Type Y-Purge: Type Y purging reduces the classification within the protected enclosure from Division 1 and / or Zone 1 to Division 2 and / or Zone 2. All equipment in the protected enclosure shall be approved for Division 2 and / or Zone 2 locations. Failure to maintain pressure within the protected enclosure shall be detected by an alarm or indicator. The dilution purge time can be a manual operation and once the enclosure has been purged of ignitable or flammable concentrations, only positive pressure is required to be maintained within the enclosure and it is not necessary to remove power from the protected equipment upon the loss of purge pressure.

Type X-Purge: Type X purging reduces the classification within the protected enclosure from Division 1 and / or Zone 1 to nonhazardous. Failure to maintain pressure within the protected enclosure and / or adequate exhaust flow from enclosure vent shall be detected by an alarm or indicator. The dilution purge time shall be an automatically controlled operation and once the enclosure has been purged of ignitable or flammable concentrations, only positive pressure and adequate exhaust flow from enclosure vent are required to be maintained within the protected enclosure. However, it is necessary to remove power from the protected equipment upon the loss of purge pressure and / or inadequate exhaust flow from enclosure vent.