Air Tightness Testing
Air tightness testing, also referred to as air leakage, air infiltration, or air permeability testing, measures the cubic meters of air leakage per hour per square meter of the building’s exterior surface area (m³/hr.m²) in compliance with Part L of the Building Regulations.
Air leakage happens through gaps and cracks in the building’s envelope, allowing heat to escape, which increases heating costs and CO2 emissions. To mitigate these issues, Part L of the Building Regulations mandates that a representative sample of all new-build domestic dwellings undergo air leakage testing. This ensures buildings are energy efficient and environmentally friendly.
All of our tests are conducted in accordance with ATTMA TSL1 (for domestic buildings) and our engineers are fully trained and registered members of ATTMA. We also ensure that all of our equipment is UKAS calibrated to ensure the most accurate and reliable results
Air tightness testing is a crucial but often overlooked aspect of constructing new houses. It is applicable to nearly all new build dwellings, and obtaining a certificate is essential for building control approval. By ensuring compliance with these standards, we help ensure that buildings are energy efficient and meet regulatory requirements.
We ensure that all work is performed at your convenience, and upon completion, we strive to provide you with a certificate as quickly as possible.
If you require air tightness testing or related services, such as building envelope consultancy, you’ve come to the right place. Not sure which services you need? Feel free to explore our offerings or reach out to us for guidance. We take pride in providing a personalized service to all our clients, ensuring some of the highest levels of expertise available. If you’re visiting this page, you might also benefit from our other services.
What is An Air Tightness Test?
To carry out an air tightness test, we require access to an unoccupied dwelling. We install a large fan within an expandable door frame, typically positioned in an exterior door, usually the front door. During the test, all other external doors and windows are closed, and all internal doors are left open.
The fan is then used to depressurize the house to a pressure of at least -50Pa, though a pressurization test can also be performed. An anemometer measures the internal pressure, external pressure, and the effort exerted by the fan to achieve the pressure difference. Ten readings are taken at various pressures, and factors such as barometric pressure and temperature are input into specialized software to calculate air leakage.
The result is expressed as cubic meters of air lost per hour per square meter of the building envelope, which includes the floor area, wall area, and roof area.
Do I Need An Air Tightness Test?
According to Building Regulations Approved Document L, an air tightness test is required if you are:
• Constructing any new residential dwellings
• Constructing any new commercial spaces
Air tightness tests are not required for:
• Conversion projects
• Existing dwellings
• Extensions
However, we highly recommend that anyone involved in building works or anyone who owns a house or flat consider having an air tightness test. Identifying and sealing areas of air leakage can significantly reduce your heating bills, resulting in substantial long-term savings.
When Do I Need An Air Tightness Test?
Testing is usually conducted after the second fix stage. At this point, all major penetrations to walls and floors should be completed. Additionally, the following conditions must be met:
• All service penetrations must be sealed.
• Trickle vents should be installed.
• Loft access hatch must be in place.
• Plumbing should be complete with water in the traps.
• Seals need to be fitted on external doors.
• Electrical outlets should be fitted.
Ensuring these requirements are met will help achieve accurate and effective air tightness testing results.
Testing For Air Tightness Is Important
Conducting air tightness testing is not only a legal requirement but also ensures that dwellings are suitable for occupancy. An air tightness test indicates the extent of air leakage and, consequently, how much heat escapes from a specific dwelling. Neglecting air leakage can lead to several issues, including:
Dampness and rising damp
• Excessive heat loss
• Increased heating and energy bills
• Drafts
• Reduced comfort for residents
For landlords and house builders, these issues can result in unsatisfactory living conditions for tenants and residents. For developers, addressing these problems can be crucial for the successful sale or rental of a property.
Non-compliance with Part L1A of the Building Regulations can result in substantial fines and potential legal action. Therefore, it is essential to meet all standards to obtain the necessary pass certificate for the property.