Auto Ignition Temperature and T-Class

The Auto Ignition Temperature of substances and the Temperature Class of Equipment are related.

The Auto Ignition Temperature of substances is the lowest temperature in which the substance spontaneously ignites in a normal atmosphere without an external source of ignition, such as a flame or spark. This temperature is required to supply the activation energy needed for combustion.

The surface of equipment, to be used in hazardous areas, may not exceed the AIT of the substance that causes the hazardous area. The following temperature classes are known:

temp class


The AIT of 1-Butanol is 343°C. Which temp class may the equipment that is placed in the hazardous area have?


The temperature class of the equipment may be T2 to T6 but not T1!

The AIT of substances and the needed Temp class of equipment are available from the substance database in Hazcalc. 

Download the information sheet here.