Gasoline vapors form an explosive mixture in air within which range?

Gasoline vapors form an explosive mixture in air within which range?

• A. 0.5% to 2%
• B. 8% to 12%
• C. 12% to 20%
• D. 1% to 8%

Answer: (D)

Gasoline vapors ignite only when the vapor concentration in air falls within a specific flammable range. For gasoline, that window is about 1% to 8% by volume in air. Within this range there is enough vapor and enough oxygen to support combustion, so a spark or flame can ignite and propagate a flame front. If the mixture is too lean (below roughly 1%), there isn’t enough fuel to sustain ignition. If it’s too rich (above roughly 8%), there isn’t enough oxygen to support combustion. So the correct range is the 1% to 8% by volume window.

Gasoline vapors ignite only when the vapor concentration in air falls within a specific flammable range. For gasoline, that window is about 1% to 8% by volume in air. Within this range there is enough vapor and enough oxygen to support combustion, so a spark or flame can ignite and propagate a flame front. If the mixture is too lean (below roughly 1%), there isn’t enough fuel to sustain ignition. If it’s too rich (above roughly 8%), there isn’t enough oxygen to support combustion. So the correct range is the 1% to 8% by volume window.