IEC 60695-2-10:2000 pdf download-Fire hazard testing – Part 2-1 0: Glowing/hot-wire based test methods – Glow-wire apparatus and common test procedure.
5.4 Test chamber The apparatus shall be operated in a draught-free condition. This can be achieved by using a chamber with a volume of at least 0,5 m 3 which permits observation of the test specimen. The volume of the chamber shall be such that oxygen depletion during the test does not significantly affect the result. The test specimen shall be mounted at least 1 00 mm from any surface of the chamber. After each test, the chamber shall be vented to safely remove air containing degradation products. The ambient light falling on the test specimen, not counting the glow-wire, shall not exceed 20 lx and the background material shall be dark. The chamber shall be considered dark enough when the lux meter, facing towards the rear part of the chamber, is positioned in place of the test specimen and the level is less than 20 lx. 6 Verification of the apparatus 6.1 Verification of the glow-wire tip Before each series of tests, it is necessary to inspect the glow-wire tip by measuring and recording dimension “A” as shown in figure 1 , detail Z. This shall be compared with subsequent tests and when this dimension is reduced to 90 % of its initial reading then the glow-wire shall be replaced. On completion of each test, it is necessary to clean the tip, if necessary, of any residue of previously tested material, for example, by means of a wire brush and then to inspect the tip of the glow-wire for any cracks. 6.2 Verification of the temperature measuring system 6.2.1 The continuous correct performance and calibration of the temperature measuring system described in 5.2 shall be verified periodically. 6.2.2 A one-point verification of the temperature of the glow-wire can be performed using a foil of silver with a purity of at least 99,8 %, approximately 2 mm 2 and 0,06 mm thick, placed upon the upper surface of the tip of the glow-wire. The glow-wire is heated at a suitably slow heating rate, and, when the foil starts to melt, the thermometer shall indicate 960 °C ± 1 5 °C.