The exothermic onset temperature for self-heating is influenced by the chemical and physical properties such as chemical-reaction kinetics, thermal conductivity and heat of reaction, as well as by other factors, including:
  • Dimensions and shape of the material - solid or powder.

  • Ambient airflow over the material.

  • Availability of oxygen within the bulk, or porosity.

  • Additives or contaminants.
Usually, the material has to be exposed to an air or ambient temperature near the onset temperature for an induction time, which is reduced with an increase in temperature.