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.26 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 aerial application Recommendation ITU-T L.26 Rec. ITU-T L.26 (08/2015) i Recommendation ITU-T L.26 Optical fibre cables for aerial application Summary Recommendation ITU-T L.26 describes characteristics, construction and test methods of optical fibre cables for aerial ap
3、plication (including lashed cables), but does not apply to optical ground wire (OPGW) cables or metal armour self-supporting (MASS) cables. First, the characteristics affecting the satisfactory performance of optical fibre cables are described. Then, the methods of examining whether the cables have
4、these required characteristics are described. The conditions required may differ according to the installation environment. Therefore, 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 Reco
5、mmendation Approval Study Group Unique ID* 1.0 ITU-T L.26 1996-10-18 6 11.1002/1000/3890 2.0 ITU-T L.26 2002-12-22 6 11.1002/1000/6136 3.0 ITU-T L.26 2015-08-13 15 11.1002/1000/12533 _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, follow
6、ed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T L.26 (08/2015) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies
7、(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 Telecommunicat
8、ion 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 in
9、formation 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 expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating a
10、gency. 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 s
11、ome 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 RIGHTSITU draws attention to the possibility that the practice or
12、 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 p
13、rocess. 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 stro
14、ngly 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 whatsoever, without the prior written permission of ITU. Rec. ITU-T L.26 (08/2015) iii Table of Contents Page 1 Scope . 1 2 Referen
15、ces . 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 4 6 Characteristics of optical fibres and cables 4 6.1 Optical fibre characteristics 4 6.2 Mechanical characteristics 4 6.3 Environmental conditions . 5 7 C
16、able construction 7 7.1 Fibre coatings . 7 7.2 Cable elements 8 7.3 Sheath . 10 7.4 Armour . 10 7.5 Identification of cable . 10 7.6 Cable sealing 11 8 Test methods . 11 8.1 Test methods for cable elements 11 8.2 Test methods for mechanical characteristics of the cable 12 8.3 Test methods for enviro
17、nmental characteristics . 13 Bibliography. 15 Rec. ITU-T L.26 (08/2015) 1 Recommendation ITU-T L.26 Optical fibre cables for aerial application 1 Scope This Recommendation: refers to single-mode optical fibre cables to be used in telecommunication networks for aerial installations in outside plants,
18、 excluding optical ground wire (OPGW) and metal armour self-supporting (MASS) cables; considers the mechanical and environmental characteristics of the aerial optical fibre cable (self-supporting cable and non self-supporting cable). The optical fibre dimensional and transmission characteristics, to
19、gether 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 fundamental aspects related to optical fibre cable from mechanical and environmental points of view. 2 References The following
20、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 Recommenda
21、tion 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
22、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 for stat
23、istical 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 index optic
24、al 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 Recommendati
25、on ITU-T G.654 (2012), 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 fi
26、bre 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. 2 Rec. ITU-T L.26 (08/2015) ITU-T K.29 Recommendation ITU-T K.29 (1992), Coo
27、rdinated 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 telecommunication cables
28、 in public networks. ITU-T L.14 Recommendation ITU-T L.14 (1992), Measurement method to determine the tensile performance of optical fibre cables under load. 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 Recommend
29、ation ITU-T L.46 (2000), Protection of telecommunication cables and plant from biological attack. IEC 60793-1-1 IEC 60793-1-1 (2008), Optical fibres Part 1-1: Measurement methods and test procedures General and guidance. IEC 60793-1-21 IEC 60793-1-21 (2001), Optical fibres Part 1-21: Measurement met
30、hods and test procedures Coating geometry. 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 mul
31、timode fibres. 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
