Air Tightness Testing for Commercial Buildings

Air Tightness Testing for Commercial Buildings

Most Non-Domestic buildings must have an air tightness test in order to comply with part L1A and Part L2A of Building Regulations (England and Wales) and Building Standards (Section 6). 

Call us now on

01455 883 259

 and discuss your project with us, there’s no obligation and we’re happy to advise you.

Or why not complete our 'Get a quote' form


Does my New Build Commercial Property need an Air Tightness Test?

All newly constructed Non-Domestic buildings must have an air tightness test if their gross floor area is greater than 500m2. The result of this test is fed into SBEM Calculations which are required for Building Regulations compliance.

Do I have to conduct an Air Tightness Test on all my properties?

If you have multiple properties then only three tests or 50% of each building type must be tested. 

A building's 'type' can vary depending on:

  • Variations in position (end terrace or top floor flat)
  • Constructions details and size
  • Design air permeability
  • Number of significant penetrations (doors, windows, vent pipes etc). 
  • Storey height and proximity to unheated spaces (garages and stairwells).

When do I conduct the Air Tightness Test?

This depends on the type of dwelling being built. For single units, an air tightness test should be conducted at the end of construction, before final approval is given. If your project involves multiple units then testing should be carried out during the construction of the first 25% of the dwelling type. 

Your property may also require an extract flow test, which is more cost-effective to carry out at the same time. 

What does the test involve? 

The 'blower door test' is the standard test for measuring the air tightness of a building. The process involves blowing air into the house via a specially made machine mounted in the main entrance of the building (pictured below). Thermographic equipment is then used to identify any leakage paths. 

In England and Wales, a dwelling must achieve a maximum air permeability result of 10 m3/(h.m2) at 50Pa in order to pass an air-tightness test. Section 6 of The Scottish Building Regulation requires a maximum of 7 m3/hr/m2 at 50 Pascals (Pa). 

If the building fails to achieve the minimum score, the property will need to carry out corrective work in order to meet compliance. 


How do I arrange a test?

Elmhurst Energy Services would be happy to advise you of reputable air tightness assessors and companies who can carry out the test. As an energy consultancy service, we don't conduct the assessments ourselves; we use the test result as part of your building's SAP or SBEM assessment. 

Related Links

Air Tightness Testing >SBEM Calculations >

Get a quote

Please provide a few details below and we'll get back to you as quickly as possible


Elmhurst Energy Services Ltd. 16, St Johns Business Park, Lutterworth, Leicestershire, LE17 4HB

© Elmhurst Energy Services Ltd 2022. All rights reserved. Elmhurst Energy Services Limited is registered in England, Company Number: 06087105