This laboratory test is used to determine a material's capacity for oxidative self-heating. For this purpose, the material to be tested is exposed to air at elevated temperatures in a wire mesh cube. The sample, usually in the form of pellets, particles or granules, is then placed in an oven that is set to a specific temperature.
The temperature of the sample is continuously monitored for the duration of the test and a positive result is obtained if spontaneous combustion occurs or if the temperature of the sample exceeds the oven temperature by 60 °C. The UN Transport of Dangerous Goods Manual of Tests and Criteria recommends testing the sample in its standard commercial form or as received.