Autoignition temperature, also called self-ignition temperature or spontaneous ignition temperature, is a safety parameter for combustible substances. It represents the lowest temperature at which a given material will spontaneously ignite in a normal atmosphere without the need for an external ignition source like a spark or flame. At this specific temperature, the chemical reactions leading to combustion are initiated solely by the heat energy present in the environment. This property is distinct from the flash point, which is the lowest temperature at which a liquid gives off enough flammable vapors to ignite when an external ignition source is present. Understanding a substance's autoignition temperature is needed for ensuring safety in industries that handle flammable materials, as it guides the design of storage facilities, transportation protocols, and industrial processes to prevent accidental fires and explosions. Factors such as pressure, oxygen concentration, the presence of impurities, and even the size and shape of the container can influence the observed autoignition temperature.
