Autoignition

temperature test

Auto ignition

temperature of

flammable gas in air

The autoignition temperature is the lowest temperature at which a flammable mixture will ignite spontaneously without the presence of an ignition source. The auto ignition temperature is used to specify safe operating, storage and handling procedures for process plant operating at elevated temperature. This test method is not designed to measure the autoignition temperature of materials which are solids or liquids at the test temperature, but it can be used to determine the auto ignition temperature of solid chemicals which readily melt and vaporise at temperatures below the test temperature. Testing is undertaken in a 500ml Erlenmeyer borosilicate flask that is uniformly heated in a purpose built furnace. A fine thermocouple inside the flask is used to monitor temperature changes that occur when a small quantity of test sample is injected into the air filled flask. The test flask temperature is progressively lowered until ignition does not occur. The test is repeated 10 times to confirm the lowest auto ignition temperature has been found.