What Are Automatic Opening Vents?
Automatic opening vents (AOVs) are purpose-designed smoke and heat exhaust ventilators installed in roofs, walls, or high-level positions in buildings. They remain closed during normal operation and open automatically when triggered by a smoke detector signal via a dedicated control panel. Their primary purpose is to maintain tenable conditions in escape routes during a fire.
AOV Roof Vents
The most common type in UK residential buildings. Installed at the head of a stairwell or in the roof of an escape corridor, roof vents open upwards to allow hot smoke and gases to escape by natural buoyancy. The Ventec OSTRO is a BS EN 12101-2 certified roof vent with 140° opening, available in standard (1,100 × 1,100 mm) and large (1,100 × 1,500 mm) sizes, held in stock for next day delivery.
Smoke Louvres
Smoke louvres are installed in walls or facades and are particularly suited to corridor smoke ventilation and naturally ventilated car parks. They provide a large free area in a slimline profile and are compatible with standard 24 V DC actuator systems.
AOV Windows
In some buildings, high-level windows are used as the smoke ventilation aperture, fitted with chain or rack-and-pinion actuators. To be compliant, the window and actuator must be tested together as a system to BS EN 12101-2 — using a non-certified actuator on a window does not create a compliant installation.
Smoke Dampers
In ducted systems and pressurisation arrangements, smoke dampers control the flow of smoke through the building. They must comply with BS EN 12101-8 and are used in conjunction with AOV vents and control panels in more complex building arrangements.
BS EN 12101-2 Certification
All smoke and heat exhaust ventilators installed in UK buildings must be certified to BS EN 12101-2. Certification requires the product to have been independently tested for performance over thousands of cycles, temperature resilience at both high and low extremes, and minimum opening area. Following Brexit, UKCA marking applies to products sold in Great Britain.
24 V DC Operation
UK AOV systems operate on 24 V DC, supplied by the AOV control panel and backed by a battery backup unit (BBU). This ensures that vents can be opened even during a mains power failure — a mandatory requirement under BS EN 12101-10.
AOV Direct stocks BS EN 12101-2 certified roof vents, louvres, and windows for next day delivery. Call 01202 725 677 for technical advice.
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Our engineers are available to advise on compliance and product selection.