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What Are AOV's?

AOV's, or Automatic Opening Vents, are rooflights which have been designed to reduce smoke buildup and therefore provide a safer escape route for the buildings occupants.
In the even of a fire smoke detectors instruct AOVs to open which allows cool air into the building and allow hot air and smoke to escape, resulting 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.

Smoke Vent Opening

The information within this website is to be used as a guide only and is subject to change without prior notice. Whilst we endeavour to keep the information up-to-date and correct, we make no representations or warranties of any kind about the accuracy or suitability of the information provided. If you would like assistance at any time, please don't hesitate to call us on 01276 451555 or you may e-mail us at To see the full range of rooflights available including the smoke vents listed on this website, please visit our main rooflight website at