Part F - Ventilation

Building Regulations Part F - Ventilation

What is a extract or ventilation test?

Ventilation testing in dwellings includes checking trickle vents and testing extract fans to ensure compliance with 'Approved Document F of Building Regulations for England and Wales – Ventilation'.

Buildings are required to have some form of ventilation installed and these units can differ by system type, size and extract rate. Under Building Regulations Part E all extracts in a dwelling are required to be tested and must achieve a target extract rate.

Are there different target air flow rates?

The extract rates target for each unit will depend on the room usage e.g. a bathroom will have a different target rate to a utility. It is important to achieve these targets to ensure the removal of water vapour and pollutants and to stop the formation of mould and the associated health problems.

Prior to the test, please ensure all trickle vents, extract fans and cooker hoods are installed and working correctly.

Best way to achieve compliance

• Use the shortest possible ductwork path and prevent any blockage.
• The installation of appropriately powerful extracts.
• At least a 10mm undercut for each internal door.
• At least one trickle vent per window or two for double windows etc.

Are there minimum rates I need to achieve?

Yes. Depending on the location within the dwelling and the facilities the room has will affect the rate required. The targets for System 1 Extracts:

• Utility - 30l/s
• Kitchen Cooker Hood - 30l/s
• Family Bathrooms and En-suites - 15l/s
• Sanitary Accommodation, W/Cs - 6l/s

Other systems of extract exist and also have their own targets to reach, but System 1 is the most simple for compliance

What should I do?

Before the test please ensure all trickle vents/extract fans and cooker hoods are installed and are working correctly. If the product is faulty this will make testing impossible.

What is the importance of the test?

As builders become comfortable on the requirements of achieving a low air test score it has increased the pressure on ensuring the correctly sized purpose ventilation systems are installed. For example, if extracts units are placed within rooms where water vapour or pollutants are released it is important to remove them and stop the spread to the remaining house as long-term impacts could be dampness or mould which both affect a person’s health.