There are a lot of different official documents about the rules and regulation around fire safety and smoke ventilation, which, in turn, influence the way you should choose and install your AOVs. Building regulations are minimum standards that apply to almost all new residential and commercial buildings, and also alterations to the existing ones.

If you are planning to use an Automatic Opening Smoke Vent (AOV) System in your project, you will have to comply with the regulations mentioned below.

The Basic Requirements

Only BS EN12101 certified and CE marked smoke vents (AOVs) comply with the UK building regulations. When choosing an AOV, make sure to check for the CE marking.

Smoke Vent reguations


Fire Safety – Approved Document B

This document describes the rules and regulations regarding Fire Safety. It covers information on exactly what a building needs to be equipped with to prevent the spread of fire. As a rule of thumb, the very basic requirements for a residential building are as follows:

1: Installation of fire detection and fire alarm systems

In the terrible event that a fire does occur, it is of the utmost importance that there is an immediate detection and alarm system in place to let you know there is a problem. The quicker that action is taken, the better chance there is to prevent further damage or even catastrophe.

2: Means of escape

There should be more than one escape route, ultimately to destinations in the open air. Unfortunately, it is not always possible to have more than one escape route or to have a safe destination in open clear air. In certain situations, it is acceptable to have a single escape route leading to a place of relative safety.

How does an Automatic Opening Vent (AOV) Systems fit into it?

When there is a build-up of smoke within a building it can cause people to become disoriented and they are then unable to find their way out. The longer someone is in a smoke-filled area the larger the chance of permanent damage to the person’s airways often even loss of life. Even someone who knows the building well can become disorientated and lost within the smoke. If the building is a multi-storey premise, there is an even bigger chance of confusion.

The Automatic Opening Vent (AOV) Systems are integrated into the fire alarm system. As soon as the alarm is activated, the AOV automatically fully opens creating a “chimney effect”, which discards the existing smoke, therefore making it possible for people to find the exits and for Firefighters to extinguish the fire accordingly.

Building Regulations - Smoke Vent AOV

Smoke Control and Ventilation – Approved Document F

This document describes the requirements of the specific ventilation methods used in specific types of buildings. What type of ventilation is deemed adequate depends on the type of building, its purpose, the number of floors, how you can reach the upper floors (elevators/stairways etc) and also on the number of occupants that are regularly within the building.

The main aim of smoke ventilation and control is to avoid the build-up of smoke within the building. Having the correct number of AOVs in place (mainly above the staircases in multi-storey buildings) is a significant factor in achieving this outcome.

Conservation of Fuel and Power - Approved Document L

This is the document which governs how much heat insulation should be present within the roof opening. Smoke Vents especially should have the correct design for trapping heat and preventing it from escaping through the roof. The unit of measurement which is given to measure heat loss is called the U Value, and the lower the U Value means the less amount of heat which is being lost. In order to meet the regulations, any Smoke Vent or Roof Hatch must have a U-Value of 3.5 W/m2.K or lower.

BS EN12101 and CE Marking

Any smoke vent (AOV) which is chosen, purchased and installed in the UK needs to meet with the European Standards as set in BS EN12101 and must have the CE Marking.

One of the rules in BS EN12101 is that the vent must have an additional source of energy in case the electricity fails. Even with a heavy load of snow on top of the vent, it still needs to be able to open far enough to allow a large enough airflow to be able to extract the smoke. The CE Mark certification indicates that the AOV has passed all the tests required.

Please feel free to contact us if you require any further information in regard to AOVs and smoke vents at [email protected] or 01922 500145