values. A legend at the bottom indicates the SINR Strength (dB) scale: -10 to -8 (green), -8 to -6 (yellow), -6 to -4 (orange), and -4 to -2 (red). + +**Figure 6 – Typical SINR distribution of a mobile network** + +For the sake of an energy efficiency assessment, it is not required to have knowledge of detailed network conditions such as actual coverage gap locations. From an energy efficiency assessment point of view, it is important to estimate the percentage of users/sessions or served users/sessions experiencing technical problems within the considered area. + +This allows a number of simplifications and an indirect determination of a quality factor. + +The coverage quality factor shall be measured based on coverage failures reported by the appropriate network counters (see Tables 8 to 10): + +$$\text{CoA\_Qdes} = 1 - \text{"percentage of users/sessions with coverage failure"} \quad (13)$$ + +The following indicators shall be used to calculate the coverage failure (for details, see Tables 8-1 to 8-3): + +- Radio resource control (RRC) setup failure ratio (call setup failure ratio); +- Radio access bearer (RAB) setup failure ratio (UE-BS radio interface failure); +- RAB release failure ratio (UE-BS radio interface failure). + +An additional factor which can indicate a coverage issue is the handover drop rate. However, a handover drop can have multiple reasons (e.g., cell overload, UE speed). Furthermore, the handover drop rate depends on the network structure (number of neighbouring cells). Its calculation requires several additional network parameters and significantly complicates the data collection and analysis. This factor is therefore omitted. + +The coverage quality factor for a site is defined as follows: + +$$\begin{aligned} \text{CoA\_Qdes} = & (1 - \text{RRC setup failure ratio}) (1 - \text{RAB setup failure ratio}) \\ & (1 - \text{RAB release failure ratio}) \end{aligned} \quad (14)$$ + +The parameters needed are specified by 3G (mobile) partnership project (3GPP) standards and the results can be obtained from the network management and supervision. + +The failure ratios are the fraction of failures of the total number of attempts: + +- RRC setup failure ratio = $(\sum_k \text{Failed RRC connection establishment } s_k) / (\sum_k \text{attempted RRC connection establishment } s_k)$ ; +- RAB setup failure ratio = $(\sum_k \text{RAB setup failure}_k) / (\sum_k \text{RAB setup attempted}_k)$ ; +- RAB release failure ratio = $(\sum_k \text{RAB release failure}_k) / (\sum_k \text{RAB release attempted}_k)$ , + +where $k$ is the index spanning over the number of BSs in the considered site. + +Tables 8, 9 and 10 report the measurement parameters required for coverage quality calculation. For LTE, see Table 8 (refer to [ETSI TS 132 425] for definition/source), for UMTS, see Table 9 (refer to [ETSI TS 132 405]) and for GSM, see Table 10 (refer to [ETSI TS 152 402]). + +**Table 8 – Measurement parameters required for coverage quality calculation for LTE** + +| Parameter | Function | Counter name | +|---------------------------------------|------------------------|-----------------------------------| +| RRC connection establishment failures | Radio resource control | RRC.ConnEstabFail. sum | +| RRC connection establishment attempts | Radio resource control | RRC.ConnEstabAtt. sum | +| E-RAB setup failures | Initial E-RAB setup | ERAB.EstabInitFailNbr. sum | +| | Additional E-RAB setup | ERAB.EstabAddFailNbr. sum | +| E-RAB setup attempts | Initial E-RAB setup | ERAB.EstabInitAttNbr. sum | +| | Additional E-RAB setup | ERAB.EstabAddAttNbr. sum | +| E-RAB release failures | E-RAB release | ERAB.RelFailNbr. sum | +| E-RAB release attempts | E-RAB release | ERAB.RelAttNbr. sum | + +**Table 9 – Measurements parameters required for coverage quality calculations for UMTS** + +| Parameter | Function | Counter name | +|---------------------------------------|-------------------------|------------------------------------------------------------------------------| +| RRC connection establishment failures | Radio resource control | RRC.FailConnEstab. sum | +| RRC connection establishment attempts | Radio resource control | RRC.AttConnEstab. sum | +| RAB setup failures | RAB setup for CS domain | RAB.FailEstabCSNoQueuing. sum ,
RAB.FailEstabCSQueuing. sum | +| | RAB setup for PS domain | RAB.FailEstabPSNoQueuing. sum
RAB.FailEstabPSQueuing. sum | +| RAB setup attempts | RAB setup for CS domain | RAB.AttEstabCS.Conv.
RAB.AttEstabCS.Strm | + +**Table 9 – Measurements parameters required for coverage quality calculations for UMTS** + +| Parameter | Function | Counter name | +|----------------------|---------------------------|---------------------------------------------------------------------------------------------------| +| | | RAB.AttEstabCS.Intact
RAB.AttEstabCS.Bgrd | +| | RAB setup for PS domain | RAB.AttEstabPS.Conv
RAB.AttEstabPS.Strm.
RAB.AttEstabPS.Intact
RAB.AttEstabPS.Bgrd | +| RAB release failures | RAB release for CS domain | RAB.FailRelCS.sum | +| | RAB release for PS domain | RAB.FailRelPS.sum | +| RAB release attempts | RAB release for CS domain | RAB.AttRelCS.sum | +| | RAB release for PS domain | RAB.AttRelPS.sum | + +**Table 10 – Measurement parameters required for coverage quality calculations for GSM** + +| Parameter | Function | Counter name | +|-------------------------------|----------------------|--------------------------| +| Immediate assignment success | IMMEDIATE ASSIGNMENT | succImmediateAssingProcs | +| Immediate assignment attempts | IMMEDIATE ASSIGNMENT | attImmediateAssingProcs | + +The following averaging procedure is then used to obtain an average coverage quality factor of the partial network under test: + +$$CoA\_Qdes_{MN} = \sum_i \text{ } \llbracket CoA\_Qdes \rrbracket \_ (S\_i) DCA_{S_i} / \sum_i DCA_{S_i} \quad (15)$$ + +where: + +$S$ refers to the sites in the MN under measurement; + +$i$ is an index spanning over the number of sites. + +To avoid over-counting, the 'designed coverage' area should be defined as the area where the signals from the cells located in that area are stronger than the signals from cells in adjacent areas. It holds true that: + +$$CoA\_des_{MN} = \sum_i DCA_{S_i} \leq CoA\_geo \quad (16)$$ + +where: + +$S$ refers to the sites in the MN under measurement + +$i$ is an index spanning over the number of sites. + +#### 8.3.4 Measurement of latency + +Latency is measured using the following step-based approach (only latency in MN is considered, not in direct communications modes): + +- Step 0: Transmitter processing delay at BS; +- Step 1: Frame alignment; +- Step 2: Synchronization; + +- Step 3: Number of transmission time intervals (TTIs) used for data packet transmission (unloaded condition is assumed); +- Step 4: Hybrid automatic repeat request (HARQ) retransmission (assuming 10% error probability); +- Step 5: Receiver processing delay in UE. + +If the E2E latency KPI as defined in clause 6.3.1.0 of [ETSI TS 128 554] is available, that KPI shall be used for the metric of latency in this context. + +#### 8.3.5 Measurement of the number of subscribers + +The N\_MMTC is measured according to the definition reported in ETSI TS 128.554 clause 6.7.2.4.1. + +## 9 Extrapolation for overall networks + +### 9.1 Extrapolation approach + +The energy efficiency (EE) measured according to clauses 7 and 8 can be extrapolated to larger networks, as shown in Figure 7. When such an extrapolation is performed, it shall follow the method presented in this clause. + +The sub-network data is extrapolated to overall/total networks according to demography, topography and climate classifications, as described in clause 6. + +The extrapolation is done according to statistical information that indicates how recurrent the sub-network is within the total network to be addressed. + +![Figure 7: Extrapolation from one sub-network to a set of sub-networks ('total' network). The diagram shows a single sub-network on the left being expanded into a 'total' network on the right. The sub-network consists of a central RC (Radio Controller) connected to three 'Backhaul equipment' units. Each 'Backhaul equipment' is connected to a 'Site (wide area BS)', which contains a 'Base station' and 'Site equipment'. Each 'Site (wide area BS)' is further connected to two 'Local area BS' units. The 'total' network on the right is a stack of three identical sub-networks, indicating that the single sub-network is being extrapolated to a larger set of sub-networks. A large arrow points from the single sub-network to the stack of sub-networks. The text 'L.1331(20)_F07' is visible in the bottom right corner of the diagram.](15e4a144a88176b71ea3eff2722253b0_img.jpg) + +Figure 7: Extrapolation from one sub-network to a set of sub-networks ('total' network). The diagram shows a single sub-network on the left being expanded into a 'total' network on the right. The sub-network consists of a central RC (Radio Controller) connected to three 'Backhaul equipment' units. Each 'Backhaul equipment' is connected to a 'Site (wide area BS)', which contains a 'Base station' and 'Site equipment'. Each 'Site (wide area BS)' is further connected to two 'Local area BS' units. The 'total' network on the right is a stack of three identical sub-networks, indicating that the single sub-network is being extrapolated to a larger set of sub-networks. A large arrow points from the single sub-network to the stack of sub-networks. The text 'L.1331(20)\_F07' is visible in the bottom right corner of the diagram. + +**Figure 7 – Extrapolation from one sub-network to a set of sub-networks ("total" network)** + +The layout of the partial networks should be as reported in Figure 1, here simplified. + +### 9.2 Extrapolation method + +#### 9.2.1 Introduction of extrapolation method + +In case the overall/total area to be addressed is not completely known in terms of demographical, topographical or climatological composition, or if the measurements of clause 7 and clause 8 are executed in some but not all the sub-networks, then the results shall be presented according to the tables in clause 10. + +In such a case, an indication is needed for each sub-network of its percentage recurrence with respect to the total network, in terms of demographical, topographical and climatological composition. Otherwise, if the exact composition of the area is completely known, then the extrapolation shall be made to achieve the information valid for the total network. + +- The extrapolation procedure shall be based on the demographic information classes as reported in Table 2. It is optional to also make an extrapolation based on topography classes (Table 3) or on climate classes (Table 4) or on a combination of demography, topography and climate zones. +- The extrapolation shall be based on a demographic number of classes representing at least 75% of the total network area's demographic distribution. + +The following clauses show how to obtain data on the statistical distribution of demography, topography and climate zone classes in the networks under test at a total level. This information is to be used as a reference for every network area where this Recommendation will be used. + +#### 9.2.2 Statistical information about demography + +An example of demographical information for Europe can be found in [ETSI TS 132 425], showing how to classify the sub-network under test under a demography class as in Table 2. + +Another example, referring to UN information, is in [ETSI TS 132 412]. A further example for the USA can be found in [ETSI TS 123 203]. + +#### 9.2.3 Statistical information about topography + +An example of topographical information can be found at the FAO world median slope distribution information, to classify the sub-network under test under a demography class as in Table 3. + +#### 9.2.4 Statistical information about climate zones + +An example of topographical information can be found in the FAO Koeppen classification [b-FAO-2], which is used to classify the sub-network under test under a demographical class as in Table 4. + +### 9.3 Extrapolation reporting tables + +#### 9.3.1 Introduction of extrapolation reporting tables + +Table 11 indicates how to report the data for extrapolation towards the total EE based on demography only. This is the recommended approach when extrapolation data are computed. Not all the classes are measured, only those classes that allow a coverage of at least 75% of the whole demographical distribution of the total area under measurement. + +For all the sub-networks, the results of EE are reported according to the tables in clause 10 and the relative class shall be indicated. For all the same class measurements, an average of EE measurements shall be reported in Table 11; this shall be done both for data volume EE and for coverage area EE, whichever metric is used. + +Then, for each class an average EE shall be computed as follows: + +$$EE_{class,av} = \frac{\sum_k EE_{MN,k}}{K} \quad (17)$$ + +where "class" stands for one of the demography classes (DU, U, SU, RU or unpopulated) and $k$ is an index that runs over the number $K$ of sub-networks per class. + +The total EE should be computed as a weighted sum of all the averages available, the weights being the percentage of each demography class versus the sum of the available class's percentages. These percentages shall be derived from the information according to the examples of clause 9.2. + +Then the total EE shall be computed as follows: + +$$EE_{total} = \frac{\sum_m PofP_m EE_{class,av,m}}{\sum_m PofP_m} \quad (18)$$ + +where $PofP_m$ is the percentage of presence of the $m$ -th demography class in the network under test, $m$ is an index spanning over the number of classes and $EE_{class,av,m}$ is the $m$ -th average as computed in Equation (18). + +#### 9.3.2 Reporting extrapolation based on demography + +The reporting extrapolation method based on demography is summarized in Table 11. + +**Table 11 – Reporting extrapolation based on demography** + +| Demography classification | Percentage of presence (PofP) in the total network area of the class | $EE_{MN}$ in the class | | +|---------------------------|----------------------------------------------------------------------|------------------------|------------------| +| | | $EE_{MN,DV}$ | $EE_{MN,CoA}$ | +| DU | $PofP_{DU} [\%]$ | $EE_{DU,av}$ | $EE_{DU,av}$ | +| Urban (U) | $PofP_U [\%]$ | $EE_{U,av}$ | $EE_{U,av}$ | +| Suburban (SU) | $PofP_{SU} [\%]$ | $EE_{SU,av}$ | $EE_{SU,av}$ | +| Rural (RU) | $PofP_{RU} [\%]$ | $EE_{RU,av}$ | $EE_{RU,av}$ | +| Unpopulated | $PofP_{Unp} [\%]$ | $EE_{Unp,av}$ | $EE_{Unp,av}$ | +| Total EE | | $EE_{total,DV}$ | $EE_{total,CoA}$ | + +A demography table is the recommended extrapolation representation. In cases where the topography and climate zone classifications are available for the sub-networks measured according to clause 10, Table 12 and Table 13 are also to be reported. + +#### 9.3.3 Reporting extrapolation based on topography + +The reporting extrapolation method based on topography is summarized in Table 12. + +**Table 12 – Reporting extrapolation based on topography** + +| Topography classification | Percentage of presence (PofP) in the total network area of the class | $EE_{MN}$ in the class | | +|---------------------------|----------------------------------------------------------------------|------------------------|------------------| +| | | $EE_{MN,DV}$ | $EE_{MN,CoA}$ | +| 1 Flat (FAO 1–3) | $PofP_{Flat} [\%]$ | $EE_{Flat,av}$ | $EE_{Flat,av}$ | +| 2 Rolling (FAO 4–6) | $PofP_{Roll} [\%]$ | $EE_{Roll,av}$ | $EE_{Roll,av}$ | +| 3 Mountainous (FAO 7–8) | $PofP_{Mount} [\%]$ | $EE_{Mount,av}$ | $EE_{Mount,av}$ | +| Total EE | | $EE_{total,DV}$ | $EE_{total,CoA}$ | + +#### 9.3.4 Reporting extrapolation based on climate zones + +The reporting extrapolation method based on climate zones is summarized in Table 13. + +**Table 13 – Reporting extrapolation based on climate zones** + +| Climate zone classification | Percentage of presence (PofP) in the total network area of the class | $EE_{MN}$ in the class | | +|-----------------------------|----------------------------------------------------------------------|------------------------|------------------| +| | | $EE_{MN,DV}$ | $EE_{MN,CoA}$ | +| A Tropical | PofP Trop % | $EE_{Trop,av}$ | $EE_{Trop,av}$ | +| B Dry | PofP Dry % | $EE_{Dry,av}$ | $EE_{Dry,av}$ | +| C Temperate | PofP Temp % | $EE_{Temp,av}$ | $EE_{Temp,av}$ | +| D Cold | PofP Cold % | $EE_{Cold,av}$ | $EE_{Cold,av}$ | +| E Polar | PofP Polar % | $EE_{Polar,av}$ | $EE_{Polar,av}$ | +| Total EE | | $EE_{total,DV}$ | $EE_{total,CoA}$ | + +## 10 Assessment report + +### 10.1 Introduction of the assessment report + +The results of the assessments shall be reported accurately, clearly, unambiguously and objectively, and in accordance with any specific instructions in the required method(s). + +The report shall include tables defined in clauses 10.2 to 10.4. Items in italics can be considered optional. + +Further guidelines on the test report can be found in clause 5.10 of [ISO/IEC 17025]. + +### 10.2 Report on the network area under test + +Table 14 reports the details of the network area under test, representing a sub-network where the measurements are conducted. The network area is the area encompassing all of the sites under measurement; the $CoA_{des_{MN}}$ is instead computed starting from the area covered by each site (per clause 8) and aggregating for all the sites in the network area under test. + +For each site reported in Table 14, the details shall be included in Table 15. Table 16 reports the measurement results for each site. + +**Table 14 – Report of network area under test** + +| Network area under test | | +|-----------------------------------------------------------------------|-----------------------------------------------------------------| +| Demography class
[DU, urban, suburban, rural, sparse]
[Table 2] | | +| Topography class [Table 3] | | +| Climate zone [Table 4] | | +| Informative classification [Tables 5 and 6] | | +| Network area definition
[by demography, by geography, by topology] | | +| | Number of inhabitants in the network area
[estimate] | +| | Network area dimensions
[estimate, km 2 ] | + +**Table 14 – Report of network area under test** + +| Network area under test | | | +|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------|--| +| | Number of sites in the network area
[same RCs?] | | +| Type of sites in the network area | | | +| | Number of wide area BS sites | | +| | Number of medium range BS sites | | +| | Number of other sites/equipment
(local area BS, relay nodes, etc.) | | +| Site categorization | | | +| | Number of sites in an MNO
local exchange premise | | +| | Number of sites in buildings not owned by
MNO | | +| | Number of sites in a shelter | | +| | Number of any other sites | | +| Multi-MNO sites | | | +| | Number of “single MNO” sites | | +| | Number of co-located multi-MNOs sites | | +| | Number of sites in “network sharing”
mode | | +| Multitechnology sites | | | +| | Number of 2G-only sites | | +| | Number of 3G-only sites | | +| | Number of LTE-only sites | | +| | Number of 2G+3G sites | | +| | Number of 5G sites | | +| | Other options [indicate] | | +| Backhauling information | | | +| | Predominant type of backhauling
[wireless, fibre, copper...] | | +| | Number of backhauling links per type | | +| Energy efficiency in the network area | | | +| | EE MN,DV [b/J] | | +| | EE MN,CoA [m 2 /J] | | +| | EE MN,L [ms -1 /J] | | +| | EE MN,MMTC [J -1 ] | | +| Energy efficiency top-down approach results (see note) | | | +| NOTE – If any alternative EE approach has been conducted on the network under test (i.e., measuring the aggregated EC and the aggregated data volume or coverage area) the results of the evaluation shall be reported here for comparison purposes. | | | + +### 10.3 Report of sites under test + +**Table 15 – Report of sites under test** + +| Site(s) under test in the network area
(one table per site type to be measured in the network area) | | | +|----------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------|--------------------| +| Measurement duration | | | +| | Time duration of the measurement [T] | | +| | Measurement start date and time | | +| | Measurement finish date and time | | +| | Repetition time | | +| | Granularity of measurements | | +| Type of site | | | +| | Site "layer"
[wide area, medium range, other]
In case of wide area, indicate number of sectors and carriers per sector | | +| | Site "technology"
[2G, 3G, 2G+3G, LTE only, 2G+3G+LTE, 5G, other] | | +| | Site "MNOs"
[single MNO, co-location, network sharing, other] | | +| Site and equipment age | | | +|
  • Initial commission date of the site
  • Commission date of the current equipment in the site
| | | +| Temperature | Internal °C | External °C | +|
  • Average temperature [over period T]
  • Minimum temperature
  • Maximum temperature
| | | +| Environmental class Temp. range
IC class (for each equipment in the site) | | | +| A 0 ... 28 °C
B -20 ... 40 °C
C -40 ... 55 °C
IP class | | | +| Site infrastructure | | | +| | Site location
[local exchange premises, building, shelter, other] | | +| | Site composition | | +| |
  • Air conditioners
| | +| |
  • Rectifiers/batteries
| | +| |
  • Fixed network equipment consumption
| | +| |
  • Other
| | + +**Table 15 – Report of sites under test** + +| Site(s) under test in the network area
(one table per site type to be measured in the network area) | | | +|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------|--| +| | Estimated percentage of infrastructure consumption in the site (EC_{si}) | | +| EC of ICT equipment in the site [Wh] | | | +| EC of all the support equipment in the site [Wh] | | | +| Energy efficiency in the site equipment
(Energy_ICTequipment /
Energy_Total_network) | | | +|
  • – Total electrical energy supplied from the grid
  • – Peak power delivered from the grid
  • – Total site energy storage capacity
  • – Peak shaving features available at the site
| | | +| Energy efficiency enhancement methods affecting the site equipment during the test | | | +| Estimated percentage of presence of this site type in the network area | | | +| Electricity sources used in the site | | | +| | Electricity [%] | | +| | Generator set [%] | | +| | Solar [%] | | +| | Other renewables [%] | | +| | Others (indicate) | | + +### 10.4 Report of site measurement + +**Table 16 – Report of site measurement** + +| Site measurement | | | +|-------------------------|------------------------------------------|--| +| Measurement duration | | | +| | Time duration of the measurement [ $T$ ] | | +| | Measurement start date and time | | +| | Measurement finish date and time | | +| | Repetition time | | +| | Granularity of measurements | | + +**Table 16 – Report of site measurement** + +| Site measurement | | | +|-----------------------------------------------------------------------------|-----------------------------------------------------------------------------------------|--| +| Temperature class and average temperature during the test | | | +| EC in the site | | | +| | Method of measurement
[energy bills/counters, sensors, equipment information, other] | | +| | Measured energy consumption $EC_{MN}$ [Wh or multiples] | | +| | • weekly EC [per week data/graph] | | +| | • monthly EC [if T allows] | | +| | • yearly EC [if T allows] | | +| Traffic offered in the site | | | +| | Method of measurement
[operational counters, backhauling data, MDT, other] | | +| | Measured traffic volume DV [bit or multiples] | | +| | • Weekly traffic [per week data/graph] | | +| | • Monthly traffic [if T allows] | | +| | • Yearly traffic [if T allows] | | +| Coverage of the site [data to be reported per each RAT present in the site] | | | +| | CoA_geo: [km 2 ] | | +| | CoA_des: [km 2 ] | | +| | CoA_Qdes: | | +| | • Failed RRC connection establishments | | +| | • Attempted RRC connection establishments | | +| | • RAB setup failure | | +| | • RAB setup attempted | | +| | • RAB release failure | | +| | • RAB release attempted | | +| Latency of the site [ms -1 /J] | | | +| | Latency | | +| Number of subscribers | | | +| | Number of subscribers | | +| Site energy efficiency | | | +| | Measured energy efficiency $EE_{MN}$ [bit/J] and [m 2 /J] and [ms/J] | | +| | • Weekly energy efficiency [per week data/graph] | | +| | • Monthly energy efficiency [if T allows] | | +| | • Yearly energy efficiency [if T allows] | | + +# 11 Implementation guidelines + +This Recommendation is based on the mobile network area definition under test as described in clause 6, where measurements have to be done according to the metrics as defined in clause 7 and following the procedures as defined in clause 8. In this way, the network under test (composed by any RA network from 2G to 5G) is evaluated in terms of energy efficiency and the results obtained therein are to be filled in the tables reported as an essential part of the specification in clause 10. + +Extrapolation of sub-network results can be used for the assessment of larger networks, in particular when measurements over the total network are not possible due to its dimensions. In this case, the extrapolation approach defined in clause 9 is recommended. + +Careful selection of the sub-networks for measurement is needed to ensure that the results are technically sound and, even if this is not the primary goal, comparable. Of course, results measured in very different environments (different in terms of demography, climatology or topography, but also different due to the goal and function of the network) are hardly comparable and, as said, the purpose of the specification is not to make comparable what is not; the important issue is to introduce a method of testing that can represent a common reference whenever a test of mobile network energy efficiency is performed over an RA network. + +In a case where a network is tested against itself in different time periods, a comparison is sensible only with the attention due to all the parameters listed in the tables of clause 10, especially when referring to temperature and environmental conditions. This highlights the possible reasons for changes in energy efficiency. When considering these parameters, the accuracy of the measurements has to be reported, to ensure the utmost consistency of measurements made in different time periods. + +If, in given regions, there are regulation constraints imposing rules in the deployment of networks, these constraints have to be taken into account when making any comparison. In such cases, only the comparison of networks under the same constraints are possible. + +Regarding the time duration $T$ of the measurement campaigns, the period of the measurements has to be chosen in the most sensible way in terms of particular foreseeable traffic conditions, weather impacts, etc. + +An essential part of this common base method is represented by the tables in clause 10. Even in very different scenarios, these tables need to be filled out completely in order for the measures to be considered as complying with this Recommendation. The test will be considered compliant if, when the measurements are carried out in very different scenarios, the scenarios are described in the tables, considering not only the final energy efficiency results but also how these results have been obtained. + +## Appendix I + +## Implementation examples + +(This appendix does not form an integral part of this Recommendation.) + +### I.1 Implementation examples + +Considering the implementation guidelines reported in clause 11, a set of examples on how to implement this Recommendation is given here. + +A possible application of this Recommendation could be to provide national authorities with a commonly accepted procedure to estimate the efficiency of a radio access technology or a set of RATs deployed by an MNO or a set of MNOs, at a national, regional or city level. This assessment can be performed as a standalone scenario to understand what efficiency is reasonably achievable, or it can be estimated towards a given threshold, to ensure that a minimum level of efficiency is achieved (e.g., after the introduction of new energy savings procedures, or new hardware solutions). + +As another example, this Recommendation could be used to test the efficiency of a network, year-over-year, or in any case against a given time roadmap. The test can be performed over the same sub- or total network, depending on the requirements, and over the network of the same MNO, in a different period of time, i.e., year-over-year or in any case so as to emphasize a time evolution of the EE performances. The full completion of the information in tables in clause 10 is mandatory to check under which conditions the tests have been performed. + +As a final example, this Recommendation could be used without any extrapolation phase (as described in clause 9) when the purpose is to evaluate network functionalities that impact energy efficiency in a small network under test. In such a case, this Recommendation indicates how to proceed to assess the benefits of the mentioned functionalities (when they are activated) with respect to the baseline case (when the functionalities are not active). + +### I.2 Examples of reporting data + +In this clause, an example of the data to be filled in into the tables of clause 10 and clause 9 is given. This example is for explanation purposes only, and the data reported are not to be considered real or binding in any way. + +Table I.1 is Table 14 filled in with example data. + +**Table I.1** + +| Network area under test (partial network #1) | | | +|-----------------------------------------------------------------------|-------------------------------------------------------------|--------------------| +| Demography class
[DU, urban, suburban, rural, sparse] [Table 2] | DU | | +| Topography class [Table 3] | Flat | | +| Climate zone [4] | Temperate | | +| Informative classification [Tables 5 and 6] | DP, PSL | | +| Network area definition
[by demography, by geography, by topology] | Demography | | +| | Number of inhabitants in the network area [estimate] | 150 000 | +| | Network area dimensions
[estimate, km 2 ] | 15 km 2 | + +**Table I.1** + +| Network area under test (partial network #1) | | | +|-----------------------------------------------------|-----------------------------------------------------------------------|-----------------------| +| | Number of sites in the network area
[same RCs?] | 30, of the same RC | +| Type of sites in the network area | | | +| | Number of wide area BS sites | 25 | +| | Number of medium range BS sites | 3 | +| | Number of other sites/equipment
(local area BS, relay nodes, etc.) | 2 | +| Sites categorization | | | +| | Number of sites in an MNO local exchange premise | 5 | +| | Number of sites in buildings not owned by MNO | 20 | +| | Number of sites in a shelter | | +| | Number of any other sites | 5 | +| Multi-MNO sites | | | +| | Number of “single MNO” sites | 20 | +| | Number of co-located multi-MNOs sites | 8 | +| | Number of sites in “network sharing” mode | 2 | +| Multitechnology sites | | | +| | Number of 2G-only sites | 0 | +| | Number of 3G-only sites | 10 | +| | Number of LTE-only sites | 5 | +| | Number of 2G+3G sites | 10 | +| | Other options [indicate] | 5 2G+3G+LTE | +| Backhauling information | | | +| | Predominant type of backhauling
[wireless, fibre, copper...] | Fibre, copper | +| | Number of backhauling links per type | 20 fibres, 10 coppers | +| Energy efficiency in the network area | | | +| | $EE_{MN,DV}$ [b/J] | 180 b/J | +| | $EE_{MN,CoA}$ [m 2 /J] | 3 m 2 /MJ | +| Energy efficiency top-down approach results | | | +| | 100 bit/J | | + +Table I.2 reports an example of a site in the partial network #1 described in Table I.1. + +**Table I.2** + +| Site(s) under test in the network area
(one table per site type to be measured in the network area) | | | +|----------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------| +| Measurement duration | | | +| | Time duration of the measurement [T] | 2 weeks | +| | Measurement start date and time | 2014/07/07 | +| | Measurement finish date and time | 2014/07/20 | +| | Repetition time | Daily | +| | Granularity of measurements | 1 min | +| Type of site | | | +| | Site "layer"
[wide area, medium range, other]
In case of wide area, indicate number of sectors and carriers per sector | Wide area,
3 sectors
2 carriers each sector | +| | Site "technology"
[2G, 3G, 2G+3G, LTE only, 2G+3G+LTE, other] | 3G | +| | Site "MNOs"
[single MNO, co-location, network sharing, other] | Single MNO | +| Site and equipment age | | | +| Initial commission date of the site | | 2005/11/05 initial | +| Commission date of the current equipment in the site | | 2013/07/22 current equipment | +| Temperature | Internal °C | External °C | +| Average temperature [over period T] | 24.2 °C | 28.3 °C | +| Minimum temperature | 18.8 °C | 19.6 °C | +| Maximum temperature | 30.6 °C | 36.4 °C | +| Site infrastructure | | | +| | Site location
[local exchange premise, building, shelter, other] | Outdoor cabinet | +| | Site composition | | +| | • Air conditioners | Yes, 2 kW average power | +| | • Rectifiers/ batteries | Yes, both; 250 W average power | +| | • Fixed network equipment consumption | | +| | Other | | +| | Estimated percentage of infrastructure consumption in the site (ECsi) | 50% | + +**Table I.2** + +| Site(s) under test in the network area
(one table per site type to be measured in the network area) | | +|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------| +| EC of ICT equipment in the site [Wh] | 1.5k | +| EC of all the support equipment in the site [Wh] | 2k | +| Energy efficiency in the site equipment (Energy_ICTequipment / Energy_Total_network) | $1.5/3.5 = 0.43$ | +|
  • – Total electrical energy supplied from the grid
  • – Peak power delivered from the grid
  • – Total site energy storage capacity
  • – Peak shaving features available at the site
| To be determined | +| Energy efficiency enhancement methods affecting the site equipment during the test | Traffic related power from the second carrier | +| Estimated percentage of presence of this site type in the network area | 33% | +| Electricity sources used in the site | | +| | Mains/power grid [%] | +| | Generator set [%] | +| | Solar [%] | +| | Other renewables [%] | +| | Others (indicate) | + +Table I.3 reports the measurement at the site described in Table I.2. + +**Table I.3** + +| Site measurement | | +|-----------------------------------------------------------|------------| +| Measurement duration | | +| Time duration of the measurement [T] | 2 weeks | +| Measurement start date and time | 2014/07/07 | +| Measurement finish date and time | 2014/07/20 | +| Repetition time | Daily | +| Granularity of measurements | 1 min | +| Temperature class and average temperature during the test | | +| Class C, average internal temperature 24.2 °C | | +| EC in the site | | + +**Table I.3** + +| Site measurement | | | +|-----------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------| +| | Method of measurement
[energy bills/counters, sensors, equipment information, other] | Sensors | +| | Measured energy consumption $EC_{MN}$ [Wh or multiples] | | +| |
  • • Weekly EC [per week data/graph]
| Introduce a graph of the kWh in the site, or a table of values, per each week, according to the time granularity of the available data | +| |
  • • Monthly EC [if T allows]
| NA | +| |
  • • Yearly EC [if T allows]
| NA | +| Traffic offered at the site | | | +| | Method of measurement
[operational counters, backhauling data, MDT, other] | Operational counters | +| | Measured traffic volume $DV$ [bit or multiples] | | +| |
  • • Weekly traffic [per week data/graph]
| Introduce a graph of the Gb in the site, or a table of values, per week, according to the time granularity of the available data | +| |
  • • Monthly traffic [if T allows]
| NA | +| |
  • • Yearly traffic [if T allows]
| NA | +| Coverage of the site [data to be reported per each RAT present in the site] | | | +| | $CoA\_geo$ : [km 2 ] | 0.5 | +| | $CoA\_des$ : [km 2 ] | 0.42 | +| | $CoA\_qdes$ : | 84% | +| |
  • • Failed RRC connection establishments
  • • Attempted RRC connection establishments
  • • RAB setup failure
  • • RAB setup attempted
  • • RAB release failure
  • • RAB release attempted
| 658
13 118
322
4998
294
4998 | +| Mobile network energy efficiency | | | +| | Measured energy efficiency [bit/J] | | +| |
  • • Weekly energy efficiency [per week data/graph]
| Introduce a graph of the bit/J in the site, or a table of values, per week, according to the time granularity of the available data | +| |
  • • Monthly energy efficiency [if T allows]
| NA | +| |
  • • Yearly energy efficiency [if T allows]
| NA | + +Table I.4 reports an example of computation results of a total mobile network energy efficiency assessment. The EE values are in the format of tables for partial network #1, and other values are considered in other partial networks in the same partial network area (not reported in this example) to come to the average values in the EE columns. The total EE is evaluated in the measurement period T time-frame (2 weeks) for the DV case, while EC is extrapolated to 1 year as required for CoA EE metric. + +**Table I.4** + +| Demography classification | Percentage of presence (PofP) in the total network area of the class | EEMN in the class | | +|---------------------------|----------------------------------------------------------------------|-------------------------------------|-------------------------------------| +| | | EEMN,DV | EEMN,CoA | +| Dense urban (DU) | 42% | 200 b/J | 2.7 m2/MJ | +| Urban (U) | 20% | 40 b/J | 19 m2/MJ | +| Suburban (SU) | 15% | 8 b/J | 38 m2/MJ | +| Rural (RU) | 13% | 2 b/J | 115 m2/MJ | +| Unpopulated | 10% | NA | NA | +| Overall/total EE | | 103.8 b/J | 28.4 m2/MJ | + +In order to better clarify the example in Table I.4 the following equations explain how to compute the total EE in the cases mentioned above. + +$$EE_{total,DV} = \frac{PofP_{DU} * EE_{DU,av} + PofP_U * EE_{U,av} + PofP_{SU} * EE_{SU,av} + PofP_{Unp} * EE_{Unp,av}}{PofP_{DU} + PofP_U + PofP_{SU} + PofP_{Unp}} = \frac{42 * 200 + 20 * 40 + 15 * 8 + 13 * 2}{42 + 20 + 15 + 13} = 103.8 \text{ b/J} \quad (I.1)$$ + +$$EE_{total,CoA} = \frac{PofP_{DU} * EE_{DU,av} + PofP_U * EE_{U,av} + PofP_{SU} * EE_{SU,av} + PofP_{Unp} * EE_{Unp,av}}{PofP_{DU} + PofP_U + PofP_{SU} + PofP_{Unp}} = \frac{42 * 2.7 + 20 * 19 + 15 * 38 + 13 * 115}{42 + 20 + 15 + 13} = 28.4 \text{ m}^2/\text{MJ} \quad (I.2)$$ + +Note that in the CoA case the extrapolation has been made from $T = 14$ days to 1 year dividing by 26 the results during period $T$ ( $365/14 \sim 26$ ). + +## Bibliography + +- [b-ETSI EN 303 471] ETSI EN 303 471 V1.0.0 (2018), *Environmental Engineering (EE); Energy Efficiency measurement methodology and metrics for Network Function Virtualisation (NFV)*. +- [b-ETSI ES 202 706-1] ETSI ES 202 706-1 (2016), *Environmental Engineering (EE); Metrics and measurement method for energy efficiency of wireless access network equipment Part 1: Power Consumption – Static Measurement Method*. +- [b-ETSI GS NFV 003] ETSI GS NFV 003 V1.2.1 (2014), *Network Functions Virtualisation (NFV); Terminology for Main Concepts in NFV*. +- [b-ETSI TR 103 117] ETSI TR 103 117 V1.1.1 (2012), *Environmental Engineering (EE); Principles for Mobile Network level energy efficiency*. +- [b-ETSI TS 102 706-2] ETSI TS 102 706-2 (2018), *Environmental Engineering (EE); Metrics and Measurement Method for Energy Efficiency of Wireless Access Network Equipment; Part 2: Energy Efficiency – dynamic measurement method*. +- [b-ETSI TS 122 261] ETSI TS 122 261 V15.5.0 (2018), *5G; Service requirements for next generation new services and markets*. +- [b-Eurostat] Eurostat, *Population & Demography – Overview*. +<> +- [b-FAO-1] *Harmonized World Soil Database v 1.2*. +<> +- [b-FAO-2] *Data sources for FAO worldmaps of Koeppen climatologies and climatic net primary production*, 2006. +<[http://www.fao.org/nr/climpag/globgrids/KC\\_commondata\\_en.aspt](http://www.fao.org/nr/climpag/globgrids/KC_commondata_en.aspt)> +- [b-UN] United Nations, *Demographic and Social Statistics*. +<> +- [b-US CB] United States Census Bureau, *Tables*. +<> + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1333-202209-I_PDF-E/14a22f23ced8ba1d63ece69861dbaacc_img.jpg b/marked/L/T-REC-L.1333-202209-I_PDF-E/14a22f23ced8ba1d63ece69861dbaacc_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..1d8deae6031c18707104a329a7eae044811bbb4b --- /dev/null +++ b/marked/L/T-REC-L.1333-202209-I_PDF-E/14a22f23ced8ba1d63ece69861dbaacc_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:f418e2fcf77b057e807e60d0a0a741dd98ab9ee337764072def10cd9ce79d647 +size 5986 diff --git a/marked/L/T-REC-L.1333-202209-I_PDF-E/7f17c430b9598e4d748a8041457810b3_img.jpg b/marked/L/T-REC-L.1333-202209-I_PDF-E/7f17c430b9598e4d748a8041457810b3_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..5e82227b9cad4f3a8ce08633446997e5046fb501 --- /dev/null +++ b/marked/L/T-REC-L.1333-202209-I_PDF-E/7f17c430b9598e4d748a8041457810b3_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:bb3bd91bb5b5f1e01b21f8a8f907a74a7f24aa4541eb1d14ec59c92b892c25da +size 45187 diff --git a/marked/L/T-REC-L.1333-202209-I_PDF-E/cfef993dcc8fb513de79eb1f93cf26ae_img.jpg b/marked/L/T-REC-L.1333-202209-I_PDF-E/cfef993dcc8fb513de79eb1f93cf26ae_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..a356953e7140fa5cd6a4619c4ebaf039c5ca9672 --- /dev/null +++ b/marked/L/T-REC-L.1333-202209-I_PDF-E/cfef993dcc8fb513de79eb1f93cf26ae_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:637faadd68d3b3cffa70e9570d6d0374c487cf558ecb55d5ba3116df6e31ddf5 +size 33994 diff --git a/marked/L/T-REC-L.1341-202512-I_PDF-E/84a1d09fb489061482111515543b60dc_img.jpg b/marked/L/T-REC-L.1341-202512-I_PDF-E/84a1d09fb489061482111515543b60dc_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..ac295b1b0c7f14b1c5a33ef6682b1b017c812477 --- /dev/null +++ b/marked/L/T-REC-L.1341-202512-I_PDF-E/84a1d09fb489061482111515543b60dc_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:37aed4fc114a39843438175326e0b7e1d09a9d6075723d82fea32040fd560ee4 +size 7192 diff --git a/marked/L/T-REC-L.1341-202512-I_PDF-E/raw.md b/marked/L/T-REC-L.1341-202512-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..7169f2c6cd6ec27d07065150bbb072906d54e0a6 --- /dev/null +++ b/marked/L/T-REC-L.1341-202512-I_PDF-E/raw.md @@ -0,0 +1,420 @@ + + +# Recommendation + +## **ITU-T L.1341 (12/2025)** + +SERIES L: Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant + +Energy efficiency, smart energy and green data centres + +--- + +## **Functional requirements for energy efficiency in intelligent Internet of things platforms** + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue circular emblem with a stylized globe and the letters 'ITU' in white. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +### **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|----------------------------------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| Infrastructure including node elements (except cables) | L.200-L.249 | +| General aspects and network design | L.250-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| Optical fibre cable maintenance | L.300-L.329 | +| Infrastructure maintenance | L.330-L.349 | +| Operation support and infrastructure management | L.350-L.379 | +| Disaster management | L.380-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | +| ENVIRONMENTAL SUSTAINABILITY OF ARTIFICIAL INTELLIGENCE AND EMERGING ICT SYSTEMS | L.1800-L.1899 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1341 + +## Functional requirements for energy efficiency in intelligent Internet of things platforms + +## Summary + +With the rapid growth of IoT platform technology, many sensors and devices can be connected. IoT applications require energy efficiency because most IoT devices run on constrained battery power. IoT applications involve many smart devices, making energy issues more essential for decreasing carbon footprints and costs. Moreover, energy efficiency is crucial because IoT platforms comprise many interconnected devices and services that require a lot of energy. With the strong emergence of AI nowadays, the IoT platform is integrated with AI to enhance the decision-making process in the IoT platform, improving the value of the data generated by the IoT platform. The integration between the IoT platform and AI functionality gave rise to a new paradigm called the intelligent IoT platform. + +Recommendation ITU-T L.1341 specifies the functional requirements essential for achieving sustainable and robust energy efficiency in intelligent Internet of Things (IoT) platforms. These platforms, defined as comprehensive technological frameworks integrating artificial intelligence (AI) and edge computing, face significant energy challenges due to the computational complexity introduced by AI and the collective power demand of a massive volume of interconnected devices. Recognizing that the integration of artificial intelligence (AI) and the immense scale of IoT deployments introduce significant energy consumption challenges, this document mandates a holistic approach to energy management across the entire system. This Recommendation first identifies considerations for energy management in intelligent IoT platforms in respect of hardware specifications, data collection and processing, AI models and operation and management. Functional requirements for energy efficiency in intelligent IoT platforms are then addressed in regard to intelligent data acquisition and processing, energy-efficient communication protocols, dynamic AI resource management, energy monitoring and management, AI-enhanced energy optimization and lifecycle energy efficiency management. In addition, best practices to improve energy efficiency in intelligent IoT platforms are given in Appendix I, with energy-aware IoT architecture design, energy-efficient data management, green networks and communication, AI-based energy optimization, energy harvesting and sustainable power solutions and cooperative energy saving techniques with the edge and cloud. + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.1341 | 2025-12-14 | 5 | 11.1002/1000/16650 | + +## Keywords + +Artificial intelligence, energy efficiency, functional requirement, intelligent Internet of Things platforms, Internet of things. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, and information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2026 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|---------------------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 1 | +| 4 Abbreviations and acronyms ..... | 1 | +| 5 Conventions ..... | 2 | +| 6 Considerations for energy efficiency in intelligent IoT platforms ..... | 2 | +| 6.1 Overview ..... | 2 | +| 6.2 Hardware specifications aspects..... | 3 | +| 6.3 Data collection and processing aspects ..... | 3 | +| 6.4 AI models aspects..... | 3 | +| 6.5 Operation and management aspects ..... | 4 | +| 7 Functional requirements for energy efficiency in intelligent IoT platforms ..... | 4 | +| 7.1 Intelligent data acquisition and processing..... | 4 | +| 7.2 Energy-efficient communication protocols ..... | 5 | +| 7.3 Dynamic AI resource management ..... | 6 | +| 7.4 Energy monitoring and management..... | 7 | +| 7.5 AI-enhanced energy optimization ..... | 8 | +| 7.6 Lifecycle energy efficiency management..... | 9 | +| Appendix I – Best practices to improve energy efficiency in intelligent IoT platforms ..... | 11 | +| I.1 Energy-aware IoT architecture design..... | 11 | +| I.2 Energy-efficient data management..... | 11 | +| I.3 Green network and communication..... | 11 | +| I.4 AI-based energy optimization ..... | 12 | +| I.5 Energy harvesting and sustainable power solutions ..... | 12 | +| I.6 Cooperative energy saving techniques with edge and cloud..... | 13 | +| Bibliography..... | 14 | + + + +# Recommendation ITU-T L.1341 + +## Functional requirements for energy efficiency in intelligent Internet of things platforms + +# 1 Scope + +This Recommendation presents challenges related to energy efficiency in intelligent IoT platforms and provides functional requirements to improve it. + +This includes: + +- energy efficiency issues that occur in intelligent IoT platforms; +- functional requirements to improve energy efficiency in intelligent IoT platforms. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +None. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following term defined elsewhere: + +**3.1.1 Internet of Things [b-ITU-T Y.4000]:** A global infrastructure for the information society, enabling advanced services by interconnecting (physical and virtual) things based on existing and evolving interoperable information and communication technologies. + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following term: + +**3.2.1 intelligent Internet of things platform:** A comprehensive technological framework that serves as a global infrastructure for the information society, enabling advanced services by interconnecting physical and virtual things and integrating artificial intelligence and machine learning algorithms to enable autonomous decision-making, predictive maintenance and system optimization. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|----------------------------------| +| AI | Artificial Intelligence | +| ARQ | Automatic Repeat request | +| BLE | Bluetooth Low Energy | +| CoAP | Constrained Application Protocol | +| DNN | Deep Neural Network | + +| | | +|--------|----------------------------------------| +| DVFS | Dynamic Voltage and Frequency Scaling | +| FEC | Forward Error Correction | +| FPGA | Field Programmable Gate Array | +| GHG | Greenhouse Gas | +| GPU | Graphics Processing Unit | +| HVAC | Heating, Ventilation, Air Conditioning | +| IoT | Internet of Things | +| LPWAN | Low Power Wide Area Network | +| MAC | Media Access Control | +| MQTT | Message Queuing Telemetry Transport | +| NB-IoT | Narrowband Internet of Things | +| NPU | Neural Processing Unit | +| TinyML | Tiny Machine Learning | + +# 5 Conventions + +None. + +# 6 Considerations for energy efficiency in intelligent IoT platforms + +## 6.1 Overview + +An intelligent Internet of Things (IoT) platform constitutes a comprehensive technological framework that enables the seamless interconnection, management and analytics of diverse IoT devices while incorporating advanced intelligence capabilities. It provides a scalable architecture for device registration, authentication and secure communication protocols that ensure data integrity across heterogeneous networks. The platform integrates artificial intelligence (AI) and machine learning algorithms to process and analyse the collected data, enabling autonomous decision-making, predictive maintenance and system optimization without continuous human intervention. Additionally, it implements standardized interfaces and protocols to ensure interoperability between devices from different manufacturers and across various industrial sectors. The intelligent IoT platform incorporates edge computing capabilities to process time-sensitive data locally, reducing latency and bandwidth consumption while maintaining cloud connectivity for extensive data processing and storage. Furthermore, it provides comprehensive device management tools, including remote configuration, firmware updates and health monitoring to ensure operational efficiency throughout a device's lifecycle. + +Energy efficiency challenges in intelligent IoT platforms pertains to the substantial energy consumption resulting from the usage of AI in a system, which significantly increases the system's computational complexity, leading to higher energy consumption. Additionally, the collective operation of numerous sensors and devices in the platform also affects the system's energy consumption. While individual devices may have low power requirements, the sheer volume of these devices in intelligent IoT set-ups leads to substantial energy demands. This challenge is exacerbated by continuous sensing, energy-inefficient communication protocols and energy-intensive data processing on cloud-based servers. The cumulative energy consumption over extended operational periods poses environmental and economic concerns. This clause presents some of the common energy efficiency considerations identified in intelligent IoT platforms. + +## 6.2 Hardware specifications aspects + +Hardware is a critical factor that directly impacts the energy efficiency of an IoT platform. Inadequate hardware provisioning can lead to significant energy waste. Over-provisioned hardware configurations may result in unnecessary idle power consumption and increase auxiliary energy usage, such as for cooling, even under low computational loads. Conversely, under-specified hardware may operate under continuous high load, leading to overheating, reduced component lifespan and severe energy inefficiencies. To ensure optimal energy efficiency, hardware specification should be determined based on the actual AI processing workload and operational duty cycles of the platform. Additionally, energy-aware hardware components that support power management features such as power gating and dynamic voltage and frequency scaling (DVFS) should be utilized to enable energy control at the system level. The absence of proper system-level implementation of low-power features, such as sleep mode, can lead to unnecessary energy consumption during idle periods. + +Artificial intelligence (AI) algorithms, particularly those involving deep learning or large-scale inference models, typically require significantly higher computational resources compared to conventional algorithms. Consequently, they demand more energy-intensive hardware such as high-performance microcontrollers, CPUs, GPUs and dedicated AI accelerators. In intelligent IoT platforms, where AI functionalities are deployed across multiple layers, including sensor nodes, edge nodes and cloud systems, diverse hardware components are integrated to support distributed AI processing. Selecting appropriate hardware specifications for each layer is essential, as it directly impacts the system's overall energy consumption, thermal profile and cost-effectiveness. Therefore, intelligent IoT platforms should adopt a hardware configuration strategy that balances AI performance requirements with energy efficiency and lifecycle costs. This includes considering energy-aware hardware, workload-specific AI acceleration and dynamic power scaling mechanisms. + +## 6.3 Data collection and processing aspects + +In intelligent IoT platforms, the continuous data collection from a large number of sensors may result in significant cumulative energy consumption, despite the low-power characteristics of individual devices. Real-time data transmission from sensors can cause network congestion and redundant traffic, leading to inefficient use of communication resources and increased power consumption. In environments with poor signal quality, frequent retransmissions may occur, which is considered a major source of energy inefficiency in the communication layer. Centralized cloud-based data processing may incur high energy costs due to massive data transmission and storage requirements, and may also introduce latency issues in time-sensitive applications. + +These inefficiencies can be mitigated through edge computing techniques such as data pre-filtering, event-driven sensing, data compression and in-network data aggregation. The selection and application of appropriate low-power communication protocols, such as LPWAN, NB-IoT and Zigbee, should be considered essential for energy-efficient data transmission. Furthermore, dynamic traffic control and context-aware communication strategies should be implemented in parallel to further reduce energy consumption. + +In addition, the energy costs of data are not limited to collection and transmission. The long-term energy consumption of data storage and its eventual disposal should also be addressed within the platform's data lifecycle management. Effective data management strategies can significantly reduce the overall energy footprint of intelligent IoT systems by eliminating the long-term storage and processing of unnecessary data. This comprehensive approach ensures energy is conserved throughout the entire data lifecycle, from initial collection to final disposal. + +## 6.4 AI models aspects + +In intelligent IoT platforms, the simultaneous operation of multiple AI models for diverse functionalities can lead to a substantial increase in computational overhead and energy consumption. When individual AI models are designed per sensor or data type, the number of deployed models + +may increase exponentially, leading to system inefficiencies. Moreover, deploying overly complex or large-scale models for simple tasks results in unnecessary power consumption and elevated hardware resource requirements. + +The frequency of AI model retraining also affects energy efficiency. Excessively frequent retraining consumes additional power without proportional performance gains, whereas infrequent retraining may result in outdated models that degrade operational accuracy and efficiency. Furthermore, the placement of AI models, across cloud, edge or sensor tiers, significantly influences the energy cost of data transmission and processing. + +To address these inefficiencies, intelligent IoT platforms should implement lightweight AI models, performance-triggered retraining schedules and deployment strategies that align with the computational capabilities and energy profiles of each system tier. Therefore, optimization of model quantity, complexity, operation frequency and deployment location is essential for minimizing overall energy consumption. + +In addition, AI model design should also consider energy consumption prediction models as part of the optimization process. Adopting model compression techniques such as quantization, pruning and knowledge distillation should also be considered to reduce the size and computational requirements of models, thereby lowering energy consumption. + +## **6.5 Operation and management aspects** + +Even if individual components within an intelligent IoT platform are designed with energy efficiency in mind, platform-wide operational inefficiencies can lead to significant energy waste at the system level. Inefficiencies may arise when processing responsibilities across system layers, such as sensors, edge nodes and cloud systems, are not clearly defined or balanced. The unnecessary activation of application services, redundant AI inference operations or superfluous intermediate processing stages can also result in increased energy consumption. Furthermore, a lack of modularity, scalability or flexibility in the platform architecture can lead to repeated reconfiguration when introducing new features, limiting opportunities for system-wide energy optimization. + +To mitigate such inefficiencies, intelligent IoT platforms should implement standardized interface specifications for inter-functional cooperation, eliminate redundant functions and apply architectural optimization strategies. In addition, continuous monitoring of system-wide energy consumption and the implementation of feedback-based resource allocation mechanisms are essential to sustaining long-term energy efficiency improvements. Inefficient energy management denotes the inadequate planning and control of energy resources, leading to wasteful consumption and higher costs. This inefficiency arises when systems fail to implement energy-saving measures, such as utilizing low-power modes during idle periods. It leads to an unnecessary strain on resources and contributes to environmental degradation through heightened carbon emissions. + +# **7 Functional requirements for energy efficiency in intelligent IoT platforms** + +## **7.1 Intelligent data acquisition and processing** + +Intelligent IoT platforms shall implement energy-aware data acquisition and processing to minimize unnecessary energy consumption. Event-driven sensing and adaptive sampling techniques shall be applied to acquire meaningful data with minimal energy consumption. Sampling frequency and resolution should be dynamically adjusted based on environmental context and application-specific requirements. Raw data shall be preprocessed at the edge nodes in real time to reduce unnecessary data transmission and storage overhead. Key processing functions such as data filtering, compression (e.g., delta or lossless) and anomaly detection should contribute to reduced energy consumption during transmission and storage. + +Data flow control should be based on priority and relevance, ensuring that only critical information is forwarded to upper layers (e.g., cloud or central nodes). Data that cannot be processed locally at the edge should be offloaded to cloud or data centre infrastructures based on energy and latency constraints. The platform should maintain acceptable levels of quality of data while minimizing energy consumption through intelligent data management strategies. AI-based decision models should determine which data to collect or discard, based on predicted relevance, anomaly scores or contextual information. The entire data pipeline should be optimized based on energy profiling of devices, network conditions and processing capabilities. + +Additionally, the platform shall implement mechanisms for dynamic resource allocation and load balancing within the data processing pipeline to optimize energy usage based on real-time computational demands. + +**Table 1 – Functional requirements for intelligent data acquisition and processing** + +| Category | Description | Purpose | +|--------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------| +| Energy-aware data acquisition | The platform shall employ event-driven sensing and adaptive sampling to acquire only meaningful data. | To reduce energy consumption by activating sensors only when necessary. | +| Edge preprocessing | Raw data shall be preprocessed in real time at the edge to reduce unnecessary data transmission and storage overhead. | To conserve energy by avoiding the transmission and processing of large volumes of raw data. | +| Data compression and filtering | Key processing functions like data filtering, compression and anomaly detection should be applied to reduce energy consumption during data transmission and storage. | To lower energy consumption by reducing the volume of data transmitted and stored. | +| Intelligent data flow control | Data flow control should be based on priority and relevance, ensuring only critical information is forwarded to higher layers. | To focus resources on essential information, enhancing overall system energy efficiency. | +| AI-based data decision-making | AI models should be used to determine which data to collect or discard based on predicted relevance and importance. | To prevent unnecessary data collection and transmission, directly reducing energy waste. | +| Data pipeline optimization | The entire data pipeline should be optimized based on the energy profile of devices, network conditions and processing capabilities. | To ensure the platform automatically selects the most energy-efficient data path based on dynamic system conditions. | +| Dynamic resource allocation | The platform shall implement mechanisms for dynamic resource allocation and load balancing to optimize energy usage based on real-time computational demands. | To prevent excessive energy consumption by efficiently managing and distributing computing resources, thereby optimizing overall system performance. | + +## 7.2 Energy-efficient communication protocols + +Communication protocol design for energy-efficient IoT platforms shall consider low-power operation across all network layers. Wireless communication shall rely on low-power technologies (e.g., LPWAN, BLE, Zigbee), with protocol selection tailored to specific application requirements such as latency, range and throughput. Energy-aware error recovery mechanisms shall be implemented to minimize packet loss and retransmissions during communication, using techniques such as lightweight automatic repeat request (ARQ) or forward error correction (FEC). Support for sleep and wake-up mechanisms shall be available at both media access control (MAC) and network layers, utilizing low-duty-cycle MAC protocols. Publish-subscribe communication models (e.g., + +message queuing telemetry transport (MQTT), constrained application protocol (CoAP) observe) are preferred over traditional message-based models for reducing energy consumption through lightweight signalling and efficient data routing. Protocol behaviour shall adapt dynamically to device battery status, link quality and network congestion levels to maintain energy efficiency. Energy-aware routing algorithms shall incorporate residual energy metrics of nodes to select optimal communication paths and extend network lifetime. Hierarchical topologies can reduce transmission distances via intermediate nodes. In addition, the platform shall select and implement lightweight security protocols to minimize the energy overhead associated with encryption and authentication without compromising data integrity. + +**Table 2 – Functional requirements for energy-efficient communication protocols** + +| Category | Description | Purpose | +|------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------| +| Low-power protocol selection | The platform shall rely on low-power wireless communication technologies (e.g., LPWAN, BLE, Zigbee) that are selected based on specific application needs. | To minimize energy consumption at the physical and link layers by using protocols designed for low-power operation. | +| Energy-aware error recovery | The platform shall implement mechanisms (e.g., lightweight ARQ, FEC) to minimize packet loss and subsequent retransmissions. | To prevent energy waste caused by retransmitting data over the network due to packet errors. | +| Sleep and wake-up mechanisms | The platform shall support low-duty-cycle sleep and wake-up functionalities at the MAC and network layers. | To conserve energy by placing devices in low-power modes during idle periods. | +| Publish-subscribe models | The platform should prefer publish-subscribe communication models (e.g., MQTT, CoAP) over traditional request-response models for data routing. | To reduce signalling overhead and improve routing efficiency, thereby lowering energy consumption. | +| Dynamic protocol adaptation | Protocol behaviour shall dynamically adapt to factors like battery status, link quality and network congestion to maintain energy efficiency. | To ensure the communication protocol remains optimized for energy efficiency under changing operational conditions. | +| Energy-aware routing | The platform shall use routing algorithms that incorporate a node's residual energy to select the most energy-efficient communication paths. | To extend the overall network lifetime and prevent the premature failure of individual nodes due to energy depletion. | +| Lightweight security | The platform shall select and implement lightweight security protocols to minimize the energy overhead of encryption and authentication. | To balance security needs with energy efficiency, preventing security measures from consuming excessive energy. | + +## 7.3 Dynamic AI resource management + +Due to the high energy consumption of AI processing, efficient resource management is essential in intelligent IoT platforms to maintain energy sustainability. The platform shall support dynamic AI workload placement across cloud, edge and device levels, based on latency, energy constraints and computational availability. Lightweight AI models (e.g., TinyML, quantized deep neural networks (DNNs)) shall be executable on edge devices, while complex analytical tasks should be offloaded to the cloud infrastructure. AI accelerators (e.g., graphics processing unit (GPU), neural processing unit (NPU), field programmable gate array (FPGA)) should implement dynamic voltage and frequency scaling (DVFS) to optimize energy consumption under varying workloads. Resource allocation shall be governed by scheduling policies that consider task priority, latency constraints and predefined + +energy budgets. Distributed AI tasks such as collaborative inference or federated learning shall enable energy load balancing through inter-node cooperation. Computational resources should support power gating or low-power idle modes based on utilization and real-time energy profiles. Real-time inference tasks should be prioritized using fast-path scheduling, while non-time-critical tasks can be deferred using delayed execution policies. These requirements shall ensure sustainable and efficient AI operation in energy-constrained IoT environments. + +**Table 3 – Functional requirements for dynamic AI resource management** + +| Category | Description | Purpose | +|-------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Dynamic workload placement | The platform shall support the dynamic placement of AI tasks across cloud, edge and device levels. | To optimize energy usage by executing tasks on the most suitable and energy-efficient computational resource. | +| AI model efficiency | Lightweight AI models (e.g., TinyML, quantized DNNs) shall be executable on edge devices to reduce the need for high-energy data transmission. | To minimize computational and energy overhead by matching model complexity to the capabilities of the device. | +| Hardware power management | AI accelerators should implement features like Dynamic Voltage and Frequency Scaling (DVFS) and power gating. | To dynamically adjust the power consumption of computational resources based on varying workloads and utilization, preventing energy waste during idle or low-load periods. | +| Resource scheduling policies | Resource allocation shall be governed by scheduling policies that consider task priority, latency constraints and energy budgets. | To ensure that critical tasks are executed efficiently while non-critical tasks can be deferred to save energy. | +| Distributed AI load balancing | The platform shall enable energy load balancing for distributed AI tasks (e.g., federated learning) through inter-node cooperation. | To distribute the energy burden of AI processing across multiple devices, avoiding premature battery depletion in any single node. | + +## 7.4 Energy monitoring and management + +The platform shall include energy consumption monitoring capabilities for each component, including sensors, gateways, edge nodes and cloud modules. Real-time energy consumption data shall be collected at the device and subsystem levels to enable energy usage pattern analysis using temporal and contextual correlations. The platform shall support predefined energy budgets and enforce budget adherence through adaptive resource control mechanisms. Key energy performance indicators shall be continuously monitored and used to optimize platform operations. The platform should include anomaly detection mechanisms to identify abnormal energy consumption early and trigger automated mitigation actions. Energy consumption data shall be visualized using dashboards and analytics tools that provide intuitive insights for system administrators. Predictive energy models shall estimate future consumption based on device status, workload characteristics and environmental conditions, leveraging machine learning where appropriate. The platform shall implement a closed-loop energy optimization framework that automatically adjusts device or service states based on predefined energy policies. Energy monitoring shall be applied consistently across edge, cloud and user terminal components, and support shall be centralized or through federated management. These capabilities form the foundation for real-time energy optimization in intelligent IoT platforms. + +**Table 4 – Functional requirements for energy monitoring and management** + +| Category | Description | Purpose | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------| +| Component-level monitoring | The platform shall include energy monitoring capabilities for each component, including sensors, gateways, edge nodes and cloud modules. | To identify which parts of the system are consuming the most energy and pinpoint sources of inefficiency. | +| Real-time data collection | The platform shall collect real-time energy consumption data at the device and subsystem levels. | To enable precise analysis of energy usage patterns and support real-time optimization. | +| Budget enforcement | The platform shall support predefined energy budgets and enforce adherence using adaptive resource control mechanisms. | To ensure the system operates within specific energy limits and prevents uncontrolled consumption. | +| Anomaly detection | The platform should include anomaly detection mechanisms to identify and trigger automated mitigation for abnormal energy consumption. | To quickly detect and respond to unusual power usage, which may indicate a system fault or inefficiency. | +| Predictive modelling | The platform shall use predictive energy models to estimate future consumption based on device status, workload and environmental conditions. | To enable proactive energy management and optimization by anticipating potential inefficiencies. | +| Closed-loop optimization | The platform shall implement a closed-loop framework that automatically adjusts system states based on predefined energy policies. | To ensure continuous, automated energy efficiency without constant human intervention. | + +## 7.5 AI-enhanced energy optimization + +AI shall be utilized as an advanced tool for energy optimization in intelligent IoT platforms. The platform shall support AI models for energy consumption prediction, anomaly detection and optimal control of devices and subsystems. AI models shall be able to learn temporal patterns, environmental conditions and user behaviours to derive energy-saving strategies. Reinforcement learning-based energy controls should support dynamic policy adaptation in continuously changing operational contexts. Predictive controls using AI should be applied to HVAC, lighting and motor systems to maximize energy savings. AI-based workload distribution and resource allocation should be applicable in collaborative architectures involving cloud servers, edge nodes and end devices. AI models should autonomously switch device operation modes based on power status, workload conditions and user preferences. The platform should apply learned energy optimization policies in real time and update them based on changing conditions. + +**Table 5 – Functional requirements for AI-enhanced energy optimization** + +| Category | Description | Purpose | +|-------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------| +| AI-based control models | The platform shall use AI models for predicting energy consumption, detecting anomalies and optimally controlling devices and subsystems. | To leverage advanced analytical capabilities for informed, proactive energy management. | +| Adaptive learning | AI models shall be able to learn and adapt energy-saving strategies based on changing temporal patterns, environmental conditions and user behaviours. | To ensure the platform's energy policies remain effective and relevant in dynamic operational contexts. | + +**Table 5 – Functional requirements for AI-enhanced energy optimization** + +| Category | Description | Purpose | +|---------------------------------|------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------| +| Predictive optimization | The platform should apply predictive controls using AI to systems like HVAC, lighting and motors. | To maximize energy savings by anticipating future needs and adjusting system states accordingly. | +| Intelligent resource allocation | AI models should manage workload distribution and resource allocation in collaborative architectures (cloud, edge, devices). | To balance the energy load across the entire system, preventing resource bottlenecks and over-consumption on any single component. | +| Autonomous mode switching | AI models should autonomously switch device operation modes based on power status, workload conditions and user preferences. | To enable real-time, hands-free energy conservation by automatically adjusting devices to the most energy-efficient state. | + +## 7.6 Lifecycle energy efficiency management + +Energy efficiency in IoT platforms shall be managed based on the full lifecycle of devices and systems. Strategies shall be established to minimize energy consumption across all lifecycle phases including design, development, manufacturing, operation and end-of-life management. + +In the design phase, components such as ultra-low-power chips, high-efficiency sensors and recyclable materials shall be prioritized. In the operational phase, dynamic power management, periodic software updates and continuous energy monitoring shall be implemented. Predictive analytics should be used to estimate device lifespan and degradation trends in order to determine appropriate replacement intervals. Modular design should be adopted to enable component recovery and reuse at the end-of-life phase. + +The platform shall be capable of quantifying and reporting total energy consumption and greenhouse gas (GHG) emissions throughout the lifecycle. Lifecycle-based energy management contributes to long-term cost reduction and environmental impact mitigation. + +**Table 6 – Functional requirements for lifecycle energy efficiency management** + +| Category | Description | Purpose | +|-----------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------| +| Full lifecycle management | The platform shall manage energy efficiency across all lifecycle phases, including design, development, manufacturing, operation and end-of-life management. | To ensure a holistic approach to energy conservation that extends beyond the operational lifespan of the devices. | +| Design phase optimization | Ultra-low-power chips, high-efficiency sensors and recyclable materials shall be prioritized during the design and development phase. | To embed energy-saving features into the hardware from the very beginning, setting a foundation for efficiency. | +| Operational phase management | The platform shall implement dynamic power management, periodic software updates and continuous energy monitoring during its operational phase. | To actively manage and optimize energy consumption based on real-time conditions. | +| Predictive analytics for lifespan | Predictive analytics should be used to estimate device lifespan and degradation trends. | To determine the optimal time for component replacement or maintenance, preventing energy inefficiencies from aging hardware. | + +**Table 6 – Functional requirements for lifecycle energy efficiency management** + +| Category | Description | Purpose | +|------------------------|--------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------| +| End-of-life strategies | Modular design should be adopted to facilitate the recovery and reuse of components at the end-of-life phase. | To minimize the environmental impact and energy footprint associated with manufacturing new components. | +| Quantifiable reporting | The platform shall be capable of quantifying and reporting total energy consumption and greenhouse gas emissions throughout the lifecycle. | To provide transparent and measurable data for assessing the long-term environmental and economic impact of the system. | + +## Appendix I + +## Best practices to improve energy efficiency in intelligent IoT platforms + +(This appendix does not form an integral part of this Recommendation.) + +### I.1 Energy-aware IoT architecture design + +Energy-efficient IoT platforms require energy-aware architectural design from the early development stages. This involves considering energy flow and consumption patterns across the entire system, including sensors, gateways, networks and cloud/edge infrastructures. At the hardware level, ultra-low-power microcontrollers and components supporting dynamic sleep or standby modes should be prioritized. On the software side, energy-aware mechanisms include event-driven processing architectures, lightweight protocol stacks and dynamic power gating during idle states. Energy profiling among functional blocks can help suppress redundant computations and reduce the frequency and volume of data transmission and processing. The platform architecture should adopt a hierarchical structure, where edge nodes perform preprocessing to minimize data transmission to the cloud. The platform should be capable of dynamically adapting services based on the energy profiles of heterogeneous IoT devices. Energy cost modelling tools can be utilized during the initial design phase to inform architectural decisions and estimate long-term energy impacts. This approach ensures sustained energy efficiency throughout future platform scalability and maintenance. Ultimately, energy-aware architecture is critical for realizing reliable and scalable IoT services with minimized power consumption. + +### I.2 Energy-efficient data management + +The processes of data acquisition, storage, transmission and processing can significantly contribute to energy consumption. Energy-efficient data management techniques are essential at each stage of the data pipeline. Event-driven sensing can reduce unnecessary collection by triggering data collection only when significant environmental changes or threshold conditions are detected. To minimize transmission frequency, local preprocessing techniques such as filtering, delta encoding and lossless compression should be employed at the device or edge gateway level. Deduplication and intelligent filtering, such as anomaly-based or rule-based schemes, are effective in reducing redundant transmissions and preserving only meaningful information. Tiered storage strategies classify data as hot or cold based on access frequency and allocate them to appropriate storage media (e.g., SSD for hot data, HDD or NVM for cold data) to reduce energy consumption. Data analytics tasks should be executed on demand, using a hybrid approach that combines batch and stream processing depending on latency and energy requirements. Metadata-aware scheduling can allow optimal timing of data processing tasks, thereby distributing computational load and avoiding peak energy consumption periods. Distributed file systems and edge caching strategies can reduce communication overhead and access latency, especially in large-scale or geographically distributed IoT deployments. Data lifecycle management should ensure periodic deletion or archival of obsolete data, which reduces both storage requirements and associated energy consumption. + +### I.3 Green network and communication + +Energy-efficient communication is a critical factor in the overall power consumption of IoT platforms. The application of green network technologies is essential to optimizing energy usage. Low-power wireless communication protocols such as LPWAN (e.g., LoRaWAN, NB-IoT), Zigbee and Bluetooth Low Energy (BLE) should be carefully matched to IoT application requirements to minimize communication energy overhead. Techniques such as duty cycling, adaptive transmission control and sleep scheduling help reduce idle listening and optimize energy consumption in device-to-device and device-to-gateway communication. MAC protocol design should balance energy efficiency with latency tolerance. Predictive MAC protocols and TDMA-based approaches + +are commonly used to reduce collisions and enable synchronized communication schedules. Mesh and cluster-based topologies can reduce transmission distance and redundant data forwarding, contributing to network-wide energy efficiency and robustness. Analysing network traffic patterns enables dynamic rerouting to avoid congestion and reduce energy consumption by selecting optimal data paths. Energy-aware routing algorithms dynamically determine optimal communication paths based on residual battery level, transmission distance and current network load. In 5G and future 6G-based IoT environments, energy-efficient network management can be achieved through network function virtualization and software-defined networking, which enable centralized control and flexible resource provisioning. These communication optimization techniques can contribute to reducing the overall energy consumption of the platform while maintaining required levels of service quality and network reliability. + +### **I.4 AI-based energy optimization** + +Artificial intelligence can play a central role in energy optimization for intelligent IoT platforms, enabling adaptive, data-driven decision-making across various operational levels. AI algorithms can analyse sensor data in real-time to suppress unnecessary device activation, forecast energy consumption patterns and generate optimized control commands based on contextual awareness. Predictive control techniques can apply trained models to major energy loads such as HVAC systems, lighting and motors, reducing energy waste by anticipating future environmental or occupancy conditions. Reinforcement learning can continuously adapt energy control strategies based on IoT device states and dynamic environmental feedback, learning optimal actions through trial-and-error interactions. Federated learning can enable collaborative model training across distributed devices without sharing raw data, thus preserving privacy and reducing communication overhead in energy data analysis. AI-based task prioritization can allow dynamic resource scheduling and intelligent sleep mode management, optimizing device uptime based on operational importance and data criticality. AI-driven anomaly detection models can identify abnormal energy usage patterns at an early stage, enabling prompt diagnosis and fault mitigation. Lightweight AI models, such as quantized neural networks or pruning-based architectures, can reduce computational load on edge devices and enable real-time inference. + +### **I.5 Energy harvesting and sustainable power solutions** + +Energy harvesting technologies can provide a viable alternative power source to ensure the continuous operation of IoT devices, especially in environments where wired power supply or frequent battery replacement is not feasible. Harvestable ambient energy sources include solar, vibrational (piezoelectric), thermal (thermoelectric) and radio frequency energy. These sources can be used either to directly power the device or to charge energy storage components. When combined with ultra-low-power circuitry, energy harvesting alone may be sufficient to support long-term operation of low-duty-cycle IoT devices. Energy storage components such as supercapacitors and high-efficiency lithium-ion batteries are essential for buffering harvested energy and supplying it during periods of insufficient ambient energy. Hybrid power configurations, combining energy harvesting with grid or battery-based power supplies, can enhance both reliability and energy efficiency, especially for mission-critical or intermittently-connected IoT systems. Energy prediction algorithms can estimate future energy availability based on environmental patterns and adjust device duty cycles or operation modes accordingly. The IoT platform should continuously monitor the power status of edge devices and dynamically adjust operational policies (e.g., data transmission frequency, sensing rate) based on the predicted or real-time energy availability. Sustainable power solutions significantly improve the reliability of IoT operations, especially in remote, inaccessible or hazardous environments where manual maintenance is difficult or costly. + +### **I.6      Cooperative energy saving techniques with edge and cloud** + +Cooperation between edge and cloud resources is a key factor in increasing the energy efficiency of intelligent IoT platforms. Edge computing enables local processing and real-time control of data, reducing communication delays and transmission energy. The cloud is ideal for tasks requiring high-performance computation or managing long-term learning models, and the cooperation between the two areas enables the optimal distribution of resources. Task offloading technology allows for tasks to be switched to the cloud and vice versa, depending on the load or power state of the edge device. Context-aware scheduling can dynamically adjust compute resources and energy based on location, time and user patterns. Edge-to-edge collaboration reduces power consumption by distributing computation and data across neighbouring edge devices. A hybrid energy management framework that combines cloud-centric global optimization policies with edge-centric local control strategies is required. Intelligent Internet of Things platforms should have collaborative orchestration capabilities that use AI-based energy forecasting to determine which computation should be performed at which location. In addition, virtualization of cloud resources and workload consolidation techniques can minimize energy consumption in the data centre. This edge-cloud collaborative energy reduction strategy contributes to the scalability and reliability of IoT platforms. + +## Bibliography + +- [b-ITU-T Y.4000] Recommendation ITU-T Y.4000/Y.2060 (2012), *Overview of the Internet of things*. + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|----------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1350-201610-I_PDF-E/367926125450c2bc3f4bdca9d59a62ba_img.jpg b/marked/L/T-REC-L.1350-201610-I_PDF-E/367926125450c2bc3f4bdca9d59a62ba_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..4dee8d6bca6c4220f5efa85e849eb4c2a13d746d --- /dev/null +++ b/marked/L/T-REC-L.1350-201610-I_PDF-E/367926125450c2bc3f4bdca9d59a62ba_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:1bedbfd82442cbe74f8e35ab85dfa004cc4e7391133319ebf4d6736ab9d3bd6b +size 61240 diff --git a/marked/L/T-REC-L.1350-201610-I_PDF-E/5a4e62bead259c258d069fd3663ea670_img.jpg b/marked/L/T-REC-L.1350-201610-I_PDF-E/5a4e62bead259c258d069fd3663ea670_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..9ef64879470596b3776c3602c8afafca8b6e4d5d --- /dev/null +++ b/marked/L/T-REC-L.1350-201610-I_PDF-E/5a4e62bead259c258d069fd3663ea670_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:83efe7f3d6b6b409dd81067ad9009ad04c1e7812af032abaab432719c7dbcb89 +size 61416 diff --git a/marked/L/T-REC-L.1350-201610-I_PDF-E/6ed175c791b5e156d9c98a8dbcc3318c_img.jpg b/marked/L/T-REC-L.1350-201610-I_PDF-E/6ed175c791b5e156d9c98a8dbcc3318c_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..b225e7ec6f52669bd437c0777fb208f4573d8abd --- /dev/null +++ b/marked/L/T-REC-L.1350-201610-I_PDF-E/6ed175c791b5e156d9c98a8dbcc3318c_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:83eabfbf43f7351feddefe55cb47d92d1ea24336a5e09bfa81187d93c47efabf +size 6964 diff --git a/marked/L/T-REC-L.1350-201610-I_PDF-E/a5ee5c23b6dc52ec1d724b76d5a5f58f_img.jpg b/marked/L/T-REC-L.1350-201610-I_PDF-E/a5ee5c23b6dc52ec1d724b76d5a5f58f_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..6dac30b1e32613bbcca0bd92e8870a6b6531d4a3 --- /dev/null +++ b/marked/L/T-REC-L.1350-201610-I_PDF-E/a5ee5c23b6dc52ec1d724b76d5a5f58f_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:5f9052ce5feed7f8ee5e2f484de50f264fef7c5d602e537d31d723f389120d95 +size 52175 diff --git a/marked/L/T-REC-L.1350-201610-I_PDF-E/raw.md b/marked/L/T-REC-L.1350-201610-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..3e267c8f88b247b44686320c0af54b4dd568cd30 --- /dev/null +++ b/marked/L/T-REC-L.1350-201610-I_PDF-E/raw.md @@ -0,0 +1,430 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.1350** + +(10/2016) + +SERIES L: ENVIRONMENT AND ICTS, CLIMATE +CHANGE, E-WASTE, ENERGY EFFICIENCY; +CONSTRUCTION, INSTALLATION AND PROTECTION +OF CABLES AND OTHER ELEMENTS OF OUTSIDE +PLANT + +# --- **Energy efficiency metrics of a base station site** + +Recommendation ITU-T L.1350 + +![ITU logo: A globe with a red lightning bolt, next to the text 'International Telecommunication Union'.](6ed175c791b5e156d9c98a8dbcc3318c_img.jpg) + +ITU logo: A globe with a red lightning bolt, next to the text 'International Telecommunication Union'. + +## ITU-T L-SERIES RECOMMENDATIONS + +## **ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT** + +## **OPTICAL FIBRE CABLES** + +| | | +|-------------------------------------|-------------| +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | + +## **OPTICAL INFRASTRUCTURES** + +| | | +|-------------------------------------------------------|-------------| +| Infrastructure including node element (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | + +## **MAINTENANCE AND OPERATION** + +| | | +|-------------------------------------------------|-------------| +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | + +## **PASSIVE OPTICAL DEVICES** + +| | | +|--|-------------| +| | L.400–L.429 | +|--|-------------| + +## **MARINIZED TERRESTRIAL CABLES** + +| | | +|--|-------------| +| | L.430–L.449 | +|--|-------------| + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1350 + +# Energy efficiency metrics of a base station site + +## Summary + +Recommendation ITU-T L.1350 contains basic definitions of energy efficiency metrics, to evaluate the energy efficiency of a base station site including the energy consumption for: + +- the telecom equipment inside the base station site e.g., backhaul and base station equipment; +- the entire infrastructure, including cooling systems, monitoring systems (for power consumption, equipment running status, environment parameters, etc.), fire protection and lighting systems for all the sites; +- energy losses due to AC/DC rectifiers, generator and cable losses. + +The following energy factors will be considered for the evaluation: + +- electric energy from a public grid; +- electric energy generated by generators such as diesel generators for emergency or normal operation purposes; +- renewable energy. + +Measurement methodologies for the parameters considered in the metrics proposed are contained in other ITU-T Recommendations of the same series. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.1350 | 2016-10-07 | 5 | 11.1002/1000/12883 | + +## Keywords + +Energy efficiency, metric, radio site facilities. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2017 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|----------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation ..... | 2 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 2 | +| 6 Base station site definition..... | 3 | +| 7 Energy efficiency metrics for base station sites ..... | 4 | +| 7.1 Base station site energy efficiency assessment ..... | 5 | +| 7.2 Use of the metric ..... | 6 | +| 8 Data collection basic requirement ..... | 6 | +| 8.1 Test instrument requirements ..... | 6 | +| 8.2 Observation period ..... | 7 | +| 8.3 Measurement of energy consumption ..... | 7 | +| Bibliography..... | 8 | + + + +# Recommendation ITU-T L.1350 + +# Energy efficiency metrics of a base station site + +# 1 Scope + +This Recommendation specifies principles and concepts of energy efficiency metrics used to evaluate the energy efficiency of a base station site considering the energy consumption for: + +- the telecom equipment inside the base station site e.g., backhaul and base station equipment; +- the entire infrastructure, including cooling systems, monitoring systems (for power consumption, equipment running status, environment parameters, etc.), fire protection and lighting systems for all the sites; +- energy losses due to AC/DC rectifiers, generators and cable losses. + +This Recommendation shall not be used to evaluate the energy efficiency of equipment that are covered by other Recommendations such as [ITU-T L.1310] and [ITU-T L.1320]. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T L.1310] Recommendation ITU-T L.1310 (2014), *Energy efficiency metrics and measurement methods for telecommunication equipment*. + +[ITU-T L.1320] Recommendation ITU-T L.1320 (2014), *Energy efficiency metrics and measurement for power and cooling equipment for telecommunications and data centres*. + +[ITU-T L.1330] Recommendation ITU-T L.1330 (2015), *Energy efficiency measurement and metrics for telecommunication networks*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 active energy** [b-IEC 60050-131]: Integral of the instantaneous power $p$ over a time interval $[t_1, t_2]$ + +$$W = \int_{t_1}^{t_2} p \, dt$$ + +Note that the coherent international system (SI) unit of active energy is the joule (J). Another unit is the Watt hour (Wh). The kilowatt-hour (kWh) is commonly used for billing consumers of electric energy and is therefore indicated on electric energy meters. + +**3.1.2 backhaul equipment** [ITU-T L.1330]: Equipment used to connect base stations (BSs) to the core network, or to other BSs (such as X2 in LTE). + +**3.1.3 base station (BS)** [ITU-T L.1330]: A generic term used for a network component which serves one or more cells and interfaces the user terminal (through air interface) and a radio access network infrastructure. + +**3.1.4 energy** [ITU-T L.1330]: Capacity for doing work; having several forms that may be transformed from one to another, such as thermal (heat), mechanical (work), electrical or chemical, expressed in Joules. For the purpose of this Recommendation, energy will be expressed in Watt-hours (Wh) or kilowatt-hours (kWh). + +**3.1.5 mobile network operator (MNO)** [ITU-T L.1330]: An operator that manages one or more mobile networks. + +**3.1.6 power** [ITU-T L.1330]: The rate at which energy is transmitted. Power is measured in units of Watts. + +## **3.2 Terms defined in this Recommendation** + +This Recommendation defines the following terms: + +**3.2.1 energy efficiency (EE)**: The relation between the useful output and energy consumption. + +**3.2.2 infrastructure (facility)**: Equipment that supports the ICT equipment functionality providing energy, cooling and site ancillary activity, e.g., power delivery components and cooling system components. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|--------------------------------------------| +| BS | Base Station | +| EE | Energy Efficiency | +| GSM | Global System for Mobile communication | +| ICT | Information and Communications Technology | +| KPI | Key Performance Indicator | +| LTE | Long Term Evolution | +| MNO | Mobile Network Operator | +| PUE | Power Usage Effectiveness | +| SEE | Site Energy Efficiency | +| UMTS | Universal Mobile Telecommunications System | + +# **5 Conventions** + +This Recommendation uses the following conventions: + +| | | +|----------|--------------------------------------------------------------| +| $E_{CT}$ | Base station telecommunications equipment energy consumption | +| $E_{FE}$ | Electrical energy locally generated | +| $E_{GE}$ | Electrical energy from a public grid | +| $E_{TS}$ | Total site electrical energy consumption | + +# 6 Base station site definition + +The base station (BS) site is the mobile network physical site used to guarantee the coverage of a certain area providing the user accessibility to a radio mobile service. + +The base station site can be classified in different ways depending on the location: urban or rural and on the technologies present in the site: global system for mobile communication (GSM), universal mobile telecommunications system (UMTS), etc. + +A shared site is considered only as a single entity without allocating energy consumption to each operator/service present at the site. + +The base station site under investigation shall include all the equipment necessary for the full functionality of a radio site. + +![Diagram of a base station site showing telecom and site facility equipment.](367926125450c2bc3f4bdca9d59a62ba_img.jpg) + +The diagram illustrates the components of a base station site. A large box labeled "Telecom site (excluding power generation equipment)" contains two main groups of equipment. The first group, labeled "Telecom equipment" in blue, contains boxes for "RF", "Baseband", and "Backhaul", with a "Network connection" line extending from the "Backhaul" box. There are also boxes for "RF" and "RF feeder" shown with antenna symbols. The second group, labeled "Site facility equipment", contains four boxes: "Rectifier (AC/DC)", "Power backup", "Security lights, etc.", and "Air-conditioning". Three external energy sources are shown on the left: "Telecom equipment electrical energy (ECT)", "Site electrical energy (ETS)", and "Electricity generation". Arrows indicate that ECT is supplied to the "Telecom equipment" and ETS is supplied to the overall site, while "Electricity generation" is supplied to the "Site facility equipment". The label "L.1350(16)\_F01" is in the bottom right corner. + +Diagram of a base station site showing telecom and site facility equipment. + +**Figure 1 – Elements of a base station site example** + +Figure 1 shows an example of the equipment present in a base station site and includes telecom equipment and site facility equipment such as rectifiers, power backup, air conditioning and other site housekeeping equipment. + +The radio base station site as described above includes no local electricity generation. + +In some cases telecom sites may include local electricity generation: + +- Electrical energy generated at the site by diesel or other types of generators. +- Locally produced electricity from renewable sources (solar, wind, etc.). + +In order to operate the site, electricity has to be provided. + +The energy needed to operate a telecom site is typically provided in the form of electricity by a utility organization. + +A site can also be equipped with own electricity generation as shown in Figure 2. + +![Figure 2 – Electricity generation for a telecom site. The diagram shows energy flows from external sources into a 'Telecom site' box. External sources include 'Electrical energy from utility (E_GE)' (via a dashed line), 'Renewable power plant' (via a 'Transport - grid' line), 'Utility power plant' (via a solid line), 'Non-renewable energy' (via a solid line), and 'Other energy from utility' (via a dashed line). Inside the 'Telecom site (including local power generation equipment)' box, 'Renewable' and 'Genset' sources feed into 'Locally produced electrical energy (E_FE)'. 'Electrical energy from utility (E_GE)' and 'Locally produced electrical energy (E_FE)' both feed into 'Site electrical energy (E_TS)'. Finally, 'Site electrical energy (E_TS)' feeds into the 'Telecom site (excl. power generation)' box. The diagram is labeled 'L.1350(16)_F02'.](a5ee5c23b6dc52ec1d724b76d5a5f58f_img.jpg) + +Figure 2 – Electricity generation for a telecom site. The diagram shows energy flows from external sources into a 'Telecom site' box. External sources include 'Electrical energy from utility (E\_GE)' (via a dashed line), 'Renewable power plant' (via a 'Transport - grid' line), 'Utility power plant' (via a solid line), 'Non-renewable energy' (via a solid line), and 'Other energy from utility' (via a dashed line). Inside the 'Telecom site (including local power generation equipment)' box, 'Renewable' and 'Genset' sources feed into 'Locally produced electrical energy (E\_FE)'. 'Electrical energy from utility (E\_GE)' and 'Locally produced electrical energy (E\_FE)' both feed into 'Site electrical energy (E\_TS)'. Finally, 'Site electrical energy (E\_TS)' feeds into the 'Telecom site (excl. power generation)' box. The diagram is labeled 'L.1350(16)\_F02'. + +**Figure 2 – Electricity generation for a telecom site** + +The base station site typically includes: base station equipment, backhaul equipment, cooling equipment such as air conditioning units, a rectifier system and renewable energy solutions such as solar, wind energy systems, etc. + +The metrics developed in this Recommendation consider a base station site that normally includes the following types of equipment: + +- Telecommunication equipment. +- Site equipment (e.g., air conditioners, rectifiers, batteries, safety and monitoring equipment). + +This equipment can exist as separate items of equipment or can be integrated into one or more physical units depending on the solution and base station site type, e.g., an indoor or an outdoor site. + +Power and energy efficiency metrics and measurements for individual site elements of base stations are described in several ITU-T Recommendations, such as [ITU-T L.1310] for radio base stations and [ITU-T L.1320] for power and cooling equipment. + +This Recommendation instead describes metrics for base station site energy efficiency in operational states. + +# 7 Energy efficiency metrics for base station sites + +Energy efficiency has become an important issue for base station sites, where specific performance metrics, requirements and technologies to improve energy efficiency must be taken into consideration. + +For site infrastructure, a simple metric used to verify the efficiency of base station site facilities is considered sufficient and has the advantage of being relatively simple to calculate as well as allowing remote measurements to be carried out. + +Renewable energy usage is considered an important factor to reduce the effect of climate change. Consumption of more energy from renewable sources including local or dedicated grid power and the use of fuels with lower carbon contents are ways to reduce carbon emissions. Electricity from renewable energy sources shall be included in the total energy consumption on site. + +The site energy efficiency (SEE) metric described in this Recommendation helps mobile network operators (MNOs) to assess important sustainability aspects on cell sites as well as helping them to compare results and determine opportunities to increase energy efficiency or reduce power consumption. + +The total energy consumption of the base station site will include the grid electricity as well as local energy sources such as diesel generators or solar systems. + +## 7.1 Base station site energy efficiency assessment + +Clause 7.1.1 defines the metric proposed for a base station site energy efficiency assessment. Figure 3 shows a base station site diagram illustrating the energy measurement points considered in this Recommendation. + +![Figure 3: An example of a radio base station site with energy flow and measurement points. The diagram shows energy flow from three sources (Grid electric energy, Fuel energy, and Renewable energy) through various components. Grid energy flows to E_GE, then to Infrastructure such as AC/DC. Fuel energy flows to On site generation (fuel), then to E_FE, then to AC/DC power supply. Renewable energy flows to On site generation (renewable), then to E_FE, then to AC/DC power supply. The AC/DC power supply flows to E_CT, then to Base station equipment and Backhaul equipment. A Battery is connected to the AC/DC power supply. The Base station equipment and Backhaul equipment are connected to a Coverage area. The diagram is labeled L.1350(16)_F03.](5a4e62bead259c258d069fd3663ea670_img.jpg) + +Figure 3: An example of a radio base station site with energy flow and measurement points. The diagram shows energy flow from three sources (Grid electric energy, Fuel energy, and Renewable energy) through various components. Grid energy flows to E\_GE, then to Infrastructure such as AC/DC. Fuel energy flows to On site generation (fuel), then to E\_FE, then to AC/DC power supply. Renewable energy flows to On site generation (renewable), then to E\_FE, then to AC/DC power supply. The AC/DC power supply flows to E\_CT, then to Base station equipment and Backhaul equipment. A Battery is connected to the AC/DC power supply. The Base station equipment and Backhaul equipment are connected to a Coverage area. The diagram is labeled L.1350(16)\_F03. + +**Figure 3 – An example of a radio base station site with energy flow and measurement points** + +Figure 3 does not take into account the fact that the power system is always a separate entity with respect to the telecom equipment, nor does it take into account the following configurations: + +- the AC/DC conversion may be integrated into the telecom part and the air cooling unit may be not present, e.g., for a pole mounted base station site. +- The battery may be present if power backup is required. +- Multiple functions (telecom AC/DC conversion, battery and cooling) may be integrated in a single box as is typical for outdoor equipment. +- Functions may be realized as separate physical units. + +### 7.1.1 Site energy efficiency metric definition + +Site energy efficiency (SEE) represents the site efficiency of the measured site. + +Site energy efficiency (SEE) is the ratio between the total energy consumption of telecommunication equipment and the total energy consumption on site: + +$$SEE = \frac{E_{CT}}{E_{TS}} \times 100\%$$ + +NOTE – The definition proposed here is selected employing the same philosophy as the power usage effectiveness (PUE) indicator used in data centre technologies. + +The total energy consumption of telecommunication equipment is indicated as $E_{CT}$ in Figure 3. $E_{CT}$ is the energy consumption of telecommunications equipment present in the base station site under consideration during the measurement time period. + +$E_{TS}$ is the sum of different input energy sources such as from a public grid, a diesel generator present on the site or from a different type of local generator or a renewable energy source, etc. $E_{CT}$ , $E_{GE}$ and $E_{FE}$ are shown in Figures 2 and 3: + +$$E_{TS} = E_{GE} + E_{FE}$$ + +Where: + +$E_{CT}$ is the energy consumption of telecommunications equipment present in the base station site under consideration during the measurement time period + +$E_{GE}$ is the input electric energy (in kWh) from the public grid during the measurement time period + +$E_{FE}$ is locally produced electrical energy (in kWh) generated by a genset or other type of local generator with a renewable energy source on the site during the measurement time period. + +## 7.2 Use of the metric + +The metric defined in this Recommendation can be used by telecommunication operators to check their installations for different purposes; some possible uses are outlined as follows: + +- To verify the effect of implementing some action in a base station site by simply calculating using the metric before and after the action. +- To verify an analysis on different sites and find out which sites are more relevant to plan an intervention with a view to obtaining an improved value for the metric. +- To verify the metric values by using a monitoring system for radio site facilities to find out if there is a variation of the metric in the same site. A variation can be considered as an indication of degradation in performance of a base station site facilities component signalling the need for preventive maintenance. +- As an indicator for the selection of an integrated site power solution. + +# 8 Data collection basic requirement + +International standards shall be used to measure the data necessary for SEE calculation. In cases where international standards are not available, the data used for the assessment using the metric defined in this Recommendation shall be collected as defined in this clause. + +## 8.1 Test instrument requirements + +The testing equipment accuracy shall be in line with the requirements outlined in Table 1. + +**Table 1 – Testing equipment accuracy requirements** + +| Item | Accuracy | +|-----------------|------------------------------------------------| +| Temperature | $-0.5^{\circ}\text{C}\sim+0.5^{\circ}\text{C}$ | +| Humidity | $-5.0\%\sim+5.0\%$ | +| Voltage | $-1\%\sim+1\%$ | +| Current | $-1\%\sim+1\%$ | +| Electric energy | Class 1 | +| Weight | $-1\%\sim+1\%$ | +| Volume | $-1\%\sim+1\%$ | + +NOTE – Class 1 is for energy measurement accuracy and should refer to class 1 of [b-IEC 62053-21]. +NOTE – The accuracy of voltage and current measurements are defined in [ITU-T L.1320]. + +## 8.2 Observation period + +Examples of factors that will influence the metrics for assessment of energy efficiency on cell sites include: + +- The number of users covered by the cell site. +- Climate conditions such as the temperature and humidity of the site and target environmental requirements. + +The metric of energy efficiency varies with seasonal and load variances. Increasing the minimum frequency of the measurement provides a larger and more accurate data set to analyse. Continuous real-time monitoring can be one option to manage the site efficiency so that historical trending and statistical analysis can be carried out. + +Other benefits of continuous real-time monitoring include early detection of unexpected variations that could indicate systems issues. In cases where continuous real-time monitoring is not practical or economically justifiable, some form of repeatable, defined process should be in place to capture the metric value as often as possible for comparison purposes. + +When reporting metric values, cell site owners should use the average SEE measured over a one-year period. For cell sites without real-time monitoring, the metric of energy efficiency should be collected in a repeatable fashion and the methodology documented for review. + +## 8.3 Measurement of energy consumption + +Measurement of $E_{GE}$ should use kilowatt-hour (kWh) meters that report the active energy. $E_{CT}$ can be the mathematical product of volts, amperes and the timeframe of the measurement duration as power delivery provides direct current (DC). The measurement point of the $E_{CT}$ should be at the power feeding interface of the telecommunication equipment considering the energy losses of the cable. + +The energy provided by a public grid can be measured by means of metering information provided by utility suppliers or by mobile network integrated measurement systems [b-ETSI ES 202 336-12]. The energy generated locally can be measured by the meters installed in site. Moreover, sensors can be used to measure site and equipment energy consumption. + +The measurement point of energy consumption of $E_{GE}$ , $E_{CT}$ and $E_{FE}$ should reference Figure 2 and Figure 3. + +# Bibliography + +- [b-ITU-T L.1340] Recommendation ITU-T L.1340 (2014), *Informative values on the energy efficiency of telecommunication equipment.* +- [b-ITU-T L.1410] Recommendation ITU-T L.1410 (2014), *Methodology for environmental life cycle assessments of information and communication technology goods, networks and services.* +- [b-ETSI ES 202 336-12] ETSI ES 202 336-12 (2015), *Environmental Engineering (EE); Monitoring and control interface for infrastructure equipment (power, cooling and building environment systems used in telecommunication networks); Part 12: ICT equipment power, energy and environmental parameters monitoring information model.* +- [b-IEC 62053-21] IEC 62053-21:2003, *Electricity metering equipment (a.c.) –Particular requirements – Part 21: Static meters for active energy (classes 1 and 2).* +- [b-IEC 60050-131] IEC 60050-131:2002, *International Electrotechnical Vocabulary – Part 131: Circuit theory.* + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for 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+|--------------------------------------------------------|-------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node elements (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1370 + +# Sustainable and intelligent building services + +## Summary + +The concept of sustainable intelligent building (SIB) is closely related to efficiency and environmentally-aware practices. The concept is therefore the key enabler of the sustainability of the building itself, and of the city as a whole. Recommendation ITU-T L.1370 sets the minimal requirements for the efficient and sustainable management of the building as a unit. The sustainability of human activities in urban areas cannot be addressed without taking into consideration the building, which is the most basic unit that cities are composed of. + +This Recommendation also defines the services enabled by the SIB concept, the way it contributes to the aforementioned goals of sustainability, its features, its different possible functioning modes, or its internal architecture and requirements with the Internet of things (IoT) node at its core. + +Interoperability deserves a special mention among these requirements and specifications, as most of the added-value that the SIB provides comes into action when it interacts with other parts of the building, other buildings, city elements, or the city itself. Protocols, semantics, and normalization are key as a part of this interaction, and the SIB with its IoT node is required to be compliant with all of them. + +Extensibility is another key feature for the SIB and the IoT node. The technology behind smart and sustainable cities is currently evolving very quickly, as it is a state-of-the-art technological arena. That is the reason why one of the most important architectural patterns to take into consideration is to design a SIB and an IoT node that support not only upgrading, but also the capacity to accommodate new technologies, protocols, services and applications that may be relevant for the industry in the future. + +In addition to these clear advantages for the technical durability of the SIB infrastructure, this will enable as well the creation of an open "smart ecosystem", with third parties being able to integrate their own developments, expanding the capacities of the SIB, and ultimately contributing to improve the quality of life of citizens. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.1370 | 2018-11-13 | 5 | 11.1002/1000/13724 | + +## Keywords + +Energy efficiency, environment, structural stability, sustainability, sustainable building. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2019 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|----------------------------------------------------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 2 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 3 | +| 6 Description of a sustainable and intelligent building and its control by IoT node..... | 3 | +| 6.1 Sustainable and intelligent building concept..... | 3 | +| 6.2 Functioning modes of the SIB: standalone mode, in association with another SIB, or integrated with the smart city..... | 5 | +| 7 Building IoT node: concept and structure ..... | 6 | +| 7.1 Basic structure ..... | 6 | +| 7.2 Building IoT node functional needs ..... | 7 | +| 7.3 Building IoT node requirements..... | 8 | +| 8 Relationships of the SIB with other buildings..... | 9 | +| 9 Relationships of the SIB with the city ..... | 10 | +| Appendix I – Examples of interaction between SIB and other systems ..... | 11 | +| I.1 Fire detection case ..... | 11 | +| I.2 Pollution ..... | 11 | +| I.3 Water losses..... | 11 | +| I.4 Earthquakes ..... | 11 | +| Bibliography..... | 13 | + + + +# Recommendation ITU-T L.1370 + +# Sustainable and intelligent building services + +# 1 Scope + +This Recommendation sets out the services and data required for a sustainable and intelligent building to improve the quality of life of citizens, as well as the specification of its functional features and the technical requirements to be met by the device that provides these services and data. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T Y.4200] Recommendation ITU-T Y.4200 (2018), *Requirements for the interoperability of smart city platforms*. + +[ITU-T Y.4201] Recommendation ITU-T Y.4201 (2018), *High-level requirements and reference framework of smart city platforms*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 big data** [b-ITU-T Y.3600]: A paradigm for enabling the collection, storage, management, analysis and visualization, potentially under real-time constraints, of extensive datasets with heterogeneous characteristics. + +NOTE – Examples of dataset characteristics include high-volume, high-velocity, high-variety, etc. + +**3.1.2 city** [b-ITU-T Y.4900]: An urban geographical area with one (or several) local government and planning authorities. + +**3.1.3 city platform** [ITU-T Y.4201]: A computer system or integration of computer systems that , uses information and communication technologies (ICTs) to access data sources and process them to offer urban operation and services to the city. + +NOTE – The concept is extended to a community. + +**3.1.4 Internet of things (IoT)** [b-ITU-T Y.4000]: A global infrastructure for the information society, enabling advanced services by interconnecting (physical and virtual) things based on existing and evolving interoperable information and communication technologies. + +NOTE 1 – Through the exploitation of identification, data capture, processing and communication capabilities, the IoT makes full use of things to offer services to all kinds of applications, whilst ensuring that security and privacy requirements are fulfilled. + +NOTE 2 – From a broader perspective, the IoT can be perceived as a vision with technological and societal implications. + +**3.1.5 interoperability** [b-ITU-T Y.101]: The ability of two or more systems or applications to exchange information and to mutually use the information that has been exchanged. + +**3.1.6 open interface** [ITU-T Y.4201]: A public standard for connecting hardware to hardware and software to software. Open interfaces are designed and documented for safe and easy use by third party developers and freely available to all. + +**3.1.7 smart city platform (SCP)** [ITU-T Y.4201]: A city platform that offers direct integration of city platforms and systems, or through open interfaces between city platforms and third parties, in order to offer the urban operation and services supporting the functioning of city services, as well as efficiency, performance, security and scalability. + +**3.1.8 smart sustainable city (SSC)** [b-ITU-T Y.4900]: A smart sustainable city is an innovative city that uses information and communication technologies (ICTs) and other means to improve quality of life, efficiency of urban operation and services and competitiveness, while ensuring that it meets the needs of present and future generations with respect to economic, social, environmental and cultural aspects. + +## **3.2 Terms defined in this Recommendation** + +This Recommendation defines the following terms: + +**3.2.1 sustainable and intelligent building (SIB)**: A concept that includes a building with all its internal premises and systems, and also the surrounding area that has an impact on the building. In the concept of SIB, energy aspects are especially relevant when considering sustainability. The SIB's configuration can be either as an isolated building, or as a building linked to other SIBs in its proximity (with which it may share resources), or as a city element. + +**3.2.2 Internet of things (IoT) node**: The equipment located in the SIB that interfaces with the city platform, other IoT nodes, external data sources, or internal data sources (sensors in the building or the surrounding area). + +**3.2.3 open standards**: Standards made available to the general public and which are developed (or approved) and maintained via a collaborative and consensus driven process. + +NOTE – Open standards facilitate interoperability and data exchange among different products or services and are intended for widespread adoption. + +**3.2.4 Java**: General purpose object oriented class based computer programming language. + +**3.2.5 sandbox concept**: A set of security rules that are used to prevent the IoT from executing certain functions when they are not allowed to do so. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-----------|------------------------------------------| +| API | Application Programming Interface | +| BMS | Building Management System | +| CO | Carbon Oxide (monoxide) | +| ICT | Information and Communication Technology | +| IoT | Internet of Things | +| IT | Information Technology | +| Java OSGI | Java Open Service Gateway Initiative | +| KPI | Key Performance Indicator | +| LDAP | Lightweight Directory Access Protocol | +| MEMS | Micro-Electro Mechanical Sensors | + +| | | +|-------|--------------------------------------| +| MQTT | Message Queuing Telemetry Transport | +| OAuth | Open Authentication | +| REST | Representational State Transfer | +| SCP | Smart City Platform | +| SIB | Sustainable and Intelligent Building | +| SSC | Smart Sustainable City | + +# 5 Conventions + +None. + +# 6 Description of a sustainable and intelligent building and its control by IoT node + +## 6.1 Sustainable and intelligent building concept + +An SIB building provides services and data that can contribute to improve the quality of life of citizens and the sustainability of human activities. Usually, this information is very useful for the cities, but the SIB can also contribute to these goals without interfacing with any other city element, and by considering the building just from an isolated perspective. For all of these purposes, the SIB shall meet some specifications regarding its functional features and technical requirements. + +Although the services provided by the SIB can be very diverse, the scope of this Recommendation only highlights those that are considered as basic services with high added value: + +- **Pollution information:** The building can work as a powerful sensor of air pollution levels (both at street level and at roof level), noise pollution levels, and water pollution levels. This information enables the monitoring of the principal key performance indicators (KPI) taken into account for analysing the sustainability of cities. +- **Consumption of public services:** The SIB can also be considered as an information source that provides the city with data related to the consumption of the basic public services, such as electric power, water, fuel gas and diesel. In the case of electric power, the SIB also provides the city with information on the electric power generated by the SIB and the capacities and status of its own energy storage. This information will be used by the city to improve the power supply efficiency. Given the structure of the cities, distribution networks define how public services are provided and operated; the aggregation of the public services provided to the buildings, neighbourhoods, districts, etc., is a valuable mean to understand the use that is made of these services, and will help to redesign and/or expand the distribution networks and the provision of services in certain areas. +- **Events and crisis management:** From a reactive point of view, in a critical or anomalous situation (fires, high occupancy levels, floods, gas leaks, spills of dangerous substances, level of CO2 in garages, etc.), the building is an essential element that provides the city with contextual information for the management of events in the urban area. +- **Seismic and structural stability information:** As a constructive element, the building is one of the most important elements in seismic risk management. It provides valuable information about structural stability by using types of sensors such as micro-electro mechanical sensors (MEMS), inclinometers, crack meters, temperature sensors for structures, etc. +- **Mobility management:** As the element of the city where people develop most of their activity (working, sleeping, etc.), the SIB is a key element for defining the flows of people through the city. It is able to provide information such as the number of inhabitants of the building, the number of persons at a given time, or the number of vehicles within the building, + +etc. All of this information is relevant for handling the challenge of managing mobility and controlling the CO2 emissions caused by vehicles. + +- **Energy efficiency:** As a consumer, producer and energy operator, the SIB is a key element regarding energy efficiency. It can provide valuable information and can adapt the SIB behavior to the needs of the city or the building itself, taking into account sustainability, savings, or any other predefined criteria. + +Likewise, smart Wi-Fi data usage and entertainment systems present in the IoT node can provide useful information for profiling the citizens and their habits, taking into account privacy and data protection compliance requirements (e.g., the General Data Protection Regulation (GDPR) [b-EU 2016/679] in the case of European countries). + +In addition to these basic services, the building will provide other services such as parking, number of persons being hosted, lift management, etc. + +These basic services with high added value could lead not only to the development of eco-rating schemes or programs that will help the city as a whole, but they will also help end-users to make better choices based on reliable information which will ultimately promote sustainability and environmentally aware behaviours to the benefit of the city and its citizens. Beneficially, the citizen will be empowered in terms of energy, health and mobility management. + +### 6.1.1 Sustainable and intelligent building and energy efficiency + +The cost of electricity is a main consideration to be taken into account for the purpose of cost reduction. The SIB shall have real-time data of the cost of electricity (to be provided by suppliers). This will contribute to the awareness in terms of energy consumption. + +NOTE – Real-time implies the fastest possible response depending on the country's infrastructure. + +An energy consumption analysis can be done at the SIB level. From the perspective of the SIB, energy consumption is related to heating and lighting. By means of the IoT node and its functionality, the SIB will be able to analyse energy consumption and make the best decision in order to maximize sustainability. + +The SIB will have different energy inputs and a control logic as well as information on the different commercial offers of all the companies that offer energy supply to the building, as well as the different available energy sources (solar, geothermal, wind, heat pumps, etc.) and energy storages (batteries, heat tank, etc.), and will support the possibility of selling energy surplus. With all this information and the control logic provided by the SIB, the building manager will be in a position to make decisions based on savings, sustainability, or any other criteria. Additionally, the unified system that provides the users with access to these data will allow them to: + +- Monitor their own consumptions to prevent unexpected increase. This will enable users to reduce their bills, which in some cases will be at the expense of their comfort. +- Maximize sustainability by reducing the impact on the environment, promoting the awareness that energy inefficient consumption is directly translated into CO2 emissions. + +Energy suppliers will be able to manage and monitor energy counters remotely, and they will also have access to consumption data, which will allow them to: + +- Estimate consumption forecasts. +- Profile their customers and provide them with appealing commercial offers. This will help in consumption management as well. +- Improve fraud detection and prevention. + +The SIB enables energy efficiency and promotes the use of green sustainable energy. The contribution of the SIB to a more efficient approach to energy consumption will have a positive impact on + +sustainability to the benefit of the environment and the citizens, and thus contributing to reduce the carbon footprint. + +## **6.2 Functioning modes of the SIB: standalone mode, in association with another SIB, or integrated with the smart city** + +The IoT node is at the core of the SIB. The functioning of this IoT node will be described in clause 6.3. + +A variety of use cases can take advantage of the SIB's definition, bearing in mind that the area of influence of the building goes beyond its physical limits. These use cases will be related to data that affect the building somehow, and can range from information on surface parking slots to a pollution sensor located on the rooftop, passing through geothermal information, solar installations, energy excesses management in conjunction with adjacent buildings inside the same complex, etc. + +The SIB will collect all of this information, it will process and enrich it, and finally it will execute any logic based on the analysis of the data. The most typical scenarios for the isolated mode are scenarios in which interfacing with other buildings or the city is not necessary. These scenarios include use cases such as: + +- controlling supplies, +- making decisions and taking actions to reduce costs, +- activating emergency or building evacuation plans, +- controlling temperatures inside the building and interfacing with air-conditioned or heating installations, +- controlling lighting based on daytime and the presence of people in different areas of the building, +- enabling mobility inside the building in cases of mass-presence or overcrowded situations, etc. + +The first functioning mode of the SIB is a standalone mode. The SIB works in an independent way and it does not interface with other SIBs or city elements. Notwithstanding, even in a standalone mode, the SIB is required to be integrated with the building internal systems, ranging from escalator networks, to lifts or temperature control systems, among others, and specially being capable of weighting and identifying the different destinations of energy consumption. The SIB collects data in order to have the capacity to analyse and make decisions, but it does not necessarily need to be a controller, as there may already be specific management systems that control these internal systems of the building. In spite of this, the SIB may optionally control and operate these systems. As a result of all the available information, the SIB has the capacity to analyse patterns of usage, implement predictive models at SIB-level, and contribute to the improvement of consumption habits of the citizens. + +The second functioning mode of the SIB is its association with other SIBs allowing it to take on a secondary role of interfacing with another master SIB. In this configuration, from the master SIB's point of view, the secondary SIB plays the same conceptual role as an external data source. For the interface between SIBs, a bidirectional data link is needed to support the flow of data exchange. + +The third functioning mode of the SIB is as an element of the smart city. In this capacity, the SIB adds value both as a building and as a part of a group of buildings that provide data. The SIB can be considered as a basic city element that can help to provide valuable and relevant information to achieve the aforementioned goals. In this regard, it maximizes efficiency in the use of resources, and contributes to protect citizens, including their health and well-being. It also helps to minimize the negative impacts of human activities, such as waste, inefficient energy consumption and pollution. + +Once the information is provided by the SIB at a city level, it can be aggregated with other SIBs' data, and then it can be used to define city or district maps showing pollution levels, energy or water consumption per capita and rent, population density and presence, generation of waste based on + +different segmentation factors, such as, family incomes, etc. These maps will be very valuable when used as an economic and social assessment to design new strategies and city plans with much greater effectiveness. + +For instance, in terms of energy efficiency, the SIB not only collects data from its sensors and devices, but it also enriches this data with context information such as the number of tenants, usage profiles, localization, etc. This is an additional enrichment of information that has already added value at the SIB level and maximizes its value with the use cases in which the SIB sends its data to other buildings, public city elements, and/or the city itself. With this information, city actors that generate and consume electricity can be coordinated, which optimizes the use of energy, helps to formulate energy management plans, and even the design and the expansion of the power supply network (or its redesign). For the two former non-standalone modes, the interfacing of the SIB with other city elements requires a bidirectional communication and data exchange, which will support both the building manager and the city in decision-making processes. + +For interfacing with the smart city, the data shall be exchanged using the normalized interfaces defined in [ITU-T Y.4201]. These will be addressed in the following clauses. + +# 7 Building IoT node: concept and structure + +All SIB's services and data will be provided through the IoT node. The IoT node is an equipment that is the main enabler of all these functionalities at the SIB level. It collects data from the different sources, and enriches the data, stores them, interfaces with other SIBs and with the city. For all these interfaces, it is key that the IoT node implements well-defined semantics, which shall consider the whole range of use cases. These semantics will contribute to a layer of standardization that is critical to ensure interoperability between different vendors, either inside the building itself, or when communicating with other city elements. By means of the IoT node, the SIB will also be able to interface with sensors, actuators and communications. This way, the IoT node will be able to detect different scenarios, and react to them, thus incrementing the resilience of the building. + +## 7.1 Basic structure + +The building IoT node, in the context of the SIB, is an element for communication and processing of information that will be implemented according to the structure described in Figure 1, and that is required to offer the following capabilities: + +- **interact with city elements:** The IoT node enables the building to be integrated into the city and interact its elements in a secure way. The building will provide information to other urban entities and it can take decisions, or to carry out specific actions in collaboration with other elements of the city. +- **Communicate with all elements of the building:** The building IoT node, as an enabler, can interact with the elements contained in it by specific actuators or sensors (measures basic services, infrastructure sensors, technical alarms, atmospheric sensors, etc.) in a secure way. +- **Interact with the systems and private networks of the building:** The building can be considered as a set of systems and networks which can interact with it. The IoT node shall have the capacity to communicate with these systems and private networks. +- **Process and infer information:** The IoT node shall be able to gather the information, aggregate it and perform rules and procedures locally according to the edge-computing paradigm. This feature is key for allowing the delegation of certain tasks (mainly critical and near real-time ones) from the smart city, filtering and improving the information with more detail and providing value added services. +- **Update and upgrade:** The IoT node shall include updating capabilities in terms of new service accommodation, new application accommodation and communication protocol + +extension and upgrading. In this sense, the IoT node shall be able to adapt to new services and technologies. + +![Figure 1 – Building IoT node structure. The diagram shows a central IoT node structure with internal components and external connections. The internal components are Security, Core processor, Multiprotocol (Standardized, open, interoperable), and Acquisition/interconnection level. External connections include Broadband, Service provider networks, Sensors/actuators, Specified control networks, and Buildings. A label L.1370(18)_F01 is present in the bottom right corner of the diagram area.](4e4be0bd8b235167902f2c03e41da651_img.jpg) + +The diagram illustrates the internal structure of a Building IoT node. It consists of four main internal components: 'Security' (top left), 'Core processor' (bottom left), 'Multiprotocol (Standardized, open, interoperable)' (top right), and 'Acquisition/interconnection level' (bottom right). The node is connected to external entities via double-headed arrows: 'Broadband' and 'Service provider networks' on the left, and 'Sensors/actuators', 'Specified control networks', and 'Buildings' on the right. A label 'L.1370(18)\_F01' is located in the bottom right corner of the diagram area. + +Figure 1 – Building IoT node structure. The diagram shows a central IoT node structure with internal components and external connections. The internal components are Security, Core processor, Multiprotocol (Standardized, open, interoperable), and Acquisition/interconnection level. External connections include Broadband, Service provider networks, Sensors/actuators, Specified control networks, and Buildings. A label L.1370(18)\_F01 is present in the bottom right corner of the diagram area. + +**Figure 1 – Building IoT node structure** + +## 7.2 Building IoT node functional needs + +To cover all of the aforementioned needs, it is required that the IoT node is appropriately sized. It will have enough processing power and storage capacity to process the local information, to buffer this information in the absence of connectivity (mitigating the risks of data loss), and to transform it into valuable data that allows decisions to be made (both locally and remotely). The following functional needs have been identified: + +- **Communications and connectivity:** The IoT node shall have the connectivity (both internal and external) required to provide the basic services by using open and, as far as possible, standardized protocols. +- **Storage:** The IoT node will store different data according to needs. It is recommended to use static storage such as solid state drive to increase the reliability and durability of the system. +- **Processing:** The node shall analyse and immediately process the information received from different sources, and it shall generate new triggers or signals that will be sent to other systems. Additionally, the node may use these processing capabilities to ensure the quality of the data gathered through the aggregation of different sources. +- **Security:** The IoT node should have the security elements, both software and hardware, which ensure: + - Integrity of the system and its data. + - Confidentiality of the sensitive information. + - Availability of information to third parties and ensure the capacity to reject connections not allowed. + - Authentication of source and destination. + - Codification of communications. + - Authorization to make use of the services and resources of the system by third parties, or to make use of the software deployed on it. +- **Software management:** The IoT node will have the capacity to manage and certify its software, and it will also supply the needed resources, both hardware and software, to support updating the software on all of its layers. This capacity shall be provided both locally and remotely. +- **Extendibility:** The IoT node will have the capacity to support specific third-party developments for local-based services. This will allow the possibility of creating new services based on the developed architecture. Additionally, the IoT node may include specific + +features and characteristics to allow hardware updates of the system in an easy way, for a smooth implementation of new protocols. + +## 7.3 Building IoT node requirements + +SIB requirements are classified in functional and technical requirements. + +### 7.3.1 Functional requirements + +It is recommended that, as an adaptation of the mentioned standard, platforms that integrate the information of the SIB support the following features or functions depending on the use-case: + +- **Integration:** The integration with other SIBs and city platforms through standardized application programming interfaces (APIs) and protocols (message queuing telemetry transport (MQTT), representational state transfer (REST), etc.) to enable bidirectional communication with IoT nodes or other systems., The requirements for the communications are described in subsequent sections. +- **Semantic rules:** IoT node is required to have the capacity to manage multiple semantic models of information. This capability is aimed at the mash-up application of information between different data domains and representations of the objects (entities) included in them. +- **Event interoperability:** It provides the necessary interfaces so that the events generated in the IoT node can trigger actions in the city platform and other connected external systems, as well as being able to send events internally to the IoT node to trigger actions inside the building, e.g., evacuation alarms. +- **Data standards:** The possibility to make available the generated information as open data to be used by other city systems or citizens. +- IoT node security has the following features: + - Supports, authentication and authorization. + - Controls access to the SIB and all of the elements accessed through this IoT node, such as, sensors, control centers, databases and applications. + - Ensures confidentiality in the communications with the SIB. + - Ensure confidentiality of access to data, so that each role can only view the data to which it has been authorized. + - Enables the definition and management of security policies. + - Manages the maintenance of users, roles, permissions and profiles. Central module and easy access (via web) to administer user management roles and permissions. + - Supports different authentication mechanisms such as user-based and password-based solutions, tokens, open authentication (OAuth), electronic certificates (from individuals, servers and applications) or other advanced solutions based, for example, on biometric techniques. + - Enables integration with existing user repositories in the public administrations, including, lightweight directory access protocol (LDAP) style repositories and user databases, among others. + - Gives the possibility of extension by adapting the security mechanisms in accordance to the needs of each city. + +### 7.3.2 Technical requirements + +It is required that the IoT node provides access to the information of at least a group of mandatory sensors in SIB (the access type can be a direct access to a sensor or through connection with a building management system (BMS) or legacy system) taking into account the following: + +- The IoT node shall be able to capture information from at least one specific energy consumption meter. +- The IoT node shall be able to capture information from at least one specific air quality and pollution sensor. +- The IoT node shall be able to capture information from at least one specific flowmeter for water service information collection. +- The IoT node shall be able to capture information from at least one fire detector. +- The IoT node shall be able to capture information from at least one flooding detector. +- The IoT node shall be able to capture information from at least one carbon oxide (monoxide) (CO) detector. +- The IoT node shall be able to capture information from at least one fire detector. + +In addition to this list of mandatory sensors for SIB, complementary services can be provided for additional value-added services and solutions, such as, building occupation measuring cameras, seismic detectors, etc. + +The IoT node to be installed in a SIB shall include basic and optional requirements depending on the use case. Technical specifications are recommended to guarantee the fulfilment of these functional requirements introduced previously and are listed below: + +- It is recommended that the IoT node includes a processor with at least two cores of at least 1 GHz processing speed to allow the smart functional requirement. + +NOTE – This relatively low performance, compared to high-end general use personal computers, is intended to profit from the very compact and low energy consumption of lower specification hardware specifically designed for IoT, and which may cover the needs of small buildings. Larger buildings may require a more powerful computer. + +- It is recommended that the IoT node includes a low-latency and solid-state drive mass memory up to 8 Gb to guarantee the performance of the system in non-communication situations during a certain amount of time. +- It is recommended that the IoT node provides wireless local area network connectivity through at least two protocols such as 802.11, 802.15 or Z-Wave, among others. +- It is recommended that the IoT node provides wired local area network connectivity through at least two protocols such as Ethernet, optics fiber or RS-485, among others. +- It is recommended that the IoT node provides at least one wired wide area network connectivity interface (for example, Ethernet) and one wireless wide area network connectivity interface (for example, 3G, 4G or NB-IoT). +- It is recommended that the IoT node provides specific frameworks for third-parties application and services deployment (for example, Java OSGI framework) through specific integration API, enabling the sandbox concept. + +# 8 Relationships of the SIB with other buildings + +The IoT node can work as an independent element of the city by providing information management to the building and offering services to the neighbours of the building. In this context, the IoT node collects the information from the sensors and triggers the actions, in case of critical situations, that are necessary to protect and safeguard the people. Although in this case, the IoT node does not communicate with the city platform, it can communicate with the rest of the nearby SIBs enabling + +collaboration between them and generating coordinated responses to events, such as environmental alerts, evacuation plans or safety closing in emergencies. + +# 9 Relationships of the SIB with the city + +![Diagram illustrating the relationships of the SIB with the city. On the left, a stylized city skyline is shown above a horizontal bar containing six vertical blue segments labeled: Economy, Mobility, Environment, People, Governance, and Living. On the right, a building with a magnifying glass is shown above a horizontal bar containing four vertical blue segments labeled: Pollution, Consumption, Sustainability, and Technical alarms. Below the building, a grey box labeled 'IoT node' is connected to the four segments. A line labeled 'Normalized data' connects the bottom of the city skyline bar to the IoT node. The text 'L.1370(18)_F02' is in the bottom right corner.](0f985b39edc1d52ba3600c438bc8f0a5_img.jpg) + +The diagram illustrates the integration of an Intelligent Building (SIB) into a smart city platform. On the left, a stylized city skyline represents the broader city ecosystem, with its core components categorized into six vertical blue bars: Economy, Mobility, Environment, People, Governance, and Living. On the right, a specific building is highlighted with a magnifying glass, representing the SIB. This building's internal focus areas are categorized into four vertical blue bars: Pollution, Consumption, Sustainability, and Technical alarms. Below these bars, an 'IoT node' is shown, which acts as a data processing and communication hub. A line labeled 'Normalized data' connects the city ecosystem's data to the IoT node. The text 'L.1370(18)\_F02' is located in the bottom right corner of the diagram. + +Diagram illustrating the relationships of the SIB with the city. On the left, a stylized city skyline is shown above a horizontal bar containing six vertical blue segments labeled: Economy, Mobility, Environment, People, Governance, and Living. On the right, a building with a magnifying glass is shown above a horizontal bar containing four vertical blue segments labeled: Pollution, Consumption, Sustainability, and Technical alarms. Below the building, a grey box labeled 'IoT node' is connected to the four segments. A line labeled 'Normalized data' connects the bottom of the city skyline bar to the IoT node. The text 'L.1370(18)\_F02' is in the bottom right corner. + +**Figure 2 – Intelligent building and the smart city platform** + +Inside a smart city ecosystem, the interoperable communication with third parties and with external elements as illustrated in Figure 2 shall comply with Recommendation [ITU-T Y.4200] that requires open and standardized interfaces. The SIB can be considered as an object of a smart city which, additionally to its own functions, shall provide information as an external infrastructure. The information should be in a standardized format to be understood by the city platform. + +This standard format of information shall comply with [ITU-T Y.4200]. This Recommendation should serve as a cornerstone for the effective development of communications between the different stakeholders involved in the smart cities. + +# Appendix I + +## Examples of interaction between SIB and other systems + +(This appendix does not form an integral part of this Recommendation.) + +### I.1 Fire detection case + +The IoT node through the sensor connection and/or the building management system (BMS) detects the ignition of a smoke sensor and verifies if it is a false alarm. The IoT node adds relevant context information to the alert event, for example, occupation of the building, arrangement of exits, prioritization of areas that are expected to be incorporated into the fire event, local action resources such as sprinkler system or fire extinguisher arrangement, etc.; and sends the message to the platform. This message activates the corresponding alert event to the platform of the authority/ person/system with responsibility or possibility to intervene. The platform processes the initial context of information provided by the IoT node and enriches it with data external to the building such as the location of nearby fire stations, traffic lights in the area, availability of water intakes, etc. This enrichment is oriented to the application of the automatic intervention protocol. The platform manages the automatic activation of the plan or, failing that, the request for action to the responsible or authorized persons. + +### I.2 Pollution + +The IoT node records the air pollution information by connecting to the sensors located on the street and on the roof and enriches it with context information such as positioning, temperature, moisture or other interest values, and sends this information to the city platform. With this information, the city generates a pollution forecast and modifies the behaviour of the city, by, for example, closing or diverting the traffic in some areas, keeping pollution at safe levels for citizens and issuing safety alerts that can inform the citizens about the situations and risks. + +### I.3 Water losses + +The IoT node obtains information regarding the water supply to the building and its consumption including the number of litres of water consumed and other vital information such as, water pressure and water pollution levels. The IoT nodes enriches this data with context data such as building positioning, number of tenants, type of use of the facilities, etc., and sends this information to the platform. The platform receives this information of the buildings of the city located in different distribution areas and analyses the consumption and supply. If it detects water leaks or dangerous pollution levels in any area, it informs the supplier companies of the incident and communicates with the IoT nodes of buildings to limit or close the water supply to the building, thus fostering the water management at a city level. + +### I.4 Earthquakes + +In case of seismic movements, the buildings are the most affected elements of the city. Consequently, the ability to make a real-time review of their conditions is very significant to minimizing the risks. In this context, the IoT node integrated with the city platform represents a great advantage when it comes to organizing and coordinating rescue services. The IoT node would receive the information from the different sensors of the building (inclinometers, crack meters, MEMS, accelerometers, etc.), process it and if structural problems are detected in the building, this situation is notified to the platform of the city. Additional information such as, the location, number of people that are in the building, access points, etc., could also be provided. The platform generates an evacuation plan according to the status of the different buildings, sending the emergency services to the most affected points of the city, evacuation zones or cutting the traffic of vehicles and people towards the dangerous zones. Simultaneously, the IoT node enables the security mechanisms of the building, activating + +alarms, escape zones, closing the gas and electricity supplies or activating fire control systems. On the other hand, the IoT node communicates its status to the nearby buildings and with this information, these buildings can make decisions such as to disable evacuation zones, or to close windows and shutters to minimize material and human losses in case of collapse of nearby buildings. + +## Bibliography + +- [b-ITU-T Y.101] Recommendation ITU-T Y.101 (2000), *Global Information Infrastructure terminology: Terms and definitions.* +- [b-ITU-T Y.3600] Recommendation ITU-T Y.3600 (2015), *Big data – Cloud computing based requirements and capabilities.* +- [b-ITU-T Y.4000] Recommendation ITU-T Y.4000/Y.2060 (2012), *Overview of the Internet of things.* +- [b-ITU-T Y.4552] Recommendation ITU-T Y.4552/Y.2078 (2016), *Application support models of the Internet of things.* +- [b-ITU-T Y.4900] Recommendation ITU-T Y.4900/L.1600 (2016), *Overview of key performance indicators in smart sustainable cities.* +- [b-ITU-T Y.4903] Recommendation ITU-T Y.4903/L.1603 (2016), *Key performance indicators for smart sustainable cities to assess the achievement of sustainable development goals.* +- [b-EU 2016/679] European General Data Protection Regulation 2016/679 + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information 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+CONSTRUCTION, INSTALLATION AND PROTECTION +OF CABLES AND OTHER ELEMENTS OF OUTSIDE +PLANT + +Energy efficiency, smart energy and green data centres + +--- + +**Smart energy solutions for city and home +applications** + +Recommendation ITU-T L.1383 + +# ITU-T L-SERIES RECOMMENDATIONS + +## ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT + +| | | +|---------------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node elements (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000–L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200–L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300–L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400–L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500–L.1599 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700–L.1799 | + +For further details, please refer to the list of ITU-T Recommendations. + +## Recommendation ITU-T L.1383 + +## Smart energy solutions for city and home applications + +## Summary + +Recommendation ITU-T L.1383 focuses on smart energy solutions in different application scenarios facilitating energy saving and carbon emission reduction. Besides their application in the field of ICT, such as in base stations, data centres and telecom centres, smart energy solutions have been applied in cities and homes as an advanced update to ICTs. Cities play a different role in different parts of the world. With the development of smart energy technologies, it is becoming possible to answer key issues in cities worldwide, prompted by the urgent necessity of GHG emissions reduction. + +This Recommendation includes specific smart energy applications in cities and homes, such as energy sources and energy management functions. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.1383 | 2021-10-07 | 5 | 11.1002/1000/14719 | + +### Keywords + +Cities, home, photovoltaic, renewable energy, smart energy, wind. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2021 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 2 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 2 | +| 6 Smart energy application for cities ..... | 2 | +| 6.1 Smart energy applications in business districts ..... | 2 | +| 6.2 Smart energy applications in residential communities..... | 4 | +| 6.3 Smart energy applications in industrial parks ..... | 4 | +| 6.4 Smart energy applications in electric transportation networks..... | 5 | +| 6.5 Smart energy applications in municipal areas ..... | 6 | +| 7 Smart energy applications in the home..... | 6 | +| 7.1 Multi-input multioutput power system at home ..... | 6 | +| 7.2 Smart energy facility at home..... | 7 | +| Bibliography..... | 9 | + + + +## Recommendation ITU-T L.1383 + +## Smart energy solutions for city and home applications + +## 1 Scope + +This Recommendation provides smart energy solutions that boost energy efficiency and reduce carbon emissions in different cities and home applications, namely: + +- City applications, including those in the business district, community, industrial park, transportation network and municipal area. +- Home applications including household appliances, electric vehicle charging, power dual-way trading and habit training of energy use. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T L.1220] Recommendation ITU-T L.1220 (2017), *Innovative energy storage technology for stationary use – Part 1: Overview of energy storage*. +- [ITU-T L.1221] Recommendation ITU-T L.1221 (2018), *Innovative energy storage technology for stationary use – Part 2: Battery*. +- [ITU-T L.1305] Recommendation ITU-T L.1305 (2019), *Data centre infrastructure management system based on big data and artificial intelligence technology*. +- [ITU-T L.1380] Recommendation ITU-T L.1380 (2019), *Smart energy solution for telecom sites*. +- [ITU-T L.1381] Recommendation ITU-T L.1381 (2020), *Smart energy solutions for data centres*. +- [ITU-T L.1382] Recommendation ITU-T L.1382 (2020), *Smart energy solutions for telecommunication rooms*. + +## 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 reliability** [b-ITU-T L.1022]: Probability that a product functions as required under given conditions, including maintenance, for a given duration without failure. + +NOTE 1 – The intended function(s) and given conditions are described in the user instructions provided with the product. + +NOTE 2 – Duration can be expressed in units appropriate to the part or product concerned, e.g., calendar time, operating cycles, distance run, etc., and the units should always be clearly stated. + +**3.1.2 smart energy** [ITU-T L.1380]: A power system that uses a smart control technique system to autonomously combine various energy supplies according to the working conditions of power supply and load. + +### **3.2 Terms defined in this Recommendation** + +This Recommendation defines the following terms: + +**3.2.1 business district:** A kind of area that is mainly composed of office buildings, malls, restaurants, etc. + +**3.2.2 electric transportation network:** A kind of network system that is composed of electric public transportation (bus, taxi, subway), electric private transportation and auxiliary infrastructure (charging station, charging pile, battery changing devices, etc.) + +**3.2.3 industrial park:** A kind of area that is mainly composed of different kinds of factories (such as gasoline manufacturing, cement manufacturing, fabric manufacturing and iron mine manufacturing factories). + +**3.2.4 municipal area:** A kind of area that is mainly composed of governmental buildings (such as energy administration, ministry of finance). + +**3.2.5 residential community:** A kind of area that is mainly composed of residences, parks, hospitals, supermarkets, schools, etc. + +## **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +GHG Greenhouse Gas + +ICT Information and Communication Technology + +## **5 Conventions** + +None. + +## **6 Smart energy application for cities** + +In some cases, the level of energy efficiency of city applications cannot be further optimized due to a lack of Information and Communication Technology (ICT). Therefore, it is crucial that cities take a proactive stance in improving the uptake of ICTs. They are key enablers for driving smart energy solutions in city applications. By facilitating the adoption of clean energy, regional customization, network communication and the Internet of Things, energy utilities in urban areas can be improved and optimized. Smart energy solutions can also promote conversion to all kinds of renewable energy sources such as solar, wind power, electric power and chemical power, increase the uptake of clean energy for electric power generation, optimize energy feeding structure and improve overall energy efficiency. Distinguished by their specific functions, smart energy solutions can be applied to five key domains of a city, including the business district, community, industrial park, electric transportation network and municipal area. + +### **6.1 Smart energy applications in business districts** + +Buildings in a business district consume high volume of energy owing to their complexities and high number of layers. Smart energy applications can improve the energy performance of such buildings by facilitating real-time monitoring and converting energy data into energy-saving functions. + +Figure 1 shows a smart energy system in an office building in a business district. By facilitating network interconnection using smart energy solutions such as big data technology and smart sensors, + +real-time and past data of energy consumption can be collected. Once the necessary data has been collected, smart control of an energy utility can then carry out analysis for optimization. The results can apply to each component according to their specific need. For example, a smart system can recognize energy waste in a specific room and automatically execute a remote power-off function to save energy. Meanwhile, a photovoltaic module can also be applied to the surface of buildings to power them with renewable energy, easing the reliance on the traditional grid. + +![A 3D cutaway diagram of a modern business building illustrating various smart energy and facility management systems. The building has multiple floors with people working inside. External systems include: HVAC maintenance services, Fire detection and alarm, Security and access control, Digital video, Intrusion detection, Environmental control, Asset locator, Mechanical maintenance and retrofit, Enterprise systems integration, On-site technical service, Lighting control and retrofit, Smoke control, Indoor air quality services, Energy supply and load management, Water management, and Energy information management. The diagram uses icons to represent each system and lines to connect them to the building's structure.](acfc53eca625d62b38aa2563efa95c3e_img.jpg) + +Detailed description of Figure 1: The diagram shows a multi-story glass-walled office building in a cutaway view. Various facility management and smart energy systems are labeled with lines pointing to specific areas of the building or its infrastructure. On the left side, labels include: Security and access control (with a card reader icon), Fire detection and alarm (with a flame icon), Digital video (with a camera icon), Intrusion detection, Environmental control (with a radiation/hazard icon), Asset locator (with a clock/gauge icon), and Mechanical maintenance and retrofit. At the top, HVAC maintenance services is labeled. On the right side, labels include: Lighting control and retrofit, Smoke control, Indoor air quality services, Energy supply and load management (pointing to an electrical pylon), Water management, and Energy information management (with a clock/gauge icon). At the bottom center, Enterprise systems integration and On-site technical service are labeled. The interior of the building shows office spaces with desks and people. + +A 3D cutaway diagram of a modern business building illustrating various smart energy and facility management systems. The building has multiple floors with people working inside. External systems include: HVAC maintenance services, Fire detection and alarm, Security and access control, Digital video, Intrusion detection, Environmental control, Asset locator, Mechanical maintenance and retrofit, Enterprise systems integration, On-site technical service, Lighting control and retrofit, Smoke control, Indoor air quality services, Energy supply and load management, Water management, and Energy information management. The diagram uses icons to represent each system and lines to connect them to the building's structure. + +L.1383(21) + +**Figure 1 – Smart Energy in a Business Building (the elements shown are applicable to buildings in business districts such as offices and malls)** + +In addition, power reliability is also important owing to the high density of people in the business district. The workload of operation and maintenance for relevant staff is high. After application of smart energy, potential reliability problems can be figured out in time and emerging reliability problems can be automatically solved. For instance, it is common that a large number of electric devices with different voltage levels, such as $220V_{ac}$ , $230V_{ac}$ , $380V_{ac}$ , $400V_{ac}$ , $48V_{dc}$ and $12V_{dc}$ , exist within a single office building. In such a case, the power distribution system would be prone to overload due to the various voltage levels and large number of devices. Under traditional operation and maintenance, the maintenance staff would need to check all power supply and utility devices layer by layer, which is a time consuming process, and it could be difficult to identify the point of failure in an emergency. With smart energy solutions, each power device can be automatically monitored and can perform self-check and self-solving in a very short space of time. With the support of big data analysis and AI technology, if there are potential problems, the relevant information can be sent to maintenance staff through a remote control application, so they can eliminate the potential problem by applying different smart solutions. + +### 6.2 Smart energy applications in residential communities + +Communities are an important part of cities. With renewable energy continuing to advance at a fast pace, solar and wind power are gradually being more commonly used for power generation. Meanwhile, power storage systems can be used to stabilize the fluctuation of power generation. The structure of a smart energy system in a residential community is shown in Figure 2. + +Different time slots entail different levels of energy consumption. For example, the level of energy consumption is relatively low in the morning in comparison with the evening. With smart energy solutions, the input power from wind turbine and photovoltaic modules can be stored in a battery system for future use (see [ITU-T L.1220] and [ITU-T L.1221] for details). In the case of critical infrastructure, such as hospitals, schools and supermarkets, smart energy systems can automatically adjust the proportion of output power based on energy demand [b-Mengdi Wang]. At night-time, the stored wind and solar electric power can be dynamically used based on real-time data of power need. At the same time, the connected electric vehicle charging piles can carry out dual-way power trading. On one side, an electric vehicle low in power can get lower-cost electricity and on the other side, an electric vehicle battery with higher capacity can feed power to the grid to sell energy. + +![Figure 2: Smart energy application in residential community. The diagram illustrates a power distribution system. At the top, a 'Battery' and a 'Super capacitor' are connected to a 'Power management system' via AC/DC converters. Below the power management system, a 'Load' and a 'Grid' are connected via transformers. At the bottom, a 'Solar/wind power generation system' is connected to the grid via DC/AC converters. An 'EV group' containing nine 'E-Car' icons is connected to the grid via a DC/AC converter. The entire system is enclosed in a dashed box labeled 'L.1383(21)'.](e6df2733626a85205c1db682e6259c46_img.jpg) + +The diagram shows a smart energy system architecture. At the top, a 'Battery' and a 'Super capacitor' are connected to a central 'Power management system' through AC/DC converters. Below the power management system, a 'Load' and a 'Grid' are connected via transformers. At the bottom, a 'Solar/wind power generation system' is connected to the grid through DC/AC converters. An 'EV group' containing nine 'E-Car' icons is connected to the grid via a DC/AC converter. The entire system is enclosed in a dashed box labeled 'L.1383(21)'. + +Figure 2: Smart energy application in residential community. The diagram illustrates a power distribution system. At the top, a 'Battery' and a 'Super capacitor' are connected to a 'Power management system' via AC/DC converters. Below the power management system, a 'Load' and a 'Grid' are connected via transformers. At the bottom, a 'Solar/wind power generation system' is connected to the grid via DC/AC converters. An 'EV group' containing nine 'E-Car' icons is connected to the grid via a DC/AC converter. The entire system is enclosed in a dashed box labeled 'L.1383(21)'. + +Figure 2 – Smart energy application in residential community (EV – electric vehicle) + +### 6.3 Smart energy applications in industrial parks + +In the case of industrial parks, smart energy solutions can help build a comprehensive energy utilizing system, as shown in Figure 3. Combined with traditional energy systems, a smart management system can improve the uptake of photovoltaic energy, wind energy and other clean energies. A smart controlling system is constructed to unify the management of energy and carry out analysis and prediction that would help to improve the utilization rate of regional energy and reduce the overall energy consumption of industrial parks. + +![A 3D architectural rendering of an industrial park showing various buildings, energy storage units, and infrastructure. The buildings are numbered 1 through 11, with labels for 'Technical research building', 'Dorm', 'Parking and charging', 'PV aisle', 'Distribution PV', '110 kV power transfer station', 'Factory', and 'Distributed energy storage'. The image is labeled L.1383(21) in the bottom right corner.](967c30813761a8952ecc5e16bf42ea45_img.jpg) + +A 3D architectural rendering of an industrial park showing various buildings, energy storage units, and infrastructure. The buildings are numbered 1 through 11, with labels for 'Technical research building', 'Dorm', 'Parking and charging', 'PV aisle', 'Distribution PV', '110 kV power transfer station', 'Factory', and 'Distributed energy storage'. The image is labeled L.1383(21) in the bottom right corner. + +L.1383(21) + +NOTE – The buildings numbered 1–11 are factories. + +**Figure 3 – Distributed energy in the industrial park** + +Power supply quality and reliability can be improved through the smart energy management system. Data collection and analysis on energy consumption could be achieved by leveraging artificial intelligence and big data technologies. Energy consumption can also be dramatically reduced using smart energy controlling strategies for the data centre as discussed in [ITU-T L.1305] and [b-Qi Shuguang]. Meanwhile, based on the grid price difference in different time periods, the "peak-cutting and valley-filling" method cited from [ITU-T L.1380] can also be applied to reduce the cost of power consumption and improve power supply security in the industrial park. + +Due to the massive volume of power consumption in the manufacturing process, it is common that a massive amount of heat would be emitted in parallel. With smart energy applications, heat can be recycled and reused for heating. In addition, by using a smart factory platform, high temperature heat can be recycled and reused as a mechanical power input to support the manufacturing process in factories. As a result, the volume of purchased electricity and CO2 emission would both be reduced. + +### 6.4 Smart energy applications in electric transportation networks + +Smart energy in transportation consists largely of electric vehicles and auxiliary devices such as charging piles. With the application of smart energy, the mode of charging and discharging of electric vehicles will be in a dual-way directional order. There are three types of scenarios in the dual-way mode of charging and discharging: + +- In-order charging: When a charging pile is plugged into an electric vehicle, charging work does not begin straight away. The power from a charging pile should be dispatched according to information (such as the residual volume of power or parking time) of users. +- Power demand management: ICT technology, power technology and electricity price data are integrated through smart energy management. + +- Electric vehicle charging and discharging in the microgrid: Distributed solar power and energy storage system are commonly found in the parkside microgrid. Through charging and discharging work from an electric vehicle, the above energy source can be connected to the grid by public busbar. Finally, the proportion of clear power provided by a renewable energy source can be increased. + +In some cities, there are many public charging stations for electric vehicles with different scales near office buildings. Smart energy application can unify the management of all electric vehicles and relevant infrastructure (charging pile, etc.), make the in-order charging and discharging rules, and facilitate the interconnection with the grid to stabilize the fluctuation of power generating. The basic concept of interconnection between electric vehicles and the power grid can be found in [b-Dmitry Baimel]. + +### 6.5 Smart energy applications in municipal areas + +Reliable and uninterrupted power supply is at the core of energy use in municipal areas along with energy saving and energy cleanliness. There is a high volume of important, and often confidential, national data transmitted and processed through administration application platforms. There would be detrimental consequences in case of power supply failure. Smart energy application can perform in-time safety prediction based on substantial situational data from the energy utility to minimize the possibility of power supply failure. By connecting with smart sensors of different kinds of power and energy devices, all operation data can be collected and analysed; therefore, any potential safety problem can be identified and relevant solutions will be provided through AI technology. Even in the case of extremely urgent situations, reliability problems can be automatically dealt with, and problem that are diagnosed can be quickly addressed. + +When inevitable problems occur in the energy system, a smart energy solution can quickly and effectively isolate the problematic section and resolve the problem. + +## 7 Smart energy applications in the home + +With the continuous improvement of living standards, various new types of household appliances have more functions and need a greater power supply, increasing the home energy consumption but providing greater convenience. Smart energy solutions at home can reduce energy consumption, promote energy efficiency, widen the proportion of new energy usage on power generation and create new habits related to power consumption. The purpose of smart energy design at home is making devices smart and energy-saving. Different kinds of sensors can collect energy data, and through ICT techniques such as big data and cloud computing, smart energy management system can control different parts of home powering in real time, such as setting the home lighting system and temperature control system to achieve more comfort and save energy. + +### 7.1 Multi-input multioutput power system at home + +With the greater adoption of solid-state electronics, solar photovoltaic power sources, other renewable energy systems and energy storage systems that supply DC power, there is increasing potential for DC-based generation, distribution, storage and utilization equipment. The specific property of this kind of hybrid solution can be illustrated through [ITU-T L.1381] and [ITU-T L.1382]. + +In some places, many rural houses have a roof photovoltaic module, battery, electric vehicle or even a small wind turbine. Different power generation sources can be integrated by a smart energy system, and it can make the power supply dynamic and optimistic considering the weather, volume of power, load rate, the sort of load and people's habits. In fact, it increases the proportion of power from renewable energy sources and indirectly reduces the carbon dioxide emission. + +This has given rise to an interest in the concept of DC microgrids, which are systems comprised of DC loads and distributed energy resources that can operate independently upon loss of the normal + +AC supply. Aside from the resiliency benefits of DC microgrids, DC power distribution can provide efficiency gains since multiple AC/DC conversions are avoided. The benefits of DC microgrids include increased resiliency and safety and improved performance, efficiency and stability, as well as plug-and-play capabilities. Furthermore, DC infrastructure can play a major part in "smart grid" power distribution, along with a decentralized power grid and digitization. The basic structure is shown in Figure 4. + +![Diagram of a DC Microgrid in the Home. A central DC bus is connected to various components. On the left, a VFD (Variable Frequency Drive) is connected to a fan icon. Below the VFD, a light bulb, a computer, and an electric car are connected to the DC bus via DC converters. A DC storage unit (battery) is also connected to the DC bus. On the right, a solar panel (DC) and a wind turbine (AC/DC) are connected to the DC bus. The entire system is enclosed in a dashed yellow box labeled 'DC bus'. An AC grid is connected to the DC bus via an AC/DC converter. The diagram is labeled 'L.1383(21)' in the bottom right corner.](4e4be0bd8b235167902f2c03e41da651_img.jpg) + +Diagram of a DC Microgrid in the Home. A central DC bus is connected to various components. On the left, a VFD (Variable Frequency Drive) is connected to a fan icon. Below the VFD, a light bulb, a computer, and an electric car are connected to the DC bus via DC converters. A DC storage unit (battery) is also connected to the DC bus. On the right, a solar panel (DC) and a wind turbine (AC/DC) are connected to the DC bus. The entire system is enclosed in a dashed yellow box labeled 'DC bus'. An AC grid is connected to the DC bus via an AC/DC converter. The diagram is labeled 'L.1383(21)' in the bottom right corner. + +**Figure 4 – DC Microgrid in the Home (VFD – variable frequency drive)** + +Meanwhile, self-generated-and-utilized energy can be powered by photovoltaic and wind power [b-Shujun Liu]. If the amount of residual power is too great to be stored, it is convenient to trade the excess power in the energy market. In another way, smart energy application in the home can effectively train a new type of power utilizing habit. By applying smart energy solutions, a new ecosystem, in which energy efficiency becomes integrated into the core of energy systems at home, could be established. + +### 7.2 Smart energy facility at home + +Objects in the home are becoming smarter than before. By applying smart energy solutions, electric and electronic household appliances can be unified in an energy management application. Users can obtain real-time power consumption data, which provides clear information on the power consumption of each device (see Figure 5). Through expert guidance, energy waste and its precise location can be discerned. Thus, new habits of power usage can be promoted, and unnecessary consumption avoided [b-Hongbin Sun]. + +## Data summary + +![](0b8b087a7baa471015d3ffeaa43d9a6c_img.jpg) + +| Voltage | | | Current | | | Temperature | | | +|-----------------|----------------|-----|-----------------|----------------|-----|---------------------|--------------------|------| +| Highest voltage | Lowest voltage | | Highest current | Lowest current | | Highest temperature | Lowest temperature | | +| 238 V | 210 V | (V) | 100 A | 20 A | (A) | 40 °C | 10 °C | (°F) | + +### Historical alarm summary day + +![Bar chart showing the number of alarms for various types over a day. The y-axis is 'Number of alarms' from 0 to 30. The x-axis lists alarm types: Short circuit, surge, Overload, Overtemperature, Leakage, Overcurrent, Overvoltage, Phase missing, Fire, Undervoltage.](0332672e127cd13bb6d2fc8d1e27bfa2_img.jpg) + +| Alarm Type | Number of Alarms | +|-----------------|------------------| +| Short circuit | 20 | +| surge | 25 | +| Overload | 20 | +| Overtemperature | 30 | +| Leakage | 10 | +| Overcurrent | 15 | +| Overvoltage | 18 | +| Phase missing | 22 | +| Fire | 26 | +| Undervoltage | 30 | + +Bar chart showing the number of alarms for various types over a day. The y-axis is 'Number of alarms' from 0 to 30. The x-axis lists alarm types: Short circuit, surge, Overload, Overtemperature, Leakage, Overcurrent, Overvoltage, Phase missing, Fire, Undervoltage. + +### Percentage of alarms + +![Donut chart showing the percentage distribution of alarm types. A callout indicates Overtemperature at 14%.](bafe3c344aef7f6f79dab49c9eca89a9_img.jpg) + +| Alarm Type | Percentage | +|-----------------|------------| +| Short circuit | ~10% | +| Surge | ~12% | +| Overload | ~8% | +| Overtemperature | 14% | +| Leakage | ~5% | +| Overcurrent | ~7% | +| Overvoltage | ~6% | +| Phase missing | ~9% | +| Fire | ~11% | +| Undervoltage | ~18% | + +Donut chart showing the percentage distribution of alarm types. A callout indicates Overtemperature at 14%. + +L.1383(21) + +**Figure 5 – Energy management application** + +Aside from their basic function, some current home smart energy solutions also integrate an energy generation and storage function. This additional function helps users to cut energy bills by using solar power during the most expensive peak hours, and selling excess power back to the grid in off-peak hours. + +## Bibliography + +- [b-Dmitry Baimel] Dmitry Baimel, Saad Tapuchi, Nina Baimel. *Smart Grid Communication Technologies*[J]. Journal of Power and Energy Engineering,2016,4(8):1-8. +- [b-Hongbin Sun] Hongbin Sun, et al. (2020), *Energy Internet*[M].Science Press:Beijing, China: 357-357. +- [b-Mengdi Wang] Mengdi Wang (2020), *Study of Smart Energy Application and Evaluation System*. +- [b-Qi Shuguang] *Study and application on data center infrastructure management system based on AI and big data technology* (2019), IEEE 4th International Future Energy Electronics Conference (IFEEC). +- [b-Shujun Liu] Shujun Liu. *Study of Application of Power Station with Voltage of 660V*[D] (2013), Beijing: North China Electric Power University. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | 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communication technology goods, networks and services** + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue circular emblem with a stylized globe and the letters 'ITU' in white. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +## **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|--------------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| Infrastructure including node elements (except cables) | L.200-L.249 | +| General aspects and network design | L.250-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| Optical fibre cable maintenance | L.300-L.329 | +| Infrastructure maintenance | L.330-L.349 | +| Operation support and infrastructure management | L.350-L.379 | +| Disaster management | L.380-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1410 + +# Methodology for environmental life cycle assessments of information and communication technology goods, networks and services + +## Summary + +Recommendation ITU-T L.1410 deals with environmental life cycle assessments (LCAs) of information and communication technology (ICT) goods, networks and services. It is organized in two parts: + +- Part I: ICT life cycle assessment: framework and guidance. +- Part II: Comparative analysis between ICT and reference product system (baseline scenario); framework and guidance. + +Part I deals with the life cycle assessment (LCA) methodology applied to ICT goods, networks and services. Part II deals with comparative analysis based on LCA results of an ICT goods, networks and services product system, and a reference product system. + +## History\* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.1410 | 2012-03-08 | 5 | 11.1002/1000/11430 | +| 2.0 | ITU-T L.1410 | 2014-12-07 | 5 | 11.1002/1000/12207 | +| 3.0 | ITU-T L.1410 | 2024-11-06 | 5 | 11.1002/1000/16010 | + +## Keywords + +Comparative analysis, energy consumption, environment, goods, greenhouse gas emissions, information and communication technologies (ICTs), life cycle assessment (LCA), networks, services. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, and information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2025 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|------|-----------------------------------------------------------------------------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 2 | +| 3 | Definitions ..... | 2 | +| 3.1 | Terms defined elsewhere ..... | 2 | +| 3.2 | Terms defined in this Recommendation ..... | 4 | +| 4 | Abbreviations and acronyms ..... | 8 | +| | Part I – ICT life cycle assessment: framework and guidance ..... | 12 | +| 5 | Conventions ..... | 12 | +| 6 | General description ..... | 12 | +| 6.1 | General description of an LCA..... | 12 | +| 6.2 | Compliance to this Recommendation..... | 13 | +| 6.3 | Comparisons of results ..... | 14 | +| 6.4 | Relationship between methodologies of LCAs for ICT goods, networks
and services ..... | 14 | +| 7 | Methodological framework ..... | 15 | +| 7.1 | General requirements..... | 15 | +| 7.2 | Goal and scope definition ..... | 19 | +| 7.3 | Life cycle inventory (LCI)..... | 39 | +| 8 | Life cycle impact assessment (LCIA)..... | 47 | +| 8.1 | Introduction to LCIA ..... | 47 | +| 8.2 | Impact categories..... | 47 | +| 9 | Life cycle interpretation..... | 50 | +| 9.1 | General ..... | 50 | +| 9.2 | Uncertainty analysis ..... | 51 | +| 9.3 | Sensitivity analysis ..... | 51 | +| 10 | Reporting ..... | 51 | +| 10.1 | General ..... | 51 | +| 10.2 | ICT goods ..... | 52 | +| 10.3 | ICT network..... | 56 | +| 10.4 | ICT services..... | 59 | +| 11 | Critical review ..... | 63 | +| | Part II – Comparative analysis/LCA between ICT and reference product systems (baseline
scenario): framework and guidance ..... | 64 | +| 12 | General description of comparative analysis ..... | 64 | +| 12.1 | Need for comparative analysis ..... | 64 | +| 12.2 | Target systems for comparative analysis..... | 65 | +| 12.3 | Principles of comparisons between systems (comparative analysis) ..... | 66 | + +| | Page | +|--------------------------------------------------------------------------------------------------------------|------| +| 12.4 Procedures of comparisons between systems (comparative analysis) ..... | 67 | +| 13 Methodological framework of comparative analysis ..... | 67 | +| 13.1 General requirements..... | 67 | +| 13.2 Goal and scope definition ..... | 67 | +| 13.3 Life cycle inventory..... | 69 | +| 13.4 Life cycle impact assessment ..... | 69 | +| 13.5 Life cycle interpretation ..... | 69 | +| 14 Reporting ..... | 70 | +| 15 Critical review ..... | 71 | +| Annex A – Details regarding the handling of software ..... | 72 | +| Annex B – Modelling of unit processes..... | 74 | +| Annex C – Support activities ..... | 76 | +| Annex D – Generic processes ..... | 77 | +| Annex E – Part types of ICT goods ..... | 79 | +| Annex F – EoLT processes ..... | 83 | +| Annex G – Elementary flows (emissions and resources) ..... | 84 | +| Annex H – List of raw materials..... | 89 | +| Annex J – ICT network overview ..... | 91 | +| Annex K – A method for assessing the environmental load of the working environment ..... | 93 | +| K.1 Purpose of targeting the working environment in the assessment of ICT goods, networks and services ..... | 93 | +| K.2 Functional unit..... | 93 | +| K.3 System boundary ..... | 93 | +| K.4 Life cycle inventory (LCI)..... | 94 | +| Annex L – Reporting formats ..... | 95 | +| Appendix I – Void..... | 104 | +| Appendix II – Life cycle stages overview ..... | 105 | +| Appendix III – Examples of goods and black box modules ..... | 106 | +| III.1 End-user goods ..... | 106 | +| III.2 CPE..... | 106 | +| III.3 Network site goods (from base station sites to data centres)..... | 106 | +| III.4 Examples of ICT-specific black box modules..... | 107 | +| III.5 Site support goods ..... | 107 | +| Appendix IV – Examples of networks and network goods ..... | 108 | +| Appendix V – Energy mix ..... | 110 | +| Appendix VI – Examples of Allocation Procedures ..... | 111 | +| VI.1 Allocation examples for Recycling of Materials ..... | 111 | +| Appendix VII – Example of data quality indicators ..... | 114 | + +| | | +|---------------------------------------------------------------------------------------------------------------------------|-----| +| Appendix VIII – Uncertainties of life cycle assessments for ICT goods, networks and services ..... | 115 | +| Appendix IX – Opportunities and limitations in the use of LCAs for ICT goods, networks and services..... | 117 | +| Appendix X – Examples for calculating second order effects..... | 119 | +| X.1    Consumption of goods (paper, CDs, DVDs, etc.) ..... | 119 | +| X.2    Power consumption/energy consumption (electricity, gasoline, kerosene, light oil, heavy oil, town gas, etc.) ..... | 119 | +| X.3    Movement of people (car, bus, railroad, aircraft, etc.) ..... | 119 | +| X.4    Movement and storage of goods (mail, truck, railroad cargo, air cargo, cargo ship, etc.)..... | 120 | +| X.5    Improved work efficiency (electricity, office area, etc.) ..... | 120 | +| X.6    Waste (wastepaper, garbage, plastic, industrial waste, etc.) ..... | 121 | +| Appendix XI – GWP values 100-year time frame ..... | 122 | +| Appendix XII – Summary of requirements..... | 123 | +| Appendix XIII – The relation between LCA and Circular Economy for ICT ..... | 143 | +| Appendix XIV – Application scenarios for LCA of ICT goods with extended operating lifetime and multiple life cycles ..... | 144 | +| XIV.1  LCA covering cradle-to-grave of a ICT goods with extended operating lifetime..... | 144 | +| XIV.2  LCA of first life cycle of ICT goods with multiple life cycles ..... | 144 | +| XIV.3  LCA of second life cycle of a ICT goods with multiple life cycles ..... | 145 | +| XIV.4  Comparative LCA of a ICT goods with extended operating lifetime ..... | 145 | +| Appendix XV – Example analysis of different refurbishment configurations ..... | 146 | +| Bibliography..... | 148 | + +## Introduction + +This Recommendation has been developed to complement [ISO 14040] and [ISO 14044] for the environmental assessment of the life cycle impact of information and communication technology (ICT) goods, networks and services. + +The present document was developed jointly by ETSI TC EE and ITU-T Study Group 5. It was published respectively by ITU as Recommendation ITU-T L.1410 and ETSI Standard [b-ETSI ES 203 199], which are equivalent in technical content. + +This document defines a set of requirements to reflect the quality that LCA practitioners should strive for. At this stage, some of the requirements put forward here are considered challenging due to LCA tool limitations, lack of data, limitations in data granularity, etc. It is thus recognized that compliance to all requirements in this Recommendation may not be possible at the time of publication. However, to foster the transparency of LCA results and for the quality of data and life cycle assessment (LCA) tools to improve over time, this Recommendation defines certain requirements which are outlined in the following pages. The Recommendation requires that deviation(s) from the requirements be clearly motivated and reported. For further details regarding compliance refer to clause 6.2. + +The development of information and communication technologies (ICTs) has led to concerns regarding their environmental impact. Taking into consideration the ongoing efforts within the United Nations Framework Convention on Climate Change [b-UNFCCC] to combat climate change, ITU-T and ETSI decided to enhance their previous work by jointly developing an internationally agreed methodology to help the ICT sector assess the environmental impact of ICT goods, networks and services. This Recommendation also gives guidance on the assessment of software. + +Unlike many products and services sold in the world today, ICT distinguishes itself by its double-edged nature. On the one hand, ICTs have an environmental impact at each stage of their life cycle, e.g., from energy and natural resource consumption to e-waste. On the other hand, ICTs can enable vast efficiencies in lifestyle and in all sectors of the economy through the provision of digital solutions that can improve energy efficiency, inventory management, and business efficiency by reducing travel and transportation, e.g., teleworking and videoconferencing and by substituting physical products for digital information, e.g., e-commerce. + +Different levels of impact are acknowledged in some academic literature as the three-order effects of ICTs: + +- First-order effects (or the environmental load of ICTs): the impacts created by the physical existence of ICTs and the processes involved, e.g., energy consumption and greenhouse gas (GHG) emissions, e-waste, use of hazardous substances and use of scarce, non-renewable resources. +- Second-order effects (or the environmental load reduction achieved by ICTs): the impacts and opportunities created by the use and application of ICTs. This includes environmental load reduction effects which can be either actual or potential, such as travel substitution, transportation optimization, working environment changes, use of environmental control systems, use of e-business, e-government, etc. +- Higher-order effects: + - particularly for some ICT services such as teleworking or videoconferencing, the time gained by an end user using an ICT service may cause additional impact e.g., a leisurely drive and economic activities, which are difficult to track. Such additional impacts are often defined as "rebound effects". + +Most of the benefits of ICTs lie in the second-order effects via increased efficiency, transparency, speed of transactions, rapid market-clearing, long-tail effects and so on. There are environmental + +impacts associated with the first order: environmental impact of ICT goods, networks and services such as resource consumption and carbon emissions during manufacturing and the disposal of hardware. This Recommendation focuses on the first and second-order effects. [b-ITU-T L.1480] provides further guidance on the second-order effects and higher-order effects, as well as the impacts and opportunities created by the aggregated effects on societal structural changes by using ICTs. + +In constructing a sustainable society from an environmental viewpoint, the negative aspects of ICTs should be minimized, and the positive ones should be maximized, as summarized in Figure 1. + +![Figure 1: Schematic model for the environmental assessment of ICT goods, networks and services. The diagram features two identical scales. The left scale has a pink platform labeled 'Environmental load caused by ICT'. To its left, a red downward arrow points to a dashed line, with text 'Minimization towards environmentally sustainable ICT sector' and a red upward arrow. The right scale has a green platform labeled 'Environmental load reduction achieved by ICT'. To its right, a green upward arrow points to a dashed line, with text 'Maximization towards environmentally sustainable society' and a green downward arrow. Below the left scale is a box titled 'Negative aspects on environment' containing: '- Consumption of energy', '- Consumption of natural resources', and '- Generation of waste'. Below the right scale is a box titled 'Positive aspects on environment' containing: '- Dematerialization (digitization of information)', '- Reduction of movement and transportation', and '- Making industry and lifestyles more efficient etc.'. At the bottom center, a box with a right-pointing arrow contains the text 'Should quantify both environmental aspects'. The code 'L.1410(12)_F01' is in the bottom right corner.](562f471e8153729557e6a4ee6343c32c_img.jpg) + +Figure 1: Schematic model for the environmental assessment of ICT goods, networks and services. The diagram features two identical scales. The left scale has a pink platform labeled 'Environmental load caused by ICT'. To its left, a red downward arrow points to a dashed line, with text 'Minimization towards environmentally sustainable ICT sector' and a red upward arrow. The right scale has a green platform labeled 'Environmental load reduction achieved by ICT'. To its right, a green upward arrow points to a dashed line, with text 'Maximization towards environmentally sustainable society' and a green downward arrow. Below the left scale is a box titled 'Negative aspects on environment' containing: '- Consumption of energy', '- Consumption of natural resources', and '- Generation of waste'. Below the right scale is a box titled 'Positive aspects on environment' containing: '- Dematerialization (digitization of information)', '- Reduction of movement and transportation', and '- Making industry and lifestyles more efficient etc.'. At the bottom center, a box with a right-pointing arrow contains the text 'Should quantify both environmental aspects'. The code 'L.1410(12)\_F01' is in the bottom right corner. + +**Figure 1 – Schematic model for the environmental assessment of ICT goods, networks and services** + +The first-order effect (or environmental load caused by ICT) can be quantified by performing a life cycle assessment (LCA). The second-order effect (or environmental load reduction achieved by ICT) can be quantified by the comparison of LCA results between the ICT goods, networks and services product system and the reference product system performing the same function. + +To reflect the first two-order effects, this Recommendation describes environmental assessments through a life cycle assessment (LCA) which is a systematic analytical method and model by which the potential environmental effects related to ICT goods, networks and services can be estimated. This Recommendation also gives guidance on the assessment of software. LCAs have a cradle-to-grave scope where the life cycle stages, i.e., *raw material acquisition, production, use, and end-of-life* are included. Moreover, transport and energy supplies are included at each life-cycle stage. + +ISO has standardized the LCA methodology. In this document, ICT-specific additions to the [ISO 14040] and [ISO 14044] standards will be described. In addition to the [ISO 14040] and [ISO 14044] standards, the European Commission has published a handbook that gives detailed guidance on all the steps required to conduct an LCA [b-EUR 24708 EN]. This handbook will also be referred to with special ICT considerations in mind. + +The standard is divided into two parts: + +- Part I (clauses 6-11) – ICT life cycle assessment: framework and guidance. This part deals with the LCA methodology applied to ICT goods, networks and services. +- Part II (clauses 12-15) – Comparative analysis between an ICT product system and a reference product system (baseline scenario): framework and guidance. This part deals with comparative analysis based on LCA results of the ICT goods, networks and services product system and the reference product system. + +The structure of this LCA methodology specification for ICT goods, networks and services is shown in Figure 2. The figure indicates where specific requirements and considerations apply for ICT goods, networks and services respectively, and where the same requirements and considerations apply for all of those product systems. + +![Figure 2: Structure of LCA methodology specification for ICT goods, networks and services. The diagram shows a flow of seven vertical boxes representing LCA stages. The first four stages (General requirements, Goal and scope definition, Life cycle inventory (LCI), and Life cycle impact assessment (LCIA)) are grouped by a dashed box on the left, indicating they apply to all product systems. The fifth stage (Life cycle interpretation) is a single box. The sixth stage (Comparative assertion between ICT and non-ICT services) is grouped by a dashed box on the right, indicating it applies specifically to ICT services. The seventh stage (Reporting) is grouped by a dashed box on the right and has three sub-categories: Services, Network, and Equipment, each in its own dashed box.](cfda9df1319e04207eb28bcefd1dab7b_img.jpg) + +L.1410(14)\_F02 + +Figure 2: Structure of LCA methodology specification for ICT goods, networks and services. The diagram shows a flow of seven vertical boxes representing LCA stages. The first four stages (General requirements, Goal and scope definition, Life cycle inventory (LCI), and Life cycle impact assessment (LCIA)) are grouped by a dashed box on the left, indicating they apply to all product systems. The fifth stage (Life cycle interpretation) is a single box. The sixth stage (Comparative assertion between ICT and non-ICT services) is grouped by a dashed box on the right, indicating it applies specifically to ICT services. The seventh stage (Reporting) is grouped by a dashed box on the right and has three sub-categories: Services, Network, and Equipment, each in its own dashed box. + +**Figure 2 – Structure of LCA methodology specification for ICT goods, networks and services** + +The structure of Part I and Part II is based on [ISO 14040] and [ISO 14044] in order to support the LCA practitioner, and thus each part is structured in accordance with: + +- General requirements: high level requirements of assessment. +- Goal and scope definition: requirements of the functional unit, system boundaries and data quality. +- Life cycle inventory (LCI): requirements for data collection, calculation and allocation. +- Life cycle impact assessment (LCIA): requirements for impact assessment. +- Life cycle interpretation: requirements for the interpretation of results and calculation of second order effects. +- Reporting: requirements for reporting. + +Both parts are then divided into applicable subclauses, and Part I is additionally structured into the three product system types, i.e., ICT goods, networks and services, as appropriate. + +This Recommendation is intended for LCA practitioners who want to assess the impact of ICT goods, networks and services, and it will help them to perform and report their LCAs of *ICT goods, networks and services* in a uniform and transparent manner. It is possible to use this document to get guidance on what to consider in an LCA on three levels: ICT goods, networks and services. + +The following uses of ICT LCA applications are the most frequent ones, but others may be identified as well: + +- evaluation of product systems' environmental impact, such as climate change; +- assessment of primary energy consumption; +- identification of life-cycle stages and activities which are of great significance; + +- comparisons of specific ICT goods, networks or services under the conditions described in clause 6.3; +- comparative analysis between an ICT product system and a reference product system. + +NOTE – The LCA practitioner is advised to check ITU-T Recommendations giving guidance on simplified LCA methods, when relevant. + + + +# **Recommendation ITU-T L.1410** + +## **Methodology for environmental life cycle assessments of information and communication technology goods, networks and services** + +## **1 Scope** + +This Recommendation aims to provide a methodology for evaluating the environmental impact of ICTs objectively and transparently and is based upon the life cycle assessment (LCA) methodology standardized in [ISO 14040] and [ISO 14044]. + +This Recommendation can be read by anyone aiming for a better understanding of the specific conditions and requirements applicable to the LCA of ICT goods, networks and services. However, this Recommendation is especially intended for LCA practitioners with a prior knowledge of LCA standards, i.e., [ISO 14040] and [ISO 14044]. + +The purpose of this Recommendation is to: + +- provide ICT-specific requirements, in addition to those of [ISO 14040] and [ISO 14044], to ensure a sufficient quality of LCA studies of ICT goods, networks and services; increase the quality of the LCA by adding ICT-specific requirements to those of [ISO 14040] and [ISO 14044]; +- harmonize the LCAs of ICT goods, networks and services; +- increase the credibility of LCAs of ICT goods, networks and services; +- increase the transparency, and facilitate the interpretation of LCA studies of ICT goods, networks and services; +- facilitate the communication of LCA studies of ICT goods, networks and services; and +- provide a methodology for telecommunication operators and service providers to assess the environmental load of one or more services carried by their ICT networks. + +While recognizing [ISO 14040] and [ISO 14044], including Annex A of [ISO 14040] "Application of LCA", as normative references, this document will give generic and specific requirements for the LCA of ICT goods, networks and services. This Recommendation is valid for all types of ICT goods including end-user goods, and also for ICT networks and services. This document also gives guidance on the assessment of software. LCA practitioners are encouraged to also consider other environmental aspects in accordance with [ISO 14040] and [ISO 14044]. + +This Recommendation defines a set of requirements which reflect the quality that LCA practitioners should strive for. At this stage some of the requirements put forward here are considered as challenging due to LCA tool limitations, a lack of data, limitations in data granularity, etc. It is thus recognized that compliance to all requirements in this Recommendation may not be possible at the time of publication. However, to foster results of LCAs becoming more transparent, and for the quality of data and LCA tools to improve over time, this document defines the requirements outlined in the following pages. This Recommendation requires that deviation(s) from the requirements are clearly motivated and reported. For further details regarding compliance refer to clause 6.2. + +Comparisons of results from environmental assessments of ICT goods, networks and services, which have been performed by different organizations, are beyond the scope of this Recommendation, as such comparisons would require that the assumptions and context of each study are equivalent. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ISO 14040] ISO 14040:2006, *Environmental management – Life cycle assessment – Principles and framework*. + +[ISO 14044] ISO 14044:2006, *Environmental management – Life cycle assessment – Requirements and guidelines*. + +## 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 activity data** [b-GHG Protocol CVCS]: A quantitative measure of a level of activity that results in GHG emissions. + +**3.1.2 CO2 equivalent (CO2e)** [b-GHG Protocol CS]: The universal unit of measurement to indicate the global warming potential (GWP) of each of the seven greenhouse gases, expressed in terms of the GWP of one unit of carbon dioxide. It is used to evaluate releasing (or avoiding releasing) different greenhouse gases against a common basis. + +**3.1.3 comparative assertion** [ISO 14040]: Environmental claim regarding the superiority or equivalence of one product versus a competing product that performs the same function. + +**3.1.4 cradle-to-gate** [b-ETSI ES 203 199]: Partial life cycle of ICT goods or parts, from material acquisition through to when they leave the factory gate (e.g., immediately following the production). + +NOTE 1 – This definition has been amended from GHG Protocol Product Standard. + +NOTE 2 – E.g., ICT goods ready to be put on the market/sales with no need for further processing. + +**3.1.5 customer-premises equipment (CPE)** [b-ETSI ES 203 199]: Any terminal and associated information and communication technology (ICT) goods located at a subscriber's premises and connected with a carrier's telecommunication channel(s) at the network termination points (NTPs). + +NOTE – Customer-premises equipment (CPE) also covers home office goods. + +**3.1.6 emission factor** [b-GHG Protocol CS]: A factor allowing GHG emissions to be estimated from a unit of available activity data (e.g., tonnes of fuel consumed, tonnes of product produced) and absolute GHG emissions. + +NOTE – Another example is: kgCO2e/kWh electricity, kgCO2e/(tonne×km). + +**3.1.7 extended operating lifetime** [b-ETSI ES 203 199]: Aggregated duration of the actual use periods of the first life cycle and possible consecutive life cycles. + +NOTE 1 – The user in different life cycles can be the same or different user. + +NOTE 2 – Circular processes, such as reuse and refurbishment, enable several use periods and consecutive life cycles. + +NOTE 3 – This definition is aligned with [b-CLC TR 45550]. + +**3.1.8 functional unit** [ISO 14040]: Quantified performance of a product system for use as a reference unit. + +**3.1.9 greenhouse gases (GHGs)** [b-GHG Protocol CS]: For the purposes of this methodology, GHGs are the seven gases listed in the Kyoto Protocol: + +- carbon dioxide (CO2) +- methane (CH4) +- nitrous oxide (N2O) +- hydrofluorocarbons (HFCs) +- perfluorocarbons (PFCs) +- sulphur hexafluoride (SF6) +- nitrogen trifluoride (NF3). + +**3.1.10 higher order effect** [b-ITU-T L.1480]: The indirect effect (including but not limited to rebound effects) other than first and second order effects occurring through changes in consumption patterns, lifestyles and value systems. + +NOTE 1 – Rebound effects include effects occurring through financial gains, savings in time and space, and others. + +NOTE 2 – Higher order effects could be associated with both second and first order effects. + +**3.1.11 life cycle** [ISO 14040]: Consecutive and interlinked stages of a product system, from raw material acquisition or generation from natural resources to final disposal. + +**3.1.12 maintenance** [b-ITU-T L.1022]: Action carried out to retain a product in a condition where it is able to function as required. + +NOTE – Examples of such actions include inspection, adjustments, cleaning, lubrication, testing, software update and replacement of a wear-out part. Such actions could be performed by users in accordance with instructions provided with the equipment (e.g., replacement or recharging of batteries); or the actions could be performed by service personnel in order to ensure that parts with a known time to failure are replaced in order to keep the product functioning. + +**3.1.13 primary data** [b-ISO 14046]: Quantified value of a unit process or an activity obtained from a direct measurement or a calculation based on direct measurements at its original source. + +NOTE 1 – In practice, primary data may be emission factors and/or activity data. + +NOTE 2 – Primary data includes site-specific data, i.e., data from one specific unit process within a site; and site-average data, i.e., representative averages of site-specific data collected from organizations within the product system which operate equivalent processes. + +**3.1.14 product system** [ISO 14040]: Collection of unit processes with elementary and product flows, performing one or more defined functions, and which models the life cycle of a product. + +**3.1.15 raw material** [ISO 14040]: Primary or secondary material that is used to produce a product. + +**3.1.16 refurbishment** [b-ITU-T L.1023]: Industrial process which produces a product from used products without any changes influencing safety, original performance, purpose or type of the product. + +NOTE – New and/or used parts can be used during refurbishment. + +**3.1.17 repair** [b-ITU-T L.1022]: Process of returning a faulty product to a condition where it can fulfil its intended use. + +**3.1.18 second order effect** [b-ITU-T L.1480]: The indirect impact created by the use and application of ICTs which includes changes of environmental load due to the use of ICTs that could be positive or negative. + +NOTE – Second order effects can be either actual or potential. + +**3.1.19 secondary data** [b-ISO 14046]: Data obtained from sources other than a direct measurement or a calculation based on direct measurements at the original source. + +NOTE – Such sources can include databases (a list of LCA databases (publicly available and licence based) provided by the EU, published literature, national inventories, and other generic sources. + +**3.1.20 waste** [ISO 14040]: Substances or objects which the holder intends or is required to dispose of. + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 active area:** An area of the display or touch panel which is useful for touching or viewing. + +**3.2.2 black box module:** A device, system or object which can be viewed solely in terms of its input, output and transfer characteristics without any knowledge of its internal workings. + +NOTE – In this context the black box module may consist of several part categories such as integrated circuits, mechanics, cables etc., e.g., a power module on a printed circuit board assembly (PCBA). + +**3.2.3 commercial lifetime:** The length of time that a good is owned for before a new one is bought to replace it. + +NOTE – Commercial lifetime is often used to estimate the lifetime for consumer products. + +**3.2.4 comparative analysis:** Analysis aiming to compare two different product systems based on the same functional unit. + +**3.2.5 cut-off:** Amount of energy or material flow, or the level of environmental significance associated with unit processes or product systems excluded from the study. + +NOTE – Unit processes excluded from the studied product system in a life cycle assessment (LCA). + +**3.2.6 data gap:** Life cycle inventory (LCI) flows excluded from a unit process within the studied product system. + +**3.2.7 depreciation time:** Time during which a (new) revenue-generating asset reaches its residual economic value. + +NOTE – The depreciation time is sometimes referred to as the legal lifetime. + +**3.2.8 economic input-output approach (EIO):** Method using tables, called input-output (IO) tables, that describe financial transactions between economic sectors in a national economy, to approximate environmental impacts. + +**3.2.9 embodied emissions:** The lifecycle(s) greenhouse gas (GHG) emissions from the following life cycle stages: raw material acquisition, production and end-of-life treatment. + +NOTE 1 – Each life cycle includes transportation as generic process. + +NOTE 2 – The greenhouse gas (GHG) emissions include all life cycle stages other than the use stage. + +**3.2.10 embodied environmental impact:** The life cycle(s) environmental impact from the following life cycle stages: raw material acquisition, production and end-of-life treatment. + +NOTE 1 – Each life cycle includes transportation as generic process. + +NOTE 2 – The life cycle(s) include all life cycle stages other than the use stage. + +**3.2.11 end-user goods:** Any device that can connect to customer-premises equipment (CPE) or networks. + +EXAMPLE – Laptop, mobile phone. + +**3.2.12 environmental impact:** Overall assessment of the positive and negative aspects on the environment. + +**3.2.13 environmental impact through the introduction of information and communication technologies:** The difference between the environmental load reduction effect from the use of information and communication technologies (ICTs) and the environmental load of ICTs. + +**3.2.14 environmental load:** Environmental aspect which potentially causes interference with environmental conservation. + +**3.2.15 environmental load of information and communication technologies:** The environmental impact of information and communication technologies (ICTs) throughout their entire life cycle, including the processes of raw material acquisition, production, use, and end-of-life treatment, covering ICT goods, networks, and services. + +**3.2.16 environmental load reduction effect from using information and communication technologies:** The effect that noticeably reduces the environmental load of solutions and services using information and communication technologies (ICTs). + +NOTE – The effects of "improving energy efficiency", "improving the efficiency of and reducing the production and consumption of goods", and "reducing the movement of people and goods" are brought about by using ICTs. + +**3.2.17 first order effect:** Direct environmental effect associated with the physical existence of an information and communication technology (ICT) solution, i.e., the raw materials acquisition, production, use and end-of-life treatment stages, and generic processes supporting those including the use of energy and transportation. + +NOTE 1 – First order effects include environmental impacts, e.g., greenhouse gas (GHG) and other emissions, e-waste, use of hazardous substances and use of scarce, non-renewable resources. + +NOTE 2 – First order effects are sometimes referred to as environmental footprints. + +**3.2.18 generic operating system:** Commercially available software that handles the basic hardware operations such as memory allocation, handling of processes and disk access, as well as the user interface. + +**3.2.19 global warming potential (GWP):** Ratio of the warming of the atmosphere caused by one greenhouse gas to that caused by a similar mass of carbon dioxide. + +**3.2.20 greenhouse gas emission intensity:** The numerical value of greenhouse gas (GHG) emissions per unit. + +**3.2.21 hybrid life cycle assessment:** Method that combines the approach of process-sum and economic input-output life cycle assessments (LCAs). + +NOTE – Different models exist, prioritizing data from either process-sum or input-output data. + +**3.2.22 information and communication technology goods:** Tangible goods deriving from or making use of technologies devoted to or concerned with: + +- the acquisition, storage, manipulation (including transformation), management, movement, control, display, switching, interchange, transmission or reception of a diversity of data; +- the development and use of the hardware, software, and procedures associated with this delivery; and +- the representation, transfer, interpretation, and processing of data among persons, places, and machines, noting that the meaning assigned to the data is preserved during these operations. + +NOTE – According to the definition given in [b-ETSI TS 103 199], the word "equipment" is used instead. + +**3.2.23 information and communication technology manufacturer:** Organization which has the financial and organizational control of the design and production of information and communication technology goods. + +**3.2.24 information and communication technology network:** Set of nodes and links that provide physical or over the air information and communication connections between two or more defined points. + +EXAMPLE – Wireless network, fixed network, local area network (LAN), home network and server network, access networks, core networks, cloud computing networks. + +**3.2.25 information and communication technology service including applications:** Use of information and communication technology (ICT) goods and/or networks to provide value to one or more users. + +EXAMPLE – Teleconferencing, teleworking, e-ticketing, e-learning, e-healthcare, smart transport and logistics, procurement systems, supply chain management systems, music/film distribution over the Internet or voice over IP, machine-to-machine systems. + +**3.2.26 information and communication technology-specific data:** Data emerging from information and communication technology (ICT)-specific applications and processes. + +NOTE – This data could be either primary or secondary. + +**3.2.27 information and communication technology specific end-of-life treatment:** Any disassembly/dismantling/shredding/recycling process which needs special adaptation for handling of information and communication technology (ICT) goods. + +**3.2.28 information and communication technology-specific infrastructure:** Basic structures needed for the operation of the goods, network or service. + +EXAMPLE – Antenna towers, cabling systems. + +**3.2.29 infrastructure:** Basic structures needed for the operation of the society. + +EXAMPLE – Transportation systems, buildings and power plants. + +**3.2.30 land use:** Human exploitation of land for agricultural, industrial, residential and recreational purposes. + +**3.2.31 life cycle assessment practitioner:** Person(s) or organization(s) performing a life cycle assessment (LCA). + +**3.2.32 life cycle stage:** One of several consecutive and interlinked stages of a product system. + +**3.2.33 lifetime:** A duration which may correspond to commercial aspects, operating aspects – possibly extended – or for example, depreciation. + +**3.2.34 modelled data:** Assumption-driven estimates, such as estimates resulting from scenarios, which are forward looking or scaled up from smaller pilot studies. + +**3.2.35 natural resource:** Material source that occurs in a natural state. + +NOTE – A natural resource can be e.g., wood, water, or a mineral deposit. + +**3.2.36 network termination point (NTP):** Point established in a building or complex to separate customer premises equipment (CPE) from telephone company goods. + +**3.2.37 node:** Point in a network topology at which lines intersect or branch. + +**3.2.38 operating lifetime:** Duration of the actual use period (consisting of both active and non-active periods) for the first user. + +NOTE – Storage time is not included in operating lifetime. + +**3.2.39 optional activity:** Unit process which can be left out of the life cycle assessment (LCA) because of low significance, low precision, general lack of data or other practical reasons. + +**3.2.40 organizational data:** Data that describe central characteristics of organizations, their internal structures and processes as well as their behaviour as corporate actors in different social and economic contexts. + +**3.2.41 other end-of-life treatment:** Any disassembly, dismantling, shredding or recycling process which does not need special adaptation for handling of information and communication technology goods but could be used for any kind of good. + +**3.2.42 part:** Constituent of information and communication technology (ICT) goods and support goods. + +EXAMPLE – Cable. + +**3.2.43 part category:** The classification of a part e.g., by its type. + +EXAMPLE – Fibre cable. + +**3.2.44 potential environmental load reduction effect:** The potential environmental load reduction which is expected due to the progress of information and communication technologies (ICTs) throughout society, but which is not expected to take place immediately. + +**3.2.45 primary energy:** The energy content of natural resources which can be used for energy production. + +**3.2.46 primary raw material:** Material which originates from natural resources. + +**3.2.47 process category:** The classification of a process type. + +EXAMPLE – Landfill, air, ship and train. + +**3.2.48 processed materials:** Raw materials which have been physically and/or chemically changed by humans. + +**3.2.49 process-sum approach:** Method using facility-level data describing processes in terms of the inputs of materials and energy, outputs of products and waste, and emissions. + +**3.2.50 public data:** Data which is available to the public without access being restricted by requirements on membership, none-disclosure agreements, or similar restrictions. + +**3.2.51 ratio of recycled raw material content:** Amount of recycled raw material in relation to the amount of primary raw material used as the input to production. + +**3.2.52 raw material extraction:** Production of extracted raw materials used in raw material processing. + +**3.2.53 raw material processing:** Production of processed raw materials used in the production of a part. + +**3.2.54 raw material recycling:** Production of raw materials from recycled products. + +**3.2.55 recommended activity:** Unit process potentially significant to the result and which should be included in the life cycle assessment (LCA). + +**3.2.56 recycling rate of disposed raw material:** The rate at which disposed goods end up in a recycling process as part of the scope of the life cycle assessment (LCA). + +**3.2.57 reference product system:** System (basically non-ICT but can also be information and communication technology (ICT)) which is replaced by ICT. + +EXAMPLE – Traditional service which is replaced by an ICT service. + +**3.2.58 reuse:** Process by which a product or its parts, having reached the end of their first use, are used for the same purpose for which they were conceived. + +NOTE 1 – Reuse after second or subsequent usage is also considered as reuse, but normal, regular or sporadic use is not considered as reuse. + +NOTE 2 – Information and communication technology (ICT) goods usage by a new user or in a new context is considered to be reuse. + +NOTE 3 – Definition amended from [b-ETSI EN 303 808] with additional Note 2. + +**3.2.59 secondary raw material:** Material that originates from recycled primary raw materials. + +**3.2.60 service provider:** Organization operating a service. + +**3.2.61 storage time:** Length of time for which the goods are stored, including the time before and the time after they are used. + +**3.2.62 support activity:** Activities supporting unit processes associated with the function of the good, network or service. + +NOTE – Examples of support activities are activities directly associated with the product system, such as marketing, development and sales and also more general activities of the organization, such as data support, communication, and financial support. + +**3.2.63 support goods:** A device, system or object needed to realize the function of supporting the use of information and communication technology (ICT) goods. + +EXAMPLE – Goods for power supply and temperature regulation. + +NOTE – See standard [b-ETSI TS 202 336-1] for an explanation which defines support goods for networks as infrastructure goods. + +**3.2.64 telecommunication/datacentre operator:** Organization operating networks and services. + +NOTE – Examples of operators are enterprise realizing and managing private network, traditional telecommunications operator realizing and managing public network, companies working in end user market, information and communication technology (ICT) and good manufactures. + +**3.2.65 the 0/100 method:** Allocation method that allocates 0% of the primary raw material acquisition processes to the studied product system. + +**3.2.66 the 50/50 method:** Allocation method that allocates the credits equally to the life cycle using and the one supplying recycled material. + +**3.2.67 the 100/0 method:** Allocation method that allocates the primary raw material acquisition processes fully to the studied product system. + +NOTE – No recycling is assumed to occur at end-of-life. + +**3.2.68 traffic:** Total volume of cells, blocks, frames, packets, calls, messages or other units of data carried over a circuit or network, or processed through a switch, router or other system. + +**3.2.69 unit process:** Smallest element considered in the life cycle inventory analysis for which input and output data are quantified. + +EXAMPLE – Part unit process such as integrated circuit (IC) encapsulation and display module assembly. + +NOTE – See also [ISO 14040] and [ISO 14044]. + +## 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|------------------------------------| +| 3G | Third generation telecom networks | +| 4G | Fourth generation telecom networks | +| ABS | Acrylonitrile Butadiene Styrene | +| AC/DC | Alternating Current Direct Current | +| BAT | Best Available Technology | +| BGA | Ball Grid Array | +| BOD | Biochemical Oxygen Demand | +| BOM | Bill of Materials | + +| | | +|------------------|--------------------------------------------| +| BS | Base Station | +| BSC | Base Station Control Site | +| BTS | Base Transceiver Station | +| C&C | Command and Control | +| CAS | Chemical Abstracts Service | +| CATV | Cable Access Television | +| CC | Climate Change | +| CD | Compact Disc | +| CED | Cumulative Energy Demand | +| CFC | Chlorofluorocarbons | +| CO | Carbon monoxide | +| CO 2 | Carbon dioxide | +| CO 2e | Carbon dioxide equivalent | +| COD | Chemical Oxygen Demand | +| CPE | Customer-Premises Equipment | +| DALY | Disability Adjusted Life Years | +| DSL | Digital Subscriber Line | +| DSLAM | Digital Subscriber Line Access Multiplexer | +| DVD | Digital Versatile Disc | +| EA | Eutrophication Aquatic | +| EHW | Environmentally Hazardous Waste | +| EI | Environmental Impact | +| EIICT | Environmental impact of ICT | +| EIO | Economic Input-Output | +| EOL | End-of-life | +| EoLT | End-of-life Treatment | +| EPC | Evolved Packet Core | +| ET | Eutrophication Terrestrial | +| ETFW | Ecotoxicity Freshwater | +| FWT | Fixed Wireless Terminal | +| GB | Gigabyte | +| GGSN | Gateway GPRS Support Node | +| GHG | Greenhouse Gas | +| GNS | Goods, Networks and Services | +| GPRS | General Packet Radio Service | +| GPS | Global Positioning System | +| GSM | Global System for Mobile communications | + +| | | +|---------|------------------------------------------------| +| GWP | Global Warming Potential | +| HD | High Density | +| HFC | Hydrofluorocarbons | +| HLR | Home Location Record | +| HT | Human Toxicity | +| HTC | Human Toxicity Cancer effects | +| HTNC | Human Toxicity Non-Cancer effects | +| HW | Hardware | +| IC | Integrated Circuit | +| ICT | Information and Communication Technology | +| ICT GNS | ICT Goods, Networks and Services | +| ILCD | International reference Life Cycle Data system | +| IP | Internet Protocol | +| IPCC | Intergovernmental Panel on Climate Change | +| IPTV | Internet Protocol Television | +| IRE | Ionizing Radiation Ecosystems | +| IRH | Ionizing Radiation Human health | +| LAN | Local Area Network | +| LCA | Life Cycle Assessment | +| LCD | Liquid Crystal Display | +| LCI | Life Cycle Inventory | +| LCIA | Life Cycle Impact Assessment | +| LD | Low Density | +| LED | Light Emitting Devices | +| LNG | Liquefied Natural Gas | +| LPG | Liquefied Petroleum Gas | +| LTE | Long Term Evolution | +| LU | Land Use | +| MGW | Media Gateway | +| MJ | Megajoule | +| MUX | Multiplexer | +| NMHC | Non-Methane Hydrocarbons | +| NMVOC | Non-Methane Volatile Organic Compounds | +| NOX | Nitrogen Oxides | +| O&M | Operation and Maintenance | +| OD | Ozone Depletion | +| ODP | Ozone Depletion Potential Indicator | + +| | | +|-------|-------------------------------------------| +| OLED | Organic Light Emitting Diodes | +| OLT | Optical Line Terminal | +| ONU | Optical Network Unit | +| PA | Polyamide | +| PAH | Polycyclic Aromatic Hydrocarbon | +| PBA | Printed Board Assembly | +| PBX | Private Branch Exchange | +| PCB | Printed Circuit Boards | +| PCBA | Printed Circuit Board Assembly | +| PDH | Plesiochronous Digital Hierarchy | +| PDP | Plasma Display Panel | +| PE | Polyethylene | +| PEF | Product Environmental Footprint | +| PET | Polyethylene Terephthalate | +| PMMA | Polymethyl Methacrylate | +| POF | Photochemical Ozone Formation | +| PP | Polypropylene | +| PS | Polystyrene | +| PTFE | Polytetrafluoroethylene | +| PUR | Polyurethane | +| PVC | Polyvinyl Chloride | +| RAN | Radio Access Networks | +| RBS | Radio Base Station | +| RDMR | Resource Depletion Mineral Resources | +| RDW | Resource Depletion Water | +| RI/PM | Respiratory Inorganics/Particulate Matter | +| RMA | Raw Material Acquisition | +| RNC | Radio Network Controller | +| RSS | Remote Subscriber Switch | +| SAC | Sn/Ag/Cu alloys | +| SAN | Styrene Acrylonitrile | +| SDH | Synchronous Digital Hierarchy | +| SGSN | Serving GPRS Support Node | +| SOHO | Small Offices Home Offices | +| STB | Set-Top Box | +| STM | Synchronous Transport Module | +| TOE | Total Oil Equivalent | + +| | | +|--------|----------------------------------------| +| TV | Television | +| UE | User Equipment | +| UPS | Uninterruptible Power Supply | +| USGS | United States Geological Survey | +| UV-B | Ultraviolet B | +| VLR | Visitor Location Register | +| VOC | Volatile Organic Compounds | +| VoIP | Voice over Internet Protocol | +| W-CDMA | Wideband Code Division Multiple Access | +| WAN | Wide Area Network | +| WDM | Wavelength Division Multiplexer | +| WLAN | Wireless Local Area Network | + +# PART I + +## ICT life cycle assessment: framework and guidance + +## 5 Conventions + +This Recommendation contains requirements (denoted as mandatory or by the use of the word 'shall'), recommendations (denoted by the use of the word 'should'), and options (denoted as optional or by the use of the word 'may'). + +## 6 General description + +### 6.1 General description of an LCA + +An environmental life cycle assessment (LCA) is a systematic, analytical method by which the potential environmental effects related to ICT goods, networks and services (ICT GNS) can be estimated. LCAs have a cradle-to-grave scope, which includes all the life cycle stages (raw material acquisition, production, use, and end-of-life treatment). Moreover, transport and energy supplies are included at each stage of the life cycle assessment. + +LCAs became internationally standardized by the International Organization for Standardization (ISO) with the publication of the ISO 14040 series of life cycle assessment standards, representing an important step in consolidating procedures and methods of LCAs. + +ICT goods, networks, and services are associated with the environmental load that emerges from different processes over the life cycle. The environmental impact caused by this environmental load is sometimes referred to as first-order effects. + +By definition, an LCA considers the full life cycle, meaning that no life cycle stages should be excluded *a priori*. However, if a life cycle stage is found to have a limited impact on the results and conclusions of an LCA, the corresponding life cycle stage or items in the life cycle stage may be excluded in accordance with applicable rules for cut-off. + +This Recommendation shall also apply to studies that do not cover the full life cycle. In this case, please refer to clause A.1.2 in [ISO 14040]. + +ICT goods, networks and services have the potential to reduce the environmental load and impact by reducing the amount of energy consumption and materials used in society. This potential to reduce the environmental impact is referred to as second-order effects and is covered by Part II (clauses 12-15). Moreover, [b-ITU-T L.1480] provides further guidance on the second-order effects and higher-order effects, as well as the impacts and opportunities related to climate and created by the aggregated effects on societal structural changes of using ICTs. + +Often, the impact from second-order effects outweighs the first order effects, leading to a net positive environmental impact when systems of ICT goods, networks, and services are applied. + +The ISO LCA standards define four phases of an LCA study: + +- goal and scope definition +- life cycle inventory (LCI) +- life cycle impact assessment (LCIA) +- life cycle interpretation. + +To report the results of an LCA study, ISO also defines two additional steps – critical review and reporting, in addition to the phases mentioned. + +LCA is, by nature, an iterative technique, where each phase or step depends on the results or methodologies used in another (whether previous or subsequent) phase or step. For example, defining the studied product system is a step that directly impacts on the subsequent steps of boundary setting, data collection and allocation. When performing an LCA of ICT goods, networks and services, the eight checklist items specified in clause 7.2.3.5.2 should be considered in the system boundary setting to identify activities associated with the ICT goods, networks and services life cycle for which data will be collected. Other items may also exist. Figure 3 below shows the framework of Part I, which is based on Figure 1 of [ISO 14040]. + +![Figure 3 – Framework of Part I of this Recommendation. The diagram shows a flowchart of the LCA process. On the left, a box labeled 'Goal and scope definition' contains a 'Checklist items:' list: 1. ICT hardware, 2. ICT software, 3. Consumables and other supportive products, 4. Site infrastructure, 5. Office working environment (work processes), 6. Transport (movement of goods), 7. Travel (movement of people), 8. Storage of goods. Below this box is 'Inventory analysis', which is below 'Impact assessment'. Arrows show a downward flow from Goal and scope definition to Inventory analysis to Impact assessment. On the right, a large box labeled 'Interpretation' has arrows pointing to it from each of the three boxes. There are also feedback arrows from the Interpretation box back to each of the three boxes. The diagram is labeled 'L.1410(14)_F03' at the bottom right.](2734e7f9be3e1dc046f14be2e6c9a085_img.jpg) + +Figure 3 – Framework of Part I of this Recommendation. The diagram shows a flowchart of the LCA process. On the left, a box labeled 'Goal and scope definition' contains a 'Checklist items:' list: 1. ICT hardware, 2. ICT software, 3. Consumables and other supportive products, 4. Site infrastructure, 5. Office working environment (work processes), 6. Transport (movement of goods), 7. Travel (movement of people), 8. Storage of goods. Below this box is 'Inventory analysis', which is below 'Impact assessment'. Arrows show a downward flow from Goal and scope definition to Inventory analysis to Impact assessment. On the right, a large box labeled 'Interpretation' has arrows pointing to it from each of the three boxes. There are also feedback arrows from the Interpretation box back to each of the three boxes. The diagram is labeled 'L.1410(14)\_F03' at the bottom right. + +**Figure 3 – Framework of Part I of this Recommendation** + +### 6.2 Compliance to this Recommendation + +This Recommendation contains requirements, recommendations and options. For additional details on the terminology used to distinguish between them, refer to clause 5. + +Requirements are summarized in Appendix XII. + +In addition, this Recommendation contains numerous recommendations which also need consideration. + +Full compliance with this Recommendation can be claimed if all mandatory requirements are fulfilled. + +LCAs can also partially comply with this Recommendation by complying with the majority of mandatory 'shall' requirements; however, they are unable to fulfil all of them due to data gaps, a lack of transparency in databases, and so forth. + +In both cases the fundamental LCA principles of relevance, completeness, consistency, accuracy and transparency shall guide the LCA practitioner. + +As stated in the scope, clause 1, it is acknowledged that full compliance with this Recommendation may not be possible at this stage, especially at the network and service levels, where some data may be based on already published LCAs of ICT goods, which, especially initially, may not be in accordance with this Recommendation. + +The compliance statement contained in the report should disclose and explain any deviations from the requirements and the use of non-compliant data. + +### 6.3 Comparisons of results + +It is important to realise that comparisons of results (absolute and relative values) between LCAs are beyond the scope of this Recommendation, as such comparisons would require that the assumptions and context of each LCA are equivalent. + +LCAs can be performed and presented by different individuals/organizations or by the same individual/organization. However, comparisons of LCA results obtained by the same individual/organization who/which uses: + +- i) this Recommendation; +- ii) the same LCA tool; and +- iii) the same life cycle inventory (LCI) databases for all 'comparables' are supported by this Recommendation. A third-party review is also needed if the comparison result is to be externally communicated. + +In case of comparative assessment between ICT goods LCAs, the operating lifetime shall be set to equal. Differences in lifetime could only be accepted if they reflect differences in actual characteristics. + +### 6.4 Relationship between methodologies of LCAs for ICT goods, networks and services + +Figure 4 shows the product systems targeted by the impact assessment methodologies of ICT goods, ICT networks, and ICT services. In this context, ICT networks and ICT services can be seen as logical structures, which are physically made up of ICT goods, including hardware and software, but which also rely, for instance, on building premises, civil works to create cable ways, air conditioning, power generators and power storage such as an uninterruptible power supply (UPS). + +![A diagram showing three stacked boxes representing the relationship between ICT goods, networks, and services. The top box is labeled 'ICT services', the middle box is labeled 'ICT networks', and the bottom box is labeled 'ICT goods'. To the right of the bottom box is the text 'L.1410(14)_F04'.](e05c1a13b44ab41505609d82b00cf4df_img.jpg) + +| | +|--------------| +| ICT services | +| ICT networks | +| ICT goods | + +L.1410(14)\_F04 + +A diagram showing three stacked boxes representing the relationship between ICT goods, networks, and services. The top box is labeled 'ICT services', the middle box is labeled 'ICT networks', and the bottom box is labeled 'ICT goods'. To the right of the bottom box is the text 'L.1410(14)\_F04'. + +**Figure 4 – Relationship between ICT goods, networks and services** + +As ICT networks are composed of ICT goods and as ICT services utilize ICT networks, the methodology for ICT goods forms the basis for the methodologies for ICT networks and ICT services. In other words, the methodology for ICT networks is based on the methodology for ICT goods, and the methodology for ICT services accommodates both methodologies for ICT goods and networks. + +Consequently, the environmental impact assessment of ICT networks reflects the environmental impact of ICT goods employed in the ICT networks, and the environmental impact assessment of ICT services reflects the environmental impact assessments of ICT goods and ICT networks employed in the ICT services. + +ICT networks and ICT services are not physical entities but logical concepts which are built upon ICT goods. For this reason, it could be difficult to define their assessment boundaries in detail. Consequently, it is important that their boundaries do not overlap to avoid any double-counting effect when an ICT service is assessed with both ICT goods and networks. + +Due to the use of ICT goods, networks and services in projects, organizations, cities and countries, this Recommendation may form a basis for the environmental impact assessment methodologies for these assessment purposes. + +## **7 Methodological framework** + +### **7.1 General requirements** + +When performing an ICT-related LCA, the requirements of this Recommendation shall apply, as well as those of [ISO 14040] and [ISO 14044], i.e., all three standards have to be taken into account. + +#### **7.1.1 Life cycle stages** + +The following four high-level life cycle stages shall apply to ICT goods, networks, and services and shall be assessed as applicable in LCAs based on this Recommendation, in accordance with its goal and scope: + +- Goods raw material acquisition which is composed of: + - raw material extraction + - raw material processing. +- Production, which is composed of: + - ICT goods production (including refurbishment) + - support goods production. +- Use, which is composed of: + - ICT goods use + - support goods use + - operator support activities + - service provider support activities. +- Goods end-of-life treatment (EoLT), which is composed of: + - preparation for extended operating lifetime + - ICT-specific EoLT + - other EoLT. + +NOTE 1 – Production waste is allocated to the production stage; see clause 7.3.3.2. + +If all these life cycle stages have not been assessed, this should be stated when reporting. + +For guidance on software refer to clause 7.1.4. + +Impacts from transport and energy supplies shall be included in all life cycle stages. Deviation(s) from this requirement shall be clearly motivated and reported. + +NOTE 2 – The assessment of the raw material acquisition stage is generally based on secondary data from databases. At the time of publication, to collect appropriate data related to raw material transportation and to + +separate data related to the raw material acquisition stage and production stage is considered challenging due to LCA tool limitations, lack of data, limitations in data granularity and the nature of ICT supply chains. + +It is important that all transportation within and between life cycle stages are included in the assessment. For instance, the transportation of goods between production and use stages shall be taken into account. The data collected shall be structured in such a way that the greenhouse gas (GHG) emissions and energy consumption/environmental impact arising from the transportation processes could be reported transparently, as far as possible. + +It is optional to include the construction of plants in which ICT or support goods are manufactured. If the construction of factory is included in the assessment, the impact per product is to be calculated by following allocation rules in clause 7.3.3 and cut-off rules in clause 7.2.4 when applicable. + +Table 2 in clause 7.2.3.1 defines the detailed life cycle stages, which further define the system boundary and are to be considered when assessing the life cycle impact of ICT goods, networks, and services. In particular, it is important to cover all processes which are marked as mandatory in this table. + +The system boundaries outline the life cycle activities that are of relevance to define the life cycle of the ICT goods, networks and services to be assessed. Within these system boundaries, the cut-off rules according to clause 7.2.4 shall apply. This means that activities that are found negligible may be cut off, although they are within the system boundary. + +The study report should transparently show and justify whenever processes marked with 'mandatory' are not taken into account. + +Throughout the life cycle, some processes will reoccur several times, e.g., unit processes associated with the life cycle impact of electricity use, transport and travel. These processes are referred to as generic processes and are further described in Annex D. + +Also, Appendix II gives additional information on the different stages and on the interfaces between the processes. + +#### **7.1.2 ICT goods with multiple life cycles** + +ICT goods may experience different forms of extended lifetime, for example, through reuse or refurbishment. Products that are reused or refurbished will enter a new life cycle (as part of extended operating lifetime). At the end of product's use stage, a decision about product's future is made – whether it goes to reuse or refurbishing, or to waste processing. An assessment boundary shall be established at the point where the current life cycle ends and a new life cycle starts (second use). The environmental impact associated with the product that does not proceed to the next life is considered in waste management (EoLT) of the first (or current) life, and environmental impact associated with the refurbishment production process (making it fit for second use) is considered in production stage of the next life. + +#### **7.1.3 The goods, networks and services product system** + +The ICT goods, networks and services product system to be assessed shall be clearly described, as well as relevant functions and characteristics. + +##### **7.1.3.1 ICT goods** + +For the ICT good under study, applicable types of parts, as well as the amounts of these, shall be defined. + +In-depth information about the product composition is required before setting the system boundary of the product. Often, bill of materials (BOM) data (where parts information, including mass and material composition, is listed) is necessary to understand the full product composition. Table E.1 provides generic information about the composition of ICT goods. A process tree showing the interconnectivity among parts and various items in each life cycle of ICT goods can be developed + +using the product composition information. By arranging parts in descending order of mass and by calculating the cumulative mass of each part, a basis is given for a cut-off of insignificant parts from the product system. Note, however that other cut-off criteria shall apply as well. + +##### 7.1.3.2 ICT networks + +An ICT network is an ICT-based infrastructure which offers the possibility to transfer voice and/or data between different access points, usually referred to as nodes, and also further on to the end users (e.g., represented by a mobile phone or a PC). + +ICT networks are often grouped into fixed and wireless networks. Each ICT network consists of: + +- Customer premises (e.g., terminal, terminating goods, and protectors); +- Access network goods (e.g., telephone poles, conduits, changers, local switches, and base stations), and +- Core networks (e.g., routers and transmitters). + +Figure 5 below gives an example of the physical layer of a fixed network. + +![Figure 5 – Fixed telecommunication network – simplified physical view. The diagram illustrates the physical layer of a fixed network, divided into three main components: a) Customer premises, b) Access network equipment, and c) Core network. Component (a) includes 'Terminal equipment' (a computer) connected to a 'Terminating set', which is connected to a 'Protector'. Component (b) includes a 'Cable' running from the 'Protector' through a 'Telephone pole' and a 'Conduit'. Component (c) includes a 'Local modem' connected to the 'Conduit', which is then connected to a 'Router'. The 'Router' is part of a 'Core network' represented by a large oval containing a crossed line.](f0a97d0d3818a253c1d2a009966081b1_img.jpg) + +Figure 5 – Fixed telecommunication network – simplified physical view. The diagram illustrates the physical layer of a fixed network, divided into three main components: a) Customer premises, b) Access network equipment, and c) Core network. Component (a) includes 'Terminal equipment' (a computer) connected to a 'Terminating set', which is connected to a 'Protector'. Component (b) includes a 'Cable' running from the 'Protector' through a 'Telephone pole' and a 'Conduit'. Component (c) includes a 'Local modem' connected to the 'Conduit', which is then connected to a 'Router'. The 'Router' is part of a 'Core network' represented by a large oval containing a crossed line. + +L.1410(12)\_F05 + +**Figure 5 – Fixed telecommunication network – simplified physical view** + +Ultimately, the total network may be studied, taking into account both fixed and wireless networks and the connection between them. However, a study may also focus on just a part of the network. In the goal and scope phase, it shall be outlined which network building blocks are covered. + +For the ICT network under study, applicable types of nodes and infrastructure, as well as amounts of these, shall be defined. + +Annex J details the most frequently adopted ICT networks in use today. However, this Recommendation is not restricted to these networks but shall also apply when assessing any existing or future networks. + +Examples of how the functional unit, system boundaries and the data to be gathered may be defined are given in Appendix I. + +##### 7.1.3.3 ICT services + +For the ICT service under study, applicable types of ICT network elements and infrastructure, as well as the amounts of these, shall be defined. + +#### 7.1.4 Handling of software + +##### 7.1.4.1 General + +Software shall be considered, as well as hardware. + +Any ICT good, network or service consists of both hardware and software, which both impact, e.g., the production and use stages. Moreover, software may also be an assessment target in itself. For the production stage software development impacts on the number of people involved in the development work and thus impacts on the amount of buildings and travel associated with the development of the ICT good or network, in the same way as hardware development. For the use stage, the software impacts, e.g., maintenance and energy use. In general, it is not relevant to distinguish between software and hardware impact for the use stage but rather to focus on the impact from the ICT goods or network or service. + +For specific software applications, such as music distribution applications, the software is to be seen as an ICT service and shall be assessed according to the requirements outlined for services. In these cases, the hardware needed to operate the software shall be considered as well. This development is either within B1.3 or B1.1.11 (see Figure 9) depending on where the software is developed. + +Due to the uncertainties of allocation, it is optional to consider the embedded impact from use of generic operating systems and other widely spread software (e.g., simulation tools) when assessing the software impact. Also, the life cycle impact of this software may be considered negligible for the users of the operating systems. + +However, for the developer of this software the impact of the usage of this software shall be taken into account. + +##### 7.1.4.2 Assessment of software + +Many software products are used in ICT goods, networks and services. The software categories include, but are not limited to, operating systems, middleware (information system management, databases, etc.), application software (software for electronic applications, etc.) and software customized for specific users, according to the structure shown in Figure 6. + +![Figure 6: Software structure of an ICT system (example). The diagram shows a vertical stack of software layers. From top to bottom: 'Customized software', 'Application software', 'Middleware . . . Middleware', and 'Operating system (OS)'. The entire stack is enclosed in a rectangular box. Below the box, the text 'L.1410(14)_F06' is written.](6470d350326789d5306eabcb76533951_img.jpg) + +Figure 6: Software structure of an ICT system (example). The diagram shows a vertical stack of software layers. From top to bottom: 'Customized software', 'Application software', 'Middleware . . . Middleware', and 'Operating system (OS)'. The entire stack is enclosed in a rectangular box. Below the box, the text 'L.1410(14)\_F06' is written. + +Figure 6 – Software structure of an ICT system (example) + +A user, e.g., an operator, often designs or purchases customized software and also purchases other shared software. Table 1 goes further than Figure 6 and provides the corresponding allocation principles. + +Table 1 – Classification and allocation principles for ICT software + +| Type | Classification | Category | Allocation embedded of environmental impact | +|------|---------------------------------------------------------------|-------------------------------------------------------------------------|---------------------------------------------| +| 1 | Customized software developed specifically for or by the user | Customized software | 1 | +| 2 | Shared software developed for general purposes | Application software (e.g., system software for electronic application) | 1/L (see Note) | + +**Table 1 – Classification and allocation principles for ICT software** + +| Type | Classification | Category | Allocation embedded of environmental impact | +|------|----------------|-----------------------------------------------------------------------|---------------------------------------------| +| 3 | | Middleware (e.g., information system management, database and others) | 1/M (see Note) | +| 4 | | Operating system | 1/N (see Note) | + +NOTE – L = sales volume of Application software (e.g., system software for electronic application) +M = sales volume of Middleware +N = sales volume of Operating system. + +It is not necessary to report the sales volumes L, M and N. + +As stated in clause 7.1.4.1, generic operating systems should not be included in assessments performed by its user as the uncertainty of allocation is high. + +For details on assessment of software, refer to Annex A. + +#### 7.1.5 Operating lifetime + +Operating lifetime is critical for the interpretation of the results of LCAs and shall therefore always be reported when presenting LCA results. Operating lifetime estimates and assumptions shall also be clearly described in the reporting. + +Operating lifetime can only be defined for goods. In general, the lifetime of an ICT network cannot be defined as a network lifetime with one start date and one end date; instead the network is continuously built out, upgraded, etc. and the associated operating lifetimes are therefore the lifetimes of the individual nodes. The same is valid for ICT services. However, in some cases, temporary networks could be established for a limited amount of time. For such networks, an operating lifetime is applicable. + +Operating lifetime should be based on available information on actual goods use (e.g., statistics for similar goods, networks and services or information on commercial lifetime) and should model a real operating lifetime as closely as possible. If information on actual use of goods, networks and services cannot be found, economic statistics may be used to estimate the operating lifetime, e.g., depreciation time. However, such estimates are considered less accurate and should be avoided. + +NOTE – If the LCA is used to estimate a historical environmental impact, actual use time may be available and can then be used. In most cases, actual operating lifetime is not available, and estimates are needed. + +Storage time is not included in operating lifetime. + +When available, results for a known extended operating lifetime, taking into account also any reuse of directly reused or refurbished ICT goods should be reported together with any corresponding information about the first use. Extended operating lifetime is estimated according to the same principles as the (first) operating lifetime. + +### 7.2 Goal and scope definition + +#### 7.2.1 Goal and scope of the study + +In accordance with [ISO 14040], the goal of an LCA states: + +- The intended application; +- The reasons for carrying out the study; +- The intended audience, i.e., those to whom the results of the study are intended to be communicated; + +- Whether the results are intended to be used in comparative assertions intended to be disclosed to the public. + +During the LCA scoping phase, the building blocks of the ICT goods, networks or services shall be identified, including software. + +NOTE – These building blocks are preferably identified from functional block diagrams provided, e.g., by system engineers/architects. + +Schematically, three main levels of targeted product systems exist: + +- Goods (ICT goods and support goods) +- Networks (ICT network) +- Services (ICT service). + +In addition, software may be assessed according to clause 7.1.4. + +All these product systems use ICT goods, which follows the life cycle stages introduced in clause 7.1.1 and which are further described in this clause. + +Goods refer to the different physical products, with associated software, constituting the network. ICT and support goods consist of, e.g., electronic parts, mechanical parts, cooling parts, and cables. + +Printed circuit board assemblies (PCBA) and shelves are examples of included parts. The PCBAs consist of printed circuit boards, integrated circuits, and other parts. + +In summary, any ICT goods, including end-user goods, which can be part of a network delivering voice and/or data lies within the scope of this Recommendation. A hierarchical view is suitable for describing networks. At the top level, different types of ICT goods can be identified, e.g., network nodes, end-user goods, and services such as videoconferencing. + +#### 7.2.2 Functional unit + +##### 7.2.2.1 General + +It is required to define a functional unit for the LCA. The functional unit shall be chosen in accordance with the goal and scope of the LCA. An ICT good, network, or service has a number of possible functions and the one(s) selected for an LCA depend(s) on the goal and scope of the specific LCA. For example, a mobile phone/device may have several functions: phone calls, text messaging, emailing, Internet use, camera, music player, etc. + +The functional unit defines the performance characteristics delivered by the ICT goods, networks and services being studied. The functional unit shall have a function and a quantifiable unit measuring the performance of that function. + +The functional unit requires inclusion of the relevant quantifiable properties and the technical/functional performance of the system. This means that the operating lifetime of all included ICT goods shall be specified, and also the number of users/subscribers supported by the network and the traffic profile shall be included, where applicable. + +The primary purpose of a functional unit is to provide a *reference* to which the inputs and outputs are related or normalized (in a mathematical sense). Such a reference is necessary to ensure comparability of LCA results. Comparability of LCA results is particularly critical when different systems are being assessed, to ensure that such comparisons are made on a common basis. Equivalency between two systems shall be ensured by the selection of a relevant function and functional unit. + +NOTE 1 – Comparisons are only possible if assumptions and other conditions are equivalent. + +NOTE 2 – The identification of the common basis could be challenging for comparisons of ICT services and reference product systems. It is important to determine the reference flow in each product system, in order to fulfil the intended function, i.e., the amount of products needed to fulfil the function. + +NOTE 3 – Depending on the scope of the LCA assessment and the function(s) of the ICT good selected, the relevant intensity feature and performance parameter might vary; therefore, the LCA practitioner should consider these aspects when defining the functional unit. + +The functional unit shall be clearly defined and measurable. + +Based on the functional unit, the reference flow (amount of ICT goods, ICT network or ICT service needed to fulfil the function) is determined. The reference flow shall reflect the chosen functional unit. + +Example (storage server): + +The function of storage servers is to provide formatted capacity. The functional unit is 'A storage subsystem providing one terabyte of formatted capacity to be suited for the needs of the purchasing customer for one year'. + +The reference flow is $(\text{Life Cycle Inventory}) / (\text{Capacity (TB)} \times \text{Lifetime(year)})$ + +Example (laptop): + +The function experienced by a user of an (offline) laptop is the ability to handle documents, use multimedia, etc. The corresponding functional unit could then be usage of laptop applications, ten hours per week during an operating lifetime (e.g., 4 years). The corresponding reference flow is defined as one laptop sales package. + +Comparing LCAs and tracking performance changes over time require that the assessments are based on the same function and functional unit. Therefore, selecting the right function(s) of the studied product is crucial to track emission reductions over time. + +Quantitative and qualitative aspects needed to define the function should be considered when defining the functional unit, e.g., data transmitting speed for a certain quality level, the number of users/subscribers supported and the traffic profile. + +A well-defined functional unit thus considers the following aspects: + +- The magnitude of the function or service +- The duration or operating lifetime of that function or service +- The expected level of quality. + +Specific attention on selection of the functional unit for goods is needed if the goal of the result from the LCA study is to communicate the results to the public in order to enable a correct interpretation of the results. + +NOTE 4 – Comparisons are only possible if assumptions and other conditions are equivalent. + +The explanation of the common basis could be challenging for comparisons of ICT services and reference product systems. It is important to determine the reference flow in each product system, in order to fulfil the intended function, i.e. the amount of products needed to fulfil the function. + +##### 7.2.2.2 ICT goods + +The functional unit shall be chosen in the context of the goal and scope of the LCA and shall be further clarified by system boundary and cut-off rules. *ICT goods* LCA results may be further used as the basis for *networks* and *services* LCA. + +To comply with this Recommendation, the following functional unit shall be applied where applicable. + +- Annual ICT goods use (per one year of ICT good use), or +- Total ICT good use per lifetime of ICT good. + +For relevant LCA results, realistic use scenarios shall be captured. Additionally, other more specific functional units may be applied as well based on the scope and purpose of the LCA. + +For ICT goods, additional more specific functional units may also be considered when the result is presented, e.g., the time during which one uses a phone and the number of e-mails sent. The reference flow could be one sales package of an ICT good (e.g., one server, one PC or one phone), including all inbox materials. Packages may vary from one package to another package or from company to company; the content considered should be described in the assessment together with the results. + +Specifically, for ICT network infrastructure goods intensity features are often suitable for the functional unit, e.g., product system providing a certain capacity per year, with the typical reference flow being 'life cycle inventory/(capacity of product $\times$ lifetime of product)'. + +Example (mobile phone): + +The function of the overall usage of a mobile phone is studied from 'cradle to the grave'. The mobile phone provides several subfunctions, e.g., phone calls, text messages, e-mails, use of Internet, camera and music player, but in this case the aggregated use of the phone is the focus. The function is thus the provision of smart phone capabilities. The functional unit is then 'the use of a model X smartphone during an operating lifetime of three years'. The reference flow is one sales package of the model X smartphone. + +Example (software): + +The function experienced by a user of a word processor program is to deliver word processing of documents electronically. The corresponding functional unit could then be the number of pages processed per time unit (e.g., one hour) during the operating lifetime (e.g., three years). Furthermore, the reference flow is defined as one unit of word processing software (distributed e.g., in a compact disc (CD) with packaging). + +##### 7.2.2.3 ICT networks + +ICT networks can be seen as a system composed of different types of ICT goods. For the purposes of this Recommendation, the following functional unit shall be applied, where applicable, for ICT networks used for at least one year: + +- Annual network use. + +For relevant LCA results, realistic use scenarios shall be captured. + +Additionally, other more specific functional units may be applied based on the scope and purpose of the LCA, for instance: annual network use per number of users, or per transmitted data, or coverage area (if applicable). + +The annual network use should be defined with respect to a traffic scenario to make it possible to define the reference flow, i.e., the number of different node types needed to perform the intended function. + +If using more specific functional units, it is recommended to base them on data which is easily understood by the users, e.g., the functional unit of the circuit switching type and the packet switching type should be expressed in terms of communication time and amount of information, respectively. + +To achieve consistency between LCAs for ICT, it is recommended to always use the basic functional unit and then to add others as needed. + +It shall be noted that comparison between different systems shall reflect the information flow as well. Furthermore, [ISO 14040] and [ISO 14044] standards state that comparison between results from different studies is not allowed unless the studies are based on the same assumptions. The conclusion is that great care shall be taken before using such studies for any kind of comparison to other systems. + +Example (ICT network): + +A mobile telecommunication system has a large number of different functions working on different system levels. From an end-user customer point of view the basic function of a mobile communication + +system is to be able to communicate. The basic functionality of a mobile communication system is thus the possibility to communicate with speech and data "anywhere, anytime". + +The functional unit is "one year of operation of a mobile communication system". To be able to make comparisons between different systems, and to make the functional unit unambiguous, it shall be noted that the mobile communication system shall be defined further, with a number of factors such as the number of subscribers and the coverage area. A traffic model shall also be defined. It is possible also to relate the results of one system to the number of subscribers it supports. The functional unit may then be expressed as "one year of operation of a mobile communication system per subscriber". + +The reference flow is the number of goods needed to perform the requested function. + +##### 7.2.2.4 ICT services + +For the purposes of this Recommendation, the following functional unit shall be applied where applicable. + +- Annual service use. + +For relevant LCA results, realistic use scenarios shall be captured. + +Additionally, other more specific functional units may be applied based on the scope and purpose of the LCA. + +Corresponding realistic use scenarios shall be defined. The *annual service* use shall be defined with respect to the usage scenario to make it possible to define the reference flow, i.e., a series of ICT goods involved with an ICT service to perform the functional unit. Generally, these amounts are based on an allocation of network capacity between the service under study and other services. + +#### 7.2.3 System boundaries + +##### 7.2.3.1 General + +The system boundaries define the unit processes across the life cycle of the studied ICT goods, networks and services that are to be assessed in terms of data collection and calculation of environmental load. + +The life cycle stages and the unit processes that shall apply to the analysed product system are those required for providing its function as defined by its functional unit. The selection of the system boundary shall be consistent with the goal of the study. Consequently, the system boundaries here define the life cycle stages and the unit processes that shall be taken into account in an LCA of an ICT product system. + +Figure 7 shows the system boundary of an LCA of ICT goods, networks and services. The boxes A to D denote the life cycle stages of the ICT product system. The boxes for G1 to G7 in Figure 7 denote generic processes that reoccur several times during these life cycle stages. These processes are further defined in Annex D. + +![Figure 7: The system boundary of the product system for LCAs of ICT goods, networks or services. The diagram shows a large rounded rectangle representing the system boundary. Inside, on the left, are external inputs: G1 Transport and travel, G2 Electricity supply, G3 Fuel supply, G4 Other energy supply, G5 Raw material acquisition (G5.1 Raw material extraction, G5.2 Raw material processing), G6 End-of-life treatment (G6.1 EHW treatment, G6.2 Other waste treatment), and G7 Raw material recycling. On the right, the internal stages are: A: Goods raw material acquisition (A1 Raw material extraction, A2 Raw material processing), B: Production (B1 ICT goods production (B1.1 Parts production, B1.2 Assembly, B1.3 ICT manufacturer support activities), B2 Support goods production (B2.1 Support goods manufacturing), B3 ICT-specific site construction), C: Use (C1 ICT goods use, C2 Support goods use, C3 Operator support activities, C4 Service provider support activities), and D: Goods end-of-life treatment (D1 Preparation for extended operating lifetime, D2 ICT-specific EoLT (D2.1 Storage/disassembly/dismantling/shredding, D2.2 Recycling), D3 Other EoLT). A legend at the bottom indicates a white box represents the 'System boundary'.](e451401f8fa77b466f401d5fce15b26c_img.jpg) + +Figure 7: The system boundary of the product system for LCAs of ICT goods, networks or services. The diagram shows a large rounded rectangle representing the system boundary. Inside, on the left, are external inputs: G1 Transport and travel, G2 Electricity supply, G3 Fuel supply, G4 Other energy supply, G5 Raw material acquisition (G5.1 Raw material extraction, G5.2 Raw material processing), G6 End-of-life treatment (G6.1 EHW treatment, G6.2 Other waste treatment), and G7 Raw material recycling. On the right, the internal stages are: A: Goods raw material acquisition (A1 Raw material extraction, A2 Raw material processing), B: Production (B1 ICT goods production (B1.1 Parts production, B1.2 Assembly, B1.3 ICT manufacturer support activities), B2 Support goods production (B2.1 Support goods manufacturing), B3 ICT-specific site construction), C: Use (C1 ICT goods use, C2 Support goods use, C3 Operator support activities, C4 Service provider support activities), and D: Goods end-of-life treatment (D1 Preparation for extended operating lifetime, D2 ICT-specific EoLT (D2.1 Storage/disassembly/dismantling/shredding, D2.2 Recycling), D3 Other EoLT). A legend at the bottom indicates a white box represents the 'System boundary'. + +L.1410(24) + +**Figure 7 – The system boundary of the product system for LCAs of ICT goods, networks or services** + +Table 2 includes further details of the life cycle stages to be included in LCAs of ICT goods, networks and services. The different life cycle stages are further described in clauses 7.2.3.3.2 to 7.2.3.3.5. Mandatory life cycle stages or unit processes shall not be cut off before considered for inclusion by using alternative data. However, on a more detailed level, not all life cycle processes apply to all product systems, e.g., even if parts production (B1.1, Figure 9) is mandatory, not all parts given in Annex E are applicable to all studied product systems. + +**Table 2 – Classification of life cycle stages/unit processes** + +| Tag | Life cycle stage/Process | Unit process | Class | | | +|-----|-------------------------------|--------------|-----------|-----------|-----------| +| | | | ICT good | Network | Service | +| A | Good raw material acquisition | | | | | +| A1 | Raw material extraction | | Mandatory | Mandatory | Mandatory | +| A2 | Raw material processing | | Mandatory | Mandatory | Mandatory | +| B | Production | | | | | +| B1 | ICT good production | | | | | + +**Table 2 – Classification of life cycle stages/unit processes** + +| Tag | Life cycle stage/Process | | Unit process | Class | | | +|------|--------------------------------|--------------------------------------------------|---------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------|-------------|-------------| +| | | | | | | | +| B1.1 | | | Parts production (for further details refer to Annex E) | Mandatory | Mandatory | Mandatory | +| B1.2 | | | Assembly (see Note 2) | Mandatory | Mandatory | Mandatory | +| B1.3 | | | ICT manufacturer support activities | Recommended | Recommended | Recommended | +| B2 | Support goods production | | | | | | +| B2.1 | | | Support goods manufacturing | Mandatory if support goods are included in the studied product system | Mandatory | Mandatory | +| B3 | ICT-specific site construction | | | | | | +| B3.1 | | | Construction of ICT-specific site (see Notes 1 and 3) | Mandatory if site construction is included in the studied product system.
Recommended if support goods are included in the studied product system. | Recommended | Recommended | +| C | Use | | | | | | +| C1 | | ICT goods use | | Mandatory | Mandatory | Mandatory | +| C2 | | Support goods use | | Mandatory if support goods are included in the studied product system | Mandatory | Mandatory | +| C3 | | Operator support activities (see Note 3) | | Optional | Recommended | Recommended | +| C4 | | Service provider support activities (see Note 3) | | Not applicable | Optional | Recommended | +| D | Goods end-of-life treatment | | | | | | +| D1 | | Preparation of ICT goods for extended | | Mandatory | Recommended | Recommended | + +**Table 2 – Classification of life cycle stages/unit processes** + +| Tag | Life cycle stage/Process | Unit process | Class | | | +|------|--------------------------|-----------------------------------------------|------------------|------------------|------------------| +| | | | | | | +| | operating lifetime | | | | | +| D2 | ICT-specific EoLT | | | | | +| D2.1 | | Storage/Disassembly/
Dismantling/Shredding | Mandatory | Mandatory | Mandatory | +| D2.2 | | Recycling | Mandatory | Mandatory | Mandatory | +| D3 | Other EoLT | | Mandatory | Mandatory | Mandatory | + +NOTE 1 – Include both construction of site for support goods and ICT goods. +NOTE 2 – This includes soldering of PCBAs. +NOTE 3 – These are not applicable for end-user goods. +NOTE 4 – Support activities include installation and de-installation of ICT end-user goods (e.g., IoT devices, Set-Top Boxes, End-user terminals ...). Depending on the business model, these activities may be qualified as 'operator support activities' or 'service provider support activities'. Example: Considering the case of a smart metering service deployed by a service provider within households/organizations, the installation and de-installation activities of smart meters within households and organizations would be considered as service provider support activities. + +In Table 2 'Mandatory' means that the life cycle stage, if applicable to the studied product system, shall always be taken into account in an LCA for ICT. + +A more detailed overview (Figure II.1), showing the detailed content and connection between all life cycle stages, is shown in Appendix II. Guidance on how to interpret Table 2 for different stakeholders is given in clause 7.2.5.2. + +All stages in the life cycle are associated with various kinds of organizational activities, referred to in this Recommendation as support activities. The term support activities include the activities directly associated with the deliverables of the organization, e.g., development, marketing and sales. Additionally, it covers all other activities needed for the organization to function, e.g., researchers, human resources staff, educational staff, etc. allocated to the reference flow. All these different categories involve the use of buildings and travel. For the ICT manufacturer, operator and service providers the support activities are explicitly indicated in Table 2 (B1.3, C.3 and C.4) and specified in clauses 7.2.3.3.3 to 4. For all other activities of Table 2, support activities are seen as an integrated part of the activity. It is recommended to include the impact from support activities wherever possible. See Annex C. + +NOTE – It could be argued that support activities representing processes under the financial or operational control of the organization undertaking the LCA should be mandatory to include, whereas others are seen as optional. In this Recommendation, all support activities are handled equally, as this approach would provide better figures for companies with a higher degree of outsourcing. + +##### 7.2.3.2 The use of unit processes + +Each life cycle stage (A to D) is further refined into activities, referred to as unit processes, which represent the basic physical flows (materials and energy) of the life cycle. + +A unit process typically represents a production facility but can also model an office or even a vehicle. Annexes B and G and Appendix II, provide more details on modelling of unit processes and applicable inputs and outputs. + +##### 7.2.3.3 ICT goods + +###### 7.2.3.3.1 General + +The system boundary of the ICT goods should encompass all life cycle stages specified in clause 7.1.1 and in Table 2. + +In order to set the system boundary of ICT goods, the life cycle stages listed in clause 7.1.1 shall be detailed. Further guidance is given in Table 2, Annex D, Annex E, Annex F and Appendix II. As stated in clause 7.1.4, the environmental impact from both hardware and software shall be considered, if applicable. + +For the ICT good under study, applicable types of parts, as well as the amounts of these, shall be defined. + +In-depth information about the product composition is required before setting the system boundary of the product, as described in clause 7.1.3.1. The detailed content and connection between all life cycle stages and the different processes are further described in Appendix II. + +###### 7.2.3.3.2 Goods raw material acquisition + +*Goods raw material acquisition (A)* **starts** with the extraction (A1) of natural resources (e.g., iron ore, crude oil, etc.) and **ends** with the transport of *raw materials* from raw materials processing (A2) to part production facilities. A2 deals with the processing of extracted *raw materials* (e.g., iron ore pellets) into processed *raw materials* (e.g., steel sheet, copper wire, etc.). *goods raw material acquisition* is the life cycle stage for ICT goods as defined in Figure 8. + +As *raw materials* are used as additives in every life cycle stage, *raw material acquisition* can additionally be regarded as a generic process (G5). + +Annex H (Table H.1) provides a mandatory set of *raw materials* (both ICT-specific and generic) which shall be included in the LCA of ICT goods. + +As shown in Figure 8, raw material extraction and raw material processing are within the system boundary of raw materials acquisition. + +![Flowchart of goods raw material acquisition system boundary](f10dc32e3673e1392029a49e958a9d6c_img.jpg) + +The diagram illustrates the system boundary for goods raw material acquisition. A large rounded rectangle, labeled 'System boundary' in the legend, encloses two boxes: 'A1 Raw material extraction' at the top and 'A2 Raw material processing' at the bottom, with a downward arrow between them. An arrow points from the right side of the 'System boundary' box to an external box labeled 'B. Production'. Below the 'System boundary' box, a box labeled 'G7 Raw material recycling' has a dashed upward arrow pointing into the 'System boundary' box. A legend at the bottom shows a small rectangle next to the text 'System boundary' and the code 'L.1410(14)\_F08'. + +Flowchart of goods raw material acquisition system boundary + +**Figure 8 – The system boundary of goods raw material acquisition in LCA of ICT goods** + +###### 7.2.3.3.3 Production + +Production (B) **starts** with the parts production and **ends** with the transportation of ICT goods and support goods to 'Use' (C). The system boundary for production, shown in Figure 9, includes ICT goods production and support goods production. + +NOTE 1 – Detailed flow chart figures are provided in each unique LCA project. + +It is optional to include the construction of plants in which the ICT goods are assembled. + +In case *support goods* is part of the studied product system, *support goods production (B2)* is mandatory. + +It is optional to include the construction of plants in which the *support goods* are assembled. + +As a starting point B2 and B3 are optional for *ICT goods* LCAs as the variance in solution may vary significantly both for B2.1 and B3.1 between markets and operators. + +NOTE 2 – However, for LCAs referring to specific conditions it is encouraged to include also B2 and B3 in the studied ICT product system as support goods can have a significant impact on the use stage for an ICT solution. + +![Flowchart of the system boundary of production in LCA of ICT goods. The diagram shows a vertical flow of processes within a system boundary, with external inputs and outputs.](0b3d9fe35da3ee0c88f1420bb9ed7a03_img.jpg) + +The diagram illustrates the system boundary for the production of ICT goods in an LCA. It features a vertical flow of processes enclosed in a large rounded rectangle labeled 'System boundary'. The processes, from top to bottom, are: B1.1 Parts production (which includes sub-processes B1.1.1 Batteries, B1.1.2 Cables, B1.1.3 Electro-mechanics, B1.1.4 Integrated circuits, B1.1.5 Mechanics / materials, B1.1.6 Displays, B1.1.7 PCBs, B1.1.8 Other PCBA components, B1.1.9 Packaging materials, B1.1.10 Black box modules, and B1.1.11 Software), B1.2 Assembly, B1.3 ICT manufacturer support activities, B2.1 Support goods manufacturing, and B3 ICT-specific site construction. Downward arrows connect B1.1 to B1.2, B1.2 to B1.3, B1.3 to B2.1, and B2.1 to B3. An upward arrow connects B3 to B1.3. External to the system boundary, box 'A. Goods raw material acquisition' has an upward arrow pointing to B3. Box 'C. Use' has a rightward arrow pointing to B1.3. Box 'D. EoLT' has a rightward arrow pointing to B1.3. A legend at the bottom shows a small rectangle next to the text 'System boundary'. + +L.1410(24) + +Flowchart of the system boundary of production in LCA of ICT goods. The diagram shows a vertical flow of processes within a system boundary, with external inputs and outputs. + +**Figure 9 – The system boundary of production in LCA of ICT goods** + +The *ICT goods production (B1)* consists of *parts production (B1.1)* and *assembly (B1.2)*, as well as *ICT manufacturer support activities (B1.3)*. + +For refurbished ICT goods, "B1 ICT goods production" and "B2 Support goods production" include the environmental impact associated with the refurbishment production process (making the ICT goods fit for next use). Refurbishment process may use new, reused, or refurbished parts and/or support goods. The respective environmental impact of these parts needs to be considered and included in B1 as relevant. The refurbishment process often consists of inspection, cleaning, repair and replacement of worn/out parts, quality testing, etc. The environmental impact due to these activities shall be included when they occur in the respective unit process. + +Annex E lists a mandatory set of **parts** to be included where applicable to the studied ICT product system, when performing an LCA of ICT goods, as well as mandatory part unit processes which shall be included for each part. + +As an example, if batteries are part of the studied *ICT goods* product system, they shall be included within the system boundary, and for every battery, the battery cell manufacturing and battery module manufacturing shall be included. Except for **parts** listed in Annex E, other **parts** may be as important and should be considered as well. + +Note that **parts** can be complex modules themselves consisting of several other **part** types as building blocks. + +The **Assembly (B1.2)** shall include as minimum PCBA module assembly, final assembly, warehousing, and packaging. + +For B1.2 it is optional to include 'Testing and repair'. + +NOTE 3 – Production yields may have an influence on the final results. + +If included, for ICT manufacturer support activities (B1.3) see general guidance on support activities Annex C. + +Support goods (B2.1) which shall be included if applicable to the studied product system include at least air conditioners, cables, and power supply systems. + +As stated in Table 2, construction of ICT-specific site (B3) is mandatory if the ICT-specific site is included in the studied product system. Depending on the specific case at hand, a site can be pre-produced or constructed on place. Site building blocks to be included in B3.1, if they are applicable to the studied product system, are antenna towers, fences and shelters. + +Support activities for the ICT manufacturer (B1.3) are specifically indicated in Figure 9. Regarding other support activities for support goods production and parts production, see clause 7.2.3.1. + +###### 7.2.3.3.4 Use + +The use stage starts with the installation of ICT goods and support goods and ends with de-installation just before the transportation to EoLT. As shown in Figure 10, the use stage includes ICT goods use (C1), support goods use (C2), operator support activities (C3), and service provider support activities (C4). + +(C1) and (C2) include energy supply during the operating lifetime of the ICT goods. + +Operator support activities (C3) which should at least be included are installation and de-installation of ICT goods and operation and maintenance of the ICT goods and support goods, including associated transport and travel. The maintenance includes replacing, e.g., PCBAs. Raw material acquisition and production for the additional PCBAs and other goods used during the operating lifetime of the ICT goods are mandatory. The additional raw material acquisition and production impacts from spare parts and support goods are reported in raw material acquisition and production and EoLT results. The spare parts management is typically shared between ICT goods manufacturer and the operator and should be considered if applicable to the studied system. + +Service provider support activities (C4) see general guidance on support activities Annex C. + +NOTE – An example of a service provider support activity is the development of an "app" for smart phones. + +![Figure 10: The system boundary of use in LCA of ICT goods. The diagram shows a large rounded rectangle representing the 'System boundary'. Inside this boundary are four stacked boxes: 'C1 ICT goods use', 'C2 Support goods use', 'C3 Operator support activities' (which includes sub-items C3.1 Installation, C3.2 Operation and maintenance, and C3.3 De-installation), and 'C4 Service provider support activities'. Below the main boundary box is a separate box labeled 'B. Production', with an arrow pointing up into the main boundary. To the right of the main boundary box is a box labeled 'D. EoLT', with two arrows pointing between it and the main boundary (one in each direction). A legend at the bottom shows a small rectangle next to the text 'System boundary'. The code 'L.1410(14)_F10' is in the bottom right corner.](0b7849dae424b0dd33e6386d2384643a_img.jpg) + +Figure 10: The system boundary of use in LCA of ICT goods. The diagram shows a large rounded rectangle representing the 'System boundary'. Inside this boundary are four stacked boxes: 'C1 ICT goods use', 'C2 Support goods use', 'C3 Operator support activities' (which includes sub-items C3.1 Installation, C3.2 Operation and maintenance, and C3.3 De-installation), and 'C4 Service provider support activities'. Below the main boundary box is a separate box labeled 'B. Production', with an arrow pointing up into the main boundary. To the right of the main boundary box is a box labeled 'D. EoLT', with two arrows pointing between it and the main boundary (one in each direction). A legend at the bottom shows a small rectangle next to the text 'System boundary'. The code 'L.1410(14)\_F10' is in the bottom right corner. + +**Figure 10 – The system boundary of use in LCA of ICT goods** + +###### 7.2.3.3.5 End-of-life treatment (EoLT) + +EoLT **starts** with the transport of de-installed *ICT goods* and/or *support goods* to storage, factory or recycling center, and **ends** either after *preparation of ICT goods for extended operating lifetime (D1)* when the product starts its second life cycle or when ICT goods and support goods go through end-of-life treatment ("D2 ICT specific EoLT" or "D3 Other EoLT"). + +NOTE – The first destination for the de-installed ICT goods depends on the goal and scope of the specific LCA study (studied ICT product system). + +As shown in Figure 11, *preparation of ICT goods for extended operating lifetime (D1)*, *ICT-specific EoLT (D2)* and *other EoLT (D3)* are within the mandatory system boundary for EoLT depending on the appropriate route for the specified ICT good at hand. + +Extended operating lifetime can be achieved by different actions such as refurbishment or reuse. It should be noted that although repair serves the purpose of extending the operating lifetime of ICT goods, repair activities do not belong to EoLT stage. + +*ICT-specific EoLT* is applicable to the *ICT goods* itself and also applies to ICT based *support goods*. + +*Other EoLT* mainly deals with non-ICT based *support goods*. + +After the EoLT starts *raw material recycling (G7)* and/or *production (B)* in case of ICT goods intended for refurbishment, depending on the decision made during the *prepare for extended operating lifetime (D1)*. + +![Diagram of the system boundary of goods EoLT in LCA of ICT goods. The diagram shows a flow from 'C. Use' to a large system boundary box containing 'D1 Prepare for extended operating lifetime', 'D2 ICT-specific EoLT' (with sub-processes D2.1, D2.2, and D2.2.1-5), and 'D3 Other EoLT'. 'D1' leads to 'B Production'. 'D2' leads to 'G7 Raw material recycling'. 'D3' is an internal process. A legend indicates that a rectangle represents the 'System boundary'.](798679874d1c29f8343506a156c79d7e_img.jpg) + +``` + +graph TD + C[C. Use] --> DB[ ] + subgraph DB [System boundary] + D1[D1 Prepare for extended operating lifetime] + D2["D2 ICT-specific EoLT +D2.1 Storage/dismassembly/ +dismantling/shredding +D2.2 Recycling +D2.2.1 Battery recycling +ICT-specific metal/mechanical +parts/fractions EoLT +D2.2.2 PCBA recycling +D2.2.3 Cable recycling +D2.2.4 Mechanics recycling +D2.2.5 Other ICT part recycling"] + D3[D3 Other EoLT] + end + D1 --> B[B Production] + D2 --> G7[G7 Raw material recycling] + style DB fill:none,stroke:none + style C fill:none,stroke:none + style B fill:none,stroke:none + style G7 fill:none,stroke:none + style D1 fill:none,stroke:none + style D2 fill:none,stroke:none + style D3 fill:none,stroke:none + +``` + +Diagram of the system boundary of goods EoLT in LCA of ICT goods. The diagram shows a flow from 'C. Use' to a large system boundary box containing 'D1 Prepare for extended operating lifetime', 'D2 ICT-specific EoLT' (with sub-processes D2.1, D2.2, and D2.2.1-5), and 'D3 Other EoLT'. 'D1' leads to 'B Production'. 'D2' leads to 'G7 Raw material recycling'. 'D3' is an internal process. A legend indicates that a rectangle represents the 'System boundary'. + +**Figure 11 – The system boundary of goods EoLT in LCA of ICT goods** + +The ICT-specific EoLT (D2) in an LCA of ICT goods includes transport from use to storage, factory, refurbishment or recycling centre (D2.1), and recycling processes D2.2.1-5 for batteries, PCBAs, cables, mechanics and other ICT parts. + +The output from these recycling processes is not raw materials but rather products which the raw material recycling (G7) can use (e.g., lead anode from D2.2.1, copper wire from D2.2.3, aluminium frame from D2.2.4, plastic constituent of cartridge from D2.2.5). + +It has to be determined on a case-by-case which treatments (PCBA, recycling, etc.) shall apply to ICT goods and support goods, respectively. + +Annex F lists a mandatory set of EoLT processes to be included, where applicable, when performing an LCA of ICT goods which includes the EoLT stage. + +###### 7.2.3.3.6 ICT goods and processes for extended operating lifetime + +Figure 12 illustrates the LCA stages of an ICT product, supporting multiple life cycles. The stage "D1 preparation of ICT goods for extended operating lifetime" includes the decision point where the product is evaluated to determine whether it should proceed to refurbishment or reuse, or waste treatment. Correspondingly, "B Production" includes "B1 ICT goods production", where the processes such as refurbishment process for extended operating lifetime are carried out. + +![Flowchart of life cycle stage details for refurbished ICT goods. The cycle starts with A. Raw material acquisition, leading to B. Production (which includes B1. ICT goods production). B leads to C. Use. C leads to D. EoLT (End of Life Time), which includes D1. Preparation of ICT goods for extended operating lifetime, D2. ICT-specific EoLT, and D3. Other EoLT. D leads to G6. EoLT and G7. Raw material recycling. There are feedback loops from C to A and from D back to B.](cbb2d311b20781a595488445ded48d0a_img.jpg) + +``` + +graph TD + A[A. Raw material acquisition] --> B[B. Production] + B --> C[C. Use] + C --> A + C --> D[D. EoLT] + D --> B + subgraph B [B. Production] + B1[B1. ICT goods production] + end + subgraph D [D. EoLT] + D1[D1. Preparation of ICT goods for extended operating lifetime] + D2[D2. ICT-specific EoLT] + D3[D3. Other EoLT] + D1 --> D2 + D2 --> D3 + end + D --> G6[G6. EoLT] + D --> G7[G7. Raw material recycling] + +``` + +Flowchart of life cycle stage details for refurbished ICT goods. The cycle starts with A. Raw material acquisition, leading to B. Production (which includes B1. ICT goods production). B leads to C. Use. C leads to D. EoLT (End of Life Time), which includes D1. Preparation of ICT goods for extended operating lifetime, D2. ICT-specific EoLT, and D3. Other EoLT. D leads to G6. EoLT and G7. Raw material recycling. There are feedback loops from C to A and from D back to B. + +**Figure 12 – Life cycle stage details for refurbished ICT goods** + +##### 7.2.3.4 ICT networks + +The aggregated impact of an ICT network equals the sum of the impact from the different goods constituting the ICT network. When aggregating results, data should be based on equivalent assumptions or use scenarios. + +As the ICT network operation depends on several types of software, including the software program needed to run the primary subscription service, as outlined in applicable standards (e.g., 3GPP for long term evolution (LTE)), the impact from the development of such software should be included in the assessment. + +For each type of ICT good constituting the ICT network, the rules defined for ICT goods in this Recommendation shall apply. + +Though it is acknowledged that LCA results for ICT goods that comply with this Recommendation may not be available for all ICT goods, such data takes precedence over other data. The network shall be defined in terms of ICT goods, support goods and ICT infrastructure (e.g., cables duct). For each included product types, the number of units shall be defined, as well as their corresponding lifetimes. For each type of ICT goods the rules defined for ICT goods in this Recommendation applies for the assessment. For reporting, the same reporting rules apply, but it is also allowed to aggregate the results to network level. + +Appendix IV shows typical ICT goods of which the network consists. + +As stated before, each of these goods is associated with support goods for powering and cooling, as well as the ICT-specific site infrastructure. + +For the assessment of networks, operator activities shall always be included. + +Services provider activities and data centres are to be seen as recommended activities. + +##### **7.2.3.5 ICT services** + +###### **7.2.3.5.1 General** + +The operation of an ICT network could be described as the operation of several ICT services working in parallel, among which there is the primary subscription service which allows transfer of voice and data, but also different applications. Thus, to calculate the impact of an ICT service, it is generally necessary to assess the ICT network, as outlined in the previous clause, and if necessary (i.e., in a multi-service situation) allocate an appropriate amount of this impact to the ICT service under study. For details on allocations refer to clause 7.3.3.9. + +The system boundary requirements defined for ICT networks shall apply also to ICT services but with some additions, listed below. + +In addition to the use of ICT goods and networks, an ICT service may also have additional impacts associated with application software development, use of consumables, infrastructure for sales and logistics, associated travel and transport (in addition to those already included for the ICT goods and networks) which shall also be included as appropriate. Often, these activities are part of the overall service provider activities. + +The impact of the data centres where the service is operated shall be assessed. The associated activities of the service provider should also be considered. Service provider support activities consist of, e.g., offices and business travel, like operator support activities and may also include the activities listed above. + +Important data that defines the hardware associated with the service is the number of servers, storage and network goods units, their energy consumption and the data centre overhead energy consumption for cooling and power systems (including back-up power). + +The data centre shall be studied and assessed in the same way as other ICT goods and support goods. + +The usage of the ICT services provided by the ICT network shall be established based on the actual use scenario of the ICT services. + +If the actual scenario is unavailable, an estimated use scenario can be used which e.g., cover the energy consumption, any waste disposal or emissions due to the services during the period which the services are provided. + +It is optional to include the production/realization of the data centre infrastructure, e.g., the construction of the data centre building and cooling and power infrastructure. + +NOTE – If the ICT service offers the possibility to replace an already existing service reference product system (i.e., an e-health solution replacing hospital visits), a comparative study that includes the reduced impact from this change has to be carried out to get a more complete understanding of the impact of the service. For further details refer to Part II. + +###### **7.2.3.5.2 Eight items to consider** + +The following eight checklist items should be considered in the system boundary setting of ICT services, including their associated goods and networks, to identify activities associated with their life cycle and usage. + +These checklist items may then also be used to structure data and reporting, but other structures are also possible. + +NOTE – It is important to avoid double-accounting between the eight checklist items. + +###### **1) ICT hardware** + +This checklist item refers to the life cycle impact of ICT goods and networks, for instance PCs, printers, base stations or core nodes. The use of materials and the energy consumption should be + +considered at each life cycle stage. See previous clauses (7.2.3.3 ICT goods, 7.2.3.4 ICT networks) for details. + +###### **2) ICT software** + +This checklist item refers to the life cycle impact (including design, development and use) of ICT software (e.g., individual software, packages, middleware and operating systems). Examples of software impact are the use of electricity and paper by the designers. See clause 7.2.3.5.1 for details. + +NOTE – In practice it may be hard to assess use of software and hardware separately. + +###### **3) Consumables and other supportive products** + +This checklist item refers to the life cycle impact of consumables and other supportive products needed for the utilization of the ICT product system. The supportive products include for instance, information printouts, information media (e.g., CDs and digital versatile discs (DVDs)) and printer cartridges. + +###### **4) Site infrastructure** + +This checklist item refers to life cycle impact of facilities providing ICT-related services for the assessed ICT (ICT sites) and associated goods, e.g., cooling and power supply. Depending on the scope of the assessment, buildings could also be considered. Examples of sites are base station (BS) sites and data centres. + +###### **5) Transport (movement of goods)** + +This checklist item refers to the impact from transportation of all the goods within the ICT product system boundary except ones included in '1) ICT hardware' or 'ICT software'. Examples of such goods are courier of documents and delivery of newspaper. This includes use of fuels as well as fuel supply chains of trucks, trains, planes, etc. + +NOTE – Except for fuel supply chain, only use stage need to be considered for transport. + +###### **6) Travel (movement of people)** + +This checklist item refers to the impact from travel, not related to ICT hardware and software. This checklist item includes commuting, professional travel and travel by customers depending on the scope and purpose of the study. It includes the use of fuels as well as the fuel supply chains of cars, trains, buses, etc. + +###### **7) Storage of goods** + +This checklist item refers to the storage of products not related to ICT hardware and software such as ICT goods, document archives, etc., in an applicable storage place. This particularly implies that the energy consumption for cooling and lighting should be considered. + +###### **8) Working environment** + +This checklist item refers to the use of working environments by the personnel of an organization for business purposes, which are not related to ICT hardware and software. This checklist item mainly deals with the use of buildings, but potentially, the building life cycle could also be considered. The associated impact includes the energy consumption from cooling or heating systems, lighting, PCs, etc. This checklist item includes all utilization of the working environment applicable to all the other checklist items. + +NOTE – The office could sometime be located in a factory or a home. Production areas of factories belong to checklist item 1. + +Annex K defines a method which shall be considered for assessing the environmental impact of the working environment. + +The intention of the eight checklist items above is to ensure that all relevant impacts are considered for all life cycle stages when defining the impact from a product system viewpoint. These are typical items to be often considered, but other items may be considered as well depending on study. + +For example, the assessment of a telepresence service may include ICT hardware (telepresence audio sets, networks, and servers), ICT software (telepresence software), site infrastructure (facility for servers), travel (business trip for setting telepresence system and having meetings) and working environment (cooling and lighting of the meeting room) may be needed to consider. + +Table 3 below illustrates the relationships between the checklist items and the life cycle stages. + +**Table 3 – Mapping of checklist items on life cycle stages** + +| Life cycle stage/Category | Raw material acquisition | Production | Use | EoLT | +|-------------------------------------------|--------------------------|------------|-----|------| +| ICT hardware | | | | | +| ICT software | | | | | +| Consumables and other supportive products | | | | | +| Site infrastructure | | | | | +| Transport (movement of goods) | | | | | +| Travel (movement of people) | | | | | +| Storage of goods | | | | | +| Working environment | | | | | + +The purpose of Table 3 is to check whether all relevant items for data collection are included. It may not be part of the overall assessment reporting. + +Energy consumption, material inputs and environmental releases shall be assessed in accordance with the system boundary. The checklist items above should be considered to structure energy and material inputs and environmental releases. + +In terms of assessment, the checklist items may be considered separately or together depending on the purpose and scope of the study. Also, whether this table is for internal purpose or for public disclosure depends on the study. + +#### 7.2.4 Cut-off rules + +NOTE 1 – Clause 4.2.3.3.3 of [ISO 14044] also applies. + +A cut-off in an LCA is defined as the process for the exclusion of input and output flows associated with unit processes from the product system. Several cut-off criteria exist and are further outlined below. By invoking a cut-off, the assessment can be simplified by excluding processes that will not significantly change the overall conclusions of the study, as long as the intended application is met. + +Cut-offs shall be avoided as far as possible. An alternative to a cut-off is often to model unavailable data based on known data. However, if cut-offs are performed, careful considerations are required. + +[ISO 14044], clause 4.2.3.3 gives general guidance, especially with regard to mass, energy and environmental significance and cumulative considerations. [ISO 14044], clause 4.2.3.3 recommendations shall be followed as closely as possible. + +All cut-off criteria stated by [ISO 14040] and [ISO 14044] are to be considered before cut-off of a certain process, and the process shall be included if significant to at least one criterion. The cut-off criteria include mass, energy and environmental significance. Regarding the environmental significance criteria, a qualitative approach can be accepted, as the estimate of the total impact is + +often not possible at an early stage. A cut-off is only acceptable if allowed by all the above-mentioned criteria. + +NOTE 2 – Environmental significance refers to contribution of for instance greenhouse gas (GHG) emissions. Irrespective of the cut-off method applied, the accumulated effects need careful consideration, to prevent the sum of cut-offs exceeding the targeted share of the total impact which is acceptable for cut-off. + +As a basis for a cut-off, either modelled, secondary or primary data can be used. + +The cut-off is strongly connected to clause 7.2.3 about system boundaries, as a system boundary setting can be seen as a qualitative cut-off. Cut-off of processes or input/output data within the system boundaries requires careful consideration and should be avoided. + +An alternative to a cut-off is often to model unavailable data based on known data. LCA modelling of an ICT good, network or service involves mandatory, recommended, and optional life cycle stages, unit processes and activities. Clearly, 100% of the environmental impacts of any studied product system are never known a priori. However, the life cycle stages, unit processes and activities of Table 2 together constitute a significant share for typical product systems in ICT LCAs. The intention of this Recommendation is to include all mandatory activities of Table 2. If these activities are not included such cut-offs shall be clearly motivated. + +As the total values of environmental impacts can be difficult to calculate, another alternative cut-off method would be to create a reference value based on important activities and to use this reference value to cut-off processes having a negligible contribution compared to that value. Such an approach is especially appropriate when a limited number of processes or phases of a single aspect of the life cycle, contribute by a disproportionate amount to the overall impact. To establish the reference value, secondary data is considered sufficient. + +Any cut-off made shall be clearly described and documented. Activities, processes and flows that have been cut-off should be included in the sensitivity analysis. + +For practical examples on cut-offs refer to Appendix I. + +#### **7.2.5 Data quality requirements** + +##### **7.2.5.1 General** + +In general, data used should reduce bias and uncertainty as far as practicable by using the best quality data achievable. Also, data that is more specific with respect to time, geography and technology takes precedence over data which is less specific. Consequently, primary data is generally preferred to secondary data. + +NOTE 1 – In some cases, secondary data may have lower uncertainty than primary data available. + +In addition, highly accurate, precise, relevant and up-to-date data is preferred. + +For all data categories the data quality requirements from [ISO 14040] and [ISO 14044], clause 4.2.3.6 shall apply. + +A qualitative description of the data quality and any efforts taken to improve it shall be disclosed while considering the following data quality indicators: + +- Methodological appropriateness and consistency +- Completeness (total LCA level) +- Uncertainty +- Data representativeness +- Data age (timeliness) +- Acquisition method + +- Supplier independence +- Geographical correlation +- Technological correlation +- Cut-off rules (rules of inclusion/exclusion). + +As an example, the level of supplier independence could range from "verified data from independent source" to "unverified information from enterprise interested in the LCA". + +It should be noted that the LCA database might not contain all the necessary data quality attributes or descriptions. In such case, it is the LCA practitioner's responsibility to inquire and obtain the appropriate data quality indicators. + +For further information on the data quality indicators please refer to Appendix VII. + +In the LCA context, data refer to activity data, emission factors and, in some cases, direct emissions. + +In selecting emission factors for use in calculating GHG emissions under this methodology, the following guidance shall be followed: + +Emission factors used should be the most up to date from publicly available sources. Where emission factors are sourced from non-public sources, or are not the most up-to-date ones, a justification for their use shall be provided. See also clause 7.7 of [b-ITU-T L.1440]. + +In addition, distribution and transport losses from electricity generation should be included. + +NOTE 2 – While LCA results that comply with this Recommendation take precedence over the other data, it may at the same time lead to situations where in the reuse of previous studies, the most up-to-date emission factors are not used. + +The specific global warming potential (GWP) values used shall be those taken from the latest UN Intergovernmental Panel on Climate Change (IPCC) reports. For further guidance see Table XI.1. See also clause 7.3.1.2.3 regarding energy mixes. + +##### **7.2.5.2 Specific requirements on data and data sources** + +In general, data age and technological correlation are especially important in LCAs for ICT goods, networks and services due to rapid technology evolution and the growth in network traffic. e.g., for data traffic, up-to-date data shall always be used, e.g., for allocation between services, as data traffic grows considerably year by year. Older data therefore tend to give overestimated results for energy use and related emissions per amount of data. The availability of most recent data may vary from one organization to another. + +For support activities (e.g., ICT manufacturer support activities and operator support activities), primary data shall be used for all individual processes under the financial or operational control of the organization undertaking the LCA, and data shall be representative of the processes for which they are collected. + +When available, data compliant with this Recommendation takes precedence before other secondary data sources. + +The data used in the assessment must be representative and relevant. The LCA practitioner shall transparently describe how these requirements are fulfilled. + +The following requirements (Table 4) on data quality shall apply for the different life cycle stages and unit processes. + +In general, ICT-specific data are required for ICT-specific processes. However, the complexity of the supply chain is acknowledged and a representative approach for data is considered sufficient for most LCA purposes, i.e., the LCA practitioner needs not collect data from all suppliers but can focus on a number of representative suppliers whose data are extrapolated to represent all similar products. + +Moreover, it is acknowledged that LCA practitioners from different parts of the value chain have various possibilities to get hold of primary data. One way to handle this situation is the reuse of published data. (e.g., the operator can refer to previous LCAs of ICT goods but have to ensure that the LCA in question is in compliance with this Recommendation). Likewise, an operator can use previous LCAs for networks but has to ensure that these LCA are in compliance with this Recommendation. Data have to be collected (or modelled) at least one step up in the value chain. For further guidance see Appendix I. + +NOTE – This data could be either primary or secondary. + +**Table 4 – Applicable data types per life cycle stage/unit processes** + +| Tag | Life cycle stage/Process | | Unit process | Type of data | | | +|------|--------------------------------|---------------------------------------------------------|--------------|-----------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------| +| | | | | Goods | Network | Service | +| A | Goods raw material acquisition | | | | | | +| A1 | Raw material extraction | | | Secondary data | Secondary data | Secondary data | +| A2 | Raw material processing | | | Secondary data | Secondary data | Secondary data | +| B | Production | | | | | | +| B1 | ICT goods production | | | | | | +| B1.1 | | Parts production (for further details refer to Annex E) | | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | +| B1.2 | | Assembly | | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | +| B1.3 | | ICT manufacturer support activities | | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | +| B2 | Support goods production | | | | | | +| B2.1 | | Support goods manufacturing | | Primary data or ICT-specific secondary data: amounts, etc.
Secondary data: processes | Primary data or ICT-specific secondary data: amounts, etc.
Secondary data: processes | Primary data or ICT-specific secondary data: amounts, etc.
Secondary data: processes | +| B3 | ICT-specific site construction | | | | | | +| B3.1 | | ICT-specific site construction | | Primary data or ICT-specific secondary data: amounts, etc.
Secondary data: processes | Primary data or ICT-specific secondary data: amounts, etc.
Secondary data: processes | Primary data or ICT-specific secondary data: amounts, etc.
Secondary data: processes | +| C | Use | | | | | | +| C1 | ICT goods use | | | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | + +**Table 4 – Applicable data types per life cycle stage/unit processes** + +| Tag | Life cycle stage/Process | Unit process | Type of data | | | +|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------|-------------------------------------------|---------------------------------------------|---------------------------------------------|---------------------------------------------| +| | | | C2 | Support goods use | | +| C3 | Operator support activities | | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | +| C4 | Service provider support activities | | Not applicable | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | +| D Goods end-of-life treatment | | | | | | +| D1 | Preparation for extended operating lifetime | | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | +| D2 | ICT-specific EoLT | | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | +| D2.1 | | Storage/Disassembly/Dismantling/Shredding | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | +| D2.2 | | Recycling | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | Primary data or ICT-specific secondary data | +| D3 | Other EoLT | | Secondary data | | | +| NOTE 1 – For end-of-life treatment (EoLT), the term ICT-specific should be interpreted as processes that are applicable to relevant end-of-life treatment procedures, which may also be used for other electronic goods.
NOTE 2 – For the unit processes for which secondary data is recommended, primary data may be used if available.
NOTE 3 – In case the impact of ICT-specific data and other data do not differ substantially, other data sources may be acceptable. | | | | | | + +### 7.3 Life cycle inventory (LCI) + +#### 7.3.1 Data collection + +##### 7.3.1.1 General + +For data collection, requirements according to [ISO 14040] clause 5.3.2 and [ISO 14044] clause 4.3.2 shall apply. + +Data shall be collected for all mandatory processes outlined in Table 2. Furthermore, data shall be collected, for each unit process that is included within the system boundary, in accordance with *Annex B* for unit processes listed within Annexes D to F. The collected data, whether measured, calculated or estimated, are utilized to quantify the inputs and outputs of a unit process. + +The major headings under which data may be classified are listed in [ISO 14044], clause 4.3.2.3. + +**Rec. ITU-T L.1410 (11/2024)**     39 + +For specific unit process data, measurements at the operated processes are the preferred option (examples are energy consumption, area for multilayer printed circuit boards, good die area for integrated circuits (ICs), mass of materials, etc.). In practice other data sources are helpful (e.g., for cross-checks) or even necessary (e.g., in the case of missing data). This includes, but is not limited to, process engineering models, process and product specifications and testing reports, legal limits, data of similar processes, and best available technology (BAT) reference documents. + +Before the collection of data can be made, each life cycle stage needs to be refined into items, also referred to as unit processes, which represent the basic physical flows (materials and energy) of the life cycle. For details on applicable unit processes for ICT goods, networks and services, refer to clause 7.2.3 "System boundaries". + +A unit process typically represents a production facility but can also model an office or even a vehicle. Annexes B and G, as well as Appendix II, give more details on modelling of unit processes and applicable inputs and outputs. + +In general, data collected should be as accurate as possible in relation to the purpose of the study, the amount of work needed, etc. In particular, primary data based on measurements are considered as more accurate than secondary data. + +Practically, when working with certain LCA tools and LCI databases, e.g., transport and travel (G1) and energy supplies (G2-G4) could be included in larger data sets, whereas other LCA tools/LCI databases provide transport/energy supply separately. The LCA practitioner should report for which processes transport/energy supplies have been added separately and for which they are "hidden". + +The data collection process should be reviewed during the inventory reporting process. It is recognized that there are various potential sources for errors that are inherent to studies that encompass a large number of sites and volumes of separate data. + +The LCA approaches used to date include process sum and economic input/output tables. Both approaches have advantages and disadvantages. In the case of ICT goods, networks and services, a process sum approach is generally the preferred option for evaluating the environmental load. However, situations exist where the process sum may not be the best approach. This could be the case when the scale and complexity of the material inputs and the dynamic nature of the supply chains, where assessments based only on process sum could narrow the system boundary (due to a lack of available data or the time and resources required to capture it) to such an extent that the results will not fully capture the environmental load. In this case, a hybrid life cycle assessment (LCA) approach may be applied where both process sum, and economic input-output (EIO) are used for the assessment to overcome these barriers. In these cases, the approach used should be fully documented and all assumptions made fully disclosed. + +When data has been collected from public sources, the source shall be referenced. For data that may be significant for the conclusions of the study, details about the relevant data collection process, the time when data were collected, and further information about data quality indicators shall be referenced. If such data do not meet the data quality requirements, this shall be stated. In these cases, the approach used should be fully documented and all assumptions made fully disclosed. + +##### 7.3.1.2 ICT goods + +Data shall be collected at least for the processes marked with "mandatory" in Table 2, unless these are found negligible in accordance with the cut-off rules. + +The use stage of ICT goods can show variations depending on operational conditions and therefore needs special consideration when modelling. + +For LCAs of ICT goods, data from representative suppliers, rather than collection of data from all suppliers in the complex and dynamic supply chain is considered sufficient. + +###### **7.3.1.2.1 Use stage energy consumption of ICT goods** + +From a data quality perspective, the best way to determine the energy consumption of ICT goods during the use stage is, whenever possible, to measure a large number of ICT goods operating in a live network/products in real live operating environments over a long period of time (e.g., a year to capture all aspects of variations in traffic, temperatures, different use behaviour, climate etc.). This is facilitated if network goods are equipped with remotely accessible energy meters. Many network goods are installed in sites with energy meters. + +If obtaining data from such measurements is not technically or economically feasible/available, the second-best alternative would be to estimate energy consumption based on available standards for laboratory measurements of energy consumption. For example, for radio base stations, [b-ETSI TS 102 706] and [b-ITU-T L.1310] apply, for estimation of the energy consumption based on available data measured in a laboratory context. This method will however only give a snapshot of real energy consumption and is considered less accurate. + +The third alternative would be to use estimated or measured energy consumption for a certain traffic profile and user behaviour. In this case, it should be noted that, for many products (especially end-user goods), periods of idling and power off may be significant and are important to consider when modelling the traffic profile/ model the usage profile and shall be included if applicable. + +The network energy consumption is calculated as the sum of all ICT goods and support goods energy consumption values obtained as described above. + +###### **7.3.1.2.2 ICT goods data for other life cycle stages** + +For life cycle stages other than the use stage (use stage is discussed in clause 7.3.1.2.1 above), the best quality data should be used for each stage, meaning primary or secondary data. The used input data needs to be documented and justified by the LCA practitioner, as described in this Recommendation. + +Simplified life cycle assessment includes methods such as life cycle stage ratio profiling and input output analysis. If embodied emissions versus use stage emissions ratio is known, that gives an approximation in the absence of more detailed information. It could also mean component characterization or hardware parameterization applicable to the assessed case. The method adopted for different data sets should be documented. + +It should be noted that simplified assessment methods are not suitable for all purposes. It is LCA practitioner's responsibility to ensure that the used methods can be applied for the intended purpose. + +###### **7.3.1.2.3 Consideration of energy mixes** + +When calculating the potential environmental impact, the LCA practitioner is encouraged to use the most accurate data for the energy mix that is applicable to the ICT goods under assessment. In particular, the use stage shall use the applicable electricity mix to calculate the potential environmental impact from the use stage more exactly. + +When known, market-based data (emissions from electricity that a company have purposefully chosen, e.g., derived from contractual instruments) are recommended for most accurate results. Location-based data (average grid emission factor data for the given locality or region) can be used when market-based data is not available. Global average data is not preferred as it provides the least accurate results. + +NOTE – The electricity mix ought to closely reflect the intended use place for the goods. For further guidance see Appendix V. + +For other life cycle stages, representative energy mixes are preferred in accordance with the goal and scope of the assessment. + +It is observed that different emission factors for electricity may or may not consider the energy supply and distribution. As complete emission factors as possible should be used and the comprehensiveness of those should be transparently reported. + +See clause 7.2.5.1 for further guidance on emission factors. + +Annex D and Appendix I also provide guidance on how to consider energy mix related matters. + +###### **7.3.1.2.4 Handling of LCI results for electricity and energy** + +During the assessment and when reporting energy consumption, the following inputs should be considered: + +- Electricity (with use stage separated from the other stages) +- Other forms of delivered energies (for example district heating and cooling) +- Fuels (typically indicates the fuels are combusted on-site or in a vehicle connected to the site). + +When reporting both total primary energy and electricity, it is important to note that these two cannot be summarized because electricity is contributing to the total primary energy. + +NOTE – Primary energy usage, assessed with methods such as cumulative energy demand (CED), is to be reported as an LCI result appropriately, according to Table L.9. + +Annex G contain important life cycle inventory (LCI) elementary flows (emissions and resources) and fuels that shall be considered in LCA studies for ICT. + +##### **7.3.1.3 ICT networks** + +As ICT networks consist of ICT goods, the principles in clause 7.3.1.2 shall also apply for data collection of ICT networks. + +Particularly the network energy consumption is calculated as the sum of all ICT goods and support goods energy consumption values obtained as described above. + +Often network LCAs are very challenging and may need to rely on previous LCA results for the different ICT goods. If so, data from studies that are compliant with this Recommendation takes precedence if available. The data used in the assessment must be representative and relevant, in alignment with data quality requirements described in clause 7.2.5. The LCA practitioner shall transparently describe how these requirements are fulfilled. + +##### **7.3.1.4 ICT services** + +Often service LCAs are very challenging and may need to rely on previous LCA results for the different ICT goods. If so, data from studies that are compliant with this standard takes precedence if available. Use time, goods type, data traffic and network access type give important statistical data that needs to be collected in order to quantify the use of ICT systems. + +#### **7.3.2 Data calculation** + +##### **7.3.2.1 General** + +The general requirements for data calculations in [ISO 14040] and [ISO 14044] shall be applied. + +NOTE 1 – [ISO 14044], clause 4.3.3 applies as well. + +Several operational steps are needed for data calculation. These are described in [ISO 14044], clauses 4.3.3.2 to 4.3.3.4 and 4.3.4 and [b-EUR 24708 EN], clause 7.10. All calculation procedures shall be explicitly documented and the assumptions made shall be clearly stated and explained. The same calculation procedures shall be consistently applied throughout the study. Practically, when working with certain LCA tools and LCI databases, calculation procedures could be included in larger data sets, whereas other LCA tools/LCI databases provide each procedure separately. + +NOTE 2 – It may be possible to derive the calculation procedures from the LCI databases, e.g., for raw materials. + +A check on data validity shall be conducted during the process of data collection to confirm that the data quality requirements for the intended application have been fulfilled. + +Validation involves establishing, e.g., mass balances. + +##### **7.3.2.2 ICT goods** + +ICT goods consist of hardware and software. For both hardware and software, design, development, production, procurement and operation and maintenance activities are of interest and should be considered in accordance with clause 7.2.3, "System boundaries". + +In terms of life cycle stages, most of these activities can be seen as support activities as detailed in clause 7.2.3, and the associated environmental impact emerges from the use of buildings, office goods and consumables, from travel and transport, and from the generation of waste. All of these should be assessed as fully as possible, but it is not necessary to make a distinction between them, i.e., the total energy consumption of the office of the designers should be allocated between the designers, but it is not necessary to make a distinction between energy for heating and energy for office goods associated with each designer. + +For applicable allocation rules, refer to clause 7.3.3, "Allocation procedure". + +Similar conditions shall also apply for software being procured from a supplier and integrated into the product. + +For example, when assessing the environmental impact coming from the use stage of a base station (BS), the assessment may take into account power-saving opportunities resulting from low or empty load periods during which the BS may turn off part or all of its transmission/reception; in this case, the spatio-temporal distribution of traffic load may be based on actual or modelled data. + +##### **7.3.2.3 ICT networks** + +It is necessary to consider the functional unit of an ICT network when performing data calculation. The following data calculation method should be performed in order to take into account the functional unit of the assessed ICT network. + +First, the functional unit is established in accordance with clause 7.2.2 and then the corresponding environmental load is estimated. Since each ICT network is continuously evolving, the life cycle of an ICT network cannot be generalized with terms such as "from cradle to grave". Instead, each ICT good, which is part of the considered ICT network, is regarded as a product system and is assessed separately. + +The total environmental load of each ICT good should be divided by the operating lifetime of each ICT good in order to calculate the annual environmental load of each considered ICT good. If the actual operating lifetime is not available, a statistically, economically, or legally defined lifetime may be used instead. See clause 7.1.5 for details. + +In the next step, the annual environmental loads of the ICT goods belonging to the considered ICT network are added in order to calculate the total annual ICT network environmental load. + +For instance, for a theoretical mobile access network composed of 1 000 identical base stations and 10 identical radio network controllers, the annual environmental load of this mobile access network is calculated as 1 000 times the individual annual environmental load of one base station plus 10 times the individual annual environmental load of the radio network controller. + +For the following described kinds of ICT networks, the environmental load of the use stage should be calculated as follows: + +For the assessment of fixed access networks, a constant value is generally applicable for the use stage energy-related environmental load (e.g., per subscriber), as the goods are connected to the access network whether or not the subscriber is using it. However, when power-saving features are used, a fixed value may not be applicable. + +For the mobile access network, the assessment needs to consider the temporal variation in both traffic load and different power save modes. Additionally, different BSs experience different overall loads, which also needs to be considered in the impact assessment. For further details refer to clause 7.3.2.2. + +##### **7.3.2.4 ICT services** + +Data calculation for services is to a large extent related to the allocation of an appropriate amount of network data to the targeted service. For further details refer to clause 7.3.3. + +#### **7.3.3 Allocation procedure/Allocation of data** + +##### **7.3.3.1 General** + +NOTE – [ISO 14044], clauses 4.3.3 and 4.3.4 shall also apply. + +During the boundary setting phase, LCA practitioners may identify processes that have inputs and/or outputs that are shared between different product systems. In these situations, data collected on emissions needs to be shared between the studied ICT goods, networks and services product system and the other products systems. This apportioning is referred to as allocation, and is often considered one of the most challenging issues in LCAs. This clause provides requirements and guidance to help LCA practitioners to choose the most appropriate method to address this allocation issue. + +The same allocation method shall be used for all environmental loads for all products from a common process. + +The study shall identify the processes shared with other product systems and deal with them according to the stepwise procedure presented below. + +Step 1: Wherever possible, allocation should be avoided by dividing the unit process to be allocated into two or more subprocesses and collecting the input and output data related to these subprocesses, or expanding the product system to include the additional functions related to the co-products. + +Step 2: Where allocation cannot be avoided, the inputs and outputs of the system should be partitioned based on the underlying physical relationships between them (e.g., mass). + +Step 3: If step 2 is not feasible, the inputs should be allocated between the products and functions reflecting other relationships between them. For example, input and output data might be allocated between co-products in proportion to the economic value of each product (e.g., market value of the scrap material or recycled material in relation to the market value of primary material). + +If alternative allocation processes are applied, the different options should be tested in the sensitivity analysis. More specific guidance is given in the following clauses. + +##### **7.3.3.2 Allocation rules for generic processes** + +Data for generic processes (G1 to G7) shall be allocated as a whole (i.e., for the full life cycle for the generic process) to the associated life cycle stage of the product system. + +However, all raw material acquisition (G5) shall be allocated to the life cycle stage Goods raw material acquisition (A). + +##### **7.3.3.3 Allocation rules for allocation of support activities between projects/product systems** + +Data for relevant parts of the organization/operation shall be allocated to the relevant part of the product system life cycle. If no detailed information on organization/operation is available, the allocation shall be based on organizational or economic data. + +NOTE – Previous studies indicate that results may be sensitive to different allocation methods. + +##### **7.3.3.4 Allocation rules for facility data** + +Facility data for production facilities shall preferably be allocated to product systems based on relevant physical data (i.e., area for printed circuit boards, good die area for ICs, mass for other components according to Table E.1). If information regarding physical parameters is insufficient, economic allocation may be used. + +NOTE – Other relevant physical data are indicated in Annex E. + +For software design the "facility" is usually an office, in which case the allocation rules in clause 7.3.3.3 shall apply. + +##### **7.3.3.5 Allocation rules for transport** + +Transport should be allocated based on chargeable mass or volume, whichever limits the transport capacity. Empty return trips need also to be considered, if applicable. + +##### **7.3.3.6 Allocation rules for recycling** + +The impacts of raw material recycling (G7) should be allocated between life cycles, in practice between raw material acquisition (A1-A2) and EoLT (D), according to the following principles: + +All elementary flows and consequently all environmental impacts of landfill shall be fully allocated to the life cycle that puts the material in a landfill, or other types of residual waste storage. + +The material resource depletion impact and related elementary flow shall be fully allocated to the life cycle that depletes the material resource (e.g., putting the material in landfill). Consequently, if the assessed ICT product system is wasting materials it shall carry this burden fully and could not share it with other product systems. + +NOTE 1 – See Appendix I for example of fulfilment. + +The 100/0 allocation method should be used for calculating the primary raw material acquisition impact. + +The 50/50 allocation method should be applied when possible to allocate both the use of recycled input material in the raw material acquisition stage and the recycling of materials in the EoLT stage. United States Geological Survey (USGS) yearly mineral report can be used to estimate the ratio of recycled material content for input material if primary data are not accessible. In reuse/refurbishment scenarios, the LCA practitioner needs to clearly declare how the allocation of raw materials has been handled in the assessment. + +NOTE 2 – US geological survey USGS available (). + +If available input LCI data does not distinguish between primary raw material acquisition and raw material recycling, the 100/0 method can be used as a fall-back alternative (see examples in Appendix VI). + +##### **7.3.3.7 ICT goods** + +Allocation principles stated in clause 7.3.3.1 shall apply to allocations for ICT. + +##### **7.3.3.8 ICT networks** + +Allocation principles stated in clause 7.3.3.1 shall apply to allocations for ICT networks. + +To calculate the total impact of a network, a top-down approach is recommended, i.e., it is in most cases more practicable to assess the overall energy consumption of a network than to assess the energy consumption per service and add it up to a total value. + +Support activities and, when applicable, support goods which is shared between several nodes or all network goods need not be allocated to the different ICT goods but can be presented without being distributed. + +End-user goods (e.g., PCs, smart phones) which access more than one ICT network (e.g., 3G, WLAN) shall be allocated to these ICT networks based on use time. The assumptions regarding use time for access to different ICT networks and offline work shall be described and motivated. + +NOTE – Preferably usage studies can be used as a source but if such studies are not available estimates need to be done. + +Impact from shared network resources (e.g., transmission goods, core nodes and data centres) shall be allocated to an access network based on data traffic. The assumptions regarding data traffic shall be described and motivated. + +##### 7.3.3.9 ICT services + +The allocation procedure for ICT services should comply with the allocation procedure used for the ICT networks and goods supporting these ICT services. + +If an ICT good is shared among several ICT services, the environmental load should be allocated according to the estimated usage of these various ICT services, as illustrated in Figure 13. + +| | | +|--------------|-----------| +| ICT services | Service A | +| ICT networks | | +| ICT goods | | + +L.1410(15)\_F13 + +**Figure 13 – Allocation procedure for ICT services** + +The environmental load of an ICT service should then be calculated as follows: + +First, the ICT networks, which are allowing the service to be operated, and the additional ICT goods, which are not part of networks and which are used by the service, should be identified. Then, the environmental load of each ICT network supporting the service and each additional ICT good using the service, should be assessed. After that, the impact from each ICT goods used should be allocated to the service based on either estimated or measured use time or amount of data traffic. The impact from each ICT network supporting the service should be allocated to the service based on access use time or data traffic. + +More specifically, in alignment with clause 7.3.3.8, the following allocation principle of ICT network data to an ICT service shall be used: + +Data for end-user goods: + +- to be allocated based on active use time of the ICT service. + +NOTE 1 – In certain cases the above rule provides unreasonable results and other allocation bases may then be more appropriate. + +Data for customer-premises equipment (CPE): + +- to be allocated based on active use time of the service or data traffic or data rate/allocated bandwidth. + +Data for access networks, control and core nodes and operator activities: + +- to be allocated based on active use time of the service unless there is a substantial dependency between data traffic and energy consumption. Thus, access/active use time is preferred for circuit-switched networks and data traffic is preferred for packet-switched networks. Data traffic is also preferred for e.g., mobile access networks as mobile access networks show a + +large dependency between data traffic and energy consumption and need a traffic model that takes data traffic into account. However, also in this case the load independent part of the energy consumption can be allocated based on active use time. + +Data for transport goods: + +- to be allocated based on data traffic. + +Data for data centres and service provider activities: + +- The data centre(s) where the ICT service is operated as well as the service provider activities shall be allocated based on the number of subscriptions and service users or amount of data/transactions. + +It should be noted that the assessment of the impact of ICT services can be a complex exercise, which may require collecting large volumes of data just as a prerequisite when assessing a single service. The LCA practitioner needs to be careful because this may introduce problems regarding the availability of data. + +NOTE 2 – Average figures for energy use and related emissions per amount of data reflect average traffic. Thus, for low and high data traffic scenarios, average figures may give unrealistic results and results that do not reflect the actual impact of the service data traffic. + +The following example shows the estimation of CO2 emissions of PCs included in customer premises when the environmental load item is CO2 emissions: + +$$\frac{[\text{Annual environmental load per PC [kg-CO}_2\text{/(unit}\cdot\text{year)}] \times [\text{Number of units used (unit)}] \times [\text{Operating hours of the ICT service (hours/service)}] \times [\text{Frequency of use of the ICT service (times/year)}]}{[\text{Total operation time of the PC (hours/year)}]}$$ + +## 8 Life cycle impact assessment (LCIA) + +### 8.1 Introduction to LCIA + +The life cycle impact assessment (LCIA) aims to describe and assess the impact of the environmental loads quantified in the inventory analysis. LCIA is a stepwise aggregation of the information given by the life cycle inventory (LCI) results. + +The LCIA aims to evaluate the significance of potential environmental impacts using the LCI results. In general, this process involves associating inventory data with specific environmental impact categories and category indicators, thereby attempting to understand these impacts. + +For LCIA, the requirements, according to clause 4.4 in [ISO 14044] and clauses 6.7 and 8 in [b-EUR 24708 EN], shall apply. + +### 8.2 Impact categories + +In general, a single impact category alone cannot solely evaluate the environmental impact of a product. Instead, multiple impact categories are needed. + +ISO states that the selection of impact categories shall reflect a comprehensive set of environmental issues related to the product system being studied, taking the goal and scope into consideration. + +Of the various impact categories, an important impact category for ICT goods, networks and services is climate change (global warming), which results, to a large extent, from energy consumption. + +In the LCA it shall be ensured that the inventory elementary flows (see Annex G) are correctly linked with appropriate LCIA characterization factors. + +The link to end-point categories (e.g., infectious diseases and plant damage) is optional. + +The midpoint category 'climate change' is mandatory. + +For climate change, the most recent global warming characterization factors from the Intergovernmental Panel on Climate Change (IPPC) for each GHG shall be used and the timeframe should be 100 years. + +For other impact categories, there is no methodological consensus in the LCA community. Thus, the LCA practitioner shall decide which impact categories to consider and how to calculate them, based on the studied ICT product system and purpose of the LCA study. In general, a broad approach in terms of environmental impacts is recommended to give a broad understanding of the environmental impact of the studied ICT product system. + +All impact categories and category indicators included shall be disclosed (Table L.10) and justified. + +Table 5 shows examples of impact categories. + +**Table 5 – Examples of environmental impact categories and indicators** + +| Midpoint impact categories | Midpoint category indicator | End-point impact Categories | End-point category indicator | Recommended level (Midpoint – End-point) | Reference | +|---------------------------------------------------|---------------------------------------------------------------------------------------------------|--------------------------------|-----------------------------------------------------------------------------|------------------------------------------|-----------------------| +| Climate change (CC) (mandatory) | Mass CO 2 equivalent (Infrared forcing as GWP100-year) | Infectious diseases, Land loss | Disability adjusted life years (DALY), Extinction of species, Resource cost | I – Interim | IPCC [b-IPCC] | +| Ozone depletion (OD) | Mass CFC-11 equivalent (see Note 3) (ultraviolet B (UV-B) radiation as Ozone Depletion Potential) | Plant damage, Skin cancer | Net primary production, DALY | I – Interim | ILCD [b-EUR 24586 EN] | +| Human toxicity cancer effects (HTC) | Comparative Toxic Unit for humans (CTUh) (Concentration at human uptake level) | Cancer | DALY | II/III – II/interim | [b-EUR 24586 EN] | +| Human toxicity non-cancer effects (HTNC) | Comparative toxic unit for humans (CTUh) (Concentration at human uptake level) | Memory loss | DALY | II/III – Interim | [b-EUR 24586 EN] | +| Respiratory inorganics/Particulate matter (RI/PM) | Mass PM 2.5 equivalent (see Note 4) | Bronchitis, Asthma attacks | DALY | II/III – II (see Note 5) | [b-EUR 24586 EN] | +| Ionizing radiation human health (IRH) | Mass U 235 equivalent | Cancer | DALY | II – Interim | [b-EUR 24586 EN] | + +**Table 5 – Examples of environmental impact categories and indicators** + +| Midpoint impact categories | Midpoint category indicator | End-point impact Categories | End-point category indicator | Recommended level (Midpoint – End-point) | Reference | +|--------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------|------------------------------|--------------------------------------|------------------------------------------|------------------| +| Ionizing radiation ecosystems (IRE) | Comparative toxic unit for ecosystems (CTUe)×volume×time | | | Interim – No methods recommended | | +| Ionizing radiation ecosystems (IRE) | Comparative toxic unit for ecosystems (CTUe)×volume×time | | | Interim – No methods recommended | | +| Eutrophication aquatic (EA) | Freshwater:
Mass P-equivalents
Marine water:
Mass N-equivalents | Fish population | Resource cost | II – Interim | [b-EUR 24586 EN] | +| Eutrophication terrestrial (ET) | Mole N-equivalents | Herbivore population | Resource cost, Extinction of species | II – No methods recommended | [b-EUR 24586 EN] | +| Photochemical ozone formation (POF) | Mass C 2 H 4 -equivalents (Tropospheric O 3 concentration increase) | Asthma, Plant damage | DALY, Net primary production | II – II | [b-EUR 24586 EN] | +| Acidification (A) | Mole H + -equivalent | Plant damage | Net primary production | II – Interim | [b-EUR 24586 EN] | +| Ecotoxicity freshwater (ETFW), (see Note 6) | Comparative toxic unit for ecosystems (CTUe)×volume×time (Concentration at aquatic ecosystem species uptake level) | Aquatic ecosystem population | Extinction of species | II/III – No methods recommended | [b-EUR 24586 EN] | +| Land use (LU) | Mass deficit of soil organic matter | Land loss | Extinction of species, resource cost | III – Interim | [b-EUR 24586 EN] | +| Resource depletion water (RDW) | Water amount as water use related to local scarcity of water | User cost | Resource cost | III – No methods recommended | [b-EUR 24586 EN] | +| Resource depletion mineral fossil (RDMR), (see Note 7) | Minerals as mass Sb-equivalent and fossil fuels as megajoule (MJ) (Resource amount as scarcity) | User cost | Resource cost | II – Interim | [b-EUR 24586 EN] | + +**Table 5 – Examples of environmental impact categories and indicators** + +| Midpoint impact categories | Midpoint category indicator | End-point impact Categories | End-point category indicator | Recommended level (Midpoint – End-point) | Reference | +|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------|-----------------------------|------------------------------|------------------------------------------|-----------| +|

