1.1 This European Standard specifies the requirements for the construction and testing of pressurized and purged electrical apparatus and Ex components forming part of the pressurized apparatus, with type of protection p , intended for use in potentially explosive atmospheres of gas vapour and mist. 1.2 This European Standard supplements EN 50014 in so far as it applies to pressurized and purged electrical apparatus with type of protection p . 1.3 This European Standard is applicable to electrical equipment and components of Group I Category M2 and of Group IIG Category 2 using the technique of pressurize and purge. 1.4 This European Standard includes the requirements for the construction of the enclosure and its associated components, including, if any, the inlet and outlet ducts for the protective gas, and for the safety provisions and devices necessary for the type of protection pressurization p . 1.5 This European Standard specifies the requirements for pressurized enclosures with or without an internal source of release, with the exceptions given in 1.7 and 1.8. 1.6 This European Standard specifies requirements for pressurized enclosures containing an unlimited source of release of flammable gas or vapour only where the unlimited source of release is from the surface of a liquid. 1.7 This European Standard does not contain requirements for pressurized rooms or analyser houses (for which another standard is in preparation). 1.8 This European Standard does not contain the requirements for pressurized enclosures where, in a containment system with limited or