In the case of a fire within a building, more than 90% of fatalities are caused by smoke poisoning.
Smoke ventilation devices allow for the life-threatening smoke to be released into the open or to dilute
its concentration. The danger is therefore reduced before smoke spreads through a building and escape
routes like halls and staircases become impassable.
Upon smoke detection, the vents will be automatically opened by electric motor drives. Automatic Opening Vents (AOV) are located in positions
specified in BS5588 and Approved document B of the Building Regulations. Rising smoke, toxic gases and
heat is drawn off into the open through these smoke vents, so that escape and rescue routes remain
passable. To achieve the effect of rising thermal current, it is often necessary to provide fresh air
openings in the lower part of the building. The timing of the opening of all of the vents is of great
importance in order to enable people to escape quickly. Therefore, the use of automatic smoke alarms is
to be highly recommended in addition to manual alarm triggers.
As well as smoke vents shown above, it is necessary to provide
automatic opening vents to the top of escape stairs and lobbies, which constitute escape routes.
Automatic
opening devices can be fitted to windows, roof-lights or doors. These devices will be linked to a central
control panel, complete with a battery backup system in case of mains failure. This control panel can then
be triggered from either manual override switches local to the ventilator and the ground floor,
by dedicated smoke detectors, or by interfacing with a third party smoke detection/fire alarm system.
A smoke ventilation system can be also used for daily natural ventilation.
Smoke Ventilation Systems
Natural Ventilation Systems