NOTE 1 – The midpoint impact categories are suggested by the international reference life cycle data system (ILCD) [b-EUR 24586 EN] and product environmental footprint (PEF) [b-EC common methods]. For other impact categories beyond 'climate change', the scientists are still debating on the suitable methodology and the category indicators referred in this table may change in the future. Especially Land use methodology is still very open. Refer to international reference life cycle data system (ILCD) and other documents for up-to-date methodology to use for each impact category.

NOTE 2 – At the time of publication of this Recommendation, the recommended levels are taken from the most recent ILCD guideline [b-EUR 25167 EN]. Refer to ILCD guideline for the most up-to-date information and the explanation of the different recommended levels.

NOTE 3 – CFC-11 = Trichlorofluoromethane, also called freon-11 or R-11, is a chlorofluorocarbon.

NOTE 4 – PM2,5 = Particulate matter with a diameter of 2,5 µm or less.

NOTE 5 – These recommended levels are taken from ILCD guideline [b-EUR 25167 EN] clause 3.3. The same guideline has different recommended levels for respiratory inorganics/Particulate matter in clause 1.1 [b-EUR 25167 EN], where the levels are I – I/II.

NOTE 6 – There are currently no recommended methods for ecotoxicity, marine water and terrestrial.

NOTE 7 – There are currently no recommended methods for resource depletion, renewables.

| | | | | | + +## 9 Life cycle interpretation + +NOTE – [ISO 14044], clause 4.5 also applies. + +### 9.1 General + +Interpretation is the phase of LCA in which the findings from the life cycle inventory (LCI) analysis and the life cycle impact assessment (LCIA) are considered together. In the life cycle interpretation, the results of the LCA are evaluated to answer questions raised in the goal definition (clause 7.2). The steps of the interpretation shall ensure the robustness of the conclusions from the LCA. + +During the iterative steps of the LCA, the interpretation phase serves to improve the LCI model. + +In the end, the interpretation relates to the intended applications of the LCI/LCA study and is used to draw conclusions, identify limitations and produce recommendations. + +The life cycle interpretation shall include an analysis of the results and the consistency, a completeness check, and a sensitivity check of the significant issues and methodological choices to understand the uncertainty of the results. + +The challenge of the completeness check is to overcome the paradox of evaluating the degree of completeness of the product system when not knowing 100% of its environmental impacts. + +If two or more ICT goods, networks or services LCA results do not differ significantly, there is a risk of erroneous interpretations. For example, there is a risk of inappropriately claiming equality or superiority of one or several compared alternatives, based on poor data quality that results in underestimations/overestimations of differences. This risk could lead to incorrect general conclusions and recommendations. + +NOTE – The significance is determined for instance by the magnitude in difference, modelling assumptions, and LCA tool calculation algorithm. + +### 9.2 Uncertainty analysis + +The uncertainty of LCA study results shall be assessed in accordance with [ISO 14044] to the extent needed to understand the study results. Also, the sources of uncertainty and methodological choices made shall be assessed and disclosed. Appendix VIII provides more information regarding uncertainty categories and important uncertainty sources for the different life cycle stages of ICT goods, networks and services. Appendix IX provides more information regarding opportunities and limitations in the use of LCA for ICT goods, networks and services. + +### 9.3 Sensitivity analysis + +The results of the LCI or LCIA phases shall be interpreted according to the goal and scope of the study. The interpretation shall include a sensitivity check of the significant inputs, outputs and methodological choices, and defined use scenarios, in order to understand the uncertainty of the results. Especially when modelled data are used, different scenarios should be assessed to establish a range of potential outcomes to limit the uncertainty. For requirements on sensitivity analysis refers to [ISO 14044], clauses 4.3.3.4 and 4.5.3.3. + +## 10 Reporting + +### 10.1 General + +Reporting is essential to ensure accountability and effective engagement with stakeholders. This clause summarizes the various reporting requirements and identifies additional reporting considerations to establish a credible reporting framework and enable users of reported data to make informed decisions. + +The reporting of ICT product systems shall comply with the reporting rules defined by [ISO 14040] and [ISO 14044]. In the case of reporting, a public GHG inventory report, the key accounting principles (relevance, accuracy, completeness, consistency, and transparency) shall be met. + +For LCA results to be credible, a transparent approach in the reporting of how the data has been collected is recommended to an extent that it does not conflict with confidentiality considerations. + +In addition to the reporting obligations outlined by [ISO 14040] and [ISO 14044], the report shall include the following information: + +- Contact information; +- Studied goods, networks and services product system name and description; +- Type of inventory (i.e., final product cradle-to-grave or intermediate product cradle-to-gate inventory); +- Goals of the study. + +The reporting of results shall include: + +- Total GHG emissions reported as amount of carbon dioxide equivalent (CO2e) per functional unit for ICT good, networks and services assessed; +- Percentage for each life cycle stage contributing to the total results; +- Electricity (with use stage separated from the other stages); +- Primary energy; +- Fuels; +- Value and sources of emission factors, clearly indicating their use, for CO2 and CO2e, and global warming potential (GWP) metric used for generic processes G1 to G4, described in Annex D (for further details see Annex L); +- Other data, justifications and explanations as stated throughout this report. + +NOTE – primary energy and electricity cannot be summarized, because electricity is contributing to the total primary energy. + +The emission factors used shall be clearly stated. The source and the corresponding year shall be stated. + +In the case of emission factors for grid electricity, the source and the location (specific, country, global average) shall be specified. + +Where emission factors are sourced from non-public sources or are not the most recent, a justification for their use shall be provided. + +Generally, in addition to the rules outlined in this clause, what is stated in Annex L shall be followed for reporting of studies claiming compliance with this Recommendation. + +The report shall contain a compliance statement, indicating whether the LCA fully complies with this Recommendation (in case of *full compliance*) or whether the LCA partially complies with this Recommendation, with exceptions transparently listed and justified (*partial compliance*). See clause 6.2 for details. + +The extent to which *support activities* and other optional/recommended activities are excluded from different parts of the life cycle shall be clearly described and, for recommended activities, also motivated in the study report. + +The goal of standardizing reporting is to improve transparency and provide the reader with a clear basis for interpretation of results. + +Optional data, diagrams, statements, etc. may be added to the report, depending on the scope and purpose of the LCA. + +For each product system (including *ICT goods, network and service*) the following aspects, which are particularly important for ICT solutions, shall be transparently justified and described in accordance with the principles defined in this clause: + +Operating lifetime: All lifetime assumptions shall be stated and justified. + +- Cut-off: Any cut-off made shall be clearly stated and justified. +- Allocations: Basis for allocations made shall be described, especially for recycling, use of recycled materials, distribution of facility data and support activities. +- Data sources: Data sources (i.e., primary/secondary) shall be clearly stated, and deviations from Table 2 shall be justified. +- System boundaries: In case of cradle-to-gate system boundaries, the LCA practitioner shall clearly state the definition of 'gate' used in the assessment. Default definition is given in clause 3.1, but alternative definitions may be used depending on the scope and goal of the assessment. + +For each product system (including ICT goods, networks and services), an additional diagram shall be presented when optional activities in Table 2 are included. For instance, one diagram may represent only the mandatory activities/processes, while another illustrates both mandatory and optional activities for transparent reporting. + +### 10.2 ICT goods + +#### 10.2.1 Total results + +For each impact category studied, diagrams corresponding to Figures 14a and 14b shall be reported for the corresponding category indicator result. + +Due to the importance of operating lifetime to results, information regarding this element shall always be included in the diagram, along with other basic modelling statements, such as the total result for + +the indicator, LCA study year operating lifetime, etc. as shown below. Figure 14a provides an example of the results corresponding to the 'mandatory' section of Table 2, whereas Figure 14b illustrates an example of the results for the 'mandatory/recommended/optional' section of Table 2. + +NOTE 1 – Other diagram styles are allowed, provided that the content is equivalent that of Figures 14a and 14b. + +NOTE 2 – It is recognized that, due to limitations in LCA tools/LCI databases, achieving a full split between life cycle stages (A-D) may be challenging. + +![Figure 14a: Bar chart showing environmental impact categories (Raw material acquisition, Production, Use, EoLT) for global warming potential (GWP100) (CO2e).](509a054727400bc6d424bb2a559b8cfc_img.jpg) + +Figure 14a is a bar chart showing the environmental impact categories for global warming potential (GWP100) (CO2e). The y-axis represents kg CO2e/year, ranging from -20 to 80. The x-axis shows four categories: Raw material acquisition (A)\*, Production (B)\*, Use (C), and EoLT (D)\*. The bars are colored red, yellow, blue, and green respectively. The 'Use (C)' category has the highest impact at approximately 70 kg CO2e/year. The 'Raw material acquisition (A)\*' category is at approximately 15 kg CO2e/year. The 'Production (B)\*' category is at approximately 25 kg CO2e/year. The 'EoLT (D)\*' category is at approximately 5 kg CO2e/year. + +Legend: + +- Total result: 2e/year> +- Study year: <20##> +- Operating lifetime: <# years> +- Production: + - Assembly location: + - Transport: +- Use: + - Use location: + +L.1410(14)\_F14a + +Figure 14a: Bar chart showing environmental impact categories (Raw material acquisition, Production, Use, EoLT) for global warming potential (GWP100) (CO2e). + +\*This value has been divided by operating lifetime to produce an annual value + +**Figure 14a – Environmental impact category indicator result diagram – example for Mandatory processes/activities (diagram for global warming potential (GWP100) (CO2e))** + +Figure 14a shall be accompanied by the disclaimer "This LCA result cannot be compared to the result of another LCA unless all assumptions and modelling choices are equal". See further explanation in the scope and clause 6.3. + +Figure 14b shall be presented whenever optional activities/processes from Table 2 have been included in the studied product system. + +![Figure 14b: Bar chart showing environmental impact categories (Raw Material Acquisition, Production, Use, EoLT) for global warming potential (GWP100) (CO2e).](de5b0e2754b83541a8429dbb036d1a0e_img.jpg) + +Figure 14b is a bar chart showing the environmental impact categories for global warming potential (GWP100) (CO2e). The y-axis represents kg CO2e/year, ranging from -50 to 150. The x-axis shows four categories: Raw Material Acquisition (A)\*, Production (B)\*, Use (C), and EoLT (D)\*. The bars are colored white, light grey, dark grey, and green respectively. The 'Use (C)' category has the highest impact at approximately 140 kg CO2e/year. The 'Production (B)\*' category is at approximately 40 kg CO2e/year. The 'Raw Material Acquisition (A)\*' category is at approximately 20 kg CO2e/year. The 'EoLT (D)\*' category is at approximately 10 kg CO2e/year. + +Legend: + +- Total result: 2e/year> +- Study year: <20##> +- Operating lifetime: <# years> +- Production: + - Assembly location: + - Transports: +- Use: + - Use location: + - Transports: + - Support activities: +- Infrastructure: + +L.1410(14)\_F14b + +Figure 14b: Bar chart showing environmental impact categories (Raw Material Acquisition, Production, Use, EoLT) for global warming potential (GWP100) (CO2e). + +\*this value has been divided by operating lifetime to produce an annual value + +**Figure 14b – Environmental impact category indicator result diagram – example for Mandatory/Recommended/Optional processes/activities (diagram for global warming potential (GWP100) (CO2e))** + +For transport, the total result, including all transport throughout the life cycle, shall be stated in the immediate proximity to the diagram (Figures 14a and 14b), in accordance with Table L.4. If used data sets do not report all transport used separately, any missing transport shall be listed and justified. + +Optionally, a diagram showing transport and other subunit processes within each life cycle stage should also be reported (Figure 15). Such transparency is encouraged. + +![Figure 15: Bar chart showing environmental impact category indicator result distribution between subunit processes within each life cycle stage. The Y-axis represents kg CO2e/year from -10 to 80. The X-axis shows four life cycle stages: Raw material acquisition (A)*, Production (B)*, Use (C), and EoLT (D)*. The legend identifies subunit processes: Raw material extraction, Raw material processing, Transport, Parts production, Assembly, ICT equipment use, ICT-specific EoLT, Other EoLT, Transport, and Metal recycling.](2865fd60541ac34a704bc9e7af1041f7_img.jpg) + +| Life Cycle Stage | Subunit Process | Value (kg CO 2 e/year) | +|-------------------------------|-------------------------|-----------------------------------| +| Raw material acquisition (A)* | Raw material extraction | ~5 | +| | Raw material processing | ~6 | +| Production (B)* | Transport | ~2 | +| | Parts production | ~15 | +| | Assembly | ~3 | +| | Transport | ~6 | +| Use (C) | ICT equipment use | ~70 | +| EoLT (D)* | ICT-specific EoLT | ~2 | +| | Metal recycling | ~1 | + +Figure 15: Bar chart showing environmental impact category indicator result distribution between subunit processes within each life cycle stage. The Y-axis represents kg CO2e/year from -10 to 80. The X-axis shows four life cycle stages: Raw material acquisition (A)\*, Production (B)\*, Use (C), and EoLT (D)\*. The legend identifies subunit processes: Raw material extraction, Raw material processing, Transport, Parts production, Assembly, ICT equipment use, ICT-specific EoLT, Other EoLT, Transport, and Metal recycling. + +\*This value has been divided by operating lifetime to produce an annual value + +**Figure 15 – Environmental impact category indicator result: distribution between subunit processes within each life cycle stage** + +Figure 15 shall be accompanied by the disclaimer "This LCA result cannot be compared to the result of another LCA unless all assumptions and modelling choices are equal". See further explanation in the scope and clause 6.3. + +A diagram summarizing distribution of selected environmental impact category indicators between life cycle stages shall be prepared together with absolute figures as shown in the Annex L (Table L.10). The diagram may be presented according to Figure 16. + +![Figure 16: Horizontal stacked bar chart showing environmental impact category indicators overview for ICT goods. The Y-axis lists 15 impact categories (RDMR, RDW, LU, ETFW, A, POF, ET, EA, IRE, IRH, RI/PM, HTNC, HTC, OD, CC) with their total scores. The X-axis shows the percentage distribution from 0% to 100%. The legend identifies life cycle stages: Raw material acquisition (A)* and EoLT (D)* (white), Production (B)* (grey), and Use (C) (black).](70546cb98239089866510133c7fbc169_img.jpg) + +| Impact Category | Raw material acquisition (A)* and EoLT (D)* (%) | Production (B)* (%) | Use (C) (%) | +|--------------------------|-------------------------------------------------|---------------------|-------------| +| RDMR [unit] Total score | ~80 | ~10 | ~10 | +| RDW [unit] Total score | ~35 | ~30 | ~35 | +| LU [unit] Total score | ~90 | ~5 | ~5 | +| ETFW [unit] Total score | ~30 | ~40 | ~30 | +| A [unit] Total score | ~10 | ~10 | ~80 | +| POF [unit] Total score | ~5 | ~5 | ~90 | +| ET [unit] Total score | ~20 | ~10 | ~70 | +| EA [unit] Total score | ~15 | ~5 | ~80 | +| IRE [unit] Total score | ~10 | ~5 | ~85 | +| IRH [unit] Total score | ~5 | ~5 | ~90 | +| RI/PM [unit] Total score | ~5 | ~50 | ~45 | +| HTNC [unit] Total score | ~20 | ~25 | ~55 | +| HTC [unit] Total score | ~10 | ~20 | ~70 | +| OD [unit] Total score | ~5 | ~10 | ~85 | +| CC [unit] Total score | ~5 | ~10 | ~85 | + +Figure 16: Horizontal stacked bar chart showing environmental impact category indicators overview for ICT goods. The Y-axis lists 15 impact categories (RDMR, RDW, LU, ETFW, A, POF, ET, EA, IRE, IRH, RI/PM, HTNC, HTC, OD, CC) with their total scores. The X-axis shows the percentage distribution from 0% to 100%. The legend identifies life cycle stages: Raw material acquisition (A)\* and EoLT (D)\* (white), Production (B)\* (grey), and Use (C) (black). + +**Figure 16 – Environmental impact category indicators overview for ICT goods** + +Figure 16 shall be accompanied by the disclaimer "This LCA result cannot be compared to the result of another LCA unless all assumptions and modelling choices are equal". See further explanation in the scope and clause 6.3. + +#### **10.2.2 System boundaries** + +##### **10.2.2.1 Life cycle stages, unit processes and generic processes** + +Any deviation from Table 2 and clause 7.2.3 with respect to mandatory life cycle stages/unit processes shall be clearly stated and justified. + +Also, the handling of optional stages/activities shall be clearly reported, including the electricity mix applied, and handling of support activities and transport. + +For an appropriate reporting format refer to Annex L (Table L.2). + +Especially for transport, it is acknowledged that there is a lack of transparent secondary data for many unit processes. + +Additionally, the inclusion of generic processes for the different life cycle stages shall be clearly stated and reported. This may be shown in a flow diagram. + +Deviations from generic processes shall be reported according to Table L.3. + +For the reporting of transport and travel refer to Annex L (Table L.4). + +State if data are missing or if they are included in, e.g., support activity data are included but could not be reported separately. + +##### **10.2.2.2 Raw material acquisition** + +The use of raw materials shall be transparently reported as outlined below. The most important metals from recycling point of view shall always be stated. + +Other materials can be shown as well but such reporting is optional. + +For an appropriate reporting format refer to Annex L (Table L.5). + +NOTE – At the time of publication, some of the requirements in Table L.5 are considered challenging due to limitations in LCA tool, lack of data, limitations in data granularity, etc. It is thus recognized that compliance to these requirements may not be possible at the time this Recommendation is published. + +Deviation(s) from the requirements shall be clearly justified and reported. + +##### **10.2.2.3 Production** + +###### **10.2.2.3.1 Parts production** + +Compliance with Annex E (Table E.1) shall be reported and any deviation shall be described and justified. For an appropriate reporting format refer to Annex L (Table L.6). + +##### **10.2.2.4 Use** + +###### **10.2.2.4.1 ICT goods use** + +The basis and rationale for the energy consumption values for the ICT goods use stage shall be reported together with the annual value of the energy consumption. For an appropriate reporting format refer to Annex L (Table L.7). + +The model of distribution over time of different usage modes including power off and idle and the rationale for those shall be transparently reported. + +For an appropriate reporting format refer to Annex L (Table L.7). + +###### **10.2.2.4.2 Support goods use** + +The basis and rationale for the energy consumption values for the support goods use shall be transparently described and justified. For an appropriate reporting format refer to Annex L (Table L.7). + +##### **10.2.2.5 EoLT** + +If EoLT is included, any deviations from Annex F shall be transparently reported and justified. For an appropriate reporting format refer to Annex L (Table L.8). + +#### **10.2.3 LCI results** + +For LCI, the following items shall be reported transparently: total use of primary energy and electricity. + +NOTE – The cumulative energy demand method is appropriate to express primary energy usage. + +It is recommended to report land use and water use when applicable to the selected impact categories. + +Additionally, results for elementary flows according to Annex G (Table G.1) could be transparently reported on an optional basis. If such reporting is not made, it is mandatory to describe unexpected results, lack of data, and other findings associated with the elementary flows. + +For an appropriate reporting format refer to Annex L (Table L.9). + +### **10.3 ICT network** + +#### **10.3.1 Example reporting** + +Figure 17 below illustrates how network-level LCA reporting can be built up by the goods level LCA data, using a typical wireless network as an example. The same principle applies for other types of networks, e.g., broadband, traditional fixed voice, IP-voice, local area network (LAN) and Internet protocol television (IPTV) networks. + +![Figure 17: Example of a reporting structure for a network LCA. The figure consists of two bar charts. The top chart, 'Goods level LCA', shows four categories: Raw material acquisition, Production, Use, and EoLT. The bottom chart, 'Network level LCA', shows GHG emissions [kg CO2e per subscriber per year] for eight categories: End-user goods, CPE, Access network, C&C network, Operator activities, Data transport, Data centre(s), and Service provider activities. The bars are stacked and color-coded: light grey for Raw material acquisition, production, and EoLT; dark grey for ICT goods use; and hatched for Operator support activities. A large downward arrow indicates the flow from Goods level LCA to Network level LCA. A legend at the bottom explains the color coding. The code L.1410(14)_F17 is present in the bottom right.](ce857617d1453e7e90edfaae561e2f62_img.jpg) + +Figure 17: Example of a reporting structure for a network LCA. The figure consists of two bar charts. The top chart, 'Goods level LCA', shows four categories: Raw material acquisition, Production, Use, and EoLT. The bottom chart, 'Network level LCA', shows GHG emissions [kg CO2e per subscriber per year] for eight categories: End-user goods, CPE, Access network, C&C network, Operator activities, Data transport, Data centre(s), and Service provider activities. The bars are stacked and color-coded: light grey for Raw material acquisition, production, and EoLT; dark grey for ICT goods use; and hatched for Operator support activities. A large downward arrow indicates the flow from Goods level LCA to Network level LCA. A legend at the bottom explains the color coding. The code L.1410(14)\_F17 is present in the bottom right. + +**Figure 17 – Example of a reporting structure for a network LCA** + +Additionally, the proposed network structure can also be used to report important high-level parameters such as quantities and energy consumption of included goods (see Table 6). + +**Table 6 – Example of reporting structure** + +| | Studied network (Example of wireless network) | Quantity | Energy consumption | +|-----------------------------|----------------------------------------------------------------|----------|--------------------| +| End-user goods | Mobile phone (user equipment (UE)) | | | +| Home goods | Fixed wireless terminal (FWT) | | | +| Access network | Radio base station (RBS) sites, control and core network sites | | | +| Service provider(s) | Wireless network operator business and O&M activities | | | +| Data transport/transmission | Allocation of shared data transport/transmission | | | +| Data centres/data rooms | Allocation of shared data centres/data rooms | | | + +#### 10.3.2 Total results + +For each environmental impact category studied, a diagram should be prepared splitting the impact of different parts of the network. Figures 17 and 18 show examples of network LCA reporting. + +Operating lifetime is also important for networks, and it is associated with the lifetime of the different nodes, which shall be reported. It shall be reported following the format of Annex L (Table L.11) which also describes the studied network. + +![Stacked bar chart showing environmental impact categories for various network components. The Y-axis represents kg CO2/year from 0 to 30. The X-axis lists components: End-user goods, CPE, Access network, C&C network, Operator activities, Data transport, Data centre(s), and Service provider activities. The legend indicates three categories: Operator support activities (dark grey), ICT goods use (medium grey), and Raw material acquisition, production, and EoLT (light grey).](ad5d2a8873e05b8dcc418cf609192c78_img.jpg) + +Total result <#kg CO2/year> +Study year: <20##> + +kg CO2/year + +| Category | Raw material acquisition, production, and EoLT (kg CO 2 /year) | ICT goods use (kg CO 2 /year) | Operator support activities (kg CO 2 /year) | Total (kg CO 2 /year) | +|-----------------------------|---------------------------------------------------------------------------|------------------------------------------|--------------------------------------------------------|----------------------------------| +| End-user goods | 15 | 10 | 0 | 25 | +| CPE | 5 | 15 | 0 | 20 | +| Access network | 4 | 20 | 0 | 24 | +| C&C network | 1 | 3 | 0 | 4 | +| Operator activities | 0 | 0 | 8 | 8 | +| Data transport | 1 | 2 | 0 | 3 | +| Data centre(s) | 0 | 5 | 0 | 5 | +| Service provider activities | 0 | 1 | 0 | 1 | + +L.1410(14)\_F18 + +Stacked bar chart showing environmental impact categories for various network components. The Y-axis represents kg CO2/year from 0 to 30. The X-axis lists components: End-user goods, CPE, Access network, C&C network, Operator activities, Data transport, Data centre(s), and Service provider activities. The legend indicates three categories: Operator support activities (dark grey), ICT goods use (medium grey), and Raw material acquisition, production, and EoLT (light grey). + +**Figure 18 – Environmental impact category indicator result diagram – example for network (diagram for global warming potential (GWP100) (CO2e))** + +Figure 18 shall be accompanied by the disclaimer "This LCA result cannot be compared to the result of another LCA unless all assumptions and modelling choices are equal". See further explanation in the scope of this Recommendation. + +Figure 18 shows an example of network LCA with a wide scope and it is not applicable to all studied product systems. + +Optionally, a diagram showing the distribution of impacts between sub-activities within each life cycle stage could also be reported in the same way as for ICT goods (see clause 10.2.1). + +Additionally, a diagram summarizing the distribution of environmental impact category indicators between life cycle stages shall be prepared together with absolute figures, as shown in the Annex L (Table L.10). The diagram may be presented according to Figure 19. + +![Horizontal stacked bar chart showing environmental impact category indicators for various network units. The chart includes categories for raw material acquisition, production, and EoLT for end user goods/CPE, network use/operator activities, and data services. Units listed include RDMR, RDW, LU, ETFW, A, POF, ET, EA, IRE, IRH, RI/PM, HTNC, HTC, OD, and CC. The x-axis shows percentages from 0% to 100%.](23f81127919fb6dcb76edf3f78f56953_img.jpg) + +Legend: + +- Raw material acquisition (A)\*, production (B)\*, and EoLT (D)\* end user goods/CPE +- Use (C) end user goods/CPE +- Raw material acquisition (A)\*, production (B)\*, and EoLT (D)\* network use/operator activities +- Use (C) network use/operator activities +- Raw material acquisition (A)\*, production (B)\*, and EoLT (D)\* data services +- Use (C) data services + +L.1410(14)\_F19 + +Horizontal stacked bar chart showing environmental impact category indicators for various network units. The chart includes categories for raw material acquisition, production, and EoLT for end user goods/CPE, network use/operator activities, and data services. Units listed include RDMR, RDW, LU, ETFW, A, POF, ET, EA, IRE, IRH, RI/PM, HTNC, HTC, OD, and CC. The x-axis shows percentages from 0% to 100%. + +**Figure 19 – Environmental impact category indicators overview for networks** + +Figure 19 shall be accompanied by the disclaimer "This LCA result cannot be compared to the result of another LCA unless all assumptions and modelling choices are equal". See further explanation in the scope. + +Details of network energy consumption shall be reported with a split of different elements of the network. An example of 'Table for Reporting' is provided in Table L.12. + +### 10.4 ICT services + +#### 10.4.1 Example reporting + +Reporting at the service level may be structured based on the various network parts used by the ICT service, in the same manner as networks are reported. Each bar should then show the relationship between the dedicated impact of the ICT service under study and the impact associated with all other ICT services (see Figure 20), in order to illustrate the relative contribution of each activity to the total amount of environmental load. + +![Figure 20: Bar chart showing GHG emissions [kg CO2e per subscriber per year] for various ICT services. The chart compares 'Services' (light grey) and 'Other services' (dark grey) across eight categories: End-user goods, CPE, Access network, C&C network, Operator activities, Data transport, Data centre(s), and Service provider activities. The y-axis has four horizontal grid lines but no numerical scale. End-user goods, CPE, and Access network show the highest emissions, while Service provider activities show the lowest.](de7b700c44b3911907685dffd54fc50f_img.jpg) + +| Category | Services (kg CO 2 e per subscriber per year) | Other services (kg CO 2 e per subscriber per year) | +|-----------------------------|---------------------------------------------------------|---------------------------------------------------------------| +| End-user goods | ~0.1 | ~0.8 | +| CPE | ~0.1 | ~0.6 | +| Access network | ~0.1 | ~0.8 | +| C&C network | ~0.1 | ~0.2 | +| Operator activities | ~0.1 | ~0.3 | +| Data transport | ~0.1 | ~0.2 | +| Data centre(s) | ~0.1 | ~0.2 | +| Service provider activities | ~0.1 | ~0.1 | + +L.1410(14)\_F20 + +Figure 20: Bar chart showing GHG emissions [kg CO2e per subscriber per year] for various ICT services. The chart compares 'Services' (light grey) and 'Other services' (dark grey) across eight categories: End-user goods, CPE, Access network, C&C network, Operator activities, Data transport, Data centre(s), and Service provider activities. The y-axis has four horizontal grid lines but no numerical scale. End-user goods, CPE, and Access network show the highest emissions, while Service provider activities show the lowest. + +**Figure 20 – Example of a reporting structure for ICT services** + +There is typically a multitude of services running over a telecommunications network. Assessing the impact of a single service most likely needs to be done by using allocations. Guidance for doing allocations in the context of services is given in clause 7.3.3.9. + +If the eight checklist items outlined in clause 7.2.3.5.2 are kept separate in the assessment and in the reporting, then Figure 21 shows an example of a possible reporting format. + +![Figure 21: Stacked bar chart showing the 'Amount of environmental load' for 'Targeted ICT goods, networks or services'. The chart is divided into eight segments representing different environmental impact categories. The legend lists these categories from top to bottom: ICT hardware, ICT software, Consumables and other supportive products, Site infrastructure, Office working environment (work processes), Transport (movement of goods), Travel (movement of people), and Storage of goods. The total height of the bar is divided into four horizontal sections by dashed lines.](36f40c75a057d3df5a27023925e5ed9f_img.jpg) + +L.1410(14)\_F21 + +Figure 21: Stacked bar chart showing the 'Amount of environmental load' for 'Targeted ICT goods, networks or services'. The chart is divided into eight segments representing different environmental impact categories. The legend lists these categories from top to bottom: ICT hardware, ICT software, Consumables and other supportive products, Site infrastructure, Office working environment (work processes), Transport (movement of goods), Travel (movement of people), and Storage of goods. The total height of the bar is divided into four horizontal sections by dashed lines. + +**Figure 21 – Example of results of an LCA per functional unit separating checklist items** + +#### 10.4.2 Total results + +For each environmental impact category studied, a diagram should be prepared splitting the impact of different parts of the network. Figures 22a and 22b show examples of ICT service LCA reporting. + +Operating lifetime is important also for services, but it is associated with the lifetime of the different nodes, which shall be reported. Reporting should be made in accordance with Annex L (Table L.11) which also describes the studied network(s). + +![Stacked bar chart showing environmental impact (kg CO2e/year) for various services. The chart compares 'Service (product system under study, all life cycle stages)' (black) and 'Other services provided by the network' (red).](b91520013ba00f460455724c767a470d_img.jpg) + +Total result <#kg CO2e/year> +Study year: <20##> + +kg CO2e/year + +| Service Category | Service (product system under study, all life cycle stages) [kg CO 2 e/year] | Other services provided by the network [kg CO 2 e/year] | Total [kg CO 2 e/year] | +|-----------------------------|-----------------------------------------------------------------------------------------|--------------------------------------------------------------------|-----------------------------------| +| End-user goods | ~1 | ~24 | ~25 | +| CPE | ~1 | ~19 | ~20 | +| Access network | ~2 | ~22 | ~24 | +| C&C network | ~1 | ~3 | ~4 | +| Operator activities | ~1 | ~6 | ~7 | +| Data transport | ~0.5 | ~2.5 | ~3 | +| Data centre(s) | ~0 | ~5 | ~5 | +| Service provider activities | ~1 | ~0.5 | ~1.5 | + +L.1410(14)\_F22a + +Stacked bar chart showing environmental impact (kg CO2e/year) for various services. The chart compares 'Service (product system under study, all life cycle stages)' (black) and 'Other services provided by the network' (red). + +**Figure 22a – Environmental impact category indicator result diagram – example for services (diagram for global warming potential (GWP100) (CO2e))** + +![Bar chart showing environmental impact category indicator result for global warming potential (GWP100) in kg CO2e/year across various life cycle stages. The chart title is 'Total result <#kg CO2e/year> Study year: <20##>'. The y-axis is labeled 'kg CO2e/year' and ranges from 0 to 3. The x-axis lists eight categories: End-user goods, CPE, Access network, C&C network, Operator activities, Data transport, Data centre(s), and Service provider activities. The 'Access network' bar is the highest at 2.0 kg CO2e/year. Other bars show 1.0 for End-user goods, CPE, and C&C network; 0.5 for Operator activities and Data transport; 0.2 for Data centre(s); and 0.7 for Service provider activities. A legend indicates the black bars represent 'Service (product system under study, all life cycle stages)'. The code 'L.1410(14)_F22b' is in the bottom right.](67c5d79e4719deb94b1422a400804482_img.jpg) + +| Life Cycle Stage | Impact (kg CO 2 e/year) | +|-----------------------------|------------------------------------| +| End-user goods | 1.0 | +| CPE | 1.0 | +| Access network | 2.0 | +| C&C network | 1.0 | +| Operator activities | 0.5 | +| Data transport | 0.5 | +| Data centre(s) | 0.2 | +| Service provider activities | 0.7 | + +Bar chart showing environmental impact category indicator result for global warming potential (GWP100) in kg CO2e/year across various life cycle stages. The chart title is 'Total result <#kg CO2e/year> Study year: <20##>'. The y-axis is labeled 'kg CO2e/year' and ranges from 0 to 3. The x-axis lists eight categories: End-user goods, CPE, Access network, C&C network, Operator activities, Data transport, Data centre(s), and Service provider activities. The 'Access network' bar is the highest at 2.0 kg CO2e/year. Other bars show 1.0 for End-user goods, CPE, and C&C network; 0.5 for Operator activities and Data transport; 0.2 for Data centre(s); and 0.7 for Service provider activities. A legend indicates the black bars represent 'Service (product system under study, all life cycle stages)'. The code 'L.1410(14)\_F22b' is in the bottom right. + +**Figure 22b – Environmental impact category indicator result diagram – example for services (diagram for global warming potential (GWP100) (CO2e)** + +Figures 22a and 22b should be used alternatively depending on the scope of the assessment. Figures 22a and 22b shall be accompanied by the disclaimer "This LCA result cannot be compared to the result of another LCA unless all assumptions and modelling choices are equal". See further explanation in the scope and clause 6.3. + +Allocation of network data to the service shall be reported. It should be reported according to Annex L (Table L.13). + +Additionally, a diagram summarizing the distribution of impact category indicators between life cycle stages for the service product system under study shall be presented together with absolute figures, as shown in Table L.10. Figure 23 provides an example. + +![Figure 23: Environmental impact category indicators examples overview for services. A horizontal stacked bar chart showing the percentage contribution of different environmental impact categories for various units. The x-axis represents the percentage from 0% to 100%.](37e4831a48bd47b99dcf6837787652ae_img.jpg) + +The chart displays the environmental impact category indicators for 15 different units. The categories are stacked horizontally for each unit, showing their relative contribution to the total score. The legend identifies five categories: + +- Raw material acquisition (A)\*, production (B)\*, and EoLT (D)\* end user goods/CPE (White) +- Use (C) end user goods/CPE (Light Gray) +- Raw material acquisition (A)\*, production (B)\*, and EoLT (D)\* network use/operator activities (Medium Gray) +- Use (C) network use/operator activities (Dark Gray) +- Raw material acquisition (A)\*, production (B)\*, and EoLT (D)\* data services (Dotted) +- Use (C) data services (Hatched) + +Units listed on the y-axis: RDMR [unit] Total score, RDW [unit] Total score, LU [unit] Total score, ETFW [unit] Total score, A [unit] Total score, POF [unit] Total score, ET [unit] Total score, EA [unit] Total score, IRE [unit] Total score, IRH [unit] Total score, RI/PM [unit] Total score, HTNC [unit] Total score, HTC [unit] Total score, OD [unit] Total score, CC [unit] Total score. + +L.1410(14)\_F23 + +Figure 23: Environmental impact category indicators examples overview for services. A horizontal stacked bar chart showing the percentage contribution of different environmental impact categories for various units. The x-axis represents the percentage from 0% to 100%. + +**Figure 23 – Environmental impact category indicators examples overview for services** + +Figure 23 shall be accompanied by the disclaimer "This LCA result cannot be compared to the result of another LCA unless all assumptions and modelling choices are equal". See further explanation in the scope and clause 6.3. + +In addition to the service reporting described above, the general reporting principles for networks shall apply. + +## 11 Critical review + +Critical review is a process to verify whether an LCA has met the requirements for methodology, data, interpretation and reporting and whether it is consistent with the main principles (relevance, completeness, consistency, accuracy and transparency). Any critical review shall be performed according to the requirements of [ISO 14040] and [ISO 14044], and those contained in this Recommendation. The scope and type of critical review desired shall be defined in accordance with [ISO 14044] clauses 4.2.3.8 and 6. + +In case of comparative assertions intended for public disclosure, the report of the LCA should be reviewed by a panel of interested external parties. In this case, the LCA practitioner should refer to [ISO 14040] and [ISO 14044] *for further details*. + +# PART II + +## **Comparative analysis/LCA between ICT and reference product systems (baseline scenario): framework and guidance** + +## **12 General description of comparative analysis** + +### **12.1 Need for comparative analysis** + +With the growth of ICT, the use of ICT goods, networks and services will continue to increase, as will the associated environmental load, also referred to as the first-order effect. This effect represents the life cycle environmental load emerging from processes such as design, production and installation of software and hardware, installation of ICT goods and networks, and from disposal and recycling, as well as from the use stage. However, through its second-order effects, ICT offers the potential to replace or rationalize more energy and resource intensive processes, and is in many cases expected to deliver a net positive impact on the environment. [b-ITU-T L.1480] provides guidance for assessing second-order effects when the use of ICT solutions impact GHG emissions of other sectors. Moreover, [b-ITU-T L.1480] guides also the assessment of higher order effects such as rebound. + +Comparative LCAs between an ICT based system and a reference product system (e.g., comparison between a face-to-face business meeting including air transport and the ICT service videoconference) aim to compare LCA results for different products, systems, or services that offer the same or similar functions. + +In general, the time perspective applied, as well as the scale of introducing the ICT based product system is crucial to the modelling. These perspectives may vary with study scope and purpose, e.g., a small-scale application of a videoconferencing system will not in the near future impact the number of airplanes used, while a large-scale application may have a considerable impact over a medium time frame. + +Infrastructure, e.g., highways for transportation, is generally assumed to exist independently of the introduction of new services and shall be excluded. However, in some LCAs focusing on large scale effects of services, infrastructure effects may be applicable to the studied product system (i.e., for an LCA trying to examine the effects of large-scale, long-term implications of a wide application of videoconferencing). In those cases, infrastructure associated impacts should be reported separately. + +The handling of time perspective and scale shall be disclosed and justified in the report. + +To quantify the net environmental impact when introducing an ICT solution, the environmental impact of both the ICT product system itself and the reference product system shall be assessed from a life cycle perspective. For further guidance refer to Part I. Potentially the reference product system could be any product system including another ICT based system. + +The net environmental impact resulting from the introduction of ICTs is calculated as the difference between the environmental load of the reference product system which could be avoided by introducing the ICT based system, and the environmental load of the ICT based system itself. + +To ensure that the comparative assessment gives a relevant result, the full life cycle of both systems shall always be considered. However, cut-off may be performed according to clause 13.2.3. + +Correct comparisons also require that the same goal, scope, system boundaries and functional unit are used for both product systems. + +From an LCA perspective, the reference product system and the ICT product system shall mimic each other as far as possible, and the LCA practitioner shall model both systems in an unbiased way. In reality, the two product systems may differ with respect to quality, e.g., the experience of a face-to-face meeting is different from that of a videoconference meeting. + +Usually, the most challenging part for a comparative assessment is to collect real-world data for the use stage both for the reference system and for the ICT based system. Lack of real-world data can be bridged by scenarios. The impact from the scenarios on the results is preferably evaluated by the use of sensitivity analysis, where parameters for scenarios/assumptions made are varied to track their importance for results and conclusions. + +Considering the complexities associated with comparative assessments, restrictions as to the interpretation of the results and the equivalence of the ICT and reference product systems are to be carefully observed, to avoid misinterpretation of results. + +### 12.2 Target systems for comparative analysis + +Two different applications for comparative assessment are targeted by this Recommendation. + +*Case 1 – Comparison between a reference product system (non-ICT) and an ICT good, network or service product system* + +*Case 2 – Comparison between two ICT goods or two ICT networks or two ICT services.* + +Corresponding to this Recommendation, [b-ITU-T L.1480] provides further guidance. Currently, [b-ITU-T L.1480] focuses only on greenhouse gas (GHG) emissions and provides guidance for assessing how the use of information and communication technology (ICT) solutions impacts GHG emissions of other sectors covering the net second order effect (i.e., the resulting second order effect after accounting for emissions due to the first order effects of the ICT solution), and the higher order effects such as rebound. + +The LCA practitioner should take care in understanding the intended effect of the studied ICT solution when compared to a reference product system containing another ICT solution. If the intended effect of the ICT solution refers to effect associated with activities in other sector than ICT sector, this would be qualified as an enablement effect (impacts on other sectors). In that case, ITU-T L.1480 provisions are applicable. + +In another situation, when the intended effect refers to effects associated with activities belonging to the ICT sector, this could not be qualified as an enablement effect but shall be qualified as reduction of first-order effects, as this only impacts the footprint of the ICT sector. These effects are not second order-effects (which refer to effects on emissions other than those associated with first order effects of ICTs) and thus [b-ITU-T L.1480] is not applicable. In the case of a reduction of first-order effects, the comparative assessment would correspond to Case 2 (comparison between two ICT product systems). + +*First case: comparison between a reference product system (non-ICT) and an ICT good, network or service product system.* + +In this case, the product systems are the reference product system (non-ICT) and the ICT good, network or service product system. The former is the business-as-usual case (so-called baseline case) where the ICT good, network or service is not applied. The latter is the case where the ICT good, network or service is applied. The purpose of this comparison is to understand the second-order effects when introducing an ICT good, network or service product system as a replacement or optimization for a reference product system. Such effects include a reduction in environmental impact in terms of GHG emission savings in for instance, commuting, air flights, hotel stays, etc. + +*Second case: comparison between two ICT goods or two ICT networks or two ICT services.* + +In this case, the two target systems are different ICT goods or ICT networks or ICT services. One may be an older ICT good, ICT network or ICT service, the other a newer one. Goods shall be compared with each other, ICT networks shall be compared with each other and ICT services shall be compared with each other. + +### **12.3 Principles of comparisons between systems (comparative analysis)** + +#### **12.3.1 First case: comparison between a reference product system (non-ICT) and an ICT good, network or service product system** + +In this case, in order to assess the second-order effects of the ICT solution, a comparative study between the reference product system (non-ICT) and the ICT product system is conducted. In this comparative LCA study, the scope of the LCA study shall be defined in such a way that the two systems can be compared. Systems shall be compared using the same functional unit and equivalent methodological considerations, such as performance, system boundary, data quality, allocation procedures and cut-off rules. Any differences between systems regarding these parameters shall be identified and reported. + +Both first-order and second-order effects should be considered when comparing a scenario based on the use of a reference product system and the situation after adoption of ICT goods, networks and services. + +Using ICTs has the potential to enhance energy efficiency and reduce the need, for instance, for transport and travel, etc. To assess the impact on the second order effects, it is important to consider environmental load reduction effects by using ICT. The most important effects are listed in clause 13.5 and Appendix X. In addition, other load reduction effects may also be relevant and should then be considered as well. + +#### **12.3.2 Second case: comparison between two ICT goods or two ICT networks or two ICT services** + +Also in this case, the scope of the LCA study shall be defined in such a way that the two systems can be compared. Both systems shall be assessed using the same functional unit and equivalent methodological considerations, such as system boundary, data quality, allocation procedures and cut-off rules. Any differences between systems regarding these parameters shall be identified and reported. + +When a product has several life cycles, it is essential to include all the effects of the refurbishment in the assessment of its environmental impact. These effects shall be included into each of the applicable life cycle stages and into cumulative cradle to grave assessment. + +NOTE – The effects of refurbishment can be positive or negative with respect to the reasonable (average) renewals of the product with new material. + +Appendix XV shows one example of an analysis with different refurbishment configurations. + +#### **12.3.3 Common principles** + +In the case of comparative analysis, if the purpose is to assess the difference in impact between the two product systems, rather than the total impact of each product system, processes or input/output data may be excluded if they are the same in both product systems. + +A schematic illustration of a comparative assessment is shown in Figure 24. Figure 24 indicates that the reference product system and the ICT goods, networks and services product system are assessed separately and then compared. + +The assessment of the ICT-based system shall be performed in accordance with Part I. + +When making comparisons, it is important to keep in mind that the functional unit used shall be applicable to both the reference product system and the system of ICT goods, networks and services. + +For the reference product system, applicable requirements in this Recommendation shall be applied, e.g., requirements regarding data quality, cut-off, etc. To get further guidance on system boundaries and other product system specific considerations (for the reference product system), sector-specific standards should be used if available. + +![Figure 24: Comparative assessment of a reference product system and an ICT goods, networks and services product system. The diagram shows two parallel life cycle assessment (LCA) processes. The left process is for 'Target ICT goods/NW/services' and the right is for 'Reference product system'. Both follow a similar flow: Goal and scope definition, Inventory analysis, Impact assessment, and Interpretation. Arrows indicate the flow and feedback within each process. Below these, a 'Comparative analysis' box contains a bar chart comparing the 'Environmental load' of the two systems. The chart shows two bars: a dotted bar for 'Target ICT goods/NW/services' and a hatched bar for 'Reference product system'. A double-headed arrow points between the two bars, indicating a comparison. The label 'L.1410(14)_F24' is in the bottom right corner.](c6212a3b14736d6a8c81ace75ae94ccf_img.jpg) + +Figure 24: Comparative assessment of a reference product system and an ICT goods, networks and services product system. The diagram shows two parallel life cycle assessment (LCA) processes. The left process is for 'Target ICT goods/NW/services' and the right is for 'Reference product system'. Both follow a similar flow: Goal and scope definition, Inventory analysis, Impact assessment, and Interpretation. Arrows indicate the flow and feedback within each process. Below these, a 'Comparative analysis' box contains a bar chart comparing the 'Environmental load' of the two systems. The chart shows two bars: a dotted bar for 'Target ICT goods/NW/services' and a hatched bar for 'Reference product system'. A double-headed arrow points between the two bars, indicating a comparison. The label 'L.1410(14)\_F24' is in the bottom right corner. + +**Figure 24 – Comparative assessment of a reference product system and an ICT goods, networks and services product system** + +### 12.4 Procedures of comparisons between systems (comparative analysis) + +As indicated above (in Figure 24), the assessment procedure contains several steps: + +- Definition of goal, functional unit and scenarios +- Definition of system boundaries for each product system +- Life cycle inventory including data collection for each product system +- Life cycle impact assessment for each product system +- Life cycle interpretation including comparison. + +## 13 Methodological framework of comparative analysis + +### 13.1 General requirements + +In the comparative situation, the full life cycle applies to both the ICT product system and the baseline system, unless cut-off is allowed in accordance with the cut-off rules outlined in clause 13.2.3. + +### 13.2 Goal and scope definition + +Goal definition includes defining the reason for conducting the comparative analysis, the target audiences, and the intended use of the results. + +Defining the scope includes defining the system boundaries of the ICT goods, networks and services product system and the reference product system. + +All the requirements stipulated in Part I for a system boundary definition shall be applied. + +#### 13.2.1 Functional unit + +The functional unit shall take into account the general rules outlined in Part I, clause 7.2.2 and [ISO 14044] clause 4.2.3.2. + +Additionally, the functional unit shall be defined so that it is applicable both to the ICT goods, networks and services product system and the reference product system. For example, when + +comparing a videoconferencing system with a travel-based reference product system, an appropriate functional unit may be one meeting or the total number of meetings during one year. + +The reference flow shall be defined to quantify the functional unit. In other words, for the functional unit of one meeting, for instance, the reference flow for the systems of ICT goods, networks and services and the reference product system shall be defined. + +#### **13.2.2 System boundaries** + +Two different system boundaries shall be defined which are applicable for the ICT goods, networks and services product system and for the reference product systems, respectively. + +The use stage scenarios need to model the user and the user profile for both systems. Key parameters for the systems of ICT goods, networks and services could include, e.g., number of users and amount of data traffic. For the reference product system parameters such as distance travelled, average number of participants, and building area may be relevant. + +A meeting can for example be characterized by the required energy consumption integrated over the average meeting duration, the average number of participants and the cumulative distance travelled. + +As the electricity mix differs between different regions, countries and world average, considerations shall be made to which electricity is used when assessing the environmental impact of the ICT goods, networks and services product system and the reference product systems. + +For the ICT goods, networks and services product system the system boundaries outlined in Part I, clause 7.2.3 apply. + +#### **13.2.3 Cut-off** + +##### **13.2.3.1 General** + +Generally, the cut-off rules in Part I (see clause 7.2.4 for details) shall apply for both ICT goods, networks and services and the reference product system. + +If a reference value is introduced in accordance with clause 7.2.4 for cut-off and is based on the reference product system, it could be referred to as the cut-off value of the reference product system. + +##### **13.2.3.2 Identification of life cycle stages and items important for comparison** + +Using ICTs has the potential to enhance the energy efficiency and reduce the need for transport and travel, etc. One important consideration for the cut-off, therefore, concerns the handling of second-order effects. In addition to considering the first-order effects in the cut-off as outlined in Part I, second-order effects need also be considered before cut-off. Both for the reference product system and for the ICT goods, networks and services, these effects are important to consider to avoid cut-off of processes within the life cycle which significantly impacts difference in environmental load between the scenarios related to such effects. + +In the case of comparative analysis, if the purpose is to assess the difference in impacts between the two product systems, rather than the total impact of each product system, processes or input/output data may be excluded if they are the same in both product systems. + +#### **13.2.4 Allocation** + +Generally, the allocation rules in Part I shall apply for ICT goods, networks and services. + +#### **13.2.5 Data quality requirements** + +The data quality requirements in Part I, clause 7.2.5, are applicable to both systems compared. + +Applicable data sources may be databases, field studies, published LCA results and relevant statistics. + +### 13.3 Life cycle inventory + +The calculation for the inventory analysis shall be performed in accordance with Part I, clause 7.3. + +### 13.4 Life cycle impact assessment + +The life cycle impact assessment is to be performed in accordance with Part I, clause 8. + +### 13.5 Life cycle interpretation + +#### 13.5.1 General + +The interpretation of results includes analysis of how the methodology was applied and should be performed in line with [ISO 14040] and [ISO 14044] and includes, e.g., conclusions, assumptions, limitations, uncertainty and data quality. + +The impact of scenarios as well as of assumptions related to allocation should also be analysed. For example, interpretation should include whether the allocation of data is based on primary or secondary data, if models are used and across which life cycle processes of an ICT product they have been applied. + +Results of a comparative analysis between a reference product system and systems of an ICT goods, networks and services product system can be obtained by calculating the difference in environmental impact between the reference product system and the systems of ICT goods, networks and services. The difference is termed second-order effect. Equation 1 shows the calculation formula. + +$$EI_{\text{difference},i} = EI_{\text{reference},i} - EI_{\text{ICT goods, networks, and services},i} \quad (1)$$ + +where: + +EI = environmental impact + +i = i-th comparison category + +$EI_{\text{difference},i}$ = i-th second order effect + +$EI_{\text{reference},i}$ = i-th EI of the reference product system + +$EI_{\text{ICT goods, networks, and services},i}$ = i-th EI of the systems of ICT goods, networks and services. + +Summing up $EI_{\text{difference},i}$ over i gives total $EI_{\text{difference}}$ or the second order effect of the systems of ICT goods, networks and services over the reference product system. Equation 2 shows the formula for calculating the second order effect. + +$$\text{Total } EI_{\text{difference}} = \sum EI_{\text{difference},i} \quad (2)$$ + +A positive result (Total $EI_{\text{difference}}$ is positive) denotes a positive impact on the environment and a negative value (Total $EI_{\text{difference}}$ is negative) represents a negative impact. A positive second-order effect indicates the reduction of the environmental impact due to the introduction of the ICT product system. A negative second order effect indicates the opposite. + +The number of comparison items are up to the discretion of the LCA practitioner, and the structuring of data may vary between LCAs. + +Table 7 shows an example of comparison categories, based on six comparison items, and the potential corresponding second-order effects. Depending on the type of ICT product system and corresponding reference product system, these categories may not be used and other categories may be added. Additionally, the LCA practitioner may choose to structure the data based on other factors, e.g., per subnetwork type. + +**Table 7 – Comparison category and its second-order effects** + +| Comparison categories | Second-order effects | +|-------------------------------|-----------------------------------------------------------------------------------------------------------------------------| +| Consumption of goods | By reducing goods consumption (paper, etc.), EI related to goods can be reduced. | +| Energy consumption | By enhancing the efficiency of power and energy use, EI related to power. can be reduced. | +| Movement of people | By reducing the movement of people, EI required for transportation can be reduced. | +| Movement and storage of goods | By reducing the movement of goods, EI required for transportation can be reduced. | +| Improved work efficiency | By using office space efficiently, power consumption for lighting, air conditioning, etc. can be reduced, thus reducing EI. | +| Waste | By reducing waste emissions, EI for waste disposal, etc. can be reduced. | + +Appendix X lists examples for calculating second order effects for the six comparison categories. [b-ITU-T L.1480] gives further guidance for provisioning and calculating second order effects. + +#### 13.5.2 Sensitivity analysis + +For the handling of sensitivity analysis refer to Part I, clause 9.3. + +Especially when modelled data is used, different scenarios should be assessed to establish a range of potential outcomes to limit the uncertainty. For instance, to understand the impact of an ICT solution, it is advisable to assess how its impact varies with the scale of adoption, considering different relevant scenarios. + +#### 13.5.3 Uncertainty analysis + +For the handling of uncertainty analysis refer to Part I, clause 9.2. + +## 14 Reporting + +In addition to the general reporting rules outlined in Part I, clause 10, the following specific consideration applies for comparative assessment. + +When the result of a comparative analysis between an ICT system and a reference product system (another ICT system or a non-ICT system) is reported as an environmental impact assessment, the environmental impact should specify the life cycle stages. It may be detailed according to checklist items if assessed in an LCA of ICT goods, networks and services product system, in accordance with the goal and scope of the LCA. + +Any cut-off made during a study shall be clearly stated in the study report, e.g., the exclusion of life cycle processes which are considered insignificant should be justified. + +The results may either be given as absolute amounts or as a relative difference between the systems. Thus, instead of reporting the calculated absolute amount of environmental impact, a relative difference (possibly as a percentage) between the impact from the ICT system and the impact from the reference product system may be presented. + +Some examples are shown below. + +The percentage of change in environmental impact through the introduction of ICTs may be calculated as a result of the following equation. + +Percentage change in environmental impact through the introduction of ICT systems is given by Equation 3: + +$$\text{ICT goods, networks, and services} = \text{EI}_{\text{difference}} / \text{EI}_{\text{reference}} \times 100 \quad (3)$$ + +where EI is the assessed environmental impact. + +The calculation result shown by Figure 25 indicates a positive impact on the environment when the percentage change value is positive and a negative impact on the environment when it is negative. Figure 26 illustrates instead an example of comparative analysis between an ICT product system and a reference product system with stages of a life cycle. + +![Figure 25: Bar chart comparing GHG emissions (kg-CO2e) between a Reference product system and a Targeted ICT. The Reference product system bar is solid dark grey. The Targeted ICT bar is a stacked bar with nine segments. An arrow points from the top of the Reference bar to the Targeted ICT bar, labeled 'Percentage of change in environmental load through introduction of ICTs: X%'. A legend on the right lists the segments for Targeted ICT: ICT hardware (dotted), ICT software (diagonal lines), Consumables and other supportive products (horizontal lines), Site infrastructure (vertical lines), Office working environment (work processes) (long horizontal lines), Transport (movement of goods) (light grey), Travel (movement of people) (diagonal lines), Storage of goods (cross-hatch), and Others (dark grey).](b3faf87063b80c8f67bb574a903ca7e0_img.jpg) + +Figure 25: Bar chart comparing GHG emissions (kg-CO2e) between a Reference product system and a Targeted ICT. The Reference product system bar is solid dark grey. The Targeted ICT bar is a stacked bar with nine segments. An arrow points from the top of the Reference bar to the Targeted ICT bar, labeled 'Percentage of change in environmental load through introduction of ICTs: X%'. A legend on the right lists the segments for Targeted ICT: ICT hardware (dotted), ICT software (diagonal lines), Consumables and other supportive products (horizontal lines), Site infrastructure (vertical lines), Office working environment (work processes) (long horizontal lines), Transport (movement of goods) (light grey), Travel (movement of people) (diagonal lines), Storage of goods (cross-hatch), and Others (dark grey). + +Figure 25 – Example of comparative analysis between an ICT product system and a reference product system with checklist items + +![Figure 26: Bar chart comparing GHG emissions (kg-CO2e) between a Reference product system scenario and an ICT product system scenario. The Reference product system scenario bar is solid dark grey. The ICT product system scenario bar is a stacked bar with four segments. An arrow points from the top of the Reference bar to the ICT product system bar, labeled 'Percentage change in GHG emissions through introduction of ICT: Y%'. A legend on the right lists the segments for ICT product system: EoLT (black), Use (dark grey), Production (medium grey), and Raw materials acquisition (light grey).](07b0d4a97040103ce6c822c3983a9c05_img.jpg) + +Figure 26: Bar chart comparing GHG emissions (kg-CO2e) between a Reference product system scenario and an ICT product system scenario. The Reference product system scenario bar is solid dark grey. The ICT product system scenario bar is a stacked bar with four segments. An arrow points from the top of the Reference bar to the ICT product system bar, labeled 'Percentage change in GHG emissions through introduction of ICT: Y%'. A legend on the right lists the segments for ICT product system: EoLT (black), Use (dark grey), Production (medium grey), and Raw materials acquisition (light grey). + +Figure 26 – Example of comparative analysis between an ICT product system and a reference product system with stages of a life cycle + +## 15 Critical review + +The critical review should be performed in accordance with the principles outlined in Part I, clause 11 for the ICT product system, the reference product system and the comparison between them. + +## Annex A + +### Details regarding the handling of software + +(This annex forms an integral part of this Recommendation.) + +This annex details some central aspects which shall be considered when assessing the environmental impacts of software. + +### *Life cycle stages and allocation principles for software* + +For each of the software categories described in clause 7.1.4.2, its intended use and sales volumes (i.e., number of licences/packages) need to be considered. + +Design, development, and production stages should be considered in LCAs of ICT goods, networks and services. Moreover, for commercial software products the environmental impact of the procurement stage should also be considered. + +### *Activities associated with the use of software* + +The following items are examples of activities related to the software design and production that cause an environmental impact. + +- Electricity consumption of ICT goods such as computers, communication goods and printers. +- Electricity consumption of offices such as air conditioning and illumination. +- Consumption of the consumables such as paper or printer toner. +- Recycling and disposal of waste. + +The above activities are applicable both to purchased software and software developed in-house. + +#### *Procedures for data collection* + +The preferred choice for data collection is to use primary data from the supplier. + +For software made by the organization using it, primary data as outlined above (e.g., electricity consumption, etc.), are available to the user for design and development stages. + +In this case, the environmental impact for these activities may be calculated using the below formula (Equation A.1), by adding up the different environmental impact for different activities: + +$$E_a = E_1 + E_2 + E_3 + \dots + E_n \quad (A.1)$$ + +$E_a$ : Quantity of environmental load for software design and production + +$E_1, E_2, E_3, E_n$ : Quantity of environmental load for each activity. + +For procured software, the following method based on addition of environmental load per software can be applied (Equation A.2): + +$$E_b = O + B_1 + B_2 + M_1 + M_2 \quad (A.2)$$ + +$E_b$ : Quantity of environmental load of all software (CO2 emission, etc.) + +$O, B_1, B_2, M_1, M_2$ : Quantity of environmental load of the individual software to be procured (CO2 emission, etc.) + +However, if such data is not available, the procedures below can be applied. + +If GHG emission data is available for some software from a supplier, the load of other software may be estimated based on the selling prices and the known environmental load values, according to the following formula (Equation A.3): + +$$E_b = (W/p_1) \times S_1 \quad (A.3)$$ + +- Eb: Quantity of environmental load of all software (CO2 emission, etc.) +- W: Total amount of all software to be procured (selling price, etc.) +- p1: Amount of software for which their environmental loads are known (CO2 emission, etc.) +- S1: Quantity of the environmental load of software (w1) well-known quantity of environmental load (CO2 emission, etc.) + +An alternative method to overcome data shortage would be to make estimates based on economic input-output tables for environmental analysis, i.e., based on environment load emission values provided in tables of economic statistics, also considering the cost of software to be targeted. The following formula (Equation A.4) applies: + +$$S=w1 \times k \quad (\text{A.4})$$ + +- S: Environmental load with the design and production of software +- w1: Price of software to be targeted +- k: The emission factor in CO2 emission per price of software in currency unit. + +## Annex B + +### Modelling of unit processes + +(This annex forms an integral part of this Recommendation.) + +Data shall be collected, for each unit process that is included within the system boundary, in accordance with this annex. + +A unit process typically represents a facility where a product is produced, but it can also represent, e.g., an office or a store, or even an activity or a place where a service is produced. A unit process can also be a vehicle or a "mobile facility" that transport products. Non-production facilities are especially important to the ICT sector [b-EUR 24708 EN], as a large percentage of the total work is related to research and development (including software), operation, maintenance, etc. + +A unit process can be modelled as shown in Figure B.1. The generic unit process model includes a number of inputs and outputs and can be referred to as a facility LCI model or, in the shorter form, a facility model. + +NOTE – For example, the part unit processes in Table E.1. + +In many cases a facility handles not only the product system targeted by the LCA but also other product systems. In this situation, the facility data needs to be allocated to the studied/targeted product system in an appropriate way. For allocation rules please refer to clause 7.3.3. + +![Figure B.1 – The generic unit process model. A central rectangular box represents the unit process. Inputs from the left include: Resources input (depletion of land, water, natural resources), Energy input, and Product inputs (raw materials, parts). A single input from the top is Transport and travel. Outputs to the right include: Emissions to air, Emissions to water, Emissions to soil, and Waste outputs. A single output from the bottom is Product outputs. The diagram is labeled L.1410(14)_FB.1 in the bottom right corner.](0d9b44054c70dcda35129f11b97a912f_img.jpg) + +``` +graph TD; subgraph Inputs; direction LR; R["Resources input (depletion of land, water, natural resources)"] --> UP[Unit Process]; E["Energy input"] --> UP; P["Product inputs (raw materials, parts)"] --> UP; T["Transport and travel"] --> UP; end; UP --> O1["Emissions to air"]; UP --> O2["Emissions to water"]; UP --> O3["Emissions to soil"]; UP --> O4["Waste outputs"]; UP --> PO["Product outputs"]; style UP fill:#fff,stroke:#000,stroke-width:1px; +``` + +Figure B.1 – The generic unit process model. A central rectangular box represents the unit process. Inputs from the left include: Resources input (depletion of land, water, natural resources), Energy input, and Product inputs (raw materials, parts). A single input from the top is Transport and travel. Outputs to the right include: Emissions to air, Emissions to water, Emissions to soil, and Waste outputs. A single output from the bottom is Product outputs. The diagram is labeled L.1410(14)\_FB.1 in the bottom right corner. + +**Figure B.1 – The generic unit process model** + +Emissions to the environment and impact on or use or depletion of resource objects are referred to as elementary flows. All other inputs and outputs are defined as product flows. + +Each input of fuel and products, as well as each output of waste, may involve transportation which is then part of the input/output data connected to the unit process. + +Applicable support activities should also be considered for a production facility if applicable. + +#### Emissions (elementary flows) + +The following emissions shall be taken into account if applicable to the studied impact category(ies): + +- emissions to air +- emissions to water +- emissions to soil. + +Non-material emissions like radiation, odour and noise are beyond the scope of this Recommendation, as well as their direct impact on health. + +#### Resource objects (elementary flows) + +The following resource objects shall be taken into account, if applicable, to the studied impact category(ies): + +- material resource use (see RDMR, resource depletion mineral resources, Table 5) +- energy resource use (see RDMR, resource depletion fossil, Table 5). + +Additionally, the following resource objects should be taken into account, if applicable, to the studied impact category(ies): + +- fresh water use (see resource depletion (RDW), water) +NOTE – Fresh water refers to water from rivers, lakes, or subsoil water. +- land use. + +Species, biodiversity, and ecosystem depletion, as well as aesthetical values are beyond the scope of this Recommendation. + +A list of emissions and resource objects that shall be included, if applicable to the studied product system and impact category(ies), can be found in Annex G (Table G.1). + +#### Energy, product and services inputs + +Furthermore, the following inputs shall also be included, if applicable, to the studied impact category(ies): + +- electricity; +- other forms of delivered energy (district heating and cooling); +- fuels (typically indicates the fuels are incinerated on-facility or in a vehicle connected to the facility); +- primary products (products that are part of the final product in operation); +- secondary products (products that are not part of the final product in operation e.g., 2-propanol used as cleaning agent for PCBAs); +- transport, travel, and other services (can be seen as a special non-material secondary product input). + +#### Product, water and waste output + +Finally, the following flows shall also be included, if applicable, to the studied impact category(ies): + +- water discharge (to municipal sewage or recipient); +- waste fractions (residual waste fractions or waste fractions that need further treatment, also including material recycling and energy recovery); +- product output (the main purpose with the unit process or activity). + +A mandatory list of generic activities (unit processes) that have been found to be of importance for an LCA of *ICT goods, networks and services* can be found in Annex D. + +An informative list of typical *ICT goods, support goods and network goods* can be found in Appendices III and IV. + +## Annex C + +### Support activities + +(This annex forms an integral part of this Recommendation.) + +Whenever support activities are included in the scope of the study, the guidance in this annex shall be considered. + +All activities during the life cycle of an ICT goods, network or service, performed by an organization, are related to different kinds of organizational activities which in this Recommendation are referred to as *support activities*. + +The term *support activities* refers to activities that are specific to the goods network or service, but also to other general organizational activities needed to operate the company. The former could be e.g., marketing, sales, research and development; the latter could be data support, human resources support; communications, financial department, etc. + +Both these categories are associated with the use of buildings and travelling/transport, i.e., use of energy and material resources. + +The impact from specific activities could either be estimated based on detailed knowledge of the organizational structure (bottom-up), or by allocation from information regarding the total amount of employees in the organization and their impact (top-down). + +Optionally, the impact from consultants and services used by the organization could also be considered. + +Any support activities included in the LCA scope shall be clearly reported in terms of organization activities considered. + +The support activities for ICT manufacturer, operator and service providers have been given specific names: + +- ICT manufacturer support activities +- operator support activities +- service provider support activities. + +This is to highlight their importance. They have also been structured separately in Figures 7, 9 and 10. For other life cycle activities the support activities are embedded in the activity itself. + +As most activities during the life cycle are associated with support activities, the support activities could be seen as generic activities. However, in contrast to other generic processes (like travelling, transport, etc), the activity data for support activities are very much specific to the organization performing them, and need to be modelled specifically for different organizations. + +## Annex D + +### Generic processes + +(This annex forms an integral part of this Recommendation.) + +Table D.1 defines the generic processes (G1 to G7) which shall be included, if applicable, in LCAs for *ICT goods, networks and services*, as well as examples of categories and examples of unit processes to be included. Generic processes are processes that are applicable several times during the life cycle and could be used for several life cycle stages, and even several times per stage. As an example, the generic raw material process G5 is applicable to any raw material used during any life cycle stage, including the raw materials used during the Raw material acquisition stage (denoted A in Table 2). + +**Table D.1 – Generic processes for LCA of ICT goods** + +| Generic process | Generic process categories | Unit processes (for each category) | Product flow unit | Important issues | +|----------------------------|--------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| G1
Transport and travel | Road
Air
Ship
Train | Mandatory: Direct (during transport) emissions, Fuel supply chain (see Note 1)
Optional: Vehicle production, Infrastructure production | tonne×km,
kg×km,
Ctonne×km | Chargeable mass = Ctonne×km (function that also considers volume or density) (see Note 3) | +| G2
Electricity | National, regional and local producer electricity mixes | Mandatory: Fuel supply chain (see Note 1), "Raw Material Acquisition+Production+Distribution" where applicable for local renewable electricity generation, Direct emissions (during electricity production)
Optional: Power plant production, Dam production, the grid production, Nuclear waste treatment | kWh | This is also applicable to local production of electricity e.g., off-grid site electricity generation using e.g., photovoltaic modules and wind turbines. | +| G3 Fuels | Oil
Diesel
Petrol
Jet-fuel
liquefied petroleum gas (LPG)
liquefied natural gas (LNG)
Coal
Gas | Mandatory:
Fuel supply chain (see Note 1) | mass,
energy content | | + +**Table D.1 – Generic processes for LCA of ICT goods** + +| Generic process | Generic process categories | Unit processes (for each category) | Product flow unit | Important issues | +|-----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------|------------------------------------| +| G4 Other energy | District heating (hot water)
District heating (steam)
District cooling (cold water) as electricity | Mandatory: Fuel supply chain,
Direct emissions during energy/electricity production
Optional: Power plant production,
Infrastructure production | kWh | | +| G5 Raw material acquisition | See Annex H | Mandatory: Extraction
Processing | mass | | +| G6 End-of-life treatment | G6.1 EHW (Environmentally hazardous waste) treatment:
EHW (destruction and energy recovery)
Special EHW landfill
G6.2 Other waste treatment:
Diverse material recycling
Energy recovery (e.g., incineration, see Note 2)
Landfill
See Annex F for goods EoLT | G6.1: Recovery/treatment
G6.2: Recycling/recovery/treatment | mass,
(energy content) | | +| G7 Raw material recycling | Metal recycling
Other material recycling | Mandatory:
Smelting
Refining
Optional:
Plastic, paper | | Other material shall be considered | + +NOTE 1 – Extraction and production and distribution (transport). +NOTE 2 – Energy recovery of incineration processes is optional. +NOTE 3 – For each transport, the LCA practitioner should assess the studied good mass or volume, whichever is the limiting factor for the transport and also the vehicle maximum payload and/or available volume, respectively. In case the limiting factor is not known, both should be assessed. If mass is the limiting factor the "Product flow unit" can directly be assessed with a $\text{kg}\times\text{km} / \text{tonne}\times\text{km}$ formula. Otherwise, if volume is the limiting factor the "Product flow unit" should be assessed by adding a loading rate factor. + +## Annex E + +### Part types of ICT goods + +(This annex forms an integral part of this Recommendation.) + +Table E.1 lists the applicable parts and assembly types which shall be taken into account when performing an LCA of ICT goods, if applicable, to the ICT good (not ICT network). It also lists the corresponding part, assembly categories and unit processes. However, parts which are found insignificant according to the cut-off rules may be excluded. The list is to be regarded as a mandatory list and additional processes and parts may be identified and included as well, e.g., fuel cells. + +The intention of the list is to state what shall be considered to make sure that important parts are not forgotten. + +The intention is not to put requirements on modelling. In practice, it is often convenient to model the production processes for part categories separately, but other modelling is possible as long as the impact from the part category is included in the overall results. For raw materials acquisition it may be impractical to model goods at a part category level. + +NOTE – At the time of publication, some of the requirements in Annex E are considered as challenging due to LCA tool limitations, lack of data, limitations in data granularity, etc. It is thus recognized that compliance to all requirements in Annex E may not be possible at the time this Recommendation is published. + +Deviation(s) from the requirements shall be clearly motivated and reported. + +**Table E.1 – Mandatory set of parts and assembly unit processes for LCA of ICT goods** + +| Part/Assembly | Part/Assembly categories | Unit processes (for each part/assembly category) | Product flow unit | Important parameters which influence LCI data | +|-------------------------------|------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------|------------------------------------------|-----------------------------------------------| +| B1.1.1 Batteries (see Note 8) | Lead batteries
Lithium batteries
Nickel-cadmium batteries
Nickel-metal hydride batteries | Raw material acquisition,
Battery cell assembly (see Note 1),
Battery module (pack) assembly (see Note 2) | Piece (see Note 7), energy content, mass | Size | +| B1.1.2 Cables | Coaxial cables
Fibre cables
Power cables
network/signal cables
Connectors | Raw material acquisition,
Cable final assembly | Mass, piece (see Note 7) | Length | +| B1.1.3 Electro-mechanics | Connectors
Electric motors
Chargers
Speakers
Microphones
Camera objectives
Hard Disc Drives
Lighting (lamps) | Raw material acquisition,
Part final assembly | Mass, piece (see Note 7) | | + +**Table E.1 – Mandatory set of parts and assembly unit processes for LCA of ICT goods** + +| Part/Assembly | Part/Assembly categories | Unit processes (for each part/assembly category) | Product flow unit | Important parameters which influence LCI data | +|-------------------------------------|------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------| +| B1.1.4
Integrated circuits (ICs) | Processors, DSPs
ASICs
Memories
Microprocessors
Transistors and diodes | Front-end:
Special integrated circuit (IC) raw materials acquisition,
Wafer production,
Chip production ("the wafer fab")
Back-end: Raw material acquisition,
IC encapsulation | Piece, Mass.
Front-end: Die area [cm 2 ] where readily available. Die area refers to the total area within the IC package. If die area is not available, the total component mass is used for both front-end and back-end.
Back-end: piece package type or mass independent from package type where the die area is not available (see Note 3)
Transistors and diodes: Piece, mass, or as for ICs for front-end and back-end (see Note 7) | Yield in chip production
Business activities
Factory and machinery | +| B1.1.5
Mechanics/
Materials | Nuts, bolts, screws
Fronts
Frames
Racks
Cabinets
Towers
Containers
Solder | Raw material acquisition,
Part final assembly | Mass, piece (see Note 7) | | +| B1.1.6 Displays | Plasma display panel (PDP)
LCD (see Note 4)
light emitting devices (LED)
organic light emitting diodes (OLED) | Raw materials acquisition
Raw materials acquisition for special display panel materials,
Display module assembly,
Display panel assembly | Mass, active area, piece (see Note 7) | Yield
Business activities,
Factory and machinery | + +**Table E.1 – Mandatory set of parts and assembly unit processes for LCA of ICT goods** + +| Part/Assembly | Part/Assembly categories | Unit processes (for each part/assembly category) | Product flow unit | Important parameters which influence LCI data | +|-------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------|--------------------------------------------------------| +| B1.1.7 PCB | Plastic
Ceramic
Flex-film | Raw materials acquisition,
Raw materials acquisition for special printed circuit boards (PCB) materials,
Raw materials Acquisition for PCB semi-produced composite materials,
PCB final assembly | Mass, area of multilayer PCB, piece (see Note 7) | Yield
Business activities,
Factory and machinery | +| B1.1.8 Other PCBA components | Resistors
Capacitors
Inductors
Relays
LEDs
Potentiometers
Quartz crystal oscillators | Raw material acquisition,
Part final assembly | Mass, piece (see Note 7) | | +| B1.1.9 Packaging materials | Paper
Cardboard
Plastics
Wood
Steel | Raw material acquisition | Mass, volume (see Note 5) | Lifetime,
reuse,
energy recovery | +| B1.1.10 Black box modules | Products, devices, modules bought by ICT goods producer, or other actors in the supply chain, as complete products (e.g., cameras, modules, memories, printer cartridges. These products can also be complete ICT goods such as mobile phones and network equipment as well as storage devices, disk drives or power supply units). | "Cradle-to-gate" LCA from supplier (see Note 6) | Mass, piece (see Note 7) | Size, mass, technology | +| B1.1.11 Software module
For further guidance see Annex A | Software | Development: e.g., daily way to work for programmer, business trips for programmer, electricity usage of ICT goods used by programmer, office lighting. | Megabyte | | + +**Table E.1 – Mandatory set of parts and assembly unit processes for LCA of ICT goods** + +| Part/Assembly | Part/Assembly categories | Unit processes (for each part/assembly category) | Product flow unit | Important parameters which influence LCI data | +|---------------|------------------------------------------|-------------------------------------------------------------------------------------------------------------------|-------------------|-----------------------------------------------| +| | | Production: e.g., manuals production, data medium production, download size if software is available as download. | | | +| B1.2 Assembly | PCBA module assembly,
Final Assembly, | Assembly process
Warehousing,
Packaging. | | | + +NOTE 1 – Example: Battery cell assembly could include the energy used in the cell plant production and the transport of cells to the battery module (pack) assembly. In the battery cell assembly, the anode, cathode, separator and electrolyte and plastic parts are usually used to make the cell. + +NOTE 2 – Example: Battery module (pack) assembly could include the energy used in the assembly plant production, transport to B1.2. In battery module (pack) assembly, the battery cell, PCBAs, cables, and containers are usually used to make the battery module (pack). + +NOTE 3 – Example: A BGA289 package. Die area 0.166 cm2. GWP per BGA289 = CO2e/die area in cm2 × 0,166 + CO2e/piece ball grid array (BGA) package type back-end process. Example 2: A "stacked chip" package. Total die area 12 cm2. GWP per "stacked chip" package = CO2e/die area in cm2 × 12 + CO2e/piece "stacked chip" package type back-end process. + +Example of alternative assessment, FCBGA1024 package. Die area 2.8 cm2. Mass 12.6 grams. + +GWP per FCBGA1024 = 2.8 cm2 × kg CO2e/(cm2×masklayer) × 1/front-end yield × mask layers for technology node (Scope 1,2,3 front-end) + 0.0126 kg × 1/back-end yield × kg CO2e/kg IC (Scope 1,2,3 back-end). + +Example of alternative assessment, SOIC 8 package. Die area not yet available. Mass 0.08 grams. + +GWP per SOIC8 = 0.00008 kg × kg CO2e/kg IC (Scope 1,2,3 front-end and back-end, considering front-end and back-end yields). + +NOTE 4 – Example: CO2e for a liquid crystal display (LCD) in a mobile phone, active area 33 cm2 = CO2e/active area display module in cm2 (mobile phone displays) × 33 cm2 + CO2e/piece display panel (mobile phone display panels) × 1 piece. + +NOTE 5 – Relates to transport. + +NOTE 6 – The use of black box module data for ICT goods in a study needs to be transparently justified and reported with respect to compliance to this Recommendation. Example: A network operator may use black box module data for a set-top box, a mobile phone manufacturer may use black box module data for a camera, a data centre operator may use black box module data for uninterruptible power supply (UPS) and they need to report the compliance of this data to this Recommendation and motivate any deviation. + +NOTE 7 – Piece as product flow unit (allocation basis) is applicable if the part factory produces one unique part type. + +NOTE 8 – It is acceptable to consider the battery as a black box. + +## Annex F + +### EoLT processes + +(This annex forms an integral part of this Recommendation.) + +Table F.1 below defines, for ICT goods, the different specific EoLT processes which shall be included (if applicable to the goal and scope and studied product system). Mandatory process categories and corresponding EoLT processes are listed in the table for each EoLT process. The list is to be regarded as a minimum mandatory list, and more EoLT processes/process categories/unit processes may be included. Usually, D3 Other EoLT consists of combinations of G6.1 and G6.2. + +NOTE – At the time of publication, some of the requirements in Annex F are considered as challenging due to LCA tool limitations, lack of data, limitations in data granularity, etc. It is thus recognized that compliance to all requirements in Annex F may not be possible at the time this Recommendation is published. + +Deviation(s) from the requirements shall be clearly motivated and reported. + +**Table F.1 – EoLT processes for LCA of ICT goods** + +| | Process categories | EoLT process unit processes (for each category) | Goods flow unit | Important issues | +|---------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------|-----------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| D. EoLT | D1. Preparation for extended operating lifetime
D2. ICT-specific EoLT
D2.1 Storage/Disassembly/Dismantling/Shredding
D2.2 Recycling
D2.2.1 Battery recycling
ICT-specific metal/mechanical parts/fractions EoLT
D2.2.2 PCBA recycling
D2.2.3 Cable recycling
D2.2.4 Mechanics recycling
D2.2.5 Other ICT recycling
D3. Other EoLT | Recycling, recovery and treatment | Piece/mass | In case of reuse and refurbishment, "D1 preparation of ICT goods for extended operating lifetime" includes a decision point where the ICT good is checked if it should proceed to next life with reuse, refurbishment or proceed with recycling and other EoLT processes. The refurbishment process falls under "B1 ICT goods production" for next life of the ICT goods. | + +## Annex G + +### Elementary flows (emissions and resources) + +(This annex forms an integral part of this Recommendation.) + +A list of elementary flows in LCAs of ICT is given in Table G.1. + +Table G.1 contains elementary flows which shall be taken into account in LCA analyses for ICT. More flows could be relevant, and the list refers to the mandatory LCI flows. The most commonly used name, chemical name or abbreviation has been put first followed by other common names/abbreviations. The substance names listed in Table G.1 shall be used in the report. + +For an appropriate reporting format refer to Annex L (Table L.9). + +NOTE – At the time of publication, some of the requirements in Table G.1 are considered as challenging. It is thus recognized that compliance to these requirements may not be possible at the time this Recommendation is published. + +Deviation(s) from the requirements shall be clearly motivated and reported. + +The unit is mass (unless stated otherwise): g, kg, and tonne. + +**Table G.1 – Elementary flows in LCAs of ICT** + +| Inventory | | | +|------------------------------------------------------------------|--------------|------------------------------------------------------------------------------| +| Substance | Measure unit | Contribution to midpoint impact assessment Category(ies) (Table 5, clause 8) | +| Aluminium (resource) | kg | RDMR, LU | +| Ammonia (to air) | kg | A | +| As (to air) | kg | HTC, ETFW | +| As (to water) | kg | HTC, ETFW | +| As (to soil) | kg | HTC, ETFW | +| Benzene (to air) | kg | HTC, ETFW | +| Biochemical oxygen demand (BOD) (to water) | kg | EA | +| Cd (to air) | kg | HTC, ETFW | +| Cd (to water) | kg | HTC, ETFW | +| Cd (to soil) | kg | HTC, ETFW | +| Cr (to water) | kg | HTC, ETFW | +| Cr (to soil) | kg | HTC, ETFW | +| CClF 3 , (CFC-13) (to air) | kg | OD, CC | +| CCl 3 F, (CFC-11) (to air) | kg | OD, CC | +| CCl 2 F 2 , (CFC-12) (to air) | kg | OD, CC | +| Cl 2 FC-CClF 2 , (CFC-113) (to air) | kg | OD, CC | +| C 2 F 6 (CFC-116) (to air) | kg | OD, CC | +| C 2 H 2 F 4 , HFC-134a (to air) | kg | OD, CC | +| C 2 H 3 F 3 , HFC-143a (to air) | kg | OD, CC | + +**Table G.1 – Elementary flows in LCAs of ICT** + +| Inventory | | | +|---------------------------------------------------------------------|--------------|------------------------------------------------------------------------------| +| Substance | Measure unit | Contribution to midpoint impact assessment Category(ies) (Table 5, clause 8) | +| C 2 H 1 F 5 , HFC-125 (to air) | kg | OD, CC | +| C 2 H 3 Cl 2 F, HCFC-141b (to air) | kg | OD, CC | +| CF 2 ClBr, Halon 1211 (to air) | kg | OD, CC | +| CF 3 Br, Halon 1301 (to air) | kg | OD, CC | +| CF 4 , CFC-14 (to air) | kg | OD, CC | +| CH 3 Cl 3 , HCFC-140 (to air) | kg | OD, CC | +| CH 4 , Methane (to air) | kg | CC | +| CHF 2 Cl, HCFC-22 (to air) | kg | OD, CC | +| CHF 3 , HFC-23 (to air) | kg | OD, CC | +| Cl - (to water) | kg | HTNC, ETFW, A | +| Cl - (to soil) | kg | HTNC, ETFW, A | +| CO, Carbon monoxide (to air) | kg | HTNC, POF, CC | +| CO 2 (to air) | kg | CC, A | +| Coal (resource) | kg, TOE, MJ | RDMR, LU | +| Copper (resource) | kg | RDMR, LU | +| Copper (to air) | kg | HTNC, ETFW | +| Copper (to water) | kg | HTNC, ETFW | +| Chemical oxygen demand (COD) (to water) | kg | EA | +| EHW = Environmental hazardous (waste) | kg | LU | +| EHW Ashes, special EHW landfill (waste) | kg | LU | +| EHW Metal hydroxides (MeOH), special EHW landfill (waste) | kg | LU | +| EHW Slag, special EHW landfill (waste) | kg | LU | +| Ethylene (air) | kg | POF | +| Ethylene oxide (air) | kg | HTNC, ETFW | +| Formaldehyde, CH 2 O (to air) | kg | HTC, POF | +| Gas (resource) | kg, TOE, MJ | RDMR, LU | +| Gold (resource) | kg | RDMR, LU | +| Hg (to air) | kg | HTC, ETFW | +| Hg (to water) | kg | HTC, ETFW | +| Hg (to soil) | kg | HTC, ETFW | +| Hydrogen chloride (to air) | kg | A, HTNC | +| Iron (to air) | kg | HTNC | +| Iron (resource) | kg | RDMR | +| Iron (to water) | kg | HTNC | + +**Table G.1 – Elementary flows in LCAs of ICT** + +| Inventory | | | +|-----------------------------------------------------------|----------------------|---------------------------------------------------------------------------------| +| Substance | Measure unit | Contribution to midpoint impact assessment Category(ies)
(Table 5, clause 8) | +| Iron (to soil) | kg | HTNC | +| Land occupation, agricultural | m 2 ×year | LU | +| Land occupation, urban | m 2 ×year | LU | +| Metals (unspecified) (to water) | kg | HTNC, HTC, ETFW | +| Metals (unspecified) (to soil) | kg | HTNC, HTC, ETFW | +| Mineral (waste) | kg | LU | +| Mo (to water) | kg | HTNC, ETFW | +| Mo (to soil) | kg | HTNC, ETFW | +| N 2 O (to air) | kg | CC, OD | +| NF 3 (to air) | kg | CC, OD | +| Nickel (resource) | kg | RDMR, LU | +| Nickel (to water) | kg | HTNC, ETFW | +| Nickel (to soil) | kg | HTNC, ETFW | +| N-total (to water) | kg | EA, ET | +| Nitrate, NO 3 - (to water) | kg | EA | +| NMVOC, non-methane volatile organic compounds (to air) | kg | POF, RI/PM, HTNC | +| NMHC, non-methane hydrocarbons (to air) | kg | HTNC, HTC, POF | +| NO x (to air) | kg | CC, EA, ET, POF, HTNC, ETFW | +| Oil (to soil) | kg | HTC | +| Oil (resource) | kg, TOE, MJ | RDMR, LU | +| Oil (to water) | kg | HTC | +| Other CFCs/HFCs/HCFCs/PFCs (to air) | kg | OD, CC | +| Other (new) "high GWPs/ODPs" (to air) | kg | OD, CC | +| Polycyclic aromatic hydrocarbon (PAH), all kinds (to air) | kg | HTC | +| Palladium (resource) | kg | RDMR, LU | +| Platinum(resource) | kg | RDMR | +| Particulates, all kinds (to water) | kg | HTC, HTNC, ETFW | +| Particulates, all kinds (to air) | kg | CC, HTC, ETFW, POF, RI/PM | +| Pb (resource) | kg | RDMR | +| Pb (to air) | kg | HTNC, ETFW | +| Pb (to water) | kg | HTNC, ETFW | +| Pb (to soil) | kg | HTNC, ETFW | + +**Table G.1 – Elementary flows in LCAs of ICT** + +| Inventory | | | +|-----------------------------------------------------|----------------|------------------------------------------------------------------------------| +| Substance | Measure unit | Contribution to midpoint impact assessment Category(ies) (Table 5, clause 8) | +| PF 3 (to air) | kg | CC, OD | +| Phosphate, PO 4 3- (to water) | kg | EA, ET | +| P-total (to water) | kg | EA, ET | +| Radioactive (low, volume) (waste) | kg | IRH, IRE | +| Radioactive (medium, volume) (waste) | kg | IRH, IRE | +| Radioactive (high, volume) (waste) | kg | IRH, IRE | +| Selenium (to water) | kg | HTNC, ETFW | +| Selenium (to soil) | kg | HTNC, ETFW | +| Silver (resource) | kg | RDMR, LU | +| Solid waste to landfill (waste) | kg | LU | +| SF 6 (to air) | kg | CC, OD | +| SO 2 (to air) | kg | A, POF, HTNC, ETFW, RI/PM | +| SO x (to air) | kg | A, POF, HTNC, ETFW, RI/PM | +| TCDD e ("Dioxin" equivalents) (to air) | kg | HTC | +| Tin (resource) | kg | RDMR | +| Titanium (to water) | kg | HTNC, ETFW | +| Titanium (to soil) | kg | HTNC, ETFW | +| Toluene (to air) | kg | POF, HTC, HTNC | +| Uranium (resource) | kg, MJ, TOE | RDMR | +| Water, lake (resource) | m 3 | RDW | +| Water, river (resource) | m 3 | RDW | +| Water, well, in soil (resource) | m 3 | RDW | +| Water, unspecified, natural origin (resource) | m 3 | RDW | +| Zinc (to water) | kg | HTNC, ETFW | +| Zinc (resource) | kg | RDMR | +| Zinc (to soil) | kg | HTNC, ETFW | +| Zinc (to air) | kg | HTNC, ETFW | + +The recommended unit is mass (unless otherwise stated): g, kg, tonne. + +For global warming potential factors, refer to the latest IPCC information available, at the time of publication this Recommendation [b-IPCC]. + +Other elementary flows which are of interest may be added when enough scientific consensus is available. + +For energy the following resources shall apply: + +- oil + +- gas +- coal +- uranium +- energy related to hydro-electric power +- biofuels +- for renewable energy sources use generated energy. + +Different qualities of fossil fuels have different contents of C/H (coal/hydrogen), and then also different energy content measured in kgOE or total oil equivalent (TOE) or megajoule (MJ). + +The recommended unit is kgOE, TOE (kg or tonne oil equivalents) or MJ. + +## Annex H + +### List of raw materials + +(This annex forms an integral part of this Recommendation.) + +Table H.1 lists the minimum raw material *groups* (chemicals, fuels, metals, plastics, packaging materials, and additives) which shall be taken into account in LCAs of ICT goods, if applicable to the studied ICT product system. + +Table H.1 would be too long if all specific materials were listed, as there are many variants of each chemical, fuel, metal and alloy, plastic and additives. Therefore, each material name in Table H.1 refers to a *group* of raw materials and not specific chemical abstracts service (CAS) code materials. + +These raw material *groups* are either part of the material content of the ICT goods/support goods or used as ancillary materials throughout the life cycle. + +**Table H.1 – Cradle-to-gate groups of raw materials to be included in LCA of ICT goods** + +| Chemicals | Metals and alloys | +|--------------------------------|----------------------------------------------------| +| Nitrogen gas (N 2 ) | Aluminium | +| Oxygen gas (O 2 ) | Brass | +| Hydrogen gas (H 2 ) | Bronze | +| Argon gas (Ar) | Cadmium | +| Acetone | Chromium | +| CaO | Copper | +| H 2 SO 4 | Gallium | +| H 2 O 2 | Gold | +| HydroChloric Acid (HCl) | Indium | +| FeCl 3 | Lead | +| IsoPropyleneAlcohol | Lithium | +| Ethylene glycol | Magnesium | +| HydroFluoric acid | Mercury | +| H 3 PO 4 | Nickel | +| HNO 3 | Palladium | +| NaOH | Platinum | +| | Silicon | +| | Silver | +| Fuels | Solder – Sn/Ag/Cu alloys (SAC) (tin silver copper) | +| Heating oil | Solder – Sn/Pb | +| Bunker oil / ship diesel | Solder – SnZn | +| Diesel | Steel – Cr 3+ plated | +| Petrol | Steel – powder coated | +| Jet fuel | Steel – zinc plated | +| LPG | Steel – stainless steel | +| LNG | Tin | + +**Table H.1 – Cradle-to-gate groups of raw materials to be included in LCA of ICT goods** + +| Chemicals | Metals and alloys | +|----------------------------------------------------|---------------------------------------------------------| +| "Biofuels" | Zinc | +| For renewable energy sources use generated energy. | Hard metal (W-Co) | +| Uranium | | +| Energy related to hydro-electric power | | +| | | +| Plastics | Others | +| Acrylonitrile butadiene styrene (ABS) | Concrete | +| Epoxy | Packaging materials | +| Polycarbonate (PC) | Ceramics | +| Polyethylene (PE) – high density (HD) | Paper | +| Polyethylene (PE) – low density (LD) | Cardboard | +| Polypropylene (PP) | Wood | +| Polystyrene (PS) | Wood board | +| Polyurethane (PUR) | Glass | +| Polyester (e.g., polyethylene terephthalate (PET)) | Glass fibre | +| Polyvinyl chloride (PVC) | | +| Silicone rubber | Additives and others | +| Styrene acrylonitrile (SAN) | Paper additives | +| Polyamide (PA) (Nylon) | Plastic additives | +| Polytetrafluoroethylene (PTFE) (Teflon) | High purity grades of materials/chemicals and gases | +| Polymethyl methacrylate (PMMA) | Cooling media, fire extinguisher media (high GWPs/ODPs) | +| | | + +Different qualities of fossil fuels have different contents of C/H (coal/hydrogen), and then also different energy content measured in kgOE or TOE or MJ. + +The recommended unit is kgOE, TOE (kg or tonne oil equivalents) or MJ. + +## Annex J + +### ICT network overview + +(This annex forms an integral part of this Recommendation.) + +An ICT network is commonly described in terms of boxes, each of which is associated with a specific function or a set of coherent functions. Typically, major network functions could be represented as shown below. The network elements depicted in Figure J.1 are part of existing ICT networks and shall be studied when defining the studied product system. However, this Recommendation is not restricted to these ICT network elements but will also apply when assessing any existing or future ICT networks. + +![Figure J.1 – Example of an ICT network reference model. The diagram shows four main network domains: Wireless access and core, Enterprise fixed access, Residential fixed access, and a shared Metro/Edge and Core network. Wireless access and core includes eNB (LTE), Node B (Back-haul, CDMA), Femto, and their respective core components (MME, S-GW, P-GW, RNC, SGSN, GGSN, MMC, OM, Pkt Sw, Secur. GW). Enterprise fixed access includes Access switch, Aggregation switch, Core Sw, and Firewall/WAN. Residential fixed access includes ADSL + GWY, DSLAM, VDSL + GWY, DSLAM + ONU, OLT, ONU, SPLIT, and OLT. The Metro/Edge network includes Ethernet switch, ROADM, and Metro router. The Core network includes Core router, ROADM, and OTN. Arrows indicate data and voice flows between these components.](e26bb66586e464339df27951d5c9355e_img.jpg) + +The diagram illustrates an ICT network reference model with four main domains: + +- Wireless access and core:** This domain is split into two main paths. The top path for LTE includes eNB (LTE) connected to MME, S-GW, and P-GW, which then connects to Data. The bottom path for CDMA includes Node B (Back-haul) connected to RNC, SGSN, and GGSN, which then connects to Data and Voice. A Femto unit is connected to Fixed access back-haul, which is connected to Secur. GW. Another path shows Node B (CDMA) connected to MMC, OM, and Pkt Sw, which then connects to Data. +- Enterprise fixed access:** This domain includes Access switch, Aggregation switch, Core Sw, and Firewall/WAN. +- Residential fixed access:** This domain includes ADSL + GWY connected to DSLAM, VDSL + GWY connected to DSLAM + ONU and OLT, and ONU connected to SPLIT and OLT. +- Metro/Edge network and Core network:** These two domains are shown together. The Metro/Edge network includes Ethernet switch, ROADM, and Metro router. The Core network includes Core router, ROADM, and OTN. Arrows indicate data flows between these components and the other domains. + +Figure J.1 – Example of an ICT network reference model. The diagram shows four main network domains: Wireless access and core, Enterprise fixed access, Residential fixed access, and a shared Metro/Edge and Core network. Wireless access and core includes eNB (LTE), Node B (Back-haul, CDMA), Femto, and their respective core components (MME, S-GW, P-GW, RNC, SGSN, GGSN, MMC, OM, Pkt Sw, Secur. GW). Enterprise fixed access includes Access switch, Aggregation switch, Core Sw, and Firewall/WAN. Residential fixed access includes ADSL + GWY, DSLAM, VDSL + GWY, DSLAM + ONU, OLT, ONU, SPLIT, and OLT. The Metro/Edge network includes Ethernet switch, ROADM, and Metro router. The Core network includes Core router, ROADM, and OTN. Arrows indicate data and voice flows between these components. + +Figure J.1 – Example of an ICT network reference model + +A wireless access and core network consists of an access and a core domain. Examples of wireless technologies include global system for mobile communications (GSM), W-CDMA, long term evolution (LTE). Typically, for LTE/EPC the core network (known as the evolved packet system) provides Internet protocol (IP) connectivity using the access network (E-UTRAN). For GSM and UMTS, the core network consists of a circuit-switched domain (comprising mobile switching centre (MSC)/VLR) and a packet-switched domain (general packet radio service (GPRS), core comprising serving GPRS support node (SGSN), gateway GPRS support node (GGSN)), which supports interworking with IP-based networks. The mobile access network consists of physical entities which manage the radio resource (BTS/ base station control site (BSC), node B/RNC, enode B) and provide the user with mechanisms to access the core network. + +The residential fixed access network provides the end user with an access to the network carrying digital signals used for voice band and digital data. + +The metro/edge network provides connectivity and transport to large areas with a high concentration of business customers. These ICT networks provide the bridge between the long-haul environment and the access environment. + +The enterprise fixed access network includes a local area network (LAN) used to connect an end system to an edge router. There are many different types of LAN technology and Ethernet technology is currently by far the most prevalent access technology in enterprise networks. The edge router is then routing packets that have destinations outside of the LAN. + +The long-haul network interconnects cities and regions covering hundreds of kilometres between several central offices. It includes core routers operating in the Internet backbone and forwarding IP packets at a very high speed through optical transport infrastructures. + +From an end-user perspective, some other devices are used when they are offered as an end-to-end service. Typically, terminal devices (mobile phones, fixed phone sets, personal computers, printers, scanners) are needed to initiate a call, to surf the Internet or to print documents. GPS devices are also required to propose optimized routes when driving a vehicle. Moreover, it is expected that innovative services will be provided in the future to the general public that will drastically change the environmental impact of end users (such as smart meters for example). Also, enterprises are using a variety of goods for running their business (private branch exchange (PBX) switches, PC, printers, scanners). + +An example of the functions of a wireless mobile telecommunication network is shown below in Figure J.2. + +![Diagram of a wireless mobile telecommunication network architecture showing customer premises, access network equipment, and core network components.](a0eb8d30ac11ba97b2733c187b89ff22_img.jpg) + +The diagram illustrates the architecture of a wireless mobile telecommunication network. It is divided into three main sections: a) Customer premises, b) Access network equipment, and c) Core network. On the left, a 'Mobile station' (represented by a mobile phone icon) is connected to a 'Base station' (represented by a tower icon). The 'Base station' is connected to a 'Local switch'. This 'Local switch' is part of the 'Access network equipment' and is connected to a 'Gateway switch'. The 'Gateway switch' is connected to a 'Toll switch', which is part of the 'Core network'. The 'Toll switch' is connected to another 'Gateway switch', which is then connected to another 'Local switch'. This 'Local switch' is connected to another 'Base station', which is finally connected to another 'Mobile station' on the right. Above the 'Core network' section, there is a 'Server' connected to two 'Gateway' units, which are in turn connected to the 'Gateway switch' units. The diagram is labeled with 'L.1410(14)\_FJ.2' in the bottom right corner. + +Diagram of a wireless mobile telecommunication network architecture showing customer premises, access network equipment, and core network components. + +**Figure J.2 – Example of functions of wireless mobile telecommunication network** + +## Annex K + +### A method for assessing the environmental load of the working environment + +(This annex forms an integral part of this Recommendation.) + +This annex describes a methodology to assess the environmental load of the working environment. + +- This methodology shall be studied for assessing the working environment related impacts related to ICT goods, networks and services (Part I, clause 7). +- It may also be used to assess the impacts related to the working environment when performing a comparison implying better office space usage thanks to ICT (Part II, clause 12). + +An example of an assessment of the environmental impact of the working environment based on this methodology is provided in Appendix X. + +### K.1 Purpose of targeting the working environment in the assessment of ICT goods, networks and services + +The working environment is one of the important checklist items to consider when assessing the environmental impact of ICT goods, networks and services in Part I. + +In addition, improved work efficiency thanks to ICT goods, networks and services is listed as a category for comparison in Part II. To perform a comparison, an assessment of the working environment is often necessary. + +Employment and work styles are undergoing a transformation in many countries and there are several types of office spaces in addition to the traditional ones, such as small offices home offices (SOHO), mobile office, etc. + +### K.2 Functional unit + +A functional unit of the "working environment" may be defined as a "provision of working space and working environment for one year". + +Another functional unit of the "working environment" may be defined as a "provision of working space and working environment for one year per person". + +### K.3 System boundary + +A system boundary for evaluating the working environment may be described as shown in Figure K.1. Once the functional unit is defined, energy consumption should be calculated by considering the energy consumption of the heating system, air conditioning system, other motive powers (e.g., for automatic doors, elevators), lighting and appliances used for business purposes and related to targeted work. As for other energy consumption data, GHG emissions should then be derived from the energy consumption values. + +![Figure K.1 – System boundary of working environment. A flowchart showing the life cycle of building and office appliance materials. The process is divided into four stages: Raw material acquisition, Production, Use, and EoLT. The top path shows building materials: Acquisition of building materials → Construction of building → Office space (Heating, Air conditioning, Lighting, Motive power, Office appliances) → Disposal/recycling of building materials. The bottom path shows office appliances: Acquisition of appliance and furniture materials → Manufacturing of appliances and furniture → Office space (same items) → Disposal/recycling of office appliances and furniture. The 'Use' stage for both paths is the 'Office space' box. The diagram is labeled L.1410(24) in the bottom right.](9687bd5e8b62cadba093b0d1b70536cd_img.jpg) + +``` + +graph LR + subgraph Raw_material_acquisition + A1[Acquisition of building materials] + A2[Acquisition of appliance and furniture materials] + end + subgraph Production + B1[Construction of building] + B2[Manufacturing of appliances and furniture] + end + subgraph Use + C[Office space: +- Heating +- Air conditioning +- Lighting +- Motive power +- Office appliances] + end + subgraph EoLT + D1[Disposal/recycling of building materials] + D2[Disposal/recycling of office appliances and furniture] + end + A1 --> B1 --> C --> D1 + A2 --> B2 --> C --> D2 + +``` + +L.1410(24) + +Figure K.1 – System boundary of working environment. A flowchart showing the life cycle of building and office appliance materials. The process is divided into four stages: Raw material acquisition, Production, Use, and EoLT. The top path shows building materials: Acquisition of building materials → Construction of building → Office space (Heating, Air conditioning, Lighting, Motive power, Office appliances) → Disposal/recycling of building materials. The bottom path shows office appliances: Acquisition of appliance and furniture materials → Manufacturing of appliances and furniture → Office space (same items) → Disposal/recycling of office appliances and furniture. The 'Use' stage for both paths is the 'Office space' box. The diagram is labeled L.1410(24) in the bottom right. + +**Figure K.1 – System boundary of working environment** + +### K.4 Life cycle inventory (LCI) + +#### K.4.1 Data collection + +To evaluate the energy consumption and GHG emissions of the working environment (whether at the office or at home), data on energy consumption, the space occupied by each person, and the number of working hours per year could be calculated based on available statistical data. + +#### K.4.2 Data calculation + +Regarding the environmental impact of the working environment, energy consumption should first be assessed for all activities within the system boundaries, e.g., heating, air conditioning, lighting, motive power, etc. + +NOTE – Depending on the type of data available (aggregated or distributed), classification into these activities may not be applicable. + +Secondly, energy consumption should be classified into fuel categories in accordance with Annex H. + +Thirdly, energy consumption and GHG emissions should be calculated for each fuel category in: + +- Energy (J) +- GHG emission (kg-CO2e). + +Finally, total energy consumption and GHG emissions should be calculated by adding the environmental impact of all fuel categories. + +#### K.4.3 Allocation procedure + +To evaluate energy consumption and GHG emissions of offices at home, an allocation between working activities and other activities is required. This distinction between working activities and other activities should be based on appropriate assumptions and should be documented. + +Overall, publicly available statistical data to be considered for allocation in a home office: + +- working style +- working hours +- percentage of workers who work only at home or at home and at the office. + +Considering the above-mentioned factors, the home office impact intensity would be obtained by allocating the environmental load to the working activities and household activities. + +## Annex L + +### Reporting formats + +(This annex forms an integral part of this Recommendation.) + +This annex contains tables that shall be used to report the result of the assessment. + +NOTE – In line with indications in the main text related to LCA tool limitations, etc., at the time of publication, it may be challenging to fulfil fully certain reporting tables included in this annex. It is thus recognized that compliance to all reporting requirements may not be possible at the time this Recommendation is published. Deviation(s) from the requirements shall be clearly motivated and reported. + +**Table L.1 – Cover page** + +| REPORTING | | | | +|----------------------------------------------------|-----|----|------------------------------------| +| | Yes | No | Description/references to page | +| General information | | | | +| Company name and contact information | | | | +| Project name | | | | +| Product system | | | | +| Product system related information | | | | +| Product system function | | | | +| Product system description | | | | +| Product picture (optional) | | | | +| Date of completion of assessment (DD/MM/YYYY) | | | | +| Compliant with ITU-T L.1410 most recent version | | | | +| LCA tool used | | | | +| External review (yes/no) | | | | +| Reviewers | | | | +| Goal definition | | | | +| Reason for carrying the study | | | | +| Target audience(s) | | | | +| Comparative assessment | | | | +| Scope definition | | | | +| Functional unit | | | | +| Reference flow | | | | +| System boundaries | | | | +| Environmental impact categories | | | | +| List of optional and recommended stages considered | | | | +| Cut-off criteria | | | | + +**Table L.1 – Cover page** + +| REPORTING | | | | +|--------------------------------------------------------------------|--|--|--| +| Resource used and emission profile | | | | +| Secondary data sources | | | | +| Data collection procedure | | | | +| Technical process flow diagram | | | | +| Unit process description | | | | +| Calculation procedure | | | | +| Allocation procedure including the handling of multi functionality | | | | +| Data quality | | | | +| Data gap | | | | +| Environmental impact assessment | | | | +| Assessment results | | | | +| Normalization (optional) | | | | +| Weighting (optional) | | | | +| Interpretation | | | | +| Uncertainty aspects including results from sensitivity analyses | | | | +| Conclusion including identification of hot spots | | | | + +**Table L.2 – Reporting format for included life cycle stages, activities and generic processes** + +| Tag | Life cycle stage/
Process | Unit process | Included (Yes/No) | Electricity mix (specific/
country/
world average) | Support activities included (Yes/No) | Transport activities included (Yes/No) G1 | Other generic activities included (Yes/No) G2-7 | Motivation/Comment | +|------------|--------------------------------------|---------------------------------------------------------|--------------------------|-------------------------------------------------------------------|---------------------------------------------|--------------------------------------------------|--------------------------------------------------------|---------------------------| +| A | Goods Raw Material Acquisition | | | | | | | | +| A1 | Raw material extraction | | | | | | | | +| A2 | Raw material processing | | | | | | | | +| B | Production | | | | | | | | +| B1 | ICT goods production | | | | | | | | +| B1.1 | | Parts production (for further details refer to Annex E) | | | | | | | +| B1.2 | | Assembly | | | | | | | + +**Table L.2 – Reporting format for included life cycle stages, activities and generic processes** + +| Tag | Life cycle stage/
Process | Unit
process | Included
(Yes/No) | Electricity
mix
(specific/
country/
world
average) | Support
activities
included
(Yes/No) | Transport
activities
included
(Yes/No)
G1 | Other
generic
activities
included
(Yes/No)
G2-7 | Motiva-
tion/Com-
ment | +|------|---------------------------------------------------------|-------------------------------------------------------|----------------------|-------------------------------------------------------------------|-----------------------------------------------|-------------------------------------------------------|----------------------------------------------------------------|------------------------------| +| B1.3 | | ICT
manufacturer
support
activities | | | | | | | +| B2 | Support
goods
production | | | | | | | | +| B2.1 | | Support
goods
manufactu-
ring | | | | | | | +| B3 | ICT-
specific
site
construc-
tion | | | | | | | | +| C | Use | | | | | | | | +| C1 | ICT goods
use | | | | | | | | +| C2 | Support
goods use | | | | | | | | +| C3 | Operator
support
activities | | | | | | | | +| C4 | Service
provider
support
activities | | | | | | | | +| D | Goods end-of-life treatment | | | | | | | | +| D1 | Preparation
for
extended
operating
lifetime | | | | | | | | +| D2 | ICT-
specific
EoLT | | | | | | | | +| D2.1 | | Storage/
Disassembly/
Dismantling/
Shredding | | | | | | | +| D2.2 | | Recycling | | | | | | | +| D3 | Other
EoLT | | | | | | | | + +**Table L.3 – Reporting format for generic processes for LCAs of ICT goods** + +| Generic process | Generic process categories included (see Note 1) | Unit processes included (for each generic process category) (see Note 1) | Important issues (see Note 2) | +|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------|---------------------------------------------------------------------------------|--------------------------------------------------------------| +| G1. Transport and travel | | | E.g., clarify comprehensiveness of the used emission factors | +| G2. Electricity | | | E.g., clarify comprehensiveness of the used emission factors | +| G3. Fuels | | | E.g., clarify comprehensiveness of the used emission factors | +| G4. Other energy | | | E.g., clarify comprehensiveness of the used emission factors | +| G5. Raw material acquisition | | | | +| G6. End-of-life treatment | | | | +| G7. Raw material recycling | | | | +| NOTE 1 – Annex D gives examples of generic process categories and unit processes to be included if applicable.
NOTE 2 – Include description of data source for each generic process category, e.g., from commercial LCI databases. | | | | + +**Table L.4 – Reporting format for transport/travel** + +| Mode | CO 2 e emission factor (see Note 3) | Raw material acquisition transport | | Production stage transport excluding final transport | | Final transport (see Note 1) (production to use stage) | | Use stage transport | | EoLT transport | | Total transport | | Total travel (see Note 5) | | +|---------------------|------------------------------------------------|-----------------------------------------|--------------------------------------------|------------------------------------------------------|-------------------------------|--------------------------------------------------------|-------------------------------|----------------------------|--------------------------------|----------------------------|--------------------------------|--------------------------------------|-------------------------------|---------------------------|-------------------------------| +| | | Transport work (see Note 2) {tonne× km} | GWP100 {kg CO 2 e} (see Note 6) | Transport work {tonne× km} | GWP100 {kg CO 2 e} | Transport work {tonne× km} | GWP100 {kg CO 2 e} | Transport work {tonne× km} | GWP 100 {kg CO 2 e} | Transport work {tonne× km} | GWP 100 {kg CO 2 e} | Transport distance (see Note 2) {km} | GWP100 {kg CO 2 e} | Travel distance {km} | GWP100 {kg CO 2 e} | +| Air | | | | | | | | | | | | | | | | +| Other1 (see Note 4) | | | | | | | | | | | | | | | | +| Other2 (see Note 4) | | | | | | | | | | | | | | | | + +NOTE 1 – The final transport of ICT goods from assembly to operator, including pre- and post-transport connected to the main transport. +NOTE 2 – Average in terms of distance, transport mode, load factor, chargeable mass, etc. +NOTE 3 – This includes direct fuel consumption and also fuel supply chain. +NOTE 4 – Specify used transport mode. +NOTE 5 – Includes all kinds of travel throughout life cycles, e.g., commuting, business travel and maintenance travel when applicable. Specify travels taken into account. +NOTE 6 – Other impact categories to be added as applicable. + +**Table L.5 – Reporting format for raw materials** + +| | Total input (g, kg, tonne) | Content in product (%) (see Note 1) | Recycled raw material used (see Note 2) (%) | Recycling of total input (see Note 3) (%) | Reference | +|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------|--------------------------------------------|----------------------------------------------------|--------------------------------------------------|------------------| +| Iron/Steel alloys | | | | | | +| Aluminium alloys | | | | | | +| Copper alloys | | | | | | +| Silver | | | | | | +| Gold | | | | | | +| ICT product system raw materials (optional) | | | | | | +| Raw material 1 | | | | | | +| Raw material ... | | | | | | +| Raw material n | | | | | | +| Auxiliary raw materials (production materials, etc.) (optional) | | | | | | +| Auxiliary material 1 | | | | | | +| Auxiliary material ... | | | | | | +| Auxiliary material n | | | | | | +| Packaging materials(optional) | | | | | | +| Packaging material 1 | | | | | | +| Packaging material ... | | | | | | +| Packaging material n | | | | | | +| NOTE 1 – Percentage of total input material present in the product after the production process, i.e., total input minus the related production waste. | | | | | | +| NOTE 2 – The amount of recycled raw material used in the production process, this includes the raw material contained in the product and the related production waste. | | | | | | +| NOTE 3 – Total recycling of all input materials, i.e., recycling of manufacturing waste and recycling of total content in final product during end-of-life (EOL). | | | | | | +| NOTE 4 – The reporting format of Table L.5 may not be easily supported by LCA tools and due to lack of data. In this case the LCA practitioner may report the raw material usage differently, e.g., based on the material content declaration of the ICT equipment instead of the total input. However, all deviations from the reporting format of Table L.5 must be outlined and motivated. | | | | | | + +For a full list of materials that could optionally be reported in Table L.5, refer to Annex H. + +**Table L.6 – Reporting format for parts production** + +| | Part categories included
(see Note 1) | Part unit processes included
(see Note 1) | Handling of special issues
(see Note 2) | +|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------|------------------------------------------------------|----------------------------------------------------| +| B1.1.1 Batteries | | | | +| B1.1.2 Cables | | | | +| B1.1.3 Electro-mechanics | | | | +| B1.1.4 Integrated circuits (ICs) | | | | +| B1.1.5 Mechanics/materials | | | | +| B1.1.6 Displays | | | | +| B1.1.7 Printed circuit boards (PCBs) | | | | +| B1.1.8 Other printed board assembly (PBA) components | | | | +| B1.1.9 Packaging materials | | | | +| B1.1.10 Black box modules | | | | +| NOTE 1 – Annex E gives a list of part categories and part unit processes which shall be included when applicable.
NOTE 2 – Include description of data source and data set for each part category, e.g., from commercial databases | | | | + +**Table L.7 – Reporting format for use stage energy consumption** + +| | Energy consumption {kWh/year} | Source {long term average/standardized measurement/modelled} | Motivation/comment | +|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------|---------------------------------------------------------------------|---------------------------| +| ICT goods | | | | +| Support goods | | | | +| NOTE – If the reporting above comes into conflict with confidentiality considerations, the data should be recorded internally and made available to potential third party peer reviewers. | | | | + +**Table L.8 – Reporting format for EoLT stage** + +| | Process categories included | Process unit processes included | Handling of special issues | +|---------------------------------------------------------------------------------------------------------------|------------------------------------|----------------------------------------|-----------------------------------| +| D1. Preparation for extended operating lifetime | | | | +| D2. ICT-specific EoLT | | | | +| D3. Other EoLT | | | | +| NOTE – Annex F gives a list of process categories and unit processes which shall be included when applicable. | | | | + +**Table L.9 – Reporting format for LCI results** + +| | TOTAL | Raw materials acquisition | Production | Use | EoLT | +|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------|----------------------------------|-------------------|------------|-------------| +| Primary energy use (Note 1) | | | | | | +| Total electricity use | | | | | | +| Land use (optional) | | | | | | +| Fresh water use (optional) (Note 2) | | | | | | +| LCI data 1(optional) | | | | | | +| LCI data ... (optional) | | | | | | +| LCI data n (optional) | | | | | | +| NOTE 1 – Primary energy usage is appropriate to express as 'Cumulative Energy Demand' (CED).
NOTE 2 – Fresh water refers to water from rivers, lakes, or subsoil water. | | | | | | + +**Table L.10 – Impact category indicators** + +| Midpoint category indicator | Impact category indicator value | LCIA methodology reference | +|------------------------------------|----------------------------------------|------------------------------------| +| Global warming potential | # kg CO 2 e | IPCC Climate Change 2013: [b-IPCC] | +| Etc. | | | + +**Table L.11 – Reporting format for network description** + +| | List of included ICT goods | List of included infrastructure | Quantity [unit] (see note) | Operating lifetime [year] | +|-------------------------------------------------------------------------------|-----------------------------------|----------------------------------------|-----------------------------------|----------------------------------| +| End-user goods and CPE | | | | | +| End-user goods | | | # [piece] | | +| CPE | | | # [piece] | | +| Operator Network and activities | | | | | +| Access network | | | # [sites] | | +| Control and core network | | | # [subscriber] | | +| Operator activities | | | # [employ] | | +| Data services | | | | | +| Data transport | | | # [gigabyte (GB)] | | +| Data centre(s) | | | # [GB] | | +| Service provider(s) activities | | | # [subscriber] | | +| NOTE – More appropriate units can be selected depending on the case analysed. | | | | | + +**Table L.12 – Reporting format for network energy consumption** + +| | ICT goods energy consumption | Support goods energy consumption | Source
{long term average/
standardized measurement/
modelled} | +|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------|-----------------------------------------|-----------------------------------------------------------------------------------| +| End-user goods and customer-premises equipment (CPE) | | | | +| End-user goods | | | | +| CPE | | | | +| Operator
Network and activities | | | | +| Access network | | | | +| Control and core network | | | | +| Operator activities | | | | +| Data services | | | | +| Data transport | | | | +| Data centre(s) | | | | +| Service provider(s) activities | | | | +| NOTE – If the reporting above comes into conflict with confidentiality considerations, the data should be recorded internally and made available to potential 3rd party peer reviewers. | | | | + +**Table L.13 – Reporting format for service hardware allocation** + +| End-user goods and
CPE | Allocation method | Allocation
of use
stage [%] | Allocation
of all non-use
stages [%] | +|------------------------------------|--------------------------|---------------------------------------------------|-----------------------------------------------------| +| End-user goods and CPE | | | | +| End-user goods | | | | +| CPE | | | | +| Operator network
and activities | | | | +| Access network | | | | +| Control and core network | | | | +| Operator activities | | | | +| Data services | | | | +| Data transport | | | | +| Data centre(s) | | Specific data centre(s) data
mandatory | | +| Service provider(s) activities | | Specific service provider(s)
data
mandatory | | + +## **Appendix I** + +### **Void** + +NOTE – For the former content of Appendix I, please refer to [b-ITU-T L-Suppl.60]. + +## Appendix II + +### Life cycle stages overview + +(This appendix does not form an integral part of this Recommendation.) + +An overview figure showing the contents and connections between all life cycle stages are shown below in Figure II.1. + +![Flowchart of life cycle stages overview showing connections between Raw material acquisition, Production, Use, EoLT, and Generic processes.](6348f4fc8b3848158fcfbe85e26a731d_img.jpg) + +The diagram illustrates the flow and connections between various life cycle stages for ICT equipment. It begins with an external 'Input from other life cycle' leading to 'A. Raw material acquisition', which includes 'A1. Raw material extraction' and 'A2. Raw material processing'. This stage connects via three downward arrows to 'B. Production'. 'B. Production' is divided into 'B1. ICT equipment production' (with sub-stages 'B1.1 Parts production B1.1.1 – B1.1.11', 'B1.2 Assembly', and 'B1.3 ICT manufacturing support activities'), 'B2. Support equipment production' (with 'B2.1 Support equipment manufacturing'), and 'B3. ICT specific site construction'. Arrows lead from 'B1.2 Assembly' and 'B2.1' to 'C. Use'. 'C. Use' includes 'C4. Service provider activities', 'C3. Operator activities', 'C1. ICT equipment use', and 'C2. Support equipment use'. A box 'D1. Prep. for reuse of ICT equipment' is positioned between 'C. Use' and 'D. EoLT', with arrows pointing to it from 'C1' and 'C2', and from it to 'D2.1'. 'D. EoLT' includes 'D2. ICT-specific EoLT' (with sub-stages 'D2.1 Storage/disassembly/dismantling/shredding', 'D2.2 Recycling', 'D2.2.1 Battery recycling', 'D2.2.2 PCA recycling', 'D2.2.3 Cable recycling', 'D2.2.4 Mechanics recycling', and 'D2.2.5 Other ICT recycling') and 'D3. Other EoLT'. Arrows lead from 'D2.2' and 'D3' to 'G. Generic processes' (specifically 'G7. Raw material recycling'), which then leads to 'Output to other life cycle'. Another 'G. Generic processes' box is located above 'D. EoLT', containing 'G1. Transport and travel', 'G2. Electricity supply', 'G3. Fuel supply', 'G4. Other energy supply', and 'G5. Raw material acquisition'. Arrows lead from this box to 'A. Raw material acquisition' and 'D. EoLT'. A third 'G. Generic processes' box is at the bottom, containing 'G6. EoLT', 'G6.1 EHW treatment', and 'G6.2 Other waste treatment', with an arrow leading from 'G6. EoLT' to 'D. EoLT'. A legend at the bottom left shows a right-pointing arrow labeled 'Transport'. + +Flowchart of life cycle stages overview showing connections between Raw material acquisition, Production, Use, EoLT, and Generic processes. + +L.1410(14)\_FII.1 + +Figure II.1 – Connection between all life cycle stages + +## Appendix III + +### Examples of goods and black box modules + +(This appendix does not form an integral part of this Recommendation.) + +This list summarizes entities frequently used in LCAs of ICT. The list is not a complete set of ICT goods but is rather an example to indicate the broad range of applicable ICT goods and support goods to be considered. + +Each goods type may be further divided into more specific goods types. + +### III.1 End-user goods + +Mobile phone or standard mobile phone + +Smartphone + +Tablet device (phone/e-reader/PC) + +Net book PC + +Laptop PC + +Desktop PC + +TV + +Any device that can connect to home or networks. + +### III.2 CPE + +Fixed wireless terminal (FWT, typically 1 3G+ in and 4 LAN + wireless local area network (WLAN) out) + +Modem + +Router (Typically 1 wide area network (WAN) in and 4 LAN + WLAN out) + +IPTV box and/or set-top box (STB) for IPTV + +Combo products (e.g., a 3-play or home gateway box: modem/router/IPTV) + +Fibre access (optical network unit (ONU)) and combo products including fibre access. + +### III.3 Network site goods (from base station sites to data centres) + +Base station goods + +Transmission goods (e.g., STM-1, radio link) + +Radio Access Networks (RAN) control and core goods (BSC, radio network controller (RNC), SGSN, GGSN, home location record (HLR), MSC, etc.) + +Fixed access node (FAN) goods (POTS, xDSL, FTTx/ optical line terminal (OLT)) + +Telecom switches and telecom servers (services) + +Edge/Metro routers/switches + +Core routers/switches + +Optical high-capacity transport goods (wavelength division multiplexer (WDM)) + +Servers + +Data switches + +Storage array network goods. + +### **III.4 Examples of ICT-specific black box modules** + +Cable set/module (cable + connectors) + +Memory module + +Camera module + +Display module + +Charger device + +Alternating current direct current (AC/DC) adapter incl. power cord + +Fan unit + +Hard disc drive + +Optical disc player + +Transceiver module + +Power amplifier module + +Power supply unit. + +### **III.5 Site support goods** + +NOTE – Some of these units are ICT specific; others have a more generic application. + +Antenna towers + +Antennas and feeders + +Lighting guides + +Buildings, shelters and other mechanical structures + +Diesel generators and tanks + +Rectifiers, UPS, battery + +Cooling system + +Monitoring system. + +## Appendix IV + +### Examples of networks and network goods + +(This appendix does not form an integral part of this Recommendation.) + +**Table IV.1 – Examples of networks** + +| Network type | Examples | +|----------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Access networks:
(see Note 1) | Fixed telephony (or POTS, plain old telephone system)
Fixed broadband access (digital subscriber line (DSL))
Mobile broadband access (2G (e.g., GSM), third generation telecom networks (3G) (e.g., WCDMA/HSPA), etc.) (see Note 2)
Cable access television (CATV) broadband
Fibre (FTTx) or City LAN
Enterprise LAN | +| Mobile control and core nodes | Control and core nodes for mobile
Control and core nodes for IPTV, voice over Internet protocol (VoIP), etc. | +| Data transport (see Note 3) | All other transmission (excluding transmission associated with the access nodes)
IP edge/metro/core network (switches and routers)
Submarine optical fibre cables and land terminal stations. | +| Data centres (see Note 4) | Servers, storage and network goods ("switches and routers")
Cooling, power and back-up power goods. | + +NOTE 1 – Including transmission between the access nodes, which is allocated to the access networks (e.g., plesiochronous digital hierarchy (PDH), synchronous digital hierarchy (SDH), wavelength division multiplexer (WDM) and network link elements like synchronous transport module (STM) /multiplexer (MUX), radio links and WDM elements and repeaters). + +NOTE 2 – The mobile control nodes which are in reality part of the access networks are in this physical view structured together with the core nodes as they often share sites. + +NOTE 3 – Data transport is a collective term used for all transmission and IP network goods that are used. + +NOTE 4 – The term data centre (s) can include all sizes of server networks, from enterprise data centres down to "a server in a closet". + +**Table IV.2 – Examples of network goods** + +| Network type | Access nodes | Infrastructure | Control and core nodes | +|-------------------------|------------------------------------------------------------------------------------------------|-------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------| +| POTS network | Remote subscriber switch (RSS), remote subscriber switch
Subscriber part of local exchanges | "Copper" cable network
Telecomm building/container | Local and higher order exchanges telephony and voice over internet protocol (VoIP) command and control (C&C) nodes | +| Fixed broadband network | Digital subscriber line access multiplexer (DSLAM) goods installed in POTS RSS/ | Reuse of POTS infrastructure | n.a. | + +**Table IV.2 – Examples of network goods** + +| Network type | Access nodes | Infrastructure | Control and core nodes | +|--------------------------------------------------------------|---------------------|----------------------------------------------|------------------------------------------------------| +| 2G mobile network | 2G base stations | Antenna towers
Site building
Container | BSC, MSC, HLR, SGSN,
GGSN, media gateway
(MGW) | +| 3G mobile network | 3G base stations | Same as 2G above | RNC, MSC, HLR, SGSN,
GGSN, MGW | +| Fourth generation
telecom networks (4G)
mobile network | 4G base stations | Same as 2G above | | +| Fibre / City LAN
network | | Fibre network | | +| CATV broadband
network | | Coax cable network | Fibre nodes | + +## **Appendix V** + +### **Energy mix** + +(This appendix does not form an integral part of this Recommendation.) + +One of the main environmental impacts of ICTs affecting climate change is GHG emissions from electric power consumption. These GHG emissions depend on sources of electric power generations such as coal, oil, natural gas and nuclear. Conditions of electric power generation are quite different among countries. Also, even in the same country or region, annual GHG emission intensity differs; this is due mainly to the amount of nuclear power generation and renewable energy installed. Therefore, environmental impact assessment of ICTs needs to be carried out carefully when the assessment target includes regions or terms in which GHG emission intensity differs. The impacts should be assessed in energy units for the sake of performing objective and fair assessments. However, this requirement to assess ICT impacts in energy units is not intended to permit a comparative assertion for commercial competition. + +## Appendix VI + +### Examples of Allocation Procedures + +(This appendix does not form an integral part of this Recommendation.) + +NOTE – A factor: factor allocating burdens and credits from recycling and primary material production between the life cycle supplying and using recycled material. + +### VI.1 Allocation examples for Recycling of Materials + +The examples in Figures VI.1 and VI.2 are applying different allocation methods for one scenario. The example (Table VI.1) is referring to climate change but the same principles apply to all impact categories. + +Table VI.1 – Allocation scenario (example) + +| Parameter | Value | +|----------------------------|-------------------------------------------------------------------------------------------------| +| Total raw material input | 1 kg | +| R1 | 40%, Share of recycled materials used in the raw materials acquisition stage | +| R2 | 90%, Share of material recycled in the EoLT stage | +| $E_v$ | 80 kg CO 2 e/kg, based on life cycle inventory for primary material production | +| $E_{\text{recycled}}$ | 10 kg CO 2 e/kg, life cycle inventory for recycling process of the recycled material | +| $E_{\text{recycled, EoL}}$ | 0.1 kg CO 2 e/kg, life cycle inventory for recycling process at EoL | +| A | Allocation factor of burden and credits between supplier and user of recycled materials | +| $Q_{\text{sin}}$ | 1, Quality of ingoing secondary material | +| $Q_{\text{sout}}$ | 1, Quality of outgoing secondary material | +| $Q_p$ | 1, Quality of outgoing primary material | + +It is also assumed that the **total raw material input** includes both goods raw material acquisition and generic raw material acquisition and further production waste is included in the EoLT waste. + +Equation VI.1 gives the LCIs for equipment raw material acquisition (A) + raw material acquisition (G5) and equation VI.2 the LCI for raw material recycling (G7). + +$$\begin{aligned} &\text{LCI for equipment raw material acquisition (A) + raw material acquisition (G5)} = \\ &(1-R1) \times E_v + R1 \times ((A \times E_{\text{recycled}} + (1-A) \times E_v \times Q_{\text{sin}}/Q_p)) \end{aligned} \quad (\text{VI.1})$$ + +$$\text{LCI for raw material recycling (G7)} = (1-A) \times R2 \times (E_{\text{recycled, EoL}} - E_v \times Q_{\text{sout}}/Q_p) \quad (\text{VI.2})$$ + +#### VI.1.1 Example of the 100/0 and 0/100 methods + +An example of *raw material acquisition* and *raw material recycling* with the 100/0 and the 0/100 methods is given below in Figure VI.1. + +Some of the 100/0 values are calculated as: + +$$52 = (1-40\%) \times 80 + 40\% \times ((1 \times 10 + (1-1) \times 80 \times 1/1))$$ + +$$0 = (1-1) \times 90\% \times (1-80 \times 1/1)$$ + +Some of the 0/100 values are calculated as: + +$$80 = (1-40\%) \times 80 + 40\% \times ((0 \times 10 + (1-0) \times 80 \times 1/1))$$ + +$$-71.1 = (1-0) \times 90\% \times (1-80 \times 1/1)$$ + +![Bar chart titled '100/0 and 0/100 methods, kg CO2e' comparing the 100/0 method (blue bars) and the 0/100 method (orange bars) across five categories: Equipment raw material acquisition (A) and raw material acquisition (G5), Production (B), Use (C), EoLT (D), and Raw material recycling (G7). The TOTAL row shows the sum of all categories. The y-axis ranges from -100 to 250 kg CO2e.](a75c2cd397490e8a9b0fa811a6a1b2c3_img.jpg) + +| Category | 100/0 (kg CO 2 e) | 0/100 (kg CO 2 e) | +|--------------------------------------------------------------------------|------------------------------|------------------------------| +| Equipment raw material acquisition (A) and raw material acquisition (G5) | 52 | 80 | +| Production (B) | 35 | 35 | +| Use (C) | 100 | 100 | +| EoLT (D) | 5 | 5 | +| Raw material recycling (G7) | 0 | -71.1 | +| TOTAL | 192 | 148.9 | + +L.1410(24) + +Bar chart titled '100/0 and 0/100 methods, kg CO2e' comparing the 100/0 method (blue bars) and the 0/100 method (orange bars) across five categories: Equipment raw material acquisition (A) and raw material acquisition (G5), Production (B), Use (C), EoLT (D), and Raw material recycling (G7). The TOTAL row shows the sum of all categories. The y-axis ranges from -100 to 250 kg CO2e. + +**Figure VI.1 – Example showing the 100/0 method and the 0/100 method** + +#### VI.1.2 Example of the 50/50, 20/80 and 80/20 methods + +Examples of *raw material acquisition* and *raw material recycling* with the 50/50, 20/80 and 80/20 methods are given below in Figure VI.2. The methods differently show the importance of the raw material acquisition and the raw material recycling processes. + +Some of the 50/50 values are calculated as: + +$$66 = (1-40\%) \times 80 + 40\% \times ((0.5 \times 10 + (1-0.5) \times 80 \times 1/1))$$ + +$$-35.55 = (1-0.5) \times 90\% \times (1-80 \times 1/1)$$ + +Some of the 20/80 values are calculated as: + +$$74.4 = (1-40\%) \times 80 + 40\% \times ((0.2 \times 10 + (1-0.2) \times 80 \times 1/1))$$ + +$$-56.88 = (1-0.2) \times 90\% \times (1-80 \times 1/1)$$ + +Some of the 80/20 values are calculated as: + +$$57.6 = (1-40\%) \times 80 + 40\% \times ((0.8 \times 10 + (1-0.8) \times 80 \times 1/1))$$ + +$$-14.22 = (1-0.8) \times 90\% \times (1-80 \times 1/1)$$ + +![Bar chart titled '50/50, 20/80 and 80/20 allocation methods, kg CO2e'. The chart compares three allocation methods (50/50, 20/80, and 80/20) across five categories: Equipment raw material acquisition (A) and raw material acquisition (G5), Production (B), Use (C), EoLT (D), and Raw material recycling (G7). The TOTAL category shows the sum of all values. The y-axis ranges from -100 to 200 kg CO2e. The legend indicates 50/50 is blue, 20/80 is orange, and 80/20 is grey.](aca79615c15f2486a6712fb2f8222035_img.jpg) + +| Category | 50/50 (kg CO 2 e) | 20/80 (kg CO 2 e) | 80/20 (kg CO 2 e) | +|--------------------------------------------------------------------------|------------------------------|------------------------------|------------------------------| +| Equipment raw material acquisition (A) and raw material acquisition (G5) | 66 | 74.4 | 57.6 | +| Production (B) | 35 | 35 | 35 | +| Use (C) | 100 | 100 | 100 | +| EoLT (D) | 5 | 5 | 5 | +| Raw material recycling (G7) | -35.55 | -56.88 | -14.22 | +| TOTAL | 170.45 | 157.52 | 183.38 | + +Bar chart titled '50/50, 20/80 and 80/20 allocation methods, kg CO2e'. The chart compares three allocation methods (50/50, 20/80, and 80/20) across five categories: Equipment raw material acquisition (A) and raw material acquisition (G5), Production (B), Use (C), EoLT (D), and Raw material recycling (G7). The TOTAL category shows the sum of all values. The y-axis ranges from -100 to 200 kg CO2e. The legend indicates 50/50 is blue, 20/80 is orange, and 80/20 is grey. + +**Figure VI.2 – Example of the 50/50, 20/80 and 80/20 methods** + +The 50/50 method focuses equally on recycling rate and recycled content and should be used when the allocation factor for the material at hand is unknown. + +The 20/80 method focuses mostly on recycling rate and should be used when the supply of recyclable materials is low. + +The 80/20 method focuses mostly on recycled content and should be used when the supply of recyclable materials is high. + +Table VI.2 gives an example of the 50/50 method with USGS average numbers applied to recycled contents (R1) and 90 % raw material recycling (R2) assumed for the studied product. + +NOTE – The applicability of USGS average numbers varies case by case i.e., depending on the conditions of the equipment the USGS average numbers may be more or less representative to the actual conditions. However, for raw materials the exact recycling conditions are usually hard to track for a specific ICT good, network or service. + +**Table VI.2 – Example of the 50/50 method for 1 kg material** + +| | Raw material acquisition, $E_v$ [CO 2 e/kg] | Raw material recycling process of recycled material (reprocessing / remelting), $E_{recycled}$ [CO 2 e/kg] | Recycling process at EoL (sorting, disassembly), $E_{recycled, EoL}$ [CO 2 e/kg] | USGS average recycling [%], R1 (see Note) | Results with 90% recovery efficiency (R2) in raw material recycling and 50/50 method [CO 2 e] | +|-----------|--------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------|-------------------------------------------|----------------------------------------------------------------------------------------------------------| +| Steel | 2.5 | 0.5 to 1 | 0.05 to 0.1 | 50 | 0.89 to 1.05 | +| Copper | 7 | 1.5 to 2 | 0.15 to 0.2 | 30 | 3.09 to 3.19 | +| Aluminium | 12 | 1.5 | 0.15 | 35 | 4.83 | + +NOTE – For most up to date USGS average numbers refer to USGS. + +## Appendix VII + +### Example of data quality indicators + +(This appendix does not form an integral part of this Recommendation.) + +Table VII.1 shows an example of data quality indicators. There are several ways to mathematically evaluate the data quality of an entire LCA and estimate which data quality indicators are most important for the overall data quality. However, in many cases only a qualitative approach is possible due to lack of quantitative data. This Recommendation lists which data quality indicators should be taken into account for such calculations. There may be more applicable data quality indicators than listed in Table VII.1. + +**Table VII.1 – Matrix for data quality assessment** + +| Data quality indicator | Applicable clause | Comment | | | | | +|------------------------------------------------------------|-------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------|----------------------------------------------------------------|---------------------------------------------------------------|----------------------------------------------------------------| +| | | < 3 years | < 6 years | < 10 years | < 15 years | Age unknown | +| Methodological appropriateness and consistency | Entire specification/document | Indication of how well the applied LCI methods and methodological choices align with the goal and scope of the data, as well as how consistently the methods have been applied across all data. | | | | | +| Completeness | 7.2.4 | Indication of the % of applicable LCI flows in Table G.1 which are included in the LCI. Also, degree of coverage of an LCIA indicator in Table L.10. | | | | | +| Uncertainty | 9.2 | Indication of the variability of the data elements used in the LCA. | | | | | +| Acquisition method | 7.2.5 | Indication of how the data used have been obtained. The range is roughly from directly measured to nonqualified estimations. | | | | | +| Supplier independence | 7.2.5 | Indication of the verifiability of the data. The range is roughly from verified data from independent source to unverified information. | | | | | +| Data representativeness | 7.2.5 | Indication of the number of facilities and time range from which the data have been collected. Range is roughly from "representative data from a sufficient number of facilities over and adequate time period" to "information with unknown representativeness from a small number of facilities from a shorter time periods". | | | | | +| Data age/timeliness | 7.2.5 | < 3 years | < 6 years | < 10 years | < 15 years | Age unknown | +| Geographical correlation | 7.2.5 | Data from the exact area | Average data from a larger area | Data from an area with similar production conditions | Data from an area with slightly similar production conditions | Unknown area | +| Technological correlation | 7.2.5 | Data from process studied of the exact company | Data from process studied of company with similar technology | Data from process studied of company with different technology | Data from process related to company with similar technology | Data from process related to company with different technology | +| Rule of inclusion/exclusion (Elements/Flows/ Unit process) | 7.2.4 | Indication of how homogeneously and transparently the cut-off criteria have been applied. | | | | | + +## Appendix VIII + +### Uncertainties of life cycle assessments for ICT goods, networks and services + +(This appendix does not form an integral part of this Recommendation.) + +Uncertainty is an important aspect of a life cycle assessment of ICT goods, networks and services. + +The uncertainty of an LCA can be divided into three categories: + +- parameter uncertainty +- scenario uncertainty +- model uncertainty. + +**Parameter uncertainty:** This is related to uncertainties in input data and provides a measure of how close the data and calculated emissions are to the real data and emissions. This includes uncertainties in the inventory analysis and uncertainties when translating inventory flows into environmental impact potential. The influence of parameter uncertainty on the final result can be assessed analytically or by simulations. One example of parameter uncertainty is the uncertainty associated with the conversion from the emissions of carbon dioxide (CO2) and other GHGs into carbon dioxide equivalents (CO2e). + +**Scenario uncertainty:** This represents a variation of results depending on methodological choices, e.g., LCI modelling principles, allocation procedures and cut-off decisions. The scenario uncertainty can be quantified through sensitivity analysis. Sources of scenario uncertainties include e.g., the allocation method for data for production facilities, overhead activities (see Note 1) and vehicle use to the product system studied (see Note 2) and also use of old data to represent current activities. + +NOTE 1 – Often based on economic data. + +NOTE 2 – Emission data for a site is typically measured at the site level and not for individual processes and products. + +**Model uncertainty:** This arises from insufficient knowledge of the studied system, leading to omission of data or incorrect assumptions. Model uncertainties are difficult to quantify. Aviation emissions such as nitrogen oxides (NOX) and soot, as well as effects like land use are examples of emissions/effects usually left out because of a lack of knowledge. One source of model uncertainty that is widely discussed is the possible inclusion of emissions from infrastructure and the supply chain for travel and transportation activities (see Note 3). + +NOTE 3 – Decisions regarding which activities to include in the life cycle is part of the system boundary setting of a study. + +Some important uncertainty sources for different life cycle stages. + +The table below summarizes some important uncertainty sources associated with different life cycle stages. Some of them are described further below Table VIII.1. + +**Table VIII.1 – Important uncertainty sources of the different life cycle stages** + +| Life cycle stage | Activities included | Important uncertainty sources | +|--------------------------|----------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Raw material acquisition | Raw material extraction
Raw material processing | Long supply chain without direct commercial relationship to ICT industry. Variations in geographical location. World market variations beyond the control of ICT. | +| Production | ICT goods production
Support goods production | Large supplier base which changes continuously over product system lifetime based on price, availability, etc. Allocation of facility data between product systems and processes. | +| Use | ICT goods use
Support goods use
Support activities | Life time, geographical location, traffic scenario model. Large variations between operators regarding site and network design and energy consumption. Electricity production model and power supply variations. | +| End-of-life treatment | ICT-specific EoLT
Other EoLT | Future processes principally unknown. Significant variations between suppliers and regions. Allocation of facility data between product systems and processes. | + +Within the raw material acquisition and production stages it is very challenging to collect all product system specific data for the whole upstream supply chain (see Note 1). Raw material acquisition depends on long supply chains related to world market variations beyond the control of the ICT sector and the supplier base changes continuously over the different product systems' lifetime based on price, availability, etc. Emissions are therefore generally estimated based on assumptions and generic product models (see Note 2). Such a process generates both parameter uncertainties within the data collected and scenario uncertainties regarding the selection of data to collect. In addition, model uncertainties are incorporated if the generic model is associated with insufficient knowledge. + +NOTE 1 – A magnitude of thousand facilities could be associated with the supply chain of a major ICT company. + +NOTE 2 – An LCA study can involve hundred models using thousands of parameters. + +For the use stage estimated, product system lifetimes / operating lifetimes for the goods featuring in the studied product system can generate essential scenario uncertainties. A two-fold increase of the studied product system's lifetime will result in a two-fold increase of emissions from studied product system operation if lifetime results are presented. Model uncertainties related to product system operation also include assumptions regarding the electricity production and amount of traffic. + +End-of-life treatment (EoLT) and transport typically include model uncertainties related to a lack of comprehensive sub-supplier data. For EoLT, there are significant variations between suppliers, especially between regions, and future treatment processes are principally unknown. + +## Appendix IX + +### Opportunities and limitations in the use of LCAs for ICT goods, networks and services + +(This appendix does not form an integral part of this Recommendation.) + +A life cycle assessment (LCA) is a systematic methodology which gives an understanding of the relative importance of the different life cycle stages/activities. LCAs assist companies in determining where to put their efforts to improve life cycle environmental performance and also to monitor how this performance changes over time. However, it is important to keep in mind that the results of an LCA are always model-based representations of real environmental impact, and the absolute impact of a certain product, network, service or organization is beyond reach. This applies to all product systems but is especially true for the complex product systems of the ICT sector. + +An LCA addresses potential environmental impact; however, it does not predict absolute or precise environmental impact. This is due to the relative expression of potential impacts to a reference unit, the integration of environmental data over space and time, the inherent uncertainty in modelling environmental impact, and the fact that some possible environmental impacts are clearly future impacts ([ISO 14040], clause 4.3). + +In practice, it is virtually impossible to collect enough data for an assessment to give the absolute performance of a product system. Even then, the results would still have model and scenario uncertainty. + +Consequently, any LCA result is only valid under the assumptions of the study and is still associated with substantial uncertainty, which needs to be considered so the outcome of the assessment is interpreted in a correct way. + +Example 1: + +An environmental performance parameter is assessed in two different studies for two goods, A and B. The calculated difference in performance between A and B is 25%. The estimated uncertainty of the parameter is 50%. In this case it is not possible to judge if A or B is a better good with respect to the assessed parameter, although the result value indicates a clear difference. + +Example 2: + +An environmental performance parameter is assessed for a scenario with an ICT service applied and a scenario without the service applied (business-as-usual scenario). The estimated uncertainty of the parameter is 50% in this case as well, but the calculated improvement in performance when applying the ICT service is a factor of ten. In this case, it can be concluded that the scenario with the ICT service clearly has the best performance even though the uncertainty of the performance parameter impacts the absolute value of the performance. + +The above examples illustrate that both uncertainty analysis and sensitivity analysis are important tools to understand the results of a study and what conclusions can be made. + +#### Appropriate use of LCAs + +Due to these conditions, LCAs should primarily be used for the following purposes: + +- identification of opportunities to improve the environmental performance of goods, networks, services and organizations; +- information to decision-makers in industry, government or non-government organizations about typical environmental performance of a product system/organization to assist their policy choices; +- selection of relevant indicators of environmental performance for monitoring; + +- understanding of the potential impact of new services and solutions; +- understanding of improvements between generations. + +Contrarily, an LCA is less suitable for: + +- quantitative benchmarking between studies; +- aggregation1 of results between studies; +- product system performance legislation (measurable parameters more appropriate); and +- labelling of ICT goods, networks and services. + +--- + +1 With sufficient accuracy. + +## Appendix X + +### Examples for calculating second order effects + +(This appendix does not form an integral part of this Recommendation.) + +Below are examples for calculating second-order effects using fictitious values for the difference between the reference product system and the ICT goods, networks and services product system. Conversion factors used were from the LCI database. + +Equation X.1 shows a formula for calculating the second order effects, $EI_{\text{difference}}$ : + +$$EI_{\text{difference},i} = EI_{\text{reference},i} - EI_{\text{ICT goods, networks, and services},i} \quad (\text{X.1})$$ + +Below, this formula is applied to various second order effects. + +### X.1 Consumption of goods (paper, CDs, DVDs, etc.) + +If the consumed good is paper: + +$$EI_{\text{difference},i=1} = (\text{amount of paper consumed}_{\text{reference}} - \text{amount of paper consumed}_{\text{ICT goods, networks, and services}}) \text{ (kg paper/fu)} \times \text{conversion factor (EI/kg paper)}$$ + +where, + +fu = functional unit. + +Conversion factor = factor converting inventory data into impact data, e.g., greenhouse gas emission factor in the case of global warming impact. + +Example: + +Net amount of paper consumed (difference between the reference and the ICT service) = 10 kg paper/fu + +Conversion factor for paper = 1.3 kg CO2e/kg paper + +$$EI_{\text{difference},i=1} = 10 \text{ kg paper/fu} \times 1.3 \text{ kg CO}_2\text{e/kg} = 13 \text{ kg CO}_2\text{e/fu}$$ + +### X.2 Power consumption/energy consumption (electricity, gasoline, kerosene, light oil, heavy oil, town gas, etc.) + +If the consumed power is electricity: + +$$EI_{\text{difference},i=2} = (\text{amount of electricity consumed}_{\text{reference}} - \text{amount of electricity consumed}_{\text{ICT goods, networks, and services}}) \text{ (kWh/fu)} \times \text{conversion factor (EI/kWh)}$$ + +Example: + +Net amount of power consumed (difference between the reference and the ICT service) = -300 kWh/fu + +Conversion factor for electricity = 0.49 kg CO2e/kWh + +$$EI_{\text{difference},i=2} = -300 \text{ kWh/fu} \times 0.49 \text{ kg CO}_2\text{e/kWh} = -147 \text{ kg CO}_2\text{e/fu}$$ + +### X.3 Movement of people (car, bus, railroad, aircraft, etc.) + +If the movement of people is done by car: + +$$EI_{\text{difference},i=3} = (\text{number of passengers} \times \text{distance travelled}_{\text{reference}} - \text{number of passengers} \times \text{distance travelled}_{\text{ICT goods, networks, and services}}) \text{ (passenger-km/fu)} \times \text{conversion factor (EI/passenger-km)}$$ + +Example: + +Net passenger-km travelled (difference between the reference and the ICT service) + = 2 000 passenger-km/fu + +Conversion factor for a passenger car = 0.10 kg CO2e/passenger-km + +$$EI_{\text{difference},i=3} = 2\ 000\ \text{passenger-km/fu} \times 0.10\ \text{kg CO}_2\text{e/passenger-km} = 200\ \text{kg CO}_2\text{e/fu}$$ + +### **X.4 Movement and storage of goods (mail, truck, railroad cargo, air cargo, cargo ship, etc.)** + +If the movement of goods is done using a 10-tonne truck: + +$$EI_{\text{difference},i=4} = (\text{tonnes of goods transported} \times \text{distance transported}_{\text{reference}} - \text{tonnes of goods transported} \times \text{distance transported}_{\text{ICT goods, networks, and services}}) (\text{tonne-km/fu}) \times \text{conversion factor (EI/tonne-km)}$$ + +Example: + +Net tonne-km transported (difference between the reference and the ICT service) = 1 000 tonne-km/fu + +Conversion factor for a 10-tonne truck = 0.1 kg CO2e/tonne-km + +$$EI_{\text{difference},i=4} = 1\ 000\ \text{tonne-km/fu} \times 0.10\ \text{kg CO}_2\text{e/tonne-km} = 100\ \text{kg CO}_2\text{e/fu}$$ + +If the storage of goods affects the consumption of electricity + +$$EI_{\text{difference},i=6} = (\text{amount of electricity consumed}_{\text{reference}} - \text{amount of electricity consumed}_{\text{ICT goods, networks, and services}})(\text{kWh/fu}) \times \text{conversion factor (EI/kWh)}$$ + +Example: + +Net amount of power consumed (difference between the reference and the ICT service) = 100 kWh/fu + +Conversion factor for electricity = 0.49 kg CO2e/kWh + +$$EI_{\text{difference},i=6} = 100\ \text{kWh/fu} \times 0.49\ \text{kg CO}_2\text{e/kWh} = 49\ \text{kg CO}_2\text{e/fu}$$ + +### **X.5 Improved work efficiency (electricity, office area, etc.)** + +If improved efficiency occurs in the area of electricity: + +$$EI_{\text{difference},i=5} = (\text{amount of electricity consumed}_{\text{reference}} - \text{amount of electricity consumed}_{\text{ICT goods, networks, and services}})(\text{kWh/fu}) \times \text{conversion factor (EI/kWh)}$$ + +Example: + +Net amount of power consumed (difference between the reference and the ICT service) = 200 kWh/fu + +Conversion factor for electricity = 0.49 kg CO2e/kWh + +$$EI_{\text{difference},i=5} = 200\ \text{kWh/fu} \times 0.49\ \text{kg CO}_2\text{e/kWh} = 98\ \text{kg CO}_2\text{e/fu}$$ + +If the improved efficiency affects the area of the office space: + +$$EI_{\text{difference},i=7} = (\text{area of office space}_{\text{reference}} - \text{area of office space}_{\text{ICT goods, networks, and services}})(\text{m}^2/\text{fu}) \times \text{conversion factor (EI/m}^2\text{)}$$ + +Example: + +Net area of office space reduced (difference between the reference and the ICT service) = 100 m2/fu + +Conversion factor for office space area = 2.0 kg CO2e/m2 + +$$EI_{\text{difference},i=7} = 100\ \text{m}^2/\text{fu} \times 2.0\ \text{kg CO}_2\text{e/m}^2 = 200\ \text{kg CO}_2\text{e/fu}$$ + +### X.6 Waste (wastepaper, garbage, plastic, industrial waste, etc.) + +If the concerned waste is waste plastic for incineration: + +$$EI_{\text{difference},i=8} = (\text{amount of waste plastic}_{\text{reference}} - \text{amount of waste plastic}_{\text{ICT goods, networks, and services}}) \text{ (kg waste plastic/fu)} \times \text{conversion factor (EI/kg waste plastic)}$$ + +Example: + +Net amount of waste plastic (difference between the reference and the ICT service) = 10 kg waste plastic/fu + +Conversion factor for waste plastic = 2.8 kg CO2e/kg waste plastic + +$$EI_{\text{difference},i=8} = 10 \text{ kg waste plastic /fu} \times 2.8 \text{ kg CO}_2\text{e/kg} = 28 \text{ kg CO}_2\text{e/fu}$$ + +Summing up the $EI_{\text{difference}}$ for the all the comparison categories gives the second-order effects of the ICT goods, networks and services product system compared with the reference product system. Table X.1 lists second order effects for each comparison category. + +**Table X.1 – Second order effects for each comparison category** + +| | Comparison category | Second order effect (kg CO2e) | +|---|-----------------------------------------------------------------------|-------------------------------------------------| +| 1 | Consumption of goods (paper) | 13 | +| 2 | Energy consumption (electricity) | −147 | +| 3 | Movement of people (passenger car) | 200 | +| 4 | Movement of goods (10-tonne truck) and storage of goods (electricity) | 149 | +| 5 | Improved work efficiency (electricity and work space) | 298 | +| 6 | Waste (waste plastic for incineration) | 28 | +| | Total | 541 | + +Thus, the second-order effects of the ICT goods, networks and services product system are 541 kg CO2e/fu. The EI difference can also be calculated and presented with respect to life cycle stages and components of the systems of ICT goods, networks and services as shown in Figures 25 and 26 in clause 14. + +## Appendix XI + +### GWP values 100-year time frame + +(This appendix does not form an integral part of this Recommendation.) + +The most up-to-date GWP as of May 2014 are shown Table XI.1 below. + +**Table XI.1 – GWP 100-year values for some GHGs** + +| GHG | GWP 100 years values from IPCC 5th AR
page 714) (IPCC 4th AR 2007 page 212) | +|-----------------------------|----------------------------------------------------------------------------------------| +| Carbon dioxide | 1 (1) | +| Methane | 32 (25) | +| Nitrous oxide | 298 (298) | +| Hydrofluorocarbons HFC-134a | 1550 (1430) | +| Perfluorocarbons | 7390-12200 (7390-12200) | +| Sulphur hexafluoride | 22,800 (22,800) | +| Nitrogen trifluoride | 17,200 (n/a) | + +## **Appendix XII** + +### **Summary of requirements** + +(This appendix does not form an integral part of this Recommendation.) + +This appendix (Table XII.1) summarizes all requirements present in the main body of this Recommendation. In addition, this Recommendation contains numerous recommendations which also need consideration. + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|-------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|----------------------|------------------------------------------------| +| Introduction | Deviation(s) from the requirements shall be clearly motivated and reported. | | | | +| 6.2 | Full compliance with this Recommendation can be claimed if all mandatory requirements are fulfilled. | | | | +| 6.3 | A third-party review is also needed if the comparison result is to be externally communicated. | | | | +| 6.3 | In case of comparative assessment between ICT goods LCAs, the operating lifetime shall be set to equal. | | | | +| 7.1 | The requirements of this Recommendation shall apply as well as those of [ISO 14040] and [ISO 14044]. | | | | +| 7.1.1 | The following four high-level life cycle stages (raw material acquisition (RMA), P, U, EOLT) shall apply to ICT goods, networks and services and shall be assessed as applicable in LCAs based on this Recommendation in accordance with the goal and scope. | | | | +| 7.1.1 | Table 2 in clause 7.2.3.1 defines the detailed life cycle stages which further define the system boundary, and which are to be considered when assessing the life cycle impact of ICT goods, networks and services. In particular, it is important to cover all processes whose relevance is marked as mandatory in that table. | | | | +| 7.1.1 | The data collected shall be structured in such a way that the greenhouse gas (GHG) emissions and energy consumption/environmental impact arising from the transportation processes could be reported transparently, as far as possible. | | | | +| 7.1.1 | Impacts from transport and energy supplies shall be included in all life cycle stages. | | | | +| 7.1.1 | At the time of publication, to collect appropriate data related to raw materials transportation and to separate data related to raw material acquisition stage and production stage is considered challenging due to LCA tool limitations, lack of data, limitations in data granularity and the nature of ICT supply chains.
Deviation(s) from this requirement shall be clearly motivated and reported. | | | | +| 7.1.1 | For instance, the transportation of goods between production and use stages shall be taken into account. | | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|-------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|----------------------|------------------------------------------------| +| 7.1.3 | The ICT goods, networks and services product system to be assessed shall be clearly described, as well as relevant functions and characteristics. | | | | +| 7.1.3.1 | For the ICT good under study, applicable types of parts, as well as the amounts of these, shall be defined. | | | | +| 7.1.3.2 | In the goal and scope phase, it shall be outlined which network building blocks are covered. | | | | +| 7.1.3.2 | For the ICT network under study, applicable types of nodes and infrastructure, as well as amounts of these, shall be defined. | | | | +| 7.1.3.3 | For the ICT service under study, applicable types of ICT network elements and infrastructure, as well as the amounts of these, shall be defined. | | | | +| 7.1.4.1 | Software shall be considered, as well as hardware. | | | | +| 7.1.4.1 | For specific software applications, such as music distribution applications, the software is to be seen as an ICT service and shall be assessed according to the requirements outlined for services. | | | | +| 7.1.4.1 | In these cases, the hardware needed to operate the software shall be considered as well. | | | | +| 7.1.4.1 | For users of generic operating systems embedded in products, the life cycle impact of usage of this software may be considered as negligible. However, for the developer of this software the impact of the usage of this software shall be taken into account. | | | | +| 7.1.5 | Operating lifetime is critical for the interpretation of the results of LCAs and shall therefore always be reported when presenting LCA results. | | | | +| 7.1.5 | Operating lifetime estimates and assumptions shall also be clearly described in the reporting. | | | | +| 7.2.1 | During the LCA scoping phase, the building blocks of the ICT goods, networks or services shall be identified. | | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|-------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|----------------------|------------------------------------------------| +| 7.2.2.1 | The functional unit shall be chosen in accordance with the goal and scope of the LCA. | | | | +| 7.2.2.1 | The functional unit requires inclusion of the relevant quantifiable properties and the technical/functional performance of the system. This means that the operating lifetime of all included ICT goods shall be specified. | | | | +| 7.2.2.1 | The number of users/subscribers supported by the network and the traffic profile shall be included, where applicable. | | | | +| 7.2.2.1 | The functional unit shall be clearly defined and measurable. | | | | +| 7.2.2.1 | The reference flow shall reflect the chosen functional unit. | | | | +| 7.2.2.2 | The functional unit shall be chosen in the context of the goal and scope of the LCA and shall be further clarified by system boundary and cut-off rules. | | | | +| 7.2.2.2 | To comply with this Recommendation, the following functional unit shall be applied where applicable:
  • • Annual ICT goods use (per one year of ICT good use), or
  • • Total ICT good use per lifetime of ICT good.
| | | | +| 7.2.2.2 | For relevant LCA results, realistic use scenarios shall be captured. | | | | +| 7.2.2.3 | ICT networks can be seen as a system composed of different types of ICT goods. For the purposes of this Recommendation, the following functional unit shall be applied, where applicable, for ICT networks used for at least one year:
  • • Annual network use.
| | | | +| 7.2.2.3 | For relevant LCA results, realistic use scenarios shall be captured. | | | | +| 7.2.2.4 | For the purposes of this Recommendation, the following functional unit shall be applied where applicable:
  • • Annual service use.
| | | | +| 7.2.2.4 | For relevant LCA results, realistic use scenarios shall be captured. | | | | +| 7.2.2.4 | Corresponding realistic use scenarios shall be defined. | | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in
ITU-T L.1410 | Requirement | Fulfilled | Not
fulfilled | Explanation/Motivation
if not compliant | +|-----------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|--------------------------|----------------------------------------------------| +| 7.2.2.4 | The annual service use shall be defined with respect to the usage scenario to make it possible to define the reference flow. | | | | +| 7.2.3.1 | The selection of the system boundary shall be consistent with the goal of the study. | | | | +| 7.2.3.1 | Consequently, the system boundaries here define the life cycle stages and the unit processes that shall be taken into account in an LCA of an ICT product system. | | | | +| 7.2.3.1 | Table 2 includes further details of the life cycle stages to be included in LCAs of ICT goods, networks and services. The different life cycle stages are further described in clauses 7.2.3.3.2 to 7.2.3.3.5. Mandatory in Table 2 means that the life cycle stage shall be included. | | | | +| 7.2.3.1 | Mandatory life cycle stages or unit processes shall not be cut off before considered for inclusion by using alternative data. | | | | +| 7.2.3.1 | In Table 2 'Mandatory' means that the life cycle stage, if applicable to the studied product system, shall always be taken into account in an LCA for ICT. | | | | +| 7.2.3.3.1 | In order to set the system boundary of ICT goods, the life cycle stages listed in clause 7.1.1 shall be detailed. | | | | +| 7.2.3.3.1 | As stated in clause 7.1.4, the environmental impact from both hardware and software shall be considered, if applicable. | | | | +| 7.2.3.3.1 | For the ICT good under study, applicable types of parts, as well as the amounts of these, shall be defined. | | | | +| 7.2.3.3.2 | Annex H (Table H.1) provides a mandatory set of raw materials (both ICT-specific and generic) which shall be included in the LCA of ICT goods. | | | | +| 7.2.3.3.3 | Annex E lists a mandatory set of parts to be included where applicable to the studied ICT product system, when performing an LCA of ICT goods, as well as mandatory part unit processes which shall be included for each part. | | | | +| 7.2.3.3.3 | As an example, if batteries are part of the studied ICT goods product system, they shall be included within the system boundary, and for every battery, the battery cell manufacturing and battery module manufacturing shall be included. | | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------|---------------|-----------------------------------------| +| 7.2.3.3.3 | The Assembly (B1.2) shall include as minimum PCBA module assembly, final assembly, warehousing, and packaging. | | | | +| 7.2.3.3.3 | In case support goods are part of the studied product system, support goods Production (B2) is mandatory. | | | | +| 7.2.3.3.3 | Support goods (B2.1) which shall be included if applicable to the studied product system include at least air conditioners, cables, and power supply systems. | | | | +| 7.2.3.3.3 | As stated in Table 2, construction of ICT-specific site (B3) is mandatory if the ICT-specific site is included in the studied product system. | | | | +| 7.2.3.3.3 | Site building blocks to be included in B3.1, if they are applicable to the studied product system, are antenna towers, fences and shelters. | | | | +| 7.2.3.3.4 | Raw material acquisition and production for the additional PCBAs and other goods used during the operating lifetime of the ICT goods are mandatory. | | | | +| 7.2.3.3.5 | As shown in Figure 11, preparation of ICT goods for extended operating lifetime (D1), ICT-specific EoLT (D2) and other EoLT (D3) are within the mandatory system boundary for EoLT. | | | | +| 7.2.3.3.5 | Annex F lists a mandatory set of EoLT processes to be included, where applicable, when performing an LCA of ICT goods which includes the EoLT stage. | | | | +| 7.2.3.3.5 | It is thus recognized that compliance to all requirements in Annex F may not be possible at the time this Recommendation is published. Deviation(s) from the requirements shall be clearly motivated and reported. | | | | +| 7.2.3.4 | The network shall be defined in terms of ICT goods, Support goods and ICT infrastructure (e.g., cables duct). | | | | +| 7.2.3.4 | For each included product types, the number of units shall be defined, as well as their corresponding lifetimes. | | | | +| 7.2.3.4 | For the assessment of networks, operator activities shall always be included. | | | | +| 7.2.3.5.1 | In addition to the use of ICT goods and networks, an ICT service may also have additional impacts associated with application software development, use of | | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|-------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|----------------------|------------------------------------------------| +| | consumables, infrastructure for sales and logistics, associated travel and transport (in addition to those already included for the ICT goods and networks) which shall also be included as appropriate. | | | | +| 7.2.3.5.1 | The impact of the data centres where the service is operated shall be assessed. | | | | +| 7.2.3.5.1 | The data centre shall be studied and assessed in the same way as other ICT goods and support goods. | | | | +| 7.2.3.5.1 | The system boundary of the ICT services provided by the ICT network shall be established based on either the actual use scenario of the ICT services, if available, or on an estimated use scenario. | | | | +| 7.2.3.5.2 | Energy consumption, material inputs and environmental releases shall be assessed in accordance with the system boundary. | | | | +| 7.2.4 | Cut-offs shall be avoided as far as possible. | | | | +| 7.2.4 | [ISO 14044], clause 4.2.3.3 recommendations shall be followed as closely as possible. | | | | +| 7.2.4 | All cut-off criteria stated by [ISO 14040] and [ISO 14044] are to be considered before cut-off of a certain process, and the process shall be included if significant to at least one criterion. | | | | +| 7.2.4 | The intention of this Recommendation is to include all mandatory activities of Table 2. If these activities are not included such cut-offs shall be clearly motivated. | | | | +| 7.2.4 | Any cut-off made shall be clearly described and documented. | | | | +| 7.2.5.1 | A qualitative description of the data quality and any efforts taken to improve it shall be disclosed while considering the following data quality indicators:
  • • Methodological appropriateness and consistency
  • • Completeness (total LCA level)
  • • Uncertainty
  • • Data representativeness
  • • Data age (timeliness)
| | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|-------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|----------------------|------------------------------------------------| +| |
  • Acquisition method
  • Supplier independence
  • Geographical correlation
  • Technological correlation
  • Cut-off rules (rules of inclusion/exclusion)
| | | | +| 7.2.5.1 | In selecting emission factors for use in calculating GHG emissions under this methodology, the following guidance shall be followed:
Emission factors used should be the most up to date from publicly available sources. | | | | +| 7.2.5.1 | Where emission factors are sourced from non-public sources, or are not the most up-to-date ones, a justification for their use shall be provided. | | | | +| 7.2.5.1 | The specific global warming potential (GWP) values used shall be those taken from the latest UN Intergovernmental Panel on Climate Change (IPCC) reports. For further guidance see Table XI.1. | | | | +| 7.2.5.2 | In general, data age and technological correlation are especially important in LCAs for ICT goods, networks and services due to the rapid technology evolution and the growth in network traffic. e.g., for data traffic, up-to-date data shall always be used. | | | | +| 7.2.5.2 | For support activities (e.g., ICT manufacturer support activities and operator support activities), primary data shall be used for all individual processes under the financial or operational control of the organization undertaking the LCA... | | | | +| 7.2.5.2 | ... and data shall be representative of the processes for which they are collected. | | | | +| 7.3.1.1 | Data shall be collected, for each unit process that is included within the system boundary, in accordance with Annex B. | | | | +| 7.3.1.1 | Data shall be collected for all mandatory processes outlined in Table 2. | | | | +| 7.3.1.1 | When data has been collected from public sources, the source shall be referenced. | | | | +| 7.3.1.2 | Data shall be collected at least for the processes marked with "mandatory" in Table 2, unless these are found negligible in accordance with the cut-off rules. | | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|-------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|----------------------|------------------------------------------------| +| 7.3.1.2.1 | It should be noted that, for many products (especially end-user goods), periods of idling and power off may be significant and are important to consider when modelling the traffic profile/ model the usage profile and shall be included if applicable. | | | | +| 7.3.1.4 | Use time, goods type, data traffic and network access type give important statistical data that needs to be collected in order to quantify the use of ICT systems. | | | | +| 7.3.1.2.3 | When calculating the potential environmental impact, the LCA practitioner is encouraged to use the most accurate data for the energy mix that is applicable to the ICT goods under assessment. In particular, the use stage shall use the applicable electricity mix to calculate the potential environmental impact from the use stage more exactly. | | | | +| 7.3.2.1 | The general requirements for data calculations in [ISO 14040] and [ISO 14044] shall be applied. | | | | +| 7.3.2.1 | All calculation procedures shall be explicitly documented and the assumptions made shall be clearly stated and explained. | | | | +| 7.3.2.1 | The same calculation procedures shall be consistently applied throughout the study. | | | | +| 7.3.2.1 | A check on data validity shall be conducted during the process of data collection to confirm that the data quality requirements for the intended application have been fulfilled. | | | | +| 7.3.2.3 | The evaluation of the environmental load shall consider both a fixed part which is independent of the usage and a variable part which correlates to the usage. | | | | +| 7.3.3.1 | The same allocation method shall be used for all environmental loads for all products from a common process. | | | | +| 7.3.3.1 | The study shall identify the processes shared with other product systems and deal with them according to the stepwise procedure presented below. | | | | +| 7.3.3.2 | Data for generic processes (G1 to G7) shall be allocated as a whole (i.e., for the full life cycle for the generic process) to the associated life cycle stage of the product system. | | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|-------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|----------------------|------------------------------------------------| +| 7.3.3.2 | However, all raw material acquisition (G5) shall be allocated to the life cycle stage Goods raw material acquisition (A). | | | | +| 7.3.3.3 | Data for relevant parts of the organization/operation shall be allocated to the relevant part of the product system life cycle. | | | | +| 7.3.3.3 | If no detailed information on organization/operation is available, the allocation shall be based on organizational or economic data. | | | | +| 7.3.3.8 | End-user goods (e.g., PCs, smart phones) which access more than one ICT network (e.g., 3G, WLAN) shall be allocated to these ICT networks based on use time. | | | | +| 7.3.3.8 | The assumptions regarding use time for access to different ICT networks and offline work shall be described and motivated. | | | | +| 7.3.3.8 | Impact from shared network resources (e.g., transmission goods, core nodes and data centres) shall be allocated to an access network based on data traffic. | | | | +| 7.3.3.8 | The assumptions regarding data traffic shall be described and motivated. | | | | +| 7.3.3.9 |

