GB/Z 41287.2-2022Optical fibre telecommunication cables for use in premises cabling - Part 2:Optical fibre cables for self-supporting aerial application (English PDF)

Foreword

This document was drafted in accordance with the rules given in GB/T 1.1-2020, Directives for standardization - Part 1: Rules for the structure and drafting of standardizing documents.

This document is Part 2 of GB/Z 41287, Optical fibre telecommunication cables for use in premises cabling. The following parts of GB/Z 41287 have been published: Part 1: Optical fibre cables for duct and direct buried application; Part 2: Optical fibre cables for self-supporting aerial application.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.

This document was proposed by and is under the jurisdiction of the Ministry of Industry and Information Technology of the People's Republic of China.

The drafting organizations of this document are Chengdu Datang Cable Co., Ltd., Chengdu Tairui Communication Equipment Testing Co., Ltd., Sichuan Huiyuan Optical Communications Co., Ltd., Yangtze Optical Fibre and Cable Joint Stock Limited Company, China Academy of Information and Communications Technology, Jiangsu Hengtong Optic-Electric Co., Ltd., FiberHome Technologies Group Co., Ltd., Jiangsu Junzhi Technology Co., Ltd., Chengdu Hengtong Optical Communication Co., Ltd., Jiangsu Etern Co., Ltd., China Academy of Telecommunications Technology Co., Ltd. and Jiangsu Nanfang Communications Technology Co., Ltd.

The main drafters of this document are Huang Kun, Peng Yuan, Xue Mengchi, Liu Tai, Lv Jie, Xu Jiangbo, Song Zhituo, Shi Bin, Luo Yi, Xiong Zhuang, Liu Xiangrong, Wang Yaoming, Chen Xiaohong, Wang Zemin, Yuan Fan, Li Jichao, Gao Hua, Huang Zhengou and Guo Zhihong.

Introduction

A premises drop optical fibre cable is the section of optical cable in the access network between the subscriber entry point and the subscriber-end connection point (for example a campus distribution frame or a building distribution frame) or the subscriber optical node; it is usually led in from outdoors and terminates indoors. At present, premises drop cables installed by different laying methods have different structural and performance requirements.

GB/Z 41287, Optical fibre telecommunication cables for use in premises cabling, is divided according to the laying method of the cable into two parts. Part 1: Optical fibre cables for duct and direct buried application, which aims to standardize the structure and performance requirements of premises drop cables laid in ducts or directly buried. Part 2: Optical fibre cables for self-supporting aerial application, which aims to standardize the structure and performance requirements of premises drop cables laid as self-supporting aerial cables.

1 Scope

This document specifies the classification, structure and materials, performance requirements and test methods of optical fibre telecommunication cables for use in premises cabling installed by self-supporting aerial laying.

This document applies to self-supporting aerial outdoor drop optical fibre cables running from the subscriber entry point to the subscriber-end node (for example a campus distribution frame or a building distribution frame) or to the subscriber optical node.

This document does not apply to ADSS and similar optical fibre cables used in high-voltage environments.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.

GB/T 6995.2 Methods for identification marking of wires and cables - Part 2: Standard colours; GB/T 7424.2-2008 Generic specification for optical fibre cables - Part 2: Basic optical cable test procedures; GB/T 9771 (all parts) Single-mode optical fibres for telecommunication; GB/T 12357.1-2015 Multimode optical fibres for telecommunication - Part 1: Sectional specification for category A1 multimode fibres; GB/T 15065 Black polyethylene plastics for wires and cables; GB/T 15972 (all parts) Specifications for optical fibre test methods; GB/T 15972.22-2008 Specifications for optical fibre test methods - Part 22: Measurement methods and test procedures for dimensions - Length.

