The NFPA defines a flammable liquid as one whose flash point does not exceed 100 F when tested by closed-cup methods.

The NFPA defines a flammable liquid as one whose flash point does not exceed 100 F when tested by closed-cup methods.

• A. 100 F
• B. 140 F
• C. 200 F
• D. 0 F

Answer: (B)

Flash point is the lowest temperature at which a liquid’s vapors can ignite in air, and using the closed-cup method gives a conservative estimate. The NFPA sets the boundary for a flammable liquid at a flash point of 100°F or below. That means liquids with flash points at or below 100°F are considered flammable, while higher flash points are not. Among the options, 100°F matches this threshold and best represents the NFPA cutoff. The higher values (140°F, 200°F) would be above the cutoff and not flammable by this standard, while 0°F is also below the cutoff and would be flammable, but the question aims to identify the NFPA boundary itself.

Flash point is the lowest temperature at which a liquid’s vapors can ignite in air, and using the closed-cup method gives a conservative estimate. The NFPA sets the boundary for a flammable liquid at a flash point of 100°F or below. That means liquids with flash points at or below 100°F are considered flammable, while higher flash points are not. Among the options, 100°F matches this threshold and best represents the NFPA cutoff. The higher values (140°F, 200°F) would be above the cutoff and not flammable by this standard, while 0°F is also below the cutoff and would be flammable, but the question aims to identify the NFPA boundary itself.