The impact from each ICT network supporting the service should be allocated to the service based on access use time or data traffic.

More specifically, the following allocation principle of ICT network data to an ICT service shall be used:

Data for end-user goods:

  • to be allocated based on active use time of the ICT service.

etc.

| | | | +| 7.3.3.9 | Data traffic is also preferred for e.g., mobile access networks as mobile access networks show a large dependency between data traffic and energy consumption and need a traffic model that takes data traffic into account. | | | | +| 7.3.3.9 |

Data for data centres and service provider activities:

  • The data centre(s) where the ICT service is operated as well as the service provider activities shall be allocated based on the number of subscriptions and service users or amount of data/transactions.
| | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|-------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|----------------------|------------------------------------------------| +| 8.2 | ISO states that the selection of impact categories shall reflect a comprehensive set of environmental issues related to the product system being studied, taking the goal and scope into consideration. | | | | +| 8.2 | In the LCA it shall be ensured that the inventory elementary flows (see Annex G) are correctly linked with appropriate LCIA characterization factors. | | | | +| 8.2 | For climate change, the most recent global warming characterization factors from the Intergovernmental Panel on Climate Change (IPPC) for each GHG shall be used and the timeframe should be 100 years. | | | | +| 8.2 | The midpoint category 'climate change' is mandatory. | | | | +| 8.2 | For other impact categories, there is no methodological consensus in the LCA community. Thus, the LCA practitioner shall decide which impact categories to consider and how to calculate them, based on the studied ICT product system and purpose of the LCA study. | | | | +| 8.2 | All impact categories and category indicators included shall be disclosed (Table L.10) and justified. | | | | +| 9.2 | The sources of uncertainty and methodological choices made shall be assessed and disclosed. | | | | +| 9.3 | The results of the LCI or LCIA phases shall be interpreted according to the goal and scope of the study. | | | | +| 9.3 | The interpretation shall include a sensitivity check of the significant inputs, outputs and methodological choices, and defined use scenarios, in order to understand the uncertainty of the results. | | | | +| 10.1 | The reporting of ICT product systems shall fulfil the reporting rules defined by [ISO 14040] and [ISO 14044]. | | | | +| 10.1 | In the case of reporting, a public GHG inventory report, the key accounting principles (relevance, accuracy, completeness, consistency, and transparency) shall be met. | | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------|---------------|-----------------------------------------| +| 10.1 |

In addition to the reporting obligations outlined by [ISO 14040] and [ISO 14044], the report shall include the following information:

  • • Contact information;
  • • Studied goods, networks and services product system name and description;
  • • Type of inventory (i.e., final product cradle-to-grave or intermediate product cradle-to-gate inventory);
  • • Goals of the study.

The reporting of results shall include:

  • • Total GHG emissions reported as amount of carbon dioxide equivalent (CO2e) per functional unit for ICT good, networks and services assessed;
  • • Percentage for each life cycle stage contributing to the total results;
  • • Electricity (with use stage separated from the other stages);
  • • Primary energy;
  • • Fuels;
  • • Value and sources of emission factors, clearly indicating their use, for CO2 and CO2e, and global warming potential (GWP) metric used in the report
  • • Other data, justifications and explanations as stated throughout this report.
| | | | +| 10.1 | In addition to the rules outlined in this clause and what is stated in Annex L shall be followed for reporting of studies claiming compliance with this Recommendation. | | | | +| 10.1 | The report shall contain a compliance statement indicating whether the LCA fully complies with this Recommendation (in case of full compliance) or whether the LCA partially complies with this Recommendation, with the exceptions transparently listed and justified (partial compliance). | | | | +| 10.1 | The extent to which support activities and other optional/recommended activities are excluded from different parts of the life cycle shall be clearly described and, for recommended activities, also motivated in the study report. | | | | +| 10.1 | For each product system (including ICT goods, networks and services), the following aspects, which are particularly important for ICT solutions, shall be | | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|-------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|----------------------|------------------------------------------------| +| | transparently justified and described in accordance with the principles defined in this clause:
Operating lifetime: All lifetime assumptions shall be stated and justified. | | | | +| 10.1 | Cut-off: Any cut-off made shall be clearly stated and justified. | | | | +| 10.1 | Allocations: Basis for allocations made shall be described, especially for recycling, use of recycled materials, distribution of facility data and support activities. | | | | +| 10.1 | Data sources: Data sources (i.e., primary/secondary) shall be clearly stated, and deviations from Table 2 shall be justified. | | | | +| 10.1 | For each product system (including ICT goods, networks and services), an additional diagram shall be presented when optional activities in Table 2 are included. | | | | +| 10.1 | The emission factors used shall be clearly stated. The source used and the year they represent shall be clearly stated. | | | | +| 10.1 | In the case of emission factors for grid electricity, the source, year and location (specific, country, global average) shall be clearly stated. | | | | +| 10.1 | Where emission factors are sourced from non-public sources, or are not the most recent, a justification for their use shall be provided. | | | | +| 10.2.1 | For each impact category studied, diagrams corresponding to Figures 14a and 14b shall be reported for the corresponding category indicator result. | | | | +| 10.2.1 | Due to the importance of operating lifetime to results, information regarding this element shall always be included in the diagram, along with some other basic modelling statements, such as the result for the indicator, LCA study year operating lifetime, etc. as shown below. | | | | +| 10.2.1 | Figure 14b shall be presented whenever optional activities/processes from Table 2 have been included in the studied product system. | | | | +| 10.2.1 | For transport, the total result including all transport throughout the life cycle (Table L.4) shall be stated in the immediate proximity of the diagram (Figures 14a and 14b). | | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|-------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|----------------------|------------------------------------------------| +| 10.2.1 | If used data sets do not report all transport used separately, any missing transport shall be listed and justified. | | | | +| 10.2.1 | Figure 16 shall be accompanied by the disclaimer "This LCA result cannot be compared to the result of another LCA unless all assumptions and modelling choices are equal". | | | | +| 10.2.1 | A diagram summarizing distribution of selected environmental impact category indicators between life cycle stages shall be prepared together with absolute figures as shown in the Annex L (Table L.10). | | | | +| 10.2.1 | Figure 16 shall be accompanied by the disclaimer "This LCA result cannot be compared to the result of another LCA unless all assumptions and modelling choices are equal". See further explanation in the scope. | | | | +| 10.2.2.1 | Any deviation from Table 2 and clause 7.2.3 with respect to mandatory life cycle stages/unit processes shall be clearly stated and justified. | | | | +| 10.2.2.1 | Additionally, the inclusion of generic processes for the different life cycle stages shall be clearly stated and reported. | | | | +| 10.2.2.1 | Deviations for generic processes shall be reported according to Annex L (Table L.3). | | | | +| 10.2.2.2 | The use of raw materials shall be transparently reported as outlined below. | | | | +| 10.2.2.2 | The most important metals from recycling point of view shall always be stated. For an appropriate reporting format refer to Annex L (Table L.5). | | | | +| 10.2.2.2 | Deviation(s) from the requirements shall be clearly justified and reported. | | | | +| 10.2.2.3.1 | Compliance with Annex E (Table E.1) shall be reported and any deviation shall be described and justified. For an appropriate reporting format refer to Table L.6. | | | | +| 10.2.2.4.1 | The model of distribution over time of different usage modes including power off and idle and the rationale for those shall be transparently reported. For an appropriate reporting format refer to Annex L (Table L.7). | | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|-------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|----------------------|------------------------------------------------| +| 10.2.2.4.2 | The basis and rationale for the energy consumption values for the support goods use shall be transparently described and justified. For an appropriate reporting format, refer to Annex L (Table L.7). | | | | +| 10.2.2.5 | If EoLT is included, any deviations from Annex F shall be transparently reported and justified. For an appropriate reporting format, refer to Annex L (Table L.8). | | | | +| 10.2.3 | For LCI, the following items shall be reported transparently: total use of primary energy and electricity. | | | | +| 10.2.3 | Additionally, results for elementary flows according to Annex G (Table G.1) could be transparently reported on an optional basis. If such reporting is not made, it is mandatory to describe unexpected results, lack of data, and other findings associated with the elementary flows. | | | | +| 10.3.2 | Operating lifetime is also important for networks and is associated with the lifetime of the different nodes, which shall be reported. | | | | +| 10.3.2 | It shall be reported following the format of Annex L (Table L.11), which also describes the studied network. | | | | +| 10.3.2 | Figure 18 shall be accompanied by the disclaimer "This LCA result cannot be compared to the result of another LCA unless all assumptions and modelling choices are equal". | | | | +| 10.3.2 | Additionally, a diagram summarizing the distribution of environmental impact category indicators between life cycle stages shall be prepared together with absolute figures, as shown in the Annex L (Table L.10). | | | | +| 10.3.2 | Figure 19 shall be accompanied by the disclaimer "This LCA result cannot be compared to the result of another LCA unless all assumptions and modelling choices are equal". | | | | +| 10.3.2 | Details of network energy consumption shall be reported with a split of different elements of the network. An example of table for reporting is provided in Table L.12. | | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|-------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|----------------------|------------------------------------------------| +| 10.4.2 | Operating lifetime is important also for services, but it is associated with the lifetime of the different nodes, which shall be reported. | | | | +| 10.4.2 | Allocation of network data to the service shall be reported. It should be reported according to Annex L (Table L.13). | | | | +| 10.4.2 | Additionally, a diagram summarizing the distribution of impact category indicators between life cycle stages for the service product system under study shall be presented together with absolute figures, as shown in Table L.10. | | | | +| 10.4.2 | Figure 23 shall be accompanied by the disclaimer "This LCA result cannot be compared to the result of another LCA unless all assumptions and modelling choices are equal". | | | | +| 11 | Any critical review shall be performed according to the requirements of [ISO 14040] and [ISO 14044] and those contained in this Recommendation. | | | | +| 11 | The scope and type of critical review desired shall be defined in accordance with [ISO 14044] clauses 4.2.3.8 and 6. | | | | +| 12.1 | Infrastructure, e.g., highways for transportation, is generally assumed to exist independently of the introduction of new services and shall be excluded. | | | | +| 12.1 | The handling of time perspective and scale shall be disclosed and justified in the report. | | | | +| 12.1 | To quantify the net environmental impact when introducing an ICT solution, the environmental impact of both the ICT product system itself and the reference product system shall be assessed from a life cycle perspective. | | | | +| 12.1 | To ensure that the comparative assessment gives a relevant result, the full life cycle of both systems shall always be considered | | | | +| 12.1 | From an LCA perspective, the reference product system and the ICT product system shall mimic each other as far as possible... | | | | +| 12.1 | ...and the LCA practitioner shall model both systems in an unbiased way. | | | | +| 12.2 | Goods shall be compared with each other, | | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|-------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|----------------------|------------------------------------------------| +| 12.2 | ICT networks shall be compared with each other. | | | | +| 12.2 | ICT services shall be compared with each other. | | | | +| 12.3.1 | In this comparative LCA study, the scope of the LCA study shall be defined in such a way that the two systems can be compared. | | | | +| 12.3.1 | Systems shall be compared using the same functional unit and equivalent methodological considerations, such as performance, system boundary, data quality, allocation procedures and cut-off rules. | | | | +| 12.3.1 | Any differences between systems regarding these parameters shall be identified and reported. | | | | +| 12.3.2 | Also in this case, the scope of the LCA study shall be defined in such a way that the two systems can be compared. | | | | +| 12.3.2 | Both systems shall be assessed using the same functional unit and equivalent methodological considerations, such as system boundary, data quality, allocation procedures and cut-off rules. | | | | +| 12.3.2 | Any differences between systems regarding these parameters shall be identified and reported. | | | | +| 12.3.3 | The assessment of the ICT-based system shall be performed in accordance with Part I. | | | | +| 12.3.3 | When making comparisons, it is important to keep in mind that the functional unit used shall be applicable to both the reference product system and the system of ICT goods, networks and services. | | | | +| 12.3.3 | For the reference product system, applicable requirements in this Recommendation shall be applied, e.g., requirements regarding data quality, cut-off, etc. | | | | +| 13.2 | All the requirements stipulated in Part I for a system boundary definition shall be applied. | | | | +| 13.2.1 | The functional unit shall take into account the general rules outlined in Part I, clause 7.2.2 and [ISO 14044] clause 4.2.3.2. | | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|-------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|----------------------|------------------------------------------------| +| 13.2.1 | Additionally, the functional unit shall be defined so that it is applicable both to the ICT goods, networks and services product system and the reference product system. | | | | +| 13.2.1 | The reference flow shall be defined to quantify the functional unit. | | | | +| 13.2.1 | In other words, for the functional unit of one meeting, for instance, the reference flow for the systems of ICT goods, networks and services and the reference product system shall be defined. | | | | +| 13.2.2 | Two different system boundaries shall be defined which are applicable for the ICT goods, networks and services product system and for the reference product systems, respectively. | | | | +| 13.2.2 | Considerations shall be made to which electricity is used when assessing the environmental impact of the ICT goods, networks and services product system and the reference product systems. | | | | +| 13.3 | The calculation for the inventory analysis shall be performed in accordance with Part I, clause 7.3. | | | | +| 13.4 | The life cycle impact assessment is to be performed in accordance with Part I, clause 8. | | | | +| 14 | Any cut-off made during a study shall be clearly stated in the study report, e.g., the exclusion of life cycle processes which are considered insignificant should be justified. | | | | +| Annex B | A mandatory list of generic activities (unit processes) that have been found to be of importance for an LCA of ICT goods, networks and services can be found in Annex D. | | | | +| Annex B | The following emissions shall be taken into account if applicable to the studied impact category(ies):
  • • emissions to air
  • • emissions to water
  • • emissions to soil.
| | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in ITU-T L.1410 | Requirement | Fulfilled | Not fulfilled | Explanation/Motivation if not compliant | +|-------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|----------------------|------------------------------------------------| +| Annex B | The following resource objects shall be taken into account, if applicable, to the studied impact category(ies):
  • • material resource use (or material depletion)
  • • energy resource use (or energy resources depletion).
| | | | +| Annex B | A list of emissions and resource objects that shall be included, if applicable to the studied product system and impact category(ies), can be found in Annex G (Table G.1). | | | | +| Annex B | Furthermore, the following inputs shall also be included, if applicable, to the studied impact category(ies):
  • • electricity;
  • • other forms of delivered energy (district heating and cooling);
  • • fuels (typically indicates the fuels are incinerated on-facility or in a vehicle connected to the facility);
  • • primary products (products that are part of the final product in operation);
  • • secondary products (products that are not part of the final product in operation);
  • • transport, travel, and other services (can be seen as a special non-material secondary product input).
| | | | +| Annex B | Finally, the following flows shall also be included, if applicable, to the studied impact category(ies):
  • • water discharge (to municipal sewage or recipient);
  • • waste fractions (residual waste fractions or waste fractions that need further treatment, also including material recycling and energy recovery);
  • • product output (the main purpose with the unit process or activity).
| | | | +| Annex C | Any support activities included in the LCA scope shall be clearly reported in terms of organization activities considered. | | | | +| Annex D | G7.... Other material shall be considered. | | | | +| Annex E | Table E.1 lists the applicable parts and assembly types which shall be taken into account when performing an LCA of ICT goods, if applicable, to the ICT good (not | | | | + +**Table XII.1 – Summary of the requirement of this Recommendation** + +| Clause in
ITU-T L.1410 | Requirement | Fulfilled | Not
fulfilled | Explanation/Motivation
if not compliant | +|-----------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|--------------------------|----------------------------------------------------| +| | ICT network). It also lists the corresponding part, assembly categories and unit processes. | | | | +| Annex G | Table G.1 contains elementary flows which shall be taken into account in LCA analyses for ICT. | | | | +| Annex G | The substance names listed in Table G.1 shall be used in the report. | | | | +| Annex G | Deviation(s) from the requirements shall be clearly motivated and reported. | | | | +| Annex H | Table H.1 lists the minimum raw material groups (chemicals, fuels, metals, plastics, packaging materials, and additives) which shall be taken into account in LCAs of ICT goods, if applicable to the studied ICT product system. | | | | +| Annex L | This annex contains tables that shall be used to report the result of the assessment. | | | | +| Annex L | Deviation(s) from the requirements shall be clearly motivated and reported. | | | | + +## Appendix XIII + +### The relation between LCA and Circular Economy for ICT + +(This appendix does not form an integral part of this Recommendation.) + +The present document, as along with other leading LCA standards such as [ISO 14044], can handle LCA modelling of different material efficiency practices to some extent, allowing for the assessment of potential benefits and drawbacks within the system at hand. It is possible to use the present document as framework for deriving the very different LCA profiles of ICT goods. + +The common understanding is that LCA can handle some aspects of circularity, but other tools are useful to provide a wider understanding [b-Walzberg]. LCA alone may not always be enough to study circular economy strategies. LCA should be combined with other method from industry ecology, complex systems science and circularity indicators. + +The trend is that traditional LCAs are complemented by circularity measurements key performance indicators like product circularity indicator [b-Walzberg], [b-Bracquené], [b-ITU-T L.1023] or whichever circularity indicator choses by the LCA practitioner to evaluate the resource effectiveness of the product system at hand. + +For goods environmental footprint, LCA is the recommended tool. The LCA practitioner needs to make suitable assumptions to use LCA for goods which is refurbished and reused. LCA based on [ISO 14044] has been used in the ICT sector to study the effect of extending product lifetimes [b-Zink], [b-Prakash], [b-Proske], [b-André] and ITU-T L.1410 provides further guidance for assessing the effect of multiple (re)uses of the goods. + +The conclusion is that the present standard can be used to evaluate the effect of some main circularity aspects if all assumptions, especially regarding system boundary and functional unit, are shown. + +## Appendix XIV + +### Application scenarios for LCA of ICT goods with extended operating lifetime and multiple life cycles + +(This appendix does not form an integral part of this Recommendation.) + +ICT goods can undergo several forms of extension of operating lifetime, e.g., reuse or refurbishment, sometimes with the change of ownership. Products that are reused or refurbished will enter a new life cycle as part of extended operating lifetime. LCA is useful for different analysis purposes for these ICT goods. Depending on the goal of the LCA study, some potential application scenarios for LCA are e.g.: + +- Cradle-to-grave LCA of a ICT goods with extended operating lifetime +- LCA of first life cycle of a ICT goods with multiple life cycles +- LCA of second life cycle of a ICT goods with multiple life cycles +- Comparative LCA of a ICT goods with extended operating lifetime. + +This is not an exhaustive list of potential application scenarios of LCA use. However, it illustrates the dynamic nature of LCA's applicability and approach required, depending on the intended use of LCA results, end of life scenarios selected, operating lifetime, and the respective life cycle(s) of the ICT goods. + +The above listed application scenarios are further explained in the following section. + +### XIV.1 LCA covering cradle-to-grave of a ICT goods with extended operating lifetime + +The purpose of a LCA covering cradle-to-grave is to evaluate the environmental impact across the entire life of the goods, from raw material acquisition to the final waste treatment. LCA covering cradle-to-grave can be used as one of the product development and improvement tools to study the differences in the environmental impact of design choices and the resulting environmental impact reduction due to reduction of material and energy consumption, supply chain optimization, different end-of-life treatment scenarios and extended operating lifetime of the goods. It helps to assess and report the environmental impact of ICT goods, identify hotspots and opportunities for improvement in product design to manufacture more sustainable products. + +As the name suggests, the scope of LCA covering cradle-to-grave covers the entire life cycles of the goods, starting from raw material acquisition to the final end-of-life, typically incorporating multiple life cycles through reuse and refurbishment. LCA covering cradle-to-grave of ICT goods can be done by redefining the functional unit to incorporate extended operating lifetime. Both goods with single life cycle and multiple life cycles can be assessed with this approach. + +### XIV.2 LCA of first life cycle of ICT goods with multiple life cycles + +LCA can be used to assess the environmental impact of first life cycle of ICT goods with extended operating lifetime. These ICT goods facilitate recirculating the product and materials back to the system at the end of their use, creating a closed-loop system where goods at their highest level and materials are continually kept in use and recycled instead of being discarded after the first use. Multiple reuse and refurbishment cycles of a product are possible after the first use. Products that are reused or refurbished will enter a new life cycle as a part of an extended operating lifetime and LCA of second life cycle is used to assess the environmental impact of new life cycle. + +The scope of LCA of first life cycle of ICT goods includes cradle-to- (which includes "A Goods raw material acquisition", "B Production", "C Use" and "D EoLT" (partial) stages of first life), after this point the product enters a new life cycle. + +For a transparent assessment analysis of the environmental impact of ICT goods, it is important to separate the impact into correct life cycles and life cycle stages. The assessment of the first life cycle environmental impact can be done when the product is returned for reuse or refurbishment after its first use. + +### **XIV.3 LCA of second life cycle of a ICT goods with multiple life cycles** + +LCA can be used to assess the environmental impact of the second life cycle of ICT goods with extended operating lifetime. When goods are returned after its first use for refurbishment and/or for reuse, needed actions are performed for the goods to enter the second use with extended operating lifetime. Refurbishment involves preparing the goods for a second use with necessary actions, e.g., replacing needed parts in the goods. + +The scope of this assessment approach covers the period from the end of the first life cycle (which is the start of the second life cycle) until the end of the second life cycle or from the start of the second life cycle to its grave (which includes "B Production, "C Use" and "D EoLT" stages of second life). The environmental impact due to refurbishment of the goods, including the parts production of newly added parts and delivery of the goods after refurbishment for the second use, is also considered for the LCA of second life cycle of a ICT goods. + +This assessment can be best performed when the goods are returned after its first use. This approach is particularly useful for the environmental impact assessment of refurbished or reused goods when ownership of the goods changes. It also gives indication of the benefit of reuse or refurbishment compared to new goods. + +### **XIV.4 Comparative LCA of a ICT goods with extended operating lifetime** + +The purpose of comparative LCA as described in Part II is to compare the environmental impact of two or more products, offering the same or similar function usually to identify the one with lower environmental impact. It helps to identify the trade-offs and potential intended and unintended consequences of different choices made during design and production processes. Comparative LCA of ICT goods can be done by comparing the environmental impact of ICT goods with extended operating lifetime, to the appropriate number of new goods with combined operating lifetime equal to the extended operating lifetime. To ensure relevant and representative results with the comparative LCA, the system boundaries need to be identical, the same functional unit needs to be applied and equal operating lifetime of the compared product systems need to be included in the assessment, etc. The condition for comparability is further defined in Part II and in the Scope. + +Depending on the intended use of the comparative LCA results, it is also a common practice to exclude the stages and processes that are identical across the compared functional units and only include the relevant life cycle stages and processes. Therefore, the scope of comparative LCA could be a cradle-to-grave, cradle-to-gate, gate-to-grave, cradle-to-end of first life cycle, start of the next life cycle to end of the next life cycle, or start of the last life cycle-to-grave, etc. + +Comparative LCA can be used to compare the environmental impact of ICT goods with extended operating lifetime to a relevant number of new goods, LCA of second life cycle of a ICT goods with extended operating lifetime compared to a new good, or impact of ICT goods compared to a non-ICT system using the same functional unit, operating lifetime, system boundaries, and other equivalent methodological considerations for both systems. See Part II of ITU-T L.1410 for more information about comparative LCA. + +## Appendix XV + +### Example analysis of different refurbishment configurations + +(This appendix does not form an integral part of this Recommendation.) + +This appendix provides an example analysis using comparative LCA when assessing refurbished products. + +The consequences of different refurbishment configurations are analysed in [b-ADEME], which studied the cases of smartphones, fixed PCs, mobile PCs and tablets. + +This report accounts not only the carbon impacts, but also the impacts on depletion of abiotic resources (mineral, metal, fossil resources), acidification and the ionizing radiation emitted. + +Regarding the impact in terms of greenhouse gas emissions, [b-ADEME] provides the graph below, which shows the impact of smartphones depending on the frequency of purchase and considering a depreciation approach. + +As indicated in in [b-ADEME]: "this approach involves transferring and depreciating some of the impacts of manufacturing and end of life of the new device to the refurbished product, if refurbishment takes place before the theoretical end of the usage period in the first cycle." In the report, the observed average lifespan of new smartphones is 3 years, and two years for refurbished ones (Table 27). It also indicates that the average global warming potential over the entire life cycle of a new smartphone is 85.2 kgCO2e, and that of refurbishing operations is 7.61 kgCO2e. Figure XV.1 shows a comparison of GHG emissions from the reference smartphone, using the depreciation approach, over a 6-year market period. + +![Line graph showing GHG emissions (kg eq. CO2) over a 6-year market period for different smartphone purchase and refurbishment configurations. The configurations include regular purchase of recent refurbished phones, regular purchase of old refurbished phones, reasonable purchase of old refurbished phones, reasonable use of a new smartphone, virtuous use of a new smartphone, and systematic purchase of new offers. The systematic purchase of new offers shows the highest emissions, reaching over 500 kg eq. CO2 by Year 6.](b3348d6f948fe54e04f1a7bf7e86ec75_img.jpg) + +The graph displays the cumulative GHG emissions (kg eq. CO2) for six different smartphone usage scenarios over a 6-year period. The y-axis ranges from 0 to 600 kg eq. CO2 in increments of 100. The x-axis shows years from Year 0 to Year 6. The scenarios are: 1) Regular purchase (Every 2 years) of recent refurbished (1 year) - yellow line; 2) Regular purchase (Every 2 years) of 2 old refurbished - dark blue line; 3) Reasonable purchase (Every 3 years) of old refurbished (more than 3 years) - light blue line; 4) Reasonable use (3 years) of new smartphone - dark green line; 5) Virtuous use (6 years) of a new smartphone - light green line; 6) Systematic purchase (Every year) of new offers - orange line. The orange line shows a steady increase, reaching approximately 510 kg eq. CO2 by Year 6. The other lines show much lower emissions, with the light green line (Virtuous use) reaching approximately 190 kg eq. CO2 by Year 6. + +| Year | Regular purchase (Every 2 years) of recent refurbished (1 year) | Regular purchase (Every 2 years) of 2 old refurbished | Reasonable purchase (Every 3 years) of old refurbished (more than 3 years) | Reasonable use (3 years) of new smartphone | Virtuous use (6 years) of a new smartphone | Systematic purchase (Every year) of new offers | +|--------|-----------------------------------------------------------------|-------------------------------------------------------|----------------------------------------------------------------------------|--------------------------------------------|--------------------------------------------|------------------------------------------------| +| Year 0 | 0 | 0 | 0 | 0 | 0 | 0 | +| Year 1 | 30 | 10 | 5 | 20 | 15 | 90 | +| Year 2 | 60 | 20 | 10 | 40 | 30 | 170 | +| Year 3 | 90 | 30 | 15 | 60 | 45 | 250 | +| Year 4 | 120 | 40 | 20 | 80 | 60 | 330 | +| Year 5 | 150 | 50 | 25 | 100 | 75 | 410 | +| Year 6 | 180 | 60 | 30 | 120 | 90 | 490 | + +Line graph showing GHG emissions (kg eq. CO2) over a 6-year market period for different smartphone purchase and refurbishment configurations. The configurations include regular purchase of recent refurbished phones, regular purchase of old refurbished phones, reasonable purchase of old refurbished phones, reasonable use of a new smartphone, virtuous use of a new smartphone, and systematic purchase of new offers. The systematic purchase of new offers shows the highest emissions, reaching over 500 kg eq. CO2 by Year 6. + +L.1410(24) + +Figure XV.1 – Comparison of reference smartphone – depreciation approach – 6 year market results for GHG emissions + +The document mentions that the impact of refurbishment, taking into account the depreciation period of the first lifespan, is calculated as follows: + +$$\begin{aligned} Impact_{refurbished} &= \frac{(Impact_{remaining\ to\ be\ imputed\ 1st\ life\ new} + Impact_{refurbishment})}{Usage\ period_{refurbished}} \\ &+ Impact_{annual\ usage} \end{aligned}$$ + +Where: + +$$\begin{aligned} Impact_{remaining\ to\ be\ imputed\ 1st\ life\ new} &= \frac{(Impact_{manufacturing+end\ of\ life\ new})}{D_{1hypothesis}} \times (D_{1hypothesis} - D_{1real}) \end{aligned}$$ + +$D_{1hypothesis}$ = Usage period in the theoretical first lifetime observed on the market + += Usage period beyond which it can be considered that refurbishment automatically extends the lifespan + +$D_{1real}$ = Usage period in the actual first lifespan + += Usage period prior to collection and change of owner + +For example, buying a recent (1 year old) refurbished device every two years will have a CO2e impact slightly higher than the average use of buying a new smartphone every 3 years, due to refurbishing operations, even if the lifespans of smartphones are the same (Figure XV.1). The lowest impacts are reached by increasing the average lifespan of new devices, as illustrated in cases called "regular" and "reasonable" purchase (blue dotted lines), where the lifespans of devices are respectively 4 and 6 years. + +Therefore, to assess the environmental effects of the existence of a refurbishing process, at least the following three effects should be part of the assessment: + +- i) the impact of refurbishing operations (repair, transport, marketing, raw materials, etc.) in each life cycle stages, +- ii) the effect of previous equipment life(s), as early refurbishment accelerates the replacement of the equipment with one that is new, +- iii) the operating lifetimes of the compared product systems are equal. + +## Bibliography + +- [[b-ITU-T L.1022](#)] Recommendation ITU-T L.1022 (2019), *Circular economy: Definitions and concepts for material efficiency for information and communication technology*. +- [[b-ITU-T L.1023](#)] Recommendation ITU-T L.1023 (2023), *Assessment method for circularity performance scoring*. +- [[b-ITU-T L.1310](#)] Recommendation ITU-T L.1310 (2024), *Energy efficiency metrics and measurement methods for telecommunication equipment*. +- [[b-ITU-T L.1440](#)] Recommendation ITU-T L.1440 (2015), *Methodology for environmental impact assessment of information and communication technologies at city level*. +- [[b-ITU-T L.1480](#)] Recommendation ITU-T L.1480 (2025), *Enabling the Net Zero transition: Assessing how the use of information and communication technology solutions impacts greenhouse gas emissions of other sectors*. +- [[b-ITU-T L-Suppl.60](#)] Supplement 60 to ITU-T L-series Recommendations (2024), *Example of a life cycle assessment (LCA) of a mobile phone*. +- [b-ADEME] ADEME (2022), *Evaluation de l'impact environnemental d'un ensemble de produits reconditionnés* (Assessment of the environmental impact of a set of refurbished products). + +- [b-André] André, H., Söderman, M. L., & Nordelöf, A. (2019). *Resource and environmental impacts of using second-hand laptop computers: A case study of commercial reuse*. *Waste Management*, 88, 268-279. + +- [b-Bracquené] Bracquené, E., Lindemann, J., & Duflou, J. (2022). *Implementation of circularity indicators in a household product manufacturing company*. *Procedia CIRP*, 105, 660-665. + +- [b-CLC TR 45550] CEN/CENELEC TR 45550:2020, *Definitions related to material efficiency*. +- [b-EC common methods] European Commission – Joint Research Centre (2012), *Product Environmental Footprint (PEF) Guide. Deliverable 2 and 4A of the Administrative Arrangement between DG Environment and the Joint Research Centre No N 070307/2009/552517, including Amendment No 1 from December 2010*, Ispra, Italy. +- [b-ETSI TS 103 199] ETSI TS 103 199 (2011) *Environmental Engineering (EE); Life Cycle Assessment (LCA) of ICT equipment, networks and services; General methodology and common requirements*, V.1.1.1. +- [b-ETSI ES 203 199] ETSI ES 203 199 (2024), *Environmental Engineering (EE); Methodology for environmental Life Cycle Assessment (LCA) of Information and Communication Technology (ICT) goods, networks and services*, V.1.4.0. +- [b-ETSI EN 303 808] ETSI EN 303 808 (2022), *Environmental Engineering (EE); Applicability of EN 45552 to EN 45559 methods for assessment of material efficiency aspects of ICT network infrastructure goods in the context of circular economy*. + +- [b-ETSI TS 202 336-1] ETSI TS 202 336-1 (2011), *Environmental Engineering (EE);Monitoring and Control Interface for Infrastructure Equipment (Power, Cooling and Building Environment Systems used in Telecommunication Networks) Part 1: Generic Interface, V.1.2.1.* +- [b-ETSI TS 102 706] ETSI TS 102 706 (2013), *Environmental Engineering (EE) Energy Efficiency of Wireless Access Network Equipment, V1.3.1.* +- [b-EUR 24708 EN] EUR 24708 EN (2010), *International Reference Life Cycle Data (ILCD) System Handbook: General guide for Life Cycle Assessment – Detailed guidance*, 1st edition., European Commission Joint Research Centre. +- [b-EUR 24586 EN] EUR 24586 EN (2010), *International Reference Life Cycle Data System (ILCD) Handbook: Framework and requirements for Life Cycle Impact Assessment models and indicators*, 1st edition. European Commission Joint Research Centre. +- [b-EUR 25167 EN] EUR 25167 EN (2012), *Characterisation factors of the ILCD Recommended Life Cycle Impact Assessment methods* (20/02/2013 updated). +- [b-GHG Protocol CS] Greenhouse Gas Protocol Corporate Standard (2004), *A Corporate Accounting and Reporting Standard.* +- [b-GHG Protocol CVCS] Greenhouse Gas Protocol Corporate Standard (2011), *Corporate Value Chain (Scope 3) Accounting and Reporting Standard.* +- [b-IPCC] IPCC Climate Change (2013), *Appendix 8.A: Lifetimes, Radiative Efficiencies and Metric Values, Table 8.A.1 p 731-738*. Myhre, G., D. Shindell, F.-M. Bréon, W. Collins, J. Fuglestvedt, J. Huang, D. Koch, J.-F. Lamarque, D. Lee, B. Mendoza, T. Nakajima, A. Robock, G. Stephens, T. Takemura and H. Zhang, 2013: *Anthropogenic and Natural Radiative Forcing. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change* [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. +- [b-ISO 14046] ISO 14046:2014, *Environmental management – Water footprint – Principles, requirements and guidelines.* +- [b-Prakash] Prakash, S., Köhler, A., Liu, R., Stobbe, L., Proske, M., & Schischke, K. (2016, September). *Paradigm shift in Green IT-extending the life-times of computers in the public authorities in Germany*. In 2016 Electronics Goes Green 2016+(EGG) (pp. 1-7). IEEE. + +- [b-Proske] Proske, M., Clemm, C., & Richter, N. (2016). *Life cycle assessment of the Fairphone 2*. Fraunhofer IZM. +[https://www.fairphone.com/wp-content/uploads/2020/07/Fairphone\\_3\\_LCA.pdf](https://www.fairphone.com/wp-content/uploads/2020/07/Fairphone_3_LCA.pdf) +- [b-UNFCCC] United Nations (1992). *United Nations framework convention on climate change* +[https://unfccc.int/files/essential\\_background/background\\_publications\\_htmlpdf/application/pdf/convening.pdf](https://unfccc.int/files/essential_background/background_publications_htmlpdf/application/pdf/convening.pdf) +- [b-Walzberg] Walzberg, J., Lonca, G., Hanes, R. J., Eberle, A. L., Carpenter, A., & Heath, G. A. (2021). *Do we need a new sustainability assessment method for the circular economy? A critical literature review. Frontiers in Sustainability*, 1, 620047. + + +[b-Zink] + +Zink, T., Maker, F., Geyer, R., Amirtharajah, R., & Akella, V. (2014). *Comparative life cycle assessment of smartphone reuse: repurposing vs. refurbishment*. The International Journal of Life Cycle Assessment, 19, 1099-1109. + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|----------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1420-201202-I_PDF-E/e8ba5d4a3a22e24e44f7935ea26afcb0_img.jpg b/marked/L/T-REC-L.1420-201202-I_PDF-E/e8ba5d4a3a22e24e44f7935ea26afcb0_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..dad02182b30e94f721c7f50726f60641c96df521 --- /dev/null +++ b/marked/L/T-REC-L.1420-201202-I_PDF-E/e8ba5d4a3a22e24e44f7935ea26afcb0_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:45bf920a7798c0111eed0c87f3f277105f8935167814eaedd42f96a3f983bba0 +size 4024 diff --git a/marked/L/T-REC-L.1420-201202-I_PDF-E/raw.md b/marked/L/T-REC-L.1420-201202-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..124cd61745a68208f9cff7387f94e40311f7445d --- /dev/null +++ b/marked/L/T-REC-L.1420-201202-I_PDF-E/raw.md @@ -0,0 +1,939 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.1420** + +(02/2012) + +SERIES L: CONSTRUCTION, INSTALLATION AND +PROTECTION OF CABLES AND OTHER ELEMENTS OF +OUTSIDE PLANT + +--- + +**Methodology for energy consumption and +greenhouse gas emissions impact assessment +of information and communication technologies +in organizations** + +Recommendation ITU-T L.1420 + + + +# **Recommendation ITU-T L.1420** + +# **Methodology for energy consumption and greenhouse gas emissions impact assessment of information and communication technologies in organizations** + +## **Summary** + +Recommendation ITU-T L.1420 presents the methodology to be followed if an organization intends to claim compliance with this Recommendation when assessing its information and communication technology (ICT) related energy consumption and/or greenhouse gas (GHG) emissions. + +This Recommendation can be used to assess energy consumption and GHG emissions generated over a defined period of time for the following purposes: for assessment of related impact from ICT organizations or for assessment of impact from ICT related activities within non-ICT organizations. + +## **History** + +| Edition | Recommendation | Approval | Study Group | +|---------|----------------|------------|-------------| +| 1.0 | ITU-T L.1420 | 2012-02-06 | 5 | + +## **Keywords** + +ICT, assessment, energy consumption, greenhouse gases, GHG, scope 1, scope 2, scope 3, direct GHG emissions, energy indirect GHG emissions, other indirect GHG emissions + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2012 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|---------------------------------------------------------------------------------------------------------------------------------------------|-------------| +| 1 Scope ..... | 1 | +| 1.1 Assessment of impact from the use of ICT in non-ICT organizations..... | 1 | +| 1.2 Assessment of impact from ICT organizations ..... | 1 | +| 2 References..... | 2 | +| 3 Definitions ..... | 2 | +| 3.1 Terms defined elsewhere ..... | 2 | +| 3.2 Terms defined in this Recommendation..... | 3 | +| 4 Abbreviations and acronyms ..... | 4 | +| 5 Conventions ..... | 4 | +| 6 Principles of organizational assessment ..... | 4 | +| 7 Evaluation of energy consumption and GHG impact of ICT activities in non-ICT organizations..... | 5 | +| 7.1 Use of the Recommendation ITU-T L.1410 to assess the impact from the use of ICT in organizations ..... | 5 | +| 7.2 Aggregation of impacts from ICT goods, networks and services at an organizational level ..... | 5 | +| 7.3 Organizational boundaries..... | 6 | +| 7.4 Operational boundaries..... | 6 | +| 8 Evaluation of energy consumption and GHG impact of ICT organizations ..... | 7 | +| 8.1 General ..... | 7 | +| 8.2 Energy and GHG inventory design and development..... | 7 | +| 8.3 Quantification of energy consumption and GHG emissions..... | 8 | +| 8.4 Annual assessment..... | 12 | +| 8.5 Establishment of base-year energy and GHG inventory ..... | 12 | +| 8.6 Assessing and reducing uncertainty ..... | 13 | +| 8.7 Energy and GHG inventory quality management ..... | 13 | +| 8.8 Reporting of energy and GHG inventory ..... | 14 | +| 9 Organization's role in verification activities..... | 16 | +| Annex A – List of goods to be considered when assessing the impact of ICT activities in organizations..... | 17 | +| Annex B – Information to be provided in the GHG emission and energy report on scope 1 and scope 2 GHG emissions and energy consumption..... | 18 | +| Appendix I – Indirect GHG emissions categories ..... | 20 | +| Appendix II – Examples of organizational activities to reduce GHG emissions and energy consumption..... | 23 | +| Bibliography..... | 25 | + +# Introduction + +This Recommendation assists organizations in assessing the energy consumption and greenhouse gas (GHG) emissions related to their operations. It provides the necessary knowledge to prepare inventories and meet the societal demands emerging from a low-carbon economy and the challenge of higher energy prices. + +The Recommendation focuses on the energy consumption and GHG emissions resulting from ICT activities and ICT organizations. + +This Recommendation covers + +- The assessment of the life cycle perspective environmental impact of ICT goods, networks and services used by a non-ICT organization ("ICT in organizations"), e.g., PCs, servers, data centers and networks within the organizations premises, based on the Recommendation ITU-T L.1410 and an aggregation to an organizational level for first and second order effects. +- The assessment of the environmental impact of an ICT organization ("ICT organizations") based on [ISO 14064-1] and [b-GHG Protocol]. +- The interpretation of these impacts. +- The reporting of these impacts in a transparent manner. + +# Methodology for energy consumption and greenhouse gas emissions impact assessment of information and communication technologies in organizations + +# 1 Scope + +The increasing proliferation of information and communications technology (ICT) has led to concerns regarding its environmental impact. Taking into consideration the ongoing efforts within the United Nations Framework Convention on Climate Change (UNFCCC) to combat climate change, ITU-T decided to develop an internationally agreed upon methodology to help the ICT Sector to make an inventory of the environmental impact, including greenhouse gas emissions and energy consumption, of ICTs in organizations. + +This Recommendation can be used to assess the energy consumption and GHG emissions of ICT related to organizations for two different purposes. + +- Firstly, it can be used to assess the life cycle GHG emissions (first and second order effects) emerging from the use of ICT in non-ICT organizations, based on the Recommendation ITU-T L.1410. +- Secondly, it can be used as a supplement to [ISO 14064-1] and to [b-GHG Protocol] for ICT organizations intending to assess their own organizational energy consumption and GHG related impact. + +This Recommendation is intended to allow organizations to assess their direct GHG emissions (generally referred to as scope 1), their indirect GHG emissions (generally referred to as scope 2) and their other indirect GHG emissions (generally referred to as scope 3). It also allows organizations to assess their energy consumption by developing an energy inventory focusing on secondary energy used by the assessed organization itself. + +However, it should be noted that this Recommendation will not address: + +- GHG removal, which needs not be considered since ICT activities do not directly remove GHG, +- Other effects (apart from first or second order effects), such as rebound effects, since these effects are still under research to a large extent, +- Other environmental impacts like for example depletion of abiotic resources, acidification, eutrophication, stratospheric ozone depletion, photo-oxidant formation and human toxicity. + +## 1.1 Assessment of impact from the use of ICT in non-ICT organizations + +For the assessment of the first and second order effects when using ICT in non-ICT organizations, this Recommendation defines an assessment framework (principles, concepts, requirements and methods) to be used by any kind of organization (except for ICT organizations) when quantifying and reporting the energy consumption and the GHG emissions of ICT activities. + +## 1.2 Assessment of impact from ICT organizations + +For the assessment of an ICT organization, this Recommendation provides a methodology to assess both the energy consumption and the GHG emissions of its activities over a certain period of time for the following emissions: + +- direct GHG emissions +- energy indirect GHG emissions and +- other indirect GHG emissions. + +This Recommendation covers the following items: + +- design and development of the inventory +- components of the inventory +- quality management requirements of the inventory +- reporting of the inventory results. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T L.1400] Recommendation ITU-T L.1400 (2011), *Overview and general principles of methodologies for assessing the environmental impact of information and communication technologies*. + +[ITU-T L.1410] Recommendation ITU-T L.1410 (In-force), *Methodology for environmental impact assessment of information and communication technology goods, networks and services*. + +[ISO 14064-1] ISO 14064-1:2006, *Greenhouse gases – Part 1: Specification with guidance at the organization level for quantification and reporting of greenhouse gas emissions and removals*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 activity data** [b-GHG PI]: A quantitative measure of a level of activity that results in GHG emissions. Activity data is multiplied by an emission factor to derive the GHG emissions associated with a process or an operation. Examples of activity data include kilowatt-hours of electricity used, volume of fuel used, output of a process, hours a piece of equipment is operated, distance travelled and area of building. + +**3.1.2 emission factor** [b-PAS 2050]: Amount of greenhouse gases emitted, expressed as carbon dioxide equivalent and relative to a unit of activity (or example, kgCO2e per unit input). + +**3.1.3 facility** [ISO 14064-1]: Single installation, set of installations or production processes (stationary or mobile), which can be defined within a single geographical boundary, organizational unit or production process. + +**3.1.4 first order effect** [ITU-T L.1410]: The impacts and opportunities created by the physical existence of ICT and the processes involved, e.g., GHG emissions, e-waste, use of hazardous substances and use of scarce, non-renewable resources. + +**3.1.5 greenhouse gas** [ISO 14064-1]: Gaseous constituent of the atmosphere, both natural and anthropogenic, that absorbs and emits radiation at specific wavelengths within the spectrum of infrared radiation emitted by the Earth's surface, the atmosphere and clouds. Greenhouse gas include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6). + +**3.1.6 greenhouse gas emission** [ISO 14064-1]: Total mass of a Greenhouse gas released to the atmosphere over a specified period of time. + +**3.1.7 greenhouse gas removal** [ISO 14064-1]: Total mass of a Greenhouse gas removed from the atmosphere over a specified period of time. + +**3.1.8 ICT goods** [ITU-T L.1400]: The tangible products deriving from or making use of technologies devoted to or concerned with (a) the study and application of data and the processing thereof; *i.e.*, the automatic acquisition, storage, manipulation (including transformation), management, movement, control, display, switching, interchange, transmission or reception of a diversity of data; (b) the development and use of the hardware, software, and procedures associated with this delivery; and (c) the representation, transfer, interpretation, and processing of data among persons, places, and machines, noting that the meaning assigned to the data must be preserved during these operations. + +**3.1.9 ICT networks** [ITU-T L.1400]: This includes a set of nodes and links that provide physical or over the air information and communication connections between two or more defined points. + +**3.1.10 ICT services** [ITU-T L.1400]: This covers the combination of ICT goods and ICT networks. An ICT service is produced in one or more nodes of the network and provided to users or other ICT systems over the ICT network. + +**3.1.11 organization** [ISO 14064-1]: Company, corporation, firm, enterprise, authority or institution, or part or combination thereof, whether incorporated or not, public or private, that has its own functions and administration. + +**3.1.12 second order effect** [ITU-T L.1410]: The impacts and opportunities created by the ongoing use and application of ICT. This includes environmental load reduction effects which can be either actual or potential. + +**3.1.13 validation** [ISO 14064-1]: Systematic, independent and documented process for the assessment of a greenhouse gas assertion in a GHG project plan against agreed validation criteria. + +**3.1.14 verification criteria** [ISO 14064-1]: Policy, procedure or requirement used as a reference against which evidence is compared. Validation or verification criteria may be established by governments, GHG programmes, voluntary reporting initiatives, standards or good practice guidance. + +## **3.2 Terms defined in this Recommendation** + +This Recommendation defines the following terms: + +**3.2.1 direct GHG emissions** [b-GHG PI]: GHG emissions from GHG sources owned or controlled by the organization. + +NOTE – This term is referred to as "scope 1 emissions" in [b-GHG PI]. + +**3.2.2 energy indirect GHG emissions** [b-GHG Protocol Initiative]: Energy indirect GHG emissions cover GHG emissions from the generation of purchased energy, heat or steam consumed by the organization. Purchased electricity, heat or steam is defined as electricity, heat or steam that is purchased or otherwise brought into the organizational boundary of the company from external source. + +NOTE – This term is referred to as "scope 2 emissions" in [b-GHG PI]. + +**3.2.3 equity share**: An equity share is defined as the percentage of economic interest in, or benefit derived from a facility. + +**3.2.4 ICT activities**: ICT activities are defined as activities directly related to the design, production, promotion, sales or maintenance of ICT goods, networks or services, or related to the use of ICT goods, networks or services for the benefit of the organization. + +**3.2.5 ICT organization:** An ICT organization is an organization, the core activity of which is directly related to the design, production, promotion, sales or maintenance of ICT goods, networks or services. + +**3.2.6 operational control:** An organization has operational control if it has the full authority to introduce and implement its operating policies at the operation level. + +**3.2.7 other indirect GHG emissions [b-GHG PI]:** Other indirect GHG emissions cover GHG emissions, other than energy indirect GHG emissions, which are a consequence of an organization's activities but arise from GHG sources that are controlled by other organization. This term is referred to as scope 3 in [b-GHG Protocol]. + +NOTE – This term is referred to as "scope 3 emissions" in [b-GHG PI]. + +**3.2.8 primary energy:** Primary energy is the energy embodied in natural resources prior to undergoing any human-made conversions or transformations. + +**3.2.9 secondary energy:** Secondary energy is energy which has been refined from primary energy in an energy conversion process to a more convenient form of energy, such as electricity, refined or synthetic fuels (e.g., gasoline and hydrogen fuel). + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +CO2: Carbon Dioxide + +CO2e: CO2 equivalent + +EoLT: End-of-Life Treatment + +GHG: Greenhouse Gas + +GWP: Global Warming Potential + +ICT: Information and Communication Technology + +IPCC: Intergovernmental Panel on Climate Change + +kWh: kiloWatt-hours + +LCA: Life Cycle Assessment + +PC: Personal Computer + +# 5 Conventions + +None. + +# 6 Principles of organizational assessment + +The following principles shall be taken into consideration when carrying out the assessment. + +- Relevance +Select energy or GHG sources, data and methods appropriate to the assessment of the energy consumption or GHG emissions of ICT activities and organizations. +- Completeness +Include all specified energy sources or GHG emissions that provide a material contribution to the overall results. + +- **Consistency** +Enable meaningful comparisons of energy consumption or GHG emissions over time with respect to energy consumption, respectively GHG-related information of an organization. +- **Accuracy** +Reduce bias and uncertainties as far as practicable. +- **Transparency** +When communicating inventory results, the organization shall give sufficient information to support the interpretation of the results. + +# 7 Evaluation of energy consumption and GHG impact of ICT activities in non-ICT organizations + +The evaluation of the life cycle energy consumption and GHG impact of first and second order effects when using ICT in organizations should be based on [ITU-T L.1410] and aggregated to an organizational level according to the principles outlined in this Recommendation. + +It should be noted that the assessment of the second order effects needs to be documented and reported separately from the first order GHG emission impact. + +Clause 7 covers the use of ICT in any kind of organization, except for ICT organizations, including but not limited to organizations such as banks, insurance companies and public administrations. + +## 7.1 Use of the Recommendation ITU-T L.1410 to assess the impact from the use of ICT in organizations + +When assessing the impact of the use of ICT, the organization shall: + +- Identify the concerned ICT goods, networks or services of which the organization would like to assess the impact. +- Define operational boundaries for all these selected ICT goods, networks and services. +- If results from life cycle assessments (LCAs) are not available, perform an assessment of these product systems of ICT goods, networks and services in accordance with Part I of [ITU-T L.1410] in order to calculate the life cycle impact of these product systems. + +If the intention is also to capture the second order effects of the use of ICT goods, networks or services, a comparative assessment according to Part II of [ITU-T L.1410] needs also to be performed. + +## 7.2 Aggregation of impacts from ICT goods, networks and services at an organizational level + +When the selected product systems have been assessed as described above, the result needs to be aggregated to an organizational level. + +A simplified example could be given as follows: if the annual impact of a single PC is $x$ kg CO2e and the organization owns $n$ PCs, then the organizational impact of the PCs is $n \cdot x$ kg CO2e. This example is only applicable if the GHG emissions of the electricity mix (and other use conditions) are consistent for all the PCs within the scope of the assessment. + +Correspondingly, a simplified example for a service is as follows: if the actual or potential saving per meeting of utilizing a telepresence system instead of travelling is $y$ kg CO2e, and the company has saved $m$ meetings a year between the same destinations with $z$ travelling participants, the total savings at an organizational level becomes $y \cdot m \cdot z$ kg CO2e. + +In many cases, different operating conditions (e.g., energy supply emissions, lifetime usage, etc.) apply within the scope of the assessment and within organizations and shall then be taken into account. + +## **7.3 Organizational boundaries** + +The organizational boundaries shall be defined in accordance with clause 8. + +## **7.4 Operational boundaries** + +When assessing the impact of ICT in organizations the following aspects of an organization's operations shall be assessed with respect to their GHG emissions, in accordance with the principles outlined in clause 8: + +- ICT goods used by the organization. The ICT goods to be considered are further outlined in Annex A. +- Support equipment for ICT goods used by the organization (e.g., cooling and power supply equipment). +- ICT associated consumables used by the organization (e.g., ink cartridges, papers and DVDs). +- Software and ICT services used by the organization (e.g., purchased software, telecommunication services and consulting services). +- Staff responsible for purchase, operation and maintenance of ICT goods, networks and services. + +For each of these categories, which are detailed in clause 7.4.1, the GHG inventory shall include scope 1 and scope 2 GHG emissions, and it should also include scope 3 GHG emissions. + +Additionally, an energy inventory shall include direct energy consumption from sources described in clause 7.4.2. + +### **7.4.1 GHG Emissions** + +Defining the operational boundaries means identifying the emission sources that shall be included in the assessment. In order to help to define these boundaries, the following sources of emissions shall be identified when applicable: + +- Life cycle1 GHG emissions related to ICT goods used by the organization. The ICT goods to be considered are further outlined in Annex A. +- Life cycle GHG emissions related to support equipment for ICT goods used by the organization (e.g., cooling and power supply equipment). +- Life cycle GHG emissions related to ICT associated consumables used by the organization. Examples of such consumables include DVDs, paper and ink cartridges used for printing. +- Life cycle GHG emissions related to software and ICT services used by the organization (e.g., purchased software, telecommunication services and consulting services). The following activities may be considered: + - Software purchase and customization, + - Telecommunication services, + - ICT related consulting services. + +For staff responsible for purchase, operation and maintenance of ICT goods, networks and services the following activities may also be considered: + +--- + +1 Raw material acquisition, production (including design), use and end-of-life treatment + +- Daily commuting to work and business travel +- Freight of purchased ICT goods entering the organization, freight of ICT goods within the organization premises and freight of ICT goods leaving the organization's premises when decommissioned. + +For each of the three scopes (direct emissions, indirect emissions and other indirect emissions), the selected emission sources shall be clearly described and documented. + +### **7.4.2 Energy Consumption** + +Energy consumption from the following sources should be taken into account: + +- Energy consumption of ICT goods used by the organization: + - The ICT goods to be considered is further outlined in Annex A. Other ICT goods may also be considered as far as energy consumption is concerned. +- Energy consumption of support equipment for ICT goods used by the organization (e.g., cooling and power supply equipment): + - Energy consumption for power supply and power supply back-up systems for ICT goods; + - Energy consumption for power supply and power supply back-up systems dedicated to cooling of ICT goods; + - Electricity consumption for cooling of ICT goods. +- Energy consumption for staff responsible for purchase, operation and maintenance of ICT goods, networks and services: + - Energy consumption in the buildings hosting the ICT department's staff; + - Energy consumption for cooling and heating of the buildings hosting the ICT department's staff. + +The organization shall ensure that no double accounting occurs, for example between the energy consumed by cooling systems for ICT goods on one hand, and the energy consumed when cooling the building hosting the ICT department on the other hand. + +Annex A further outlines the list of goods that should be considered when assessing the direct energy consumption of an organization. Other ICT goods may also be considered as far as energy consumption is concerned. + +A list of selected goods shall be reported. + +# **8 Evaluation of energy consumption and GHG impact of ICT organizations** + +## **8.1 General** + +This clause provides ICT organizations with a means to evaluate its energy consumption and/or its GHG emissions. This GHG impact assessment shall follow [ISO 14064-1] for GHG emissions, and shall include scope 1 GHG emissions, scope 2 GHG emissions and should also include scope 3 GHG emissions. The methodology described in the chapter below gives more details on aspects specific to the ICT industry. + +## **8.2 Energy and GHG inventory design and development** + +In this Recommendation, the energy inventory is focusing on direct energy use by organizations in terms of secondary energy. + +### **8.2.1 Organizational boundaries** + +The organizational boundaries define which parts of the organization to include in the energy consumption or emissions assessment (e.g., main units, subsidiaries, joint ventures, etc.). + +The ICT organizations shall select a consolidation approach in accordance with [ISO 14064-1]. + +Irrespective of the approach chosen, ICT organizations should take into account all facilities used for the operation of the organization, whether owned or rented. + +The same consolidation approach shall be applied throughout the organizational boundaries. + +If the organization decides to exclude a particular facility or facilities, then this decision shall be justified. + +### **8.2.2 Operational boundaries** + +To determine if an activity contributes to the energy consumption and to scopes 1, 2 and 3 GHG emissions, the organization shall refer to the chosen approach used when setting its organizational boundaries. + +Within the organizational boundaries defined according to the approach chosen, emissions associated with all operational aspects shall be considered for scopes 1 and 2 GHG emissions and energy consumption. The operational impact generated by activities outside these boundaries is categorized as scope 3 and is further outlined in clause 8.3.5.1.3 and Appendix I. + +All identified emission sources should be described and reported. In case of third party reporting, the reporting is not required to be detailed in a way that leads to conflicts with confidentiality obligations. + +## **8.3 Quantification of energy consumption and GHG emissions** + +### **8.3.1 Quantification steps and exclusions** + +Within its organizational boundaries, according to [ISO 14064-1], the organization shall quantify and document energy consumption and GHG emissions by completing, as applicable, the following steps: + +- identification of energy consumption and GHG sources (8.3.2) +- selection of quantification methodology (8.3.3) +- calculation of energy consumption and GHG emissions (8.3.4). + +While keeping the five principles of organizational assessment (clause 6) in mind, the organization may exclude quantification of direct or indirect GHG sources or energy consumption if the assessment is not technically or economically feasible. The organization shall justify why certain GHG sources or energy consumption are excluded from quantification. + +### **8.3.2 Identification of energy consumption and GHG sources** + +The organization shall identify and record sources of energy consumption such as: + +- purchased electricity, heat or steam consumed by the organization +- fossil fuels consumed within the boundaries selected by the organization, by fixed or mobile equipment owned by the organization (e.g., a fuel-based power generator or a car owned by the organization) + +The organization shall identify and should record separately, for its internal use, GHG sources contributing to its scope 1 GHG emissions. + +The organization shall identify and should record separately, for its internal use, GHG sources contributing to its scope 2 GHG emissions. + +The organization should identify and record separately, for its internal use, GHG sources contributing to its scope 3 GHG emissions. + +The level of details for which energy consumption sources and GHG sources are identified and categorized should be consistent with the quantification methodology used. + +### **8.3.3 Selection of quantification methodologies** + +The organization shall use quantification methodologies described in this Recommendation, which are intended to minimize uncertainty and yield accurate, consistent and reproducible results. + +Estimation methods shall be documented. + +### **8.3.4 Calculation of energy consumption and GHG emissions** + +The energy consumption and GHG emissions shall be calculated in accordance with the quantification methodology described below. + +The detail of calculation procedures shall be documented. + +#### **8.3.4.1 Energy** + +The following requirements regarding energy consumption apply for the energy inventory: + +- energy from renewable sources produced within the organization's boundaries +- energy imported by the organization for its own consumption +- heat or steam imported by the organization for its own consumption +- fossil fuel (e.g., coal, gas or oil) consumed by fixed equipment owned by the organization +- fossil fuel (e.g., coal, gas or oil) consumed by mobile equipment (e.g., automobiles) owned by the organization + +The yearly energy consumption values shall be based on one of: + +- actual energy consumption indicated in invoices from electricity suppliers +- actual energy consumption measurements +- estimates based on actual energy consumption measured in selected representative sites and scaled up to represent all sites. Estimation methods shall be documented +- estimated mean value of energy consumption over one year multiplied by the number of applicable goods. Estimation methods shall be documented. + +For some categories of ICT goods, energy consumption over one year may be assessed using an estimated mean value of energy consumption over one year for a designated category of good, multiplied by the number of goods of the category. + +The total energy consumption per type of energy shall be calculated by summing the energy consumption of each entity within the selected boundaries. + +Energy consumption shall be assessed in kWh. + +The calculation details should be recorded for internal reference or reviewing by authorized persons. + +#### **8.3.4.2 GHG emissions** + +Since direct measurements of GHG emissions are generally not applicable for ICT organizations, most emission data are based on (measured or estimated) activity data (such as amount of electricity and fuel used) which are recalculated into CO2e (i.e. the equivalent quantity of CO2 that would be needed to give the same greenhouse gas effect as the corresponding amount of CO2). + +The recalculation from activity data into CO2e includes two steps: + +- First the activity data is recalculated into GHG emissions using CO2 and other GHG related emission factors for the applicable amounts of fuels, electricity or energy. Such emission factors can either be calculated by the organization or be collected externally from verified sources. +- Secondly the calculated amount of GHG emissions is recalculated into CO2e using the most recent Global Warming Potential (GWP) factors for the different greenhouse gases, as defined by the IPCC (see [b-IPCC]), taking into account a timeframe of 100 years. + +Note that for some fuels combined factors exist that combine both these recalculations into one step. For example an energy emission factor for a certain fuel can give the kg CO2e per unit of fuel, comprising the combined effect of the CO2, CH4 and N2O. In this case, the second step is not necessary. This is in contrast to the emission factor for global average electricity production with the unit of kg CO2/kWh which only takes the CO2-emissions and no other GHG emissions into account. + +The organization shall select or develop emission factors that + +- are derived from a recognized origin, +- are appropriate for the GHG source concerned, +- are valid at the time of quantification, +- take into account the quantification uncertainty and are calculated in a manner intended to yield accurate and reproducible results, and +- are consistent with the intended use of the GHG inventory. + +The organization shall explain its selection or development of GHG emission factors, including the identification of their origin and appropriateness for the intended use for the GHG inventory. + +The total organizational amount of CO2e is then calculated as the total sum of applicable amounts of CO2e relating to the considered year. + +The electricity and energy mixes applied (e.g., specific; national; global) shall be described. + +The calculation details should be recorded for internal reference and potential reviewing. + +Additionally, for scope 3 GHG emissions, life cycle impact is applicable for several categories (e.g., for purchased goods and services and for capital goods). For such categories, it should be noted that all life cycle stages except the use stage should be divided by the operational life time to get the yearly impact. For further details on operational life time refer to [ITU-T L.1410]. + +The table below gives examples of activity data for scope 3 GHG emissions. + +| Activities causing scope 3 GHG emissions | Example of activity data
(before multiplication by emission factors which take into account the physical properties of goods) | +|----------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +|
  • • ICT goods
  • • Consumables
  • • Disposal of ICT good
|
  • • Number of goods
  • • Volume and type of paper, number and type of ink cartridges
  • • Number and type of disposed ICT goods
| + +### 8.3.5 GHG inventory components + +#### 8.3.5.1 Identifying GHG sources + +##### 8.3.5.1.1 Direct GHG emissions (scope 1 GHG emissions) + +The organization shall quantify the direct GHG emissions generated by facilities within its organizational boundaries. + +Direct GHG emissions are principally the result of the following types of activities undertaken by the company: + +- Physical or chemical processing. Most of these emissions result from manufacture or processing of chemicals. It should be noted that this is applicable to ICT to a limited extent. +- Transportation of materials, products, waste and employees. These emissions result from the combustion of fuels in company owned/controlled mobile combustion sources. +- Fugitive emissions. These emissions result from intentional or unintentional releases such as sulfur hexafluoride (SF6), equipment leaks from joints, seals, packing, and gaskets during the use of refrigeration and air conditioning equipment, e.g., air conditioning for data centers and making wafers. +- Combustion of fuels e.g., for power supply back-up of ICT goods and cooling of ICT goods. + +##### **8.3.5.1.2 Energy indirect GHG emissions (scope 2 GHG emissions)** + +The organization shall quantify indirect GHG emissions from the generation of purchased electricity, heat, or steam consumed by the organization, within the selected organizational boundaries. For many organizations, purchased electricity represents one of the largest sources of GHG emissions and one of the most significant opportunities to reduce these emissions. + +Since ICT organizations in general are not energy producers, most emissions from internal operations will be reported in this category. Examples of operations using purchased energy thereby indirectly causing GHG emissions are heating and lighting of facilities, use of computers and use of other office goods. + +##### **8.3.5.1.3 Other indirect GHG emissions (scope 3 GHG emissions)** + +Scope 3 GHG emissions cover GHG emissions, additional to scope 2 GHG emissions, which are a consequence of an organization's activities but arise from GHG sources that are controlled by other organizations. + +If an organization chooses to assess scope 3 GHG emissions, the categories listed in Appendix I should be taken into account by the organization when claiming compliance with this Recommendation. + +Recognizing the complex and dynamic supply chain of ICT organizations, results from LCAs are seen as sufficiently accurate when assessing some scope 3 emissions (see Appendix I), and are recommended rather than an inventory based on input from all suppliers. + +LCAs related to ICT goods, networks and services used as input for the inventory of scope 3 GHG emissions should fulfill the requirements of [ITU-T L.1410]. In particular, the inventory should be based on data from representative (ICT specific) sources where applicable. + +The organization shall strive for the inventory to be relevant, complete, accurate, consistent and transparent, and shall apply these five principles in case of exclusion of activities. Any exclusion of activities made shall comply with the cut-off principles described in [ITU-T L.1410] which are applicable to all scope 3 categories. + +Goods, networks and services, as defined in [ITU-T L.1410], can be included as examples of indirect GHG emission sources. + +### **8.3.6 Organizational activities to reduce GHG emissions and energy consumption** + +Many organizations have initiatives to reduce GHG emissions, improve energy efficiency and/or increase GHG mitigation efforts. These activities may lead to a reduction in energy costs for an organization and/or lower the environmental impact and cost of GHG emissions. + +Therefore, organizations may identify existing ICT activities where optimizations could be envisaged with the objectives to reduce the GHG emissions and/or energy consumption. This Recommendation does not impose on the organization any requirement to disclose these potential improvements in its energy and GHG Report. + +Appendix II gives examples of actions that could be considered by the organization. + +## **8.4 Annual assessment** + +Organizations should track energy consumptions and GHG emissions on an annual basis in response to a variety of business goals such as public reporting, establishing GHG and energy consumption targets, managing risks and opportunities and addressing the needs of investors and other stakeholders. + +## **8.5 Establishment of base-year energy and GHG inventory** + +### **8.5.1 Selection and establishment of base year** + +As a principle, the publication date of this Recommendation (ITU base year) should be the base year for a GHG emission and energy consumption assessment. + +However, a different base year could be chosen when: + +- The organization estimates that the quantity and/or quality of available verifiable data for this particular different year would guarantee a more accurate evaluation of its GHG emissions and energy consumption. In this case, the organization should take all necessary measures in order to collect precise data and to apply this Recommendation not later than 2 years after the publication date. +- The organization has already put in place an assessment and reporting process based on a different base year, compliant with this Recommendation. In this case, the organization can continue to report from its initial base year. +- The activities carried out by the organization generate unusual fluctuations of GHG emissions and/or energy consumption in such a way that the base year might not be significant. In this case, the organization can choose an average of annual emissions and/or energy consumption over the 2 years prior the publication date. + +Any choice of a different base year shall be documented. + +### **8.5.2 Recalculation of energy or GHG inventory** + +Recalculation applies in two situations: + +- Structural changes which include mergers, acquisitions and divestments and/or outsourcing or in-sourcing of GHG emitting activities. +- Discovery of significant errors contained within the base year emission calculations which can necessitate a change in the emissions inventory. + +Structural changes shall be identified during the annual inventory reporting process via consultation with appropriate parts of the concerned organization. + +To ensure that data are consistent and historically relevant, it is considered reasonable that the base year emissions will not be recalculated when the following structural changes occur: + +- Acquisition of new facilities that did not exist in the base year. +- Organic growth or decline. + +Arithmetic and data entry mistakes can also occur in the recording and reporting of emissions data (e.g., incorrect conversion factors, wrong data reported from facilities, incorrect data entry into spreadsheets, incorrect spreadsheet formula calculations, etc.). Should errors be identified, corrections to the base year emissions shall be made. + +Similarly, should new data become available on source emissions that were not previously available (e.g., refrigerant loss records, etc.) or if a new methodology results in obtaining more accurate data on source emissions, an adjustment to the base year emissions may be required. + +## **8.6 Assessing and reducing uncertainty** + +An uncertainty assessment for GHG emissions shall be performed in accordance with clause 5.4 of [ISO 14064-1] to the extent needed to correctly interpret the inventory results. + +Uncertainty considerations for a GHG inventory which includes other indirect GHG emissions and value chain aspects is, to a large extent, the same as for an LCA and is further detailed in [ITU-T L.1410]. + +Consequently, the GHG inventory could be suitable for some purposes but less appropriate for others. + +The GHG inventory at an organizational level should primarily be used for the following purposes: + +- Identifying opportunities to improve environmental performance of the organization +- Providing information to decisions-makers in industry, government or non-government organizations about typical environmental performances of an organization to assist their policy choices +- Selecting relevant indicators for monitoring of environmental performance +- Understanding improvements in GHG emissions over time +- Aggregating GHG emissions to a sector level based on scopes 1 and 2 reporting, given that the same consolidation approach is applied. + +On the contrary the GHG inventory is not suitable for: + +- Comparisons of the environmental load between different organizations +- High accuracy aggregation of GHG emissions to a sector level2 based on scope 3 reporting. + +## **8.7 Energy and GHG inventory quality management** + +### **8.7.1 Energy and GHG information management** + +To ensure accurate reporting a sufficient level of data quality is required. Over time, all organizations should develop systems to track the preferred reporting units for all key emissions and, as part of the qualitative criteria, the appropriateness of the level of data that will be assessed. + +Data may be primary or secondary data. Primary data are process-specific data obtained by direct measurement of the energy or business activity. Secondary data are non-process specific data obtained from external sources other than direct measurement of the energy or business activity. For scopes 1 and 2 activity data, primary data applies. + +Activity data sources shall be identified and documented for internal purposes. + +--- + +2 The organizational GHG emission values may, however, be used for aggregations to a sector level if the intention is to get an indication of the magnitude of total GHG emissions. In case of aggregation, the double accounting effect needs to be avoided. + +### **8.7.2 Document retention and record keeping** + +Organizations are responsible for ensuring that a documentation plan is defined in sufficient detail so that the organization can track and record results, statements and conclusions given in the energy and GHG report or in any publicly available documents. + +A disclosure policy should be defined making a distinction between records used for internal purposes (e.g., organization staff or authorized persons) and records that could be reviewed by external parties. + +The organization is responsible for ensuring that data used to complete the energy and GHG Report or to support any publicly available documents be secured and accessible according to the disclosure policy. + +## **8.8 Reporting of energy and GHG inventory** + +### **8.8.1 General** + +This clause describes how the organization should prepare the GHG report to inform external and internal parties. + +Recommended options (denoted "should") in this Recommendation that are not taken into account shall be documented and justified. + +### **8.8.2 Planning the energy and GHG inventory report** + +The organization shall consider the following when planning and preparing its energy and GHG report: + +- Purpose and objectives of the report +- Intended use and users of the report +- Overall and specific responsibilities for preparing the report +- Frequency of the report +- Period for which the report is valid +- Report format +- Data and information to be included in the report +- Policy on availability and methods for dissemination of the report + +### **8.8.3 Energy and GHG report content** + +The energy and GHG report content should contain: + +- a description of the reporting organization and the person responsible +- the reporting period or periods covered +- documentation of organizational boundaries +- documentation of operational boundaries +- a description of the quantification methodologies used within the framework of the study +- the principles for collection of energy data, GHG activity data and emission factors +- the outcome of the uncertainty assessment for energy consumption and GHG emissions +Uncertainty assessment of for GHG emissions is further detailed in [ISO 14064-1]. +- the results of energy consumption assessment and GHG emissions assessment +- any recalculations including corrections of the corresponding clauses of the previous report(s) + +- a statement that the energy report and the GHG inventory report has been prepared in accordance with the principles outlined in the Recommendation. + +For the above items, at a minimum, guidance presented in Annex B shall be followed. + +Moreover, the following information shall be recorded by the organization for its internal use or to demonstrate compliance to the Recommendation to a reviewer: + +- Facilities taken into account. Any omission of facilities falling within the organizational boundaries shall be documented and justified. +- Number of people working in each facility +- Geographical location +- A general description of the use of the building +- Activity data per facility + +It should be noted that no reporting obligation applies for the above organizational details. + +### **8.8.4 Other indirect GHG emissions (Scope 3 GHG emissions)** + +For scope 3 GHG emissions the following reporting structure applies (references given below refer to the table in Appendix I): + +- Supply chain which consists of + - Purchased goods and services (S3A) + - Capital Goods (S3B) + - Upstream leased assets (S3H) + - Fuel- and energy-related activities not included in scope 1 or 2 (S3C) + - Upstream transportation and distribution (S3D) – all inbound +- Own activities which consists of + - Downstream transportation and distribution (S3J) – all outbound + - Business travel (S3F) + - Employee commuting (S3G) + - Downstream leased assets (S3N) – others + - Franchises (S3O) +- Operation of products which consists of + - Processing of sold products (including goods, networks and services) (S3K) + - Use of sold products (including goods, networks and services) (S3L) + - Downstream leased assets (S3N) – products +- End-of-Life Treatment (EoLT) which consists of + - Waste generated in operation (S3E) + - EoLT of sold products (including goods, networks and services) (S3M) + +Investments (S3I) including partly owned organizations are not considered but should be reported by the legal unit itself. (If such investments were included in the reporting they should be allocated to "Own activities"). + +The categories (S3A-S3O) should be transparently described with respect to the emissions considered. However, it is not required to report the emissions values per category. + +If any GHG reporting program needs additional detail (e.g., to avoid double accounting), such requirements would be additional to those of this Recommendation. To prevent unnecessary + +additional administrative burdens, it is however recommended that designers of such programs consider the detail of this Recommendation as being sufficient. + +### **8.8.5 Aggregation of emissions between organizations** + +If reported emissions including scope 3 are intended to be used for aggregation purposes to indicate the total input at a sector level, it must be understood that such an aggregation cannot give an accurate estimate. Moreover, in the case of aggregation, precautions must be taken to avoid any double accounting effect within the sector, as scope 1 and 2 GHG emissions of one organization may be accounted for as scope 3 GHG emissions by another organization. + +As an example, the energy needed for manufacturing a server is accounted for as scope 2 GHG emissions by the manufacturer, at the same time contributing to the scope 3 GHG emissions from a service provider operating the server. + +In conclusion, the most accurate basis for aggregation at a sector level would be to take into account scope 1 and 2 emissions from each organization, while including also scope 3 would lead to a more complete understanding of each organization but lead to less accuracy for aggregations. + +In case of aggregation between sectors, the same situation applies to an even larger extent (e.g., transports of ICT goods from a manufacturer to a customer is seen as scope 3 GHG emission by the manufacturer, as part of scope 3 GHG emissions for purchased goods by the customer and as scope 2 GHG emissions by the transport company). + +# **9 Organization's role in verification activities** + +For verification activities clause 8 of [ISO 14064-1] applies. + +# Annex A + +## **List of goods to be considered when assessing the impact of ICT activities in organizations** + +(This annex forms an integral part of this Recommendation.) + +When emissions due to goods used by the organization are concerned, the emissions from the following types of goods may be considered. The following list is not exhaustive and shows typical examples: + +- Desktops; +- Laptops; +- Cathode Ray Tube (CRT) screens; +- Flat screens; +- Individual printers; +- Cables; +- Network printers and copiers; +- Servers, switches and routers; +- Fax machines; +- Scanners; +- Fixed phones; +- Mobile phones; +- Personal Digital Assistants (PDA) and tablets; +- Projectors; +- Videoconference installations; +- Televisions; +- Cooling systems for ICT goods; +- Other small ICT goods; +- Outsourced ICT goods, in particular outsourced datacenters; +- Power supply back-up generators. + +It should be noted that these generators systems have to be dedicated to the ICT goods in this list. Otherwise an allocation approach would need to be used if the generators system is used for more than the ICT goods. The same remark applies for the cooling systems for ICT goods mentioned above. + +# Annex B + +## Information to be provided in the GHG emission and energy report on scope 1 and scope 2 GHG emissions and energy consumption + +(This annex forms an integral part of this Recommendation.) + +### - **Organizational boundaries** + +The organization should present a high-level description of facilities which have been taken into account and fall within the organizational reporting boundaries. + +### - **Operational boundaries** + +The organization shall present for each reporting year, a description of the energy and/or GHG emission sources included. + +The organization shall present in the Report, for each reporting year, any sources (e.g., facilities, activities, countries, etc.) of scope 1 and scope 2 GHG emissions which are not included in the Report and a justification for these exclusions. + +The organization shall present for each reporting year, a qualitative uncertainty statement regarding the total global scopes 1 and 2 GHG emissions figures supplied by the organization with a description of the sources of uncertainties. + +### - **Base year** + +The organization shall indicate in the report the base year chosen. If this is not the ITU base year, the organization shall provide justification for the different choice. + +### - **Reporting year** + +The organization shall indicate the reporting year(s) chosen. + +### - **Quantification methodologies, principles to collect data and emission factors** + +The organization shall provide for each reporting year, a list of the CO2 and CO2e emission factors used and their origin. + +For GWP factors, the applicable version of [b-IPCC] shall be stated. + +### - **Results of the energy and GHG assessments** + +The organization shall list for each reporting year, the countries where the organization operates and for which the organization is providing results of the energy and/or GHG assessments (main countries only, others can be grouped under "Rest of the World" (RoW)). + +The organization shall present for each reporting year its global scope 1 and 2 GHG emissions figures. + +The organization shall present for each reporting year its scope 1 and 2 GHG emissions breakdown per countries (main countries, RoW). + +The organization shall provide for each reporting year, a high-level update of its structure and a list of calculation errors with an analysis of their effects on the previous reports. + +### - **Recalculation** + +The organization shall indicate possible recalculations and include corrections of relevant sections of previous report(s). + +### - **Statement of compliance** + +The organization shall mention in the report a statement indicating that the organization provides this report in accordance with the most up-to-date version of this ITU-T Recommendation. + +# Appendix I + +## Indirect GHG emissions categories + +(This appendix does not form an integral part of this Recommendation.) + +This table is based on [b-GHG PI] and [b- GHG PI3]. + +| | Category | ICT application | Comments | +|-----------------|------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| S3A
(Note 1) | Purchased goods and services |
  • • Production-related procurement cradle-to-gate
  • • Non-production related procurement:
    Paper usage cradle-to-gate
    Use of hotels
  • • Related fuel and energy supply chain
Optional
  • • Other non-production related procurement of goods and services (Note 2)
  • • Manufacturing of vehicles, facilities and infrastructure
  • • Manufacturing of office equipment
  • • Product take-back services for sold products (as a purchased service not handled by the organization itself)
| Based on LCA (Note 3) | +| S3B | Capital Goods |
  • • Computer-ware cradle-to-gate (Notes 4,5)
  • • Related fuel and energy supply chain
Optional:
  • • Machinery (Note 6) production
  • • Cradle-to-gate emissions from vehicles, facilities and infrastructure
| Based on LCA | +| S3C | Fuel- and energy related activities not included in scope 1 or 2 |
  • • Fuel supply chain (Note 7) including transports. Infrastructure when data becomes available (Note 8) for fuel consumed by the reporting company
  • • Energy supply chain including transports. Infrastructure when data becomes available (Note 9) for energy consumed by the reporting company
|

The whole supply chain has to be taken into account for electricity including infrastructure, land use; diffuse emissions of methane from oil and coal extraction; SF6 from transformer stations and handling of waste from electricity production

Based on LCA. Electricity is of high importance for ICT industry.

The fuel supply chain is also of great importance for other forms of energy (e.g., district heating) and for fuels consumed (incinerated) at sites.