GB/T 18380.12-2008 Tests on electric and optical fibre cables under fire conditions - Part 12: Test for vertical flame propagation for a single insulated wire or cable - Procedure for 1 kW pre-mixed flame; GB/T 18380.35-2008 Tests on electric and optical fibre cables under fire conditions - Part 35: Test for vertical flame spread of vertically-mounted bunched wires or cables - Category C; GB/T 29233-2012 Single-mode telecommunication outdoor optical fibre cables for duct, direct buried and non-self-supporting aerial application; GB/Z 41287.1-2022 Optical fibre telecommunication cables for use in premises cabling - Part 1: Optical fibre cables for duct and direct buried application.

YD/T 629.1 Monitoring method for the change of optical fibre transmission attenuation - Transmitted power monitoring method; YD/T 629.2 Monitoring method for the change of optical fibre transmission attenuation - Backscattering monitoring method; YD/T 837.2-1996 Test methods for copper-conductor polyolefin-insulated aluminium-polyethylene laminated sheathed local telecommunication cables - Part 2: Electrical test methods; YD/T 837.3-1996 idem - Part 3: Mechanical and physical test methods; YD/T 837.4-1996 idem - Part 4: Environmental test methods.

YD/T 908 Designation method for optical fibre cable types; YD/T 979 Technical requirements and test methods for optical fibre ribbons; YD/T 1113 Halogen-free low-smoke flame-retardant materials for telecommunication cables and optical fibre cables; YD/T 1258.1-2015 Indoor optical fibre cable series - Part 1: General; YD/T 1997.2-2015 Drop optical fibre cables for telecommunication - Part 2: Round cables; YD/T 2965 Characteristics of bending-loss insensitive multimode optical fibres; IEC/TR 62691:2016 Optical fibre cables - Guide to the installation of optical fibre cables (Edition 2.0).

3 Terms and definitions

For the purposes of this document, the terms and definitions given in GB/Z 41287.1-2022 apply.

4 Classification

4.1 General. In this document, types and specifications are classified and type designations are compiled in accordance with YD/T 908.

4.2 Type. The structural type, classification and code of the cable shall comply with YD/T 908.

4.3 Specifications. 4.3.1 The optical fibres in the cable shall be class B1.1, B1.3 and B6 single-mode fibres complying with GB/T 9771 (all parts), or class A1a.1a, A1a.2a, A1a.3a and A1b multimode fibres complying with GB/T 12357.1-2015, or class A1a.1b, A1a.2b and A1a.3b bending-loss insensitive multimode fibres complying with YD/T 2965. Note: B1.1 is dispersion-unshifted single-mode fibre; B1.3 is wavelength-extended dispersion-unshifted single-mode fibre; B6 is bending-loss insensitive single-mode fibre for the access network, with four subclasses B6.a1, B6.a2, B6.b2 and B6.b3; A1a is 50/125 um graded-index multimode fibre, divided by bandwidth grade into A1a.1, A1a.2 and A1a.3 and by macrobending loss grade into A1a.1a/A1a.1b, A1a.2a/A1a.2b and A1a.3a/A1a.3b, where the 'a' subclasses are ordinary multimode fibres and the 'b' subclasses are bending-loss insensitive multimode fibres; A1b is 62.5/125 um graded-index multimode fibre.

4.3.2 The fibre count of the cable should be 1, 2, 4, 6, 8, 12, 16, 24, 36 or 48. Other fibre counts agreed between supplier and purchaser may also be used.

5 Structure and materials

5.1 General. 5.1.1 The cable structure is mainly the figure-8 self-supporting type or the round self-supporting type; other suitable structures are also permitted. 5.1.2 The cable structure shall provide reliable protection to the fibres during transport, storage, installation and operation, and maintain the specified optical and transmission performance of the fibres throughout the service life of the cable.

