[1] This temperature is required to supply the activation energy needed for combustion.
[2] Autoignition temperatures of liquid chemicals are typically measured using a 500-millilitre (18 imp fl oz; 17 US fl oz) flask placed in a temperature-controlled oven in accordance with the procedure described in ASTM E659.
is given by the following equation:[5] where k = thermal conductivity, ρ = density, and c = specific heat capacity of the material of interest,
Temperatures vary widely in the literature and should only be used as estimates.
Factors that may cause variation include partial pressure of oxygen, altitude, humidity, and amount of time required for ignition.