What is the flammable range defined as?

What is the flammable range defined as?

• A. The weight of a substance compared to water
• B. The percentage of gas or vapor concentration in air
• C. The minimum temperature at which a liquid gives off vapors
• D. The minimum temperature at which a liquid fuel gives off enough vapors to form an ignitable mixture

Answer: (B)

Flammable range describes how much vapor mixed with air can ignite when an ignition source is present. It is the concentration of gas or vapor in air that can sustain combustion, usually expressed as a percent by volume and defined by the lower and upper flammable limits. Within this range, a flame can propagate; outside of it, the mixture is either too lean or too rich to burn. The correct choice captures this idea by describing the percentage of gas or vapor concentration in air. The other options refer to unrelated properties—weight relative to water, or temperature-based concepts like flash point—so they don’t define the flammable range.

Flammable range describes how much vapor mixed with air can ignite when an ignition source is present. It is the concentration of gas or vapor in air that can sustain combustion, usually expressed as a percent by volume and defined by the lower and upper flammable limits. Within this range, a flame can propagate; outside of it, the mixture is either too lean or too rich to burn.

The correct choice captures this idea by describing the percentage of gas or vapor concentration in air. The other options refer to unrelated properties—weight relative to water, or temperature-based concepts like flash point—so they don’t define the flammable range.