| + +| | Category | ICT application | Comments | +|-----|--------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| S3D | Upstream transportation and distribution |
  • Transports of products purchased by the organization (Note 10) (from supplier to the organization; between organization's facilities; to customer if paid by the organization)
  • Transports purchased by the organization
  • Related fuel supply chain
Optional:
  • Manufacturing of vehicles, facilities and infrastructure
  • Storage during distribution
  • Consultants (Note 11) working outside facilities used by the organization
| | +| S3E | Waste generated in operation | Optional:
  • Scope 1 and 2 emissions waste generated in operation that occur during disposal or treatment
| Considered to be of low significance for ICT and does also have a high uncertainty | +| S3F | Business travel |
  • Air, road, rail and boat travel
  • Related Fuel supply chain
Optional:
  • Manufacturing of vehicles, facilities and infrastructure
| Over time the effects of teleworking are likely to affect these emissions and also results for employee commuting and other energy indirect GHG emissions (Note 12). | +| S3G | Employee commuting |
  • Air, road, rail and boat travel including public transports
  • Related fuel supply chain
Optional:
  • Manufacturing of vehicles, facilities and infrastructure
| Based on behavior statistics
Over time the effects of teleworking are likely to affect these emissions and also results for employee commuting and other energy and/or indirect GHG emissions (Note 13). | +| S3H | Upstream leased assets |
  • Computer-ware cradle-to-gate (Notes 14,15)
  • Related fuel and energy supply chain
Optional
  • Leased cars (Note 16)
  • Manufacturing of office equipment
  • Manufacturing of vehicles, facilities and infrastructure
| | +| S3J | Downstream transportation and distribution |
  • Outbound transports ordered by the customer (Note 17)
  • Related fuel supply chain
Optional:
  • Manufacturing of vehicles, facilities and infrastructure
| | +| S3K | Processing of sold intermediate products |
  • Scope 1 and 2 during processing
| | + +| | Category | ICT application | Comments | +|-----|--------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------| +| S3L | Use of sold products |
  • Scopes 1 and 2 of use
  • Scopes 1 and 2 impact from use of support equipment necessary to operate the equipment (power supply and cooling)
  • Related fuel and energy supply chain
Optional:
  • Support activities (indirect use phase emissions) including repair, servicing and maintenance of sold products
| | +| S3M | EoLT of sold products |
  • Own disposal/treatment
  • Related fuel and energy supply chain
Optional (due to uncertainty)
  • Scopes 1 and 2 during disposal/treatment
| Based on LCA | +| S3N | Downstream leased assets |
  • Scopes 1 and 2 during operation
  • Related fuel and energy supply chain
Optional
  • Manufacturing and construction
| | +| S3O | Franchises |
  • Scopes 1 and 2 during operation
  • Related fuel and energy supply chain
Optional:
  • Manufacturing and construction
| | +| S3I | Investments | Optional:
  • Partially owned companies
| Recommended that the legal unit reports its own emissions to avoid double accounting | + +NOTE 1 – Also, goods and networks, as defined in [ITU-T L.1410], are examples of indirect GHG emission sources + +NOTE 2 – Services, e.g., finance, marketing, consultants and data traffic, could potentially be of interest for further studies in the future, but for the time being very little input data are available as a basis for inventories. + +NOTE 3 – See 8.3.5.1.3 + +NOTE 4 – Use of PCs accounted for as "energy indirect GHG emissions" + +NOTE 5 – Computerware includes PCs, servers, printers and copy machines etc. May in some organizations be part of leased assets + +NOTE 6 – Machinery for production, development, test and repair + +NOTE 7 – Lack of LCA data for district heating notified + +NOTE 8 – Lack of data so far + +NOTE 9 – Lack of data so far + +NOTE 10 – It is assumed that other Scope 3 (e.g., S3A, S3B) emissions contain their own transports + +NOTE 11 – Consultants located in the organization facilities should be accounted for as employees for practical reasons + +NOTE 12 – Energy use in visited organization neglected due to methodological problems/ uncertainty in data + +NOTE 13 – Energy use in visited organization neglected due to methodological problems/ uncertainty in data + +NOTE 14 – Use of PCs accounted for as scope 2 GHG emissions + +NOTE 15 – May in some organizations be part of Capital goods + +NOTE 16 – Not recommended for inclusion because already included in commuting/business travels + +NOTE 17 – It is assumed that other Scope 3 emissions contain their own transports + +# Appendix II + +## Examples of organizational activities to reduce GHG emissions and energy consumption + +(This appendix does not form an integral part of this Recommendation.) + +The following activities and initiatives are examples of energy consumption savings and GHG emissions reductions by enabling ICT solutions + +### - **Web-based service** + +Many organizations use web sites for different kinds of services. People can download documents from the web sites at home using their PC or laptop at any time. Using web-based services, people can save the time taken to visit the organization. Hence, paper can be saved as well as GHG emissions can be avoided by not commuting to the organization. + +### - **Smart-Work including teleconferencing** + +As a result of the distribution of high speed networks, many people choose to do smart-working using a smartphone, teleconferencing, etc. Especially, teleconferencing is beneficial to remotely located offices spread across the world. + +### - **Energy-efficient office machine** + +Organizations use energy-efficient office machines such as fax machines, printers, etc. to reduce energy consumption and therefore GHG emissions. Moreover, organizations use energy-efficient lamps to reduce energy consumption. The energy-efficient lamp has a motion sensor and brightness sensor so that the lamp can be turned off, dimmed, brightened, etc. in response to human motion and the brightness required. Organizations can also turn off the lamp during lunch time and after work to reduce energy consumption and GHG emissions. + +### - **Green data centres** + +Many organizations try to build green data centres to reduce GHG emissions and energy consumption. Data centres can consume large amounts of energy, so green technology is very important. [b-ITU-T L.1300] includes guidance on energy efficiency of data centres. + +### - **Building Energy Management System (BEMS)** + +Organizations adapt BEMS by connecting electricity, gas, water supply, heating and cooling systems to a management system to save energy. The BEMS collects building information such as energy consumption. + +### Emerging Applications + +### - **Education** + +Tele-education is an area that could grow rapidly, either as a substitute for traditional education or as a complement to it. It could improve the quality of learning in more specialized and advanced subjects. For equity as well as innovation, solutions could be provided that allow children living in rural areas to have the same quality of education as children in urban areas. + +### - **Health care** + +One important area for an aging population is the use of different kinds of telemedicine and remote assistance services. Safety and health will always be the first priority in health care but by providing new ICT based infrastructures, new solutions will be possible once people get accustomed to the new technology. + +By reducing the need to travel and overcoming the reluctance of many to go to the doctor, telemedicine could open up doors to preventive care that could reduce unnecessary suffering and waste of resources. This could also help to reduce the inequity in access to care between urban and rural areas. + +## Bibliography + +- [b-ITU-T L.1300] Recommendation ITU-T L.1300 (2011), *Best practices for green data centers*. +- [b-GHG PI] *A Corporate Accounting and Reporting Standard – Revised Version (2004)*, GHG Protocol Initiative. <[http://pdf.wri.org/ghg\\_protocol\\_2004.pdf](http://pdf.wri.org/ghg_protocol_2004.pdf)> +- [b-GHG PI3] *GHG Protocol Corporate Value Chain (Scope 3) Accounting and Reporting Standard(2011)*, GHG Protocol Initiative. +<[http://www.ghgprotocol.org/files/ghgp/Corporate%20Value%20Chain%20\(Scope%203\)%20Accounting%20and%20Reporting%20Standard.pdf](http://www.ghgprotocol.org/files/ghgp/Corporate%20Value%20Chain%20(Scope%203)%20Accounting%20and%20Reporting%20Standard.pdf)> +- [b-IPCC] *IPCC Guidelines for National Greenhouse Gas Inventories (in-force)*, Institute for Global Environmental Strategies. <> +- [b-PAS 2050] PAS 2050, *Specification for the assessment of the life cycle greenhouse gas emissions of goods and services (2011)*, British Standard Institute. +- [b-UNFCCC] United Nations Framework Convention on Climate Change (UNFCCC) website. <> + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git 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b/marked/L/T-REC-L.1481-202212-I_PDF-E/raw.md @@ -0,0 +1,317 @@ + + +# Recommendation **ITU-T L.1481 (12/2022)** + +SERIES L: Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant + +Assessment methodologies of ICTs and CO2 trajectories + +--- + +**Guidance on how to address the Connect 2030 targets on net greenhouse gas abatement** + +![ITU logo](0538daaa5583c23e17db3a12f2281a55_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features the letters "ITU" in a bold, blue, sans-serif font, superimposed on a stylized globe icon with intersecting lines. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +## ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT + +| | | +|-------------------------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node elements (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000–L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200–L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300–L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400–L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500–L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600–L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700–L.1799 | + +For further details, please refer to the list of ITU-T Recommendations. + +# Recommendation ITU-T L.1481 + +# Guidance on how to address the Connect 2030 target on net greenhouse gas abatement + +## Summary + +Recommendation ITU-T L.1481 provides guidelines on how to address the Connect 2030 target on net telecommunication/ICT-enabled greenhouse gas (GHG) abatement. It is intended to be utilized by relevant stakeholders of the Connect 2030 ambitions, while considering the sustainable development goal (SDG) 13 and the objectives of the Paris Agreement and the Glasgow Climate Pact. + +It also presents examples of information and communication technology (ICT) solutions associated with a potential reduction of GHG emissions in other sectors. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.1481 | 2022-12-07 | 5 | 11.1002/1000/15031 | + +## Keywords + +Connect 2030, GHG emissions, Glasgow Climate Pact, ICT sector, Paris agreement, SDG 13 goal. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2023 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|-----|---------------------------------------------------------------------------------------------------------------------------------------------|---| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 3.1 | Terms defined elsewhere ..... | 2 | +| 3.2 | Terms defined in this Recommendation ..... | 2 | +| 4 | Abbreviations and acronyms ..... | 2 | +| 5 | Conventions ..... | 2 | +| 6 | Principles..... | 3 | +| 7 | Challenges in quantifying the net ICT GHG second order effect compared to a baseline..... | 3 | +| 8 | Way forward for quantification of net ICT GHG second order effects..... | 4 | +| 9 | A non-comprehensive list of ICT solution with potential positive second order effects to help reduce overall GHG emissions in society ..... | 4 | +| | Bibliography ..... | 6 | + +## Introduction + +The United Nations Framework Convention on Climate Change (UNFCCC), entered into force in 1994, with the ultimate objective to stabilize greenhouse gas concentrations at a level that would prevent dangerous anthropogenic interference with the climate system. Since then, the Parties to the Convention have been negotiating protocols and agreements in order to set objectives and implement actions aimed at reaching the Convention's objective. + +The UNFCCC provides access to data on national greenhouse gas (GHG) emissions and removals, both by countries that are Parties to the Climate Change Convention, and by various organizations that also collect, estimate and/or disseminate data on GHG emissions/removals. + +The Paris Agreement [b-UNFCCC PA], which entered into force on November 4, 2016, agreed to work to keep a global temperature rise in 2100 well below 2°C, or preferably below 1.5°C, compared to preindustrial levels. In 2021, the Paris Agreement was complemented by the Glasgow Climate Pact, aiming to turn the 2020s into a decade of climate action and support [b-UNFCCC GCP]. + +Moreover, the United Nations adopted, in September 2015, the 2030 Agenda for Sustainable Development, which came into force in January 2016. This Agenda is composed of 17 sustainable development goals (SDGs) with their corresponding targets. + +Particularly, SDG 13 aims to take urgent action to combat climate change and its impacts and UN calls for action by using a wide array of technological measures and changes in behaviour, to limit the increase in global mean temperature in line with the Paris Agreement. + +In 2018, the ITU Plenipotentiary Conference met in Dubai and agreed on (PP-18 Resolution 200, Rev. Dubai, 2018) and the ITU's Connect 2030 Agenda which is linked to the Strategic Plan of the Union for the period 2020-2023, ensuring that technology serves humanity and the planet. + +More specifically, ITU has defined Connect 2030 target 3.4 as follows: *"By 2023, net telecommunication/ICT-enabled Greenhouse Gas abatement should have increased by 30% compared to the 2015 baseline"*. Such effects are referred to as second order effects in [ITU-T L.1410]. + +ITU-T SG5 has developed several Recommendations tackling second order aspects such as [ITU-T L.1410] "Methodology for environmental life cycle assessments of information and communication technology goods, networks and services", [ITU-T L.1430] "Methodology for assessment of the environmental impact of information and communication technology greenhouse gas and energy projects", [ITU-T L.1440] "Methodology for environmental impact assessment of information and communication technologies at city level", and [ITU-T L.1451] "Methodology for assessing the aggregated positive sector-level impacts of ICT in other sectors", as well [ITU-T L.1480] "Enabling the Net Zero transition: Assessing how the use of ICT solutions impacts GHG emissions of other sectors". However, the scope of Connect 2030 is different and the present Recommendation aims to complement those by providing guidance on how to address target 3.4, which deals with aggregated second order effects. + +It is noted that deriving the net telecommunication GHG abatement compared to a 2015 baseline may not be feasible, since the data availability is low and especially as such baseline is lacking. There are also methodological challenges. Acknowledging this situation, the present Recommendation aims to propose a way forward towards a deeper understanding of ICT's second order effects. + +# Recommendation ITU-T L.1481 + +# Guidance on how to address the Connect 2030 target on net greenhouse gas abatement + +## 1 Scope + +This Recommendation provides guidelines on how to address the Connect 2030 sustainability target 3.4, which states: "By 2023, net telecommunication/ICT-enabled greenhouse gas abatement should have increased by 30% compared to the 2015 baseline". Such effects are referred to as second order effects in [ITU-T L.1410] and [ITU-T L.1480]. + +This Recommendation aims to complement [ITU-T L.1410] and [ITU-T L.1480] by providing guidance on how to address target 3.4, which deals with aggregated second order effects. + +Hence, this Recommendation aims to propose a way forward towards a deeper understanding of how to increase and quantify ICT's second order effects. + +This Recommendation is intended to be utilized by relevant stakeholders to address the Connect 2030 ambitions, while considering the SDG 13 goal and the objectives of the Paris Agreement. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T L.1410] Recommendation ITU-T L.1410 (2014), *Methodology for environmental life cycle assessments of information and communication technology goods, networks and services*. +- [ITU-T L.1430] Recommendation ITU-T L.1430 (2013), *Methodology for assessment of the environmental impact of information and communication technology greenhouse gas and energy projects*. +- [ITU-T L.1440] Recommendation ITU-T L.1440 (2015), *Methodology for environmental impact assessment of information and communication technologies at city level*. +- [ITU-T L.1450] Recommendation ITU-T L.1450 (2018), *Methodologies for the assessment of the environmental impact of the information and communication technology sector*. +- [ITU-T L.1451] Recommendation ITU-T L.1451 (2018), *Methodology for assessing the aggregated positive sector-level impacts of ICT in other sectors*. +- [ITU-T L.1470] Recommendation ITU-T L.1470 (2020), *Greenhouse gas emissions trajectories for the information and communication technology sector compatible with the UNFCCC Paris Agreement*. +- [ITU-T L.1480] Recommendation ITU-T L.1480 (2022), *Enabling the Net Zero transition: Assessing how the use of information and communication technology solutions impact greenhouse gas emissions of other sectors*. + +## 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 first order effect** [ITU-T L.1480]: Direct environmental effect associated with the physical existence of an ICT solution, i.e., the raw materials acquisition, production, use and end of life treatment stages, and generic processes supporting those including the use of energy and transportation. + +NOTE 1 – First order effects include GHG and other emissions, e-waste, use of hazardous substances and use of scarce, non-renewable resources. + +NOTE 2 – First order effects are sometimes referred to as environmental footprints. + +**3.1.2 higher order effect** [ITU-T L.1480]: The indirect effect (including but not limited to rebound effects) other than first and second order effects occurring through changes in consumption patterns, lifestyles and value systems. + +NOTE 1 – Rebound effects includes such as financial gains, savings in time and space and others. + +NOTE 2 – Higher order effects could be associated with both second and first order effects. + +NOTE 3 – This emerges from [ITU-T L.1480] and was amended from [ITU-T L.1410] where it is referred to as other effects, and is also referred to as third order effects in some academic literature. + +**3.1.3 second order effect** [ITU-T L.1480]: The indirect impact created by the use and application of ICT which includes changes of environmental load due to the use of ICT that could be positive or negative. + +NOTE – Second order effects can be either actual or potential. + +### 3.2 Terms defined in this Recommendation + +None. + +## 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +GHG Greenhouse Gas + +ICT Information and Communication Technology + +SDG Sustainable Development Goal + +## 5 Conventions + +In this Recommendation: + +The expressions "is required" and "shall" indicate a requirement which must be strictly followed and from which no deviation is permitted if *full compliance* to this Recommendation is to be claimed. + +The expressions "is recommended" and "should" indicate a requirement which is recommended but which is not absolutely required. Thus, this requirement need not be present to claim compliance with this Recommendation. + +The expressions "can optionally" and "may" indicates an optional requirement which is permissible, without implying any sense of being recommended. This term is not intended to imply that the vendor's implementation must provide the option and the feature can be optionally enabled by the network operator/service provider. Rather, it means the vendor may optionally provide the feature and still claim conformance with this Recommendation. + +In all cases, the fundamental lifecycle assessment (LCA) principles of *relevance, completeness, consistency, accuracy and transparency* shall guide the practitioner. + +## 6 Principles + +The following principles shall be taken into consideration when estimating the lifecycle greenhouse gas (GHG) emissions of the information and communication technology (ICT) sector: + +- **relevance:** Select data and methods appropriate to the assessment. +- **completeness:** Include all elements that provide a material contribution to the overall results. +- **consistency:** Enable meaningful analysis regarding the development of results over time by using the same method and data sources. +- **accuracy:** Reduce bias and uncertainties as much as practicable. +- **transparency:** When communicating results, organizations shall give sufficient information to support the interpretation of the results. This means that data sources, data collection process as well as the modelling and the assumptions made must be clearly stated and motivated in the documentation, as well as all the boundaries and cut-offs. +- **conservativeness:** Conservative assumptions and values shall be used when there are uncertainties. Conservative quantification results will be underestimated rather than overestimated. + +## 7 Challenges in quantifying the net ICT GHG second order effect compared to a baseline + +ITU-T has developed several Recommendations tackling second order aspects such as + +- [ITU-T L.1410] "Methodology for environmental life cycle assessments of information and communication technology goods, networks and services" +- [ITU-T L.1430] "Methodology for assessment of the environmental impact of information and communication technology greenhouse gas and energy projects" +- [ITU-T L.1440] "Methodology for environmental impact assessment of information and communication technologies at city level" +- [ITU-T L.1451] "Methodology for assessing the aggregated positive sector-level impacts of ICT in other sectors" + +However, these Recommendations are not providing the guidance needed to address target 3.4. Moreover, there are limitations in availability of data and methodologies. However, ITU-T has recently developed [ITU-T L.1480] to provide the required guidance and to complement existing Recommendations by providing the necessary, more detailed, guidance on the assessment of second order and higher effects for various purposes, as well as other effects. This Recommendation will provide methodological guidance that could support the evaluation of Connect 2030 target 3.4. However, it is observed that such assessments are complicated and need substantial lead time and resources to be performed. + +With [ITU-T L.1480] there is sufficient methodological guidance in place to assess the effect of specific ICT solutions. However, it is noted that deriving the net telecommunication GHG abatement compared to a 2015 baseline, requires such a baseline to be established. This does not seem feasible, since it seems difficult to backtrack data for 2015. Especially, since this refers to data that ITU is not collecting on a regular basis, and data would need to be collected from various sources. + +With respect to data availability, keeping track of the current situation could also prove challenging, since, for the time being, there is a lack of published high quality data. + +A final challenge is the concept of "net abatement". ICT is a general-purpose technology, which means that its possible usages are very large. For this reason, it would not be possible to derive the total effect of ICT using micro- or meso-level methods (i.e., at the scale of users, organizations and communities). A more common approach would be to identify a selection of applications, derive their impact, and measure how it evolves over time. Capturing the overall enabling effect encompassing all solutions and effects is complicated and would demand the use of complementary macro level methodologies. + +## 8 Way forward for quantification of net ICT GHG second order effects + +Acknowledging the situation outlined in clause 7, this clause proposes a way forward towards a deeper understanding of ICT second order effects. + +ITU-T provides detailed guidance in [ITU-T L.1480], which will enable ITU to evaluate the contribution from selected ICT solutions for which data is available. For this reason, it is recommended that ITU should investigate how to contribute to the assessment of second order effects of ICT solutions by applying [ITU-T L.1480]. + +For future targets, there is an opportunity to monitor the development of the ICT sector itself based on the trajectories of [ITU-T L.1470], and the methodology for assessment of the ICT sector GHG emissions in [ITU-T L.1450]. ITU-T is also developing guidance on how to set up a database describing how data related to GHG emissions in the ICT sector could be collected and aggregated. + +Future targets could also refer to [ITU-T L.1480] combined with appropriate data collection and establishment of a baseline to keep track of the contribution from selected ICT solutions representative of the second order effects. Moreover, future targets could also consider the impacts on results from other effects, in particular rebound effects. + +## 9 A non-comprehensive list of ICT solution with potential positive second order effects to help reduce overall GHG emissions in society + +This clause gives a non-comprehensive list of ICT solutions, the use of which could potentially enable a reduction of GHG emissions. + +**Table 1 – Some ICT solutions that could help reduce GHG emissions** + +| Sector | Solution | Mechanism | +|----------------------------------------------|-------------------------------------------------------------------------|----------------------------------| +| Energy supply transformation and consumption | Improved metering and forecasting of electricity supply and demand | Optimization | +| | Optimization of grids, including load balancing through demand response | Optimization | +| | Improved energy system through demand side management | Optimization | +| Industry | As-a-service and sharing solutions | Optimization and/or substitution | +| | Circularity | Optimization | +| | Production efficiency | Optimization | +| Buildings | Intelligent building energy and resource management | Optimization | +| | Optimized use and sharing of buildings | Optimization and/or substitution | + +**Table 1 – Some ICT solutions that could help reduce GHG emissions** + +| Sector | Solution | Mechanism | +|--------------------------|--------------------------------|-----------------------------------------------------------------------------------------------------------| +| Transport | Virtual meetings | Substitution | +| | Remote work | Substitution | +| | Route optimization | Optimization | +| | Fleet management and logistics | Optimization | +| | Eco-driving | Optimization | +| | Shared mobility | Optimization and/or substitution | +| Agriculture and forestry | Precision agriculture | Optimization | +| | Precision forestry | Optimization | +| Nature-based sinks | Forest protection | Providing information and managing data, Facilitation, accessibility, affordability and rising motivation | + +## Bibliography + +- [b-ITU-T L.1400] Recommendation ITU-T L.1400 (2023), *Overview and general principles of methodologies for assessing the environmental impact of information and communication technologies*. +- [b-UNFCCC GCP] United Nations Framework Convention on Climate Change (2021). Glasgow Climate Pact. Glasgow: United Nations. 8 pp. Available [viewed 2023-02-16] at: +- [b-UNFCCC PA] United Nations Framework Convention on Climate Change (2015). Paris agreement. New York, NY: United Nations. 27 pp. Available [viewed 2023-02-16] at: [https://unfccc.int/sites/default/files/english\\_paris\\_agreement.pdf](https://unfccc.int/sites/default/files/english_paris_agreement.pdf) + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1490-202408-I_PDF-E/0538daaa5583c23e17db3a12f2281a55_img.jpg b/marked/L/T-REC-L.1490-202408-I_PDF-E/0538daaa5583c23e17db3a12f2281a55_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..f3e13e96dc5d12fda0a12c5bf8d7495c8d488e15 --- /dev/null +++ b/marked/L/T-REC-L.1490-202408-I_PDF-E/0538daaa5583c23e17db3a12f2281a55_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:8b96edad95329705d476c05b141b269b7825f6e55a4c6a90154d5ba50d7b6aac +size 7332 diff --git a/marked/L/T-REC-L.1490-202408-I_PDF-E/d4af765160d04ecef538e5066006dc77_img.jpg b/marked/L/T-REC-L.1490-202408-I_PDF-E/d4af765160d04ecef538e5066006dc77_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..1a44f934a3c5f0dce0f21823cbe5dbdb623afec8 --- /dev/null +++ b/marked/L/T-REC-L.1490-202408-I_PDF-E/d4af765160d04ecef538e5066006dc77_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:7f2765b277345303a2c966e376026571e69da229d3353d60804c14ca29afca3c +size 101627 diff --git a/marked/L/T-REC-L.1490-202408-I_PDF-E/ebff22fb5dd6f50a90e44dca0f82f285_img.jpg b/marked/L/T-REC-L.1490-202408-I_PDF-E/ebff22fb5dd6f50a90e44dca0f82f285_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..2e6e3af0001da203002ff5438180c9981378a6ae --- /dev/null +++ b/marked/L/T-REC-L.1490-202408-I_PDF-E/ebff22fb5dd6f50a90e44dca0f82f285_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:758b0df3f5ac0bb5330eb2146d8654c37decb265f2c80a0b15f032f06a6fc11c +size 109154 diff --git a/marked/L/T-REC-L.1490-202408-I_PDF-E/raw.md b/marked/L/T-REC-L.1490-202408-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..068d23aefe3c847974ee6b520f8b8588b68cd8c3 --- /dev/null +++ b/marked/L/T-REC-L.1490-202408-I_PDF-E/raw.md @@ -0,0 +1,464 @@ + + +# Recommendation **ITU-T L.1490 (08/2024)** + +SERIES L: Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant + +Assessment methodologies of ICTs and CO2 trajectories + +--- + +### **Framework and functional requirements of a greenhouse gas emissions management system using digital technology for the public sector** + +![ITU logo](0538daaa5583c23e17db3a12f2281a55_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue circular emblem with a stylized globe and the letters 'ITU' in white. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +### **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|--------------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| Infrastructure including node elements (except cables) | L.200-L.249 | +| General aspects and network design | L.250-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| Optical fibre cable maintenance | L.300-L.329 | +| Infrastructure maintenance | L.330-L.349 | +| Operation support and infrastructure management | L.350-L.379 | +| Disaster management | L.380-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1490 + +## Framework and functional requirements of a greenhouse gas emissions management system using digital technology for the public sector + +## Summary + +With the frequent occurrence of extreme climate events around the world, it has become a global consensus to deal with climate change, and countries have stepped up efforts to manage and control their greenhouse gas (GHG) emissions. The rapid development of information and communication technology (ICT) provides an effective tool for GHG management. By applying big data, cloud computing, and other ICT to build a greenhouse gas emissions management system (GHGEMS), the public sector can more accurately quantify, monitor and manage regional GHG emissions, thereby achieving data-driven decision support. Recommendation ITU-T L.1490 proposes a GHG emissions management using ICT for the public sector, and specifies the requirements for system construction principles, framework and functional requirements. + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.1490 | 2024-08-29 | 5 | 11.1002/1000/16000 | + +## Keywords + +GHG emissions management, ICT, public sector. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, and information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2024 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere..... | 1 | +| 3.2 Terms defined in this Recommendation ..... | 1 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 2 | +| 6 Design principles..... | 2 | +| 7 Framework requirements ..... | 2 | +| 7.1 Data acquisition layer ..... | 3 | +| 7.2 Infrastructure layer ..... | 3 | +| 7.3 Data management layer ..... | 4 | +| 7.4 Application layer ..... | 4 | +| 7.5 Presentation layer..... | 4 | +| 8 Functional requirements..... | 4 | +| 8.1 GHG emission accounting..... | 4 | +| 8.2 GHG emissions analysis ..... | 5 | +| 8.3 GHG emission estimation..... | 5 | +| 8.4 CFP management..... | 6 | +| 8.5 GHG emission early warning ..... | 6 | +| 8.6 Target assessment management..... | 7 | +| 8.7 Information issue ..... | 7 | +| 8.8 Public services ..... | 7 | +| Appendix I – LEAP model explanation ..... | 8 | +| Appendix II – KAYA model explanation ..... | 10 | +| Bibliography ..... | 11 | + + + +# Recommendation ITU-T L.1490 + +## Framework and functional requirements of a greenhouse gas emissions management system using digital technology for the public sector + +# 1 Scope + +This Recommendation describes the design principles, framework and functional requirements of the greenhouse gas emissions management system (GHGEMS), which applies to the design of a greenhouse gas emissions management system for the public sector. + +The scope of this Recommendation includes: + +- Design principles. +- Framework of a greenhouse gas emissions management system. +- Functional requirements. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +None. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 greenhouse gas (GHG)** [b-ITU-T L.1410]: GHG are the seven gases listed in the Tokyo Protocol: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6) and nitrogen trifluoride (NF3). + +**3.1.2 GHG emission** [b-ISO 14064-1]: Release of a greenhouse gas (GHG) into the atmosphere. + +**3.1.3 public sector** [b-ITU-T L.1061]: All levels of government and government-controlled or funded agencies, enterprises and other organizations that deliver public programmes, goods or services. + +**3.1.4 carbon footprint of a product (CFP)** [b-ISO 14067]: Sum of greenhouse gas (GHG) emissions and GHG removals in a product system, expressed as CO2 equivalents and based on a life cycle assessment using the single impact category of climate change. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following term: + +**3.2.1 greenhouse gas emissions management system (GHGEMS)**: A system for accounting, analysing, estimating, and managing of greenhouse gas (GHG) emissions. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|--------|--------------------------------------------| +| API | Application Programming Interface | +| CFP | Carbon Footprint of a Product | +| DB | Database | +| GDP | Gross Domestic Product | +| GHG | Greenhouse Gas | +| GHGEMS | Greenhouse Gas Emissions Management System | +| ICT | Information and Communication Technology | +| IoT | Internet of Things | +| VPN | Virtual Private Network | + +# **5 Conventions** + +None. + +# **6 Design principles** + +The construction principles of the greenhouse gas emissions management system (GHGEMS) include good practicability, flexibility and scalability, and simple operation. + +- Good practicability: the system should meet the basic needs of the public sector for accounting, analysis and management of greenhouse gas (GHG) emissions. +- Flexibility and scalability: the system should reserve interfaces and secondary development application programming interfaces (APIs) for new functions and new users that may be added in the future, and can continue to expand with the development of management needs. +- Simple operation: the interface of the system should be designed to be as simple as possible, and easy for users to understand and operate. + +# **7 Framework requirements** + +The framework of GHGEMS using information and communication technology (ICT) for the public sector includes five layers, which are the data acquisition layer, infrastructure layer, data management layer, application layer and presentation layer, as shown in Figure 1. + +![Figure 1 – Framework of the GHGEMS. The diagram shows five layers: Presentation layer (PC, Mobile terminals, .....), Application layer (GHG emission accounting, GHG emission analysis, GHG emission estimation, CFP management, GHG emission early warning, Target assessment management, Information issue, Public service), Data management layer (Accounting DB, Analysis DB, CFP DB, .....), Infrastructure layer (Server, Storage device, Network, Security device), and Data acquisition layer (IoT collection, System docking, Manual collection).](ebff22fb5dd6f50a90e44dca0f82f285_img.jpg) + +L.1490(24) + +Figure 1 – Framework of the GHGEMS. The diagram shows five layers: Presentation layer (PC, Mobile terminals, .....), Application layer (GHG emission accounting, GHG emission analysis, GHG emission estimation, CFP management, GHG emission early warning, Target assessment management, Information issue, Public service), Data management layer (Accounting DB, Analysis DB, CFP DB, .....), Infrastructure layer (Server, Storage device, Network, Security device), and Data acquisition layer (IoT collection, System docking, Manual collection). + +**Figure 1 – Framework of the GHGEMS** + +## 7.1 Data acquisition layer + +The data acquisition layer collects the data related to an account and analyses the GHG emissions. This layer is the data source of the GHGEMS and includes data acquisition hardware, network resources and other facilities, and provides the data basis for the data management layer. The collecting frequency of data depends on the importance of the data and their applications. The collecting methods mainly comprise Internet of things (IoT) collection, system docking and manual collection. Users can choose the collection method according to their own situation and management needs. The following describes the three collecting methods. + +### a) IoT collection + +Using this method data is actively uploaded to the GHGEMS through a wired or wireless communication network by deploying collection devices such as intelligent meters and IoT sensing devices. + +This collecting method can be used in cities which have ability to install IoT collection devices on a large scale. These cities may install IoT measurement devices (e.g., smart electricity meters and smart gas meters) to collect data for accounting of GHG emissions. IoT-based GHG emission monitoring devices can be installed on stationary GHG emission sources to regularly collect GHG emission data. + +### b) System docking + +This method can be considered if the city has implemented the digital management of energy, industry, transportation or agriculture through the establishment of a system. The GHGEMS can interface with other systems to collect data which can be used for GHG emissions accounting and analysis. + +This method needs to build external interfaces to connect data sources outside. The specific docking type is based on the type of information system data provided to the outside, and data push is preferred. If not supported, data can be collected from the system according to the management need. + +## 7.2 Infrastructure layer + +The infrastructure layer consists of servers, storage devices, network and security devices. It provides computing, storage, and network services to ensure a secure and stable operating environment for the GHGEMS. + +The server system needs to conform to the principle of standardization and open system interconnection, it needs to be easy to develop and maintain, but also have strong network communication, database management functions and strong extensible abilities. In the design of the server, it is best to use modular and common parts design. + +The storage devices should evolve storage demands. It is imperative to have reliable software and hardware devices in place to ensure data security and reliability. Simultaneously, these devices should exhibit exceptional performance characteristics such as good storage capacity, high-speed data transmission, rapid response time, and be energy-efficient and cost-effective. + +The network speed and throughput capacity should be ensured to meet the requirements of business development. The security of data transmission and storage needs to be guaranteed to prevent unauthorized access to the network system. Support for multiple protocols is necessary to enable integration with other networks. The network system should possess strong fault tolerance and fault recovery capabilities. + +The security devices comprise firewall, fortified host, network security audit system, vulnerability scanner, intrusion detection system, security authentication gateway, virtual private network (VPN) gateway, database security audit system, etc. Different types of security equipment do not utilize products from the same manufacturers. + +## **7.3 Data management layer** + +The data management layer extracts, cleans summarizes and stores the collected data. This layer supports both relational and non-relational databases. The recommended databases are as follows. + +- Accounting database stores and manages data related to regional GHG emissions accounting. The accounting database shall include low-order calorific value, carbon content per unit calorific value, fuel carbon oxidation rate and emission factor. +- Analysis database stores and manages data related to GHG emissions analysis. The database shall include energy consumption, GHG emissions, gross domestic product (GDP), population, etc. +- Carbon footprint of a product (CFP) database stores and manages data to calculate and analyse the CFP. The database shall include the name, brand, raw materials consumption, and energy consumption of the product. + +## **7.4 Application layer** + +The application layer provides the specific application of data resources. It shall include GHG emissions accounting, GHG emissions analysis, GHG emissions estimation, CFP management, GHG emissions early warning, target assessment management, information issues, and public services. These application services need to meet the public sector's requirements for GHG emissions display, accounting and analysis. + +## **7.5 Presentation layer** + +The presentation layer provides access entrances to users. The access methods shall at least include personal computer (PC) and intelligent mobile phone access. + +# **8 Functional requirements** + +## **8.1 GHG emission accounting** + +This function mainly includes GHG emission factors management, accounting formula management, GHG emission accounting and report generation. + +The GHG emission factor management function manages and modifies emission factors or default values. The system provides a preset default value for emission accounting and allows users to modify the default value. + +The accounting formula management function can edit and modify the GHG emissions accounting formula. + +The GHG accounting function allow users to select accounting boundaries and accounting methods, and automatically calculate GHG emissions through the input of activity data. + +The report generation function refers to the generation of GHG emissions reports based on accounting results. The reports can be provided in various formats such as Word, Excel, PDF, etc. + +## **8.2 GHG emissions analysis** + +This function provides users with GHG emissions statistics, analysis, comparison and display services. The system should analyse the amount, structure, intensity and other data of energy consumption and GHG emissions according to type and specific periods, and show them in charts and tables. + +The GHG emissions amount analysis refers to conducted statistics and analysis on the relevant total volume of GHG emissions in a city and shows the changing trend. At the same time, users can select a specific time range to compare and display regional GHG emissions (e.g., maximum, minimum, average values of GHG emissions). + +The structure analysis refers to analysis of GHG emissions based on different cities, GHG type and emission source. Additionally, it enables the visualization and retrieval of historical data changes. For instance, when analysing city GHG emissions, the system can utilize distinct colours to indicate GHG emissions in each district on a map. Similarly, the system can analyse the proportions and variations of different gases, as well as greenhouse gas emissions from different activities. + +The intensity analysis supports the system to analyse intensity indicators that reflect GHG emissions levels by combining basic data such as gross domestic product, and permanent population. The recommended intensity indicators are as follows: + +- GHG emissions per unit of GDP; +- per capita GHG emissions; +- GHG emissions per unit of energy consumption; +- energy consumption intensity. + +## **8.3 GHG emission estimation** + +The GHG emission estimation function allows for estimation of GHG emission over a time period and to identify key factors that influence the GHG emissions. Specifically, based on historical GHG emissions, population, GDP, energy consumption and other data, the system can estimate GHG emissions under different scenarios through the algorithm model (e.g., LEAP, KAYA). The process is shown in Figure 2. + +![Flowchart of the GHG emissions estimation function process, divided into three stages: Accounting, Modelling, and Estimation.](d4af765160d04ecef538e5066006dc77_img.jpg) + +``` + +graph TD + subgraph Accounting + A1[Select the base year] + A2[GHGs emission activity data input] + A3[GHGs emission accounting] + end + subgraph Modelling + M1[Identify the factors affecting GHGs emission] + M2[Establish GHGs emission estimation model] + M1 --- P1[Population] + M1 --- P2[Per capita GDP] + M1 --- P3[Energy intensity] + M1 --- P4[...] + M2 --- P5[LEAP] + M2 --- P6[KAYA] + M2 --- P7[...] + end + subgraph Estimation + E1[Parameter setting in different situations] + E2[GHGs emission estimation] + E1 --- P8[Baseline scenario] + E1 --- P9[Scenario 1] + E1 --- P10[Scenario 2] + E1 --- P11[...] + E2 --- P12[GHG emission per year] + E2 --- P13[GHG emission peak] + E2 --- P14[Time to GHG emission peak] + E2 --- P15[...] + end + A3 --> M1 + M2 --> E1 + +``` + +The diagram illustrates the GHG emissions estimation function process, organized into three horizontal stages: Accounting, Modelling, and Estimation. The Accounting stage includes three blue boxes: 'Select the base year', 'GHGs emission activity data input', and 'GHGs emission accounting'. An orange arrow points from 'GHGs emission accounting' to the Modelling stage. The Modelling stage contains two blue boxes: 'Identify the factors affecting GHGs emission' and 'Establish GHGs emission estimation model'. To the right of 'Identify the factors...' are four yellow boxes: 'Population', 'Per capita GDP', 'Energy intensity', and '...'. To the right of 'Establish GHGs emission estimation model' are three yellow boxes: 'LEAP', 'KAYA', and '...'. An orange arrow points from 'Establish GHGs emission estimation model' to the Estimation stage. The Estimation stage contains two blue boxes: 'Parameter setting in different situations' and 'GHGs emission estimation'. To the right of 'Parameter setting...' are four yellow boxes: 'Baseline scenario', 'Scenario 1', 'Scenario 2', and '...'. To the right of 'GHGs emission estimation' are four yellow boxes: 'GHG emission per year', 'GHG emission peak', 'Time to GHG emission peak', and '...'. + +L.1490(24) + +Flowchart of the GHG emissions estimation function process, divided into three stages: Accounting, Modelling, and Estimation. + +**Figure 2 – The GHG emissions estimation function process** + +NOTE – In Figure 2, low emissions analysis platform (LEAP) and KAYA are statistical models used to assess GHG emission trends over a specific time period. Appendix I and Appendix II will provide detailed explanations for these two statistical models. Other models are also available. + +## 8.4 CFP management + +The GHGEMS is recommended to provide the carbon footprint of a product (CFP) management function for government-controlled or funded agencies and enterprises. The CFP management function mainly includes CFP accounting and analysis. + +The CFP accounting function refers to quantifying of the carbon footprint of a product category. Specifically, users can define functional units, input activity data and select GHG emission factors to calculate CPF and GHG emissions of a product at various stages of a life cycle. + +The CFP analysis function may include structure analysis, time analysis, brand analysis, etc. Structure analysis refers to the analysis and comparison of key indicators such as the proportion and rate of change in CFP at each stage of a life cycle. Time analysis enables an assessment of the historical trend of the product carbon footprint. Brand analysis supports a comparative evaluation of the carbon footprints among similar products manufactured by different companies, including average, maximum, and minimum values. The results of these analyses can be presented in various formats such as tables, histograms, and trend charts. + +## 8.5 GHG emission early warning + +The greenhouse gas emission early warning function can analyse the abnormal fluctuations of GHG emissions according to energy consumption, production, etc., and provide timely warning of the possible excessive greenhouse gas emissions based on the early warning value set by the public sector. + +The system can set different warning levels and distinguish them by colour, such as red for the first level, orange for the second level, and yellow for the third level. The first level of early warning indicates that the GHG emission of the city has seriously exceeded the value, prompting users to pay special attention. The system supports intelligent pushing of GHG emission reduction suggestions to users according to the early warning information, and regularly tracks changes of the warning level. + +## **8.6 Target assessment management** + +This function enables competent authorities to issue assessment indicators, such as total GHG emissions and GHG emission intensity, to subordinate departments through the system, and realize regular tracking and management of assessment indicators. Target assessment management consists of three sub-functions: target management, target implementation and target assessment. + +The target management function supports the competent authorities to input and manage the assessment indicators of subordinate departments in the system. The assessment indicators can include annual total energy consumption, annual energy consumption intensity, annual total GHG emissions, annual GHG emission intensity, annual GHG emission reduction, etc. In addition, this function supports the creation, deletion, modification, review and query of assessment indicators. For example, the user can create and define assessment indicators, and specify the assessment level and assessment period through the system, so as to facilitate the management of assessment indicators by the competent authorities. + +The target implementation function supports data reporting and progress tracking of target achievement. Data reporting means subordinate departments can input required assessment data, such as GHG emissions, through the system. The system should also support manual approval and checking. If the checker finds errors in filling, they can be modified. The progress tracking of the target achievement function can display the progress of target achievement of each city in a variety of charts, so as to be convenient for the competent departments to track progress of target achievement. + +The assessment function supports users to analyse, compare and display the target and the actual completion. It also supports users to query the assessment results. + +## **8.7 Information issue** + +The information issue function enables the public sector to issue notification, announcements, news or other information through the system. In addition, the system supports the creation, deletion, modification and query of issued information. + +The information issue method is recommended to include public issues and specific scope issues. For public issues, everyone can access information through the system. For specific scope issues, the system allows users to select the object and content of information to be issued. + +## **8.8 Public services** + +Public service refers to the system that provides GHG emissions management services for private enterprises or agencies. Specifically, after logging in, private enterprises or agencies may carry out GHG emissions accounting at organization level or CFP accounting services provided by the system, and apply for product carbon footprint certification. At the same time, the system supports regular notification, announcements, and news to private enterprises or agencies to help them improve GHG emission management. + +## Appendix I + +### LEAP model explanation + +(This appendix does not form an integral part of this Recommendation.) + +The low emissions analysis platform (LEAP) model is a statistical model based on the scenario analysis and is widely applied in public sectors to measure, forecast and manage GHG emission. The LEAP model is based on following calculation formula: + +$$G = \sum_j \sum_i \sum_m A_{j,i} \times E_{j,i,m} \times F_m$$ + +In this formula, $G$ refers to the total GHG emission. $A$ refers to activity data about the energy consumption activities. $E$ is the energy intensity. $F$ refers to emission factors. $j$ refers to sectors which consume energy. $i$ refers to categories of energy consumption activities. $m$ refers to categories of energy. + +Using the LEAP model to forecast GHG emissions comprises three steps. This part will use an industrial sector as an example to explain this process [b-Feng] [b-Xu]: + +#### a) Establish foundation database + +This step needs to collect both socioeconomic data and data related to energy consumption. Socioeconomic data may include GDP, population, urbanisation rate, and so on. Data related to energy consumption may include activity level data, energy intensity data, energy structure data, and so on. + +#### b) Set scenario + +This step needs to set different scenarios to forecast GHG emissions in different scenarios. Three kinds of scenario can be set, including GDP-based scenarios, industrial development scenarios and GHG reduction scenarios. + +- 1) GDP-based scenario: Considers changes in GHG emissions under increasing GDP, falling GDP and a constant GDP scenario. +- 2) Industrial development scenario: Considers changes in GHG emissions under different situations of industrial development, including: + - Rapid industrial development + - Slow industrial development + - No development + - Slow industrial recession + - Rapid industrial recession +- 3) GHG reduction scenario: Considers changes in GHG emissions when different actions are taken to reduce GHG emissions, including three scenarios: + - Baseline scenario: Refers to the scenario which does not take any measures about energy saving and GHG reduction. + - GHG reduction scenario: Refers to the scenario which conducts macro-control, including limiting growth of high emissions industry and optimizing the structure of industrial development. + - Enhanced GHG reduction scenario: In addition to conducting macro-control, this scenario will also consider applications and the development of GHG reduction technologies (e.g., advanced energy storage technology). + +Based on different development levels, different public sectors may comprehensively consider GDP, industrial development and GHG reduction when they set scenarios, rather than only considering individual factors. + +#### c) GHG emission forecast + +Based on the LEAP model and calculation software, calculates and forecasts GHG emissions in the future. + +## Appendix II + +### KAYA model explanation + +(This appendix does not form an integral part of this Recommendation.) + +The KAYA model connects GHG emissions with energy structures, energy intensity, economic growth and population factors. The KAYA model is mainly based on following formula [b-Kaya]: + +$$G = \frac{G}{E} \times \frac{E}{GDP} \times \frac{GDP}{P} \times P$$ + +In this formula, $G$ refers to total GHG emissions. $E$ refers to energy consumption. $GDP$ is gross domestic product and $P$ is population. + +This formula presents that changes in GHG emissions have a relationship with GHG emissions per unit of energy consumption ( $\frac{G}{E}$ ), energy consumption per unit of GDP ( $\frac{E}{GDP}$ ), GDP per capita ( $\frac{GDP}{P}$ ) and population ( $P$ ). This means that public sectors can use these factors to forecast GHG emissions in the future [b-Kaya]. + +## Bibliography + +- [b-ITU-T L.1410] Recommendation ITU-T L.1410 (2014), *Methodology for environmental life cycle assessments of information and communication technology goods, networks and services.* +- [b-ISO 14064-1] ISO 14064-1:2019, *Greenhouse gases – Part 1: Specification with guidance at the organization level for quantification and reporting of greenhouse gas emissions and removals.* +- [b-ISO 14067] ISO 14067:2018, *Greenhouse gases – Carbon footprint of products – Requirements and guidelines for quantification.* +- [b-Feng] Feng, D., Xu, W., Gao, X., Yang, Y., Feng, S., Yang, X., Li, H (2023), *Carbon Emission Prediction and the Reduction Pathway in Industrial Parks: A Scenario Analysis Based on the Integration of the LEAP Model with LMDI Decomposition. Energies* 2023. 16, 7356. +- [b-IPCC 2019] IPCC 2019, *2019 Refinement to the 2006 IPCC guidelines for national greenhouse gas inventories.* +- [b-Kaya] Kaya, Y (1990), *Impact of carbon dioxide emission control on GNP growth: interpretation of proposed scenarios IPCC energy and industry subgroup, response strategies working group.* +- [b-PAS 2070] PAS 2070: *Specification for the assessment of greenhouse gas emissions of a city.* +- [b-Xu] Xu, M., Liao, C., Huang, Y. et al. (2024), *LEAP model-based analysis to low-carbon transformation path in the power sector: a case study of Guangdong – Hong Kong – Macao Greater Bay Area. Sci Rep.* 14, 7405. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects 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(01/2024)** + +SERIES L: Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant + +Adaptation to climate change + +--- + +**Framework for climate change adaptation in coastal cities using information and communication technology and digital technologies** + +![ITU logo](0538daaa5583c23e17db3a12f2281a55_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue circular emblem with a stylized globe and the letters 'ITU' in white. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +### **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|--------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| Infrastructure including node elements (except cables) | L.200-L.249 | +| General aspects and network design | L.250-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| Optical fibre cable maintenance | L.300-L.329 | +| Infrastructure maintenance | L.330-L.349 | +| Operation support and infrastructure management | L.350-L.379 | +| Disaster management | L.380-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +## Recommendation ITU-T L.1508 + +### Framework for climate change adaptation in coastal cities using information and communication technology and digital technologies + +## Summary + +Recommendation ITU-T L.1508 supports coastal cities and areas to adopt information and communication technologies, as well as digital transformation, to provide innovative solutions for accelerating climate adaptation and enhance climate resilience. + +Coastal cities and areas are particularly vulnerable to the impacts of climate change, including flooding, rising sea level, storm surge, precipitation, and more. The frequency and intensity of these impacts continue to deepen, as a result of climate change. It is, therefore, imperative that coastal cities and areas proactively take climate adaptation actions to minimize these impacts. + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.1508 | 2024-01-13 | 5 | 11.1002/1000/15769 | + +## Keywords + +Climate change, climate change adaptation, information and communication technologies, resilience. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2024 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-----------------------------------------------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 1 | +| 5 Conventions ..... | 2 | +| 6 Climate change and coastal area..... | 2 | +| 7 Climate change adaptation in coastal cities using ICT and digital technologies..... | 3 | +| 7.1 The role of ICTs in tackling climate change ..... | 3 | +| 7.2 ICT for observation and monitoring to predict and forecast climate change..... | 4 | +| 7.3 Climate change adaptation in coastal cities..... | 5 | +| 7.4 The framework of digital transition for tackling climate change ..... | 7 | +| Appendix I – Climate change and coastal areas in the European Union, New Zealand and Mediterranean coastal zones..... | 10 | +| I.1 Climate change and coastal area in European Union ..... | 10 | +| I.2 Climate change and coastal area in New Zealand ..... | 13 | +| I.3 Mediterranean coastal zones: coastal plans and adaptation to climate change..... | 16 | +| Bibliography..... | 18 | + +## Introduction + +Development of the blue economy has been adopted by all countries as a next generation frontier. Different countries and economies have all intensified the need to commercialize their waterfront for tourism, water transport, water sports as well as fisheries and marine science. + +While waterfronts provide the avenue for development of coastal cities for the aforementioned reasons, the cities are exposed to first hand effects of negative climate change. These include, but are not limited to, rising water levels, storms and extreme winds, flooding and extreme temperatures. + +Climate change has therefore become a reality that can no longer be ignored by any sector. + +The blue economy is sustainable use of ocean resources for economic growth, improved livelihoods and jobs, and ocean ecosystem health (see Figure 1). Further information can be found at [b-WB blue]. + +![Infographic titled 'BLUE ECONOMY' showing various sectors: Renewable Energy, Tourism, Climate Change, Fisheries, Maritime Transport, and Waste Management.](573c8f9e728e343b6864e1070c14b8cf_img.jpg) + +**BLUE ECONOMY** + +The blue economy is sustainable use of ocean resources for economic growth, improved livelihoods and jobs, and ocean ecosystem health. The blue economy encompasses many activities. + +**RENEWABLE ENERGY** +Sustainable marine energy can play a vital role in social and economic development + +**TOURISM** +Ocean and coastal tourism can bring jobs and economic growth. Coastal least developed countries and small island developing states receive more than **41 million visitors** per year. + +**CLIMATE CHANGE** +The impacts of climate change on oceans—rising sea-levels, coastal erosion, changing ocean current patterns, and acidification—are staggering. At the same time, **oceans are an important carbon sink** and help mitigate climate change. + +**FISHERIES** +Marine fisheries contribute more than **USD270 billion** annually to global GDP. More sustainable fisheries can generate more revenue, more fish and help restore fish stocks. + +**MARITIME TRANSPORT** +**Over 80 % of international goods** traded are transported by sea, and the volume of seaborne trade is expected to double by 2030 and quadruple by 2050. + +**WASTE MANAGEMENT** +**80 % of Litter** in the ocean is from land-based sources. Better waste management on land can help oceans recover. + +Infographic titled 'BLUE ECONOMY' showing various sectors: Renewable Energy, Tourism, Climate Change, Fisheries, Maritime Transport, and Waste Management. + +L.1508(24) + +Figure 1 – Main areas of the blue economy (Source: [b-WB blue]) + +## Recommendation ITU-T L.1508 + +## Framework for climate change adaptation in coastal cities using information and communication technology and digital technologies + +# 1 Scope + +This Recommendation provides a high-level framework for climate change adaptation in coastal cities and areas. The framework includes a three-step methodology to enhance climate change resilience and accelerate climate change adaptation in coastal cities and areas, including carrying out a flood risk mapping exercise, implementation of information and communication technology (ICT) and digital solutions, and methodology on evaluation of the results. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +None. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following term defined elsewhere: + +**3.1.1 climate change adaptation** [b-ITU-T L.1500]: Adaptation to climate change can be defined as the adjustment in ecological, social or economic systems in response to actual or expected climatic stimuli and their effects. It refers to changes in processes, practices and structures to moderate potential harm or benefit from opportunities associated with climate change. + +## 3.2 Terms defined in this Recommendation + +None. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|---------|------------------------------------------------------------------------------------------------| +| AI | Artificial Intelligence | +| ECLISEA | European advances on Climate services for coasts and Seas | +| FAIR | Flood infrastructure Asset management and Investment in Renovation, adaptation and maintenance | +| FRMP | Flood Risk Management Plan | +| GEF | Global Environment Facility | +| GIS | Geographic Information System | +| ICT | Information and Communication Technology | +| ICZM | Integrated Coastal Zone Management | + +| | | +|------------|---------------------------------------------------------------------------------------------------------------| +| INSeaPTION | Integrating Sea level Projections in climate services for coastal adaptation | +| LISCoAsT | Large scale Integrated Sea level and Coastal Assessment Tool | +| MAP | Mediterranean Action Plan | +| ML | Machine Learning | +| MSP | Maritime Spatial Planning | +| NbS | Nature-based Solution | +| NWRM | Natural Water Retention Measures | +| PAP | Priority Actions Programme | +| PESETA | Projection of Economic impacts of climate change in Sectors of the European Union based on bottom-up Analysis | +| RAC | Regional Activity Centre | +| RBMP | River Basin Management Plan | +| RECONNECT | Regenerating Ecosystems with Nature-based solutions for hydro-meteorological risk reduction | +| RISES-AM | Responses to coastal climate change: Innovative Strategies for high End Scenarios – Adaptation and Mitigation | +| SARCC | Sustainable And Resilient Coastal Cities | +| WFD | Water Framework Directive | + +# 5 Conventions + +None. + +# 6 Climate change and coastal area + +Coastal cities and areas play an important role in society separating land activities from water bodies and fusing the elements generated from both. + +Waterfronts provide the avenue for development of coastal cities for the blue economy, but are exposed to the negative effects of climate change (e.g., rising water levels, storms, extreme winds, flooding and extreme temperatures). + +Earth's land and oceans can be monitored through sensors placed directly on the surface or remotely by satellite. The condition of the atmosphere can be checked for greenhouse gas emissions and wind currents that may presage a hurricane. Satellite images came into the public domain with the launch of LANDSAT 1 in 1972. However, meteorological satellites were used in the 1960s by the World Meteorological Organization (WMO) for its World Weather Watch programme – one of the most valued satellite applications, which is used every day throughout the world. WMO also operates the Global Observing System to monitor weather conditions and alert authorities (see Figure 2). + +![Diagram of the WMO Global Observing System showing various data sources and their connection to a central NMS (National Meteorological Service).](ebff22fb5dd6f50a90e44dca0f82f285_img.jpg) + +The diagram illustrates the WMO Global Observing System. It shows a variety of data sources connected to a central National Meteorological Service (NMS) hub. The sources include: + +- Polar orbiting satellite** and **Geostationary satellite** in the sky, both sending data via red dashed lines to a **Satellite ground station** on the ground. +- Aircraft** flying in the sky, sending data directly to the **NMS**. +- Ocean data buoy** and **Weather ship** in the ocean, sending data via red dashed lines to the **NMS**. +- Satellite soundings** (represented by a cone) from the polar satellite to the ground. +- Ground-based stations including a **Surface station**, **Upper-air station**, and **Automatic station**, all connected to the **NMS**. +- A **Balloon** (weather balloon) in the sky, sending data to the **NMS**. +- The **NMS** is depicted as a building with a person working at a computer, receiving data from all the above sources. + +L.1508(24) + +Diagram of the WMO Global Observing System showing various data sources and their connection to a central NMS (National Meteorological Service). + +**Figure 2 – The WMO Global Observing System (Source: [b-WMO GOS])** + +Appendix I provides an overview and information on climate change and coastal area in European Union (EU), New Zealand and Mediterranean coastal zones. + +# **7 Climate change adaptation in coastal cities using ICT and digital technologies** + +This clause provides information about climate change adaptation in coastal cities using ICT and digital technologies. + +### **7.1 The role of ICTs in tackling climate change** + +ICTs provide an unprecedented ability to collect and analyse environmental information that may encompass the entire terrestrial system, from the depths of the ocean to the upper reaches of the atmosphere. They enable users not only to assess the impact of humans on the environment, but also to manage use of energy and production of greenhouse gases (in the home and in industry). Thus, ICTs are an essential part of efforts to combat climate change and to mitigate its effects [b-ITU ICT]. + +The ICT tools that are available for mitigating climate change are listed as: + +- computer-controlled systems can be used in a multitude of ways to make home, work and manufacturing more energy efficient; +- telecommunications are vital in responding to natural disasters that climate change may bring; +- monitoring vulnerable or dangerous environments is possible with sensor networks; +- satellite observations provide essential data on weather and vegetation patterns; +- ocean buoys communicate data on tsunami or sea level changes, via satellite; +- data can be interpreted and illustrated by geographic information systems (GISs); +- increasing computational power, as well as new algorithms, make for better analysis and modelling of complex environmental and climate systems; +- broadband Internet access makes it easier to share large amounts of data globally; +- distributed (grid) computing allows researchers to explore topics in unprecedented depth. + +ICTs can be used in a number of ways to study and manage the environment, locally and globally. These come under three broad headings: data collection; analysis; and sharing of information. These three phases are described in clauses 7.1.1 to 7.1.3, respectively. + +#### **7.1.1 Collection of data** + +Collection of data is basic to obtaining information useful in tackling the adverse effects of climate change so as to measure the environmental parameters for further interpretation or use. Therefore, data collection is the starting point and relevant tools should be deployed for accuracy. + +Satellite-based sensors monitor and provide information on barometric pressure, water temperature and wave action. This is supplemented by data from land-based sensors, relayed by radio telemetry. Other platforms can also be used, including commercial aircraft, specialized weather observation aircraft, weather balloons and ships. + +#### **7.1.2 Analysis and modelling** + +Once environmental data have been collected, various computational and processing tools are required to perform an analysis. The more powerful the computer, the faster and more complex is the research. As well as conventional supercomputers, the processing power of ordinary computers can be employed for the task, through grid computing. Via the Internet, this method of distributed computing loosely links together machines that may be thousands of kilometres apart and sited in a business, a university or someone's home. In addition to analysing data, the combined computer power can be put to the task of creating models of climate change, for example, that are invaluable for policy-makers. An example of grid computing used for these purposes was the world's largest-ever climate modelling experiment, organized in 2006 by the British Broadcasting Corporation and Climateprediction.net, a consortium of research organizations led by the University of Oxford. More than 250 000 people downloaded computer models that used spare processing power in home computers to predict the future global climate up to 2080. This allowed thousands of models to be tested, each incorporating slightly different figures, and revealed which models were likely to be most accurate. + +#### **7.1.3 Sharing information** + +Grid computing allows data to be shared for in-depth research. One way in which the results can be accessed by all policy-makers is through the Global Earth Observation System of Systems. It is an intergovernmental initiative that arose from the 2002 World Summit on Sustainable Development, and which has at its centre a clearing house to "help users discover, evaluate and use the broadest range of data" (quoted in [b-ITU Labelle]) from a multiplicity of sources. + +Broadband networks in general mean that information on climate change can be circulated around the world via the Internet. More powerful, intelligent and user-friendly applications are becoming available to assist in decision-making. Nowadays, for example, the free services Google Earth and Microsoft Virtual Earth allow users to zoom in on satellite images that map the world in great detail. + +GISs are one of the most effective – and widely used – ways to present environmental data. The systems are created with software that integrates visual and other information from databases on a geographic basis: by clicking on an online map, the user might be able to see data on, for example, environmental conditions or human population. This can include real-time elements, such as the current temperature. + +### **7.2 ICT for observation and monitoring to predict and forecast climate change** + +A range of observation and monitoring data is required to predict and forecast complex changes in climate. At present, sensor technology that measures a variety of environmental changes over a range of locations is available. ICT is being utilized in every part of the process of compiling this huge quantity of data from these sensors in real time to forecast potential future events due to these changes. There are many familiar examples, including weather forecasts from data on the movement of clouds + +and precipitation conditions captured by meteorological satellites [b-NEC adapt]. Figure 3 shows contributions to climate change adaptation utilizing ICT. + +![Figure 3: Contributions to climate change adaptation utilizing ICT. The diagram illustrates a flow from 'Population increase' and 'Climate change' (causing food, water, and energy shortages) through 'Sensing/M2M' (cloud, satellite, city) to 'Big data' (Monitoring and Control), which then leads to 'Realize optimal use of resources (eliminate waste), prepare for risks'.](5b4e774d63e0e0ed73801a9247755e5f_img.jpg) + +The diagram illustrates the contributions of ICT to climate change adaptation. On the left, two blue ovals represent drivers: 'Population increase' and 'Climate change'. 'Population increase' leads to 'Food shortages', 'Water shortages', 'Increased CO2', and 'Energy shortages'. 'Climate change' leads to 'Increased disasters' and 'Etc.'. These drivers point to a central section labeled 'Sensing/M2M'. This section includes a cloud icon, a satellite, a cityscape, and a landscape. Below the cityscape are five boxes: 'Transportation', 'Communications', 'Electricity', 'Water', and 'Gas', collectively labeled 'Social infrastructure'. Below the landscape are five boxes: 'Ecosystems', 'CO2', 'Forests', 'Freshwater', and 'Climate', collectively labeled 'Global environment'. A green arrow labeled 'Various monitoring data' points from the 'Sensing/M2M' section to a 'Big data' icon (a target with concentric circles). From 'Big data', a green arrow points to a 'Monitoring' box containing 'Monitoring and analysis, prediction, ascertainment of indications'. Another green arrow points from 'Monitoring' to a 'Control' box containing 'Supply and demand balance, prevention, precaution, maintenance management'. Finally, a green arrow points from 'Control' to a box at the bottom labeled 'Realize optimal use of resources (eliminate waste), prepare for risks'. The source 'L.1508(24)' is noted in the bottom right corner. + +Figure 3: Contributions to climate change adaptation utilizing ICT. The diagram illustrates a flow from 'Population increase' and 'Climate change' (causing food, water, and energy shortages) through 'Sensing/M2M' (cloud, satellite, city) to 'Big data' (Monitoring and Control), which then leads to 'Realize optimal use of resources (eliminate waste), prepare for risks'. + +Figure 3 – Contributions to climate change adaptation utilizing ICT (Source: [b-NEC adapt]) + +### 7.3 Climate change adaptation in coastal cities + +#### 7.3.1 Rising sea levels and risk of storm surge damage along coasts + +The 5th Assessment Report of the Intergovernmental Panel on Climate Change [b-IPCC] envisions a variety of scenarios and predicts the impacts of climate change. Of these, the worst-case scenario predicts sea surface levels to rise by a maximum 0.82 m by 2100. Causes included melting of ice sheets at the South Pole and in Greenland, glaciers in the Alps, and permafrost. Among the impacts of rising sea levels, first is a reduction of land. In the case of Japan, according to predictions made by the National Institute for Environmental Studies, in the worst case at the end of the year 2100, 83 to 85% (approximately 172 km2) of sand dunes will have disappeared, as will have 12% of tidelands (quoted in [b-NEC sea levels]). In this case, impacts will also be evident on ecosystems that require sand dunes and tidelands. [b-IPCC] also points out that storm surges, coastal flooding and rising sea levels caused by climate change will exert impacts and damage to health in low-lying coastal areas and small island nations, and calls for countermeasures. + +ICT plays a critical role in predicting the degree of sea level rise and its impacts. ICT is indispensable not only for global predictions such as estimations made by the IPCC, but also in making more concrete and detailed predictions at the national and local government level. If those lands that will be able to avoid the tremendous damage of rising sea levels and storm surges in the future based on simulations can be identified using ICT, measures can be taken to avoid impacts or to prevent and mitigate them, such as relocation to higher ground and construction of breakwaters. Further, predicting the occurrence of disasters through ascertainment of changing tide levels in real time using various kinds of sensor, in combination with weather information, enables those affected to evacuate and take countermeasures in advance. + +An increased occurrence of larger and stronger typhoons will reputedly be caused by climate change. In regions where storm surge damage is predicted, the prompt and secure operation of floodgate facilities is called for. + +ICT solutions can contribute to the safety and security of communities through remote monitoring and control of floodgates, both for prompt responses and evacuation prior to storm surge damage and also appropriate maintenance of floodgate facilities. + +An example of storm surge countermeasures utilizing ICT is provided in Figure 4. + +![Figure 4: Example of storm surge countermeasures utilizing ICT. The diagram illustrates a system where a satellite in the cloud sends 'Various monitoring data' to a 'Big data' processing hub. This hub feeds into 'Monitoring' (sea level rise) and 'Control' (floodgate installation and evacuation support). The 'Control' stage leads to 'Reduced damage, prevention, safety and security'. Below the hub, 'Sensing/M2M' from a floodgate facility provides data for 'Observation of damage', 'Tide level', 'Temperature', 'Water level', and 'Air pressure'.](27b06ec9f42b5d727a2630f61a5f1861_img.jpg) + +The diagram illustrates a storm surge countermeasure system. At the top, a cloud icon contains a satellite. A green arrow labeled 'Various monitoring data' points from the satellite to a central circular icon labeled 'Big data'. From this central icon, two green arrows point to two rectangular boxes. The first box is labeled 'Monitoring' and contains the text 'Monitoring of sea level rise anticipating storm surges'. The second box is labeled 'Control' and contains the text 'Installation and operation of floodgates. Expansion of storm surge protection equipment. Evacuation support (evacuation advisories, evacuation directives, evacuation preparation information)'. Below the central 'Big data' icon is a 3D illustration of a floodgate facility on a hill. A blue arrow labeled 'Sensing/M2M' points from the facility to the 'Big data' icon. Below the facility, five small boxes are arranged horizontally, labeled 'Observation of damage', 'Tide level', 'Temperature', 'Water level', and 'Air pressure'. A green arrow points from these boxes to a large green arrow at the bottom labeled 'Reduced damage, prevention, safety and security'. In the bottom right corner, the text 'L.1508(24)' is present. + +Figure 4: Example of storm surge countermeasures utilizing ICT. The diagram illustrates a system where a satellite in the cloud sends 'Various monitoring data' to a 'Big data' processing hub. This hub feeds into 'Monitoring' (sea level rise) and 'Control' (floodgate installation and evacuation support). The 'Control' stage leads to 'Reduced damage, prevention, safety and security'. Below the hub, 'Sensing/M2M' from a floodgate facility provides data for 'Observation of damage', 'Tide level', 'Temperature', 'Water level', and 'Air pressure'. + +**Figure 4 – Example of storm surge countermeasures utilizing ICT** + +#### 7.3.2 Risk of loss of marine ecosystems of great importance to livelihoods in coastal areas + +As detailed in [b-NEC marine], climate change will also exert considerable impacts on sea life. According to [b-IPCC], if sea water temperatures rise by 1 °C, bleaching of coral will increase. Likewise, with an increase of 1 to 2.5 °C almost all coral would be bleached, and anything over 2.5 °C would reputedly cause the annihilation of coral over wide areas. Coral and sea grass beds have a high organism productivity and filter the sea. As the foundation of ecosystem services from the ocean, these impacts cannot be overestimated. Further, rising concentrations of CO2, the representative greenhouse gas, acidify the oceans, wielding impacts on marine ecosystems. + +From the perspective of globally rising demand for food, the preservation of coastal ecosystems for the continued supply of ecosystem services from the oceans, such as supply of marine resources, becomes even more important. While not all the impacts on complex marine ecosystems can be elucidated, changes in key coastal areas must consistently be ascertained, their causes determined, and measures put in place that take into account impacts extending into the future. + +ICT plays an important role in monitoring changes in the marine environment and the preservation of marine ecosystems. When various kinds of sensor are used that measure sea water temperature, acidity, visibility and dissolved oxygen level, measurements can be carried out automatically according to objectives. If measurement data, images, and survey and research results from around the world are shared in the cloud, they will assist in analysis of global current conditions. Further, ICT can also be utilized in aquaculture for the stable supply of declining marine resources. Efficient + +and effective aquaculture can be supported by accumulating and utilizing a variety of expertise and data on feeding methods, water temperature and salinity concentration. + +In the preservation of marine ecosystems, it is first important to ascertain the current state of and secular changes to the ecological environment that exert impacts on ecosystems. Ocean monitoring can be done by using underwater sensors. These sensors are unaffected by weather and can observe 24 h real time marine information, with high precision over long periods of time and wide areas. The creation of observation and monitoring systems of all types is possible by switching sensors and customizing software. + +Concerns have also arisen over the depletion of natural resources due to increased consumption of marine products along with an increasing global-scale population, changes in ecosystems due to the impacts of climate change and overfishing. As such, the importance of aquaculture will increase even more into the future. Utilizing ICT, it is possible to have daily recording and reporting related to aquaculture work, continuous monitoring of water quality and product raised, and analysis of data collected. In so doing, contributions are made to recovery of marine resources and solutions of food problems, as well as the realization of schemes that can provide safe and sound marine products to consumers. + +See Figure 5. + +![Diagram illustrating marine environment monitoring. Underwater sensors are connected to a central monitoring unit, which is linked to a cloud. The cloud provides 24 h real time high-precision observation of marine information and continuous monitoring of water quality and product raised. The system supports aquaculture management.](cab0834804fb031b43865554cc8d06ab_img.jpg) + +The diagram illustrates a marine environment monitoring system. At the bottom, a cross-section of the ocean floor shows several 'Underwater sensors' connected by lines to a central 'Marine environment monitoring' unit. Above this unit, a large cylindrical structure represents a 'Support for aquaculture management' system, containing images of fish. Green arrows point from this central structure up to a 'Cloud' icon. From the cloud, two green arrows point to a person sitting at a computer. The left arrow is labeled '24 h Real time high-precision observation of marine information' and the right arrow is labeled 'Continuous monitoring of water quality and product raised'. + +Diagram illustrating marine environment monitoring. Underwater sensors are connected to a central monitoring unit, which is linked to a cloud. The cloud provides 24 h real time high-precision observation of marine information and continuous monitoring of water quality and product raised. The system supports aquaculture management. + +L.1508(24) + +**Figure 5 – Example of marine environment monitoring** + +### **7.4 The framework of digital transition for tackling climate change** + +ICTs, as well as the related digital transformation, provide innovative solutions that must be adopted to enhance climate resilience and accelerate climate adaptation for coastal cities and areas, which are + +particularly vulnerable to the impacts of climate change, including flooding, rise in sea level, storm surge and precipitation, minimizing the related impacts. + +Figure 6 shows a framework for ICT and digital transition support, starting from cities and infrastructures that need to adapt to climate change effects in coastal areas, through sensors, ICT networks and data analysis (also via digital twins, artificial intelligence (AI) and machine learning (ML) usage). + +![Figure 6: Framework of digital transition for tackling climate change. The diagram consists of four stacked ovals representing a hierarchical framework. From top to bottom: 1. Cloud – Big Data Data analysis (Digital twins, AI/ML, ...) in a blue oval. 2. Networks for data collection (Fixed, mobile, satellite, ...) in an orange oval. 3. Sensing networks (Environmental parameters, ...) in a green oval. 4. Infrastructure of coastal cities and areas in a yellow oval. The text 'L.1508(24)' is located to the right of the bottom oval.](4ee27dbf5ef12e7b58b0ef0937bc5a5e_img.jpg) + +Cloud – Big Data +Data analysis +(Digital twins, AI/ML, ...) + +Networks for data collection +(Fixed, mobile, satellite, ...) + +Sensing networks +(Environmental parameters, ...) + +Infrastructure of coastal cities and areas + +L.1508(24) + +Figure 6: Framework of digital transition for tackling climate change. The diagram consists of four stacked ovals representing a hierarchical framework. From top to bottom: 1. Cloud – Big Data Data analysis (Digital twins, AI/ML, ...) in a blue oval. 2. Networks for data collection (Fixed, mobile, satellite, ...) in an orange oval. 3. Sensing networks (Environmental parameters, ...) in a green oval. 4. Infrastructure of coastal cities and areas in a yellow oval. The text 'L.1508(24)' is located to the right of the bottom oval. + +**Figure 6 – Framework of digital transition for tackling climate change** + +The following high-level framework for climate change adaptation in coastal cities and areas, as a three-step methodology for enhancing climate change resilience, must be adopted: + +- 1) the first step is to carry out a flood risk mapping exercise to identify areas that are most vulnerable to flooding and other climate change impacts; +- 2) the second step is to implement ICT and digital solutions that have proven to be successful in accelerating climate change adaptation actions, including the implementation of early warning or detection systems, emergency communication and evacuation plans; +- 3) the last step is to evaluate the results of the first two and, if necessary, to refine the analysis (step 1) and implementation (step 2). + +The process to utilize ICT and digital technologies for climate change adaptation in coastal cities is detailed in Figure 7. By repeating this cycle, optimal use of resources can be realized, contributing to preparing for risks. + +![Flowchart showing the process to utilize ICT and digital technologies for climate change adaptation. The steps are: 1. Observe and collect data on the state of social infrastructure and the global environment, via sensing. 2. Accumulate data in the Cloud (Big Data). 3. Analyse Big Data collected and ascertain forecasts and predictors (Predictive analytics). 4. Based on forecast and prediction results, enact countermeasures in advance, linked to preparing for risks and optimal use of resources.](33ed1f9b27c7c21c797aa928b0f06851_img.jpg) + +``` +graph TD; A["Observe and collect data on the state of social infrastructure and the global environment, via sensing"] --> B["Accumulate data in the Cloud (Big Data)"]; B --> C["Analyse Big Data collected and ascertain forecasts and predictors (Predictive analytics)"]; C --> D["Based on forecast and prediction results, enact countermeasures in advance, linked to preparing for risks and optimal use of resources"]; +``` + +L.1508(24) + +Flowchart showing the process to utilize ICT and digital technologies for climate change adaptation. The steps are: 1. Observe and collect data on the state of social infrastructure and the global environment, via sensing. 2. Accumulate data in the Cloud (Big Data). 3. Analyse Big Data collected and ascertain forecasts and predictors (Predictive analytics). 4. Based on forecast and prediction results, enact countermeasures in advance, linked to preparing for risks and optimal use of resources. + +**Figure 7 – Process to utilize ICT and digital technologies for climate change adaptation** + +# Appendix I + +## Climate change and coastal areas in the European Union, New Zealand and Mediterranean coastal zones + +(This appendix does not form an integral part of this Recommendation.) + +This appendix provides information from different world regions about climate change and coastal areas, including its current situation, policy and requirements, etc. + +### I.1 Climate change and coastal area in European Union + +EU information about climate change and coastal areas is provided by Climate Adapt [b-CA coast]. See Figure I.1. + +![A scenic view of a rocky coastline with steep cliffs and a small cove, likely in Mallorca, Spain.](a8e5c2ac336eb43cda4e333ea9c73237_img.jpg) + +A photograph showing a rugged coastline with steep, rocky cliffs covered in green vegetation. A small cove with turquoise water is visible in the center, surrounded by more cliffs. The sky is clear and blue. + +A scenic view of a rocky coastline with steep cliffs and a small cove, likely in Mallorca, Spain. + +**Figure I.1 – Mallorca, Llubí, Spain (Image: [b-Kunze]; Source: [b-CA coast])** + +Key messages from Climate Adapt follow [b-CA coast]. + +Climate change is expected to have severe impacts on coastal areas, due to not only sea level rise, and storms and storm surges, but also saltwater intrusion into coastal ecosystems, increased water temperatures and ocean acidification. Ultimately, these effects can cause the loss of multiple ecosystem services provided by coastal areas, of environmental, economic, social, and cultural value for many stakeholders and economic sectors. + +The EU policy framework in place to tackle the impacts of climate change to coastal areas include cross-cutting instruments, such as integrated coastal zone management and maritime spatial planning. + +Other EU directives directly relevant to make coastal zones climate resilient, are the Floods directive, and the Marine strategy framework directive. + +The river basin management plans (RBMPs) of the Water framework directive (WFD) could potentially offer future options to measure the progress of adaptation in coastal areas at the EU level. + +#### I.1.1 Impacts and vulnerabilities + +Sea level rise, and changes in the frequency and magnitude of severe storms and related storm-surges can cause flooding, coastal erosion and the loss of low-lying areas that host habitats of high environmental value as well as human settlements and infrastructures. Sea level rise will also induce + +or increase the risk of saltwater intrusion, further endangering coastal ecosystems. Moreover, expected rises in water temperatures and ocean acidification will contribute to a restructuring of coastal ecosystems, with effects on ocean circulation and biogeochemical cycling. Ultimately, these effects can cause the loss of multiple ecosystem services provided by coastal areas, of environmental, economic, social, and cultural value for many stakeholders and economic sectors. + +The impacts of climate change worsen problems that coastal areas are already facing, due to the increasing urbanization of the coasts and to the presence of infrastructures and multiple human activities, both on land and at sea. Such non-climate-related driving forces interact with climate-related drivers determining the overall vulnerability of natural and human systems of coastal areas. + +#### **I.1.2 Policy framework** + +The 2021 [EU adaptation strategy](#) to climate change, in order to make the adaptation process smarter, recognizes the importance of closing the gap on climate impacts and resilience in all sectors, including coastal areas. Within the objective of making adaptation more systemic, the adaptation strategy promotes [Nature-based solutions \(NbSs\)](#) and ecosystem-based approaches as essential measures to sustain healthy ecosystems against the threats of climate change. For coastal areas, this implies, for example, restoring wetlands and coastal ecosystems. Those approaches make use of blue-green infrastructures as multipurpose, and "no-regret" effective solutions strengthening coastal defence against the impacts of climate change. Carbon removal benefits offered by restored coastal and marine ecosystems are also recognized within the adaptation strategy. In this regard, the Commission promotes new certification mechanisms that will enable robust monitoring and quantification of carbon removal climate benefits offered by many NbSs in coastal areas. + +The EU cross-sector policies and instruments relevant for the climate resilience of coastal areas include [integrated coastal zone management \(ICZM\)](#) and [maritime spatial planning \(MSP\)](#). + +ICZM promotes a strategic and integrated approach to coastal zone management aiming to benefit from synergies and level out inconsistencies across different policies and sectors. The strategic approach required by the EU 2002 [Recommendation on ICZM](#) includes the overarching principle of ecosystem approach to preserve coastal integrity and functioning, against the threats posed by climate change. The 2014 [EU directive on MSP](#) recommends member states to take into account land-sea interactions in the development of their MSP and to take into consideration long-term changes due to climate change in the overall planning process. + +Other EU directives relevant for the sustainable management of coastal areas in the light of adaptation to climate change are: + +- the [Floods directive](#), addressing the assessment and management of flood risk of water courses and coasts in relation to climate variability and climate change; +- the [Marine strategy framework directive](#) establishing a common framework within which member states are required to take the necessary measures to achieve and maintain good environmental status of the EU's coastal and marine waters by 2020 and to protect the resource base upon which [marine-related economic and social activities depend](#). + +These directives have to be implemented coherently with requirements of the [WFD](#), which establishes a common framework for the protection of inland [surface waters, transitional waters, coastal waters and groundwater](#). + +#### **I.1.3 Improving the knowledge base** + +The risks in coastal areas associated with sea level rise for human and ecological systems have been globally assessed in the [Special report on the ocean and cryosphere in a changing climate](#) and in the [IPCC special report on Global warming of 1.5 °C](#). + +The [European atlas of European seas](#) is a web-based tool, providing interactive and diversified information on natural and socio-economic features in the coastal and marine regions of Europe. It also includes information about ICZM projects involved in the former European Commission initiative for ICZM (OURCOAST) initiative. + +Global extreme sea level data and models supporting findings of most recent studies on coastal flooding are available in the [Large scale integrated sea level and coastal assessment tool](#) (LISCOAsT) repository of the [Joint Research Centre data catalogue](#). The Joint Research Centre also ran the [Projection of economic impacts of climate change in sectors of the European union based on bottom-up analysis \(PESETA I-II-III-IV\)](#) projects, within whose scope the impact of climate change on coastal systems has been present since PESETA I in 2009. + +The [Copernicus Climate Change Service](#) (C3S) supports adaptation and mitigation policies of the EU by providing consistent and authoritative information about climate change. The service allows users to access examples of real applications of its climate data store for several sectors, including [Coastal areas](#), demonstrating how climate data can be accessed, transformed and made relevant to address specific climate challenges and climate-related decision-making. + +The European Environment Agency (EEA) indicator [Extreme sea levels and coastal flooding](#) shows the projected change in the frequency of flooding events in Europe according to two different scenarios, requiring coastal protection to be planned at local or regional level. + +A number of research projects supported by different EU programmes have furthermore contributed with knowledge on coastal areas (as, for example, [RISES-AM – Responses to coastal climate change: innovative strategies for high end scenarios – Adaptation and mitigation](#), Flood infrastructure asset management and investment in renovation, adaptation and maintenance (FAIR). Under the [European Research Area for Climate Services](#), [European advances on climate services for coasts and seas \(ECLISEA\)](#) aims to advance coastal climate science concerning sea surface dynamics over European coasts and seas, producing recommendations and best practices about coastal climate and coastal impact aspects. [Integrating Sea level Projections in climate services for coastal adaptation \(INSeaPTION\)](#) aims to co-design and co-develop, together with users, coastal climate services based on state-of-the art sea level rise, impact, adaptation and transdisciplinary science. + +Several EU funded projects contributed to demonstrate the potential of [Nature-based solutions for flood mitigation and coastal resilience](#) (e.g., [Sustainable and resilient coastal cities \(SARCC\)](#), [Adaptation to climate change through management and restoration of European estuarine ecosystems \(Adapto Blues\)](#), [Towards adaptive coastal management \(Adapto\)](#)), providing considerable knowledge and evidence base on this topic, with research efforts especially focused on small-scale interventions. [Regenerarating \[sic\] ecosystems with nature-based solutions for hydro-meteorological risk reduction \(RECONNECT\)](#) aims to rapidly enhance the European reference framework by demonstrating, referencing, upscaling and exploiting large-scale NbSs in rural and natural areas, including coastal zones. + +#### **I.1.4 Supporting investment and funding** + +The EU's [multiannual financial framework \(MFF\) for 2021-27](#) amounts to EUR 1.21 trillion with an additional EUR 807 billion from the [next generation EU](#) recovery instrument. 30% of this budget is earmarked for activities contributing to climate objectives. + +Key EU instruments available to support adaptation are: + +- The [LIFE programme](#) supports both climate change mitigation and climate change adaptation projects, also covering issues of coastal areas. +- The [Horizon Europe](#) includes a mission area for Adaptation to climate change and a mission area for Healthy oceans, seas, coastal and inland waters. The proposed [Mission Starfish 2030](#) aims to restore oceans and waters by 2030 also including an integrated land sea approach for coastal areas. + +A comprehensive overview can be found on the [EU funding of adaptation measures](#) page. + +#### **I.1.5 Supporting the implementation** + +Coastal cities and local governments have significant authority over land-use policies and regulations so that EU and global initiatives (platforms and networks) connecting local governments can give support to the implementation of adaptation measures. Initiatives such as the [Covenant of Mayors for Energy and Climate](#) and [C40](#) (including coastal and delta cities) connect local authorities around the world to collaborate towards a sustainable action on climate change. + +The [European Natural Water Retention Measures](#) (NWRM) platform supports the implementation of the European environmental policy on green infrastructure as a way to contribute to integrated goals dealing with nature and biodiversity conservation and restoration. The NWRM platform covers a wide range of solutions and case studies, some of them are also relevant for coastal areas. + +#### **I.1.6 Floods Directive** + +The [Floods Directive](#) underlines that climate change leads to greater likelihood and adverse impacts of flood events calling on member states to address climate change in their preliminary flood risk assessments and flood risk management plans (FRMPs) and to address likely climate change impacts on the occurrence of floods in the reviews of their FRMPs. Considering sea level rise and the likely increasing risk of storm surges, flooding is expected to have increasing impacts in coastal areas. According to the latest [European Overview of Flood Risk Management Plans](#), 24 out of 26 member states considered at least some aspects of climate change in their FRMPs and 10 provided strong evidence that climate change impacts were considered. However, only a few member states have described methods to check the effectiveness of measures in the face of climate change scenarios, while several others have identified measures that address climate change with a no-regret approach. + +Climate change, with consideration of flooding, is also included in the RBMPs of the [WFD](#) – that also embraces coastal waters – alongside the assessment of pressures from climate change. In [A European Overview of the second River Basin Management Plans](#), only one-third of member states are mentioned as having applied specific measures to adapt to climate change. + +### **I.2 Climate change and coastal area in New Zealand** + +The New Zealand government has released a national adaptation plan that considers the impacts of climate change now and into the future. That government sets out an adaptation strategy [b-NZ NAP] that also takes into account the likely impacts of climate change on coastal areas and how central and local government are preparing for these impacts [b-NZ SEA]. + +#### **I.2.1 Sea level rise** + +From 1880 to 2012, global average temperatures warmed by 0.85°C, as reported in [b-IPCC]. + +The ocean is absorbing 90% of the heat added to the climate system. This warming is causing an expansion of ocean water that, in combination with water from the melting of land-based ice, is causing sea levels to rise. + +The global average sea level rose about 19 cm between 1901 and 2010, at an average rate of 1.7 mm/year. From 1993 to 2016, the global average sea level rose at an average rate of about 3.4 mm/year. + +Due to the influence of regional climate trends and gravitational effects, sea level does not rise uniformly around the globe. Sea levels in New Zealand rose on average by 1.7 mm/year from 1900 to 2008. + +#### **I.2.2 The impacts of climate change on coastal areas** + +Much of New Zealand's urban development and infrastructure is located in coastal areas. This makes it vulnerable to coastal hazards such as coastal erosion, inundation (flooding) by the sea and sea level rise. + +Climate change is likely to bring the following changes: + +- increased frequency, duration and extent of coastal flooding; +- coastal defences are overtopped by waves or high tides more often; +- severe storms increase in intensity and storm surge levels rise; +- some sandy beaches may continue to accrete, but more slowly; +- some gravel beaches are more likely to erode; +- in areas with smaller tidal ranges (e.g., Wellington, the Cook Strait area and the East Coast) the historic high tide mark may be exceeded more often; +- the potential for saltwater to enter underground freshwater aquifers increases. + +#### **I.2.3 Planning for future sea level rise in New Zealand** + +It is important to plan for future sea level rise in advance, developing flexible adaptation plans, rather than relying on a single sea level rise value or scenario. This is because there is a wide range of possible coastal futures with ongoing sea level rise, particularly heading into next century. + +The [coastal hazards and climate change guidance by the NZ Ministry for the Environment](#) provides four scenarios of future sea level rise to use in conducting hazard and risk assessments. + +The guidance provides minimum transitional sea level rise values for use in planning processes for two out of four broad categories of development. + +##### **Category A – Coastal subdivision, greenfield developments and major new infrastructure** + +The [New Zealand Coastal Policy Statement 2010](#) (NZCPS) emphasizes locating such development away from areas prone to coastal hazard risks (including climate change) and avoiding increasing the risk. Therefore, councils considering coastal subdivision, greenfield developments and major new infrastructure should avoid the hazard risk by considering sea level rise over more than 100 years and using the highest sea level rise scenario (H+). + +##### **Category B – Changes in land use and redevelopment (intensification)** + +When considering changes in land use and redevelopment (intensification), councils should conduct a risk assessment using all four sea level rise scenarios and the adaptive pathways planning approach. + +##### **Category C – Existing coastal development and asset planning** + +For planning and decision timeframes out to 2120, councils should use a minimum transitional value for sea level rise of 1 m relative to the 1986-2005 baseline. + +##### **Category D – Non-habitable short-lived assets** + +For planning and decision timeframes out to 2120, councils should use a minimum transitional value for sea- level rise of 0.65 m relative to the 1986-2005 baseline. + +#### **I.2.4 Central government response to planning for sea level rise and increasing coastal risk** + +The [NZCPS](#) provides further direction on planning for development in the coastal zone. + +Each regional council must prepare a regional policy statement, and this regional policy statement must give effect to the NZCPS. Other regional and district plans must also give effect to the NZCPS. + +Under Policy 24 of the NZCPS, "Hazard risks, over at least 100 years, are to be assessed having regard to physical drivers and processes including... sea level rise..." + +For further information, including a copy of the NZCPS, see [NZCPS](#) [Department of Conservation website]. + +#### **I.2.5 Local government response to planning for sea level rise and increasing coastal risk** + +Many local authorities have already started to plan for sea level rise. Some councils have completed coastal hazard assessments and have developed maps showing areas which are expected to be affected over the next 50 to 100 years. + +Other activities being undertaken by local government include: + +- restricting development in coastal erosion areas; +- planning for managed retreat; +- rejecting consents for alterations or extensions to existing buildings in the coastal zone; +- discouraging the construction of defences such as sea walls. + +New Zealand regional land elevation maps (2015-11-19) are available here: + +. + +A series of booklets contain a number of maps showing areas in New Zealand that are low lying and close to the coast, with a focus on urban areas. Land elevation in these maps has been measured using light detection and ranging technology. + +Areas that are both low lying and close to the coast are, in general, most vulnerable to sea level rise. This is certainly the case when it comes to coastal flooding and rising groundwater. Erosion is rather different – a shoreline need not be low lying to be eroded. + +The elevation bands shown on the maps are not hazard zones and should not be interpreted as such. Such maps aid in identifying areas at risk as the sea rises. However, local characteristics are also vitally important. For instance, a low-lying area close to the coast may be protected by a headland or a natural barrier such as a sand dune. In addition, groundwater is only a problem if it is connected to the sea. + +Figure I.2 gives an example of a map of these low-lying coastal lands. + +![Map of low-lying coastal land in Nelson and Mapua, New Zealand. The map shows the coastline with areas of low elevation highlighted in purple (< 50cm), green (50-100cm), and light green (100-150cm). Labels include Mapua, Nelson, Stoke, and Richmond. A scale bar shows 0 to 4 Kilometres. A vertical note on the left states: 'The elevation bands shown on this map are not hazard zones'.](60e9207be66a64332619bb4b667fe67b_img.jpg) + +Map of low-lying coastal land in Nelson and Mapua, New Zealand. The map shows the coastline with areas of low elevation highlighted in purple (< 50cm), green (50-100cm), and light green (100-150cm). Labels include Mapua, Nelson, Stoke, and Richmond. A scale bar shows 0 to 4 Kilometres. A vertical note on the left states: 'The elevation bands shown on this map are not hazard zones'. + +Low-lying coastal land in Nelson and Mapua. + +**Figure I.2 – Low-lying coastal land in Nelson and Mapua (New Zealand)** + +### I.3 Mediterranean coastal zones: coastal plans and adaptation to climate change + +As from "[How coastal plans bolster adaptation to climate change](#)", in addition to hosting critical natural habitats, Mediterranean coastal zones underpin crucial [blue economy](#) activities. As biologically active interfaces where complex land-sea interactions are at play, the coasts are hotspots of climate change vulnerability. Coastal communities must grapple with a [wide array of climate-related risks](#): from sea level rise and havoc-wreaking extreme weather events to the salinization of river deltas and aquifers. + +In this context, the [Priority Actions Programme Regional Activity Centre \(PAP/RAC\)](#) of the Mediterranean Action Plan (MAP) of the United Nations Environment Programme (UNEP) is promoting coastal plans to bolster adaptive capacity. This is achieved by enabling robust territorial planning based on the principles of sustainable development, and by preserving the health of coastal ecosystems – thus making them more resilient to climate change. + +#### I.3.1 Planning under a changing climate + +Coastal plans serve as tools for territory-based multi-stakeholder cooperation to alleviate the pressure exerted on ecosystems. This is done by identifying locally viable pathways to using natural resources sustainably. In doing so, coastal plans capture the principles outlined in the [Integrated Coastal Zone Management \(ICZM\) Protocol](#) to the Convention for the Protection of the Marine Environment and the Coastal Region of the Mediterranean (Barcelona Convention). + +The first coastal plan aligned with the ICZM protocol and encompassing the climate dimension was launched in 2014 in Šibenik-Knin County in Croatia, with the support of the [MedPartnership funded by the Global Environment Facility \(GEF\)](#). The Plan, which was adopted by the County in 2016, earned the [MedAward](#) in 2019. As part of the planning process, Šibenik-Knin County recently initiated the "coastal infrastructure cadastre" with the support of the EU Interreg AdriaAdapt project. Kaštela, another Croatian coastal town, emulated the Šibenik-Knin County example by producing an even more detailed cadastre. The towns of Kaštela, Vodice, and the county of Split-Dalmatia, also in Croatia, recently adopted full-fledged coastal adaptation plans. + +Other coastal plans have been developed in Italy, Montenegro and Morocco. Funding has come from several sources, including the GEF, the EU and the budgets of local or regional governments. Currently, two coastal plans are under preparation with the support of the [GEF-UNEP MedProgramme](#) for the Boka Kotorska Bay in Montenegro and the region of Tanger-Tétouan-Al Hoceima in Morocco. + +In Montenegro, Boka Kotorska Bay – home to a natural and cultural site recognized by the United Nations Educational, Scientific and Cultural Organization – devised a coastal management plan in response to mounting climate-induced threats, including floods, droughts and forest fires. In Morocco, where the national coastal law requires regions to prepare regional plans (referred to locally as *schémas régionaux du littoral*), experts from the PAP/RAC and [Plan Bleu](#) RACs of UNEP/MAP are supporting coastal planning in Tanger-Tétouan-Al Hoceima. Plan Bleu is implementing its [Climagine foresight methodology](#) to support the elaboration of the coastal plans in Morocco and Montenegro. + +PAP/RAC has developed a [wealth of tools](#) to assist local governments and their partners in devising robust coastal plans, including a [knowledge platform](#) on coastal adaptation. Although initially aimed at Adriatic countries, this platform has received visits from more than 150 countries worldwide, thus demonstrating its relevance to common coastal challenges around the Mediterranean and beyond. + +Working in synergy with PAP/RAC, Plan Bleu is underpinning the conduct of regional climate risk assessments, engaging researchers, decision makers, local communities and the private and financial sectors to support climate change adaptation solutions. Plan Bleu is also piloting a local foresight exercise in the Agglomeration of Sophia-Antipolis in the South of France, where the Centre is facilitating territorial dialogue on challenges posed by climate change in the coastal context while focusing on solutions at the community level. + +#### **1.3.2 Coastal plans as locally relevant frameworks for climate action** + +The most effective coastal plans are those developed in an inclusive manner, integrating gender equality and embodying inclusive partnerships among government, academia, civil society and businesses. The process leading to the development of a coastal plan provides plenty of opportunities for genuine whole-of-society engagement for adaptation and, by the same token, the achievement of several Sustainable Development Goals. + +Coastal plans constitute conducive frameworks within which NbSs, which require wide uptake and collaboration, can be successfully introduced to build local adaptation muscle. Such solutions include, for instance, the restoration or preservation of wetlands, dunes and salt marshes. + +One of the main contributions of coastal plans is also to infuse the essence of the ICZM protocol in local development planning. This is a crucial because the full implementation of the [Barcelona Convention and its six Protocols](#) constitutes a prerequisite to achieving healthier and, consequently, more resilient marine and coastal ecosystems that can underpin adaptation efforts in the Mediterranean. + +# Bibliography + +- [b-ITU-T L.1500] Recommendation ITU-T L.1500 (2014), *Framework for information and communication technologies and adaptation to the effects of climate change*. +- [b-ITU ICT] International Telecommunication Union (2024). *Tackling climate change – The role of ICT*. Geneva: International Telecommunication Union. Available [2024-03-20] at: +- [b-ITU Labelle] Labelle, R., Rodschat, R., Vetter, T., Ludwig, K. (2008). *ICTs for e-environment – Guidelines for developing countries, with a focus on climate change*. Geneva: International Telecommunication Union. Available [2024-05-11] at: +- [b-CA coast] Climate Adapt (Internet). *Coastal areas*. Copenhagen: European Climate Adaptation Platform. Available [2024-03-21] at: +- [b-IPCC] IPCC (2024). *Fifth assessment report*. Geneva: Intergovernmental Panel on Climate Change. Available [2024-03-20] at: +- [b-Kunze] Kunze, S. (2015). *Unsplash*. Available [2024-03-26] at: +- [b-NEC adapt] Working Group II: Impacts, Adaptation and Vulnerability in the 5th Assessment Report of the IPCC (1994-2024). *What ICT can do for climate change adaptation*. Tokyo: NEC Corporation. Available [2024-05-10] at: . +- [b-NEC marine] Working Group II: Impacts, Adaptation and Vulnerability in the 5th Assessment Report of the IPCC (2020). *Loss of marine ecosystems*. Tokyo: NEC Corporation. Available [2024-03-21] at: [https://www.nec.com/en/global/csr/eco/pdf/nec\\_k7\\_en.pdf](https://www.nec.com/en/global/csr/eco/pdf/nec_k7_en.pdf) +- [b-NZ NAP] NZ Ministry for the Environment. *Aotearoa New Zealand's first national adaptation plan released*. Wellington: Ministry for the Environment. Available [2024-03-22] at: [Aotearoa New Zealand's first national adaptation plan released | Ministry for the Environment](https://www.environment.govt.nz/what-government-is-doing/areas-of-work/climate-change/adapting-to-climate-change/adapting-to-sea-level-rise/) +- [b-NZ SEA] NZ Ministry for the Environment. *Adapting to sea-level rise*. Wellington: Ministry for the Environment. Available [2024-03-22] at: +- [b-NEC sea levels] NEC (2020). *Rising sea levels and storm surge damage*. Tokyo: NEC Corporation. Available [2024-05-11] at: [https://www.nec.com/en/global/sustainability/eco/pdf/nec\\_k1\\_en.pdf](https://www.nec.com/en/global/sustainability/eco/pdf/nec_k1_en.pdf) +- [b-WB blue] World Bank (2017). *What is the blue economy?* Washington, DC: World Bank. Available [2024-03-22] at: +- [b-WMO GOS] WMO (2020). *Observation components of the Global Observing System*. Geneva: World Meteorological Organization. Available [viewed 2024-05-11] at: + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|----------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.151-202010-I_PDF-E/14a22f23ced8ba1d63ece69861dbaacc_img.jpg b/marked/L/T-REC-L.151-202010-I_PDF-E/14a22f23ced8ba1d63ece69861dbaacc_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..1d8deae6031c18707104a329a7eae044811bbb4b --- /dev/null +++ b/marked/L/T-REC-L.151-202010-I_PDF-E/14a22f23ced8ba1d63ece69861dbaacc_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:f418e2fcf77b057e807e60d0a0a741dd98ab9ee337764072def10cd9ce79d647 +size 5986 diff --git a/marked/L/T-REC-L.151-202010-I_PDF-E/967c30813761a8952ecc5e16bf42ea45_img.jpg b/marked/L/T-REC-L.151-202010-I_PDF-E/967c30813761a8952ecc5e16bf42ea45_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..9a3f8f49c9788ebd51a1ad6f686bd407c2ec81ff --- /dev/null +++ b/marked/L/T-REC-L.151-202010-I_PDF-E/967c30813761a8952ecc5e16bf42ea45_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:faa85b5268a45ff9fd709f6620065056b8b975e215fd58b10f284a85872ae12f +size 91456 diff --git a/marked/L/T-REC-L.1510-202510-I_PDF-E/84a1d09fb489061482111515543b60dc_img.jpg b/marked/L/T-REC-L.1510-202510-I_PDF-E/84a1d09fb489061482111515543b60dc_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..abda52cbb1047d6649f89e40c898a1c33bed7267 --- /dev/null +++ b/marked/L/T-REC-L.1510-202510-I_PDF-E/84a1d09fb489061482111515543b60dc_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:6f3b7e07231c0f3e116c99c493bdda98ecd52313b6735faa6cea23815cf3162b +size 7190 diff --git a/marked/L/T-REC-L.1510-202510-I_PDF-E/cfda9df1319e04207eb28bcefd1dab7b_img.jpg b/marked/L/T-REC-L.1510-202510-I_PDF-E/cfda9df1319e04207eb28bcefd1dab7b_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..b4dda14f0d49cd0dafc8ba22919f647765d35014 --- /dev/null +++ b/marked/L/T-REC-L.1510-202510-I_PDF-E/cfda9df1319e04207eb28bcefd1dab7b_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:1741ba56c840848d0d02aec14a2c291288cb7537826387c00e8398721e17a803 +size 43818 diff --git a/marked/L/T-REC-L.1510-202510-I_PDF-E/raw.md b/marked/L/T-REC-L.1510-202510-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..e5a1ca482ddbe07812740f666e2cf99d7542595c --- /dev/null +++ b/marked/L/T-REC-L.1510-202510-I_PDF-E/raw.md @@ -0,0 +1,539 @@ + + +# Recommendation + +## **ITU-T L.1510 (10/2025)** + +SERIES L: Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant + +Adaptation to climate change + +--- + +## **Environmental key performance indicators for digital infrastructure adapting to climate change** + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue circular emblem with a stylized globe and the letters 'ITU' in white. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +### **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|--------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| Infrastructure including node elements (except cables) | L.200-L.249 | +| General aspects and network design | L.250-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| Optical fibre cable maintenance | L.300-L.329 | +| Infrastructure maintenance | L.330-L.349 | +| Operation support and infrastructure management | L.350-L.379 | +| Disaster management | L.380-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1510 + +## Environmental key performance indicators for digital infrastructure adapting to climate change + +## Summary + +Recommendation ITU-T L.1510 defines key performance indicators (KPIs) for assessing the environmental impact of digital infrastructures, including greenhouse gas (GHG) emissions, water usage, power supply, ecosystem effects, waste management and indirect enablement of GHG emission reduction. It specifies unified methodologies for KPI calculation and reporting, enabling harmonized, transparent and comparable sustainability assessment across the industry. The Recommendation builds on existing frameworks and best practices, providing a foundation for evolving reporting standards and alignment with other industry bodies, with the ultimate aim of achieving a single, industry-wide agreed set of KPIs. + +## History\* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.1510 | 2025-10-22 | 5 | 11.1002/1000/16420 | + +## Keywords + +Climate change, digital infrastructure, KPIs, sustainability. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, and information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2025 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-----------------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 2 | +| 3.1 Terms defined elsewhere ..... | 2 | +| 3.2 Terms defined in this Recommendation..... | 2 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 3 | +| 6 Overview of KPIs for sustainable digital infrastructure ..... | 3 | +| 7 Environmental sustainability KPI metrics for digital infrastructures ..... | 4 | +| 7.1 Metric categories used to set goals ..... | 4 | +| 7.2 Key metrics..... | 6 | +| 8 Key metrics for reporting in digital infrastructure..... | 14 | +| 9 Setting targets for digital infrastructures ..... | 15 | +| 10 Implementation of digital infrastructure KPIs for environmental sustainability ..... | 16 | +| Appendix I – An example of setting metric targets for digital infrastructures ..... | 17 | +| Bibliography..... | 18 | + +# Introduction + +The shift from corporate social responsibility (CSR) to environmental, social and governance (ESG) reflects the capital market's refined approach to evaluating companies, emphasizing the integration of business value with societal well-being. As carbon neutrality becomes a global priority, businesses, particularly in the information and communication technology (ICT) sector, are central to driving sustainable progress. Environmental key performance indicators (KPIs), a key pillar of ESG performance, require urgent standardization to support science-based targets and long-term strategies. + +For mobile network operators and other digital infrastructure providers, integrating climate action into core operations is critical. This includes improving energy efficiency – such as optimizing data-to-energy ratios – while deploying energy-saving technologies and leveraging digital solutions that also enable customers to reduce their carbon footprints. Evidence from industry studies shows that the customer benefits can significantly outweigh the providers' own footprints. + +Transparent, harmonized and science-based KPIs are essential to track progress, compare performance and guide continuous improvement. This Recommendation responds to that need by identifying and defining KPIs for green and sustainable digital infrastructures, enabling the sector to adapt to climate change while advancing ESG excellence. + +## Recommendation ITU-T L.1510 + +## Environmental key performance indicators for digital infrastructure adapting to climate change + +# 1 Scope + +This Recommendation identifies the environmental key performance indicators (KPIs) set for the digital infrastructures, provides the guidelines on how to set and use the environmental KPIs to adapt to climate change challenges. In order to identify the high climate impact factors and mitigate their carbon footprints, this Recommendation clarifies six categories of digital infrastructure metrics, namely, energy KPI, greenhouse gas (GHG) emissions KPI, water usage KPI, waste KPI, ecosystem KPI and enablement KPI. From these categories, several key metrics for reporting environmental sustainability are established. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a standalone document, the status of a Recommendation. + +- [[ITU-T L.1332](#)] Recommendation ITU-T L.1332 (2018), *Total network infrastructure energy efficiency metrics*. +- [[ITU-T L.1333](#)] Recommendation ITU-T L.1333 (2022), *Carbon data intensity for network energy performance monitoring*. +- [[ITU-T L.1400](#)] Recommendation ITU-T L.1400 (2023), *Overview and general principles of methodologies for assessing the environmental impact of information and communication technologies*. +- [[ITU-T L.1410](#)] Recommendation ITU-T L.1410 (2024), *Methodology for environmental life cycle assessments of information and communication technology goods, networks and services*. +- [[ITU-T L.1420](#)] Recommendation ITU-T L.1420 (2012), *Methodology for energy consumption and greenhouse gas emissions impact assessment of information and communication technologies in organizations*. +- [[ITU-T L.1480](#)] Recommendation ITU-T L.1480 (2025), *Enabling the Net Zero transition – Assessing how the use of information and communication technology solutions impacts greenhouse gas emissions of other sectors*. +- [ISO/IEC 30134-2] ISO/IEC 30134-2:2016, *Information technology – Data centres – Key performance indicators – Part 2: Power usage effectiveness (PUE)*. +- [ISO/IEC 30134-3] ISO/IEC 30134-3:2016, *Information technology – Data centres – Key performance indicators – Part 3: Renewable energy factor (REF)*. +- [ISO/IEC 30134-6] ISO/IEC 30134-6:2021, *Information technology – Data centres key performance indicators – Part 6: Energy Reuse Factor (ERF)*. +- [ISO/IEC 30134-8] ISO/IEC 30134-8:2022, *Information technology – Data centres key performance indicators – Part 8: Carbon usage effectiveness (CUE)*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 carbon usage effectiveness (CUE)** [ISO/IEC 30134-8]: Ratio of the data centre annual CO2 emissions and IT equipment energy demand. + +**3.1.2 infrastructure (facility)** [b-ITU-T L.1302]: Equipment that supports information and communication technology (ICT) equipment, e.g., power delivery components and cooling system components. + +**3.1.3 power usage effectiveness (PUE)** [ISO/IEC 30134-2]: Ratio of the data centre total energy consumption to information technology equipment energy consumption, calculated, measured or assessed across the same period. + +**3.1.4 renewable energy factor (REF)** [ISO/IEC 30134-3]: Ratio of the renewable energy owned and controlled by a data centre to the total data centre energy. + +**3.1.5 water usage effectiveness (WUE)** [ISO/IEC 30134-9]: Ratio of the data centre water consumption divided by the energy consumed by IT equipment. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 energy reuse factor (ERF)**: Ratio of reused energy to total energy consumption for a digital infrastructure. + +**3.2.2 digital infrastructure**: Total physical and software-based infrastructure necessary to deliver digital goods, products and services. + +NOTE – This includes data centres, fibre infrastructure, mobile network infrastructure, server hardware, personnel, IT virtualization and infrastructure software and operating systems. + +**3.2.3 mean species abundance density**: Indicator representing the intactness of species assemblages per km2 in an area, based on a comparison between an impacted habitat and an undisturbed reference habitat. + +NOTE – When expressed as a normalized index, it ranges from 0 to 1 and is used to derive a global biodiversity score (GBS). + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|---------------------------------------| +| CHP | Combined Heat and Power | +| CSR | Corporate Social Responsibility | +| CUE | Carbon Usage Effectiveness | +| DCIM | Data Centre Infrastructure Management | +| EAC | Energy Attribute Certificate | +| EPD | Environmental Product Disclosures | +| ESG | Environmental, Social and Governance | + +| | | +|------|-------------------------------------------| +| ERF | Energy Reuse factor | +| GBS | Global Biodiversity Score | +| GHG | Greenhouse Gas | +| HFC | Hydro-Fluorocarbon | +| HVAC | Heating, Ventilation and Air Conditioning | +| ICT | Information and Communication Technology | +| IT | Information Technology | +| KPI | Key Performance Indicator | +| MSA | Mean Species Abundance | +| NGO | Non-Government Organization | +| PFC | Perfluorinated Compound | +| PPA | Power Purchase Agreement | +| PUE | Power Usage Effectiveness | +| REC | Renewable Energy Certificate | +| REF | Renewable Energy Factor | +| SDO | Standards Development Organization | +| UPS | Uninterrupted Power Supply | +| VER | Verified Emission Reduction | +| WUE | Water Usage Effectiveness | + +# 5 Conventions + +None. + +# 6 Overview of KPIs for sustainable digital infrastructure + +Digital infrastructure, including both network infrastructure and information technology (IT) infrastructure, represents more than 35% of digital energy consumption worldwide and 2% of worldwide CO2 [b-ETSI Mag]. To help operators progress in reducing environmental impacts during operation, European Telecommunications Standards Institute (ETSI) has published several global KPIs. + +The ETSI ATTM (Access, Terminals, Transmission, Multiplexing) committee has defined a set of standards, both for telecom operators [b-ETSI ES 205 200 series] and for European users [b-ETSI EN 305 200 series], that define global KPIs as well as user guides [b-ETSI TS 105 200 series]. These KPIs are driven by a yearly master indicator (e.g., yearly energy efficiency and carbon intensity) related to service provided (ICT energy for ICT sites, data exchanged for network) combined with several weighted bonuses. They reflect the conformance of a network or group of ICT sites to a user-defined policy for sustainability, defining which consideration is given to what bonus. + +These KPIs consider all energy sources enabling ICT operations (e.g., ICT equipment, cooling, power, monitoring and security infrastructures) from various sources (e.g., grid, district cold and heat, diesel and combined heat and power (CHP)), including renewables. KPIs are presented as site yearly energy consumption and a class which is a banded value of a performance indicator. When applied to groups of sites, this indicator is the weighted average of the classes. + +# 7 Environmental sustainability KPI metrics for digital infrastructures + +According to [b-Schneider 2023], a technical guide on environmental sustainability metrics for data centres was issued. This concept can be extended from data centres to general digital infrastructures. As shown in Figure 1, a digital infrastructure operator should first set their overarching company goals and then select the metrics, set metric targets and measure their progress towards the goals, year over year. Infrastructure operators shall consult frameworks and standards for each of these steps. + +![Flowchart illustrating the steps to optimize a digital infrastructure's sustainability. The process starts with 'Set new target level', followed by 'Select metrics', 'Set metrics goals', and 'Report and verify'. These four steps are enclosed in a dashed red box labeled 'Scope of this Recommendation'. The process then continues to 'Set action plans', 'Monitor and optimize', and a decision diamond 'Meet metrics goals'. If 'Yes', the process loops back to 'Set new target level'. If 'No', it loops back to 'Set action plans'.](cfda9df1319e04207eb28bcefd1dab7b_img.jpg) + +``` +graph TD; subgraph Scope [Scope of this Recommendation]; A[Set new target level] --> B[Select metrics]; B --> C[Set metrics goals]; C --> D[Report and verify]; end; D --> E[Set action plans]; E --> F[Monitor and optimize]; F --> G{Meet metrics goals}; G -- Yes --> A; G -- No --> E; +``` + +L.1510(25) + +Flowchart illustrating the steps to optimize a digital infrastructure's sustainability. The process starts with 'Set new target level', followed by 'Select metrics', 'Set metrics goals', and 'Report and verify'. These four steps are enclosed in a dashed red box labeled 'Scope of this Recommendation'. The process then continues to 'Set action plans', 'Monitor and optimize', and a decision diamond 'Meet metrics goals'. If 'Yes', the process loops back to 'Set new target level'. If 'No', it loops back to 'Set action plans'. + +**Figure 1 – Steps to optimize a digital infrastructure's sustainability** + +## 7.1 Metric categories used to set goals + +As an industry, progress on environmental sustainability goals includes adopting standardized metrics for measurement, making these metrics well understood throughout the market and the ICT industry, and reporting them publicly and regularly (e.g., semi-annually and annually). + +### 7.1.1 Metric category 1 – energy consumption + +As total digital infrastructure energy consumption is increasing, along with the growing distributed renewable energy supply, digital infrastructure operators are required to have a clear understanding of their energy sources. Measuring energy from all sources determines the carbon-intensity of a digital infrastructure's energy mix and supports operators to improve sustainability. Reporting energy consumption, energy efficiency and renewable energy use is important for digital infrastructure operators to show their progress on efforts to minimize their carbon footprint. + +### **7.1.2 Metric category 2 – GHG emissions** + +CO2 and other gases such as CH4, perfluorinated compounds (PFCs) and hydro-fluorocarbons (HFCs) are classified as GHGs. These GHG emissions, also referred to as "carbon emissions", are a major contributor to climate change and one of the most pressing issues facing society today. According to [ITU-T L.1410] and [ITU-T L.1420], as well as the GHG protocol and [b-ISO 14064], there are three categories of GHG emissions: scope 1, scope 2 and scope 3. Reporting GHG emissions is important for digital infrastructure operators to show their efforts in controlling climate change. + +### **7.1.3 Metric category 3 – water usage** + +Water shortages are becoming a serious problem in many regions. It is important to understand water use within digital infrastructures and at power plants. Decreasing water usage is a focus area for many digital infrastructure operators and local jurisdictions. There are different types of technologies (e.g., dry cooler with adiabatic evaporation and liquid cooling) that are being implemented to reduce direct water usage. As a result, digital infrastructures are using less water on average than they used to. Operators are also investing in water replenishment programmes to save water indirectly. Reporting water usage and savings are becoming more important as a part of overall sustainability goals. + +#### **7.1.4 Metric category 4 – waste generation** + +Digital infrastructures are challenged with a unique waste profile compared to other industrial operations. In order to meet circularity goals/targets, digital infrastructure operators need to understand their waste profile (especially e-waste and end-of-life batteries) with tailored digital infrastructure metrics. Minimizing waste from the supply chain and diverting it out of landfills through reuse and recycling is a key strategy for environmental sustainability. Circular economy design methodologies and processes support improvements in this area. Reporting waste generation and diversion is emerging in importance for digital infrastructure operators and is likely to become commonplace in the near future. + +#### **7.1.5 Metric category 5 – local ecosystem impacts** + +Digital infrastructures have direct and indirect impact on the local ecosystem (i.e., biodiversity) including land, sound level and species. For example, digital infrastructures have a direct impact on the land they are built upon and an indirect land impact from their supply chain. Measuring the impacts to land is common in industries like mining but new to the digital infrastructure industry. The heating, ventilation and air conditioning (HVAC) equipment (e.g., cooling towers, dry coolers and ducts) and diesel gensets in a digital infrastructure can produce high levels of noise, which draws attention from local jurisdictions. Greenfield digital infrastructure construction also impacts the quantity and diversity of species around it. Reporting the impact on the local ecosystem is also emerging in importance for infrastructure operators and likely to become commonplace in the near future. + +#### **7.1.6 Metric category 6 – green enablement** + +The ICT industry has a significant capacity to empower vertical industries and society as a whole in reducing emissions. For example, by leveraging digital technologies for remote work and business transactions, carbon emissions from travel can be effectively reduced. The GHG emissions reductions achieved through this empowerment can often be several times greater than the carbon emissions self-created by ICT operators themselves. Overall, to maximize the ICT industry's impact on reducing carbon emissions across society, it is essential to report and monitor the emissions reductions enabled by these technologies. + +## 7.2 Key metrics + +#### 7.2.1 Key metrics of category 1 – energy consumption + +The key metrics of energy consumption are listed in Table 1. + +**Table 1 – The key metrics of energy consumption** + +| Key metric | Description | Application | Reference | +|------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Total energy consumption (kWh) | The total energy consumed to operate a digital infrastructure. This is typically the electrical energy drawn from the utility grid but would also include any on-site energy production from generators, solar or wind. Energy imported in the form of natural gas, steam or chilled water should also be counted. |
  • – Decision-making during the design phase to reduce operational costs and environmental impacts, including site selection and cooling solutions.
  • – Tracking energy efficiency improvements to support the reduction of carbon mix in the energy supply throughout the design and operation phases.
  • – Balancing the trade-offs between energy and water consumption in digital infrastructure.
| [ITU-T L.1332] and [ITU-T L.1333] | +| PUE | Digital infrastructure's total energy consumption divided by the IT energy consumption. |
  • – Comparison across different digital infrastructures by normalizing to the IT load.
  • – Awareness of variation factors such as load percentage, resiliency (e.g., tier) and climate.
  • – Easy management of overhead energy use of facilities in digital infrastructure facilities due to the simplicity of PUE.
| [ISO/IEC 30134-2] | +| Total renewable energy consumption (kWh) | Total renewable energy that is owned, controlled or purchased for use at a digital infrastructure. |
  • – Supporting the reduction of scope 2 carbon emissions by increasing the share of renewable energy.
  • – Tracking of scope 2 reduction plans and reporting of renewable energy use.
  • – Supporting digital infrastructure operators to obtain renewable energy, including on-site renewable energy production (self-generated) and purchased renewable energy through various procurement methods, such as long-term power purchase agreements (PPAs), green tariffs or buying energy attribute certificates (EACs).
| International Energy Agency (IEA). (2024). Renewable energy consumption . IEA. Retrieved from https://www.iea.org/reports/renewables | +| REF | REF accounts for the energy procured through renewable energy certificates (RECs) and consumed by the digital infrastructure. Achieving an REF=1.0 indicates all of the digital infrastructure's energy is renewable. |
  • – Comparisons across different digital infrastructures on renewable energy ratio.
  • – Tracking renewable energy consumption as digital infrastructure load changes.
| [ISO/IEC 30134-3] | + +**Table 1 – The key metrics of energy consumption** + +| Key metric | Description | Application | Reference | +|------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------| +| ERF | ERF values range from 0 to 1.0, with 0 meaning no heat energy is reused and 1.0 meaning that all of the digital infrastructure's heat energy is re-used/exported. |
  • – Encouraging digital infrastructure operators and municipalities to explore waste heat reuse opportunities.
  • – Supporting integration of waste heat into nearby district heating systems.
| [ISO/IEC 30134-6] | + +#### 7.2.2 Key metrics of category 2 – GHG emissions + +The key metrics of GHG emissions are listed in Table 2. + +**Table 2 – The key metrics of GHG emissions** + +| Key metric | Description | Application | Reference | +|--------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------| +| Scope 1 – direct GHG emissions (mtCO 2 e) | Direct emissions that occur from sources controlled or owned by the digital infrastructure organization. Sources include combustion of fuels from backup gen-sets, leakage of SF 6 from medium voltage switchgear, HFCs or other medium released by cooling systems, transportation of materials, and workers using mobile combustion sources owned or controlled by the organization, such as trucks and cars. |
  • – Supporting implementation of solutions to reduce or eliminate scope 1 emissions during the design phase of the facility.
  • – Replacement of backup genset with other forms of energy storage.
| [ITU-T L.1400], [b-ISO 14064-1] and [b-ISO 14064-2] | +| Scope 2 – indirect GHG emissions (mtCO 2 e) | This metric is used to measure the indirect emissions from purchased or acquired electricity, steam, heat and cooling (as applicable) that are controlled or owned by a digital infrastructure organization. The organization shall quantify indirect GHG emissions from the generation of purchased electricity, heat or steam consumed by the organization, within the selected organizational boundaries. For many organizations, purchased electricity represents one of the largest sources of GHG emissions and one of the | This metric can be evaluated from two perspectives:
  • – The location-based metric that can be used to describe the GHG intensity of grids and assess risks/opportunities aligned with local grid resources and emissions.
  • – The market-based metric that indicates the organization's procurement actions and assesses risks/opportunities with contractual electricity procurement.
This dual metric can assess a variety of mitigation options to lower scope 2 carbon emissions and provides transparency for stakeholders or investors. The GHG Protocol Scope 2 Guidance [b-GHG Scope 2] identifies these two methods for scope 2 accounting. | [ITU-T L.1400], [b-ISO 14064-1], [b-ISO 14064-2] and [b-GHG Scope 2] | + +**Table 2 – The key metrics of GHG emissions** + +| Key metric | Description | Application | Reference | +|--------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| | most significant opportunities to reduce these emissions. Since ICT organizations in general are not energy producers, most emissions from internal operations will be reported in this category. | | | +| Scope 3 – indirect GHG emissions (mtCO 2 e) | Other indirect GHG emissions, for example, from the value chain (embodied carbon), business travel and waste management. | – Recognition as the primary source of carbon impact as renewable energy usage increases. | [ITU-T L.1400], [b-ISO 14064-1] and [b-ISO 14064-2] | +| CUE (kg CO 2 e/kWh) | CUE is measured in three categories:
– CUE1 that focuses on CO 2 only,
– CUE2 that focuses on CO 2 equivalent, and
– CUE3 that is reserved for future use.

The ideal CUE value is 0.0, which indicates there are no carbon emissions associated with the data centre's operations. | – Site selection in the design phase.
– Measuring the effectiveness of continuous improvement programmes in the operation phase. | [ISO/IEC 30134-8] | +| Total carbon offsets (mtCO 2 e) | Total reduced or avoided carbon emissions through financial mechanisms outside of a digital infrastructure's operation. Carbon offsets, known as verified emission reductions (VERs) or carbon credits, are recognized by governments, independent third-party organizations and NGOs. | – Quantification of purchased carbon offsets for unmitigated scope 1 and scope 3 emissions.
– Providing transparency in reporting and visibility into actual carbon reduction efforts versus offsetting.
– Economic incentive mechanism for carbon reduction and carbon market stabilization. | United Nations Framework Convention on Climate Change (UNFCCC). (2018). The Clean Development Mechanism: A tool for sustainable development . United Nations. Retrieved from https://unfccc.int/process/the-kyoto-protocol/mechanisms/clean-development-mechanism | +| Hourly renewable supply and consumption matching (%) | Ratio of renewable energy generation matched to real-time energy consumption within a digital infrastructure organization. | – Enhancement of transparency in the real-time matching of renewable energy production and consumption, targeting a 100% match of renewable production and consumption on an hour-by-hour basis. | EPA (U.S. Environmental Protection Agency) What is 24/7 Hourly Matching of Electricity? The EPA defines 24/7 hourly matching as purchasing electricity generation so that it matches a consumer's hourly consumption on a continuous basis, ideally in the same regional grid. | + +#### 7.2.3 Key metrics of category 3 – water usage + +The key metrics of water usage are listed in Table 3. + +**Table 3 – The key metrics of water usage** + +| Key metric | Description | Application | Reference | +|---------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------| +| Total site water usage (m 3 ) | Total on-site water usage for the operation of digital infrastructure, defined as the net value covering water withdrawals, evaporation and discharge, accounting for potable, non-potable and reclaimed water in each category. |
  • – Reporting of direct on-site water usage by digital infrastructure organizations, similar to scope 1 GHG emissions.
  • – Prediction of water use during the design phase to support the selection of optimized cooling technologies.
  • – Use of reclaimed water for cooling towers, to reduce consumption of fresh/potable water.
  • – Tracking of operational water use to detect issues (e.g., leaks) and establish a baseline for ongoing improvements.
| [ISO/IEC 30134-9] | +| Total source energy water usage (m 3 ) | Total water used to produce the energy that digital infrastructure consumes. This is generally from the utility's electricity production. |
  • – Illustration of off-site (indirect) water usage by digital infrastructure organizations, similar to scope 2 GHG emissions.
  • – Support for optimizing water use related to energy consumption, such as through utility selection.
  • – Evaluation of trade-offs between site water usage, indirect water usage and energy consumption.
  • – Holistic understanding of water use at both the site and energy source, to minimize total water consumption.
| N/A | +| WUE (m 3 /MWh) | WUE measurement is in three categories: |
  • – Consideration needed in design phases.
  • – Tracking continued reduction of water usage in the operation phase.
| [ISO/IEC 30134-9] | + +**Table 3 – The key metrics of water usage** + +| Key metric | Description | Application | Reference | +|---------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------| +| |
  • – WUE1 that never considers water reuse,
  • – WUE2 that considers non-industrial reuse in water output, and
  • – WUE3 that considers industrial and non-industrial reuse in water output and water consumption of energy production in water input.

For digital infrastructure, WUE1 is recommended, since non-industrial water reuse is not typical or significant.

| | | +| Water replenishment (m 3 ) |

Total water reduced or saved through financial mechanisms outside of a digital infrastructure's operation. Investments in water offset programmes is also known as water balancing. In essence, a digital infrastructure operator pays others to return water to ecosystems and uses that to offset water usage from digital infrastructure operations.

|
  • – Quantification of water replenishment to the ecosystem to offset digital infrastructure water usage.
  • – Transparency in reporting water usage and replenishment by digital infrastructure organizations.
| N/A | +| Total water use in supply chain (m 3 ) |

Total water consumed in a digital infrastructure's value chain. This concept is under development and is analogous to upstream scope 3 emissions.

|
  • – Tracking of water consumption across the value chain supplying materials, equipment and services to digital infrastructure.
  • – It is recommended to disclosure water usage data of vendors through environmental product disclosures (EPDs).
| N/A | + +#### 7.2.4 Key metrics of category 4 – waste generation + +The key metrics of waste generation are listed in Table 4. + +**Table 4 – The key metrics of waste generation** + +| Key metric | Description | Application | Reference | +|------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------| +| Waste generated – total waste, e-waste, and end-of-life battery (metric ton) |

The weight of each kind of material, such as total, electronic equipment and battery, generated in the digital infrastructure.

Measurement should start from construction and continue through the digital infrastructure's end of life. Similar to carbon emissions, waste can be measured as direct waste but also waste generated within the digital infrastructure supply chain.

|
  • – Quantification of an organization's waste-related impacts on the environment, by reducing the overall electronic and battery waste generated.
  • – Improvement of industry reporting, by adding indirect waste generation to track supply chain.
| N/A | +| Waste diversion rate – total waste, e-waste and end-of-life battery |

The total weight of waste recycled, such as total, electronic equipment and battery, divided by the total weight of waste generated at a digital infrastructure site.

The waste can be diverted from landfills through circular methodologies including, but not limited to reuse, re-manufacturing, and recycling.

|
  • – Benchmarking and the monitoring of programme improvements toward 100% ratio as part of a zero-waste goal.
  • – Promotion of recycling for end-of-life servers and batteries instead of diverted from landfills.
  • – Reduction of demand for mined minerals through the emerging recyclability of critical materials (e.g., lithium, cobalt and nickel) from li-ion batteries in uninterrupted power supply (UPS) applications.
| N/A | + +#### 7.2.5 Key metrics of category 5 – local ecosystem impacts + +The key metrics of local ecosystem impacts are listed in Table 5. + +**Table 5 – The key metrics of local ecosystem impacts** + +| Key metric | Description | Application | Reference | +|-------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------| +| Land – total land use (m 2 ) |

Total direct land area consumed to operate a digital infrastructure. Land use includes the following areas:

  • – Physical digital infrastructure building(s).
  • – Facilities associated with digital infrastructure, such as outdoor power and cooling equipment, modules and parking lots.
  • – Vegetation-cleared areas for drainage, setback or buffer requirements.

If the digital infrastructure is located on a campus or industrial site with other activities, it is required to assign the appropriate proportion of land to the digital infrastructure for this metric.

|
  • – Reporting of direct land usage by digital infrastructure operators, similar to scope 1 GHG emissions.
  • – Prediction and planning of land use during the design phase to minimize impact on local ecosystems, such as re-purposing brownfield sites or avoidance of environmental degradation in greenfield.
  • – Emphasis on careful site selection and land protection during construction.
| N/A | +| Land-use power intensity (kW/m 2 ) |

The ratio of digital equipment power deployment to the total land used by the digital infrastructure.

Higher values mean better use of the land or less land use.

|
  • – Measuring land usage effectiveness from the design phase.
  • – Optimization of land use by building multi-storey instead of one-storey, deploying high-density racks instead of low-density racks, etc.
| N/A | +| Outdoor noise – dB(A) |

The sound level measured at the digital infrastructure (emitter) property line.

These values can be estimated during the digital infrastructure design phase.

|
  • – Identification of compliance with local noise ordinances.
  • – Consideration of noise-reduction approaches during the design phase, such as low-noise HVAC and genset solutions, and sound-mitigating systems (e.g., acoustic shrouds, louvers and silencers).
| N/A | +| Mean species abundance (MSA) density (MSA/km 2 ) |

This metric indicates the impact on local species by a digital infrastructure in units of mean species abundance per square kilometre.

This metric has been developed as part of a biodiversity footprint methodology to support GBS but is not yet standardized.

|
  • – Providing transparency on a digital infrastructure's impact on species and assessing the effectiveness of species protection plans across its whole lifecycle.
| [b-CDC Biodiversité] and [b-Berger] | + +#### 7.2.6 Key metrics of category 6 – enablement + +The key metrics of enablement are listed in Table 6. + +**Table 6 – The key metrics of enablement** + +| Key metric | Description | Application | Reference | +|-------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------| +| Total enabling GHG emission reduction (mtCO 2 e) |

Total indirect GHG emission reduced by operating digital infrastructure.

The indirect GHG emission should come from the vertical industries and public sectors. The main pathways of indirect GHG emission reduction include substituting offline travel, improving equipment efficiency, virtualizing equipment or devices and introducing renewable energy. The methodology for determining this metric should be published.

|
  • – Quantification of the enablement impact of digital infrastructure.
  • – Assessment of the effectiveness of digital infrastructure plans to indirectly reduce GHG emissions in vertical industries.
| [ITU-T L.1400] and [ITU-T L.1480] | +| Enablement factor (ratio) |

Total enabling GHG emission reduction divided by the total GHG emissions of digital infrastructure, including GHG emissions of scopes 1, 2 and 3.

The enabling GHG emissions should come from the vertical industries and public sectors. When the metric is greater than 1, the digital infrastructure is considered to have a positive impact on reducing GHG emissions. However, when the metric is less than or equal to 1, the digital infrastructure may lead to an overall increase in societal carbon emissions.

