Air Tightness Testing shows how airtight a building is. The more airtight a building is the less heat energy can escape. A building’s SAP calculations will normally assume a certain level of air tightness in order to achieve a ‘pass’.
An air test is conducted by temporarily installing a large fan into an external doorway of a dwelling and either blowing air into, or sucking air out of the building. The fan is set to a series of different fan speeds to show how much air can enter or escape the building, thus showing how airtight the building is. The result (q50) is measured in m³/hour/m² surface area, (or n50 for Passivhaus, ACH – Air Changes per Hour).
The maximum q50 allowed in a SAP calculation is 10.0, although a result of 5.0 or less is typically achieved.
*Air Tightness Testing is sometimes referred to as Air Permeability Testing or Air Pressure Testing.