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

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

• A. Pyrophoric liquid
• B. Unstable liquid
• C. Flammable liquid
• D. Combustible liquid

Answer: (C)

The key idea here is how flash point defines flammability. The flash point is the lowest temperature at which a liquid’s vapors can ignite in air. If that temperature is below 100°F, the liquid is classified as flammable because it can form an ignitable vapor–air mixture at relatively low temperatures, posing a greater near-room-temperature fire risk. Liquids with flash points at or above 100°F are considered combustible, which means they need higher temperatures before their vapors can ignite. Pyrophoric liquids ignite spontaneously in air (not just because of a low flash point), and unstable liquids refer to different reactive hazards, not the flash-point-based classification. So a liquid with a flash point below 100°F is a flammable liquid.

The key idea here is how flash point defines flammability. The flash point is the lowest temperature at which a liquid’s vapors can ignite in air. If that temperature is below 100°F, the liquid is classified as flammable because it can form an ignitable vapor–air mixture at relatively low temperatures, posing a greater near-room-temperature fire risk. Liquids with flash points at or above 100°F are considered combustible, which means they need higher temperatures before their vapors can ignite. Pyrophoric liquids ignite spontaneously in air (not just because of a low flash point), and unstable liquids refer to different reactive hazards, not the flash-point-based classification. So a liquid with a flash point below 100°F is a flammable liquid.