By creating a difference in pressure between inside a dwelling and outside, air is dragged in/or out of the dwelling. The amount of flow that is required to generate the pressure differential determines the amount of air that is being lost through the fabric of the dwelling. This is measured in m3 per hour per m2 of building envelope area, at a pressure difference of 50 pascals.

THE PROCESS

1 A date is agreed with UK AIR TESTING (subject to weather conditions).

2 The developer sends UK AIR TESTING the building plans, (if calculating envelope and SAP calculation).

3 An engineer prior to the test calculates the surface area of the building envelopes.

4 The volume is also calculated prior to the test.

5 A UK AIR TESTING engineer will check the temperature/wind/humidity and pressure differences between inside and outside the house.

6 A test will take approx 1 hour and power must be available

7 Items will be sealed and closed i.e extractor fans.

8 The engineer will then install a UKAS accredited and tested fan to a suitable door way.

9 A range of pressures between 25 and 90 will be exerted on the dwelling.

10 The corresponding flows measured at these pressures will be recorded.

11 A report will be generated.

12 The test result will be available verbally.

13 A test certificate will be posted on receipt of payment.