Low Energy House » Airtests - Air Leakage Testing

Airtight building construction and successful air tests stem from attention to detail at both the design and construction stages of the housing project

Airtests

Warm air leaking out through gaps in a dwelling’s external envelope is a major cause of heat loss and, consequently, wasted energy. Improving airtightness in dwellings reduces the uncontrolled flow of air through gaps and cracks in the fabric of houses.

Air Testing

Air testing allows the permeability or airtightness performance of the dwelling to be assessed. The technique is straightforward and can be carried out when the building envelope is complete.

Air leakage is quantified as air permeability. This is the rate of leakage (m³/h/m²) in or out of the dwelling. It is measured at a reference pressure difference of 50 Pa between inside and outside the dwelling. In the UK the Good Practice Standard for a dwelling with whole house ventilation is 4m³/h/m² and Best Practice is 3m³/h/m².

Airtests - Air Pressure Testing Equipment

To carry out the test, a fan is mounted in a temporary screen fitted into the frame of an external door opening. The fan is used to move air into or out of the building. The air leakage characteristics are determined by measuring the rates of air flow through the fan while a range of pressure differences between the inside and outside of the building are maintained.

Airtests - Air Leakage Audits

Air leakage audits identify air leakage paths in the fabric of the dwelling. While the fan is pressurising the dwelling, hand held smoke generators are used to find air leaks. The smoke is released in a small controllable trickle and clearly shows air movement. Smoke can be seen escaping through the gaps and cracks and into the outside air.

Airtests - Approved Air Pressure Testing Companies

UK Testing Companies engaged to carry out air pressure tests to comply with the Building Regulations should be members of the British Institute of Non-Destructive Testing (BINDT).

Airtests - Inform the Householder About the Airtight Barrier

Having constructed an airtight dwelling, it is important to make the householder aware of the fact.  The householder needs to know the location of the airtight barrier in order not to compromise its effectiveness when carrying out future alterations. The efficiency of the heating and ventilation provided to the house depend on the airtight barrier being maintained.

With more stringent building regulations requiring better energy efficiency, airtightness is an increasingly important issue