5.2 Optical unit. 5.2.1 The cable may consist of individual fibres, fibre bundles, fibre ribbons or other suitable fibre units. 5.2.2 Individual fibres may form an optical unit in tight-buffered or loose-tube structure; fibre bundles and ribbons should use a loose-tube structure; other suitable arrangements may also be used. 5.2.3 Optical units using loose tubes or slotted cores are classed as loose-structure units; units using neither are classed as tight-structure units. Either may be used. Note: loose structure means the fibre has sufficient free space inside the optical unit. 5.2.4 Identification of optical units shall comply with 6.3.3 and 6.3.4 of GB/T 29233-2012 and colours with GB/T 6995.2. 5.2.5 Tight-buffer materials should be polyamide, polyvinyl chloride, polyester elastomer, flame-retardant polyolefin, UV-cured resin, etc. 5.2.6 Loose tubes should be made of thermoplastics such as PBT, PP or PC; composite or other suitable materials may be used. The tube may be filled with a thixotropic compound or other suitable water-blocking material.

5.3 Cable core. 5.3.1 The core may be central-tube, stranded, bundled, slotted-core or another suitable type. 5.3.2 Loose-tube units should form a central-tube or stranded core; slotted-core units should form a core of one or several stranded slotted-core elements. 5.3.3 Tight-structure units (tight-buffered fibres, coated fibres or bundles, ribbons, individual fibres) may form the core together with any strength member and any water-blocking material. 5.3.4 The slotted element should be a grooved cylinder of polyolefin plastic with a central strength member. 5.3.5 The core may be water-blocked by filling compound, water-swellable materials (water-blocking yarn, tape, etc.) or other suitable materials; these shall be odourless, non-toxic, harmless to health and compatible with the cable materials they contact.

5.4 Strength members. 5.4.1 Strength members are divided into core strength members and self-supporting strength members, selected according to the application environment to give the tensile strength needed for installation and operation. Note: the core strength member is the basic element protecting the cable; the self-supporting strength member is an additional tensile element carrying the loads of self-supporting aerial laying. 5.4.2 Core strength members may be metallic or non-metallic. 5.4.3 The self-supporting member may be the messenger of a figure-8 cable or a circumferential member around the core (or core inner sheath). Metallic messengers should be single high-strength, high-modulus galvanized steel wire or steel strand; non-metallic messengers should be round rods of non-metallic fibre; circumferential members should be aramid yarn or other suitable non-metallic material. 5.4.4 Strength members and self-supporting strength members shall comply with 6.4 of GB/T 29233-2012.

5.5 Sheath. 5.5.1 The cable covering comprises the sheath and any outer covering. 5.5.2 Surfaces shall be smooth, with no visible bubbles, pinholes or cracks on any cross-section. 5.5.3 The core sheath may include a metallic moisture barrier (complying with 6.7 of GB/T 29233-2012) and a plastic jacket of polyethylene, low-smoke zero-halogen flame-retardant polyolefin or flame-retardant polyethylene. PE shall comply with GB/T 15065, LSZH polyolefin with YD/T 1113 and flame-retardant PE with Annex C of YD/T 1997.2-2015; other materials may be used on user request provided the product meets this document. 5.5.4 Any outer covering may be a metallic or non-metallic armour with polyethylene jacket. 5.5.5 The messenger jacket and web of figure-8 cables shall use the same plastic as the core sheath; their dimensions are given by the product standard. Note: a figure-8 cable consists of the core sheath unit, a parallel messenger unit and the web connecting them. 5.5.6 Minimum thickness of any inner sheath: not less than 0.2 mm. 5.5.7 Minimum sheath thickness: not less than 0.5 mm. 5.5.8 The outer sheath should be black; on user request other colours or colour stripes may be agreed. 5.5.9 Rodent- and termite-protection structures and materials are agreed between supplier and purchaser.

5.6 Flame-retardant structure. The outer sheath of flame-retardant cables should be LSZH flame-retardant polyolefin or flame-retardant polyethylene, or another suitable material. Other components such as strength members, water-blocking fillers, fillers and tapes may be non-combustible or flame-retardant to ensure the flame-retardant performance of the cable.

5.7 Standard manufacturing length. Nominal standard manufacturing lengths should be 500 m, 1 000 m, 2 000 m and 3 000 m, with a tolerance of 0 % to +5 %. The delivery length should be the standard manufacturing length or a length agreed between supplier and purchaser.

