A special kind of calorimeter device is used in order to detect the self-heating rate of a substance. The related method is called accelerating rate calorimetry (ARC). The sample is step-wise heated to an isothermal temperature using the so-called Heat-Wait-Search (HWS) mode. At each isothermal step, the rate of temperature change of the sample is monitored without input by the heaters of the calorimeter. If such a temperature increase is detected, it is described as self-heating of the sample. An exothermic decomposition reaction is detected as soon as the self-heating rate exceeds the exothermic threshold (usually 0.02 K/min).