UL 60079-13-2020 pdf free download.Explosive Atmospheres – Part 13: Equipment Protection by Pressurized Room “p” and Artificially Ventilated Room “v”.
Rooms with pressurization “p” and located in a hazardous area shall be one of the following:
a) Level of protection “pb”(EPL Gb or Db). The pressurized room maintains an internal overpressurereducing the risk of ingress of an explosive atmosphere and is suitable for use in an area requiring EPL Gbor Db，permitting unprotected equipment to be installed within the pressurized room except forpressurization safety devices (see 6.3.1).
b)Level of protection “pc”(EPL Gc or Dc). The pressurized room maintains an internal overpressurereducing the risk of the ingress of an explosive atmosphere and is suitable for use in an area requiring EPLGc or Dc, permitting unprotected equipment to be installed within the pressurized room except forpressurization safety devices (see 6.3.1).
4.2.2Artificial ventilation “v”
The artificial ventilated room maintains artificial ventilation to dilute a release of flammable substance toreduce 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 offlammable substance to reduce a hazardous area such that unprotected equipment can be installed withinthe 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 artfically ventilated room except for ventilation safetydevices (see 7.3.1).
Rooms may be protected by either general or local artificial ventilation.General artificial ventilation appliesto an entire room or significant portion of a room and local artificial ventilation applies to restricted regions,for example an extraction hood.
4.3Construction
The protected room shall, at a minimum, be designed to allow pressurization or artificial ventilation to beused in accordance with Clauses 6 or 7.
NOTE The room construction requirements could be affected by the location, occupancy requirements, and functionality.
For pressurized rooms and rooms protected by artificial ventilation,provision shall be made to ensureadequate purging of dead air spaces created within the room, for example by avoiding suspended ceilings,trenches, or raised floors.UL 60079-13 pdf download.