IEC 60695-2-10:2000 pdf download

IEC 60695-2-10:2000 pdf download.Fire hazard testing -Part 2-10:Glowing/hot-wire based test methods -Glow-wire apparatus and common test procedure.
The test apparatus shall be so designed that burning or glowing particles falling from the test specimen are able to f all on the layer as specified In 5.3.
Two typical examples of the test apparatus are Shown fl figures 3a and 3b.
NOTE 2 The apparatus shown in figure 3b is us.d wh.r. h.avy ft ap.cm,ns Cre being tested o where specimens are tested within the equipment.
5.2 Temperature measuring system
The temperature of the tip of the glow-wire shall be measured by a class 1 (see IEC 60584-2) mineral-Insulated metal-sheathed fine-wire thermocouple with an Insulated junction. It shall have an overall nominal diameter of 1.0 mm or 0,5 mm and wires of, for example, NICr and NIAI (type K) (see IEC 605841) suItable for continuous operation at temperatures up to 980 °C with the welded point located inside the sheath as close to the tip as possible. The sheath shall consist of a metal resistant to continuous operation at a temperature of at least 1 050 C. In case of dispute, the 0,5 mm thermocouple shall be used.
NOTE 1 A sPasm made tron a nickel-based neat-resistant alloy will satisty the above requirements,
NOTE 2 It is the intention fo a future revision of this standard that the reterence to 0,5 mm thermocouples well be withdrawn.
The glow-wire, with the thermocouple, is shown in figure 1.
The thermocouple is arranged in a pocket hole, drilled in behind the tip of the glowwire. and maintained as a close fit as shown in detail Z of figure 1. The thermal contact between the tip of the thermocouple and the end of the drilled hole shall be maintained. Care should be taken to ensure that the thermocouple is able to follow the dimensional changes of the tip of the glow-wire caused by heating.
The instrument for measuring the thermovoltages may Consist of any commercial digital thermometer with a built in reference junction.
NOTE 3 Other lemperature-measuring instrumentation may be used, but, in case at dispute, the thermocouple method muSt be used,
5.3 Speclf led layer
To evaluate the possible spread of fire, for example by burning or glowing particles falling from the test specimen, a specified layer is placed underneath the test specimen.
Unless otherwise specified, a single layer of wrapping tissue, resting on. and in close contact with, the upper surface of a piece of flat smooth wooden board, having a minimum thickness of 10 mm. is positioned at a distance of 200 mm ± 5 mm below the place where the glow-wire is applied to the test specimen. See figures 3a and 3b.
Wrapping tissue, as specified in 686 of ISO 4046 is a soft and strong, lightweight wrapping tissue of grammage between 12 g/m2 and 30 g/m2.
The wrapping tissue may be replaced by other similar materials it they have been verified as equally suitable for the purpose.
NOTE The wrapping tissu is pnmardy intended for protectiv, packaging of deiicai• articles and for gift wrapping.
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 m3 which permits observation of the test specimen. The volume of the chamber shall be such that oxygen depletion during the test does not significantly allect the result. The test specimen shall be mounted at least 100 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.