BS/EN 60079-13-2017 pdf download.Explosive atmospheres Part 13: Equipment protection by pressurized room “p” and artificially ventilated room ‘v’ (IEC 60079-13:2017).
4.2.2 ArtificIal ventilation “v”
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 safely devices (see 7.3.1).
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.
4.3 Construction
The protected room shall, at a minimum, be designed to allow pressurization or artificial
ventilation to be used 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 ensure adequate purging of dead air spaces created within the room, for example by avoiding suspended ceilings, trenches, or raised floors.
4.4 Mechanical strength
The room and any ducts and their connecting parts shall be designed to withstand the maximum pressure of the pressurization or ventilation system. This shall be verified by the design documentation or by the overpressure test of 6.4.2. National or regional building requirements may also apply.
Test for mechanical strength need not be carried out on the completed room but may instead be applied to all parts such as windows, gland plates, penetrations, doors, inlets or outlets of the room which are not made of steel or concrete but which are integral to the type of protection. In this case, the tests may be carried out on the parts themselves, appropriately mounted for the test.
4.5 Penetrations and seals
The entry of cables, electrical conduits and other penetrations into the room shall be sealed
so that the necessary pressure differential or artificial ventilation integrity is maintained. Measures shall be taken to minimize the exchange of atmosphere between the inside and the outside of the room where this may lead to another hazard, for example displacement of vapours via floor drainage facilities.
Barriers may need to be considered for certain room designs to minimize ingress or egress of gases or vapours, for example this may include liquid seals such as s-bends in drain piping.
4.6 Personnel access doors
Where protection against ingress of a flammable atmosphere is required, doors for personnel access shall be automatically self-closing, close fitting, and designed to close and latch against the normal pressure differential. Restricted access doors are not required to be self- closing.
NOTE Refer to IEC 60079-10-1 for additional guidance on doors.
4.7 Inlets and outlets
For pressurization and general artificial ventilation, the location of air inlets and outlets shall be arranged to ensure even distribution of the clean air flow to minimize pockets where gases or vapours could accumulate, taking into account the density of those gases and vapours. Verification shall be according to 6.4,4 or 7.5.3.
Where it is not possible to avoid pockets where gases and vapours can accumulate, alternative methods of detection and control shall be used.BS/EN 60079-13-2017 pdf download.