The span of temperatures between the Upper Explosive Limit and the Lower Explosive Limit is called what?

The span of temperatures between the Upper Explosive Limit and the Lower Explosive Limit is called what?

• A. Combustion interval
• B. Flammable range
• C. Ignition span
• D. Burn spread

Answer: (B)

Flammable range. This is the interval between the lower explosive limit (the lean side) and the upper explosive limit (the rich side) where a fuel–air mixture can ignite and sustain combustion. If the mixture is too lean, there isn’t enough fuel; if it’s too rich, there isn’t enough oxygen. Within this range, an ignition source can start burning. The other terms described don’t capture this specific concentration band: they refer to different concepts like how fast something burns or how widely a flame can spread, not the flammability limits.

Flammable range. This is the interval between the lower explosive limit (the lean side) and the upper explosive limit (the rich side) where a fuel–air mixture can ignite and sustain combustion. If the mixture is too lean, there isn’t enough fuel; if it’s too rich, there isn’t enough oxygen. Within this range, an ignition source can start burning. The other terms described don’t capture this specific concentration band: they refer to different concepts like how fast something burns or how widely a flame can spread, not the flammability limits.