arpadveress 
It can be used where equipment in a room shall be protected.
Relevant standard therefore is en/IEC 60079-13.
The artificial ventilated room maintains artificial ventilation to dilute a release of flammable substance to reduce a hazardous area inside such that the required EPL is reduced from either Gb or Gc to non-hazardous or from Gb to Gc.
Rooms with artificial ventilation “v” and located in a hazardous area shall be:
• level of protection “vc” (EPL Gc). The ventilated room maintains artificial ventilation to dilute a release of flammable substance to reduce a hazardous area such that unprotected equipment can be installed within the artificially ventilated room, and is suitable for use in an area requiring EPL Gc.
NOTE This permits equipment with a lower EPL to be installed within the artificially ventilated room except for ventilation safety devices.
Rooms may be protected by either general or local artificial ventilation. General artificial ventilation applies to an entire room or significant portion of a room and local artificial ventilation applies to restricted regions, for example an extraction hood.
Keep up good work
Arpad