6 Performance requirements and test methods

6.1 Optical fibre characteristics and test methods. 6.1.1 Single-mode fibre characteristics shall comply with 6.1.1 of GB/Z 41287.1-2022. 6.1.2 Multimode fibre characteristics shall comply with 6.1.2 of GB/Z 41287.1-2022. 6.1.3 Unless otherwise specified, fibre tests are carried out according to GB/T 15972 (all parts).

6.2 Tight-buffered fibre. 6.2.1 Except that no outer-diameter tolerance is required, the structure, mechanical and environmental performance of tight-buffered fibres shall comply with Annex A of YD/T 1258.1-2015. 6.2.2 Verification is by the test methods of Annex A of YD/T 1258.1-2015. 6.3 Fibre ribbon. 6.3.1 The structure, dimensions, mechanical and environmental performance of ribbons shall comply with YD/T 979. 6.3.2 Verification is by the test methods of YD/T 979.

6.4 Sheath performance. 6.4.1.1 Aluminium or steel moisture-barrier tapes and any metallic armour shall each be electrically continuous along the cable. 6.4.1.2 The peel strength between metal tape and PE jacket of a bonded sheath, and between metal tapes at the overlap, shall be not less than 1.4 N/mm; no value is required for the overlap when a filling or coating compound is used under the tape. 6.4.1.3 Mechanical and physical properties of the sheath (Table 1): tensile strength before ageing min. 10.0 MPa (LLDPE), 12.0 MPa (MDPE), 16.0 MPa (HDPE), 10.0 MPa (LSZH), 12.5 MPa (flame-retardant PE); change after ageing max. 20 % (LLDPE, MDPE), 25 % (HDPE), 20 % (LSZH and FR-PE); ageing at 100 +/- 2 C for 24 x 10 h. Elongation at break before ageing min. 350 % (PE grades), 125 % (LSZH), 300 % (FR-PE); after ageing min. 300 %, 100 %, 250 % respectively; change max. 20 %; same ageing conditions.

Table 1 continued: heat shrinkage max. 5 %, at 100 +/- 2 C (LLDPE), 115 +/- 2 C (MDPE, HDPE), 85 +/- 2 C (LSZH), 100 +/- 2 C (FR-PE), for 4 h (2 h for FR-PE); environmental stress cracking resistance (50 C, 96 h) 0/10 failures. LLDPE, MDPE, HDPE and LSZH denote linear low-density, medium-density and high-density polyethylene and low-smoke zero-halogen flame-retardant polyolefin. 6.4.2 Test methods: 6.4.2.1 electrical continuity per 4.9 of YD/T 837.2-1996; 6.4.2.2 peel strength per 4.9 of YD/T 837.3-1996; 6.4.2.3 (Table 2) tensile strength and elongation before and after ageing per 4.10 and 4.11 of YD/T 837.3-1996, heat shrinkage per 4.12 of YD/T 837.3-1996, environmental stress cracking per 4.1 of YD/T 837.4-1996.

6.5 Mechanical performance. 6.5.1 Tension. 6.5.1.1 The cable shall pass test method E1 of GB/T 7424.2-2008; figure-8 or non-round cables are wound on the drum along their short axis. The maximum allowable tension (MAT) is designed from the laying conditions (span, sag, wind, ice load, installation tension). Note: MAT is the maximum tension the cable may bear under the total theoretical load at the design meteorological conditions. Table 3: allowable short-term tensile force FST = MAT and long-term FLT = 50 % x MAT for both tight- and loose-structure cables; allowable crush FSC/FLC is 1 000 / 300 N/100 mm for tight-structure cables and 2 200 / 1 000 N/100 mm for loose-structure cables (the lower values 1 000 / 300 apply to a single sheath without inner sheath or steel moisture barrier).

