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Air Pressure Testing

posted 12 Dec 2013, 03:04 by Unknown user   [ updated 12 Dec 2013, 03:05 ]
Air pressure testing measures the air tightness of a property in compliance with Building Regulations Part L. The Air pressure testing involves raising the air pressure inside the property by 50 Pascals using a fan inserted in the entrance doorway. The rate by which the internal air pressure returns to normal is then measured which indicates how airtight the building is.

The result of the test is then incorporated into the final SAP calculation and production of the EPC for the property. Testing shows how well properties will retain heat and in turn reduce carbon emissions, making them more efficient and cheaper to run.

Do I need to have a test?

Following the changes brought in with the new Approved Document L1 (October 2010) air pressure testing now needs to be undertaken on 50% of the units in each dwelling type (or 3 tests which ever is the lesser). This is likely to increase the number of tests on smaller sites (up to 50 units) while larger sites of 150 units or more are likely to require fewer tests.

How can you achieve the best test result?

There are certain fundamental principles which, if followed, will maximise the potential for an individual property to achieve the required levels of air tightness.
  • Domestic doors and windows - good quality products, professionally installed should perform better than poor/defective products.
  • Trickle vents - are closed but not sealed during testing, so it is important they create a good seal and are not damaged, distorted or dirty.
  • Loft hatches - many of the plastic hatches used for domestic applications may distort or be ill-fitting.
  • Floor and wall junctions - gaps between the floor and skirting board in both solid and suspended floors can give rise to air leakage
    Air Pressure Testing
  • Plumbing - heating, water and waste pipes may allow air to leak around them if not tightly sealed.
  • Electrical fittings - sockets and light switches are unlikely, individually, to contribute a great deal to air leakage, but in combination their impact can add up so it is important to emphasise the importance of good workmanship behind them, especially on external/party walls.
  • Ventilation - although the grilles of mechanical ventilation, extraction, air supply/exchange can be sealed during testing, it is important to ensure that they are well fitted and that where they run through voids or risers, air does not leak around them.
All of our air tightness, air pressure and air permeability tests are carried out in accordance with ATTMA TS1 issue 2 to BS EN 13829 method B standards, and all our test engineers are trained and registered members of BINDT.

For FREE advice and to get a fast Air Tightness Testing quote please call us on 01279 873380, or email us at