Learn how to pass part F ventilation testing first time with this description of requirements and bullet point action list.

We have found from our experience that a great deal of extract fans are not performing as they should be, and therefore fail the ventilation tests (approximately 60-70% fail). This figure sounds a bit daunting, however with good advice from specialists like ourselves and a well-thought-out plan, passing first time should be no problem.  

Failing a Part F ventilation test post-installation can prove very costly. It can cause significant delays in completion, not to mention the additional costs of remedial work and re-test fees.

What is Part F?

Part F of the building regulations provide rules and guidance relating to ventilation standards in both domestic and non-domestic new-build properties. These rules are in place to ensure good air quality and prevent condensation which can lead to black mould, which can have a negative effect on the occupant’s health. So, it is very important to comply with the rules and regulations set out in Part F.

How/why do you test?

An experienced Part F tester will test every extract vent within a property using a specialist piece of equipment called a balometer. It is a quick process, with results being calculated in a matter of seconds.

As for why we test, it is a legal requirement to test ventilation systems in all new build developments. Testing is usually requested by building control bodies. During testing we need to identify whether the extract fans are performing as they should be. Extract fans will come with performance figures showing airflow in litres per second. However, in reality, once installed most fans do not perform to their rating. This can be down to a number of factors.

What if it fails?

As stated previously, lots of ventilation systems, unfortunately, do fail. The options for the client at this point are to either fix any ducting or installation issues, replace the fans with higher-quality units, or both. Which can prove to be quite costly. Then you will need to book and pay for a re-test. So, it is better, if you can, to get good advice at the planning stage and execute a good plan so that you have the best possible chance to pass first time.

How do I avoid failure?

The most common areas in which ventilation systems fail are to do with poor ductwork design or installation. Bad installation can be where flexible ducts have been kinked or squashed to fit into a space that is too small or made to route around obstacles or sharp corners.

Another significant factor is the length of the duct run from inside to out. Any length of duct run will negatively influence how the extract fan is working. Any duct run over 1.5 metres will significantly impair performance.

Unless you are ducting directly through a wall, then most axial fans will not be powerful enough to effectively extract the required amount of air. Some good alternatives are centrifugal fans or inline fans, which are much more effective with long duct runs.

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