Since 2003 Building Regulations in the UK have required buildings to be tested to achieve a minimum level of airtightness. The Director of BAT has been testing buildings for Air Tightness since 2003 when the Building Regulations requirement for testing New Buildings over 1000m² was introduced to Part L2. BAT was set up by him in 2006 specifically to meet this growing requirement.

The maximum building Air Permeability allowable under Building Regulations is 10m³/hr.m² at 50 Pascals pressure.  Pressurising the building to 50 Pascals is achieved by use of door fans (or for very large buildings a vehicle mounted fan unit with it’s own generator) installed in an appropriate opening, usually a doorway. Contrary to popular belief the maximum allowable Air Permeability of 10m³/hr.m² has not been reduced by Building Regulations since it was first introduced, however building energy calculations (including SBEM for L2 and SAP for L1 buildings) routinely require targets significantly lower than this to be achieved.  Targets of 5m³/hr.m² or even an onerous 3m³/hr.m² are often being specified.

With such increasingly onerous Air Permeability targets a site inspection consultancy visit during construction can be invaluable in identifying issues threatening a successful first time Air Permeability test result, in good time for them to be appropriately addressed.

BAT have been a UKAS Accredited Laboratory for Mobile Testing since inception, with our Accreditation covering Air Permeability Testing and Sound Insulation Testing to the prevailing standards.  We consider UKAS Accreditation important to demonstrate to our customers that we provide an independently accredited, high quality service.  BAT staff have tested thousands of buildings since 2006 (both residential and commercial) and have considerable experience of the issues associated with making different construction types airtight. All our engineers are trained and registered with the Air Tightness Testing and Measurement Association (ATTMA) Competent Persons Scheme.

ATTMA has been striving to improve construction standards in respect of airtightness and introduced a competent persons scheme in 2015 to ensure that only individuals and organisations which have demonstrated appropriate competence and use calibrated equipment are able to lodge test certificates. Guidance for Builders and Contractors is available on the ATTMA Website Downloads and Links for free. The allowable temporary sealing is normally restricted to designed ventilation and trickle vents however the ATTMA Guidance document for Domestic Testing is available on the above link.