A combustible liquid is defined as a liquid with a flash point at or above which temperature?

• A. Below 100 °F
• B. At or above 100 °F
• C. Below 50 °F
• D. Above 200 °F

Answer: (B)

A combustible liquid is defined by its flash point relative to a specific threshold used to separate easier-to-ignite liquids from less volatile ones. The flash point is the lowest temperature at which a liquid’s vapors can form an ignitable mixture in air. For classification purposes, 100 °F is the cutoff: liquids with a flash point at or above 100 °F are considered combustible, while those below 100 °F are flammable. This distinction reflects how easily vapors can ignite under typical conditions; higher flash points mean vapors aren’t readily produced at ordinary temperatures, reducing the immediate fire risk. For example, gasoline has a flash point well below 100 °F, so it’s flammable, whereas diesel or kerosene have flash points at or above 100 °F and are labeled combustible. The other temperature options don’t match the established 100 °F boundary.