|
  • – Determination of whether digital infrastructure contributes to GHG emission reduction, by quantifying its general impact on GHG emissions in society.
  • – Assessment of the extent of digital infrastructure's positive impact on GHG emissions.
| [ITU-T L.1400] and [ITU-T L.1480] | + +#### 7.2.7 Other considerations on sustainability + +Other metrics can be considered to indicate the sustainability of the digital infrastructures. For example, the utilization rate of a digital infrastructure facility, including floor space, rack space and power and cooling system capacities, can be internally tracked to drive improvements. These metrics track and make transparent how efficiently a digital infrastructure is used. In another words, the more an existing digital infrastructure is utilized, the longer digital infrastructure expansion is delayed, lowering overall scope 3 emissions, waste generation, etc. + +Although this is a straightforward concept, the digital infrastructure industry does not always perform well in this area. Some examples include under-utilized assets and stranded digital infrastructure + +capacity or disproportionately used capacity (i.e., run out of space before running out of power and cooling, or vice versa). + +# 8 Key metrics for reporting in digital infrastructure + +This clause details the specific metrics within each category and how they map to the stages of maturity. The selected metrics are considered based on the following seven criteria: + +- Relevance and importance to digital infrastructures. +- Reflecting the impact on the environment, directly or indirectly. +- Standardized and quantifiable for benchmarking and alignment. +- Actionable (can easily be translated into actions to make improvements). +- Applicable to all geographic environments (regions, countries, etc.). +- Compliance with regulations - voluntary or mandatory. +- Eligibility for green capital. + +Digital infrastructure operators should use these metrics to set targets and show progress (e.g., year over year). These metrics should be collected, measured or calculated based on multiple data points during a reporting period (12-month rolling). + +As a result of following these criteria, Table 7 shows several key metrics identified for digital infrastructure operators to report on environmental sustainability in a holistic way. + +**Table 7 – The key metrics for reporting environmental sustainability** + +| Metric categories | Key metrics | Units | Reporting stages | | | +|----------------------|------------------------------------------------|--------------------------|------------------|----------|---------| +| | | | Beginning | Advanced | Leading | +| Energy | Total energy consumption | kWh | √ | √ | √ | +| | PUE | Ratio | √ | √ | √ | +| | Total renewable energy consumption | kWh | | √ | √ | +| | REF | Ratio | | | √ | +| | ERF | Ratio | | | √ | +| GHG emissions | Scope 1 | | | | | +| | GHG emissions | mtCO 2 e | √ | √ | √ | +| | Scope 2 | | | | | +| | GHG emissions | mtCO 2 e | √ | √ | √ | +| | Scope 3 | | | | | +| | GHG emissions | | | | √ | +| | CUE | kg CO 2 e/kWh | | √ | √ | +| | Total carbon offsets | mtCO 2 e | | √ | √ | +| | Hourly renewable supply & consumption matching | Ratio | | | √ | +| Water | Total site water usage | m 3 | √ | √ | √ | +| | WUE | m 3 /MWh | | √ | √ | +| | Total water use in supply chain | m 3 | | | √ | +| | Water replenishment | m 3 | | | √ | + +**Table 7 – The key metrics for reporting environmental sustainability** + +| Metric categories | Key metrics | Units | Reporting stages | | | +|-------------------|---------------------------------------|---------------------|------------------|----------|---------| +| | | | Beginning | Advanced | Leading | +| Waste | Waste generated | | | | | +| | Total waste | ton | | | √ | +| | E-waste | ton | | √ | √ | +| | End-of-life battery | ton | | √ | √ | +| | Waste diversion/Recycling rate | | | | | +| | Total waste | Ratio | | | √ | +| | E-waste | Ratio | | √ | √ | +| | End-of-life battery | Ratio | | √ | √ | +| Ecosystem | Land | | | | | +| | Total land use | m 2 | | √ | √ | +| | Land-use power intensity | kW/m 2 | | √ | √ | +| | Outdoor noise | db(A) | | | √ | +| | MSA | MSA/km 2 | | | √ | +| Enablement | Total enabling GHG emission reduction | mtCO 2 e | √ | √ | √ | +| | Enablement factor | Ratio | | √ | √ | + +# 9 Setting targets for digital infrastructures + +There are emerging regulations (voluntary or mandatory) on metric targets in some regions of the world, to drive the progress of digital infrastructure environmental sustainability. Some standards development organizations (SDOs) have published time-based and self-regulated target values for several key metrics (e.g., PUE, renewable energy use percentage and WUE) through climate neutral policies or mandatory national codes or directives, which stipulate the grades and maximum allowable values for the key metrics. These regulations could be used increasingly as a reference by more regions in the future. + +In order to comply with the regulations, key metrics are identified along with published industry-based target values for each metric. The following five criteria are applied, to determine which of the key metrics described in Table 7 could have target values that apply to all digital infrastructures: + +- Regulations are forthcoming. +- Measurement approaches have been clearly defined. +- Measurement as a ratio or normalized value, not an absolute value. +- Not heavily dependent on geography. +- Not heavily dependent on local jurisdictions (outdoor noise level depends on local noise ordinance). + +Appendix I provides an example of setting metric targets for digital infrastructures. + +# **10 Implementation of digital infrastructure KPIs for environmental sustainability** + +Before a company can set goals or embed ESG into its business strategy and operations, it should decide on how to measure and report on the metrics. Determining which environmental sustainability metrics a digital infrastructure business should track is one of the most important issues it faces. Digital infrastructure operators are facing mounting pressure from investors, regulators, shareholders, customers and employees to provide greater transparency on the reporting of their digital infrastructure environmental impact. Metrics-driven transparency can add value internally by driving sustainability improvements, and externally by increasing stakeholder confidence (e.g., shareholders) and competitiveness. + +Not all digital infrastructure companies are at the same place in their journey. This Recommendation outlines key metrics across three reporting stages: beginning, advanced and leading. + +The beginning stage represents basic reporting for energy, water use and GHG emissions. In essence, these are the core metrics required for every digital infrastructure. The advanced stage adds more detailed metrics for energy, water and GHG emissions, and introduces two new categories including waste and local ecosystem. The leading stage adds even more detailed metrics to the existing categories. + +Digital infrastructure operators can take advantage of the proposed standardized metrics to develop their own list according to where they are in their sustainability journey. + +They can then set reasonable metric targets according to industry target values. + +Digital infrastructure operators shall collect or measure multiple data points during a reporting period (twelve-month rolling) to calculate the metric values. This requires that operators place meters at the right locations for measurement and take advantage of modern digital tools on the market, such as resource advisor and data centre infrastructure management (DCIM). Digital infrastructure operators can then consult frameworks and standards for guidance to report and certify their progress towards their goals, year over year. + +## Appendix I + +## An example of setting metric targets for digital infrastructures + +(This appendix does not form an integral part of this Recommendation.) + +There are emerging regulations (voluntary or mandatory) on metric targets in some regions of the world to drive the progress of digital infrastructure environmental sustainability. For example, the European Data Centre Association (EUDCA) published time-based and self-regulated target values for several key metrics (e.g., PUE, renewable energy use percentage and WUE) through the Climate Neutral Data Centre Pact (CNDCP), while China published a mandatory national code – GB 40879 – 2021, which stipulates the grades and maximum allowable values for PUE. These regulations could be used increasingly as a reference by more regions in the future. + +Applying the five criteria presented in clause 9, the following four key metrics are identified: + +- PUE – The ratio of a digital infrastructure's total energy consumption to IT energy consumption. +- REF – The ratio of renewable energy owned and controlled by a digital infrastructure organization to the digital infrastructure's total energy consumption. +- CUE – The sum of digital infrastructure's annual scope 1 and market-based scope 2 carbon emissions divided by the IT energy consumption with the unit of kg CO2e/kWh. +- WUE – The on-site digital infrastructure water consumption divided by the IT energy consumption with the unit of m3/MWh. + +As the values for each metric vary significantly depending on many factors, including digital infrastructure size, redundancy level, location, load ratio, electricity emission factor and value chain activities, surveys, studies, regulations and industry players were relied on to provide published industry target values. + +Table I.1 summarizes an example of the best-in-class or ideal values and industry target values for these key metrics. + +**Table I.1 – Target values for the four key metrics** + +| Key metrics | Reference | Best-in-class value | Industry target value | +|-------------|-------------------|------------------------------|-----------------------------------| +| PUE | [ISO/IEC 30134-2] | 1.1(75%-85% load ratio) | 1.2-1.3 (75%-85% load ratio) | +| REF | [ISO/IEC 30134-3] | 1.0 | 0.75-1.0 | +| CUE | [ISO/IEC 30134-8] | 0.0 kg CO 2 e/kWh | 0.0-0.12 kg CO 2 e/kWh | +| WUE | [ISO/IEC 30134-9] | 0.0 m 3 /MWh | 0.3-0.45 m 3 /MWh | + +## Bibliography + +- [b-ITU-T L.1302] Recommendation ITU-T L.1302 (2015), *Assessment of energy efficiency on infrastructure in data centres and telecom centres*. +- [b-ISO 14064-1] ISO 14064-1:2018, Greenhouse gases – Part 1: *Specification with guidance at the organization level for quantification and reporting of greenhouse gas emissions and removals*. +- [b-ISO 14064-2] ISO 14064-2:2019, Greenhouse gases – Part 2: *Specification with guidance at the project level for quantification, monitoring and reporting of greenhouse gas emission reductions or removal enhancements*. +- [b-ETSI EN 305 200 series] ETSI EN 305 200 series (2018), *Access, Terminals, Transmission and Multiplexing (ATTM); Energy management; Operational infrastructures; Global KPIs*. +- [b-ETSI ES 205 200 series] ETSI ES 205 200 series (2022), *Access, Terminals, Transmission and Multiplexing (ATTM); Carbon Intensity Management; Operational infrastructures; Implementation of Global KPIs*. +- [b-ETSI TS 105 200 series] ETSI TS 105 200 series (2019), *Access, Terminals, Transmission and Multiplexing (ATTM); Energy management; Operational infrastructures; Implementation of Global KPIs*. +- [b-Berger] Berger, J., et al. (2018), *Common ground in biodiversity footprint methodologies for the financial sector*. +- [b-CDC Biodiversité] CDC Biodiversité is a direct subsidiary of the Caisse des Dépôts (CDC, the French largest public financial institution). +- [b-ETSI Mag] Enjoy the *ETSI Magazine* (2023), *Sustainability*. +- [b-GHG Scope 2] GHG Protocol Scope 2 Guidance (2015). +[https://ghgprotocol.org/sites/default/files/ghgp/standards/Scope%20%20Guidance\\_Final\\_0.pdf](https://ghgprotocol.org/sites/default/files/ghgp/standards/Scope%20%20Guidance_Final_0.pdf) + +- [b-Schneider 2023] Schneider Electric (2023), *Guide to environmental sustainability metrics for data centers*. + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.156-201803-I_PDF-E/14a22f23ced8ba1d63ece69861dbaacc_img.jpg b/marked/L/T-REC-L.156-201803-I_PDF-E/14a22f23ced8ba1d63ece69861dbaacc_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..827609df9ad8667ae079f875841506349f063390 --- /dev/null +++ b/marked/L/T-REC-L.156-201803-I_PDF-E/14a22f23ced8ba1d63ece69861dbaacc_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:c0d2afb537db9f3588854962a991eb1178220b2bbb8ff3cea6712979a53a864b +size 4107 diff --git a/marked/L/T-REC-L.156-201803-I_PDF-E/raw.md b/marked/L/T-REC-L.156-201803-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..c3519f8750d3841cec0ab3bfe73b0306673fba28 --- /dev/null +++ b/marked/L/T-REC-L.156-201803-I_PDF-E/raw.md @@ -0,0 +1,386 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.156** + +(03/2018) + +SERIES L: ENVIRONMENT AND ICTS, CLIMATE +CHANGE, E-WASTE, ENERGY EFFICIENCY; +CONSTRUCTION, INSTALLATION AND PROTECTION +OF CABLES AND OTHER ELEMENTS OF OUTSIDE +PLANT + +Optical fibre cables – Guidance and installation technique + +# --- **Air-assisted installation of optical fibre cables** + +Recommendation ITU-T L.156 + +## ITU-T L-SERIES RECOMMENDATIONS + +## ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT + +| | | +|--------------------------------------------------------|--------------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node elements (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +## Recommendation ITU-T L.156 + +# Air-assisted installation of optical fibre cables + +## Summary + +Recommendation ITU-T L.156 describes air-assisted methods for installation of optical fibre cables in ducts. These methods can be used to install microcables into microducts, or larger cables into ducts or conduits. Installing conditions and equipment required should be different in each case. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|------------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.156/L.57 | 2003-05-14 | 6 | 11.1002/1000/6321 | +| 2.0 | ITU-T L.156 | 2018-03-16 | 15 | 11.1002/1000/13566 | + +## Keywords + +Air-assisted installation, air cooler, blowing, blown-in element, blown installation, cable insertion, coefficient of friction, compressor, crash test, duct, leakage piston, microcable, microduct, microelement, micro fibre unit, optical fibre cable, shuttle. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2018 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|----------------------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 1 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 2 | +| 6 Installation of jacketed cables in ducts ..... | 2 | +| 6.1 Considerations when installing cable ..... | 2 | +| 6.2 Variants of air-assisted installation ..... | 3 | +| 6.3 Operations..... | 4 | +| 7 Installation of microcables in microducts..... | 5 | +| Appendix I – Indian experience: Installation of optical fibre cables by air blowing method.. | 6 | +| I.1 Products required for air-assisted installation of OFC ..... | 6 | +| I.2 Duct ..... | 6 | +| I.3 Air-blowing machine..... | 6 | +| I.4 Advantages of air-assisted installation of OFC ..... | 6 | +| I.5 Method to measure co-efficient of friction..... | 7 | +| Bibliography..... | 8 | + +## Introduction + +Air-assisted installation is based on forcing a continuous high-speed airflow along the cable with an air source. The force of the moving air pushes the cable and makes it advance forward at a typical speed supported by the equipment. + +Generally, the tensile load on the cable is an order of magnitude lower than the typical force involved with other installation methods, like pulling techniques, thus reducing installation hazards. Additionally, with this technique, bends in duct runs have somewhat less effect than with pulling techniques, so that installation speed increases and longer lengths of cable can be installed. Cables are installed virtually without stress, leaving the cable effectively relaxed in the duct upon completion of the installation. + +There are several variants of air-assisted installation: with/without a piston at the front end of the cable, or with a leaking piston. For variants without a piston, there is no pulling force at the front end of the cable; airflow exerts a distributed force along the entire cable. In addition, the connection to a pulling cord is not needed. + +# Air-assisted installation of optical fibre cables + +## 1 Scope + +This Recommendation describes air-assisted methods for installation of optical fibre cables in ducts. These methods can be used to install microcables into microducts, or larger cables into ducts or conduits. Installing conditions and equipment required should be different in each case. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[IEC 60794-5-10] IEC 60794-5-10 (2014) *Optical fibre cables – Part 5-10: Family specification – Outdoor microduct optical fibre cables, microducts and protected microducts for installation by blowing.* + +[IEC 60794-5-20] IEC 60794-5-20, *Optical fibre cables – Part 5-20: Family specification – Outdoor microduct fibre units, microducts and protected microducts for installation by blowing.* + +# 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 blown-in element** [b-ITU-T L.108]: A blown-in element consists of optical fibre(s), sheath and other materials and can be inserted into the microduct by continuous high-speed airflow force. Some of the characteristics of this element are described in clause 7.2 of [ITU-T L.108]. + +**3.1.2 microcable** [b-ITU-T L.162]: An optical fibre cable that is suitable for installation into a subducting microduct. + +**3.1.3 microduct** [b-ITU-T L.108]: A small, flexible tube with enough wall thickness to provide the mechanical protection required by the application, with its outer and inner diameter defined according to the dimension and the condition of the existing duct and the diameter of the microcable. + +**3.1.4 micro fibre unit** [b-ITU-T L.108]: This is a group of fibres (with a count starting at one) that can be installed in a microduct with the blowing technique. + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 cable insertion machine:** The main component of a blowing machine which pushes the cable into the duct with the help of compressed air. + +**3.2.2 leaking piston/open piston:** A piston which allows the air stream to flow through its centre bore or other ports and exerts a low pulling force at the front end of the cable. + +**3.2.3 piston:** A cylindrical part attached to the lead end of the cable, relatively tightly fitting and moving within A duct forced by compressed air. + +**3.2.4 shuttle:** An alternative term for piston. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +HDPE High Density Polyethylene + +OFC Optical Fibre Cable + +# **5 Conventions** + +None. + +# **6 Installation of jacketed cables in ducts** + +## **6.1 Considerations when installing cable** + +### **6.1.1 Cable duct** + +The combination of duct parameters and materials, critical in determining the installation requirements of specific cable designs when using air-assisted techniques (e.g., air tightness, circular shape, friction coefficient, wall thickness, pressure rating of duct, etc.), should be determined by prior testing. Maximum duct inner diameter depends on the type of machine used. See [IEC 60794-5-10] and [IEC 60794-5-20] for details of tests and criteria. + +### **6.1.2 Cable** + +The bounds on maximum and minimum duct inner diameter, and criteria such as noncircularity, compression and obstructions are important for correct installation of cable. + +Maximum installation length is influenced by the stiffness and weight of the cable. A very flexible cable can only be pushed with a low pushing force and it might be necessary to use an additional element at the front end of the cable, like an open shuttle, which allows the air stream to flow through its centre bore and exert a low pulling force at the front end of the cable. This element might also be necessary when the diameter of the cable is very small compared with the internal diameter of the duct. + +When using a piston at the front end of the cable, a pulling force is exerted on the cable. In this case, maximum cable stress, which depends on the cable design, should not be exceeded. + +Cable sheath friction coefficient and friction properties of the duct liner (low enough) are critical. It should be as low as possible. It could be influenced by the selection of the cable coating and duct characteristics. See [b-IEC TR 62470] for guidance on appropriate tests. + +If necessary, the use of the appropriate lubricant is an important factor to obtain an optimum performance. + +### **6.1.3 Cable route** + +Very tight bends in the cable route should be avoided because maximum installation length depends on the number of bends, their location in the route, the shape, gradient of the cable route, etc. Usually, the straighter the duct, the longer the permitted installation length. + +Prior to blowing, the cable route should be "proved" to establish that the duct is clean and open, sufficiently round, and will allow passage of the cable or unit and any piston, if used. This can be accomplished by blowing a piston, ball or plug of appropriate size through the duct (see clause 6.3.1). + +#### **6.1.4 Compressed air** + +High-speed airflow that moves the cable into the duct is normally generated by a compressor on site. The maximum pressure of the compressor depends on the type of equipment used. Typically, this pressure might be approximately 10 to 12 bar. Flow rate at the compressor output depends on the type of equipment and also on the internal diameter of the duct. Usually, the smaller the duct diameter, the lower the airflow rate and also the shorter the installation length for a specific cable design. + +Compressed-air temperature has a great influence on the relevant parameters. At high temperatures, the material used in the cable jacket and duct begins to soften. This increases the friction between cable and duct, causing a reduction in the system performance. For ambient temperatures exceeding 30°C, it is highly recommended to use an air cooler inserted between the compressor and the cable insertion machine. + +### **6.1.5 Cable insertion machine** + +A cable insertion machine consists of a mechanical device that applies a force on the cable and controls its speed into the duct, together with the air-blowing nozzle. The mechanical element can be driven by an air or hydraulic motor with a manual and automatic run-stop device. This element is divided into two construction principles: pushing of the cable by a rubber block caterpillar drive belt or pushing by a notched wheel drive. + +## **6.2 Variants of air-assisted installation** + +The choice of method, described in this clause, depends on several factors: type of cable (diameter, weight, stiffness), duct diameter, shape of the route (number of bends, location of the bends, gradient) and the equipment to be used. In the same manner, the installed lengths and laying speed depend on all of these factors. In all variants, the cable insertion machine may be used. + +### **6.2.1 Installation method with a piston at the front end of the cable** + +In this method, a piston is attached at the front end of the cable. It transfers a defined pulling force to the cable which should not exceed the allowed tensile load. The piston exerts only a fraction of the maximum permissible pulling force on the cable. + +If the piston gets to an oval section of the duct, it may become stuck. To avoid such a situation, the piston should have flexible cup sleeves or similar. + +It is also possible to use a piston with a smaller diameter than the duct's internal diameter applied at the front end of the cable (also known as a *leaking piston*). It could be an open shuttle, which allows the air stream through its centre bore. In this case, the leaking level affects the level of stress suffered by the cable. + +In all cases of this method, it is very important that the rated tensile strength of the cable is not exceeded. This is accomplished with a combination of the sizing of the duct, the sizing of the piston, the air leaking (leaking piston or shuttle) and the airflow/pressure. + +### **6.2.2 Installation method without piston at the front end of the cable** + +In this method, the cable is inserted into the duct free of pulling force by means of a large and fast flowing air volume. The air streaming through the duct exerts a certain thrust on the cable sheath; this force is caused by friction between air particles and cable sheath. The compressor needs to provide sufficient capacity of air for the installation. + +## 6.3 Operations + +### 6.3.1 Precautions + +When installing a cable using these methods, all precautions considered in other installation methods (reels handling, cables, personal security, cable storage in splice point, etc.), need to be taken into account. + +Additionally, prior to the installation of the cable, the following are recommended: + +- Plan the route and determine the best locations where the blowing-in machines should be placed, in order to achieve an optimum adaptation between the machine and the duct. This installation method allows the use of several blowing machines in series at different points of the same route, to obtain longer installation lengths or to solve complexity problems of the route. It may be possible to achieve installation lengths of 3 km, using only one blowing machine, depending on the characteristics of the route, the type of cable, duct and machine used. +- Check the continuity and integrity of the duct, in order to avoid losses of air pressure which may limit the performance of the system. At the points of discontinuity of the duct, the two duct ends should be joined by suitable duct coupler to ensure no air leakage. +- Check the inside of the duct, in the direction of installation, in order to ensure the absence of obstruction elements inside the duct, like water, dust or even stones. In the same manner, the absence of any flattening along the complete length of the duct should be checked (see clause 6.2.1). +- If required, a liquid lubricant can be added to the duct. To spread the lubricant uniformly along the duct, a sponge pushed by the airflow may be used. In some cases, the pouring of additional lubricant during the installation of the cable could be necessary. +- Clean the cable before inserting it into the cable-insertion machines. +- Take into account that a number of persons may be necessary in the installation process, in order that the following processes can be safely managed: handling the cable reel, handling the blowing machine, inserting the cable into the machine and receiving the cable at the far end. +- When required, the cable may be installed from an intermediate point. In this case, once the first part of the cable has been installed, it is recommended to lay the remaining part of the cable as a figure of eight or push it into a fleeting cage by means of the blowing-in machine. +- The maximum pressure the duct can support should not be exceeded. + +### 6.3.2 Installation process + +Once all precautions detailed in the previous clauses have been taken, and the blowing-in machines have been located in the correct places, the following are recommended: + +- Prepare the front end of the cable. When using the installation method without piston, a lightweight cable guide should be fitted over the cable sheath to ease the movement of the cable around bends and through subduct connectors. When using the installation method with piston, the right cable grips should be prepared; they will be attached at the front end of the cable. +- Prepare the duct in order to adapt the blowing machine to the duct. +- If necessary, fit the cable pushing elements of the blowing machine to the cable diameter. +- Assure that the pushing elements of the blowing machine are set to avoid excessive buckling forces on the cable; a "crash test" should be performed. +- Put the cable into the insertion elements of the machine. +- Introduce the cable into the duct. + +- Fix the cable to the insertion elements of the machine. +- Fix the duct to the blowing machine using an appropriate connector, in order to avoid air losses during the process. +- Start up the compressor and any auxiliary power for the pushing elements and connect it (them) to the blowing machine. + +Start the installation by pushing the cable into the duct to overcome initial friction. After an initial section of cable is inserted, the airflow through the duct will begin dragging the cable deeper inside the duct. + +- At the distant end of the duct, the cable should be received. Care must be taken by operators because the cable may come out quite fast. If the installation process finishes at that point, a remaining length of cable, for cable splicing purposes, should be stored in the usual conditions. +- In case of several blowing machines being used in series, when the cable reaches the second installation point, it is necessary to stop the first machine and to introduce the cable into the second machine and duct, as previously detailed, and fix them to the cable. Afterwards, start up the first machine and then the second one. If any additional blowing machine is being used, proceed as detailed. +- When the cable is installed from an intermediate point, install the first length of the cable in one direction. Once completed, lay the remaining cable as a figure of eight or coil it into the special coiling apparatus by means of the blowing machine. Special care must be taken in order to prevent the cable from becoming dirty. Place the blowing machine in order to allow the installation in the opposite direction and proceed in a similar way as detailed previously. + +# 7 Installation of microcables in microducts + +Similar considerations, as previously detailed, should be taken into account when installing microcables in microducts. In this case, usually the diameter of the cables and ducts will be smaller. The characteristics of the ducts, materials and properties may be different. The blowing machines may also be different but precautions and installation process will be similar to those previously detailed. Further criteria for the installation of microducts and microcables are provided in [IEC60794-5-10] and [IEC 60794-5-20]. + +## Appendix I + +## Indian experience: Installation of optical fibre cables by air blowing method + +(This appendix does not form an integral part of the Recommendation.) + +## I.1 Products required for air-assisted installation of OFC + +The liberalization of telecommunications, the advent of Internet and advances in optical fibre technology and have all led to increased need for efficient, fast and highly reliable methods for the installation of optical fibre cable (OFC). The lower weight of OFCs have led to the development of the air blowing technique for their installation. This technique essentially requires two main products: a duct and an air-blowing machine set. + +### I.2 Duct + +The duct is made of high quality high density polyethylene (HDPE) pipe co-extruded with a special solid polymer lubricant as inner lining or ribbed inside surface. The important characteristics of this type of pipe are: + +- low internal coefficient of friction with the outer sheath of the OFC. Additional lubricant (typically water based) can be used to reduce friction further at the time of blowing. The lubricant material should not react with cable outer sheath and duct materials; +- absence of coil-set; +- bending radius: minimum ten times the outer diameter of the duct; +- installation over wide range of temperature $-5^{\circ}\text{C}$ to $+50^{\circ}\text{C}$ ; +- accurately controlled dimensions to enable leak-proof joints with suitable accessories; +- ability to withstand the air pressure required for OFC installation; +- expected life span typically 50 years for high quality HDPE (e.g., PE80 grade) duct. The lifetime estimate for a high-quality HDPE duct has been based on the pressure test from the standard [b-DIN 8075]. + +### I.3 Air-blowing machine + +The air blowing machine is capable of supplying a moisture-free air jet at pressure through a feed machine that introduces the OFC into the duct. It basically consists of: + +- a compressor, capable of delivering air at 10 bar pressure continuously; +- an air cooler with facility to remove water vapour; +- a cable feed system fitted with a pneumatic/hydraulic motor to feed the cable continuously at a speed of up to 100 m/min. Generally, a speed of about 60 m/min is chosen. + +## I.4 Advantages of air-assisted installation of OFC + +The advantages of the blowing method for OFC installation into the duct are: + +- there is no stress on the OFC, as the inner surface of the duct is ultra-smooth. Typically, the coefficient of friction is less than 0.1 as determined by the method mentioned in the clause I.5. It is a pushing rather than pulling action of the cable; +- it allows a longer installation in a faster and more efficient way. A one-kilometre OFC can be laid in less than 20 min; +- the influence of bends and curves is minimized; +- there are a minimum number of joints in the duct and cable splices; + +- the overall cost of installation and maintenance is reduced; +- future upgrading is facilitated. + +## I.5 Method to measure co-efficient of friction + +This procedure outlines the method employed to determine coefficient of friction between duct inner surface and cable outer sheath as described in [b-TEC/GR/TX/CDS-008/03]. + +The required apparatus consists of an extensometer, a circular test fixture of diameter 750 mm, 25 kg weight, an OFC sample and a pulley wheel. + +- A suitable length of the duct, pre-conditioned at $23 \pm 2^\circ\text{C}$ for 2 hours, to be secured to the test fixture such that the duct sample completes a $450^\circ$ wrap, with one end extending vertically 200 mm towards the floor. +- A suitable length of OFC is inserted into the duct sample. +- The extensometer and the test fixture are aligned and secured from movement. +- The 25 kg tail weight is attached to the OFC extending from the 200 mm vertical extension of the sample such that there is a minimum free travel of 150 mm for the weight. +- The other end of the OFC is attached via a pulley, to the extensometer such that the planes of travel are in no direction diagonal and there is slack remaining in the OFC. +- The extensometer is operated, and the maximum load applied, in lifting the 25 kg weight to a minimum travel of 150 mm is noted. +- Extensometer conditions. +- Load: kg or N; Speed: 500 mm/min; Mode: Tension. + +The coefficient of friction is calculated by the following equation: + +$$\text{Coefficient of friction} = \frac{\ln\left(\frac{T_1}{T_2}\right)}{Q}$$ + +Where: + +$T_1$ = Pulling force in kg + +$T_2$ = 25 kg + +$Q$ = Angle of the subtending between $T_1$ and $T_2$ , in radians (i.e., $450^\circ = 7.85398$ radians) + +## Bibliography + +- [b-ITU-T L.100] Recommendation ITU-T L.100/L.10 (2015), *Optical fibre cables for duct and tunnel application.* +- [b-ITU-T L.108] Recommendation ITU-T L.108 (2018), *Optical fibre cable elements for microduct blowing-installation application.* +- [b-ITU-T L.150] Recommendation ITU-T L.150/L.35 (2015), *Installation of optical fibre cables in the access network.* +- [b-ITU-T L.162] Recommendation ITU-T L.162 (2016), *Microduct technology and its applications.* +- [b-ITU-T L.400] Recommendation ITU-T L.400/L.12 (2008), *Optical fibre splices.* +- [b-DIN 8075] DIN 8075 (2011), *Polyethylene (PE) Pipes – PE 80, PE 100 – General Quality Requirements, Testing.* +- [b-IEC 60794-5] IEC 60794-5 (2014), *Optical fibre cables – Part 5: Sectional specification – Microduct cabling for installation by blowing.* +- [b-IEC TR 62470] IEC TR 62470 (2011), *Guidance on techniques for the measurement of the coefficient of friction (COF) between cables and ducts.* +- [b-TEC/GR/TX/CDS-008/03] Telecommunication Engineering Centre, Department of Telecommunication, India, TEC/GR/TX/CDS-008/03/MAR-11 (2011), *Permanently lubricated HDPE telecom Ducts for use as underground optical fibre cable conduits.* + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet 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+|--------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node elements (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000–L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200–L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300–L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400–L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500–L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600–L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700–L.1799 | + +For further details, please refer to the list of ITU-T Recommendations. + +## Recommendation ITU-T L.1620 + +# Guide to circular cities + +## Summary + +Recommendation ITU-T L.1620 contains a circular city implementation framework that is designed to improve circularity in cities and support stakeholders in implementing circular actions. The framework consists of a four-step methodology that provides a consistent method for assessing, prioritizing and catalysing different circular actions. Recommendation ITU-T L.1620 has been developed in response to the growing sustainability challenges that cities are facing and the emergence of the circular economy concept and its applicability and extension in the city setting. + +Recommendation ITU-T L.1620 starts with an assessment of the main developmental and sustainability challenges that cities are facing and the ways in which the concept of circular economy can be extended beyond the economic sphere and be applied to different city assets. + +Recommendation ITU-T L.1620 further defines key components of the circular city implementation framework. These components include: city assets and products (i.e., infrastructure, resources, as well as goods and services available for urban use); circular city actions (i.e., outcome-oriented actions that can be applied to city assets and products); circular city outputs (i.e., the outputs of circular city actions applied to city assets and products); and circular city enablers (i.e., complementary activities that support or accelerate implementation of circular city actions). Each of these components have different qualities and potential for facilitating circularity in cities. Interactions between these components form the basis of the circular city implementation framework. + +Finally, Recommendation ITU-T L.1620 explains the circular city implementation framework. This framework utilizes four different steps to assist city stakeholders in enacting circular actions: 1) establish a baseline for circularity; 2) determine the potential of circularity in different assets and prioritize circular actions based on the availability resources; 3) apply city enablers to catalyse different circular actions; 4) evaluate the impacts of these actions. + +Cities are invited to use Recommendation ITU-T L.1620 to identify a course of action to improve circularity. Recommendation ITU-T L.1620 also includes practical recommendations for preparing circular city actions and their implementation. Recommendation ITU-T L.1620 is complemented by 17 case studies that illustrate the application of the circularity concept based on experiences from cities around the world. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.1620 | 2022-08-13 | 5 | 11.1002/1000/15034 | + +## Keywords + +Circular cities, framework, sustainability. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2023 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 1 | +| 4 Abbreviations and acronyms..... | 2 | +| 5 Conventions ..... | 2 | +| 6 Concept of circular cities ..... | 2 | +| 6.1 Challenges facing cities ..... | 2 | +| 6.2 Moving from a circular economy to a circular city..... | 3 | +| 6.3 Definitions of circular economy ..... | 3 | +| 7 Circular cities ..... | 4 | +| 7.1 City assets and products ..... | 4 | +| 7.2 Circular city actions..... | 6 | +| 7.3 Circular city outputs ..... | 7 | +| 8 Circular city implementation framework..... | 10 | +| 9 Conclusions and recommendations..... | 18 | +| Bibliography ..... | 21 | + +## Introduction + +The way physical goods are produced and consumed remains largely linear: goods are manufactured from raw materials, sold, used (consumed) and then mostly disposed of as waste. At the same time, the sheer quantity of physical goods far outweighs our actual needs, with most consumer products not in use over 90% of the time – and some purchased solely for single use. + +This linear model has been successful in providing affordable goods, services and resources to consumers and material welfare. However, this linear model of production and consumption is material- and energy-intensive; it relies on the principle of economies of scale to produce large amounts of goods at minimal cost, typically builds on more complex and international supply chains and creates large amounts of waste, much of which is not only avoidable, but potentially valuable. This model of production and management of goods, services and resources encourages short-term consumption, creates a range of negative externalities and is leading the planet to a potentially unsustainable future. In this context, the concept of a circular economy has recently emerged as a vision for how to gradually move away from this linear model to one that, by using resources better, is not only more sustainable, but also creates a range of new opportunities for inclusive economic growth. + +The circularity concept can be extended beyond the sphere of economy. Cities are home to a staggering amount and variety of assets and resources that can not only be produced, but also used much more efficiently and sustainably. The efficiency of each item can be improved by applying circular design, resulting in positive social, economic and environmental impacts on a much larger scale. Transitioning to a circular economy will also support city leaders in reaching the Sustainable Development Goals and other global climate objectives. + +Promoting circularity in cities is one of the strategic topics of the United for Smart Sustainable Cities [b-U4SSC] initiative, which brings together 17 UN agencies with the International Telecommunication Union (ITU), United Nations Economic Commission for Europe (UNECE) and UN-Habitat serving as the secretariat. The key performance indicators (KPIs) of U4SSC are among the most effective tools for evaluating circularity in cities. The KPIs are developed based on [b-ITU-T Y.4903]. These indicators support the efforts of cities to evaluate their smartness and sustainability performance. The KPIs were endorsed by the UNECE Intergovernmental Committee on Urban Development, Housing and Land Management (CUDHLM), as well as the ITU-T Study Group 5, *Environment, climate change and circular economy*, which is a global expert group under ITU that develops standards on sustainable and circular cities. + +This Recommendation, which was developed within the U4SSC initiative, will be very useful for cities to implement circular activities and to promote circularity and urban sustainability. + +# Guide to circular cities + +# 1 Scope + +This Recommendation establishes a circular city implementation framework that is designed to improve circularity in cities and support stakeholders in implementing circular actions. The framework consists of a four-step methodology that provides a consistent and scientific method to assess, prioritize, apply and catalyse different circular actions in the city setting. This Recommendation introduces the concept of city assets and products (i.e., city infrastructure, resources, services etc.), circular city actions (which can be applied to assets and products), circular city output (i.e., the results of applying circular actions to city assets and products) and circular city enablers (i.e., complementary actions that support the implementation of circular city actions). The Recommendation helps cities to identify a clear course of action to improve sustainability and achieve Sustainable Development Goal (SDG) 11, *Sustainable cities and communities*, and the related targets. + +This Recommendation has been developed in response to the growing sustainability challenges that cities are facing and the emergence of the circular economy concept and its applicability and extension in the city setting. This Recommendation was developed based on the United for Smart Sustainable Cities (U4SSC) initiative deliverable of the same name [b-U4SSC GCC]. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +None. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 greenhouse gas** [b-ITU-T L.1430]: Gaseous constituent of the atmosphere, both natural and anthropogenic, that absorbs and emits radiation at specific wavelengths within the spectrum of infrared radiation emitted by the Earth's surface, the atmosphere, and clouds. + +NOTE – GHGs include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6) and additionally nitrogen trifluoride (NF3). + +**3.1.2 incineration** [b-ISO/IEC 29142-3]: Disposal method that involves combustion of waste material converting it into heat, gas, steam, and ash but not including smelting. + +**3.1.3 landfill** [b-ISO 472]: Waste disposal site for the deposit of waste onto or into land under controlled or regulated conditions. + +### 3.2 Terms defined in this Recommendation + +None. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|--------|---------------------------------------------------------------------| +| ICT | Information and Communication Technology | +| KPI | Key Performance Indicator | +| NGO | Non-Governmental Organization | +| PESTEL | Political, Economic, Social, Technological, Environmental and Legal | +| PPP | Public-Private Partnership | +| PPPP | Public-Private-People Partnership | +| R&D | Research and Development | +| SDG | Sustainable Development Goal | +| SME | Small and Medium-sized Enterprise | + +# 5 Conventions + +None. + +# 6 Concept of circular cities + +## 6.1 Challenges facing cities + +More than half the world's population now lives in urban areas. In 2016, an estimated 54.5% of the human population lived in urban settlements, and that figure is expected to rise to 60% by 2030. These urban areas consume 75% of natural resources, produce between 60% and 80% of global greenhouse gas emissions, and generate 50% of all waste. + +The number of cities with at least 1 million inhabitants was estimated to be 512 in 2016. This number is projected to reach 662 by 2030. In the same year, there were 31 "megacities", that is, cities with more than 10 million inhabitants. The number of megacities is expected to reach 41 by 2030 [b-UNDESA]. Hence, cities play a crucial role in driving sustainability in production and consumption of goods and services. + +Cities are dense and highly congested physical spaces that are prone to a myriad of challenges such as population growth, urban sprawl, climate change, environmental degradation and fiscal pressures [b-UNECE]. In 2014, more than 80% of cities were located in areas vulnerable to a high risk of mortality or economic losses associated with natural disasters or other environmental challenges. Demographic changes such as: ageing populations; volatile economic growth; unemployment; low-wage, low-skilled jobs; income inequality; social polarization; and segregation are fuelling urban sprawl. Furthermore, the current consumption levels in cities are starting to exceed their economic capacity and biocapacity, ultimately affecting the well-being of all city dwellers. + +Each city has its own unique characteristics and specific social and economic structure, along with the associated challenges. In order to start injecting circularity into different city assets, it is important for cities to assess their current status and identify the appropriate starting points with respect to circularity. The gap between the current state and the intended circular future creates an enormous innovative potential for cities and communities. + +Stakeholders, including the public and private sector, non-governmental organizations (NGOs), civil society and the city dwellers themselves, can work collectively as partners to close this gap. Creating public-private-people partnerships (PPPPs) through the involvement of relevant stakeholders is crucial for circularity. PPPPs enable innovative and alternative financing mechanisms for circular city initiatives. In addition, engaging and working with stakeholders through global platforms such + +as United for Smart Sustainable Cities (U4SSC) offer a reliable way to make the best use of the collective capital of cities and to ensure inclusivity throughout the implementation process. + +## 6.2 Moving from a circular economy to a circular city + +This Recommendation attempts to identify a list of city assets and products that would broaden the circularity concept beyond economy to include different aspects of city management, hence the term "circular city". For example, public spaces in the city (which are not economic products but public assets) may be used for different social activities at different times (i.e., sharing public spaces as a city asset). Similarly, household items may be shared among individuals and households or re-used for different purposes. These examples transcend economic activities and enhance the utilization of city assets beyond them. + +The circularity approach proposed in this Recommendation is meant to increase the efficiency and effectiveness of city assets and products by extending either their own utilization and lifespan or those of their constituents or components. This increase is achieved by applying targeted action items (referred to in this Recommendation as circular action items) on city assets and products, such as sharing, recycling, refurbishment, re-use, replacement and digitization. Action items are a set of specific, discrete, outcome-oriented tasks that can be applied to city assets and products to improve their utilization and lifespan.1 This Recommendation explains the purpose and vision behind a circular economy, while providing an implementation framework on how to establish circularity within the context of cities. + +## 6.3 Definitions of circular economy + +The Recommendation does not provide a new definition for circular economy. Instead, it has compiled a list of existing definitions of circular economy, in order to illustrate the concept. In general, a circular economy is an economic system where products and services are traded in closed loops or cycles. Table 1 lists some of the well-known circular economy definitions and their interpretations. + +**Table 1 – Existing definitions of circular economy** + +| Definition | Source | +|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------| +| A circular economy is restorative and regenerative by design, and aims to keep products, components, and materials at their highest utility and value at all times, while reducing waste streams. A concept that distinguishes between technical and biological cycles, the circular economy is a continuous, positive development cycle. It preserves and enhances natural capital, optimizes resource yields, and minimizes system risks by managing finite stocks and renewable flows, while reducing waste streams. | [b-ITU-T L.1020] | +| Circular economy is the "production and consumption of goods through closed loop material flows that internalize environmental externalities linked to virgin resource extraction and the generation of waste (including pollution)". | [b-Sauvé] | +| Circular economy is an approach that would transform the function of resources in the economy. Waste from factories would become a valuable input to another process – and products could be repaired, re-used or upgraded instead of thrown away. | [b-Preston] | + +1 The action items are explained in detail in clauses 7 and 8. + +**Table 1 – Existing definitions of circular economy** + +| Definition | Source | +|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------| +| Circular economy "refers mainly to physical and material resource aspects of the economy – it focuses on recycling, limiting and re-using the physical inputs to the economy, and using waste as a resource leading to reduced primary resource consumption". | [b-EEA] | +| A circular economy is an alternative to a traditional linear economy (make, use, dispose) in which we keep resources in use for as long as possible, extracting the maximum value from them whilst in use, then recovering and re-using products and materials. | [b-Mitchell] | +| Circular economy is "an industrial system that is restorative or regenerative by intention and design. It replaces the 'end-of-life' concept with restoration, shifts towards the use of renewable energy, eliminates the use of toxic chemicals, which impair re-use, and aims for the elimination of waste through the superior design of materials, products, systems, and, within this, business models". The overall objective is to "enable effective flows of materials, energy, labour and information so that natural and social capital can be rebuilt". | [b-EMacAF 2013a]
[b-EMacAF 2013b]
[b-EMacAF 2015] | +| The circular economy is an economy "where the value of products, materials and resources is maintained in the economy for as long as possible, and the generation of waste minimised". | [b-EC 2015] | + +Circular economy in cities aims to create a sustainable system that allows for the optimal use of city assets and products through re-use, refurbishment, remanufacturing, recycling, etc. This Recommendation explains the concept of circular cities and provides a methodology for the implementation of circular actions at city level, as well as offering good practices and concrete recommendations for promoting circularity in cities. It also demonstrates the positive impacts and challenges of the implementation of circularity concept. + +# 7 Circular cities + +## Components of the circular city implementation framework + +The following four components constitute key components in the circular city implementation framework. They are the necessary components for implementing circularity in cities. + +- City assets and products – encompass various parts of the infrastructure, resources, goods and services available for urban use or consumption. +- Circular actions – specific, outcome-oriented actions that can be applied to city assets and products that include sharing, recycling, refurbishment, re-use, replacement and digitization. +- Circular city outputs –results of application of circular actions to urban assets and products. +- Circular city enablers – various supplementary and complementary items that are used to catalyse and support circular city outputs. + +### 7.1 City assets and products + +Figure 1 presents various city assets and products. They are classified into three categories: city infrastructure; city resources; and city goods and services (as potential inputs to circular action items described in clause 7.2). + +![Figure 1: City assets and products categorization. A hierarchical diagram showing the top-level categories of city assets and products.](cfef993dcc8fb513de79eb1f93cf26ae_img.jpg) + +``` +graph TD + CAP[City assets and products] --> CI[City infrastructure] + CAP --> CR[City resources] + CAP --> CGS[City goods and services] + CI --> B[Buildings] + CI --> PSI[Public spaces and infrastructure] + CI --> DI[Digital infrastructure] + CR --> N[Natural] + CR --> HRO[Human related and owned] + CR --> PSA[Private sector assets] + CR --> W[Waste] + CGS --> MG[Manufactured goods] + CGS --> S[Services] +``` + +L.1620(22) + +Figure 1: City assets and products categorization. A hierarchical diagram showing the top-level categories of city assets and products. + +**Figure 1 – City assets and products categorization** + +Figure 2 further breaks down the three categories hierarchically. + +![Figure 2: City assets and products detailed categorization. A hierarchical diagram breaking down the categories from Figure 1 into more specific sub-categories.](5a4e62bead259c258d069fd3663ea670_img.jpg) + +``` +graph TD + CAP[City assets and products] --> CI[City infrastructure] + CAP --> CR[City resources] + CAP --> CGS[City goods and services] + CI --> B[Buildings] + CI --> PSI[Public spaces and infrastructure] + CI --> DI[Digital infrastructure] + B --> B1[Residential, community buildings] + B --> B2[Commercial, corporate buildings] + B --> B3["Public sector buildings (Educ., Health, culture heritage, etc.)"] + PSI --> PSI1[Communications infrastructure] + PSI --> PSI2[Water infrastructure] + PSI --> PSI3[Energy infrastructure] + PSI --> PSI4[Mobility infrastructure] + PSI --> PSI5[Green infrastructure] + PSI --> PSI6[Public spaces and other Infra.] + CR --> N[Natural] + CR --> HRO[Human related and owned] + CR --> PSA[Private sector assets] + CR --> W[Waste] + N --> N1[Air] + N --> N2[Water] + N --> N3[Energy] + N --> N4["Land, soil etc."] + N --> N5["Biotic, (Forest, fishery, etc.)"] + HRO --> HRO1[Individual skills] + HRO --> HRO2[Individual and household items] + PSA --> PSA1[Municipal] + PSA --> PSA2[Industrial] + CGS --> MG[Manufactured goods] + CGS --> S[Services] + MG --> MG1[Sector 1] + MG --> MG2[Sector ...] + S --> S1[Sector 1] + S --> S2[Sector ...] +``` + +L.1620(22) + +Figure 2: City assets and products detailed categorization. A hierarchical diagram breaking down the categories from Figure 1 into more specific sub-categories. + +**Figure 2 – City assets and products detailed categorization** + +**City infrastructure:** Buildings, public spaces and infrastructure, as well as the digital infrastructure (see Figure 1). + +- a. *Buildings* provide the essential space for a city to function, such as living and workplaces, storage places for belongings and shelters for the needy. The types of buildings in a city include residences such as apartments and houses, commercial facilities such as offices and shopping malls, and public structures such as hospitals, schools, places of worship, historical sites, accommodation for government and military-related activities, as well as other civic buildings that belong to the public sector. +- b. *Public spaces and infrastructure.* A public space is an urban place that is generally open and accessible to people in a city, which may include public squares, sports fields, and beaches. Infrastructures are connective structures that enable people in a city to get the resources they need (e.g., from the environment) and bring them to the city; or they may enable flows or + +cycles in city [b-City Anatomy]. Infrastructure types include communication, water, energy, mobility (transport), digital and green, specified as follows. + +- *Communication infrastructure* includes telecommunications, radio, television and Internet infrastructure (including analogue and digital transmissions through various physical media such as copper, coaxial, fibre). + - *Water infrastructure* includes supply, sanitation and the management of treated waste and surface waters, including irrigation, drainage and collection. + - *Electrical energy infrastructure* includes generation, transmission and distribution infrastructure for various available energy sources (e.g., fossil fuel power plants, nuclear plants, hydroelectric dams, solar installations, wind farms, bio-energy systems). + - *Mobility infrastructure* includes human and goods transportation and general mobility infrastructure (e.g., roads, airports, railways, ports, promenades, bridges, pavements, footpaths, bicycle paths). + - *Green infrastructure* is composed of natural elements present in the city in a structured manner (e.g., parks, trees, horticultural areas such as gardens). +- c. *Digital infrastructure* includes equipment and services needed to deliver digital services (excluding communications infrastructure), e.g., data centres, information technology and data-processing equipment and systems, cloud computing. + +**City resources.** Resources are stocks or reserves of money, materials, people, or some other asset, which can be drawn on when necessary [b-OED]. + +- a. *Natural resources* are those materials or substances of a place which can be used to sustain life or for economic exploitation [b-OED]. Natural resources include those that are abiotic: air, water, oil, wind resources, natural gas, iron and coal, land and soil; and biotic, such as forests and fisheries. Resources can be broadly classified upon their availability as renewable and non-renewable. They can also be classified as actual and potential, based on their level of development and use. +- b. *Human-related or owned resources* are inherent qualities of individuals such as skills and knowledge. Human-owned resources are various household items, and other materials and goods owned and used by individuals. +- c. *Private sector assets* are tangible assets owned by private sector organizations that are used to produce products in the form of goods and services. Private sector assets include machinery, warehouse items, company cars and various other tangible assets owned and used by private sector organizations. +- d. *Waste* is anything that no longer has a use or purpose and needs to be collected, potentially transported and discarded or disposed of. It includes municipal and industrial waste. Some examples of waste are household rubbish, wastewater, hazardous waste (e.g., containing hazardous chemicals) and radioactive waste (may require special processing and disposal). + +**City goods and services.** City products include all products of economic sectors and industries in the form of goods and services. In general, they can be categorized by different economic sectors or industries (e.g., by SIC – Standard Industrial Classification [b-OSHA]) of a city. + +## 7.2 Circular city actions + +Circular city actions are specific, discrete, outcome-oriented tasks that can be applied to the assets and products shown in Figure 1 to improve their utilization and lifespan. Sharing, recycling, refurbishment, re-use, replacement and digitization have been identified in this Recommendation as potential circular action items. + +**Sharing** is the joint use of city assets and products. + +**Recycling** is the process of converting city assets and products arriving at their end of life into new materials and objects to make them consumable or usable again. What is treated as waste and thrown away as rubbish could potentially be useful again through recycling. Recycling is an alternative to conventional waste disposal (i.e., incineration or landfill) that can save materials and, among other positive environmental impacts, help lower greenhouse gas emissions. It can also reduce energy usage, air pollution (from incineration), and water pollution (from landfill), and so on. + +**Refurbishment** is about restoration of an old city asset or product to bring it to a functional or better condition. Refurbishment is a potential circular action that can be applied to extend the lifespan of city assets and products. + +**Re-use** involves use of a product or material again, with the same or a new function. + +**Replacement** is filling the place of, or providing a substitute for, a city asset or product. Replacement of city assets and products or their components may enhance their circularity potential by extending their lifespan and utilization. + +**Digitization** is "taking analogue information and encoding it into zeroes and ones so that computers can store, process, and transmit such information" [b-Bloomberg]. Digitization of information about assets and products allows cities to reach more customers, reduce cost and reduce environmental impacts. + +## 7.3 Circular city outputs + +When applying circular action items to a city asset, a circular city output is produced. There are many potential circular city outputs given the large number of city assets and products and the number of circular city actions identified in clauses 7.1 and 7.2. Table 2 provides a template for plotting potential outputs when a circular city action item is applied to an asset or product. The output is inserted into the table cell where circular action item intersects with a city asset or product. + +**Table 2 – Template for defining potential circular city outputs** + +| | | Circular action item | | | | | | | +|-----------------------|----------------------------------|----------------------|-----------|---------------|--------|-------------|--------------|--| +| | | Sharing | Recycling | Refurbishment | Re-use | Replacement | Digitization | | +| City asset or product | Buildings | | | | | | | | +| | Public spaces and infrastructure | | | | | | | | +| | Air | | | | | | | | +| | Water | | | | | | | | +| | Energy | | | | | | | | +| | ... | | | | | | | | + +For instance, the circular action item "re-use" column when applied to a city asset, is completed in the "water" row when water is purified and reused. + +Similarly, the circular action item "sharing" can be applied to the service sector. For example, a day care facility for children could be combined with a facility for senior citizens by placing a day care centre in a nursing home. + +Waste such as bottles, metal, footwear and plastic cups can be separated into compostable and non-compostable. The non-compostable items can then be sold to scrap dealers and the compostable items + +to farmers. This is an example of the application of the recycling and re-using circular action items to city resource "household items". + +The sharing action item can also be applied to public spaces, which can be used with alternating distinct purposes. For example, a public square can be used as a general place for public gatherings and for occasional art events and festivals. + +These examples are given in order to illustrate the concept of circular city outputs. There are many more combinations of circular action items and city assets and products that can be used to generate circular city outputs. + +## 7.4 Circular city enablers + +A circular city enabler is any entity, activity, or initiative that, through its functions, can catalyse and promote circularity in cities. The following are examples of enablers that a city can use to boost its circular city outputs. + +- a. **Circular key performance indicators and their baseline and target values.** Key performance indicators (KPIs) are useful for measuring progress and evaluating outcomes of activities supporting circularity. Indicators to measure city performance have been formulated, some of which measure circularity in cities. Examples of earlier formulated circular city-related KPIs follow. + - i. U4SSC KPIs for smart sustainable cities: The U4SSC has developed the KPIs for smart sustainable cities to evaluate the smartness and sustainability of a city. The KPIs focus on measuring three key city dimensions: economy; environment; and society and culture. They are useful for measuring the impacts of circular city outputs and informing planners to make better design choices. The specific KPIs that could be particularly useful include those for public building sustainability, green spaces, solid-waste collection and treatment and shared vehicles. In addition, each KPI is connected to one or multiple targets of the SDGs, making them the ideal tools for measuring progress towards their achievement. + - ii. The Ellen MacArthur Foundation has undertaken a project called 'The Circularity Indicators Project'. The project provides a methodology and tools to assess the performance of a product or company in the context of a circular economy. The project has published a toolkit and methodology for circularity indicators [b-EMacAF]. + - iii. [b-ISO 37120] helps cities to measure their performance in improving quality of life and sustainability. Some KPIs in [b-ISO 37120] can be utilized in the framework of circular cities (e.g., those related to waste management). + - iv. ITU has developed a series of Recommendations to help cities to assess their sustainability, e.g., [b-ITU-T L.1440] provides guidance on assessing the environmental impacts of ICTs at city level. It takes into consideration multiple factors, including the process of raw material acquisition, production, use and end-of-life treatment of ICTs, which could be extrapolated to assess circularity in cities. + +There are several other circularity indicators developed by different organizations to address various aspects of circularity [b-WBCSD]. Cities can explore these KPIs to determine which one would be the most applicable to their operation depending on their own context. In addition, the implementation framework depicted in this Recommendation is flexible enough to incorporate other specific KPIs that can be formulated by cities themselves for their circularity implementations. Additional KPIs can be included during implementation by a city. + +- b. **Awareness building of circular city initiatives and actions.** The success of circular city initiatives depends largely on the awareness of their stakeholders. The uptake of circular city initiatives is highly dependent on city-wide awareness and their adoptability to their potential + +users. Promoting and explaining their benefits may help to drive cultural and behaviour changes towards embracing circularity. + +- c. **Training and circularity skills enhancement.** Targeted skill enhancement programmes may help in institutionalizing circularity in cities. Academic programmes (e.g., university degrees and courses, related curricula changes) help to enhance circularity skills through formal education. Vocational and professional training programmes could also assist in this regard. Moreover, sharing and disseminating, for example, circularity-related publications, reports and research may also help to further develop circularity-related skills. These programmes help in creating highly skilled human capital for implementing circularity actions at the city level, as well as bridging skills and expertise gaps that have traditionally been a major obstacle towards circular economy. +- d. **Measures to promote trust in circular activities.** Circularity includes circular action items such as sharing being applied to various city assets and products. Sharing may be applied to commercial items or to products (e.g., shared accommodation or ride sharing) and non-commercial items (e.g., sharing of household items on a complementary basis in a city among its inhabitants). In sharing, it is important to introduce trust among city users. Hence, in sharing services, service providers should ensure that they address the concerns of their customers, protect their rights and provide them with reliable and high-quality services to gain their trust. Additionally, it is important for these service providers to ensure the safety and security of shared city assets and products. Over time, addressing issues consistently and reliably builds trust for service providers. +- e. **Urban industrial symbiosis** is a subfield of industrial ecology that takes a collective approach to engage separate industries, in order to gain competitive advantages by facilitating the mutual physical exchange of materials, energy and services [b-Albino]. For instance, waste resulting from one production process can be used as primary inputs (materials or energy) to another. This allows the creation of closed loops within and across industries that in turn enhance circularity in cities. +- f. **Circularity-related strategic planning and policy making.** Holistic circularity strategies and policies led by a city administration can align city stakeholders to a common target and mobilize them for successful implementation. Impact investment and corporate social responsibility initiatives undertaken by the private sector can also catalyse circularity in a city. +- g. **Utilizing procurement as a lever for circularity.** Procurement is a strong lever for emphasizing and enforcing circularity in the public and private sectors. Incentive plans can be used as a tool to avail the supply of circular city assets and products during their procurement (e.g., raw materials, components). +- h. **Financial incentives for boosting circularity.** City administrations and public sector organizations may utilize financial incentives to boost circularity in a city. Monetary (financial) benefits can be offered to consumers and suppliers of circular city outputs, which would encourage their participation in circularity. Financial incentives include, but are not limited to: tax breaks, reductions, exemptions, holidays; lower loan rates, excise taxes, value added tax; impact investment alternatives. +- i. **Public-private partnerships (PPPs) for circularity.** City administrations (public sector organizations) and private sector organizations may collaborate and form partnerships to improve circularity in the city. This approach allows partners to align and unify their goals and share the risks and rewards of implementing circularity actions. +- j. **Research and development (R&D) programmes for circularity.** Circularity provides enormous innovative potential for cities in addressing their sustainability challenges. In some cases, further R&D would be required to turn circularity ideas into reality. Well-designed R&D programmes that target actual city challenges and are led by academia, private and + +public sector organizations may help to overcome various obstacles to implementing circular actions. + +- k. **Circularity regulations.** City administrations can set out various regulations and standards to boost circularity in the city. They may take the form of circularity-related technical standards, product regulations, compliance standards, trade regulations, and waste and safety regulations. Regulations are, in general, ancillary or subordinate to laws. However, they are enforceable and, therefore, constitute a strong lever for circularity. +- l. **National laws and directives.** Law is a system of rules created and enforced through governmental institutions to regulate behaviour. Laws can take the form of legislation, directives, acts of parliament, etc., and they are influenced by the constitution. Laws can potentially be used as an alternative tool to change the behaviour of a society towards embracing circularity (in general, laws are made at the national rather than city level). +- m. **Certifications for circularity.** Cities can leverage existing certifications or create new ones to encourage and incentivize circularity. Certifications rely on well-defined and verifiable standards to measure or optimize performance and allow certified organizations to demonstrate their commitment towards a specific goal (i.e., circularity in this case). Certifications are usually voluntary in nature, rather than mandatory; however, they can provide a competitive advantage for certified organizations. They are an indicator of compliance to well-defined standards or criteria and are usually issued by a credible third party after an independent auditing process. +- n. **Engaging and ensuring participation of stakeholders.** It is important for cities to engage and ensure the participation of all their stakeholders during the formulation and implementation process of circularity initiatives or action items. An inclusive and participatory implementation process would be highly beneficial for maximizing collective city capital. Collaborative platforms that facilitate multi-stakeholder engagements among the public and private sectors, academia, NGOs, civil society and city inhabitants can also be used by cities to ensure broad engagement. +- o. **Circularity-related city innovation ecosystem.** Fostering a robust and productive ecosystem helps to boost circularity in cities. Entrepreneurs can be encouraged and incentivized to establish start-ups for addressing circularity challenges in cities. Accelerators and incubators can also be utilized to support circularity-related small and medium-sized enterprises (SMEs). City circularity challenges drive concrete demand to be met by entrepreneurs and SMEs in the city innovation ecosystem. +- p. **Integrated urban services.** Such urban services will help in realization of circularity in cities. e.g., WMO is developing integrated urban hydrometeorological, climate and environmental services (IUS) [b-WMO] to support safe, healthy, resilient and climate friendly cities. Such services involve combining heterogeneous observation networks, high-resolution forecasts, multi-hazard early warning systems and climate services. They should assist cities in setting and implementing mitigation and adaptation strategies that will enable the management and building of circular cities. + +Assets and products, actions, outputs and enablers are the four components for formulating circular city strategies. Clause 8 details the implementation framework and the necessary steps for achieving circularity in cities. + +# 8 Circular city implementation framework + +This clause describes a four-step circular city implementation framework according to the four components that conclude clause 7.4. + +The framework includes four steps: + +- 1. assessment of current circularity (baselining); + +2. determination of potential for future circularity and prioritization of circularity actions; +3. catalysing circularity; +4. assessment of projected circularity impact. + +Explanations of each of the four steps follow. + +### **Step 1: Assessment of current circularity (establishing a baseline)** + +This step entails conducting a swift baseline audit, which determines the status of a city with respect to its circularity. More specifically, it evaluates the baseline of a city with respect to the following three components: + +- KPIs related to circularity of cities; +- city-level circular initiatives and relevant action items; +- various circular city enablers to assist in implementation. + +Brief explanations of each of these components follow. + +#### **a. Baselining based on existing circular city KPIs** + +Evaluating city performance using KPIs may guide the implementation of the circularity approach; not only does it measure the performance of circular city initiatives, but also it is an effective way to monitor their progress. Some examples of circularity-related KPIs include percentages of wastewater receiving treatment, solid waste recycled, and renewable energy consumed in the city. Cities can further set other circularity KPIs at the sector or industry level, such as percentages of materials and products refurbished, remanufactured, re-used, recycled or shared. Potentially, all circular city outputs described in this Recommendation can be associated with circularity KPIs. + +Table 3 is a template that a city can use to collect the necessary data according to the selected KPIs and evaluate its progress on circularity. + +**Table 3 – Template to data collection for evaluating city circularity using KPIs** + +| City circularity KPI No. | Baseline value (if known) | Target value and timeframe (if known) | Measurement frequency | KPI owner | Comments | +|---------------------------------|----------------------------------|----------------------------------------------|------------------------------|------------------|-----------------| +| KPI 1 | | | | | | +| KPI 2 | | | | | | +| ..... | | | | | | +| KPI N | | | | | | + +#### **b. List of initiatives or action items to promote circularity in cities** + +Cities should prepare a list of their initiatives and actions that promote circularity. Some of these initiatives and actions may be formulated based on the assessment using the circularity KPIs. The list may also include other projects based on the city's overall approach to implementing circularity (e.g., pilot projects). In some cases, there may also be national level initiatives that are being implemented in a city. + +Multiple initiatives and actions can be implemented at the same time to achieve circularity targets. + +Table 4 is a template for preparing a list of circularity initiatives and action. + +**Table 4 – Template for developing a list of city circularity initiatives and actions** + +| City circularity initiative or action item No. | City circularity KPIs (if any) | Brief explanation | Milestones | Owner | Comments | +|-------------------------------------------------------|---------------------------------------|--------------------------|-------------------|--------------|-----------------| +| Initiative or action item 1 | | | | | | +| Initiative or action item 2 | | | | | | +| ..... | | | | | | +| Initiative or action item N | | | | | | + +#### **c. Enablers** + +Circular city enablers are actions and initiatives that can boost circular city output. The utilization of these enablers could elevate the likelihood of success for a city in implementing its circular initiatives or action items. + +Table 5 is a simple template for establishing a baseline and assessing the current status of circular city enablers of a city. + +**Table 5 – Template for assessing circular city enablers** + +| Assessment element | Currently exists | Brief description | Comments | +|---------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------|--------------------------|-----------------| +| Are there awareness programmes for circularity-related initiatives in the city? | | | | +| Are there skill-boosting programmes to enhance and enrich circularity knowledge in the city? | | | | +| Are there existing certification programmes in the city for circularity-related implementations? | | | | +| Is there a vibrant and rich innovation ecosystem in the city to address and implement circularity-related implementations? | | | | +| Are there regulations and laws (including directives, legislation, standards) supporting or impeding circularity-related implementation projects in the city? | | | | +| Are there established trusted intermediaries (or plans in place) for sharing initiatives in the city? | | | | + +**Table 5 – Template for assessing circular city enablers** + +| Assessment element | Currently exists | Brief description | Comments | +|----------------------------------------------------------------------------------------------------------------------------------|--------------------------|--------------------------|-----------------| +| Are there existing circularity-related strategies and policies in the city public and private sectors? | | | | +| Is public procurement utilized as a lever for circularity-related implementation projects? | | | | +| Are there mechanisms in place to ensure the security and safety of shared city assets and products? | | | | +| Are there existing collaborations and partnerships in place among city industrial organizations for circularity implementations? | | | | +| Are there existing skills in place within the public and private sectors to implement circularity? | | | | +| Are there existing PPPs in the city for circularity-related implementation projects? | | | | +| Are there existing R&D programmes and other targeted academic programmes for circularity-related implementation projects? | | | | +| Are the city stakeholders currently aware of circularity initiatives or action items in the city? | | | | +| Are broad stakeholders defined for city circularity initiatives or action items? | | | | +| Are the stakeholders in the city engaged broadly for circularity-related implementations? | | | | +| Is there an established financial framework that can promote city circularity implementation? | | | | +| Are there existing financial incentives in the city for circularity-related implementation projects? | | | | + +## Step 2: Determination of potential for circularity and prioritization of circular city actions + +Following step 1, the city can then formulate its own circularity initiatives and actions. The city can engage a broad range of stakeholders to not only define the city's own circularity priorities and needs but also determine a list of actions to promote circularity for implementation. + +The potential list of circular city outputs (i.e., different combinations of *circular* city action items applied to city assets and products) can assist in identifying a list of potential circularity innovations in the city. Specific city needs and priorities may help to emphasize certain circular city outputs or conversely de-emphasize or eliminate others. Each city may have to go through this exercise based on its own context, aspirations, and goals. This Recommendation defines an output as an individual result of an action taken within the implementation framework with respect to promoting city circularity. + +Another important input to this step is comparison with the benchmarking of successful circularity initiatives or action items of other cities. The city needs to be careful in assessing the applicability of international benchmarks as the context of cities and their aspects may vary significantly. + +In this step, a long list of circularity initiatives or action items can be formulated for implementation. It is recommended that a city utilize its collective capital extensively to come up with various ideas contributing to circularity in its own urban context. + +#### Circularity prioritization approach + +The city might not be equipped to implement the list of circularity actions in its entirety or may lack the requisite resources to do so. In such cases, a prioritization mechanism is highly beneficial. A pragmatic prioritization approach used in this implementation framework has two main criteria: 1) the value, which refers to the projected value of the circular city idea; 2) identification of the projected costs of implementing the selected idea, which is dependent on the city's own context. Each criterion is composed of several subcriteria, which are briefly explained as follows. + +##### i. Value + +- *The degree of alignment with the city circularity vision and strategy* subcriterion refers to the overall fit of circularity actions to an existing circularity vision and strategy of a city (if it exists). +- *The city circularity KPI(s) impact* subcriterion indicates the extent of the contribution of circularity actions to existing circularity KPI(s) in the city. +- *The social impact* subcriterion assesses the impact of the circularity actions on people and communities in the city, including people's lifestyle, culture, participation and engagement, health and well-being, personal freedom and privacy, concerns and aspirations. It is also important to assess whether circularity impacts the entire city or its part. +- *The economic impact* subcriterion assesses the impact of circularity actions on the city economy. Economic impact can be measured by indicators such as the gross revenue, rate of employment, wealth, disposable income, labour-force skills of a city. +- *The environmental impact* subcriterion assesses the impact of circularity actions on the overall environment of a city. Environmental impact captures effects of the circularity action on urban natural environment and resources (e.g., city water, energy, emissions, air, land, waste). + +##### ii. Ease of implementation + +- *The cost of implementation* subcriterion measures the total cost and financial resources required to implement circularity action. +- *The timeframe of implementation* subcriterion refers to the total implementation time of circularity actions. + +- *The implementation risk* subcriterion encapsulates various risks that may potentially arise during the implementation of circularity actions. The following factors may help in assessing various risks. + - *Political, economic, social, technological, environmental and legal (PESTEL) barriers.* This factor captures the PESTEL barriers that exist in the city and may hinder circularity. + - *Complexity.* This factor reflects the complexity of implementing circularity action in terms of number of stakeholders involved, various uncertainties involved in implementation, dependencies and connections to other initiatives or action items in the city, etc. + - *Availability of competence and knowledge for the implementation.* This factor includes the extent to which the circularity can be implemented by harnessing existing knowledge and skills in the city. + - *Health and safety concerns.* This factor entails various concerns and ramifications related to health and safety aspects within the city regarding circularity. + - *Ethical issues.* This factor captures various ethical concerns that may potentially arise during and after the implementation of circularity actions. + +The city can adopt a simple scoring system to determine priorities for various criteria and subcriteria, e.g., of three (low, medium, high) or five levels. The scores can be determined either quantitatively or qualitatively relying on available data and analyses conducted. Having a well-defined prioritization approach helps cities to facilitate prioritization of circularity actions. + +Figure 3 provides an illustration of how to determine the potential and prioritize different circular actions using a simple scoring system. + +![Figure 3 – Evaluation of circular city actions. A scatter plot showing the relationship between Value (Y-axis) and Ease of implementation (X-axis) for various circular actions. The Y-axis ranges from Low to High, and the X-axis ranges from Low to High. Circular actions are plotted as follows: Circular action 1 (High Value, Low Ease), Circular action 2 (High Value, Low-Mid Ease), Circular action 3 (Mid-High Value, High Ease), Circular action 4 (Mid Value, Mid Ease), Circular action 5 (Mid Value, Low Ease), Circular action 6 (Mid Value, High Ease), Circular action 7 (Low-Mid Value, Mid Ease), Circular action 8 (Low Value, High Ease), and Circular action N (Low Value, Low Ease). Ellipses represent the actions, with three dots indicating additional actions between actions 5 and 7.](ebce355620876e10f907f8b71926c112_img.jpg) + +Figure 3 – Evaluation of circular city actions. A scatter plot showing the relationship between Value (Y-axis) and Ease of implementation (X-axis) for various circular actions. The Y-axis ranges from Low to High, and the X-axis ranges from Low to High. Circular actions are plotted as follows: Circular action 1 (High Value, Low Ease), Circular action 2 (High Value, Low-Mid Ease), Circular action 3 (Mid-High Value, High Ease), Circular action 4 (Mid Value, Mid Ease), Circular action 5 (Mid Value, Low Ease), Circular action 6 (Mid Value, High Ease), Circular action 7 (Low-Mid Value, Mid Ease), Circular action 8 (Low Value, High Ease), and Circular action N (Low Value, Low Ease). Ellipses represent the actions, with three dots indicating additional actions between actions 5 and 7. + +L.1620(22) + +**Figure 3 – Evaluation of circular city actions** + +Figure 3 shows how the prioritization approach can be used to facilitate the selection of a subset of circularity actions by applying the two criteria: value; and ease of implementation. City administrators can subsequently shortlist circular city actions that are of high value and easy to implement. Similarly, low-value and relatively difficult to implement circular actions may either be eliminated or given low priority during the implementation process. + +Hence, by the end of step 2, the city will have a concrete list of circularity initiatives and actions for implementation. The city can then elaborate an implementation plan by deciding which circularity initiatives and actions to initiate and evaluate constraints such as resource availability to determine the actual implementation timing. It is also important to minimize implementation risks during the process. + +### **Step 3: Catalysing circularity** + +Some of the enablers previously discussed can be utilized in this step to enhance the effectiveness of selected circularity initiatives or action items. The city can utilize an appropriate mix of enablers to maximize the chance of successfully implementing the circular initiatives selected. In other words, a combination of enablers can be used during the implementation. Some examples of potential enablers follow to illustrate the concept. + +Various tools such as programmes in secondary and tertiary education and training, as well as vocations can be used to promote circularity, overcome awareness gaps and enhance skills and competencies. Existing literature can also be disseminated to the public, as well as to various related entities. Circular action items in different industries require specialized knowledge and skills (e.g., e-waste management, refurbishing manufactured items). Expertise, knowledge and even awareness of different circularity topics may not necessarily be readily available in cities. Hence, training and awareness programmes can be developed to close these skills gaps. + +Lack of skills and expertise among the public, as well as among policymakers, can be a potential barrier. Hence, capacity building, peer learning and twinning among cities can boost potential action items (policy levers). Formal professional programmes in the form of skill-building training may help to build capacity for circularity. However, other mechanisms can also be used for this purpose. Experts and individuals who are knowledgeable about circularity may train potential and promising individuals in a city. Additionally, cities that have vast experience in implementing circularity may assist other prospective cities in their journey towards becoming circular. + +Cultural and behavioural patterns (e.g., in recycling) may represent barriers to enacting circular city actions. It might be beneficial to inform and explain the benefits of circular actions to related stakeholders. In such cases, behavioural changes are required from city inhabitants and circular service providers. Nudging techniques, targeted communication and various incentives may be utilized to induce behavioural changes in a city. + +Urban industrial symbiosis initiatives may be utilized to exchange resources (i.e., by-products, waste) within an industry or across industries at city level. Such resource flows between organizations create significant benefits and opportunities. The by-products or waste of one industry can act as raw materials for another. This enables the creation of material looping among industries by using each other's by-products or waste, consequently reducing industrial waste in a city and thereby contributing to circularity. + +A holistic, high-level approach to circularity, from strategic planning to policymaking in the public and private sectors, can also boost circular city outputs. Different cities worldwide, as well as nations, have already developed comprehensive circular strategies within their jurisdictions. Amsterdam is an example of a city that has formulated a holistic vision and action agenda for the city and metropolitan area. It recognizes the circular economy as an important pillar in its sustainability agenda [b-Circle Economy]. Similarly, Scotland in the UK and Denmark have formulated circular economy strategies [b-DK-MEF] [b-Gov\_Scot]. + +Procurement can be used as a lever for circularity (e.g., procuring circular materials). Municipal governments have significant purchasing power in city economies. City procurement contracts may be prepared with a circular lens in mind. The case study on the development of a circular procurement framework in Toronto, Canada [b-ITU-T L-Suppl.50] provides an example of using procurement as a lever for circularity. Procurement policies and procurement contracts can specify purchased goods and services to comply with various circular targets in a city. Circular action items can provide + +guidance in formulating specifications for procured goods and services. The re-use, recycling and remanufacturing of materials, components and their packaging may be indicated during procurement. Procurement can play an important role not only in changing behaviour but also in overcoming the lack of circular economy markets. + +Financial incentives can be used for boosting circularity (e.g., breaks, reductions, exemptions and holidays for tax; lower loan rates; impact investment). Suppliers of circular goods and services can be made eligible to receive the benefits of these financial incentives. Favourable loan rates and green bonds can also be used to assist suppliers of circular goods and services. + +PPPs and other appropriate financial mechanisms may be used to boost circularity. Circular action items have significant benefits and positive impacts; hence, both the public and the private sector have a favourable stake in achieving them. This allows the formation of PPPs [b-IBRD-WB] whereby costs and benefits of circularity are shared among them [b-Hongo]. The public sector can opt to utilize PPP as a procurement alternative for implementing circular city initiatives. PPPs require upfront systematic thinking about various decisive factors such as the costs of implementing different circular city actions, their benefits and timing [b-PPPLRC]. However, sufficient benefits and positive impacts exist in most cases to justify a PPP approach whereby incentives are aligned among the partners [b-Ramanathan]. + +R&D programmes may be formulated and implemented in collaboration with the academia and private sector to boost circularity [b-EC 2017]. R&D programmes may be undertaken at the city or national levels, as well as at the regional level [b-MOVECO]. Circularity contains new areas of research that require further exploration and development. R&D programmes may play a key role in enhancing innovation in circular cities and boosting intellectual property, which can then be put into practical use and potentially commercialized. + +Regulations may be used as policy levers and tools to catalyse circular city actions (e.g., technical or compliance standards; product, trade, waste or safety regulations). Existing circular-related regulations such as waste management regulations, industry (vertical) regulations (e.g., chemical regulations [b-EC-Reg-1997], classification, labelling and packaging [b-EC-Reg-1272]) need to be taken into account during the implementation. Furthermore, new regulations, national laws and directives (legislation) may provide an enabling framework to encourage and boost circularity. At the city or national level, a supportive regulatory framework can direct the circularity processes and enable stakeholders to coordinate efforts and operate in an appropriate manner. + +International standards or Recommendations also offer one of the most consistent and reliable ways to measure and improve circularity in cities. Often developed through a collaborative and participatory process, they contain guidelines and frameworks that provide a solid foundation for overcoming different challenges of circular cities. Multiple global platforms have already taken the initiative to facilitate this transition. For example, ITU-T Study Group 5, *Environment, climate change and circular economy*, has been working with its membership to develop Recommendations that improve circularity in cities. One of these is [b-ITU-T L.1020], which provides guidance on how operators could work with their supply chain to improve the circular economy aspect of ICT goods and networks. ITU-T Study Group 20, *Internet of things, smart cities and communities*, has also developed Recommendations that enable the deployment of Internet of things technologies in a coordinated and sustainable manner. In addition, the Focus Group, *Environment efficiency for artificial intelligence and other emerging technologies*, is also working as a global platform to identify the standardization needs for developing a sustainable approach to artificial intelligence and other emerging technologies. The work of these groups provides valuable guidance for implementing circular actions and city stakeholders are encouraged to participate in their work. + +Certification programmes may be formulated to incentivize and encourage the public and the private sectors to support circular actions. Successful implementation would be recognized under certification programmes and would encourage similar or novel implementation in a city. + +Engaging a broad range of stakeholders may increase the likelihood of success for implementation of circularity actions (e.g., public sector, private sector, academia, individuals, NGOs and civil society in general). Global platforms, such as the U4SSC, provide a collaborative space in which to engage in dialogue and foster innovations in circular cities. + +Nurturing a rich innovative ecosystem, one that encourages entrepreneurs and SMEs to address circularity challenges, would help in boosting circularity in a city. Incubators, accelerators, hackathons, etc. might be leveraged for enriching the city innovation ecosystem based on the principles of circularity. Since circularity is predominantly a novel area that requires significant innovation, start-up and SME support would be highly important in increasing the likelihood of its success in the long run. + +The preceding examples illustrate a list of potential enablers that can catalyse different circular city actions. Each city can formulate a set of enablers based on its own characteristics. The appropriate set of enablers can be selected based on their applicability, expected impact, cost and various other requirements. + +## **Step 4: Assessment of projected circularity impact** + +This step involves either interim or final assessment of the results of implementing circularity initiatives or action items. Cities are strongly recommended to retrospectively and objectively conduct assessments and compare actual outcomes with those intended. + +If the city had adopted circularity KPIs with target values and target implementation timeframes for circularity initiatives or action items, it would be highly beneficial for the city to evaluate whether the targets have been met. + +Similarly, the city can evaluate various enablers based on their effectiveness during implementation. Any identified implementation gaps should be addressed and corrected in due course. Lessons learnt can be used to understand the positive and adverse consequences of circularity initiatives or strategic action items. Positive aspects of successful circularity initiatives may potentially be cross-utilized among other circularity initiatives or action items. For example, a successful policy in one initiative may trigger the use of a similar policy approach in another. Such examples can be extended to other enablers as well. On the other hand, ineffective enablers should be relinquished in due course. + +Circularity initiatives or action items are interventions in an urban context and, inevitably, will lead to various transformations. Therefore, it is important to assess their impact retrospectively. An *ex-post* impact assessment would be highly beneficial in understanding various social, economic and environmental changes that have occurred in the city and compare them to those intended prior to implementation. + +The comparison of *ex-ante* and *ex-post* impact assessments will indicate deviations in terms of intended and actual outcomes. Such impact assessments may aid in planning more accurately in due course or fine-tuning circularity initiatives or action items. + +# **9 Conclusions and recommendations** + +Circularity in the context of cities is a relatively novel concept that offers significant opportunities. This Recommendation has identified a generic approach to promoting circular actions in cities. This Recommendation is complemented by 17 case studies. The case studies illustrate non-exhaustively the substantial opportunity for promoting circularity inherent in cities across the world. The following conclusions could be drawn based on the research conducted to prepare this Recommendation as well as the case studies. + +- The circularity concept can be extended beyond solely economic activities to other social and environmental areas. +- City assets and products can all be considered as potential inputs for circular actions. + +- Circular cities optimize resource consumption by extending their lifetime and efficient use. +- Circular actions reduce the quantity of waste in cities, contributing significantly to more efficient use of natural resources and protecting the environment. +- A circular economy not only stimulates economic growth but also creates a positive social and environmental impact. +- Circularity provides innovative opportunities for cities and encourages entrepreneurship for new businesses, the creation of new industries, as well as social and environmental entrepreneurship. +- Cross-sectorial collaboration through PPPs is crucial for the implementation of circularity. The successful implementation of circularity actions may require adjustments in supply chains and may create new synergies within and across industries (e.g., industrial symbiosis). +- Circularity is a novel concept that necessitates a new approach in the way cities acquire, manage and consume their vast number of resources and assets. +- Circular cities contribute positively to achieving SDGs within their own context. +- The likelihood of success for circular cities is significantly increased by broadening stakeholder engagement and participation. +- An appropriate mix of enablers (defined in this Recommendation) will be beneficial for accelerating and sustaining circular cities. +- The case studies demonstrate the successful circular initiatives carried out by different cities. Disseminating success stories and creating awareness among stakeholders are critical to scaling up circular initiatives at the national, regional and international levels. Hence, international cooperation will be the cornerstone for expediting uptake of circularity in cities. +- Circularity can be used as a tool to address the most pressing global challenges faced by cities such as climate change, economic growth and scarcity of resources. +- Circularity as a novel field requires investment in pertinent knowledge and skills enhancement, as well as long-term R&D programmes. + +The following case studies address the following circularity topics and are included in [b-ITU-T L-Suppl.50]. + +### **Energy efficiency in buildings** + +Toronto: A case study of cooling systems for buildings using deep lake water cooling + +## **City solid waste management** + +Spain: Promoting recycling of municipal waste + +India: Recycling of plastic waste through use in road construction + +### **Affordable housing and social inclusion** + +City of Vienna: House sharing in urban areas as a tool for social inclusion + +Kirinda, Sri Lanka: Wild coast tented lodge as best practice of building affordable housing using local construction materials + +## **Urban mobility** + +Dubai: Mobile solutions for ordering taxis and other transportation services, "E-hailing" + +### **Re-use of consumer goods and tools loaning** + +Toronto: Sharing/collaborative city, loaning home and gardening tools + +London: Crystal Palace library of things + +Delhi: Recycling discarded textiles to premium ware + +Munich: Halle 2 second-hand store as a hotspot of the local circular economy + +Finland: Consumer goods and tools loaning + +### **Reducing food waste** + +Mumbai: Collects surplus food at hotels and distribute to the poor + +Oslo: Circular bioresources – treatment of food waste, garden waste and sludge from wastewater + +## **Participatory urban planning** + +Melbourne: Participatory planning of public spaces + +## **Circularity to promote local businesses and digitization** + +Amsterdam: Circular economy into the ICT industry effectively + +Dubai: Circular ICT devices and infrastructure + +Toronto: Circular procurement framework + +# Bibliography + +- [b-ITU-T L.1020] Recommendation ITU-T L.1020 (2018), *Circular economy: Guide for operators and suppliers on approaches to migrate towards circular ICT goods and networks*. +- [b-ITU-T L.1430] Recommendation ITU-T L.1430 (2013), *Methodology for assessment of the environmental impact of information and communication technology greenhouse gas and energy projects*. +- [b-ITU-T L.1440] Recommendation ITU-T L.1440 (2015), *Methodology for environmental impact assessment of information and communication technologies at city level*. +- [b-ITU-T Y.4903] Recommendation ITU-T Y.4903 (2022), *Key performance indicators for smart sustainable cities to assess the achievement of sustainable development goals*. +- [b-ITU-T L-Suppl.50] ITU-T L-series Recommendations – Supplement 50 (2022), *Case studies on implementation of cities' circular actions*. +- [b-ISO 472] International Standard ISO 472:2013, *Plastics – Vocabulary*. +- [b-ISO/IEC 29142-3] International Standard ISO/IEC 29142-3:2013, *Information technology – Print cartridge characterization – Part 3: Environment*. +- [b-ISO 37120] International Standard ISO 37120:2018, *Sustainable cities and communities – Indicators for city services and quality of life*. +- [b-IBRD-WB] World Bank Group, ADB, EBRD, GI Hub, IADB, IsDB, OECD, UNECE, UNESCAP (2017). *Public-private partnerships – Reference guide*, Version 3. 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Dev.* **17**, pp. 48-56. doi: [10.1016/j.envdev.2015.09.002](https://doi.org/10.1016/j.envdev.2015.09.002) + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1630-202301-I_PDF-E/0538daaa5583c23e17db3a12f2281a55_img.jpg b/marked/L/T-REC-L.1630-202301-I_PDF-E/0538daaa5583c23e17db3a12f2281a55_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..d4d8969f805414689ab79cfd08c333d454d482b3 --- /dev/null +++ b/marked/L/T-REC-L.1630-202301-I_PDF-E/0538daaa5583c23e17db3a12f2281a55_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:636c3839edff955a5b6208530b05fa1c983ab153d90f00216517a7a99478b988 +size 7074 diff --git a/marked/L/T-REC-L.1630-202301-I_PDF-E/33ed1f9b27c7c21c797aa928b0f06851_img.jpg b/marked/L/T-REC-L.1630-202301-I_PDF-E/33ed1f9b27c7c21c797aa928b0f06851_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..0c8cf8dd91234d28a4c524c648b67499db935031 --- /dev/null +++ b/marked/L/T-REC-L.1630-202301-I_PDF-E/33ed1f9b27c7c21c797aa928b0f06851_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:4cf320abec3d54ebb5d60f2aabc1a9b6fd000f240bdd49036a2130b834c43614 +size 63782 diff --git a/marked/L/T-REC-L.1630-202301-I_PDF-E/a26e142d3df5bef41a84a9dd099d7825_img.jpg b/marked/L/T-REC-L.1630-202301-I_PDF-E/a26e142d3df5bef41a84a9dd099d7825_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..6b42d0294af3ffe5588d6fded0ae94de8e1f0796 --- /dev/null +++ b/marked/L/T-REC-L.1630-202301-I_PDF-E/a26e142d3df5bef41a84a9dd099d7825_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:0d7ec3a9c72a3f074a5f15a9f6fae8b442df5dbe179001c848d6dc88aaca90ed +size 50610 diff --git a/marked/L/T-REC-L.1630-202301-I_PDF-E/d26959f4514c26ca19c3d6f00da85956_img.jpg b/marked/L/T-REC-L.1630-202301-I_PDF-E/d26959f4514c26ca19c3d6f00da85956_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..d921f425d4a25ebe656762411c28282df8d294cd --- /dev/null +++ b/marked/L/T-REC-L.1630-202301-I_PDF-E/d26959f4514c26ca19c3d6f00da85956_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:dd85c999a2dcd60e7e4ed0c06b5f23db458b6b0ead4c0e7d5c7283d45da87bfe +size 140713 diff --git a/marked/L/T-REC-L.1630-202301-I_PDF-E/ebff22fb5dd6f50a90e44dca0f82f285_img.jpg b/marked/L/T-REC-L.1630-202301-I_PDF-E/ebff22fb5dd6f50a90e44dca0f82f285_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..92fce1d36ccc56eea387bb391b1028665f80cb5c --- /dev/null +++ b/marked/L/T-REC-L.1630-202301-I_PDF-E/ebff22fb5dd6f50a90e44dca0f82f285_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:d19d56ed29ad028e3e78b7b33fbc7213d51ce8bcf2ee605a43ae037b29e6ca16 +size 83275 diff --git a/marked/L/T-REC-L.1630-202301-I_PDF-E/raw.md b/marked/L/T-REC-L.1630-202301-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..c0dc94a55ec22bf45343e6fa3593198dd1acad9c --- /dev/null +++ b/marked/L/T-REC-L.1630-202301-I_PDF-E/raw.md @@ -0,0 +1,385 @@ + + +# Recommendation **ITU-T L.1630 (01/2023)** + +SERIES L: Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant + +Circular and sustainable cities and communities + +## --- **Framework of a building infrastructure management system for sustainable cities** + +![ITU logo](0538daaa5583c23e17db3a12f2281a55_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with white lines representing latitude and longitude, and the letters 'ITU' in a bold, blue, sans-serif font superimposed on the globe. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +### **ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT** + +| | | +|--------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node elements (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000–L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200–L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300–L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400–L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500–L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600–L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700–L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1630 + +## Framework of a building infrastructure management system for sustainable cities + +## Summary + +One of the sustainable development goals of a sustainable city is to build resilient and safe city assets. Building is one of the key city assets and is closely related to the circular and sustainable city. Typically, energy and firefighting equipment are key items of equipment within the building infrastructure and may affect the safety of people. Currently, many items of energy and firefighting equipment are separately deployed and managed, so there exist gaps between energy equipment management and firefighting equipment management. Recommendation ITU-T L.1630 defines the framework of a building infrastructure management system which improves the sustainability of a city, particularly of buildings as a city asset. The framework provides a holistic management of building infrastructure. It also presents service use cases composed of functional elements. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.1630 | 2023-01-13 | 5 | 11.1002/1000/15176 | + +## Keywords + +Building, building infrastructure, management system, sustainable city. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2023 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|----------------------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 1 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 2 | +| 6 Overview of building infrastructure management system..... | 2 | +| 6.1 Overview ..... | 2 | +| 6.2 Specific challenges for firefighting infrastructure management ..... | 4 | +| 6.3 Specific challenges for energy infrastructure management..... | 4 | +| 7 Framework for a building infrastructure management system ..... | 5 | +| 7.1 Conceptual framework of a building infrastructure management system (BIMS)..... | 5 | +| 7.2 Functional components of the building infrastructure management system (BIMS)..... | 6 | +| Appendix I – Service use cases..... | 8 | +| I.1 Service use case for firefighting equipment management..... | 8 | +| I.2 Service use case for energy efficiency management..... | 8 | +| Bibliography..... | 10 | + + + +# Recommendation ITU-T L.1630 + +## Framework of a building infrastructure management system for sustainable cities + +# 1 Scope + +This Recommendation describes a specification of the building infrastructure management system for a sustainable city, as follows: + +- Overview of the building infrastructure management system; +- Framework for the building infrastructure management system; +- Service use cases. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +None. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +None. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 firefighting infrastructure:** A set of equipment that protects or evacuates people by detecting and notifying fires, enables immediate firefighting activities at the early stage of a fire, and extinguishes fires by automatic or manual operation. + +**3.2.2 firefighting equipment:** An individual item of equipment consisting of a firefighting infrastructure and classified as communication-less legacy firefighting equipment and communication-capable firefighting equipment. + +**3.2.3 firefighting infrastructure management:** A function that supports the operation of fire alarm control equipment and communication using data model and provides intelligent firefighting equipment management service. + +**3.2.4 energy infrastructure:** A set of equipment that receives various types of energy such as electricity, gas and water from the energy providers and distributes the energy to the building infrastructure. + +**3.2.5 energy equipment:** An individual item of equipment consisting of an energy infrastructure and classified as energy receiving equipment and energy distribution equipment. + +**3.2.6 energy infrastructure management:** A function that supports the operation of energy equipment and communication using a data model and provides an intelligent energy equipment management service. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|-------------------------------------------| +| AI | Artificial Intelligence | +| BIMS | Building Infrastructure Management System | +| CoAP | Constrained Application Protocol | +| EES | Electrical Energy Storage System | +| HVAC | Heat, Ventilation and Air Conditioning | +| MQTT | Message Queuing Telemetry Transport | +| OCF | Open Connectivity Foundation | +| PV | Photovoltaic | + +# **5 Conventions** + +None. + +# **6 Overview of building infrastructure management system** + +## **6.1 Overview** + +A building infrastructure management system (BIMS) is a system that monitors and controls infrastructure consisting of various types of equipment. BIMS operates building equipment according to the building administrator's operation mode setting, monitors the real-time status of building infrastructure, and alarms a warning signal in a case of abnormal operation. Building infrastructure typically consists of firefighting, energy and environmental equipment. Figure 1 represents the typical structure and components of building infrastructure, which is broadly divided into three layers. The device layer consists of devices and controllers. The devices consist of monitoring devices such as various meters and sensors and actuation devices such as switches and valves. The device controllers connect the devices, perform information collection from them and control them. The control layer is composed of the communication system responsible for the transmission of information necessary for the operation of the infrastructure and the management system that performs actual control of the infrastructure. The management system in the management layer holistically manages the whole building infrastructure, communicates with the operator or manager, provides operation information and delivers operation commands. + +![Figure 1 – Typical structure of building infrastructure. The diagram shows a three-layer hierarchy. The top layer is the Management layer, containing a 'Management system' (represented by a computer icon) connected to a 'Building internal network/Internet'. The middle layer is the Control layer, consisting of four 'Communication controller' units connected to the network. The bottom layer is the Device layer, connected via a 'Building internal network'. It contains three 'Device controller' units. The first device controller is connected to a 'Switch', 'Meter', 'Valve', and 'Sensor'. The second is connected to a 'Valve' and 'Sensor'. The third is connected to a 'Switch', 'Meter', 'Valve', and 'Sensor'. Brackets on the right side label the layers: 'Management layer', 'Control layer', and 'Device layer'. A reference code 'L.1630(23)' is at the bottom right.](ebff22fb5dd6f50a90e44dca0f82f285_img.jpg) + +Figure 1 – Typical structure of building infrastructure. The diagram shows a three-layer hierarchy. The top layer is the Management layer, containing a 'Management system' (represented by a computer icon) connected to a 'Building internal network/Internet'. The middle layer is the Control layer, consisting of four 'Communication controller' units connected to the network. The bottom layer is the Device layer, connected via a 'Building internal network'. It contains three 'Device controller' units. The first device controller is connected to a 'Switch', 'Meter', 'Valve', and 'Sensor'. The second is connected to a 'Valve' and 'Sensor'. The third is connected to a 'Switch', 'Meter', 'Valve', and 'Sensor'. Brackets on the right side label the layers: 'Management layer', 'Control layer', and 'Device layer'. A reference code 'L.1630(23)' is at the bottom right. + +**Figure 1 – Typical structure of building infrastructure** + +Currently, there are several challenges for building infrastructure management. + +- Installation and operating cost + +In the installation stage of BIMS that supports the efficient operation and management of buildings, building owners tend to install only the most basic functions and modules in order to reduce construction costs. Thus, although building energy consumption information and management tools are continuously developed and provided by the BIMS industry, the opportunity to introduce them is often blocked according to existing practices. To additionally install a BIMS in the subsequent operation stage is generally accompanied by a relatively high cost, so it becomes more difficult to have a reasonable and systematic management opportunity. On the other hand, in the operation stage, it is common to outsource the management of buildings to third party service companies. In other words, although it varies depending on the size and use of the building, there are many cases of outsourcing to a management company that bundles expenses, cleaning and operation and management of facilities. As a result, the possibility of poor management increases. + +- Insufficient provision of energy consumption information and management tools + +As the importance of reducing greenhouse gases in preparation for climate change has been strengthened, the demands to increase energy efficiency of building have increased significantly. A conventional BIMS typically provides functions for status monitoring and controlling various equipment and systems in a building infrastructure. However, recently BIMSs have also begun to offer a function of providing energy consumption information, and it seems that efforts are being made to provide more advanced management tools. The advanced management tools refer to the simplified control function through comparison of the set value determined by the administrator with the current status value, and an advanced function that helps the administrator in the decision process or replaces the administrator's judgement function in the future. In order to develop and provide such an advanced management tool, it is necessary to collect a large amount of operation management information and develop a management technique through the analysis of this information, but it is known that the current system is insufficient to satisfy the demand level of customers. + +- Lack of interoperability between equipment and systems + +Insufficient provision of information required by building stakeholders for the systematic management of buildings is mainly due to a lack of effort on the part of the BIMS suppliers. However, a more fundamental reason for not providing sufficient information about the building infrastructure seems to be the lack of interoperability between building equipment and management systems. The conventional systems have been operated in an exclusive and closed form, and as a result, it is impossible to share components (hardware such as measurement and control equipment and various operation management software), and it is not possible to share building operation information without the help of the supplier. In order to respond to the environment-related regulations such as greenhouse gas reduction, building stakeholders are demanding functions that enable a more effective energy management capability beyond simple building management functions. + +## 6.2 Specific challenges for firefighting infrastructure management + +A number of fire accidents have occurred in various facilities and caused considerable harm to people. In particular, the outbreak of fires in crowded facilities where large numbers of people are gathered has caused major casualties. In most cases, the cause of accidents that have caused large-scale personal injury is mostly due to fire detection equipment not working properly or intentional turning off of fire alarm equipment. Whether or not the firefighting equipment is in operation determines the scale of harm to people in the event of a fire. However, many firefighting infrastructures are currently not properly managed, and poor management of firefighting infrastructures is recognized as one of the major causes of large-scale accidents. The investigation on the status of firefighting infrastructure management shows high failure rates and the number of malfunctions of the firefighting infrastructure shows an increasing trend. Thus, there is an urgent need for a way to continuously manage the condition of firefighting equipment without errors. There are three major causes of poor management of firefighting infrastructures: + +- Physical factor: the limit of the number of people and time required for firefighting equipment inspection. +- Technical factor: decreased reliability and lack of monitoring data. +- Human resources factor: not enough firefighting infrastructure administrators. + +Due to these reasons, firefighting infrastructures are not properly managed. In order to mitigate these poor management situations, it is recognized that a system for real time management of the firefighting infrastructure is necessary. In particular, firefighting equipment is installed in a special form due to the restrictions of the relevant laws and regulations, and the connection between systems in other fields is not possible. Therefore, in order to resolve the problems of conventional firefighting infrastructure management, it is required to develop a framework defining the firefighting infrastructure management system. + +## 6.3 Specific challenges for energy infrastructure management + +Currently, there are two challenges for building energy infrastructure management. + +- Separate installation of systems by providers and incomplete system integration + +First, various automation systems such as mechanical equipment, power supply equipment, lighting and transportation equipment are installed in the building. However, they are individually installed and operated according to the specific services. + +- Lack of integration with conventional building management systems + +As described above, building infrastructure is installed and operated for each service and energy infrastructure is also separately managed. In other words, the building energy infrastructure management system is not integrated with the BIMS and it is currently being built and operated as a separate system. As a result, the initial investment cost increases due to the redundant installation of + +the systems, as well as the operation of the closed operating system. Therefore, it is difficult to improve energy efficiency through holistic analysis and diagnosis of building energy consumption due to poor information exchange between systems. It is also difficult to operate and manage facilities properly. These are the current status and challenges in energy infrastructure management in buildings. + +# 7 Framework for a building infrastructure management system + +## 7.1 Conceptual framework of a building infrastructure management system (BIMS) + +The conceptual framework of a BIMS depicted in Figure 2 consists of the building infrastructure and the building infrastructure management system. As described in clause 6, building infrastructure is typically composed of energy equipment, firefighting equipment and environmental equipment. The building infrastructure is connected to the BIMS through the local network in the building. The BIMS consists of four sub-functions, namely the platform common function, equipment management function, application specific service function, and service interface function. The platform common function performs the data collection from the building infrastructure, storing the gathered data and data analysis using an AI engine. The equipment management function performs the management for the specific equipment, i.e., energy, firefighting and environmental equipment in the building infrastructure. Equipment-specific services are provided by the application specific function. Finally, the service interface function supports the interaction between BIMS and the third party building infrastructure management service provider. BIMS can be communicated with the city-level management platform, for example, a smart sustainable city management platform that monitors and manages the whole infrastructure in a smart city. + +![Figure 2 – Conceptual framework of building infrastructure management system (BIMS). The diagram shows the flow of data and control from building infrastructure (Energy, Firefighting, and Environment equipment) through a local network to the BIMS. The BIMS is structured into four layers: Service interface function, Application specific service function (Firefighting, Energy efficiency, Environment), Equipment management function (Firefighting, Energy, and Environment equipment management), and Platform common function (Data acquisition, management, analysis, repository, and AI engine). The BIMS interacts with a Building infrastructure management service provider and a Smart sustainable city management platform via service interfaces.](d26959f4514c26ca19c3d6f00da85956_img.jpg) + +The diagram illustrates the conceptual framework of a Building Infrastructure Management System (BIMS). On the left, the **Building infrastructure** is categorized into three types of equipment, each connected to a central **Building local network** cloud: + +- Energy equipment**: High-voltage electrical equipment, Renewable energy equipment, Load: Light, EV, ... etc. +- Firefighting equipment**: Fire detection device, Fire alarm device, Fire detection control and indicating equipment, Sprinkler etc. +- Environment equipment**: HVAC (Heating, ventilation, and air conditioning), Sensor: Temperature, humidity, ... etc. + +The **Building local network** connects to the **Building infrastructure management system (BIMS)**, which is structured as a stack of four layers: + +- Service interface function**: The top layer, which interacts with the **Building infrastructure management service provider** and the **Smart sustainable city management platform** via a **Service interface**. +- Application specific service function**: Contains sub-functions for **Firefighting**, **Energy efficiency**, and **Environment**. +- Equipment management function**: Contains sub-functions for **Firefighting equipment management**, **Energy equipment management**, and **Environment equipment management**. +- Platform common function**: The bottom layer, containing **Data acquisition interface**, **Data management** (which includes **Data analysis** and **Data repository**), and an **AI engine**. + +A vertical bar on the right side of the BIMS stack is labeled **Security and system management function**. The entire BIMS stack is connected to the **Smart sustainable city management platform** on the far right. + +Figure 2 – Conceptual framework of building infrastructure management system (BIMS). The diagram shows the flow of data and control from building infrastructure (Energy, Firefighting, and Environment equipment) through a local network to the BIMS. The BIMS is structured into four layers: Service interface function, Application specific service function (Firefighting, Energy efficiency, Environment), Equipment management function (Firefighting, Energy, and Environment equipment management), and Platform common function (Data acquisition, management, analysis, repository, and AI engine). The BIMS interacts with a Building infrastructure management service provider and a Smart sustainable city management platform via service interfaces. + +Figure 2 – Conceptual framework of building infrastructure management system (BIMS) + +## **7.2 Functional components of the building infrastructure management system (BIMS)** + +### **7.2.1 Building infrastructure** + +There exist many types of equipment, such as for energy, water, gas, heating, cooling, and firefighting, within a building. This Recommendation considers energy, firefighting and environment equipment, which are major components for building management. Further, this Recommendation deals with communication-capable equipment. As shown in Figure 2, the building infrastructure typically consists of energy equipment, firefighting equipment and building environment equipment. Energy equipment can be further categorized into energy receiving equipment, energy load and distributed energy resources in the building. + +The building infrastructure uses various energy sources such as electricity, gas and water supplied by each provider. These energy sources are supplied through an energy distribution equipment and distributed within the building. The safety management of the energy equipment is important, especially that of power distribution equipment that receives high-voltage electricity and converts it to low voltage and distributes the power in the building infrastructure and may cause accidents such as fire or personal injury. Also, disruption to electricity may cause the shutdown of the whole building infrastructure. Energy loads include transportation equipment, electric heat loads and building specific loads. Transportation equipment is the elevators and escalators. The electric heat loads are appliances, office computers, and so on. The environmental equipment includes HVAC (heating, ventilation and air conditioning), water supply and lighting equipment, which are used to manage the comfort of the building environment for the occupants. + +### **7.2.2 Building infrastructure management system** + +The building infrastructure management system monitors and manages the equipment in the building infrastructure. The platform common function collects status data of building equipment through data acquisition interfaces. Data collection can be performed by various communication protocols such as conventional non-IoT protocols (serial communication protocol, MODBUS, etc.) and IoT protocols (MQTT, COAP, OCF, etc.). The collected data are stored, analysed using an AI engine and managed. When collecting equipment status data, the data are collected in the form of data profiles through data model design. In order to efficiently perform the data management function, the profile units are classified and managed according to the characteristics of the data. Data are classified and stored into equipment configuration data, real-time status measurement data and control data. The data are stored in a database reflecting the characteristics provided by the building infrastructure management services. The AI engine has a function of providing a library suitable for the service algorithm provided by BIMS. + +The equipment management function performs the equipment-specific management functions. The firefighting equipment management function performs the real-time management of firefighting equipment using ICT communication. When an abnormal event such as fire accident is detected, it informs the administrator of the equipment of the event to and also it notifies the accident to the local fire station. The energy equipment management function manages the stable operation of energy equipment, especially the safety perspective. The energy equipment management function monitors the status of the energy equipment and manages the safety level and equipment residual lifetime. The environment equipment management function manages the whole environment including temperature, humidity, lighting, and so on. + +The application specific service function provides the specific services for building infrastructure. The energy efficiency service function performs various services including energy load estimation and scheduling, the electrical energy storage system (EESS) charging and discharging, energy equipment alarm and control, reporting for the building administrator and the provision of status visualization. The firefighting service function holistically manages the data collected from firefighting infrastructure and provides interfaces for interoperate with the fire department or concerned persons in case of an abnormal event so that appropriate responses can be made. The + +environmental service provides a comfortable environment for the building occupants through indoor air quality, thermal comfort and illuminance control, and an algorithm suitable for the purpose is applied. The application-specific service function provides BIMS users with visualization capability including visual monitoring, statistics, alarm and warning, reporting and control functions for building infrastructure status, energy usage status, indoor environment, energy cost, and so on. + +The security and system management function is performed at all layers of data communication and service, and system management performs operation management and updates related issues for all components of BIMS. The service interface function provides interfaces for various service providers to interact with the BIMS. + +### **7.2.3 Building infrastructure management service provider** + +The building infrastructure management service provider is a third party service provider that supports the diagnosis and periodic maintenance of the building infrastructure and BIMS. The equipment diagnosis service provides a real-time online or offline inspection based on customer information and the customer's inspection history. Through this, it is possible to check the safety level of each inspection equipment and forecast the expected lifetime of each item of equipment under inspection. The periodic maintenance service involves check and record the data uploading and downloading communication between building infrastructure equipment and BIMS to verify that they are properly functioning. + +## Appendix I + +## Service use cases + +(This appendix does not form an integral part of this Recommendation.) + +### I.1 Service use case for firefighting equipment management + +Firefighting equipment installed in buildings sends the equipment status data and event information to BIMS. The event information indicates the occurrence of an accidental fire or a fault in the equipment. The firefighting equipment supports communication functions and can be directly connected to the BIMS through the building's local network. The BIMS notifies the event information to the building owner or administrator. After being informed by the BIMS about the event related to the firefighting equipment, the administrator checks the event information and takes appropriate action if necessary. The event information can be classified based on an identifier for each item of equipment. In the case of equipment event data, the administrator checks the identifier and event information of the equipment to verify whether the firefighting equipment is in abnormal state and then performs appropriate action. In the case of a fire detection event, the administrator performs an early response by checking the fire detection equipment and fire detection area information through the BIMS. In the case of an accidental fire, the information is notified to related parties and safety management organizations such as the fire station. + +![Sequence diagram for firefighting equipment management service use case](a26e142d3df5bef41a84a9dd099d7825_img.jpg) + +``` +sequenceDiagram + participant FE as Firefighting equipment + participant BIMS as Building infrastructure management system + participant BA as Building administrator + participant FS as Fire station + + FE->>BIMS: Equipment status/event information + BIMS->>BA: Notification of events in firefighting equipment + BA->>FS: Notification of fire in building + BIMS->>FS: Notification of fire in building + BIMS->>BA: Control command to event equipment + BA->>FE: Control command to event equipment +``` + +The diagram illustrates the interaction between four entities: Firefighting equipment, Building infrastructure management system (BIMS), Building administrator, and Fire station. The sequence of messages is as follows: 1. Firefighting equipment sends 'Equipment status/event information' to BIMS. 2. BIMS sends 'Notification of events in firefighting equipment' to Building administrator. 3. Building administrator sends 'Notification of fire in building' to Fire station. 4. BIMS also sends 'Notification of fire in building' to Fire station. 5. BIMS sends 'Control command to event equipment' to Building administrator. 6. Building administrator sends 'Control command to event equipment' to Firefighting equipment. The diagram is labeled 'L.1630(23)' in the bottom right corner. + +Sequence diagram for firefighting equipment management service use case + +Figure I.1 – Service use case for firefighting equipment management + +### I.2 Service use case for energy efficiency management + +In general, distributed energy resources such as photovoltaic (PV) equipment and EESS are installed and used in a building for energy efficiency. PV is not a resource that can control the amount of power generation because the amount of power generation varies according to changes in the weather. EESS can be controlled through the charging and discharging of electricity, so charging and discharging is scheduled considering the building load usage, PV generation and electricity tariff plan. Figure I.2 shows a use case for using EESS for increasing building energy efficiency. BIMS collects real-time power data from the load and the meter installed in the energy infrastructure, in particular PV generation equipment. In the building energy efficiency service function in BIMS, an EESS charge and discharge scheduling algorithm is periodically performed for efficient energy management. EESS charge and discharge scheduling is optimized through forecasting of electric loads and PV generation forecasting. Energy efficiency service function controls the EESS by charging and discharging scheduling, and provides a visualization service for the EESS charging and discharging status to the user [b-IEC 62933-3-3]. + +![Sequence diagram for energy efficiency management showing interactions between five entities: Electricity load, Distributed energy resources, Energy equipment management function (BIMS), Energy efficiency function (BIMS), and Building administrator.](33ed1f9b27c7c21c797aa928b0f06851_img.jpg) + +``` + +sequenceDiagram + participant EL as Electricity load (Energy equipment) + participant DER as Distributed energy resources (Renewable energy and EESS) + participant BIMS as Energy equipment management function (BIMS) + participant EEF as Energy efficiency function (BIMS) + participant BA as Building administrator + + EL->>BIMS: Real-time load and status information + DER->>BIMS: Real-time status information + BIMS->>EEF: Real-time load and status of energy information + EEF->>BIMS: Calculated operation mode of EESS based on forecasted load and PV power generation + BIMS->>DER: Control command for operation mode of EESS + BIMS->>BA: Visualization of energy equipment status + +``` + +The diagram illustrates the service use case for energy efficiency management. It features five lifelines: Electricity load (Energy equipment), Distributed energy resources (Renewable energy and EESS), Energy equipment management function (BIMS), Energy efficiency function (BIMS), and Building administrator. The sequence of interactions is as follows: + + +- The Electricity load sends "Real-time load and status information" to the Energy equipment management function (BIMS). +- The Distributed energy resources send "Real-time status information" to the BIMS. +- The BIMS sends "Real-time load and status of energy information" to the Energy efficiency function (BIMS). +- The Energy efficiency function (BIMS) sends a "Calculated operation mode of EESS based on forecasted load and PV power generation" back to the BIMS. +- The BIMS sends a "Control command for operation mode of EESS" to the Distributed energy resources. +- Finally, the BIMS sends a "Visualization of energy equipment status" to the Building administrator. + +L.1630(23) + +Sequence diagram for energy efficiency management showing interactions between five entities: Electricity load, Distributed energy resources, Energy equipment management function (BIMS), Energy efficiency function (BIMS), and Building administrator. + +**Figure I.2 – Service use case for energy efficiency management** + +## Bibliography + +- [b-IEC 62933-3-3] IEC TS 62933-3-3:2022, *Electrical energy storage (EES) systems – Part 3-3: Planning and performance assessment of electrical energy storage systems – Additional requirements for energy intensive and backup power applications.* + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | 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+1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:e0649cbc54055ce8a92f233e8999429963b079b26ad3630eaeab68a3a037a8fe +size 73159 diff --git a/marked/L/T-REC-L.1631-202309-I_PDF-E/raw.md b/marked/L/T-REC-L.1631-202309-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..77f1b5492068bae9fcdaa14d8e9502b1b452d7e5 --- /dev/null +++ b/marked/L/T-REC-L.1631-202309-I_PDF-E/raw.md @@ -0,0 +1,420 @@ + + +# Recommendation + +## **ITU-T L.1631 (09/2023)** + +SERIES L: Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant + +Circular and sustainable cities and communities + +--- + +## **Reference model for firefighting infrastructure management systems for buildings in sustainable cities** + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with white lines representing latitude and longitude, and the letters 'ITU' in a bold, blue, sans-serif font overlaid on the globe. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +### **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|--------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| Infrastructure including node elements (except cables) | L.200-L.249 | +| General aspects and network design | L.250-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| Optical fibre cable maintenance | L.300-L.329 | +| Infrastructure maintenance | L.330-L.349 | +| Operation support and infrastructure management | L.350-L.379 | +| Disaster management | L.380-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1631 + +## Reference model for firefighting infrastructure management systems for buildings in sustainable cities + +## Summary + +Recommendation ITU-T L.1631 provides an overview of a firefighting infrastructure management system (FIMS), defines the reference model of the FIMS, and provides use cases for the FIMS for buildings in sustainable cities. + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.1631 | 2023-09-22 | 5 | 11.1002/1000/15601 | + +## Keywords + +Building, firefighting infrastructure, sustainable cities. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2023 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|--------------------------------------------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 1 | +| 4 Abbreviations and acronyms ..... | 1 | +| 5 Conventions ..... | 2 | +| 6 Overview of firefighting infrastructure management system for buildings in sustainable cities ..... | 2 | +| 7 Reference model of firefighting infrastructure management system for buildings in sustainable cities ..... | 3 | +| 7.1 Overview ..... | 3 | +| 7.2 Functional entities ..... | 3 | +| 8 Use cases of firefighting infrastructure management system for buildings in sustainable cities ..... | 4 | +| 8.1 Use case for equipment registration and management ..... | 4 | +| 8.2 Use case for unusual condition detection ..... | 5 | +| 8.3 Use case for emergency recovery request ..... | 6 | +| 8.4 Use case for emergency recovery cancellation ..... | 7 | +| Bibliography..... | 9 | + + + +# Recommendation ITU-T L.1631 + +## Reference model for firefighting infrastructure management systems for buildings in sustainable cities + +## 1 Scope + +This Recommendation defines the reference model of a firefighting infrastructure management system (FIMS) for buildings in sustainable cities considering: + +- Overview of the FIMS for buildings; +- Reference model of the FIMS for buildings; +- Use cases of the FIMS for buildings. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +None. + +## 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following term defined elsewhere: + +**3.1.1 firefighting infrastructure** [b-ITU-T L.1630]: A set of equipment that protects or evacuates people by detecting and notifying fires, enables immediate firefighting activities at the early stage of a fire and extinguishes fires by automatic or manual operation. + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 fire detection and identifying equipment (FDIE)**: Equipment that generates a set of fire-related data and sends it to the firefighting infrastructure management system (FIMS). + +**3.2.2 firefighting infrastructure management system (FIMS)**: A system that manages one or more FDIE(s) and supports effective response through coordination with firefighting infrastructure management service providers and firefighting stations. + +## 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|-----------------------------------------------| +| FDIE | Fire Detection and Identifying Equipment | +| FE | Functional Entities | +| FIMS | Firefighting Infrastructure Management System | + +## 5 Conventions + +None. + +## 6 Overview of firefighting infrastructure management system for buildings in sustainable cities + +A number of fire accidents have occurred in various facilities, causing significant harm to people in buildings. Many of these large-scale accidents resulting in high casualties were primarily caused by malfunctioning fire detection equipment within the buildings. In sustainable cities, building infrastructures, including firefighting infrastructure need to be designed to support durability, adaptability, and easy maintenance. However, the conventional firefighting infrastructure in buildings known as fire detection and identifying equipment (FDIE), is typically managed at the building level, making it challenging to provide comprehensive management services for sustainable cities. To address this issue, it is essential to define a comprehensive reference model for a firefighting infrastructure management system (FIMS) specifically tailored to buildings in sustainable cities. + +Figure 1 provides an overview of the FIMS and the related entities for buildings in sustainable cities. The in-building firefighting infrastructure consists of multiple FDIEs, which are responsible for managing fire-related devices installed in a building. The FDIEs are managed by the FIMS via the building's local network. The FIMS reports any unusual conditions such as malfunctions of fire related devices to the firefighting infrastructure service provider via the service interface. In addition, the FDIE can request an emergency recovery to the firefighting station and report analysis data for the emergency recovery firefighting safety management organization via a city management interface. The firefighting infrastructure service provider is responsible for managing fire-related service management for fire-related devices within a building. The firefighting station serves as a facility that conducts fire emergency recovery activities, including firefighting operations. The firefighting safety management organization is a public agency that assumes responsibility for fire prevention and suppression within a municipality, county, state, nation, or a special district. + +![Figure 1: Overview of firefighting infrastructure management system (FIMS) and fire related entities for buildings in sustainable cities. The diagram shows the flow of information and control between various components. On the left, 'In-building firefighting infrastructure' includes 'Fire detection device', 'Fire alarm device', 'Sprinkler', and 'etc.' connected to an 'FDIE (Fire detection and identifying equipment)'. The FDIE contains sub-modules for 'Fire-related device management', 'Fire detection management', and 'Fire alarm management'. This is connected via a 'Building local network' to the 'FIMS (Firefighting infrastructure management system)'. The FIMS contains sub-modules for 'Fire-related service management', 'Fire-related equipment management', and 'Fire-related data management'. The FIMS connects upwards via a 'Service interface' to the 'Firefighting infrastructure management service provider' (represented by an icon of three buildings). It also connects rightwards via a 'City management interface' to the 'Firefighting safety management organization' (represented by an icon of people and a building) and the 'Firefighting station' (represented by an icon of a fire truck and building). A small label 'L.1631(23)' is in the bottom right corner of the diagram area.](c0e88e4bd3a209b66ee7cb67e1cec2be_img.jpg) + +Figure 1: Overview of firefighting infrastructure management system (FIMS) and fire related entities for buildings in sustainable cities. The diagram shows the flow of information and control between various components. On the left, 'In-building firefighting infrastructure' includes 'Fire detection device', 'Fire alarm device', 'Sprinkler', and 'etc.' connected to an 'FDIE (Fire detection and identifying equipment)'. The FDIE contains sub-modules for 'Fire-related device management', 'Fire detection management', and 'Fire alarm management'. This is connected via a 'Building local network' to the 'FIMS (Firefighting infrastructure management system)'. The FIMS contains sub-modules for 'Fire-related service management', 'Fire-related equipment management', and 'Fire-related data management'. The FIMS connects upwards via a 'Service interface' to the 'Firefighting infrastructure management service provider' (represented by an icon of three buildings). It also connects rightwards via a 'City management interface' to the 'Firefighting safety management organization' (represented by an icon of people and a building) and the 'Firefighting station' (represented by an icon of a fire truck and building). A small label 'L.1631(23)' is in the bottom right corner of the diagram area. + +**Figure 1 – Overview of firefighting infrastructure management system (FIMS) and fire related entities for buildings in sustainable cities** + +The FDIE performs the following functions: + +- registering and managing fire-related devices with their generated data, +- detecting a fire signal or the capability failures of the devices, +- identifying the location of fire accidents that occur within the building, +- alerting the fire signal to fire alarm devices, sprinklers, etc. installed in the building, and +- sending a set of data related to both fire accidents and devices' status to the FIMS via the building's local network. + +The FIMS performs the following functions: + +- managing one or more FDIEs within the building, +- receiving a set of data related to fire accidents or devices' status from the FDIE, +- determining whether an emergency recovery call is necessary based on the received data, +- requesting an emergency recovery assistance from the firefighting infrastructure management service provider through a service interface if required, +- reporting the emergency recovery situation, along with the set of data to the firefighting safety management organization or the firefighting station via city management interfaces if necessary, and +- recording the gathered data, including information regarding fire accidents and the health status of fire-related devices installed in the building. + +## 7 Reference model of firefighting infrastructure management system for buildings in sustainable cities + +### 7.1 Overview + +Figure 2 represents the block diagram for the reference model of the FIMS in buildings. The FIMS is connected to one or more FDIEs that are installed in the buildings via the building's local network. + +![Figure 2: Overview of reference model for firefighting infrastructure management system (FIMS). The diagram shows multiple FDIE (Fire detection and identifying equipment) blocks on the left, each containing functional entities (FEs): Device registration FE, Device status monitoring FE, Fire detection FE, Data generation FE, Fire alert FE, and Location FE. The FDIEs are connected to a central FIMS (Firefighting infrastructure management system) block on the right. The FIMS contains FEs: Equipment registration FE, Data repository FE, Decision making FE, Equipment status monitoring FE, and Data analysis FE. External interfaces include Fire detection interface, Fire alarm interface, Firefighting service interface, and City management interface. The diagram is labeled L.1631(23).](0b87abe67b21a93777287649c33e755d_img.jpg) + +Figure 2: Overview of reference model for firefighting infrastructure management system (FIMS). The diagram shows multiple FDIE (Fire detection and identifying equipment) blocks on the left, each containing functional entities (FEs): Device registration FE, Device status monitoring FE, Fire detection FE, Data generation FE, Fire alert FE, and Location FE. The FDIEs are connected to a central FIMS (Firefighting infrastructure management system) block on the right. The FIMS contains FEs: Equipment registration FE, Data repository FE, Decision making FE, Equipment status monitoring FE, and Data analysis FE. External interfaces include Fire detection interface, Fire alarm interface, Firefighting service interface, and City management interface. The diagram is labeled L.1631(23). + +**Figure 2 – Overview of reference model for firefighting infrastructure management system (FIMS)** + +### 7.2 Functional entities + +The FDIE has the following functional entities (FEs): + +- device registration FE: registers fire-related devices along with their relevant data in buildings; + +- device status monitoring FE: obtains the generated data from fire-related devices; +- fire detection FE: detects fire signals from fire detection devices or receives manual triggering signals in buildings; +- fire alert FE: alerts the fire signal to fire alarm devices, sprinklers, etc. installed in buildings; +- location FE: obtains location information of the fire accident in a building; +- data generation FE: generates a set of data related to fire signals or devices' status. + +The FIMS has the following FEs: + +- equipment registration FE: registers one or more FDIEs with their relevant data in the buildings; +- equipment status monitoring FE: obtains generated data from the FDIEs; +- data repository FE: records the gathered data, including fire accident-related information and the health status of fire-related devices; +- decision making FE: determines whether the fire accident requires emergency recovery based on the received set of data by interworking with one or more FDIEs; +- data analysis FE: analyses the received set of data to request emergency recovery or reports malfunctioning of fire-related devices installed in buildings. + +## **8 Use cases of firefighting infrastructure management system for buildings in sustainable cities** + +### **8.1 Use case for equipment registration and management** + +Figure 3 shows the workflow of the FIMS in the case of FDIE registration and management. The FDIE is responsible for registering fire-related devices in buildings and generating their related data, including capabilities and location for registration. The FDIE transmits its registration data to the FIMS and awaits acknowledgement. Based on the received registration data, the FIMS registers the FDIE to be managed by itself. + +Each FDIE continuously monitors the status of fire related devices within the building and transmits the corresponding status data to the FIMS. After analysing the status data from the FDIEs, the FIMS determines whether any unusual conditions exist for each FDIE, such as malfunctioning of fire-related devices, etc. If there are no unusual conditions detected for the FDIE, the FIMS reports the analysis data to the firefighting infrastructure management service provider. + +![Sequence diagram showing the workflow of the FIMS in case of FDIE registration and management. The diagram involves three lifelines: FDIEs, FIMS, and Firefighting infrastructure management service provider. The process includes registration, status monitoring, analysis, and reporting.](cfef993dcc8fb513de79eb1f93cf26ae_img.jpg) + +``` + +sequenceDiagram + participant FDIEs + participant FIMS + participant FIMP as Firefighting infrastructure management service provider + + Note left of FDIEs: Register fire related devices in building + Note left of FDIEs: Generate the FDIE registration data + FDIEs->>FIMS: Transmit registration data for the FDIE + Note right of FIMS: Register the FDIE + FIMS-->>FDIEs: Ack of registration + + Note left of FDIEs: Monitor fire related device status + FDIEs->>FIMS: Transmit status data for the FDIE + Note right of FIMS: Analyse status data for the FDIEs + Note right of FIMS: Determine no unusual condition for the FDIEs + FIMS-->>FDIEs: Ack of receiving + FIMS->>FIMP: Report analysis data for the FIMS + FIMP-->>FIMS: Ack of receiving + +``` + +Legend: Action    Data    L.1631(23) + +Sequence diagram showing the workflow of the FIMS in case of FDIE registration and management. The diagram involves three lifelines: FDIEs, FIMS, and Firefighting infrastructure management service provider. The process includes registration, status monitoring, analysis, and reporting. + +**Figure 3 – The workflow of the FIMS in case of FDIE registration and management** + +### 8.2 Use case for unusual condition detection + +Figure 4 shows the workflow of the FIMS in case of detecting unusual conditions in FDIEs. Each FDIE monitors their fire-related device status and transmits the corresponding status data to the FIMS. The FIMS analyses the received data and determines whether the condition for each FDIE is unusual, such as the malfunctioning of fire-related devices, etc. If an unusual condition is detected for one or more FDIEs, the FIMS notifies the FDIEs about the unusual condition and reports the malfunctioning of the FDIEs to the firefighting infrastructure management service provider. The FIMS waits for an acknowledgement from the service provider. The FDIEs, upon receiving the notification, identify the location of the unusual condition and attempt to fix it. Once the FDIEs have addressed the unusual condition and achieved recovery, the FIMS verifies the recovery and reports the recovery confirmation to the service provider. The FIMS awaits acknowledgement from the service provider upon reporting the recovery confirmation. + +![Sequence diagram showing the workflow of the FIMS in case of detecting unusual conditions in FDIE. The diagram involves three lifelines: FDIEs, FIMS, and Firefighting infrastructure management service provider. The process starts with FDIEs monitoring device status, transmitting data to FIMS, which then analyses it and determines no unusual condition. FIMS notifies FDIEs, who acknowledge. FDIEs then identify the location and fix the condition, transmitting recovery confirmation to FIMS, which confirms recovery and reports to the service provider, receiving acknowledgements at each step.](d4af765160d04ecef538e5066006dc77_img.jpg) + +``` + +sequenceDiagram + participant FDIEs + participant FIMS + participant FIMP as Firefighting infrastructure management service provider + + Note left of FDIEs: Monitor the fire related device status + FDIEs->>FIMS: Transmit status data for the FDIE + Note right of FIMS: Analyse status data for the FDIE + Note right of FIMS: Determine no unusual condition for the FDIE + FIMS->>FDIEs: Notify the unusual condition + FDIEs->>FIMS: Ack of receiving + FIMS->>FIMP: Report the analysis data for the FIMSs + FIMP->>FIMS: Ack of receiving + Note left of FDIEs: Identify the location of the unusual condition + Note left of FDIEs: Fix the unusual condition + FDIEs->>FIMS: Transmit the recovery confirmation + Note right of FIMS: Confirm the recovery for the FDIE + FIMS->>FIMP: Report the recovery confirmation for the FIMS + FIMP->>FIMS: Ack of receiving + FIMS->>FDIEs: Ack of receiving + +``` + +└ Action      → Data    L.1631(23) + +Sequence diagram showing the workflow of the FIMS in case of detecting unusual conditions in FDIE. The diagram involves three lifelines: FDIEs, FIMS, and Firefighting infrastructure management service provider. The process starts with FDIEs monitoring device status, transmitting data to FIMS, which then analyses it and determines no unusual condition. FIMS notifies FDIEs, who acknowledge. FDIEs then identify the location and fix the condition, transmitting recovery confirmation to FIMS, which confirms recovery and reports to the service provider, receiving acknowledgements at each step. + +**Figure 4 – The workflow of the FIMS in case of detecting unusual conditions in FDIE** + +### 8.3 Use case for emergency recovery request + +Figure 5 shows the workflow of the FIMS in case of an emergency recovery request. When a fire signal is detected, the FDIE identifies the location of the fire signal and generates a set of data for it. The FDIE then transmits the set of data to the FIMS and awaits acknowledgement. The FIMS analyses the received set of data for the fire signal and determines whether the fire accident has occurred. Upon confirming the occurrence of the fire accident, the FIMS initiates an emergency recovery request and waits for an acknowledgement. If the severity of the fire accident is high, the FIMS directly requests emergency recovery assistance from the firefighting station with the relevant set of data. After analysing the emergency recovery situation, the FIMS reports both the fire accident and the emergency recovery situation to the firefighting safety management organization via the city management interface. The FIMS awaits acknowledgement from the firefighting safety management organization upon reporting. + +![Sequence diagram showing the workflow of the FIMS in case of an emergency recovery request. Lifelines: FDIEs, FIMS, Firefighting station, Firefighting safety management organization. The process involves signal detection, data transmission, analysis, and emergency recovery requests with acknowledgements.](af7916c89a458fdab6c3f443217388ae_img.jpg) + +``` + +sequenceDiagram + participant FDIEs + participant FIMS + participant FS as Firefighting station + participant FMO as Firefighting safety management organization + + Note left of FDIEs: Detect a fire signal + Note left of FDIEs: Identify the location of the fire signal + Note left of FDIEs: Generate the set of data for the fire signal + FDIEs->>FIMS: Transmit the set of data for the fire signal + FIMS-->>FDIEs: Ack of receiving + Note right of FIMS: Analyse the set of data for the fire signal + Note right of FIMS: Determine whether or not the fire accident is occurred + FIMS->>FS: Request the emergency recovery + Note left of FDIEs: Alert the fire accident to fire alarm devices and sprinkler + FDIEs-->>FIMS: Ack of receiving + FS-->>FIMS: Ack of receiving + Note right of FIMS: Analyse the emergency recovery situation + FIMS->>FMO: Report analysis data for emergency recovery situation + FMO-->>FIMS: Ack of receiving + +``` + +Legend: Action (solid line with arrowhead), Data (solid line with arrowhead). L.1631(23) + +Sequence diagram showing the workflow of the FIMS in case of an emergency recovery request. Lifelines: FDIEs, FIMS, Firefighting station, Firefighting safety management organization. The process involves signal detection, data transmission, analysis, and emergency recovery requests with acknowledgements. + +**Figure 5 – The workflow of the FIMS in case of an emergency recovery request** + +### 8.4 Use case for emergency recovery cancellation + +Figure 6 shows the workflow of the FIMS in case of an emergency recovery cancellation. When a fire signal is detected, the FDIE identifies the location of the fire signal and generates a set of data for it. The FDIE transmits the set of data to the FIMS and awaits acknowledgement. The FIMS analyses the received set of data for the fire signal and determines whether a fire accident has not occurred. If the FIMS determines that the fire accident has not occurred, it requests an emergency recovery cancellation from the FDIE and waits for an acknowledgement. + +![Sequence diagram showing the workflow of FIMS in case of emergency recovery cancellation between FDIEs and FIMS.](4801720824e4b5e2361a5564f91cfb70_img.jpg) + +``` + +sequenceDiagram + participant FDIEs + participant FIMS + Note left of FDIEs: Detect a fire signal + Note left of FDIEs: Identify the location of the fire signal + Note left of FDIEs: Generate the set of data for the fire signal + FDIEs->>FIMS: Transmit the set of data for the fire signal + FIMS-->>FDIEs: Ack of receiving + Note right of FIMS: Analyse the set of data for the fire signal + Note right of FIMS: Determine whether or not the fire accident is occurred + FIMS-->>FDIEs: Request the emergency cancellation + Note left of FDIEs: Cancel the fire signal + FDIEs->>FIMS: Ack of receiving + +``` + +The diagram illustrates the interaction between FDIEs and FIMS for emergency recovery cancellation. The sequence of events is as follows: + + +- FDIEs perform internal actions: "Detect a fire signal", "Identify the location of the fire signal", and "Generate the set of data for the fire signal". +- FDIEs send a message "Transmit the set of data for the fire signal" to FIMS. +- FIMS responds with "Ack of receiving". +- FIMS performs internal actions: "Analyse the set of data for the fire signal" and "Determine whether or not the fire accident is occurred". +- FIMS sends a "Request the emergency cancellation" message to FDIEs. +- FDIEs perform the internal action "Cancel the fire signal". +- FDIEs send an "Ack of receiving" message back to FIMS. + + A legend at the bottom indicates that a solid line with an arrow represents an "Action" and a dashed line represents "Data". The reference "L.1631(23)" is noted at the bottom right. + +Sequence diagram showing the workflow of FIMS in case of emergency recovery cancellation between FDIEs and FIMS. + +**Figure 6 – The workflow of the FIMS in case of emergency recovery cancellation** + +## Bibliography + +- [b-ITU-T L.1630] Recommendation ITU-T L.1630 (2023), *Framework of a building infrastructure management system for sustainable cities*. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| 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b/marked/L/T-REC-L.1632-202408-I_PDF-E/raw.md @@ -0,0 +1,550 @@ + + +# Recommendation + +## **ITU-T L.1632 (08/2024)** + +SERIES L: Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant + +Circular and sustainable cities and communities + +--- + +## **Identification method for building infrastructure equipment in a sustainable city** + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with white lines representing latitude and longitude, and the letters 'ITU' in a bold, blue, sans-serif font superimposed on the globe. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +### **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|--------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| Infrastructure including node elements (except cables) | L.200-L.249 | +| General aspects and network design | L.250-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| Optical fibre cable maintenance | L.300-L.329 | +| Infrastructure maintenance | L.330-L.349 | +| Operation support and infrastructure management | L.350-L.379 | +| Disaster management | L.380-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1632 + +## Identification method for building infrastructure equipment in a sustainable city + +## Summary + +Buildings are one of the major key city assets and it is important to effectively and easily manage building infrastructure in order to realize a sustainable city. A number of pieces of equipment exist at building infrastructures, and building infrastructure management systems are separately utilized for dedicated infrastructure management services in terms of efficiency, safety and sustainability. Buildings may have different management systems depending on the type of facility, such as firefighting management systems, energy management systems, electrical safety management systems and building automation systems. The different management systems use the separate identification method, so the different methods may cause inefficiency and inconvenience for managing the many pieces of equipment at the building. In order to realize a sustainable city, it is important to efficiently manage a number of pieces of equipment within a city. By allocating identifiers to the equipment in buildings, the city asset management system in a sustainable city can improve their manageability. + +Recommendation ITU-T L.1632 defines the identification method for equipment at the building infrastructure which improves the manageability and interworking between facilities at the building. The identification method includes the identifier structure and identifier management procedure which are easily recognizable, understandable mapping between identifier and device, and consistency in the equipment category. The identification method defined in this Recommendation is used within a building infrastructure and can be operated in conjunction with the city-level identification system that uniquely identifies the city assets such as buildings, energy resources, etc. Therefore, it can help realize a sustainable city. + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.1632 | 2024-08-29 | 5 | 11.1002/1000/16001 | + +## Keywords + +Building, building infrastructure, identification, management system, sustainable city. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, and information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2024 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|---------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere..... | 1 | +| 3.2 Terms defined in this Recommendation ..... | 2 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 2 | +| 6 Overview of building infrastructure management system..... | 2 | +| 7 Identification method for building equipment ..... | 5 | +| 8 Operation procedures of identification method..... | 6 | +| 8.1 Overview ..... | 6 | +| 8.2 Procedure for allocating an equipment identifier ..... | 7 | +| 8.3 Procedure for updating an equipment identifier..... | 8 | +| 8.4 Procedure for deleting an equipment identifier..... | 8 | +| Appendix I – Equipment identifier examples for firefighting infrastructure..... | 9 | +| I.1 Code examples for firefighting equipment..... | 9 | +| I.2 Example codes for location of equipment..... | 10 | +| I.3 Examples of identifiers for firefighting infrastructure in a building ..... | 10 | +| Bibliography ..... | 13 | + + + +# Recommendation ITU-T L.1632 + +## Identification method for building infrastructure equipment in a sustainable city + +## 1 Scope + +This Recommendation describes a specification of an identification method for building infrastructure equipment at the building infrastructure as follows: + +- overview of the building infrastructure management system; +- identification method for the building equipment; +- operational procedures of the identification method. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T L.1630] Recommendation ITU-T L.1630 (2023), *Framework of a building infrastructure management system for sustainable city*. + +## 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 energy equipment** [ITU-T L.1630]: An individual item of equipment consisting of an energy infrastructure and classified as energy receiving equipment and energy distribution equipment. + +**3.1.2 energy infrastructure** [ITU-T L.1630]: A set of equipment that receives various types of energy such as electricity, gas and water from the energy providers and distributes the energy to the building infrastructure. + +**3.1.3 energy infrastructure management** [ITU-T L.1630]: A function that supports the operation of energy equipment and communication using a data model and provides an intelligent energy equipment management service. + +**3.1.4 fire detection and identifying equipment** [b-ITU-T L.1631]: Equipment that generates a set of fire-related data and sends it to the firefighting infrastructure management system (FIMS). + +**3.1.5 firefighting equipment** [ITU-T L.1630]: An individual equipment consists of a firefighting infrastructure, and is classified as communication-less legacy firefighting equipment and communication capable firefighting equipment. + +**3.1.6 firefighting infrastructure** [ITU-T L.1630]: A set of equipment that protects or evacuates people by detecting and notifying fires, enables immediate firefighting activities at the early stage of a fire, and extinguishes fires by automatic or manual operation. + +**3.1.7 firefighting infrastructure management** [ITU-T L.1630]: A function that supports the operation of fire alarm control equipment and the communication using data model and provides the intelligent firefighting equipment management service. + +**3.1.8 firefighting infrastructure management system** [b-ITU-T L.1631]: A system that manages one or more FDIE(s) and supports effective response through coordination with firefighting infrastructure management service providers and firefighting stations. + +### **3.2 Terms defined in this Recommendation** + +None. + +## **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|-----------------------------------------------| +| AES | Automatic Extinguishing System | +| ASS | Auto Section Switch | +| BIMS | Building Infrastructure Management System | +| CP | Control Panel | +| DB | Database | +| EEI | Electrical Energy Infrastructure | +| EIMS | Energy Infrastructure Management System | +| ENI | Environment Infrastructure | +| EvIMS | Environment Infrastructure Management System | +| FDIE | Fire Detection and Identifying Equipment | +| FFI | Firefighting Infrastructure | +| FIMS | Firefighting Infrastructure Management System | +| GEI | Gas Energy Infrastructure | +| HVAC | Heating, Ventilation and Air Conditioning | +| ID | Identifier | +| OID | Object Identifier | +| PCS | Power Conditioning System | +| PV | Photovoltaics | +| UI | User Interface | +| WEI | Water Energy Infrastructure | + +## **5 Conventions** + +None. + +## **6 Overview of building infrastructure management system** + +A building infrastructure is typically composed of energy equipment, firefighting equipment and environmental equipment. The building infrastructure management system (BIMS) defined in [ITU-T L.1630] provides the common functions, equipment management functions and application-specific services. The application service providers for the three types of building equipment communicate with BIMS through the service interfaces. The application service providers can be connected to the city-level infrastructure management system through the city management interfaces. The city management organizations can interact with BIMS in each building, such as + +public buildings, through the city management interfaces. However, in most cases, the application service providers manage many buildings, so the city management organizations interact with the application service providers. + +The conceptual overview of BIMS depicted in Figure 1 is based on [ITU-T L.1630] and revised. Since there are many pieces of equipment in a building and there exists a lot of buildings in a city, it is important to uniquely identify the equipment. The equipment management function in BIMS has an identification method to generate an identifier for equipment, and allocate, update and delete it. + +![Figure 1: Overview of building infrastructure management system (BIMS) and the related entities for buildings in sustainable cities. The diagram shows the flow of information from in-building infrastructure through BIMS to city management organizations via various interfaces.](562f471e8153729557e6a4ee6343c32c_img.jpg) + +The diagram illustrates the architecture of a Building Infrastructure Management System (BIMS) and its interactions. At the top, three boxes represent service providers: 'Environment infrastructure management system service provider', 'Energy infrastructure management system service provider', and 'Firefighting infrastructure management system service provider'. These are connected to a central 'Service interface' (dashed box). Below this, a large box labeled 'In-building infrastructure' contains 'Energy equipment', 'Firefighting equipment', and 'Environment equipment' connected to a 'Building local network' (cloud). This network is connected to the 'BIMS (Building infrastructure management system)' box. The BIMS box contains 'Application specific service function', 'Equipment management function', and 'Platform common function', which are further connected to a 'Security and platform management function'. The BIMS is connected to a 'City management interface' (dashed box), which in turn connects to three city-level organizations: 'City energy management organization', 'City firefighting safety management organization', and 'City environment management organization'. A large arrow labeled 'City management interface' also points from the service providers at the top to these city-level organizations. The label 'L.1632(24)' is in the bottom right corner. + +Figure 1: Overview of building infrastructure management system (BIMS) and the related entities for buildings in sustainable cities. The diagram shows the flow of information from in-building infrastructure through BIMS to city management organizations via various interfaces. + +**Figure 1 – Overview of building infrastructure management system (BIMS) and the related entities for buildings in sustainable cities** + +The building infrastructure provides visualization services through user interfaces to the administrators. The visualization services offer the building infrastructure information such as monitoring, control, alarm and fault data to the building administrators via a web service or mobile apps. To facilitate the easy recognition of equipment, the information utilizes identifiers as an index for this. + +Buildings may have different management systems depending on the type of facility, such as firefighting management systems, energy management systems, electrical safety management systems and building automation systems. These diverse management systems may use separate identification methods, so the different methods may cause inefficiency and inconvenience for managing the many pieces of equipment in the building. + +To address this issue, it is recommended that the identifier should be configured using the same scheme for all types of equipment in the building infrastructure. It can incorporate the equipment characteristics, such as type, location and function, to ensure easy recognition, understandable mapping to equipment and consistency in its categories. + +Table 1 illustrates the equipment installed in the building, describing its features. As shown in Table 1, a building comprises various types of facilities for environmental control, energy management and firefighting, each composed of one or more pieces of equipment. + +**Table 1 – Examples of equipment in building infrastructure** + +| Type | Facility (system) | Description | Equipment | +|-------------------|----------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------| +| Environment | HVAC system | Heating, ventilation, and air conditioning (HVAC) is the use of various technologies to control the temperature, humidity and purity of the air in an enclosed space. | Chiller, heater, pump, fan, duct, cooling tower, valve | +| Electrical energy | Electrical supply facility | A facility for receiving electricity from a utility company and distributing electricity within a building | Transformer, circuit breaker, switch, relay, cable | +| | Renewable energy facility | A facility for the production of electrical energy that utilizes a renewable generation resource (solar, geothermal) | PV (photovoltaics) panel, PCS, steam turbine, pump | +| Water energy | Water supply facility | A facility for receiving water from a utility company and distributing water within a building | Pump, water storage, valve, pipe | +| Gas energy | Gas supply facility | A facility for receiving gas from a utility company and distributing gas within a building | Pipe, valve | +| Firefighting | Fire detection and alarm systems | A facility for extinguishing fires or protecting the user from fire | Fire detector, alarm device, sprinkler | +| | Fire sprinkler system | A type of automatic extinguishing system (AES) that prevents fire growth and spread by releasing water through a series of sprinkler heads connected to a distribution piping system. | Valve, sprinkler head, pipe, water storage container | + +To enable data communication functions, a controller is necessary either inside or outside the equipment. In cases where the equipment lacks a built-in controller, a sensor or actuator should be installed on the equipment to acquire real-time data. A control panel features an interface for online data communication functions and allows local data checking through a display for a facility. It can acquire data from equipment of the facility and exchange it with a management system. Table 2 provides examples of devices with communication capabilities in building infrastructure. + +**Table 2 – Examples of device with data communication function** + +| Type | Example | +|---------------|-------------------------------------------------------------------------------------------------------------------------------------------------| +| Sensor | Electrical/gas/flow meter, temperature sensor, humidity sensor, gas (ex: hydrogen gas, carbon dioxide) sensor, dust sensor, pressure gauge etc. | +| Actuator | Valve actuator, fan actuator | +| Controller | Relay, ASS controller, PCS, convertor controller | +| Control panel | Coolant system CP, HVAC CP, fire alarm CP | + +An identifier should be assigned to all equipment and devices installed in the building, incorporating their features. Once these items are deployed within a building, they are registered in BIMS using an index as the identifier. If any of these items are subsequently removed, their identifier should be deleted from the system. + +## 7 Identification method for building equipment + +A building has an energy facility, firefighting facility and environmental facility, and these facilities are composed of various equipment. A building administrator manages and operates the equipment through BIMS and the equipment identifiers (IDs) are used for equipment recognition. To ensure efficient equipment management, a standardized identification scheme should be used and the identifiers should be structured in order for administrators to easily recognize the characteristics of the equipment. Thus, the identifiers for building equipment are defined according to the structure in Figure 2. + +![Figure 2: Structure of identifier for building equipment in sustainable cities. The diagram shows a hierarchical structure. At the top level, there are three boxes: 'Building ID', 'Infrastructure type', and 'Equipment information'. Below 'Equipment information', there is a line that branches into three boxes: 'Facility (System) name', 'Equipment name', and 'Location'. A small label 'L.1632(24)' is at the bottom right.](e9314c83043183351ed74908e9bf2f90_img.jpg) + +Figure 2: Structure of identifier for building equipment in sustainable cities. The diagram shows a hierarchical structure. At the top level, there are three boxes: 'Building ID', 'Infrastructure type', and 'Equipment information'. Below 'Equipment information', there is a line that branches into three boxes: 'Facility (System) name', 'Equipment name', and 'Location'. A small label 'L.1632(24)' is at the bottom right. + +**Figure 2 – Structure of identifier for building equipment in sustainable cities** + +- Building ID is the identifier for distinguishing buildings within the city and has to be assigned a globally unique value. For example, it can be represented in object identifier (OID) format. The infrastructure type and equipment information of Figure 2 are used locally within a building, and equipment identifier with a unique building ID is unique in the city. How to make a building ID is not in scope for this Recommendation. +- Infrastructure type is a field used to categorize various infrastructures within a building. BIMS for the same type of facility, for example EIMS, FIMS and EvIMS, can be operated. + +**Table 3 – Code examples for infrastructure type** + +| Infrastructure type | Code example | +|----------------------------------|--------------| +| Firefighting infrastructure | FFI | +| Environment infrastructure | ENI | +| Electrical energy infrastructure | EEI | +| Water energy infrastructure | WEI | +| Gas energy infrastructure | GEI | + +- Equipment information consists of the following three elements. + - Facility name: represented by a standardized code that indicates the name of the facility or system to which the equipment belongs. The standardization of the code is out of scope but examples of that code are provided in Appendix I. + - Equipment name: represented by a standardized code that indicates the name of the equipment. The standardization of the code is out of scope but examples of that code are provided in Appendix I. + - Location: represented by a standardized code that indicates the equipment location within a building. The standardization of methods for representing equipment locations within the building is out of scope but examples of the method are provided in Appendix I. + +## 8 Operation procedures of identification method + +### 8.1 Overview + +A building equipment should be registered and managed in BIMS, when it is installed in a building. Figure 3 shows the functional entities for managing equipment identifiers in functions of BIMS. The system administrator can register the equipment deployed in the building into BIMS through the UI for the equipment setting functional entity. The identifier management entity in the equipment management function supports the capability to allocate, update and delete identifiers for equipment. A database system in the platform common function stores the equipment's data using the identifier as index. The data management entity identifies equipment messages by its identifiers when communicating with building equipment using communication protocols. + +![Diagram of entities for managing an equipment identifier in BIMS](27b06ec9f42b5d727a2630f61a5f1861_img.jpg) + +The diagram illustrates the architecture for managing equipment identifiers. On the left, 'In-building infrastructure' includes 'Energy equipment', 'Firefighting equipment', and 'Environment equipment' connected to a 'Building local network' cloud. This network connects to the 'BIMS (Building infrastructure management system)'. The BIMS is divided into three horizontal functional layers: 'Application specific service function' (containing 'UI for equipment setting'), 'Equipment management function' (containing 'Identifier management entity'), and 'Platform common function' (containing 'Data management entity' and 'Identifier based DB'). A vertical 'Security and platform management function' bar is on the right side of the BIMS box. A small label 'L.1632(24)' is at the bottom right. + +Diagram of entities for managing an equipment identifier in BIMS + +**Figure 3 – Entities for managing an equipment identifier in BIMS** + +In Figure 4, the identifier management entity performs the function to allocate, update and delete identifiers. When an equipment is deployed in a building and registered on the BIMS by a system administrator's command, the identifier management entity receives a request message from the deployed equipment. It then allocates a unique identifier, sends a response message with the identifier back to the equipment and stores the identifier and equipment information in a database. If equipment information needs to be updated, the identifier management entity allocates a new identifier, sends request message with it to the equipment and updates the database upon receiving a confirmation response. When an equipment installer deletes equipment, the identifier management entity deletes the identifier and equipment information from the database. The identifier and equipment information may be backed up according to the operating policy. By allocating identifiers to the equipment in buildings, the city asset management system in a sustainable city can improve their manageability. + +![Flowchart of the identifier management entity in BIMS. The process starts with 'Start', followed by 'Receive cmd from UI (By administrator)'. It then enters a loop of decision diamonds: 'Register an equipment?', 'Update an equipment?', and 'Delete an equipment?'. Each 'Yes' path leads to a specific action: 'Receive req msq for ID from the equipment', 'Updating ID of the equipment', or 'Delete or backup the ID and information on DB'. The 'Register' path includes a decision 'Is there the equipment in the list?'. If 'No', it loops back to 'Receive req msq for ID from the equipment'. If 'Yes', it proceeds to 'Send rsp msg with allocated ID' and 'Store ID and information of the equipment to DB'. The 'Update' path includes a decision 'Rsp msg is OK?'. If 'No', it loops back to 'Send req msg with new ID to the equipment'. If 'Yes', it proceeds to 'Update ID on DB'. A legend on the right defines cmd: command, req: request, rsp: response, msg: message. The code L.1632(24) is at the bottom right.](af7916c89a458fdab6c3f443217388ae_img.jpg) + +``` + +graph TD + Start([Start]) --> ReceiveCmd[Receive cmd from UI +(By administrator)] + ReceiveCmd --> Register{Register an equipment?} + Register -- No --> Update{Update an equipment?} + Update -- No --> Delete{Delete an equipment?} + Delete -- No --> Register + Register -- Yes --> ReqID[Receive req msq for ID +from the equipment] + ReqID --> IsList{Is there the equipment in the list?} + IsList -- No --> ReqID + IsList -- Yes --> RspID[Send rsp msg with allocated ID] + RspID --> StoreID[Store ID and information of the equipment to DB] + StoreID --> ReceiveCmd + Update -- Yes --> UpdateID[Updating ID of the equipment] + UpdateID --> ReqNewID[Send req msg with new ID to the equipment] + ReqNewID --> RspOK{Rsp msg is OK?} + RspOK -- No --> ReqNewID + RspOK -- Yes --> UpdateDB[Update ID on DB] + UpdateDB --> ReceiveCmd + Delete -- Yes --> DeleteDB[Delete or backup the ID and information on DB] + DeleteDB --> ReceiveCmd + +``` + +cmd: command +req: request +rsp: response +msg: message +L.1632(24) + +Flowchart of the identifier management entity in BIMS. The process starts with 'Start', followed by 'Receive cmd from UI (By administrator)'. It then enters a loop of decision diamonds: 'Register an equipment?', 'Update an equipment?', and 'Delete an equipment?'. Each 'Yes' path leads to a specific action: 'Receive req msq for ID from the equipment', 'Updating ID of the equipment', or 'Delete or backup the ID and information on DB'. The 'Register' path includes a decision 'Is there the equipment in the list?'. If 'No', it loops back to 'Receive req msq for ID from the equipment'. If 'Yes', it proceeds to 'Send rsp msg with allocated ID' and 'Store ID and information of the equipment to DB'. The 'Update' path includes a decision 'Rsp msg is OK?'. If 'No', it loops back to 'Send req msg with new ID to the equipment'. If 'Yes', it proceeds to 'Update ID on DB'. A legend on the right defines cmd: command, req: request, rsp: response, msg: message. The code L.1632(24) is at the bottom right. + +Figure 4 – Processing flow of the identifier management entity in BIMS + +### 8.2 Procedure for allocating an equipment identifier + +Figure 5 shows the procedure for allocating an identifier to building equipment. The identifiers should be registered and managed in BIMS. First, a system administrator inputs the list of planned equipment through the UI for equipment setting and an equipment installer installs all of the equipment in the list. The identifier management entity generates identifiers for the equipment according to the identification method defined in clause 7. The equipment requests and receives its identifier from the identifier management entity after it is connected with BIMS. Then, the identifier management entity stores the identifier and information for the equipment to a database. The data management entity communicates with the building equipment and stores and manages data from the equipment using the identifiers in the database. + +![Sequence diagram showing the procedure for allocating an equipment identifier. It involves three main actors: Equipment installer, Building equipment, and BIMS (containing UI for equipment setting, Identifier management entity, Data management entity, and Identifier based DB). The steps are: (1) System administrator inputs the list of equipment to the UI; (2) Equipment installer installs the equipment; (3) Building equipment requests an identifier from the Identifier management entity; (4) Identifier management entity allocates an identifier to the Building equipment; (5) Identifier management entity adds the identifier and information for the equipment to the Identifier based DB; (6) Data management entity inputs or outputs data based on the identifier. A dashed line labeled 'Data communication' connects the Building equipment and the Data management entity. The code L.1632(24) is at the bottom right.](cab0834804fb031b43865554cc8d06ab_img.jpg) + +``` + +sequenceDiagram + actor EI as Equipment installer + actor BE as Building equipment + subgraph BIMS + UI[UI for equipment setting] + IME[Identifier management entity] + DME[Data management entity] + IDB[(Identifier based DB)] + end + SA[System administrator] + Note right of SA: (1) Input the list of equipment + UI --> IME + Note left of EI: (2) Install the equipment + BE --> IME: (3) Request identifier + IME --> BE: (4) Allocate identifier + IME --> IDB: (5) Add identifier and information for equipment + Note left of DME: (6) Input or output data based identifier + DME --> IDB + BE-->>DME: Data communication + +``` + +L.1632(24) + +Sequence diagram showing the procedure for allocating an equipment identifier. It involves three main actors: Equipment installer, Building equipment, and BIMS (containing UI for equipment setting, Identifier management entity, Data management entity, and Identifier based DB). The steps are: (1) System administrator inputs the list of equipment to the UI; (2) Equipment installer installs the equipment; (3) Building equipment requests an identifier from the Identifier management entity; (4) Identifier management entity allocates an identifier to the Building equipment; (5) Identifier management entity adds the identifier and information for the equipment to the Identifier based DB; (6) Data management entity inputs or outputs data based on the identifier. A dashed line labeled 'Data communication' connects the Building equipment and the Data management entity. The code L.1632(24) is at the bottom right. + +Figure 5 – Procedure for allocating an equipment identifier + +### 8.3 Procedure for updating an equipment identifier + +An equipment identifier can be updated as shown in Figure 6, since its information, such as the installation location, can be changed. The system administrator updates the information of equipment through the UI for equipment setting. The identifier management entity generates updated identifiers for the equipment. It sends the identifier update request to the equipment and confirms its update. Then, the identifier management entity updates the identifier for equipment in the database. The data management entity communicates with the building equipment, and stores and manages data from the equipment using the identifiers in the database. + +![Sequence diagram for updating an equipment identifier](4ee27dbf5ef12e7b58b0ef0937bc5a5e_img.jpg) + +This sequence diagram illustrates the procedure for updating an equipment identifier. The main components are the System administrator, BIMS (containing UI for equipment setting, Identifier management entity, Data management entity, and Identifier based DB), and Building equipment. The process starts with the System administrator sending (1) 'Update the equipment information' to the UI for equipment setting. The UI then sends (2) 'Request the identifier update' to the Identifier management entity. The Identifier management entity sends (3) 'Response the identifier update' to the Building equipment. Next, the Identifier management entity sends (4) 'Update the identifier in the DB' to the Identifier based DB. Finally, the Data management entity sends (5) 'Input or output data based identifier' to the Identifier based DB. A dashed arrow labeled 'Data communication' points from the Building equipment to the Data management entity. The diagram is labeled L.1632(24). + +Sequence diagram for updating an equipment identifier + +Figure 6 – Procedure for updating an equipment identifier + +### 8.4 Procedure for deleting an equipment identifier + +BIMS should delete the identifier assigned to uninstalled equipment according to the delete procedure in Figure 7. The system administrator deletes the identifier for removed equipment through the UI for equipment setting. Then, the identifier management entity deletes the identifier with its data or backs up the data for the equipment to the database. + +![Sequence diagram for deleting an equipment identifier](1b5a812c8aa20fd5cba28e97001d32de_img.jpg) + +This sequence diagram illustrates the procedure for deleting an equipment identifier. The main components are the Equipment installer, Building equipment, System administrator, and BIMS (containing UI for equipment setting, Identifier management entity, Data management entity, and Identifier based DB). The process starts with the Equipment installer sending (3) 'Remove the equipment' to the Building equipment. The System administrator sends (1) 'Delete the identifier for removed equipment' to the UI for equipment setting. The UI then sends (2) 'Delete the identifier for the equipment or backup its data' to the Identifier management entity. The Identifier management entity then interacts with the Data management entity and the Identifier based DB. The diagram is labeled L.1632(24). + +Sequence diagram for deleting an equipment identifier + +Figure 7 – Procedure for deleting an equipment identifier + +## Appendix I + +### Equipment identifier examples for firefighting infrastructure + +(This appendix does not form an integral part of this Recommendation.) + +### I.1 Code examples for firefighting equipment + +There are many types of firefighting facilities or systems, but this appendix provides the examples of codes for fire detection and alarm systems. Fire detection and alarm systems include equipment for fire detection, fire alarms and emergency broadcasting equipment. Table I.1 shows the equipment consisting of a fire detection and alarm system. + +**Table I.1 – Equipment for fire detection and alarm facility** + +| System | Equipment | Description | +|-------------------------------------------------|-------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Fire detection and identifying equipment (FDIE) | Fire detection control and indicating equipment | Equipment that generates a set of fire-related data and sends it to a firefighting infrastructure management system | +| | Manual fire alarm equipment | Equipment that manually transmits a fire signal to a fire detection control and indicating equipment | +| | Fire detector | Equipment with a detection function that detects physical and chemical changes that occur during a fire, a decision function that determines whether it is a fire or not, and a transmission function that transmits a fire signal to the fire detection control and indicating equipment. | +| | Audible alarm equipment | Equipment that signals an audible warning of fire to the occupants of a building. | +| | Visual alarm equipment | Equipment which generates a flashing light to signal to the occupants of a building that a fire alarm condition exists. | +| | Emergency broadcasting equipment | Equipment that automatically or manually broadcasts a voice or emergency warning about a fire situation through a loudspeaker. | + +The equipment name for firefighting equipment identifiers needs to include the functionality of the equipment. Table I.2 shows the example codes for equipment consisting of a fire detection and alarm system. + +**Table I.2 – Example code for equipment name in fire detection and alarm system** + +| Equipment | Name code | +|----------------------------------|-----------| +| Manual fire alarm equipment | MAD | +| Fire detector | FD | +| Audible alarm equipment | AAD | +| Visual alarm equipment | VAD | +| Emergency broadcasting equipment | BCE | + +### I.2 Example codes for location of equipment + +Table I.3 shows the example codes for classification of firefighting facility zones. + +**Table I.3 – Examples of firefighting facility zones** + +| Classification of firefighting facility zone | Code | +|----------------------------------------------|------| +| Fire detection and alarm zone | Zda | +| Smoke control zone | Zsc | +| Fire detection and water discharging zone | Zdd | +| Water discharging zone | Zwd | + +Table I.4 shows the example codes of the fire detection and alarm zones in a building. + +**Table I.4 – Example codes for fire detection and alarm zones in a building** + +| Classification | Type | Type code | Location code | +|----------------|-------------------------|-----------|---------------| +| Horizontal | Ground floor | FL | Number | +| | Underground floor | GR | Number | +| | Section | Sect | Alphanumeric | +| Vertical | Ground floor stair | ST | Number | +| | Underground floor stair | GST | – | +| | Elevator | EV | – | +| | Pipe duct | PDuct | – | + +### I.3 Examples of identifiers for firefighting infrastructure in a building + +Table I.5 shows the example building information. + +**Table I.5 – Example building information** + +| | | +|-------------------|--------------------------------------| +| Building location | Seoul, #15230 building | +| Floors | 1 Underground floor, 5 ground floors | +| Floor area | 900 m 2 | +| Etc. | Stairs, pipe duct, elevator | + +Table I.6 shows the information for firefighting equipment. + +**Table I.6 – Information for firefighting equipment** + +| Equipment | Configuration | +|-------------------------------------------------|--------------------------------------------------------------| +| Fire detection control and indicating equipment | Installed on the first underground floor | +| Heat detector | Connected to fire detection control and indicating equipment | +| Smoke detector | Connected to fire detection control and indicating equipment | +| Audible alarm equipment | Connected to fire detection control and indicating equipment | +| Emergency broadcasting equipment | Connected to fire detection control and indicating equipment | + +To separate distinct components, you can use "(period)" or "/", etc. In this appendix, "." is used in the description of example identifiers. Table I.10 shows the example identifiers for firefighting equipment on the first underground floor based on Table I.7, Table I.8 and Table I.9. + +**Table I.7 – Example of building identifier** + +| | | +|---------------------|-------------------------------------------------| +| Building identifier | Regional location+Building ID
Ex) 0200015230 | +|---------------------|-------------------------------------------------| + +**Table I.8 – Example code for firefighting infrastructure** + +| | | +|---------------------|------------------------------------| +| Infrastructure type | Fire Fighting Infrastructure (FFI) | +|---------------------|------------------------------------| + +**Table I.9 – Example codes for fire detection and alarm zone** + +| | | | +|------------|-------------------------|------------------------------------------------------------------------------------------------------------------------------------------| +| Horizontal | Ground floor | ZdaFL1SectA, ZdaFL1SectB
ZdaFL2SectA, ZdaFL2SectB
ZdaFL3SectA, ZdaFL3SectB
ZdaFL4SectA, ZdaFL4SectB
ZdaFL5SectA, ZdaFL5SectB | +| | Underground floor | ZdaGR1SectA, ZdaGR1SectB | +| Vertical | Ground floor stair | ZdaST1 | +| | Underground floor stair | ZdaGST1 | +| | Pipe duct | ZdaPDuct1 | + +**Table I.10 – Identifier examples for first underground floor equipment** + +| Identifier | Equipment name | +|-------------------------------------|----------------------------------| +| 0200015230.FFI.FDIE.BCE.ZdaGR1SectA | Emergency broadcasting equipment | +| 0200015230.FFI.FDIE.AAD.ZdaGR1SectA | Audible alarm equipment | +| 0200015230.FFI.FDIE.FD.ZdaGR1SectA | Fire detector | +| 0200015230.FFI.FDIE.FD.ZdaGR1SectB | Fire detector | + +## Bibliography + +- [b-ITU-T L.1631] Recommendation ITU-T L.1631 (2023), *Reference model of firefighting infrastructure management systems for buildings in sustainable cities.* +- [b-ISO 7240-1] ISO 7240-1 (2014), *Fire detection and alarm systems – Part 1: General and definitions.* +- [b-ISO 7240-2] ISO 7240-2 (2017), *Fire detection and alarm systems – Part 2: Fire detection control and indicating equipment.* + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1640-202402-I_PDF-E/0538daaa5583c23e17db3a12f2281a55_img.jpg b/marked/L/T-REC-L.1640-202402-I_PDF-E/0538daaa5583c23e17db3a12f2281a55_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..1761a7470e8a9e428785eb00e74296e25ebd9a42 --- /dev/null +++ b/marked/L/T-REC-L.1640-202402-I_PDF-E/0538daaa5583c23e17db3a12f2281a55_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:d5e42f1d16b75bfee442ee7219f85c74294e811f7de5183a80a7c9d1342b0ccd +size 7289 diff --git a/marked/L/T-REC-L.1640-202402-I_PDF-E/1c427123350e0e73e2a109b79069314b_img.jpg b/marked/L/T-REC-L.1640-202402-I_PDF-E/1c427123350e0e73e2a109b79069314b_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..d6202c23f7687cff2b7d1a9db2410478c99c4f99 --- /dev/null +++ b/marked/L/T-REC-L.1640-202402-I_PDF-E/1c427123350e0e73e2a109b79069314b_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:b63dca37c3efa2d2787f41a96a25b30f9108769f967ee44f4d880538937c0792 +size 114138 diff --git a/marked/L/T-REC-L.1640-202402-I_PDF-E/410562339ce067fdc6fa41940c118658_img.jpg b/marked/L/T-REC-L.1640-202402-I_PDF-E/410562339ce067fdc6fa41940c118658_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..69b064dc1366544f98b13c8a9d27a5adcd214dd1 --- /dev/null +++ b/marked/L/T-REC-L.1640-202402-I_PDF-E/410562339ce067fdc6fa41940c118658_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:bafee272568e39b67f534502c7fd92b966545da77c974d9e8bc7c4959a04c16c +size 104180 diff --git a/marked/L/T-REC-L.1640-202402-I_PDF-E/5b4e774d63e0e0ed73801a9247755e5f_img.jpg b/marked/L/T-REC-L.1640-202402-I_PDF-E/5b4e774d63e0e0ed73801a9247755e5f_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..b536dfe2ec75a8b8ed39feed17493fe85f0bc2ca --- /dev/null +++ b/marked/L/T-REC-L.1640-202402-I_PDF-E/5b4e774d63e0e0ed73801a9247755e5f_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:45ef18690ec0b81a8ae23c682eebdded2aedda0a9d305432f363676919d62fd1 +size 103413 diff --git a/marked/L/T-REC-L.1640-202402-I_PDF-E/7a0db9703b68b3d06cdaeefc084c0006_img.jpg b/marked/L/T-REC-L.1640-202402-I_PDF-E/7a0db9703b68b3d06cdaeefc084c0006_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..c9752150d497eec43c86f6e480c73c80f007dbd6 --- /dev/null +++ b/marked/L/T-REC-L.1640-202402-I_PDF-E/7a0db9703b68b3d06cdaeefc084c0006_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:da2adbf57a71aabb89d59226f73acb924966b458ecbcc8e12725e7bbe312799c +size 67827 diff --git a/marked/L/T-REC-L.1640-202402-I_PDF-E/a83ba9e3e2c1e21dd69953a7b09e45b4_img.jpg b/marked/L/T-REC-L.1640-202402-I_PDF-E/a83ba9e3e2c1e21dd69953a7b09e45b4_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..46223fc02b083cd7488ad7ae1958ec28a1778231 --- /dev/null +++ b/marked/L/T-REC-L.1640-202402-I_PDF-E/a83ba9e3e2c1e21dd69953a7b09e45b4_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:46ab3786e458a8a8d390063dbf7c4e1390ce07761626747e200e6ac5d5ef12cc +size 51007 diff --git a/marked/L/T-REC-L.1640-202402-I_PDF-E/raw.md b/marked/L/T-REC-L.1640-202402-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..a01ad03f78829a643a7798b7f91a70b944a73df0 --- /dev/null +++ b/marked/L/T-REC-L.1640-202402-I_PDF-E/raw.md @@ -0,0 +1,557 @@ + + +# Recommendation **ITU-T L.1640 (02/2024)** + +SERIES L: Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant + +Circular and sustainable cities and communities + +--- + +# **Methodology for dynamic monitoring and analysis of greenhouse gas emissions in cities** + +![ITU logo](0538daaa5583c23e17db3a12f2281a55_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with white lines representing latitude and longitude, and the letters 'ITU' in a bold, blue, sans-serif font overlaid on the globe. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +### **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|--------------------------------------------------------|----------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| Cable structure and characteristics | L.100-L.124 | +| Cable evaluation | L.125-L.149 | +| Guidance and installation technique | L.150-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| Infrastructure including node elements (except cables) | L.200-L.249 | +| General aspects and network design | L.250-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| Optical fibre cable maintenance | L.300-L.329 | +| Infrastructure maintenance | L.330-L.349 | +| Operation support and infrastructure management | L.350-L.379 | +| Disaster management | L.380-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.1640 + +# Methodology for dynamic monitoring and analysis of greenhouse gas emissions in cities + +## Summary + +Recommendation ITU-T L.1640 presents the necessary conditions for implementing near-real-time greenhouse gas (GHG) monitoring in cities, with updates provided shortly after data collection rather than instantly (real-time), to support the sustainable development strategy and planning of the city. Compared to existing research or standards, near-real-time greenhouse gas data in cities can present high temporal resolution characteristics of urban emissions (hourly or daily), enabling better identification of spatial and temporal hotspots. This can help city managers formulate more effective emission reduction policies. + +Recommendation ITU-T L.1640 presents the general principles on data collection, data processing, data fusion, and monitoring and analysing of GHG emissions of cities and outlines the different methodologies that are being developed: + +- Sources for near-real-time city data collection, and its processing and fusing. +- Key steps for city near-real-time GHG calculation and attribution analysis. +- Optimization strategy for city sustainable planning. + +## History\* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.1640 | 2024-02-22 | 5 | 11.1002/1000/15770 | + +## Keywords + +Attribution analysis, dynamic monitoring, GHG emission, optimization strategy. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2024 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|------|---------------------------------------------------------------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 3.1 | Terms defined elsewhere ..... | 2 | +| 3.2 | Terms defined in this Recommendation..... | 2 | +| 4 | Abbreviations and acronyms ..... | 2 | +| 5 | Conventions ..... | 3 | +| 6 | Method framework for dynamic monitoring and analysis of GHG emissions..... | 3 | +| 7 | GHG emission data collection ..... | 3 | +| 8 | GHG emission data processing..... | 6 | +| 9 | GHG emission data fusion..... | 7 | +| 10 | GHG emission calculation ..... | 8 | +| 11 | Attribution analysis of GHG emission data and optimization strategy for sustainable development of city..... | 8 | +| 11.1 | Emission sources analysis and attribution analysis ..... | 8 | +| 11.2 | Optimization strategy for sustainable development of city ..... | 9 | +| | Appendix I – Example of monitoring city-level CO 2 emissions from ground transportation in China ..... | 10 | +| I.1 | General procedure of the example..... | 10 | +| I.2 | Example of collecting city-level activity data ..... | 10 | +| I.3 | Example for data process and data fusion ..... | 11 | +| I.4 | Example for estimating daily GHG emissions in near-real-time ..... | 11 | +| | Appendix II – Alibaba Cloud's "Carbon Vision" platform showing city near-real-time GHG emissions (mocked data)..... | 13 | +| | Bibliography..... | 14 | + + + +# Recommendation ITU-T L.1640 + +## Methodology for dynamic monitoring and analysis of greenhouse gas emissions in cities + +# 1 Scope + +This Recommendation proposes to introduce the methodology for dynamic monitoring and analysis for greenhouse gas (GHG) emissions, including: + +- GHG emission data collection; +- GHG emission data processing; +- GHG emission data fusion; +- GHG emission data application including GHG emission calculation and analysis and GHG emission changes attribution analysis. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T L.1400] Recommendation ITU-T L.1400 (2023), *Overview and general principles of methodologies for assessing the environmental impact of information and communication technologies*. +- [ITU-T L.1410] Recommendation ITU-T L.1410 (2014), *Methodology for environmental life cycle assessments of information and communication technology goods, networks and services*. +- [ITU-T L.1420] Recommendation ITU-T L.1420 (2012), *Methodology for energy consumption and greenhouse gas emissions impact assessment of information and communication technologies in organizations*. +- [ITU-T L.1430] Recommendation ITU-T L.1430 (2013), *Methodology for assessment of the environmental impact of information and communication technology greenhouse gas and energy projects*. +- [ITU-T L.1440] Recommendation ITU-T L.1440 (2015), *Methodology for environmental impact assessment of information and communication technologies at city level*. +- [ITU-T L.1450] Recommendation ITU-T L.1450 (2018), *Methodologies for the assessment of the environmental impact of the information and communication technology sector*. +- [ISO 14064-1] ISO 14064-1:2006, *Greenhouse gases – Part 1: Specification with guidance at the organization level for quantification and reporting of greenhouse gas emissions and removals*. +- [ISO 14064-2] ISO 14064-2:2006, *Greenhouse gases – Part 2: Specification with guidance at the project level for quantification, monitoring and reporting of greenhouse gas emission reductions or removal enhancements*. + +- [ISO 14064-3] ISO 14064-3:2006, *Greenhouse gases – Part 3: Specification with guidance for the validation and verification of greenhouse gas assertions.* +- [ISO 14067] ISO 14067:2018 (E), *Greenhouse gases – Carbon footprint of products – Requirements and guidelines for quantification.* + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 greenhouse gases (GHGs)** [ITU-T L.1410]: For the purposes of this methodology, GHGs are the seven gases listed in the Kyoto Protocol: + +- carbon dioxide (CO2) +- methane (CH4) +- nitrous oxide (N2O) +- hydrofluorocarbons (HFCs) +- perfluorocarbons (PFCs) +- sulphur hexafluoride (SF6) +- nitrogen trifluoride (NF3) + +**3.1.2 near-real-time** [b-Zhu 1]: Computation activities provided shortly after data collection rather than instantly (real-time). + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 dynamic monitoring:** Monitoring and detecting the daily temporal and spatial variation of greenhouse gas (GHG) emission data using multi-source data. + +**3.2.2 continuous emission monitoring system (CEMS):** Total equipment necessary for the determination of greenhouse gas (GHG) emission rate using pollutant analyser measurements and a conversion equation, graph, or computer program to produce results in units of the applicable emission limitation or standard. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|---------|-----------------------------------------------| +| CEMS | Continuous Emission Monitoring System | +| EPA | United States Environmental Protection Agency | +| EU ETS | European Union Emissions Trading System | +| GHG | Greenhouse Gas | +| GIS | Geographic Information System | +| IEA | International Energy Agency | +| NILM | Non-intrusive Load Monitoring | +| OCO | Orbiting Carbon Observatory | +| SDGs | Sustainable Development Goals | +| TROPOMI | Tropospheric Monitoring Instrument | + +# 5 Conventions + +None. + +# 6 Method framework for dynamic monitoring and analysis of GHG emissions + +The method for dynamic monitoring and analysis of greenhouse gas (GHG) emissions can be divided into four parts: data collection, data processing, data fusion and application, is shown in Figure 1. Data collection refers to raw data collection, which includes traditional data collection and multiple sources of data collection. Data processing refers to raw data cleaning, filtering and normalization, which improves raw data quality and extracts emission-related information for further calculation. Data fusion refers to the combination of all the processed data and estimate missing data. Application refers to near-real-time GHG emission calculation and analysis, which enables GHG dynamic monitoring and timely attribution analysis for public management. + +![Flowchart of the Method Framework for dynamic monitoring and analysis of GHG emissions. The process consists of four main stages: Data collection, Data processing, Data fusion, and Application. Data collection includes satellite monitoring, CEMS, inventories, energy consumption, power generation, industrial production, road transportation, and residential consumption. Data processing involves cleaning, gap filling, and normalization. Data fusion involves alignment, association, and interpolation. Application involves emission calculation and attribution analysis.](7a0db9703b68b3d06cdaeefc084c0006_img.jpg) + +``` +graph LR; subgraph DC [Data collection]; DC1[Satellite monitoring]; DC2[Continuous emission monitoring system (CEMS)]; DC3[Greenhouse gas inventories]; DC4[Energy consumption statistics]; DC5[Power generation]; DC6[Industrial production]; DC7[Road transportation]; DC8[Residential consumption]; end; subgraph DP [Data processing]; DP1[Data cleaning]; DP2[Data gap filling]; DP3[Data normalization]; end; subgraph DF [Data fusion]; DF1[Data alignment]; DF2[Data association]; DF3[Data interpolation]; end; subgraph A [Application]; A1[GHG emission calculation]; A2[Attribution analysis and optimization strategy]; end; DC --> DP; DP --> DF; DF --> A; DP1 --> DP2 --> DP3; DF1 --> DF2 --> DF3; A1 --> A2; +``` + +L.1640(24) + +Flowchart of the Method Framework for dynamic monitoring and analysis of GHG emissions. The process consists of four main stages: Data collection, Data processing, Data fusion, and Application. Data collection includes satellite monitoring, CEMS, inventories, energy consumption, power generation, industrial production, road transportation, and residential consumption. Data processing involves cleaning, gap filling, and normalization. Data fusion involves alignment, association, and interpolation. Application involves emission calculation and attribution analysis. + +**Figure 1 – Method Framework for dynamic monitoring and analysis of GHG emissions** + +# 7 GHG emission data collection + +At the city level, GHG emissions can be categorized into various sectors based on their sources, such as power generation, industrial production, transportation, and residential heating. In some instances, direct measurement of GHG emissions is feasible through top-down approaches, such as the installation of continuous monitoring equipment at factory emission outlets or satellite monitoring of GHG emissions. However, these measurement methods are often limited by the prohibitive cost of monitoring equipment, or the high level of uncertainty associated with satellite monitoring. Therefore, GHG accounting in cities mostly relies on energy consumption statistics or other related proxy data to track and estimate emissions, following GHG accounting guidance developed by esteemed organizations such as the Intergovernmental Panel on Climate Change (IPCC) and GHG Protocol. + +Generally, the sources of city-level GHG emission data are shown in Table 1. + +**Table 1 – GHG emission data sources city-level** + +| Type | Potential sources | Frequency | Description for usage | +|----------------------------------------------|-------------------------------------------------------------|------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Satellite monitoring | Scientific communities | Days | Satellite monitoring can be used to obtain atmospheric greenhouse gas column concentrations, and combined with meteorological and other parameters, inverse models can be used to calculate greenhouse gas emissions from cities or factories. | +| Continuous emission monitoring system (CEMS) | Factories / Environment regulatory agencies | Minute(s) | Factories equipped with CEMS devices can obtain real-time greenhouse gas emissions from factory chimneys and report them to urban regulatory agencies in real-time. | +| Greenhouse gas inventories | Government/regulatory agencies | Quarter to Year | Cities regularly compile quarterly or annual greenhouse gas inventories, but there is generally a lag of more than one year. Due to the relatively authoritative data sources of greenhouse gas inventories, they can be used to correct historical greenhouse gas data for cities. | +| Energy consumption statistics | Statistical agencies | Month to Year | They can be used to calculate carbon emissions in cities by multiplying the city's energy consumption by the corresponding emission parameters according to inventory compilation guidelines such as IPCC or GHG Protocol. | +| Power generation | Public service sectors (power grid/companies) | Minute to Month | When fuel consumption statistics for the power sector are unavailable, fuel consumption for power generation can be estimated using electricity production data. | +| Industrial production | Industry association / Statistical agencies | Week to Month | When fuel consumption statistics for the industrial sector are unavailable, fuel consumption for industrial production can be estimated using industrial production data (such as industrial product output). | +| Road transportation | Transportation regulatory departments | Minute to Month | When fuel consumption statistics for the transportation sector are unavailable, fuel consumption for the transportation sector can be estimated using traffic volume or road congestion. | +| Residential consumption | Public service sectors (natural gas suppliers/smart meters) | Minute to Month | When natural gas consumption data is lacking, heating or cooling demand for residents can be estimated using temperature data. | + +Detailed information on the data sources is listed and shown in Figure 2. + +![Figure 2 – GHG emission data collection of the city. This is a 3D perspective diagram of a cityscape illustrating various data sources for greenhouse gas (GHG) emissions. On the left, a power plant is labeled 'Power generation' with an icon of a lightning bolt. Next to it, an industrial facility is labeled 'Industrial production' with an icon of a factory. A road with cars is labeled 'Road transportation' with a car icon. In the center, a city skyline is labeled 'Energy consumption statistics' with an icon of a line graph. To the right of the skyline, a building is labeled 'GHG inventories' with a clipboard icon. On the far right, a residential area is labeled 'Residential consumption' with a flame icon. Above the city, a satellite in space is labeled 'Satellite monitoring' with a satellite icon. At the top center, a 'Continuous emission monitoring system (CEMS)' is indicated by an icon of a document with a magnifying glass. Dashed lines connect these icons to specific locations on the ground: CEMS to the power plant and industrial facility; Energy consumption statistics to the city skyline; Road transportation to the road; GHG inventories to a building; and Residential consumption to the residential area. The satellite is shown monitoring the entire city from above. A small code 'L.1640(24)' is visible in the bottom right corner of the diagram area.](5b4e774d63e0e0ed73801a9247755e5f_img.jpg) + +Figure 2 – GHG emission data collection of the city. This is a 3D perspective diagram of a cityscape illustrating various data sources for greenhouse gas (GHG) emissions. On the left, a power plant is labeled 'Power generation' with an icon of a lightning bolt. Next to it, an industrial facility is labeled 'Industrial production' with an icon of a factory. A road with cars is labeled 'Road transportation' with a car icon. In the center, a city skyline is labeled 'Energy consumption statistics' with an icon of a line graph. To the right of the skyline, a building is labeled 'GHG inventories' with a clipboard icon. On the far right, a residential area is labeled 'Residential consumption' with a flame icon. Above the city, a satellite in space is labeled 'Satellite monitoring' with a satellite icon. At the top center, a 'Continuous emission monitoring system (CEMS)' is indicated by an icon of a document with a magnifying glass. Dashed lines connect these icons to specific locations on the ground: CEMS to the power plant and industrial facility; Energy consumption statistics to the city skyline; Road transportation to the road; GHG inventories to a building; and Residential consumption to the residential area. The satellite is shown monitoring the entire city from above. A small code 'L.1640(24)' is visible in the bottom right corner of the diagram area. + +**Figure 2 – GHG emission data collection of the city** + +- a) **Satellite monitoring:** Satellite monitoring is a remote sensing technique that uses satellite sensors to measure GHG concentrations in the atmosphere. These sensors can detect GHG signatures such as CO2, CH4, and N2O from space, providing a global view of GHG concentrations and their sources. One example of a satellite mission dedicated to GHG observation is the Orbiting Carbon Observatory (OCO) mission by NASA. The OCO satellite uses a spectrometer to measure the absorption of sunlight at different wavelengths, which can be used to determine carbon dioxide concentrations in the atmosphere. Other satellite missions that can provide complementary information on GHG emissions include the Tropospheric Monitoring Instrument (TROPOMI) on the European Space Agency's Sentinel-5P satellite, which can detect methane emissions from sources such as oil and gas facilities. +- b) **Continuous emission monitoring system (CEMS):** The CEMS is an approach to measuring GHG emissions that involves using real-time or near-real-time monitoring equipment installed at industrial facilities, power plants, or other stationary sources of emissions. These monitoring systems continuously measure and record emissions data, providing a more comprehensive and accurate picture of GHG emissions compared to periodic or occasional measurements. The data collected by CEMS can typically be accessed through government agencies responsible for regulating emissions from industrial facilities, such as the United States Environmental Protection Agency (EPA) or the European Union Emissions Trading System (EU ETS). These agencies generally maintain databases or online portals where the public can access data on emissions from regulated facilities. Additionally, some power companies or industrial facilities may publish their emissions data, including GHG emissions, on their websites or in sustainability reports. + +- c) Greenhouse gas inventory: Greenhouse gas inventories record information on the amount, composition, and location of greenhouse gas emissions and absorption caused by human activities. These inventories can be obtained through: + - i) Government-led organizations and compilations of greenhouse gas inventories, which are usually prepared and published on a regular basis by government departments such as administration, statistics, energy, and environmental protection. + - ii) Greenhouse gas inventory data regularly reported by companies to the government. +- d) Energy consumption statistics: + - i) Official energy consumption statistics published by government statistical agencies, usually on an annual or quarterly basis. + - ii) Energy consumption statistics collected and published by institutions such as the International Energy Agency (IEA) and the World Bank, usually on an annual or monthly basis. +- e) Power generation: Data on electricity production or consumption by source or end-use, regularly compiled and published by official electricity joint organizations or power generation companies, usually on a daily or hourly basis. +- f) Road transportation: Traffic flow data from road counting sensors or global positioning system (GPS) information records, or road traffic data such as traffic flow and road congestion indices estimated by map navigation vendors based on user location data, which can reflect road traffic flow information, usually on a daily, hourly, or minute-by-minute basis. +- g) Industrial production: Production of high-carbon industrial products (such as cement, steel), or industrial production indices. +- h) Residential consumption: Natural gas consumption data for residential living, regularly compiled and published by natural gas supply companies, usually on a daily or hourly basis. + +# 8 GHG emission data processing + +Due to the fact that urban GHG data usually comes from different sources, the collected raw data needs to be further cleaned, organized, and standardized in order to establish a unified data set for subsequent analysis. Specifically, this includes: + +- a) Data cleaning: Data cleaning is the first step in data processing, which mainly involves selecting, deduplicating, filling missing values, and handling outliers of the raw data to ensure accuracy and completeness of the data. + - i) Deduplication: Removing duplicate data to avoid double accounting. + - ii) Denoising: Removing noise or outliers from the data to reduce errors and improve data quality. Common methods for removing outliers include the z-score method, the $3\sigma$ (3-sigma) rule, and the boxplot method. + - The z-score method calculates the z-score for each data point and removes those that have a z-score greater than a certain threshold (typically 3 or 4). This method identifies outliers based on how far a data point deviates from the mean. + - The $3\sigma$ rule identifies outliers by considering the standard deviation of the data. According to this rule, data points that are more than 3 standard deviations away from the mean are considered outliers. + - The boxplot method uses the interquartile range (IQR) to identify outliers. It constructs a box around the middle 50% of the data and marks any data points that fall above or below a certain range as outliers. This method is particularly useful for detecting outliers in skewed datasets. + +- b) Interpolation: Filling missing data with interpolation methods for subsequent data fusion and analysis. Common methods including linear interpolation (estimating missing values by drawing a straight line between the closest known values on either side of the gap and assigning intermediate values) or spline interpolation (using mathematical functions, e.g., cubic splines, to estimate missing values based on the overall trend of the data). +- c) Normalization: Data normalization is the process of standardizing the data from different sources to ensure comparability of the data. + +By going through these steps, the accuracy, completeness, and comparability of the data can be ensured, providing a reliable foundation for subsequent integration of urban GHG data into a unified data set. + +# 9 GHG emission data fusion + +The method of fusing accurate regional emission data and high-resolution active data, including data alignment, data association, and data estimation, which is shown in Figure 3. + +- Data alignment: This involves aligning the regional emission data and the high-resolution active data to ensure that they can be properly merged. This is done by matching the data formats, units, and time periods of the two datasets. +- Data association: In order to accurately merge the two datasets, it is necessary to associate the high-resolution active data with the corresponding regions in the emission data. This is done by using geographic information system (GIS) data and other spatial analysis tools to match the location of the high-resolution active data with the corresponding regions in the emission data. +- Data interpolation: Once the two datasets are aligned and associated, data interpolation techniques are used to fill in any missing data or gaps in the datasets. This involves using statistical methods, such as regression analysis, to estimate missing data based on the available data and other relevant factors. + +![Figure 3: A simplified workflow of data processing and fusion. The diagram shows three main stages: Original data source, Processing module, and Emissions. The Original data source shows a screenshot of a 'Actual Generation per Production Type' table. The Processing module shows a screenshot of a code editor with Python code. The Emissions stage shows a line graph of CO2 emissions over time. Below these, a detailed workflow is shown in two columns: Pre-processing (in Python) and Fusion and calculation (in Python). Pre-processing includes Deduplication (df.drop_duplicates()), Denoising (df[(df>=Q1-1.5*IQR)&(df<=Q3+1.5*IQR)]), and Interpolation (df.interpolate(method='linear')). Fusion and calculation include Fusion (e.g., aggregating hourly data into daily: df.resample('D')) and Calculation (AD * EF, where AD is activity data and EF is emission factor). Line chart showing emission trends](410562339ce067fdc6fa41940c118658_img.jpg) + +**Original data source** + +Actual Generation per Production Type + +| Area | Actual Generation (TWh) | Fixed Emission Factor (tCO2/MWh) | Fixed CO2 Emission (tCO2) | +|-----------------------|-------------------------|----------------------------------|---------------------------| +| Asia | ... | ... | ... | +| Asia (excl. China) | ... | ... | ... | +| Asia (excl. India) | ... | ... | ... | +| Asia (excl. Japan) | ... | ... | ... | +| Asia (excl. Korea) | ... | ... | ... | +| Asia (excl. Taiwan) | ... | ... | ... | +| Asia (excl. Thailand) | ... | ... | ... | +| Asia (excl. Vietnam) | ... | ... | ... | + +**Processing module** + +``` + +# Python code snippet +import pandas as pd +... +df.drop_duplicates() +... + +``` + +**Emissions** + +Jan, 1st - Jun, 30th 2020 / Jan, 1st - Jun, 30th 2019 +-98.48 Mt CO2 (-19.32 %) + + + +Pre-processing (in Python) + +| | | +|---------------|--------------------------------------------------------------| +| Deduplication | df.drop_duplicates() | +| Denoising | df[(df>=Q1-1.5*IQR)&(df<=Q3+1.5*IQR)] | +| Interpolation | df.interpolate(method = 'linear') | + +Fusion and calculation (in Python) + +| | | +|-------------|-------------------------------------------------------------------------| +| Fusion | E.g., aggregating hourly data into daily: df.resample('D') | +| Calculation | $AD * EF$
(AD = activity data; EF = emission factor) | + +L.1640(24) + +Figure 3: A simplified workflow of data processing and fusion. The diagram shows three main stages: Original data source, Processing module, and Emissions. The Original data source shows a screenshot of a 'Actual Generation per Production Type' table. The Processing module shows a screenshot of a code editor with Python code. The Emissions stage shows a line graph of CO2 emissions over time. Below these, a detailed workflow is shown in two columns: Pre-processing (in Python) and Fusion and calculation (in Python). Pre-processing includes Deduplication (df.drop\_duplicates()), Denoising (df[(df>=Q1-1.5\*IQR)&(df<=Q3+1.5\*IQR)]), and Interpolation (df.interpolate(method='linear')). Fusion and calculation include Fusion (e.g., aggregating hourly data into daily: df.resample('D')) and Calculation (AD \* EF, where AD is activity data and EF is emission factor). Line chart showing emission trends + +Figure 3 – A simplified workflow of data processing and fusion + +# **10 GHG emission calculation** + +- a) Data collection and processing: The collection of GHG emission data in cities can be achieved through various technical means, such as using sensors, traffic flow monitoring, satellite remote sensing, etc. The collected data needs to be cleaned and processed for subsequent computation and analysis. +- b) GHG emission calculation model: To achieve near-real-time GHG emission calculation, an appropriate model needs to be established. The model should consider the characteristics and actual situation of the city, including traffic conditions, industrial and energy consumption, etc., to more accurately estimate GHG emissions: + - i) ICT goods, networks and services GHG emission should be accounted according to [ITU-T L.1410]. + - ii) ICT technology in organization GHG emission should be accounted according to [ITU-T L.1420]. + - ii) ICT GHG and energy project emission should be accounted according to [ITU-T L.1430] + - iv) ICT at city level GHG emission should be accounted according to [ITU-T L.1440]. + - v) ICT sector GHG emission should be accounted according to [ITU-T L.1450]. +- c) Support of cloud computing platform: GHG emission calculation requires a large amount of computing resources, so a cloud computing platform can be used to achieve this. Cloud computing platforms can provide high-performance computing, large-scale data processing and storage functions, thus achieving high efficiency and low cost of GHG emission calculation. +- d) Visualization and analysis: Data analysis can analyse and explain the monitoring results of GHG emissions in cities from multiple perspectives, thus better understanding the situation of GHG emissions in cities. Data analysis can use various methods, such as statistical analysis, visualization analysis, machine learning analysis, etc. The results of visualization analysis can be presented to users intuitively through charts, maps, reports, etc., thus better supporting city management and decision-making. The example of visualization analysis of GHG emissions for city is shown in Appendix II. + +# **11 Attribution analysis of GHG emission data and optimization strategy for sustainable development of city** + +## **11.1 Emission sources analysis and attribution analysis** + +Statistical analysis and machine learning methods achieve the recognition and classification of GHG emissions sources. Classification of the emissions sources, meaning the assigning of the properties for the studied GHG emissions to one of the sources. Recognition of the emissions sources, meaning the establishing of the affiliation for GHG emissions to one of the disjoint known sources. + +Quantitative attribution analysis can serve as a proxy for similar events occurring at different temporal and spatial scales, which should consist of the following components: + +- To assess the emission levels using historical activity levels as benchmarks and identify the hotspots of emission increases. +- To explore the decoupling relationship between activity levels and carbon emissions. +- To investigate influencing factors and facility-based contributions using multiplicative decomposition analysis and the related attribution analysis. + +## **11.2 Optimization strategy for sustainable development of city** + +An optimization strategy should be designed and implemented to reduce emissions. The technology optimization methods consist of the following components: + +- Clean power promotion, including reduction of end-use fossil fuel through fuel substitution and electrification, renewable energy promotion, building zero-carbon electric power systems. +- Energy efficiency improvement through structural adjustment, product substitution, process re-engineering, energy saving and behavioural change from the consumer. +- Carbon negative technologies. +- Non-CO2 greenhouse gas emissions reduction technologies. + +The optimization strategy should be reviewed periodically to reflect changes in the mitigation strategy, challenges, and achievements. In the case of recertification, previous GHG emissions reduction work strategies should be reviewed to examine whether previous goals and objectives have been met. + +## Appendix I + +### Example of monitoring city-level CO2 emissions from ground transportation in China + +(This appendix does not form an integral part of this Recommendation.) + +### I.1 General procedure of the example + +This example discusses in the case of a lack of high-frequency fuel consumption statistics in urban transportation, how to establish a congestion index-traffic flow model by using only road traffic flow data during certain periods in the city, combined with the near-real-time congestion index of the city's road network. Based on simulated near-real-time traffic flow data, the fuel consumption and greenhouse gas emissions of the transportation department are estimated (Figure I.1). In this example, we established a road traffic emission model for Beijing, and the road traffic flow data during certain periods comes from real research and statistics on roads, while the road congestion index of the entire road network comes from digital map vendors. We will apply the model constructed in this example to 100 cities in China to estimate the near-real-time changes in traffic greenhouse gas emissions in these cities. + +![Flowchart for estimating real-time traffic carbon emissions in cities. The process is divided into two main stages: 'Data collection' and 'Data preprocess and fusion'. 'Data collection' includes three boxes: 'Daily traffic volume in Beijing (From December 2021 to March 2022)', 'Daily traffic congestion index in 100 cities (Daily update)', and 'Annual CO2 emissions from ground transportation in 100 cities'. Arrows from the first two boxes point to a 'Regression' box in the 'Data preprocess and fusion' stage. The 'Regression' box points to 'Daily traffic volume in 100 cities', which in turn points to 'Estimating real-time emissions'. The third box from 'Data collection' also points directly to 'Estimating real-time emissions'. A label 'L.1640(24)' is at the bottom right.](a83ba9e3e2c1e21dd69953a7b09e45b4_img.jpg) + +``` + +graph LR + subgraph DC [Data collection] + DC1[Daily traffic volume in Beijing +(From December 2021 to March 2022)] + DC2[Daily traffic congestion index in 100 cities +(Daily update)] + DC3[Annual CO2 emissions from ground +transportation in 100 cities] + end + subgraph DPF [Data preprocess and fusion] + R[Regression] + DV[Daily traffic volume in 100 cities] + E[Estimating real-time emissions] + end + DC1 --> R + DC2 --> R + R --> DV + DV --> E + DC3 --> E + L164024[L.1640(24)] + +``` + +Flowchart for estimating real-time traffic carbon emissions in cities. The process is divided into two main stages: 'Data collection' and 'Data preprocess and fusion'. 'Data collection' includes three boxes: 'Daily traffic volume in Beijing (From December 2021 to March 2022)', 'Daily traffic congestion index in 100 cities (Daily update)', and 'Annual CO2 emissions from ground transportation in 100 cities'. Arrows from the first two boxes point to a 'Regression' box in the 'Data preprocess and fusion' stage. The 'Regression' box points to 'Daily traffic volume in 100 cities', which in turn points to 'Estimating real-time emissions'. The third box from 'Data collection' also points directly to 'Estimating real-time emissions'. A label 'L.1640(24)' is at the bottom right. + +**Figure I.1 – Flowchart for estimating real-time traffic carbon emissions in cities** + +### I.2 Example of collecting city-level activity data + +Table I.1 shows the types of raw data collected for estimating city-level ground transportation CO2 emissions in China. + +**Table I.1 – Raw data used for estimating near-real-time daily city-level ground transportation CO2 emissions in China** + +| Data | Description | +|----------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Daily traffic flow | Daily traffic flow for all roads in Beijing from December 26, 2021 to March 29, 2022 | +| Daily traffic congestion index | The index is updated daily and covers 100 cities nationwide, as it represents the ratio of the actual trip time to the trip time in uncongested conditions. | +| Annual CO 2 emissions | Total ground transportation CO 2 emissions in 100 cities nationwide for the year 2019 | + +### I.3 Example for data process and data fusion + +This section aimed to estimate near-real-time daily emissions from ground transportation by utilizing the daily traffic congestion index as a proxy for the daily on-road car flux. To this end, the primary objective of this section was to establish the relationship between the daily traffic congestion index and the daily traffic flow to complete the daily traffic flow data for 100 cities. The daily traffic congestion index represented the ratio of the actual trip time to the trip time in uncongested conditions. A daily traffic congestion index with a value of 1 did not necessarily indicate zero emissions but rather indicated that traffic flow was fluid or 'normal'. To estimate the lower threshold of emissions, daily traffic flow data for all roads in Beijing from December 26, 2021, to March 29, 2022, was utilized, and the same was defined as the mean number of passing vehicles recorded by the camera within one hour. + +A sigmoid function with regression parameters $\alpha$ , $\beta$ , $\gamma$ , and $\lambda$ was utilized to represent the relationship between the daily traffic congestion index $X$ and the daily traffic flow $Q$ , as shown in Equation (I.1) [b-Da]: + +$$Q = \alpha + \frac{\beta[100(X-1)]^\gamma}{\lambda^\gamma + [100(X-1)]^\gamma} \quad (I.1)$$ + +The model was fitted using the least squares method, and the fitting results were presented in Table I.2. The flow model was found to be close to the real traffic flow in Beijing. Although traffic characteristics vary among cities, it was assumed that daily traffic flow for other cities follows a similar relationship to the fitting models in Beijing (Equation I.1), and this model was applied to the other 99 cities. While the use of city-specific regression models would improve accuracy, it is believed that this approach is a reasonable approximation of Beijing's traffic condition and is known to be a good representation of the country's average due to its high diversity in road types. + +**Table I.2 – Regression parameters of the sigmoid function of Equation I.1 that describe the relationship between traffic flow ( $Q$ ) and congestion and delays indicators ( $X$ )** + +| Regression parameter | Value | +|----------------------|----------| +| $\alpha$ | 11089.30 | +| $\beta$ | 23460.82 | +| $\lambda$ | 1.40 | +| $\gamma$ | 17.93 | + +### I.4 Example for estimating daily GHG emissions in near-real-time + +Assuming a linear relationship between daily CO2 emissions and daily traffic flow, the daily CO2 emissions from ground transportation are established based on annual CO2 emissions and daily traffic flow as the distribution coefficient. Equation (I.2) shows the daily ground transportation emissions $E_{c,d}$ for a specific city $c$ in day $d$ : [b-Da], [b-Zhu 1]. + +$$E_{c,d} = Q_{c,d} \times \frac{E_{c,y}}{\sum_d Q_{c,d}} \quad (I.2)$$ + +where $E_{c,d}$ is the ground transportation emissions for city $c$ in day $d$ , $E_{c,y}$ is the ground transportation emissions for city $c$ in year $y$ , and $Q_{c,d}$ is traffic flow for city $c$ in day $d$ . + +Equation (I.3) establishes the daily CO2 emission model of ground transportation for the 100 cities in China, with daily ground transportation emissions $E_{c,d}$ in day $d$ given by Equation (I.3) [b-Da], [b-Zhu 1]: + +$$E_{c,d} = Q_{c,d} \times \frac{E_{c,2019}}{\sum_d Q_{c,d}} \quad (I.3)$$ + +where $E_{c,d}$ is the ground transportation emissions for city $c$ in day $d$ , $E_{c,2019}$ is the ground transportation emissions for city $c$ in 2019, and $Q_{c,d}$ is traffic flow for city $c$ in day $d$ . + +## Appendix II + +### Alibaba Cloud's "Carbon Vision" platform showing city near-real-time GHG emissions (mocked data) + +This appendix presents an example of visualization analysis of GHG emissions for city, including the functions of monitoring energy consumption, energy intensity as well as GHG emission from different locations of the city. Additionally, it can also show GHG emission trends and the energy resources composition of the city. + +![Alibaba Cloud Carbon Vision platform dashboard showing various charts and data for carbon emission simulation.](1c427123350e0e73e2a109b79069314b_img.jpg) + +The figure is a screenshot of the Alibaba Cloud Carbon Vision platform, titled "Carbon Emission Simulation Platform". It displays various data visualizations and metrics for carbon emissions and energy consumption. + +**Top Summary Metrics:** + +- Energy Consumption (Mton per year): 23.07 +- Carbon Emissions (Mton per year): 60 +- Energy Intensity (kge per yuan): 0.03 +- Carbon Emission Intensity (kg per yuan): 0.07 + +**Carbon Emission for Region (Line Chart):** Shows predicted and actual emissions from 2010 to 2060. The y-axis is in Mton, with a value of 10400 shown for 2020. + +**Monthly trend of electricity (Stacked Area Chart):** Shows electricity consumption trends by sector (Total, Predicted, Energy, Traffic, Industry, Agriculture, Resident) from January to November. The y-axis is in Mwh. + +**Industrial Carbon Emission (Table):** + +| Name | Area | Carbon Emission | +|------------------------|----------|-----------------| +| xxx Cement Company | Lanzhou | 1,897 Mton | +| xxx Flat Glass Company | Longkou | 1,097 Mton | +| xxx Paper Mill | Mouping | 960 Mton | +| xxx Food Factory | Changdao | 903 Mton | +| xxx Company | Zhifu | 2,090 Mton | + +**Energy Structure (Donut Chart):** Shows the percentage distribution of energy sources: Coal, Oil, Gas, Thermal Power, Solar Power, Wind power, Nuclear Power, and Hydropower. The chart is labeled with values 10, 16, 25, and 24. + +**Industrial Carbon Emission (Stacked Bar Chart):** Shows the percentage distribution of primary, secondary, and tertiary industries, plus resident waste treatment, for the years 2019, 2020, and 2021. + +**Regional Carbon Emissions (Bar Chart):** Shows carbon emissions by sector in units of 10k tons. + +| Sector | Value (10k tons) | +|---------------|------------------| +| Power | 816 | +| Steel | 722 | +| Cement | 689 | +| Metallurgy | 652 | +| Petrochemical | 571 | +| Chemical | 512 | +| Traffic | 341 | +| Aviation | 321 | + +**Map:** A map of the region showing various cities and their associated carbon emission values: Changdao (480), Penglai (1000), Zhifu (1000), Fushan (530), Mouping (600), Laishan (1200), Xiaxia (1600), Laiyang (550), Haiyang (1800), Longkou (1350), and Zhaoyuan (1400). Lanzhou is also marked with a value of 1000. + +Note that the data are mocked. + +Alibaba Cloud Carbon Vision platform dashboard showing various charts and data for carbon emission simulation. + +## Bibliography + +- [b-Da] Da Huo, Kai Liu, Jianwu Liu, Yingjian Huang, Taochun Sun, Yun Sun, Caomingzhe Si, Jinjie Liu, Xiaoting Huang, Jian Qiu, Haijin Wang, Duo Cui, Biqing Zhu, Zhu Deng, Piyu Ke, Yuli Shan, Olivier Boucher, Grégoire Dannet, Gaoqi Liang, Junhua Zhao, Lei Chen, Qian Zhang, Philippe Ciais, Wenwen Zhou & Zhu Liu (2022). *Near-real-time daily estimates of fossil fuel CO2 emissions from major high-emission cities in China. Scientific Data.* **9**, 684. +- [b-Zhu 1] Zhu Liu, Taochun Sun, Ying Yu, Piyu Ke, Zhu Deng, Chenxi Lu, Da Huo, Xiang Ding (2022). *Near-Real-Time Carbon Emission Accounting Technology Toward Carbon Neutrality. Engineering.* **14**, 44-51. +- [b-Zhu 2] Zhu Liu, Philippe Ciais, Zhu Deng, Steven J. Davis, Bo Zheng, Yilong Wang, Duo Cui, Biqing Zhu, Xinyu Dou, Piyu Ke, Taochun Sun, Rui Guo, Haiwang Zhong, Olivier Boucher, François-Marie Bréon, Chenxi Lu, Runtao Guo, Jinjun Xue, Eulalie Boucher, Katsumasa Tanaka & Frédéric Chevallier (2020). *Carbon Monitor, a near-real-time daily dataset of global CO2 emission from fossil fuel and cement production. Scientific Data.* **7**, 392. + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1700-201606-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg b/marked/L/T-REC-L.1700-201606-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..827609df9ad8667ae079f875841506349f063390 --- /dev/null +++ b/marked/L/T-REC-L.1700-201606-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:c0d2afb537db9f3588854962a991eb1178220b2bbb8ff3cea6712979a53a864b +size 4107 diff --git a/marked/L/T-REC-L.1700-201606-I_PDF-E/c0e88e4bd3a209b66ee7cb67e1cec2be_img.jpg b/marked/L/T-REC-L.1700-201606-I_PDF-E/c0e88e4bd3a209b66ee7cb67e1cec2be_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..59fe37af5e1e5bcd0ffd9138e0a323d0253da731 --- /dev/null +++ b/marked/L/T-REC-L.1700-201606-I_PDF-E/c0e88e4bd3a209b66ee7cb67e1cec2be_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:5cd8f533e25b3e92ecb9dc0604acc1f06513ca0e6c994f1f77ead3095d18a266 +size 46103 diff --git a/marked/L/T-REC-L.18-200805-I_PDF-E/2150ae7f14a2e4ad1866ac0c8ec685ad_img.jpg b/marked/L/T-REC-L.18-200805-I_PDF-E/2150ae7f14a2e4ad1866ac0c8ec685ad_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..2384cf1bd35c13120cea9c9c55af72de2c785e31 --- /dev/null +++ b/marked/L/T-REC-L.18-200805-I_PDF-E/2150ae7f14a2e4ad1866ac0c8ec685ad_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:34a1567b636a1a5b7402b206511c3afa62edacd9a022e5c6c24c3e9ff942bb5c +size 25188 diff --git a/marked/L/T-REC-L.18-200805-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg b/marked/L/T-REC-L.18-200805-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..d5a35041124e73f88d6638cd17f42a2eb4f6781a --- /dev/null +++ b/marked/L/T-REC-L.18-200805-I_PDF-E/a3dc41dc3df86ea68d266af2bf95cf5b_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:8f24b214263bab4142643453a604fb5196f9397e2500c675cde79d53ce5e5d8e +size 3645 diff --git a/marked/L/T-REC-L.18-200805-I_PDF-E/raw.md b/marked/L/T-REC-L.18-200805-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..183059e69cbc45c1e43eae7c9e80ceeca14a15a2 --- /dev/null +++ b/marked/L/T-REC-L.18-200805-I_PDF-E/raw.md @@ -0,0 +1,433 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.18** + +(05/2008) + +SERIES L: CONSTRUCTION, INSTALLATION AND +PROTECTION OF CABLES AND OTHER ELEMENTS OF +OUTSIDE PLANT + +# --- **Sheath closures for terrestrial copper telecommunication cables** + +Recommendation ITU-T L.18 + + + +## **Recommendation ITU-T L.18** + +# **Sheath closures for terrestrial copper telecommunication cables** + +## **Summary** + +Recommendation ITU-T L.18 deals with the design, mechanical and environmental characteristics of cable sheath closures for copper cables, applied in telecommunication networks in duct, tunnel, buried, surface troughing and aerial installations. + +## **Source** + +Recommendation ITU-T L.18 was approved on 29 May 2008 by ITU-T Study Group 6 (2005-2008) under Recommendation ITU-T A.8 procedure. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2009 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +# CONTENTS + +| | Page | +|-------------------------------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Characteristics of closures for copper cable ..... | 1 | +| 3.1 Design of the closure ..... | 1 | +| 3.2 Mechanical characteristics..... | 3 | +| 3.3 Environmental characteristics ..... | 3 | +| Appendix I – Environmental classification..... | 5 | +| I.1 Basic environmental classes ..... | 5 | +| I.2 Special conditions..... | 6 | +| Appendix II – Typical performance requirements for sealed non-pressurized copper closures ..... | 7 | +| Appendix III – Typical performance requirements for sealed pressurized copper closures.... | 10 | +| Bibliography..... | 13 | + +# Introduction + +A copper cable telecommunication network will require, at certain locations, cable interconnections (cable joints) because: + +- a) cables are not necessarily continuous from one terminal point to the other +- b) cables may need to be branched +- c) cables may have been damaged. + +A cable joint consists of spliced conductors and a closure. The methods for splicing conductors are covered in a separate Recommendation ITU-T L.9: *Methods of terminating metallic cable conductors* and further information is also found in the ITU-T Handbook, *Outside plant technologies for public networks* (Part II, Chapter 3 – Symmetrical and coaxial pairs jointing techniques). + +Basically, a closure is a structure, which is attached at the outer surface of the ends of the sheaths of the cables to be jointed, covering the spliced conductors and thereby restoring the integrity of the cable sheaths at the cable joint. The closure should: + +- Protect the spliced conductors from the environment in the type of plant where it is installed, directly buried, in ducts and tunnels, in surface troughing and as an aerial installation (wall, pole and pole line). +- Provide mechanical strength across the sheath opening between the cable ends. +- Provide electrical bonding and grounding of the metal parts of the sheath where required. The method of achieving this will vary with the type of cable sheath. Further information is given in Recommendations ITU-T K.11 and K.25 and the ITU-T manual: *Protection of telecommunication lines against lightning discharges*. + +## Recommendation ITU-T L.18 + +## Sheath closures for terrestrial copper telecommunication cables + +# 1 Scope + +This Recommendation: + +- Deals with the design of cable sheath closures for copper cables used in telecommunication networks, for all types of outside plant environments. +- Deals with the mechanical and environmental characteristics of sheath closures for copper cable. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[IEC 60068.x] IEC 60068.x-series, *Environmental testing*. + +# 3 Characteristics of closures for copper cable + +Closure design and the required characteristics may be differentiated depending on a number of parameters as listed below. The type of network for which the closure is designed (pressurized, underground, etc.), as well as any limitation in its application domain (for example, compatibility with branch configurations) should be clearly indicated to the user. Clear and correct installation instructions should be made available, indicating which tools are required, the necessary safety regulations and precautions to be taken and how to select the correct closure size. + +## 3.1 Design of the closure + +### 3.1.1 Installation environment and sealing level + +The closure should be mechanically suitable with respect to its application and the environment in which it is to be placed. + +To prevent corrosion or other electro/chemical damage, the materials should be compatible with other materials normally used in outside plant. + +The level of sealing (water-tightness) must be in accordance with the application environment and pressure in the network. + +#### 3.1.1.1 Underground closures + +Closures for underground networks (for example, ducted, direct buried) should be resistant to permanent water immersion. + +Closures for use in pressurized plant should be able to withstand the operating pressure without leaking during their expected lifetime. Air valves are required to reduce the pressure for safe re-entry or as a feeding point to increase the pressure and may be required on the closure for measurement purposes. + +#### **3.1.1.2 Aerial closures** + +For aerial networks, different levels of sealing are applied, depending on the network and local practices. + +For a sealed network, the closure should not allow air exchange with the environment, and in general it would be suitable for accidental submersion. + +For free-breathing networks, the closure design should prevent water penetrating the actual splice due to rain, wind or water running along the cable. Openings should be provided to evacuate water or condensation from the closure. The size of these openings should be limited in order to prevent entry of harmful insects. + +### **3.1.2 Direction by which the cables enter the closure** + +Closure designs can also be differentiated by the direction through which the cables enter the closure: + +- butt closures: all cables enter and leave the closure at one end +- in-line closures: cables enter or leave the closure via two opposite ends +- Y or T-shaped closures: main cables enter the closure via opposite ends (cfr in-line) while one or more (branch) cables leave the closure under an angle (Y) or perpendicular (T) to the main axis of the closure. + +### **3.1.3 Cable characteristics & configuration** + +The materials of the closure should be compatible with the materials of the cable sheath. + +Special provisions may be required in order to cope with cables having various sheath combinations. + +The closure should not affect the specified electrical characteristics of the cable or the spliced conductors. + +The closure should be able to cope with the required cable sizes and cable configurations entering the closure, as agreed between customer and supplier. + +### **3.1.4 Wrap-around installability** + +Designs may allow for installation around a continuous cable without having to cut all of the conductors, for example, when connecting a customer drop cable within a cable length. This feature is also referred to as "wrap-around" closures. Tubular closure designs do not provide this feature, requiring all conductors to be cut and re-spliced in order to be able to add a branch cable. + +### **3.1.5 Filling compounds** + +Some closures rely on the application of a filling compound to protect the splice from water penetration. Filling compounds can be greases, gels or reactive 2-component systems. The filling compound may be already present from the factory or added upon installation. + +### **3.1.6 Installation method** + +Closure designs employ cold or hot installation processes based upon the sealing method used. + +Cold installed closures make use of mastics, tapes, grommets, O-rings, rubber shapes, pastes, gels, potting compounds, adhesives, etc., which do not require heat. Cold installed closures include mechanical closures which can be reused. + +Hot installed closures include the use of thermo-shrinkable materials, lead plumbing and polyethylene injection welding. The heat source may be a gas flame, a hot air generator or electrical resistance heating. + +Closures should be installable at temperatures between $-10^{\circ}\text{C}$ and $+45^{\circ}\text{C}$ , unless agreed otherwise between customer and supplier. + +### **3.1.7 Re-entrability and addition of cables** + +For certain applications, it may be necessary to reopen closures and even add additional cables. In that case, reopening of the closure should be possible without interruptions to the working circuits. + +## **3.2 Mechanical characteristics** + +The mechanical characteristics should be considered according to the conditions of the installation. Where appropriate, test methods according to [IEC 60068.x] should be used for mechanical tests. + +### **3.2.1 Bending** + +After installation, the closure may be subjected to bending stresses due to dynamic conditions encountered by the cables and shifts in the earth in directly buried applications. The closures should maintain a seal to the cable sheaths and should not permit cable movement which could transfer strain to the conductors. + +### **3.2.2 Axial tension** + +Dynamic conditions, especially in aerial and duct plant and shifts in the soil in directly buried applications, may cause cyclic and static tensile loads in the cable. These tensile loads should be supported by the closure without affecting the seal to the sheaths and transferring strain to the conductors. + +### **3.2.3 Crush and impact** + +The closure may be subjected to crush (also called "static load") and impact both just after installation and during operational life at different temperatures. The closure should protect the spliced conductors under normal crush and/or impact loading experienced during the life of the cable system. In certain circumstances, for directly buried closures, additional protection may be provided, for instance, by placing the closure within a suitable housing. + +### **3.2.4 Torsion** + +Under dynamic conditions during operation, the cable may be subjected to torsion. The closure should be able to transmit the torque across the joint without cable slippage while maintaining the seal to the cable sheaths. + +### **3.2.5 Vibration** + +Cable joints may be located on messenger strands, underground in manholes, on bridges and other structures or directly buried. As a result of their location, they may be subjected to vibrations from wind, traffic, railways, etc. The closure should be able to withstand these vibrations without loss of function. + +## **3.3 Environmental characteristics** + +The environmental characteristics should be considered according to the conditions of the location of the closure. Wherever appropriate, test methods according to [IEC 60068.x] should be used for environmental tests. + +### **3.3.1 Temperature variations** + +During their operational life, cable joints may experience severe temperature variations. The closure should be able to withstand the temperature variations without loss of function. + +Operating temperature range should be in accordance with the application environment. An example of environmental classification with typical operating temperatures can be found in Appendix I. + +### **3.3.2 Water penetration** + +The closure should prevent the entry of water. + +### **3.3.3 Moisture permeation** + +During their operational life, cable joints may be immersed in water or exposed to high humidity. High humidity levels in the joint are not desirable because of corrosion and possible condensation with changes in temperature. Therefore, it is important to take the humidity of the environment into account when selecting the type of closure and the materials used in the joint. + +A desiccant may be installed in the closure to control the humidity in the closure during its lifetime. Based upon the moisture characteristics of the closure, the quantity of desiccant can be defined in order not to exceed a given level of relative humidity. Various materials, such as a metal screen, will reduce the moisture permeation rate. + +### **3.3.4 Electrical continuity of metal sheaths** + +The metal sheath (if present) of the cables terminating into a cable joint will usually have to be electrically interconnected with one another at the joint. This can be done for measurement purposes, for safety considerations or for minimizing the possible effects of lightning. + +When the cable may be subjected to induced voltage from electrified railways, insulation of the metallic sheath at the joint is sometimes prescribed. + +### **3.3.5 Grounding** + +Provisions for grounding may be required at the closure (for example, for areas with frequent or severe lightning (high keraunic level) or in the vicinity of power lines), in accordance with local practices or regulations. + +### **3.3.6 UV (solar) radiation** + +Cable joints may be subjected to UV radiation from sunlight when installed in aerial plant or other sun exposed locations. All closures, intended for use in this type of environments, should be UV resistant. + +### **3.3.7 Snow and ice** + +In some aerial and duct applications, the closure will be exposed to and be coated with snow and/or ice. The performance of the closure should not be degraded by the presence of snow or ice. + +### **3.3.8 Fluid resistance** + +The closure should resist the fluids that it might normally be exposed to during its lifetime. + +### **3.3.9 Fire resistance** + +In tunnels and other internal installations, closures may be required to be manufactured from material having defined flammability and smoke emission properties. + +# Appendix I + +## Environmental classification + +(This appendix does not form an integral part of this Recommendation) + +For passive copper joints, a set of five basic different environmental classes covers the majority of the applications around the globe. This appendix describes these environmental classes in some more detail. + +## **I.1 Basic environmental classes** + +### **IC: Indoor temperature controlled** + +- inside buildings protected by a roof and walls all around, heating or air-conditioning available +- contact with chemical and biological contaminants is negligible, e.g., inside central offices, some remote network buildings/houses, residential buildings. + +### **IN: Indoor non-temperature controlled** + +- inside buildings protected by a roof and walls all around, no heating or air-conditioning available +- contact with chemical and biological contaminants is negligible, e.g., cable vaults, basements, remote network buildings/houses, inside garages, warehouses. + +### **OA: Outdoor above ground** + +- all outdoor non-sheltered locations, above ground level +- no other sources of heat or extreme temperatures than the surrounding air or solar radiation +- exposed to contaminants and dust that may occur in the atmosphere in rural, city or industrial areas +- e.g., wall mounted, pole mounted, strand mounted nodes. + +### **OG: Outdoor ground level** + +- outdoor, standing on the ground, perhaps with a base that resides partially below the ground; this class may also apply to outdoor wall mounted products which are close to ground level +- exposed to contaminants and dust that may occur in the atmosphere in rural, city or industrial areas; the base of the product may be permanently in contact with soil, biological and chemical contaminants that occur at or just below ground or street-level, e.g., along roads, pavements and railroads. + +### **OS: Outdoor underground (Sub Terrain)** + +- outdoor below ground level +- exposed to soil or water-borne contaminants, including organic and inorganic agents related to the presence of roads and traffic, e.g., in man-holes, hand-holes or direct buried. + +## I.2 Special conditions + +### Extreme + +- any environment for which at least one of the environmental parameters exceeds the boundaries of the five basic environmental classes as specified above, e.g., more extreme temperature excursions +- exact test settings are to be agreed between the supplier and the customer. + +### Additional requirements + +- In specific cases, extra constraints may be required on top of the conditions of one of the basic environmental classes (e.g., bullet resistance, accidental flooding, etc.). This is not included under the term "extreme" conditions: For these occasions, additional requirements or tests can be added on top of the test program of the basic environmental class; +- see also Appendix III for information on potential additional requirements. + +**Table I.1 – Summary of typical parameters for the basic environmental classes** + +| | Indoor | | Outdoor | | | +|-------------------------------|--------------------------------------------------------------------------------------------------|---------------------|------------------------------------------------------------------------------|--------------------------------|-----------------| +| | IC | IN | OA | OG | OS | +| Exposure ↓ | Temp controlled | Temp non controlled | Above ground | Ground level | Underground | +| Temp Min (°C) | +5 | –10 | –40 | –40 | –30 | +| Temp Max (°C) | +40 | +60 | +65 | +65 | +60 | +| Solar Radiation | No | | Yes | Yes | No | +| Relative Humidity (max) (%) | 93%
(decreasing once above 30°C) | | 100%
(occasional/permanent exposure to water possible) | | | +| Precipitation | No | | Rain, Snow,... | Rain, Snow,... | N.A. | +| Submersion | No b) | | No | No b) | Yes | +| Vibration (m/s 2 ) | 10-55 Hz
1 m/s 2 (~0.1g) (whole system)
5 m/s 2 (~0.5g) (components) | | 5-500 Hz
10 m/s 2 (~1g)
(due to, e.g., traffic, wind, etc.) | | | +| Chemical | Negligible a) | | Atmospheric | Atmospheric + Soil (base only) | Soil/waterborne | +| Biological | Negligible | | Atmospheric | Atmospheric + Soil (base only) | Soil/waterborne | + +a) In areas where corrosive atmospheres can be expected (marine and coastal areas, industrial areas, urban pollution), increased corrosion protection may be requested as an additional requirement. + +b) If accidental flooding may occur, e.g., in vaults or basements, this is to be added as a conditional requirement. This will also correspond to a higher IP rating according to [b-IEC 60529]. + +# Appendix II + +## Typical performance requirements for sealed non-pressurized copper closures + +(This appendix does not form an integral part of this Recommendation) + +| Performance criteria | Method and conditions | | Intern. Norm/ref | Requirements | +|----------------------------------------|----------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------|------------------------------------------------------------| +| Performance criteria references | | | | | +| Appearance | Examination with the unaided naked eye | | | No defects which will adversely affect product performance | +| Tightness1) | Test temperature:
Internal pressure:
Test time: | $(23 \pm 3)^\circ\text{C}$
$(40 \pm 2)$ kPa
15 min | [IEC 60068-2-17]
Test Qc | No continuous emission of air bubbles | +| Installation tests | | | | | +| Closure installability | Assembly between: | $(-10 \text{ and } 45) \pm 2^\circ\text{C}$ | | Tightness
Prior to subsequent product testing | +| Mechanical tests | | | | | +| Axial tension2) | Test temp. range:
Test pressure:
Load: 3)

Test time: | $(-5 \text{ to } +45) \pm 2^\circ\text{C}$
$(40 \pm 2)$ kPa regulated
$D/45 \times 1000$ N, max. 1000 N
or
$D/45 \times 500$ N, max. 500 N
8 hrs each cable | | Tightness | +| Bending2) | Test temp. range:

Test pressure:
Bend:
Force:
Clamp at:
Duration: | $(-5 \text{ to } +45) \pm 2^\circ\text{C}$
$(40 \pm 2)$ kPa regulated
$30^\circ$ or max. 300 mm displacement
max. 500 N
$10 \times D$ (min. 250 mm)
2 cycles/cable | | Tightness | +| Impact2) | Test temp. range:
Test pressure:
Impact tool:
Weight:
Drop height:
Site of impact:
No. of impacts: | $(-5 \pm 2)^\circ\text{C}$
$(40 \pm 2)$ kPa regulated
Steel ball
$(1000 \pm 10)$ g
2 m
in the centre
1 | | Tightness | +| Static load2) | Test temp. range:
Test pressure:
Time:
Load:
Area:
No. of applications: | $(-5 \text{ to } +45) \pm 2^\circ\text{C}$
$(40 \pm 2)$ kPa regulated
5 min
$(1000 \pm 10)$ N
$25 \text{ cm}^2 \pm 10\%$
2 | | Tightness | + +| Performance criteria | Method and conditions | | Intern. Norm/ref | Requirements | +|------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------|-----------------------------|----------------------------------| +| Torsion2) | Test temp. range:
Test pressure:
Torque:
Clamp at:
Duration:
No. of cycles: | (-5 to +45) ± 2°C
(40 ± 2) kPa regulated
Max. 50 Nm or 90° rotation
10 × D (min. 250 mm)
5 min
2 cycles/cable | | Tightness | +| Vibration | Test temp. range:
Test pressure:
Vibration:
Amplitude:
Clamping distance:
Test time: | (+10 to +45) ± 2°C
(40 ± 2) kPa regulated
10 Hz, sinusoidal
3 mm (6 mm peak-to-peak)
10 × D (min. 250 mm)
10 days | [IEC 60068-2-6]
Test Fc | Tightness | +| Environmental tests | | | | | +| Resistance to aggressive Media A | Test temperature:
Test pressure:
Test media:
Test time: | (23 ± 3)°C
(40 ± 2) kPa regulated
pH 2, pH 12
30 days | | Tightness | +| Resistance to aggressive Media B4) | Test temperature:
Test pressure:
Test media:

Test time: | (23 ± 3)°C
(40 ± 2) kPa regulated
Diesel for cars
Petroleum jelly
7 days | EN 590 | Tightness | +| Resistance to residual stress cracking | Test temperature:
Test pressure:
Test medium:
Test time: | (50 ± 2)°C
(40 ± 2) kPa regulated
10% Igepal
7 days | | Tightness
No visible cracking | +| Temperature cycling | High temperature:
Low temperature:
Dwell/Transition time:
Cycle duration:
Internal pressure:
No. of cycles: | (60 ± 2)°C
(-30 ± 2)°C
4 hrs/2 hrs
12 hrs
(40 ± 2) kPa regulated
10 | [IEC 60068-2-14]
Test Nb | Tightness | +| Salt fog | Test temperature:
Spray solution:
Test time: | (35 ± 2)°C
5% NaCl
30 days | [IEC 60068-2-11]
Test Ka | No visible degradation | + +| Performance criteria | Method and conditions | | Intern. Norm/ref | Requirements | +|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------|------------------------------|-----------------------------|------------------| +| Waterhead5) | Test temperature:
Depth:
Test time: | (23 ± 3)°C
5 m
30 days | [IEC 60068-2-17]
Test Qf | No water ingress | +| 1) For closures that are complete filled (e.g., grease, rubber gel, reactive filling compound), testing with internal pressure is not appropriate. For this style of closures, tightness can be checked by visual check or resistance measurement during water immersion.
2) Low end test temperature should be at least –5°C, but may be lower upon agreement between supplier and customer. For some tests, minimum test temperature may also be limited by the properties of the cables used.
3) D = Diameter of the cable in mm; Required axial tension level to be agreed between customer and supplier.
4) Aggressive media B are not required for products that will only be used above ground.
5) Waterhead test is not mandatory for aerial closures. | | | | | + +# Appendix III + +## Typical performance requirements for sealed pressurized copper closures + +(This appendix does not form an integral part of this Recommendation) + +| Performance criteria | Method and conditions | | Intern. Norm/ref | Requirements | +|-------------------------------------------------|----------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------|------------------------------------------------------------| +| Performance criteria references | | | | | +| Appearance | Examination with the unaided naked eye | | | No defects which will adversely affect product performance | +| Tightness1) | Test temperature:
Internal pressure:
Test time: | $(23 \pm 3)^\circ\text{C}$
$(100 \pm 2)$ kPa
15 min | [IEC 60068-2-17]
Test Qc | No continuous emission of air bubbles | +| Installation tests | | | | | +| Closure installability | Assembly between: | $(-10 \text{ and } 45) \pm 2^\circ\text{C}$ | | Tightness
Prior to subsequent product testing | +| Mechanical tests | | | | | +| Axial tension2) | Test temp. range:
Test pressure:
Load: 3)

Test time: | $(-5 \text{ to } +45) \pm 2^\circ\text{C}$
$(70 \pm 2)$ kPa regulated
$D/45 \times 500$ N, max. 500 N
or
$D/45 \times 1000$ N, max. 1000 N
8 hrs each cable | | Tightness | +| Bending/
Ladder test2) 5) | Test temp. range:
Test pressure:
Bend:

Force:
Clamp at:
Duration:

Duration:

