What is defined as the lowest temperature at which a combustible material ignites in air?

The auto ignition temperature is the minimum temperature at which a combustible material will ignite spontaneously in air without an external flame or spark. This concept is critical in fire prevention and safety, as knowing the auto ignition temperature helps firefighters and safety professionals in assessing the risks associated with various materials.

In practical terms, if a material reaches this specific temperature, it will ignite purely from the heat present in the environment, regardless of any ignition source. This characteristic is particularly important in environments where flammable substances are stored or handled, as it informs safety protocols and potential hazard assessments.

Understanding this temperature helps in determining safe storage conditions, as materials with lower auto ignition temperatures pose a greater risk in warmer environments or when heat is generated from mechanical processes.