MINIMUN IGNITION TEMPERATURE (LAYER)

 

[EN 50281]

 

For the determination of the minimum ignition temperature of a 5 mm dust layer (also called smoldering or glow temperature) a layer of 5 mm thickness and with a diameter of 10 cm is prepared on a heating plate.

 

Then it is exposed during 2 h to a constant elevated temperature of the plate.

 

The smoldering/glow temperature is the lowest temperature of the plate, at which the layer ignites, smolders or self-heats to a temperature of 450C (absolute) or 250C (relative) above the temperature of the plate.

 

If none of these three conditions is met during four trials of 2 h each, the result for the plate temperature used is negative and the test is carried out at high temperatures.

 

The smoldering/glow temperature can only be determined for substances that do not decompose, melt or evaporate before smoldering.

 

The smoldering temperature of a given substance depends from its physical form, e.g., crystal form, particle size or bulk density.

 

For the determination of self-ignition temperatures of layers > 5 mm, heat accumulation tests in wire baskets are carried out.