1、BSI Standards Publication Hydrogen effects in optical fibre cables Guidelines PD IEC/TR 62690:2014National foreword This Published Document is the UK implementation of IEC/TR 62690:2014. The UK participation in its preparation was entrusted by Technical Committee GEL/86, Fibre optics, to Subcommitte
2、e GEL/86/1, Optical fibres and cables. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards
3、Institution 2014. Published by BSI Standards Limited 2014 ISBN 978 0 580 72082 6 ICS 33.180.10 Compliance with a British Standard cannot confer immunity from legal obligations. This Published Document was published under the authority of the Standards Policy and Strategy Committee on 31 July 2014. A
4、mendments/corrigenda issued since publication Date Text affected PUBLISHED DOCUMENT PD IEC/TR 62690:2014IEC TR 62690 Edition 1.0 2014-06 TECHNICAL REPORT Hydrogen effects in optical fibre cables Guidelines INTERNATIONAL ELECTROTECHNICAL COMMISSION J ICS 33.180.10 PRICE CODE ISBN 978-2-8322-1657-6 Re
5、gistered trademark of the International Electrotechnical Commission Warning! Make sure that you obtained this publication from an authorized distributor. colour inside PD IEC/TR 62690:2014 2 IEC TR 62690:2014 IEC 2014 CONTENTS FOREWORD . 3 INTRODUCTION . 5 1 Scope 6 2 Normative references 6 3 Genera
6、l . 6 4 Evaluation of hydrogen induced effects . 6 5 Hydrogen effects in optical fibre cables . 7 Bibliography 9 Table 1 Evaluation criteria for single-mode (SM) optical fibre cables 7 PD IEC/TR 62690:2014IEC TR 62690:2014 IEC 2014 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ HYDROGEN EFFECTS IN OP
7、TICAL FIBRE CABLES GUIDELINES FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions con
8、cerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Th
9、eir preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non- governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates
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11、elevant subjects since each technical committee has representation from all interested IEC National Committees. 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that t
12、he technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maxi
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14、provide conformity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by independent certification bodies. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC
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16、enses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications. 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Att
17、ention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. The main task of IEC technical committees is to prepare International Standards. However, a techn
18、ical committee may propose the publication of a technical report when it has collected data of a different kind from that which is normally published as an International Standard, for example “state of the art“. IEC TR 62690, which is a technical report, has been prepared by subcommittee 86A: Fibres
19、 and cables, of IEC technical committee 86: Fibre optics. The text of this technical report is based on the following documents: Enquiry draft Report on voting 86A/1586/DTR 86A/1605/RVC Full information on the voting for the approval of this technical report can be found in the report on voting indi
20、cated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. PD IEC/TR 62690:2014 4 IEC TR 62690:2014 IEC 2014 The committee has decided that the contents of this publication will remain unchanged until the stability dateindicated on the IEC web site
21、 under “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be reconfirmed, withdrawn, replaced by a revised edition, or amended. A bilingual version of this publication may be issued at a later date. IMPORTANT The colour inside logo on the cove
22、r page of this publication indicates that it contains colours which are considered to be useful for the correct understanding of its contents. Users should therefore print this document using a colour printer. PD IEC/TR 62690:2014IEC TR 62690:2014 IEC 2014 5 INTRODUCTION There is extensive applicati
23、on of optical fibre cables worldwide, both for terrestrial and submarine environments, with the provision of stable transmission characteristics over many years. In the early 1980s, it was established that some optical fibre designs in certain cable constructions were prone to hydrogen-induced atten
24、uation increases. The mechanism of the hydrogen induced loss was quickly established and after extensive research and development programs, fibre designs were optimized to minimize the effects. Cable designers established suitable design rules and optimized the selection of cable materials so as to
25、also minimize the effects of hydrogen induced attenuation increases during service life. PD IEC/TR 62690:2014 6 IEC TR 62690:2014 IEC 2014 HYDROGEN EFFECTS IN OPTICAL FIBRE CABLES GUIDELINES 1 Scope The purpose of this technical report is to provide information concerning the behaviour of fibres and
26、 cables when exposed to hydrogen effects. The application of multimode fibres is very rarely subject to hydrogen effects. For that reason, this technical report only highlights the effects of hydrogen to single-mode fibres. 2 Normative references The following documents, in whole or in part, are nor
27、matively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60794-3, Optical fibre cables Part 3: Sectional specific
