What’s the purpose of a stairwell AOV?

The stairwell ventilator usually serves one of two purposes; removing any smoke that gets in the stairwell of small buildings or more commonly, it provides replacement air for a lobby smoke extract system in large buildings.

If a fire breaks out, resulting in smoke getting into communal lobbies or corridors adjoining the escape stairwell, there need to be some means of removing smoke from these areas. Solutions to this include the installation of an automatic opening ventilator (AOV) or a natural/mechanical smoke shaft system.