What term is defined as a liquid having a flash point below 100 °F?

• A. Combustible liquid
• B. Flammable liquid
• C. Hazardous liquid
• D. Nonflammable liquid

Answer: (B)

Flammability is determined by how easily a liquid’s vapors can ignite, measured by the flash point—the lowest temperature at which vapors can ignite in the presence of an ignition source. When that flash point is below 100 °F, the liquid is classified as flammable. This threshold separates flammable liquids from combustible ones, which have a flash point at or above 100 °F. This classification matters for safe storage, handling, and labeling because flammable liquids pose a higher fire risk and require more stringent precautions. The term hazardous liquid is broader and not tied to this specific flash point criterion, and nonflammable simply means the liquid doesn’t ignite under typical conditions, which isn’t the same as having a defined flash point below 100 °F.