Purged and pressurized Purged and pressurized:
This protection technique is sometimes identified as type "p". It is designed according to NFPA 496, Standard for Purged and Pressurized Enclosures for Electrical Equipment enclosures provide a type of protection for electrical equipment that uses the technique of guarding against the ingress of the external atmosphere, which may be explosive, into an enclosure by maintaining a protective gas therein at a pressure above that of the external atmosphere.
This method is also recognized for use in Class I, Division 1 and 2 areas. The specific areas where purged and pressurized enclosures may be used and the types of electrical equipment that are contained in the enclosures are dependent on the design of the purging and pressurizing system and whether it turns off all power on loss of pressure, or just produces an alarm.
This protection technique shall be permitted for equipment in those Class I, Zone 1 or Zone 2 locations for which it is identified.
A purged or pressurized enclosure that may be suitable for Class I, Zone 2 areas.