What is an AOV?

AOV is short for Automatic Opening Vent. It is a control system that ducts smoke or air that is used in smoke and natural ventilation. This control system is mostly used in the ventilation of smoke in the case of a fire. Results found after investigations into smoke inhalation prompted the changes made to building regulations.

In the case of a fire, a detector is triggered making the AOV system to open windows, actuators or vents to increasing the room’s ventilation. This clears smoke from the affected building preventing suffocation and allowing people to safely leave the building.

An automatic Opening Vent has become a part of a typical smoke ventilation system and it is usually located at the highest point of the room or escape route. It can also be placed at the top of a smoke shaft. They always work with manual control points and smoke detectors to make the ventilation system complete. An automatic Vent Control panel can also be used to control the ventilation system.

The smoke detectors are always the first ones to become operational in the event of a fire. They send automated signals to the control panel that in turn operates the AOV pushing the air upwards, venting any toxic gases and smoke. The system can either open automatically after a fire signal or be controlled through an AOV panel when fire is reported. It can also be connected to the Building Management system (BMS) for faster response and easier control.

· Protection for the stairs

A 1.5 m² AOV system is normally at the head of the staircase.

· For corridors with external walls

Natural ventilation has always proved to be the most effective and the easiest way of ventilating lobbies and corridors that are connected to an external wall.

Automatic Opening Ventilation is found to be necessary where the only exit out of the building is through a single or multiple stairs. However, it has become normal for it to be used in any kind of building.

· For enclosed Corridors

A vertical smoke shaft is found to be useful in a case whereby the corridor is not connected to any external wall. It is installed in every level of the building with natural ventilation included at the top.


When a building is designed, an Automatic Opening Vent is incorporated. This improves significantly the safety of the building and the lives of everyone in the building. AOVs come in different forms and in a wide range of variety, but the basic uses are the same.

The main functions of Automatic Opening Vents are:

· They create a smoke-free layer and this aid in firefighting.

· In case of a fire breakout, AOV lower thermal damage.

· They are used as smoke-free escape routes.

· Automatic Opening Vents reduce heat and smoke as a result of fire.

· They are helpful in prevention of flashovers and delaying fires from fully developing.

Where Automatic Opening Vents are used

AOVs are installed in the following places:

· Warehouses, Storage facilities where the point of exit is far

· Large stores, factories and markets that are covered.

· Shopping malls

· Apartments; buildings that have single stairs and are more than three floors

· Underground or covered car parks that don’t have ventilation

· Prisons

· Any building that has an atrium