This standard applies to purging and pressurizing for the following: (1) Electrical equipment located in areas classified as hazardous by Article 500 or Article 505 of NFPA 70 (2) Electrical equipment containing sources of flammable vapors or gases and located in either classified or unclassified areas (3) Control rooms or buildings located in areas classified as hazardous by Article 500 or Article 505 of NFPA 70 (4) Analyzer rooms containing sources of flammable vapors or gases and located in areas classified as hazardous by Article 500 or Article 505 of NFPA 70 .This standard does not apply to electrical equipment located in: (1) Areas classified as Class I, Zone 0 (2) Areas classified as Class III (3) Areas where flammable liquids may be splashed or spilled on the electrical equipment.
ANSI/NFPA 496-2008 history
2008ANSI/NFPA 496-2008 Standard for Purged and Pressurized Enclosures for Electrical Equipment