1、 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 L.43 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (08/2015) SERIES L: ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PL
2、ANT Optical fibre cables for buried application Recommendation ITU-T L.43 Rec. ITU-T L.43 (08/2015) i Recommendation ITU-T L.43 Optical fibre cables for buried application Summary Recommendation ITU-T L.43 describes characteristics, construction and test methods of optical fibre cables for buried ap
3、plication. First, the characteristics affecting the satisfactory performance of optical fibre cables are described. Then, the methods of examining whether the cables have these required characteristics are described. The conditions required may differ according to the installation environment. There
4、fore, detailed conditions of experiments need to be agreed upon between a user and a supplier on the basis of the environment where the cable is used. 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.43 2015-08-13 15 11.1002/100
5、0/12531 _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T L.43 (08/2015) FOREWORD The International Telecommunication Union (
6、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 i
7、ssuing 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
8、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-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the express
9、ion “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 applicabili
10、ty) 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 Rec
11、ommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU 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 o
12、f 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
13、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 http:/www.itu.int/ITU-T/ipr/. ITU 2015 All rights reserved. No part of this publication may be reproduced, by any means whatso
14、ever, without the prior written permission of ITU. Rec. ITU-T L.43 (08/2015) iii 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 the opti
15、cal fibres and cables . 3 6.1 Optical fibre characteristics 3 6.2 Mechanical characteristics 4 6.3 Environmental conditions . 4 6.4 Installation near high-voltage power line . 6 7 Cable construction 6 7.1 Fibre coatings . 6 7.2 Cable elements 7 7.3 Sheath . 9 7.4 Armour . 9 7.5 Identification of cab
16、le . 9 7.6 Cable sealing 10 8 Test methods . 10 8.1 Test methods for cable element 10 8.2 Test methods for mechanical characteristics of the cable 11 8.3 Test methods for environmental characteristics . 12 Bibliography. 15 Rec. ITU-T L.43 (08/2015) 1 Recommendation ITU-T L.43 Optical fibre cables fo
17、r 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 extension of un
18、derground facilities like ducts and tunnels. When they are 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 Recommenda
19、tion: refers to multi-mode graded index and single-mode optical fibre cables to be used for telecommunication networks in direct buried installations; considers the mechanical and environmental characteristics of the optical fibre cables. The optical fibre dimensional and transmission characteristic
20、s, together with their test methods, should comply with one or more 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 or ITU-T G.657; considers the fundamental aspects related to optical fibre cable from mechanical and environmental points of view. 2 References The f
21、ollowing 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 R
22、ecommendation 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
23、not give it, as a stand-alone document, the status of a Recommendation. ITU-T G.650.1 Recommendation ITU-T G.650.1 (2010), 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 (2007), Definitions and test methods
24、 for statistical and non-linear related attributes of single-mode fibre and cable. ITU-T G.650.3 Recommendation ITU-T G.650.3 (2008), Test methods for installed single-mode optical fibre cable links. ITU-T G.651.1 Recommendation ITU-T G.651.1 (2007), Characteristics of a 50/125 m multimode graded in
25、dex optical fibre cable for the optical access network. ITU-T G.652 Recommendation ITU-T G.652 (2009), 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 Rec
26、ommendation ITU-T G.654 (2012), Characteristics of a cut-off shifted single-mode optical fibre and cable. 2 Rec. ITU-T L.43 (08/2015) 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
27、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 (2012), Characteristics of a bending-loss insensitive single-mode optical fibre and cable for the access network. ITU-T K.29 Recommendation ITU-T K.29 (1
28、992), 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.1 Recommendation ITU-T L.1 (1988), Construction, installation and protection of telecommunicati
29、on cables in public networks. ITU-T L.27 Recommendation ITU-T L.27 (1996), Method for estimating the concentration of hydrogen in optical fibre cables. ITU-T L.46 Recommendation ITU-T L.46 (2000), Protection of telecommunication cables and plant from biological attack. IEC 60793-1-1 IEC 60793-1-1 (2
