GB/T 18380.34-2022 Tests on electric and optical fibre cables under fire conditions—Part 34:Test for vertical flame spread of vertically-mounted bunched wires or cables—Category B

Scope

This document describes the Class B test method used to evaluate the ability of vertically installed bundled wires, cables, or optical cables to suppress the vertical spread of flames under specified conditions. This document applies to cable and optical cable samples installed on a test steel ladder, with the total nominal volume of non-metallic materials contained in the samples being 3.5 L/m. The fire supply time is 40 minutes. The cables and optical cables are installed in front of the steel ladder. Class B is used to evaluate cases with a moderate volume of non-metallic materials. This test is used for type approval testing. Requirements for selecting cables and optical cables for testing are provided in Appendix A. The extent of damage to the cable and optical cable samples is used to measure the spread of flames. This test procedure can be used to verify the ability of cables and optical cables to suppress the spread of flames. Recommended performance requirements are given in Appendix B. Note: In this document, the term "wires and cables" includes all metallic conductor insulated cables used for power or signal transmission.

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