Ignition Studies. Part 7. The Determination of Autoignition Temperatures of Hydrocarbon Fuels

Autoignition of combustible materials, particularly hydrocarbon fuels, play an important role in the fire hazard in the storage and handling of these materials. The minimum autoignition or spontaneous ignition temperature of a given fuel is an important flammability property of the material, but its experimentally determined value is markedly dependent on the method and apparatus employed for its determination. Some of the complex phenomena associated with autoignition, such as cool flames, zones of nonignition, multiple ignition, ignition delay, and hot-surface ignition, are defined and discussed. The numerous experimental and other factors which may influence autoignition temperatures are discussed, and their relations to autoignition phenomena are described. Some of the factors are chemical structure and composition, fuel-air ratio, concentration of oxygen, surface-volume ratio, geometry of the containing vessel, and pressure.