As part of our national service we are able to competitively price for air tightness and sound testing across the entire of the UK and have a range of clients across the whole of the UK. At the completion stage of a new build scheme we can now offer full building performance testing for building regulations Part E and Part L. This includes both sound tests to Approved Document ‘E’ and air tightness testing for Approved Document ‘L’ (Part L) compliance.
We can provide final acceptance air leakage tests to comply with Approved Document L1 of the Building Regulations for residential schemes and Approved Document L2 of the Building Regulations for commercial schemes. The testing is undertaken via one of our trusted partner companies who are all ATTMA certified or an accredited tester by iATS (Independent Airtightness Testing Scheme) both of which are acceptable to building control bodies.
The Building Regulations contain a maximum permitted threshold for the air tightness testing (air pressure, leakage tests), and the result of the test contributes towards SAP calculations. Air leakage testing default rates or sampling processes can be used, but it can be more cost-effective to carry out individual air pressure tests, the results of which can reduce the overall calculated energy consumption of a building.
All new dwellings require a design air permeability value, this is part of the SAP calculation used to determine a dwellings emission rate (DER) which determines the EPC rating necessary to achieve Part L compliance. Under the current building regulations Part L 2013 the SAP calculation is rated against a notional air tightness of 5m3/(m2.hr)@50Pa with a maximum permissible air tightness test result of 10 m3/(m2.hr)@50Pa. Therefore any dwelling with an air tightness greater than 5 will be penalised in the SAP.
To comply with Part L the measured air permeability should be at least 10 m3/(h m2), and DER and DFEE rate calculated using the measured air permeability are not worse than the TER and TFEE.
It is important to find out the design air permeability used in the SAP or SBEM calculation, if a lower than maximum air permeability has been used then this must be achieved in the Air tightness test or other areas of the building will require improvement to achieve Part L compliance.