The air tightness testing process

Exova will help you achieve ongoing improvement based on practical guidance before, during and after air tightness testing.

Before the air test:
  • Pre-test inspection – our air tightness technicians will conduct an inspection of the building to be tested to point out potential problems
  • Indicative air leakage testing, of components and/or sections of the building to provide an insight into the final air permeability performance of the building
  • Identification of an air testing programme (where required) and discussion with Building Control as necessary
  • Liaison with site directly – our air tightness technicians will contact the site to arrange provisional air test dates, explain the process and preparation, confirm the plot is ready for air leakage testing and what needs to be achieved
  • Confirmation of the air permeability requirement, so we know if the test result is a pass or a fail on site and can help to address any issues
During the air test:
  • Envelope area calculations
  • Preparation of the building as required in ATTMA Technical Standards (where agreed in advance), including identification of potential air permeability problems
  • Provisional air test results available immediately, certificates can be issued on the same day if requested (although not on-site)
After the air test:
  • Diagnosis - identification of air leakage points, ideally on the day with the opportunity to resolve issues and repeat the air pressure test (where possible)
  • Smoke testing
  • Smoke pens
  • Short-form report and certificates by email

The ATTMA Scheme
In January 2015, the ATTMA Scheme for Competent Air Tightness Testing Firms and their Testers (The ATTMA Scheme) was launched. It is an industry competence scheme authorised by the DCLG and specified in Approved Document L1 & L2 of the Building Regulations. It is based on the performance criteria and knowledge requirements set out in the suite of National Occupation Standards (NOS) and under the requirements of the Minimum Technical Competence (MTC) document.

There are three levels of tester:

Level 1: Testers can test dwellings and non-dwellings up to 4000mgross envelope volume when tested as a single entity, with a single fan.

Level 2: Testers can test all buildings except large, complex and or high-rise buildings and or phased handover or zonal buildings unless part of a team managed by a Level 3 tester.

Level 3: Air tightness experts who can cover large, complex and or high-rise buildings and or phased handover or zonal compartmentalisation.
Why choose an ATTMA Registered Company?
ATTMA is approved by DCLG and are listed in the Building Regulations as an authorised Competent Persons Scheme for air tightness testing.

As an ATTMA Level 2 registered company, Exova is independently audited and certified by UKAS and certified by ATTMA with a scope covering air tightness testing to the ATTMA Technical Standards (TSL1 & TSL2) and BS EN: 13829 (2001), demonstrating knowledge and understanding, which enables us to test both commercial and domestic developments in accordance with relevant building regulations.
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