Inertisation
If the proportion of oxygen in a mixture is
less than 10 percent by volume, then, as a
general rule, an explosive mixture does not
exist. In order to attain such a low proportion,
so-called inert gaseous substances
such as nitrogen, carbon dioxide, water
steam or halogenated hydrocarbon are
added to the mixture until the desired concentration
is obtained. If the percent by volume
of the inert gas to the flammable gas is
in the minimum ratio of 25:1,an explosive
atmosphere cannot build up, regardless of
the quantity of air added.