The range between the upper and lower flammable limits is referred to as what?

The range between the upper and lower flammable limits is referred to as what?

• A. Flash point
• B. Ignition temperature
• C. Flammable/explosive range
• D. Vapor density

Answer: (C)

The range between the lower and upper flammable limits is the flammable/explosive range—the concentration window of vapor in air that can support ignition. Below the lower limit the mixture is too lean to burn, and above the upper limit it’s too rich to burn. Within this window, an ignition source can cause flame or explosion, depending on confinement. Flash point, ignition temperature, and vapor density describe other properties: flash point is the temperature at which vapors will briefly ignite, ignition temperature is the minimum temperature needed to start combustion, and vapor density relates to how heavy the vapor is compared with air.

The range between the lower and upper flammable limits is the flammable/explosive range—the concentration window of vapor in air that can support ignition. Below the lower limit the mixture is too lean to burn, and above the upper limit it’s too rich to burn. Within this window, an ignition source can cause flame or explosion, depending on confinement. Flash point, ignition temperature, and vapor density describe other properties: flash point is the temperature at which vapors will briefly ignite, ignition temperature is the minimum temperature needed to start combustion, and vapor density relates to how heavy the vapor is compared with air.