Telephone: 07763 385791  |  Email: james.evered@apt-solutions.co.uk


Q. Who can carry out the Air Permeability Testing?

A. BINDT (British Institute of Non-destructive Testing) registered technician.


Q. Who selects which buildings to test and when?

A. It is the responsibility of Building Control or the Approved Inspector to select which units need to be tested. You can also contact us and we will suggest what builds would be best to test and then you can pass it onto Building Control.


Q. What is the pass mark for a test?

A. The Building Regulations require that all new dwellings achieve an air permeability score of less than 10m3/hm2. That is the air leakage rate per hour per m2 of dwelling envelope area. However the SAP requirement may have a lower score.


Q. What is SAP's Design Air Permeability and why does this sometimes have different values?

A. This is the value that you are testing to, you must achieve a test result lower than this in order to pass. This is set by your SAP assessor and forms part of the SAP calculations for energy loss at the design stage. Normally the highest target that is set is 10, however if the SAP assessor has to make savings to make the dwelling pass then the value may be lower.


Q. How much does Air Tightness Test cost?

A. It depends on how many units will need to be tested that day. Normally the first test is full price and all others that day are half price. On very large sites then an individual tender can be put forward. Please use contact form to discuss your needs and we can give you a price.


Q. How long does typical domestic Air Tightness Test take?

A. This depends on the complexity and size of the dwelling but a simple small 3 bed house would take around 2-3 hours from start to finish. It can take longer if there are problems but we can be there for the whole day if needed.


Q. Will we know whether we have passed or failed at the time of testing?

A. Yes as soon as we start running the fan we can let you know within 10 minutes if it is passing or failing.


Q. How many air pressure tests can be performed on one day?

A. Depends on size/complexity of each unit but relativity simple units can be around 4 tests in a day.


Q. Do you test commercial premises?

A. Not at present. We deal with Part L1A of the Building Regulations which covers domestic dwellings; houses, flats and apartments.


Q. Do extensions need to be air pressure tested?

A. Where an extension is proposed to an existing building with a total useful floor area over 1000 sq.m. the building is to be upgraded, insofar as it is technically, functionally and economically feasible to meet the requirements of Part L. (This is to meet the requirements of Article 6 of the Energy Performance of Buildings Directive). For average dwellings, therefore, pressure testing of extensions is unlikely to be required.


Q. Will air leakage testing disrupt work on site?

A. We do our utmost to cause minimal disruption. Most of our time on site is in the setting up process. During that process other trades can carry on working. However once the test is running we ask if trades can leave for about 20 minutes. Sometimes trades can remain but it depends on what they are doing.


Q. I am building several dwellings or a block of flats do they all need testing?

A. Part L 2010 and 2013 increases the amount of testing required to 3 tests or 50% of each dwelling type, whichever is less. The criteria for defining similar dwelling types has also expanded such that there are now likely to be more tests required per development than was the case under Part L 2006.


Please note: Under Part L 2010 and 2013, plots that are not tested attract a penalty of +2.0 m3/(m2.h)@ 50 Pa in the as-built SAP, so if the target is 10 m3(h.m2)@ 50 Pa, a result of 8m3 /( h.m2) @ 50 Pa or better is needed from the tested plots to allow those units not tested to pass.


For the 2010 and 2013 Regulations the test regime / similar dwelling type groups are determined by the testing organisation in collaboration with the Building Control body. Plots are chosen in line with the ADL requirement of 50% testing to be carried out within the first 25% of each dwelling type. What determines a similar dwelling type is defined in detail in the regulations.


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Air Permeability Testing Solutions - Bowden Lodge, Oldstairs Road, Kingsdown, Kent, CT14 8EH