With an industry-leading reputation, unrivalled experience and nationwide coverage, and a dedicated in-house site services team, your air tightness requirements are in safe hands. One of our founder services back in 2006, we take immense pride in our Air Testing service, from guidance and support at initial enquiry, to mid-build site audits and pre-tests to ensure you’re ready for the final test. Our team of engineers aren’t simply just air testers that turn up, test and go, our team will guide, support, consult and above all, care about your building project and how it performs.
We pride ourselves on making sure your building project not only achieves compliance, but goes above and beyond compliance and minimises its heat loss as much as possible, ensuring more occupancy comfort and lower heating bills. Please refer to some of our case studies here.
What is Air Tightness Testing?
Air tightness testing is a recognised method of measuring the extent to which air is lost through leaks in the building fabric. Air leakage is the uncontrolled flow of air through gaps and cracks in a buildings fabric (often referred to as infiltration and draughts) and not ventilation, which is the controlled flow of air in and out of the building.
Essentially, a more air-tight building translates to better energy efficiency, lower heating and cooling costs and a much more comfortable living, working or storage environment. To view the full benefits of air tightness testing please click here.
How is Air Tightness Measured?
Air tightness is measured by calculating the rate of air leakage per square meter of the building’s external envelope per hour, under a pressure difference of 50 Pascals. This artificially induced pressure difference simulates higher wind conditions, helping to assess the integrity of the building’s air tightness layer. The rate of air leakage is expressed as Xm³/hr/m²@50Pa, a standard measurement defined by UK Building Regulations.
Alternatively, the rate at which the building’s air volume changes per hour at 50 Pa is another measurement method. This is noted as Xach/hr@50Pa and is the preferred metric used in Passivhaus air test certification.
The most common way to conduct these measurements is through a ‘blower door’ test. A membrane frame is installed in a doorway, and a large fan is positioned within the membrane. The fan blows air into the building, and the air flow is then measured.
To generate a controlled pressure difference, a calibrated fan is placed within the building’s external envelope. This fan either pushes air into or extracts it from the property. Calibrated equipment is used by the air tightness tester to measure the airflow, providing accurate readings of the building’s air tightness.
Does your project need an air tightness test?
The air tightness test, also known as air permeability test, air leakage test, air pressure test, or just simply Air test, is a mandatory requirement of the latest Part L 2022 Building Regulations.
Applying to ALL newly built dwellings, new commercial buildings over 500m2 and commercial extensions with a floor area greater than 25% of the current building, the air tightness test is a crucial part of how a building fabric performs and an integral part of the as built SAP, EPC and the final sign off process.
Approved Document L: Changes and Impact on Air Tightness
In June 2022, a revised version of Approved Document L came into effect, introducing important updates to energy efficiency standards for buildings in the UK. The document is split into two volumes:
These revisions are designed to achieve a 31% reduction in carbon emissions from new buildings as part of the transition towards the Future Homes Standard in 2025. Several areas, such as insulation, fuel types, and air tightness, have been significantly impacted by these changes.
Key Changes for Air Tightness Testing:
Air Permeability Targets and Testing
The specific air permeability target for each property is calculated based on the design rate allowed for in the SAP calculation. It is essential to know this figure from the beginning of the project to ensure compliance with the air tightness requirements.
Testing and Competency Requirements
To comply with Part L, testing must be conducted by a competent person. Our team of experienced test engineers are all registered with the ATTMA (Air Tightness Testing & Measurement Association) competent person scheme, which is referenced in Part L, ensuring that your air tightness tests are carried out to the highest standard.
By adhering to these new regulations, you not only contribute to the UK's long-term sustainability goals but also improve the energy performance of your buildings, resulting in lower energy costs and better overall building quality. For more information, request a no obligation quotation, or to book an air tightness test, get in touch with our team today!
Why choose Melin for your Air tightness requirements?
Choosing a reliable provider for airtightness testing is crucial for ensuring that your building meets the necessary energy efficiency standards and regulations. Here are some reasons why you might consider us for your airtightness testing service:
Our Process
Answer Queries
We are happy to discuss the entire air tightness testing process with you, including what’s involved, important considerations, and the best time to conduct the test. We can also provide helpful guidance and checklists to ensure a smooth experience.
The following checklists are available for download and can assist you in managing the air testing process, from planning and design stages to construction and test preparation:
Date & Price
We offer an indicative price based on the building size and location before providing a formal quote. To create the formal quote, we use PDF drawings of the property. We can work with you to schedule a test date that suits your project timeline, with typical lead times of 1–2 weeks. However, we can often accommodate single tests at shorter notice.
Preparation
Once a test date is confirmed, our engineer will contact you ahead of time to walk you through the preparation process and discuss the test schedule. At this point, we will also confirm the air permeability target outlined in the energy model (SAP) if this hasn’t already been addressed. Achieving the required air tightness is crucial for building control sign-off, as the results are a key factor in calculating the building’s overall energy efficiency.
On the Day of Testing
For smaller houses and flats, we typically handle any temporary sealing required for the test upon arrival at the site. For our larger commercial or multiple unit sites we may require an additional day for preparation works.
We will then conduct the pressure test by installing fan/s in a doorway to create a measurable pressure difference between the inside and outside of the building. The amount of air needed to maintain this pressure helps indicate the volume of air escaping through the building fabric, which would translate to draughts in everyday use.
If the building doesn’t meet its target on the first attempt, our equipment can help identify the points of leakage. If these can be addressed quickly, we can retest on the same day. As air tightness standards become more stringent to meet higher energy performance targets, careful attention must be paid to air permeability in the building design, including the use of membranes and tapes to maintain the air barrier. For more information, refer to our guidance document.
Paperwork
We can provide ATTMA certificates for each test within 24 hours of completion, but same-day issuance is available upon request.
Don’t just take our word for it, if you would like to get in touch to discuss your air tightness requirements, request a quotation or would just like to test our knowledge (we don’t charge for this 😊) please call us on 01554 571010 or email admin@melinconsultants.co.uk.
What are the benefits of Air Tightness Testing?
Air testing is conducted for several key reasons including regulatory requirements, building performance, energy efficiency and occupant comfort;
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