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Why EPS Group? 

Our in house team have experience in air pressure testing all types of commercial buildings, from small offices to large factories and industrial plants so you can be confident in the service and advice that you receive.

We provide instant results onsite and certificates within 24 hours. 

We’ll work with you, not against you.

Competitive Pricing

Substantial discounts available for multiple units. EPS Group are rarely beaten on price.

Diagnostics Service

Smoke/Thermal Image diagnostics available to quickly identify areas of air leakage

Fully Accredited

Be confident that you are working with a fully accredited consultancy for Air Pressure Testing.

National Coverage

EPS Group cover the entire country at competitive rates, no matter where you are based.

Multi Fan Systems

Our multi fan systems mean EPS Group have the capability to test large buildings

Flexible Appointments

Evening and weekend appointments to fit with the project schedule

Why do we undertake Commercial Air Pressure Testing?

Commercial air pressure testing of non-domestic buildings is a requirement of Part L2A of the current Building Regulations and is intended to prevent air leakage. There are certain situations where a commercial air pressure test would not be required, however it is now commonplace that non domestic buildings are tested.

Air leakage is the uncontrolled flow of air through gaps and cracks in a building fabric and is also known as infiltration or draughts.

In the UK the approved procedure for air pressure testing commercial buildings  is ATTMA TSL2 which is based on BS EN 13829:2001 ‘Thermal Performance of Buildings – Determination of Air Permeability of buildings – Fan pressurisation method’.

It is a requirement of Part L2A that any building undergoing a commercial air pressure test must achieve an air permeability result of less than or equal to 10m3/h/m2 at a pressure differential of 50 pascals.

There are many benefits to an airtight building, such as:

  • Lower Heating Costs
  • Lower Carbon Emissions
  • Smaller requirement for Heating and Ventilation systems (HVAC)
  • Better comfort for occupants

Research has shown that poor air tightness can be responsible for up to 40% of heat loss from buildings and also effect comfort levels for building occupants, hence the requirement for a test.

Organisations that provide commercial air pressure testing services should be registered as part of an approved scheme such as the Air Tightness Testing & Measurement Association (ATTMA) or the Independent Airtightness Testing Scheme (iATS).

EPS Group are members of the iATS scheme and are therefore able to guarantee that our commercial air pressure test certificates will be accepted by all Building Control Bodies no matter where you are based within the country.

Building Regulations Part L2A 2013
Commercial Air Pressure Test Internal View

Commercial Air Pressure Testing – The Process

Air Pressure Testing for commercial buildings is undertaken by means of a fan pressurisation or depressurisation technique.  In the UK the Air Permeability  is measured at a pressure differential of 50 pascals between the internal and external environment.

In order to achieve this UKAS calibrated fans are temporarily placed within the the ‘building envelope’ to provide the required flow for the air pressure test. In commercial buildings personnel doors are generally selected as the most suitable location, with 1 – 2 two fans placed in each door.

Due to the size and complexity of commercial buildings the client generally assumes the responsibility of preparing the building for test by following our simple checklist.

Some of our clients  prefer that EPS Group undertake the building preparation prior to a commercial air pressure test. If this is a service that you require please notify us when requesting a quotation.

Measurements of the building will have been taken from the relevant plans prior to our arrival onsite to allow us to calculate the building envelope area. On the day of the pressure test the technician will verify that these are correct.

All heating and ventilation systems should be switched off prior to a commercial air pressure test and all internal doors to conditioned spaces should be open. Lift doors should be closed but not sealed.

Several environmental readings such as temperature, barometric pressure and wind speed are also recorded before and after the pressure test to ensure that conditions are suitable.

During the test readings are taken at several pressure differentials, which must include 50 pascals.  The process of running a commercial pressure test generally takes around 20 – 30  minutes and results are  available instantly.

EPS Group generally allow 2-4 hours to complete each commercial air pressure test, meaning there should have plenty of time to address any unexpected problems that may arise.

Common Areas of Leakage found with Commercial Air Pressure Tests 

The image shows a sample of the common air leakage areas within commercial buildings or non dwellings, however this is not exhaustive.

There are several key principles for constructing an air tight building.

  • Identify the air barrier at an early stage of design
  • Refer to airtightness in all contracts which may impact the air barrier
  • Highlight the importance of the air tightness barrier to project teams
  • Select Airtight components
  • Check interfaces between components
  • Ensure all site workers are aware of the importance of the air barrier
  • Complete regular checks on the air barrier throughout construction.
  • Ensure that all works are complete prior to the final test

If you have any concerns prior to a commercial air pressure test, our technicians will be more than happy to discuss them.

We are also able to offer a mid-construction commercial air pressure testing service, which can eliminate problems and an early stage through the use of smoke tests or thermal imaging.

Air Pressure Testing in Commercial Buildings - Common Leakage
Thermal Image Diagnosis with a Commercial Air Pressure Test
Smoke Test with Commercial Air Pressure Test

Commercial Air Pressure Testing – Diagnostics Service

EPS Group provide an air leakage diagnostic service, which can be particularly useful when used in conjunction with a commercial air pressure test.

Sometimes it can be difficult to locate areas of air infiltration within commercial buildings due to their size and complexity.

Thermal image cameras, smoke pens and smoke machines can be used alongside our air pressure testing equipment to quickly and efficiently identify areas of air leakage, and offer advice on cost effective solutions.

Smoke Pens – Used to identify all types of leakage.  Whilst a simply tool they are still one of the most widely used and one of the most effective.

Thermal Imaging – Used to identify all types of leakage when environmental conditions are suitable. Proving there is an adequate temperature differential between the internal and external environment thermal image cameras are an ideal way of both identifying and recording gaps in the air barrier.

Smoke Machines – Used to identify large or high level leakage.  Smoke machines can be used under positive and negative building pressure and are particularly useful when trying to identify leakage at high levels or within areas that are difficult to access.

With EPS Group you can be confident in the advice that we provide.

EPS Group – The Full Package 

In addition to commercial air pressure testing EPS Group can also provide SBEM Calculations and On Construction Energy Performance Certificates, meaning your part L compliance can all be dealt with under one roof.

Using EPS Group for all Part L services can be particularly helpful if you are having difficulty achieving the required Air Permeability Result.  It may be that our SBEM Assessors  can suggest a more cost effective solutions within the calculation rather than completing remedial works.

EPS Group are able to provide the following services:

EPS Group - The Full Energy Compliance Package

Call us today to discuss your specific requirements on 0115 7270599

Watch an Air Pressure Test

Watch an air pressure test on a new dwelling taking place.  The footage shows the technician preparing the building, placing the fan system in the doorway and then running a test.  The footage is designed to give clients that have not previously experienced a test an idea of the process. For commercial air pressure tests the process is very similar however a multi fan system is generally used to pressurise or depressurise the building to 50 pascals. 


With EPS Group you can be confident that you are working with a fully accredited consultancy for Air Pressure Testing.

EPS Group, Accredited by iATS Independant Airtightness Testing Scheme
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