What defines the autoignition temperature of a flammable material?

What defines the autoignition temperature of a flammable material?

• A. The temperature at which the material will begin to burn without any other source of ignition
• B. The temperature at which the material ignites only with an external flame
• C. The temperature at which the material melts
• D. The temperature at which the material becomes resistant to ignition

Answer: (A)

Autoignition temperature is the lowest temperature at which a flammable material will ignite in air without any external ignition source. At this point, the heat released by the material’s oxidation is enough to raise its temperature to the point of ignition on its own, so no flame or spark is needed. This concept is different from the melting point, and it also isn’t about needing an external flame or spark to start combustion. In safety terms, it tells you the heat level you must avoid to prevent spontaneous ignition.

Autoignition temperature is the lowest temperature at which a flammable material will ignite in air without any external ignition source. At this point, the heat released by the material’s oxidation is enough to raise its temperature to the point of ignition on its own, so no flame or spark is needed. This concept is different from the melting point, and it also isn’t about needing an external flame or spark to start combustion. In safety terms, it tells you the heat level you must avoid to prevent spontaneous ignition.