6.5.1.2 Table 4, allowable changes under tension: short-term, tight-structure cable fibre strain <= 0.4 % (individual and ribbon fibres), no attenuation limit given; loose-structure cable fibre strain <= 0.3 % (individual) and <= 0.4 % (ribbon), attenuation change <= 0.15 dB (single-mode individual), <= 0.20 dB (single-mode ribbon), <= 0.2 dB (multimode individual). Long-term: fibre strain <= 0.2 % (tight, both) and <= 0.1 % individual / <= 0.2 % ribbon (loose), with no obvious additional attenuation. After unloading, tight-structure cables show no obvious residual additional attenuation; loose-structure cables show no obvious residual attenuation, residual fibre strain or residual cable strain.

6.5.2 Crush. The cable shall pass method E3 of GB/T 7424.2-2008, applied along the short axis on the core axis for figure-8 and non-round cables, with allowable crush forces per Table 3. Under long-term crush there shall be no obvious additional attenuation; under short-term crush fibres shall not break, the sheath shall not crack, and no obvious residual additional attenuation shall remain after removal. 6.5.3 Bending radius. 6.5.3.1 Minimum bending radius is expressed as a multiple of D (outer diameter of round sheath at the core) or H (short-axis height of sheath at the core): static minimum 12.5 times the cable diameter but not less than 30 mm; dynamic 25 times the diameter but not less than 60 mm; special structures per product standard or agreement. 6.5.3.2 Under dynamic bending fibres shall not break, the sheath shall not crack and no residual attenuation shall remain; under static bending no obvious additional attenuation and no sheath cracking.

6.5.4 Impact. Method E4 of GB/T 7424.2-2008, along the short axis on the core axis for figure-8 and non-round cables. Table 5: hammer mass 100 g (tight) / 450 g (loose), drop height 1 m, hammer diameter 20 +/- 1 mm, striking surface radius >= 300 mm, 3 impact points spaced >= 500 mm (tight) / >= 1 000 mm (loose), 1 impact per point. After the test the sheath shall not crack; loose-structure cables show no obvious residual additional attenuation; tight-structure cables max. 0.4 dB residual for single-mode and 0.6 dB for multimode fibres. 6.5.5 Repeated bending. Method E6; the messenger of figure-8 cables may be removed. Table 6: bending radius 25D or 25H (not less than 60 mm), 200 cycles, 20 N load (tight); 25D or 25H, 30 cycles, 100 N (loose). Acceptance as for impact.

6.5.6 Torsion. Method E7; messenger may be removed. Table 7: length 1 000 mm, 20 cycles, +/-180 degrees, 20 N (tight); 1 000 mm, 10 cycles, +/-90 degrees, 100 N (loose). The sheath shall not crack; loose-structure cables show no obvious additional attenuation at the extreme position and no residual attenuation after the test; tight-structure cables max. 0.4 dB (single-mode) and 0.6 dB (multimode) residual. 6.5.7 Coiling. Method E11 procedure 1, coiled along the short axis for figure-8 and non-round cables: mandrel diameter twice the specified static bending radius (not less than 60 mm), 10 close turns per cycle, at least 5 cycles; fibres shall not break and sheath shall not crack. 6.5.8 Sheath abrasion (on user request). Method E2A: steel needle diameter 1 mm, load 4 N, 10 cycles; fibres shall not break and the sheath shall not be perforated.

6.5.9 Mechanical test methods. Unless otherwise specified, tests follow GB/T 7424.2-2008. Monitoring wavelength is 1 550 nm for B1.1, B1.3 and B6 fibres and 1 300 nm for A1a.1a, A1a.2a, A1a.3a, A1b and A1a.1b, A1a.2b, A1a.3b fibres. Attenuation change should be measured by the transmitted power method of YD/T 629.1 with uncertainty not exceeding 0.03 dB (single-mode) and 0.12 dB (multimode); changes within these values are judged as no obvious change, and allowed changes include this uncertainty. Fibre strain should be measured by the phase-shift method of Annex C of GB/T 15972.22-2008 with uncertainty not exceeding 0.01 %; strain not greater than 0.01 % is judged as no obvious strain; other methods are allowed but the phase-shift method prevails in disputes. Cable strain measured mechanically or by sensors has an uncertainty not exceeding 0.05 %; values not above 0.05 % are judged as no obvious strain.

