An AOV, or Automatic Opening Vent, is a smoke ventilation system that opens vents automatically when a fire is detected. By letting smoke and heat escape from stairwells, corridors and common areas, it keeps escape routes clear for people leaving the building and helps the fire service get in safely.

Smoke detectors or the fire alarm signal a control panel, which automatically opens vents, windows or roof units to release smoke. There is usually a manual override so the fire service can control ventilation, and the system resets once the alarm is cleared. The result is a clearer, safer escape route.

AOV systems are most common in blocks of flats, multi-storey buildings and communal premises, where protected stairwells and lobbies must be kept free of smoke. If your building has shared escape routes over one or more floors, it is likely to need some form of smoke ventilation.

Smoke ventilation is required in many buildings under the Building Regulations, particularly residential blocks, and forms part of the overall fire strategy required by the Regulatory Reform (Fire Safety) Order 2005. Your fire risk assessment and building design will confirm what is needed, and we can advise.

Natural systems use vents that open to let smoke rise and escape on its own, which suits many buildings. Mechanical systems use fans, often through a smoke shaft, to extract smoke where natural ventilation is not practical, such as in taller or more complex buildings. We can advise on the right approach for yours.

As a life safety system, an AOV should be serviced regularly, usually at least once a year and often more frequently for larger or higher-risk buildings, with routine checks in between. Regular servicing makes sure the vents, actuators and controls all operate correctly when they are needed.