Extract Testing

Building Regulations Part F - Extract Testing

Ashby Energy Assessors were one of the first to provide extract testing throughout the UK with specialist advice on achieving compliance and how best resolve any potential problems.

What is Extract Testing?

Extract flow rate testing is a post instillation test on extractor fans installed in homes and commercial buildings. There are a range of ventilation system types, each with varying required minimum flow rates to achieve as specified within Approved Document Part F.

Best way to achieve compliance

• Use the shortest possible ductwork path, utilising rigid ducting where possible to reduce resistance along the duct run. This also prevents blockages which can be caused by the grouping up of excessive flexible ductwork.
• The installation of extracts capable of exceeding the minimum required flow rate. The flow rate extractor fans are typically advertised with the flow rate the fan can achieve with little to no resistance.

Are there minimum flow rates the fans need to achieve?

Yes. Depending on the location within the dwelling, the facilities the room has and the ventilation system type the minimum required flow rate will vary.

Flow rate targets for Intermittent Extracts:

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

A higher target may be required for the kitchen if the extractor fan is away from the hob.

Flow rate targets for Continuous Extracts (Boost/High Rate):

• Utility - 8l/s
• Kitchen - 13l/s
• Family Bathrooms and En-suites - 8l/s
• Sanitary Accommodation, W/Cs - 6l/s

Continuous extracts must also satisfy a collective extract rate that is at least that of the dwelling ventilation rate which is determined by the floor area and/or number of bedrooms. 

Continuous extracts without trickle vents also require supply fans to satisfy the dwelling ventilation rate.

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, the fan may not be in a condition to test.

What is the importance of the test?

Lower air tightness test scores have placed greater importance on ensuring ventilation systems are correctly sized and installed. Extract fans remove pollutions and water vapour which could led to mould growth as well as removing odours from the property.

For more information on extract testing or the requirements regarding Building Regulation Part F please do not hesitate to contact us on 01476 870 504 or contact info@ashbyenergy.co.uk

Simple Process

We aim to keep the process as simple and un-intrusive as possible with clear up-front quotations for all work.