Load: | $(-5 \text{ to } +45) \pm 2^\circ\text{C}$
$(70 \pm 2)$ kPa regulated
Cables < 50 mm: Bend test
$\pm 30^\circ$ or max. 300 mm displacement
max. 500 N
$10 \times D$ (min. 250 mm)
Hold 5 min per position
2 cycles/cable
Cables > 50 mm: Ladder test
$1 \times 2$ hrs per (group of) cables(s)
800 N | | Tightness | +| Impact2) | Test temp. range:
Test pressure:
Impact tool:
Weight:
Drop height:
Site of impact:
No. of impacts: | $(-5 \pm 2)^\circ\text{C}$
$(70 \pm 2)$ kPa regulated
Steel ball
$(1000 \pm 10)$ g
2 m
in the centre
1 | | Tightness | + +| Performance criteria | Method and conditions | | Intern. Norm/ref | Requirements | +|------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------|-----------------------------|----------------------------------| +| Static load2) | Test temp. range:
Test pressure:
Time:
Load:
Area:
No. of applications | (-5 to +45) ± 2°C
(70 ± 2) kPa regulated
5 min
(1000 ± 10) N
25 cm 2 ± 10%
2 | | Tightness | +| Torsion2) | Test temp. range:
Test pressure:
Torque:
Clamp at:
Duration:
No. of cycles: | (-5 to +45) ± 2°C
(70 ± 2) kPa regulated
Max. 50 Nm or 90° rotation
10 × D (min. 250 mm)
5 min
2 cycles/cable | | Tightness | +| Vibration | Test temp. range:
Test pressure:
Vibration:
Amplitude:
Clamping distance:
Test time: | (+10 to +45) ± 2°C
(70 ± 2) kPa regulated
10 Hz, sinusoidal
3 mm (6 mm peak-to-peak)
10 × D (min. 250 mm)
10 days | [IEC 60068-2-6]
Test Fc | Tightness | +| Environmental tests | | | | | +| Resistance to aggressive Media A | Test temperature:
Test pressure:
Test media:
Test time: | (23 ± 3)°C
(70 ± 2) kPa regulated
pH 2, pH 12
30 days | | Tightness | +| Resistance to aggressive Media B4) | Test temperature:
Test pressure:
Test media:
Test time: | (23 ± 3)°C
(70 ± 2) kPa regulated
Diesel for cars
Petroleum jelly
7 days | EN 590 | Tightness | +| Resistance to residual stress cracking | Test temperature:
Test pressure:
Test medium:
Test time: | (50 ± 2) °C
(70 ± 2) kPa regulated
10% Igepal
7 days | | Tightness
No visible cracking | +| Temperature cycling | High temperature:
Low temperature:
Dwell/Transition time:
Cycle duration:
Internal pressure:
No. of cycles: | (60 ± 2)°C
(-30 ± 2)°C
4 hrs/2 hrs
12 hours
(70 ± 2) kPa regulated
10 | [IEC 60068-2-14]
Test Nb | Tightness | +| Salt fog | Test temperature:
Spray solution:
Test time: | (35 ± 2)°C
5% NaCl
30 days | [IEC 60068-2-11]
Test Ka | No visible degradation | + +| Performance criteria | Method and conditions | | Intern. Norm/ref | Requirements | +|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------|----------------------------------------------|-----------------------------|------------------| +| Waterhead6) | Test temperature:
Depth:
Test time: | $(23 \pm 3)^\circ\text{C}$
5 m
30 days | [IEC 60068-2-17]
Test Qf | No water ingress | +| 1) For closures that are complete filled (e.g., grease, rubber gel, reactive filling compound), testing with internal pressure is not appropriate. For this style of closures, tightness can be checked by visual check or resistance measurement during water immersion.
2) Low end test temperature should be at least $-5^\circ\text{C}$ , but may be lower upon agreement between supplier and customer. For some tests, minimum test temperature may also be limited by the properties of the cables used.
3) D = Diameter of the cable in mm; Required axial tension level to be agreed between customer and supplier.
4) Aggressive media B are not required for products that will only be used above ground.
5) For cables $> 50$ mm Outer diameter, traditional bending test is not representative for real life situations. For these cable sizes, the ladder test, simulating the load of an installer, stepping on a product that is supported by its cables is recommended.
6) Waterhead test is not mandatory for aerial closures. | | | | | + +![Diagram of the 'Ladder test' for cables with diameter > 50 mm. The diagram shows a cable (labeled 'sample') held horizontally by two 'cable clamp' units. The distance between the clamps is labeled 'clamping distance 10 x D'. A load, represented by a red hatched rectangle labeled '800 N', is applied vertically to the cable between the clamps. The load is labeled 'load' with an arrow pointing to it.](2150ae7f14a2e4ad1866ac0c8ec685ad_img.jpg) + +Diagram of the 'Ladder test' for cables with diameter > 50 mm. The diagram shows a cable (labeled 'sample') held horizontally by two 'cable clamp' units. The distance between the clamps is labeled 'clamping distance 10 x D'. A load, represented by a red hatched rectangle labeled '800 N', is applied vertically to the cable between the clamps. The load is labeled 'load' with an arrow pointing to it. + +**Figure III.1 – "Ladder test" for cables with diameter $> 50$ mm** + +# Bibliography + +- [b-ITU-T K.11] Recommendation ITU-T K.11 (1993), *Principles of protection against overvoltages and overcurrents.* +- [b-ITU-T K.25] Recommendation ITU-T K.25 (2000), *Protection of optical fibre cables.* +- [b-ITU-T L.9] Recommendation ITU-T L.9 (1988), *Methods of terminating metallic cable conductors.* +- [b-ITU-T Handbook] ITU-T Handbook (1992), *Outside Plant Technologies for Public Networks.* (It describes in detail various closure systems in use in the telecommunications network (see Part II, Chapter 4 – Methods of jointing cable sheaths).) +- [b-ITU-T manual] ITU-T manual (1995), *The Protection of Telecommunication Lines and Equipment against Lightning Discharges.* +- [b-IEC 60529] IEC 60529 (2001), *Degrees of protection provided by enclosures (IP Code).* <> + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.1801-202602-I_PDF-E/4801720824e4b5e2361a5564f91cfb70_img.jpg b/marked/L/T-REC-L.1801-202602-I_PDF-E/4801720824e4b5e2361a5564f91cfb70_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..2b401d8ce83c249878e188c503237c5f68fcc66e --- /dev/null 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@@ +version https://git-lfs.github.com/spec/v1 +oid sha256:df7827160e606cbd83f6e01c1f913e209aa8ced8bc36fa4c75e529fe310bdad1 +size 47157 diff --git a/marked/L/T-REC-L.208-201908-I_PDF-E/raw.md b/marked/L/T-REC-L.208-201908-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..1a6818ead0357a09e761f5c9f670495d72e5022e --- /dev/null +++ b/marked/L/T-REC-L.208-201908-I_PDF-E/raw.md @@ -0,0 +1,893 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.208** + +(08/2019) + +SERIES L: ENVIRONMENT AND ICTS, CLIMATE +CHANGE, E-WASTE, ENERGY EFFICIENCY; +CONSTRUCTION, INSTALLATION AND PROTECTION +OF CABLES AND OTHER ELEMENTS OF OUTSIDE +PLANT + +Optical infrastructures – Infrastructure including node +elements (except cables) + +# --- **Requirements for passive optical nodes– Fibre distribution box** + +Recommendation ITU-T L.208 + +## ITU-T L-SERIES RECOMMENDATIONS + +## ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT + +| | | +|---------------------------------------------------------------|--------------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node elements (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +## Recommendation ITU-T L.208 + +# Requirements for passive optical nodes – Fibre distribution box + +## Summary + +Recommendation ITU-T L.208 refers to a fibre distribution box (FDB) deployed as a passive optical node in indoor or outdoor environments. It details the FDB housing, FDB fibre management system, cable attachment and termination system, and specifies the mechanical and environmental characteristics. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.208 | 2019-08-29 | 15 | 11.1002/1000/14030 | + +## Keywords + +Enclosures, fibre distribution boxes, interconnection, outside plant, passive optical nodes. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2019 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|------|--------------------------------------------------------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 3 | +| 3.1 | Terms defined elsewhere ..... | 3 | +| 3.2 | Terms defined in this Recommendation..... | 3 | +| 4 | Abbreviations and acronyms ..... | 3 | +| 5 | Conventions ..... | 3 | +| 6 | Characteristics of fibre distribution boxes..... | 3 | +| 6.1 | General requirements..... | 3 | +| 6.2 | FDB housing..... | 4 | +| 6.3 | FDB fibre management system (organizer system) ..... | 5 | +| 6.4 | Cable attachment and termination system..... | 6 | +| 7 | Performance evaluation test program ..... | 6 | +| 8 | Sample preparation ..... | 7 | +| | Annex A – Performance evaluation criteria..... | 8 | +| A.1 | Sealing and visual evaluation ..... | 8 | +| A.2 | Optical evaluation..... | 8 | +| | Annex B – Performance test program for indoor non-temperature controlled and outdoor above ground FDBs ..... | 10 | +| B.1 | Mechanical and sealing evaluation..... | 10 | +| B.2 | Optical evaluation..... | 12 | +| | Appendix I – Product characterization checklist ..... | 14 | +| | Appendix II – Indian experience..... | 17 | +| II.1 | Introduction ..... | 17 | +| II.2 | Different types of FTDB ..... | 17 | +| II.3 | Attributes of FTDB..... | 20 | +| | Bibliography..... | 22 | + +# Introduction + +Fibre distribution boxes (FDBs) are widely used for protection of interconnection points between multi-fibre distribution cables and drop cables in access networks. The boxes along with internal functional assemblies can be referred to as fibre distribution boxes. An FDB comprises a mechanical structure (FDB housing) for mechanical protection and environmental sealing of internal systems, an FDB fibre management system for guiding, storing and managing the fibres and fibre connections inside the node, and a cable attachment and termination system for attaching and terminating cable ends of multi-fibre distribution cables and drop cables. A fibre distribution box will: + +- work as a fibre distribution area near the users in access network; +- protect the fibres, fibre interconnections and optical devices from indoor environment or outdoor environment at above ground level, usually mounted on wall or pole; +- provide for the organization of the fibre interconnections, passive devices and the storage of fibre overlength (excess fibre length); +- provide electrical bonding and grounding of the metal parts of the cable sheath and strength members. + +# Requirements for passive optical nodes – Fibre distribution box + +# 1 Scope + +This Recommendation provides the requirements of a fibre distribution box (FDB) and the means for characterization and evaluation of the performance of an FDB according to the principles of [ITU-T L.200]. This includes mechanical performance, sealing performance and optical stability of the product which simulate the effect of environmental factors or interventions related to network maintenance and reconfiguration. It contains a basic test program for the box which is globally applicable. Additional requirements may be agreed upon between customer and supplier to reflect local or special conditions. All functions and features that a product may contain should be reflected in the mix of test samples that are subjected to the test program. + +This Recommendation: + +- refers to an FDB as a passive optical node in an access network; +- details the characteristics and requirements of the housing, the FDB fibre management system and the cable attachment and termination system; +- specifies mechanical and environmental characteristics of the FDB; +- specifies characteristics of the FDB fibre management system; +- provides a test plan for the performance evaluation of FDB used in indoor non-temperature controlled (IN) or outdoor above ground (OA) (See [ITU-T L.200]); +- discusses the simulation of the effect of interventions related to network maintenance and reconfigurations; +- provides a checklist for a systematic product characterization according to [ITU-T L.200]. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T G.652] Recommendation ITU-T G.652 (2016), *Characteristics of a single-mode optical fibre and cable*. +- [ITU-T G.657] Recommendation ITU-T G.657 (2016), *Characteristics of a bending-loss insensitive single-mode optical fibre and cable*. +- [ITU-T K.11] Recommendation ITU-T K.11 (2009), *Principles of protection against overvoltages and overcurrents*. +- [ITU-T K.47] Recommendation ITU-T K.47 (2012), *Protection of telecommunication lines against direct lightning flashes*. +- [ITU-T L.200] Recommendation ITU-T L.200/L.51 (2003), *Passive node elements for fibre optic networks – General principles and definitions for characterization and performance evaluation*. + +- [ITU-T L.361] Recommendation ITU-T L.361/L.64 (2012), *ID tag requirements for infrastructure and network elements management*. +- [IEC 60529] IEC 60529 (2013), *Degrees of protection provided by enclosures (IP Code)*. +- [IEC 60950-1] IEC 60950-1 (2013), *Information technology equipment – Safety – Part 1: General requirements*. +- [IEC 61300-2-1] IEC 61300-2-1 (2009), *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-1: Tests – Vibration (sinusoidal)*. +- [IEC 61300-2-4] IEC 61300-2-4 (2019), *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-4: Tests – Fibre or cable retention*. +- [IEC 61300-2-5] IEC 61300-2-5 (2009), *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-5: Tests – Torsion*. +- [IEC 61300-2-9] IEC 61300-2-9 (2017), *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-9: Tests – Shock*. +- [IEC 61300-2-12] IEC 61300-2-12 (2009), *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-12: Tests – Impact*. +- [IEC 61300-2-22] IEC 61300-2-22 (2007), *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-22: Tests – Change of temperature*. +- [IEC 61300-2-26] IEC 61300-2-26 (2006), *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-26: Tests – Salt mist*. +- [IEC 61300-2-33] IEC 61300-2-33 (2012), *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-33: Tests – Assembly and disassembly of fibre optic mechanical splices, fibre management systems and closures*. +- [IEC 61300-2-34] IEC 61300-2-34 (2009), *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-34: Tests – Resistance to solvents and contaminating fluids of interconnecting components and closures*. +- [IEC 61300-2-37] IEC 61300-2-37 (2016), *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-37: Tests – Cable bending for fibre optic closures*. +- [IEC 61300-3-1] IEC 61300-3-1 (2005), *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 3-1: Examinations and measurements – Visual examination*. +- [IEC 61300-3-3] IEC 61300-3-3 (2009), *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 3-3: Examinations and measurements – Active monitoring of changes in attenuation and return loss*. +- [IEC 61300-3-28] IEC 61300-3-28 (2012), *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 3-28: Examinations and measurements – Transient loss*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +None. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 FDB fibre management system (organizer system):** The whole of means and features that guide, protect and store fibres, connectors and passive optical components inside the fibre distribution box (FDB), at any location where they are not protected by the cable sheath. In an FDB, the optical fibres are properly managed and guided from where cables enter the node until their exit. + +**3.2.2 fibre distribution box:** A protective housing with an integrated fibre management system to protect the interconnection points between multi-fibre distribution cables and drop cables in an access network. + +**3.2.3 protective housing:** Protective housing refers to the outer shell of a fibre distribution box (FDB), not including the fibre management system or the cable attachment and termination system. Its main functions are protection and sealing of its contents. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|----------------------------------------| +| FDB | Fibre Distribution Box | +| FDH | Fibre Distribution Hub | +| FTDB | Fibre Termination and Distribution Box | +| IN | Indoor non-temperature controlled | +| IP | Ingress Protection | +| MDUB | Multi Dwelling Unit Box | +| ME | Multiple Element (mass storage) | +| OA | Outdoor Above ground | +| SC | Single Circuit | +| SE | Single Element | +| SF | Single Fibre | +| SR | Single Ribbon | +| WDM | Wavelength-Division Multiplexing | + +# 5 Conventions + +None. + +# 6 Characteristics of fibre distribution boxes + +## 6.1 General requirements + +Each FDB should comply with the general requirements as listed in clause 8 of [ITU-T L.200]. + +## 6.2 FDB housing + +The following should be considered: + +- dimensional compatibility to internal contents and installation site should be considered. A box is considered to be small, low weight and easy to be installed by one person without the need of special lifting equipment; +- the FDB housing should be re-openable for installation, maintenance or reconfiguration. Access to the product can be achieved by removing a cover or hinging a door. Hinging doors or covers should have a sufficient opening angle to allow reconfigurations, additions or replacements of fibre management system parts or modules. Typically, an angle of 110 degrees is considered sufficient; +- after being installed (with possible secondary protections), the FDB's housing protection level should comply with the requirements of ingress protection (IP) 30 or higher degrees in [IEC 60529] for IN applications, or comply with the requirements of IP 54 or higher degrees for OA applications; +- the FDB housing can be made from metal, engineering plastic, sheet moulding compound (SMC), sheet-form glass-fibre reinforced polyester material processed by compression moulding) or other suitable materials; +- the metallic parts of the FDB housing should be electrically bonded and grounded; +- the housing should allow access of cable ends of one or more multi-fibre distribution cables. If the fibres of drop cables are to be terminated inside the housing, the housing should also allow access of the drop cables. In cases where pre-terminated drop cables are used, the housing should allow the entry of connectors through the drop cable entry ports. If the fibres of the drop cables are terminated outside the housing, the housing should allow for installations of adapters and hardened connectors (water and dust tight connectors) on the housing. The apertures between cables or adaptors and the housing should allow sealing by proper materials to ensure the sealing performance. If used with mid-span applications, the housing should allow entry and storage of the uncut loose tubes; +- depending on installation styles, the housing allows the mounting on walls or poles. Accessories may be required for installations, and a same housing can be installed in various styles by changing accessories; +- if the housing is limited for use in certain applications and environments in the network, any limitations should be clearly indicated to the user. The detailed characterization of features and compatibility of an FDB can be done using the checklist in Appendix I; +- the housing should be made of materials which comply to local safety regulations. For OA applications, all polymeric materials that are exposed to the environment should be sufficiently resistant to fungi; materials that will be exposed to solar radiation should be UV resistant; metallic parts should be corrosion resistant when exposed to the salt mist test; +- if requested by a customer, the housing has provisions for secure lock and key to restrict access to authorized personnel; +- if requested by a customer, a theft proof mounting system has to be provided; +- if requested by a customer, multiple compartments with separate and restricted access have to be provided. This type of FDB can be used in cases that multiple operators share the subscriber drop cables. The separated compartments should be independently lockable and easy to identify. + +## 6.3 FDB fibre management system (organizer system) + +The FDB fibre management system is an integral part of the FDB. The system comprises: + +- one or more sheets or trays that have means for routing and holding fibre interconnections, fibre overlength, pigtails or drop cables in an orderly manner, and should minimize fibre strain and control fibre bend radius; +- interconnection interface between fibres of distribution cables and fibres of drop cables. It can be patch panels, splitters or wavelength-division multiplexing (WDM) components with adaptors inside the housing, or adaptors located on the housing; +- structures that have means for holding possible passive components, such as splitters, and WDM components. + +Compatibility and features of FDB fibre management system can be listed by using the checklist in Appendix I. The desired optical stability type can be selected according to [ITU-T L.200]. + +### 6.3.1 Characteristics of the FDB fibre management system + +The functions of the FDB fibre management system are: + +- to provide means for routing, storing and protecting fibres, fibre interconnections, uncut loose tubes or other passive devices in a predetermined order; +- to provide means for installation and reconfiguration of fibre circuits; +- to separate circuits up to a certain degree as defined in [ITU-T L.200]. This will limit the risk of interruption of traffic to those fibres that belong to the same group of circuits (see [ITU-T L.200]: single fibre (SF), single circuit (SC), single ribbon (SR), single element (SE), multiple element (ME)). For an FDB, separation degree higher than SE is preferred; +- to provide means for storing the fibre overlength required for jointing and for possible re-jointing in the future; +- to ensure that the fibre bend radius should not be less than 30 mm in general applications with [ITU-T G.652] fibres. A minimum bend radius of 20 mm can be agreed upon between customer and supplier (in order to maintain mechanical reliability and minimize losses in the network, the cumulative length of fibre, exposed to this smaller bend radius should be limited to less than 2 m per fibre link). In case of [ITU-T G.657] fibres, smaller bend radius is allowed (see [b-ITU-T G-Sup.59] for guidance on optical fibre and cable reliability); +- to provide an identification method for the location of the connections and stored fibre interconnections, allowing correct access to these connectors and stored fibre interconnections during maintenance and reconfiguration. A sort of labels on optical connectors (including optical adapters and plugs, etc.) can be useful to provide easy identification. The use of QR codes or electronic IDs is optional and should comply with the requirements of [ITU-T L.361]. + +The materials used for making the management system should be compatible with the other materials in the FDB and the degreasing agents as recommended in the installation instructions. + +### 6.3.2 Configurations of FDB fibre management system + +The trays or sheets of FDB fibre management system may be configured in several ways: + +- lateral sliding from a frame – similar to removing a book from a shelf; +- rotation about a hinge – similar to turning a page in a book; +- lifting from a stack – similar to lifting a book from a stack; or +- other possible configurations. + +All movements of the FDB fibre management system should proceed in a predetermined way in order to avoid uncontrolled movements or bends in the fibres which can cause optical losses or interruption of traffic during and after manipulations. + +If required by local regulations, the FDB fibre management system could be divided into multiple subsystems and stored in separate compartments in the housing so that multiple telecommunication operators can share the subscriber drop cables. + +## **6.4 Cable attachment and termination system** + +The following characteristics of cable attachment and termination system should be considered: + +- the system should allow for attachment of cable ends of multi-fibre distribution cables. If the fibres of drop cables are to be terminated inside the housing, the system should also allow for attachment of the drop cables. Normally, the parts for attachment of the distribution cables and the parts for attachment of the drop cables are separated and have various design; +- the system should allow for good bonding and grounding for metallic elements of cables, while the cable metallic elements should be insulated to other metallic parts of the box. The method of achieving electrical continuity will vary with the type of cable sheath and the type and location of the strength members. Further information is given in [ITU-T K.11], [ITU-T K.47] and [IEC 60950-1]; +- the system should be installed near the cable entry points in the FDB, normally the lower section of the box inner housing; +- the system should allow the addition or removal of cables without interruption to service on other cables; +- the materials used in the system should be compatible with the other materials in the FDB and the degreasing agents recommended in the installation instructions. + +# **7 Performance evaluation test program** + +The complete test program for an FDB consists of: + +- a basic test program for the applicable environment (see Annexes A and B); +- a number of additional requirements according to local standards when necessary (see [ITU-T L.200] and the checklist in Appendix I). + +For specific products, alternative test conditions to those given in Annex B may be agreed between customer and supplier. + +Tests should be executed according to [IEC 61300-2] test methods where available. + +The performance test program of an FDB should: + +- evaluate the product for two groups of criteria: mechanical and sealing evaluation and optical stability (see annex A); +- simulate the effects of exposure to: + - the environment in which it will be installed; + - an intervention at the node. +- simulate installation or maintenance conditions; +- evaluate all available features of the product. + +When an FDB is suitable for both environments IN and OA, it should pass the most severe conditions of either environment. As an alternative, the tests that are different for each of these environments may be duplicated at both settings. + +Two types of optical stability can be selected (see clause 6.2.1 of [ITU-T L.200]). For products that may be subject to an intervention on a live network, dynamic optical stability is recommended. + +# **8 Sample preparation** + +A representative number of test samples is to be prepared, taking into account the following parameters: + +- all product features and compatibility (see checklist in Appendix I); +- applicable sizes of cables; +- sealing performance test samples should be installed at: + - $-5\text{ }^{\circ}\text{C}$ , room temperature or $+45\text{ }^{\circ}\text{C}$ for OA applications; + - room temperature for IN applications; +- optical performance test samples should be installed at room temperature for OA and IN; +- for mechanical evaluation, a fresh sample should be prepared for each different test; if a failure occurs when consecutive testing is applied on the same sample, the failed test may be repeated on a fresh sample. + +Appendix I of [ITU-T L.200] illustrates how optical test samples can be prepared. Due to their complexity, consecutive testing on the same sample is most practical. + +## Annex A + +### Performance evaluation criteria + +(This annex forms an integral part of this Recommendation.) + +### A.1 Sealing and visual evaluation + +The performance evaluation criteria should be assured during or after tests in Annex B. + +#### A.1.1 Sealing performance + +International standard: [IEC 60529] + +Conditions: Conditions according to protection degree of the box: + +IP 30 or higher for IN; + +IP 54 or higher for OA + +Requirement: Meet the requirements of the protection degree of the box: + +IP 30 or higher for IN; + +IP 54 or higher for OA + +#### A.1.2 Visual examination + +International standard: [IEC 61300-3-1] + +Conditions: Examination of product with the unaided naked eye. + +Requirement: No defects and physical damages that would affect product performance. + +### A.2 Optical evaluation + +NOTE 1 – All optical losses indicated are referenced to the initial optical signal at the start of the test. + +NOTE 2 – An "incoming fibre" is defined as a part of an optical circuit containing the fibre entering the product, spliced to a fibre leaving the product. One optical circuit can contain many "incoming fibres". Light will sequentially flow through all the "incoming fibres". + +NOTE 3 – Fibre type used for single mode: [ITU-T G.652] D fibre. The applications with other fibre types (for example, [ITU-T G.657] fibre) will be qualified by similarity since most fibre types are equal or less sensitive to bending compared to the [ITU-T G.652] D fibre fibres. + +#### A.2.1 Change in insertion loss (attenuation) (static optical stability) + +International standard: [IEC 61300-3-3] Method 1 + +Conditions: Source wavelength: 1310, 1550 and 1625 nm. + +Requirement: **If only splices are part of the optical path:** + +$\Delta IL \leq 0.2$ dB (1310/1550 nm) per incoming fibre during the test +(excursion loss); + +$\Delta IL \leq 0.5$ dB (1625 nm) per incoming fibre during the test +(excursion loss); + +$\Delta IL \leq 0.1$ dB (1310/1550/1625 nm) per incoming fibre after the test +(residual loss). + +##### **If optical connectors are part of the optical path:** + +$\Delta IL \leq 0.2$ dB (1310/1550 nm) per incoming fibre during the test (excursion loss); + +$\Delta IL \leq 0.5$ dB (1625 nm) per incoming fibre during the test (excursion loss); + +$\Delta IL \leq 0.2$ dB (1310/1550/1625 nm) per incoming fibre after the test (residual loss). + +If other passive optical components are part of the optical path, the above-mentioned change in attenuation values should be increased with the maximum allowed change in attenuation value specified for this passive optical component. For wavelength selective components the test wavelength might have to be changed to the operating wavelength(s) of the component(s). + +#### **A.2.2 Transient loss (dynamic optical stability)** + +International standard: [IEC 61300-3-28] + +Conditions: Source wavelength: 1310, 1550 and 1625 nm. Measurements at 1550 nm and 1625 nm are particularly important for dynamic transient loss. 1310 nm is optional, subject to agreement between customer and supplier), unpolarized; detector bandwidth: (0-1500) Hz. + +Requirement: **If only splices are part of the optical path:** + +$\Delta IL \leq 0.5$ dB (1310/1550 nm) during the test measured in the life circuit (transient loss); + +$\Delta IL \leq 1.0$ dB (1625 nm) during the test measured in the life circuit (transient loss); + +$\Delta IL \leq 0.1$ dB (1310/1550/1625 nm) after the test in the life circuit (residual loss). + +##### **If optical connectors are part of the optical path:** + +$\Delta IL \leq 0.5$ dB (1310/1550 nm) during the test measured in the life circuit (transient loss); + +$\Delta IL \leq 1.0$ dB (1625 nm) during the test measured in the life circuit (transient loss); + +$\Delta IL \leq 0.2$ dB (1310/1550/1625 nm) after the test in the life circuit (residual loss). + +If other passive optical components are part of the optical path, the above-mentioned loss values should be increased with the maximum allowed change in attenuation value specified after test for this passive optical component. For wavelength selective components the test wavelength might have to be changed to the operating wavelength(s) of the component(s). + +## Annex B + +## Performance test program for indoor non-temperature controlled and outdoor above ground FDBs + +(This annex forms an integral part of this Recommendation.) + +For tests in this annex, the test settings are applicable for both environments IN and OA unless specifically marked. All testing is at room temperature unless otherwise stated. When sealing performance evaluation for dust and water ingress is required, it can be performed after all related tests have been finished, instead of after each of the tests. The performance criteria of visual examination, sealing performance, static and dynamic optical evaluation are in accordance with Annex A, if not otherwise specified in this Annex. For optical evaluations in clause B.2, the requirements for static or dynamic optical stability is to be agreed upon between customer and supplier, and the appropriate optical performance criteria are to be selected accordingly. + +### B.1 Mechanical and sealing evaluation + +#### B.1.1 Cable retention force (IN and OA) + +International standard: [IEC 61300-2-4] + +Conditions: Install cables of appropriate type on the FDB; +Load: $D \times 10$ N (maximum 500 N) per cable for multi-fibre distribution cables, where $D$ is the cable outer diameter in millimetres; +25 N per cable for drop cables. +Test time: +1 hour per cable for multi-fibre distribution cables; +1 min per cable for drop cables. + +Performance criteria: Visual appearance + +#### B.1.2 Cable bending (IN and OA) + +International standard: [IEC 61300-2-37] + +Conditions: Bending angle $\pm 30^\circ$ or maximum bending force 500 N is reached; +Point of application: 400 mm from end of seal. For cables with a very rigid construction (e.g., slotted core cables, armoured cables), the clamping distance may need to be increased to 1000 mm; +Keep angle for 5 minutes at each extreme position; +Number of cycles: 5 per cable + +Performance criteria: Visual appearance + +#### B.1.3 Cable torsion (IN and OA) + +International standard: [IEC 61300-2-5] + +Conditions: Install cables of appropriate type on the FDB; +Torsion angle $\pm 90^\circ$ or maximum torque 50 Nm is reached; +Torque application: 400 mm from the cable entry of the FDB. For cables with a very rigid construction (e.g., slotted core cables, armoured cables), the clamping distance may need to be increased to 1000 mm; +Duration at extreme position: 5 minutes; +Number of cycles: 5 per cable + +Performance criteria: Visual appearance + +#### **B.1.4 Impact (IN and OA)** + +International standard: [IEC 61300-2-12] Method B + +Conditions: Impact tool: steel ball; +Weight: 1 kg; +Drop height: 0.2 m for IN; +1 m for OA; +Test temperatures: room temperature for IN; + $(-15 \pm 2)^\circ\text{C}$ and $(+45 \pm 2)^\circ\text{C}$ for OA; +Location: centre of the top, and centre of front; +Number of impacts: 1 per location per test temperature. + +Performance criteria: Sealing performance: visual examination, no evidence of cracks and deformations, surface protective layer (if there is) does not fall off, scratches in surface can be ignored. + +#### **B.1.5 Temperature cycling (IN and OA)** + +International standard: [IEC 61300-2-22] + +Conditions (see Note): Lowest/highest temperature: $(-10 \pm 2)^\circ\text{C}$ / $(+60 \pm 2)^\circ\text{C}$ for IN; + $(-40 \pm 2)^\circ\text{C}$ / $(+65 \pm 2)^\circ\text{C}$ for OA; +Humidity: uncontrolled; +Dwell time: 4 hours; +Transition: $1^\circ\text{C}/\text{minute}$ ; +Number of cycles: 5 cycles for IN; +12 cycles for OA + +Performance criteria: Sealing performance: visual appearance + +NOTE – Temperature ranges for temperature cycling are recommended for global usage. Adaptations to specific local conditions can be agreed between customer and supplier. Humidity could also be considered. + +#### **B.1.6 Re-entries (IN and OA)** + +International standard: [IEC 61300-2-33] + +Conditions: Open the box and gain access to fibres and splices at each re-entry; +Aging between each re-entry: at least one thermal cycle (see B.1.5); +Number of re-entries: 5. + +Performance criteria: Sealing performance: visual appearance + +#### **B.1.7 Salt mist (OA)** + +International standard: [IEC 61300-2-26] + +Conditions: Exposure to a salt mist of 5% NaCl in water; +Test temperature: $(+35 \pm 2)^\circ\text{C}$ ; +Duration: 5 days + +Performance criteria: Visual appearance: no evidence of corrosion + +The salt mist test can be selectively performed on components, parts and materials that are at potential risk of corrosion, instead of the whole FDB. + +#### **B.1.8 Resistance to aggressive media (OA, as needed)** + +International standard: [IEC 61300-2-34] + +Conditions: Exposure to: HCl at pH 2; +NaOH at pH 12; +Duration: 5 days + +Performance criteria: Visual appearance: no evidence of corrosion, swelling or cracks. + +The resistance to aggressive media test can be selectively performed on components, parts and materials that are at potential risk corrosion, instead of the whole FDB. + +### **B.2 Optical evaluation** + +Construction of optical samples is according to Appendix I of [ITU-T L.200]. + +#### **B.2.1 Intervention at a node (IN and OA)** + +International standard: [IEC 61300-2-33] + +Conditions: Execute all manipulations that will normally occur for this product during an intervention after initial installation. A List of typical manipulations can be found in Appendix II of [ITU-T L.200]. + +Performance criteria: Visual appearance; +Static: change in attenuation (residual loss); +Dynamic: transient loss + +#### **B.2.2 Vibration (IN and OA)** + +International standard: [IEC 61300-2-1] + +Conditions: Sweep range: (5-500) Hz sinusoidal at 1 octave/minute; +Crossover frequency: 9 Hz; +– amplitude below 9 Hz: 1.5 mm for IN; +3.5 mm for OA. +– acceleration above 9 Hz: 5 m/s2 (~0.5 g) for IN; +10 m/s2 (~1 g) for OA. +Direction: 3 mutually perpendicular axes; +Duration: 10 cycles (5-500-5 Hz)/axis + +Performance criteria: Visual appearance; +Static: change in attenuation (residual loss); +Dynamic: transient loss + +#### **B.2.3 Shock (IN and OA)** + +International standard: [IEC 61300-2-9] + +Conditions: Wave form: half sine; +Duration: 11 milliseconds; +Acceleration: 150 m/s2 (~15g); +Direction: 3 mutually perpendicular axes; +Number of shocks: 3 up and 3 down per axis + +Performance criteria: Visual appearance; +Static: change in attenuation (residual loss); +Dynamic: transient loss + +#### **B.2.4 Temperature cycling (IN and OA)** + +International standard: [IEC 61300-2-22] + +Conditions (See Note): Lowest/highest temperature: $(-10 \pm 2) ^\circ\text{C} / (+60 \pm 2) ^\circ\text{C}$ for IN; + $(-40 \pm 2) ^\circ\text{C} / (+65 \pm 2) ^\circ\text{C}$ for OA; + +Humidity: uncontrolled; + +Dwell time: 4 hours; + +Transition: $1 ^\circ\text{C}/\text{minute}$ ; + +Number of cycles: 5 cycles for IN; +12 cycles for OA + +Performance criteria: Visual appearance; +Static: change in attenuation (excursion and residual loss) + +NOTE – Temperature ranges for temperature cycling are recommended for global usage. Adaptations to specific local conditions can be agreed between customer and supplier. Humidity could also be considered. + +## Appendix I + +### Product characterization checklist + +(This appendix does not form an integral part of this Recommendation.) + +This checklist facilitates the systematic characterization of the features and capabilities of a fibre distribution box. It reflects the parameters that are described in [ITU-T L.200]. It may be useful for preparation of the products' test program as well as product description for tenders and purchasing specifications, comparison of different or competitive products and creation of commercial information and ordering guides. + +#### Product name: + +### Material of FDB housing + +- Metal +- SMC +- Other: ..... + +### Application environment(s) (see clause 7.1 of [ITU-T L.200]) + +- IN Indoor non-temperature controlled level +- OA Outdoor above ground level +- E Extreme (describe differences versus a basic environmental class) + +### IP protection class + +- IP 30 +- IP 54 +- Other: ..... + +### Optical functionality and compatibility (see clause 6 of [ITU-T L.200]) + +#### – *optical stability level:* + +- Static +- Dynamic (transient free) + +#### – *wavelength* (see clause 6.3 of [ITU-T L.200]) + +- 1310 nm +- 1550 nm +- 1625 nm +- Other: ..... + +#### – *cable construction* (see clause 6.1.1 of [ITU-T L.200]) + +- Loose buffer tube +- Micro-sheath +- Central core +- Slotted core +- Blown fibre +- Break out cable +- Interfacility cable +- Other: ..... + +– ***fibre type, fibre grouping, fibre coating*** (see clause 6.1.2 of [ITU-T L.200]) + +- Single mode + - Bend in-sensitive single mode fibre +- Ribbon 4 +- R8 +- R12 +- R24 +- Other: ..... +- Primary coated (~250 µm) +- Secondary coated (~900 µm) + +– ***passive devices*** (see clause 6.1.3 of [ITU-T L.200]): + +- Splice type: + - Fusion + - Mechanical (brand/type): ..... +- Splice protector type: + - Heatshrink (min/max dimensions): ..... + - Mechanical (brand/type): ..... +- Connectors: specify brand/type: ..... + - Branching devices: (describe type, split ratio etc.): ..... + - Delivered as preassembled/prefibred modules yes no + - Other passive devices: (describe) ..... + - Delivered as preassembled/prefibred modules yes no + +– ***fibre storage and separation level*** (see clause 6.2.2 of [ITU-T L.200]) + +| | Circuit separation level | | | | | +|-----------------------------------------------------|---------------------------------|--------------------------|--------------------------|--------------------------|--------------------------| +| | ME | SE | SR | SC | SF | +| Uncut fibre (looped fibre) | | | | | | +| Splices | | | | | | +| Passive optical components | | | | | | +| Other: ..... | | | | | | + +### Additional or special requirements and features + +- ***storage/transport conditions*** (see clause 7.2 of [ITU-T L.200]) + - Normal: public transport – indoor storage + - Special handling/transport: ..... + - Special storage: ..... +- ***additional (conditional) requirements*** (see Appendix III of [ITU-T L.200]): + - Bullet/shotgun proof according to: ..... + - Earthquake resistance according to: ..... + - Freeze-thaw resistance according to: ..... + - Fire-related performance according to: ..... + - Fire Retardancy according to: ..... + - Halogen free according to: ..... + - Low smoke emission according to: ..... + - Electrical grounding and shield continuity according to: ..... + - Current surge according to: ..... + - Insulation resistance according to: ..... + - Contact resistance according to: ..... + - Rodent resistance according to: ..... + - Termite resistance according to: ..... + - Steam resistance according to: ..... + - Cable blocking according to: ..... + - Other: ..... according to: ..... + +## Appendix II + +## Indian experience + +(This appendix does not form an integral part of this Recommendation.) + +## II.1 Introduction + +This appendix gives examples of typical fibre termination and distribution box (FTDB) to provide management of optical fibres, cables, and optical splitter assemblies for interconnection points between feeder and distribution cables or between distribution and drop cables in FTTx network. The FTDB provides facilities for reconfiguration of fibres, network expansion, testing and store extra length of fibres, un-cut loose tube, and pigtails and have provision for cable termination and sealing requirements. + +### II.2 Different types of FTDB + +Based on location of installation, number of fibres to be spliced and/or connected, following types of FTDB [b-TEC/GR/TX/FTB] are defined: + +#### – **Type-II: Multi dwelling unit box – Indoor (MDUB-I)** + +This type of wall mountable box is typically installed on a wall of a building to cater to a small cluster of subscribers and to connect drop and distribution cables. The fibres of incoming cables are distributed into outgoing cables either by direct splicing or by splicing with pigtail and patching with pre-polished connectors or by pre-connectorized cables. The box has the provision to hold splices and connector adapters. Suitable identification labelling is provided on the box. The box may have provision to accommodate secondary splitter (cassette or bare). + +### – **Type-III: Multi dwelling unit box – Outdoor (MDUB-O)** + +This type of wall or pole mountable box is typically installed outdoors to cater a small cluster of single residential units or small buildings and to connect drop and distribution cables. The fibres of incoming cables are distributed into outgoing cables either by direct splicing or by splicing with pigtail and patching with pre-polished connectors or by pre-connectorized cables. The box has the provision to hold splices and connector adapters. Suitable identification labelling is provided on the box. The box may have provision to accommodate secondary splitter (cassette or bare). + +### – **Type-IV: Fibre distribution hub – Indoor (FDH-I)** + +This type of wall mountable box is typically installed in the basement of a building to connect feeder and distribution cables through optical splitters in a FTTx network application. The box has the provision to hold splices, connector adapters and splitters. The entire internal assembly allows simultaneous access of all the elements depending on where they are terminated/connected. Suitable identification labelling is provided on the box. + +#### – **Type-V: Fibre distribution hub – Outdoor (FDH-O)** + +This type of wall or pole mountable box is typically installed in the outside plant (OSP) environment for connecting optical cables and splitters. The box is to facilitate fibre serving area that includes mid-rise buildings, single residential unit and MDU structures. The box has the provision to hold splices, connector adapters and splitters. The entire internal assembly allows simultaneous access of all the elements depending on where they are terminated/connected. Suitable identification labelling is provided on the box. + +Figure II.1 shows a typical example of distribution on a building floor. + +![Diagram of a typical fiber optic distribution on a building floor. An OLT (Optical Line Terminal) provides 12F IN to an FDH-I (TYPE-IV) unit. The FDH-I unit contains a Splitter that outputs 96F OUT. These 96F OUT fibers are split into two MDUB-I (TYPE-II) units, each receiving 24F. Each MDUB-I (TYPE-II) unit contains a Splitter that outputs 2F to multiple FLAT units (FLAT 1 to FLAT N). Each FLAT unit is connected to an SPB (TYPE-I) unit. The diagram is labeled L.208(19)_FII.1.](c5452f95f3b28f1bfe29e84fbc2e1267_img.jpg) + +``` + +graph LR + OLT[OLT] -- "12F IN" --> FDH1[FDH-I TYPE-IV] + subgraph FDH1 + S1[Splitter] + end + S1 -- "96F OUT" --> MDUB1[MDUB-I TYPE-II] + S1 -- "96F OUT" --> MDUB2[MDUB-I TYPE-II] + subgraph MDUB1 + S2[Splitter] + end + subgraph MDUB2 + S3[Splitter] + end + S2 -- "2F" --> FLAT1_1[FLAT 1] + S2 -- "2F" --> FLATN_1[FLAT N] + S3 -- "2F" --> FLAT1_2[FLAT 1] + S3 -- "2F" --> FLATN_2[FLAT N] + FLAT1_1 --> SPB1[SPB TYPE-I] + FLATN_1 --> SPBN_1[SPB TYPE-I] + FLAT1_2 --> SPB2[SPB TYPE-I] + FLATN_2 --> SPBN_2[SPB TYPE-I] + +``` + +Diagram of a typical fiber optic distribution on a building floor. An OLT (Optical Line Terminal) provides 12F IN to an FDH-I (TYPE-IV) unit. The FDH-I unit contains a Splitter that outputs 96F OUT. These 96F OUT fibers are split into two MDUB-I (TYPE-II) units, each receiving 24F. Each MDUB-I (TYPE-II) unit contains a Splitter that outputs 2F to multiple FLAT units (FLAT 1 to FLAT N). Each FLAT unit is connected to an SPB (TYPE-I) unit. The diagram is labeled L.208(19)\_FII.1. + +NOTE 1 – In the above diagram, MDUB-I (Type-II) shows 12 outgoing cables of 2F. It can be any combination of cables depending on the actual site requirements provided the total number of outgoing fibres does not exceed 24. + +NOTE 2 – The FDH-I (Type-IV) will house splitter modules. It will have 12 incoming fibres and up to 96 outgoing fibres. + +NOTE 3 – TYPE-I is subscriber premises box (SPB), which is out of scope of this Recommendation. + +**Figure II.1 – Typical example of distribution on a building floor** + +Figure II.2 shows a typical example of distribution on a single residential unit cluster. + +![Diagram of a typical example of distribution on a single residential unit cluster. An OLT connects to an FDH-O (TYPE-V) via 12F IN. The FDH-O has 96F OUT and connects to two MDUB-O (TYPE-III) units via 24F IN. Each MDUB-O (TYPE-III) connects to 12 SBP 2F (TYPE-I) units, represented by house icons numbered 1 through 12. Dashed lines indicate connections between SBP 2F (TYPE-I) units.](7133ccf78043568ca62ecbcd43628a4a_img.jpg) + +The diagram illustrates a fiber optic distribution network. On the left, an OLT (Optical Line Terminal) is connected to an FDH-O (TYPE-V) unit via a 12F IN cable. The FDH-O unit has a 96F OUT cable. This cable connects to two MDUB-O (TYPE-III) units via 24F IN cables. Each MDUB-O (TYPE-III) unit is connected to 12 SBP 2F (TYPE-I) units, represented by house icons numbered 1 through 12. Dashed lines indicate connections between SBP 2F (TYPE-I) units. The diagram is labeled L.208(19)\_FII.2. + +Diagram of a typical example of distribution on a single residential unit cluster. An OLT connects to an FDH-O (TYPE-V) via 12F IN. The FDH-O has 96F OUT and connects to two MDUB-O (TYPE-III) units via 24F IN. Each MDUB-O (TYPE-III) connects to 12 SBP 2F (TYPE-I) units, represented by house icons numbered 1 through 12. Dashed lines indicate connections between SBP 2F (TYPE-I) units. + +NOTE 1 – In the above diagram, MDUB-O (Type-III) shows 12 outgoing cables of 2F. It can be any combination of cables depending on the actual site requirements provided the total number of outgoing fibres does not exceed 24. + +NOTE 2 – The FDH-O (Type-V) will house splitter modules. It will have 12 incoming fibres and up to 96 outgoing fibres. + +NOTE 3 – TYPE-I is Subscriber Premises Box (SPB), which is out of scope of this document. + +**Figure II.2 – Typical example of distribution on a single residential unit cluster** + +Figure II.3 shows typical examples of FDBs used as FDH and MDUB for low fibre density applications. + +![Three photographs of fibre distribution boxes. The top photo shows an open box with labels: Box mounting hole, Hinged door, Gasket for intrusion protection, Adapters, and Box mounting hole. The middle photo shows an open box with labels: Splitter component holder, Lock, Splice holder area, Feeder/distribution cable, and Distribution/drop cable. The bottom photo shows an open box with a label: Splitter module. A small text 'L.208(19)_FII.3' is at the bottom right.](7b517f15a2d307945bd78e30c13a75bd_img.jpg) + +Three photographs of fibre distribution boxes. The top photo shows an open box with labels: Box mounting hole, Hinged door, Gasket for intrusion protection, Adapters, and Box mounting hole. The middle photo shows an open box with labels: Splitter component holder, Lock, Splice holder area, Feeder/distribution cable, and Distribution/drop cable. The bottom photo shows an open box with a label: Splitter module. A small text 'L.208(19)\_FII.3' is at the bottom right. + +**Figure II.3 – Typical examples of fibre distribution boxes used as FDH and MDUB for low fibre density applications** + +## **II.3 Attributes of FTDB** + +Various attributes are listed in Table II.1 to specify different types of FTDBs. + +**Table II.1 – Attributes of FTDB** + +| SN | Attributes | Type X | +|----|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------| +| 1 | Material of construction (PC, ABS, PC+ABS, CRCA, SMC)
PC = Polycarbonate
PP = Polypropylene
ABS = Acrylonitrile butadiene styrene
SMC = Sheet molding compound
CRCA = Cold rolled close annealed | User to specify | +| 2 | IP rating (as per [IEC 60529]) IP 55, IP 65 | IP 55 for IN and IP 65 for OA | +| 3 | Installation location (indoor/outdoor/both) | User to specify | +| 4 | Fixture type (wall mount/pole mount/both) | User to specify | +| 5 | UV proof | For OA | +| 6 | Color of the box | User to specify | +| 7 | Fireproof (Yes/No) | User to specify | + +**Table II.1 – Attributes of FTDB** + +| SN | Attributes | Type X | +|----|--------------------------------------------------------------------------------|-----------------------------| +| 8 | Operating temperature | –5 to + 55 °C for OA and IN | +| 9 | Length (mm) without entry/exit ports | User to specify | +| 10 | Width (mm) | User to specify | +| 11 | Depth (mm) | User to specify | +| 12 | Minimum thickness of the box body (mm) | User to specify | +| 13 | Cover flip type (hinge/push/slotting, etc.) | User to specify | +| 14 | Location of fixture point | User to specify | +| 15 | Number of incoming cables | User to specify | +| 16 | Diameter of incoming cable (mm) | User to specify | +| 17 | Fibre count of incoming cable | User to specify | +| 18 | Number of tubes in incoming cable | User to specify | +| 19 | Fibres/tube in incoming cable | User to specify | +| 20 | Length of tubes to be stored from entry cable | Minimum 1 meter | +| 21 | Number of tubes to be dropped from incoming cable | User to specify | +| 22 | Number of fibres to be dropped from incoming cable | User to specify | +| 23 | Number of outgoing cables | User to specify | +| 24 | Diameter/dimension of outgoing cable (mm) | User to specify | +| 25 | Fibre count of outgoing cable | User to specify | +| 26 | Number of tubes in outgoing cable | User to specify | +| 27 | Fibres/tube in outgoing cable | User to specify | +| 28 | Length of tubes/fibres/buffered fibres/drop cable to be stored from exit cable | Minimum 1 meter | +| 29 | Number of splitters | User to specify | +| 30 | Ratio of splitters (1:8/1:16/1:32/2:8/2:16/2:32, etc.) | User to specify | +| 31 | Splitter type (bare/cassette) | User to specify | +| 32 | Type of connectors in the splitter (in case of cassette splitter) | User to specify | +| 33 | Input/output length of pigtails in splitter in case of bare splitter | User to specify | +| 34 | Input/output length of buffered fibre in splitter in case of bare splitter | User to specify | +| 35 | Number of splice trays required | User to specify | +| 36 | Maximum splice capacity | User to specify | +| 37 | Maximum splice capacity per tray | User to specify | +| 38 | Provision for mid-span of cable (Yes/No) | User to specify | +| 39 | Maximum patching capacity | User to specify | +| 40 | Box security provision | User to specify | + +## Bibliography + +- [b-ITU-T G-Sup.59] Recommendation ITU-T G-Sup.59 (2016), *Guidance on optical fibre and cable reliability*. +- [b-TEC/GR/TX/FTB] *Generic Requirements (GR) for Fibre Termination and Distribution Box (For FTTH Applications)*, Telecommunications Engineering Centre (Department of Telecommunications), Govt. of India. + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of 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(01/2024)** + +SERIES L: Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant + +Optical infrastructures – General aspects and network design + +# --- **Topologies for optical access network** + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue circular emblem with a stylized globe and the letters 'ITU' in white. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +### **Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant** + +| | | +|--------------------------------------------------------|--------------------| +| OPTICAL FIBRE CABLES | L.100-L.199 | +| OPTICAL INFRASTRUCTURES | L.200-L.299 | +| Infrastructure including node elements (except cables) | L.200-L.249 | +| General aspects and network design | L.250-L.299 | +| MAINTENANCE AND OPERATION | L.300-L.399 | +| PASSIVE OPTICAL DEVICES | L.400-L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430-L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000-L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200-L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300-L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400-L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500-L.1599 | +| CIRCULAR AND SUSTAINABLE CITIES AND COMMUNITIES | L.1600-L.1699 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700-L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# Recommendation ITU-T L.250 + +# Topologies for optical access network + +## Summary + +Recommendation ITU-T L.250 describes the optical access network to be used in the design and construction of fibre to the x (FTTx), centralized – radio access networks (C-RAN) for mobile communications, and other network services. It deals mainly with access network architectures and the upgrading or new deployment of optical fibre to optical access networks. + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|------------------|------------|-------------|--------------------| +| 1.0 | ITU-T L.250/L.90 | 2012-02-13 | 15 | 11.1002/1000/11531 | +| 2.0 | ITU-T L.250 | 2024-01-13 | 15 | 11.1002/1000/15808 | + +## Keywords + +Network architecture, optical access network, optical fibre and cable distribution. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2024 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|------------|----------------------------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 4 | +| 3.1 | Terms defined elsewhere ..... | 4 | +| 3.2 | Terms defined in this Recommendation..... | 4 | +| 4 | Abbreviations and acronyms ..... | 5 | +| 5 | Conventions ..... | 6 | +| 6 | Concept of layers within a network architecture ..... | 6 | +| 6.1 | Optical fibre..... | 6 | +| 6.2 | Cables, passive components and passive nodes ..... | 7 | +| 6.3 | Structural facility ..... | 7 | +| 7 | Access network architectures ..... | 8 | +| 7.1 | General ..... | 8 | +| 7.2 | Optical fibre level architecture ..... | 8 | +| 7.3 | Cable level architecture ..... | 11 | +| 7.4 | Convergence architecture ..... | 13 | +| 8 | Cabling characteristics..... | 14 | +| 9 | Deployment method for high reliability ..... | 15 | +| 10 | Upgrading the optical network ..... | 16 | +| 11 | Optical transmission performance for optical access networks..... | 17 | +| 12 | Optical safety ..... | 17 | +| 13 | Installation of optical access network..... | 17 | +| 13.1 | Initial stage ..... | 18 | +| 13.2 | Growth stage..... | 18 | +| 13.3 | Mature stage ..... | 18 | +| 13.4 | Final stage..... | 19 | +| Appendix I | – Installation and maintenance issues ..... | 20 | +| I.1 | Optical network maintenance support, monitoring and testing system..... | 20 | +| I.2 | Digitized management of physical infrastructures in optical access network ..... | 20 | +| I.3 | Electrical power supply ..... | 20 | +| I.4 | Electrical safety ..... | 20 | +| | Bibliography..... | 21 | + +# Introduction + +Progress in telecommunications technologies has led to the active development of many kinds of broadband services such as data and video communication using access networks. It is important that high-speed broadband optical access networks be developed economically to provide services directly to subscribers, connected things and mobile communication devices. To provide these services in a timely manner, it is necessary to construct optical access networks quickly, efficiently and cost-effectively. + +In the past decade, progress in the application of optical fibre technology in local access networks for fibre to the home (FTTH) has provided substantial technical and economic benefits in several countries. The development of "smart city", "Internet of things" (IoT) and "industrial Internet" has broadened the scope of areas by which the optical network can access the services. 5G mobile communication network construction is in progress in many countries and centralized – radio access networks (C-RAN) could save costs on base station sites, equipment, room rent and energy compared with traditional distributed – radio access network (D-RAN). + +Here, an optical access network contains a network of optical fibre cables that extend from a carrier's central office to cabinets, buildings, individual homes, apartment blocks, business offices, workshops, smart city equipment boxes, smart poles or mobile telecommunication base stations. + +###### Recommendation ITU-T L.250 + +## Topologies for optical access network + +# 1 Scope + +This Recommendation defines optical single-mode fibre access network architectures and provides information on planning new deployments and upgrading existing networks. Moreover, this Recommendation considers optical transmission performance and optical safety which depends on the architecture design of an optical access network. + +This Recommendation covers: + +- definitions and general features of fibre level and cable level architectures that have been used to meet different system objectives; +- convergence architectures for upgrading the performance of the optical access network; +- physical components within the network architectures; +- optical safety requirements; +- installation issues. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T G.652] Recommendation ITU-T G.652 (2016), *Characteristics of a single-mode optical fibre and cable*. +- [ITU-T G.657] Recommendation ITU-T G.657 (2016), *Characteristics of a bending-loss insensitive single-mode optical fibre and cable*. +- [ITU-T G.662] Recommendation ITU-T G.662 (2005), *Generic characteristics of optical amplifier devices and subsystems*. +- [ITU-T G.664] Recommendation ITU-T G.664 (2012), *Optical safety procedures and requirements for optical transmission systems*. +- [ITU-T G.671] Recommendation ITU-T G.671 (2019), *Transmission characteristics of optical components and subsystems*. +- [ITU-T G.694.1] Recommendation ITU-T G.694.1 (2020), *Spectral grids for WDM applications: DWDM frequency grid*. +- [ITU-T G.694.2] Recommendation ITU-T G.694.2 (2003), *Spectral grids for WDM applications: CWDM wavelength grid*. +- [ITU-T G.698.4] Recommendation ITU-T G.698.4 (2018), *Multichannel bi-directional DWDM applications with port agnostic single-channel optical interfaces*. +- [ITU-T G.698.5] Recommendation ITU-T G.698.5 (2024), *Multichannel DWDM applications with single-channel optical interfaces in the O-band*. + +- [ITU-T G.698.6] Recommendation ITU-T G.698.6 (2024), *Multichannel WDM applications with single-channel optical interfaces in the O-band.* +- [ITU-T G.982] Recommendation ITU-T G.982 (1996), *Optical access networks to support services up to the ISDN primary rate or equivalent bit rates.* +- [ITU-T G.983.1] Recommendation ITU-T G.983.1 (2005), *Broadband optical access systems based on Passive Optical Networks (PON).* +- [ITU-T G.983.2] Recommendation ITU-T G.983.2 (2005), *ONT management and control interface specification for B-PON.* +- [ITU-T G.983.3] Recommendation ITU-T G.983.3 (2001), *A broadband optical access system with increased service capability by wavelength allocation.* +- [ITU-T G.983.4] Recommendation ITU-T G.983.4 (2001), *A broadband optical access system with increased service capability using dynamic bandwidth assignment.* +- [ITU-T G.983.5] Recommendation ITU-T G.983.5 (2002), *A broadband optical access system with enhanced survivability.* +- [ITU-T G.984.1] Recommendation ITU-T G.984.1 (2008), *Gigabit-capable passive optical networks (GPON): General characteristics.* +- [ITU-T G.984.2] Recommendation ITU-T G.984.2 (2019), *Gigabit-capable Passive Optical Networks (G-PON): Physical Media Dependent (PMD) layer specification.* +- [ITU-T G.984.3] Recommendation ITU-T G.984.3 (2014), *Gigabit-capable passive optical networks (G-PON): Transmission convergence layer specification.* +- [ITU-T G.984.4] Recommendation ITU-T G.984.4 (2008), *Gigabit-capable passive optical networks (G-PON): ONT management and control interface specification.* +- [ITU-T G.984.5] Recommendation ITU-T G.984.5 (2022), *Gigabit-capable passive optical networks (G-PON): Enhancement band.* +- [ITU-T G.984.6] Recommendation ITU-T G.984.6 (2008), *Gigabit-capable passive optical networks (GPON): Reach extension.* +- [ITU-T G.984.7] Recommendation ITU-T G.984.7 (2010), *Gigabit-capable passive optical networks (GPON): Long reach.* +- [ITU-T G.985] Recommendation ITU-T G.985 (2003), *100 Mbit/s point-to-point Ethernet based optical access system.* +- [ITU-T G.986] Recommendation ITU-T G.986 (2010), *1 Gbit/s point-to-point Ethernet-based optical access system.* +- [ITU-T G.987] Recommendation ITU-T G.987 (2012), *10-Gigabit-capable passive optical network (XG-PON) systems: Definitions, abbreviations and acronyms.* +- [ITU-T G.987.1] Recommendation ITU-T G.987.1 (2016), *10-Gigabit-capable passive optical network (XG-PON): General requirements.* +- [ITU-T G.987.2] Recommendation ITU-T G.987.2 (2023), *10-Gigabit-capable passive optical networks (XG-PON): Physical media dependent (PMD) layer specification.* +- [ITU-T G.987.3] Recommendation ITU-T G.987.3 (2014), *10-Gigabit-capable passive optical networks (XG-PON): Transmission convergence (TC) layer specification.* +- [ITU-T G.987.4] Recommendation ITU-T G.987.4 (2012), *10-Gigabit-capable passive optical networks (XG-PON): Reach extension.* + +- [ITU-T G.989] Recommendation ITU-T G.989 (2015), *40-Gigabit-capable passive optical networks (NG-PON2): Definitions, abbreviations and acronyms.* +- [ITU-T G.989.1] Recommendation ITU-T G.989.1 (2013), *40-Gigabit-capable passive optical networks (NG-PON2): General requirements.* +- [ITU-T G.989.2] Recommendation ITU-T G.989.2 (2019), *40-Gigabit-capable passive optical networks 2 (NG-PON2): Physical media dependent (PMD) layer specification.* +- [ITU-T G.989.3] Recommendation ITU-T G.989.3 (2021), *40-Gigabit-capable passive optical networks (NG-PON2): Transmission convergence layer specification.* +- [ITU-T G.9802.1] Recommendation ITU-T G.9802.1 (2021), *Wavelength division multiplexed passive optical networks (WDM PON): General requirements.* +- [ITU-T G.9804.1] Recommendation ITU-T G.9804.1 (2019), *Higher speed passive optical networks – Requirements.* +- [ITU-T G.9804.2] Recommendation ITU-T G.9804.2 (2021), *Higher speed passive optical networks – Common transmission convergence layer specification.* +- [ITU-T G.9804.3] Recommendation ITU-T G.9804.3 (2021), *50-Gigabit-capable passive optical networks (50G-PON): Physical media dependent (PMD) layer specification.* +- [ITU-T G.9806] Recommendation ITU-T G.9806 (2020), *Higher-speed bidirectional, single fibre, point-to-point optical access system (HS-PtP).* +- [ITU-T G.9807.1] Recommendation ITU-T G.9807.1 (2023), *10-Gigabit-capable symmetric passive optical network (XGS-PON).* +- [ITU-T G.9807.2] Recommendation ITU-T G.9807.2 (2017), *10 Gigabit-capable passive optical networks (XG(S)-PON): Reach extension.* +- [ITU-T L.100] Recommendation ITU-T L.100 (2021), *Optical fibre cables for duct and tunnel application.* +- [ITU-T L.101] Recommendation ITU-T L.101/L.43 (2015), *Optical fibre cables for buried application.* +- [ITU-T L.102] Recommendation ITU-T L.102/L.26 (2015), *Optical fibre cables for aerial application.* +- [ITU-T L.103] Recommendation ITU-T L.103 (2016), *Optical fibre cables for indoor applications.* +- [ITU-T L.104] Recommendation ITU-T L.104/L.67 (2006), *Small count optical fibre cables for indoor applications.* +- [ITU-T L.105] Recommendation ITU-T L.105/L.87 (2010), *Optical fibre cables for drop applications.* +- [ITU-T L.107] Recommendation ITU-T L.107/L.78 (2008), *Optical fibre cable construction for sewer duct applications.* +- [ITU-T L.108] Recommendation ITU-T L.108 (2018), *Optical fibre cable elements for microduct blowing installation application.* +- [ITU-T L.110] Recommendation ITU-T L.110 (2017), *Optical fibre cables for direct surface application.* +- [ITU-T L.111] Recommendation ITU-T L.111 (2020), *Optical fibre cables for in-home applications.* + +- [ITU-T L.200] Recommendation ITU-T L.200/L.51 (2003), *Passive node elements for fibre optic networks - General principles and definitions for characterization and performance evaluation.* +- [ITU-T L.201] Recommendation ITU-T L.201 (2021), *Performance requirements for passive optical nodes: Sealed closures for outdoor environments.* +- [ITU-T L.202] Recommendation ITU-T L.202/L.50 (2010), *Requirements for passive optical nodes: Optical distribution frames for central office environments.* +- [ITU-T L.206] Recommendation ITU-T L.206 (2017), *Requirements for passive optical nodes: outdoor optical cross-connect cabinet.* +- [ITU-T L.208] Recommendation ITU-T L.208 (2019), *Requirements for passive optical nodes: fibre distribution boxes.* +- [ITU-T L.209] Recommendation ITU-T L.209 (2022), *Requirements for fibre optic network terminal box (FONT).* +- [ITU-T L.210] Recommendation ITU-T L.210 (2022), *Requirements for passive optical nodes: Optical wall outlets and extender boxes.* +- [ITU-T L.302] Recommendation ITU-T L.302/L.40 (2000), *Optical fibre outside plant maintenance support, monitoring and testing system.* +- [ITU-T L.310] Recommendation ITU-T L.310 (2016), *Optical fibre maintenance depending on topologies of access networks.* +- [ITU-T L.400] Recommendation ITU-T L.400/L.12 (2022), *Optical fibre splices.* +- [ITU-T L.401] Recommendation ITU-T L.401/L.31 (1996), *Optical fibre attenuators.* +- [ITU-T L.402] Recommendation ITU-T L.402/L.36 (2015), *Single mode fibre optic connectors.* +- [ITU-T L.403] Recommendation ITU-T L.403/L.37 (2007), *Optical branching components (non-wavelength selective).* +- [ITU-T L.404] Recommendation ITU-T L.404 (2017), *Field mountable single-mode optical fibre connectors.* +- [ITU-T X.200] Recommendation ITU-T X.200 (1994) ISO/IEC 7498-1(1994), *Information technology – Open Systems Interconnection – Basic Reference Model: The basic model.* + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +For the purpose of this Recommendation, the definitions given in [ITU-T G.652], [ITU-T G.662], [ITU-T G.664], [ITU-T G.671], [ITU-T G.694.1], [ITU-T G.694.2], [ITU-T G.982], [ITU-T G.983.1] to [ITU-T G.983.5], [ITU-T G.984.1] to [ITU-T G.984.7], [ITU-T G.987], [ITU-T L.105], [ITU-T L.200] and [ITU-T L.201] apply. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 access point:** A drop optical cable from subscriber premises is connected to a distribution cable at this point. + +**3.2.2 building entry point (BEP):** Allows the transition from outdoor to indoor cable. The type of transition may be a splice or a remountable connection. + +- 3.2.3 cable level architecture:** Describes the access network topology from cable level, indicating the relation of fibre and cable distribution by illustrating how fibres are distributed across one or multiple cable connection points. +- 3.2.4 central office area:** This area is the section between the optical line terminal (OLT) and the optical distribution frame (ODF) in the central office (CO). +- 3.2.5 customer premises equipment (CPE):** This is any active device, e.g., set-top-box, that provides the end-user with certain services (high-speed data, TV, telephony, etc.). The optical network terminal (ONT) and CPE may be integrated. +- 3.2.6 distribution area:** The area between the distribution point and the access point. +- 3.2.7 distribution point:** Optical cables from some access points in a distribution area are gathered at this point and connected to the feeder cable from the central office (CO). +- 3.2.8 feeder area:** The area between the optical distribution frame (ODF) and the distribution point. +- 3.2.9 floor distributor (FD):** The floor distributor is an optional element which allows the transition from the vertical to the horizontal indoor cable. +- 3.2.10 optical fibre level architecture:** Architectures indicate the fibre distribution topology from the central office (CO) to every end user or far-end equipment. +- 3.2.11 optical network termination (ONT):** Terminates the optical network at customer premises. It includes an electro-optical converter. The ONT and customer premises equipment (CPE) may be integrated. +- 3.2.12 optical telecommunication outlet (OTO):** This is a fixed connecting device where the fibre optic indoor cable terminates. The optical telecommunication outlet provides an optical interface to the equipment cord of the optical network termination (ONT)/ customer premises equipment (CPE). +- 3.2.13 user area:** The area between the access point and optical network unit (ONU)/ optical network termination (ONT) in subscriber premises. +- 3.2.14 user equipment:** The user equipment, TV, phone, personal computer, etc., allows the user to access the services. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|------------------------------------------------------------------------------| +| BEP | Building Entry Point | +| CO | Central Office | +| CPE | Customer Premises Equipment | +| C-RAN | Centralized Radio Access Network | +| CWDM | Coarse Wavelength Division Multiplexing | +| DWDM | Dense Wavelength Division Multiplexing | +| FD | Floor Distributor | +| FDB | Fibre Distribution Box | +| FTTH | Fibre To The Home | +| FTTR | Fibre To The Room | +| FTTx | Fibre To The x, where 'x' stands for the final location on the end-user side | +| HSP | Higher Speed Passive Optical Networks | + +| | | +|---------|-------------------------------------------| +| IoT | Internet of Things | +| ISP | Internet Service Provider | +| LCP | Local Convergence Point | +| NAP | Network Access Point | +| NG-PON2 | Next Generation Passive Optical Network 2 | +| NID | Network Interface Device | +| ODF | Optical Distribution Frame | +| OLT | Optical Line Terminal | +| ONT | Optical Network Terminal | +| ONU | Optical Network Unit | +| OSP | Outside Plant | +| OSS | Operations Support System | +| OTO | Optical Telecommunication Outlet | +| OXC | Optical Cross Connect | +| PON | Passive Optical Network | +| TDM | Time Division Multiplexing | +| WDM | Wavelength Division Multiplexing | + +# 5 Conventions + +None. + +# 6 Concept of layers within a network architecture + +The layers are classified according to the [ITU-T X.200] OSI ISO reference model. + +This specification refers only to the physical layer (layer 1). + +## 6.1 Optical fibre + +A suitable choice of optical fibre and splice loss criteria should be made. Single-mode fibre compliant with [ITU-T G.652] is the most appropriate choice for a wide range of telecommunication services in the feeder and local distribution network since this fibre benefits from economy of scale and has long-term potential for future services. [ITU-T G.657] category A fibre is compatible with [ITU-T G.652] fibre and has better macro-bending performance to support small bending radii installation conditions in the drop and home / building network. [ITU-T G.657] category B fibre, with smaller bending radii than category A fibre, is mainly utilized at the end of the access networks particularly inside or near buildings, or in fibre management systems. The user should note that uncertainty regarding the splice values and compatibility issues may be increased when using [ITU-T G.657] category B fibres together with [ITU-T G.652] fibres or [ITU-T G.657] category A fibres. + +With current usage of single-mode fibres, it is recommended to utilize fusion splice technology to make splices, and the typical allowed splice loss is less than 0.2 dB (see [ITU-T L.400] for further information). + +## 6.2 Cables, passive components and passive nodes + +Cable design should be determined to suit the network architecture adopted. Cables as described in [ITU-T L.100] to [ITU-T L.102] and [ITU-T L.107] to [ITU-T L.111] could be used for outside plant (OSP) cabling in the feeder and distribution network; cables as described in [ITU-T L.105] could be used for drop network; cable as described in [ITU-T L.111] could be used for home/building network; cables as described in [ITU-T L.103] and [ITU-T L.104] could be used as jumpers for short distance connection between passive components. + +Optical fibre connectors as described in [ITU-T L.402] and [ITU-T L.404] could be used for termination of user cables in fibre to the x (FTTx) and similar applications. Passive node hardware and housings, with fibre organizers / fibre management systems, are used to protect and manage fibre joints/connections and passive components. Sealed closures for outdoor environments should comply with [ITU-T L.201]; optical distribution frames for CO environments should comply with [ITU-T L.202]; outdoor optical cross-connect cabinets should comply with [ITU-T L.206]; fibre distribution boxes should comply with [ITU-T L.208]; housing to keep both active and passive elements in a single box should comply with [ITU-T L.209]; optical wall outlets and extender boxes used in the users' premise should comply with [ITU-T L.210]. Other passive optical plant hardware and housings should have specific environmental constraints, see [ITU-T L.200]. A line diagram of the optical fibres, cables and passive components along with their relevant ITU-T Recommendations is shown in Figure 1. + +![Figure 1: Optical fibres, cables and passive components and ITU-T Recommendations. This is a line diagram showing the flow of optical signals from a Central office to a Home/building, categorized into Inside plant and Outside plant (OSP).](ff0952ef692c9d960ce5f6708bcc9711_img.jpg) + +The diagram illustrates the optical network architecture from the Central office to the Home/building, divided into Inside plant and Outside plant (OSP) segments. + +- Central office (Inside plant):** Contains OLT, Branching component, Distribution frame, and Jumpers. ITU-T Recommendations: Fibre (ITU-T G.652, ITU-T G.657), Optical connectors and adapters (ITU-T L.402 and ITU-T L.404), WDM/Splitters (ITU-T G.671, ITU-T G.694.1, ITU-T G.694.2), Jumpers (ITU-T L.103-104). +- Feeder (Outside plant):** Contains ISP vault/OSE, OSP fibre cable, OSP hardware, and OSP closures. ITU-T Recommendations: ISP vault/OSE (ITU-T L.200, ITU-T L.202), OSP fibre cable (ITU-T L.100-102, ITU-T L.107-110), OSP hardware (ITU-T L.200, ITU-T L.206), OSP closures (ITU-T L.200, ITU-T L.201, ITU-T L.400). +- Distribution (Outside plant):** Contains WDM/Splitters, NAP, and OSP cable assembly. ITU-T Recommendations: WDM/Splitters (ITU-T G.671, ITU-T G.694.1, ITU-T G.694.2), NAP (ITU-T L.200, ITU-T L.201), OSP cable assembly (ITU-T L.200). +- Drop (Outside plant):** Contains Drop cable. ITU-T Recommendation: Drop cable (ITU-T L.105). +- Home/building (Inside plant):** Contains In-home, Outlets, ONT, NID, FD, OTO, and CPE. ITU-T Recommendations: In-home (ITU-T L.111), Outlets (ITU-T L.210), NID (ITU-T L.208, ITU-T L.209). + +Labels at the bottom indicate the segments: Central office, Feeder, Distribution, Drop, Home/building, Inside plant, and Outside plant (OSP). The diagram is labeled L.250(24). + +Figure 1: Optical fibres, cables and passive components and ITU-T Recommendations. This is a line diagram showing the flow of optical signals from a Central office to a Home/building, categorized into Inside plant and Outside plant (OSP). + +Figure 1 – Optical fibres, cables and passive components and ITU-T Recommendations + +Pre-terminated cable assemblies and plug-and-play passive nodes could be used for quick and efficient installation of the network, by reduction or avoiding of the difficulties posed by field fibre splicing. + +## 6.3 Structural facility + +The optical access network architecture originally evolved from copper networks has the form of a star topology radiating from the CO. Optical fibre plant architectures have led to the development of new designs and plant layouts that are far more advanced than those of legacy copper networks. The optical cable plant uses a mixture of aerial, underground, duct and microduct technologies for deployment. For legacy networks, newer microduct applications could be used in the trench, existing ducts, aerial applications and for access to buildings for installation of cables with air-assisted techniques. + +# 7 Access network architectures + +## 7.1 General + +In order to select or design an optical access network, telecommunication companies and local service providers should mainly consider: + +- 1) scalability (cable fibre count, spare fibre, split ratio, etc.); +- 2) survivability (physical redundancy, security, supervisory system, etc.); +- 3) functionality (bit rate, transmission distance, etc.); +- 4) cost (construction and maintenance costs); +- 5) upgrade (increase transmission capacity, increase transmission length, increase number of customers, connected things, etc.). + +When designing or constructing an optical access network, telecommunication companies should select and use one or more of the following architectures, based on the optical access network requirements in each region. These include: + +- Optical fibre level architecture + - Optical fibre point-to-point + - Optical fibre point-to-multipoint + - Ring +- Cable level architecture + +## 7.2 Optical fibre level architecture + +### 7.2.1 Optical fibre point-to-point architecture + +The basic configuration for an optical fibre point-to-point architecture is shown in Figure 2. This architecture distributes one or more dedicated fibres from the CO to every potential user or far-end equipment, for example, an optical line terminal (OLT) connects to a subscriber optical network unit (ONU)/optical network terminal (ONT), and forms a dedicated point-to-point channel (1:1). Therefore, many fibres are required because every potential end user/equipment location needs a dedicated fibre back to the signal source. Splitters may be deployed in CO, offering high flexibility and port efficiencies and optical cross-connect cabinets can be used in the outside plant if dedicated pad or pole space accommodations are provided. + +This configuration has low optical loss and provides the maximum distance between COs and customers and other end equipment. The insertion loss of the optical line is a sum of fibre, splice and connector losses. This architecture has a high bandwidth capability and provides an easy upgrade path. + +![Diagram of Optical fibre point-to-point architecture showing OLT, NAP, and ONT components and distances.](d17f75945bbb3feb84a153ecfedb9b81_img.jpg) + +The diagram illustrates an optical fibre point-to-point architecture. On the left, a circle labeled 'OLT' is positioned above a horizontal line representing the optical fibre. Below the OLT is the text 'Central office'. The fibre extends to the right, where it branches into two separate circles labeled 'ONT'. Between the OLT and the ONTs, there are two small squares labeled 'NAP'. Above the fibre line, three distance segments are indicated with double-headed arrows: 'Feeder distance (km)' from the OLT to the first NAP, 'Distribution distance (km)' from the first NAP to the second NAP, and 'Drop distance (m)' from the second NAP to the ONTs. A bracket below the fibre line spans from the OLT to the ONTs and is labeled 'Optical fibre'. In the bottom right corner, the text 'L.250(24)' is present. + +Diagram of Optical fibre point-to-point architecture showing OLT, NAP, and ONT components and distances. + +**Figure 2 – Optical fibre point-to-point architecture** + +### 7.2.2 Optical fibre point-to-multipoint architecture + +The basic configuration of an optical fibre point-to-multipoint network is shown in Figures 3, 4 and 5. The feature of the optical fibre point-to-multipoint network is that branching unit(s) are placed in the channel between an OLT and several ONUs/ONTs. + +The location of a branching unit is the most important item in terms of network design and construction. Two types of branching units can be used in the network. In one type, the wavelength selective device, has a wavelength multiplexer and de-multiplexer; in the other type is a non-wavelength selective device or splitter. A non-wavelength selective branching unit (splitter) increases the insertion loss and reduces the transmission distance as the number of branches is increased. In contrast, a wavelength selective branching unit is mainly used in wavelength division multiplexing (WDM) systems. The insertion loss does not increase greatly but it can be difficult to control and manage the wavelengths used when the number of branches is increased. The channel between ONU and ONU/ONT is a point-to-multipoint channel with non-wavelength selective branching unit(s), and can use a point-to-point channel with only wavelength selective branching unit(s). Non-wavelength selective and wavelength selective branching unit(s) can also be used in one network. + +When a branching unit is installed in a CO, at least one fibre is connected between the CO and an ONU/ONT. Therefore, many fibres are installed and distributed from the CO. Moreover, the environmental conditions for the (fibre optic) branching component have wider tolerance specifications due to the device being installed inside a CO. + +A branching unit can be installed in a housing in the outside plant or inside a customer building. The number of fibres between an OLT and a fibre optic branching unit are reduced. However, the environmental conditions for the branching unit may require tighter tolerance specifications because it may be located in the outside plant, on the outside walls of a building, or inside a basement room. + +The basic configuration for an optical fibre point-to-multipoint architecture network with 1-level branching is shown in Figure 3. In this architecture a dedicated fibre connects each end user/equipment to a local convergence cabinet which contains a branching component (example splitter or WDM). This architecture is commonly deployed where a large central office serves concentrated pockets of end user / equipment locations. This configuration deploys feeder cables that run from the CO to an OSP cabinet with a branching unit, then distribution cables serve downstream network access points (NAPs) which then connect to end users/equipment on a (1:1) ratio. The insertion loss of the optical line is the sum of fibre, splice, branching unit and connector losses. This architecture can easily change split ratios or WDM channels and transport technologies, and the centralized branching location optimizes optical line terminal efficiencies. + +![Diagram of an optical fibre point-to-multipoint network with 1-level branching.](9ae17964ddd9b814c7d905b1af2fddf2_img.jpg) + +The diagram illustrates a 1-level branching optical fibre network. On the left, an 'OLT' (Optical Line Terminal) is located in a 'Central office'. A 'Feeder distance (km)' of optical fibre connects the OLT to a 'Branching component'. From the branching component, two 'Distribution distance (km)' of optical fibre lead to two separate 'NAP' (Network Access Point) units. Each NAP is connected to an 'ONT' (Optical Network Terminal) by a 'Drop distance (m)' of optical fibre. The ONTs are located in end-user locations. A bracket at the bottom labeled 'Optical fibre' spans from the OLT to the ONTs. The label 'L.250(24)' is in the bottom right corner. + +Diagram of an optical fibre point-to-multipoint network with 1-level branching. + +**Figure 3 – Optical fibre point-to-multipoint network (in the case of 1-level branching)** + +The basic configuration for an optical fibre point-to-multipoint architecture (with 2-level branching) is shown in Figure 4. In this architecture a dedicated fibre drop cable connects each end user/equipment to the closest downstream terminal access point. This configuration deploys a relatively lean fibre architecture with fewer fibre-count feeder and distribution cables. The lower + +fibre-count distribution cables serve downstream end users/equipment on a (1:1) ratio. The insertion loss of the optical line is the sum of fibre, splice, branching unit and connector losses. This architecture has flexible split ratio combinations of $1 \times 2$ , $1 \times 4$ , and $1 \times 8$ splitters and can reduce splitter access point size due to the distributed split locations. + +![Figure 4: Optical fibre point-to-multipoint network (in the case of 2-level branching).](5cab96b2d23174c25919840ecd50aa48_img.jpg) + +This diagram illustrates a 2-level branching optical fibre network. On the left, an 'OLT' (Optical Line Terminal) is located within a 'Central office'. A single 'Optical fibre' cable extends from the OLT for a 'Feeder distance (km)'. It then reaches a 'Branching component'. From this component, the fibre splits into two parallel paths. Each path contains another 'Branching component'. After the second branching components, each path splits again into four parallel lines, each ending at a 'NAP' (Network Access Point). These four NAPs are connected to two 'ONT' (Optical Network Terminal) units. The distance from the first branching component to the second is labeled 'Distribution distance (km)'. The final short segments from the NAPs to the ONTs are labeled 'Drop distance (m)'. The label 'L.250(24)' is in the bottom right corner. + +Figure 4: Optical fibre point-to-multipoint network (in the case of 2-level branching). + +**Figure 4 – Optical fibre point-to-multipoint network (in the case of 2-level branching)** + +By deploying branching units with asymmetrical branching ratios (non-wavelength selective or wavelength selective), the branches would have a main branch carrying a large part of the optical power or wavelengths and several branches that share the rest; the optical fibre point-to-multipoint network could be a distributed tap architecture. The basic configuration for a distributed tap architecture is shown in Figure 5. This architecture is suitable for sparsely populated areas or fringe/land locked areas where future growth is unlikely. This architecture deploys dedicated fibre connecting each subscriber to the splitter terminal. Asymmetric tap branching terminals are concatenated in series leveraging a single OLT for signal. This configuration deploys extremely low-fibre-count cables as distribution cables. The lower fibre-count distribution cables serve downstream end user/equipment on a (1:1) ratio. The insertion loss of the optical line is the sum of fibre, splice, branching unit and connector losses. This architecture has flexible split ratio combinations of $1 \times 2$ , $1 \times 4$ , and $1 \times 8$ splitters and can reduce splitter access point size due to the distributed split locations. + +![Figure 5: Optical fibre point-to-multipoint network (in the case of 3-level distributed tap architecture).](16152cf1d84aea10848758f51a91ff6a_img.jpg) + +This diagram illustrates a 3-level distributed tap architecture. An 'OLT' in a 'Central office' is connected via an 'Optical fibre' for a 'Feeder distance (km)'. The fibre then passes through a series of three 'Branching component' units, each connected by a 'Distribution distance (km)' segment. At each branching component, a 'tap' is made to a pair of 'NAP' (Network Access Point) units. Each pair of NAPs is connected to a pair of 'ONT' (Optical Network Terminal) units. The vertical distance from the main fibre line to the NAPs is labeled 'Drop distance (m)'. The label 'L.250(24)' is in the bottom right corner. + +Figure 5: Optical fibre point-to-multipoint network (in the case of 3-level distributed tap architecture). + +**Figure 5 –Optical fibre point-to-multipoint network (in the case of 3-level distributed tap architecture)** + +### 7.2.3 Optical fibre ring architecture + +The basic configuration of an optical fibre ring network is shown in Figures 6a and 6b. This starts and ends at the same OLT in a CO and uses two or more fibres to connect to ONUs/ONTs. For optical fibre point-to-point ring networks as shown in Figure 6a, a very large number of fibres are installed and distributed from CO to customers, connected things or mobile communication base stations. By contrast, the multiple-type ring networks as shown in Figure 6b, can reduce the number of distributed + +fibres compared to point-to-point ring networks. The advantages of ring networks are high reliability with redundancy and ease of maintenance for alternative routing. + +![Diagram of a ring network (Optical fibre point-to-point type)](c85ded401105f62f2d6ff26b3b5eb4af_img.jpg) + +This diagram illustrates a ring network topology using optical fibre. At the bottom left, a circle labeled 'OLT' is connected to a 'Central office'. From the OLT, a 'Feeder distance (km)' of optical fibre extends to a square node labeled 'NAP'. From this NAP, a 'Drop distance (m)' of fibre leads to a circle labeled 'ONT'. From this ONT, another 'Drop distance (m)' of fibre leads to a second square node labeled 'NAP'. From this second NAP, the fibre continues to a third circle labeled 'ONT' on the right. Finally, the fibre returns to the OLT at the bottom left, completing the ring. A bracket at the bottom of the diagram is labeled 'Optical fibre'. The reference 'L.250(24)' is shown in the bottom right corner. + +Diagram of a ring network (Optical fibre point-to-point type) + +**Figure 6a – Ring network (Optical fibre point-to-point type)** + +![Diagram of a ring network (Multiple type)](8307f6b04df072c9332f9987e034272c_img.jpg) + +This diagram illustrates a multiple type ring network topology using optical fibre. At the bottom left, a circle labeled 'OLT' is connected to a 'Central office'. From the OLT, a 'Feeder distance (km)' of optical fibre extends to a square node labeled 'NAP'. From this NAP, a 'Drop distance (m)' of fibre leads to a circle labeled 'ONT'. From this ONT, another 'Drop distance (m)' of fibre leads to a second square node labeled 'NAP'. From this second NAP, the fibre continues to a circle labeled 'ONT' on the right. From this ONT, the fibre leads to a third circle labeled 'ONT' at the bottom. Finally, the fibre returns to the OLT at the bottom left, completing the ring. A bracket at the bottom of the diagram is labeled 'Optical fibre'. The reference 'L.250(24)' is shown in the bottom right corner. + +Diagram of a ring network (Multiple type) + +**Figure 6b – Ring network (Multiple type)** + +## 7.3 Cable level architecture + +Cable level architecture is one of the key considerations in access network design because it is strongly related to construction cost and the performance of the access network. The cable level architecture is the physical cabling of a logical topology across all the cable connection points in an + +area, and the cable topology at each point forms the basic unit of the cable network. Generally, a cable level architecture is realized by combining multi types of the basic topology units, and the whole access network is realized by combining multi types of cable level architectures. + +The basic topology units fall into four types: direct-connection unit, mid-span unit, branching unit, and ring unit. For direct-connection unit, the fibres are connected directly at cable joint by splices or jumpers on a (1:1) ratio to extend the length of cable line or allocate the fibres to demand locations without introducing too much insertion loss. For mid-span units, the optical fibres are accessed from the mid-span of the cable at demand location. This unit is suitable for areas where the demand is unexpected or the demand scale is small. For branching units, a branching component (e.g. $1 \times 2$ , $1 \times 4$ , $1 \times 8$ ) is utilized to distribute the fibres from one cable to multi-cables, increasing the number of fibres and expanding the capacity of the network. For ring units, the fibres are accessed from the mid-span of the cable or from the splice/ jumper enclosure and form a closed loop line. These units are generally used to form a cable ring architecture to attain high reliability. General schematics of the basic topology units are summarized in Figure 7. + +![Figure 7: Schematics of basic cable topology units. a) Mid-span unit: shows two cable segments connected by a splice/jumper. b) Branching unit: shows a cable segment branching into multiple cables via a branching component. c) Direct-connection unit: shows two cable segments connected by splices/jumpers. d) Ring unit: shows a cable segment connected to a ring structure via splices/jumpers. The diagram is labeled L.250(24).](dfe556fea00682b09a59427aaf72051c_img.jpg) + +The diagram illustrates four basic cable topology units: + + +- a) Mid-span unit:** Two cable segments are shown connected end-to-end by a splice or jumper. +- b) Branching unit:** A single cable segment is shown branching into multiple cables (indicated by three lines and an ellipsis) through a branching component. +- c) Direct-connection unit:** Two cable segments are shown connected end-to-end by splices or jumpers. +- d) Ring unit:** A cable segment is shown connected to a ring structure (represented by a dashed box with arrows) via splices or jumpers. + + The diagram is labeled 'L.250(24)' in the bottom right corner. + +Figure 7: Schematics of basic cable topology units. a) Mid-span unit: shows two cable segments connected by a splice/jumper. b) Branching unit: shows a cable segment branching into multiple cables via a branching component. c) Direct-connection unit: shows two cable segments connected by splices/jumpers. d) Ring unit: shows a cable segment connected to a ring structure via splices/jumpers. The diagram is labeled L.250(24). + +**Figure 7 – Schematics of basic cable topology units: a) Mid-span unit; b) Branching unit; c) Direct-connection unit; d) Ring unit.** + +The cable level architectures fall into two types: star and ring topologies. A logical star topology can be deployed as a point-to-point cabling or as a gradual decrease cabling physical architecture. Both of these architectures have trade-offs with regard to construction cost, flexibility and reliability. When high reliability in the network is required, the ring architecture is used for its ease of establishing redundant cable routes between distribution areas. The ring topology increases the reliability of the access network and the architecture can be adopted as a topology that accommodates various services with different reliability requirements. + +General features of cable level architectures and the basic topology units each architecture may include are summarized in Table 1. + +**Table 1 – General features of cable level architectures** + +| | Star | Star (gradual decrease) | Ring | +|----------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Physical cabling | Diagram of Star physical cabling: A central black node labeled 'Node' is connected to four white nodes by straight lines. The label 'L.250(24)' is in the bottom right corner. | Diagram of Star (gradual decrease) physical cabling: A central black node labeled 'Node' is connected to four white nodes. The connections are curved lines that decrease in length from the center outwards. The label 'L.250(24)' is in the bottom right corner. | Diagram of Ring physical cabling: A central black node labeled 'Node' is connected to four white nodes in a continuous loop. The label 'L.250(24)' is in the bottom right corner. | +| Logical (Data flow) | Diagram of Star logical data flow: A central black node labeled 'Node' is connected to four white nodes by straight lines. The label 'L.250(24)' is in the bottom right corner. | Diagram of Star (gradual decrease) logical data flow: A central black node labeled 'Node' is connected to four white nodes by straight lines. The label 'L.250(24)' is in the bottom right corner. | Diagram of Ring logical data flow: Four white nodes are connected in a circular loop. A black node labeled 'Node' is on the bottom of the loop. The label 'L.250(24)' is in the bottom right corner. | +| Basic topology units may include | Direct-connection unit, Mid-span unit, Branching unit | Direct-connection unit, Mid-span unit, Branching unit | Direct-connection unit, Mid-span unit, Branching unit, Ring unit | +| Initial construction cost | Moderate | Low | High | +| Repetitive construction cost | Moderate | High | Low | +| Reliability | Moderate | Low | High | + +## 7.4 Convergence architecture + +The previous optical fibre level and cable level architectures in clauses 7.1, 7.2 and 7.3 can be converged in order to meet the various requirements of accommodating broadband services. The convergence architecture is an extended network architecture using active/passive node (w/ or w/o splitters) and another or the same architecture. Examples of converged architecture based on point-to-point ring architecture and ring architecture are illustrated in Figures 8a and 8b, respectively. Figure 8a is an example of an upgrade network combining ring and point-to-multipoint architectures to efficiently accommodate increased demand in a service area. The 1st level of branching component is connected with a ring network from CO and it can be connected to either the 2nd level of the branching component or directly to ONUs/ONTs. 1st and 2nd level branching components have flexible split ratio combinations typically $2 \times N$ and $1 \times N$ (where $N = 2, 4, 8, 16$ ). Figure 8b shows concatenated ring architecture which can provide a highly reliable redundant fibre on a different route anywhere in the service area. It is recommended to not have many converged levels in the architecture since this can raise channel loss and network complexity. + +In some applications, the ONTs can also be an active device that could also work as the OLT of a local area optical access sub-network. For example, fibre to the room (FTTR) in living units or offices, and optical local networks in factories or industrial premises. In these cases, the access network is extended by the sub-networks. The sub-networks could have their own topologies, making the overall network a multi-level convergence architecture. + +![Diagram of a converged network (Point-to-multipoint) showing an OLT in a central office connected via a feeder cable to a node (splices, OXC) which then connects to an ONT. The feeder cable also connects to a branching node (splitter or WDM), which is connected to multiple ONTs via distribution and drop cables. The entire setup is labeled 'Optical fibre cable' and 'L.250(24)'.](b6671cfafda3820aafe9a24fa7a4d8c7_img.jpg) + +Diagram illustrating a converged network (Point-to-multipoint) configuration. An Optical Line Terminal (OLT) located in a Central office is connected via a Feeder cable to a Node (Splices, OXC). This Node is connected to an ONT. The Feeder cable also connects to a Branching node (Splitter or WDM), which is connected to multiple ONTs via Distribution and drop cables. The entire setup is labeled 'Optical fibre cable' and 'L.250(24)'. + +Diagram of a converged network (Point-to-multipoint) showing an OLT in a central office connected via a feeder cable to a node (splices, OXC) which then connects to an ONT. The feeder cable also connects to a branching node (splitter or WDM), which is connected to multiple ONTs via distribution and drop cables. The entire setup is labeled 'Optical fibre cable' and 'L.250(24)'. + +**Figure 8a – Converged network (Point-to-multipoint)** + +![Diagram of a converged network (Concatenated ring) showing an OLT in a central office connected via a feeder cable to a node (splices, OXC) which then connects to an ONT. The feeder cable also connects to a distribution node (splices, OXC), which is connected to a drop cable and another node (splices, OXC) which then connects to an ONT. The entire setup is labeled 'Optical fibre cable' and 'L.250(24)'.](5445597cceefaca1ac89e710fe339325_img.jpg) + +Diagram illustrating a converged network (Concatenated ring) configuration. An Optical Line Terminal (OLT) located in a Central office is connected via a Feeder cable to a Node (Splices, OXC). This Node is connected to an ONT. The Feeder cable also connects to a Distribution node (Splices, OXC), which is connected to a Drop cable and another Node (Splices, OXC) which then connects to an ONT. The entire setup is labeled 'Optical fibre cable' and 'L.250(24)'. + +Diagram of a converged network (Concatenated ring) showing an OLT in a central office connected via a feeder cable to a node (splices, OXC) which then connects to an ONT. The feeder cable also connects to a distribution node (splices, OXC), which is connected to a drop cable and another node (splices, OXC) which then connects to an ONT. The entire setup is labeled 'Optical fibre cable' and 'L.250(24)'. + +**Figure 8b – Converged network (Concatenated ring)** + +# 8 Cabling characteristics + +The cabling characteristics for an overall end-to-end network from the CO to user's home could be defined in the following main parts: + +- Optical distribution frame (ODF) in CO; + +- Feeder cabling between the ODF and the local convergence point (LCP, or service area interface, SAI); +- LCP (e.g., a cabinet); +- Distribution cabling between the LCP and a drop point (DP) or a network interface device (NID) at building entrance point (BEP); +- DP (e.g., a fibre distribution box (FDB)) or NID (e.g., an ODF at building telecommunication room); +- Drop cabling from a DP to an optical telecommunication outlet (OTO), possibly including floor distributor (FD); +- OTO; +- Equipment cord between an OTO and ONT / ONU. Specific in-home cabling can be deployed in the apartment / customer site instead of the equipment cord. + +Each customer is connected with one to four fibres from the NID to the OTO. Typically, one to four fibres are either collected in one indoor cable or they can also be taken from multiple fibre cables. + +A more detailed reference model for cabling of this network is shown in Figure 9: + +![Figure 9: Detailed reference end-to-end network from the central office to user's home. The diagram shows a sequence of components connected by lines representing cabling. From left to right: ODF (Optical Distribution Frame), LCP (Local Convergence Point), DP/NID (Drop Point/Network Interface Device), FD (Floor Distributor), OTO (Optical Telecommunication Outlet), and ONU/ONT (Optical Network Unit/Network Terminal). Above the components, labels indicate the cabling segments: 'Feeder cabling' between ODF and LCP, 'Distribution cabling' between LCP and DP/NID, 'Drop cabling' between DP/NID and OTO (spanning over the FD), and 'Equipment cord/In-home cabling' between OTO and ONU/ONT. The FD component is shown with a dashed border. A label 'L.250(24)' is present below the ONU/ONT component.](79e1709a7317ead45379cbb8ff3ba802_img.jpg) + +Figure 9: Detailed reference end-to-end network from the central office to user's home. The diagram shows a sequence of components connected by lines representing cabling. From left to right: ODF (Optical Distribution Frame), LCP (Local Convergence Point), DP/NID (Drop Point/Network Interface Device), FD (Floor Distributor), OTO (Optical Telecommunication Outlet), and ONU/ONT (Optical Network Unit/Network Terminal). Above the components, labels indicate the cabling segments: 'Feeder cabling' between ODF and LCP, 'Distribution cabling' between LCP and DP/NID, 'Drop cabling' between DP/NID and OTO (spanning over the FD), and 'Equipment cord/In-home cabling' between OTO and ONU/ONT. The FD component is shown with a dashed border. A label 'L.250(24)' is present below the ONU/ONT component. + +**Figure 9 – Detailed reference end-to-end network from the central office to user's home** + +In other applications, OLTs/ONUs replace certain points of LCP, DP/NID, FD or OTO shown in Figure 8 and terminate the optical access networks. They may be located in equipment boxes, on poles, on towers or in telecommunication rooms of buildings. The networks accordingly consist of part of the cabling system in Figure 9. + +# 9 Deployment method for high reliability + +Access networks that can accommodate business communication service and/or C-RAN for mobile communication should offer high reliability specified in a service level agreement. A highly reliable access network can be realized by the use of redundant fibre deployment. The reliability of the cable network is determined by what kind of accidental risk event is possible and then mitigation is to be assured by the deployment of a redundant fibre/cable architecture. Five recommendations are possible as redundant fibre/cable deployment methods: + +- 1) fibres in one cable element (fibre bundle, fibre ribbon, buffer tube, etc.); +- 2) different cable elements of one cable; +- 3) different cables on the same route; +- 4) different cables on the different routes from one CO; +- 5) different cables on the different routes from different COs. + +The reliability of each redundant recommendation is summarized in Table 2. It is recommended to select a redundancy policy based on the risk. + +**Table 2 – Redundant recommendation versus service interruption** + +| Accidental risk event | 1) | 2) | 3) | 4) | 5) | +|----------------------------------------------------------------|-----------|-----------|-----------|-----------|-----------| +| OLT or ONT / ONU failure | o | o | o | o | o | +| Obstacle relocation work | x | o | o | o | o | +| Accidental harm | x | x | o | o | o | +| Route breakage by natural disaster | x | x | x | o | o | +| Power outage at CO | x | x | x | x | o | +| NOTE – o and x mean supported and not supported, respectively. | | | | | | + +When an unexpected event happens, possible protection / restoration methods include: + +- 1) Optical connectors allow craft to cross-connect around failures (obviously slow); +- 2) Optical switches are used to reroute signals over the diverse paths (reasonably fast); +- 3) Active equipment switching, such as type B protection in time division multiplexing passive optical networks (TDM-PONs), or wavelength protection in WDM-PONs; +- 4) Full duplex protection, where there are two redundant fibre links, and the active equipment uses the best one. + +# 10 Upgrading the optical network + +When the transmission capacity, transmission length and/or number of customers, connected things increases, it will become necessary to upgrade the optical network. At such a time, telecommunication companies should consider the contents of Table 3 and select the appropriate method to upgrade the optical network. + +**Table 3 – Network upgrade methods** + +| | Optical fibre point-to-point architecture | Optical fibre ring architecture | Optical fibre point-to-multipoint architecture | +|--------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Increase transmission capacity |
  • • Use higher rate line systems
| |
  • • Use higher bit rate systems (e.g., NG-PON2 or HSP systems)
  • • Coexistence of multiple system on access network (see [ITU-T G.9805])
  • • Reduce the split ratio (example from 1×32 to 1×16)
  • • Use WDM system (CWDM, DWDM)
| +| Increase transmission length |
  • • Reduce number of optical fibre / cable links by using, for example, blown fibre / cable techniques
  • • Use optical fibre amplifier
| |
  • • Reduce number of optical fibre links by using, for example blown fibre / cable techniques
  • • Use WDM system (use (fibre-optic) branching component with wavelength multiplexer and de-multiplexer)
  • • Reduce number of branches (split ratio) or change to point-to-point network
| + +**Table 3 – Network upgrade methods** + +| | Optical fibre point-to-point architecture | Optical fibre ring architecture | Optical fibre point-to-multipoint architecture | +|------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------| +| | | |
  • Use optical fibre amplifier
| +| Increase number of customers |
  • Change to optical fibre point-to-multipoint architecture and increase number of branches
  • Install new cable
|
  • Install new cable
  • Change to convergence architecture
|
  • Increase number of branches (split ratio)
  • Install new cable
| +| Increase reliability |
  • Provide redundant fibre (Note)
|
  • Change to convergence architecture (concatenated ring architecture)
  • Provide redundant fibre (Note)
|
  • Change to ring architecture
  • Provide redundant fibre (NOTE)
| +| NOTE – See clause 9. | | | | + +With a multiple type ring architecture and an optical fibre point-to-multipoint architecture, when the optical network is upgraded, all the ONUs/ONTs connected to one OLT must be upgraded simultaneously. + +# **11 Optical transmission performance for optical access networks** + +Optical access networks should be designed to meet the performance requirements (attenuation range, return loss, chromatic dispersion, etc.) as described in [ITU-T G.982], [ITU-T G.984.1] to [ITU-T G.984.7], [ITU-T G.986], [ITU-T G.987], [ITU-T G.987.1] to [ITU-T G.987.4], [ITU-T G.989], [ITU-T G.989.1] to [ITU-T G.989.3], [ITU-T G.9802.1], [ITU-T G.9806], [ITU-T G.9807.1], [ITU-T G.9807.2], [ITU-T G.9804.1] to [ITU-T G.9804.3], [ITU-T G.698.4], [ITU-T G.698.5] and [ITU-T G.698.6]. + +The calculation of the total network optical loss will consider [ITU-T G.982]. + +# **12 Optical safety** + +Optical safety should consider [ITU-T G.664]. + +# **13 Installation of optical access network** + +Generally, there are four stages in the installation of an optical access network for an area or a country, namely initial stage, growth stage, mature stage and final stage as illustrated in Figure 10. The topologies for each stage as well as the deployment of optical fibres cables and passive components should be carefully considered to suit each stage since they are strongly related to the cost, upgrade and performance of the access network. + +![Figure 10: Progressive increase in number of FTTx subscribers. A line graph showing the number of subscribers over time, divided into four stages: Initial, Growth, Mature, and Final. The curve rises through the first three stages and declines in the final stage.](9ce50bc10864dc86e1cdee4be08f1897_img.jpg) + +The graph illustrates the lifecycle of FTTx subscribers over time. The vertical axis represents the 'Number of subscribers' and the horizontal axis represents 'Time'. The curve is divided into four distinct phases by vertical lines: + + +- Initial stage:** The beginning of the curve where subscriber numbers are low and increasing slowly. +- Growth stage:** The phase where the curve rises steeply, indicating rapid subscriber growth. +- Mature stage:** The phase where the curve reaches its peak and begins to level off. +- Final stage:** The phase where the curve shows a downward trend, indicating a decrease in the number of subscribers. + + A small label 'L.250(24)' is present at the bottom right of the graph area. + +Figure 10: Progressive increase in number of FTTx subscribers. A line graph showing the number of subscribers over time, divided into four stages: Initial, Growth, Mature, and Final. The curve rises through the first three stages and declines in the final stage. + +**Figure 10 – Progressive increase in number of FTTx subscribers** + +## 13.1 Initial stage + +In the initial stage, the demand for optical fibre will be dispersed over a wide area and the number of subscribers may be small. Therefore, effective and economical approaches need to be considered for optical fibre distribution. For example, the point-to-point topology can be introduced to meet demands from the few subscribers while the 1-level point-to-multipoint topology supports relatively concentrated subscribers. Access points need to be carefully allocated to achieve low construction cost and workability. Furthermore, it is important to take demand growth into account during network design and construction. Measures like spare fibres or additional branching points can be introduced to handle future demands. Technologies that support the deferment of costs for subsequent up-scaling of fibre capacity could be considered. + +## 13.2 Growth stage + +In the growth stage, the demand will occur randomly and frequently over a wide area, and the response to the demands should be quick and efficient. In particular, in the area between the last access point and individual home, apartment, business building, etc., which is the so called "the last mile of network", it is very important to design the network architecture to achieve easy optical fibre distribution because this part of the access network occupies the largest scale of optical fibres. Furthermore, effective and economical optical fibre distribution scheme for rural areas is needed since most demand in the growth stage will be widely dispersed in rural areas. + +Additionally, as the access network will experience rapid network infrastructure expansion including optical fibres, cables and passive elements in the growth stage, the ability to manage and maintain the infrastructures effectively is critical. For example, there will be a need to use the optical fibre network maintenance support, monitoring and testing system described in [ITU-T L.302] and [ITU-T L.310]. + +Moreover, it is anticipated that overlaying fibre networks into areas of legacy metallic networks will eventually occur, presenting challenges for both aerial and underground optical fibre cables deployment. Therefore, it will be important to use existing facilities such as cable ducts for the effective and economical installation of optical fibre cables as the available facilities will be scarce. For example, several optical fibre cables could be installed in a cable duct. Consideration could be given to active cable duct management solutions to ensure their future economical usability. + +## 13.3 Mature stage + +In the mature stage, the emerging demand for new optical fibres will be small and a huge amount of network infrastructures will already be in place. Therefore, effective management and maintenance of network infrastructures becomes the most important issue. Building a network infrastructure database is a widely used method to manage the infrastructure and maintenance concerns, which are described in [b-ITU-T L.360]. + +In addition, subscribers who require very high reliability should be provided with two or more fibres using a ring network. Telecommunication companies should take account of the above factors in each stage when selecting the appropriate architecture and network infrastructures to construct access networks. + +## **13.4 Final stage** + +In the final stage, demographic considerations may suppress demand for optical fibre and the plant and land could be re-used for different purposes, e.g., industrial, commercial, retail or residential, or a mix of these uses. Such events may be common in urban areas. It is likely that there will be a threshold at which systems and networks will become uneconomic to operate and need to be decommissioned. + +# Appendix I + +## Installation and maintenance issues + +(This appendix does not form an integral part of this Recommendation.) + +### I.1 Optical network maintenance support, monitoring and testing system + +Optical network maintenance support, monitoring and testing is described in [ITU-T L.302]. The maintenance wavelength shall be selected in accordance with [ITU-T L.301]. + +When using an optical fibre ring network or an optical fibre point-to-multipoint network using a (fibre optic) branching components, or an active node in an outside plant or in a building, apartment block or residential premises, the optical network maintenance support, monitoring and testing is described in [ITU-T L.310]. The maintenance wavelength shall be selected in accordance with [ITU-T L.301]. + +### I.2 Digitized management of physical infrastructures in optical access network + +Passive components and facilities make up the main part of the optical access network. Digitizing the passive physical infrastructures by creating uniform data structures for the passive components and facilities, together with their spatial and connection relationships, would bring greater convenience for network planning, management, and maintenance. By digitization, the optical access network could be mapped to, and visualized in an operations support system (OSS) as described in [b-ITU-T L.360]. ID tags (e.g., QR code, RFID) mounted on or embedded in the network elements would make the digitization quick and error-free, see [b-ITU-T L.361]. Passive node elements with automated tag detection in optical access networks are described in [b-ITU-T L.207]. By scanning ID tags, information saved in the tags or in the OSSs could be read by the personal terminals of field engineers. When the elements are installed, the positioning information of personal terminals could also be used to initialize location data of the network elements in the OSSs. + +### I.3 Electrical power supply + +The electrical power supply and battery backup to an ONU or an active node should be selected by considering the outage rate of commercial power suppliers, the cost when using commercial power suppliers, the time to repair a power source failure, and the reliability requirements of the services being provided, as described in [b-ITU-T L.203]. Where it is not easy to get power from a nearby source, optical/metallic hybrid cables as described in [b-ITU-T L.109.1] could be used for remote power supply. A combined housing as described in [ITU-T L.209] to keep both active elements such as ONT, battery and its charge controller (power supply) as well as passive elements such as fibre patch panel, connectors, splitters and fibre splice trays, instead of having multiple separate boxes for active and passive elements could be used. This combined housing is especially helpful to service providers for FTTx applications in areas where ownership, space, safe custody and availability of power supply source are hurdles to deployment. + +### I.4 Electrical safety + +Electrical safety should consider [b-ITU-T K.51]. + +# Bibliography + +- [b-ITU-T K.51] Recommendation ITU-T K.51 (2016), *Safety criteria for telecommunication equipment.* +- [b-ITU-T L.109.1] Recommendation ITU-T L.109.1 (2022), *Type-II optical/electrical hybrid cables for access points and other terminal equipment.* +- [b-ITU-T L.203] Recommendation ITU-T L.203/L.44 (2000), *Electric power supply for equipment installed as outside plant.* +- [b-ITU-T L.207] Recommendation ITU-T L.207 (2018), *Passive node elements with automated ID tag detection.* +- [b-ITU-T L.301] Recommendation ITU-T L.301 (2000), *Maintenance wavelength on fibres carrying signals.* +- [b-ITU-T L.360] Recommendation ITU-T L.360/L.80 (2008), *Operations support system requirements for infrastructure and network elements management using ID technology.* +- [b-ITU-T L.361] Recommendation ITU-T L.361/L.64 (2012), *ID tag requirements for infrastructure and network elements management.* + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|----------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.28-200210-I_PDF-E/07f537f57749b75157f742525e6a8dbc_img.jpg b/marked/L/T-REC-L.28-200210-I_PDF-E/07f537f57749b75157f742525e6a8dbc_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..d73aee8766daa0412b866341e7fdf53a2b50844d --- /dev/null +++ b/marked/L/T-REC-L.28-200210-I_PDF-E/07f537f57749b75157f742525e6a8dbc_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:af0b8ec1140b43b567648064d06f657b7fd0875dbe0e52fc1be603113e0a9e0c +size 37760 diff --git a/marked/L/T-REC-L.28-200210-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg b/marked/L/T-REC-L.28-200210-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg new file mode 100644 index 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a/marked/L/T-REC-L.28-200210-I_PDF-E/f4fdd410cdb84df81274da55721e56fb_img.jpg b/marked/L/T-REC-L.28-200210-I_PDF-E/f4fdd410cdb84df81274da55721e56fb_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..5bbf4e12e8ed3c07bcb8c3ac37c418ce7f00625f --- /dev/null +++ b/marked/L/T-REC-L.28-200210-I_PDF-E/f4fdd410cdb84df81274da55721e56fb_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:fd18eeb5e7414bf9f2eab25edd06d712749f102d1eac996601dea5533e07cd96 +size 26518 diff --git a/marked/L/T-REC-L.28-200210-I_PDF-E/raw.md b/marked/L/T-REC-L.28-200210-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..8466cbd3b55ad87a8c48400f0647d3474e6df59f --- /dev/null +++ b/marked/L/T-REC-L.28-200210-I_PDF-E/raw.md @@ -0,0 +1,227 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features the letters 'ITU' in a bold, sans-serif font, superimposed on a stylized globe with intersecting lines. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.28** + +(10/2002) + +SERIES L: CONSTRUCTION, INSTALLATION AND +PROTECTION OF CABLES AND OTHER ELEMENTS OF +OUTSIDE PLANT + +--- + +**External additional protection for marinized +terrestrial cables** + +ITU-T Recommendation L.28 + +--- + + + +# **ITU-T Recommendation L.28** + +# **External additional protection for marinized terrestrial cables** + +## **Summary** + +This Recommendation describes the external protection devices which can be utilized during/after the laying or during/after the reparation of Marinized Terrestrial Cables (MTC). + +## **Source** + +ITU-T Recommendation L.28 was prepared by ITU-T Study Group 6 (2001-2004) and approved under the WTSA Resolution 1 procedure on 29 October 2002. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2003 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +| | Page | +|---------------------------------------------------------|------| +| 1 Introduction ..... | 1 | +| 2 References..... | 1 | +| 3 Burial and external protection devices ..... | 1 | +| Appendix I – Examples of external cable protection..... | 3 | +| Appendix II – Bibliography ..... | 5 | + + + +## External additional protection for marinized terrestrial cables + +## 1 Introduction + +A marinized terrestrial cable is an underwater optical fibre cable, based on a conventional multi-fibre terrestrial cable core construction and protected to withstand the marine environment. It is designed for unrepeaters applications, that is, without underwater line amplifiers, hence without the need of power feeding for submerged equipment and has been tested for use in non-aggressive shallow waters, with a varying repair capability. + +The difference with respect to a repeaterless submarine cable can be found in the definition given in ITU-T Rec. G.972. + +Cables are designed with a predicted lifetime, taking into account either cable replacement or a certain number of repairs. + +For shallow-water cables, the probability of failures is higher than for deep-water application due to environmental phenomena (for example, sea-wave motion, underwater earthquakes and landslides, etc.) and human activities affecting the seabed (for example, fishing, laying and maintenance of other services and cables). + +In addition to the various armour usually adopted for the cable construction – for example Rocky Armour (RA), steel wire armouring such as single armour (SA) or double armour (DA), additional external protections could be adopted if needed. Such protections can be applied both approaching the coast in shallow water and on shore in the portion between the water edge and the Beach Joint, or along the cable route where external factors or seabed features could damage the cables. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- ITU-T Recommendation G.972 (2000), *Definition of terms relevant to optical fibre submarine cable systems*. +- ITU-T Recommendation G.976 (2000), *Test methods applicable to optical fibre submarine cable systems*. + +## 3 Burial and external protection devices + +Burial and external protection devices have to be combined in the shore approach and in shallow water in relationship to the seabed feature and human activities. Cable external protection devices and or trenching have to be utilized in areas where some fishing activities or vessel/ship anchoring, etc., could damage the cable itself in spite of the protection already existing in the cable structure construction. + +Therefore, where it is necessary to meet the predicted lifetime and the cable reliability requirements during or after the installation/reparation of cable, the following protection devices are adopted: + +- 3.1) *In the shore portion (generally defined between the Beach Joint and the 5 m water depth)* + +The cable should be protected with cast iron shells and buried at least 2-3 m. + +In the beach up to the water edge, the cable, where necessary, should also be covered with concrete flat bricks and moored by chains to an anchor block or directly to the beach manhole if present. + +If rocky bottom is present in the very shallow water portion, the cable should be anchored to the rock with crossed chains by using set pins. In the case of sand, concrete bags should also be used as extra protection to cover the cable and avoid grabbing or dragging along this section. + +### 3.2) *In the shallow water portion (generally defined between 5 m and 30-40 m water depth)* + +The burial depth, trenching method and external protection devices depend on seabed features and human activities in the interested marine area. + +#### 3.2.1) *In case of soft bottom (for example, loose sand)* + +The cable should be buried at least 1 m (for example, by divers or by using jetting methods). In deeper water, along the cable route where possible or convenient, the burial should be performed using plowing or jetting machinery. Usually, due to its softness and loosing, the sand will naturally backfill the trench. + +#### 3.2.2) *In case of hard bottom* + +If the hardness of the soil (for example, rocks, biotherm) does not allow burial, the cable should be protected and secured (for example, by means of cast-iron shells duly secured to the soil in order to avoid movements due to sea-wave motion). In areas where these shells are liable to be damaged, the articulated pipe formed by them should be protected by concrete-gravel bags clamped to each other. + +Where several cables are foreseen to be concentrated in a rocky shore approach, more additional protection is needed to prevent damage between the cables due to the environment (e.g., friction effects, etc). This protection (commonly known as tube) is in the form of helically wound steel types/wires on each cable at the time of installation. The protection is needed for up to 100 m from the water's edge and in water depths up to 5 m. The pipes can be fixed and protected by mattresses and backfilled using same original rocks. + +A proper combination of the above-mentioned methods should be applied when the seabed features change along this section. + +Appendix I shows some examples of possible external cable protection devices. + +### 3.3) *Other cable or marine service crossing* + +When a crossing is foreseen, the cable route and the cable protection, as well as the installation method, have to be determined by the parties concerned (owners of the plant). As a general rule, the crossings between cables shall be performed as near to a right angle (90 degrees) as possible. It is highly recommended that crossing angles minor of 45 degrees be avoided in order to ensure proper operational and maintenance activities. Moreover, cable crossing types shall be chosen to avoid as much as possible the risk of abrasion. For example, if an armoured cable has to be installed over an existing Light Weight (LW) cable, then special coverings shall be applied to armoured cables or special crossing methods have to be implemented where this situation is deemed unavoidable; on the contrary, if a LW cable has to be installed over an existing armoured cable, then it is advisable that a short length of armoured cable be adopted in correspondence with the crossing point. + +In the case of a crossing of an already installed cable by gas pipelines, oil pipelines, power cables, etc., the cable should be suitably protected with devices (for example, mattresses or rock dumping) able to prevent any damage during the laying, maintenance and recovery operations of such plants. With this in mind, action should be coordinated between those responsible for the two services. + +Similar protection devices should be adopted when a cable has to cross an already existing pipeline if: + +- the pipeline carries warm substances (for example, oil ducts in the proximity of the wells), the temperature of which could modify or damage the external sheath or the tar protecting the steel wire armouring of the cable in proximity of the contact point between cable and pipeline; +- the contact between pipeline and cable could lead to the generation of corrosion due to galvanic currents if cathode protection is not used; +- mechanical friction between pipeline and cable, due to the water motion, could damage the cable. + +## Appendix I + +### Examples of external cable protection + +![Two diagrams illustrating external cable protection methods. The top diagram shows a cable running horizontally across a seabed, covered by a sediment layer. Above the cable, there are several 'Bags' (sand cement bags) and 'Cast-iron shells' placed over it. The bottom diagram shows a cable running vertically through a sediment layer, with 'Bags' and 'Cast-iron shells' surrounding it. The seabed is labeled 'Sea bottom' and the underlying rock is labeled 'Rock'.](a86610f7a0e579fec9f34dea52fa088b_img.jpg) + +The image contains two cross-sectional diagrams of cable protection. The top diagram shows a cable running horizontally. Above the cable, there is a 'Sediment layer'. Overlaid on the cable are several 'Bags' (sand cement bags) and 'Cast-iron shells'. The cable itself is labeled 'Cable'. The bottom diagram shows a cable running vertically through a 'Sediment layer' and 'Sea bottom' into a 'Rock' layer. The cable is surrounded by 'Bags' and 'Cast-iron shells'. The cable is labeled 'Cable'. The bottom right of the diagram is labeled 'L.028\_F01'. + +Two diagrams illustrating external cable protection methods. The top diagram shows a cable running horizontally across a seabed, covered by a sediment layer. Above the cable, there are several 'Bags' (sand cement bags) and 'Cast-iron shells' placed over it. The bottom diagram shows a cable running vertically through a sediment layer, with 'Bags' and 'Cast-iron shells' surrounding it. The seabed is labeled 'Sea bottom' and the underlying rock is labeled 'Rock'. + +Figure I.1/L.28 – Cable protected with cast-iron shells and sand cement bags + +![Diagram I.2/L.28 showing a cross-section of a cable on the sea bottom. The cable is suspended in a 'Cable free span' above the 'Sea bottom'. The sea bottom consists of a layer of 'Sand' over 'Rock'. 'Bags' (sand-cement bags) are positioned under, laterally, and above the cable to reduce the free span. The bags are marked with 'X' and '#' symbols.](a5ee5c23b6dc52ec1d724b76d5a5f58f_img.jpg) + +Diagram I.2/L.28 showing a cross-section of a cable on the sea bottom. The cable is suspended in a 'Cable free span' above the 'Sea bottom'. The sea bottom consists of a layer of 'Sand' over 'Rock'. 'Bags' (sand-cement bags) are positioned under, laterally, and above the cable to reduce the free span. The bags are marked with 'X' and '#' symbols. + +![Diagram I.3/L.28 showing a cross-section of a cable on the sea bottom. The cable is now resting on the 'Sea bottom', which consists of 'Sand' over 'Rock'. 'Bags' are positioned under, laterally, and above the cable to reduce the free span. The bags are marked with 'X' and '#' symbols. A label 'L.028_F02' is present in the bottom right corner.](f4fdd410cdb84df81274da55721e56fb_img.jpg) + +Diagram I.3/L.28 showing a cross-section of a cable on the sea bottom. The cable is now resting on the 'Sea bottom', which consists of 'Sand' over 'Rock'. 'Bags' are positioned under, laterally, and above the cable to reduce the free span. The bags are marked with 'X' and '#' symbols. A label 'L.028\_F02' is present in the bottom right corner. + +**Figure I.2/L.28 – Protection performed by positioning sand-cement bags under, laterally and above the cable** + +![Underwater photograph showing a cable protected by several sand-cement bags. The bags are stacked and positioned around the cable on the seabed. A label 'L.028_T03' is present in the bottom right corner.](07f537f57749b75157f742525e6a8dbc_img.jpg) + +Underwater photograph showing a cable protected by several sand-cement bags. The bags are stacked and positioned around the cable on the seabed. A label 'L.028\_T03' is present in the bottom right corner. + +**Figure I.3/L.28 – Photo of an example of cable free span reduced using concrete bags** + +![A photograph showing a cable protected by a series of stacked, light-colored, cylindrical cast-iron shells. The cable is buried in a trench, and the surrounding soil is visible. The shells are stacked vertically, providing a continuous protective barrier.](967c30813761a8952ecc5e16bf42ea45_img.jpg) + +A photograph showing a cable protected by a series of stacked, light-colored, cylindrical cast-iron shells. The cable is buried in a trench, and the surrounding soil is visible. The shells are stacked vertically, providing a continuous protective barrier. + +A photograph showing a cable protected by a series of stacked, light-colored, cylindrical cast-iron shells. The cable is buried in a trench, and the surrounding soil is visible. The shells are stacked vertically, providing a continuous protective barrier. + +L.028\_T04 + +**Figure I.4/L.28 – Photo of an example of external cable protection using cast-iron shells and additional sand concrete bags** + +## **Appendix II** + +## **Bibliography** + +- ITU-T Handbook (2001), *Marinized Terrestrial Cables*. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure and Internet protocol aspects | +| Series Z | Languages and general software aspects for telecommunication systems | + +\*23098\* \ No newline at end of file diff --git a/marked/L/T-REC-L.29-200201-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg b/marked/L/T-REC-L.29-200201-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..104a57fbd03964ffd2520508b2be42e03343d20f --- /dev/null +++ b/marked/L/T-REC-L.29-200201-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:f2468dfa77e8d32611a5fe8a2ebb904676994eeb54463226fd865698560c960c +size 8232 diff --git a/marked/L/T-REC-L.29-200201-I_PDF-E/raw.md b/marked/L/T-REC-L.29-200201-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..ef7747aa3eaaf7f16d2986c4af9e1fa7be834e55 --- /dev/null +++ b/marked/L/T-REC-L.29-200201-I_PDF-E/raw.md @@ -0,0 +1,164 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.29** + +(01/2002) + +SERIES L: CONSTRUCTION, INSTALLATION AND +PROTECTION OF CABLES AND OTHER ELEMENTS OF +OUTSIDE PLANT + +--- + +**As-laid report and maintenance/repair log for +marinized terrestrial cable installation** + +ITU-T Recommendation L.29 + +--- + + + +# **ITU-T Recommendation L.29** + +## **As-laid report and maintenance/repair log for marinized terrestrial cable installation** + +## **Summary** + +This Recommendation describes the documentation/information that Companies, involved in the installation, maintenance/repair of Marinized Terrestrial Cables, should provide to the Purchasers. + +### **Source** + +ITU-T Recommendation L.29 was prepared by ITU-T Study Group 6 (2001-2004) and approved under the WTSA Resolution 1 procedure on 13 January 2002. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2002 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +###### Page + +| | | | +|---|------------------------------|---| +| 1 | Introduction..... | 1 | +| 2 | References..... | 1 | +| 3 | As-Laid Report ..... | 1 | +| 4 | Maintenance/Repair Log ..... | 2 | + + + +## **As-laid report and maintenance/repair log for marinized terrestrial cable installation** + +# **1 Introduction** + +A marinized terrestrial cable is an underwater optical fibre cable construction, based on a conventional multi-fibre terrestrial cable core protected to withstand the marine environment, designed for unrepeatable applications, that is, without underwater line amplifiers, hence without the need to carry electrical power and tested for use in non-aggressive shallow waters, with a varying repair capability. + +The difference with respect to a repeaterless submarine cable can be found in the definition given, for such a cable, in ITU-T Rec. G.972. + +In proximity of the landing points there are often many cables coming from various routes. In the shore-end portions, the cables and related protections such as burials, articulated steel pipes, etc. are closer and closer. Moreover, often the actual route is quite different from that foreseen as the laying reference route, as designed according to the various surveys, and the related documents are not updated. This situation could negatively affect subsequent installations and maintenance operations of cables and other services. + +In order to update charts, the national Hydrographic Institute, or any other local Authority, has to be provided with the as-laid and as-built cable route information both after completion of the installation works, and after any repair if significant route changes occur. This will enable the proper design of project routes for future underwater services and cables, and allow safe maintenance activities over existing lines so that overlaying and plants damage can be avoided. + +# **2 References** + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. + +- ITU-T Recommendation G.972 (2000), *Definition of terms relevant to optical fibre submarine cable systems*. +- ITU-T Recommendation G.976 (2000), *Test methods applicable to optical fibre submarine cable systems*. + +# **3 As-Laid Report** + +The companies in charge of the installation of cables in shallow waters, especially close to the landing points of sea, lake and river shores, should provide the Purchasers with an *As-laid Report* after the completion of the work and a *Maintenance/Repair Log* after any repair or replacement. + +The *as-laid report* should contain, at least, the following information: + +- detailed As-laid position list (both in geographical and plane coordinates with progressive Kilometer Posts along the route) with all the relevant points such as Turning Points, course alterations, joint positions and crossing points with other services (active and retired). Such a position list should be provided with geodetic references and local datum shift parameters + +for example, from WGS-84 (World Geodetic System 84) for the main international geodetic system; + +- general layout map with the whole cable route and sections; +- detailed landing point map containing, at minimum, the following information: + - cable position after burial in the landing and shore approach area up to the beach joint; + - position of all the relevant structures at shore, if any, such as spare coils, concrete mooring blocks, signal poles; + - burial depth for all the above-mentioned structures; + - brief description and depth of the cable protections at sea in the different sections; + - any useful information to determine the position of the cable and any relevant structures for maintenance or new system installation purposes. + +# 4 Maintenance/Repair Log + +Such documentation should also be updated on the basis of a *Maintenance/Repair Log* with the following information: + +- operation number and date; +- name of the plant repaired or replaced; +- cable repair ship; +- details of repairs or replacement (cable type(s), quantity of original cable removed, quantity of spare cable installed, repair joint(s) locations and burial as applicable); +- position of failure (longitude, latitude and water depth). These coordinates have to be provided in the same geodetic references showed in the As-laid Report of the plant; +- as-laid map (i.e. for the deviation (e.g. "omega") or course alteration resulting on sea bed after replacement); +- measurements. + +The *As-laid Report* and the *Maintenance/Repair Log* should be required in the installation or repair supply contracts, as well as the delivery time, and should be provided after the completion of the works. + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure and Internet protocol aspects | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.3-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg b/marked/L/T-REC-L.3-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..64672153e39c851d9e16fdbc702e526c7ba7e8a7 --- /dev/null +++ b/marked/L/T-REC-L.3-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:454a9958ffe168868cb7d38a0eb24418dafe31a7a4245c992089b2316ac37d3e +size 7392 diff --git a/marked/L/T-REC-L.3-198811-I_PDF-E/raw.md b/marked/L/T-REC-L.3-198811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..c6f4430357a044ba5f89ffcd38ebe76303b2fe11 --- /dev/null +++ b/marked/L/T-REC-L.3-198811-I_PDF-E/raw.md @@ -0,0 +1,131 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a lightning bolt superimposed on it, and the letters 'ITU' in a bold, sans-serif font. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**L.3** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**CONSTRUCTION, INSTALLATION AND +PROTECTION OF CABLES AND OTHER ELEMENTS +OF OUTSIDE PLANTS** + +--- + +**ARMOURING OF CABLES** + +**ITU-T Recommendation L.3** + +(Extract from the *Blue Book*) + +--- + +# NOTES + +1 ITU-T Recommendation L.3 was published in Volume IX of the *Blue Book*. This file is an extract from the *Blue Book*. While the presentation and layout of the text might be slightly different from the *Blue Book* version, the contents of the file are identical to the *Blue Book* version and copyright conditions remain unchanged (see below). + +2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +# **ARMOURING OF CABLES** + +*(Mar del Plata, 1968; modified at Melbourne, 1988)* + +## **1 Type of armouring** + +1.1 The most common forms of armouring are: + +- a) *Tape armouring* – This consists of overlapping steel tape or tapes, applied in helical form with a short lay, over the cable sheath. +- b) *Wire armouring* – This is formed from round, flat or trapezoidal steel wires applied helically around the cable sheath with a relatively long lay. + +1.2 These two types of armouring are used in combination with other protective layers (jute, plastic) for constructional or mechanical reasons, or for protection against corrosion. + +## **2 Choice of armouring** + +In deciding whether or not to use armouring and in choosing between the various types of construction, very careful consideration should be given to the local conditions of installation, such as: + +- a) whether the cables are laid in duct or direct in the soil; +- b) whether the cables are laid in a trench alongside a road or on private land; +- c) what material is used for the cable sheath; +- d) whether other cables are or may be laid along the same run; +- e) the nature of the soil: rocky, sandy, corrosive or not; presence of micro-organisms; +- f) the depth of the trench, which in any case should not be less than 50 cm, and for large cables 80 cm; +- g) the risk of induction; +- h) the risk of attack by rodents or insects; +- i) the degree of exposure to lightning; +- j) whether the size and importance of the link justifies special precautions, in which case steel-wire armouring provides additional protection, particularly in manholes; +- k) whether a long draw-in is required, e.g. crossings under rivers (as cases of this are infrequent, no need is envisaged for a new design of land cable incorporating a central strain wire). + +## **3 Protection provided** + +With cables laid directly in the soil, armouring contributes to safe installation and reliability of operation by ensuring protection of the cables against: + +- a) mechanical damage caused by stones and excavation equipment or tools; +- b) rodents and insects; +- c) chemical or electrolytic corrosion; +- d) effects of atmospheric discharges; +- e) indication phenomena due to the proximity of power lines. + +## **4 Tape armouring** + +Tape armouring is to be preferred for protection against damage by pointed digging tools, sharp stones, etc. It is also useful for providing magnetic screening for circuits within the cable, for which wire armouring is much less effective, because the air gaps between the individual steel wires, which are arranged circumferentially around the cable, greatly reduce the magnetic coupling between the armoured sheath and the conductors within the cable. + +## **5 Wire armouring** + +Wire armouring gives considerable additional tensile strength to a cable and is useful where pulling-in stresses are high (long draw-in) or where high stresses arise from conditions of use, for example where there is ground subsidence in mining districts and where cables are run in water and bogs or in shafts leading to deep level locations. + +## **6 General type of armouring** + +For cables with a metallic sheath of lead or aluminium, the type of armouring in most common use consists of two helical windings of steel tape between layers of impregnated paper and jute with an external protection of jute yarn or other fibre. This type of armouring ensures good protection in all five cases listed in § 3 above. + +For plastic-sheathed cables, a light armouring may be used, formed of metallic tapes (steel, aluminium or copper) between two coverings of plastic material (polyethylene or PVC). Cables of this design are protected chiefly against the hazards mentioned in 3b) and 3c) above and to a certain extent against hazards 3a) and 3d) above. + +## **7 Armouring for main cables** + +The major cables in a long-distance network are certainly best protected by a watertight metallic sheath and the conventional armouring described above but the price of such protection is relatively high. + +The cost of cables can be reduced by using a thin welded-steel sheath protected against corrosion by a bituminous compound and a plastic covering. This protects the cable, though to a lesser degree, against hazards 3a), b), c), d) above; some protection against induction may be obtained by inserting conductor elements or copper or aluminium bonds under the steel sheath. + +## **8 Through-connection of armouring** + +In case long-distance cables or similar cables are provided with metal armouring, this should be through-connected electrically at the splicing points. This should be done to obtain maximum protection against the effects of atmospheric discharges and protection against induction. + +Metal armouring on cables forming part of the distribution network should also be through-connected in case such protection is needed. + +In case metal-armoured cables are also provided with a metal sheath, it may be desirable to through-connect the sheath and the armouring electrically at the splicing and/or repeater points. This should be done to neutralize any differences in potential between the armouring and metal sheath, and to obtain maximum protection against magnetic interference. Through-connection may create corrosion problems, which will usually reduce the lifetime of the metal armouring. + +## **9 Omission of armouring** + +On directly buried cables, metal armouring can be dispensed with in case the cable is provided with a strong plastic sheath, for example of polyethylene. A further prerequisite is that the soil and laying conditions should be favourable. + +Additional protection, for example of optical fibre cables, may be obtained by providing the cable sheath with an external layer of polyamide (thickness 0.4 - 0.5mm). This has a favourable effect as a wearing surface when drawing the cable over long distances. Moreover, the layer gives a certain degree of protection against light mechanical attacks. + +## **10 Corrosion considerations – cables with metal sheaths** + +Both tape and wire armouring are useful in mitigating corrosion attack; largely because they tend to keep the impregnated coverings lying beneath them in good order and so safeguard the metal sheath from the effects of differential aeration, etc. + +## **11 Rodents and insects** + +Damage from rodents and insects to direct buried cables may be high in some areas. In those locations, it may be advisable to consider the application of some type of armouring. For detailed information regarding armour protection against rodent and/or insect attack, the reader is directed to Part IV-B, Chapter II of the CCITT manual *Outside plant technologies for public networks*, mentioned in Recommendation L.1. + +## **12 Tropical countries** + +In tropical countries special attention must be paid to §§ 6 and 7 above and to the danger from micro-organisms. + +In general, it is safe to dispense with armouring only when: + +- cable is laid in duct; +- no magnetic screening is required, or where this is provided by some other metallic layer included for the purpose; +- when there is no risk of corrosion or where corrosion protection is provided by some other layer included for this purpose; +- in the case of directly buried cables, where the soil is homogeneous and contains no flints or rocks likely to damage the cable, and where there is no danger of damage by rodents and insects. + +However, special local conditions may still make armouring necessary, even 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TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.33** + +(10/98) + +SERIES L: CONSTRUCTION, INSTALLATION AND +PROTECTION OF CABLES AND OTHER ELEMENTS OF +OUTSIDE PLANT + +# --- **Periodic control of fire extinction devices in telecommunication buildings** + +ITU-T Recommendation L.33 + +(Previously CCITT Recommendation) + +--- + +## ITU-T L-SERIES RECOMMENDATIONS **CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT** + +![A large empty rectangular box with a double border, likely a placeholder for a diagram or image.](c803f6f6e2c49429d2951832bd0f208d_img.jpg) + +A large empty rectangular box with a double border, likely a placeholder for a diagram or image. + +*For further details, please refer to ITU-T List of Recommendations.* + +# **PERIODIC CONTROL OF FIRE EXTINGUITION DEVICES IN TELECOMMUNICATION BUILDINGS** + +## **Summary** + +This Recommendation considers the maintenance and control of fixed installations and portable extinguishers. It describes the procedures for inspection, maintenance and discharge testing of fixed water, CO2 and Halon 1301 installations, and portable extinguishers. + +## **Source** + +ITU-T Recommendation L.33 was prepared by ITU-T Study Group 6 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 9th of October 1998. + +## FOREWORD + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## INTELLECTUAL PROPERTY RIGHTS + +The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 1999 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +| | | Page | +|-------|--------------------------------------|-------------| +| 1 | Introduction ..... | 1 | +| 2 | It is recommended ..... | 1 | +| 2.1 | Portable extinguishers ..... | 1 | +| 2.1.1 | Inspection ..... | 1 | +| 2.1.2 | Maintenance ..... | 2 | +| 2.1.3 | Discharge tests ..... | 2 | +| 2.2 | Fixed installations ..... | 3 | +| 2.2.1 | Fixed water installations ..... | 3 | +| 2.2.2 | CO 2 installations ..... | 3 | +| 2.2.3 | Fixed Halon 1301 installations ..... | 4 | +| 2.3 | Maintenance periods..... | 4 | + + + +# **PERIODIC CONTROL OF FIRE EXTINGUITION DEVICES IN TELECOMMUNICATION BUILDINGS** + +*(Geneva, 1998)* + +# **1 Introduction** + +Once a fire extinction system has been designed and adopted, it becomes the responsibility of the telecommunication enterprise to ensure that it is properly controlled and maintained. + +Telecommunication buildings are equipped with two types of fire extinction systems: + +- portable extinguishers; +- fixed installations. + +One of the key factors in effective fire control, when a fire breaks out, is the proper upkeep and optimal performance of these systems. + +Good care and maintenance of fire extinction systems are vital to ensure that they operate properly in an emergency. Without adequate planning and implementation of maintenance programmes, even the best designed systems may fail at the critical moment. + +Also to be taken into account is the role played by insurance companies, which carry out periodic inspections of fire extinction systems and whose reports influence the cost of insurance premiums. + +## **2 It is recommended** + +Methods for the inspection and maintenance of every component of fire extinction systems should be introduced, with a view to guaranteeing their effectiveness in the event of a fire. + +Inspection of fire extinction installations should be carried out in compliance with internal policies adopted in that respect by the telecommunication enterprise. + +According to inspection schedules and standards, inspections may be carried out: + +- a) by the enterprise's own specially trained personnel; +- b) by specialized companies, which must comply with the requirements laid down by the competent authorities in each country. + +### **2.1 Portable extinguishers** + +Fire extinguishers should be subjected to inspection, maintenance and refilling procedures designed to ensure their optimal operation in the event of the outbreak of fire. The aim is to ensure that extinguishers are loaded and will operate effectively upon use. + +#### **2.1.1 Inspection** + +A general inspection should be made of the state of fire extinguishers, as well as their accessibility and markings. + +This inspection will verify that: + +- fire extinguishers are located as indicated in the corresponding plan; +- they are clearly visible; + +- access to them is not obstructed; +- they have not been activated, nor are partially or completely empty; +- they have not been handled improperly; +- their containers have not suffered obvious damage; +- service pressures are as required (pressure gauge readings); +- maintenance cycles are observed. + +#### **2.1.2 Maintenance** + +The maintenance procedure should consist in an exhaustive inspection of the three main parts of the fire extinguisher: + +- the mechanical part; +- the extinguishing agent; +- the propellant part. + +Fire extinguisher maintenance – particularly where hydrostatic testing and reloading is concerned – is a specialized task which must be carried out by trained personnel. Given the importance of this task and the need for reliability in an emergency, we recommend that Administrations contract companies which have proven experience in this activity, have adequate facilities and comply with the regulations in force in each country. + +All fire extinguishers should have an attached card showing the expiry dates of the hydrostatic test and extinguishing agent. + +In addition to the card, a permanent record, showing the following information, should be kept on file for each fire extinguisher: + +- a) date of maintenance and name of the person responsible; +- b) date of last reloading and name of the person responsible; +- c) permanent deformation following hydrostatic testing. + +The need to reload fire extinguishers may arise in the course of maintenance. + +Reloading consists in topping up or replacing the extinguishing agent and, if necessary, the propellant gas. For this operation, the directions given on the fire extinguisher specification plate must be followed, and only the agents indicated there may be used. + +After reloading, pressurized or auto-propelled fire extinguishers must be submitted to a test to check tightness and losses; this test must be accurate enough to ensure at least one year of extinguisher operability. + +Seals and instruction labels must then be replaced, as must the security pin which prevents accidental actuation of the extinguisher. + +#### **2.1.3 Discharge tests** + +Owing to possible deterioration, the extinguishing agent needs to be renewed. This procedure consists in discharging the extinguisher, carrying out hydrostatic testing of the container and checking the operation of each of the components. + +The frequency of inspections, maintenance and discharge tests should be set by each Administration according to locally prevailing conditions. + +### **2.2 Fixed installations** + +An inspection and maintenance programme should be established for all devices and equipment forming part of fixed fire extinction installations. + +#### **2.2.1 Fixed water installations** + +##### **2.2.1.1 Installed fire hydrants** + +Checks should be carried out to ensure that: + +- water supply sources are in good repair; +- inlet valves and fixed spigots remain open and secured; +- piping joins present no leaks; +- hoses and valve levers and taps are properly accessible; +- hose cabinets are in good repair; +- hoses are in perfect condition, by unrolling them to check for cuts, bad joins and loose connections; +- all hoses withstand pressures in accordance with national standards, without presenting leaks. + +##### **2.2.1.2 Hydrants** + +The operational condition of all piping, and correct positioning valves, hose nozzles and ancillary items should be checked. + +##### **2.2.1.3 Dry rising mains** + +The nozzles of dry rising mains and their supply intakes should be checked, ensuring that external caps and coupling stopcocks are shut, that connection caps are in good condition and that section stopcocks are open. + +##### **2.2.1.4 Sprinklers** + +Sprinkler systems should be inspected by the supplier company or other specialized company acknowledged by a recognized authority. + +It should be checked that sprinkler heads are unobstructed. The testing valve for each sector of the installation areas should be activated, and in each case the correct operation of the other components should be checked. + +Periodic testing programmes and reports should be scheduled according to the type and critical level of each component of the system. + +#### **2.2.2 CO2 installations** + +##### **2.2.2.1 Inspection** + +- The state of the CO2 in low and high pressure systems should be checked regularly, as well as immediately after the activation of such systems. +- The whole system should be inspected and all devices checked, with partial discharge if necessary. +- Inspectors should verify whether the risk level or condition of premises have changed. +- Cylinder weights should be checked and cylinders replaced or reloaded if losses are greater than 10%. + +##### **2.2.2.2 Tests and maintenance** + +- Operating tests should be carried out on all system components. + +#### **2.2.3 Fixed Halon 1301 installations** + +In view of the negative impact of Halon 1301 on the environment, it is strongly recommended that Halon 1301 or other CFC components be eliminated from all fire extinction devices. + +### **2.3 Maintenance periods** + +Maintenance periods for several national standards are given in Appendices I to IV of Recommendation L.23. + +## ITU-T RECOMMENDATIONS SERIES + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of the ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure | +| Series Z | Programming languages | \ No newline at end of file diff --git a/marked/L/T-REC-L.35-199810-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg b/marked/L/T-REC-L.35-199810-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..a7da83ecb82b51a4cef7694858eef2c35f1986ff --- /dev/null +++ b/marked/L/T-REC-L.35-199810-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:d77a478c5b78d330a2a6abbd32e7d0ac053d8b9c1ffe8a96476214afa6ddf7ae +size 8196 diff --git a/marked/L/T-REC-L.35-199810-I_PDF-E/c803f6f6e2c49429d2951832bd0f208d_img.jpg b/marked/L/T-REC-L.35-199810-I_PDF-E/c803f6f6e2c49429d2951832bd0f208d_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..c94de56063d6fcee275d62b625aeba437d03de40 --- /dev/null +++ b/marked/L/T-REC-L.35-199810-I_PDF-E/c803f6f6e2c49429d2951832bd0f208d_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:d43a3a4148c8763005c3ce7c62b5a581e6b08c2ad2952e635b891eb5edc14883 +size 10826 diff --git a/marked/L/T-REC-L.35-199810-I_PDF-E/raw.md b/marked/L/T-REC-L.35-199810-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..08843c3057ac61673405fa2af78b88b7a7696485 --- /dev/null +++ b/marked/L/T-REC-L.35-199810-I_PDF-E/raw.md @@ -0,0 +1,209 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features the letters 'ITU' in a bold, sans-serif font, superimposed on a stylized globe with intersecting lines. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.35** + +(10/98) + +SERIES L: CONSTRUCTION, INSTALLATION AND +PROTECTION OF CABLES AND OTHER ELEMENTS OF +OUTSIDE PLANT + +--- + +**Installation of optical fibre cables in the access +network** + +ITU-T Recommendation L.35 + +(Previously CCITT Recommendation) + +--- + +# ITU-T L-SERIES RECOMMENDATIONS **CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT** + +![A large empty rectangular box with a double border, likely a placeholder for a diagram or image.](c803f6f6e2c49429d2951832bd0f208d_img.jpg) + +A large empty rectangular box with a double border, likely a placeholder for a diagram or image. + +*For further details, please refer to ITU-T List of Recommendations.* + +# **ITU-T RECOMMENDATION L.35** + +# **INSTALLATION OF OPTICAL FIBRE CABLES IN THE ACCESS NETWORK** + +## **Summary** + +The Recommendation gives information about the methodologies recommended to install fibre optic cables in the access network. In particular, it gives guidance for installation in ducts, aerial installation and directly buried cables. Appendix I provides the experiences of nine countries on this matter. + +## **Source** + +ITU-T Recommendation L.35 was prepared by ITU-T Study Group 6 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 9th of October 1998. + +## FOREWORD + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## INTELLECTUAL PROPERTY RIGHTS + +The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 1998 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +# CONTENTS + +| | Page | +|--------------------------------------------------------------------------------------|-------------| +| Appendix I – International experience on access network installation procedures..... | 2 | +| I.1 General aspects..... | 2 | +| I.2 Duct installation ..... | 2 | +| I.3 Directly buried cables..... | 3 | +| I.4 Aerial installation ..... | 3 | + + + +## **Recommendation L.35** + +## **INSTALLATION OF OPTICAL FIBRE CABLES IN THE ACCESS NETWORK** + +*(Geneva, 1998)* + +## **Introduction** + +Optical fibres have been used for some time as transmission media in the access network. The different network architectures used are described in Annex A/L.15. + +The procedure for connecting customers to the public switched telephone network via optical fibre is described in Recommendation L.17. + +In addition, Chapter II (Cable installation) of the Manual on Optical Fibre Cables "Construction, installation, jointing and protection of optical fibre cables" provides general indications for the installation of any type of fibre; more detailed indications may, however, be necessary for the installation of optical fibre cables in the access network. + +### **Considering** + +- that the optical fibre access network is expanding rapidly; +- that the characteristics of the network are, in many cases, different from those of other types of network; +- that this type of network can be installed in different environments: rural, suburban and urban; +- that although installation in ducts is common, directly buried or aerial installations are also possible; +- that there are certain options in each type of installation that may prove advantageous, + +### **it is recommended** + +- 1) In general: + - that a study of economic factors, environmental impact and rules or regulations in each region should be conducted to decide on the type of installation: in ducts, directly buried or aerial; + - that existing infrastructure should be used wherever possible (ducts, poles, etc.); + - that installation should be undertaken by qualified staff who are skilled in the type of installation chosen. +- 2) If the installation is in ducts: + - that manholes or boxes should be used as network splice and flexibility points; + - that when the diameter of the duct permits and PE or PVC sub-ducts are used, then they should be installed within the duct typically by pulling; + - that cables should be installed in the duct by any of the methods described in Chapter II (Cable installation) of the Manual on Optical Fibre Cables; + - that when required, the cable should be installed from an intermediate point, laying part of the cable as a figure eight; + - that consideration be given to the storage of excess cable in boxes or manholes. + +- 3) If the cable is directly buried: + - that the splice cases should be directly buried or protected by a prefabricated box; + - that any of the traditional methods described in Chapter II (Cable installation) of the Manual on Optical Fibre Cables should be used. +- 4) If the installation is aerial: + - that poles should be made of wood, cement, steel, fibre or plastic depending on the results of the economic and environmental impact study; + - that either the cable should be lashed to or twisted around a support cable/wire or a self-supporting cable should be used; + - that the cable should be suspended on all poles, however at special positions, for example: + - splice poles; + - end of the route; + - river or road crossing; + - every given number of poles, + the cable should be anchored (fixed to the pole), in order to transfer the main load from the cable on to the pole; + - a length of cable for cable splicing purposes should be stored at splicing positions. + +# APPENDIX I + +## **International experience on access network installation procedures** + +The information in this appendix has been summarized from the replies from nine countries to a questionnaire sent to ITU-T Study Group 6 participants. + +The range of data shown incorporates the minimum and maximum values provided within the replies. + +### **I.1 General aspects** + +- I.1.1 Mean distance from exchange to customer: 300-5000 m +- I.1.2 Maximum distance from exchange to customer: 2-30 km +- I.1.3 Type of installation: Mainly in ducts + +### **I.2 Duct installation** + +- I.2.1 Number of manholes and boxes per km along the route: 1-30 +- I.2.2 Duct material: PVC, HDPE, PE, earthenware and steel +- I.2.3 Internal diameter of the duct bore: 27-125 mm +- I.2.4 Sub-duct material: PVC and PE +- I.2.5 Internal diameter of sub-ducts: 14-44 mm +- I.2.6 Maximum cable length between splices: 400-6000 m +- I.2.7 Excess length of cable stored in boxes (when applicable): 2-22 m + +### **I.3      Directly buried cables** + +**I.3.1**    Maximum length between splices: 2000-6000 m + +### **I.4      Aerial installation** + +**I.4.1**    Mean length between poles: 25-80 m + +**I.4.2**    Maximum length between poles: 50-200 m + +**I.4.3**    Profile of self-supporting cable (when applicable): Figure 8 and circular shape + +**I.4.4**    Excess cable length in splicing points: 0.8-10 m + + + +# ITU-T RECOMMENDATIONS SERIES + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of the ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | 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+--- + +**Use of trenchless techniques for the +construction of underground infrastructures for +telecommunication cable installation** + +ITU-T Recommendation L.38 + +(Previously CCITT Recommendation) + +--- + +# ITU-T L-SERIES RECOMMENDATIONS + +# **CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT** + +![](61972112770d9c8fb00883057954f885_img.jpg) + +*For further details, please refer to ITU-T List of Recommendations.* + +# **USE OF TRENCHLESS TECHNIQUES FOR THE CONSTRUCTION OF UNDERGROUND INFRASTRUCTURES FOR TELECOMMUNICATION CABLE INSTALLATION** + +## **Summary** + +This Recommendation describes the main techniques which allow installation of underground telecommunication network infrastructures minimizing or eliminating the need for excavation. These techniques, commonly known as trenchless or no-dig techniques, create a horizontal bore below the ground in which the underground infrastructure (ducts, pipes or direct buried cables) can be placed. + +Trenchless techniques can reduce environmental damage and social costs and at the same time, provide an economic alternative to open-trench methods of installation. + +After a description of the available techniques, this Recommendation examines the different kinds of work that are performed, the preliminary operation that shall be carried out, the drilling operation and the installation procedure advising on general requirements. + +## **Source** + +ITU-T Recommendation L.38 was prepared by ITU-T Study Group 6 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 24th of September 1999. + +## FOREWORD + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation the term *recognized operating agency (ROA)* includes any individual, company, corporation or governmental organization that operates a public correspondence service. The terms *Administration*, *ROA* and *public correspondence* are defined in the *Constitution of the ITU (Geneva, 1992)*. + +## INTELLECTUAL PROPERTY RIGHTS + +The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 1999 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +| | | Page | +|-------|--------------------------------------------------------------------------------|------| +| 1 | Scope..... | 1 | +| 2 | Available techniques..... | 1 | +| 3 | Kinds of work ..... | 1 | +| 3.1 | Long sections ..... | 1 | +| 3.2 | Crossings..... | 2 | +| 3.3 | Urban environment ..... | 2 | +| 4 | Site investigation..... | 2 | +| 5 | Preparatory steps ..... | 3 | +| 5.1 | Use of trenchless techniques not requiring the excavation of a launch pit..... | 3 | +| 5.2 | Use of trenchless techniques that require the excavation of a launch pit ..... | 4 | +| 5.2.1 | Impact moling..... | 4 | +| 5.2.2 | Pipe ramming..... | 4 | +| 5.2.3 | Microtunnelling and pipejacking..... | 4 | +| 6 | Drilling operations ..... | 5 | +| 6.1 | Guided boring/directional drilling ..... | 5 | +| 6.1.1 | Pilot bore creation..... | 5 | +| 6.1.2 | Reaming and pullback ..... | 6 | +| 6.1.3 | Duct inspection..... | 7 | +| 6.2 | Impact moling ..... | 7 | +| 6.3 | Pipe ramming..... | 8 | +| 6.4 | Pipejacking and microtunnelling ..... | 8 | +| 7 | Record keeping and documentation..... | 9 | +| 8 | Ground conditions..... | 9 | +| 8.1 | Guided boring/directional drilling ..... | 9 | +| 8.2 | Impact moling ..... | 10 | +| 8.3 | Pipe ramming..... | 10 | +| 8.4 | Pipejacking and microtunnelling ..... | 11 | +| 9 | Applications ..... | 12 | +| 9.1 | Guided boring/directional drilling ..... | 12 | +| 9.2 | Impact moling ..... | 13 | +| 9.3 | Pipe ramming..... | 13 | +| 9.4 | Pipejacking and microtunnelling ..... | 13 | + +| | Page | +|------------------------------------------------------------|-------------| +| 10 Conclusion ..... | 13 | +| 11 Glossary ..... | 14 | +| Appendix I – Available techniques ..... | 14 | +| I.1 Guided boring and directional drilling..... | 14 | +| I.1.1 Methods ..... | 15 | +| I.1.2 Drilling machines ..... | 16 | +| I.1.3 Drill pipes ..... | 18 | +| I.1.4 Drilling fluids ..... | 18 | +| I.1.5 Tracking and guidance systems ..... | 19 | +| I.1.6 Ancillary equipment ..... | 20 | +| I.2 Impact moling ..... | 20 | +| I.2.1 Monitoring..... | 21 | +| I.2.2 Head types ..... | 22 | +| I.3 Pipe ramming..... | 22 | +| I.3.1 Set-up..... | 22 | +| I.3.2 Bore options..... | 23 | +| I.4 Pipejacking and microtunnelling ..... | 23 | +| I.4.1 Planning..... | 24 | +| I.4.2 Excavation and spoil removal in pipejacking..... | 25 | +| I.4.3 Excavation and spoil removal in microtunnelling..... | 25 | +| I.4.4 Microtunnelling work method classification..... | 29 | +| I.4.5 Position detecting methods..... | 30 | +| I.4.6 Soil improvement methods..... | 31 | +| I.4.7 Jacking frames ..... | 32 | +| I.4.8 Shafts ..... | 32 | +| I.4.9 Pipes..... | 32 | +| I.4.10 Lubrication..... | 33 | +| I.4.11 Interjacks..... | 34 | +| I.4.12 Jacking loads..... | 34 | + +# Recommendation L.38 + +# USE OF TRENCHLESS TECHNIQUES FOR THE CONSTRUCTION OF UNDERGROUND INFRASTRUCTURES FOR TELECOMMUNICATION CABLE INSTALLATION + +(Geneva, 1999) + +## 1 Scope + +This Recommendation: + +- makes a classification of different kind of works that are performed; +- describes the preliminary operations; +- describes the drilling operation and installation procedures requirements; +- describes situations where trenchless techniques are recommended. + +## 2 Available techniques + +A broad classification of the available trenchless techniques is given in Table 1. A more detailed description of each technique is reported in Appendix I. + +**Table 1/L.38 – Classification of trenchless techniques** + +| | | | | | +|------------------------------------|----------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--|--| +| Guided boring/directional drilling |
  • • Fluid-assisted boring
  • • Dry boring
| | | | +| Impact moling | | | | | +| Pipe ramming | | | | | +| Pipejacking | | | | | +| Microtunnelling |
  • • High strength pipe method
|
  • * Penetrating method
  • * Auger excavation method
  • * Slurry method
  • * Slurry pressure balanced method
  • * Boring method
| | | +| |
  • • Low strength pipe method
|
  • * Penetrating method
  • * Auger excavation method
  • * Slurry method
  • * Slurry pressure balanced method
  • * Boring method
| | | + +## 3 Kinds of work + +The following work classification is performed in order to give advice on the best equipment to use, depending on the different operational needs. + +### 3.1 Long sections + +Trenchless techniques can be used to install underground ducts along the roads as an alternative to traditional digging techniques. Long installation lengths can be achieved (several km) by dividing the work length into shorter sections (100-200 m as an average). The length of each section will depend on the characteristics of the machines and the design requirements. + +*It is recommended:* + +that guided boring/directional drilling (both fluid-assisted and dry boring) machines be used for this particular application. + +### **3.2 Crossings** + +River and railway crossings were the first applications of no-dig technology due to the fact that traditional digging techniques were not suitable. Surface-launched machines are often the best solution because obstacles can be crossed with a curved drilling path, thus avoiding the need to excavate deep launch and reception pits (especially in river crossings). It is possible to consider two different kinds of crossing with respect to the length and to the depth of the installed duct. + +- Road and railway crossings: the length of the drilling is normally not very long. For these situations + +*it is recommended:* + +that both fluid-assisted and dry directional drilling machines be used or the use of microtunnelling systems depending on the duct diameter. + +- River crossings: the length and the depth of the bore normally required are very long and deep and it is important to avoid the excavation of big launch and reception pits on the opposite sides of the river. For these situations: + +*it is recommended:* + +that the drilling is started directly from the surface using a fluid-assisted directional drilling system. + +### **3.3 Urban environment** + +This represents one of the most attractive applications of no-dig technology because it could avoid or drastically reduce the troublesome drawbacks normally created by digging work in urban areas. Due to the small diameters of the ducts and the short distance of each drilling section (manholes or chambers are normally very close together), + +*it is recommended:* + +that a small and dry directional rig is used, in order to reduce the overall dimension of the working site, and to avoid flooding of the drilling fluid along the drilling path and the use of microtunnelling systems, depending on the duct diameter. + +## **4 Site investigation** + +Exhaustive knowledge of the work site and of the subsoil, right from the first design phases is essential, both to reduce the number of failures and/or to limit possible damage to pre-existing services or structures and to minimize horizontal digging costs by use of the various no-dig techniques. + +*It is therefore recommended that:* + +- The drilling plan shall be accompanied by a series of information of the following kind: + - statutory/administrative; + - technological (e.g. presence of utilities or obstacles); + - geolithological, hydrogeological and geotechnical. + +Most of this information can be acquired by consulting pre-existing documentation of work carried out in the area (e.g. laying of utilities, etc.). + +- Maximum care shall be paid to public utilities which are potentially dangerous (e.g. gas mains) or of public importance (e.g. hospital telephone lines). Further essential information on important or potentially dangerous circumstances may sometimes be obtained from the contracting company which executed the work. +- The following information on the services or structures is also necessary: + - materials (PVC, metal); + - diameter, single or multiple; + - planned and/or real depth of emplacement; + - infill materials (rubble, sand). +- It is sometimes necessary, when working with documentation made available by local authorities or other companies, to distinguish between "planning" and "as installed" drawings. + +Due to these reasons, in order to get precise information on the location of existing buried utilities, *it is recommended that:* + +a direct on-site investigation should definitely be performed using appropriate equipment. + +Pipe and cable locators can detect metallic pipes, current carrying electrical cables and telecommunications cables. Ground Penetrating Radar systems give greater information often detecting non-metallic pipes, cables, zones of leakage and sub-surface discontinuities such as road construction layers or rock strata. + +Complete information about soil conditions can be obtained by conventional trial-holes and borings. + +## 5 Preparatory steps + +### 5.1 Use of trenchless techniques not requiring the excavation of a launch pit + +For trenchless techniques not requiring the excavation of launch and reception pits, *it is recommended that:* + +- before starting the work it is necessary to make an accurate evaluation of the available space close to the starting point, taking into account the dimension of the equipment to be used; +- when drilling fluids are used, the overall dimension of the truck carrying the pump and the tanks which are connected to the drilling machine shall be taken into account; +- when positioning the machine, it is necessary to consider the angle of incidence of the first rod with respect to the ground. This angle should not exceed 20° and consequently the drilling machine has to be placed at a suitable distance far from the starting point; +- if drilling fluids are used it is necessary to dig a small pit around the starting point to recover the mud produced by the drilling operations; +- in order to be able to monitor the pilot-bore position from the surface during the drilling operations, the drilling head should be equipped with sensors for measuring the following parameters: + - depth; + - inclination; + - orientation; + - temperature. + +- when using the walk-over system (see Appendix I), it is necessary to calibrate the gain of the receiver, according to the manufacturer's instructions, before starting the drilling of the pilot bore; +- it is also advisable to mark the drill pipes in line with a definite position of the drilling head (e.g. with the angled face up). This will enable the operator to judge the actual orientation of the drilling head during the boring of the pilot hole. + +### 5.2 Use of trenchless techniques that require the excavation of a launch pit + +#### 5.2.1 Impact moling + +When using the impact moling technique, once the desired route has been established, and before starting the creation of the bore, + +*the following operations are recommended:* + +- a launch pit and a reception pit are first excavated at the ends of the bore path, that are a little deeper than the planned depth of installation; +- the launch cradle, if used, is then set up; alternatively the mole can be positioned directly on the floor of the launch pit; +- using a ranging rod in the reception pit and a sighting telescope in the launch pit, the initial line of the bore is established by physically aiming the mole towards the ranging rod target; +- the mole is launched and allowed to advance a short distance. The line is checked for a final time before the whole body of the mole enters the ground. If the line is not correct, the bore is restarted. + +#### 5.2.2 Pipe ramming + +When pipe ramming systems are used, *the following preliminary operations are recommended:* + +- a typical ramming operation requires the establishment of a solid base, normally a concrete mat, on the launch side of the installation. This mat will usually be positioned in a starting pit or alternatively against the side of a slope; +- guide rails set to the line of the bore should then be installed on the mat; +- after positioning the first length of steel pipe on the guide rails, a cutting edge has to be formed or fitted to the lead end of the pipe, and the ramming hammer is attached to the rear of the pipe; +- depending on the diameter, inserts may have to be used to ensure solid and uniform contact between the hammer and the pipe. + +#### 5.2.3 Microtunnelling and pipejacking + +As far as microtunnelling and pipejacking projects are concerned, particular care shall be taken in preparing the launch or drive shaft. + +Drive shaft requirements vary greatly depending on the machine being used, ground conditions, pipe length and material, length of drive and type of installation. They may be round, rectangular or oval; sheet piled, segmentally lined, of special construction or even unsupported if ground conditions are good enough and local safety rules permit; one factor common to each drive shaft is that there has to be some form of reaction face for the jacking frame to push against. + +In suitable ground the reaction surface can simply be the back wall of the shaft, but this is usually not the case, and a thrust wall has to be provided. Normally of concrete construction, the thrust wall is an integral part of the shaft support and may be designed to allow the jacking frame to be rotated for a second bore in the opposite direction, or to allow a machine boring from another location to enter the shaft as a reception point. + +*It is therefore recommended that:* + +- the thrust wall shall enable the jacking frame to exert its maximum pushing force, whilst maintaining the integrity of the shaft structure and that of the surrounding ground, so as not to compromise the final pipeline structure; +- the shaft shall be constructed to be watertight, particularly in deep and difficult soil conditions, to minimize disturbance of the soil outside the shaft. A watertight shaft also minimizes uncontrolled drainage and dewatering of the zone around the shaft; +- the floor of the shaft needs to be set at the correct grade and be structurally strong enough to support all the microtunnelling equipment. The floor shall be structurally isolated from the shaft thrust wall; +- the thrust wall shall be constructed perpendicular to the direction that the pipe is to be installed and of sufficient structural capacity to transfer the jacking loads through the shaft wall and into the soil; +- even when the exit point of the shield is directly out of the ground at a set position, a reception arrangement shall be designed in order to prevent environmental contamination by loss of lubricant or slurry, or to prevent the ingress of water into the pipeline. + +## **6 Drilling operations** + +### **6.1 Guided boring/directional drilling** + +The work may be divided into different phases, listed in the following paragraphs. + +#### **6.1.1 Pilot bore creation** + +*It is recommended that:* + +- the location of the starting and arrival points shall be planned as a function of the drilling machine performances, in order to optimize the total number of drilling sections; +- in the case of crossings, when the new duct shall be connected with an existing infrastructure, the position of the starting and arrival points shall be determined as a function of the position of the existing manholes or chambers, taking into account the allowable bending radius of the drilling pipes and the duct to be installed; +- in the case of work in an urban environment, the drilling shall be performed behind the sidewalks, to limit possible drawbacks to traffic whenever possible; +- in the case of work in an urban environment, the use of drilling fluids, which could leak into the basement of adjacent buildings, shall be strictly avoided; +- when using the walk-over system, an operator shall follow the pilot bore progress from the surface, by means of the locator, once the drilling has started; +- when the planned depth is reached, the bore shall be performed following a horizontal line parallel to the ground surface. During this step it is advisable to read the data on the receiver at least every 5 metres and to mark the ground in line with the detected position of the drilling head so that the final position of the installed duct will be immediately shown (e.g. for updating a utility map of the area); +- when the walk-over system is used in combination with mud motors equipment, it is necessary to consider that, due to the position of the sonde relative to the drilling head, the data detection can only take place at 1 or 2 metres from the head, requiring the operator to anticipate the direction to take; + +- if a remote control unit for the drilling machine is not present, the operator who follows the pilot bore progress (locator) shall communicate the progress to the machine operator (driller), who needs this information in order to control the drilling direction; +- in the case of particular crossings (such as rivers and highways), it is not always possible to follow the progress of the drilling head by means of a locator from the surface. Even if a hard-wire tracking system is used it is advisable to use all the other available data, such as the length of the drill pipes and the last parameters measured by the sensors inside the drilling head (depth, inclination and rotation), to determine the drilling path; +- approaching the arrival pit, the drilling head shall be raised up gradually to reach the final point with an inclination similar to the starting one (max. 20 degrees); +- once the drilling head surfaces at the exit point, a measurement shall be made to determine if the actual exit is within the allowable tolerances. If a portion of the bore is out of the given tolerance, the drill string shall be pulled back and this segment of the bore can be re-drilled. + +#### 6.1.2 Reaming and pullback + +In certain installations, the pipe can be pulled straight into the pilot hole after it is completed. However, in most installations, the bore will require reaming to enlarge the hole to accommodate the product pipes. In this case, + +*it is recommended that:* + +- when the pilot bore is completed, the drilling head is substituted with a reamer which is pulled back inside the bore to enlarge its diameter. To allow correct installation, the internal diameter of the bore shall exceed the maximum external diameter of the duct (or of the bundle of ducts) by at least the 20%. This is necessary to allow for an annular void for the return of drilling fluids and spoils and to allow for the bend radius of the product pipes; +- sometimes more than one reaming operation is required to perform a sufficiently large bore. In this case, a second drill string shall be connected to the reamer using a swivel joint. The rods are pulled inside the bore, so that when the reaming operation is completed they can be used immediately to pull back another reamer; +- when the required bore diameter is obtained, the drill pipe shall be connected to the product pipes using a pullhead or pulling eye and a swivel. A reamer shall also be placed between the pullhead and the drill string to ensure that the hole remains open and to allow more lubricating fluid to be pumped into the hole during the pullback; +- during the pullback phase, it is necessary that the ends of the duct/s are sealed to avoid the ingress of mud and dirt; +- if a single bore is not sufficient to house the ducts that shall be installed, a second bore shall be performed. In this case, it is necessary to maintain a certain distance between the first and the second bore in order not to damage the installed duct/s. This distance depends mainly on the diameter of the ducts but it is advisable to maintain a distance of at least 1 metre between the two bores; +- if the duct terminations are directly buried, they shall be signalled with surface or buried markers; +- the termination of all the installed ducts shall be sealed in order to avoid the ingress of mud and dirt; +- depending on the diameter, the pipes that have to be installed are supplied wound on reels or in shorter straight sections. In the second case, in order to pull the pipes inside the bore, it is necessary to joint the different sections before starting the pulling phase and to avoid changes in the external pipe diameter, which could create problems during the pulling phase; + +- if two pipe sections are to be jointed inside a pit or a manhole, it is advisable to use mechanical couplers (e.g. plastic or brass couplers), where available. Mechanical couplers allow an hermetic seal which is necessary when using air or water for the subsequent installation of the cables; +- as far as metallic pipes are concerned, the jointing procedures shall follow the recommendations given by ISO 6761 Standard. + +#### 6.1.3 Duct inspection + +At the end of the installation, + +*it is recommended that:* + +the internal diameter be checked, over the whole length of the ducts, in order to be sure that no restriction or obstruction inside the ducts occurred during the pulling phase. + +It is possible to simply perform this operation by blowing inside the pipe a light circular probe having a diameter slightly less than the internal diameter of the pipe itself, which will reach the other end of the pipe if no restrictions or obstructions are present. As an alternative, a more precise inspection can be performed using CCTV (Close Circuit Television) system with semi-rigid cable which allows the camera to be pushed up to the pipe from a single access point. + +### 6.2 Impact moling + +After determining the initial line of the bore, the mole is launched and allowed to advance a short distance. In order to avoid misalignment with respect to the planned line, + +*it is recommended:* + +- that the line be checked for a final time before the whole body of the mole enters the ground; +- that the bore be re-started if the line is not correct; +- using, where possible, radio sondes which can be fitted either to the rear of the impact mole or, in some cases, within the front end. Although rear-mounted sondes give an indication of progress, they provide less useful information than front-mounted units. Depending on the mole size and length, the sonde can be some distance from the penetrating end of the tool and therefore responds much later than a front-mounted sonde to changes in direction and pitch and so give the operator less time to halt the bore and assess the next move. However, nose-mounted sondes have to be far more robust and well protected as they shall withstand the shock of the forces applied to the front of the unit by the hammer action. + +If an impact mole is forced off-line, or prevented from advancing by an obstacle, it is often easier to dig down to the unit, remove the obstruction, realign the mole and relaunch it, rather than to start the bore again. This is often aided by the reversing facility that most impact moles now have, which enables the unit to be backed away from an obstruction to a point where it was on the correct line and level. After removing the obstacle and backfilling the hole, the mole is restarted on the intended course. + +Moreover, particular attention shall be paid to the installation depth, to minimize or avoid surface damage due to soil compression restrictions. + +*It is therefore recommended:* + +that the bore be performed at least one metre deep for every 100 mm diameter of the tool. + +As most utility mains and services (except sewers) are laid at depths of less than two metres in most countries, this gives an effective upper limit of 200 mm for impact mole diameters. + +### 6.3 Pipe ramming + +To perform the correct use of pipe ramming systems, + +*it is recommended that:* + +- as there is usually no means of monitoring the direction of the pipe during operation, it is vital to establish a clear bore path prior to work commencing; +- when using an open-ended system (see Appendix I), the cylinder of ground within the circumference of the cutting edge stays inside the pipe during the bore. Over the short distances normally undertaken with pipe ramming, this accumulation of spoil is not usually a problem. However, for long bores, it should be remembered that the spoil adds to the weight of the pipe string being rammed and will therefore affect advance rates. In some instances it may be advisable to clean out spoil from the pipe during pipe string extension works, to limit the extra burden on the ramming hammer. Depending on diameter, this can be done either manually or by means of a scraper; +- if intermediate cleaning is not required, and the spoil remains in the pipe for the whole bore, it is necessary to remove it at the end of the installation. If pressurized water or compressed air is used on arrival of the pipe at the reception pit, the open end of the pipe shall be sealed with a suitable plug. + +### 6.4 Pipejacking and microtunnelling + +Referring to Appendix I for the detailed description of the techniques, + +*it is recommended that:* + +the following points be taken into consideration before starting the work: + +- the deflection at the pipe joint face shall not exceed $0.5^\circ$ although deflections of over $1.0^\circ$ may be permissible for curved drives using appropriate cushioning materials at pipe joints; +- particular care shall be taken by the operator in maintaining as straight a drive as possible to take full advantage of the design loading of the pipe. High deflection will reduce the maximum loading that the pipe string can withstand without fear of pipe failure in the ground; +- the joints between pipes shall not extend outside the barrel of the pipe. In other words, the entire joint shall be contained within the normal pipe external diameter; +- a correct use of lubrication materials and techniques shall be performed to bring a considerable reduction in jacking loads and ground support problems. It may also allow the use of smaller jacking frame, thus minimizing the size of the drive shaft and helping to reduce the overall cost of the project; +- lubricant shall be injected immediately into the annulus created by the tunnelling machine and on a continuous basis throughout the microtunnelling process; +- it is advisable to consult mud experts, prior to start of the microtunnel, to recommend the most suitable lubricants and procedures related to soil and groundwater conditions; +- soil conditions can affect the types and quantities of lubricants that are needed to maintain low friction, therefore it is necessary to be aware of changing soil conditions along the pipe route; +- where the lubrication of a pipe may not be sufficient in itself to allow successful completion of the jacking operation (for example, where the length of the pipe string is such that its resistance to movement will exceed the capacity of a practical sized jacking frame, or where friction forces or ground movement factors will be difficult to overcome), the "interjack" station option should be considered before reducing the planned length of the work (see Appendix I); + +- selection of the proper overcut (the difference between the excavated diameter of the bore and the outer diameter of the shield or pipe), is critical for completion of microtunnelling drives without unreasonably high jacking force or risk of settling the surface. Typical overcut values can vary from 0.7 cm to 3.7 cm on the radius, depending on the diameter of the machine, the depth below the surface and the ground conditions. Even in this case it is advisable to consult soil experts, together with equipment manufacturers, to determine the correct overcut for a given soil condition; +- dewatering the soil that the microtunnelling machine progresses through can have a dramatic effect on overall jacking forces. Dewatering is often necessary for shaft construction and sometimes for achieving exit of the shield from the soil into the shaft. However, dewatering beyond this point has a detrimental effect on the microtunnelling process. It can often cause substantial changes to the soil matrix and it is usually an unnecessary and expensive process in microtunnelling. It is therefore advisable to use dewatering only to prepare the site for microtunnelling and not during the progress of the machine; +- gradual steering of the microtunnelling system during the drive is vital to keep the jacking loads as low as possible. The operator shall continuously monitor the shield's position relative to the required line and grade and use small amounts of steering to keep the microtunnelling shield on line. Sudden steering corrections are not necessary with a correct survey and should be avoided; +- because of the tendency to make immediate and severe steering to correct the position, it is crucial that the machine is launched on the proper line to avoid excessive steering during the first part of the drive. + +## 7 Record keeping and documentation + +As utility corridors and existing crossings become more congested with new installations, it is increasingly important to maintain accurate documentation for future reference. + +*It is therefore recommended that:* + +drilling logs, or reports, be produced containing: + +- position of the installed pipes; +- specific data; +- times and locations; +- soil conditions; +- drilling data such as depth, angle and rate of penetration and utility crossings. + +## 8 Ground conditions + +### 8.1 Guided boring/directional drilling + +The capabilities of guided boring machines can vary considerably according to the type of ground through which they are drilling. In general, homogeneous clays are the most favourable soils. Sand can present problems especially if it is below the water table or is not self-supporting. Gravel can be penetrated at the expense of accelerated wear to the bore-head. In the case of gravel, it is essential to use mud as it holds the tunnel walls. + +To choose a suitable technique for the type of ground, the following advice and the classification given in Table 2 should be taken into account: + +- standard machines without percussive action or mud motors are generally unsuitable for penetrating rock or hard inclusions; + +- mud motors powered by the drilling fluid, double tube and head casing systems, can be used to drive rock cutting heads; +- a way of improving performance in hard ground is by the use of percussive action in conjunction with forward thrust and rotation; +- percussion allows improved penetration and directional control in stony soils or weak rock, but is not intended for drilling through solid rock or large masses or very hard material such as concrete; +- dry boring machines which use a combination of percussion and thrust and rotation actions, with water mist lubrication, enable the penetration of hard rock formations; +- fluid-assisted boring has greater versatility in terms of ground conditions and the maximum diameters can be achieved. However, it requires more equipment and involves dealing with mud-filled excavations and the disposal or recycling of materials; +- dry boring is essentially a displacement technique. As such, it is best suited to compressible, self-supporting soils and may not be appropriate for sands and gravels at bore diameters above about 75 mm. The risk of surface damage shall also be considered, especially in granular soils. + +Table 2 gives a general classification of suitable directional drilling systems with respect to different types of ground (see also Appendix I). + +**Table 2/L.38 – General classification of guided boring/directional drilling techniques (see Appendix I) with respect to the type of terrain** + +| Type of ground | Drilling technique | +|----------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------| +| Silt, clay, sand | Low pressure jetting
Dry boring | +| Gravel, marl, spoil, shale, clays | High pressure jetting
Dry boring
Double tube/head casing systems
Mud motors | +| Marl, spoil, clays, limestone, sandstone | High pressure jetting
Double tube/ head casing systems
Dry boring (percussion and water mist lubrication)
Mud motors | +| Limestone, sandstone, some granites, spoil, gneiss | Mud motors with tungsten carbide or diamond inserts
Dry boring (percussion/rotation and water mist lubrication) | + +### 8.2 Impact moling + +The compacting action of the impact mole means that, in general, the use of this technique is recommended only in soils that can be compressed or displaced. + +### 8.3 Pipe ramming + +Depending on the nature of the ground, ramming can be carried out with either an open or closed-ended pipe. Open-ended ramming is generally preferable. This has several advantages, including lower reaction against the ramming force, since only the cutting edge is pushed into the ground. + +*Therefore it is recommended that:* + +- open-ended ramming be used in hard ground, since, due to the small surface of the cutting edge, the soil does not have to be compressible; + +- closed-end ramming be used, in case of non-self-supporting ground, because the soil is displaced around the pipe and compacted around the wall of the bore. + +### **8.4 Pipejacking and microtunnelling** + +Modern technology has, in recent years, enabled both methods to be applied to a wide range of ground conditions, e.g. waterlogged sands and gravels, soft, stiff, dry or waterlogged clays, mudstones and solid rock. + +A classification of the microtunnelling driving methods can be made as a function of their performances in different ground conditions (see Table 3). + +*In addition, it is recommended that the following points be taken into account:* + +- the penetrating or press-in method should be used only in soil that can be compressed; +- the auger excavation method can be applied to a wide range of soil quality by selecting the appropriate excavation head. However, the driving machine has an open tip, making it unsuitable for crumbly soil; +- the slurry method can be applied to a wide range of soil qualities from crumbly and extremely soft soils to gravelly soils; +- the slurry pressure balanced method has the widest range of applicability. It can even be applied to ground containing gravel and cobble by mounting disc cutters or a cone-shaped crushing head; +- the boring method, by using an ultra-hard bit mounted onto the tip of the inner pipe, can be applied to very hard soil. + +**Table 3/L.38 – Fields of application of different microtunnelling excavation techniques as a function of driving distance, tunnel diameter and soil conditions** + +![A chart showing the fields of application for different microtunnelling excavation techniques based on driving distance, tunnel diameter, and soil conditions. The vertical axis represents driving distance from 50m to 250m. The horizontal axis represents tunnel diameter from 300mm to 700mm. The chart is divided into regions for 'Boring Type', 'Excavation and Slurry Discharge Type', 'Press-in Type', and 'Excavation with Auger Type'. Soil conditions are indicated by N-values: Rock (<10), Gravelly Soil (10-30), Hard Soil (30-100), and Normal Soil (>100).](8ccbc9fa77bf60ba0ca0b79dec8681b8_img.jpg) + +| Driving Distance [m] | soil condition (N-value) | | | | Diameter [mm] | +|----------------------|--------------------------|--------------------------------------|---------------|-------------|------------------------------------------| +| | Rock | Gravelly Soil | Hard Soil | Normal Soil | | +| 250 | | | | | | +| 200 | | | | | | +| 150 | | Excavation and Slurry Discharge Type | Press-in Type | | Press-in Type | +| 100 | | Excavation and Slurry Discharge Type | Press-in Type | | Excavation and Slurry Discharge Type | +| 50 | Boring Type | Excavation with Auger Type | | | Excavation with Auger Type Boring Type | + +A chart showing the fields of application for different microtunnelling excavation techniques based on driving distance, tunnel diameter, and soil conditions. The vertical axis represents driving distance from 50m to 250m. The horizontal axis represents tunnel diameter from 300mm to 700mm. The chart is divided into regions for 'Boring Type', 'Excavation and Slurry Discharge Type', 'Press-in Type', and 'Excavation with Auger Type'. Soil conditions are indicated by N-values: Rock (<10), Gravelly Soil (10-30), Hard Soil (30-100), and Normal Soil (>100). + +T0604310-98 + +## 9 Applications + +### 9.1 Guided boring/directional drilling + +A typical mid-range, surface-launched guided boring machine has a thrust and pullback capability of between 8000 and 15 000 kg and torque of up to 5000 Nm depending on its rotational speed. Such a machine would, depending on ground conditions, generally be capable of installing pipe of approximately 250-500 mm diameter over distances of between 100 and 350 metres. + +The largest directional drilling rigs can have a thrust of over 100 000 kg and are used primarily for long or large diameter crossings under rivers, estuaries, major highways and long sections. At the other end of the scale, compact rigs, for use in restricted spaces, with a thrust and pullback of around 4000 kg, can install pipes up to about 160 mm over distances of up 100 metres. This again depends on ground conditions. Some include the facility to reduce the track spacing for passage through narrow openings. + +Dry directional drilling systems, using a cone shaped reamer with tungsten-carbide cutting teeth connected directly to the drilling rods, can perform the installation of a small diameter pipes, ducts or cables (up to about 65 mm diameter). + +Dry installation of pipe diameters up to 250 mm require a pneumatically powered reaming hammer on the drilling head. + +### 9.2 Impact moling + +Because impact moling is generally unsteered, the technique is most suitable for short bores (up to 50 metres). A straight bore can often be maintained more easily at large diameters. Diameters range from about 45 to 200 mm depending on the pipe or cable being installed. + +### 9.3 Pipe ramming + +Pipe ramming is most often used to install new pipelines or casings into which new utilities will be installed. Installation distances are usually quite short – about 50 metres – on average. Steel pipe is used for the casing, as no other material is strong enough to withstand the impact forces generated by the hammer. The technique is often favoured for crossing under railways, road and waterways. Once the steel pipe is installed, it can be used as a pipeline in its own right, or as ducting for most types of pipe or cable. + +Bores up to 2000 mm diameter can be installed in suitable ground conditions, using impact ramming hammers of up to 600 mm diameters generating the equivalent of over 2 000 000 kg of ramming force. + +### 9.4 Pipejacking and microtunnelling + +Both pipejacking and microtunnelling are well suited to situations where a pipeline has to conform to a rigid line and level criteria. The guidance and control systems allow accurate installation within close limits of the target. + +Most microtunnelling drives are straight between shafts, although specialized systems are available for curved drives. Where, because of the curvature of the tunnel, line-of-sight is not possible between the drive shaft and the microtunnelling machine, specific alignment systems (e.g. gyroscopic devices, combination of electromagnetic induction and liquid pressure difference) may be used as an alternative to the usual laser equipment. + +The ranges of recommended applicability are given in Table 3. + +## 10 Conclusion + +Considering all the information given in this Recommendation and Appendix I, + +*it is recommended that trenchless techniques be used in the following situations:* + +- where road surface excavation is restricted or prohibited by administrative agencies, etc. (newly constructed roads, emergency vehicle entrances/exits, etc.); +- where the open-cut method cannot assure safety or would cause risks to traffic and pedestrians; +- where noise, vibration, dust and other pollution are caused by open-cut method; +- where the open-cut method may impede road traffic and thus hinder the business of nearby stores; +- where congested sections where open-cut method may damage the buried facilities of other companies or sections where the presence of buried objects causes significant lack of work efficiency; +- where conduits should be buried at deep locations and open-cut construction would greatly increase the amount of excavated soil; +- where road surfaces use high-grade material which would increase the cost of reinstatement after excavation; + +- where road sections with high traffic volumes where work is limited to the night-time hours (lower work efficiency, higher labour costs); +- where open-cut construction would involve extra costs to move historic remains or other items. + +## 11 Glossary + +**11.1 auger excavation method:** Excavation system using a screw conveyor inside the driving machine to remove the spoils. + +**11.2 hard-wire tracking system:** Monitoring system which requires a direct wire-link between the sonde and the receiver. + +**11.3 interjack station:** Ring of hydraulic jacks within a steel framework which is inserted into the pipe string at a strategic point in order to reduce the jacking force on the pipes. + +**11.4 mole:** Machine which bores into the ground. + +**11.5 mud motor:** An hydraulic motor driven by a high pressure mud flow placed into the drilling head. + +**11.6 N-value:** Number of blows necessary for a penetrometer to drive 30.5 cm into the ground by dropping a standard weight from a height of 76 cm (ASTM Standard Penetration Test). + +**11.7 open-cut method:** Construction method which implies the excavation of an open trench. + +**11.8 swivel joint:** Mechanical joint which avoids the transmission of rotational forces. + +**11.9 walk-over system:** Monitoring system which implies that an operator follows the drilling progress from the surface by means of a remote receiver. + +# APPENDIX I + +## Available techniques + +### I.1 Guided boring and directional drilling + +Guided boring and directional drilling techniques are used for the trenchless installation of new pipelines, ducts and cables. The drill path may be straight or gradually curved and the direction of the drilling head can be adjusted at any stage during the bore to steer around obstacles or under highway, rivers or railways. Drilling can be carried out between pre-excavated launch and reception pits, or from the surface by setting the machine to drill into the ground at a shallow angle: the latter case will be mainly treated in this Recommendation. In terms of scale and capability, guided boring and directional drilling tend to fall between the techniques of impact moling and microtunnelling. The terms "guided boring" and "directional drilling" are, for the purposes of the Recommendation, interchangeable. The latter term is frequently used to describe the heavier end of the market such as major river, canal and highway crossing often covering long distances, but there is now such an overlap in equipment capabilities that it is probably unnecessary and unhelpful to draw a line between the two. + +Installation of the product pipe or duct is usually a two-stage operation. A pilot hole is first drilled along the required path (see Figure I.1a) and the bore is then back-reamed to a larger diameter to accommodate the product pipe (see Figure I.1b). During this second pull-back stage, the product pipe is attached to the reamer by means of a swivel connector and is pulled into the enlarged bore as the drill string is withdrawn. In difficult ground conditions, or where the bore enlargement is considerable, there may be one or more intermediate reaming stages during which the bore diameter is increased progressively. + +Equipment capabilities have improved in recent years and the advantages of trenchless technology for new construction have become more widely appreciated. Some utility companies are now prejudiced against using open-cut techniques (particularly in roads) where a no-dig alternative is available. Apart from the obvious environmental benefits of trenchless installation, the relative cost of guided boring has fallen to below that of trenching for many applications, even ignoring the social costs of traffic disruption and delay. + +#### **1.1.1 Methods** + +Most, but not all, guided boring machines use a fluid-assisted drill head which is pushed through the ground on the end of a string of drill pipes. The drill head is usually angled so that constant rotation of the drill string produces a straight bore, whereas keeping the head in one position causes the line to deviate. A sonde or beacon is usually built into the head or fixed close to it and signals emitted by this are picked up and traced by a receiver on the surface, so allowing the direction, depth, and other parameters to be monitored. Hard-wire guidance systems are also used, with the cable running through the drill string, particularly in cases where the bore path cannot readily be traced on the surface (across rivers, for example), or where the depth of the bore is too great for accurate location by the radio-frequency methods. There are also location systems which use magnetometry. + +A bentonite/water mix is often used as the drilling fluid or "mud", which carries the debris in suspension and may be filtered through a recirculation system. On completion of the pilot bore, the thixotropic mud stabilizes the hole ready for back-reaming. The service pipe or duct, generally polyethylene or steel, is drawn in behind the reamer as the original bore is enlarged. + +In the case of larger machines, much of the work is done by the rotation of the drill string and the torque of the unit is as vital as the axial thrust and pull-back. As with smaller rigs, it is normal practice to drill a smaller pilot hole and then to back-ream to the required diameter while pulling in the conduit behind the reamer, using a drilling fluid to assist the cutting operation and to lubricate and cool the cutting head. The fluid may also power a down-hole "mud motor" for cutting rock and other hard formations, in which case higher fluid flow rates are necessary. + +Some systems are designed for dry operation without the use of water drilling fluids. These are simpler to operate, create less mess and do not require as much on-site equipment, but there may be restrictions on the sizes that can be installed, and on the ground conditions, with which the machines can cope. + +An increasingly common feature is the use of percussive action to complement axial force and rotation. This can be achieved either with a percussive hammer at the bore-head, or by generating the percussion at the machine on the surface and transmitting it along the drill string. Either way, this can significantly improve the ability of guided boring machines to punch through difficult ground or hard inclusions. + +![Figure I.1a/L.38: General scheme of the directional drilling technique: drilling the pilot hole. The diagram shows a cross-section of the ground with a 'Guided boring machine' on the surface at the start. A 'Drill pipe' is being used to create a 'Bore path' that curves downwards and then upwards to a 'Reception pit'. Along the bore path, several circles represent 'Existing services' that the drill is avoiding. The background shows houses and trees above ground.](ef96fcba3a34e9e35ff8ee3cc8cb7b20_img.jpg) + +Figure I.1a/L.38: General scheme of the directional drilling technique: drilling the pilot hole. The diagram shows a cross-section of the ground with a 'Guided boring machine' on the surface at the start. A 'Drill pipe' is being used to create a 'Bore path' that curves downwards and then upwards to a 'Reception pit'. Along the bore path, several circles represent 'Existing services' that the drill is avoiding. The background shows houses and trees above ground. + +T0604320-98 + +**Figure I.1a/L.38 – General scheme of the directional drilling technique: drilling the pilot hole** + +![Figure I.1b/L.38: General scheme of the directional drilling technique: backreaming and pulling in the product pipe. This diagram shows the same setup as Figure I.1a, but now a 'Reamer fitted to drill string' is at the end of the drill pipe, enlarging the bore path. A 'Product pipe' is being pulled back into the bore path from a 'Pipe coil' at the reception pit end. The 'Guided boring machine' remains at the starting point.](b25cc68846b070bbe56a949b011ba91c_img.jpg) + +Figure I.1b/L.38: General scheme of the directional drilling technique: backreaming and pulling in the product pipe. This diagram shows the same setup as Figure I.1a, but now a 'Reamer fitted to drill string' is at the end of the drill pipe, enlarging the bore path. A 'Product pipe' is being pulled back into the bore path from a 'Pipe coil' at the reception pit end. The 'Guided boring machine' remains at the starting point. + +T0604330-98 + +**Figure I.1b/L.38 – General scheme of the directional drilling technique: backreaming and pulling in the product pipe** + +#### I.1.2 Drilling machines + +Manufacturers throughout the world offer a variety of equipment, ranging from compact rigs for small diameters and short lengths, to very large machines capable of installing well over a kilometre of large diameter pipes. An equally extensive range of bore guidance systems, drill heads, reamers and accessories, is also available. + +Surface-launched rigs are often track-mounted and can be moved into position under their own power. Whilst they do not require starter or reception pits to install the new pipe, excavations are nevertheless required to make connections at each end. Assuming that these connecting pipes are at some depth below the ground, the first few metres of new pipe may be wasted in drilling down to the required depth. + +Some of the more compact machines can work from an excavation only slightly larger than that needed to make a joint after installation, or directly from existing chambers or manholes. These machines are generally intended to drill fairly straight and often use stiffer drill pipes than surface-launched systems. There are, therefore, greater limitations on their ability to steer around obstacles. The length of individual sections of drill pipe is also restricted by the dimension of the excavation and this may influence the speed of installation and the cost of the drill pipe. + +##### **1.1.2.1 Fluid-assisted bore** + +There are three essential features of any fluid-assisted guided boring machine. The first is a powered rack which pushes the drill string through the ground to bore the pilot hole and then pulls it, and the product pipe, through the bore during the backreaming operation. Typically, the inclination of the rack on a surface-launched rig can be adjusted between about 10° and 20° to the horizontal. The second feature is a motor and drive system to rotate the drill string (together with the attached bore head or backreamer) and provide rotational torque. The third is an hydraulic system to produce a low or high pressure mud jetting which, for some machines, represents the main drilling force. + +Pit-launched machines are fixed in position, within the launch pit or chamber/manhole, using their rear and front faces to provide reaction to the thrust and pullback forces. + +Surface launched rigs have some form of stake-down system to anchor them to the ground. On the more sophisticated machines, the stake-down system may be hydraulically powered. Some surface-launched machines are self-contained, having on-board mixing tanks and pumps for the drilling fluid, together with associated power supplies, valves and control systems. Alternatively, separate fluid is pumped through the hollow drill string to the bore-head and returns through the space between the drill string and the walls of the bore. The fluid, together with the excavated material mixed with it, is usually pumped into a filtration unit for separation and recycling. + +Drilling rigs, especially surface-launched machines, may incorporate an automatic drill pipe loading system in which the lengths of drill pipe are contained in a "carousel" and are automatically added to or removed from the drill string as boring or back-reaming progresses. This may operate in conjunction with an automatic vice arrangement which screws the drill pipes together or unscrews them during back-reaming. Automatic pipe handling is becoming increasingly common, even in smaller machines, since it speeds up installation, improves safety and reduces manpower requirements. + +The choice of backreaming tools and accessories is very wide and most have particular design features that are claimed to enhance performance. Most reamers are bullet-shaped with an arrangement of tungsten carbide teeth and fluid jets. The rear of the reamer has a coupling to which a towing head can be attached for pulling in the product pipe. Special designs are available for difficult ground conditions, including hole-openers for reaming in rock. + +Specific fluid assisted systems for rock drilling have been designed: double tube system, "head casing" system, mud motors. + +The double tube system uses a double set of coaxial drill tubes. The inner tubes drive the head bit (typically a three cone cutting head) and the reamer, while the outer tubes enable the rotation of a pre-threaded sensor holder to allow the drilling guidance. + +As for the double tube set, and also for the head casing system, the principle applied is a mechanical drive to a three cone head via the tube set but, instead of using a second set of coaxial tubes, the head guidance is provided by the position in the ground of an asymmetrical "case" around the first tube that may be locked or unlocked at will and which is used to direct the run in the required direction. + +Mud motors are placed in the front of a tube line. They have a bend in them so that they may be directed. An hydraulic motor (rotor and stator) driven by a high pressure mud flow turns the cutting tool (three cone head with hard inserts – carbide or even diamond) located on the mud motor head. Guidance may be performed by cables assembled on the tubes as they progress or by detector. + +##### **I.1.2.2 Dry boring** + +Whilst most guided boring machines use a drilling fluid to lubricate the bore-head, convey waste material back to the starting pit and stabilize the bore, some systems are designed for dry operation. Both surface-launched and pit-launched versions are available and dry boring machines tend to be more compact and simpler than most fluid-assisted rigs. + +Instead of relying entirely on thrust and rotation generated at the rig, dry boring machines use a high frequency pneumatic hammer at the bore head to penetrate and compact the ground for the pilot bore. In this respect, the concept is not unlike an impact mole on the end of hollow drill pipes which also acts as the pneumatic feed. As with fluid-assisted systems, the chisel head in front of the hammer is angled, allowing the bore to be steered by stopping the rotation at a particular orientation. + +For small diameter pipe, duct or cable installation (up to about 65 mm diameter) using dry methods, a cone shaped reamer with tungsten-carbide cutting teeth may be connected directly to the drilling rods. The expander is fitted with air jets, fed through the drill string and a high velocity air flow helps to clean out the bore during backreaming. The expander is rotated and pulled back to enlarge the bore, with the pipe attached to the rear using a swivel connector and some form of towing head. + +For the dry installation of pipe diameters up to 250 mm, a pneumatically powered reaming hammer is used, again with the pipe string attached to the rear of the device by means of a swivel. The percussive effect of the reaming hammer, rather than the pull-back force of the machine, is the main agent in expanding the bore and no rotation is required during backreaming. As with the pneumatic hammer used for the pilot hole, the air supply for the reaming hammer is conveyed through the drill string. + +Some machines, combining the percussive action of a pneumatic hammer in the drilling head and the thrust and pullback actions, as well as rotation of hydraulics, allow one to perform directional drilling even in hard rock. The high-pressure air which feeds the pneumatic hammer is also used, mixed with very low percentage of water and biodegradable additive (water mist lubrication), to lubricate the drilling tools and the bore, and to moisten and loosen the soil, increasing productivity in dry soil conditions. During the drilling process the compressed air removes all debris, leaving a clean hole and no fluid residue. + +#### **I.1.3 Drill pipes** + +Considerable physical demands are made of the drilling pipes. They should have sufficient longitudinal strength to withstand the thrust and pull-back forces, enough torsional stiffness to cope with the rotational torque of the machine and yet be flexible enough to negotiate changes of direction in the course of the bore. They should also be as light as possible to facilitate transportation and handling, whilst resisting damage due to abrasion and scoring. The length of individual pipes depends on the type of drilling machine and the space available. Typically, surface launched rigs will use pipes up to 4 to 5 metres long, whilst drill pipes for pit-launched machines are often between 1.0 and 1.5 metres in length. Screw joints are most commonly used, although bayonet fittings are found with some systems. + +Most drilling machine manufacturers offer their own proprietary brands of drill pipes and there are also specialist companies producing a variety of alternatives. Obviously, it is important to ensure that the drill pipes are wholly compatible with the drilling machine, especially if the rig incorporates an automatic drill pipe handling system, and also with other components such as bore-heads, sondes and reamers. + +#### **I.1.4 Drilling fluids** + +Depending upon its formulation, the drilling fluid may have several functions: + +- to lubricate the cutting head and reduce wear; +- to soften the ground so that it is easier to drill through; + +- to convey excavated material in suspension back to the launch pit; +- to stabilize the bore prior to backreaming; +- to lubricate the product pipe during backreaming and insertion; +- to power mud motors for drilling through hard ground. + +The simplest drilling fluid is water and it may be unnecessary to use anything more sophisticated for short bores of small diameter through good ground. + +A mixture of bentonite and water is the most common type of drilling fluid or "mud". Bentonite is a type of clay with thixotropic properties, meaning that it remains fluid as long as it is being pumped or agitated, but forms a gel if allowed to stand. If agitated again, it reverts to a fluid. The material therefore acts as a lubricant and carrier during the drilling operation, but solidifies to stabilize the bore once drilling stops. During backreaming, the mud helps to provide lubrication between the product pipe and the walls of the bore, and reduces soil regression and friction. + +In addition to simple water/bentonite fluids, there are polymer-based materials and a wide range of additives which are used to tailor the properties of the drilling fluid to suit the soil conditions and the nature of the project. For example, the viscosity should be low enough to flow through the system at reasonable pressures, but sufficiently high to prevent significant loss into the ground. + +The formulation of drilling fluid is a complex science in its own right and one which plays a major part in the success of projects. Most manufacturers of drilling machines have their own recommendations on the most suitable fluids for particular applications and advice is also available from the manufacturers of the materials. This is an area where specialist guidance should be sought, especially when dealing with difficult ground conditions. The design of a mixing, pumping, filtration and recycling plant is also a major consideration, especially for large-scale projects and again advice should be sought from experienced contractors and manufacturers. + +#### **1.1.5 Tracking and guidance systems** + +Most guided boring techniques, other than some short-distance pit-launched applications, rely on accurate bore location and guidance systems. The capability of tracking devices has improved considerably with advances in electronic technology and a high degree of accuracy is now achievable. + +There are several types of tracking system. The most common, known as "walk over" systems, are based on a sonde or beacon contained in a housing behind the bore-head. This emits a radio signal which is picked up by a receiver on the surface. In addition to giving position and depth of the bore-head below the ground, the data transmitted will often include the inclination of the drill bit, the orientation of the head, beacon battery status and beacon temperature. It is common for this information to be relayed to a satellite receiver at the drilling machine, so that the rig operator has direct access to the data and can make any necessary steering adjustments accordingly. + +Walk over systems are, in many respects, similar to pipe and cable detectors in that the receiver is moved to a position which gives the strongest signal, at which point it should be directly above the beacon. Their main limitation is the need to gain access to the surface directly above the bore-head, which may be difficult, or impossible, if the line runs under a building or beneath a body of water. This may be overcome by using either a "hard wire" guidance system, or a beacon containing an on-board electronic compass. + +Hard wire systems use a cable running through the drill string to transmit data from the beacon to the control console. Whilst the cable is an added complication, it allows bore tracking across any terrain without relying on the transmission of radio signals and can also be used in locations affected by electromagnetic interference. + +When initialized to a predetermined azimuth heading, a compass beacon notifies the operator when the bore-head has deviated from the intended bore path. The left/right deviation information is sent to a tracking receiver and is displayed in a format similar to pitch and roll information. The operator does not have to be above the beacon or on the intended bore path and, in some cases, data can be received at distances of over 300 metres from the beacon. + +Because of the operating environment, beacons must be extremely durable and resistant to shock and vibration. This applies particularly in the case of drilling rigs with percussive action, where some form of shock-absorption mechanism is likely to be required. + +To avoid subjecting electronics to severe dynamic loading, a location and guidance system based on magnetometry is used with dry guided boring machines which employ percussive hammer action. Permanent magnets are housed in a section of the pilot hammer and a magnetic field is detected by magnetometers on the surface and a computerized processing unit translates this data to give the location, depth and roll angle of the bore-head. As with radio beacons, the tracking information can be relayed to the drill operator's console. + +#### **I.1.6 Ancillary equipment** + +Although most attention is focused on major items of equipment, there are numerous accessories and ancillaries which play an important part in the success of a guided boring or directional drilling project. + +Various types of towing heads for polyethylene pipes are available, including pressure-tight heads and versions aimed specifically at directional drilling. One function of directional drilling towing heads is to prevent the ingress of drilling fluid or debris into the product pipe. Swivel connectors are an essential component during the backreaming and pipe-pulling operation and should be designed to prevent the entry of mud and debris to the bearings. Models are available with capacities from less than 5 to over 200 tonnes. + +Some contractors use "breakaway connectors" to protect the product pipe. The connectors have a series of pins designed to break under a predetermined load and are set according to the permissible tensile load on the product pipe. Not only do breakaway connectors reduce the risk of inadvertent damage, there is also a psychological effect on operators who are aware that the permissible pulling force cannot be exceeded and therefore resist the temptation to increase the load for higher productivity. + +Other important ancillary equipment may include butt-fusion machines for jointing polyethylene pipes, pipe support rollers and cable pullers. + +### **I.2 Impact moling** + +Impact moling, or "earth piercing" as it is commonly known in North America, is defined as the creation of a bore by the use of a tool which comprises a percussive hammer within a suitable cylindrical casing, generally torpedo shaped (see Figure I.2). The hammer may be hydraulic or pneumatic. The term is usually associated with non-steered or limited steering devices without rigid attachment to the launch pit, relying for forward movement upon the internal hammer action to overcome the frictional resistance of the ground. During operation the soil is displaced, not removed. An unsupported bore may be formed in suitable ground, or a pipe may be drawn or pushed in immediately behind the impact moling tool. Cables may also be pulled in. + +Although hydraulically driven percussive moles are available, most are powered by compressed air. A potential drawback of air-driven moles is contamination of the product pipe by lubricating oil in the exhaust, although there are methods of overcoming this. Hydraulic moles require two hoses (flow and return) and tend to have greater mechanical complexity. + +The basic mechanism of impact moling is the reciprocating action of the pneumatically or hydraulically powered hammer within the cylindrical steel body. The piston is driven forward and, on striking the forward end of the unit, imparts its kinetic energy to the body which is driven forward. The energy of the piston for the return stroke is regulated so as to reposition it for the next forward stroke, rather than reversing the unit out of the bore (unless required to do so). + +Repeated impacts of the hammer piston advance the whole unit through the ground. As forward movement takes place, the soil in front of the mole is forced aside and compacted by the conical or stepped nose to form the walls of the bore. The power of the unit is also often used to pull the product pipe, cable or cable duct through the bore at the same time as the impact mole advances. + +Impact moling tools are known by several other names including earth piercing tools, soil displacement hammers, impact hammers, percussive moles or pneumatic moles, depending on the term used by the manufacturer and the region of the world where the equipment is being used. + +![Diagram illustrating pipe installation by impact moling. A cross-section shows a 'Launch pit or chamber' on the left where a 'New PE pipe' is being introduced. An 'Impact mole' is shown advancing through the ground from the launch pit towards a 'Reception pit or chamber' on the right. The background shows a surface view with houses and trees.](8f931bb1d65d0ee4ccafab751ee61282_img.jpg) + +Diagram illustrating pipe installation by impact moling. A cross-section shows a 'Launch pit or chamber' on the left where a 'New PE pipe' is being introduced. An 'Impact mole' is shown advancing through the ground from the launch pit towards a 'Reception pit or chamber' on the right. The background shows a surface view with houses and trees. + +T0604340-98 + +**Figure I.2/L.38 – Pipe installation by impact moling** + +#### **I.2.1 Monitoring** + +Most moles can now be fitted with radio sondes, similar to those used for monitoring the progress of directional drilling units, which allow the progress of the mole to be followed closely both in direction relative to the planned course and in depth. Sondes can be fitted either to the rear of the impact mole or, in some cases, within the front end. + +Although rear-mounted sondes give an indication of progress, they provide less useful information than front-mounted units. Depending on the mole size and length, the sonde can be some distance from the penetrating end of the tool and therefore responds much later than a front-mounted sonde to changes in direction and pitch and so give the operator more time to halt the bore and assess the next move. However, nose-mounted sondes have to be far more robust and well protected, as they must withstand the shock of the drive forces applied to the front of the unit by the hammer action. + +If a bore is forced off-line or prevented from advancing by an obstacle, it is often easier to dig down to the unit, remove the obstruction, realign the mole and relaunch it rather than to start the bore again. This is often aided by the reversing facility that most impact moles now have, which enables the unit to be backed away from an obstruction to a point where it was on the correct line and level. After removing the obstacle and backfilling the hole, the mole is restarted on the intended course + +#### **I.2.2 Head types** + +Two basic head shapes are commonly used for impact moles. The first is the simple cone which, during operation, pierces the ground and pushes the soil aside. The second is the step or chisel head, which is effectively a stepped cone. In normal operation the spaces between the steps fill with soil and the head operates a simple cone. However, when the head strikes an obstacle, the stepped edges concentrate the impact energy against the obstruction. Whereas a smooth cone would tend to be deflected by an obstacle, the stepped shape may apply sufficient longitudinal force to move the obstruction, or shatter it, reducing the risk of going off line. + +Most moles have fixed heads, which means the head is an integral part of the mole body once the unit is assembled. When the piston operates, it acts on the whole of the mole body propelling it forward. + +An alternative is the moving head mole in which the head is not directly attached to the body but floats on a shaft passing through the front end of the mole. The rear of this shaft is the anvil against which the reciprocating hammer strikes. Using this configuration, the initial and highest impact force from the hammer is transferred to the head alone, advancing it into the ground. Several advantages for this system are claimed, including higher impact energy to penetrate harder ground and move or break up obstacles. The body of the mole acts as an initial directional anchor to the head as it drives forward, giving better directional control. + +### **I.3 Pipe ramming** + +Pipe ramming is a non-steerable system of forming a bore by driving a steel casing, usually open-ended, using a percussive hammer from a drive pit. The soil may be removed from an open-ended casing by augering, jetting (with water) or compressed air. In appropriate ground conditions a closed casing may be used. + +#### **I.3.1 Set-up** + +A typical ramming operation requires the establishment of a solid base, normally a concrete mat, on the launch side of the installation. This mat will usually be either against the side of a slope or in a start pit. Guide rails set to the line of the bore are then installed on the mat. The first length of steel pipe is positioned on the guide rails, a cutting edge is formed or fitted to the lead end of the pipe, and the ramming hammer is attached to the rear of the pipe. Depending on the diameter, inserts may have to be used to ensure solid and uniform contact between the hammer and the pipe. + +The power supply is attached and the hammer started. The ramming hammer forces the steel pipe into the ground along the line dictated by the guide rails. When one pipe has been driven the hammer is stopped and removed and the next length of steel pipe is welded in place. The cycle is repeated until the leading edge of the first pipe arrives at the reception end or shaft. + +As with impact moling, thorough ground investigation is an essential requirement of pipe ramming projects. Large obstacles can deflect a pipe, or may damage the cutting edge, causing a steering bias. As there is usually no means of monitoring the direction of the pipe during a bore, it is vital to establish a clear bore path prior to work commencing. + +#### **I.3.2 Bore options** + +Depending on the nature of the ground, ramming may be carried out with either open-ended or closed-end pipe. Open-ended ramming is generally preferable, having several advantages including lower reaction against the ramming force, since only the cutting edge is pushed against the ground. Harder ground can be penetrated by open-ended ramming as the soil does not have to be compressible. Because the surface area of pipe presented to an obstacle is far less with an open-ended pipe, there is also less likelihood of the pipe deflecting. + +However, for open-ended ramming the ground has to be relatively self-supporting, otherwise there may be loss of ground ahead of the cutting edge as soil moves into the open pipe and flows along it to the start pit. In severe cases, this could cause surface subsidence or loss of support to adjacent pipelines. Closed-end ramming may be effective under such conditions as soil is displaced around the pipe and compacted around the wall of the bore. + +When using an open-ended system, the cylinder of ground within the circumference of the cutting edge stays inside the pipe during the bore. Over the short distances, normally undertaken with pipe ramming, this accumulation of spoil is not usually a problem. However, for long bores, it should be remembered that the spoil adds to the weight of the pipe string being rammed and will therefore affect advance rates. In some instances it may be advisable to clean out spoil from the pipe during pipe string extension works, to limit the extra burden on the ramming hammer. Depending on diameter, this can be done either manually or by means of a scraper. + +If intermediate cleaning is not required, and the spoil remains in the pipe for the whole bore, there are techniques other than shovels or scrapers for achieving spoil removal. On arrival at the reception pit, the open end of the pipe can be sealed with a suitable plug. Pressurized water or compressed air is then introduced between spoil and seal, and the cylinder of soil in the pipe is forced out into the launch pit where it can be removed. The seal is then removed and the pipe or casing cleaned and put into service. + +The principles of both impact moling and pipe ramming are relatively simple and these techniques can offer highly cost-effective solutions to relatively short length installation projects. + +### **I.4 Pipejacking and microtunnelling** + +Pipejacking and microtunnelling are essentially from the same family of pipeline installation techniques, used for installations from about 150 mm diameter upwards (see Figure I.3). A pipejack is defined as a system of directly installing pipes behind a shield machine by hydraulic jacking from a drive shaft, such that pipes form a continuous string in the ground. The pipes, which are specially designed to withstand the jacking forces likely to be encountered during installation, form the final pipeline once the excavation operation is completed. + +Within this description, microtunnelling is specifically defined as being a steerable remote-controlled shield for installing a pipejack with internal diameter less than that permissible for man-entry. Microtunnellers often use a laser guidance system to maintain the line and level of the installation, though, as with larger pipejacking installations, both laser guidance and normal survey techniques can also be utilized. + +Systems are available for the installation of both main pipelines and branch connections. + +![A cross-sectional diagram illustrating the installation of pipes using microtunnelling. The diagram shows a 'Launch pit' on the left and a 'Reception pit' on the right. A 'Microtunnelling machine' is positioned in the center, with an arrow indicating its forward movement. A series of 'Jacking pipes' are being pushed from the launch pit towards the machine. These pipes are supported by an 'Alignment and jacking frame' at the launch pit, which is also equipped with 'Hydraulic jacks'. The pipes are connected by 'Flush-fitting collars'. The background shows a residential area with houses and trees, suggesting the operation is taking place underground beneath a built-up area. A small code 'T0604350-98' is visible in the bottom right corner of the diagram.](60ee3da582d29b56f1d2e705f6fc4588_img.jpg) + +A cross-sectional diagram illustrating the installation of pipes using microtunnelling. The diagram shows a 'Launch pit' on the left and a 'Reception pit' on the right. A 'Microtunnelling machine' is positioned in the center, with an arrow indicating its forward movement. A series of 'Jacking pipes' are being pushed from the launch pit towards the machine. These pipes are supported by an 'Alignment and jacking frame' at the launch pit, which is also equipped with 'Hydraulic jacks'. The pipes are connected by 'Flush-fitting collars'. The background shows a residential area with houses and trees, suggesting the operation is taking place underground beneath a built-up area. A small code 'T0604350-98' is visible in the bottom right corner of the diagram. + +**Figure I.3/L.38 – Installing pipes by microtunnelling** + +#### I.4.1 Planning + +In the early years of development of microtunnelling, some projects were designed around an existing plan to install a pipeline using open cut techniques. Often this was due to the design engineer's lack of knowledge of trenchless technology in general. Contractors were then required to offer an alternative installation using pipejacking technology. Unfortunately, this was inefficient as it took no account of the option to "short cut" pipeline routes which had been constrained by access criteria for open cut operations, such as having to follow roads, avoid crossing private land and be in areas large enough to accommodate excavation equipment. + +Most pipejacks and microtunnels are now planned to remove these restrictions almost completely. By knowing the hydraulic requirements of the pipe, its connection points, the ground types to be encountered and the limitations of access along the required route, shaft positioning, depth and size can be designed in such a way as to minimize the number of excavations required, and thus reduce the number of individual drives on any pipeline. + +Such planning not only minimizes the physical impact of a construction project by limiting the duration of the work, but also reduces the environmental effects of the project in terms of traffic disruption and amount of ground disturbed. Optimization of the pipeline length also saves on the quantities of materials required for the project. A further advantage of restricting the amount of excavation is that many clients and highway authorities now insist on the replacement of excavated soils with higher quality backfill. This results in the need to transport and dump excavated material and to quarry the backfill material. The use of no-dig or minimum excavation techniques reduces the disruption and expense of transportation, quarrying and tipping, whilst also conserving natural materials. + +#### **I.4.2 Excavation and spoil removal in pipejacking** + +Several different excavation techniques are used in pipejacking. The first requirement for either a pipejack or a microtunnel is that a drive shaft should be sunk. The design of the shaft depends on the installation required, the size depending particularly on the lengths of the pipes to be installed. In both cases there is a need to establish a thrust wall against which the jacking frame can operate without causing damage to, or misalignment of, the shaft itself. + +For the excavation of the ground within the pipejack, the first technique is basic hand excavation using an open shield whereby a miner utilizes hand tools, whether powered or not, to remove the ground ahead of the shield. In more difficult ground conditions it is possible to use a backacter, cutter boom or rotating cutter head arrangement. In most cases, these systems are used in conjunction with open face shields and rely, to a large extent, on the ground at the face being self-supporting to some degree. Excavated spoil is removed from the face using mucking skips which are rail-mounted and winched to and from the face by a continuous rope system. Alternatively, there may be a conveyor-belt which loads into a hoisting system at the shaft bottom. + +There have been instances where a vacuum system has been employed to remove spoil whereby broken ground is sucked out of the tunnel. A "soft slurry system" has also been developed in which a vacuum is used to discharge the slurry. + +Where the ground is not self-supporting, a closed face shield is generally required. Under such conditions, excavation is carried out by rotating cutter head. The spoil removal technique maintains a sufficient level of support at the face by using either a spoil removal slurry under pressure, or by limiting the amount of broken ground within the cutter chamber at a level sufficient to give face support. The latter system is known generally as Earth Pressure Balance. + +#### **I.4.3 Excavation and spoil removal in microtunnelling** + +Two predominant systems of spoil removal are employed at the smaller diameters associated with microtunnelling. In self-supporting soils, where the head of ground water pressure does not exceed about three to four metres, it is possible to use an auger flight to remove broken ground. The auger chain is established in an auger casing within the jacking pipe. The auger feeds spoil to a muck skip positioned beneath the jacking frame in the start shaft. When full, this is hoisted to the surface, emptied and returned before the drive is continued (see Figure I.4). + +![Diagram of an auger excavation method showing the front casing, front screw, auger head, driving pipe, screw conveyor casing, screw motor, power unit, and rear-end jack.](1ce750ac0d53b8e532abdeabf7740611_img.jpg) + +A schematic diagram of an auger excavation system. On the left, the 'Auger head' is shown at the end of a 'Front screw' which is housed within a 'Front casing'. This assembly is connected to a 'Driving pipe'. Inside the driving pipe is a 'Screw conveyor' which is enclosed in a 'casing'. The screw conveyor is driven by a 'Screw motor' located at the rear. The screw motor is connected to a 'Power unit' at the top. The entire rear assembly is supported by a 'Rear-end jack' at the bottom right. A reference code 'T0604360-98' is visible in the bottom right corner of the diagram. + +Diagram of an auger excavation method showing the front casing, front screw, auger head, driving pipe, screw conveyor casing, screw motor, power unit, and rear-end jack. + +**Figure I.4/L.38 – Example of auger excavation method** + +In more difficult ground conditions, and at higher ground water heads, a recirculating slurry system is often used (see Figure I.5). The slurry system requires a suspension of bentonite or specially designed man-made polymer (or a combination of the two) to be prepared at the surface. This suspension is pumped to the cutter chamber via a system of pipes arranged within the jacking pipe. If necessary, the slurry is pressurized to a level required to maintain face support. In the cutter chamber, the slurry mixes with the excavated ground and this mixture normally passes through an in-built crusher with an eccentric radial motion to ensure that no ground particle, larger than the slurry system can handle, enters the return side of the system. + +The mixture is pumped to the surface where the soil particles are removed from suspension by simple gravity decantation or by using centrifugal forces within hydrocyclones or similar apparatus. Chemical flocculents are sometimes added to improve efficiency. The newly cleaned slurry is monitored and reconditioned by the addition of further chemicals, to meet the specification required at the face, and recycled through the system. + +![Diagram of the slurry method for pipe driving. The diagram shows a 'Driving machine' connected to a 'Driving pipe'. The driving pipe is inserted into the ground, where 'Slurry pressure and earth pressure are balanced'. Above ground, an 'Adjustment tank' is connected to the system. A 'Slurry feed pump' draws from the tank and pumps slurry into the driving pipe. A 'Slurry discharge pump' draws from the driving pipe and pumps slurry back to the adjustment tank. A 'Pit bypass' line with valves is also connected to the driving pipe. The driving machine is connected to '1st disposal equipment'. On the right, a 'Rear-end jack' is shown at the end of the driving pipe. A 'Control panel' and a 'Power unit' are connected to the rear-end jack and the control panel.](08dce7ad4c512fdf0c0cde60415fade6_img.jpg) + +Diagram of the slurry method for pipe driving. The diagram shows a 'Driving machine' connected to a 'Driving pipe'. The driving pipe is inserted into the ground, where 'Slurry pressure and earth pressure are balanced'. Above ground, an 'Adjustment tank' is connected to the system. A 'Slurry feed pump' draws from the tank and pumps slurry into the driving pipe. A 'Slurry discharge pump' draws from the driving pipe and pumps slurry back to the adjustment tank. A 'Pit bypass' line with valves is also connected to the driving pipe. The driving machine is connected to '1st disposal equipment'. On the right, a 'Rear-end jack' is shown at the end of the driving pipe. A 'Control panel' and a 'Power unit' are connected to the rear-end jack and the control panel. + +**Figure I.5/L.38 – Example of slurry method** + +The slurry system has the advantage of being continuous whereas auger-based methods, which require the hoisting of spoil, are more cyclical and involve interruptions to the operation of the cutting head. + +There is also a system which utilizes a hydraulically controlled sealing door to limit the ground removed during excavation, with spoil removal being completed using a scraper system within the jacking pipe. This system does not normally use a cutter head but relies on a cutting rim on the leading edge of the shield to loosen the ground, causing it to fall away from the face. The technique has been used successfully, but its application is restricted compared with the two main system types due mainly to limitations on the ground types in which it can operate. + +Some systems use the so called slurry pressure balanced method (see Figure I.6). Such systems mount a pressure balanced slurry discharge type driving machine onto the tip of a driving pipe. Soil is excavated by rotating the cutters while at the same time maintaining the stability of the soil by adopting a water-stopping valve and injecting additives to promote plastic liquefaction of the excavated soil. The excavated soil is mixed with slurrizing water to create slurry which is then discharged in liquid form via a pipe passed through the driving pipe or guide pipe. Like the slurrizing water system, driving is performed while adjusting the amount of additives injected and the driving speed to stabilize the soil. Bentonite or polymer-based additives are selected according to the soil quality. + +The water pressure balance method balances the soil using water pressure instead of slurrizing water, and is used for soil with a low water pressure such as water-filled sandy layers. + +![Diagram of the slurry pressure balanced method for microtunnelling.](7ae836e598020d937ed1478c2ef13025_img.jpg) + +This diagram illustrates the slurry pressure balanced method for microtunnelling. On the surface, there is a Control Panel, a Power Unit, a Pump for Lubricant, and a Slurry Tank. A Discharge Pipe connects the pump to the Driving Machine. The Driving Machine is positioned at the entrance of a tunnel. Inside the tunnel, a Feeding Pump is located near the Cutter Head. Lubricant is injected into the tunnel ahead of the cutter head, and Slurry is shown being removed from the tunnel face. An Inlet Port for Discharge is also indicated. The tunnel extends from the Driving Machine through a Starting Shaft. The diagram is labeled T0604380-98. + +Diagram of the slurry pressure balanced method for microtunnelling. + +**Figure I.6/L.38 – Example of slurry pressure balanced method** + +Two other specialized microtunnelling techniques are available for bores of up to about 300 mm diameter. The first is a simple compaction method (penetrating or press-in method, see Figure I.7) in which the rotating cutter head of the microtunneller does not remove the ground from the face so much as push it aside, compacting it around the perimeter of the bore. + +![Diagram of the penetrating method for microtunnelling.](05eb72d372e4bf78e3d6a64949d77bcc_img.jpg) + +This diagram illustrates the penetrating method for microtunnelling. On the surface, there is a Control panel and a Power unit. A Starting Shaft leads down to the Driving machine. The Driving machine is connected to a Driving pipe. The Driving pipe extends through the Starting Shaft and into the ground. A Rear-end jack is located at the rear of the Driving machine, within the Starting Shaft. The diagram is labeled T0604390-98. + +Diagram of the penetrating method for microtunnelling. + +**Figure I.7/L.38 – Example of penetrating method** + +This system is limited to compactable soil types. The second (boring method) employs an excavation method which can be compared with that used by the majority of directional drilling machines. The cutter is an angled rotating head which, when rotated, bores in a straight line. When held at a certain angle, the bias of the angled head allows steering to take place. This system normally uses an auger + +spoil removal technique and requires either a reaming phase, prior to pipe installation, or an expander in front of the lead pipe during pipejacking. The system is often used as a two pass installation with the pipe starting to be installed only after the initial pilot bore has been completed. + +To complete a drive using either pipejacking or microtunnelling, a reception shaft is needed. The dimensions of this shaft should be such that the pipejacking or microtunnelling shield can be recovered without difficulty. As these shafts are not normally used for jacking operations there is no need for abnormal strengths or thrust wall. + +#### I.4.4 Microtunnelling work method classification + +Work methods are broadly divided into high strength and low strength systems, depending on the type of driving pipe, and then subdivided further according to the excavation and soil discharge systems. High strength systems transmit the driving force directly to high strength pipes. In contrast, low strength systems pass a driving force transmission rod and a traction rod through low strength pipes and then drive these rods so that the driving force is not transmitted directly to the low strength pipes. Thus, the tip resistance acts only on the transmission and traction rods, and the low strength pipes must bear only the friction between the soil and the outer surface of the pipes (Figure I.8). + +![Diagram illustrating the high strength pipe method and low strength pipe method for microtunnelling.](9870bf462aa0d916a16d14b5a100c60a_img.jpg) + +The diagram is divided into two horizontal sections. The top section, titled 'High strength pipe method', shows a 'Driving machine' on the left connected to a 'High strength pipe'. A 'Rear-end jack' is on the right. Arrows labeled 'Driving force' point from the jack and the machine into the pipe. The bottom section, titled 'Low strength pipe method', shows a 'Driving machine' on the left connected to a 'Low strength pipe'. A 'Rear-end jack' is on the right. A 'Driving force carrying rod' is shown inside the pipe, with arrows labeled 'Driving force' pointing from the jack and the machine into this rod. Both diagrams include a small code 'T0604400-98' or 'T0604410-98' near the rear-end jack. + +Diagram illustrating the high strength pipe method and low strength pipe method for microtunnelling. + +**Figure I.8/L.38 – High strength pipe method and low strength pipe method** + +In addition, there are also single-stage systems in which the driving machine and pipes are directly driven, and two-stage systems in which first the driving machine and a guide pipe are driven and then the conduit pipes are driven along the guide pipe. Two-stage systems generally support wider pipe diameter and driving distance ranges than single-stage systems (Figure I.9). + +![Diagram illustrating the difference between first and second stage pipe driving systems. The diagram is divided into two main sections: 'First Stage' and 'Second Stage'. In the 'First Stage', an 'Arriving shaft' is on the left, and a 'Starting shaft' is on the right. Between them, a 'Driving head' is connected to a 'Driving machine', which is connected to a 'Driving pipe'. A 'Rear-end jack' is also shown at the starting shaft. In the 'Second Stage', the 'Arriving shaft' is on the left, and the 'Starting shaft' is on the right. The 'Driving head' is connected to a 'Driving machine', which is connected to a 'Lead pipe'. The 'Lead pipe' is connected to a 'Driving pipe', which is connected to 'Magnifying equipment' at the starting shaft. The diagram shows the progression of driving a pipe through two stages, with the first stage using a driving machine and pipe, and the second stage using a lead pipe to guide the driving pipe.](339be989b91d5b1e73e5ecdc8401ca75_img.jpg) + +Diagram illustrating the difference between first and second stage pipe driving systems. The diagram is divided into two main sections: 'First Stage' and 'Second Stage'. In the 'First Stage', an 'Arriving shaft' is on the left, and a 'Starting shaft' is on the right. Between them, a 'Driving head' is connected to a 'Driving machine', which is connected to a 'Driving pipe'. A 'Rear-end jack' is also shown at the starting shaft. In the 'Second Stage', the 'Arriving shaft' is on the left, and the 'Starting shaft' is on the right. The 'Driving head' is connected to a 'Driving machine', which is connected to a 'Lead pipe'. The 'Lead pipe' is connected to a 'Driving pipe', which is connected to 'Magnifying equipment' at the starting shaft. The diagram shows the progression of driving a pipe through two stages, with the first stage using a driving machine and pipe, and the second stage using a lead pipe to guide the driving pipe. + +**Figure I.9/L.38 – Difference of first stage and second stage** + +A further classification can be done considering the main driving methods: + +- auger excavation method; +- slurry method; +- penetrating or press-in method; +- slurry pressure balanced method; +- water pressure balanced method; +- boring method. + +#### **I.4.5 Position detecting methods** + +The microtunnelling method drives over long distances while controlling the direction, making it important to confirm the position of the driving machine underground. + +##### **I.4.5.1 Laser targeting method** + +A laser beam emitter is set up in the starting pit and a target made of glass or photoreceptors is mounted inside the driving machine. The position where the laser beam strikes the target is then monitored by a theodolite in the starting pit or a CCD camera inside the driving machine. The driving machine inclination can also be sensed by using two target plates. This method enables accurate sensing over straight alignments, and provides a sensing accuracy of within a few millimetres at distances up to about 100 m. + +However, when the driving distance exceeds 150 m, the laser beam becomes dispersed and the diameter of the light striking the target increases, resulting in incorrect position indications. In addition, there are also problems such as laser beam refraction due to temperature changes inside the driving pipe. + +##### **I.4.5.2 Electric magnetic induction method** + +This method estimates the position of the driving machine by mounting an electromagnetic coil inside the driving machine and sensing the strength of the electric magnetic field emitted from this electromagnetic coil above ground. This method is capable of measuring the absolute position, regardless of distance or alignment, and could be considered an important technology, for driving over long distances and curved routes, in the future. The sensing accuracy is from several centimetres to within twenty centimetres. + +Issues concerning this method are that accurate detection is not possible if there are other electromagnetic fields or objects which disturb or block electromagnetic fields near the driving position, and the electric magnetic field cannot reach the ground surface if the driving position is too deep. + +##### **I.4.5.3 Liquid pressure differential method** + +This method is used to accurately measure the depth of the driving position. The depth is detected by linking pressure sensors, which are inside the driving machine and above ground, with a hose filled with a liquid that has small bulk modules relative to temperature changes, and converting the pressure difference to a depth difference. These pressure sensors are extremely accurate and enable accurate detection to within several millimetres. + +Issues concerning this method are that air entering the hose, and differences in the temperature inside the driving machine and above ground, can easily produce error. However, this error can be reduced by constantly circulating the liquid inside the hose and by using temperature correction sensors. + +#### **I.4.6 Soil improvement methods** + +Construction is sometimes difficult to execute safely, or may affect the surrounding ground and structures, depending on the soil conditions. In these cases, an appropriate soil improvement method must be selected, taking into consideration soil conditions, the work environment and other factors, in order to stabilize the soil. + +##### **I.4.6.1 Groundwater level reduction method** + +If pits are located in places with a high groundwater level, water may flow into the pits or phenomena, such as boiling and heaving, may occur. In these cases, wells are dug near the pits to collect and drain away the water. Drainage methods include gravity drainage for highly permeable soil or vacuum drainage for soil which is not so permeable. + +Draining water for long periods may cause problems, such as ground subsidence or drying up surrounding wells, so sufficient surveys must be carried out in advance. + +##### **I.4.6.2 Chemical injection method** + +This is a general method for increasing soil strength and improving water-stopping performance. Liquid chemicals with coagulant properties are injected into soft soil, soil with a high groundwater level or other soil needing improvement, via injection pipes, to stabilize the soil and obtain water-stopping effects once the chemicals coagulate. + +The type of chemical, and the injection method used, may differ according to the applicable soil quality and permeability. + +#### **I.4.7 Jacking frames** + +Pipejacking and microtunnelling systems are often supplied with jacking frames as part of the purchased package. Frames are designed to provide the level of jacking pressure likely to be required by the shield being used on any given project. The requirements for the jacking frame on any project are determined by the ground conditions and the type of shield. + +#### **I.4.8 Shafts** + +As mentioned previously, almost all pipejacks and microtunnels are installed between a drive shaft and a reception shaft. The most notable exceptions are those where the exit point of the shield is directly out of the ground at a set position. Even then, a reception arrangement has to be designed in order to prevent environmental contamination by loss of lubricant or slurry, or to prevent the ingress of water into the pipeline. + +Drive shaft requirements vary greatly depending on the machine being used, ground conditions, pipe length and material, length of drive and type of installation. They may be round, rectangular or oval; sheet piled, segmentally lined, caisson constructed or even unsupported if ground conditions are good enough and local safety rules permit. + +The normal range of methods used for shaft sinking and construction is used also for pipejacking and microtunnelling, but one factor common to each drive shaft is that there has to be some form of reaction face for the jacking frame to push against. In suitable ground this can simply be the back wall of the shaft, but this is usually not the case and a thrust wall has to be provided. Normally of concrete construction, the thrust wall is an integral part of the shaft support and may be designed with a soft eye centre to allow the jacking frame to be rotated for a second bore in the opposite direction, or to allow a machine boring from another location to enter the shaft as a reception point. The thrust wall must enable the jacking frame to exert its maximum pushing force whilst maintaining the integrity of the shaft structure, and that of the surrounding ground, so as not to compromise the final pipeline structure. Requirements for shafts which are needed only for reception duties were mentioned earlier. + +Certain microtunnelling systems are designed for use with small drive shafts and techniques are available which allow the installation of 1.0 metre long pipes from a shaft of only 2.0 metres diameter. One such system is equipped with a cutter head and cone crusher, which moves with an eccentric radial motion, and can operate in a wide range of ground conditions including soil boulders up to 30% of the machine's outside diameter. + +#### **I.4.9 Pipes** + +Driving pipes are roughly divided into high and low strength pipes. High strength pipes include steel, reinforced concrete and other pipes which allow the driving force to be transmitted directly to the pipe. Low load resistance pipes include rigid PVC and other pipes which are unable to directly transmit the driving force. + +However, a wide range of pipe materials is available for installation using pipejacking and microtunnelling techniques, the choice depending on the requirements of the client, the ground conditions, transportation costs and the length of pipeline. Materials include reinforced and unreinforced concrete, polymer concrete (concrete aggregate within a matrix of resin), glass fibre/resin-based pipes, vitrified clayware (both glazed and unglazed), steel, ductile iron and also plastic. + +Probably the most important aspects of design, in respect of pipes for a pipejack project, are the allowable degree of joint deflection and the joint face geometry. In general, the deflection at the pipe joint face should not exceed $0.5^\circ$ although deflections of over $1.0^\circ$ may be permissible for curved drives using appropriate cushioning materials at pipe joints. The joint face should be manufactured to ensure squareness and must also be fitted with a suitable packer material to ensure the even distribution of the jacking force across the joint. It is important to be aware that, due to increases in point loading, the maximum permissible jacking load on a given pipe decreases significantly and quickly as the deflection at pipe joints increases. Maintaining as straight a drive as possible will allow the operator to take full advantage of the design loading of the pipe, should it be required. High deflection will reduce the maximum loading that the pipe string can withstand without fear of pipe failure in the ground. + +An essential feature of pipes for microtunnelling and pipejacking is that the joints do not extend outside the barrel of the pipe. In other words, the entire joint is contained within the normal pipe wall thickness, unlike conventional pipes for open-trench installation which usually have spigot and socket joints, with sockets of greater external diameter than the rest of the pipe barrel. For microtunnelling and pipejacking, the advantages of a low-friction external pipe surface without protrusions are obvious. + +Pipe length varies according to the microtunnelling system used, the pipe diameter and constraints of space. Typical lengths usually range from 1.0 and 2.0 metres, although lengths of 0.75 metres are available for small diameters. Much of the cost of microtunnelling pipe is in the joints, so the use of longer pipe lengths tends to save cost on pipes; on the other hand, this may require larger shafts. + +#### **I.4.10 Lubrication** + +The two greatest forces which need to be overcome in jacking a pipe are the weight of the pipe string and the friction between the surface of the pipe and the ground as the pipe moves through the bore. Friction increases with pipe diameter as a greater surface area of pipe is presented to the inertial surface of the bore. + +The problem of friction is most commonly addressed by using pipe of smallest acceptable diameter, and by lubrication. In the earliest days of pipejacking it was sometimes left to brute force to overcome the total resistance by simply installing a larger capacity jacking frame. This could lead to early pipe failures as the maximum load bearing capacity of the pipes was exceeded in difficult conditions. The introduction of lubrication using a bentonite mud or combination bentonite/polymer mixture can overcome most of the loading problems. The mud mixture is designed to work efficiently in the expected ground conditions. A simple formulation can be used where the lubricant will not be absorbed, or drain away, into the surrounding ground. In more difficult conditions, where loss of lubricant can be expected, or where ground pressures are likely to be high, the lubricant can be modified to reduce loss and to assist in providing ground support throughout the duration of the pipejack. + +The lubricant is conveyed by pipes installed within the main pipe string and is injected through ports drilled through the pipe wall. Each injection port is fed by a lubrication line. Injection is controlled either manually from the operator's station, or by means of a computer-monitored system through a central distribution manifold. The latter system is increasingly popular and allows measured amounts of specific lubricants to be added at the correct position, at an optimum pressure, along the pipe string as the ground varies and the pipe string moves forward. Computer monitoring often increases + +the efficiency of lubrication by minimizing over-lubrication at any one point, bearing in mind that lubricants can be expensive. On smaller diameter, often shallower, pipejacks or microtunnels this can be a significant advantage as it minimizes surface heave or loss of lubricant through cracks to the surface. + +On many projects, the use of the correct lubrication materials and techniques can bring about a considerable reduction in jacking loads and ground support problems. It may also allow the use of a smaller jacking frame, thus minimizing the size of the drive shaft and helping to reduce the overall cost of the project. Using modern lubricants and installation techniques, it may be possible to install up to 1000 metres of pipeline in a single drive. + +#### **I.4.11 Interjacks** + +Where the lubrication of a pipe may not be sufficient in itself to allow successful completion to the jacking operation (for example, where the length of the pipe string is such that its resistance to movement will exceed the capacity of a practical sized jacking frame, or where friction forces or ground movement factors will be difficult to overcome), another option should be considered before reducing the planned length of a pipejack: this option is the "interjack" station. + +The interjack station is a ring of hydraulic jacks within a steel framework which is inserted into the pipe string at strategic points. The interjack divides the pipe string into more manageable lengths. Each length, whether between jacking frame and interjack, interjack and interjack, or interjack and shield machine, can be advanced individually and independently from the rest of the pipe string. It is equivalent of having several smaller pipejacks in operation at the same time in the one bore, with each interjack using the pipe length behind it as its thrust wall. The use of interjacks reduces the potential for pipe failures since the maximum force on any individual "sub-string" depends on the number of pipe sections, plus the friction factor, over that length of pipe. Each interjack is controlled independently from the operator's station. + +#### **I.4.12 Jacking loads** + +The proper execution of a microtunnelling project depends on the proper selection of the method, workmanship of an appropriately skilled crew and limiting the unexpected by evaluating and scheduling the process. The ability to predict the jacking loads to an acceptable degree of accuracy can dramatically reduce unexpected problems. + +The jacking loads are the forces due to the friction between the external surface of the pipes and the ground (skin friction) and to the face pressure acting on the cutting head. + +The jacking loads affect some basic elements of the microtunnelling process: the strength of the pipe being jacked, the capacity of the jacking system to be used, the capacity of the shaft thrust wall to withstand the jacking force and the length of pipe to be installed in a single push. + +# ITU-T RECOMMENDATIONS SERIES + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of the ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching 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units** + +Recommendation ITU-T L.392 + +# ITU-T L-SERIES RECOMMENDATIONS + +## ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT + +| | | +|-------------------------------------------------------|--------------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node element (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +## Recommendation ITU-T L.392 + +# Disaster management for improving network resilience and recovery with movable and deployable information and communication technology (ICT) resource units + +## Summary + +Recommendation ITU-T L.392 introduces an approach for improving network resilience against disasters and to assist network recovery after disasters by physically mobilizing units and facilities that package movable and instantaneously deployable resources for information and communication technology (ICT). + +The movable and deployable ICT resource unit (MDRU) is a collection of ICT resources that are packaged as an identifiable physical unit, is movable by any of multiple transportation modalities, acts as a stand-in (substitute) for damaged network facilities, and reproduces and extends their functionalities. The MDRU also brings extra ICT resources to meet the great increase in communication demands expected in disaster areas. + +Focusing on the use of the units as a substitute for local nodes, this Recommendation reviews target objectives of disaster management and gives high-level requirements for both operations and facilities as a guideline. To shorten deployment time, which is the primary objective of network recovery with substitute, this Recommendation shows how to optimize the process that starts with equipment preparation in daily operation to service offering at the site of the disaster. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.392 | 2016-04-13 | 15 | 11.1002/1000/12837 | + +## Keywords + +Deployment process optimization, disaster management, disaster relief, MDRU, network resilience and recovery. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2016 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|------|----------------------------------------------------------------------------------------|----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 3.1 | Terms defined elsewhere ..... | 1 | +| 3.2 | Terms defined in this Recommendation..... | 1 | +| 4 | Abbreviations and acronyms ..... | 1 | +| 5 | Conventions ..... | 2 | +| 6 | Introduction..... | 2 | +| 7 | Usage scenarios of movable and deployable ICT resource units ..... | 3 | +| 7.1 | Factors underlying movable and deployable ICT resource unit usage scenarios ..... | 3 | +| 7.2 | Usage scenario of an movable and deployable ICT resource unit as a local node..... | 4 | +| 8 | Guidance to disaster management with the use of movable and deployable ICT units..... | 6 | +| 9 | Consideration on shortening the deployment process ..... | 7 | +| 9.1 | Outline of deployment process ..... | 7 | +| 9.2 | Process optimization..... | 7 | +| 10 | Security consideration ..... | 9 | +| | Appendix I – Information about movable and deployable ICT resource units..... | 10 | +| I.1 | Design principles for movable and deployable ICT resource units ..... | 10 | +| I.2 | General requirements for movable and deployable ICT resource units ..... | 10 | +| I.3 | Service-provisioning and network operation requirements..... | 17 | +| I.4 | Other open issues..... | 21 | +| | Appendix II – Disaster management with MDRU: Feasibility study in the Philippines..... | 22 | +| II.1 | Introduction ..... | 22 | +| II.2 | Summary of the ITU project..... | 22 | +| II.3 | Launching the feasibility study ..... | 24 | +| | Bibliography..... | 26 | + + + +# Recommendation ITU-T L.392 + +## Disaster management for improving network resilience and recovery with movable and deployable information and communication technology (ICT) resource units + +# 1 Scope + +This Recommendation describes an approach for improving network resilience and recovery by substituting healthy transportable and instantaneously deployable facilities for damaged ICT facilities; the substitutes are referred to as movable and deployable ICT resource units (MDRUs) throughout this Recommendation. + +After introducing the substitution approach to network resilience and recovery, this Recommendation identifies key factors for examining various MDRU usage scenarios, and introduces one promising MDRU use as a local node. Focusing on this use, this Recommendation reviews target objectives of disaster management and gives high-level requirements for both operations and facilities as a guideline. To shorten deployment time, which is the primary objective of network recovery, this Recommendation shows how to optimize the substitution process, starting with equipment preparation for daily operation to service offering at the site of the disaster. + +# 2 References + +None. + +# 3 Definitions + +### 3.1 Terms defined elsewhere + +None. + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following term: + +**3.2.1 movable and deployable ICT resource unit (MDRU):** A collection of information and communication resources that are packaged as an identifiable physical unit, movable by any of multiple transportation modalities, and which act as a stand-in (substitute) for damaged network facilities, and reproduce and extend their functionalities. + +NOTE – Packed into a container or box, an MDRU accommodates equipment for reproducing ICT services such as switches/routers, wired/wireless transmitters/receivers, servers, storage devices, power distribution unit, and air conditioners. + +## 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|----------------------------------------------| +| 3GPP | third Generation Partnership Project | +| AAA | Authentication, Authorization and Accounting | +| AP | Access Point | +| BS | Base Station | +| codec | coder-decoder | + +| | | +|--------|-------------------------------------------| +| DSP | Digital Signal Processor | +| EMC | ElectroMagnetic Compatibility | +| FWA | Fixed Wireless Access | +| HDD | Hard Disk Drive | +| HGW | Home GateWay | +| ICT | Information and Communication Technology | +| I/O | Input/Output | +| IP-PBX | Internet Protocol Private Branch exchange | +| LTE | Long-Term Evolution | +| MDRU | Movable and Deployable ICT Resource Unit | +| PC | Personal Computer | +| QoS | Quality of Service | +| SSD | Solid State Drive | +| TE | Terminal Equipment | +| UNI | User-to/-Network Interface | +| VM | Virtual Machine | +| VoIP | Voice over Internet Protocol | +| WAN | Wide Area Network | +| Wi-Fi | Wireless Fidelity | + +## 5 Conventions + +None. + +# 6 Introduction + +Network resilience and recovery against disasters can be tackled by multiple approaches. The primary approach is to strengthen networks in operation as much as possible and to minimize potential damage. This approach includes redundancy, backups and switch-over of the system or part of it. The secondary approach is to prepare transportable replacements that can stand in for the operational networks. When a disaster occurs and part of the network is destroyed, the prepared resources are deployed immediately to the damaged area. The substituted units replicate the role of the lost network facilities. This approach works well when a severe disaster occurs and network facilities, protected by the primary approach, are destroyed or rendered impossible to fix quickly. These two approaches complement each other, as movable-and-instantaneously deployable ICT resources are expected to work together with the remaining ICT facilities, until local networks in the damaged area are recovered. + +The movable and deployable ICT resource unit (MDRU) is expected to bring two benefits. + +- 1) Quick recovery of the capabilities lost to enable the communications needed for disaster relief activities in the area. +- 2) Quick deployment of extra ICT resources that will increase network capacity locally and thus minimize the impact of the great increase in communication demand usually carried by facilities outside the devastated area. This traffic spike can cause wide area failures of the network. + +As a consequence, movable-and-instantaneously deployable ICT resources enhance network resilience and recovery. + +To promote the secondary approach, the MDRU should be identified and specified. It should be physically movable by the widest possible range of transportation modalities, deployed and made operational in the minimum time, capable of replicating the lost network facilities, and compatible with the remaining facilities. To make the MDRU meet these requirements, standard specifications are essential. The physical form of the MDRU to meet transportation requirements, implementation guidelines and operational instructions for minimizing the time needed to make the MDRU ready, underlying universal ICT resources and service-creating capabilities that are built-in, and the way of connecting to the core network and surviving terminals are all standardization matters. Realizing compatible and easy-to-operate resource units allows the units to be treated as shared resources that can be used efficiently against many different disasters. Even when provided by other operators, organizations, or foreign countries, units that follow the common specification can be made fully operational as if they belonged to the operator. + +# **7 Usage scenarios of movable and deployable ICT resource units** + +Depending on disaster type and which parts of the network facilities survive the damage, there are many MDRU scenarios requiring different attributes, such as size and functionality. In this clause, the factors underlying MDRU usage scenarios are described first. Then, a promising MDRU application is introduced. Further information about transportable units is given in Appendix I. + +[b-ITU-TR, 2013] includes a number of case studies of the performance of public telecommunications systems in recent disasters along with a review of activities related to the use of telecommunications for disaster mitigation. + +## **7.1 Factors underlying movable and deployable ICT resource unit usage scenarios** + +The following factors should be taken into account when studying MDRU usage scenarios. + +- Disaster types, severity and timing – Disasters can be characterized from the viewpoints of spatial extent and timing. First, the size and uniformity of the damage vary with disaster type. Some disasters, such as tsunamis, tend to create areas of large uniform damage. Other types, such as earthquakes, can yield relatively lightly damaged areas, in which facilities may survive, interspersed with heavily damaged areas. The type of disaster also changes the temporal pattern of damage. The timing viewpoint includes whether the disaster has sufficiently long lead times to allow prediction and thus preparation, and whether the end of the disaster can be reliably predicted, thus allowing the start of recovery procedures at full power. Hurricanes and typhoons can be predicted in advance, while earthquakes are hard to predict and secondary earthquakes are common. +- Expected damage and surviving network facilities – As a consequence of the disaster type and severity, specific network facilities are likely to be destroyed, while other facilities may remain operational with high probability. Each network facility and portion should be examined to discover whether they are prone to being damaged according to the type of disaster. Even in the case of a tsunami, for example, some facilities such as optical fibres may remain undamaged because of their water-shielding. An earthquake damages surface facilities rather than those underground. Resource units should be designed to replicate the greatest possible range of facilities, so as to cover as many eventualities as possible. The network facilities and portions to be considered are links to core networks, local data centres and telephone switches, access networks, residential facilities, and terminals. + +NOTE 1 – Availability of electric power supply or local backup battery lifetimes should be considered when estimating surviving facilities. If backup batteries are working, the real problems may occur not just after the disaster but also several hours after it when the batteries are exhausted. + +NOTE 2 – Backups for public mobile networks (e.g., mobile switch centre, base stations and antennas) and their relationships with newly deployed MDRUs should be studied further. + +- Conditions and possible behaviour of users – whether users are safe, which actions they can take and which actions they are trying to take, should be considered to estimate required communication services needed and the level of demand. +- Service types to be considered – It may be hard to provide all services at the same time or to recover all services at the same pace after a severe disaster, due to resource limitations. Priority may need to be introduced so that critical services are recovered immediately in given resource limitations. +- Types of ICT resources to be deployed – Local tangible physical objects, such as the integrated resource unit packaged as a container or a box, temporary antennas for satellite communications or remote access to cloud services are ICT candidates for deployment. + +## **7.2 Usage scenario of an movable and deployable ICT resource unit as a local node** + +The MDRU, which simulates a local telephone switch and an edge node for Internet access, can be used to replicate a local network that has been destroyed. Figure 1 shows an example of an MDRU use case. + +![Figure 1: Example of MDRU use for network recovery. The diagram shows four stages: a) Example normal network, b) Destroyed network, c) Deployment of an MDRU, and d) Recovering network. A legend defines the acronyms: TE (Terminal equipment), PC (Personal computer), HGW (Home gateway), AP (Wireless Access point), BS (Base station for mobile terminals), and MDRU (Movable and deployable resource unit).](cfef993dcc8fb513de79eb1f93cf26ae_img.jpg) + +**Residential** + +Fixed TE (Phone) — HGW — Core network + +Fixed TE (PC) — HGW/ Wifi-AP — Core network + +Wifi-TE — HGW/ Wifi-AP — Core network + +**Outdoor** + +Wifi-TE — Wifi-AP — Local switch/ edge node — Core network + +Mobile TE — eNodeB/ BS — Local switch/ edge node — Core network + +Mobile TE — eNodeB/ BS — Local switch/ edge node — Core network + +**Legend:** +TE: Terminal equipment +PC: Personal computer +HGW: Home gateway +AP: (Wireless) Access point +BS: Base station (for mobile terminals) +MDRU: Movable and deployable resource unit + +**a) Example normal network** + +**Residential** + +Fixed TE (Phone) — HGW — Core network + +Fixed TE (PC) — HGW/ Wifi-AP — Core network + +Wifi-TE — HGW/ Wifi-AP — Core network + +**Outdoor** + +Wifi-TE — Wifi-AP — Local switch/ edge node — Core network + +Mobile TE — eNodeB/ BS — Local switch/ edge node — Core network + +Mobile TE — eNodeB/ BS — Local switch/ edge node — Core network + +**b) Destroyed network** +(Dotted boxes and lines imply failures) + +**Residential** + +Fixed TE (Phone) — HGW — Core network + +Fixed TE (PC) — HGW/ Wifi-AP — Core network + +Wifi-TE — HGW/ Wifi-AP — Core network + +**Outdoor** + +Wifi-TE — Wifi-AP — Local switch/ edge node — Core network + +Mobile TE — eNodeB/ BS — Local switch/ edge node — Core network + +Mobile TE — eNodeB/ BS — Local switch/ edge node — Core network + +**c) Deployment of an MDRU** + +**Residential** + +Fixed TE (Phone) — HGW — Satellite link — Core network + +Fixed TE (PC) — HGW/ Wifi-AP — Satellite link — Core network + +**Specific area** + +Wifi-TE survived — MDRU new — Local switch/ edge node — Core network + +Wifi-TE new — MDRU new — Local switch/ edge node — Core network + +Wifi-TE new — MDRU new — Local switch/ edge node — Core network + +Wifi-TE survived — MDRU new — Local switch/ edge node — Core network + +Wifi-AP — Local switch/ edge node — Core network + +**Outdoor** + +Mobile TE — eNodeB/ BS — Local switch/ edge node — Core network + +Mobile TE — eNodeB/ BS — Local switch/ edge node — Core network + +**d) Recovering network** + +**Residential - partly recovered** + +Fixed TE (Phone) — HGW — Core network + +Fixed TE (PC) — HGW/ Wifi-AP — Core network + +Wifi-TE survived — MDRU new — Local switch/ edge node — Core network + +Wifi-TE new — MDRU new — Local switch/ edge node — Core network + +Wifi-TE new — MDRU new — Local switch/ edge node — Core network + +Wifi-TE survived — MDRU new — Local switch/ edge node — Core network + +Wifi-AP — Local switch/ edge node — Core network + +**Outdoor** + +Mobile TE — eNodeB/ BS — Local switch/ edge node — Core network + +Mobile TE — eNodeB/ BS — Local switch/ edge node — Core network + +L.392(16)\_F01 + +Figure 1: Example of MDRU use for network recovery. The diagram shows four stages: a) Example normal network, b) Destroyed network, c) Deployment of an MDRU, and d) Recovering network. A legend defines the acronyms: TE (Terminal equipment), PC (Personal computer), HGW (Home gateway), AP (Wireless Access point), BS (Base station for mobile terminals), and MDRU (Movable and deployable resource unit). + +**Figure 1 – Example of MDRU use for network recovery** + +If a tsunami attacks a fibered area, local data centres and telephone switch offices may be totally destroyed, while the fibres remain viable. Some residential facilities, such as broadband routers [shown as home gateways (HGWs) in Figure 1] and smartphones [shown as mobile terminal equipment (TE) in Figure 1], may also survive. Just after the disaster and several days thereafter, local voice communications and the distribution of local community information are the most crucial + +services to be provided. In such a case, the MDRU that replicates the local data centre servers and telephone switches is most effective for recovering local communications in the devastated area. + +Figure 1 shows an MDRU use case and a recovery scenario for a destroyed local network. The scenario assumes that both residential and outdoor services are damaged due to a severe disaster as is shown in Figure 1 b). To provide urgent communication services over a particular area, an MDRU is deployed in the area and works as a local communication node [shown in Figure 1 c)]. The MDRU supports WiFi terminals both surviving and recent introductions. The MDRU shown provides a satellite link to access the core network. Long distance fibre is an alternative to access the core network. Users in the affected area download telephony applications from the MDRU and communicate with each other. It should be noted that access via satellite or a long distance fibre to the core network allows the MDRU to bypass the congested local switch, even if available or recovered, and thus offload traffic from the switch. + +The destroyed network is recovered step-by-step as is shown in Figure 1 d). Once the public local node becomes available, the MDRU will switch from the satellite link to the broadband access to the node and thus support higher-speed services and more terminals. + +It should be noted that Figure 1 shows the MDRU position from the overall network perspective. Terminals and access networks are modelled in an abstract way, and the actual access network technologies used, terminal capabilities and business relationships might alter the perspective. Viewed from the MDRU, whether and how to support specific equipment and relevant access networks needs further study. + +# **8 Guidance to disaster management with the use of movable and deployable ICT units** + +According to the factors and assumed use case in clause 7, network operation and facility management in preparation for disaster should recognize the following conditions as uncertain. + +### **Given conditions** + +- When a disaster occurs and how long it lasts. +- Where a disaster occurs and how large its impact could be. +- How severe is the damage caused by the disaster. +- How much additional or unusual demand the network should support. + +In addition, with movable and deployable ICT resources, network heterogeneity should be taken into account. + +Given the uncertainties above, the following objectives should be achieved for network recovery. + +### **Objectives for network recovery** + +- Rapidity. +- Transparency, or nearly so, of recovery to users. +- Prioritization of critical communications, if not all communications can be recovered; +- Smooth transition from an irregular and disaster-specific to regular and normal service offering. + +The following high-level requirements should be met to achieve the above objectives. + +### **Requirements on network operation with substitute ICT resources** + +- Grasp of the current and damaged situation. +- Actions while acknowledging the uncertainties. +- Mixed operation of heterogeneous facilities, some of which are used for a regular and normal service offering, while some are for an irregular and disaster-specific service offering. + +### Requirements on substitute ICT resources + +- Quick availability. +- Transportability. +- Robustness while being transported as well as operated. +- Multi-purpose design to meet unknown or changing demands. +- Support for some existing critical services in the face of extra and greatly increased demand. +- Support for disaster-specific services. +- Ability of operation by people who do not use facilities regularly. +- High connectivity with surviving facilities, while not harming them at all. +- Cost effectiveness with adoption of latest technologies. + +# 9 Consideration on shortening the deployment process + +## 9.1 Outline of deployment process + +The main objective of network recovery is to rapidly resume the ICT services that are suspended in a damaged area. With the use of the substitute ICT resources, the issue comes down to how quickly they can be prepared for work. To shorten the delay, the entire process associated with deployment of substitute ICT resources should be reviewed and reduced by optimization. This clause describes an enhanced deployment process suitable for MDRUs. + +Figure 2 shows an outline of the deployment process for MDRUs. The process starts with daily and regular preparation in the ordinary phase. After a disaster occurs, the process moves to preparation for restoration, which is specific to the disaster. This is followed by transportation of units and the installation of each unit at the disaster site. On site, service set-up starts when the installation of the ICT unit is completed and the unit becomes ready to use. Services recommence upon completion of service set-up. The process then shifts to service operation. The process then shifts to service operation. + +![Flowchart of the deployment process for MDRUs, showing phases from ordinary preparation to service operation.](ddc7460821484f1ae2835c67955c554c_img.jpg) + +The diagram illustrates the deployment process for MDRUs, structured into four main phases separated by key milestones: + +- Ordinary phase:** Includes the step **Regular preparation**. +- Milestone:** *Disaster occurrence* (separates Ordinary phase from Unit deployment phase). +- Unit deployment phase:** Includes the steps **Preparation for restoration** (highlighted in blue), **Transportation of units**, and **Installation of units**. +- Milestone:** *Units made ready* (separates Unit deployment phase from Service set-up phase). +- Service set-up phase:** Includes the step **Service set-up** (highlighted in yellow). +- Milestone:** *Start of service* (separates Service set-up phase from Operation phase). +- Operation phase:** Includes the step **Service operation**. + +A large downward-pointing arrow on the left indicates the sequence of steps. A smaller vertical double-headed arrow on the right highlights the transition between the Unit deployment phase and the Service set-up phase. The diagram is labeled L.392(16)\_F02. + +Flowchart of the deployment process for MDRUs, showing phases from ordinary preparation to service operation. + +**Figure 2 – Outline of process with movable and deployable ICT resource units** + +The duration of deployment, which extends from disaster occurrence to service operation, is determined by two main factors: unit delivery and service set-up, which are discussed in the following optimization stage. + +## 9.2 Process optimization + +Figure 3 shows optimization of the time taken to deploy MDRUs. + +### **Tasks in preparation for restoration and service set-up** + +Work in preparation for restoration, which is specific to and initiated just after the disaster, can be divided into three tasks: (1) system/network design; (2) procurement of physical resources; and (3) data preparation. The time taken is reduced by shifting some tasks to regular preparation. In other words, the ICT infrastructure needs to be prepared as much as possible before the disaster. + +Work for service set-up can be divided into four tasks: (4) interconnecting ICT units; users' devices and WAN; (5) system activation; (6) data installation; and (7) test. + +### **Three approaches for optimization** + +In the optimization, three approaches are taken to: + +- a) shift some tasks in the deployment and service set-up phases to the ordinary phase; +- b) automate some tasks; and +- c) perform some tasks concurrently. + +#### **Optimization** + +In approach a), the tasks shown in the middle of Figure 3 are rearranged so as to reduce the time needed for the deployment and service set-up phases. Tasks (1) to (4) and (6) are moved to the ordinary phase as much as possible. Specifically, typical deployment process patterns, which are flexible enough to support various disaster situations, are prepared beforehand and formalized as guidelines. When a disaster occurs, operators select one of the patterns to be applied to the case and follow the guideline. + +In approach b), several tasks in the service set-up phase are simplified or automated. To support user devices and to connect access networks around the unit, the unit can, for example, use WiFi instead of wired connections like optical fibres. The use of wireless technology for access network connection dramatically reduces the time needed to connect the user devices to the unit. In some advanced scenarios, WiFi access points are automatically configured to form a mesh network around the unit by broadcasting control signals from the unit to access points near the unit. To control the unit itself, the start-up process can be embedded in the unit's control software. Once an operator activates the unit remotely, the whole system automatically starts up according to the programmed sequence and becomes ready to use. + +In approach c), parallel processing is applied. Some independent tasks like physical wireless network configuration and service set-up are concurrently performed. Assume that user devices are registered with the unit [working as an internet protocol private branch exchange (IP-PBX)] when they first attempt to access the service. The registration performs both data installation and tests for the interconnection of the user device to the unit. The customer database is therefore generated concurrently with service operation, so initial data installation is minimized and simplified. + +![Diagram comparing Traditional process (not optimized) and Optimized process for movable and deployable ICT resource units. The traditional process is a linear flow of seven steps: (1) Design (system, network), (2) Procurement of resources, (3) Data preparation, (4) Interconnection, (5) System activation, (6) Data installation, and (7) Test. These steps are grouped into four phases: Ordinary phase (steps 1-3), Unit deployment phase (steps 4-5), Service set-up phase (step 6), and Operation phase (step 7). The optimized process shows a significant reduction in time, with steps (1), (2), and (3) being completed much faster, and steps (4), (5), and (6) being completed even faster, leading to a rapid service offering. The optimized process is represented by a single yellow box, indicating a much shorter duration than the traditional process.](33ed1f9b27c7c21c797aa928b0f06851_img.jpg) + +The diagram illustrates the optimization of a process for movable and deployable ICT resource units. It is divided into two main columns: **Traditional process (not optimized)** and **Optimized process**. + +**Traditional process (not optimized):** This column shows a sequential flow of seven steps, each in a separate box, grouped into four phases: + +- Ordinary phase:** (1) Design (system, network), (2) Procurement of resources, (3) Data preparation. +- Unit deployment phase:** (4) Interconnection, (5) System activation. +- Service set-up phase:** (6) Data installation. +- Operation phase:** (7) Test. + +**Optimized process:** This column shows a much faster process. The first three steps (1, 2, 3) are grouped into a single, very short duration. The next three steps (4, 5, 6) are also grouped into a single, very short duration, represented by a yellow box. The final step (7) remains as a separate box. Blue arrows indicate the flow from the traditional process to the optimized process, showing a significant reduction in time for the first six steps. + +L.392(16)\_F03 + +Diagram comparing Traditional process (not optimized) and Optimized process for movable and deployable ICT resource units. The traditional process is a linear flow of seven steps: (1) Design (system, network), (2) Procurement of resources, (3) Data preparation, (4) Interconnection, (5) System activation, (6) Data installation, and (7) Test. These steps are grouped into four phases: Ordinary phase (steps 1-3), Unit deployment phase (steps 4-5), Service set-up phase (step 6), and Operation phase (step 7). The optimized process shows a significant reduction in time, with steps (1), (2), and (3) being completed much faster, and steps (4), (5), and (6) being completed even faster, leading to a rapid service offering. The optimized process is represented by a single yellow box, indicating a much shorter duration than the traditional process. + +**Figure 3 – Optimization of process for movable and deployable ICT resource units** + +# 10 Security consideration + +To combat the consequences of severe natural disasters and provide the rapid network and service recovery needed, security criteria that are different from those in normal operation may be applied. Careful consideration is necessary. + +In this Recommendation, the following descriptions are relevant to security considerations. + +- The MDRU is assumed to be connected to the public network via the user-to-network interface (UNI), which provides secure connection from the public network perspective. +- It is recommended that the MDRU support flexible authentication, authorization and accounting (AAA) management, some of which allows light AAA management and rapid service offering. + +# Appendix I + +## Information about movable and deployable ICT resource units + +(This appendix does not form an integral part of this Recommendation.) + +This appendix gives help in understanding the profile of MDRUs by an example of realization and possible requirements or requirement categories. + +### I.1 Design principles for movable and deployable ICT resource units + +The following principles are to be recognized when MDRUs are designed and related standards are discussed. + +Disasters create a network situation where the resources are unknown, heterogeneous, and quite limited. To cope with such situations, MDRUs should be designed to: + +- provide bare minimum connectivity via the essential parts of the standards; +- achieve fluidity and mobility of node functionality to substitute for function-rich network nodes, which need a very long time to recover; +- offer easy, rapid and automated configuration to shorten the time to service delivery; +- be adaptable and dynamic for control and operation to maximize the use of limited available resources; +- support security and privacy to restore the original complex ICT environment as much as possible. + +### I.2 General requirements for movable and deployable ICT resource units + +This Recommendation focuses on container-type MDRUs that simulate data centre servers and local office switches. This clause describes the top-level requirements to be met to allow common and wide use of the MDRU. Figure I.1 shows general MDRU requirements, which are described in clauses I.2.2 to I.2.6. + +NOTE – Other MDRU types, such as van-type vehicles, need further study. [b-Sakano, 2015] + +![Diagram of a Movable and Deployable Resource Unit (MDRU) showing its general requirements.](96b0240f56d14453b5da05ec30fd5c6e_img.jpg) + +The diagram illustrates a Movable and Deployable Resource Unit (MDRU) as a blue-outlined container. Inside the container, there are three blue rectangular blocks representing internal components. Three callout boxes with arrows pointing to specific parts of the MDRU describe key requirements: + +- External physical appearance (e.g., shape, size, and weight)**: An arrow points from this box to the top edge of the MDRU container. +- Performance of the unit (e.g., networking, I/O, computing, and storage)**: An arrow points from this box to the internal components. +- External interfaces (e.g., network interfaces and power supply)**: An arrow points from this box to the bottom edge of the MDRU container. + +The label "MDRU" is placed inside the container. The diagram is identified by the code "L.392(16)\_FI.1" in the bottom right corner. + +Diagram of a Movable and Deployable Resource Unit (MDRU) showing its general requirements. + +Figure I.1 – General movable and deployable ICT resource unit requirements + +#### I.2.1 Example of implementation + +Figure I.2 to Figure I.6 illustrate an example of MDRU implementation. Figure I.7 shows another MDRU implementation, i.e., installation in a van-type vehicle. + +![A blue and white flatbed truck transporting a large white MDRU unit on a road.](93afce28d7dec5b2202789b31b4ef8ab_img.jpg) + +A blue and white flatbed truck is shown from a high angle, driving on an asphalt road. On its flatbed, it carries a large, white, rectangular container-like unit (MDRU) with blue horizontal stripes. The truck cab is blue with a white roof and features the word 'Zest' and a crane arm. The license plate reads '28-71'. The surrounding environment consists of green vegetation and a grey road surface. + +A blue and white flatbed truck transporting a large white MDRU unit on a road. + +**Figure I.2 – Transporting a movable and deployable ICT resource unit to a remote site** + +![Two workers in white uniforms and yellow hard hats setting up a white MDRU unit on a paved area.](41245ac07db266bea228735b9e8c8b73_img.jpg) + +The image shows a white MDRU unit placed on a blue protective sheet on a paved ground in front of a brick building. Two workers wearing white jumpsuits and yellow hard hats are working on the unit; one is climbing a silver A-frame ladder leaning against the side, and the other is on top of the unit. The unit has 'MDRU' printed on its side along with blue graphic stripes and several logos at the bottom. Various equipment and bags are visible on the ground nearby. + +Two workers in white uniforms and yellow hard hats setting up a white MDRU unit on a paved area. + +**Figure I.3 – Deploying and configuring a movable and deployable ICT resource unit at a remote site** + +![A white, box-like ICT resource unit with its front panel open, revealing internal server racks and networking equipment. The unit is situated outdoors on a paved area next to a brick building. The open door shows various cables and components inside.](fbfaa723129f8b8e3be651c6fe7cfab7_img.jpg) + +A white, box-like ICT resource unit with its front panel open, revealing internal server racks and networking equipment. The unit is situated outdoors on a paved area next to a brick building. The open door shows various cables and components inside. + +A white, box-like ICT resource unit with its front panel open, revealing internal server racks and networking equipment. The unit is situated outdoors on a paved area next to a brick building. The open door shows various cables and components inside. + +**Figure I.4 – Opening the front panel of a movable and deployable ICT resource unit** + +![A person sitting inside the open ICT resource unit, working on a laptop. The interior is filled with server racks, networking equipment, and various cables. The unit is situated outdoors on a paved area next to a brick building.](97fe9069356cc2a84e8e70673e405958_img.jpg) + +A person sitting inside the open ICT resource unit, working on a laptop. The interior is filled with server racks, networking equipment, and various cables. The unit is situated outdoors on a paved area next to a brick building. + +A person sitting inside the open ICT resource unit, working on a laptop. The interior is filled with server racks, networking equipment, and various cables. The unit is situated outdoors on a paved area next to a brick building. + +**Figure I.5 – System configuration and start-up of a movable and deployable ICT resource unit** + +![Interior view of a movable and deployable ICT resource unit showing server racks and networking equipment.](3267a096e9ca525744d8cd820f12eb59_img.jpg) + +A photograph showing the interior of a white container that has been converted into an ICT resource unit. The container's doors are wide open, revealing two black server racks. The left rack contains various electronic components, while the right rack is filled with networking switches and routers connected by a tangle of blue Ethernet cables. The floor is a light green color, and the overall space is organized for technical equipment. + +Interior view of a movable and deployable ICT resource unit showing server racks and networking equipment. + +**Figure I.6 – Components inside a movable and deployable ICT resource unit** + +![Exterior view of a white van with blue stripes and 'MDRU' branding, identified as a movable and deployable ICT resource unit.](1630bfd9ebf9b95faec11ae6cdfd9c0a_img.jpg) + +A photograph of a white van parked on a green-painted asphalt surface under a clear blue sky. The van features a prominent blue stripe along its side with the letters "MDRU" in large white font. Below this, in smaller text, it reads "Movable & Deployable ICT Resource Unit". The roof of the van is equipped with a white rack holding several antennas and other communication equipment. Other white vans are visible in the background. + +Exterior view of a white van with blue stripes and 'MDRU' branding, identified as a movable and deployable ICT resource unit. + +**Figure I.7 – A van-type movable and deployable ICT resource unit** + +As shown in Figure I.8, the MDRU is normally installed near the disaster response centre or a shelter to enable construction of a wireless access network. In addition, fixed wireless access (FWA) systems can be set up to allow communication with remote shelters. + +![Diagram illustrating communication between shelters via a movable and deployable ICT resource unit (MDRU).](b6671cfafda3820aafe9a24fa7a4d8c7_img.jpg) + +This diagram shows a network of communication. On the left, two shelters, 'Shelter A' and 'Shelter B', are each connected to a 'Fixed wireless access (FWA)' unit. These FWA units are connected via dashed orange lines to a central 'Disaster response centre (City Hall)'. A blue curved arrow indicates a connection from a helicopter carrying an 'MDRU' to Shelter A. Another blue curved arrow shows a connection from the City Hall to a van labeled 'MDRU'. This van is connected to a 'Wifi' network, which is further connected to several user devices including laptops, tablets, and smartphones. The text 'L.392(16)\_FI.8' is located in the bottom right corner. + +Diagram illustrating communication between shelters via a movable and deployable ICT resource unit (MDRU). + +**Figure I.8 – Communication between shelters via a movable and deployable ICT resource unit** + +In certain conditions, it may be difficult to bring even a small vehicle-type MDRU into the disaster zone. In such a case, a briefcase-type MDRU, which is made easier to transport by limiting its capabilities, can be brought in to provide a limited range of information and communication services. Figure I.9 shows a case where a briefcase-type MDRU provides only a telephone service. + +By selecting an appropriate type of MDRU, it is possible to provide as many information and communication services as possible in a disaster-stricken area, depending on the conditions in the area. + +![Diagram of a briefcase-type movable and deployable ICT resource unit.](523ab7b925beb555f88b2e1e1336974f_img.jpg) + +This diagram shows the components of a briefcase-type MDRU. At the center is an open black briefcase containing a 'Small size phone system' (a red device held in a hand) and a 'VoIP adaptor for analogue line' (a white rectangular device). To the left of the briefcase are a 'Battery' (a black rectangular device) and the 'VoIP adaptor for analogue line'. To the right are the 'Small size phone system' and an 'Access point for Wifi based access network' (a white square device). Below the briefcase is a row of 'User devices like smartphones and IP-based devices', including a smartphone, a feature phone, a tablet, a laptop, and another smartphone. Below the briefcase, the text 'Specification (example)' lists 'Dimension: 410 mm × 310 × 100 mm' and 'Weight: 2.0 kg'. The text 'L.392(16)\_FI.9' is in the bottom right corner. + +Diagram of a briefcase-type movable and deployable ICT resource unit. + +**Figure I.9 – Briefcase-type movable and deployable ICT resource unit** + +#### I.2.2 External physical appearance + +The most fundamental requirement of an MDRU is its ability to be conveyed by ordinary transportation. To meet this requirement, the basic physical appearance should be specified. + +The MDRU is required to comply with physical appearance standards as follows. + +Basic physical parameters: + +- shape, size, and weight; + +NOTE 1 – Long antennas hinder transportation. They should be dismantled and assembled when installed. The extendible antenna is another solution to easy transportation. + +when carried: + +- tolerance against transportation stress (e.g., degree of tilt and shock loads); +- capabilities that remain operational even when carried; + +NOTE 2 – To reduce system set-up time, some capabilities should remain in the hot state even while the unit is being transported. + +After installation: + +- electric power to be supplied or battery capacity if it is equipped with the unit; +- electromagnetic compatibility (EMC) requirements to be met; +- tolerance with respect to temperature and humidity; and +- conditions in operation such as indoor or outdoor. + +#### **I.2.3 External interfaces** + +To connect with network facilities toward the core network and to accommodate surviving access networks and terminals, interfaces to support the two should be specified. + +The MDRU is required to support specified external interfaces to connect with network facilities towards the core network and to accommodate surviving access networks and terminals. The specification should cover physical to logical interfaces on each layer. + +NOTE – As for physical implementation, radio and fixed cable interfaces should be considered. + +#### **I.2.4 External logical appearances** + +It is crucial to mobilize sufficient ICT resources (provided by MDRUs) and sufficient service capabilities over the resources to satisfy the requirements of a devastated area. To treat multiple MDRUs in the same manner without concern for machine-specific or manufacturer-specific settings, parameters associated with the MDRU should be the same. + +The MDRU is required to express its logical appearance, which should characterize the fundamental capabilities of the MDRU, its quantitative capacity and related performance. Standard specifications should provide a set (or a limited number of sets) of reference parameters and target values. + +The MDRU reference parameters should, at least, characterize the following fundamental capabilities: + +- supported input and output (I/O) interfaces (in terms of physical medium type, their speed, and the number of ports); +- networking (with regard to address space capacity for dynamic allocation, registration, routing and switching throughput, and the number of end terminals supported); +- computing capacity (usually indicated in the number of the reference processors); +- storage [the size of available memory on board and on hard disk drive (HDD) or solid state drive (SSD)]. + +#### **I.2.5 Preferred setting of a movable and deployable ICT resource unit** + +To encourage the introduction of MDRUs into particular disaster scenarios or damaged areas, some typical settings of the capabilities and performances of the MDRU may be specified as useful references. + +The following are initial considerations for those reference settings. + +- Standalone or building block type. + +NOTE – A building block-type MDRU assumes its use in combination with other units that interact with each other and provide higher performance in total. + +- Super light type. +- Switching-intensive, interface-rich, processor-intensive, or memory-rich type. +- Ultra power saving type. +- High- or low-temperature tolerant type. +- Types intended for rural or urban areas. + +#### **I.2.6 Consideration of movable and deployable ICT resource unit size** + +As discussed in clause I.2.1, there is a variety of MDRU implementations ranging from a train-transporting container to a compact easy-to-carry briefcase. Although components inside MDRUs are supposed to be modules, which should allow any of them to be used in combination and meet any package size, larger-size implementations have some scale merit. They can provide larger capacity and full functionality by themselves. Smaller-size implementations can answer high mobility, which is hard to achieve with large and heavy boxes. + +This clause gives consideration of how an MDRU is designed, selected and prepared. + +- **Transportability:** Weight and size are the dominant factors for being transportable. Speed to transport and time to recovery determine the effectiveness of MDRUs. Standards of transportation means (train containers, helicopters and military transport, and ordinary cars) should be considered when choosing size and weight. +- **Geographic area to cover and time to deployment:** Depending on the area to be covered and duration to use, MDRU size varies. In some case, MDRUs will be (semi-) permanently used. For such a long-term use, larger (i.e., capacity-rich and function-rich) and more tolerant implementations, which are hard to achieve by the combination of handy implementations, are preferable. +- **Reachability from the core network:** As is seen in the cloud, many services can be provided from a remote cloud if a broadband path is available to the MDRU. Otherwise, local site resources and capabilities brought by MDRUs need to be rich and larger size is preferable. + +Figure I.10 shows a possible menu of MDRU implementations in terms of resource capacity and mobility. + +New criteria and parameters for designing appropriate MDRUs are discussed in clause I.3.2.8. + +![Figure I.10: A menu of movable and deployable ICT resource units. The diagram shows four types of units arranged along a diagonal from top-left to bottom-right. The vertical axis is labeled 'Resource capacity' with 'Large' at the top and 'Small' at the bottom. The horizontal axis is labeled 'Mobility' with 'Low' on the left and 'High' on the right. The units are: 'Train-container type' (top-left, large capacity, low mobility), 'Truck-container type' (middle-left, medium capacity, low mobility), 'Van type' (middle-right, medium capacity, high mobility), and 'Briefcase type' (bottom-right, small capacity, high mobility). Red arrows indicate the trend of increasing mobility and decreasing capacity from top-left to bottom-right. A small code 'L.392(16)_FI.10' is in the bottom right corner.](0f79a59f3766fc341ff688a23692c1d9_img.jpg) + +Figure I.10: A menu of movable and deployable ICT resource units. The diagram shows four types of units arranged along a diagonal from top-left to bottom-right. The vertical axis is labeled 'Resource capacity' with 'Large' at the top and 'Small' at the bottom. The horizontal axis is labeled 'Mobility' with 'Low' on the left and 'High' on the right. The units are: 'Train-container type' (top-left, large capacity, low mobility), 'Truck-container type' (middle-left, medium capacity, low mobility), 'Van type' (middle-right, medium capacity, high mobility), and 'Briefcase type' (bottom-right, small capacity, high mobility). Red arrows indicate the trend of increasing mobility and decreasing capacity from top-left to bottom-right. A small code 'L.392(16)\_FI.10' is in the bottom right corner. + +**Figure I.10 – A menu of movable and deployable ICT resource units** + +### I.3 Service-provisioning and network operation requirements + +Following the top-level requirements above, the next level requirements refer to the service-specific aspects and the network operation aspects. + +#### I.3.1 Service-specific requirements provided for users + +Depending on the type of disaster and requirements in the devastated area, particular services are targets for recovery. + +##### I.3.1.1 Telephony and related services + +The real-time communication service, which includes voice and video telephony, reflects the existence and activity of the communicator. The service is considered essential for reassuring people that their family and friends are safe and sound. The service is also useful for supporting the assured and stable work environment necessary for rescue operations. + +The MDRU is required to support the real-time communication service. The following are included in the service: + +- ordinary voice calls; +- complementary services such as multi-party calls, text messaging, presence, and voice mail; +- access to and download of the application that provides the services above. + +In support of the above services, the MDRU is required to support the followings capabilities: + +- identification of terminals or users (i.e., numbering, naming and addressing); + +NOTE 1 – In some case where the MDRU is to be operated without any interaction with public networks, the original numbers associated with the subscribing operator may not be available. Alternative identification, authentication and authorization schemes should be considered. + +- registration of terminals or users; + +NOTE 2 – If simpler operation is required, AAA for terminals or users may not be necessary. Logging of use may compensate for AAA. + +- connection/session set-up, release, and management; + +NOTE 3 – The connection and session includes calls between one terminal in the damaged area and one in an undamaged area. Traversing networks and gateways involved in the calls should be + +considered. The networks include the network established by the MDRU and other public undamaged networks beyond its control. To locate and operate the gateways properly is another issue for network planning. The consideration should cover both incoming and outgoing calls to and from the damaged area. + +NOTE 4 – In the case of a large-scale disaster, multiple MDRUs may be installed, each of them supporting a particular area independently. Some of the MDRUs may become interconnected or disconnected. Some of them may be connected to the core network or disconnected. Depending on the disaster and resultant damage, the interconnections may be intermittent. Scenarios and required capabilities need further study; + +- congestion avoidance and prioritized call handling; +- adequate security and privacy. + +One example of implementation is the operation of the MDRU as an IP-PBX, which tentatively accommodates smartphone users via the voice over internet protocol (VoIP) application. Terminals outside the disaster area identify the IP-PBX as a dedicated number and the terminals under MDRU control are identified with the dedicated number as a prefix. The terminals directly accommodated by the IP-PBX are reachable by local (original) numbers, while they are reached by two-step dialling from outside the disaster area [b-Kotabe, 2015]. + +##### **I.3.1.2 Data centre services** + +If network facilities associated with Internet access are destroyed, all Internet services will be stopped in a certain area. To cope with this situation, the MDRU is expected to offer alternative Internet access by providing temporary communication channels (e.g., via satellite). If the temporary channel is limited or impossible, it is also expected that the MDRU works as an independent local data centre and provides Internet-type services by itself to local users. The following are tentative requirements in support of this scenario. + +The MDRU is required to provide alternative routes for Internet access to handle cases where original Internet access has been dropped. + +The MDRU is required to provide a virtual machine (VM) and web applications running on the VM. + +The MDRU is required to support web-based information services and related database management by itself, even if Internet access is not available. + +It is recommended that the MDRU support migration of local web-based services and related database management to the Internet service when Internet access becomes available. + +##### **I.3.1.3 Services for early warning and disaster relief** + +[b-FG-DR, 2014] describes: 1) alarm services for imminent disasters as early warnings; and 2) services to support people in the devastated area as disaster relief. Further investigation is necessary to support these identified services by the MDRU. + +Other services and applications for disaster relief are described in [b-ITU-T E.108]. + +Example services to be studied are as follows. + +- Information distribution from authority to ordinary citizens in the damaged area (one-to-many multicasting or broadcasting). +- Directory of afflicted people in the damaged area: instead of collecting papers and using message boards, database creation about people in the area is the very first task to be done. The task includes user ID allocation, profile registration and maintenance. +- Local information sharing inside the damaged area (information upload and retrieval or event notification service with or without subscription). +- Information publication from the damaged area to undamaged areas. +- Other information services. + +#### **I.3.2 Network operation requirements** + +The following are the requirements of MDRU operators. + +##### **I.3.2.1 Agile deployment and installation through all processes and operations** + +The MDRU is required to be deployed and installed in an agile manner. The requirement should cover all processes of operations. + +- Time reduction in the planning phase: Planning the use of MDRUs and their preparation including procurement should be shortened. Reference manuals for MDRU preparation may be useful. +- Time reduction for the system configuration phase: Schemes and technologies should be investigated that divide the conventional interrelated configuration processes into independent ones and thus allow parallel processing to reduce configuration time. This may involve simple process examination and re-arrangement. It also includes separating the interrelated processes, which are to be treated in a sequential manner, into independent ones by resource abstraction technologies. +- System configuration in the transport phase: It is recommended that MDRUs be configured before the system is deployed and installed in the target area, even while it is being transported. The configuration process should be re-organized so as to minimize the processes needed after installation at the damaged area. To improve system stability for in-transport processing, more robust devices, such as solid state drives (SSDs), should be considered, rather than hard disk drives (HDDs). +- Mobility and fluidity of applications: To shorten the application installation time and continue the service with minimum interruption, cloud-computing live migration of the MDRU resources should be investigated. It should be noted that this is valid only when the MDRU is connected to the core network and the cloud service is available through the core network. + +##### **I.3.2.2 Local switch and access server replication** + +The MDRU is required to replicate the functionalities of main node functions, such as telephony switches, access servers to the Internet, and ICT servers. + +The MDRU is required to provide intensive ICT resources; these will be needed to meet the greatly increased demands raised by post-disaster communications. + +The MDRU is required to operate as a user facility from the public commercial network viewpoint and to be connected to the public commercial networks via their UNI interface. This provides the MDRU with stronger connectivity without regard to operator-specific restrictions and thus enables quick replication. The UNI connection is also favourable for the public networks to secure the network. + +The MDRU is required to work in a standalone fashion, and so should not mandate any connection to the public network while providing local services by itself. + +The MDRU is also required to work with the functionalities in the core networks, when they are available, in a cohesive manner. + +##### **I.3.2.3 Access network recovery** + +Recovery of access networks in the damaged area is one of the critical tasks. + +The MDRU should make maximum use of surviving access network facilities, as available, to recover user and terminal reachability. + +Remaining access and user network facilities may be used more efficiently with a slight configuration change. One example is to reconfigure surviving residential WiFi access points so as to connect with + +each other and build a transient local network as a new operation mode. Several technical issues have been identified, namely: the nature of the trigger to change the operation mode of WiFi access points, how the trigger should be given, how the local network should be created and how packets should be forwarded through the resulting network [b-Shimizu, 2015]. + +##### **I.3.2.4 Mobile terminal support** + +Thanks to advanced terminal capabilities and strong demands for their use for public safety, including disaster recovery operations, direct communications and group communications among some long-term evolution (LTE) terminals are under consideration in the third generation partnership project (3GPP) release 12 and onward. + +The MDRU may work well with those terminals by providing local database and information processing to offset the lack of core network connectivity. Support of those advanced mobile terminals by the MDRU is for further study. + +##### **I.3.2.5 High-speed transport (up to 100 Gbit/s) over unknown fibres** + +In some disasters, fibre remains available even though termination devices are damaged. An intelligent fibre-termination device that accommodates unknown fibres, adjusts its characteristics to the fibres automatically and provides the maximum throughput is another technical challenge. Recent digital signal processors (DSPs) applied to optical signal processing allow fine tuning and make the adjustment possible. + +##### **I.3.2.6 Media processing enhancement** + +To make maximum use of limited resources (such as storage and bandwidth), contents of communication sessions may be further compressed while maintaining the minimum level of meaning. Enhanced media processing, i.e., changing the codec of the same media type or changing the media type itself while maintaining the meaning of the contents can be useful. + +After a disaster, normal user procedures that rely on the traditional method may be damaged or not work properly. For example, users may lose their mobile phones and thus their stored number directories; few people have memorized the numbers of their relatives. For elderly people who still rely on fixed phones, they are not reachable if the phone is lost. Voice and face recognition to eliminate the need for relying on telephone numbers may be helpful for identifying users and their messages. + +Just after a disaster, network configurations become too complicated to operate in the normal way. To save time and resources, some service may be offered without precise accounting of their use. Only overall records of use may be stored for later detailed analysis. Enhanced log analysis may be necessary. + +Complicated and unstable network configurations may create problems that are hard to diagnose in the normal way. It would be useful to identify what type of network information is the best indicator of abnormality. Collection and analysis of the large volume of data is another challenge in the media processing domain. + +The following are candidate areas for media processing enhancement for the MDRU: + +- media codec or type change to suit the limited resources available and to economize on their use (such as storage and transmission bandwidth); +- voice and video recognition for user identification and communication support; +- usage log analysis; +- fault notification collection and their analysis for fault management. + +##### **I.3.2.7 New network quality of service and performance criteria allowing for heterogeneous network operation** + +The situations necessitating MDRU deployment are quite different from those of normal network operations. Quality of service (QoS) and performance requirements of the so-called heterogeneous network consisting of public networks and MDRUs may be different from the normal homogeneous situation. By introducing a new set of criteria for them, the operator can run the heterogeneous network in a flexible manner. + +Some QoS and performance objectives (e.g., for voice calls) need to be maintained for the heterogeneous network; some may be stricter (e.g., emergency services), while others can be degraded (e.g., video entertainment). + +##### **I.3.2.8 New criteria and parameters for designing appropriate MDRUs** + +There can be different types of MDRUs, e.g., in terms of size. A criterion for showing the effectiveness of each type may be useful. A guideline based on the new criteria would be helpful in estimating the appropriate number of units and their capacities against the expected damage caused by disasters. Consideration of MDRU size is given in clause I.2.6. + +### **I.4 Other open issues** + +This clause briefly lists the issues related to MDRUs. + +- Cost consideration – even against severe disasters, we are unable to make unlimited investments for backup facilities such as MDRUs. Reasonable cost calculation methods to justify the investment are necessary. +- Life cycle consideration – Similar to other network products, the MDRU should use the latest technologies. Different from others, the MDRU may have a longer time span, which may need longer term product maintenance. Maintenance for long-life-cycle products should be considered ranging from individual devices for repair to maintenance engineer skills. + +# Appendix II + +## Disaster management with MDRU: Feasibility study in the Philippines + +(This appendix does not form an integral part of this Recommendation.) + +### II.1 Introduction + +The islands of the Philippines lie in the typhoon corridor of the Pacific region and experience an average of 20 typhoons per year. Typhoon-fed storms and high water are the most critical problems for the Philippine government and its residents. In November 2013, the Visayas region of the Philippines felt the full force of super typhoon Haiyan. Typhoon-fed storm surges grew to several metres high along the sea coast and caused widespread devastation in the area, similar to that of a tsunami. To make matters worse, the communication blackout obstructed attempts to evacuate people. 6 300 people lost their lives in the typhoon, and the numbers of missing and injured people are 1 061 and 28 689 [b-NDRRMC]. + +National disasters are on the rise, and thus, the United Nations and the international community are continuing efforts to find ways to reduce the risk of natural disasters, prevent the loss of lives, and reduce economic losses. In the process, the Government of Japan and ITU are collaborating to provide assistance to restore telecommunication connectivity in one of the islands most affected by typhoon Haiyan. On 13 May 2014, the Ministry of Internal Affairs and Communications (MIC) in Japan, the Department of Science and Technology (DOST) in the Philippines and ITU finalized a co-operation agreement for a feasibility study on restoring connectivity through the use of the MDRU and launched the project. + +### II.2 Summary of the ITU project + +The ITU project, entitled Feasibility study of restoring connectivity through the use of the movable and deployable ICT resource unit, was inaugurated in May 2014 with the objectives of studying the effectiveness of the MDRU in providing immediate communications infrastructure and IT (information technology) facilities in the worst disaster-stricken areas in Cebu, Philippines, and in studying the viability of the MDRU as a communication solution in the aftermath of a disaster. San Remigio municipality on Cebu Island was the location of the MDRU feasibility study. The municipality consists of 27 barangays, or districts, and has a population of about 64 000. Onsite reports of the disaster were gathered manually because all communication networks had been destroyed (Figure II.1). The only source of communication to the government was through a satellite phone from the office of the mayor. + +![Figure II.1: Location of San Remigio municipality in the Philippines and depiction of wireless network in San Remigio before the typhoon. The figure consists of two parts. The left part is a map of the Philippines with a red circle highlighting the location of San Remigio on the island of Cebu. An orange arrow points from this circle to the right part of the figure. The right part is a satellite image of San Remigio showing a wireless network infrastructure. Labels include 'Barangay 1', 'Barangay 2', 'Municipal Building', 'SU 1', 'SU 2', 'PTP 1', 'PTP 2', 'Bagtic', 'PTP 3', 'AU 1', 'Bankasan', and 'San Miguel'. The network was destroyed by the typhoon.](6a73c2b5fcbc3ec5ab9cc694467a9da6_img.jpg) + +Figure II.1: Location of San Remigio municipality in the Philippines and depiction of wireless network in San Remigio before the typhoon. The figure consists of two parts. The left part is a map of the Philippines with a red circle highlighting the location of San Remigio on the island of Cebu. An orange arrow points from this circle to the right part of the figure. The right part is a satellite image of San Remigio showing a wireless network infrastructure. Labels include 'Barangay 1', 'Barangay 2', 'Municipal Building', 'SU 1', 'SU 2', 'PTP 1', 'PTP 2', 'Bagtic', 'PTP 3', 'AU 1', 'Bankasan', and 'San Miguel'. The network was destroyed by the typhoon. + +**Figure II.1 – Location of San Remigio municipality in the Philippines and depiction of wireless network in San Remigio before the typhoon. +(The network was destroyed by the typhoon.)** + +A summary of the feasibility study is given in Table II.1. The scope of this feasibility study covers technical testing as well as sustainable operation and management, including the provision of training to local staff and improving the disaster management planning structure in local communities for increased disaster preparedness. + +**Table II.1 – Summary of project** + +| | | +|---------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Project scope |

