Basic Tanker Operations Practice Test

Autoignition temperature is the temperature at which a material will ignite on its own, without any external ignition source. At that point, the heat produced by internal oxidation is enough to sustain ignition, so no external flame or spark is required. Saying the external ignition source exists but is undetectable contradicts the idea of self-ignition, since ignition occurs without any external energy input. External ignition can trigger ignition at lower temperatures, but autoignition means no external source is needed.