Auto-Ignition Temperature (AIT) Testing

Our test method adheres to ASTM E659, and use the same quality system as our calibrated tests. 

The auto-ignition temperature (AIT) test is conducted to determine the lowest test temperature at which a substance will produce hot-flame ignition in the air at a specific atmospheric pressure, without the aid of an external energy source such as a spark or flame.

It is the lowest temperature at which a combustible mixture should be raised so that the rate of heat evolved by exothermic oxidation reaction will overbalance the rate at which heat is lost to the surroundings and cause ignition.

The test is predominantly conducted on liquids, however gases and solids are capable of full vaporisation should be tested using the method below:

Working through a range of material concentrations, the material is injected into a heated and thermally stabilised, 500 ml round bottom flask. Once an ignition temperature is observed, the flask temperature is reduced, and the material concentration is varied until an auto-ignition temperature is established.

The auto-ignition temperature is required to define the maximum permitted surface temperature of electrical and non-electrical equipment used in areas where potential testing material is present. This allows for the correct and appropriate designation of equipment based on their temperature or “T” Class.

Many products are incorrectly given an autoignition temperature based either on untrustworthy literature or on its worst-case component (component with the lowest auto-ignition temperature).

Other inert or less sensitive components within the product can greatly affect the overall auto-ignition temperature of the product. Due to a variety of chemical and physical properties, these product blends will usually produce a higher auto-ignition temperature. This makes auto ignition temperature testing a cost saving measure.