The Building Regulations 2006 Approved Documents L1A (Domestic) and L2A (Non-Domestic) came into effect in April 2006, requiring air tightness testing to be carried out in new properties. This was followed in 2013 and 2016 with further revised documents.
Uncontrolled ventilation in dwellings and other buildings through leakage paths around doors and window frames accounts for a significant proportion of heat loss, particularly as the insulation value of walls and glazing has improved. In order to control this energy loss, the Building Regulations will regulate the overall leakage of the building structure by testing, using a pressurising / depressurising fan method.
Air leakage is quantified as air permeability, which Is the leakage of air (m3/hour) in or out of the building, per square metre of building envelope at a reference of 50 Pascals (Pa) between the inside and outside of the building.
New dwellings will be required to achieve a minimum standard of 10 m3/h.m2 at 50 Pa. However, the target air permeability set out in the SAP calculations (sometimes called Q50 / DAP figure) for a property will frequently be lower than this.
The air tightness testing of the building would be carried out in accordance with the Air Tightness Testing & Measurement Association (ATTMA), Technical Standard 1 - Measuring Air Permeability of Building Envelopes.
Acoustic Associates are competent through ATTMA to undertake domestic (Sussex and Peterborough) and non-domestic (Sussex) air tightness testing and can also issue Certification and Test Reports.