6.6 Environmental performance. 6.6.1 Temperature attenuation. The cable shall pass method F1 of GB/T 7424.2-2008: sample length at least 1 000 m; temperature limits per Tables 8 and 9; rate of change slow enough to avoid thermal shock; soak time t1 long enough for the whole length to reach temperature, per product standard; 2 cycles (more by agreement). Temperature range classes A to E are: A -40 to +70 C, B -40 to +60 C, C -25 to +70 C, D -25 to +60 C, E -10 to +60 C. Loose-structure cables (Table 8) have attenuation grades 0 to 3 relative to 20 C: for B1.1, B1.3, B6 fibres grade 0 no obvious additional attenuation, grade 1 <= 0.05, grade 2 <= 0.10, grade 3 <= 0.15 dB/km; for A1a, A1b fibres grade 0 none, <= 0.10, <= 0.20, <= 0.30 dB/km. Tight-structure cables (Table 9) have grades 1 to 3: <= 0.30, <= 0.40, <= 0.50 dB/km for single-mode and <= 0.50, <= 0.60, <= 0.80 dB/km for multimode fibres.

6.6.2 Low-temperature bending (loose-structure cables only, on user request): U-bend test at -20 C; sample conditioned at (-20 +/- 2) C for at least 24 h then tested immediately per method E11 procedure 2, wound along the short axis for figure-8 or non-round cables; short sample of a few metres; bending radius 15 times the cable diameter; 4 cycles; fibres shall not break and sheath shall not crack. 6.6.3 Low-temperature impact (on user request): sample conditioned at (-20 +/- 2) C for at least 24 h, then method E4 per Table 10: hammer 100 g (tight) / 450 g (loose), drop 1 m, diameter 20 +/- 1 mm, surface radius >= 300 mm, 1 impact point; fibres shall not break and sheath shall not crack.

6.6.4 Low-temperature coiling (tight-structure cables only, on user request): sample conditioned at (-15 +/- 2) C for at least 24 h, then method E11 procedure 1, wound along the short axis for figure-8 or non-round cables; short sample of a few metres; mandrel diameter twice the static bending radius (not less than 60 mm); 4 close turns per cycle; 1 cycle; fibres shall not break and sheath shall not crack. 6.6.5 Sheath integrity shall comply with 6.6.4 of GB/Z 41287.1-2022. 6.6.6 Water penetration: where required, and unless otherwise specified, the cable shall pass method F5B (filled cables) or F5C (dry water-blocked cables) of GB/T 7424.2-2008; no requirement applies to the messenger unit.

6.6.7 Environmental test methods. Unless otherwise specified, tests follow GB/T 7424.2-2008. Monitoring wavelengths are 1 550 nm for B1.1, B1.3, B6 single-mode fibres and 1 300 nm for A1a.1a, A1a.2a, A1a.3a, A1b and bending-loss insensitive A1a.1b, A1a.2b, A1a.3b multimode fibres. The change in attenuation coefficient should be measured by the backscattering method of YD/T 629.2, with uncertainty not exceeding 0.02 dB/km (single-mode) and 0.08 dB/km (multimode); changes within these values are judged as no obvious change, and allowed changes include this uncertainty.

6.7 Burning performance. Flame-retardant cables shall meet: a) flame retardancy - pass the single vertical burning test of GB/T 18380.12-2008 and, on user request, the category C bunched cable test of GB/T 18380.35-2008; b) smoke density - light transmittance not less than 50 %; c) corrosivity - pH of combustion gases not less than 4.3 and conductivity not greater than 10 uS/mm. 6.8 Environmental protection: on user request, shall comply with 6.8 of GB/Z 41287.1-2022. 6.9 Installation: cables should be installed in accordance with IEC/TR 62691:2016.