scope:

This report defines the conditions in which an electrical apparatus liable to cause an ignition may be used in a room or building situated where flammable gases or vapours may be present, the ingress of these gases or vapours into the room being prevented by maintaining inside it a protective gas at a higher pressure than that of the outside atmosphere. This report includes recommendations for the construction, equipping and operation of rooms or buildings and their associated parts such as inlet and exhaust ducts for the protective gas, and auxiliary control devices necessary for the satisfactory production and maintenance of the overpressure. It also recommends the tests necessary to show that the installation conforms to these recommendations, and the marking to be placed on the rooms or buildings. This report concerns only rooms or buildings in the interior of which there is no internal release (actual or potential) of flammable gases or vapours.