What term is used interchangeably with flammability range?

• A. Ignition limit
• B. Autoignition temperature
• C. Explosive limit
• D. Flash point

Answer: (C)

Flammability range is the fuel-air concentration window where a mixture can ignite or explode if an ignition source is present. This range is defined by lower and upper limits. The term used interchangeably for that same concept is explosive limits, which captures the same idea of the conditions under which combustion can occur. Outside this range, the mixture is either too lean or too rich to sustain ignition. Autoignition temperature refers to self-ignition without a flame, and flash point relates to vapor ignition at a surface temperature, not the concentration band. Ignition limit can be used in some contexts, but explosive limits is the standard term for the flammability range.