Air leakage pre-completion testing for all projects from small housing developments to mixed use schemes
Part L of the Building Regulations sets the energy efficiency standards for new homes and requires that a sample of new homes on all developments is tested for air leakage (also known as air tightness, air permeability or air pressure testing).
In partnership with BSRIA we offer a complete post-completion testing service in England and Wales. BSRIA are members of ATTMA and we have the experience to help you on any project with:
- fast response, quick results - testing is arranged around your build schedule and you receive an immediate indication of test performance on site, with a full certificate/report sent electronically shortly afterwards
- expert remedial advice if your development fails any of the tests, helping you achieve compliance as quickly as possible. We will, whenever possible, undertake re-tests during the same visit to help you get the pass you need
- a complete compliance solution if you combine your air leakage testing with NHBC building control and our energy rating services. We will ensure swift communication between teams to clear outstanding technical conditions.
When do you need air leakage testing?
Testing should be carried out on completed properties. We recommend that you discuss your requirements with us at the design stage and book provisional testing date(s) at the same time so that they're incorporated into your build programme. However, as a minimum, you should book tests 6 to 8 weeks before you need to clear any relevant Building Control conditions.
What are the Part L requirements for testing?
The required rate of sample testing for Part L varies depending on the edition and is applied to groups of dwellings that are defined as similar based on specific criteria described within the Approved Document.Part L 2006 sampling ratePart L 2010 and 2013 sampling rate
No. of dwellings in dwelling type group Sampling rate 1 to 4 1 test 5 to 40 2 tests 41+ Test 5% dwellings
If using Accredited Construction Details (ACDs) then 1 test of each dwelling type may be sufficient.
3 tests of each dwelling type or 50%, whichever is less.
NB. untested plots attract a penalty of 2.0 m3/(m2.h) in the final DER calculation (a.k.a. the 'as-built SAP').
Part L 2010 significantly increased the amount of air leakage testing required and also changed the way the results are used in the as-built DER/SAP assessmentsNeed more information on Part L 2010? Visit TechZone
NHBC Air Leakage Testing Service is delivered in Partnership with BSRIA a UKAS accredited laboratory No. 1053, a member of ATTMA and an associate member of BINDT.
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Air leakage FAQs
Downloads and links
Part L compliance solution
You might also be interested in:
Technical guidance on Building Regulations