Limit of explosiveness
The limiting of explosiveness of a Gaz or a vapor Combustible S are the concentration S limits of the gas (in the air) which allows that this one ignites and explodes.
The interval of explosiveness is characterized by the lower limit of explosiveness (DREGS) and the higher limit of explosiveness (Them).
Under the DREGS the mixture is too low in Combustible to start a reaction. Above the the it is the Comburant which misses.
To control the vapor and gas concentrations out of the limits of explosiveness is an essential consideration in the Civil security. The methods used to control the concentration include the use of neutral gases as the Azote or the Argon to dilute oxyhydrogen gases before returning in contact with the air. The use of resin S absorbing of gas before the discharge is also current. The gases can also be maintained above the higher limit but a brêche in the container can then make the conditions explosive.
The explosive limits of some gases and vapors are given below. The concentrations are expressed as a percentage given volume in the air.