An
explosive atmosphere
for the purposes of Directive 94/9/EC is defined as a mixture
i)
of
flammable substances
in the form of gases, vapours, mists or dusts;
ii)
with
air;
iii)
under atmospheric conditions
22
;
iv)
in which, after ignition, the combustion spreads to the entire unburned mixture (It has
to be noted that sometimes (mainly with dusts) not always the whole quantity of the
combustible material is consumed by the combustion).
An atmosphere, which could become explosive due
to local and/or operational conditions, is called a
potentially explosive atmosphere
. It is only this kind of potentially explosive atmosphere which
products falling under the Directiv
e 94/9/EC are designed for (s
ee as well chapter 4.3 ‘Risk
Assessment’).
It is important to note, that products
are
not covered by Directive 94/9/EC
where they are intended
for use in or in relation to mixtures which might potentially be explosive, but one or more of the
defining elements i) to iv) above are not present
.