Test the feasibility of the newly developed MDRU in disaster-affected areas, including a suitable location for installation.

Provide adequate training to local key personnel for sustainable operation and management of the MDRU network.

Improve disaster management planning structure in local communities for increased disaster preparedness.

Gain feedback from government organizations and local communities on the services powered by the MDRU.

Provide feedback on the project to government organizations through monitoring and evaluation of the installed MDRU.

| +| Project management |

The project is led by ITU. The ITU Project Manager provides the overall administration of the project in close collaboration with MIC and DOST.

A steering committee was established immediately after the signing of the co-operation agreement.

| +| Monitoring |

ITU will monitor and evaluate the project based on the expected results and key performance indicators.

| +| Term |

May 2014 – September 2015

| + +### II.3 Launching the feasibility study + +After agreement of the co-operation contract among relevant companies, preparation for the feasibility study was started in collaboration with local government staff members and residents. The installation of the MDRU, project administration and support were jointly carried out by Japanese and Filipino private companies. Japanese companies provided the MDRU server unit, the MDRU wireless system and heavy-duty smartphones. The MDRU server unit and the MDRU wireless system used in the project are shown in Figure II.2. They were installed in December 2014 in the San Remigio Municipal Hall and the wireless equipment was installed in a national high school (about 400 m away from the hall) where an evacuation centre had been set up. Point-to-point wireless equipment provided a communication link between the Municipal Hall and the high school. The MDRU team established a wide area WiFi network by employing an access point to access point (AP-AP) connection between the WiFi APs at the municipal hall and those at the high school, and a 24 GHz FWA connection between the two buildings [b-Shimizu, 2015]. We confirmed through the feasibility study that the MDRU operated effectively in the environment in the Philippines even though there were some differences between Japan and the Philippines. + +![Diagram of the MDRU and wireless equipment installation at the San Remigio Municipal Hall and a high school.](fa01531ea2c45beeb4036005da3037a4_img.jpg) + +The diagram illustrates the network architecture for the MDRU (Movable and Deployable Radio Unit) and wireless equipment. On the left, the 'Municipal hall' contains the 'MDRU' server unit and is connected to 'Health centre', 'Police', and 'National high school'. The 'National high school' contains 'Staff room', 'Computer room', and an 'Evacuation area'. The network is composed of several Access Points (APs): AP1, AP2, AP3, AP4, AP5, and AP6. AP1, AP2, and AP3 are located within the Municipal hall, while AP4, AP5, and AP6 are located within the National high school. The connections are as follows: AP5 (Health centre) connects to AP4 (National high school) via an 'AP relay (5 GHz)' link; AP4 connects to AP3 (Municipal hall) via another 'AP relay (5 GHz)' link; AP3 connects to the MDRU server unit; AP3 also connects to AP2 (Municipal hall) via an 'AP relay (5 GHz)' link; AP2 connects to AP1 (Municipal hall) via an 'AP relay (5 GHz)' link; AP1 connects to the 'Police' via an 'Access 2.4 G' link; AP2 connects to the 'National high school' via a '24-GHz FWA (400 m)' link; AP6 (National high school) connects to the 'Staff room' via an 'Access 2.4 G' link; AP6 also connects to the 'Evacuation area' via an 'AP relay (5 GHz)' link; and the 'Evacuation area' connects to the 'Computer room' via an 'Access 2.4 G' link. A photograph of the MDRU server unit is shown in the bottom right corner. + +Diagram of the MDRU and wireless equipment installation at the San Remigio Municipal Hall and a high school. + +L.392(16)\_FII.2 + +**Figure II.2 – Movable and deployable ICT resource unit and wireless equipment installed in the San Remigio Municipal Hall and in a high school** + +An example of use in the event of a disaster is shown in Figure II.3. In this case, the mayor first called municipal employees on the phone to get information about the disaster. Then, the municipal employees took pictures of the disaster-affected area with a smartphone and saved them on the server in the MDRU. This enabled the mayor to gain a visual understanding of the disaster-affected area by looking at the pictures stored on the server. The mayor then instructed Municipal Hall employees to provide relief goods to the affected area and then reported on the situation to the central government. + +![A photograph of a long hallway in a municipal hall, lined with stacks of relief supplies on the left and large white sacks on the right.](008b6e24fa6aef654a11223efed035dd_img.jpg) + +A photograph of a long hallway in a municipal hall, lined with stacks of relief supplies on the left and large white sacks on the right. + +Relief supplies stored at San Remigio Municipal Hall. + +![A photograph of a man in a yellow jacket talking on a smartphone while standing at a desk with papers.](045c7af3c493369642487e4d52e15065_img.jpg) + +A photograph of a man in a yellow jacket talking on a smartphone while standing at a desk with papers. + +(2) The mayor obtains information on the disaster affected area via smartphone; he gets updates from employees and looks at images of the area stored on a server. + +Smartphone + +![A photograph of a smartphone displaying a grid of images showing disaster-affected areas.](11728b408ca6402f502858c9bc161c4a_img.jpg) + +A photograph of a smartphone displaying a grid of images showing disaster-affected areas. + +![A photograph of a smartphone displaying a grid of images showing disaster-affected areas.](4a7229c854e8286e8d38fc192a3ba1d4_img.jpg) + +A photograph of a smartphone displaying a grid of images showing disaster-affected areas. + +(1) Pictures of disaster-affected area are taken with a smartphone and stored on MDRU server. + +**Figure II.3 – Use case of a movable and deployable ICT resource unit: Investigating the extent of damage from the typhoon** + +It is planned to continue working to improve some operation rules, the connectivity and the specifications of the MDRU by conducting a feasibility study of each use case in order to meet the needs of municipal employees and local residents. + +# Bibliography + +- [b-ITU-T E.108] Recommendation ITU-T E.108 (2016), *Requirements for a disaster relief mobile message service*. +- [b-FG-DR, 2014] ITU-T Focus Group on Disaster Relief Systems, Network Resilience and Recovery (2014), *Requirements for disaster relief system*. +- [b-FG-Frame, 2014] ITU-T Focus Group on Disaster Relief Systems, Network Resilience and Recovery (2014), *Disaster relief systems, network resilience and recovery (DR&NRR): Promising technologies and use cases*. +- [b-FG-Gap, 2014] ITU-T Focus Group on Disaster Relief Systems, Network Resilience and Recovery (2014), *Gap analysis of disaster relief systems, network resilience and recovery*. +- [b-FG-NRR, 2014] ITU-T Focus Group on Disaster Relief Systems, Network Resilience and Recovery (2014), *Requirements for network resilience and recovery*. +- [b-FG-Overview, 2014] ITU-T Focus Group on Disaster Relief Systems, Network Resilience and Recovery (2014), *Overview of disaster relief systems, network resilience and recovery*. +- [b-FG-Term, 2014] ITU-T Focus Group on Disaster Relief Systems, Network Resilience and Recovery (2014), *Terms and definitions for disaster relief systems, network resilience and recovery*. +- [b-ITU-TR, 2013] ITU-T Focus Group on Disaster Relief Systems, Network Resilience and Recovery, Technical report (2013), *Technical report on telecommunications and disaster mitigation*. +- [b-ICTCar, 2014] NTT press release (18 January 2014), "ICT Car" enables communication to promptly recover after large-scale disasters. (2014) +- [b-Kotabe, 2015] Kotabe, S., Sakano, T., Komukai, T. (2015) ICT service for MDRUs, *NTT Technical Review*, **13**(5). +- [b-NDRRMC, 2014] National Disaster Risk Reduction and Management Council, *Update on effects of typhoon Yolanda (Haiyan)*. (2014). [http://www.ndrrmc.gov.ph/attachments/article/1329/Update\\_on\\_Effects\\_Typhoon\\_YOLANDA\\_\(Haiyan\)\\_17APR2014.pdf](http://www.ndrrmc.gov.ph/attachments/article/1329/Update_on_Effects_Typhoon_YOLANDA_(Haiyan)_17APR2014.pdf) +- [b-Sakano, 2013a] Sakano, T., Fadlullah, Z.M., Thuan Ngo, Nishiyama, H., Nakazawa, M., Adachi, F., Kato, N., Takahara, A., Kumagai, T., Kasahara, H., Kurihara, S. (2013), Disaster resilient networking – A new vision based on movable and deployable resource units (MDRUs), *IEEE Network*, **27**(4), pp. 40-46. +- [b-Sakano, 2013b] Sakano, T., Kotabe, S., Sebayashi, K., Komukai, T., Kubota, H., Takahara, A. (2013), A rapidly restorable phone service to counter catastrophic loss of telecommunications facilities, *Humanitarian Technology Conference (R10-HTC)*, 2013 IEEE Region 10, pp. 200-205. + +- [b-Sakano, 2013c] Sakano, T., Kootabe, S., Sebayashi, K., Komukai, T., Takahara, A. (2013), Improvement of network/service resiliency with a movable and deployable ICT resource unit, *Signal-Image Technology & Internet-Based Systems (SITIS)*, pp. 883-888. +- [b-Sakano, 2015] Sakano, T., Kotabe, S. Komukai, T. (2015), Overview of movable and deployable ICT resource unit architecture. *NTT Technical Review*, **13**(5) + +- [b-Shimizu, 2015] Shimizu, Y., Suzuki, Y., Kumagai, T., Goto, K. (2015) Wireless access network system using M2M wireless access for MDRU, *NTT Technical Review*, **13**(5). + + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.4-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg b/marked/L/T-REC-L.4-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..64672153e39c851d9e16fdbc702e526c7ba7e8a7 --- /dev/null +++ b/marked/L/T-REC-L.4-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:454a9958ffe168868cb7d38a0eb24418dafe31a7a4245c992089b2316ac37d3e +size 7392 diff --git a/marked/L/T-REC-L.4-198811-I_PDF-E/raw.md b/marked/L/T-REC-L.4-198811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..3dd84bc5c0325ca5703e150e8c40114f9bc021c8 --- /dev/null +++ b/marked/L/T-REC-L.4-198811-I_PDF-E/raw.md @@ -0,0 +1,161 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features the letters 'ITU' in a bold, sans-serif font, superimposed on a stylized globe with intersecting lines. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**L.4** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**CONSTRUCTION, INSTALLATION AND +PROTECTION OF CABLES AND OTHER ELEMENTS +OF OUTSIDE PLANTS** + +--- + +**ALUMINIUM CABLE SHEATHS** + +**ITU-T Recommendation L.4** + +(Extract from the *Blue Book*) + +--- + +# NOTES + +1 ITU-T Recommendation L.4 was published in Volume IX of the *Blue Book*. This file is an extract from the *Blue Book*. While the presentation and layout of the text might be slightly different from the *Blue Book* version, the contents of the file are identical to the *Blue Book* version and copyright conditions remain unchanged (see below). + +2 In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +# **ALUMINIUM CABLE SHEATHS** + +*(Geneva, 1972; modified at Geneva, 1976, Malaga-Torremolinos, 1984 and Melbourne, 1988)* + +## **1 General** + +Because of the technological progress made in the use of aluminium, aluminium cable sheaths are being used on an increasing scale and their favourable characteristics can now be fully exploited. + +These characteristics include: + +- low density (almost a quarter that of lead); +- much higher mechanical strength than lead, so that the sheath is lighter not only because aluminium is lighter than lead, but because the thickness may be less than for lead; +- very high resistance to vibration; +- high conductivity, so that a better screening factor and more effective protection from overvoltages of atmospheric origin can be obtained. + +It is now found that the stiffness of an aluminium sheath does not give rise to any additional serious problems during laying. + +However, because aluminium is more vulnerable than lead to electrochemical and electrolytic corrosive action, aluminium cable sheaths and the joints between individual factory lengths (jointing sleeves and adjacent sections of cable) require a Class II (see [1]) outer protective covering of plastic material. + +As can be seen from the foregoing, an aluminium sheath has many advantages over a lead sheath. The generalized use of aluminium for sheathing cables is therefore desirable, at least whenever cable costs would not be increased compared with the use of lead, and also whenever aluminium sheaths satisfy the technical requirements to a greater extent. The use of cables with aluminium sheaths is particularly interesting in the case of trunk cables. + +## **2 Types of aluminium sheath** + +### **2.1 Extruded sheaths** + +This type of sheath is obtained by extruding the aluminium directly around the cable core. The press may be of the *continuous* type or not. If it is not continuous, care must be taken to ensure that no problems are caused in the zones affected by the intermittent nature of the process. + +### **2.2 Welded sheaths** + +This type of sheath is made by applying around the cable core an aluminium strip which is longitudinally welded. + +### **2.3 Quality of sheath material** + +In order to make the means of protection against corrosion effective, great care has to be taken concerning the quality of the sheath. In case pure aluminium is used, the purity of aluminium for the sheath should not be lower than 99.5% grade, for both the extruded sheath or the welded sheath. + +### **2.4 Choice of sheath shape and thickness** + +After the sheath has been extruded or welded it may either be shrunk on to the cable core (noncorrugated sheath) or corrugated by a variety of methods (corrugated sheath). + +The sheath may be corrugated or noncorrugated, depending on the diameter of the cable core, the minimum radius of curvature during laying and on the mechanical characteristics of the aluminium used (see [2]). As a rough guide it can be stated that the sheath should be corrugated in the case of cables of more than 40-mm core diameter. + +As stated in § 1 above the thickness of the metal used for aluminium sheaths is usually less than for lead sheaths. + +The thicknesses given in Table 1/L.4 are suggested although the values given in this table apply to both extruded and welded sheaths; however, extruded sheaths may not be less than 0.9 mm and welded sheaths may not be more than 1.4 mm, that being the maximum thickness which can be welded by existing methods. + +The use of lesser thicknesses than those indicated in Table 1/L.4 is not excluded and, conversely, in the case of coaxial cables without armouring, the thickness of metal for all sheaths may have to be increased to improve mechanical protection. The increase in the thickness may be as much as approximately 0.3 mm. + +Values different from those given in Table 1/L.4 may, of course, be adopted in certain cases (for example, if extremely favourable screening factors are required). + +## 3 Protective coverings + +As stated above, since aluminium used in an underground environment is more liable to corrosion than lead, an impermeable (Class II) covering should be provided in accordance with reference [1] to ensure the protection of the cable sheath and the jointing sections of individual factory lengths of cable (jointing sleeves and adjacent sections of cable). + +Two types of plastic material can be used at present for protective coverings: + +- a) polyvinylchloride (PVC); +- b) polyethylene. + +Polyethylene is preferable since its general characteristics and its low permeability for water vapour give better protection to the aluminium. + +To ensure that moisture which may have penetrated the protective covering (for example, because of a defect in the covering) does not spread along the surface of the sheath, extending the areas of corrosion, it is essential to apply a leakproof layer consisting of an adhesive tape or a suitable mixture. + +The leakproof layer must adhere well to the aluminium, especially when PVC is used for the covering, since this material, unlike polyethylene, does not cling tightly to the sheath after extrusion. + +The protective covering on the aluminium sheath should be sound. One form of test with the cable on the drum is to measure the insulation resistance of the covering. + +TABLE 1/L.4 + +### **Suggested thickness** + +| Core diameter (mm) | | Metal thickness (mm) | | +|--------------------|---------|-----------------------|----------------------------------| +| Minimum | Maximum | Noncorrugated sheaths | Corrugated sheaths a) | +| – | 10 | 0.7 to 1.0 | 0.5 to 0.9 | +| 10 | 15 | 0.7 to 1.0 | 0.6 to 0.9 | +| 15 | 20 | 0.9 to 1.0 | 0.7 to 0.9 | +| 20 | 25 | 1.1 | 0.8 to 0.9 | +| 25 | 30 | 1.1 to 1.2 | 0.9 | +| 30 | 35 | 1.1 to 1.3 | 0.9 to 1.0 | +| 35 | 40 | 1.1 to 1.4 | 1.1 | +| 40 | 45 | 1.5 | 1.1 to 1.2 | +| 45 | 50 | 1.6 | 1.1 to 1.2 | +| 50 | 60 | | 1.1 to 1.3 | +| 60 | 70 | | 1.1 to 1.4 | +| 70 | 80 | | 1.3 to 1.5 | + +- a) If it is intended to obtain approximately the same screening factor with a corrugated sheath as with a noncorrugated one, the thickness should be the same as with a noncorrugated sheath. + +In the case of corrugated sheaths, the bituminous mixture must fill the corrugations sufficiently to allow complete contact with the outer covering. + +Special tests should be made of the efficiency of the leakproof layer. A common test consists in removing a part of the protective covering from a sample of the aluminium sheath and submitting it to electrolytic attack using an outside source of e.m.f. After some time, a check must be made to see whether the corrosion is confined to the place from which the protective covering was removed. The effectiveness of the protective covering can be assessed by means of a test to check the adhesion of the bituminous compound to both the aluminium sheath and the plastic covering. + +To ensure the permanent effectiveness of the protective covering when cables are laid in areas exposed to lightning discharges (in particular as concerns avoiding perforations due to lightning discharges) the indications given in the manual cited in [3] should be taken into account. + +If a test of the protective covering is necessary in the manufacturing process, an electric spark detect method or a voltage resistance test method with the cable submerged in water is effective. In the process of installation and operation, if the factors that might cause damage to the protective covering or decrease the protective covering's insulation resistance are to be found, the test should be carried out and the faults should be eliminated. + +## 4 Jointing of aluminium sheaths + +Jointing is undoubtedly a more difficult operation for aluminium than for lead sheaths, although these difficulties have been minimized by improved techniques. + +There are several methods of jointing aluminium sheaths: + +- jointing by means of lead sleeves; +- jointing by means of lead rings or cones which are plumbed using a normal method or fixed with special glue to the aluminium sheath to permit subsequent soldering to lead sleeves; +- jointing by means of aluminium sleeves joined to the aluminium sheath by pressure welding (explosion, pressure or cold welding); +- other methods including the use of adhesive tapes and epoxy pastes. + +The methods used for the jointing of aluminium sheaths must meet the conditions recommended in the booklet cited in [4]. + +For an aluminium-sheathed cable subjected to significant temperature variations, tensions due to cable contraction should not be borne by the joints as this can lead to joint failure, particularly with noncorrugated sheaths. + +## 5 Cathodic protection + +The corrosion protection of aluminium sheaths depends mainly on a high quality anti-corrosion protective cover. However, if there is serious risk of damage to the protective cover, and particularly if it is not possible to re-establish the protective cover to its original specifications after repair, the cover should be protected with special measures such as sacrifice anode electrical chemical protection. Aluminium alloy sacrifice anode, which has the advantage of a higher current capacity per unit weight, an appropriate protective potential, an abundant raw material resource base, and ease of manufacture, is an effective measure to protect aluminium sheathed cables. Tests show that good results can be obtained if the protected aluminium sheath potential value with respect to ground is limited within the range of $-0.85$ to $1.20$ V (relative to a $\text{Cu/CuSO}_4$ electrode). + +6 If there are no special requirements in using aluminium sheaths for optical fibre cables, the same sheath material and manufacturing process may be used as for metallic conductor cables. + +## References + +- [1] CCITT manual *Outside plant technologies for public networks*, Part IV-A, Chapter III, § 1.2.2, ITU, Geneva 1988. +- [2] *Ibid.*, Part I, Chapter III, § 6.2.2. +- [3] CCITT manual *The protection of telecommunication lines and equipment against lightning discharges*, ITU, Geneva, 1974, 1978. +- [4] CCITT manual *Jointing of plastic-sheathed cables*, ITU, Geneva, 1978. \ No newline at end of file diff --git a/marked/L/T-REC-L.400-202202-I_PDF-E/05c9994c1f5daf53d0d9b107657d7a17_img.jpg b/marked/L/T-REC-L.400-202202-I_PDF-E/05c9994c1f5daf53d0d9b107657d7a17_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..d0834857f154fe8984e9243c02b17ab217a5df14 --- /dev/null +++ b/marked/L/T-REC-L.400-202202-I_PDF-E/05c9994c1f5daf53d0d9b107657d7a17_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:acbdee22ad4959f32c10f20a3c9731863b410e62497e1be26cbfc3918c1bfca9 +size 106492 diff --git a/marked/L/T-REC-L.400-202202-I_PDF-E/4801720824e4b5e2361a5564f91cfb70_img.jpg b/marked/L/T-REC-L.400-202202-I_PDF-E/4801720824e4b5e2361a5564f91cfb70_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..e95898ee8ca6a959ec522829512fab55dab5f42c --- /dev/null +++ b/marked/L/T-REC-L.400-202202-I_PDF-E/4801720824e4b5e2361a5564f91cfb70_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:47fb5e08b9c0a76c429df237fbfa06d0280a641ed95062ed5ca356bdcab8e860 +size 68538 diff --git a/marked/L/T-REC-L.400-202202-I_PDF-E/56a7fc5964ed9463fa47ca8a60568dec_img.jpg b/marked/L/T-REC-L.400-202202-I_PDF-E/56a7fc5964ed9463fa47ca8a60568dec_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..5d061f9e01dbc2e0f5828fe1b394fadee8dd1cde --- /dev/null +++ b/marked/L/T-REC-L.400-202202-I_PDF-E/56a7fc5964ed9463fa47ca8a60568dec_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:5dfa46abf82696e7803a1fc216ee4696f2ed1bd1e993bed80cd12e1ddae6ace5 +size 15058 diff --git a/marked/L/T-REC-L.400-202202-I_PDF-E/9b6b5924b48bf2fd5f347f88f06f45b3_img.jpg b/marked/L/T-REC-L.400-202202-I_PDF-E/9b6b5924b48bf2fd5f347f88f06f45b3_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..a37604678bceb30e6cfb8f128a2b2d40b24d968a --- /dev/null +++ b/marked/L/T-REC-L.400-202202-I_PDF-E/9b6b5924b48bf2fd5f347f88f06f45b3_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:c08e5b104262a5dbbff924431fc74c1020e9c83ef6a05bd927981362b1943885 +size 32533 diff --git a/marked/L/T-REC-L.400-202202-I_PDF-E/ae02603e9e4b46477222bf72c1c7c7f6_img.jpg b/marked/L/T-REC-L.400-202202-I_PDF-E/ae02603e9e4b46477222bf72c1c7c7f6_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..a334bd2289af5ae1c24a47535104753ed14e2bd1 --- /dev/null +++ b/marked/L/T-REC-L.400-202202-I_PDF-E/ae02603e9e4b46477222bf72c1c7c7f6_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:59e6f92bc34a677e96401239c8dc9627a3a4da34c2024193902d554a2799b6df +size 14534 diff --git a/marked/L/T-REC-L.400-202202-I_PDF-E/d3294dc879b451b369c0b06f42e9b39f_img.jpg b/marked/L/T-REC-L.400-202202-I_PDF-E/d3294dc879b451b369c0b06f42e9b39f_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..2223a66fbbfbdb1685507fbb9583e1c4f95f5683 --- /dev/null +++ b/marked/L/T-REC-L.400-202202-I_PDF-E/d3294dc879b451b369c0b06f42e9b39f_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:2186dd565429c9bc3911c13c0d9496fe83da7e4a10409328b4dfe683b4eb9fc3 +size 6132 diff --git a/marked/L/T-REC-L.400-202202-I_PDF-E/d9c0a780cd22626253dab4aa41699e2f_img.jpg b/marked/L/T-REC-L.400-202202-I_PDF-E/d9c0a780cd22626253dab4aa41699e2f_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..829a4c1206a1171c1fd526176182dd19b44df5d8 --- /dev/null +++ b/marked/L/T-REC-L.400-202202-I_PDF-E/d9c0a780cd22626253dab4aa41699e2f_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:04580c59556cb127f904a8c1df8bf3d02b9b1f17ffc7338998c129b218343ee0 +size 42505 diff --git a/marked/L/T-REC-L.400-202202-I_PDF-E/raw.md b/marked/L/T-REC-L.400-202202-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..2cab90892b4a8c17e83b879ceb4832d8fc285d8b --- /dev/null +++ b/marked/L/T-REC-L.400-202202-I_PDF-E/raw.md @@ -0,0 +1,741 @@ + + +**ITU-T** + +**L.400/L.12** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +(02/2022) + +SERIES L: ENVIRONMENT AND ICTS, CLIMATE +CHANGE, E-WASTE, ENERGY EFFICIENCY; +CONSTRUCTION, INSTALLATION AND PROTECTION +OF CABLES AND OTHER ELEMENTS OF OUTSIDE +PLANT + +Passive optical devices + +SERIES L: ENVIRONMENT AND ICTS, CLIMATE +CHANGE, E-WASTE, ENERGY EFFICIENCY; +CONSTRUCTION, INSTALLATION AND PROTECTION +OF CABLES AND OTHER ELEMENTS OF OUTSIDE +PLANT + +Passive optical devices + +# --- **Optical fibre splices** + +Recommendation ITU-T L.400/L.12 + +![ITU logo](d3294dc879b451b369c0b06f42e9b39f_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with white lines representing latitude and longitude, and the letters 'ITU' in a bold, blue, sans-serif font superimposed on the globe. + +ITU logo + +## ITU-T L-SERIES RECOMMENDATIONS + +## ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT + +| | | +|--------------------------------------------------------|--------------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node elements (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000–L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200–L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300–L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400–L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500–L.1599 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700–L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +## Recommendation ITU-T L.400/L.12 + +# Optical fibre splices + +## Summary + +Recommendation ITU-T L.400/L.12 specifies splices of single-mode and multimode optical fibres. It describes suitable procedures for splicing that should be carefully followed in order to obtain reliable splices between single optical fibres or ribbons. The procedures apply to both single optical fibres and ribbons (mass splicing). + +Splices are critical points in the optical fibre network, because they strongly affect the quality and lifetime of links. In fact, the splice should ensure high quality and stability of performance with time. High quality in splicing is usually characterized by low splice loss and tensile strength near that of the fibre proof test level. Splices should be stable over the design life of the optical fibre link under its expected environmental conditions. + +At present two technologies, fusion and mechanical, can be used for splicing glass optical fibres and the choice between them depends upon the expected functional performance and considerations of installation and maintenance. These splices are designed to provide permanent connections. + +The following elements have been modified in this edition of Recommendation ITU-T L.400/L.12: + +- maximum attenuation of fibre splices depending on the alignment method (active core, active cladding and passive V-groove alignment); +- maximum attenuation for mechanical splices; +- validation of splicing procedure is added with average and maximum attenuation (97% of the splices) of fibre splices; +- the appendix with Japanese experience is removed; +- inclusion of Appendix II, which shows the increase in attenuation when splicing different types of optical fibres by taking into account the mode field diameter mismatch, the core-cladding concentricity and the cladding diameter; +- inclusion of Appendix III, which explains the fibre imaging process in fusion splicing machines. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|------------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.12 | 1992-07-31 | | 11.1002/1000/1416 | +| 2.0 | ITU-T L.12 | 2000-05-12 | 6 | 11.1002/1000/5062 | +| 3.0 | ITU-T L.400/L.12 | 2008-03-08 | 6 | 11.1002/1000/9323 | +| 4.0 | ITU-T L.400/L.12 | 2022-02-13 | 15 | 11.1002/1000/14939 | + +## Keywords + +Fusion splice, mechanical splice, optical fibre splice. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2022 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-----------------------------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 3 | +| 3.1 Terms defined elsewhere ..... | 3 | +| 3.2 Terms defined in this Recommendation..... | 3 | +| 4 Abbreviations and acronyms ..... | 3 | +| 5 Conventions ..... | 3 | +| 6 Types of splices – general description..... | 3 | +| 6.1 Fusion splices ..... | 3 | +| 6.2 Mechanical splices..... | 4 | +| 7 Splicing procedure steps ..... | 4 | +| 7.1 Fibre cleaning and end preparation ..... | 4 | +| 7.2 Coating stripping ..... | 4 | +| 7.3 Cleaning of the stripped fibre section..... | 5 | +| 7.4 Fibre cleaving ..... | 5 | +| 7.5 Splicing..... | 5 | +| 7.6 Field splice loss measurements ..... | 9 | +| 8 Requirements of the fibre splices and recommended performance tests..... | 10 | +| 8.1 General..... | 10 | +| 8.2 Performance requirements for single-mode fibre splices..... | 10 | +| 8.3 Validation of the splicing procedure ..... | 12 | +| 8.4 Performance characteristics for multimode fibre splices ..... | 13 | +| Appendix I – Index of refraction matching materials for mechanical optical fibre splices..... | 14 | +| Appendix II – Optical fibre splice attenuation with different types of fibres ..... | 15 | +| Appendix III – Fibre imaging in fusion splicing machines ..... | 18 | +| Bibliography..... | 21 | + + + +# Optical fibre splices + +## 1 Scope + +This Recommendation specifies splices of single-mode and multimode optical fibres. It describes suitable procedures for splicing that should be carefully followed in order to obtain reliable splices between single optical fibres or ribbons. The procedures apply to both single optical fibres and ribbons (mass splicing). + +In addition, this Recommendation describes the optical, mechanical and environmental properties, recommended test methods and recommended test severities that should be considered for an optical fibre splice. Moreover, validation tests of the splice procedure are given to obtain the expected optical splice properties. + +Further information is provided in chapter 6 of [b-ITU-T TR-OFCS]. The fibres should be in accordance with [ITU-T G.651.1], [ITU-T G.652], [ITU-T G.653], [ITU-T G.654], [ITU-T G.655], [ITU-T G.656] and [ITU-T G.657]. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T G.651.1] Recommendation ITU-T G.651.1 (2018), *Characteristics of a 50/125 µm multimode graded index optical fibre cable for the optical access network.* +- [ITU-T G.652] Recommendation ITU-T G.652 (2016), *Characteristics of a single-mode optical fibre and cable.* +- [ITU-T G.653] Recommendation ITU-T G.653 (2010), *Characteristics of a dispersion-shifted, single-mode optical fibre and cable.* +- [ITU-T G.654] Recommendation ITU-T G.654 (2020), *Characteristics of a cut-off shifted single-mode optical fibre and cable.* +- [ITU-T G.655] Recommendation ITU-T G.655 (2009), *Characteristics of a non-zero dispersion-shifted single-mode optical fibre and cable.* +- [ITU-T G.656] Recommendation ITU-T G.656 (2010), *Characteristics of a fibre and cable with non-zero dispersion for wideband optical transport.* +- [ITU-T G.657] Recommendation ITU-T G.657 (2016), *Characteristics of a bending loss insensitive single-mode optical fibre and cable.* +- [IEC 61300-1] IEC 61300-1:2016, 1 *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 1: General and guidance.* + +--- + +1 Withdrawn. + +- [IEC 61300-2-1] IEC 61300-2-1:2009, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-1: Tests – Vibration (sinusoidal).* +- [IEC 61300-2-4] IEC 61300-2-4:2019 + AMD1:2020, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-4: Tests – Fibre or cable retention.* +- [IEC 61300-2-5] IEC 61300-2-5:2009, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-5: Tests – Torsion.* +- [IEC 61300-2-7] IEC 61300-2-7:2013, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-7: Tests – Bending moment.* +- [IEC 61300-2-9] IEC 61300-2-9:2017, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-9: Tests – Shock.* +- [IEC 61300-2-17] IEC 61300-2-17:2010, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-17: Tests – Cold.* +- [IEC 61300-2-18] IEC 61300-2-18:2005, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-18: Tests – Dry heat – High temperature endurance.* +- [IEC 61300-2-21] IEC 61300-2-21:2009, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-21: Tests – Composite temperature/humidity cyclic test.* +- [IEC 61300-2-22] IEC 61300-2-22:2007, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-22: Tests – Change of temperature.* +- [IEC 61300-2-26] IEC 61300-2-26:2006, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-26: Tests – Salt mist.* +- [IEC 61300-2-27] IEC 61300-2-27:1995, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-27: Tests – Dust – Laminar flow.* +- [IEC 61300-2-45] IEC 61300-2-45:1999, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-45: Tests – Durability test by water immersion.* +- [IEC 61300-3-3] IEC 61300-3-3:2009, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 3-3: Examinations and measurements – Active monitoring of changes in attenuation and return loss.* +- [IEC 61300-3-4] IEC 61300-3-4:2012, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 3-4: Examinations and measurements – Attenuation.* +- [IEC 61300-3-6] IEC 61300-3-6:2008, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 3-6: Examinations and measurements – Return loss.* + +## 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +None + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following term: + +**3.2.1 optical fibre splice:** Permanent or separable joint whose purpose is to couple optical power between two optical fibres, achieved by either a fusion or a mechanical technique. + +## 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|-----------------------------------| +| IL | Insertion Loss | +| MFD | Mode Field Diameter | +| OTDR | Optical Time Domain Reflectometer | +| RH | Relative Humidity | +| RL | Return Loss | +| UV | Ultraviolet | + +## 5 Conventions + +None. + +## 6 Types of splices – general description + +All optical fibre splices mentioned in this Recommendation should be suitable for indoor applications as well as for outdoor environments when stored in an appropriate enclosure. + +### 6.1 Fusion splices + +Different methods exist to obtain a fusion splice of single fibres or ribbons. Electric arc-fusion is the most widely used method to make reliable single or mass optical splices in the field. The fusion process is realized by using specially developed splicing machines. + +To make a fusion splice, all protective coatings are removed from the fibres, and the fibres are cleaved and then positioned and aligned between two electrodes in the splicing machine. An electric arc heats the glass until the melting or softening point is reached and at the same time the fibres are brought together longitudinally in such a way that a geometrically continuous glass filament is obtained. The fibre alignment in these machines can be passive (V-groove alignment) or active (light injection and detection system or core and cladding profile monitoring and alignment system). A suitable protection device is then applied to the splice area to protect the bare fibre and to allow handling and storage without adversely affecting the physical integrity of the splice. The cleave quality and the intensity and the duration of the arc, as well as the differences between the fibres (refractive index profile, mode field diameter (MFD), core-cladding concentricity, cladding diameter) to be spliced determine the splice loss. In addition, the quality of coating removal, fibre cleaving, and splice protection contribute to long-term mechanical reliability in the field. + +### 6.2 Mechanical splices + +Mechanical splices have different structures and physical designs, and usually include the following basic components: + +- a surface for aligning mating fibre ends; +- a retainer to keep the fibres in alignment; +- an index-matching material (gel, grease, adhesive, etc.) placed between the fibre ends. + +Mechanical splices can be used for single fibres or ribbons. Some designs allow installation on the fibres at the end of a cable in the factory for faster jointing in the field. + +An optical matching material between the ends of the fibres can be used to reduce Fresnel reflections. This material should be chosen to match the optical properties of the fibre. Common index-matching materials include silicon gels, ultraviolet-curable (UV-curable) adhesive, epoxy resins and optical greases. The refractive index of the index-matching material is temperature dependent, which could result in a change in return loss (RL) when the ambient temperature changes. More detailed information on index-matching materials can be found in Appendix I. + +As for fusion splices, the cleave quality as well as the differences between the fibres (refractive index profile, MFD, core-cladding concentricity, etc.) to be spliced determine the splice loss. + +## 7 Splicing procedure steps + +### 7.1 Fibre cleaning and end preparation + +For gel-filled cables, the fibres should be mechanically cleaned of the water-blocking compound of the cable using lint-free paper tissue or cotton cloth. Commercial solvents are available to assist in this cleaning. Care should be taken that the ribbon matrix material and the fibre coatings are not damaged either mechanically or chemically. Long-term soaking in solvents should not be allowed, as the fibre coating can be damaged. In addition, the solvent supplier should disclose all safety-related information about these products. + +The fusion splicing machine or mechanical splice assembly tool should be close to the joint enclosure, so that the fibres are not subjected to excessive bending, tensile or pressure stresses. + +The ends of the fibres to be spliced should be identified on the basis of the cable identification system that denotes the fibres in the cable. + +If protection tube sleeves are used, they should be placed over one end of the fibres or ribbons to be spliced before splicing. Clamshell-type protectors can be fitted after splicing is complete. + +### 7.2 Coating stripping + +Where applicable, secondary coatings (tight buffer or loose tube constructions) should be removed to the distance recommended by the splice protector manufacturer using an appropriate tool in order to expose the primary coating. + +Enough coating should be removed from the ends so that all bare fibre is covered by the protection device after cleaving and fusion splicing or by the mechanical splice. Coating removal could be the most critical operation in the splicing procedure, especially if it has to be performed on fibres that have been in the field for many years, because stripability may decline due to ageing. Therefore, this step must be performed carefully because the final strength of the completed splice depends on minimizing the exposure that can cause flaws in the bare fibre. + +The stripping method could be chemical, thermal or mechanical, depending on the application and desired performance. In the case of a chemical method, the manufacturer should supply all safety-related information about the stripping product. Typically, for underground, directly buried or aerial applications, mechanical stripping is used. The blade separation and alignment of the semi-circular + +or V-groove openings should be controlled to penetrate into the soft inner coating layer without scratching the fibre surface. The blades should be examined carefully and frequently. The blades should be well aligned, clean at all times and replaced if damaged or worn. Where the blades are an integral part of the stripper, the tool should be replaced. When thermal stripping methods are used, especially for ribbons, the coating should be heated to the temperature recommended by the ribbon manufacturer, and then removed by a blade. For submarine applications, the chemical method is more suitable for the higher proof test levels required. + +Holders are always used for stripping, cleaving and splicing fibre ribbons and are sometimes used for single fibre splicing systems. The ribbons are held in a holder prior to stripping and cleaving, as well as during the fusion process. The holder should ensure a good alignment of the fibres without damaging them. Only the coated part of the fibre or ribbon should be put into the holder, so that clamping does not cause any damage. The holders should be kept clean and free of debris. + +### **7.3 Cleaning of the stripped fibre section** + +When fibre end cleaning is needed, the stripped fibre sections should be cleaned with paper tissue soaked with reagent grade alcohol to eliminate residual coating, paying attention not to break them. Avoid wiping the fibre more than necessary to clean off debris. + +### **7.4 Fibre cleaving** + +The bare fibre ends should be cleaved perpendicular or angled to the longitudinal axis; and the cut surface should be mirror-like without chips or hackle. + +For fusion splices, end angles should be typically less than $1^{\circ}$ from perpendicular for single fibres and less than $3^{\circ}$ to $4^{\circ}$ for ribbons (depending on the fibre type) to achieve a satisfactory splice. The cleaving tool should be capable of achieving these values with a controlled length of bare fibre, compatible with the splicing system and protection device. + +For mechanical splices, two types can be identified. + +- Perpendicular cleave, with typically the same cleave angle as fusion splices. +- Angled cleave, with a cleave angle of at least $4^{\circ}$ . This is done to eliminate reflected light due to the mismatch between fibre glass and index-matching material at extreme temperature. When splices are assembled with angled cleaves instead of perpendicular cleaves, the reflected light is no longer completely captured and guided by the fibre core, but is directed to the fibre cladding where it is attenuated. + +The cleaving tool should be clean and properly adjusted to produce consistent fibre ends with the appropriate cleaving angle. Dirty cleaving tool clamping pads can cause flaws that make the fibre break at the wrong location or reduce the strength of the completed splice. The blade should score the fibre sufficiently to produce a clean break, but should not impact so hard on the fibre that it shatters. Cleaving tools that use bending to stress the fibres should be limited in their travel to avoid over-bending the fibres. For mass fusion, the cleaved bare fibre lengths should be approximately equal across the ribbon to provide uniform overlap on all of the fibres during fusion. The offcuts cleaved from the fibre should be collected and disposed of carefully to prevent injury. + +### **7.5 Splicing** + +#### **7.5.1 Electric arc-fusion splicing** + +##### **7.5.1.1 Control of the splicing parameters and conditions** + +Before using the splicing machine, it is fundamental to check its performance. The condition of the electrodes is a critical factor determining whether fusion splicing will proceed normally, especially when working at environmental extremes. + +A good indicator of the electrode condition and whether the machine parameters are set correctly for the type of fibre and environmental conditions is the degree to which fibres are "melt back" when subjected to the electric arc with the fibre feed turned off. Alternatively, some other substitute tests can be used to check the equipment. Some machines can automatically optimize the arc parameters; otherwise, manual adjustments are needed. + +Machine performance is sensitive to atmospheric variations. Either automatic or manual adjustment of arc parameters should be made to optimize for the existing conditions. + +The splicing machine should have the facility to count and indicate the arc number and the manufacturer should provide the number after which the electrodes should be replaced. The replacement should be in accordance with the instructions of the manufacturer. + +Since the optimal electric arc conditions (arc current, arc time, etc.) may depend on both the characteristics of the type of fibre as well as the characteristics of the splicing machine, it is recommended to use an arc test procedure, available in many splicing machines. + +NOTE 1 – Some splicing machines can optimize the arc position asymmetrically between the fibre ends of dissimilar fibres. When working under these settings, attention should always be paid to placing the appropriate fibre on the appropriate side of the fibre holder. + +NOTE 2 – Some splicing machines offer fibre type recognition algorithms, based on a particular interpretation of the fibre index profile. Care should be taken with these algorithms since index profiles have not been standardized. At least one check per commercial fibre type is recommended. + +##### 7.5.1.2 Fusion splicing + +When testing of the arc condition is completed, splicing can be commenced. The fibres should be positioned in the V-grooves or fibre clamps of the splicing machine. + +Fusion splicing machines, in general, are divided into two types according to alignment: active or passive. The use of either depends on how the fibres are aligned. Active alignment machines use either a vision system or local injection or local detection system and three-dimensional movement of the fibres to actively align the cores or cladding of the two fibres being spliced. The splicing machine minimizes the splice attenuation by either focusing on the core or cladding of the fibres with its vision system to directly align them or optimizing the transmitted light through the fibres and providing an estimate of the splice attenuation after the splice is complete. + +Those systems that compensate for core-cladding concentricity errors provide better results in terms of splice attenuation. Splicing machines that use active alignment systems are only suitable for single fibre splicing at this time. + +Passive alignment machines use only fibre longitudinal movement, so accurate core alignment mostly depends on good fibre or ribbon geometry. The passive alignment system can be used to splice ribbons or single fibres, and an estimate of splice attenuation may also be provided. For ribbon splicing, however, all current mass fusion machines estimate splice attenuation by observing fibre alignment before or after splicing. + +##### 7.5.1.3 Proof test + +After the splice is completed, it is recommended to check its minimum strength. It is very important to specify a level of mechanical strength for the splice that is related to its expected lifetime. As performed for optical fibres just after manufacturing, the splice is subjected to a tensile proof test for a short period of time. Some splicing machines perform this test with the spliced fibres in the splicing chucks and some perform it after placing the spliced fibres in the holders for heat-shrink protector application. Splices that have strength below the proof test level will be re-done. + +The splicing machine should be able to perform the proof test automatically or manually. The unloading time should be short in order to minimize the strength reduction during the unloading. + +Typical values for proof testing range from 2 N to 8 N, depending on the type of equipment and desired strength. + +##### **7.5.1.4 Splice protection** + +After the proof test, the protector should be positioned over the spliced point. The "protector" is a mechanical device or restored coating that provides both mechanical and environmental protection to single or multiple splices. In all cases, the protection device should affect neither the attenuation of the splice nor its functional properties. + +The characteristics of the completed fusion splice can be verified using the test methods and recommended acceptance criteria reported in clause 8. + +Protector designs may include heat-shrink sleeve, so called clam-shell, fibre re-coating and encapsulating protectors. The protectors for single fibre fusion splices should be capable of accepting coated fibres of (nominal) diameter 200 µm or 250 µm; 900 µm; or 200 µm, 250 µm and 900 µm combinations. Typically, these splice protectors require tools or equipment to install or make. + +The protector designs should be suitable for either aerial, underground or buried applications while stored inside an appropriate enclosure. The manufacturer should provide information on the compatibility with the splice trays and on the tools or equipment for its application. In particular, the manufacturer should provide information on the minimum and maximum fibre strip lengths that the protector will accommodate and on the storage dimensions for the completed protector (length, width and height) and on the application details. + +For heat-shrink sleeve protectors, the manufacturer should specify the time and the temperature required to complete the shrinkage, which should be taken into account by the oven settings. The function of the strength member, if present, is to improve the mechanical strength of the splice without affecting it, both from an optical and mechanical point of view. It should be straight and free from burrs and sharp edges. During cool-down, care should be taken to prevent deformations that cause bending attenuation. + +For UV-curable resin-filled protectors, the manufacturer should specify the total energy (exposure time and the power) applied by the UV lamp. + +Complete documentation containing all details, such as the manufacturer's references, the product code and the order mode, the use and application, as well as the repair and maintenance procedures, should be available with the product. The constituent materials should be compatible with the gel inside the cables and the protectors should be supplied with safety and operational instructions. + +Figure 1 shows a schematic representation of the fusion splicing procedure. + +![Flowchart of the fusion splicing procedure. The process starts with 'START', followed by 'Fibre identification', and 'Fibre ends preparation' (Coating removal, Cleaning, Cleaving). A callout 'Before the 1st splice' points to 'Arc condition testing', which leads to 'Control and optimization of the splicing parameters'. The main flow then goes to 'Fusion splicing', 'Proof-test', and a decision 'PASS'. If 'NO', it loops back to 'Fibre ends preparation'. If 'YES', it goes to 'Splice protection', 'END', and 'Field measurements'. An optional step 'Optional: Attenuation estimation or measurement' is shown between 'Proof-test' and 'PASS'.](4801720824e4b5e2361a5564f91cfb70_img.jpg) + +``` + +graph TD + START[START] --> FI[Fibre identification] + FI --> FEP[Fibre ends preparation +Coating removal +Cleaning +Cleaving] + FEP --> ACT[Arc condition testing] + ACT --> COP[Control and optimization +of the splicing parameters] + COP --> FS[Fusion splicing] + FS --> PT[Proof-test] + PT --> PASS((PASS)) + PASS -- NO --> FEP + PASS -- YES --> SP[Splice protection] + SP --> END[END] + END --> FM[Field measurements] + PT -.-> OPT[Optional: +Attenuation estimation +or measurement] + OPT -.-> PASS + B1S[Before the 1st splice] -.-> ACT + +``` + +L.400-L.12(22)\_F01 + +Flowchart of the fusion splicing procedure. The process starts with 'START', followed by 'Fibre identification', and 'Fibre ends preparation' (Coating removal, Cleaning, Cleaving). A callout 'Before the 1st splice' points to 'Arc condition testing', which leads to 'Control and optimization of the splicing parameters'. The main flow then goes to 'Fusion splicing', 'Proof-test', and a decision 'PASS'. If 'NO', it loops back to 'Fibre ends preparation'. If 'YES', it goes to 'Splice protection', 'END', and 'Field measurements'. An optional step 'Optional: Attenuation estimation or measurement' is shown between 'Proof-test' and 'PASS'. + +**Figure 1 – Schematic representation of the fusion splicing procedure** + +#### 7.5.2 Mechanical splicing + +The mechanical method allows fixing the fibres in a splice-protective housing, generally without the need for electrical power. Some mechanical splices can be tuned by hand for minimum splice loss. + +After stripping and cleaving operations, described in clauses 7.1 to 7.4, the bare fibre ends are inserted into the mechanical housing (in a guiding structure, for instance a V-groove) and checked for their physical contact. For angle-cleaved splices, it is recommended to maintain the relative orientation of the angled end faces of the fibres during installation in order to obtain optimal optical performance. + +For mechanical splices, proof test is generally not a part of the installation sequence as it is for fusion splices. + +Sometimes, the fibre ends are prepared for splicing by grinding and polishing procedures, especially in factory pre-terminated mass splices. + +The mechanical splices should be versatile, allowing the splicing of different types of fibres, e.g., coated fibres of (nominal) diameter 250 µm with buffered fibres of 900 µm. + +A protective housing provides mechanical and environmental protection of the splices (different for single and multiple splices). They should be suitable for aerial, underground or buried applications. The manufacturer should provide information on the compatibility with the splice organizer trays and on the tools or equipment for their application. + +The index-matching material used between the ends of the mating fibres should be chosen to match the optical properties of the glass. The supplier of the index-matching material should provide complete information about its behaviour at different temperatures (especially the extremes) and its estimated lifetime in terms of maintaining initial optical performance. + +The characteristics of the completed mechanical splice can be verified using the test methods and recommended acceptance criteria reported in clause 8. + +In mechanical splicing, the splice protection is built into the splice design and separate protectors are not required. + +A schematic representation of the mechanical splicing procedure is shown in Figure 2. + +![Flowchart of the mechanical splicing procedure](9b6b5924b48bf2fd5f347f88f06f45b3_img.jpg) + +``` +graph TD; START[START] --> FI[Fibre identification]; FI --> FEP["Fibre ends preparation
coating removal
cleaning
cleaving
or
grinding and polishing"]; FEP --> SA[Splice assembly]; SA --> END[END]; END --> FM[Field measurements]; +``` + +The flowchart illustrates the mechanical splicing procedure. It begins with 'START', followed by 'Fibre identification'. The next step is 'Fibre ends preparation', which includes 'coating removal', 'cleaning', 'cleaving', or 'grinding and polishing'. This is followed by 'Splice assembly', 'END', and finally 'Field measurements'. + +L.400-L.12(22)\_F02 + +Flowchart of the mechanical splicing procedure + +**Figure 2 – Schematic representation of the mechanical splicing procedure** + +### 7.6 Field splice loss measurements + +One critical requirement for an optical fibre communication system is the total end-to-end loss of each link. Considering the number of splices in a link, a realistic maximum splice loss should be set. + +In practice, the in-field measurement of each splice loss during the construction of a fibre link is usually estimated by the fusion splicing machine (when loss estimation is a facility) or by a one-way optical time domain reflectometer (OTDR) measurement. Either of these techniques can be used to + +evaluate gross high splice losses so that the splice may be remade if necessary. After construction is complete, the actual splice loss in the field can be determined by bidirectional OTDR measurement if necessary. + +For single-mode fibre the true splice loss is determined by the bidirectional average of the OTDR readings at a splice. A one-way OTDR measurement should not be used as actual splice loss because MFD tolerances and other intrinsic parameter differences in fibres can cause errors. In the case of single-mode fibres, OTDR single-direction readings can be high, being either positive or negative. In addition, any measurable spike from a fusion splice requires that the splice be remade. Acceptance levels for splice loss before remake depend on the loss budget of the link. + +More guidance on the interpretation of OTDR backscattering traces of splices can be found in [b-IEC TR 62316]. + +## 8 Requirements of the fibre splices and recommended performance tests + +### 8.1 General + +This clause validates the splice procedure described in clause 7 and qualifies the properties that should be considered for the optical fibre splice. The specimen is prepared on the same single-mode fibre (by cutting one fibre) that satisfies the specifications of [ITU-T G.651.1], [ITU-T G.652], [ITU-T G.653], [ITU-T G.654], [ITU-T G.655], [ITU-T G.656] and [ITU-T G.657] in order to avoid excessive splice properties that are independent of the splice procedure and caused by mode-field diameter mismatch, cladding diameter tolerance etc. + +In reality, spliced fibres have differences in MFD, cladding diameter, core-cladding eccentricity and even glass composition. The increased splice loss caused by the difference in fibre characteristics is given in Appendix II and can be added to the attenuation values in test 8.2.1 of Table 1 as an estimation of the true loss in case of splicing different fibre types. The maximum allowed attenuation value in the field should be decided by the network operator, as a function of the various kinds of installation (long distance, access, distribution or submarine network). Further information can be found in [b-IEC TR 62000] and in [b-ITU-T G.671]. + +Recommended test methods are described by referring the corresponding documents of the IEC 61300 series. These tests are to be executed at standard atmospheric conditions according to [IEC 61300-1]: + +| | | +|------------------------------------------|----------| +| Temperature (in degrees Celsius) | 18-28 | +| Relative humidity (RH) (as a percentage) | 25-75 | +| Air pressure (in hectopascals): | 860-1060 | + +### 8.2 Performance requirements for single-mode fibre splices + +Table 1 gives the recommended performance requirements for single-mode fibre splices made on the same optical fibre or ribbon. For each test, five test samples should be prepared that meet the maximum attenuation and RL requirements for the grade used of mechanical splice or fibre alignment method for the fusion splice. + +NOTE – The tests and test severities correspond with [b-IEC 61753-131-03], [b-EN 50411-3-2] and [b-EN 50411-3-3]. + +**Table 1 – Performance requirements for single-mode fibre splices** + +| No | Test | Method | Test severities | Mechanical splice | Fusion splice with protector | +|-------|----------------------------------------|-----------------------------------|----------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 8.2.1 | Attenuation/
Insertion loss
(IL) | IEC 61300-3-4 | Wavelengths:
1 310 nm, 1 550 nm
and 1 625 nm | Single fibre and ribbon
fibre splices:
Grade B
$\leq 0.25$ dB max
Grade C
$\leq 0.5$ dB max | Single fibre splices made
by:
– Active core alignment:
$\leq 0.1$ dB max
– Active cladding
alignment:
$\leq 0.2$ dB max
Ribbon fibre splices made
by:
– Passive alignment by
V-groove:
$\leq 0.2$ dB max | +| 8.2.2 | RL | Method 1 or 2 of
IEC 61300-3-6 | Wavelengths:
1 310 nm, 1 550 nm
and 1 625 nm | When straight cleaved:
$\geq 35$ dB (grade 3)
$\geq 45$ dB (grade 2)
When angle cleaved:
$\geq 60$ dB (grade 1) | $\geq 60$ dB | +| 8.2.3 | Change in
attenuation
and RL | IEC 61300-3-3 | Monitored at
1 310 nm, 1 550 nm,
and 1 625 nm | Change in attenuation
$\leq \pm 0.2$ dB during and after
test
Meet the RL requirement
of the specified RL grade
in 8.2.2 during and after
the test | Change in attenuation
$\leq \pm 0.1$ dB during test
$\leq \pm 0.05$ dB after test
Meet the RL requirement
of the specified RL grade
in 8.2.2 during and after
the test | +| 8.2.4 | Vibration
(sinusoidal) | IEC 61300-2-1 | Sweep (10 Hz to
55 Hz to 10 Hz) at
1 oct/min
Amplitude 0.75 mm
Duration: 15 cycles
3 axes X-Y-Z | Meet the change in
attenuation and RL of
No. 8.2.3 during and after
the test | Meet the change in
attenuation and RL of
No. 8.2.3 during and after
the test | +| 8.2.5 | Shock | IEC 61300-2-9 | 5 000 m/s 2 (~500g)
1 ms pulse
3 axes X-Y-Z | Meet the change in
attenuation and RL of
No. 8.2.3 after the test | Meet the change in
attenuation and RL of
No. 8.2.3 after the test | +| 8.2.6 | Torsion | IEC 61300-2-5 | Load 2 N
–180 ° and +180 ° at
25 cm from splice
protector
Duration: 10 cycles | Meet the change in
attenuation and RL of
No. 8.2.3 during and after
the test | Meet the change in
attenuation and RL of
No. 8.2.3 during and after
the test | +| 8.2.7 | Fibre
retention | IEC 61300-2-4 | Load:
2 N primary
5 N secondary
at 30 cm from splice
protector
Duration: 60 s | Meet the change in
attenuation and RL of
No. 8.2.3 during and after
the test | Meet the change in
attenuation and RL of
No. 8.2.3 during and after
the test | +| 8.2.8 | Bending
moment | IEC 61300-2-7 | Load: 2 N in middle
of splice protector for
10 s | Meet the change in
attenuation and RL of
No. 8.2.3 after the test | Meet the change in
attenuation and RL of
No. 8.2.3 after the test | +| 8.2.9 | Cold (Note 2) | IEC 61300-2-17 | –40°C, 96 h | Meet the change in
attenuation and RL of
No. 8.2.3 during and after
the test | Meet the change in
attenuation and RL of
No. 8.2.3 during and after
the test | + +**Table 1 – Performance requirements for single-mode fibre splices** + +| No | Test | Method | Test severities | Mechanical splice | Fusion splice with protector | +|--------|--------------------------------------------|----------------|------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------|--------------------------------------------------------------------------------| +| 8.2.10 | Dry heat (Note 2) | IEC 61300-2-18 | +70°C, 96 h | Meet the change in attenuation and RL of No. 8.2.3 during and after the test | Meet the change in attenuation and RL of No. 8.2.3 during and after the test | +| 8.2.11 | Composite temperature/humidity cyclic test | IEC 61300-2-21 | –10°C/+65°C
>93% RH at maximum temperature
Dwell time at extreme temperatures: 3 h (24 h/cycle)
Duration: 10 cycles | Meet the change in attenuation and RL of No. 8.2.3 during and after the test | Meet the change in attenuation and RL of No. 8.2.3 during and after the test | +| 8.2.12 | Change of temperature | IEC 61300-2-22 | –40°C and +70°C
Dwell time at extreme temperatures: 1 h
Rate of change: 1°C/min
Duration: 12 cycles | Meet the change in attenuation and RL of No. 8.2.3 during and after the test | Meet the change in attenuation and RL of No. 8.2.3 during and after the test | +| 8.2.13 | Dust – Laminar flow | IEC 61300-2-27 | <150 µm
25 g/m 3
Duration: 10 min | Meet the change in attenuation and RL of No. 8.2.3 after the test | Not applicable (as no dust can come into the optical path of the fused fibres) | +| 8.2.14 | Salt mist (Note 1) | IEC 61300-2-26 | 50 g/l NaCl solution of pH 6.5 to 7.2 at 35°C for 96 h | No visual evidence of corrosion | No visual evidence of corrosion | +| 8.2.15 | Water immersion (Note 3) | IEC 61300-2-45 | Between 1 cm and 5 cm below the surface of the water at +45°C
Duration: 1 cycle of 7 days | Meet the change in attenuation and RL of No. 8.2.3 during and after the test | Meet the change in attenuation and RL of No. 8.2.3 during and after the test | + +NOTE 1 – Only recommended when the splice or splice protector contains metallic component(s). + +NOTE 2 – Cold and dry heat optional as temperature effects are already assessed during the change of temperature test (No. 8.2.12). + +NOTE 3 – Only recommended for splices that may be subject to occasional immersion in water, e.g., due to flooding of pedestals, basements or vaults. To be agreed between supplier and customer. + +### 8.3 Validation of the splicing procedure + +For the validation of the splicing procedure, the fibre splices are made on the same optical fibre or ribbon. At least 100 splices should be made to check the requirements of test Nos 8.3.1 and 8.3.2 in Table 2. + +NOTE – 100 Splices are needed to obtain a reliable distribution of the optical performance of the splices. This corresponds to the installation tests specified in [b-IEC 61753-131-03], [b-EN 50411-3-2] and [b-EN 50411-3-3]. + +**Table 2 – Requirements for validation of splicing procedure of single-mode fibre splices** + +| No | Test | Method | Test severities | Mechanical splice | Fusion splice without protector | +|-------|----------------|--------------------------------|----------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 8.3.1 | Attenuation/IL | IEC 61300-3-4 | Wavelengths:
1 310 nm, 1 550 nm
and 1 625 nm | Single fibre and ribbon fibre splices:
– Grade B
$\leq 0.12$ dB average
$\leq 0.25$ dB in 97% of the splices
– Grade C
$\leq 0.25$ dB average
$\leq 0.5$ dB in 97% of the splices | Splices on single fibres made by:
– Active core alignment:
$\leq 0.05$ dB average
$\leq 0.1$ dB in 97% of the splices
– Active cladding alignment:
$\leq 0.1$ dB average
$\leq 0.2$ dB in 97% of the splices
Splices on ribbon fibres made by:
– Passive alignment by V-groove:
$\leq 0.1$ dB average
$\leq 0.2$ dB in 97% of the splices | +| 8.3.2 | RL | IEC 61300-3-6
method 1 or 2 | Wavelengths:
1 310 nm, 1 550 nm
and 1 625 nm | When straight cleaved:
$\geq 35$ dB (grade 3)
$\geq 45$ dB (grade 2)
When angle cleaved:
$\geq 60$ dB (grade 1) | $\geq 60$ dB for all splices | + +### 8.4 Performance characteristics for multimode fibre splices + +Splicing of multimode fibres with cladding alignment provides sufficient attenuation performance since multimode fibre has a relatively large core diameter compared with a single-mode fibre. Detailed performance criteria need further study since the attenuation of the splice depends not only on splicing conditions, but also on measurement conditions such as the modal power launch conditions. + +NOTE – The tests and test severities should correspond with [b-IEC 61753-1] and [b-EN 50411-3-6]. + +## Appendix I + +### Index of refraction matching materials for mechanical optical fibre splices + +(This appendix does not form an integral part of this Recommendation.) + +The most common index-matching materials are silicon gels and silicon greases. UV-curable adhesives and epoxy resins are also sometimes used as matching materials. + +Gels and greases are used more often because they provide superior strain relief and viscoelasticity in the fibre-to-fibre gap. This allows them to accommodate differential thermal expansion and mechanical stresses without causing delamination in the gap or inducing excessive stress in the fibre. + +Curing silicone gels, UV-curable adhesives and epoxy resins are cross-linked, cured materials. As such, they are chemically active until they are cured and they have limited shelf life in their uncured state (6 months is typical). Curing gels must be cured at the time of splicing by means of mixing two component fluids or by exposure of an uncured fluid to elevated temperature. They should be chemically and physically stable once cured. + +Non-curing silicone and other greases are suspensions of a microscopic powder thickener in an optical fluid and are sometimes also called gels, optical coupling compounds or optical couplants. They are non-curing, ready-to-use, single component materials, with no intrinsic shelf-life limit due to cure reaction components. Their physical consistency is that of a grease – while they will flow from a dispensing syringe under pressure, they do not migrate when at rest in the fibre splice. + +Most pre-index-matched mechanical splices use non-curing index-matching grease. Some optical greases have been shown to separate into their constituent fluid and thickener after long periods at elevated temperature (so called oil separation). Some materials have exhibited a tendency to dry out over many months or to evolve gas micro-bubbles that introduce a hazy appearance (so called evaporation or appearance). If the materials are not properly filtered, de-aerated and packaged they contain entrained microscopic air bubbles, dust, fibres and other particles that can degrade RL and IL in the splice (so called colour, appearance or particulate contamination). The long-term environmental stability of index-matching greases should be confirmed before use in applications with a wide temperature range, or other severe or unusual environmental conditions. Lot test requirements for these materials is recommended as shown in Table I.1. Other requirements should be added to suit the particular splice design and environmental conditions. + +**Table I.1 – Recommended specifications for index-matching greases in fibre splices** + +| Property | Method | Requirement | +|----------------------------------|-----------------------------------------------|--------------------------------------------------------------------------------------| +| Colour | Visual | Water white, non-yellowing | +| Appearance | Visual | No bubbles, voids or visible particles | +| Refractive index at 25°C, 589 nm | See [b-ASTM D1218-21] | $1.463 \pm 0.003$ (for silica fibre) | +| Evaporation, 24 h at 100°C | See [b-ASTM D972-16] | 0.2%, max | +| Oil separation, 24 h at 100°C | See FTM 791, method 321.2 of [b-FED-STD-791C] | 0.2%, max | +| Particulate contamination | See FTM 791B, method 3005 of [b-FED-STD-791C] | <300 particles/cm 3 , diameter 10 µm to 34 µm
No particles above 35 µm | + +## Appendix II + +### Optical fibre splice attenuation with different types of fibres + +(This appendix does not form an integral part of this Recommendation.) + +The optical performance of the fusion splices described in clause 8 are specified when the splices were made with identical fibres. + +In reality, the splices are made between different fibres with different MFDs, core-cladding concentricity and cladding diameter. + +The relationship between the splice loss and these fibre parameters is given by the equation: + +$$Loss (dB) = -10 \log_{10} \left[ \frac{(2 \cdot \omega_1 \cdot \omega_2)^2}{(\omega_1^2 + \omega_2^2)^2} \cdot \exp \left\{ \frac{-2 \cdot d^2}{\omega_1^2 + \omega_2^2} - 2 \cdot \pi^2 \cdot \frac{n_0^2}{\lambda^2} \cdot \frac{(\omega_1^2 \cdot \omega_2^2)}{(\omega_1^2 + \omega_2^2)} \cdot \sin^2(\theta) \right\} \right]$$ + +**Mode field diameter mismatch factor**      **Core lateral offset factor**      **Fibre axis angle offset factor** + +where + +$\omega_1$ = mode field radius of transmit fibre + +$\omega_2$ = mode field radius of receive fibre + +$d$ = lateral displacement of cores + +$\lambda$ = wavelength of transmitted light + +$n_0$ = index of refraction + +$\theta$ = angular misalignment of fibre axes. + +The factor related to the MFD mismatch is often the largest contributor to the splice loss. When using identical fibres, the loss contribution caused by the MFD mismatch becomes minimal. + +The factor related to the core offset is related to the core-cladding concentricity and cladding diameter differences. Fusion splice machines with active core alignment minimize the core offset and therefore reduce the loss contribution related to core offset. Fusion splicing machines using active cladding alignment do not take the differences of core-cladding concentricity into account and therefore give slightly higher splice losses compared to the active core alignment method. Finally, fusion splicing machines using a passive V-groove alignment system are subject to both core-cladding concentricity differences and cladding diameter difference. + +The factor containing the fibre axis offset angle $\theta$ is most of the time negligible, unless there is contamination on the cladding that will misalign the fibre in the fibre clamping mechanism. + +The values in Tables II.1, II.2 and II.3 were obtained by a Monte Carlo simulation. The assumption was made that the distributions of MFD, core-cladding concentricity and cladding diameter were Gaussian and following values for the nominal and the standard deviations on the nominal values were used: + +- MFD: nominal values 8.6 µm, 9.2 µm and 12.5 µm, standard deviation 0.10 µm; +- core-cladding concentricity error: nominal value 0.2 µm, standard deviation 0.07 µm; +- cladding diameter: nominal value 125.0 µm, standard deviation 0.15 µm. + +For fusion splicing equipment with active core alignment, the effects of the core-cladding concentricity and cladding diameter are considered to be minimal. Table II.1 shows the loss contribution of fusion splices between single-mode fibres with various MFD ranges. + +**Table II.1 – Contribution of mode field diameter mismatch to splice loss of single-mode fibre splices with active core alignment** + +| Nominal MFD fibre No. 1 | Nominal MFD fibre No. 2 | Average splice loss increase | Maximum splice loss increase (99.9%) | +|--------------------------------|--------------------------------|-------------------------------------|---------------------------------------------| +| 9.2 µm | 9.2 µm | 0.001 dB | 0.012 dB | +| 9.2 µm | 8.6 µm | 0.021 dB | 0.060 dB | +| 9.2 µm | 12.5 µm | 0.403 dB | 0.519 dB | +| 8.6 µm | 12.5 µm | 0.594 dB | 0.725 dB | + +Table II.2 shows the loss contributions of the MFD mismatch and the core-cladding concentricity when using fusion splicing techniques with active cladding alignment. + +**Table II.2 – Contribution of mode field diameter mismatch and core-cladding concentricity to splice loss of single-mode fibre splices with active cladding alignment.** + +| Nominal MFD fibre No. 1
with maximum
core-cladding
concentricity error
0.5 µm | Nominal MFD fibre No. 2
with maximum
core-cladding
concentricity error
0.5 µm | Average splice loss increase | Maximum splice loss increase (99.9%) | +|------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------|-------------------------------------|---------------------------------------------| +| 9.2 µm | 9.2 µm | 0.019 dB | 0.085 dB | +| 9.2 µm | 8.6 µm | 0.040 dB | 0.115 dB | +| 9.2 µm | 12.5 µm | 0.415 dB | 0.540 dB | +| 8.6 µm | 12.5 µm | 0.608 dB | 0.745 dB | + +Table II.3 shows the loss contributions of the core-cladding concentricity and cladding diameter when using fusion splice techniques with V-groove alignment (V-groove angle 90°). + +**Table II.3 – Contribution of mode field diameter mismatch, core-cladding concentricity and cladding diameter to splice loss of single-mode fibre splices with passive V-groove alignment** + +| Nominal MFD fibre No. 1
with maximum
core-cladding
concentricity error 0.5 µm
and nominal cladding
diameter 125.0 µm | Nominal MFD fibre No. 2
with maximum
core-cladding
concentricity error 0.5 µm
and nominal cladding
diameter 125.0 µm | Average splice loss increase | Maximum splice loss increase (99.9%) | +|-------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------|---------------------------------------------| +| 9.2 µm | 9.2 µm | 0.024 dB | 0.145 dB | +| 9.2 µm | 8.6 µm | 0.045 dB | 0.175 dB | +| 9.2 µm | 12.5 µm | 0.419 dB | 0.550 dB | +| 8.6 µm | 12.5 µm | 0.611 dB | 0.745 dB | + +## Appendix III + +### Fibre imaging in fusion splicing machines + +(This appendix does not form an integral part of this Recommendation.) + +The imaging process of optical fibres during fusion splice is an important component both for fibre alignment and loss estimation. When performing loss estimation, the goal of the fibre imaging system is to determine the refractive index geometry in the vicinity of the splice point, while for fibre alignment in preparation for fusion splicing, the goal of the fibre imaging system is to determine the relative position and orientation of the fibre tips. + +The fibre imaging systems embedded in commercial fusion splice machines generally consist of illumination sources, objective lenses and cameras, providing magnified transverse imaging of optical fibre. The light-emitting diode is the most used illumination source due to its monochromatic illumination. The objective lens is used to capture and focus an image, and the camera could be a charge-coupled device or complementary metal oxide semiconductor, digitizing the final fibre image. The fibre imaging system usually utilizes two orthogonal imaging paths or incorporates lenses and mirrors to observe the fibre from two perpendicular directions. Figure III.1 provides two typical schematics of orthogonal fibre imaging system, of which Figure III.1-a is for single fibre comprising two orthogonal paths and Figure III.1-b is for ribbon, using two illumination sources, lenses and cameras with a movable mirror. Note that each fibre in a ribbon has a slightly different distance to the objective lens, such a defocusing effect can be compensated for by utilizing a special objective lens. + +![Schematic diagrams of typical orthogonal imaging systems for single fibre and ribbon.](d9c0a780cd22626253dab4aa41699e2f_img.jpg) + +The diagram consists of two parts, (a) and (b), illustrating different fibre imaging configurations. Part (a) shows a single fibre with two orthogonal imaging paths. Two objective lenses and cameras are positioned at 90-degree angles to each other, both pointing towards the fibre. Two illumination sources are also positioned at 90-degree angles to each other, providing light from different directions. Part (b) shows a ribbon of fibres. A vertical mirror is positioned to the left of the ribbon. Two objective lenses and cameras are positioned at 90-degree angles to each other, both pointing towards the ribbon. Two illumination sources are positioned at 90-degree angles to each other, providing light from different directions. A legend on the right side of the diagram identifies the components: 'Illumination source' (represented by a small circle with a light bulb icon), 'Objective lens and camera' (represented by a trapezoidal shape), and 'Light path' (represented by an arrow). + +Schematic diagrams of typical orthogonal imaging systems for single fibre and ribbon. + +**Figure III.1 – Schematic diagrams of typical orthogonal imaging systems: +a – single fibre; b – ribbon** + +When imaged transversely, the fibre cladding exhibits a wide bright band positioned in the centre sandwiched by two dark bands, and the curved surface of the fibre magnifies the core region making the core appears out of proportion to the cladding diameter. The refractive index profile geometry of the optical fibre determines how it interacts with the illumination rays during fibre imaging. Snell's law can be used to trace the trajectory of illumination rays as they pass through the optical fibre. Figure III.2 gives a simple trace model of illumination rays that is helpful for understanding the transverse fibre image. The rays incident to the centre region exhibit a straighter trajectory than those incident at more oblique angles, and the rays far from the core region (shown as the shaded region in Figure III.2) are refracted so strongly that they are not captured by the objective lens, resulting in dark + +sections in the fibre image. No information about the shaded regions can be obtained from fibre image; however, this is usually not a problem since mostly the core region or the edge of cladding is important for fibre alignment or loss estimation. + +Note that for most optical fibres, the cladding surface is a perfect cylinder, and as the wavelength of light inside the fibre is reduced in scale by an amount equal to the cladding refractive index, the core region is magnified when compared to other portions of the image. The magnification is equal to the refractive index of the cladding. It also should be noted that the weak refractive index contrast between the core and cladding has a relatively small impact on the trajectory of illumination rays, so the core is nearly invisible when the objective lens is exactly focused on the fibre. The fibre image is usually defocused deliberately to make the core region distinct. + +![Figure III.2: Traces of illumination rays passing through an optical fibre. The diagram shows a cross-section of a fibre with a 'Core' and 'Cladding'. Light rays enter from the left, converge into the core, and then diverge as they exit the fibre. On the right, two images show the fibre's end face: the left one is in focus, showing only the cladding edge, while the right one is defocused, showing a bright central core region. Labels include 'Cladding', 'Core', and 'Regions of light captured by objective lens'. A small code 'L.400-L.12(22)_FIII.2' is in the bottom right corner.](05c9994c1f5daf53d0d9b107657d7a17_img.jpg) + +Figure III.2: Traces of illumination rays passing through an optical fibre. The diagram shows a cross-section of a fibre with a 'Core' and 'Cladding'. Light rays enter from the left, converge into the core, and then diverge as they exit the fibre. On the right, two images show the fibre's end face: the left one is in focus, showing only the cladding edge, while the right one is defocused, showing a bright central core region. Labels include 'Cladding', 'Core', and 'Regions of light captured by objective lens'. A small code 'L.400-L.12(22)\_FIII.2' is in the bottom right corner. + +**Figure III.2 – Traces of illumination rays passing through an optical fibre** + +When identical fibres make up a fusion splice, the fibre image position is uniform across the splice point under precise alignment of the two fibres, as indicated in Figure III.3-a. The refractive index profile of a fibre is the same as that of others, making it difficult to detect the position of splice point on the captured image. When different types of fibres are spliced together, e.g., G.652.D and G.654.E, a distinct vertical line shows up at the position of a splice point, as indicated in Figure III.3-b. This comes from the lateral refraction of illumination rays occurring at the splice point where the refractive index has a transverse difference. Since the refractive index of G.652.D fibre is higher than that of the G.654.E type, illumination rays are refracted towards the direction of the G.652.D fibre, resulting in a bright line on this side, while leaving a dark line on the G.654.E side. It should be noted that this vertical line caused by lateral refraction does not affect the light travelling along the core. When performing fusion splice on different types of fibres with distinct refractive index profiles, the test methods for splice loss in documents of the IEC 61300 series can be adopted to examine the quality of splice point if needed. + +![Microscopic image of a splice point between two identical G.652.D fibers.](ae02603e9e4b46477222bf72c1c7c7f6_img.jpg) + +A grayscale micrograph showing a splice point between two identical G.652.D optical fibers. The fibers are aligned horizontally, and the splice point is visible as a continuous, seamless transition between the two segments. The labels "G.652.D" are present at the bottom of each fiber segment. + +Microscopic image of a splice point between two identical G.652.D fibers. + +(a) + +![Microscopic image of a splice point between a G.652.D fiber and a G.654.E fiber.](56a7fc5964ed9463fa47ca8a60568dec_img.jpg) + +A grayscale micrograph showing a splice point between a G.652.D optical fiber and a G.654.E optical fiber. The fibers are aligned horizontally, and the splice point is visible as a distinct vertical line separating the two segments. The labels "G.652.D" and "G.654.E" are present at the bottom of the respective fiber segments. + +Microscopic image of a splice point between a G.652.D fiber and a G.654.E fiber. + +(b) + +**Figure III.3 – Image of splice point: a-identical G.652.D fibres; b-G.652.D and G.654.E fibres** + +## Bibliography + +- [b-ITU-T G.671] Recommendation ITU-T G.671 (2019), *Transmission characteristics of optical components and subsystems*. +- [b-ITU-T TR-OFCS] ITU-T Technical Report TR-OFCS (2015), *Optical fibres, cables and systems*. +- [b-IEC 61753-1] International Standard IEC 61753-1:2018 + AMD1:2020, *Fibre optic interconnecting devices and passive components – Performance standard – Part 1: General and guidance*. +- [b-IEC 61753-131-03] International Standard IEC 61753-131-03:2021, *Fibre optic interconnecting devices and passive components – Performance standard – Part 131-03: Single-mode mechanical fibre splice for category OP – Outdoor protected environment*. +- [b-IEC TR 62000] Technical Report IEC TR 62000:2021, *Guidelines for combining different single-mode fibre sub-categories*. +- [b-IEC TR 62316] Technical Report IEC TR 62316:2017, *Guidance for the interpretation of OTDR backscattering traces for single-mode fibres*. +- [b-EN 50411-3-2] EN 50411-3-2:2021, *Fibre organisers and closures to be used in optical fibre communication systems – Product specifications – Part 3-2: Singlemode mechanical fibre splice*. +- [b-EN 50411-3-3] EN 50411-3-3:2019, *Fibre management systems and protective housings to be used in optical fibre communication systems – Product specifications – Part 3-3: Singlemode optical fibre fusion splice protectors*. +- [b-EN 50411-3-6] EN 50411-3-6:2022, *Fibre management systems and protective housings to be used in optical fibre communication systems – Product specifications – Part 3-6: Multi-mode mechanical fibre splice*. +- [b-ASTM D972-16] ASTM D972-16, *Standard test method for evaporation loss of lubricating greases and oils*. +- [b-ASTM D1218-21] ASTM D1218-21, *Standard test method for refractive index and refractive dispersion of hydrocarbon liquids*. +- [b-FED-STD-791C] Federal Test Method Standard FED-STD-791C (1986),2 *Lubricants, liquid fuels, and related products; Methods of testing*. + +--- + +2 Superseded. + +## ITU-T L-SERIES RECOMMENDATIONS + +## **ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT** + +| | | +|--------------------------------------------------------|---------------| +| OPTICAL FIBRE CABLES | | +| Cable structure and characteristics | L.100–L.124 | +| Cable evaluation | L.125–L.149 | +| Guidance and installation technique | L.150–L.199 | +| OPTICAL INFRASTRUCTURES | | +| Infrastructure including node elements (except cables) | L.200–L.249 | +| General aspects and network design | L.250–L.299 | +| MAINTENANCE AND OPERATION | | +| Optical fibre cable maintenance | L.300–L.329 | +| Infrastructure maintenance | L.330–L.349 | +| Operation support and infrastructure management | L.350–L.379 | +| Disaster management | L.380–L.399 | +| PASSIVE OPTICAL DEVICES | L.400–L.429 | +| MARINIZED TERRESTRIAL CABLES | L.430–L.449 | +| E-WASTE AND CIRCULAR ECONOMY | L.1000–L.1199 | +| POWER FEEDING AND ENERGY STORAGE | L.1200–L.1299 | +| ENERGY EFFICIENCY, SMART ENERGY AND GREEN DATA CENTRES | L.1300–L.1399 | +| ASSESSMENT METHODOLOGIES OF ICTS AND CO2 TRAJECTORIES | L.1400–L.1499 | +| ADAPTATION TO CLIMATE CHANGE | L.1500–L.1599 | +| LOW COST SUSTAINABLE INFRASTRUCTURE | L.1700–L.1799 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.404-201708-I_PDF-E/14a22f23ced8ba1d63ece69861dbaacc_img.jpg b/marked/L/T-REC-L.404-201708-I_PDF-E/14a22f23ced8ba1d63ece69861dbaacc_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..bd7c24e83d75a6b1baa7fb4210f76345166390c9 --- 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Telecommunication Union (ITU) features a globe with a lightning bolt superimposed on it, and the letters 'ITU' written across the center. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.41** + +(05/2000) + +SERIES L: CONSTRUCTION, INSTALLATION AND +PROTECTION OF CABLES AND OTHER ELEMENTS OF +OUTSIDE PLANT + +--- + +**Maintenance wavelength on fibres carrying +signals** + +ITU-T Recommendation L.41 + +(Formerly CCITT Recommendation) + +--- + +# **Maintenance wavelength on fibres carrying signals** + +## **Summary** + +This ITU-T Recommendation assigns the wavelengths for fibre identification, fault location and maintenance monitoring that may be used to manage the physical plant. The maintenance wavelength assignment has a close relationship with the transmission wavelength assignment selected by Study Group 15. + +## **Source** + +ITU-T Recommendation L.41 was prepared by ITU-T Study Group 6 (1997-2000) and approved under the WTSC Resolution 1 procedure on 12 May 2000. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSC Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2001 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +| | Page | +|-----------------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 In-service maintenance ..... | 1 | +| Appendix I – Remarks on the way for in-service maintenance of optical fibres ..... | 2 | +| Appendix II – Japanese consideration for selecting maintenance wavelength ..... | 2 | +| II.1 Present Japanese maintenance wavelength..... | 2 | +| II.2 Reason..... | 3 | +| II.2.1 Laser diode (LD) market..... | 3 | +| II.2.2 Filter..... | 3 | +| II.2.3 Fibre identification ..... | 3 | +| II.3 Direction for the future ..... | 4 | +| II.3.1 LD market..... | 4 | +| II.3.2 Filter..... | 4 | +| II.3.3 Fibre identification and handling..... | 4 | +| II.4 Result ..... | 5 | +| Appendix III – Information of bending loss for considering the wavelength assigned..... | 5 | + +## ITU-T Recommendation L.41 + +## Maintenance wavelength on fibres carrying signals + +## 1 Scope + +This ITU-T Recommendation deals with maintenance wavelength on fibres carrying signals without in-line optical amplifiers. + +ITU-T Recommendation L.25 "*Optical fibre cable network maintenance*" defines comprehensive guidelines to maintain optical fibre and suitable wavelength should be used for preventive maintenance as defined by this Recommendation. + +Maintenance systems which use wavelengths in a vacant window of optical fibre carrying signals are being operated currently and it should be taken into account that in-service maintenance of optical fibre should not interfere with the normal operation and expected performance of the information channels. + +## 2 In-service maintenance + +In-service maintenance of optical fibre should be done in such a way that it does not interfere with the normal operation and expected performance of the information channels. Wavelength for in-service maintenance, as shown in Table 1, should be used. + +**Table 1/L.41 – Maintenance wavelength assignment** + +| | 1310 nm-window | 1550 nm-window | 1625 nm-window b) | 1650 nm-window a), b) | +|---------------|-----------------------|-----------------------|------------------------------|----------------------------------| +| Case 1 | Active | Vacant or maintenance | Vacant or maintenance | Vacant or maintenance | +| Case 2 | Vacant or maintenance | Active | Vacant or maintenance | Vacant or maintenance | +| Case 3 | Active | Active | Vacant or maintenance | Vacant or maintenance | +| Case 4 | Active or vacant | Active | Active | Vacant or Maintenance | + +a) When there is no optical light (nominally below –60 dBm) from the OTDR laser at all wavelengths equal to or below the maximum client signal wavelength (see Case 4) at the point "R", it is not necessary to consider interference with transmission. + +b) These OTDR wavelengths are suitable only for systems with client signals at wavelengths less than 1565 nm. Applicability for client signals at longer wavelength is under study. + +**Case 1:** This usually applies to single mode fibre. Transmission system uses only 1310 nm-window. + +**Case 2:** This usually applies to dispersion shifted fibre. Transmission system uses only 1550 nm-window. + +**Case 3:** This usually applies to single mode fibre. Transmission system uses two or more wavelengths in 1310 nm-window and 1550 nm-window. + +**Case 4:** The maximum transmission wavelength is under study in Study Group 15, but is limited to less than or equal to 1625 nm. + +Wavelength is independent of types of fibre (single mode fibre or dispersion shifted fibre). + +## APPENDIX I + +### Remarks on the way for in-service maintenance of optical fibres + +**Loss:** The optical interfaces are defined at points S (source) and R (receive). Point of presence should be after the point S and before the point R, therefore, the coupling/filtering function loss will be counted as part of the physical plant. + +**Receive cross-talk:** Even with filtering, the special characteristics of the light source from maintenance equipment are broad enough to allow the possibility of cross-talk or other similar impairment to the service bearing signals. The combination of its spectral characteristic and filter requirements might well be best limited by a requirement to the effect of: the total amount of residual optical power at point R shall be less than –XX dBm at all wavelengths below the maximum operating wavelength of YY. + +**Average optical power:** For the time intervals during which OTDR pulses are present, it will contribute to the effective average optical power. It is presumed, but should be verified, that the OTDR contribution to the total is low enough to avoid concerns about fibre non-linearities, safety concerns, or error detection circuits. + +Items should correspond with transmission systems characteristics: + +- Optical characteristics of light sources from maintenance equipment (power, wavelength, FWHM of its spectrum, modulation frequency of the light source, OTDR's pulsewidth and repetition cycle). +- Allowing for light power at points R and S. + +## APPENDIX II + +### Japanese consideration for selecting maintenance wavelength + +### II.1 Present Japanese maintenance wavelength + +**Trunk networks:** + +| | Communication | Maintenance | +|---------------|--------------------------------|----------------------------------------------------------------------------------------------------------| +| Case A | 1310 nm | 1550 nm | +| Case B | 1550 nm
(Distance < 80 km) | 1310 nm (Testing and monitoring)
1650 nm (Fibre identification) | +| Case C | 1550 nm
(Distance < 160 km) | 1550 nm (Testing for post-fault and after installation)
1650 nm (Fibre identification and monitoring) | + +#### Access networks: + +| | Communication | Maintenance | +|--------|---------------------|-------------| +| Case D | 1310 nm | 1550 nm | +| Case E | 1310 nm and 1550 nm | 1650 nm | + +### II.2 Reason + +#### II.2.1 Laser diode (LD) market + +1310 nm and 1550 nm LD markets are big while for other LDs the market is small. Because a lot of transmission systems use 1310 nm or 1550 nm LD, the use of 1310 nm or 1550 nm wavelength for optical fibre maintenance support systems would be economical. + +#### II.2.2 Filter + +In cases A, B and D, the wavelength difference between communication light and maintenance light is 240 nm. Filters have the characteristics as shown in Figure II.1. There is no problem for insulation. Transmission systems use 1310 nm or 1550 nm wavelength. Therefore, the 1550 nm or 1310 nm wavelength for optical fibre maintenance should be used, except fibre identification. + +In cases C and E, we need 70-100 nm wavelength differences at least, according to the filter characteristics. For manufacturing, we had better keep the difference 100 nm. In these cases, the popular type specification of the insulation loss is 30 dB. And that of the cheapest type is 20 dB. + +![Graph showing Insertion loss (Y-axis, 15 to 50 dB) versus Wavelength (X-axis, 1310 to 1650 nm). Two filter curves are shown: 'Filter for 1310 nm transmission' and 'Filter for 1550 nm transmission'. The 1310 nm filter has a low insertion loss at 1310 nm and a high insertion loss at 1550 nm. The 1550 nm filter has a low insertion loss at 1550 nm and a high insertion loss at 1310 nm.](023b142f90e1253702ac88b18380d3ec_img.jpg) + +The graph illustrates the insertion loss of two optical filters across a range of wavelengths. The Y-axis represents 'Insertion loss' in dB, with marked values at 15, 30, and 50. The X-axis represents 'Wavelength' in nm, with marked values at 1310, 1550, and 1650. Two curves are plotted: one for a 'Filter for 1310 nm transmission' and another for a 'Filter for 1550 nm transmission'. The 1310 nm filter shows a sharp increase in insertion loss starting around 1400 nm, reaching a plateau of approximately 50 dB by 1550 nm. The 1550 nm filter shows a sharp increase in insertion loss starting around 1600 nm, reaching a plateau of approximately 50 dB by 1650 nm. Both filters maintain a low insertion loss (below 15 dB) at their respective transmission wavelengths (1310 nm and 1550 nm). + +Graph showing Insertion loss (Y-axis, 15 to 50 dB) versus Wavelength (X-axis, 1310 to 1650 nm). Two filter curves are shown: 'Filter for 1310 nm transmission' and 'Filter for 1550 nm transmission'. The 1310 nm filter has a low insertion loss at 1310 nm and a high insertion loss at 1550 nm. The 1550 nm filter has a low insertion loss at 1550 nm and a high insertion loss at 1310 nm. + +Figure II.1/L.41 – Characteristics of filter + +There are a few LDs in a central office but a lot of filters are installed in front of ONU and OLT. Optical fibre maintenance support systems do not represent a big LD market. The LD market for wavelengths other than 1310 nm or 1550 nm is small, even if the optical fibre maintenance wavelength is recommended. When choosing the optical fibre maintenance wavelength, it is better to consider the filter specification in preference to LDs and transmission system specification for total system cost. Therefore, the 1650 nm wavelength should be chosen for cases C and E. + +#### II.2.3 Fibre identification + +A fibre is identified by bending. Fibre identification tools detect leaked maintenance light without interfering with the transmission. Therefore, the wavelength difference between the transmission light and the maintenance wavelength is necessary. + +In cases A, D and E, the insertion loss specification of the tool is less than 0.5 dB at 1310 nm and less than 2.5 dB at 1550 nm when the tool bends a fibre. In cases B and C, the loss specification is less than 0.5 dB at 1550 nm. + +### II.3 Direction for the future + +#### II.3.1 LD market + +Optical fibre maintenance support systems cannot represent a big market for LD so LDs, of wavelengths other than 1310 nm or 1550 nm, will remain in the minority in the future. + +#### II.3.2 Filter + +Fibre grating technique is under development. The fibre grating characteristics are shown in Figure II.2. If we get these characteristics, we do not need 100 nm-wavelength difference any longer. + +![Figure II.2/L.41 – Characteristics of grating. A graph showing Insertion loss (Y-axis, 0 to 50 dB) versus Wavelength (X-axis, 1310 nm to 1650 nm). The graph shows two rectangular pulses representing the grating characteristics. The first pulse is centered at 1550 nm with an insertion loss of 30 dB. The second pulse is centered at 1650 nm with an insertion loss of 30 dB. The baseline insertion loss is 0 dB.](7ff005f9556dc6518981bb92091d36ab_img.jpg) + +| Wavelength (nm) | Insertion loss (dB) | +|-----------------|---------------------| +| 1310 | 0 | +| 1550 | 30 | +| 1650 | 30 | + +Figure II.2/L.41 – Characteristics of grating. A graph showing Insertion loss (Y-axis, 0 to 50 dB) versus Wavelength (X-axis, 1310 nm to 1650 nm). The graph shows two rectangular pulses representing the grating characteristics. The first pulse is centered at 1550 nm with an insertion loss of 30 dB. The second pulse is centered at 1650 nm with an insertion loss of 30 dB. The baseline insertion loss is 0 dB. + +Figure II.2/L.41 – Characteristics of grating + +#### II.3.3 Fibre identification and handling + +If fibre gratings can be used, the wavelength differences between transmission light and maintenance light for fibre identification will be needed. Therefore, long wavelength should be used as much as possible. An optical fibre loss wavelength trace is shown in Figure II.3. According to this figure, 1650 nm wavelength is the longest wavelength. + +![Figure II.3/L.41 – Loss wavelength trace. A graph showing Loss (dB/km) (Y-axis, 0.2 to 0.6 dB/km) versus Wavelength (nm) (X-axis, 1200 nm to 1700 nm). The graph shows a line trace representing the loss wavelength trace. The loss starts at approximately 0.48 dB/km at 1200 nm, decreases to a minimum of about 0.21 dB/km at 1550 nm, and then increases to about 0.42 dB/km at 1700 nm.](f5e70cbe66e71e65b4ae4aa7816d266a_img.jpg) + +| Wavelength (nm) | Loss (dB/km) | +|-----------------|--------------| +| 1200 | 0.48 | +| 1300 | 0.35 | +| 1400 | 0.45 | +| 1500 | 0.25 | +| 1550 | 0.21 | +| 1600 | 0.22 | +| 1650 | 0.25 | +| 1700 | 0.42 | + +Figure II.3/L.41 – Loss wavelength trace. A graph showing Loss (dB/km) (Y-axis, 0.2 to 0.6 dB/km) versus Wavelength (nm) (X-axis, 1200 nm to 1700 nm). The graph shows a line trace representing the loss wavelength trace. The loss starts at approximately 0.48 dB/km at 1200 nm, decreases to a minimum of about 0.21 dB/km at 1550 nm, and then increases to about 0.42 dB/km at 1700 nm. + +Figure II.3/L.41 – Loss wavelength trace + +### II.4 Result + +Considering the filter specification and fibre identification, the longer the wavelength, the better. Considering the fibre characteristics, it would be preferable to use from 1310 nm to 1650 nm. So therefore, the 1650 nm wavelength would be used. + +## APPENDIX III + +### Information of bending loss for considering the wavelength assigned + +This ITU-T Recommendation shows optical fibre bending characteristics, which is an important element for assigning wavelength, based on Japanese experience. + +Optical fibre maintenance functions, especially fibre handling and fibre identification, are essential for maintaining fibres in the field. Operators have to handle fibres in central offices and manholes. They need to identify fibres with a clip-on power meter. The clip-on power meter has to bend a fibre in order to detect leaking identification light. The insertion loss specification of an existing tool for single mode fibres is less than 0.5 dB at 1310 nm and less than 2.5 dB at 1550 nm, when the tool bends a fibre. The loss specification of an existing tool for dispersion shifted fibres is less than 0.5 dB at 1550 nm. The handling loss is usually bigger than bending loss for identification. + +Figure III.1 shows the fibre general characteristics for bending. It shows that the longer the wavelength, the bigger the loss. So when long wavelength light is used for transmission, it is easy to change loss of fibre. Transmission systems have to be designed taking into consideration loss change. It is difficult to determine the value of loss change. At least 5 dB or more would be necessary for 1550 nm in the case of single mode fibre. + +![Three line graphs showing bending loss (dB) vs wavelength (nm) for different bending radii: 9.5 mm, 12.5 mm, and 16 mm. Each graph compares two fibre types: Cut off: 1.27 μm MFD: 9.72 μm (solid line with filled squares) and Cut off: 1.17 μm MFD: 9.43 μm (dashed line with open squares).](e8ff6e66c77a8e96203c9f8db8f0986f_img.jpg) + +| Bending Radius (mm) | Fibre Type | Bending Loss (dB) at Wavelength (nm) | | | +|---------------------|---------------------------------|--------------------------------------|---------|---------| +| | | 1310 nm | 1550 nm | 1650 nm | +| 9.5 | ■ Cut off: 1.27 μm MFD: 9.72 μm | 0.0 | 0.9 | 0.9 | +| | □ Cut off: 1.17 μm MFD: 9.43 μm | 0.0 | 7.0 | 29.8 | +| 12.5 | ■ Cut off: 1.27 μm MFD: 9.72 μm | 0.0 | 0.3 | 0.3 | +| | □ Cut off: 1.17 μm MFD: 9.43 μm | 0.0 | 1.9 | 5.6 | +| 16 | ■ Cut off: 1.27 μm MFD: 9.72 μm | 0.0 | 0.0 | 0.03 | +| | □ Cut off: 1.17 μm MFD: 9.43 μm | 0.0 | 0.25 | 1.27 | + +Legend: +■ Cut off: 1.27 μm MFD: 9.72 μm +□ Cut off: 1.17 μm MFD: 9.43 μm + +Three line graphs showing bending loss (dB) vs wavelength (nm) for different bending radii: 9.5 mm, 12.5 mm, and 16 mm. Each graph compares two fibre types: Cut off: 1.27 μm MFD: 9.72 μm (solid line with filled squares) and Cut off: 1.17 μm MFD: 9.43 μm (dashed line with open squares). + +T0604700-99 + +Figure III.1/L.41 – Bending characteristics + +## **SERIES OF ITU-T RECOMMENDATIONS** + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information 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sha256:52a289bbb49d106b16f646b5050f62e5c7cbe1bb201f8c767547c3039abbf359 +size 8245 diff --git a/marked/L/T-REC-L.54-200402-I_PDF-E/raw.md b/marked/L/T-REC-L.54-200402-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..5a6b19b2e2323d23fdb03b18e851b657a44fc2c7 --- /dev/null +++ b/marked/L/T-REC-L.54-200402-I_PDF-E/raw.md @@ -0,0 +1,484 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a lightning bolt striking across it, and the letters 'ITU' superimposed on the globe. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.54** + +(02/2004) + +SERIES L: CONSTRUCTION, INSTALLATION AND +PROTECTION OF CABLES AND OTHER ELEMENTS OF +OUTSIDE PLANT + +--- + +**Splice closure for marinized terrestrial cables +(MTC)** + +ITU-T Recommendation L.54 + +--- + + + +# **ITU-T Recommendation L.54** + +# **Splice closure for marinized terrestrial cables (MTC)** + +## **Summary** + +This Recommendation refers to both the design and the main characteristics that an underwater splice closure for MTC should have in order to be suitable for this application, as well as to guarantee the expected lifetime of the whole transmission link. + +This Recommendation provides the tests for characterization and evaluation of the underwater splice closures performance, including mechanical integrity and optical stability of the product simulating the effect of the environment (water), as well as interventions related to installation and network maintenance. + +## **Source** + +ITU-T Recommendation L.54 was approved on 6 February 2004 by ITU-T Study Group 6 (2001-2004) under the ITU-T Recommendation A.8 procedure. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2004 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +| | Page | +|---------------------------------------------------------------------------------|------| +| 1 Introduction ..... | 1 | +| 2 Scope ..... | 1 | +| 3 References..... | 1 | +| 4 Abbreviations and definitions..... | 2 | +| 5 Main characteristics ..... | 2 | +| 6 Qualification tests ..... | 3 | +| 7 Sample preparation ..... | 4 | +| 8 Reference measurements ..... | 4 | +| 9 Tests..... | 4 | +| 9.1 Temperature cycling..... | 5 | +| 9.2 Tensile with twist restrained..... | 5 | +| 9.3 Tensile with torque minimized..... | 6 | +| 9.4 Bending under tension (sheave passage)..... | 7 | +| 9.5 Repeated bending (optional)..... | 7 | +| 9.6 Hydraulic pressure resistance ..... | 8 | +| 9.7 Bumps..... | 8 | +| 9.8 Vibration..... | 9 | +| 9.9 Corrosion resistance (optional)..... | 9 | +| Appendix I – Examples of different closure designs available on the market..... | 10 | + + + +# Splice closure for marinized terrestrial cables (MTC) + +## 1 Introduction + +An important part of any installed underwater optical cable system is the jointing between different cable spans. + +In fact, it is very important that a splice closure utilized for an underwater (i.e., MTC) optical cable system is manufactured in order to guarantee not only a good quality of transmission during the expected lifetime, but also cost savings for maintenance purposes. + +A splice closure comprises a mechanical structure (closure housing) that is attached to the ends of two or more underwater cables, and a set of boxes (organizers) for containing and protecting the fibres and passive optical devices (if any). + +As a general rule, the closure housing and the armour terminations, generally designed for a whole MTC family, should be dimensioned for the strongest cable designed for that particular link (maximum tensile strength and maximum pressure resistance). + +Splice closures for MTC applications may contain fibre splices, mass splices and passive devices. + +Moreover, since such closures are typically mounted on the cable before it is installed, it should also be designed to withstand all handling and loads that occur during cable installation. + +## 2 Scope + +This Recommendation details: + +- the mechanical and environmental characteristics of splice closures for MTC applications; +- the main optical performances that such closures have to guarantee during their lifetimes. + +## 3 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- ITU-T Recommendation G.972 (2000), *Definition of terms relevant to optical fibre submarine cable systems*. +- ITU-T Recommendation G.976 (2000), *Test methods applicable to optical fibre submarine cable systems*. +- ITU-T Recommendation L.12 (2000), *Optical fibre joints*. +- ITU-T Recommendation L.13 (2003), *Performance requirements for passive optical nodes: Sealed closures for outdoor environments*. +- IEC 60068-2-6:1995, *Environmental testing – Part 2: Tests – Vibration (sinusoidal)*. +- IEC 60794-1-2:2003, *Optical fibre cables – Part 1-2: Generic specification – Basic optical cable test procedures (Methods:E1, E6, E7, E18A, F1, F10)*. + +- IEC 60794-3-30:2002, *Optical fibre cables – Part 3-30: Outdoor cables – Family specification for optical telecommunication cables for lake and river crossings.* +- IEC 61300-2-22:1995, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-22: Tests – Change of temperature.* +- IEC 61300-2-26:1995, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2-26: Tests – Salt mist.* +- IEC 61300-3-3:2003, *Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 3-3: Examinations and measurements – Active monitoring of changes in attenuation and return loss (multiple paths).* + +## 4 Abbreviations and definitions + +- **MTC** Marinized Terrestrial Cable (see definition in ITU-T Rec. G.972). +- **NOTS** Nominal Operating Tensile Strength (see definition in Appendix I/G.976). NOTS represents the maximum average operational tension during installation, recovery or repair. +- **NTTS** Nominal Transient Tensile Strength (see definition in Appendix I/G.976). NTTS represents the maximum transient or unexpected load that may be applied to the cable, and is normally limited to a percentage of the CBL (Cable Breaking Load) from a mechanical safety point of view. +- **NPTS** Nominal Permanent Tensile Strength (see definition in Appendix I/G.976). NPTS represents the maximum residual load, which may be permanently applied to the cable on the seabed after installation. +- **OTDR** Optical Time Domain Reflectometer. + +## 5 Main characteristics + +Hereinafter, a list of the main characteristics (optical, mechanical and environmental) for a splice closure for MTC applications is given. + +Even though such a list cannot be considered exhaustive due to particular environments and applications, it is intended to give the basic and essential guidance for a suitable characterization of the splice closure. + +Additional requirements can be agreed upon between Customer(s) and Manufacturer(s) to reflect local or special conditions. + +Moreover, test methods already standardized are also given where applicable. + +A splice closure for MTC applications is designed: + +- To restore the integrity of sheath, including mechanical continuity of strength members of MTC; +- To protect the fibres, fibre splices and optical devices, from the external environment (water) and unwanted handling; +- To provide proper storage of fibre splices, passive devices (if any) and excess of fibres; +- To resist corrosion; +- To prevent hydrogen effects; +- To allow re-intervention on cables and splices; +- To provide for electrical continuity, if required. + +Basic components of the splice closure are: + +- Jointing box with cable core holder and optical organizer; +- Corrosion-resistant jointing box housing (e.g., stainless steel); +- Suitable jointing box covering with high grade protection and insulation; +- Appropriate bend restrictor; +- Metallic sacrificial elements (optional). + +The splice closure shall be watertight in order to avoid fibres being exposed to water both during the operating lifetime, and during and after maintenance operations. Moreover, it shall be equipped to avoid the effect on fibres from hydrogen released by cable armouring. + +In case metallic sacrificial elements are present, much care should be taken in order to prevent induced loss on optical fibres from hydrogen evolution. + +The problem of hydrogen evolution is one that can lead to attenuation increases. It is normally solved by different engineering approaches, that shall be documented by the manufacturer. + +The splice/storage trays shall meet minimum bending diameter of fibres. + +NOTE – Information about the design of the closure housing and the organizer system, as well as the splicing of fibres can be found in ITU-T Recs L.13 and L.12, respectively. Splices should have an average loss less than 0.5 dB. The optical attenuation due to ageing should be less than 0.2 dB. The optical attenuation due to fibre coiling should be not more than 0.2 dB over the entire joint. Fibre bend radius should be greater than 25 mm and, where possible, greater than 30 mm. + +Other information on fibre handling and fibre identification for splicing at cable joints can be found in ITU-T Manual "Construction, installation, jointing and protection of optical fibre cables". + +Finally, examples of closures available on the market, patented by the most important world constructors can be found in Appendix I. + +## 6 Qualification tests + +The purpose of qualification tests is to verify the integrity of the splice closure during storage, transport, installation and service. The splice closure for MTC shall be qualified for use up to the maximum water depth of the link. + +Qualification tests are carried out as part of the development program so as to choose proper design and technology, to demonstrate that they adequately satisfy the performances, reliability and lifetime expectation of the system. + +Tests carried out by the manufacturer can be considered adequate and therefore taken into consideration. An evaluation test program shall be agreed between Manufacturer and Customer. + +Depending on a particular application and upon agreement between Customer and Manufacturer, the test qualification program may be limited to some of the tests hereunder listed. + +For each test description, where applicable, the reference to the corresponding international standard is also reported. + +NOTE 1 – The tests described in this Recommendation shall assess functionalities and performances of the splice closures. Moreover, in order to guarantee the operating lifetime of splice closures, long-term ageing tests and failure effects, on materials and accessories of closures, could be necessary. + +NOTE 2 – The parameters specified in this Recommendation may be affected by measurement uncertainty arising either from measurement errors, or calibration errors due to a lack of suitable standards. Acceptance criteria shall be interpreted with respect to this consideration. The total uncertainty of measurement for this Recommendation shall be less than or equal to 0.05 dB for attenuation. The expression of "no change in attenuation" means that any change in measurement value, either positive or negative, within the uncertainty of measurement shall be ignored. + +## 7 Sample preparation + +The splice closure shall be connected between two specimen cables used in the link in accordance with assembly and disassembly procedures given by the manufacturer. + +Depending on specific tests, different cable lengths (specimen) may be connected to the splice closure. + +Moreover, depending on the topology and criticality of the link, a different number of samples can be accordingly defined between the Customer(s) and the Manufacturer(s). + +## 8 Reference measurements + +Prior to the tests, optical attenuation, electrical continuity of the metallic sheath and the insulation resistance between metallic tube and steel armour wires shall be measured for reference. + +The optical fibres may be spliced in loop(s) in order to achieve the desired accuracy in attenuation measurement. + +Optical attenuation measurements shall be performed at the wavelength of 1550 nm. Evaluation at 1625 nm is under consideration. + +The evaluation of optical attenuation of fibres and splices shall be performed either with the transmitter power technique or with the backscattering technique as described in IEC 61300-3-3, Part 3-3. + +The electrical insulation resistance shall be performed at 500 V DC. The detected value should be approximately equal to the insulation resistance of the cable as stated in its type-approval certificate. + +Moreover, the electrical continuity measurement of the metallic sheath should give a resistance value across the closure of around 0.2 Ohm. + +## 9 Tests + +The tests should be done in the following sequences, unless otherwise agreed between the Customer and the Manufacturer. + +The expression of "no significant change in attenuation" means that any change in measurement value, either positive or negative, within the uncertainty of measurement shall be ignored. + +**Sample 1, 2, 3 and 4** + +| Sample | First test | Second test | Third test | Fourth test | +|----------|----------------------|------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------|-------------| +| Sample 1 | Temperature cycling | Tensile with twist restrained | none | none | +| Sample 2 | Temperature cycling | Tensile with torque minimized | Repeated bending
NOTE – For practical reasons shorter pieces of cables can be used. | Bumps | +| Sample 3 | Temperature cycling | Bending under tension
NOTE – Shorter (about 50 m) pieces of cables can be jointed to the closure. | Hydraulic pressure resistance | Vibration | +| Sample 4 | Corrosion resistance | none | none | none | + +### 9.1 Temperature cycling + +#### Objectives + +- To prove that the optical characteristics of the closure are not modified by storage, transportation and service temperature ranges; +- To determine any specific storage or transportation requirements to ensure the above. + +International standard 7.2.1.3/G.976; IEC 60794-1-2, Method F1; IEC 61300-2-22. + +Sample preparation The splice closure shall be connected between two samples of cable used in the link of approximately 100 m long, in accordance with assembly and disassembly procedures given by the manufacturer. The fibres of the two cable-free ends shall be spliced in loop(s) for connection to measurement apparatus. + +Test conditions *Temperature cycle*: 1 cycle of 24 hours (6 hours at each temperature step) at +20° C, -20° C, +50° C, +20° C. + +Test description The samples shall be placed in a climatic chamber as a loose coil and cycled as reported in test conditions. The free cable ends shall be placed out of the climatic chamber and the fibres connected to the measurement apparatus. + +NOTE – Test monitoring at the end of each temperature step should be performed when the sample has reached a stable temperature. + +Test monitoring OTDR measurements shall be carried out before and after the test and at the end of each temperature step. + +Requirements + +- At the end of each temperature step, the change in attenuation shall be less than 0.1 dB/splice; +- After the tests, there is no significant change in attenuation of splices. + +### 9.2 Tensile with twist restrained + +#### Objectives + +- To prove that the closure can withstand the maximum expected tensile load that can be applied on a cable during the laying, service and recovery, with a known degree of safety; +- To prove that the closure can withstand mechanical twisting applied either during load or after unload; +- To determine whether the performance of the closure under load would permit its reuse after intervention and/or recovery operation. + +International standard 7.2.2.1/G.976; IEC 60794-1-2 Method E1. + +Sample preparation As described in 9.1. Moreover, each end of the sample is terminated with an anchoring device. The anchoring devices shall be such as to permit access to both ends of the cable specimens for optical testing. + +Test conditions + +- Temperature: ambient; +- Load: = NTTS. + +NOTE – For closure connected to armoured cables, the load shall be = 80% of the strength of the outer armour layer of cable; + +- Time: 1 cycle of 1 hour at NTTS plus 1 of short time. + +| | | +|------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Test description | One anchoring device of the sample is fixed to a rotating cable clamp, the other anchoring device is fixed to a fixed cable clamp. The rotating cable clamp is connected to a suitable turning equipment (e.g., a torquing lever, for detecting the applied torques). Both ends of the sample are not twisted during the tensile test. The sample is pulled, increasing the load up to NTTS and maintained for 1 hour; then the load is decreased to a minimum value and again is pulled up to NTTS, maintained for short time and then completely released. | +| Test monitoring | The optical attenuation of fibres and splices shall be continuously monitored throughout the test. Cable elongation, tensile load and torque of the cable ends are continuously measured during the test. | +| Requirements |
  • – During the test: the change in attenuation shall be less than 0.1 dB/splice.
  • – After the test, there should be no significant change in attenuation; nor closure break.
| + +### 9.3 Tensile with torque minimized + +#### Objectives + +- To prove that the closure (and cable terminations) can withstand the maximum expected tensile load that can be applied on a cable during laying, service and recovery, with a known degree of safety; +- To prove that the optical fibres inside the cable specimens and inside the closure, are not subjected to excessive strain either during loading or after unloading. + +| | | +|------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| International standard | 7.2.2.2/G.976; IEC 60794-1-2 Method E7. | +| Sample preparation | As described in 9.2. | +| Test conditions |
  • – Temperature: ambient;
  • – Load: = NOTS;
  • – Time: 1 cycle of 1 hour plus 1 short.
| +| Test description | The testing method of sample n.1 is repeated but the torque is minimized. The sample is pulled twice increasing the load up to NOTS, maintained for 1 hour and then completely released. For the short cycle test, see the previous test description. | +| Test monitoring | The optical attenuation of fibres and splices shall be continuously monitored throughout the test. The elongation of the cable shall be continuously measured during the test. | +| Requirements |
  • – During the test: the change in attenuation shall be less than 0.1 dB/splice;
  • – After the test, there should be no significant change in attenuation; nor closure break.
| + +### 9.4 Bending under tension (sheave passage) + +#### Objective + +To prove that the closure can withstand the bending forces applied during its installation or recovery without degradation. + +International standard 7.2.2.5/G.976; IEC 60794-1-2, Method E18. + +Test conditions + +- Temperature: ambient; +- Load: = NOTS and NTTS; +- Time: 10 cycles at NOTS plus 3 at NTTS; + +Test description + +One end of the sample is fixed to a hydraulic cylinder, the other end is fixed to a clamp. Then, under a constant load equal to NOTS, the sample is passed around a 3 m diameter sheave, with a speed of about 0.3 knots (approximately 9.24 m/minute), in a clockwise and anti-clockwise direction 10 times and again three times with a load equal to NTTS. The terminations are not allowed to rotate. If different cable types are used at each end of the closure, the lower NOTS value shall be selected. + +Test monitoring + +- Continuously monitoring the attenuation of the optical link; +- Splice attenuation measurements shall be carried out before the test (as reference) and about 20 minutes after the test. + +Requirements + +- During the test: the change in attenuation shall be less than 0.1 dB/splice. +- After the test, there should be no significant change in attenuation; nor closure break. + +### 9.5 Repeated bending (optional) + +#### Objective + +To prove that the closure can withstand repeated bending (bend fatigue) that can be applied near the cable terminations during the handling (from factory-to-ship, tank-to-tank, etc.), without degradation. + +International standard 7.2.3.3/G.976; IEC 60794-1-2 (E6). + +Test conditions + +- Temperature: ambient; +- Duration: 100 cycles of approximately 5 seconds duration. + +Test description + +The upper cable shall be fastened to a pivot arm; the lower cable is loaded with a weight sufficient to keep the cable straight. With the pivot arm vertical, the cable termination to the closure shall be at the centre height of the sheave of typically 1 m diameter. The sample is alternately bent, for example by means of an airdriven pendulum, between two test fixtures representing at least a quadrant of such a sheave. + +Test monitoring + +OTDR measurements shall be carried out before (reference measurements), during and after the test. + +| | | +|--------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Requirements |
  • – During the test: the change in attenuation shall be less than 0.1 dB/splice.
  • – After the test, there should be no significant change in attenuation; nor closure break.
| +|--------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| + +### 9.6 Hydraulic pressure resistance + +#### Objectives + +- To prove that the closure is waterproof and can withstand the maximum water pressure; +- To prove that the electrical insulation resistance is maintained. + +International standard 7.2.1.4/G.976; IEC 60794-1-2 Method F10 (under consideration). + +Sample preparation All ports of splice closure shall be terminated with cable samples; the other ends of such cables shall appropriately be sealed. For practical reasons, the cable armour wires are removed from the sample. + +Test conditions + +- Time: more than 24 h; +- Pressure: The pressure on the sample (pressure inside the chamber containing water) is increased to a level simulating the maximum water depth for the installation. + +Test description The sample shall be externally pressurized with water. The pressure shall be gradually raised to the maximum foreseen value and kept stable before the pressure is relieved. The rate of pressure builds up and relief should be approximately 15 bar/minute typically (simulating the normal laying speed). + +Test monitoring Splice attenuation and insulation resistance (optional) should be monitored during the test period; + +Requirements + +- During the test: the change in attenuation shall be less than 0.1 dB/splice; the electrical insulation resistance shall be more than 20 M $\Omega$ (optional). +- After the test, there should be no change in attenuation; nor evidence of creep or deformation of closure; nor water ingress in the sample; nor closure collapse. + +### 9.7 Bumps + +#### Objective + +To prove that the joint closure can withstand mechanical shocks (bumps or impacts) that may occur during laying and/or recovery operations, without sustaining either physical damage or residual attenuation increases. + +International standard Not Available + +Sample preparation See 9.6. + +Test conditions + +- Temperature: ambient; +- Acceleration of 20 g; + +NOTE 1 – A lower value can be chosen among agreement between the Customer and Manufacturer. + +- Number of Bumps: 100 along each principal axis. + +| | | +|------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Test description | The sample is inserted in a machine bumping the closure at the required acceleration. The closure is stressed 100 times along each of the principal axes with an acceleration of 20 g (see Note 1) and for a time of 6 ms (each bump). | +| Test monitoring | Optical attenuation of fibre splices is continuously monitored during the test.
NOTE 2 – Due to possible oscillations transferred from the sample to the patch cords linking the test apparatus, it is possible that high optical attenuation can be detected during the test. | +| Requirement | After the test: no significant change in attenuation shall be detected; no physical damage (cracks or fissures) should be observed on the closure. | + +### 9.8 Vibration + +#### Objective + +To demonstrate that the closure is able to withstand vibrations caused during loading, transport and laying (recovery) operations. + +| | | +|------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| International standard | IEC 61300-2-1; IEC 60068-2-6 | +| Sample preparation | See 9.6. Both the free ends of cables shall be sealed. | +| Test conditions |
  • – Sweep range: from 10 to 100 Hz; sweep rate 0.5 octave/min;
  • – Acceleration: 5 g;
  • – Number of cycles: 5 sweeps per each axis;
  • – Direction: 3 mutually perpendicular axes.
| +| Test description | The sample for each one of its axes is vibrated for 8 hours at frequencies varying between 10 and 100 Hz, with an acceleration of 5 g.
NOTE – A lower value of test duration can be agreed between the Customer and Manufacturer. | +| Test monitoring | Optical attenuation of fibre splices are continuously monitored. | +| Requirements |
  • – During the test: the change in attenuation shall be less than 0.1 dB/splice.
  • – After the test, no significant change in attenuation nor any physical degradation should be observed.
| + +### 9.9 Corrosion resistance (optional) + +#### Objectives + +- To prove that the closure can withstand long-term exposure to sea water; +- To prove that any corrosion present will not impair the mechanical, optical and electrical function of the closure. + +| | | +|------------------------|-----------------------------------------------------------------------------------------------------------| +| International standard | 7.2.4.2/G.976; IEC 61300-2-26. | +| Sample preparation | The closure is terminated to both ends with about 10 m of underwater cables having the other ends sealed. | + +| | | +|------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Test conditions |
  • – Sea water or artificial sea water (i.e., salt content of 5% NaCl in water);
  • – Pressure: 0 kPa;
  • – Temperature: 50° C (typically);
  • – Time: 5 days.
| +| Test description | The submersible plant (closure and cable) is immersed in water having characteristics similar to those that the closure will be operating under (as reported in test conditions). The plant is then inspected to determine the degree of corrosion and, if applicable, the build-up of hydrogen gas. A provision must be made for suitably sealing the cable ends prior to the test. If artificial sea water is used, its specification is to be stated. | +| Requirement | After the test: no evidence of variation in mechanical, optical and electrical function should be observed. | + +## **Appendix I** + +### **Examples of different closure designs available on the market** + +This appendix can be filled and updated in the future by adding information coming from closure designs available on the market. + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure, Internet protocol aspects and Next Generation Networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.55-200311-I_PDF-E/16152cf1d84aea10848758f51a91ff6a_img.jpg b/marked/L/T-REC-L.55-200311-I_PDF-E/16152cf1d84aea10848758f51a91ff6a_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..6fa2ae7e2e84470260dfee8cf909c5c143693a17 --- /dev/null +++ b/marked/L/T-REC-L.55-200311-I_PDF-E/16152cf1d84aea10848758f51a91ff6a_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:8f91ecafcc567873f70198429a6f7238b8b5bc11714de669b26311fba8e91c82 +size 212793 diff --git a/marked/L/T-REC-L.55-200311-I_PDF-E/1d529a819ad929684331c55eed6673bb_img.jpg 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+version https://git-lfs.github.com/spec/v1 +oid sha256:5faef0594d7bdd41bd2b28f3f58433ea32c019dcce9b8c65971becd857e6766a +size 25585 diff --git a/marked/L/T-REC-L.55-200311-I_PDF-E/raw.md b/marked/L/T-REC-L.55-200311-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..dc94504d942d9f325b23548608ef023d0fd0c3ba --- /dev/null +++ b/marked/L/T-REC-L.55-200311-I_PDF-E/raw.md @@ -0,0 +1,545 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a lightning bolt superimposed on it, and the letters 'ITU' written across the center. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.55** + +(11/2003) + +SERIES L: CONSTRUCTION, INSTALLATION AND +PROTECTION OF CABLES AND OTHER ELEMENTS OF +OUTSIDE PLANT + +--- + +**Digital database for marine cables and pipelines** + +ITU-T Recommendation L.55 + +--- + + + +# **ITU-T Recommendation L.55** + +# **Digital database for marine cables and pipelines** + +## **Summary** + +This Recommendation describes the nature of the information regarding marine cables and pipelines that should be maintained by National or Regional government agencies which are responsible for marine shorelines, and the cable or pipeline installations that may either be present or added. + +Information about marine cable and pipeline installations can affect the cost of future installations or maintenance, including their environmental impact. At present, there is no global authority to maintain such information and the responsibility rests with individual countries. Given that information from multiple shoreline databases is necessary in designing new cable links, a standardization of the information that should be maintained will assist all participating parties. Such information is also useful in managing shoreline infrastructure when cables and pipelines are decommissioned, thereby allowing the possibility of reusing the space. + +## **Source** + +ITU-T Recommendation L.55 was approved on 28 November 2003 by ITU-T Study Group 6 (2001-2004) under the WTSA Resolution 1. + +## **Keywords** + +Database, marinized terrestrial cable, submarine cable, survey. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2004 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +| | | Page | +|-----|-----------------------------------------------------------------------------------------------------------------|------| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Terms and Definitions ..... | 1 | +| 4 | Abbreviations..... | 2 | +| 5 | Overview ..... | 2 | +| 5.1 | Regulating body..... | 2 | +| 5.2 | Owner/Operators ..... | 2 | +| 5.3 | Installers ..... | 3 | +| 5.4 | Other commercial entities..... | 3 | +| 6 | Database contents ..... | 3 | +| 6.1 | Primary record ..... | 3 | +| 6.2 | Activity record..... | 6 | +| 7 | Database initiation ..... | 6 | +| 7.1 | Charts..... | 6 | +| 7.2 | Reports and logs ..... | 6 | +| 7.3 | Software..... | 6 | +| 7.4 | Security..... | 6 | +| 7.5 | Infrastructure owners..... | 7 | +| 7.6 | Initial data..... | 7 | +| 7.7 | Field survey ..... | 7 | +| 8 | Maintenance..... | 7 | +| 8.1 | Charts and reports..... | 7 | +| 8.2 | Contact point ..... | 7 | +| | Appendix I – More information and justification on the need for marine infrastructure
digital databases..... | 8 | +| | BIBLIOGRAPHY ..... | 15 | + + + +# Digital database for marine cables and pipelines + +# 1 Scope + +This Recommendation covers the reasons for maintaining a digital database for marine cables and pipelines. It outlines the minimum contents of such a database and recommends procedures by which such databases can be initiated, maintained, and used. + +This Recommendation assumes that the creation and maintenance of these digital databases are under the responsibility of National or Regional government agencies that are responsible for the shorelines where marine cables or pipelines are terminated. This Recommendation does not mandate National or Regional regulations on data collection and dissemination, but does offer the possibility of determining a minimum set of data needed. + +This Recommendation is applicable for the creation of digital databases to be implemented after it enters into force. + +This Recommendation is originated and maintained by ITU-T Study Group 6, "Outside plant", which normally has within its scope construction, installation, and maintenance of marinized terrestrial communication cables. The recommended database applies, however to the following, which are normally not in the scope of SG 6: + +- Submarine telecommunication cables (ITU-T Rec. G.972); +- Submarine electrical power cables; +- Submarine pipelines. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- ITU-T Recommendation L.28 (2002), *External additional protection for marinized terrestrial cables*. +- ITU-T Recommendation L.29 (2002), *As-laid report and maintenance/repair log for marinized terrestrial cable installation*. + +# 3 Terms and Definitions + +This Recommendation defines the following terms: + +**3.1 regulating body (RB):** The National or Regional government agency that is responsible for maintaining records of a given portion of shoreline and the associated waters. + +**3.2 shoreline region:** The shores and associated waters under the authority of a given regulating body. + +**3.3 cable awareness charts (CAC):** Detailed maps of the shorelines including the waters in the vicinity. These maps may or may not be digital, but should be numbered in a manner consistent with accessing them, based on a pointer. + +**3.4 transport infrastructure:** The cable or pipeline that is deployed undersea with a shore termination. + +**3.5 terminating infrastructure:** Buildings and protections at the interface of land and sea that are not part of the transport infrastructure, but which are part of the overall installation. + +**3.6 owner/operator:** The entity that holds the legal ownership of the transport and terminating infrastructure and the associated rights of way or real property. + +**3.7 installer:** The entity that completes the actual installation. + +**3.8 local termination:** The point within the shoreline region where a transport infrastructure terminates. + +**3.9 distant termination:** The point outside the shoreline region where the transport infrastructure terminates. + +NOTE – When a given transport infrastructure is terminated at both ends in the same shoreline region, there should appear two records in the database of the RB, one for each. For each, the distant termination will be a reference to the other end. + +# **4 Abbreviations** + +This Recommendation uses the following abbreviations: + +CAC Cable Awareness Chart + +ITU International Telecommunication Union + +RB Regulating Body + +# **5 Overview** + +Information on the benefits of maintaining databases is given in Appendix I. It is assumed that one database is maintained by the RB of a given shoreline region. In many cases, the databases of multiple RBs may need to be researched before a complete new link design can be completed. While the position and condition of transport infrastructure that passes under the open sea may be available, this information is included only as an optional map pointer. + +The database for a given shoreline region can only be initiated and maintained with the cooperation of several parties, each with different responsibilities. The following outlines the roles of these parties: + +NOTE – This Recommendation is applicable for the creation of digital databases to be implemented after it enters into force. + +## **5.1 Regulating body** + +- Initiate the database (see clause 7). +- Communicate the requirements to owner/operators and installers. +- Maintain the CACs. +- Add new data to the database. +- Establish database security policies and access requirements. +- Publish guidelines on sea surface transportation (shipping, etc.) and water use (fisheries) to prevent damage to transport infrastructure. + +## **5.2 Owner/Operators** + +- Review the database before planning a new installation to avoid damaging existing infrastructure. + +- Include the requirements of the RB in contracts with the installers. +- Require installers to conform to the requirements of ITU-T Rec. L.29. +- Conform to the requirements of ITU-T Rec. L.29 for maintenance. +- Inform the RB when the transport infrastructure is no longer in use. + +## 5.3 Installers + +- Check the database before proceeding with new installations. +- Conform to the requirements of the RB and ITU-T Rec. L.29. + +## 5.4 Other commercial entities + +These include: + +- Fishing authorities; +- Vessel owners and captains; +- Military authorities; +- Offshore oil operators; +- Port authorities; +- Hydrographic offices. + +All these entities are responsible for reviewing and publicly following available guidelines from the RB. Those entities that may have database access are responsible for reviewing the database before engaging in any new programs that may cause infrastructure damage, or before changing existing infrastructure. + +# 6 Database contents + +The overall database consists of four primary elements, the first two of which can be digital. The others, which may exist only in paper copy, should be organised with identification numbers which can be referenced. These are: + +- Primary records; +- Activity records; +- Cable awareness charts; +- Installation and maintenance logs and reports. + +The primary records are for the retention of information that does not change much with time. They include a primary ID defined with the longitude and latitude of the termination point, along with a serial number for possible multiple items at a given location. They also contain information on the owner, installer, distant termination, charts, and other descriptors. They also contain pointers to the first and last activity records, which form a linked list. + +Every activity, including that of primary record initiation is reflected by an activity record. These records indicate time dependent material such as record initiation, and pointers to various reports that may occur during installation, maintenance or decommissioning. The dates and identification of the person authorizing the data entry are among the items included in these records. + +NOTE – This Recommendation is applicable for the creation of digital databases to be implemented after it enters into force. + +## 6.1 Primary record + +Table 1 contains the recommended fields for the primary records. + +**Table 1/L.55 – Primary record fields** + +| Description | Field | Data type | Notes | +|--------------------|--------------|------------------|-----------------------------------------------------------------------------------------------------------------------| +| Primary ID | Longitude | number | This is the unique identification for each item of infrastructure | +| | Latitude | number | It is positional to allow the addition of future installations between current ones | +| | Serial | number | The serial number is used to distinguish between items that are so close (they have the same location) | +| Cable type | Primary | code | 0 power line, 1 oil pipe, 2 gas pipe, 3 electrical telecom, 4 optical telecom with electricity, 5 all optical telecom | +| | Secondary | code | This secondary code is for local use to further differentiate types of infrastructure | +| Permits | Right of Way | text | These fields are provided to allow a pointer to local legal permits | +| | Property ID | | | +| | Construction | text | | +| Owner | Name | text | If the owner is not known, enter Unknown | +| | Address | text | | +| | Telephone | number | | +| | Fax | number | | +| | email | text | | +| Status | InUse | binary | This is to record whether the infrastructure is out of use | +| | Replaced | binary | This is to record whether the infrastructure has been replaced with new | +| Replacement ID | longitude | number | This is a pointer to the replacement infrastructure | +| | latitude | number | | +| | Serial | number | | +| Installer | Name | text | If the installer is not know, enter Unknown | +| | Address | text | | +| | Telephone | number | | +| | Fax | number | | +| | email | text | | + +**Table 1/L.55 – Primary record fields** + +| Description | Field | Data type | Notes | +|-------------------------|-------------------------------------------------------------|------------------|-----------------------------------------------------------------------------------------| +| Termination description | Legal address | text | Used to find the termination from the terrestrial side | +| | Description of the shoreline | text | | +| | Building present | binary | | +| | Description of additional protections (see ITU-T Rec. L.28) | text | | +| | Other | text | This can be used to document items such as close presence of other infrastructures | +| Cable Awareness Charts | Number referenced | number | More than one chart might be referenced | +| | Chart1 | text | | +| | Chart2 | text | | +| | Chart3 | text | | +| | Chart4 | text | | +| | Chart5 | text | | +| | Chart6 | text | | +| | Chart7 | text | | +| Distant Termination | Distant RB name | text | If the distant RB is not known, enter Unknown | +| | Name | text | | +| | Address | text | | +| | Telephone | number | | +| | Fax | number | | +| | email | text | | +| Distant RB primary ID | Longitude | number | These can be used to identify the details associated with the distant termination point | +| | Latitude | number | | +| | Serial | number | | +| Activity Record | First record ID | number | This points to the first activity record | +| | Last record ID | number | This points to the last activity record | + +## 6.2 Activity record + +Table 2 contains the recommended fields for the activity records. + +**Table 2/L.55 – Activity record fields** + +| Description | Field | Data type | Notes | +|-------------------|---------------------|-----------|---------------------------------------------------------------------------------------------| +| Source primary ID | longitude | number | All activity records need pointer to "owner" | +| | latitude | number | | +| | serial | number | | +| Activity pointers | Prior | number | Negative if first | +| | Next | number | Negative if last | +| Data entry data | Date | date | | +| | Employee | text | This could be a number for some RBs | +| Activity data | date | date | | +| | Source organization | code | 0 RB, 1 owner, 2 installer | +| | Activity type | code | 0 initiation, 1 correction/update,
2 maintenance, 3 out of use,
4 replacement/removal | +| | Activity summary | text | This should be a brief description | +| | Document ID | | This should point to a complete document as
the As-laid log or a survey report | + +# 7 Database initiation + +Define and document the shores and waters covered by the database. Inform any related government agencies of the intent to create the database and request their assistance in enforcing reporting requirements. + +## 7.1 Charts + +Define and document the means by which the charts are organized and labelled. Gather the existing charts into this organization. + +## 7.2 Reports and logs + +Define and document the means by which the reports and logs are organized and labelled. Gather the existing reports into this organization. + +## 7.3 Software + +Create or obtain software that is suitable for efficient data-entry and extraction and that is compatible with the record field structure and the means of identifying charts and reports. + +## 7.4 Security + +Define and document the database security policy and data access requirements. + +## **7.5 Infrastructure owners** + +Prepare a list of known infrastructure owners and, if possible, sublists of the individual infrastructures owned by each. Prepare a survey form that contains fields appropriate for the owners to enter the data needed for the records. Gather any existing data and pre-fill out the surveys to the best level. + +Prepare a notification of the intent to create a database, along with reference to any laws of authorization and send it, along with the survey, to the known owners. Include in the notification the security policies. + +## **7.6 Initial data** + +Update the database with initial data and the survey results. In many cases, the data may be incomplete. Empty fields or some missing value code can be used to note this. The decision to follow-up on missing data is for the RB. + +## **7.7 Field survey** + +Field surveys, taking one sub-shore region at a time, are also a recommended means of gathering initial data. Using satellite location devices can greatly facilitate obtaining the position of observed infrastructure termination. The survey team should also be trained in the use of ITU-T Recs L.28 and L.29, as well as this Recommendation, to facilitate their work. + +# **8 Maintenance** + +The proper initialization of the database should greatly facilitate its maintenance. + +## **8.1 Charts and reports** + +Prepare to add or modify charts and reports. The revision of charts, in particular, should be done with care. Often, rather than modifying an existing chart, a new chart identification number should be created. The prior chart should also be marked with a "forward pointer" to the chart that replaces it and the revised chart should be marked with a "backward pointer" to the chart it replaces. This will reduce the need to update the database. + +In general, reports should not be modified. Provision exists with the activity records to add new reports. At some point it may be desirable to microfilm or electronically store the reports. The design of the organization of the reports should take this into account. + +## **8.2 Contact point** + +A single department should be identified as the "Owner" of the database. This department should control all new entries and serve as the principle contact. The internal procedures of this department should be documented. + +# Appendix I + +## More information and justification on the need for marine infrastructure digital databases + +In the last decade, a huge number of new underwater cables have been laid all over the world which have caused, in many cases, an overcrowding of many shore approach areas. + +The liberalization of markets in general (telecom, energy, gas pipeline, oil pipeline, etc.) has caused, in the above-mentioned shore areas, an increased presence of underwater cables and other services from different companies. + +It is necessary to take into consideration the time and the cost associated with the necessary detailed route survey that each telecommunication and other companies have generally to perform when new cable has to be laid in shallow water areas, or when a maintenance activity has to be carried out on existing plants in the same areas. + +The application of this Recommendation should consider the importance, in terms of total transmission capacity, of the new underwater cables and the necessity to reduce the time it takes to obtain permission from local authorities and to carry out the route survey, both for laying new cables and for repairs. + +The existence of many old plants (i.e. decommissioned plants) whose position is not well defined suggests the necessity of carrying out a survey and mapping these areas with greater accuracy by using new survey technologies, such as Differential GPS (Global Positioning System) for positioning "cable trackers" and "pipe trackers" for submarine services detection. Certain equipment can be installed on a Remotely Operated Vehicle (R.O.V.) system, where water depth, conditions and extent of the area involved allows it. + +Such a survey would allow us to know which submerged services exist, as well as being a tool to avoid overlaying and plant damages during cable burial or maintenance activities. + +In order to simplify the operation related to the installation of new infrastructures (cables, gas pipeline, oil pipeline, etc.) as well as to minimize the environmental impact, it is advisable to recover cables out of service, obsolete or dismissed. + +In such cases, the owners of new cable(s), in agreement with the owners of the dismissed cable(s), shall arrange for the recovery of as many such cables as possible in order to minimize future interference with other users. + +Even though there are some national authorities (i.e. the most important Hydrographic Institutes) which have created a kind of cable database (at least to update the nautical charts of the country concerned), the information available often does not reflect the real situation. + +Moreover, there are several countries which have no record offices and, in any case, references, sources and geodesy of the data, when available, often differ from one country to another. + +Recent experiences of cable owners and installers confirm the above statements, i.e. they have found that it is impossible to get reliable information in areas of high concentration of plants originating from different countries and from several unknown owners (e.g. recently, in the Gibraltar Strait it was ascertained that neither the local nor Governmental authority, nor the Hydrographic Institutes of Spain and Morocco, nor the British Admiralty nor telecom/power companies were capable of providing the installer company with suitable and useful data (see the maps attached to Appendix I showing the problem of existing cables crossing the strait). + +Therefore, in order to assist cable owners whose planned systems will cross or closely approach existing in-service cables, and owners of existing systems which may be crossed by a planned + +system, it is advisable that a "Digital Database" containing updated, reliable and, whenever possible, uniform information be created for future reference. + +Moreover, the availability of such a database, concerned with the sensitive issue of underwater installations, would greatly facilitate the work of the interested parties, such as cable owners, installer companies, any plant maintenance authority, etc., involved in laying/maintenance/recovering of underwater cables or other underwater plant installations. The creation of a digital database could be particularly useful for those areas in which a lot of cables or services already exist (i.e. overcrowded shore approach areas). + +Besides, the availability of an updated digital database on the above matter could have a double effect: + +- a) to avoid or to minimize any possible damage to existing services that could occur during laying and burial operations; +- b) to save time and money each time interventions have to be made for repairs/recovering or for surveying. + +Below is a list of possible involved entities and/or recommended actions, information, and documentation that could be useful to the different organizations involved: + +### **a) Information for the fishing authorities and for owners/captains:** + +Updated copies of cable warning charts, which show very clearly the position of underwater cables and the boundaries of cable protection areas, as well as information on how to contact the cable maintenance authorities for any clarification or additional information. + +Such documentation can be provided by the local Hydrographic or Oceanographic Institutes or by commercial organizations. It may also be useful to provide such authorities with video material, showing the seabed and highlighting the most important problems which occurred during the laying/recovering, etc. + +### **b) Information to other marine authorities such as:** + +***Military authorities*** in order to: + +- ensure that their vessels do not damage cables when anchoring; +- ensure that potentially dangerous submarine activities, such as submarine explosions/firing, etc. are avoided in submarine cable areas; +- ensure that new telecommunication cable systems, maintenance or recovery operations carried out on the existing ones, do not impact on existing military facilities or ongoing military activities. + +***Commercial entities***, such as: + +- Offshore operators; +- Oil companies, etc. + +***Port authorities*** + +- which are responsible for maritime traffic corridors and ship mooring or waiting areas. + +***Cable maintenance authorities*** in order to: + +- ensure regular exchange of information among cable maintenance authorities within each area. + +***Hydrographic offices*** in order to: + +- be informed of a new cable installation and the status of existing cables for updating nautical charts. + +c) **Information to terrestrial authorities**, such as: + +***Local authorities and environmental authorities*** in order to: + +- be informed on the routes of land cables and on the location of beach joint facilities to protect cables and infrastructure from potential damage caused by future works. + +In order to illustrate the information procedure and the content of such a digital database, in relationship with existing ITU-T reference documents, refer to Figure I.1. + +![Flowchart of the marine infrastructure proposal database process, showing inputs from ITU-T reference documents and the creation of a national or regional cables database.](16152cf1d84aea10848758f51a91ff6a_img.jpg) + +The flowchart illustrates the information procedure for a marine infrastructure proposal database. It starts with **ITU-T Reference documents** pointing to the **Handbook on MTC- Chpt. III, Survey and route planning**. This handbook feeds into a shaded box containing **Desk study**, **Magnetometer search**, and **Survey report**. Below this box, the flow continues through **ITU-T Rec. L.28 External additional protection for marinized terrestrial cables** and **ITU-T Rec. L.29 As-laid report and maintenance / repair log for marinized terrestrial cable installation**. This is followed by another shaded box with **Installation/Protections** and **Landing point-map**. The main process on the right side begins with a box for **National or regional cables database** (To be created according to ITU-T Rec. L.55). An **Output** arrow points from this box to a sequence of three dashed boxes: **1. Data acquisition of existing information**, **2. Detailed marine survey with modern technologies**, and **3. Mapping of the detected submersible plants according to digital techniques**. These three steps lead to **Update the cables database**. An **Input** arrow points from this update box back to the **National or regional cables database** box. Dashed lines connect the shaded boxes on the left to the dashed boxes on the right: **Desk study** to **1. Data acquisition of existing information**, **Magnetometer search** to **2. Detailed marine survey with modern technologies**, and **Survey report** to **3. Mapping of the detected submersible plants according to digital techniques**. Additionally, a dashed line connects the **Landing point-map** box to the **Update the cables database** box. + +Flowchart of the marine infrastructure proposal database process, showing inputs from ITU-T reference documents and the creation of a national or regional cables database. + +L.055\_Fl.1 + +**Figure I.1/L.55 – Marine infrastructure Proposal database** + +![Map of the Strait of Gibraltar showing existing and planned submarine cable routes. The map includes a north arrow, a vertical green label 'All other existing cables crossing the Strait of Gibraltar', and various colored lines representing different cable systems. Annotations include '1st Interconnection Spain-Morocco' with pink arrows and 'Future 2nd Interconnection Spain-Morocco' with a black arrow pointing to a blue line.](1d529a819ad929684331c55eed6673bb_img.jpg) + +STRAIT OF GIBRALTAR + +All other existing cables crossing the Strait of Gibraltar + +SELECTED CABLES INTERCONNECTION + +1st INTERCONNECTION SPAIN - MOROCCO + +Map of the Strait of Gibraltar showing existing and planned submarine cable routes. The map includes a north arrow, a vertical green label 'All other existing cables crossing the Strait of Gibraltar', and various colored lines representing different cable systems. Annotations include '1st Interconnection Spain-Morocco' with pink arrows and 'Future 2nd Interconnection Spain-Morocco' with a black arrow pointing to a blue line. + +**1st Interconnection Spain-Morocco** + +**Future 2nd Interconnection Spain-Morocco** + +![Legend for the map, detailing the color coding for different cable digitizing sources and symbols for various cable components and routes.](fed39b841ae2dce01088b84bfc1e2789_img.jpg) + +**LEGEND** + +- Cable digitizing from Admiralty comm. Pag.01 +- Cable digitizing from Admiralty comm. Pag.02 +- Cable digitizing from Admiralty comm. Pag.04 +- Cable digitizing from Admiralty comm. Pag.05 +- Cable digitizing from Admiralty comm. Pag.06 +- Cable digitizing from Admiralty chart N°142 +- 1st Interconnection Spain-Morocco +- Glomar Post with K.P.O in Spain +- Final Selected Survey Route +- Glomar Post with K.P.O in Morocco +- Final Selected Cables Route 2nd Intercon. +- Pre-selected cables routes (see report IMRESUB 11-2001) +- Turning Point on Final Selected Cable Route + +Legend for the map, detailing the color coding for different cable digitizing sources and symbols for various cable components and routes. + +L.055\_fl.2a + +![A detailed nautical chart of the Gibraltar Strait area, showing the coastline of Spain and Gibraltar, the Rock of Gibraltar, and various navigational features. The chart includes depth soundings, contour lines, and numerous handwritten annotations in red ink. Notable annotations include 'BP 70/124(L) Sheet 13', 'BP 65/38', 'BP 10/44', and 'BP 65/37'. Other geographical labels include 'Cabezon Passage', 'Bajada de Fuera', 'Los Cabezos', 'Rio de San Pedro', 'TARIFA', 'ISLA DE SAN SEBASTIAN', 'Puntales', 'Puntales (3)', 'Puntales (4)', 'Puntales (5)', 'Puntales (6)', 'Puntales (7)', 'Puntales (8)', 'Puntales (9)', 'Puntales (10)', 'Puntales (11)', 'Puntales (12)', 'Puntales (13)', 'Puntales (14)', 'Puntales (15)', 'Puntales (16)', 'Puntales (17)', 'Puntales (18)', 'Puntales (19)', 'Puntales (20)', 'Puntales (21)', 'Puntales (22)', 'Puntales (23)', 'Puntales (24)', 'Puntales (25)', 'Puntales (26)', 'Puntales (27)', 'Puntales (28)', 'Puntales (29)', 'Puntales (30)', 'Puntales (31)', 'Puntales (32)', 'Puntales (33)', 'Puntales (34)', 'Puntales (35)', 'Puntales (36)', 'Puntales (37)', 'Puntales (38)', 'Puntales (39)', 'Puntales (40)', 'Puntales (41)', 'Puntales (42)', 'Puntales (43)', 'Puntales (44)', 'Puntales (45)', 'Puntales (46)', 'Puntales (47)', 'Puntales (48)', 'Puntales (49)', 'Puntales (50)'.](b53846f262c6904a1b45abef2e95fbd8_img.jpg) + +A detailed nautical chart of the Gibraltar Strait area, showing the coastline of Spain and Gibraltar, the Rock of Gibraltar, and various navigational features. The chart includes depth soundings, contour lines, and numerous handwritten annotations in red ink. Notable annotations include 'BP 70/124(L) Sheet 13', 'BP 65/38', 'BP 10/44', and 'BP 65/37'. Other geographical labels include 'Cabezon Passage', 'Bajada de Fuera', 'Los Cabezos', 'Rio de San Pedro', 'TARIFA', 'ISLA DE SAN SEBASTIAN', 'Puntales', 'Puntales (3)', 'Puntales (4)', 'Puntales (5)', 'Puntales (6)', 'Puntales (7)', 'Puntales (8)', 'Puntales (9)', 'Puntales (10)', 'Puntales (11)', 'Puntales (12)', 'Puntales (13)', 'Puntales (14)', 'Puntales (15)', 'Puntales (16)', 'Puntales (17)', 'Puntales (18)', 'Puntales (19)', 'Puntales (20)', 'Puntales (21)', 'Puntales (22)', 'Puntales (23)', 'Puntales (24)', 'Puntales (25)', 'Puntales (26)', 'Puntales (27)', 'Puntales (28)', 'Puntales (29)', 'Puntales (30)', 'Puntales (31)', 'Puntales (32)', 'Puntales (33)', 'Puntales (34)', 'Puntales (35)', 'Puntales (36)', 'Puntales (37)', 'Puntales (38)', 'Puntales (39)', 'Puntales (40)', 'Puntales (41)', 'Puntales (42)', 'Puntales (43)', 'Puntales (44)', 'Puntales (45)', 'Puntales (46)', 'Puntales (47)', 'Puntales (48)', 'Puntales (49)', 'Puntales (50)'. + +GIBRALTAR STRAIT – OLD SITUATION (Map 2) + +L.055\_fl.2b + +![A detailed topographic map of the Gibraltar Strait area, showing Isla de Tarifa, various roads, and geographical features. The map is heavily annotated with red and blue lines and text. Notable labels include 'Cabezas Passage', 'Isla de Tarifa', 'Abandoned (ex Casablanca 1945)', and 'Abandoned (ex Scrat 1959)'. There are numerous elevation points and smaller geographical names like 'Rajeta de Fuera' and 'Paso Nuevo'.](b2d16e07bfa79d67a8adabf7e26c7764_img.jpg) + +A detailed topographic map of the Gibraltar Strait area, showing Isla de Tarifa, various roads, and geographical features. The map is heavily annotated with red and blue lines and text. Notable labels include 'Cabezas Passage', 'Isla de Tarifa', 'Abandoned (ex Casablanca 1945)', and 'Abandoned (ex Scrat 1959)'. There are numerous elevation points and smaller geographical names like 'Rajeta de Fuera' and 'Paso Nuevo'. + +GIBRALTAR STRAIT – OLD SITUATION (Map 3) + +L.055\_fl.2c + +![A detailed nautical chart of the Gibraltar Strait. The map shows the coastline of Spain to the north and Morocco to the south. Key features include Puntales, Puntales de la Punta, Los Cabezos, and the city of Gibraltar with its 'WATER TOWER' and 'See Plan' callout. The strait is divided into traffic zones with arrows indicating the direction of flow. Depth soundings are scattered throughout the water areas. The label 'STRAIT OF GIBRALTAR' is prominently displayed in the center. Other labels include 'Inshore Traffic Zone', 'Eastgoing 1-hour', 'Westgoing 1 1/2 hours', and 'Eastgoing 4 hours'. The bottom of the map shows the coastline of Morocco with labels like 'Ras el Ma' and 'Ras el Hajar'.](3102c32204f998dba666e1e915d5babf_img.jpg) + +A detailed nautical chart of the Gibraltar Strait. The map shows the coastline of Spain to the north and Morocco to the south. Key features include Puntales, Puntales de la Punta, Los Cabezos, and the city of Gibraltar with its 'WATER TOWER' and 'See Plan' callout. The strait is divided into traffic zones with arrows indicating the direction of flow. Depth soundings are scattered throughout the water areas. The label 'STRAIT OF GIBRALTAR' is prominently displayed in the center. Other labels include 'Inshore Traffic Zone', 'Eastgoing 1-hour', 'Westgoing 1 1/2 hours', and 'Eastgoing 4 hours'. The bottom of the map shows the coastline of Morocco with labels like 'Ras el Ma' and 'Ras el Hajar'. + +GIBRALTAR STRAIT – OLD SITUATION (Map 4) + +L.055\_fl.2d + +# **BIBLIOGRAPHY** + +- ITU-T Handbook (2001), *Marinized terrestrial cables*. +- ITU-T Recommendation L.30 (1996), *Markers on marinized terrestrial cables*. +- ITU-T Recommendation G.972 (2000), *Definition of terms relevant to optical fibre submarine cables*. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure, Internet protocol aspects and Next Generation Networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.6-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg b/marked/L/T-REC-L.6-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..64672153e39c851d9e16fdbc702e526c7ba7e8a7 --- /dev/null +++ b/marked/L/T-REC-L.6-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:454a9958ffe168868cb7d38a0eb24418dafe31a7a4245c992089b2316ac37d3e +size 7392 diff --git 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+ +**Optical fibre cable installation by floating +technique** + +ITU-T Recommendation L.61 + +--- + + + +# **ITU-T Recommendation L.61** + +# **Optical fibre cable installation by floating technique** + +## **Summary** + +This Recommendation describes the floating technique to install optical fibre cables in ducts. + +The floating process described in this Recommendation is always performed by means of water. + +It provides considerations on the equipment to be used, and gives advice on steps to be performed, and on procedures and precautions to be taken during the cable installation. + +## **Source** + +ITU-T Recommendation L.61 was approved on 29 July 2004 by ITU-T Study Group 6 (2001-2004) under the ITU-T Recommendation A.8 procedure. + +## **Keywords** + +Air compressor, duct, floating, gradient pressure, water pump. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2004 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +| | Page | +|-----------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 2.1 Normative references..... | 1 | +| 2.2 Informative references..... | 1 | +| 3 Definition..... | 1 | +| 4 Abbreviations..... | 1 | +| 5 Introduction ..... | 2 | +| 6 Floating technique requirements..... | 2 | +| 7 Infrastructures ..... | 3 | +| 7.1 Ducts..... | 3 | +| 7.2 Cable..... | 3 | +| 8 Equipment and settings in floating technique..... | 4 | +| 8.1 Water pump ..... | 4 | +| 8.2 Water tank ..... | 4 | +| 8.3 Cable pushing device (Caterpillar)..... | 5 | +| 8.4 Cable-speed control ..... | 5 | +| 9 Preliminary phases..... | 5 | +| 10 Installation issue ..... | 5 | +| 10.1 Duct setting..... | 5 | +| 10.2 Cable setting ..... | 6 | +| 11 Cable installation ..... | 6 | +| Annex A – Theory ..... | 7 | +| Appendix I – Italian experience ..... | 8 | +| I.2 Bibliography ..... | 10 | + + + +## Optical fibre cable installation by floating technique + +# 1 Scope + +This Recommendation: + +- gives a general description of the machine and operations needed in performing the installation of optical cables as defined in ITU-T Rec. L.10 inside ducts or conduits by means of floating technique; +- provides considerations on infrastructure, floating equipment and setting needed in using such a technique; +- gives advice on the preliminary steps that should be performed; +- gives advice on procedures and precautions to be considered during the cable installation. + +## 2 References + +### 2.1 Normative references + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- ITU-T Recommendation L.1 (1988), *Construction, installation and protection of telecommunication cables in public networks*. +- ITU-T Recommendation L.10 (2002), *Optical fibre cables for duct and tunnel application*. +- ITU-T Recommendation L.35 (1998), *Installation of optical fibre cables in the access network*. +- ITU-T Recommendation L.57 (2003), *Air-assisted installation of optical fibre cables*. + +## 2.2 Informative references + +- ITU-T Handbook on "*Construction, Installation, Jointing and Protection of optical fibre cables*". +- ISO 7611:1985, *Gas chromatographic method on capillary columns*. + +# 3 Definition + +None. + +## 4 Abbreviations + +This Recommendation uses the following abbreviations: + +| | | +|------|------------------------------------------------| +| EKE | PolyEthylene – Aramidic Yarn – PolyEthylene | +| EVE | PolyEthylene – Fibre Glass Yarn – PolyEthylene | +| HDPE | High Density PolyEthylene | + +NPx x bar value of Nominal Pressure + +# 5 Introduction + +The floating technique is based on forcing along the cable route, by means of a pump, a suitable water flow. Moving water exerts a distributed action on the cable that pushes it forward at a speed in the range 30 ÷ 40 m/min. + +There are no pulling forces applied at the front end of the cable: that extremity being completely free (with neither rope nor parachute attached). + +Moreover, the water thrust minimizes the friction effect generated between the cable and the duct during the installation process. + +Besides, because, with this technique, the applied forces on 1 m of cable element are around 0.10-0.15 N/kg, the resultant forces applied on the cable are lower than those applied in the case of the use of pulling techniques, thus reducing the installation hazards. + +Additionally, if the fluid speed is such as to cause, on each cable element, a force greater than that aforesaid, then the presence of bends along the cable route becomes a less significant affecting factor compared with the pulling technique. Fluid speeds of 1 m/s are advisable for heavy optical cables (around 300 kg/km). + +Furthermore, since the density of the water is greater than that of the air, for a given type of cable (weight and diameter), a lower water pressure is requested with respect to the use of the Air-assisted technique. This also allows the laying of cables in ducts designed to withstand a working pressure (NP) of 6 bar (e.g., HDPE NP6 ducts) which would not be suitable in the case of the use of the Air-assisted technique. + +Cables are installed without virtual stress, leaving the cable relaxed in the duct upon completion of the installation. + +Finally, water floating does not cause a significant increase of the duct temperature, providing another advantage over those systems that use gas as a laying element. + +## 6 Floating technique requirements + +The choice of the floating technique depends mainly on: + +- type of cable (diameter, weight, stiffness); +- duct diameter and duct characteristics vs. pressure; +- water availability; +- duct joints characteristics vs. inner pressure; +- shape of the route (number of bends, location of the bends, gradient). + +The maximum length of installed cable, as well as the maximum speed of installation, depend on the aforesaid factors and the equipment used according to the theory shown in Annex A. + +For uphill routes, the weight of the water pushing the cable towards the upper side should be taken into account. It is recommended increasing water pressure of about 1 bar per 10 m drop level. + +If the drop is relevant, the water pressure or increase may be incompatible with maximum pressure to be used with the duct and joints; in such a case, it is convenient to proceed with a downhill laying using a limited water quantity in order to get the allowed range. + +## 7 Infrastructures + +### 7.1 Ducts + +Material and thickness of the ducts and the watertight connectors fitting them should be suitable for the water pressure to be used. A reference value $\geq 6$ bar is recommended. + +In order to prevent unforeseeable friction between duct and cable sheath, it is important to ensure that the duct is in a sound condition (it should keep its circular shape during installation) and as clean and clear as possible. + +Maximum duct diameter depends on the type of machine used. HDPE ducts with an external diameter of 40 ÷ 50 mm, have allowed the installation of cable lengths up to 6000 m. + +NOTE – The use of HDPE ducts having a working pressure of less than NP6 degrees may be possible, but this has to be analysed considering the real application in the field (route length, cable type, route layout, duct inner diameter, duct characteristics vs. pressure). + +### 7.2 Cable + +The maximum of length cable that can be installed is influenced by the stiffness of the cable. A very flexible cable (minimum curvature radius during installation less than 300 mm) can be floated without resistance as long as the bends along the route are greater than this value. A rigid cable may encounter resistance during the laying in the duct if two consecutive bends are closely spaced, (e.g., 50 m). + +Consequently, friction between the cable sheath and the inner duct surface may become another important parameter in case of rigid cable structures. Such a parameter should be as low as possible: a typical value of the dynamic friction coefficient is 0.1. + +Moreover, according to Equation A.2, the lighter the cable is, the further it can be floated, but there is no linear relationship between the cable weight and the floating-in length. + +In order to limit the friction forces between cable and duct, it is recommended to avoid two or more consecutive 90° bends spaced less than 20 m apart, otherwise, the cable stiffness could cause excessive friction corresponding to such bending points. + +To minimize the friction effect, the cable diameter shall not be bigger than 50% of the internal duct diameter. + +In Table 1, the relationships among cable weights, type of ducts and maximum cable length installable for a linear route are shown. + +**Table 1/L.61 – Maximum cable length relative to cable and duct types** + +| Cable weight (kg/km) | Duct types
(HDPE $\phi$ ext 50 mm) | Maximum floating length (m) | +|----------------------|---------------------------------------|-----------------------------| +| 100 | NP6 | 4000 | +| 100 | NP10 | 6000 | +| 200 | NP6 | 3000 | +| 200 | NP10 | 4000 | +| 300 | NP6 | 2000 | +| 300 | NP10 | 3000 | + +# 8 Equipment and settings in floating technique + +The most important parts of the system are: + +- water pump; +- water tank; +- cable pushing device (caterpillar); +- water stream/cable coupling device. + +A communication system (usually a Radio link or mobile phone) shall be deployed for on site communications between the ends of the cable route. + +Figure 1 shows how the parts of the floating machine are assembled. + +![Diagram of the general assembly of the floating machine. It shows a water pump on the left connected to a coupling device, which is connected to a caterpillar pushing device. A cable is being pushed through the coupling device and caterpillar. The caterpillar is mounted on a frame. A large wheel is shown on the right, with a cable being pulled from it. Water flow from the pump is indicated by an arrow pointing towards the cable. The entire assembly is mounted on a truck bed.](61ce9760bffbecba8f5e63310be1ebec_img.jpg) + +The diagram illustrates the assembly of a floating machine for cable installation. On the left, a water pump is connected to a coupling device. This device is followed by a caterpillar pushing mechanism mounted on a frame. A cable is shown being pushed through the coupling and caterpillar. To the right, a large reel of cable is being pulled, with an arrow indicating the direction of rotation. A water flow from the pump is directed towards the cable. The entire setup is mounted on a truck bed, represented by a hatched area at the bottom. Labels with arrows point to the 'coupling device', 'caterpillar', 'cable', and 'water flow from pump'. A small code 'L.061\_F01' is visible in the bottom right corner of the diagram. + +Diagram of the general assembly of the floating machine. It shows a water pump on the left connected to a coupling device, which is connected to a caterpillar pushing device. A cable is being pushed through the coupling device and caterpillar. The caterpillar is mounted on a frame. A large wheel is shown on the right, with a cable being pulled from it. Water flow from the pump is indicated by an arrow pointing towards the cable. The entire assembly is mounted on a truck bed. + +Figure 1/L.61 – General assembly of the floating machine + +### 8.1 Water pump + +It is a motive station mounted on a truck used to generate a high-pressure water flow through the duct route. + +A pump generates a water flow that pushes the cable into the duct. + +By means of Equation A.4, it is possible to calculate the correlation between the speed of the water flow and its pressure. + +Maximum pressure to apply depends on the characteristics of the duct used (see ISO 7611). + +Practical pressure values are in the range of $4 \div 10$ bar. Pressure to be used has to be in accordance with the duct characteristics (see 7.1). + +### 8.2 Water tank + +The capacity of the tank shall be able to supply water for the maximum size of cable to be installed taking into account: + +- duct inner diameter; +- duct length; +- cable diameter; +- cable installation speed; +- fluid speed. + +For example, in a typical installation of 6000 m, about 6000 litres of water are necessary to fill the duct before starting the cable installation, and another 2000 litres are necessary for its laying. + +A truck is then requested on which a water tank of about 8000 litres, assembled with the machinery controller and the cable reel, is loaded. A second tank may be used to recover the incoming water at the far end of the duct route. + +According to local rules, the water inside the duct should be recovered at the end of the cable installation (i.e., by means of an air compressor). + +### **8.3 Cable pushing device (Caterpillar)** + +The water flow and cable shall be directed inside a "flowing room" in order to exert the dragging force on the cable. + +The Flowing Room System shall be used to couple both the cable and the high-pressure fluid flowing into the duct route. This system is positioned at the starting end of the cable laying and located as close as possible to the starting manhole in the duct route. + +A caterpillar shall be used to trigger and regulate the cable installation speed. This is because the speed of cable installation, caused by the motive force of the water flow, is usually too high. The caterpillar makes it possible to stop the cable laying, restart it, and even to reverse the cable laying. + +An example of the coupling mechanism process between the water stream and the cable is shown in Figure I.1. + +### **8.4 Cable-speed control** + +The cable speed shall be controlled by means of a mechanical device (caterpillar) that applies a force on the cable and pushes it into the duct at a controlled speed. An example of a caterpillar is shown in Figure I.2. + +It shall be driven by a motor, provided with a manual and automatic run-stop device. + +A variable speed engine system shall also be used to match the speed of the cable reel to the required laying speed (the recommended laying speed is 40 m/min). + +# **9 Preliminary phases** + +For installations using the floating technique, all precautions considered in other installation techniques such as reels handling, cables, personal security, cable storage in splice point, etc., shall be taken into account. + +To achieve an optimum adaptation between the machine and the cable route, the best location for the placement of the floating machine should be determined. For instance, to minimize the friction effect of the closeness of bends to one end of the laying route, it would be preferable to start the cable installation from the other end. Considerations regarding the presence, along the cable route, of favourable gravitational gradients should also be taken into account. In some cases, the gradient pressure might be too extreme for the duct performance. + +## **10 Installation issue** + +### **10.1 Duct setting** + +The duct shall be jointed at all the intermediate manholes/handholes by means of a piece of duct and watertight connectors with an adequate NP degree. It is recommended setting a piece of duct around the wall in order to leave it for future use, otherwise it has to be removed after laying. + +The maximum pressure that the duct can support for short periods shall not exceed a value of three times the NP degree of HDPE duct (see ISO 7611). Of course, the duct joints shall be able to withstand such a maximum pressure too. + +The duct route shall be controlled and checked by means of a system able to perform a "go/not go" test concerning the real inner diameter of the duct itself. Several methods may be used. The most widely used consists of blowing in the duct a piston or a ball of suitable diameter (around 80% of the inner nominal duct diameter). + +In case of long routes with many bends, it is recommended pouring a proper lubricant into the duct before cable installation. + +### **10.2 Cable setting** + +Before cable laying, the water flow shall be tested in order to control the continuity of the duct and the feasibility of the floating. The water shall completely fill the duct, eliminating any air-pockets. + +The cable, closed at the end with a thermo-restricting sheath, is inserted into the duct free of pulling force by means of a large and fast flowing volume of water coupled to it in the flowing room. + +The water streaming through the duct exerts the thrust on the cable sheath. This force is caused by friction between water particles and cable sheath. + +To achieve good floating performances, the compressor shall have a capacity according to the duct size and its length (e.g., to fill a 4000 m duct having an inner diameter of 43 mm, according to Table 1, it is necessary to supply about 5800 litres of water). + +## **11 Cable installation** + +It has to be taken into account that at least four persons are necessary to perform the installation process: one handling the cable reel and the floating machine; one inserting and controlling the cable into the flowing room, one at the cable reception point, and one to manage all the operations (see Figure 2). + +Once all precautions detailed in the previous paragraphs have been taken and the floating-in machines have been located in the right places, the following is recommended: + +- Preparation of the duct in order to adapt the floating to the duct. +- Checking that the water flow arrives to the remote end of the route, filling the remote end duct section. +- Fitting the cable pushing elements of the floating machine's capstan to the cable diameter. +- Putting the cable in the cable pushing elements of the machine (caterpillar). +- Putting the cable in the floating chamber. +- Introducing the cable in the duct. +- Fixing the cable pushing elements of the machine to the cable. +- Fixing the duct to the pushing in machine with the fitting connector. Making sure the right fitting connector is used in order to avoid water losses during the process. +- Starting up the machine. The water flow generated by the compressor will begin dragging the cable inside the duct. +- At the distant end of the duct, the cable will be received. A remaining length of cable, for cable splicing purposes, shall be stored and protected as usual. +- Installing the first length of the cable in one direction when the cable is installed from an intermediate point. Once it is finished, remove the remaining part of the cable from the drum and lay it on the ground in a figure-of-eight pattern. Special care must be taken in + +order to prevent the cable getting dirty during this phase. Then, place the floating machine in order to allow the installation in the opposite direction and proceed in a similar way as detailed previously. + +- When necessary, the cable may be installed from an intermediate point of the route. +- For difficult sites, the truck containing the floating apparatus shall be connected to the starting manhole by an appropriate length of duct. + +![Schematic layout of cable installation equipment. A drum on the left holds a cable that is being pulled through a conduit. The cable passes through a floating complex and an equipment labeled 'Equip-IN'. The conduit is shown in cross-section, with a 'Water tank' and 'Equip-OUT' on the right side. The label 'L.061_F02' is in the bottom right corner of the diagram.](eefe19c5e14dc4d6c316b7f7fbb7d7d7_img.jpg) + +Schematic layout of cable installation equipment. A drum on the left holds a cable that is being pulled through a conduit. The cable passes through a floating complex and an equipment labeled 'Equip-IN'. The conduit is shown in cross-section, with a 'Water tank' and 'Equip-OUT' on the right side. The label 'L.061\_F02' is in the bottom right corner of the diagram. + +**Figure 2/L.61 – Schematic layout** + +## Annex A + +## Theory + +The rate of water flow necessary to move a cable through a duct route depends on mechanical and physical characteristics of the duct and cable. + +The vertical thrust ( $F_q$ ) on a cable submerged in water is: + +$$F_q = \gamma \cdot \pi \cdot (d/2)^2 \cdot l \cdot g \quad [N] \quad (A.1)$$ + +where: + +$d$ = cable diameter (m) + +$\gamma$ = water density ( $\text{kg/m}^3$ ) + +$l$ = cable length (m) + +$g$ = gravitational acceleration = $9.8 \text{ m/s}^2$ + +The elementary pulling force ( $F_t$ ) to move the cable is: + +$$F_t = \mu \cdot [(p \cdot l \cdot g) - F_q] \quad [N] \quad (A.2)$$ + +where: + +$\mu$ = coefficient of residual friction between cable sheath and duct + +$p$ = longitudinal mass of cable ( $\text{kg/m}$ ) + +Such a formula shows how water is more effective than a gas as laying fluid, being: $F_q \text{ water} \gg F_q \text{ gas}$ . + +The horizontal thrust of the water on the cable is: + +$$F_s = Q \cdot (v - c) = S \cdot \gamma \cdot v \cdot (v - c) \quad [N] \quad (A.3)$$ + +where: + +**Q** = rate of flow (kg/s) + +**v** = water speed (m/s) + +**c** = laying speed (m/s) + +**S** = effective area (duct section minus cable section), (m2) + +The cable floats when: **Fs = Ft** + +$$\mu * [(p * l * g) - F_q] = S * \gamma * v * (v - c) \quad (\text{A.4})$$ + +by solving Equation A.4, it is possible to find the value of **v min** which allows the cable to float. + +For example, using: + +**μ** = 0.1 + +duct inner diameter = 50 mm + +cable diameter = 20 mm + +**c** = 0.5 m/s + +**p** = 0.200 kg/m + +we find an effective minimum water speed: + +$$v \text{ min} = 0.61 \text{ m/s}$$ + +The floating system must be able to get a water flow with a speed greater than **v min**. + +Using **v min = 0.61** m/s in Equation A.4 we find: **Fs = 0.11 N** + +## Appendix I + +## Italian experience + +**I.1** By the end of 2003, around 6000 km of cables have been laid in Italy by using the floating technique. + +The most important features for such installations were: + +- Duct type: HDPE 50 mm external diameter duct with NP6 or NP10 degree; +- Cable type: diameter: 12 ÷ 20 mm; installation minimum curvature radius: 20 times diameter; weight: 0.1 ÷ 0.2 kg/m. Protection structures: EKE, EVE, etc.; +- Floating length (without figure eight procedure): 4000 m of cable; +- Steady applied pressure: < 6 bar for NP6 and < 10 bar for NP10 ducts; +- Short-term applied pressure: 10 bar for NP6; +- Pump max. pressure: >> 10 bar in order to have the possibility of applying a maximum effective pressure of 10 bar at the beginning of the duct; +- Floating Machinery and Devices. + +An idea of the most important coupling mechanism, devices and floating system used are shown in Figures I.1, I.2 and I.3 respectively. + +![Diagram of the coupling mechanism process between the water stream and the cable. It shows a cross-section of a duct (labeled 'Duct') and a flowing chamber (labeled 'Flowing chamber'). A cable (labeled 'Cable') is being pushed into the duct. Dimension A indicates the length of the flowing chamber, and dimension B indicates the height of the duct.](5f2c99ae08864cf2d5c949947bac2b98_img.jpg) + +Duct +A +B +Flowing chamber +Cable +L.061\_FI.1 + +Diagram of the coupling mechanism process between the water stream and the cable. It shows a cross-section of a duct (labeled 'Duct') and a flowing chamber (labeled 'Flowing chamber'). A cable (labeled 'Cable') is being pushed into the duct. Dimension A indicates the length of the flowing chamber, and dimension B indicates the height of the duct. + +**Figure I.1/L.61 – Coupling mechanism process between the +water stream and the cable** + +![Diagram of a caterpillar that applies a force on the cable and pushes it into the duct. It shows a cross-section of the caterpillar mechanism (labeled 'Cable') and the duct (labeled 'Duct'). Dimension B indicates the height of the duct.](d25a962fde4b3171879749757440c3c5_img.jpg) + +B +Cable +L.061\_FI.2 + +Diagram of a caterpillar that applies a force on the cable and pushes it into the duct. It shows a cross-section of the caterpillar mechanism (labeled 'Cable') and the duct (labeled 'Duct'). Dimension B indicates the height of the duct. + +**Figure I.2/L.61 – Caterpillar that applies a force on the +cable and pushes it into the duct** + +![Photograph of a floating system at the near end. It shows a large yellow cable reel on a trailer, with several workers in yellow safety vests and hard hats standing around it. The background shows a green hillside.](33809b11cc711711ebb7be1282fcd4b7_img.jpg) + +L.061\_FI.3 + +Photograph of a floating system at the near end. It shows a large yellow cable reel on a trailer, with several workers in yellow safety vests and hard hats standing around it. The background shows a green hillside. + +**Figure I.3/L.61 – Floating system at near end** + +## **I.2 Bibliography** + +The installation processes have been performed following the guidelines by CIS "Procedimento de apparecchiatura per la posa di cavi entro tubi a mezzo di un fluido idraulico a pressione" (1991-1992). + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure, Internet protocol aspects and Next Generation Networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.64-201210-I_PDF-E/0cc86fe8fc37b0edc9581f2af9459a52_img.jpg b/marked/L/T-REC-L.64-201210-I_PDF-E/0cc86fe8fc37b0edc9581f2af9459a52_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..bc6432832477b23cc23808f26756b91f0bc01ac2 --- /dev/null +++ b/marked/L/T-REC-L.64-201210-I_PDF-E/0cc86fe8fc37b0edc9581f2af9459a52_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:aacd8411999cfc7c504387b3416639f352d2c464e0d8a909f49b459dae808049 +size 11592 diff --git a/marked/L/T-REC-L.64-201210-I_PDF-E/11edb7fcedf09ac6a817f8d7b8c61eec_img.jpg b/marked/L/T-REC-L.64-201210-I_PDF-E/11edb7fcedf09ac6a817f8d7b8c61eec_img.jpg new file mode 100644 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+version https://git-lfs.github.com/spec/v1 +oid sha256:2387c821166665ef8815c0f1fc1f3b4ade4f5ad2ca36b77b9f8b9f4f88ec4a57 +size 67888 diff --git a/marked/L/T-REC-L.73-200804-I_PDF-E/raw.md b/marked/L/T-REC-L.73-200804-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..558ed7eb3b87999447b0b76becc0e7939ab14b6c --- /dev/null +++ b/marked/L/T-REC-L.73-200804-I_PDF-E/raw.md @@ -0,0 +1,482 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.73** + +(04/2008) + +SERIES L: CONSTRUCTION, INSTALLATION AND +PROTECTION OF CABLES AND OTHER ELEMENTS OF +OUTSIDE PLANT + +# --- **Methods for inspecting and repairing underground plastic ducts** + +Recommendation ITU-T L.73 + + + +## **Recommendation ITU-T L.73** + +# **Methods for inspecting and repairing underground plastic ducts** + +## **Summary** + +After a conduit is installed in a trench and has been backfilled, but before any surface construction begins, it is common practice to check duct quality because certain plastic conduits can become oval-shaped, pierced or broken. Recommendation ITU-T L.73 describes inspection methods such as the use of test mandrels and closed-circuit television (CCTV) systems to check duct quality, and also describes various methods that are utilized to repair underground conduits. Repairing methods without digging, called "trenchless techniques" are introduced, and traditional repairing methods (dig and replace) is also presented. Additionally, guidelines for selecting appropriate repairing methods are proposed. It is expected that this Recommendation will provide alternative solutions for inspection and repair work. + +## **Source** + +Recommendation ITU-T L.73 was approved on 6 April 2008 by ITU-T Study Group 6 (2005-2008) under Recommendation ITU-T A.8 procedure. + +## **Keywords** + +CCTV, inspection, mandrel, repair, trenchless techniques, underground duct. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2009 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +| | Page | +|-----------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 2 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 2 | +| 6 Methods for inspecting and repairing underground plastic ducts..... | 2 | +| 6.1 Inspection methods for underground ducts ..... | 2 | +| 6.2 Repairing methods for underground ducts ..... | 4 | +| Appendix I – Korean experience ..... | 9 | +| I.1 Inspection methods ..... | 9 | +| I.2 Repairing methods ..... | 12 | +| Bibliography..... | 13 | + +# **Introduction** + +Placing cables in conduits is preferred because it has a principle advantage that the cable placement operation is separated in time from the actual conduit construction phase. The protection of the cable with the passage of time and the possibility of repeated access, cable removal and delayed cable installation make the method of placing cables in ducts more attractive. The method, however, has a disadvantage in that the initial cost of conduit construction is expensive. It is noted that underground ducts are prone to being deformed by the burden of earth pressure, which makes it necessary to check the ducts before cable installation, and to repair defective ducts before placing cables in conduits. + +## Recommendation ITU-T L.73 + +## Methods for inspecting and repairing underground plastic ducts + +# 1 Scope + +This Recommendation: + +- makes a classification of different methods for inspecting and repairing underground ducts; +- describes both trenchless methods and conventional methods; +- is limited to the methods for underground ducts in which no cables are installed; +- focuses on methods for underground ducts that have single-way duct unit systems and are made of plastic materials such as polyvinyl chloride (PVC) and polyethylene (PE); +- deals with pipes having diameters ranging from 90 to 110 mm. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T L.1] Recommendation ITU-T L.1 (1988), *Construction, installation and protection of telecommunication cables in public networks*. +- [ITU-T L.11] Recommendation ITU-T L.11 (1988), *Joint use of tunnels by pipelines and telecommunication cables, and the standardization of underground duct plans*. +- [ITU-T L.35] Recommendation ITU-T L.35 (1998), *Installation of optical fibre cables in the access network*. +- [ITU-T L.38] Recommendation ITU-T L.38 (1999), *Use of trenchless techniques for the construction of underground infrastructures for telecommunication cable installation*. +- [ITU-T L.39] Recommendation ITU-T L.39 (2000), *Investigation of the soil before using trenchless techniques*. +- [ITU-T L.40] Recommendation ITU-T L.40 (2000), *Optical fibre outside plant maintenance support, monitoring and testing system*. +- [ITU-T L.46] Recommendation ITU-T L.46 (2000), *Protection of telecommunication cables and plant from biological attack*. +- [ITU-T L.48] Recommendation ITU-T L.48 (2003), *Mini-trench installation technique*. +- [ITU-T L.63] Recommendation ITU-T L.63 (2004), *Safety procedures for outdoor installations*. + +# 3 Definitions + +This Recommendation defines the following term: + +**3.1 trenchless technology:** Technology of installing, repairing or renewing underground ducts using methods that minimize or eliminate the need for excavation. The use of such techniques can reduce environmental impact, social costs and at the same time provide economic alternatives to traditional open-cut methods of installation, renewal or repair. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +CCTV Closed Circuit Television + +LVDT Linear Variable Differential Transformer + +PE Polyethylene + +PVC Polyvinyl Chloride + +# 5 Conventions + +None. + +# 6 Methods for inspecting and repairing underground plastic ducts + +## 6.1 Inspection methods for underground ducts + +### 6.1.1 Classification of defects + +Some defects that may occur in plastic ducts are given in Table 1. + +**Table 1 – Classification of defects** + +| Defects | Causes | +|-------------------------|-----------------------------------------------------------------------------------------------------| +| Crack or fracture | Excessive pressure.
Insufficient duct strength. | +| Duct failure | Ground settlement.
Excessive loads. | +| Pointed deformation | Sharp shaped crushed stone. | +| Oval shaped deformation | Excessive pressure.
Insufficient duct strength.
Dynamic compacting loads during construction. | +| Soil intrusion | Disconnection of ducts. | +| Offset | Faulty construction.
Ground settlement. | + +### 6.1.2 Inspection methods + +#### 6.1.2.1 Conventional method + +After the trench has been backfilled, but before any surface construction begins, certain plastic conduits can become oval-shaped, pierced or broken. Accordingly, it is necessary to check for duct deflection before any cable installation. Each duct should allow the passage of a test mandrel consisting of a rod carrying a solid disc. The test mandrel is sized to be smaller than the inside diameter of the duct so that some deflection of the ducts is allowable. The test mandrel can be attached to a pneumatic duct cleaner as shown in Figure 1a. It is possible to perform this operation by simply blowing it inside the duct; it will reach the other end of the duct if no restrictions or obstructions are present. + +Ducts may also be examined by test mandrels as shown in Figure 1b. A test mandrel is pulled through the duct by means of a rope or cable. If the mandrel can be pulled through the tested section, then the section is considered acceptable. If deformations are present and the mandrel gets stuck, the blocked area of conduit can be repaired. The mandrel, however, would have difficulties in checking multiple defective parts if it became stuck as a result of the first defect and could not continue its passage through the duct. In this case, the mandrel is pulled out, and the test is repeated using a smaller one. If the mandrel cannot be pulled through the entire length of the duct, there are several possible reasons. Firstly, the duct may have deflected beyond what the mandrel will tolerate. Secondly, the mandrel may have become caught in the sleeve due to a tight radius. Thirdly, debris may be blocking the path of the mandrel. It is recommended that the cause of the mandrel blockage be ascertained using a closed circuit television (CCTV) system. + +![Figure 1: Test mandrels with duct cleaner. Diagram (a) shows a 'Test mandrel' consisting of a central rod with three spaced-out circular discs, connected to a 'Duct cleaner' which features a 'Skirted seal' at its leading end. Diagram (b) shows a sequence of components connected by 'Steel wire'. From left to right, there is a 'Pulling eye', a 'Mandrel' (an elongated oval shape), a 'Cleaning pad' (consisting of two cup-like elements), and a 'Brush' (a dense cylindrical set of bristles). The assembly is pulled by steel wire from both ends. Label L.73(08)_F01 is in the bottom right.](a86610f7a0e579fec9f34dea52fa088b_img.jpg) + +a) + +b) + +Figure 1: Test mandrels with duct cleaner. Diagram (a) shows a 'Test mandrel' consisting of a central rod with three spaced-out circular discs, connected to a 'Duct cleaner' which features a 'Skirted seal' at its leading end. Diagram (b) shows a sequence of components connected by 'Steel wire'. From left to right, there is a 'Pulling eye', a 'Mandrel' (an elongated oval shape), a 'Cleaning pad' (consisting of two cup-like elements), and a 'Brush' (a dense cylindrical set of bristles). The assembly is pulled by steel wire from both ends. Label L.73(08)\_F01 is in the bottom right. + +**Figure 1 – Test mandrels with duct cleaner** + +#### 6.1.2.2 CCTV method + +As an alternative, a more precise inspection can be performed using a CCTV system with a semi-rigid cable which allows the camera to be pushed through the duct from an access point. The quality of the duct can be assessed by viewing the image continuously. It should be noted that duct inspection using only CCTV cameras is inherently subjective by nature and therefore of limited value. To accurately measure features within a duct and to provide an objective assessment, an innovative technology has been developed recently. Laser profiling technology can provide precise + +measurements of duct parameters such as "ovality", unobstructed cross-sectional area, and duct deformations. + +#### 6.1.2.3 Other methods + +CCTV systems, however, may not always provide a clear image, for example when the duct contains dirty water. When it is not possible to measure the internal condition accurately and to detect defects reliably with a standard CCTV camera, other methods may be required to measure the inside diameter and profile of the duct. + +## 6.2 Repairing methods for underground ducts + +### 6.2.1 Selection of repairing methods + +Until now, many methods used to repair and/or rehabilitate essential services such as telecommunication, electricity, water mains, sewer and gas lines have been developed worldwide. A classification of repair methods is given in Table 2 and brief descriptions of each technique follow. + +**Table 2 – Duct repair methods** + +| Test | | Inspection by CCTV
(Note 2) | Potential
repairing
methods | +|-------------------------------------------------------|-------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Duct rod
(Note 1) | Mandrel | | | +| Can pass the whole length without any difficulties | Can pass the whole length without any difficulties | The whole length of duct is clean and does not have any defects. | No need to repair | +| | | Debris or sludge that may block test mandrel is observed inside a duct. | High pressure water jetting | +| Can pass the whole length without any difficulties | Cannot pass the whole length without any difficulties | If defective parts such as cracks, duct failure, oval-shaped deformation, and offset are observed, it is considered that the defective parts are not severe and are limited to a small extent. | Conventional methods (dig and replace).
Methods for removing irregularities or enlarging a duct:
– re-rounding method;
– robotic repair system. | +| Cannot pass the whole length without any difficulties | | If the CCTV camera cannot pass because of blockage or obstruction, it is considered that the defects are severe and affect a large section of the duct. | Conventional method (dig and replace method).
Pipe bursting and/or splitting method. | + +NOTE 1 – A duct rod is a tool that is used to manually insert pulling lines through the duct. +NOTE 2 – Inspection by CCTV is applied only when the mandrel cannot pass due to defects in the duct. + +### 6.2.2 Conventional method + +The conventional repair methods are "open-cut" or "dig-and-replace". These methods involve direct replacement of the defective section with a new duct in the open-cut trenches as shown in Figure 2. Repair procedures that are usually used are as follows: + +- Remove a sufficient amount of backfill material to completely expose the damaged duct, and also provide adequate working space in the trench. Cut out the damaged portions of the ducts (step 1). +- Cut the replacement section from a piece of duct with the same outside diameter and wall thickness. Thoroughly clean the exposed ends of the fixed duct and both ends of the replacement section. Slide the repair (or sleeve-type) couplings over the ends of the fixed duct (step 2). +- Mark lines around the ends of the replacement section, one half the length of the repair coupling away from the ends, in order to centre the repair couplings. Apply adhesive on both ends of the replacement section and on the exposed ends of the fixed duct (step 3). +- Place the repair section into the duct line and centre the repair couplings over the joints to the lines marked on the replacement section. Rotate the couplings approximately one-quarter turn to distribute the adhesive (step 4). + +![Figure 2 – Conventional duct repairing method. The figure consists of four diagrams labeled a) Step 1, b) Step 2, c) Step 3, and d) Step 4. Step 1 shows a cross-section of a duct with a 'Damaged section' in the middle. The ends of the duct are labeled 'Cut ends square'. Step 2 shows the damaged section removed and two 'Repair couplings' (shaded rectangular blocks) placed over the remaining duct ends. Step 3 shows a 'Replacement section' (a new piece of duct) being inserted between the couplings. An arrow labeled 'Apply adhesive' points to the interface between the couplings and the duct. Step 4 shows the final assembly with the couplings centered over the joints and the replacement section in place.](3668a836db39d25d24b56180a9c9a7fb_img.jpg) + +Figure 2 – Conventional duct repairing method. The figure consists of four diagrams labeled a) Step 1, b) Step 2, c) Step 3, and d) Step 4. Step 1 shows a cross-section of a duct with a 'Damaged section' in the middle. The ends of the duct are labeled 'Cut ends square'. Step 2 shows the damaged section removed and two 'Repair couplings' (shaded rectangular blocks) placed over the remaining duct ends. Step 3 shows a 'Replacement section' (a new piece of duct) being inserted between the couplings. An arrow labeled 'Apply adhesive' points to the interface between the couplings and the duct. Step 4 shows the final assembly with the couplings centered over the joints and the replacement section in place. + +**Figure 2 – Conventional duct repairing method** + +Although conventional methods are simple and reliable, they involve social and traffic costs, including the following: + +- Social cost: + - a) road damage; + - b) damage to adjacent utilities; + +- c) damage to adjacent structures; + - d) noise and vibration; + - e) air pollution; + - f) vehicular traffic disruption; + - g) pedestrian safety; + - h) business loss; + - i) site safety; + - j) citizen complaints; + - k) environmental impact. +- Cost of vehicle or traffic disruption: +- a) cost of fuel; + - b) cost of travel time; + - c) road damage; + - d) vehicular wear. + +When the costs described above are not negligible, it is recommended to use trenchless techniques. + +### **6.2.3 High pressure water jetting** + +The main purpose of this technique is to wash out debris or sludge, which may block a test mandrel, with a high-pressure water-jet. A nozzle for cleaning inside the duct, which is attached to high-pressure hose, is designed to be self-propelled within the duct being cleaned with the help of the reaction force of the discharged high-pressure water. + +### **6.2.4 Method for removing irregularities or enlarging an underground duct** + +This method re-rounds deformed sections of duct by the insertion of an expansion device. The expander system is inflated with hydraulic pressure. The device consists of a cylindrical housing corresponding approximately to the diameter of the duct, a number of expanding members and a conical wedge driven by an axial hydraulic ram. The device is drawn through the duct with its members in a retracted position, and the ram is operated to force the members outward against the wall of the duct to remove irregularities or re-round the deformed part of the duct. The members are then retracted as the device is drawn forward to the next obstruction by means of pulling force. + +### **6.2.5 Robotic repair system** + +A remote controlled device with CCTV monitoring is used for the localized repair of defects and obstructions using grinding tools. This system removes obstructions and intrusions and also mills out cracks to provide a good surface. The hydraulically driven grinding head can be fitted with various shapes of cutter to cope with most obstructions. The operation of these self-propelled robots is monitored by a CCTV camera attached to a head. + +### 6.2.6 Re-rounder method + +This method can restore deflected ducts by pneumatic vibrator as shown in Figure 3. A powerful high frequency vibration consolidates and stabilizes material around the duct which corrects the deformation. The ducts must be cleaned before re-rounding and need to be relatively straight, as the device may not go through small-radius bends. + +![Diagram of the re-rounder method showing a deflected duct being restored by a pneumatic vibrator.](bb6d33498937738ff5dac8d91c9ebaad_img.jpg) + +The diagram shows a cross-section of a duct that has been deflected downwards. A re-rounder tool, consisting of a conical head and a cylindrical body, is shown inside the duct. The tool is connected to a pneumatic vibrator. The surrounding soil is depicted with hatching. A label 'L.73(08)\_F03' is in the bottom right corner. + +Diagram of the re-rounder method showing a deflected duct being restored by a pneumatic vibrator. + +Figure 3 – Re-rounder + +### 6.2.7 Pipe-bursting method + +The pipe-bursting technique is used to replace worn out gas, water or sewer pipelines that may be fractured without digging. A cone-shaped tool ("bursting head") is inserted into the existing pipe and forced through it, fracturing the pipe. At the same time, a new pipe is pulled through. The new pipe can be of the same size or larger than the replaced pipe. The rear of the bursting head is connected to the new pipe, and the front end of the bursting head is connected to a winching cable. As this method may have a detrimental effect on adjacent pipes, it is recommended that this method be applied to single duct lines, and used with caution. In addition, buried object detection is required. A typical pipe-bursting operation layout is illustrated in Figure 4. + +![Diagram of the pipe-bursting method showing the layout of the operation.](ddc7460821484f1ae2835c67955c554c_img.jpg) + +The diagram illustrates the pipe-bursting process. An 'Insertion pit' on the left shows the 'Replacement pipe' being introduced. The 'Old pipe' is being fractured by a 'Bursting head' as it moves through it. 'Lateral connections' to the old pipe are shown being displaced. A 'Temporary bypass' is indicated above the old pipe. At the 'Reception pit' on the right, the 'Pulling cable' is connected to a 'Winch' that pulls the new pipe and bursting head through. A label 'L.73(08)\_F04' is in the bottom right corner. + +Diagram of the pipe-bursting method showing the layout of the operation. + +Figure 4 – Pipe-bursting method + +### 6.2.8 Pipe-splitting method + +Pipe splitting is a similar technique to pipe bursting but is used on non-fragmenting pipes such as steel, ductile iron or polyethylene. The technique is generally the same, but instead of the bursting head, this method uses a splitter, which cuts the existing pipe along one line on the bottom and opens it out, rather than fracturing it (see Figure 5). The splitter is pulled through the existing pipe by either a wire rope or steel rods. The splitting and opening of the existing pipe creates a hole, and the new pipe is pulled immediately behind the splitter. Like the pipe bursting method, it is recommended that this method be applied to single duct lines, with caution and using buried object detection. + +![Diagram of the pipe-splitting method showing a longitudinal cross-section and a cross-sectional view of the tool.](4801720824e4b5e2361a5564f91cfb70_img.jpg) + +The diagram illustrates the pipe-splitting method. The left side shows a longitudinal cross-section of a ductile pipe being split to accommodate a new PE pipe. A pulling rod is connected to the left end of the ductile pipe. Cutting wheels are positioned to split the pipe. A sail blade is shown at the transition point. An expander is located between the ductile pipe and the new PE pipe. A pneumatic hammer is shown at the right end of the new PE pipe. The right side shows a cross-sectional view of the tool, including the original pipe, the expanded split pipe, a cutting wheel, sail blades, and the body. + +Diagram of the pipe-splitting method showing a longitudinal cross-section and a cross-sectional view of the tool. + +L.73(08)\_F05 + +**Figure 5 – Pipe-splitting method** + +# Appendix I + +## Korean experience + +(This appendix does not form an integral part of this Recommendation) + +## I.1 Inspection methods + +Figure I.1 shows various defect images that were captured by a CCTV system developed in Korea. It has been found that the pointed and oval-shaped deformations (Figure I.1c and I.1d) constitute about 60% of all plastic duct defects. + +![CCTV image of a duct with a crack.](be217a121b8cc1b82eb1598749372865_img.jpg) + +A CCTV image showing the interior of a duct. A vertical crack is visible on the upper wall, and a horizontal crack is visible on the lower wall. The duct has a ribbed texture. + +CCTV image of a duct with a crack. + +Crack + +![CCTV image of a duct failure.](0a5acc4b370bb711096e04f25b8b3feb_img.jpg) + +A CCTV image showing a large, irregular opening in the duct wall, indicating a failure. The surrounding area appears rough and damaged. + +CCTV image of a duct failure. + +Duct Failure + +![CCTV image of a pointed deformation.](349cffebeefaae56d9034d3fe65bf7c6_img.jpg) + +A CCTV image showing a sharp, triangular indentation or deformation on the inner wall of the duct. A red circle is drawn around the deformation to highlight it. + +CCTV image of a pointed deformation. + +Pointed deformation + +![CCTV image of an oval-shaped deformation.](ded1520e45c0c3e4c46c58984602bf0e_img.jpg) + +A CCTV image showing a smooth, oval-shaped indentation on the inner wall of the duct. A red circle is drawn around the deformation to highlight it. + +CCTV image of an oval-shaped deformation. + +Oval-shaped deformation + +![CCTV image of soil intrusion.](d965cef420f66e64ad9fe952a070ed84_img.jpg) + +A CCTV image showing a large accumulation of soil and debris at the bottom of the duct, partially obscuring the view. A white circular object is visible on the left side. + +CCTV image of soil intrusion. + +Soil intrusion + +![CCTV image of an offset.](90120cdfd5dc10df8e675ecd61f26db5_img.jpg) + +A CCTV image showing a misalignment or offset in the duct structure. A white circular object is visible on the left side, and the duct wall appears to be shifted. + +CCTV image of an offset. + +Offset + +L.73(08)\_FI.1 + +Figure I.1 – Defects in ducts + +Besides the CCTV system, a new inspection method has been developed using sensors that can measure the inside duct diameter precisely. Sensors, called linear variable differential transformers (LVDTs), are connected to the wheels of the inspection device. There are eight wheels attached to the device: four front wheels and four rear wheels, as shown in Figure I.2a. Each wheel is connected to an LVDT sensor that transforms the displacement into a digital signal. The CCTV camera attached to the head of the device provides an internal image of the duct. Figure I.2b is a diagrammatic section showing the layout of an inspection, and Figure I.2c is the typical graphic display of this system. The advantage of this device is that the profile of the duct is provided and, at the same time, the minimum and maximum diameter can be monitored continuously. + +![3D CAD model of the inspection device showing the rear wheels, front wheels, and a CCTV camera mounted on a long cylindrical body.](ac852a162572ca8a8c8478c49b571af5_img.jpg) + +3D CAD model of the inspection device showing the rear wheels, front wheels, and a CCTV camera mounted on a long cylindrical body. + +a) Perspective view of the device + +![Photograph of the physical inspection device, including a green control cart with a monitor and a separate camera unit connected by cables, positioned next to a long metal duct.](93afce28d7dec5b2202789b31b4ef8ab_img.jpg) + +Photograph of the physical inspection device, including a green control cart with a monitor and a separate camera unit connected by cables, positioned next to a long metal duct. + +b) Layout of inspection + +![Screenshot of the 'Digital Mandrel V1.0' software interface showing real-time measurement data, a list of anomalies, and a graph of diameter (mm) vs. distance (m).](fdcfba1180dc160c7d539c5fb2a6c1e6_img.jpg) + +**실시간 측정 데이터** + +| | | | | | | | +|----|-------|----|---------|--------|----|------| +| X1 | 109.0 | mm | 진입거리 | 104.40 | m | Zero | +| X2 | 85.0 | mm | | | | | +| Y1 | 97.5 | mm | 최소직경/거리 | 84.5 | mm | | +| Y2 | 101.0 | mm | | | | | + +**진입거리** 104.40 m + +**최소직경/거리** 84.5 mm + +**측정계시** + +불량 관로 데이터 + +C 등급 이하의 데이터 없습니다. 19 개 + +| 진입거리(m) | 최소직경(mm) | 등급 | +|---------|----------|----| +| 57.70 | 90.5 | X2 | +| 70.10 | 90.0 | X2 | +| 82.30 | 89.0 | Y1 | +| 82.40 | 89.0 | Y1 | +| 100.00 | 87.0 | X2 | +| 103.90 | 90.5 | X2 | +| 104.00 | 89.0 | X2 | +| 104.10 | 90.5 | X2 | +| 104.20 | 91.0 | X2 | +| 104.30 | 89.0 | X2 | +| 104.40 | 85.0 | X2 | +| 104.50 | 84.5 | X2 | +| 104.60 | 87.5 | X2 | + +**노른2지구2공구 R1-7-2M\_1-7-1M 4번공.xls** + +Graph: 내경(mm) vs. 거리(m) + +Data(mm): 54.5, 54.5, 54.5, 54.5, 54.5, 54.5, 54.5, 54.5 + +1. 작업자 : 김동준 + 2. 현장 정보 : 노른2지구2공구 1무7무3M\_1무6무9M 3번공 + 3. 관로 검사 거리 : 250 m 4. 실측정 거리 : 111.1 m + +Screenshot of the 'Digital Mandrel V1.0' software interface showing real-time measurement data, a list of anomalies, and a graph of diameter (mm) vs. distance (m). + +c) Graphic display + +Figure I.2 – Duct inspection method + +## I.2 Repairing methods + +Based on the method discussed in clause 6.2.4, an expansion device has been developed to remove irregularities or enlarge an underground duct. This method re-rounds the deformed part of the duct. The expander device is inflated with hydraulic pressure. The device consists of a cylindrical housing corresponding approximately to the required diameter of the duct, six expanding plates, and three conical wedges as shown in Figure I.3a. In operation, the device is drawn through the duct with plates and wedges in a retracted position, and is operated to force the plates and wedges outward against the wall of the duct as shown in Figure I.3b. The plates and wedges are then retracted as the device is drawn forward to the next obstruction by means of pulling force. It is estimated that the maximum force to expand is about 100 kN. A CCTV system is attached to the device in order to control the repair work remotely. + +![Figure I.3a: Technical drawings of the expansion device. It includes a side-view schematic with dimension lines, two circular cross-sectional views showing the internal radial arrangement of six plates and three wedges, and a 3D wireframe perspective view of the cylindrical assembly.](97fe9069356cc2a84e8e70673e405958_img.jpg) + +Expanding plates                      Expanding wedges + +Figure I.3a: Technical drawings of the expansion device. It includes a side-view schematic with dimension lines, two circular cross-sectional views showing the internal radial arrangement of six plates and three wedges, and a 3D wireframe perspective view of the cylindrical assembly. + +a) Front, side and perspective views of an expansion device + +![Figure I.3b: 3D rendered models showing the expansion device operation. The 'Before expand' model shows a compact cylindrical tool with purple and red components tucked in. An arrow points to the 'After expand' model, where the purple plates and red/orange conical wedges have moved radially outward, increasing the overall diameter of the tool.](8b4950bfee921d4b61936f6830644edf_img.jpg) + +Before expand +After expand + +Figure I.3b: 3D rendered models showing the expansion device operation. The 'Before expand' model shows a compact cylindrical tool with purple and red components tucked in. An arrow points to the 'After expand' model, where the purple plates and red/orange conical wedges have moved radially outward, increasing the overall diameter of the tool. + +b) Expansion device operation + +**Figure I.3 – Expansion device** + +# Bibliography + +- [b-ITU-T Construction] ITU-T Handbook (1994), *Construction, Installation, Jointing and Protection of Optical Fibre Cables*. +- [b-ITU-T Plant] ITU-T Handbook (1991), *Outside Plant Technologies for Public Networks*. +- [b-Bhavani] Bhavani, S., Gangavarapu, Mohammad Najafi, and Salem, O. (2004), *Quantitative Analysis and Comparison of Traffic Disruption Using Open-Cut and Trenchless Methods of Pipe Installation*, North American Society for Trenchless Technology (NASTT), NO-DIG 2004, New Orleans, Louisiana. +- [b-TTC 2001.02] TTC Technical Report 2001.02, *Guidelines for Pipe Bursting*. +<[http://www.ttc.latech.edu/publications/guidelines\\_pb\\_im\\_pr/bursting.pdf](http://www.ttc.latech.edu/publications/guidelines_pb_im_pr/bursting.pdf)> +- [b-Wirahadikusumah] Wirahadikusumah, R., Abraham, D.M., Iseley, T., and Prasanth, R.K., (1998), *Assessment technologies for sewer system rehabilitation*, Automation in Construction, Vol. 7, No. 4, May; pp. 259-270. +- [b-Kim] Kim, H.W., and Kim, D.H. (2005), *Assessment and repairing technologies for telecommunication conduit*, 23rd International Conference and Exhibition, Ahoy Rotterdam, The Netherlands, September. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git 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b/marked/L/T-REC-L.75-200805-I_PDF-E/raw.md @@ -0,0 +1,561 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.75** + +(05/2008) + +SERIES L: CONSTRUCTION, INSTALLATION AND +PROTECTION OF CABLES AND OTHER ELEMENTS OF +OUTSIDE PLANT + +--- + +**Test, acceptance and maintenance methods of +copper subscriber pairs** + +Recommendation ITU-T L.75 + + + +# **Recommendation ITU-T L.75** + +## **Test, acceptance and maintenance methods of copper subscriber pairs** + +## **Summary** + +The new generation of digital subscriber line (xDSL) demands definition of new requirements and test and maintenance methods. + +The test method, the object of Recommendation ITU-T L.75, aims at simplifying the task of measuring metallic cables and broadband access networks and at ensuring the integrity of services carried over them. + +## **Source** + +Recommendation ITU-T L.75 was approved on 29 May 2008 by ITU-T Study Group 6 (2005-2008) under Recommendation ITU-T A.8 procedure. + +## **Keywords** + +Copper cable requirements for broadband transmission, indoor and outside broadband networks qualification, xDSL. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2009 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +| | Page | +|--------------------------------------------------------------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 4 Abbreviations and acronyms ..... | 1 | +| 5 Conventions ..... | 2 | +| 6 Metallic cables and access network test, acceptance and maintenance methods,
intended for service quality assurance ..... | 2 | +| 6.1 Spectral emulation method (SEM) foundation..... | 2 | +| 6.2 Test and acceptance procedures ..... | 2 | +| 6.3 Maintenance ..... | 3 | +| Appendix I – Traditional test methods and SEM comparison ..... | 4 | +| I.1 Introduction ..... | 4 | +| I.2 Spectral emulation method (SEM) ..... | 7 | +| I.3 Two methods comparison..... | 9 | +| I.4 Method validation..... | 10 | +| Appendix II – Brazilian experience ..... | 11 | +| II.1 Network architecture ..... | 11 | +| II.2 Test and acceptance procedure ..... | 15 | +| Bibliography..... | 16 | + + + +# Recommendation ITU-T L.75 + +## Test, acceptance and maintenance methods of copper subscriber pairs + +# 1 Scope + +This Recommendation describes a methodology to qualify metallic cables for broadband use, before and after their installation on access networks. The qualification process is based on measurements of transmission rate (TR) carried out on the worst possible use condition of the cables, i.e., when all pairs are transmitting at the same time. + +This methodology is known as the spectral emulation method (SEM) and can be applied to qualify modern broadband networks and old telephone networks used to carry xDSL signals. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T G.992.5] Recommendation ITU-T G.992.5 (2005), *Asymmetric digital subscriber line (ADSL) transceivers – Extended bandwidth ADSL2 (ADSL2plus)*. + +[ITU-T G.993.2] Recommendation ITU-T G.993.2 (2006), *Very high speed digital subscriber line transceivers 2 (VDSL2)*. + +# 3 Definitions + +None. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|----------|--------------------------------------------| +| ADSL | Asymmetric Digital Subscriber Line | +| B | Bandwidth | +| DSLAM | Digital Subscriber Line Access Multiplexer | +| FEXT | Far-End CrossTalk | +| IL | Insertion Loss | +| IPTV | Internet Protocol TeleVision | +| NEXT | Near-End CrossTalk | +| N-PSD | Noise Power Spectral Density | +| PSD | Power Spectrum Density | +| PSELFEXT | Power Sum Equal Level Far-End CrossTalk | +| PSNEXT | Power Sum Near-End CrossTalk | +| SEM | Spectral Emulation Method | + +| | | +|------|----------------------------------------------------| +| S/N | Signal-to-Noise ratio | +| TR | Transmission Rate | +| VP | Victim Pair | +| xDSL | General representation for Digital Subscriber Line | + +# 5 Conventions + +None. + +# 6 Metallic cables and access network test, acceptance and maintenance methods, intended for service quality assurance + +## 6.1 Spectral emulation method (SEM) foundation + +Crosstalk is a critical factor in channel capacity evaluation. The summation of all crosstalk (unwanted) signals coupling in a determinate cable pair from all other pairs is the main factor that increases noise. In order to evaluate this parameter, power sum calculations are performed using near- and far-end crosstalk measurements. Annex A shows a drawback associated with these measurements and calculations and the advantage of the SEM. + +SEM is based on Nyquist and Shannon theories, which state that the channel capacity is related to bandwidth, signal-to-noise ratio, and the number of symbols used to modulate each carrier (tone). + +Nyquist: $C = 2 B \log_2 n$ + +Shannon: $C = B \log_2 [1 + S/N]$ + +B: Bandwidth + +S/N: Signal-to-noise ratio + +n: number of symbols + +SEM consists of feeding all cable pairs, except the one selected as a victim pair (VP), with controlled xDSL signals. Transmission rate (TR), noise power spectral density (N-PSD) and signal-to-noise ratio (S/N) on the VP are then measured, instead of evaluating cross-talk, power-sums, impedance, return loss, insertion loss, capacitance, resistance, resistance unbalance, capacitance unbalance, etc. The impact of all these parameters will be reflected in the TR measurements. This process is repeated, switching the VP, until all cable pairs have been measured. + +## 6.2 Test and acceptance procedures + +Acceptance of all access networks used with xDSL systems is recommended before providing any wideband service. To do that, test performance must be executed on groups of up to 600 pairs. + +Also, before installing any new cable on a new network, all pairs, in groups of up to 100 pairs, are recommended to be measured to avoid detecting problems when they are already installed. + +A 100-pair test procedure is based on the following algorithm: + +- Feed pairs number 2 to 100, at the near-end side, with non-coherent signals, with power spectrum density (PSD) limited according to the xDSL technology being evaluated (e.g., Figure B.1 of [ITU-T G.992.5] defines the PSD mask limit for an ADSL2plus operation; see also [ITU-T G.993.2] for VDSL PSD definition). At the far-end side, these pairs must be properly terminated on a resistive load defined as the xDSL impedance level (e.g., 100 $\Omega$ for ADSL2plus). Those pairs are called disturbing pairs. +- Connect one DSLAM port at the near-end side and a modem at the other side of the pair number 1, selected as the VP. Pair 1 is, then, the pair under test. + +- c) Measure the VP TR and S/N. Save these measurements on a database. +- d) Disable DSLAM port and switch the VP far-end side from the modem to a spectrum analyser. Measure and save the N-PSD on the database. +- e) Select another VP and switch it to the set DSLAM/modem. It becomes the new VP. Feed the former VP with the full bandwidth spectrum signal, as in the first step a. +- f) Repeat steps c and d until all pairs have been measured. +- g) The minimum test report must include: + - i) Cable identification. + - ii) Cable length. + - iii) Local temperature. When testing cables on laboratories, room temperature must be controlled and stabilized in the range of $20 \pm 5^\circ\text{C}$ . Care must be taken to ensure that the cable internal temperature has reached room temperature. + - iv) A graphic and a list of all pairs and their respective TRs and S/Rs, ordered from the one with the highest TR (fastest pair) to the one with the lowest TR (slowest pair). + - v) N-PSD must be kept saved on the database for maintenance purposes, addressed in step d above. + +The test procedure for networks is similar, except that the far-end side pairs can be located in distinct ending boxes or cabinets. Remote test modules, capable of being remotely controlled, must be used to switch the far-end side of the pairs to modems, terminating loads and spectrum analysers. + +Automatic test equipment is recommended to: speed up the test process; save test reports in a database for traceability and statistics purposes; and to guarantee the necessary reliability. + +In the case of cable tests, it is mandatory to measure both cable sides in order to evaluate the upstreams and downstreams for xDSL applications. + +For network tests, once cables have been previously measured, downstream measurement is enough. + +The requirements shall be expressed as the minimum TR value, and agreed between the supplier and customer. + +See Appendix I for a comparison of this method with other traditional methods. + +## 6.3 Maintenance + +After testing, comparing results with requirements and accepting the network, broadband service can then be provided and, then, a reliable service quality *maintenance* strategy must be carried out. A proper form to implement it is to enquire periodically the TR of each working port of all DSLAMs, compare them with values obtained during the acceptance process, and alarm in cases of performance degradation and faults. + +Inspection points, capable of switching any pair to a test bus, are recommended to be installed on terminal boxes and cabinets. They will provide easy access to cables (or wires) connected to both sides of the boxes or cabinets when field maintenance becomes necessary. TR, S/N and, especially N-PSD, can be measured and compared to the previous measurements collected during the network acceptance. + +Additional to the above-mentioned measurements, impulsive noise is also recommended to be measured and saved on the database, especially due to its importance to Internet protocol television (IPTV) service quality. + +## Appendix I + +## Traditional test methods and SEM comparison + +### I.1 Introduction + +Depending on the type of multiplex used on a determined DSL technology, frequency or time, it is necessary to measure, in cables and access networks, far-end crosstalk (FEXT), near-end crosstalk (NEXT) or both. + +NEXT is a measure of the unwanted signal coupling from a transmitter at the near-end into neighbouring pairs measured at the near-end side. NEXT is measured for all pair combinations in a cable group. + +Power sum NEXT (PSNEXT) calculation takes into account the combined crosstalk on a receive pair from all near-end disturber pairs operating simultaneously. + +Similarly, equal level far-end crosstalk (ELFEXT) is the measure of the unwanted signal coupling from a transmitter at the far-end into neighbouring pairs measured at the near-end. Power sum ELFEXT (PSELFEXT) is calculated based on the combined crosstalk on a receive pair from all far-end disturbers operating simultaneously. + +It is important to notice that ELFEXT is actually the far-end crosstalk (FEXT) minus disturbing pair insertion loss (IL). + +To calculate the PSNEXT of a 100-pair cable, it is necessary to measure the cross-talk of the 2-combination of those 100 pairs. The number of $k$ -combinations (each of size $k$ ) from a set $S$ with $n$ elements (size $n$ ) can be determined with the binomial coefficient: + +$$\binom{n}{k} = \frac{n!}{k!(n-k)!}$$ + +Calculating this binomial for $n=100$ and $k=2$ , results in 4950 combinations. + +Besides that, the total number of frequency points within the specified bandwidth shall be a minimum of 100 times the number of decades covered by the frequency range. + +As an example, for a 0.1-8 MHz xDSL cable, it will be necessary to measure for each of the 4950 pair combinations, a minimum of 200 frequency points, resulting in 990 000 measurements. + +For PSELFEXT, the problem is worse. As ELFEXT between, for example, pair $n$ and pair $p$ – $\text{ELFEXT}_{(n, p)}$ – is different from $\text{ELFEXT}_{(p, n)}$ , the latter should also be measured, doubling the total number of crosstalk measurements. It is also necessary to measure the 100-pair attenuations. Taking all that into account, 2 000 000 frequency measurements will have to be done just to calculate ELFEXT and PSELFEXT. + +Considering this fact, even with automatic test systems, it is impractical to evaluate PSELFEXT and PSNEXT on all cables that come out of a production line. Normally, cable manufacturers test only samples of groups on samples of cables. In other words, cables are poorly evaluated when they need, for the purpose of data transmission, to be fully evaluated. + +Figures I.1, I.2 and I.3 illustrate the plots of 100-pair PSNEXT, IL and PSELFEXT of an 8 MHz xDSL cable. + +![Line graph showing Insertion loss [dB/100 m] vs Frequency [Hz] for an 8 MHz xDSL cable. The graph includes a red curve for the worse case, a thick black curve for the specification, and a thin grey curve for the margin. The x-axis ranges from 300.0 k to 8.5 M Hz, and the y-axis ranges from 0.9 to 6.3 dB/100 m.](d48475a25698b1c0592e4cfe07138f2a_img.jpg) + +**Insertion loss** + +Worse case [dB/100 m]: 1.01 Frequency [kHz]: 300.00 Specification [dB/100 m]: 1.40 Margin [dB/100 m]: 0.39 + +L.75(08)\_Fl.1 + +Line graph showing Insertion loss [dB/100 m] vs Frequency [Hz] for an 8 MHz xDSL cable. The graph includes a red curve for the worse case, a thick black curve for the specification, and a thin grey curve for the margin. The x-axis ranges from 300.0 k to 8.5 M Hz, and the y-axis ranges from 0.9 to 6.3 dB/100 m. + +**Figure I.1 – Insertion Loss of 8 MHz xDSL cable** + +![Graph of PSNEXT showing multiple black lines representing individual measurements and a red line representing the worst case. The y-axis is [dB/100 m] from -71.2 to -31.0, and the x-axis is Frequency [Hz] from 150.0 k to 8.5 M. The red line starts at approximately -61 dB/100 m at 150 kHz and rises to about -31 dB/100 m at 8.5 MHz. The black lines are clustered between -71.2 and -34 dB/100 m at 8.5 MHz.](36ac3e730a00d3f42d3400f5709f641a_img.jpg) + +**PSNEXT** + +Worse case [-dB]: 35.70 Frequency [kHz]: 6300.00 Specification [-dB]: 34.00 Margin [dB]: 1.71 + +L.75(08)\_Fl.2 + +Graph of PSNEXT showing multiple black lines representing individual measurements and a red line representing the worst case. The y-axis is [dB/100 m] from -71.2 to -31.0, and the x-axis is Frequency [Hz] from 150.0 k to 8.5 M. The red line starts at approximately -61 dB/100 m at 150 kHz and rises to about -31 dB/100 m at 8.5 MHz. The black lines are clustered between -71.2 and -34 dB/100 m at 8.5 MHz. + +**Figure I.2 – PSNEXT** + +![Graph of PSELFEXT showing multiple black lines representing individual measurements and a red line representing the worst case. The y-axis is [dB/100 m] from -73.0 to -25.0, and the x-axis is Frequency [Hz] from 150.0 k to 8.5 M. The red line starts at approximately -61 dB/100 m at 150 kHz, rises to -34 dB/100 m at 2 MHz, and then continues to rise to about -25 dB/100 m at 8.5 MHz. The black lines are clustered between -73.0 and -34 dB/100 m at 8.5 MHz.](f176174c2978785e86a8352bd45e322e_img.jpg) + +**PSELFEXT** + +Worse case [-dB/100 m]: 45.47 Frequency [kHz]: 2000.00 Specification [-dB/100 m]: -42.00 Margin [dB/100 m]: 3.47 + +L.75(08)\_Fl.3 + +Graph of PSELFEXT showing multiple black lines representing individual measurements and a red line representing the worst case. The y-axis is [dB/100 m] from -73.0 to -25.0, and the x-axis is Frequency [Hz] from 150.0 k to 8.5 M. The red line starts at approximately -61 dB/100 m at 150 kHz, rises to -34 dB/100 m at 2 MHz, and then continues to rise to about -25 dB/100 m at 8.5 MHz. The black lines are clustered between -73.0 and -34 dB/100 m at 8.5 MHz. + +**Figure I.3 – PSELFEXT** + +## I.2 Spectral emulation method (SEM) + +In this method, power sum can then be indirectly measured, not calculated. Figure I.4 shows a 25-pair cable loaded with emulated modem signals at one end and pair #1 has been measured at the other end. + +![Figure I.4: S/N measurement in a loaded cable. The diagram shows a 'Simulator Z' window with a 'Processor Z' connected to 25 modems. A 'Telephone cable 25 pairs' is shown with 'pair #1' being measured. The measurement results include a BER of 0E+0, an S/N [dB] for pair #1 of 48,0, and four waveforms: TX voltage (V), TX [dBm/Hz], RX voltage (V), and RX [dBm/Hz]. The TX waveforms show a signal starting around 100,0k Hz, while the RX waveforms show a signal starting around 10,0k Hz. The cable parameters are Length [km] = 1,0, Gauge [mm] = 0,4, Step [mm] = 25, and Impedance = 100.](b05a8a3551db31147979064952179990_img.jpg) + +The figure displays a simulation interface for a 25-pair telephone cable. On the left, 25 modems are connected to a 'Processor Z'. The modems are labeled 'Modem 1' through 'Modem 25'. A 'Telephone cable 25 pairs' is shown in the center. 'pair #1' is selected for measurement at the far end. The measurement results are shown on the right: BER is 0E+0, S/N [dB] - pair #1 is 48,0. Below the S/N meter, there are four waveforms: TX voltage (V) ranging from -0,1 to 0,2; TX [dBm/Hz] ranging from -600,0 to 0,0; RX voltage (V) ranging from -14,8m to 19,8m; and RX [dBm/Hz] ranging from -300,0 to 0,0. The X-axis for all waveforms is frequency in Hz, ranging from 1,0k to 10,0M. The cable parameters are Length [km] = 1,0, Gauge [mm] = 0,4, Step [mm] = 25, and Impedance = 100. + +Figure I.4: S/N measurement in a loaded cable. The diagram shows a 'Simulator Z' window with a 'Processor Z' connected to 25 modems. A 'Telephone cable 25 pairs' is shown with 'pair #1' being measured. The measurement results include a BER of 0E+0, an S/N [dB] for pair #1 of 48,0, and four waveforms: TX voltage (V), TX [dBm/Hz], RX voltage (V), and RX [dBm/Hz]. The TX waveforms show a signal starting around 100,0k Hz, while the RX waveforms show a signal starting around 10,0k Hz. The cable parameters are Length [km] = 1,0, Gauge [mm] = 0,4, Step [mm] = 25, and Impedance = 100. + +L.75(08)\_FI.4 + +Figure I.4 – S/N measurement in a loaded cable + +Additionally, when data rates for the upstream and downstream directions are measured, the effect of all cable parameters (insertion and return losses, impedance mismatch, unbalance, crosstalk, etc.) combined together will be reflected in the obtained results. + +Figure I.5-a is a copy of a signal used to load one pair measured in the time and frequency domain (envelope). Figure I.5-b shows another signal with more detail: a zoom in over the time domain signal and no average on the frequency domain representation. + +![Screenshot of LabVIEW nScope EX Windowing.vi showing Time and Frequency Domain plots for an averaged ADSL signal. The Time Domain plot shows a periodic waveform over a 100,465u second interval. The Frequency Domain plot shows the power spectral density from 0 to 3,400,000 Hz. The signal strength S is 7,56 dBm.](7c1f9e78e0f033d391b687f1652f6e47_img.jpg) + +The figure shows a LabVIEW interface titled "niScope EX Windowing.vi". It contains two main plots: + +- Time Domain:** A green waveform plot showing a periodic signal over a time interval from 90,918u to 100,465u seconds. The vertical axis ranges from -5,0 to 5,0. +- Frequency Domain:** A yellow power spectral density plot showing the signal's frequency components from 0,000 to 3,400,000 Hz. The vertical axis ranges from -80,0 to 0,0 dBm. + +Below the plots, there are control panels: + +- Grava:** Contains settings for "samples" (65536), "max value" (1), and "min value" (-1,01107). It also has a "Spectro" section with "Par #03". +- Média:** Contains a "Lig./Deslig." checkbox (unchecked) and a "Reiniciar" button. +- Timing Parameters:** Shows "Min. Sample Rate" set to 20,00M and "Min. Record Length" set to 65536. +- S [dBm]:** A gauge showing a signal strength of 7,56 dBm. + +The bottom status bar indicates the window is "niScope EX Windowin..." and "Emulador Espectral". + +Screenshot of LabVIEW nScope EX Windowing.vi showing Time and Frequency Domain plots for an averaged ADSL signal. The Time Domain plot shows a periodic waveform over a 100,465u second interval. The Frequency Domain plot shows the power spectral density from 0 to 3,400,000 Hz. The signal strength S is 7,56 dBm. + +a) ADSL signal in time and frequency domain (averaged) + +![Screenshot of LabVIEW nScope EX Windowing.vi showing Time and Frequency Domain plots for a signal. The Time Domain plot shows a noisy waveform over a 100,0u second interval. The Frequency Domain plot shows the power spectral density from 10,0k to 2,2M Hz. The signal strength S is 10,5 dBm.](c2b98986bdf45e15707f6b2bd7ade2bd_img.jpg) + +The figure shows a LabVIEW interface titled "niScope EX Windowing.vi". It contains two main plots: + +- Time Domain:** A green waveform plot showing a noisy signal over a time interval from 0,0 to 100,0u seconds. The vertical axis ranges from -2,7 to 3,9. +- Frequency Domain:** A yellow power spectral density plot showing the signal's frequency components from 10,0k to 2,2M Hz. The vertical axis ranges from -50,0 to 0,0 dBm. + +Below the plots, there are control panels: + +- Média:** Contains a checked "Lig./Deslig." checkbox and a "Reiniciar" button. +- Timing Parameters:** Shows "Min. Sample Rate" set to 10,00M and "Min. Record Length" set to 5000. +- S [dBm]:** A gauge showing a signal strength of 10,5 dBm. + +The bottom status bar indicates the window is "niScope EX Windowin..." and "Emulador Espectral". + +Screenshot of LabVIEW nScope EX Windowing.vi showing Time and Frequency Domain plots for a signal. The Time Domain plot shows a noisy waveform over a 100,0u second interval. The Frequency Domain plot shows the power spectral density from 10,0k to 2,2M Hz. The signal strength S is 10,5 dBm. + +b) + +**Figure I.5 – Signal in time and frequency domain** + +Figure I.6 shows the downstream data rate (kbit/s) as a function of the number of transmitting disturbing pairs, obtained on a broadband access network using ADSL2plus technology. + +![Line graph titled 'Down Stream Data Rate pair# 2226' showing the downstream data rate (kbit/s) on the y-axis (ranging from 18,400 to 20,600) versus the number of transmitting disturbing pairs on the x-axis (ranging from 0 to 30). The data rate starts at approximately 20,400 kbit/s at 0 pairs, fluctuates between 19,600 and 20,400 kbit/s until about 24 pairs, and then drops sharply to approximately 18,700 kbit/s at 25 pairs.](eaae122ace5c0d761133c6ce971a6ffd_img.jpg) + +| Number of disturbing pairs | Down Stream Data Rate (kbit/s) | +|----------------------------|--------------------------------| +| 0 | 20,400 | +| 5 | 20,000 | +| 10 | 19,600 | +| 15 | 19,700 | +| 20 | 19,600 | +| 24 | 19,500 | +| 25 | 18,700 | + +Line graph titled 'Down Stream Data Rate pair# 2226' showing the downstream data rate (kbit/s) on the y-axis (ranging from 18,400 to 20,600) versus the number of transmitting disturbing pairs on the x-axis (ranging from 0 to 30). The data rate starts at approximately 20,400 kbit/s at 0 pairs, fluctuates between 19,600 and 20,400 kbit/s until about 24 pairs, and then drops sharply to approximately 18,700 kbit/s at 25 pairs. + +**Figure I.6 – Downstream transmission rate** + +Notice the importance of measuring the cable loaded. The data rate varied from 20.4 Mbit/s when the pair was the only one transmitting, to 18.7 Mbit/s when all 25 pairs were loaded and interfering mutually. + +## **I.3 Two methods comparison** + +With the cable loaded direct data rate measurement method for a 100-pair cable group, 99 pairs are fed with non-coherent modem signals, whilst one is taken for upstream and downstream measurement. This process is repeated 100 times until all pairs have been measured. + +The comparison is: 2 000 000 measurements to determine just the PSELFEXT against 100 for upstream plus 100 for downstream. + +The basic difference consists in the way the cable is fed. Usually, for IL, NEXT and ELFEXT, network analysers with two ports are used, one port set as a frequency generator and the other as a power meter. + +On the other hand, with the cable loaded direct data rate measurement method, all pairs of a group, but the one been measured, are loaded at the same time with signals from independent "generators". These independent signals consist of frequency tones, appropriately spaced, modulated, and covering the bandwidth of the DSL technique used. + +Due to the fact that the number of measurements is 10 000 smaller when compared to the conventional power sum evaluation, the time test is drastically reduced, allowing cable manufacturers to test the whole production for quality assurance purposes and allowing telecommunication carriers to assess the performance of their broadband access networks. + +## I.4 Method validation + +The validation process was carried out comparing results obtained with the proposed method, using spectral emulators and real DSLAM-modem connections for different types of cable, length and DSL modulation schemes. + +Figure I.7 shows one of these comparisons made on an installed 3 km cable using ADSL2. + +![Line graph comparing Modem and Emulator results for bit rate vs. disturbing pairs.](cbc4516eb885829fe8c9dabc0946dcbe_img.jpg) + +The graph shows the bit rate in [bit/s] on the y-axis (ranging from 0 to 5,000,000) against the number of disturbing pairs on the x-axis (ranging from 1 to 22). Two data series are plotted: 'Modem' (blue line with diamond markers) and 'Emulator' (magenta line with square markers). Both series start at approximately 3,500,000 bit/s for 1 and 2 disturbing pairs. At 3 disturbing pairs, the bit rate drops sharply to about 2,600,000 bit/s. From 4 to 22 disturbing pairs, the bit rate remains relatively stable, fluctuating between 2,000,000 and 2,200,000 bit/s. The two lines are nearly perfectly overlaid, showing excellent agreement between the modem and emulator results. + +| Disturbing pairs | Modem [bit/s] | Emulator [bit/s] | +|------------------|---------------|------------------| +| 1 | 3,500,000 | 3,500,000 | +| 2 | 3,500,000 | 3,500,000 | +| 3 | 2,600,000 | 2,600,000 | +| 4 | 2,550,000 | 2,550,000 | +| 5 | 2,200,000 | 2,200,000 | +| 6 | 2,150,000 | 2,150,000 | +| 7 | 2,100,000 | 2,100,000 | +| 8 | 2,150,000 | 2,150,000 | +| 9 | 2,150,000 | 2,150,000 | +| 10 | 2,150,000 | 2,150,000 | +| 11 | 2,150,000 | 2,150,000 | +| 12 | 2,100,000 | 2,100,000 | +| 13 | 2,050,000 | 2,050,000 | +| 14 | 2,050,000 | 2,050,000 | +| 15 | 2,050,000 | 2,050,000 | +| 16 | 2,000,000 | 2,000,000 | +| 17 | 2,000,000 | 2,000,000 | +| 18 | 2,000,000 | 2,000,000 | +| 19 | 2,000,000 | 2,000,000 | +| 20 | 2,050,000 | 2,050,000 | +| 21 | 2,050,000 | 2,050,000 | +| 22 | 2,000,000 | 2,000,000 | + +Line graph comparing Modem and Emulator results for bit rate vs. disturbing pairs. + +L.75(08)\_FI.7 + +**Figure I.7 – Methods comparison** + +As can be seen, real results can be predicted precisely and they are indeed valuable for telecommunication carriers. + +# Appendix II + +## Brazilian experience + +(This appendix does not form an integral part of this Recommendation) + +### Introduction + +The spectral emulation method (SEM) has been used for cable and access network test and acceptance purposes by one of the Brazilian long-distance and local carriers. Top-of-the-line equipment, modern xDSL cables and accessories are used in every new broadband network constructed to implement a modern access network in Brazil. + +## II.1 Network architecture + +The photograph in Figure II.1 shows one area where the broadband network installation is been carried out in the city of Rio de Janeiro. + +![Aerial photograph of Rio de Janeiro showing the Jardim Botânico area with network installation routes.](f7bc9b0327ed4589a3faf9a7b3c92712_img.jpg) + +An aerial photograph of a portion of Rio de Janeiro, Brazil. The central focus is a large, irregularly shaped lake, likely Lagoa Botânica, surrounded by urban development and green areas. To the left of the lake is a large, oval-shaped area with a distinct pattern, possibly a race track or a large park. The surrounding city is densely built. Overlaid on the photograph are several colored lines: red lines follow major roads and pathways, while yellow lines form a more complex network, likely representing the fiber optic installation routes. A yellow label "JARDIM BOTANICO" is visible in the upper right quadrant of the image. + +Aerial photograph of Rio de Janeiro showing the Jardim Botânico area with network installation routes. + +**Figure II.1 – Initial installation area in Rio de Janeiro** + +These networks consist of optical rings feeding remote access units (URA), in a fibre-to-the cabinet (FTTC) architecture (Figure II.2). + +![Figure II.2 – FTTC architecture diagram showing a central switching unit connected to two fiber optic loops. The left loop contains URA 1, URA 2, and URA 3. The right loop contains URA 4, URA 5, and URA 6.](76b0cd79baaedd942af4dc42f2e764b8_img.jpg) + +Figure II.2 – FTTC architecture diagram showing a central switching unit connected to two fiber optic loops. The left loop contains URA 1, URA 2, and URA 3. The right loop contains URA 4, URA 5, and URA 6. + +Figure II.2 – FTTC architecture + +The URAs are assembled with mini-DSLAMs connected to high performance xDSL cables. These cables of 50 to 1200 pairs end up at the terminal boxes (TAR) or at the high density connecting frames (CDG). Client modems are then connected using special xDSL wires (Figure II.3). + +![Figure II.3 – Broadband access network diagram. A URA (green rectangle) is connected via xDSL-40-400 cables to three yellow circles. These circles are connected to three orange rectangles labeled TAR, TAR, and CDG. Each of these rectangles is connected to a purple rectangle labeled 'Modems'. A horizontal double-headed arrow at the top indicates a distance of 700 meters from the URA to the modems. The cables between the yellow circles and the TAR/CDG units are labeled xDSL-40-50 to 1200 pairs.](4356776ca004ecba5d599667a155d7d4_img.jpg) + +Figure II.3 – Broadband access network diagram. A URA (green rectangle) is connected via xDSL-40-400 cables to three yellow circles. These circles are connected to three orange rectangles labeled TAR, TAR, and CDG. Each of these rectangles is connected to a purple rectangle labeled 'Modems'. A horizontal double-headed arrow at the top indicates a distance of 700 meters from the URA to the modems. The cables between the yellow circles and the TAR/CDG units are labeled xDSL-40-50 to 1200 pairs. + +Figure II.3 – Broadband access network + +Figures II.4-II.8 show the URA and the TAR. + +![A large grey metal cabinet, labeled 'TELEMAR', sitting on a wooden pallet on a cobblestone street. The cabinet has several doors and is positioned in front of a building with yellow and white walls.](3267a096e9ca525744d8cd820f12eb59_img.jpg) + +A large grey metal cabinet, labeled 'TELEMAR', sitting on a wooden pallet on a cobblestone street. The cabinet has several doors and is positioned in front of a building with yellow and white walls. + +**Figure II.4 – Remote access unit (URA)** + +![An open view of the interior of the remote access unit (URA). The cabinet is filled with numerous modular components arranged in vertical racks. Labels are overlaid on the image: 'INPUT' and 'OUTPUT' on the left side, and 'ADSL' and 'OUTPUT' on the right side.](1630bfd9ebf9b95faec11ae6cdfd9c0a_img.jpg) + +An open view of the interior of the remote access unit (URA). The cabinet is filled with numerous modular components arranged in vertical racks. Labels are overlaid on the image: 'INPUT' and 'OUTPUT' on the left side, and 'ADSL' and 'OUTPUT' on the right side. + +**Figure II.5 – Inside the remote access unit (URA)** + +![A photograph showing a close-up of several vertical rows of metal connecting terminals. Multiple wires, mostly orange and brown, are connected to these terminals. The terminals are arranged in a grid-like pattern within a metal frame.](cd91fd97c6e4da454b42f4fde13f7e44_img.jpg) + +A photograph showing a close-up of several vertical rows of metal connecting terminals. Multiple wires, mostly orange and brown, are connected to these terminals. The terminals are arranged in a grid-like pattern within a metal frame. + +**Figure II.6 – Connecting terminals** + +![A photograph showing a close-up of several black protection modules. These modules are connected to a complex network of wires, including orange, brown, green, and white ones. The modules are mounted on a metal frame, and some are connected to white terminal blocks.](eea8b24476b46def99046ef43c716b10_img.jpg) + +A photograph showing a close-up of several black protection modules. These modules are connected to a complex network of wires, including orange, brown, green, and white ones. The modules are mounted on a metal frame, and some are connected to white terminal blocks. + +**Figure II.7 – Protection modules** + +![A photograph of a white terminal box (TAR) mounted on a concrete pole using black brackets. The background shows green foliage and a wire fence.](793eb94053441c45bcf1e1fad773a7eb_img.jpg) + +A photograph of a white terminal box (TAR) mounted on a concrete pole using black brackets. The background shows green foliage and a wire fence. + +**Figure II.8 – Terminal box (TAR)** + +## **II.2 Test and acceptance procedure** + +To assess high quality service, it is necessary to test all cables (upstream and downstream) at the near and far-end prior to installation. + +After installation, the whole access network must be measured again (downstream only) to ensure that every pair of the system meets the requirements. + +Figure II.9 shows the downstream data rate as a function of the number of interfering pairs, obtained on a broadband access network using ADSL2plus technology. + +![A line graph titled 'Down Stream Data Rate pair# 2226'. The y-axis represents the data rate in bits per second, ranging from 18,400 to 20,600 in increments of 200. The x-axis represents the number of interfering pairs, ranging from 0 to 30 in increments of 5. The blue line shows a fluctuating downward trend, starting at approximately 20,400 bps at 0 pairs and ending at approximately 18,650 bps at 25 pairs.](bd4617f25d15430eb78c2d6d75a99dde_img.jpg) + +| Number of Interfering Pairs | Down Stream Data Rate (bps) | +|-----------------------------|-----------------------------| +| 0 | 20,400 | +| 5 | 20,000 | +| 10 | 19,600 | +| 15 | 19,700 | +| 20 | 19,500 | +| 25 | 18,650 | + +A line graph titled 'Down Stream Data Rate pair# 2226'. The y-axis represents the data rate in bits per second, ranging from 18,400 to 20,600 in increments of 200. The x-axis represents the number of interfering pairs, ranging from 0 to 30 in increments of 5. The blue line shows a fluctuating downward trend, starting at approximately 20,400 bps at 0 pairs and ending at approximately 18,650 bps at 25 pairs. + +**Figure II.9 – Downstream transmission rate** + +## Bibliography + +- [b-ITU-T G.117] Recommendation ITU-T G.117 (1996), *Transmission aspects of unbalance about earth.* +- [b-ITU-T G.961] Recommendation ITU-T G.961 (1993), *Digital transmission system on metallic local lines for ISDN basic rate access.* +- [b-ITU-T G.991.1] Recommendation ITU-T G.991.1 (1998), *High bit rate digital subscriber line (HDSL) transceivers.* +- [b-ITU-T G.991.2] Recommendation ITU-T G.991.2 (2003), *Single-pair high-speed digital subscriber line (SHDSL) transceivers.* +- [b-ITU-T G.992.1] Recommendation ITU-T G.992.1 (1999), *Asymmetric digital subscriber line (ADSL) transceivers.* +- [b-ITU-T G.992.2] Recommendation ITU-T G.992.2 (1999), *Splitterless asymmetric digital subscriber line (ADSL) transceivers.* +- [b-ITU-T G.992.3] Recommendation ITU-T G.992.3 (2005), *Asymmetric digital subscriber line transceivers 2 (ADSL2).* +- [b-ITU-T G.992.4] Recommendation ITU-T G.992.4 (2002), *Splitterless asymmetric digital subscriber line transceivers 2 (splitterless ADSL2).* +- [b-ITU-T G.993.1] Recommendation ITU-T G.993.1 (2004), *Very high speed digital subscriber line transceivers (VDSL).* +- [b-ITU-T G.994.1] Recommendation ITU-T G.994.1 (2003), *Handshake procedures for digital subscriber line (DSL) transceivers.* +- [b-ITU-T G.995.1] Recommendation ITU-T G.995.1 (2001), *Overview of digital subscriber line (DSL) Recommendations.* +- [b-ITU-T G.996.1] Recommendation ITU-T G.996.1 (2001), *Test procedures for digital subscriber line (DSL) transceivers.* +- [b-ITU-T G.997.1] Recommendation ITU-T G.997.1 (2006), *Physical layer management for digital subscriber line (DSL) transceivers.* +- [b-ITU-T G.9954] Recommendation ITU-T G.9954 (2005), *Phoneline networking transceivers – Enhanced physical, media access, and link layer specifications.* +- [b-ITU-T I.361] Recommendation ITU-T I.361 (1999), *B-ISDN ATM layer specification.* +- [b-ITU-T I.432.1] Recommendation ITU-T I.432.1 (1999), *B-ISDN user-network interface – Physical layer specification: General characteristics.* +- [b-ITU-T O.9] Recommendation ITU-T O.9 (1999), *Measuring arrangements to assess the degree of unbalance about earth.* +- [b-ITU-T T.35] Recommendation ITU-T T.35 (2000), *Procedure for the allocation of ITU-T defined codes for non-standard facilities.* +- [b-D 4566-98] American Society for Testing and Materials D 4566-98, *Standard Test Methods for Electrical Performance Properties of Insulations and Jackets for Telecommunications Wire and Cable.* + +- [b-IEC 62255] IEC 62255-series (2003), *Multicore and symmetrical pair/quad cables for broadband digital communications (high bit rate digital access telecommunication networks) – Outside plant cables.* +<> +- [b-ISO 8601:2000] ISO 8601:2000, *Data elements and interchange formats – Information interchange – Representation of dates and times.* +<[http://www.iso.org/iso/iso\\_catalogue/catalogue\\_tc/catalogue\\_detail.htm?csnumber=26780](http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=26780)> + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of 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b/marked/L/T-REC-L.82-201007-I_PDF-E/raw.md @@ -0,0 +1,454 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.82** + +(07/2010) + +SERIES L: CONSTRUCTION, INSTALLATION AND +PROTECTION OF CABLES AND OTHER ELEMENTS OF +OUTSIDE PLANT + +--- + +**Optical cabling shared with multiple operators +in buildings** + +Recommendation ITU-T L.82 + + + +# Recommendation ITU-T L.82 + +## Optical cabling shared with multiple operators in buildings + +## Summary + +At this time, very high broadband network, especially FTTH (fibre to the home) deployment, is a major challenge for operators. One of the main issues is the terminal part of the network with the introduction of optical fibre cables into building up to the apartment with technical difficulties but also administrative ones. Recommendation ITU-T L.82 deals with the solutions which could be deployed to try to answer to building owners, operators and customers' needs. + +This Recommendation refers to the single mode optical cabling in new and existing buildings. Clauses 5 and 6 explain the main constraints of a common optical infrastructure for several operators, offering FTTH services to customers in the same building. Then, the remainder of this Recommendation describes possible cabling solutions which could be deployed in buildings. + +## History + +| Edition | Recommendation | Approval | Study Group | +|---------|----------------|------------|-------------| +| 1.0 | ITU-T L.82 | 2010-07-29 | 15 | + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2011 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +| | Page | +|---------------------------------------------------------------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 2 | +| 3 Terms and definitions ..... | 2 | +| 3.1 Terms defined elsewhere ..... | 2 | +| 3.2 Terms defined in this Recommendation..... | 2 | +| 4 Abbreviations..... | 3 | +| 5 Shared building cabling ..... | 3 | +| 5.1 Single fibre architecture (one fibre for each customer, shared among different operators) ..... | 3 | +| 5.2 Multi-fibres architecture (more than one fibre for each customer, dedicated to single operators or shared among them) ..... | 3 | +| 6 Sharing point..... | 4 | +| 7 Vertical cabling and drop..... | 5 | +| 7.1 Riser cable ..... | 5 | +| 7.2 Drop cable ..... | 5 | +| 7.3 Distribution point..... | 6 | +| 8 Optical termination ..... | 8 | +| 8.1 Customer outlet ..... | 8 | +| 8.2 Optical external network testing interface..... | 9 | +| 9 Optical budget and return loss ..... | 9 | +| 10 Fibres ..... | 9 | +| 11 Connectors ..... | 9 | +| Appendix I – Answers to the questionnaire "Optical cabling shared with multiple operators in buildings" ..... | 11 | +| Bibliography..... | 13 | + +## **Introduction** + +The proposed building cabling allows access to each operator to optical fibres in the building. The main goal of the concept is to be able to share the optical building cabling among different optical access providers. + +The objectives are, on one hand, to reduce fibre installation and maintenance costs in the building (both at the customer premises and in the common parts) and, on the other hand, to reduce disturbance (noise, infrastructure works, dust, etc.) for inhabitants. The goal is also to avoid the possibility for an operator to somewhat "pre-empt" the optical link up to the customer in a building or to avoid cabling duplication if more than one FTTH operator is in a building. + +# Recommendation ITU-T L.82 + +## Optical cabling shared with multiple operators in buildings + +# 1 Scope + +This Recommendation is effective when optical cabling in a building is shared with multiple optical access operators. Figure 1 shows a schematic representation of what could exist in a building with multiple operators' FTTH access networks, without shared cabling. + +![Figure 1: Individual building cabling for each operator. The diagram shows a multi-story building with three separate optical cabling paths (Operator 1 in blue dashed, Operator 2 in red dashed, and Operator 3 in green dashed) entering from the ground and connecting to various units. Each path has 'X' marks indicating multiple connection points or splitters within the building's internal structure. A legend at the bottom left identifies the operators by line style: Operator 1 (blue dashed), Operator 2 (red dashed), and Operator 3 (green dashed). The label 'L.82(10)_F01' is in the bottom right.](49ee89a1d5852ab005dbbab6de09a8a6_img.jpg) + +Figure 1: Individual building cabling for each operator. The diagram shows a multi-story building with three separate optical cabling paths (Operator 1 in blue dashed, Operator 2 in red dashed, and Operator 3 in green dashed) entering from the ground and connecting to various units. Each path has 'X' marks indicating multiple connection points or splitters within the building's internal structure. A legend at the bottom left identifies the operators by line style: Operator 1 (blue dashed), Operator 2 (red dashed), and Operator 3 (green dashed). The label 'L.82(10)\_F01' is in the bottom right. + +**Figure 1 – Individual building cabling for each operator** + +Many cables and boxes could be installed in common parts in this assumption, which can cause permanent disturbance for inhabitants. Besides, saturation of infrastructures could be reached with a strong impact on reliability of existing and new cables and on maintenance issues. + +A challenge for operators in that case could be to try to provide the condition for optical cabling sharing inside the building, as shown in Figure 2: + +![Figure 2: Shared optical building cabling for all operators. The diagram shows the same building but with a shared internal cabling infrastructure. Three external cables (Operator 1 in blue dashed, Operator 2 in red dashed, and Operator 3 in green dashed) enter the building and connect to a common internal vertical riser. From this riser, individual connections are made to the units. Labels 'Operator 1's internal wiring', 'Operator 2's internal wiring', and 'Operator 3's internal wiring' point to the respective internal paths. A legend at the bottom left identifies the operators by line style: Operator 1 (blue dashed), Operator 2 (red dashed), and Operator 3 (green dashed). The label 'L.82(10)_F02' is in the bottom right.](9791722d75115ddcc599b07d7bc35d73_img.jpg) + +Figure 2: Shared optical building cabling for all operators. The diagram shows the same building but with a shared internal cabling infrastructure. Three external cables (Operator 1 in blue dashed, Operator 2 in red dashed, and Operator 3 in green dashed) enter the building and connect to a common internal vertical riser. From this riser, individual connections are made to the units. Labels 'Operator 1's internal wiring', 'Operator 2's internal wiring', and 'Operator 3's internal wiring' point to the respective internal paths. A legend at the bottom left identifies the operators by line style: Operator 1 (blue dashed), Operator 2 (red dashed), and Operator 3 (green dashed). The label 'L.82(10)\_F02' is in the bottom right. + +**Figure 2 – Shared optical building cabling for all operators +(when multiple "optical access networks" are deployed)** + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T G.652] Recommendation ITU-T G.652 (2009), *Characteristics of a single-mode optical fibre and cable.* +- [ITU-T G.657] Recommendation ITU-T G.657 (2009), *Characteristics of a bending loss-insensitive single-mode optical fibre and cable for the access network.* +- [ITU-T L.12] Recommendation ITU-T L.12 (2008), *Optical fibre splices.* +- [ITU-T L.36] Recommendation ITU-T L.36 (2008), *Single-mode fibre optic connectors.* +- [ITU-T L.59] Recommendation ITU-T L.59 (2008), *Optical fibre cables for indoor applications.* +- [ITU-T L.87] Recommendation ITU-T L.87 (2010), *Optical fibre cables for drop applications.* + +# 3 Terms and definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following term defined elsewhere: + +#### 3.1.1 single element [b-IEC 61756-1] + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 building optical line:** Optical line between the sharing point at the building basement and the customer outlet. + +**3.2.2 building operator:** Operator who installs and is responsible for the maintenance of the vertical and/or horizontal cabling in the building and gives an access to it to the other operators. + +**3.2.3 customer outlet:** Allows the connection of fibre(s) from a cable to the ONT. + +**3.2.4 distribution point:** When it exists, the distribution point is the point where customers are connected to the vertical part of the building cabling with an individual cable (the drop cable) by splice and/or connector. The customer could be also connected extracting fibres from the riser cable and routing them to the customer premises. + +**3.2.5 dedicated fibre:** Fibre dedicated for only one operator, which is available permanently for this operator. + +**3.2.6 drop cable:** Individual cable which links up the distribution point or the sharing point to the customer outlet or the optical external network testing interface. This cable can be composed of one or more fibres. + +**3.2.7 optical external network testing interface:** Physical point at which a subscriber is provided with access to an optical communications network. + +**3.2.8 shared fibre:** Fibre shared between several operators, which is available temporarily for one operator. + +**3.2.9 sharing point:** Interface between optical access networks of different operators and the optical building cabling. + +**3.2.10 vertical cabling:** Part of the building cabling between the sharing point and the distribution point when it exists. + +## **4 Abbreviations** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|------------------------------------| +| CO | Customer Outlet | +| ENTI | External Network Testing Interface | +| FTTH | Fibre To The Home | +| ONT | Optical Network Termination | + +## **5 Shared building cabling** + +The building operator or the building owner may take the initiative in cabling a building. They should expect to give access to operators to the optical building lines with a sharing point at the building basement. The number of operators should be limited by a maximum, for practical deployment reasons and based on the real needs of the market. + +The "building operator" deploying the building optical cabling could be in charge of the installation and/or maintenance of this sharing point. + +The shared building cabling combined with the sharing point should support both point-to-point and point-to-multipoint access network topologies. So, a point-to-point network should be used by all the operators between the building basement and customer outlets or the external network testing interfaces. + +### **5.1 Single fibre architecture (one fibre for each customer, shared among different operators)** + +Choice could be made to deploy only one fibre per customer in the vertical part of the building and to share it between the different operators. This choice could be made by the building operator or by the owner of the building, depending on free room in the vertical shaft. + +Operators could have access to shared fibres at the sharing point. Fibres are temporarily assigned to one operator, when needed, to give access to services for customers. + +The single fibre dedicated to the customer could be contained in a single drop cable or in a multi-fibres riser cable (see clause 7). + +### **5.2 Multi-fibres architecture (more than one fibre for each customer, dedicated to single operators or shared among them)** + +Choice could be also made to deploy a multi-fibres architecture based on the installation of minimum 2 fibres per apartment, in which a fibre is dedicated to each operator. + +Operators could have access to dedicated fibres at the sharing point, which are permanently available for their own use. + +It could be also possible to give access to shared fibres with this architecture. + +## 6 Sharing point + +The sharing point is the interface between optical access networks of different operators and the optical building cabling. It should be compatible with point-to-point or point-to-multipoint optical access network architectures. + +Depending on building area and network topologies, the sharing point could be used for one building when the building size is sufficient, but could also be shared between several buildings. It could be installed inside or outside buildings. Information about the localization, number of apartments connected, owner and type of sharing point should be available for all operators. + +It represents: + +- a flexibility point where we can manage the allocation of customers' fibres between operators; +- a demarcation point to separate the responsibility of each operator; +- a point for optical measurements (mainly attenuation and return loss). + +The sharing point should be composed of three parts (Figure 3): + +- a "customer's area" for the management of fibres from riser cables or drop cables (customer module); +- "operator's areas" dedicated for each operator for the management of fibres coming from their access network. These separated areas could be sort of modules with connectors or splice trays, for example. They should be able to accept potential splitters. When it is not possible, splitters could be installed in another box; +- a "connection area" for the interconnection between fibres of the building cabling and access networks with use of patchcords or pigtails. + +![Diagram illustrating the components of a sharing point. It shows a vertical stack of four boxes labeled 'Operator's areas' on the left, connected by dashed lines to a central 'Connection area'. Below the connection area is a box labeled 'Customer's area'. Arrows point to 'Operator's access cables' entering from the bottom left, 'Riser or drop cables' entering from the top right, and the 'Connection area' label.](c2fc2621e8206d24427b56bcb2398fc0_img.jpg) + +The diagram shows a vertical stack of four boxes on the left labeled "Operator's areas". Below these is a box labeled "Customer's area". To the right of the operator's areas is a vertical column labeled "Connection area". Dashed lines connect the operator's areas to the connection area. An arrow from the bottom left points to the operator's areas with the label "Operator's access cables". An arrow from the top right points to the connection area with the label "Riser or drop cables". + +Diagram illustrating the components of a sharing point. It shows a vertical stack of four boxes labeled 'Operator's areas' on the left, connected by dashed lines to a central 'Connection area'. Below the connection area is a box labeled 'Customer's area'. Arrows point to 'Operator's access cables' entering from the bottom left, 'Riser or drop cables' entering from the top right, and the 'Connection area' label. + +L.82(10)\_F03 + +**Figure 3 – Illustration of a sharing point** + +In case of a single fibre sharing architecture, the sharing point should allow an "any to any" cross-connection between shared fibres of the building cabling and fibres from the access networks of each operator. + +When a multi-fibres architecture is deployed in the building, the sharing point should allow, for each operator which has a dedicated fibre in the building, the connection of its own building cabling fibres with fibres from its access network. The sharing point could give both access to dedicated fibres and shared fibres in case of some operators wanting to share their fibres. + +The sharing point should be designed to allow: + +- frequent arrangements of fibres; +- new cable installation or older cable replacement; +- add-on or replacement of optical splitters when splitters are considered inside the sharing point (for PON access networks); +- splicing operations (fusion or mechanical). + +The customer's area should be dimensioned for all customers at day one. It could be useful to have the possibility to install operator's areas only when needed with a modular solution. + +The sharing point should respect environmental standards (climatic, mechanical, dust, etc.) to allow indoor and outdoor settings. + +## 7 Vertical cabling and drop + +Based on operators' consensus, different cabling systems could be installed in the vertical and drop parts: easy mid span access cables, microcabling solutions, preconnectorized solutions, etc. Cables used inside the building should be compliant with [ITU-T L.59]. They have to be fire retardant low smoke no halogen. + +Figure 4 shows examples of cabling solutions in a building, both applicable to the single fibre or multi-fibres architecture. + +![Figure 4: Two diagrams of a building showing cabling solutions. The left diagram shows a riser cable running vertically through the building, with drop cables branching off to each floor. The right diagram shows a drop cable running vertically, with connections to each floor. Both diagrams include labels for 'Distribution point', 'Drop cable', 'Riser cable', 'Customer outlet or optical network testing interface', 'Operators', and 'Sharing point'. The right diagram is labeled 'L.82(10)_F04'.](8e14350b4b669119a3bdfca7869110ca_img.jpg) + +The diagram illustrates two architectural approaches for vertical cabling in a multi-story building. In the left approach, a central 'Riser cable' runs vertically, connecting a 'Sharing point' at the base to a 'Distribution point' on an upper floor. 'Drop cables' then branch out from the distribution point to individual 'Customer outlet or optical network testing interface' units on each floor. In the right approach, the 'Drop cable' itself runs vertically from the 'Sharing point' at the base to the customer outlets on each floor, with a 'Distribution point' located on one of the floors. Both diagrams show the 'Operators' area at the base and the 'Sharing point' location. + +Figure 4: Two diagrams of a building showing cabling solutions. The left diagram shows a riser cable running vertically through the building, with drop cables branching off to each floor. The right diagram shows a drop cable running vertically, with connections to each floor. Both diagrams include labels for 'Distribution point', 'Drop cable', 'Riser cable', 'Customer outlet or optical network testing interface', 'Operators', and 'Sharing point'. The right diagram is labeled 'L.82(10)\_F04'. + +**Figure 4 – Example of cabling solutions in buildings: both the riser cable or the drop cable could contain one or more fibres for each customer depending on the chosen architecture** + +### 7.1 Riser cable + +The riser cable(s) should be dimensioned to connect all customers in the building. + +Depending on the building configuration (number of apartments, floors, etc.), type of sharing architecture (single fibre or multi-fibres), a riser cable could be based on single elements of one or several fibres (4, 8 or 12 fibres for example) to serve distribution points. + +In order to reduce the time for installation of the cable extremity in the sharing point, it could be pre-terminated with connector plugs. + +### 7.2 Drop cable + +Drop cables should be compliant with [ITU-T L.87]. + +Only one single drop cable could be used for each customer. It can contain one single mode fibre (case of a single fibre sharing architecture) or several single mode fibres (multi-fibres architecture). + +Depending on building architectures, drop cables could be laid (see Figure 3): + +- from the sharing point to the external network testing interface or the customer outlet; +- from the distribution point to the external network testing interface or the customer outlet. + +Dimensional and mechanical characteristics of the cable must be adapted for different building configurations. The drop cable can be pulled in existing sleeves but also stuck or stapled along the walls, or installed in a conduit. Techniques of blown cables/fibres in microducts can also be used. + +Installation of the drop cable could be made at day one (for example, in case of new buildings), or only on-demand when a customer asks for the service (existing buildings). + +The drop cable could be pre-terminated with connector plugs, at only one end or at both ends. This would significantly reduce the cost and skill-set required for installation of the drop cable. It could also be interesting for quality reasons. On the other hand, the use of pre-terminated solutions at both ends involves that a number of given lengths of the drop cable have to be chosen in order to cover the possible path lengths in the building. Moreover, the management of the over-length of cable is needed. + +### **7.3 Distribution point** + +The link between riser cable(s) and drop cables could be located at the distribution point. + +Fibres of the vertical cable are connected to fibres of drop cables by splices or/and connectors, or directly routed to the customer premises. In the first case, the distribution point could be made by a distribution box or a distribution system. In the second case, it could be made by only a breakout box. + +#### **7.3.1 Distribution box** + +The distribution boxes should be designed to allow splices and/or connectors (with pre-connectorized solutions or field mountable connectors for instance). They should allow the management of fibres. + +The distribution boxes are installed in the vertical part of the building at floor levels. Their location depends on the distribution boxes capacity, cables modularity, number of floors and customers per floor, installation facilities (existence or not of a vertical shaft, width and depth of the vertical shaft). A distribution box can serve several floors. + +For riser cables with single elements dedicated to a single customer, small distribution boxes dedicated for only one customer can be used. These boxes should be only installed when laying the drop cable instead of at initial time when laying the riser cable. + +#### **7.3.2 Breakout box** + +A breakout box could be used to break out and distribute the single elements from the riser cable into small protective tubes without the need of any splice. With the term "element", one fibre or a group of fibres is indicated. The protected single elements can be routed directly from the riser cable to the customer premises or to an intermediate point with splice. + +#### **7.3.3 Distribution system** + +A distribution system could be used when there is not enough free space in the vertical shaft, or it is not possible to obtain the permission to install "at sight" a distribution box at floor level. + +The distribution system could include: + +- breakout boxes and small tubes to extract and protect the single elements; +- protection accessories which allow to protect the splice between the fibres from the riser cable and the fibres from the drop cable with a miniaturized solution. + +Both the breakout box and the splice(s) protection accessory could be physically separated and located in different points at floor level (as an example, the breakout box is necessarily located in the vertical shaft on the riser cable, but the splice protection accessory could be located inside the tube to the customer flat). An example of a distribution system is shown in Figure 5. + +![Diagram of a distribution system showing a riser cable in a vertical shaft, a breakout box at floor level, a splice protection accessory, and tubes leading to customer outlets.](ff0952ef692c9d960ce5f6708bcc9711_img.jpg) + +The diagram illustrates a distribution system for optical fibers. A vertical dashed red line represents the 'Riser cable' running through a 'Vertical shaft'. At a floor level, indicated by a horizontal dashed line, a 'Breakout box and small tubes for the protection of the extracted fibres at floor' (shown in blue) is connected to the riser cable. From this box, two green lines representing 'Drop cable (1 fibre module)' extend horizontally. A 'Splice protection accessory' (indicated in red) is located on one of these drop cables. The drop cables then enter a 'Tube to the customer flat', represented by a dashed line. Each tube terminates at a 'Customer outlet' (shown in grey). A legend at the bottom identifies the dashed red line as the 'Riser cable' and the dashed black line as the 'Drop cable (1 fibre module)'. + +Diagram of a distribution system showing a riser cable in a vertical shaft, a breakout box at floor level, a splice protection accessory, and tubes leading to customer outlets. + +L.83(10)\_F05 + +**Figure 5 – Example of a distribution system** + +When the distribution system is dedicated for only one customer, the installation of the distribution system could be made partially at initial time, installing the breakout box, but the splice protection accessory could be installed only when the customer is connected with the drop cable. + +Several customers could be served by one single tube over several meters from the riser cable to an additional derivation point, and then have their own tube entering the flat: an example is shown in Figure 6, in which at this derivation point the connection among the protective small tubes is made by using an appropriate accessory. + +![Figure 6: Example of a distribution system and derivation accessory in the case of initial sharing of customer tube. The diagram shows a vertical shaft with a riser cable (dashed red line) and a drop cable (solid green line). A breakout box and small tubes for the protection of the extracted fibres at floor are shown. The drop cable branches into a 'Tube to more than one customer flat' and a 'Tube to the customer flat'. A derivation accessory is shown on the drop cable, leading to a customer outlet. A splice protection accessory is also shown on the drop cable, leading to another customer outlet. A legend at the bottom indicates: Drop cable (1 fibre module) and Riser cable.](4801720824e4b5e2361a5564f91cfb70_img.jpg) + +Figure 6: Example of a distribution system and derivation accessory in the case of initial sharing of customer tube. The diagram shows a vertical shaft with a riser cable (dashed red line) and a drop cable (solid green line). A breakout box and small tubes for the protection of the extracted fibres at floor are shown. The drop cable branches into a 'Tube to more than one customer flat' and a 'Tube to the customer flat'. A derivation accessory is shown on the drop cable, leading to a customer outlet. A splice protection accessory is also shown on the drop cable, leading to another customer outlet. A legend at the bottom indicates: Drop cable (1 fibre module) and Riser cable. + +L.83(10)\_F06 + +**Figure 6 – Example of a distribution system and derivation accessory in the case of initial sharing of customer tube** + +## 8 Optical termination + +The connection of a drop cable (or a single element extracted from the riser cable) fibre with the optical network termination at the customer premises could be accomplished through a customer outlet and/or an optical external network testing interface. Figure 7 illustrates typical configurations. + +![Figure 7: Illustration of typical cabling configurations at the customer premises. The diagram shows three configurations within an 'Apartment' containing a 'Distribution space'. 1. A drop cable connects directly to a CO (Customer Outlet), which is connected to an ONT (Optical Network Termination). 2. A drop cable connects to an ENTI (External Network Testing Interface), which is connected to a Cable, which is connected to a CO, which is connected to an ONT. 3. A drop cable connects to an ENTI, which is connected to an ONT. The diagram is labeled L.82(10)_F07.](a26e142d3df5bef41a84a9dd099d7825_img.jpg) + +Figure 7: Illustration of typical cabling configurations at the customer premises. The diagram shows three configurations within an 'Apartment' containing a 'Distribution space'. 1. A drop cable connects directly to a CO (Customer Outlet), which is connected to an ONT (Optical Network Termination). 2. A drop cable connects to an ENTI (External Network Testing Interface), which is connected to a Cable, which is connected to a CO, which is connected to an ONT. 3. A drop cable connects to an ENTI, which is connected to an ONT. The diagram is labeled L.82(10)\_F07. + +**Figure 7 – Illustration of typical cabling configurations at the customer premises** + +### 8.1 Customer outlet + +The customer outlet allows the connection of fibre(s) from a cable to the ONT. It is installed inside the apartment at a convenient place regarding the apartment configuration and customer requirements. In the case the distribution space is not present, the customer outlet can represent a demarcation, measuring and testing point. + +The fibre(s) from the cable could be spliced with pigtail(s) or terminated with field mountable connectors when the cable is not already pre-terminated with optical plug(s). A patchcord (fibre optic cable terminated with connectors on both ends) is then used to connect the ONT to the customer outlet. + +### 8.2 Optical external network testing interface + +The optical ENTI is a demarcation, measuring and testing point and allows the isolation of the customer's in-house cabling from the building's cabling. It would be installed at the entrance of the apartment, outside or inside the apartment. When installed inside, it should be in a distribution space (collocated near the home distributor). + +The connection of fibres from the drop cable with the ONT is done the same way as with the optical outlet with connector plugs. It could also be an interface between the drop cable and the customer outlet when the ONT is not located in the distribution space. + +## 9 Optical budget and return loss + +In order to be used by any operator, independently of the transmission technology chosen, the building operator or the building owner should guarantee for the optical lines they provide: + +- a maximum attenuation between the two ends of the line; +- a minimum return loss. + +Considering that the attenuation due to short fibre length is not significant, a theoretical value of the attenuation could be calculated by taking into account the numbers, type of connections (connectors, fusion splices or mechanical splices) and type of fibres connected. It should also be noted that cable bending can also contribute significantly to the total power budget. + +This value could vary a lot according to the building cabling architecture. Attenuation values are defined in [ITU-T L.36] for optical connectors and [ITU-T L.12] for splices. + +## 10 Fibres + +Single mode optical fibres described in [ITU-T G.652] and [ITU-T G.657] should be used for cables (riser cables, drop cables), patchcords and pigtails at the different parts of the building cabling depending upon users' environmental conditions and technical requirements. + +Bending loss insensitive single mode optical fibres [ITU-T G.657] should be preferred, especially for the drop part of the building cabling where fibres should have more bend constraints. It could allow a faster installation, a higher margin for the optical budget and also a possible reduction of boxes size. + +In cases of limited optical budget, care should be taken to use for the whole cabling fibres which are compatible for connection in order to minimize insertion losses for each connection. When ITU-T G.652 and ITU-T G.657 fibres are used at the same time, choice of ITU-T G.657A would be then preferred for bending loss insensitive fibres. + +## 11 Connectors + +Connectors could be used in the sharing point, the customer outlet, the external network testing interface, the distribution box and customer premises equipment with different environmental conditions. They could be manipulated by qualified technicians in the sharing point, for example, but also by the customer at the outlet. They have to be reliable over a long time period, with low insertion losses. + +The SC connector (SC/APC or SC/UPC) is the most commonly used in building cabling by operators who deploy FTTH. LC connector could also be employed to increase the density of materials. + +In order to be compliant with services which require high quality transmission (and therefore low reflection losses), it could be recommended to use angled physical contact (APC) connectors which guarantee 60 dB (mated) or 55 dB (unmated) for return losses [ITU-T L.36]. + +Depending on their location, it could be useful to install connectors and/or adaptors with an integrated dust and laser safety protection. + +Connectors can be mounted on fibres at the factory but also on the field. Main features of field mountable connectors in terms of types, fields of application, configurations and technical aspects should be defined in a future ITU-T Recommendation. + +## Appendix I + +## Answers to the questionnaire "Optical cabling shared with multiple operators in buildings" + +(This appendix does not form an integral part of this Recommendation) + +This appendix presents answers to the questionnaire on "Optical cabling shared with multiple operators in buildings" sent to collect opinions, information and experiences about optical building cabling. Some of the countries which answered the questionnaire already share the optical building cabling but not all. + +| | +|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Is optical building cabling already shared with other operators in your country? | +|

