Equipment with an explosion proof classification doesn’t mean the equipment will survive an explosion.Instead it means that the equipment is housed or has an enclosure which prevents an internal spark from causing a much larger explosion. In this case,the enclosure must be engineered to contain any flash or explosion. The housing on this type of equipment is generally constructed of stainless steel or cast aluminum and strong enough to contain an explosion should gas or vapor seep into the enclosure and the internal electronics ignite. The equipment must be designed so that if there if there is an internal explosion,the external surface temperature does not meet or exceed the ignition temperature of the gases in the group the equipment has been rated for.
What is the difference between Intrinsic safety and explosion proof ?
In explosion proof equipment the internals must be engineered to contain an internal explosion and avert a much larger detonation.
Intrinsically safe rating means the electronics cannot spark or create sufficient energy to ignite.
In both cases the equipment surface temperature cannot meet or ignite the gas or vapor ignition temperatures of the group it is rated in.