In the event of a fire, smoke detectors instruct AOVs to open, allowing cool air into the building and hot air and smoke to escape. This results in improved conditions for the occupants to escape and for fire fighters to enter.
In the absence of a method of smoke ventilation, smoke fills the room being drawn back down from the ceiling by convection as temperatures rise, leading to potential – and particularly dangerous – ‘flashover’. This is the stage of a fire whereby a room or other confined area becomes so heated that the flames flash over and through the vapours being produced by heated combustible contents in the space.
The specific design of an effective and safe AOV smoke ventilation system requires specialist involvement, perhaps by the mechanical and electrical consultant, and may well form part of a fire engineering solution.