A potentially explosive atmosphere exists when a mixture of air, gases, vapours, mists or dust combine in a way that can ignite under certain operating conditions. In this kind of atmosphere, special attention should be given to the equipment and protective systems that are being used for operational purposes as they might cause an explosion through friction, hot surfaces and many other methods.
Equipment and protective systems used in explosive atmospheres should be assessed through Ignition Hazard Assessment (IHA). They must fulfill the essential health and safety requirements, which implies that they shall be assessed according to their ability to prevent them from becoming ignition sources and their ability to protect against the consequence of explosion.