3. How is the air test conducted?
The test is a pressure test whereby fans are used to create a pressure difference between the inside and outside of the building/unit. By knowing how much air is being used to maintain this pressure it provides a comparable measure of the volume of air escaping through gaps, cracks, holes, etc. A negative or positive pressure difference can be created. The fan or fans are typically installed into a door using a ‘blower door fan’ template. The test itself only takes a few minutes but set up and preparation means that testing a typical house or flat takes 15-60 minutes and larger buildings may take 2-6 hours depending upon size and complexity. The pressure differences generated are small, so no damage will be done to the building or to occupants.