The optical building cabling is already shared with other operators in Estonia, Kyrgyzstan, Republic of Korea, Switzerland, Ukraine.

It is not already shared in Bosnia Herzegovina, Cambodia, Cyprus, Dominican Republic, Japan, Lithuania, Moldavia, Netherlands, Peru, Philippines, Czech republic, Thailand, Turkey, Vietnam

| +| Did your country (national regulation authority) start discussion with operators about shared building cabling? | +|

In Korea, a guideline for certification of very high speed ICT network in building was legislated by the Korea Communications Commission. Shared building cabling method is described in the guideline.

In Turkey, discussion has just started.

In Switzerland, COMCOM and OFCOM have been very active organizing round-table discussions with operators to discuss many aspects of the FTTH roll-out including the in-building cabling. An industry working group under the chairmanship of OFCOM has produced technical guidelines for the in-house installation of FTTH networks. These guidelines ensure that the installation supports sharing by several network operators. The first edition of the guidelines is available. Work is progressing on a second edition. Operators are encouraged to follow it.

In Vietnam, the Ministry of Industry and Communication is drafting the national standards for telecom building cabling system and Telecom infrastructure sharing.

| +| Have you defined the type of optical connector which could be used in Cross-Connecting Point (shared point at the basement of building), Distribution Box (at floors) and optical outlet (or optical ENTI)? | +|

Cyprus: SC/PAC for pilots

Estonia: not defined but preference for SC

Kirgystan: FC and LC

Japon (NTT): SC/PC

Philippines (Globe Telekom): SC

Switzerland: LC/APC for the optical outlet

Turkey (Turk Telecom): SC and LC

Ukraine: FC, LC, SC

Vietnam: FC, LC, SC/PC or SC/UPC

There is sometimes national standardization

| +| Have you defined a maximum optical attenuation/minimum optical return loss between apartment and building basement? | +|

No in general.

In Switzerland, a maximum attenuation is not specified but can be deduced from: basement distribution box + socket 0.8 or 0.9 dB (fusion splice: 0.15, mechanical splice 0.25, LC connector 0.5). RL = 60 dB

| + +| | +|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Have you defined the type of fibre in vertical cabling, especially in the drop and customer patchcord? | +|

BH Telecom in Bosnia Herzegovina: G.657A.

NTT in Japan: G.652 (vertical cabling) and G.657A1 (indoor cables, namely horizontal cabling to each apartment).

KT Corporation in Korea has defined the type of fibre. They have also defined the telecommunication Pipe Shaft to accommodate the fibre.

In Switzerland: G.657A for cables, the fibre of the customer patchcord is not specified.

Turk Telekom in Turkey: G.652D and G.657.

JSC Ukrtelecom in Ukraine: G.652D and G.657A in vertical cabling + G.657A for drop.

Ministry of Communication in Vietnam: G.652 for FTTH homes, small offices, G.657 for building offices depending on customers/project requirements.

| +| Have you defined the need for optical ENTI and/or optical customer outlet implementation inside or outside the apartment? | +|

In Japan, the customer outlet is installed in the apartment to accelerate the "do it yourself" by customers. If there is an ENTI outside (on the wall outside), there is also an optical outlet inside.

In Kyrgystan, they are installed inside.

In Switzerland, there is only an optical outlet inside the apartment (living room, office, wall box).

In Turkey, the optimum point is defined according to apartment cabling.

In Ukraine the ENTI is outside, the customer outlet inside.

In Vietnam, it depends on customers' requirements.

| +| Do you think it is useful to install an optical outlet in apartment (for example in the living room) if optical ENTI is already installed at entrance of apartment? | +|

Cyprus replies it is useful only for new buildings.

NTT (Japan) thinks it is useful to install an optical outlet inside the flat to accelerate "Do It Yourself" by customers.

In Switzerland there is no ENTI, only an optical outlet.

In Turkey there is no need for optical outlet because there is no fibre inside the apartment (copper cat 5/6)

| +| Have you defined where to stop drop installation: outside or inside the apartment? | +|

In most of cases, when it is defined, it is inside the apartment.

Sometimes, it can depend on building owners, existing network provider, new entrant, etc.

| + +## Bibliography + +- [b-IEC 61756-1] IEC 61756-1 (2006), *Fibre optic interconnecting devices and passive components – Interface standard for fibre management systems – Part 1: General and guidance.* + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git 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the International Telecommunication Union (ITU) features a globe with a red lightning bolt striking it, symbolizing telecommunications. The text "ITU" is prominently displayed in blue, with "International Telecommunication Union" written in smaller blue text to the right. + +ITU logo + + + +## Recommendation ITU-T L.84 + +# Fast mapping of underground networks + +## Summary + +Recommendation ITU-T L.84 describes a fast solution for mapping underground networks, necessary to plan the execution of work using trenchless or digging techniques and to optimize the path, thus avoiding the risk of damage to both the existing infrastructures and the drilling equipment. This Recommendation gives advice on general requirements about this solution and the output of utility maps. + +## History + +| Edition | Recommendation | Approval | Study Group | +|---------|----------------|------------|-------------| +| 1.0 | ITU-T L.84 | 2010-07-29 | 15 | + +## Keywords + +CAD, fast solution, GIS, GPR, ground penetrating radar, 3D. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2010 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +| | Page | +|---------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Abbreviations and acronyms ..... | 1 | +| 4 Ground penetrating radar ..... | 1 | +| 5 GPR3D fast investigation ..... | 3 | +| 5.1 Hardware ..... | 3 | +| 5.2 Software..... | 4 | +| 5.3 GPR3D output system ..... | 5 | +| 5.4 Additional features ..... | 5 | +| Appendix I – Italian experience regarding fast solution GPR3D ..... | 7 | +| Bibliography..... | 9 | + +# **Introduction** + +Nowadays, Georadar (GPR – ground penetrating radar) is used for the investigation of the soil before using trenchless techniques, in order to detect some utilities below the ground, like gas or water ducts, that intersect the area where the trench should be dug. But the existing technologies require the post-processing of data, which is time-consuming and requires highly-skilled staff. It is recommended to use the fast solution GPR3D (ground penetrating radar 3 dimensions), in order to reduce time and to be usable by unskilled people. + +## **Recommendation ITU-T L.84** + +# **Fast mapping of underground networks** + +# **1 Scope** + +This Recommendation: + +- gives some application criteria; +- gives advice on the features of GPR3D system for performing the fast investigation of the soil; +- gives advice on how to produce the final map of the investigated area. + +# **2 References** + +None. + +# **3 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|---------------------------------------| +| CAD | Computer-Aided Drafting | +| GIS | Geographical Information Systems | +| GPS | Global Positioning System | +| GPR | Ground Penetrating Radar | +| GPR3D | Ground Penetrating Radar 3 Dimensions | +| NGN | Next Generation Networks | +| Rx | Receiver | +| Tx | Transmitter | + +# **4 Ground penetrating radar** + +A radar can detect discontinuities below ground, in addition to its normal use for locating objects in the air. The equipment used in a GPR system is schematically represented in Figure 1. + +![Figure 1 – GPR logical scheme. The diagram shows a GPR system with a transmitter antenna and a receiver antenna on the ground surface. A control unit is connected to both antennas and to a data storage and data display unit. The transmitter antenna sends a transmitted pulse into the soil. The pulse is reflected by a buried object and also refracted into the bedrock. The reflected energy is received by the receiver antenna. The direct arrival is also received by the receiver antenna. The scattered energy is also received by the receiver antenna. The ground surface is shown, and the soil and bedrock layers are indicated. The diagram is labeled L.84(10)_F01.](3121ebddccf183ca63bb9781be440a7e_img.jpg) + +Figure 1 – GPR logical scheme. The diagram shows a GPR system with a transmitter antenna and a receiver antenna on the ground surface. A control unit is connected to both antennas and to a data storage and data display unit. The transmitter antenna sends a transmitted pulse into the soil. The pulse is reflected by a buried object and also refracted into the bedrock. The reflected energy is received by the receiver antenna. The direct arrival is also received by the receiver antenna. The scattered energy is also received by the receiver antenna. The ground surface is shown, and the soil and bedrock layers are indicated. The diagram is labeled L.84(10)\_F01. + +**Figure 1 – GPR logical scheme** + +An antenna transmits an electromagnetic wave into the ground and the back-scattered radiation is received and then processed, to extract the information relevant to buried objects. Usually any discontinuity of the electromagnetic properties of the soil (dielectric constant and conductivity) is detected. Objects can be classified according to their geometry: planar surfaces, long and thin objects (cables and pipes), local objects. Wideband time-domain impulse radar systems are available commercially and are usually offered with a range of antennae to suit the desired probing range. The extent of ground penetration is limited by the attenuation of the signal: the penetration increases at longer wavelengths, but resolution is higher at shorter wavelengths, so the choice of frequency is usually a compromise between the two. In Table 1, some frequency values are shown with an approximate estimate of the expected penetration in favorable propagation conditions. + +**Table 1 – Frequency vs penetration** + +| Penetration (m) | Frequency (MHz) | +|-----------------|-----------------| +| 0.5 – 1.0 | 1000 | +| 1.0 – 2.0 | 500 | +| 2.0 – 1.0 | 200 | +| 5 – 15 | 100 | +| 10 – 30 | 50 | +| 30 – 50 | 25 | +| 50 – 100 | 10 | + +The investigation depth is also strictly related to the nature of the ground: GPR works best in dry granular soils and may not be able to see far through waterlogged or dense clay. + +Most antennae have relatively small footprints which means that rapid and wide-area surveying can only be achieved with array radar systems. These systems use more than one antenna, mounted on a fixed scheme, which allows the acquisition of a large amount of data in a relatively short time, and so makes easier the final interpretation of the probing results. + +Particularly in urban areas, it is recommended to use an array radar system, to improve the probability of detection of underground utilities and reduce the overall investigation time. + +# 5 GPR3D fast investigation + +From the point of view of the operators, nowadays GPR systems present the following limits: + +- 2D real-time results displayed on the monitor are difficult to understand for people (Figure 2); therefore, it is necessary to make some parallel scansion to eliminate false alarms; +- in order to have 3D results and the information about buried objects, post-processing of the field data is mandatory. + +![Figure 2 – Traditional GPR results. The image shows a 2D GPR radargram with multiple hyperbolic reflections. The vertical axis represents time in nanoseconds (ns), ranging from 0.0 to 8.0. The horizontal axis represents distance in meters (m), ranging from 0.0 to 10.0. The reflections are complex and overlapping, making it difficult to identify specific buried objects without post-processing.](925f55ce69802b9d3b00546382663ee2_img.jpg) + +Figure 2 – Traditional GPR results. The image shows a 2D GPR radargram with multiple hyperbolic reflections. The vertical axis represents time in nanoseconds (ns), ranging from 0.0 to 8.0. The horizontal axis represents distance in meters (m), ranging from 0.0 to 10.0. The reflections are complex and overlapping, making it difficult to identify specific buried objects without post-processing. + +**Figure 2 – Traditional GPR results** + +The fast GPR3D should be realized by an antenna array and should have the following features: + +- it should display in real time the 3D results about buried utilities; +- it should be user friendly so that unskilled people can understand the problems without difficulty; +- it should detect univocally underground services using 3D GPR acquisition; +- it should georeference traces and they should be imported in a GIS system or in a CAD file. + +The main advantage of such a GPR3D fast system shall be the time reduction for the introspection and the improvement of the reliability. + +## 5.1 Hardware + +The GPR3D machine should have particular features in order to support most of the functionalities required in the soil introspection activity. + +First, the trolley of the georadar shall be mainly composed of dielectric material to avoid interference with radio signals used by the machine. + +The georadar shall be equipped with devices, such as a GPS receiver and an odometer, which allow to fix the geographical coordinates. + +The georadar includes a ruggedized laptop connected with antennae and other devices. The laptop running a particular software is the console that allows the operator to control the entire machine. + +It is recommended that the hardware of the georadar support an operative temperature range compliant with the application, and the power supplies support all the activities for at least one whole working day. + +The GPR3D acquisition speed should be as fast as a walking pace. + +The entire introspection activity using the georadar should be performed by a single person, i.e., he or she should guide the machine, check the results on the display and mark with spray on the road the presence of the buried object. + +### **5.1.1 Antenna system** + +It is recommended that the georadar device use an antenna system (rx and tx dipoles) able to detect both transversal and longitudinal buried utilities. + +In order to support fast acquisition, the antenna system shall perform the introspection in one-pass scanning of the area to be investigated. + +The depth of the investigation should be 100 cm at least. For this reason, it is recommended to use a frequency that allows to reach the desired depth and to have a good resolution. + +### **5.1.2 GPS receiver** + +It is recommended that GPR be equipped with a GPS receiver, so that it can georeference all buried objects, i.e., real spatial coordinates (latitude and longitude) are associated to the buried objects, in order to track the path of the investigation. + +### **5.1.3 Odometer** + +It is recommended that: + +- an odometer be used, in order to correct GPS errors; +- the odometer introduces an error less than 1 cm for each metre. + +## **5.2 Software** + +It is recommended that the software perform automatically data elaboration in real-time, avoiding the post-processing phase. + +The man-machine interface should be user friendly, and should allow the operator to examine the results both of longitudinal and transversal buried utilities. + +The operator records georeferenced buried utilities, and it is recommended that he or she adds attributes, such as a text description, environmental images, acquired by a webcam, or audio files, recorded during acquisition. These buried objects are recorded like WayPoints both in GIS output and in CAD. + +The software should record tracks in a georeferenced way. + +### **5.2.1 Migration** + +It is recommended that a migration algorithm be implemented in georadar software, so that data are easily understood by unskilled people (Figure 3), that is unskilled operators in geophysics data analysis. As for seismic data, migration is used to compensate for distortions caused by non-horizontal reflectors and for collapsing diffraction hyperbolas into their apex. Migration algorithms valid for post-stack migration of seismic data may be successfully used to migrate radar data. A good estimate of the material velocity is needed to produce a good result. + +![Figure 3 shows two side-by-side GPR (Ground Penetrating Radar) data displays. The left side shows raw data with multiple hyperbolic reflections. The right side shows the real-time elaboration results, featuring a red horizontal line indicating the trench depth and two yellow markers highlighting specific buried utilities.](d48475a25698b1c0592e4cfe07138f2a_img.jpg) + +Figure 3 shows two side-by-side GPR (Ground Penetrating Radar) data displays. The left side shows raw data with multiple hyperbolic reflections. The right side shows the real-time elaboration results, featuring a red horizontal line indicating the trench depth and two yellow markers highlighting specific buried utilities. + +**Figure 3 – Example of raw data and migration** + +On the left side of Figure 3, there are raw data while on the right side the real-time elaboration results are visible: the red line shows the trench depth and the two yellow bullets represent migrated data related to respectively two buried utilities. + +## **5.3 GPR3D output system** + +One of the main aspects of the soil investigations for the detection of underground utilities is the production of maps that can be easily used by operators performing installation or maintenance work on site. The final report shall provide details of buried utilities. + +The final map, showing the position of the detected utilities, shall be drawn with respect to the same coordinate system adopted in the field, so that it is easy to correlate the map with the local environment. + +The software of GPR3D systems must provide a link with a CAD station and GIS to transfer directly on a digital map the information relevant to the position and depth of the detected underground utilities. + +### **5.3.1 CAD** + +The software shall have the possibilities to create a file compliant with CAD format with all data of the investigation, like WayPoint, Track and attributes. + +When an existing CAD cartography of the investigated area is available, the information relevant to the position of the detected utilities should be integrated with the existing cartography by directly updating it. + +### **5.3.2 GIS** + +The software shall have the possibilities to create a file compliant with GIS system with all data of the investigation, like WayPoint, Track and attributes. + +## **5.4 Additional features** + +The uninterrupted development of urban areas requires a detailed knowledge of the route of buried networks, their hindrance and the soil stratigraphy in order to simplify laying and maintenance works. Before planning a new infrastructure, a series of inspections should be carried out. This is usually done by digging some essays (Figure 4). This kind of invasive inspection causes many inconveniences to traffic, people and public activities. + +![A photograph showing a small, shallow trench dug into a paved surface, likely for testing or localization purposes. The trench is surrounded by a metal frame and a pile of excavated earth. In the background, there is a fence and some greenery.](d5a837fa4f4675e5ee596003cf55985c_img.jpg) + +A photograph showing a small, shallow trench dug into a paved surface, likely for testing or localization purposes. The trench is surrounded by a metal frame and a pile of excavated earth. In the background, there is a fence and some greenery. + +A photograph showing a small, shallow trench dug into a paved surface, likely for testing or localization purposes. The trench is surrounded by a metal frame and a pile of excavated earth. In the background, there is a fence and some greenery. + +**Figure 4 – Digging essay for existing utilities localization** + +### **5.4.1 GPR3D "Digging Essay"** + +In order to avoid troubles for people's safety, the GPR3D system should be used, in order to locate the buried utilities, without dismantling the roadbed. The GPR3D procedure for the location of utilities in a small area should be carried out by acquiring a series of parallel profiles. A series of georadar profiles should be acquired in a row so that they are parallel to each other and at the same distance from each other. + +### **5.4.2 Stratigraphic soil investigation** + +In addition to its use for locating buried utilities, the GPR3D can also detect ground characteristics. Nowadays probing techniques are used, but the GPR3D system can be used in order to understand where it is more convenient to cut and dig, without creating problems to people. The electromagnetic soil backscatter is processed to extract the information relevant to the ground features: water content and granulometry. The ground features can be extracted by analysing the electromagnetic signature of the ground response. + +# Appendix I + +## Italian experience regarding fast solution GPR3D + +(This appendix does not form an integral part of this Recommendation) + +Nowadays, in Italy, the deployment of the NGN has been driven towards the infrastructure laying miniaturization and so towards the use of trenchless techniques. For this reason, mapping of underground network is needed, and so the GPR3D system solution is implemented and other additional features are in progress. + +The first step is to create a system to locate underground facilities, in order to understand where it is possible to cut without problems. The Italian GPR3D system solution is shown in Figure I.1. + +![Figure I.1 shows two photographs of the Italian GPR3D system. The left photo shows a person in an orange safety vest pushing a GPR3D unit along a paved road. The right photo shows the GPR3D unit parked on a sidewalk next to a building, with a laptop mounted on top of it.](eb22a8740f7c6a0f6ee98f16d99ed8b9_img.jpg) + +The image consists of two side-by-side photographs. The left photograph shows a person wearing an orange high-visibility safety vest and holding a flag, standing next to a GPR3D unit on a paved road. The right photograph shows the GPR3D unit parked on a sidewalk, with a laptop mounted on top of it. + +Figure I.1 shows two photographs of the Italian GPR3D system. The left photo shows a person in an orange safety vest pushing a GPR3D unit along a paved road. The right photo shows the GPR3D unit parked on a sidewalk next to a building, with a laptop mounted on top of it. + +**Figure I.1 – Real-time GPR3D Italian system** + +The Italian GPR3D system solution can display in real time the 3D results about buried utilities; it is used for plants of various operators and more than 20 km of investigation have been just made in few months. + +It is possible to import georeferenced data in a GIS system or in a CAD file. Georeferenced traces with all buried objects recorded during the investigation, with information about the distance from the start point and the depth can be seen. For example, after the investigation, the operator can press a GIS button on the interface of the georadar, create the file compliant with the GIS system, and finally he can drag and drop this file into the GIS system maps, thus being able to see all the information recorded during the investigation (Figure I.2). The same operation can be done for the CAD output file (Figure I.3). + +![Aerial photograph showing a blue line representing GPR data with yellow markers labeled START, S1TR(300, 40m_45cm), S2LT(I)(710,00m_50cm), S3LT(F)(1232,50m_30cm), S4TR(3212m_50c), and Saliceto Panaro STOP.](7c1f9e78e0f033d391b687f1652f6e47_img.jpg) + +An aerial photograph of a suburban area with a blue line representing a GPR survey path. The path starts at a point labeled 'START' and ends at 'Saliceto Panaro STOP'. Along the path, there are four yellow pushpin markers with labels: 'S1TR(300, 40m\_45cm)', 'S2LT(I)(710,00m\_50cm)', 'S3LT(F)(1232,50m\_30cm)', and 'S4TR(3212m\_50c)'. The background shows residential buildings, roads, and some green spaces. + +Aerial photograph showing a blue line representing GPR data with yellow markers labeled START, S1TR(300, 40m\_45cm), S2LT(I)(710,00m\_50cm), S3LT(F)(1232,50m\_30cm), S4TR(3212m\_50c), and Saliceto Panaro STOP. + +**Figure I.2 – GPR data imported in GIS system** + +![CAD drawing showing the GPR data path as a red line on a black background with white grid lines and technical drawings.](c2b98986bdf45e15707f6b2bd7ade2bd_img.jpg) + +A CAD drawing on a black background. It features a red line representing the GPR data path, which follows a similar route to the one in Figure I.2. The background includes white line drawings of buildings, roads, and a grid system. The drawing is a technical representation of the survey data within a CAD environment. + +CAD drawing showing the GPR data path as a red line on a black background with white grid lines and technical drawings. + +**Figure I.3 – GPR data imported in CAD file** + +# Bibliography + +- [b-ITU-T L.39] Recommendation ITU-T L.39 (2000), *Investigation of the soil before using trenchless techniques.* +- [b-Cottino] Cottino, E., Di Buono, N. (2009), *A complete enabling solution for FTTx network infrastructure*, IWCS. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.86-201007-I_PDF-E/042733dc5e8e7f5f30b60adba3266cde_img.jpg b/marked/L/T-REC-L.86-201007-I_PDF-E/042733dc5e8e7f5f30b60adba3266cde_img.jpg new file mode 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optical access networks** + +Recommendation ITU-T L.89 + + + +## Recommendation ITU-T L.89 + +# Design of suspension wires, telecommunication poles and guy-lines for optical access networks + +## Summary + +Recommendation ITU-T L.89 describes the general requirements and a design guide for suspension wires, telecommunication poles and guy-lines that support aerial cables for optical access networks. This Recommendation also describes loads applied to the infrastructures. + +## History + +| Edition | Recommendation | Approval | Study Group | +|---------|----------------|------------|-------------| +| 1.0 | ITU-T L.89 | 2012-02-13 | 15 | + +## Keywords + +Aerial infrastructure, guy-line, ice loading, suspension wire, suspension wire tension, telecommunication pole, vertical load, wind loading. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2012 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|------------|--------------------------------------------------------------------------------------|---| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 3.1 | Term defined elsewhere ..... | 1 | +| 3.2 | Terms defined in this Recommendation..... | 1 | +| 4 | Abbreviations and acronyms ..... | 2 | +| 5 | Conventions ..... | 2 | +| 6 | Configuration of aerial infrastructure ..... | 2 | +| 6.1 | Aerial communication infrastructure on shared poles..... | 2 | +| 7 | General requirements for aerial infrastructure design ..... | 2 | +| 7.1 | Clarification of optical fibre cables ..... | 2 | +| 7.2 | Classification of site conditions..... | 2 | +| 7.3 | Safety and economic considerations ..... | 3 | +| 7.4 | Management of ground height and offset distance..... | 3 | +| 7.5 | Loads applied to aerial infrastructure ..... | 3 | +| 8 | Design of suspension wires ..... | 5 | +| 8.1 | Materials ..... | 5 | +| 8.2 | Selection of suspension wire type ..... | 5 | +| 8.3 | Sag ..... | 5 | +| 9 | Design of telecommunication poles ..... | 6 | +| 9.1 | Materials ..... | 6 | +| 9.2 | Embedded depth ..... | 6 | +| 9.3 | Pole length ..... | 6 | +| 9.4 | Classification ..... | 6 | +| 10 | Design of guy-lines..... | 7 | +| 10.1 | Configuration..... | 7 | +| 10.2 | Installation angle of upper guy-lines ..... | 7 | +| 10.3 | Classification of upper guy-lines..... | 7 | +| 10.4 | Classification of guy anchors ..... | 7 | +| Appendix I | – Relationship between sag and the length of suspension wire ..... | 9 | +| I.1 | Introduction ..... | 9 | +| I.2 | Calculation of required suspension wire length ..... | 9 | +| I.3 | Calculation considering the change of temperature and load applied to the wire ..... | 9 | + +## **Introduction** + +Suspension wires, telecommunication poles and guy-lines that support aerial optical fibre cables are important facilities for providing broadband services. An appropriate design is needed to maintain the reliability of these facilities and services. Moreover, they are big facilities installed at a high position, and so they should be managed in a way that ensures sufficient safety. To realize these requirements, a design is needed that carefully considers facility strength. + +# Design of suspension wires, telecommunication poles and guy-lines for optical access networks + +# 1 Scope + +This Recommendation deals mainly with fundamental requirements for designing suspension wires, telecommunication poles and guy-lines supporting aerial optical cables. In this Recommendation aerial infrastructures mean suspension wires, telecommunication poles and guy-lines. The intent of such a plant is to support outdoor cables that will be attached by lashings, clips, or similar mechanisms. + +Note that self-supporting cables such as the one shown in Figure 8, ADSS, or others, while not specifically addressed by this Recommendation, have the same issues applicable to their installation. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T L.26] Recommendation ITU-T L.26 (2002), *Optical fibre cables for aerial application*. + +[ITU-T L.58] Recommendation ITU-T L.58 (2004), *Optical fibre cables: Special needs for access network*. + +[ITU-T L.87] Recommendation ITU-T L.87 (2010), *Optical fibre cables for drop applications*. + +[ITU-T L.88] Recommendation ITU-T L.88 (2010), *Management of poles carrying overhead telecommunication lines*. + +# 3 Definitions + +### 3.1 Term defined elsewhere + +None. + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 guy-line:** A wire installed to prevent poles collapsing as a result of tension imbalances that occur during or after cable installation. One end of the guy-line is fixed to the pole and the other end is fixed to the ground by a guy anchor. + +**3.2.2 messenger:** An alternative term for suspension wire. + +**3.2.3 suspension wire:** Wire that is installed in advance between telecommunication poles from which aerial optical cables are suspended. It supports a tension applying to non-self-supporting aerial optical cables. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +ADSS All-Dielectric Self-Supporting + +CAPEX Capital Expenditure + +# 5 Conventions + +None. + +# 6 Configuration of aerial infrastructure + +The aerial infrastructure consists of a suspension wire (messenger), a telecommunication pole and a guy-line as shown in Figure 1, and supports the optical fibre cables for aerial applications described in [ITU-T L.26], [ITU-T L.58] and [ITU-T L.87]. + +![Diagram of aerial infrastructure showing a suspension wire (messenger) supported by a telecommunication pole and a guy-line.](e1a0d046fbe7f28f5e93a47091851747_img.jpg) + +The diagram illustrates the configuration of aerial infrastructure. It features two vertical telecommunication poles. A horizontal suspension wire (messenger) is strung between the top of the left pole and the top of the right pole. Four circular cross-sections of optical fibre cables are shown suspended from this messenger wire. A guy-line, represented by a blue diagonal line, is anchored to the ground and attached to the right telecommunication pole. The label 'L.89(12)\_F01' is located at the bottom right of the diagram. + +Diagram of aerial infrastructure showing a suspension wire (messenger) supported by a telecommunication pole and a guy-line. + +**Figure 1 – Aerial infrastructure** + +### 6.1 Aerial communication infrastructure on shared poles + +The aerial optical cable infrastructure may also be co-located on poles carrying power cables. While such installations follow the intent of this Recommendation, the effects of the loading, spacing, and guy-line construction for the power cables must also be considered. Local regulations will also affect the spacing and sag of communication plants. + +# 7 General requirements for aerial infrastructure design + +### 7.1 Clarification of optical fibre cables + +The main function of the aerial infrastructure is to support optical fibre cables. The type and number of optical fibre cables that are supported are decided based on demand forecasts and future plans for networks, and so the design of an aerial infrastructure strongly depends on the optical fibre cables supported. Therefore, telecommunication companies shall know what kind of optical fibre cables will be installed; taking account of their future plans. + +### 7.2 Classification of site conditions + +Ideally, aerial infrastructure is designed in accordance with the conditions of each individual site. However, designing on such an individual basis raises capital expenditure (CAPEX). Therefore, a certain level of design standardization is necessary to simplify the design and construction process, in order to reduce CAPEX. As one example of this standardization, site conditions may be classified based on wind loading, ice loading and/or soil property. Telecommunication companies should carefully investigate the site conditions so that the site can be correctly classified. + +### 7.3 Safety and economic considerations + +Aerial infrastructure consists of large facilities that are installed high above the ground. So, it is recommended that telecommunication companies carefully consider safety and avoid any accidental destruction to aerial infrastructure by employing a design with sufficient strength and protection against lightning. Note that telecommunication companies should also consider reducing CAPEX while maintaining safety. + +### 7.4 Management of ground height and offset distance + +It is recommended that aerial infrastructure (including cables shown in [ITU-T L.26], [ITU-T L.58] and [ITU-T L.87]) has sufficient ground height to prevent any component from being a traffic barrier and to eliminate risks to people and other constructions. The ground height shall be evaluated in wind-free conditions. An offset distance that is as great as possible should be established between optical fibre cables and electrical cables to achieve safety and workability. In general, ground height and offset distances are defined by regulations, and so telecommunication companies shall follow these regulations when designing aerial infrastructure. + +![Diagram illustrating the required ground height for aerial infrastructure. Two vertical poles support a cable that sags between them. A horizontal dashed line extends from the lowest point of the cable to the ground. A vertical double-headed arrow indicates the distance from the ground to this lowest point, labeled 'Required ground height'. The diagram is labeled L.89(12)_F02.](a86610f7a0e579fec9f34dea52fa088b_img.jpg) + +Diagram illustrating the required ground height for aerial infrastructure. Two vertical poles support a cable that sags between them. A horizontal dashed line extends from the lowest point of the cable to the ground. A vertical double-headed arrow indicates the distance from the ground to this lowest point, labeled 'Required ground height'. The diagram is labeled L.89(12)\_F02. + +**Figure 2 – Ground height** + +### 7.5 Loads applied to aerial infrastructure + +Aerial infrastructure should be designed in accordance with the loads applied to them to maintain their reliability and safety. In particular, telecommunication companies should carefully consider wind loading, suspension wire tension and vertical load, as shown in Figure 3. These loads must include the weight of the cable(s) which are expected to be supported by the suspension wire (see clause 7.1). + +#### 7.5.1 Wind loading + +The wind load peaks when the wind blows at right angles to an aerial infrastructure. At that time, the wind load $T_w$ [N] can be obtained by the following equation. + +$$T_w = \frac{1}{2} \rho C_D V_w^2 S \quad (7-1)$$ + +where $\rho$ , $C_D$ , $V_w$ and $S$ are the air density, the drag coefficient of the infrastructure determined by wind tunnel testing, the wind velocity and the profile area of the cable and the suspension wire, respectively. Note that ice accretion to the cable and suspension wire may increase in their profile area. + +#### 7.5.2 Suspension wire tension + +The suspension wire tension is the load supported by suspension wire. The suspension wire tension $T$ [N] can be obtained with the following equation. + +$$T = \frac{WL^2}{8d} \quad (7-2)$$ + +where $L$ is a span length. $d$ is a sag and has an inverse ratio to $T$ . In terms of the ground height, a smaller sag is desirable, but this increases suspension wire tension as shown in Figure 4, and so an aerial infrastructure with greater mechanical strength is required. Therefore, telecommunication companies should design the sag and the suspension wire tension so that they are in balance. As shown in Figure 5, $W$ is the load imposed by the sum of the wind load and the cable weight. Note that the resultant load $W$ [N/m] should be defined as the value per unit length. So, it is given by: + +$$W = \sqrt{w^2 + \left(\frac{T_w}{D}\right)^2} \quad (7-3)$$ + +where $w$ and $D$ are an aggregate of cable and suspension wire weights per unit length and aggregate of cable and wire diameters, respectively. Note that the suspension wire tension reaches its maximum value at its minimum temperature because metal contracts as the temperature falls. Ice loading should be included in cable weight. Ice loading guidelines are generally established by local, regional, or national authorities. Different ice density values for radial and rime ice may be used depending upon local conditions. + +#### 7.5.3 Vertical load + +This is load applied to a telecommunication pole vertically. Typical vertical loads are as follows: + +- weight of telecommunication pole; +- weight of snow and ice adhering to telecommunication pole; +- vertical component of guy-line tension; +- weight of workers and tools. + +It is recommended for telecommunication companies to consider maximum vertical load when designing telecommunication poles. + +![Diagram of a telecommunication pole showing wind load, suspension wire tension, and vertical load.](b0211cee4b20034939d883ac0d70f696_img.jpg) + +The diagram illustrates a telecommunication pole with a horizontal crossarm. Red arrows represent wind load, shown as horizontal arrows pointing towards the pole from the left and as diagonal arrows pointing downwards and to the right along the pole's height. A horizontal red arrow pointing left from the right side of the crossarm represents suspension wire tension. A vertical red arrow pointing downwards from the center of the crossarm represents the vertical load. A guy wire is shown on the right side, extending from the pole to the ground. The diagram is labeled 'L.89(12)\_F03' at the bottom right. + +Diagram of a telecommunication pole showing wind load, suspension wire tension, and vertical load. + +Figure 3 – Wind load, suspension wire tension and vertical load + +![Figure 4: Relationship between suspension wire tension and sag. The diagram shows two identical suspension wire setups between two vertical poles. Each setup consists of a wire suspended between the poles, forming a catenary curve. The horizontal distance between the poles is labeled 'L'. The vertical distance from the horizontal line connecting the poles to the lowest point of the wire is labeled 'd' (sag). The tension at the poles is labeled 'T'. The right diagram is labeled 'L.89(12)_F04'.](967c30813761a8952ecc5e16bf42ea45_img.jpg) + +Figure 4: Relationship between suspension wire tension and sag. The diagram shows two identical suspension wire setups between two vertical poles. Each setup consists of a wire suspended between the poles, forming a catenary curve. The horizontal distance between the poles is labeled 'L'. The vertical distance from the horizontal line connecting the poles to the lowest point of the wire is labeled 'd' (sag). The tension at the poles is labeled 'T'. The right diagram is labeled 'L.89(12)\_F04'. + +**Figure 4 – Relationship between suspension wire tension and sag** + +![Figure 5: Resultant load applied to a suspension wire. The diagram shows a cylindrical wire segment. An arrow labeled 'Wind' points towards the wire. A vector labeled 'T_w/D' points vertically downwards from the center of the wire. Another vector labeled 'w' points vertically downwards from the center of the wire. The resultant vector, labeled 'W: Resultant load', is shown as the vector sum of 'T_w/D' and 'w'. The diagram is labeled 'L.89(12)_F05'.](6d9013c24741e861f3c8e0a763b6da22_img.jpg) + +Figure 5: Resultant load applied to a suspension wire. The diagram shows a cylindrical wire segment. An arrow labeled 'Wind' points towards the wire. A vector labeled 'T\_w/D' points vertically downwards from the center of the wire. Another vector labeled 'w' points vertically downwards from the center of the wire. The resultant vector, labeled 'W: Resultant load', is shown as the vector sum of 'T\_w/D' and 'w'. The diagram is labeled 'L.89(12)\_F05'. + +**Figure 5 – Resultant load applied to a suspension wire** + +# 8 Design of suspension wires + +### 8.1 Materials + +It is recommended that stranded steel wire be used as suspension wire. Anticorrosive material, e.g., aluminium-coated steel or zinc-coated steel, should be used for the suspension wire in areas with a corrosion risk. Typical corrosion risk areas are as follows: + +- Near the coast; corrosion by salt breeze. +- Industrial and mining areas; corrosion by sulphur dioxide gas. +- Hot springs (warm water found in a volcanic location) and volcanic areas; corrosion by hydrogen sulphide. + +### 8.2 Selection of suspension wire type + +It is recommended for telecommunication companies to select the suspension wire in accordance with the specifications of the aerial cables that it supports. When a future expansion plan for optical cables becomes clear, telecommunication companies may employ the suspension wire that conforms to their plan in advance. The applicable type of suspension wire should be decided carefully based on its tensile strength, calculated suspension wire tension and safety margin. + +### 8.3 Sag + +The sag of a suspension wire reaches its maximum value at the maximum temperature or under the maximum weather loading. So, it is recommended for telecommunication companies to carefully consider the temperature conditions at the installation site. + +## 9 Design of telecommunication poles + +### 9.1 Materials + +Telecommunication poles should be made of steel, reinforced concrete or wood. + +### 9.2 Embedded depth + +The embedded depth of the pole shall be decided in accordance with the subsurface condition of the ground and the material of the pole to prevent poles from collapsing. A greater embedded depth shall be employed for soft ground such as a paddy field area, an embanked zone and peat soil. The use of a pole anchor is also effective for coping with such ground conditions. The method for evaluating a telecommunication pole's foundation is described in [ITU-T L.88]. + +![Diagram illustrating two examples of pole anchors. The left example shows a pole with two horizontal anchor plates embedded in the ground. The right example shows a pole with a single horizontal anchor plate at the base. The ground is represented by a light orange shaded area.](e159e9f78612406820a4d40e26e01413_img.jpg) + +L.89(12)\_F06 + +Diagram illustrating two examples of pole anchors. The left example shows a pole with two horizontal anchor plates embedded in the ground. The right example shows a pole with a single horizontal anchor plate at the base. The ground is represented by a light orange shaded area. + +**Figure 6 – Example of pole anchor** + +### 9.3 Pole length + +The pole length is limited by the ground height defined by regulations. So, the pole length should be designed to satisfy the required ground height whenever the sag (temperature) reaches its maximum value. At that time, the embedded depth and the surplus length should also be considered. + +### 9.4 Classification + +Telecommunication poles are typically classified based on their purpose as follows (Figure 7): + +- intermediate pole; +- corner pole; +- terminal pole. + +The intermediate pole is located midway in the rectilinear cable region. The intermediate pole is affected by wind loads acting on it, wires and cables. So, guy-lines should be installed on both sides of the intermediate pole. The installation interval of the guy-line should be decided in accordance with the wind load at the site. It is recommended that two side guy-lines be installed every two poles as long as the site condition permits it when the wind load is classified at the highest level. + +A corner pole is installed at a bent section of an aerial optical cable line. This corner pole is affected by the resultant load of angular bidirectional suspension wire tensions. So, it is recommended that a guy-line be installed on one side. Note that there is no need to use a guy-line when the suspension wire tension is sufficiently small. + +The terminal pole is located at the start and end points of cable lines, and is affected by unbalanced suspension wire tension. So, it is recommended that a terminal guy-line be installed. Note that there is no need to use a guy-line when the suspension wire tension is sufficiently small. + +## 10 Design of guy-lines + +### 10.1 Configuration + +A guy-line consists of an upper and a lower part. The upper part of the guy-line (i.e., upper guy-line) is attached to telecommunication poles. The lower part of the guy-line (i.e., guy anchor) is buried to exploit the bearing capacity of the soil. + +### 10.2 Installation angle of upper guy-lines + +The installation angle, which is formed by the pole and the upper guy-lines, may be more than 25 degrees. + +### 10.3 Classification of upper guy-lines + +Upper guy-lines are typically classified based on their purpose as follows (Figure 7): + +- terminal guy-line; +- one side guy-line; +- two side guy-line. + +Terminal guy-lines are attached to terminal poles, and should be installed parallel to optical cables. If the allowable strength of the single guy-line is insufficient, two guy-lines can be used. One side guy-lines are attached to the corner poles. One side guy-lines should be installed in the direction bisecting the corner angle. Two side guy-lines are mainly attached to the intermediate poles. Two side guy-lines should be installed every two poles when the wind load is classified at the highest level. + +### 10.4 Classification of guy anchors + +Guy anchors are typically classified according to their purpose as follows (Figure 8): + +- piton anchor; +- block anchor; +- spiky bolt anchor. + +The piton anchor, which is a spiky steel piton driven into the ground, is used in most cases except when the installation is on rock or when the driving action might damage existing underground installations or facilities. When it cannot be used, the next choice is the block anchor. The guy-line is held in place by an anchor block formed on site by pouring concrete into a hole, which is then refilled and compacted. However, this also cannot be installed on rock. For an installation on rock, a shallow hole is drilled and a spiky bolt is inserted and mortared in place. + +![Figure 7: Classification of telecommunication pole and upper guy-line. The diagram shows two examples of pole configurations. The left example shows a 'Corner pole' with a 'One side guy' attached at an angle bisecting the corner, and an 'Intermediate pole' with 'Two side guy' lines attached. The right example shows a 'Terminal pole' with a 'Terminal guy' line attached. A label 'L.89(12)_F07' is present at the bottom right of the diagram.](f20786b603b41e24b5d5899f710b5947_img.jpg) + +The diagram illustrates two common telecommunication pole configurations. On the left, a 'Corner pole' is shown with a 'One side guy' line attached at an angle that bisects the corner formed by the incoming and outgoing lines. Further along the line is an 'Intermediate pole' with 'Two side guy' lines attached at angles. On the right, a 'Terminal pole' is shown at the end of a line, with a 'Terminal guy' line attached. A label 'L.89(12)\_F07' is located at the bottom right of the diagram. + +Figure 7: Classification of telecommunication pole and upper guy-line. The diagram shows two examples of pole configurations. The left example shows a 'Corner pole' with a 'One side guy' attached at an angle bisecting the corner, and an 'Intermediate pole' with 'Two side guy' lines attached. The right example shows a 'Terminal pole' with a 'Terminal guy' line attached. A label 'L.89(12)\_F07' is present at the bottom right of the diagram. + +Figure 7 – Classification of telecommunication pole and upper guy-line + +![Diagram showing three types of guy anchors: Piton anchor, Block anchor, and Spiky bolt anchor in Mortar. A vertical pole is shown on the left with dashed lines pointing to each anchor type.](0dd5ee731e9d7e34e498b5c926110773_img.jpg) + +A diagram illustrating three types of guy anchors for a vertical pole. The pole is shown on the left. Three dashed lines originate from the pole and point to different anchor types: 1. Piton anchor: A red, curved metal spike driven into the ground. 2. Block anchor: A red, rectangular block placed on the ground. 3. Spiky bolt anchor: A red bolt with a circular head and a spiky base, set into a rectangular patch of mortar (indicated by diagonal hatching) on the ground. The ground is represented by a horizontal orange band. + +Diagram showing three types of guy anchors: Piton anchor, Block anchor, and Spiky bolt anchor in Mortar. A vertical pole is shown on the left with dashed lines pointing to each anchor type. + +**Figure 8 – Classification of guy anchors** + +L.89(12)\_F08 + +## Appendix I + +## Relationship between sag and the length of suspension wire + +(This appendix does not form an integral part of this Recommendation.) + +### I.1 Introduction + +It is useful to calculate the suspension wire length to meet the requirement of the sag which is decided according to the required ground height. Here, a basic formula for the calculation of the required suspension wire length is introduced. + +### I.2 Calculation of required suspension wire length + +A shape of a suspension wire supported by poles is the catenary curve. Therefore, the length of suspension wire can be calculated based on a well-known arc length of the catenary curve. The length of suspension wire supported by poles $l$ [m] is expressed as follows. + +$$l = L + \frac{L^3 W^2}{24 T^2} \quad (\text{I-1})$$ + +where $L$ [m], $T$ [N] and $W$ [N/m] are a span length, the suspension wire tension and the load imposed by the sum of the wind load and the cable weight, respectively. The following formula is given by substituting equation (7-2) for $T$ in equation (I-1). + +$$l = L + \frac{8d^2}{3L} \quad (\text{I-2})$$ + +Moreover, Young's module $E$ [N/m2] is defined as follows. + +$$E = \frac{\frac{T}{A}}{\frac{l - l_0}{l_0}} \quad (\text{I-3})$$ + +where $l_0$ [m] is the length of suspension wire before supporting a load, i.e., the wire length which should be prepared before its construction. $A$ [m2] is the cross-section area of the wire. Finally, $l_0$ is calculated by substituting equation (I-2) for $l$ in equation (I-3) and solving for $l_0$ . + +$$l_0 = L \left\{ 1 + \frac{8}{3} \left( \frac{d}{L} \right)^2 \right\} \left( \frac{EA}{EA + T} \right) \quad (\text{I-4})$$ + +Equation (I-4) immediately provides the required suspension wire length for arbitrary sag and span length. + +### I.3 Calculation considering the change of temperature and load applied to the wire + +The environment where wires and cables are installed is not stable. In particular, the temperature and the load are momentarily changed. So, with regard to their design, it is significant to consider any changes. + +Here, the situation in which the temperature and the load are changed from $\theta$ to $\theta_1$ [°C] and from $W$ to $W_1$ , respectively, is considered. Note that the change of the load is mainly caused by changes in wind pressure. The parameters used for the calculation are as follows. + +$L$ [m]: span length + +$l_0$ [m]: length of suspension wire before supporting a load at temperature of $\theta$ + +$l_0'$ [m]: length of suspension wire before supporting a load at temperature of $\theta_1$ + +$l$ [m]: length of suspension wire supported by poles at temperature of $\theta$ and load of $W$ + +$d$ [m]: sag at temperature of $\theta$ and load of $W$ + +$T$ [N]: suspension wire tension at temperature of $\theta$ and load of $W$ + +$l_1$ [m]: length of suspension wire supported by poles at temperature of $\theta_1$ and load of $W_1$ + +$d_1$ [m]: sag at temperature of $\theta_1$ and load of $W_1$ + +$T_1$ [N]: suspension wire tension at temperature of $\theta_1$ and load of $W_1$ + +$\alpha$ [°C]: linear expansion coefficient of the wire + +$E$ [N/m2]: Young's module of the wire + +$A$ [m2]: cross-section area of the wire + +When changing the temperature from $\theta$ to $\theta_1$ , the length of the suspension wire before supporting $l_0'$ is expressed as, + +$$l_0' = l_0 \{1 + \alpha(\theta_1 - \theta)\} \quad (I-5)$$ + +So, when the wire is supported by poles, the length of the wire supported by poles $l_1$ is given by: + +$$l_1 = l_0 \{1 + \alpha(\theta_1 - \theta)\} \left(1 + \frac{T_1}{EA}\right) \quad (I-6)$$ + +Here, by substituting equation (I-2) for $l$ in equation (I-6), $l_0$ is expressed as follows. + +$$l_0 = \frac{L \left\{1 + \frac{8}{3} \left(\frac{d_1}{L}\right)^2\right\}}{\{1 + \alpha(\theta_1 - \theta)\} \left(1 + \frac{T_1}{EA}\right)} \quad (I-7)$$ + +Regarding equation (I-4) and equation (I-7), + +$$L \left\{1 + \frac{8}{3} \left(\frac{d}{L}\right)^2\right\} \{1 + \alpha(\theta_1 - \theta)\} \left(1 + \frac{T_1}{EA}\right) = L \left\{1 + \frac{8}{3} \left(\frac{d_1}{L}\right)^2\right\} \left(1 + \frac{T_1}{EA}\right) \quad (I-8)$$ + +When substituting equation (7-2) into equation (I-8) and by neglecting some smaller terms, the following relation is given. + +$$T_1^3 + EA \left\{ \alpha(\theta_1 - \theta) + \frac{1}{24} \left(\frac{WL}{T}\right)^2 - \frac{T}{EA} \right\} T_1^2 = \frac{1}{24} (W_1 L)^2 EA \quad (I-9)$$ + +This is the formula to calculate the suspension wire tension $T_1$ when the temperature and the load change from $\theta$ to $\theta_1$ and from $W$ to $W_1$ . Of course, the sag at this condition can also be immediately calculated by using equation (7-2). + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/L/T-REC-L.9-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg b/marked/L/T-REC-L.9-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg 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a/marked/L/T-REC-L.94-201501-I_PDF-E/raw.md b/marked/L/T-REC-L.94-201501-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..7462a508e55292f81c070f8b5773f3e480f81e61 --- /dev/null +++ b/marked/L/T-REC-L.94-201501-I_PDF-E/raw.md @@ -0,0 +1,307 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**L.94** + +(01/2015) + +SERIES L: CONSTRUCTION, INSTALLATION AND +PROTECTION OF CABLES AND OTHER ELEMENTS OF +OUTSIDE PLANT + +--- + +**Use of global navigation satellite systems to +create a referenced network map** + +Recommendation ITU-T L.94 + + + +# Recommendation ITU-T L.94 + +## Use of global navigation satellite systems to create a referenced network map + +## Summary + +Recommendation ITU-T L.94 provides general implementation guidelines regarding the creation, operation and maintenance of the telecommunication network map by using the global navigation satellite system (GNSS) and geo-referenced systems. This Recommendation deals with potential information on outdoor infrastructures to be collected, the procedure for creating a geo-referenced map and the operation and maintenance of geo-referenced systems when the network infrastructure is updated. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T L.94 | 2015-01-13 | 15 | 11.1002/1000/12414 | + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2015 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 1 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 2 | +| 6 Telecommunication outdoor infrastructure in a geo-referenced map..... | 2 | +| 6.1 Information ..... | 2 | +| 6.2 Elements of the network..... | 2 | +| 7 Software..... | 2 | +| 8 Mobile device used in the field..... | 3 | +| 9 Global positioning system ..... | 3 | +| 10 Maintenance of digital existing data..... | 3 | +| 11 Procedure ..... | 3 | +| 12 Local and remote database..... | 4 | +| Appendix I – Italian experience regarding geo-referencing system ..... | 5 | + + + +# Recommendation ITU-T L.94 + +## Use of global navigation satellite systems to create a referenced network map + +## 1 Scope + +The purpose of this Recommendation is to provide general implementation guidelines regarding the creation, operation, and maintenance of the telecommunication network map by using global navigation satellite system (GNSS) and geo-referenced systems. This Recommendation deals with potential information on outdoor infrastructures to be collected, the procedure for creating a geo-referenced map, and the operation and maintenance of geo-referenced systems when the network infrastructure is updated. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T L.64] Recommendation ITU-T L.64 (2012), *ID tag requirements for infrastructure and network elements management*. + +[ITU-T L.69] Recommendation ITU-T L.69 (2007), *Personal digital assistant requirements and relevant data structure for infrastructure and network elements management*. + +[ITU-T L.90] Recommendation ITU-T L.90 (2012), *Optical access network topologies for broadband services*. + +## 3 Definitions + +### 3.1 Terms defined elsewhere + +None. + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 differential global navigation satellite system (DGNSS):** Navigation system that derives differential location information by comparing traditional global navigation satellite system (GNSS)-based data to localized reference positions. It is a technology that provides better location accuracy than traditional GNSS, from 5-10 metres down to a few metres depending on the availability of line of sight satellite communications, to about 10 cm in case of the best implementations. + +**3.2.2 geo-referencing:** The process of applying a coordinate system to a layer of data, in order to define its existence in physical space. + +**3.2.3 global navigation satellite system (GNSS):** A system of satellites that provide autonomous geo-spatial positioning with global coverage. The global navigation satellite system (GNSS) receiver calculates its own position on earth. This positional information can be used in many applications such as mapping, surveying, navigation and mobile geographical information system (GIS). + +**3.2.4 WGS-84:** The World Geodetic System – 1984 (WGS-84) coordinate system is a conventional terrestrial system (CTS), realized by modifying the Navy navigation satellite system (NNSS), Doppler Reference Frame (NSWC 9Z-2) in origin and scale, and rotating it to bring its reference meridian into coincidence with the International Time Bureau – defined zero meridian. + +## **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|--------|-------------------------------------------------| +| CAD | Computer Aided Design | +| DGNSS | Differential Global Navigation Satellite System | +| GIS | Geographical Information System | +| GNSS | Global Navigation Satellite System | +| ID | Identification | +| PDA | Personal Digital Assistant | +| WGS-84 | World Geodetic System – 1984 | + +## **5 Conventions** + +None. + +## **6 Telecommunication outdoor infrastructure in a geo-referenced map** + +A geo-referenced map should be in digital format. + +### **6.1 Information** + +The information of telecommunication outdoor infrastructure in a geo-referenced map depends on user requirements. Typical examples of information in telecommunication network geo-referenced maps are as follows: + +- the cable routing and the type of infrastructure; +- the length of each section; +- the owner of each section; +- the status of infrastructure use, for example empty or occupied duct; +- the year of installation; +- the number of ducts; +- the dimensions of the duct, cable, optical closure and optical cabinet, etc.; +- the number and the type of cable inside the duct; +- distribution points (as described in [ITU-T L.90]). + +### **6.2 Elements of the network** + +On the geo-referenced map, the following minimum network element should be visualized: central offices, poles, manholes, optical closures, optical cabinets, ducts and tunnels. + +## **7 Software** + +Network maps should be visualized both in geographical information system (GIS) format for geographical view, and in a computer aided design (CAD) system, for schematic view. + +## **8 Mobile device used in the field** + +The device used for collecting in-field data should be a mobile handheld device, compliant with [ITU-T L.69]. It is suggested that the mobile device has a screen with sufficient dimensions to see the map. + +## **9 Global positioning system** + +In order to geo-reference the network elements, assign geographical coordinates, elevation, longitude and latitude, it is recommended to use a global navigation satellite system (GNSS) receiver. + +However, a GNSS has a positioning accuracy of 5 to 10 metres, because there must be a relative line of sight between the GNSS antenna and at least four satellites. Objects, such as buildings, overpasses, and other obstructions, that shield the antenna from a satellite can potentially weaken a satellite's signal such that it becomes too difficult to ensure reliable positioning. These difficulties are particularly prevalent in urban areas. In order to have reliable positioning both in urban and in non-urban areas, with an error from 1 to 10 cm, it is recommended to use differential GNSS. + +## **10 Maintenance of digital existing data** + +A geo-referenced map should show the users the position, the name and the status of the network element (such as new, old or to be changed) and additional information. Furthermore, a geo-referenced map should show the process of maintenance of the infrastructure components, scheduling times for periodic maintenance and the status of the maintenance action through a work flow system. + +The status of the network elements should be upgraded when finishing a construction or repairing work and the mean time of update should depend on the network element type. + +## **11 Procedure** + +The procedures for creating digital and geo-referenced cartography are different depending on whether or not the paper network maps exist. + +If network maps exist in paper format, digital map should be created through CAD editing and it should be possible to import it in GIS. + +If network maps of a specific zone do not exist, digital maps should be created through various steps. It is recommended to execute the following process at least: + +- The survey process: People should collect data about network information through a PDA or mobile device with GNSS on board. In this way, the network component, its description, and coordinates are recorded in field and loaded in real time to the database; +- The back office process: During this step, the operator should access the district database, validate collecting data and transfer data on the final project; +- In order to collect data about buried infrastructure, georadar with GNSS (or differential global navigation satellite system (DGNSS)) should be used. Then all collected data should be loaded to the database. + +All data, both edited with CAD and collected with mobile device and georadar machine should be visualized both in CAD and GIS and they should be created with the same geographical coordinate system, such as the international standard world geodetic system – 1984 (WGS-84). + +It is recommended to collect and geo-reference data about all outdoor infrastructure components and buildings, such as central offices and customer premises where indoor elements, equipment, or optical distribution frames are installed. + +## **12 Local and remote database** + +The geo-referenced system should be an appropriate application, such as a web-based system, in order to have a user-friendly interface. In terms of the local database, it should be possible to associate in-field information directly to the network element, recorded with an ID tag applied to it, as described in [ITU-T L.64]. + +Using the remote database, it should be possible to choose the central office area in order to visualize only the infrastructure of a specific zone and its component. Furthermore, it should be possible to select a layer of the network that contains a certain kind of information. For example, you could see only the telecommunication copper network or only empty ducts. + +## Appendix I + +### Italian experience regarding geo-referencing system + +(This appendix does not form an integral part of this Recommendation.) + +A solution has been developed and designed for asset management and collection of telecommunication infrastructure. The solution provides comprehensive support for inventory, management and maintenance of company assets, as well as procurement activities. + +It gives the end user the ability to collect, analyse, display assets, locations and work orders in a geospatial perspective. + +With the use of a mobile terminal, field technicians are able to work remotely and interact with business processes and data on the platform. + +In a cloud environment and with the use of digital maps, it is possible to represent any type of network object, identify directly from the field, and update the central database for sharing data within other companies. + +![Diagram of the collecting system showing data flow from a field camera, a mobile terminal, and a satellite to a central database.](8e14350b4b669119a3bdfca7869110ca_img.jpg) + +The diagram illustrates the data collection process. On the left, a camera captures a field view of a utility pole. A yellow arrow points from this camera to a central mobile terminal (a ruggedized smartphone) being used by a person. Another yellow arrow points from a satellite in space to the same mobile terminal. A large red arrow points from the mobile terminal down to a box labeled "Central Database with Management System". + +Diagram of the collecting system showing data flow from a field camera, a mobile terminal, and a satellite to a central database. + +**Figure I.1 – Collecting system** + +This proprietary platform is integrated with a workflow management and collaborative working platform for a better management of the life processes of infrastructure. + +This platform is a software solution based on the SaaS paradigm (Software as a Service), reachable from any device with web access. + +It also has a geospatial search engine that lets you view the results on a map. Advanced searches can be performed by filtering based on address, city, region, nation, or geospatial coordinates. + +Image: Screenshot of the asset browsing interface showing search filters, a data table, and a map view. + +The screenshot shows the asset browsing interface. At the top, there is a search bar with a dropdown menu for "DESCRIPTION" containing the text "roma". Below the search bar is a "Search Engine" section with a table listing assets. To the right, a map view shows a location in Rome with a pop-up window for a selected asset. Red arrows indicate the flow from the search filters to the map and from the search results table to the map. + +| NO | ITEM ID | DESCRIPTION | LAT | LON | ALT | +|----|---------|-------------|-----------|-----------|------| +| 32 | PMU_17 | PMU_17 | 41.901234 | 12.493456 | 45.0 | +| 33 | PMU_18 | PMU_18 | 41.901234 | 12.493456 | 45.0 | +| 34 | PMU_19 | PMU_19 | 41.901234 | 12.493456 | 45.0 | +| 35 | PMU_20 | PMU_20 | 41.901234 | 12.493456 | 45.0 | +| 36 | PMU_21 | PMU_21 | 41.901234 | 12.493456 | 45.0 | +| 37 | PMU_22 | PMU_22 | 41.901234 | 12.493456 | 45.0 | +| 38 | PMU_23 | PMU_23 | 41.901234 | 12.493456 | 45.0 | +| 39 | PMU_24 | PMU_24 | 41.901234 | 12.493456 | 45.0 | +| 40 | PMU_25 | PMU_25 | 41.901234 | 12.493456 | 45.0 | +| 41 | PMU_26 | PMU_26 | 41.901234 | 12.493456 | 45.0 | + +**Figure I.2 – Browsing asset (Source: Google Maps)** + +Through this tool, the user can check online customer report parameters. The system allows configurable graphical representation of the data (pie, line, histogram, etc.) and it is possible to extract the results of the reports in different file formats. + +Using the GNSS-enabled mobile terminal, it is possible to collect data of an asset and capture its GNSS position. Once the operation is completed, the device automatically sends the data to the cloud. + +If it is necessary, the information digitalized from the field can be adjusted or integrated in a back office environment. + +![Screenshot of a map editing interface showing a satellite view of a building. A pop-up window displays 'Data updated' and 'OK'. Another pop-up shows 'NEW Lat: 42.301982718177' and 'NEW Lon: 12.2288828274488'. The interface includes a table with columns: ITEM ID n., DESCRIPTION, LAT, LNC. The table row shows: FAL0_37, 42.433247, 12.228847.](10953d657a5f47fdc829a800419dd370_img.jpg) + +Screenshot of a map editing interface showing a satellite view of a building. A pop-up window displays 'Data updated' and 'OK'. Another pop-up shows 'NEW Lat: 42.301982718177' and 'NEW Lon: 12.2288828274488'. The interface includes a table with columns: ITEM ID n., DESCRIPTION, LAT, LNC. The table row shows: FAL0\_37, 42.433247, 12.228847. + +**Figure I.3 – Editing asset on a map (Source: Google Maps)** + +In the Italian system, it is possible to import all types of geo-referenced data, such as the information about underground utilities, by georadar analysis, or existing cartography. + +![Illustration of data integration. On the left, a mobile terminal (GNSS receiver) is shown. A chain connects it to a yellow figure holding a chain. The chain connects to a map showing underground utilities.](7b4218684dabfd7cc15685f82dbe5faf_img.jpg) + +Illustration of data integration. On the left, a mobile terminal (GNSS receiver) is shown. A chain connects it to a yellow figure holding a chain. The chain connects to a map showing underground utilities. + +**Figure I.4 – Data integration** + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file