What is the range of an explosive range?

• A. 0 to .6
• B. More than 5 percent of
• C. .7 to 5%
• D. 0 to 1%

Answer: (C)

Explosive range is the vapor concentration in air that can ignite or explode when an ignition source is present. It’s defined by the lower explosive limit and the upper explosive limit. For many fuels encountered in this context, that window sits roughly from 0.7% up to about 5% by volume. Inside this range, ignition is possible; below it the mixture is too lean to burn, and above it it’s too rich. So 0.7% to 5% best represents the range. The other options either miss part of the window or aren’t a proper range.