Registered Air Tightness Testers - United Kingdom

ATTMA Members are registered & audited air tightness testers which are independently audited and certified, with a scope covering air tightness testing to the ATTMA Technical Standards (TSL1 &/or TSL2) and BS EN:13829 (2001). This allows ATTMA member companies to demonstrate knowledge and understanding, enabling the testers to test both commercial and domestic developments in accordance with relevant building regulations.


ATTMA is approved by Governments in England, Northern Ireland, Scotland and Wales. ATTMA is listed in the relevant Building Regulations as an authorised competent persons scheme (CPS) for the air tightness testing industry.

Want to become an ATTMA member?

Simply head over to the Entry Requirements page, or straight to the training page to get your membership started. If you’re already an air tester and have the relevant entry requirements, head onto the Apply page to submit your application.

The List of ATTMA Members is shown below:

EA Calculator OnlyAuthorised to carry out Envelope Area and Volume calculations but is not authorised to test
Level 1ATTMA Registered Air tightness testers able to test dwellings and non-dwellings up to 4000m³ gross envelope volume, tested as a single entity with a single blower door fan.
Level 2ATTMA Registered Air tightness testers able to test both Level 1 and large buildings up to 80,000m2 external envelope area and/or up to 15 storeys tall. Level 2 testers are able to test buildings defined in Level 1.NOTE – All Level 2 testing companies are required to have at least one candidate that has the ‘+EA’ level.
Level 3ATTMA Registered Testers who have been assessed for a higher level of expertise can test Large, Complicated and High Rise (LCHR), phased and zonal hand-over buildings. Level 3 testers are able to test buildings as defined in Level 1 and 2.   *Presently, Level 3 is not enforced and therefore Level 2 testers are authorised to carry out Level 3 tests. Tests with a total surface area greater than 80,000m2 must be witnessed by an ATTMA authorised auditor*
SuspendedTesters who have been temporarily removed from the scheme for failure to comply with the scheme rules or companies that have failed to pay the scheme fees. These companies are NOT currently authorised to test under the ATTMA scheme.
RemovedTesters have been removed from the scheme
WithdrawnTesters have voluntarily withdrawn from the scheme
EATesters with EA are competent to carry out envelope area calculations to Level 2 or 3 on behalf of their business. Companies cannot operate at Level 2 or 3 without either an EA Calculator or an engineer with EA attached to their status.
PHATTMA members who are authorised to carry out testing for Passivhaus Buildings. Members who carry out Passivhaus tests follow the ATTMA / Passivhaus Trust joint standard TSL4.
Company Office Country Tester ATTMA No. Level 1 Level 2 EA PH Status

Any queries regarding current membership status should be directed to Barry Cope (ATTMA Scheme Manager)