28、ation Outdoor cables IEC 60794-4, Optical fibre cables Part 4: Sectional specification Aerial optical cables along electrical power lines IEC 60794-5,Optical fibre cables Part 5: Sectional specification Microduct cables for installation by blowing 3 General The magnitude of any hydrogen induced effe
29、ct depends on the cable type (including fibre design) and its operational environment. In the case of suitably designed, single-mode fibre cables for terrestrial applications, there is sufficient experience to not require any test in cables for significant concentrations of hydrogen which could caus
30、e an increase in optical attenuation. The induced loss for single-mode fibre due to hydrogen at a partial pressure of up to 1,0 10 4 Pa (9,9 10 2atm) is no greater than 0,03 dB/km and 0,06 dB/km, at 1 310 nm and 1 550 nm, respectively. The dynamic equilibrium pressure or balance of hydrogen within a
31、 terrestrial cable with no hermetic barrier will be significantly less than 1,0 10 4 Pa, and therefore, optical reliability is ensured. Typical values of 40,5 Pa equivalent to 4,0 10 4atm have been measured for duct cable several years after installation 1 1 . At these partial pressures, the attenua
32、tion increase is insignificant. 4 Evaluation of hydrogen induced effects Depending on the cable type and its planned operational environment, an evaluation of hydrogen induced effects 2 may or may not be warranted. Table 1 offers a guide to the necessity to evaluate cables for hydrogen induced atten
33、uation increases. _ 1Numbers in square brackets refer to the Bibliography PD IEC/TR 62690:2014IEC TR 62690:2014 IEC 2014 7 Table 1 Evaluation criteria for single-mode (SM) optical fibre cables Cable construction Application / environment Direct-buried IEC 60794-3-10 Duct IEC 60794-3-10 Aerial IEC 60
34、794-3-20 Shallow water aIEC 60794-3-10 Underwater aIEC 60794-3-30 Metallic 1(See Note) 1 1 2 2 Non-metallic 1 1 1 1 b Hermetic barrier (i.e. metallic tube) 2 c2 2 2 2 NOTE No evaluation. aShallow water Less than 10 m water depth, short distance. Underwater 10 m or greater water depth, as for true su
35、bmarine cable and the like. bCable constructions not applicable. Other cable types of IEC 60794-3, IEC 60794-4 and IEC 60794-5 may be evaluated for testing, in accordance with this report. c Evaluation is recommended at the research and developement phase of the cable construction involved. Use of h
36、ydrogen-absorbing materials in the cable construction may obviate the need for evaluation in cable form. 5 Hydrogen effects in optical fibre cables NOTE As indicated in Clause 1, the application space of multimode fibres is rarely subject to hydrogen effects. The theoretical effects of hydrogen on m
37、ultimode fibres is presented in this clause for the information of users. Both single-mode and multimode optical fibre cables can optically degrade due to the accumulation of hydrogen gas within the cable structure during its operational lifetime. The magnitude of the effect depends on the following
38、 factors: the fibre type, its dopant composition/concentration and its intrinsic susceptibility to hydrogen; the levels of hydrogen gas (i.e. partial pressure) generated in the cable during its operational lifetime; the design of the cable and, in particular, the choice and combination of materials
39、used in its construction; the installation environment, including its operational temperature. Hydrogen gas may build up within a cable from: hydrogen released from the cable components, including that associated with long-term ageing effects of the materials; hydrogen contained in pressurised air p
40、umped into the cable; corrosion action of metallic elements in the presence of moisture; biological corrosion by sulphate reducing bacteria. The optical loss mechanisms due to hydrogen can be classified as follows: a reversible interstitial effect associated with diffusion of the H 2molecules into t
41、he silica glass fibre. The effect is very similar for all fibre types (both multimode and single-mode) and its magnitude is linear with the partial pressure of hydrogen; a permanent chemical effect due to hydroxyl formation through chemical combination of diffused hydrogen molecules and defect sites
42、 in the silica glass fibre. The magnitude of the effect is related to the square root of the partial pressure of hydrogen. For single-mode fibres, the permanent loss will be much smaller than the interstitial loss even after 25 years in a hostile operational environment: a wavelength dependent loss,
43、 which is only experienced at elevated temperatures (in excess of 60 C) in single-mode fibres, and is again much smaller than the interstitial loss observed at ambient temperature; PD IEC/TR 62690:2014 8 IEC TR 62690:2014 IEC 2014 monitoring the loss increases at the characteristic wavelength of 1 2
44、40 nm and 1 380 nm is a good indicator of both the interstitial and permanent chemical effects. PD IEC/TR 62690:2014IEC TR 62690:2014 IEC 2014 9 Bibliography 1 HORNUNG, S., CASSIDY, S.A., REEVE, M.H. “The distribution of H2 gas along an inland optical fibre cable“. Symposium of Optical Fibre Measure
45、ments 1984, National Bureau of Standards, NSB-SP-683, pp. 85-88, Oct. 1984 2 ITU-T Recommendation L.27(10/96), Method for estimating the concentration of hydrogen in optical fibre cables _ PD IEC/TR 62690:2014This page deliberately left blankThis page deliberately left blankBSI is the national body
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