Escape route pressurisation systems Inspection for BWoF
Escape route pressurisation system needs ongoing inspection to comply with the requirements of building WoF, wish to reduce cost on this inspection?
A pressurisation system is meant to prevent smoke from escaping through closed doors into stairs by bringing clean air into the stairwell. The reason for this is to have the highest pressure in the stairwell and reducing pressure in the accommodation area to enable pedestrian escaping route and firefighting access.
Study shows that when a fire occurs in a multi-storey building, the smoke from the fire is a bigger hazard to the occupants than the fire itself. Smoke can kill by asphyxiation or contaminating well before the temperature of the fire or smoke causes injury. Smoke also obscures vision, preventing occupants from finding safe escaping routes and hindering the fire brigade’s rescue operation.
An essential part of fire safety measures is to pressurise areas used as an escape (such as stairwells) to prevent smoke flow into the area. The design of these procedures is complex because as individuals enter and leave the stairwell during a crisis there is an occasional loss of effective pressurisation.
Installed system’s supply fan should have adequate capacity to deliver effective pressurisation and avert smoke from entering the stairwell. Assessing this there should also be a method of preventing over-pressurisation, which makes doors challenging to open.
Maintenance & Testing process (performing standards: AS/NZS 1668 & AS 1851 etc.)
According to building code, the stairwell pressurisation systems should comprise of supply air rates required, minimum air velocity through open stair doors and minimum allowable maximum pressurisation. Multi-storey buildings in New Zealand must also comply with AS/NZS 1668.1 In the Building Code regulation AS 1851-2005 or AS 1851-2012 refers to the frequency of maintenance routines. It urges that testing of stairwell pressurisation systems should be completed every year.