Stairwell pressurisation


Research clearly shows that when a fire occurs in a multi-compartmented building, the smoke from the fire is a far greater hazard to the occupants than the fire itself. Smoke can kill by asphyxiation or poisoning well before the temperature of the fire or smoke causes injury. Smoke also obscures vision, preventing occupants from finding safe escape routes and hindering the fire brigade’s search and rescue operation.

A key part of fire safety measures is to pressurise areas used as escape (namely stairwells) to prevent smoke entering the area. The design of these systems is complicated, because as people enter and leave the stairwell during an emergency there is an intermittent loss of effective pressurisation. The system supply fan should have sufficient capacity to provide effective pressurisation and prevent smoke entering the stairwell. Balancing this there should also be a method of preventing over-pressurisation, which makes doors difficult to open.


The building code states that stairwell pressurisation systems should include supply air rates, required and minimum allowable maximum pressurisation and minimum air velocity through open stair doors. Multi compartment buildings in New Zealand must also comply with the Australian and New Zealand Standard AS/NZS 1668.1:1998. In the Building Code regulation AS 1851-2005 refers to the frequency of maintenance routines. It recommends that testing of stairwell pressurisation systems should be completed annually.

Airlab Solution

Airlab is an Independent Qualified Person (IQP) certified for Escape Route Pressurisation Systems under the Territorial Authorities of most regions in New Zealand, and so are both qualified and certified to test these systems.