1、 International Telecommunication Union ITU-T L.78TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1(06/2010) SERIES L: CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT Optical fibre cable construction for sewer duct applications Amendment 1: New Append
2、ix III Italian experience: Construction of special optical fibre cables for extreme applications in sewer ducts Recommendation ITU-T L.78 (2008) Amendment 1 Rec. ITU-T L.78 (2008)/Amd.1 (06/2010) i Recommendation ITU-T L.78 Optical fibre cable construction for sewer duct applications Amendment 1 New
3、 Appendix III Italian experience: Construction of special optical fibre cables for extreme applications in sewer ducts Summary Amendment 1 of Recommendation ITU-T L.78 provides an new appendix describing the Italian experience related to “optical fibre cable construction for sewer duct applications“
4、. This appendix may be useful for readers who intend to install optical fibre cables into specific sewer ducts (e.g., high water pressure and corrosive materials). History Edition Recommendation Approval Study Group 1.0 ITU-T L.78 2008-05-29 6 1.1 ITU-T L.78 (2008) Amend. 1 2010-06-11 15 ii Rec. ITU
5、-T L.78 (2008)/Amd.1 (06/2010) 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
6、. 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 fo
7、r 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-Ts purview, the necessary standards are prepared
8、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 con
9、tain 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
10、 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 Propert
11、y 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 in
12、tellectual 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 http:/www.itu.int/ITU-T/ipr/. ITU 2010 All
13、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.78 (2008)/Amd.1 (06/2010) iii CONTENTS Page Amendment 1 New Appendix III Italian experience: Construction of special optical fibre cables for extreme app
14、lications in sewer ducts 1 III.1 General design of the cable 1 III.2 Description of cable structure . 1 III.3 Main performance characteristics of the cable . 1 III.4 Benefits by using this cable 2 III.5 Fibres 2 Rec. ITU-T L.78 (2008)/Amd.1 (06/2010) 1 Recommendation ITU-T L.78 Optical fibre cable c
15、onstruction for sewer duct applications Amendment 1 New Appendix III Italian experience: Construction of special optical fibre cables for extreme applications in sewer ducts (This appendix does not form an integral part of this Recommendation) III.1 General design of the cable The cable should not b
16、e considered as a reinforced cable, based on the normal stranded plastic loose tube, but a new “concept cable“. The fibres are inside stranded stainless steel loose tube (SSLT) laser welded, which guarantees maximum robustness and corrosion resistance. The above-mentioned construction concept is ver
17、y important in order to achieve the mechanical performance required for such an application. Tensile performance as well as crush resistance and flexibility are the main parameters to take into account while using this cable. Water penetration (especially inside sewer pipes) is also a very important
18、 issue, which should be treated in a proper way. III.2 Description of cable structure Central element made of high galvanized steel wire(s). Optical core: 4 to 48 fibres in each stainless steel loose tube, each filled with a non-hygroscopic jelly compound. 1 to 9 stainless steel loose tubes are stra
19、nded with high galvanized steel wires. Protection: Special polymer (filling compound) injected around the high galvanized steel wires. Mechanical protection: high galvanized steel wires preformed and stranded according to cable design. External sheath: special polymer, 2.2 mm thick, which turns slip
20、pery at the contact with liquids, in order to enhance debris transit. III.3 Main performance characteristics of the cable Very high tensile strength, e.g., 290 kN for 144 fibres. Extremely high crush resistance of up to 4000 N/cm (depending on construction). Small cable diameter, e.g., 14.2 mm for 2
21、4 fibres, 22 mm for 144 fibres, 30 mm for 432 fibres. Small bending radius: 15 times the cable diameter. Excellent chemical resistance to sewage and other chemicals. Absolutely protected against rodents. Resistant to high pressure water jet cleaning of sewers. Free of residual torque or stress, due
22、to preformed stranded construction (no bending memory effect). The cable is installed using conventional techniques, e.g., by pulling. There is no need for special investments or expensive installation with robots. 2 Rec. ITU-T L.78 (2008)/Amd.1 (06/2010) Sufficient cable weight in water allows the
23、cable to be laid directly on the bottom of the sewer, without any fixing point. No problems with different thermal dilatation by using stainless steel loose tubes and steel wires. Excellent resistance to water penetration due to a thick sheathing, special filling compound and a stainless steel loose
24、 tube with jelly filling. Sheath material becomes slippery in contact with water to facilitate the debris transit. III.4 Benefits of using this cable Easy and fast installation using conventional cable deployment equipment. Fixing of the cable is not necessary since the cable positions itself straig
25、ht on the bottom, and is sufficiently strong and heavy to remain in this place. There is very little interference with traffic when deploying this cable. The cable withstands sewer cleaning with high pressure water jets, hence it must not be removed. III.5 Fibres The fibres are in accordance with IT
26、U-T recommendations. The cable can be equipped with ITU-T G.652, ITU-T G.655, ITU-T G.656 or any other type of telecommunication fibre as well as hybrid solutions. Maximum number of fibres: 432 with 9 stainless steel loose tubes (SSLT). III.5.1 Fibre identification The fibre count within a SSLT vari
27、es from 4 to 48, the number of SSLT from 1 to 9, depending on customer specification and detailed construction. The SSLT are marked with tracer tape for identification. The fibres inside the SSLT are identified by colours: Fibres 1-12 are identified by 12 different colours. Fibres 13-48 are identifi
28、ed by using black ring markings in different numbers and distances together with the fibre colouring as for fibres 1-12 (exception: black colour is replaced by transparent), see Table III.1. The colour code can be adapted according to customer requirements. 1. High galvanized steel2. Stainless steel
29、 loose tube (SSLT)3. Filling compound4. Special polymer sheathL.78(10)_FIII.1Figure III.1 Example construction for optical fibre cables for extreme applications in sewers or water conduits Rec. ITU-T L.78 (2008)/Amd.1 (06/2010) 3 Table III.1 Standard colour code of identification No. Fibres Colour 1
30、, 13, 25, 37 Red 2, 14, 26, 38 Green 3, 15, 27, 39 Yellow 4, 16, 28, 40 Blue 5, 17, 29, 41 White 6, 18, 30, 42 Violet 7, 19, 31, 43 Orange 8, 20, 32, 44 Black, transparent 9, 21, 33, 45 Grey 10, 22, 34, 46 Brown 11, 23, 35, 47 Pink 12, 24, 36, 48 Aqua Table III.2 Mechanical characteristics of the ca
31、ble Standard Nominal values Example for 144 fibers Diameter (mm) 14.2-30 22.4 Estimated weight (kg/m) 0.54-2.77 1.56 Minimum bending radius (mm) IEC 60794-1-2, E11A 15 d with tensile load: 20 d 336 448 Tensile performance (kN) IEC 60794-1-2, E1B 89-535 296 Crush resistance (N/cm) IEC 60794-1-2, E3 8
32、00-4000 4000 Temperature cycling IEC 60794-1-2, F1 40-+60C 40-+60C Printed in Switzerland Geneva, 2010 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 fact
33、ors 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 multi
34、media 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 tran
35、smission 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 Tele
36、graph 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
