Explosive Limit

The Explosive Limits refer to the conditions under which a mixture of a flammable material and air may catch fire or explode. If the percentage of flammable material in the air is between the minimum and maximum limits, the presence of a flame or a source of ignition is likely to lead to rapid combustion or explosion.

Explosive limits for many materials are in the range 2 - 10%, but for some materials the limits are much wider. Ether (diethyl ether) for example, has flammable limits of 1.7 - 48%, which is an unusually wide range. This, coupled with the low boiling point of ether (34.6°C) and high vapour pressure at room temperature (400 mm Hg at 18°C) means that it is easy to create a potentially explosive mixture of ether in air, and renders this compound an extreme fire hazard.

The material for which explosive limits are quoted may be a flammable liquid, such as ether or methanol, or a powder or dust such as flour or grain dust.

Explosive limits are also sometimes refered to as Flammable limits.