Tests on electric and optical fibre cables under fire conditions - Part 3-25: Test for vertical flame spread of vertically-mounted bunched wires or cables - Category D
IEC 60332-2-25:2018 covers category D for methods of test for the assessment of vertical flame spread of vertically mounted bunched wires or cables, electrical or optical, under defined conditions. This document relates only to small cables of overall diameter 12 mm or smaller and cross-section of 35 mm2 or smaller installed on the test ladder to achieve a nominal total volume of non-metallic material of 0,5 l/m of test sample. The flame application time is 20 min. The method of mounting uses the front of the standard ladder in touching formation only. The category is intended for use with small cables where very low volumes of non-metallic material are required to be evaluated. The test is intended for type approval testing. The requirements for the selection of cables for testing are given in Annex A. The flame spread is measured as the extent of damage of the cable sample. This procedure can be used to demonstrate the cable’s ability to limit flame spread. A recommended performance requirement is given in Annex B. This second edition cancels and replaces the first edition published in 2000 and Amendment 1:2008. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) all pre-existing categories of test have been retained and updated;
b) a new category (category D) has been added to cater for testing at very low non-metallic volumes.
It has the status of a group safety publication in accordance with IEC Guide 104.