30、008), Optical fibres Part 1-1: Measurement methods and test procedures General guidance. IEC 60793-1-21 IEC 60793-1-21 (2001), Optical fibres Part 1-21: Measurement methods and test procedures Coating geometry. IEC 60793-1-30 IEC 60793-1-30 (2010), Optical fibres Part 1-30: Measurement methods and t
31、est procedures Fibre proof test. IEC 60793-1-32 IEC 60793-1-32 (2010), Optical fibres Part 1-32: Measurement methods and test procedures Coating strippability. IEC 60793-2-10 IEC 60793-2-10 (2011), Optical fibres Part 2-10: Product specifications Sectional specification for category A1 multimode fib
32、res. IEC 60793-2-50 IEC 60793-2-50 (2012), Optical fibres Part 2-50: Product specifications Sectional specification for class B single-mode fibres. IEC 60794-1-1 IEC 60794-1-1(2011), Optical fibre cables Part 1-1: Generic specification General. IEC 60794-1-2 IEC 60794-1-2 (2013), Optical fibre cable
33、s Part 1-2: Generic specification Cross reference 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 c
34、ables Part 1-22: Generic specification Basic optical cable test procedures Environmental tests methods. IEC 60794-1-23 IEC 60794-1-23 (2012), Optical fibre cables Part 1-23: Generic specification Basic optical cable test procedures Cable elements test methods. IEC 60794-3 IEC 60794-3 (2014), Optical
35、 fibre cables Part 3: Outdoor cables Sectional specification. Rec. ITU-T L.43 (08/2015) 3 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
36、 (2012), Electric and optical fibre cables Test methods for non-metallic materials Part 203: General tests Measurement of overall dimensions. 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 IT
37、U-T G.651 apply. 3.2 Terms defined in this Recommendation None. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: SZ Reverse oscillating stranding 5 Conventions None. 6 Characteristics of the optical fibres and cables 6.1 Optical fibre characteristics Op
38、tical fibres should be used described in: 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 or ITU-T G.657. 6.1.1 Transmission characteristics The typical transmission characteristics for each type of optical fibre are described in their respective Recommendation. Unless
39、 specified by the users of this specific Recommendation, those values are applied for a cabled optical fibre. 6.1.2 Fibre microbending 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,
40、 is called microbending. This may be caused by manufacturing and installation strains and by dimensional variations of cable materials due to temperature changes during operation. Microbending can cause an increase in optical loss. In order to reduce microbending loss, stress randomly applied to a f
41、ibre along its axis should be eliminated during the incorporation of the fibres into the cable, as well as during and after cable installation. 6.1.3 Fibre macrobending Macrobending is the resulting curvature of an optical fibre after cable manufacture and installation. Macrobending can cause an inc
42、rease in optical loss. The optical loss increases if the bending radius is too small. 4 Rec. ITU-T L.43 (08/2015) NOTE ITU-T G.657 optical fibres are optimized for reduced macrobending loss. 6.2 Mechanical characteristics 6.2.1 Bending Under the dynamic conditions encountered during installation, th
43、e fibre is subjected to strain from both cable tension and bending. The strength elements in the cable and the installation bend radius must be selected to limit this combined dynamic strain. Any fibre bend radius remaining after cable installation shall be large enough to limit the macrobending los
44、s or the long-term strains, which shorten the life of the fibre. 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 during operation (e.g., temperature variation). C
45、hanges in the tension of the cable due to a variety of factors encountered during the service life of the cable can cause a differential movement of the cable components. This effect needs to be considered in the cable design. Excessive tensile loading increases the optical loss of the cable and may
46、 cause increased residual strain in the fibre if the cable cannot relax. To avoid this, the maximum tensile strength determined by the cable construction, and more importantly by the design of the strength member, should not be exceeded. NOTE Where a cable is subjected to permanent loading during it
47、s operational life, the fibre should preferably not experience additional strain. 6.2.3 Crush and impact The cable may be subjected to crush and impact during both installation and operational life. The crush and impact may increase the optical loss (permanently or for the period of time during the
48、application of the stress) and excessive stress may lead to fibre fracture. 6.2.4 Torsion Under dynamic conditions encountered during installation and operation, the cable may be subjected to torsion, resulting in residual strain on the fibres and/or damage of the sheath. If this is the case, the ca
49、ble design should allow a specified number of cable twists per unit length without an increase in fibre loss and/or damage to the sheath. 6.3 Environmental conditions 6.3.1 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 concentration in t
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