32、fibre cables 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), Optica
33、l fibre cables 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)
34、, Optical fibre cables Part 3: Outdoor cables Sectional specification. IEC 60794-3-10 IEC 60794-3-10 (2014), Optical fibre cables Part 3-10: Outdoor cables Family specification for duct, directly buried, and lashed aerial single-mode optical fibre telecommunication cables. IEC 60794-3-20 IEC 60794-3
35、-20 (2009), Optical fibre cables Part 3-20: Outdoor cables Family specification for self-supporting aerial telecommunication cables. IEC 60794-4-20 IEC 60794-4-20 (2012), Optical fibre cables Part 4-20: Aerial optical cables along electrical power lines Family specification for ADSS (All Dielectric
36、Self Supported) optical cables. Rec. ITU-T L.26 (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 (2012), Electric and optical
37、fibre cables Test methods for non-metallic materials Part 203: General tests Measurement of overall dimensions. ISO 4892-2 ISO 4892-2 (2013), Plastics Methods of exposure to laboratory light sources Part 2: Xenon-arc lamps. IEEE 1222 IEEE 1222 (2011), IEEE Standard for Testing and Performance for Al
38、l-Dielectric Self-Supporting (ADSS) Fiber Optic Cable for Use on Electric Utility Power Lines. 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 ITU-T G.651.1 apply. 3.2 Terms defined in this Re
39、commendation This Recommendation defines the following terms: 3.2.1 all-dielectric self-supporting (ADSS): Cable in which the tensile element is provided by a non-metallic reinforcement (e.g., aramid yarns, glass-fibre-reinforced materials or equivalent dielectric strength members) placed under or w
40、ithin the plastic sheath; the outer shape is circular. 3.2.2 differential movement of cable components: The relative movement of various elements of the cable to one another. This movement can either be reversible or irreversible. It can be induced by temperature or tension variation. An example of
41、this is fibre grow-out, in which individual fibres begin to protrude from the end of the cable sheath. 3.2.3 lashed cable on messenger wire: Non-metallic or armoured cables installed on a separate suspension catenary and held in position with a binder cord or special preformed spiral clips. 3.2.4 ma
42、ximum allowable tension: The maximum tensile load that may be applied to the cable without detriment to the tensile performance requirement (optical performance, fibre strain). 3.2.5 rated tensile strength: Summation of the product of nominal cross-sectional area, minimum tensile strength and strand
43、ing factor for each load-bearing material in the cable construction. 3.2.6 self-supporting cable: Cable in which the sheath includes a metallic or non-metallic bearing element(s), most commonly forming a figure 8. 3.2.7 strain margin: The amount of strain the cable can sustain without strain on the
44、fibres due to cable elongation. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: ADSS All-Dielectric Self-Supporting MASS Metal Armour Self-Supporting OPAC Optical Attached Cable OPGW Optical Ground Wire 4 Rec. ITU-T L.26 (08/2015) SZ Reverse oscillatin
45、g stranding UV Ultraviolet 5 Conventions None. 6 Characteristics of optical fibres and cables 6.1 Optical fibre characteristics Optical fibres should be used as described in: ITU-T G.651.1, ITU-T G.652, ITU-T G.653, ITU-T G.654 or ITU-T G.655, ITU-T G.656 or ITU-T G.657. 6.1.1 Transmission character
46、istics The typical transmission characteristics for each type of optical fibre are described in their respective Recommendation. Unless specified otherwise by the users of the Recommendation, those values apply to the corresponding cabled optical fibre. 6.1.2 Fibre microbending Severe bending of an
47、optical fibre involving local axial displacement of a few micrometres over short distances, caused by localized lateral forces along its length, is called microbending. This may be caused by manufacturing and installation strains or by dimensional variations of cable materials due to temperature cha
48、nges during operation. 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 eliminated during the incorporation of the fibres into the cable, as well as during and after cable installation. 6.1.3 Fibre m
49、acrobending Macrobending is the resulting curvature of an optical fibre, which is large relative to the fibre diameter, after cable manufacture and installation. Macrobending can cause an increase in optical loss. The optical loss increases inversely to the bending radius of the fibre; the macrobending should not be severe enough to significantly increase the opt
