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What is an air leakage test for?
Is there any difference between the terms "air leakage test", "air test" or "air permeability test"?
Do industrial buildings need an air leakage test?
Do houses need an air test?
Can I use any air testing company?
Are any types of building exempt from having an air test?
Why bother with an air permeability test?
How is an air leakage test conducted?
How much is a building "pumped up" in a test?
What is a Pascal?
How much do the regulations allow a building to leak?
What air permeability figures do buildings generally achieve?
What's the best result you've measured?
What do I have to do to prepare for an air test?
What is an air leakage test for?
The test shows how much air leaks from your building. As the air escapes it takes heat with it. The heat was likely created by burning a fossil fuel. The more air leaks the more fuel needs to be burned, and the more CO2 is produced.
Is there any difference between the terms 'air leakage test', 'air test' or 'air permeability test'?
No. They all mean the same thing. People just refer to them differently. We use all three descriptions throughout this website.
Do industrial buildings need an air leakage test?
Yes, if the floor area is more than 500m2. Floor area is calculated as the ground floor area (footprint) plus the area of any additional floors.
Do houses need an air test?
Yes. All houses do, but if you are building an estate with many houses then you only need test a representative sample. The definition of what exactly a "representative sample" is, is due to change in the forthcoming 2010 Buildings Regulations revision.
Can I use any air testing company?
Yes and no! To avoid problems with Building Control and the possibility of your air test certificate being rejected, you should ensure that you only use a fully accredited company. In the UK they should hold either ATTMA, UKAS or BINDT accreditation. Do be aware however, that some accreditations don't cover the testing of industrial buildings. Air Leakage Testing Ltd is fully UKAS accredited to ATTMA TS1 issue 2 BS EN 13829:2001 and ISO/IEC 17205 (testing). That means we're certified to test both industrial buildings and domestic dwellings. We're also registered with the Constructionline scheme for Health & Safety.
Are any types of building exempt from having an air test?
Yes. Details can be found in the ATTMA TS1 issue 2 document and the Building Regulations.
Why bother with an air permeability test?
Three good reasons:
- Minimising air loss, and thus reducing heat loss, will save you loads of money.
- It reduces CO2 emissions - which is good for the planet.
- Building Regulations insist you have to!
How is an air leakage test conducted?
In simple terms, we set up pressure testing and temperature recording equipment in the building to be tested. We then attach an electrically driven door-mounted blower unit - a large fan - to a suitable opening in the building envelope having first ensured that all the doors, windows and ventilation openings are closed. We then start the fan and pressurise the building.
How much is a building "pumped up" in a test?
The pressures involved aren't that great. Visions of roof sheets popping off and windows blowing out are unfounded. The pressures we work with are normally in the 55-60 Pascals (Pa) range, although in certain conditions this may be increased to 100Pa (see - What is a Pascal? below). What we do need is lots of air. We use sets of fans capable of delivering 30m3 of air per minute.
What is a Pascal?
A Pascal (Pa) is a metric unit of pressure. As guidance 1psi is roughly 6,900Pa, so even 100Pa is a still a very low pressure. Atmospheric pressure is about 100,000Pa, or about 14.5psi
How much do the regulations allow a building to leak?
The maximum amount a building is allowed to leak is currently 10m3 per hour per m2 at 50Pa. This is as defined in Part L2 of the Building Regulations (Conservation of Fuel and Power), but may need to be lower if your design air permeability figure was specified at a lower level. The 2010 Building Regulations are expected to reduce the maximum permitted to 8m3 per hour per m2 at 50Pa.
What air permeability figures do buildings generally achieve?
We find that most houses, if well built, achieve between 5-7m3 per hour per m2 at 50Pa. Industrial units generally achieve between 7-10m3 per hour per m2 at 50Pa. In both cases however, we've seen buildings that outperform that.
What's the best result you've measured?
We tested one house which achieved 0.5m3 per hour per m2 at 50Pa, which is exceedingly good! The best industrial unit we've tested was just over 3m3 per hour per m2 at 50Pa
What do I have to do to prepare for an air test?
Have a look at our air leakage test picture gallery to see the items you should seal or make sure are finished prior to the test. Common sense detailing at the eaves, verges, around windows/doors and other junctions will effectively block all gaps. Most buildings that fail do so because of poor workmanship and site supervision, rather than design faults. Once you have booked your air test with us we will provide you with a full list of what you can and can't seal up, what has to be open and closed, and what you may need to remove before we can carry out a test. A contractor's representative should be on site throughout the test. We can also review your drawings to help you avoid costly problems before building commences.