Understanding the Meaning of Air Tightness

 

Air Tightness Tests are sometimes referred to as an Air Pressure Test, Envelope Test or an Air Permeability Test. We are basically testing for the unintentional leakage of air in the building that will cause the heating and / or cooling system in the home to work harder than it needs to, leading to an increased environmental impact.

 

A home is not a balloon, so when cold air comes in, warm air gets pushed out, which makes you turn up the heat and pay out the £££'s. ™

 

Test Preparation

 

We will seal all of the intentional leakage areas in the house prior to testing. These include: Fireplaces, Extractor Fans, Exhaust Fans, Trickle Vents, and the odd uninstalled component. Everything else will have to stay 'as is' in the property. It’s strongly suggested that if you’ve never had a test before, that you review the ATT Checklist. (The most important item on the checklist – coffee, white, one sugar please)

 

On your SAP, go to section 4.5 of the L1A checklist and look for the Design Air Permeability figure. It will be a number equal to or lower than 10. Have that available for me on the day please. If you haven’t had a SAP done – shame on you – check out our section on SAPs and EPCs.

 

In 2010 the maximum score you will be able to use will be 7.5, this is due to the Code For Sustainable Homes Level 3 requirement on all new builds which requires a minimum of a 25% improvement on the current building regulations TER.

 

A very windy day on site is not a good thing for testing and would require us to reschedule. Please keep this in mind. It'd be nice if you called to tell me it was blowing a gale before we got there as well.

 

For those that are scared about this test, we also offer a pre-test service that will give you a very good indication of the areas that you need to focus on for the actual test. Please feel free to call us for advice on this.

 

Envelope Area Calculation

 

So that the equipment can understand the readings that it's receiving, we must let it know how big of a space it's testing. With this in mind, the test engineer on site will have to have completed an Envelope Calculation on the property. This will require a scaled copy of the architect’s drawings. We'll either complete this on the day or prior if supplied by you.

 

The envelope area of the building, or measured part of the building, is the total area of all floors, walls and ceilings bordering the internal volume subject to the test. This includes walls and floors below external ground level. Overall internal dimensions are used to calculate this area and no subtractions are made for the area of the junctions of internal walls, floors and ceilings with exterior walls, floors and ceilings.

 

Common Leakage Points

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Top Tips

 

The best place to find more information is on my Blog. Every week, I take things from what I've experienced in the real world and share it with you. Look for tips on Skirting Boards, Gaps, Building Regulations, SAP’s etc.

If you have a general concern, just give me a call and we can talk it though.

 

Passing

Everyone asks, “What do you do if I fail?”

We try very hard not to have a failure with our customers. 95% of the tests that we do pass first time because we walk around with you on site and find the holes. I’m not a building inspector, and I don’t really look for quality. Attention to detail is what's going to get you a pass on the day.

 

Million pound homes all the way to 60k flats all have to be tested. I’ve seen good scores and bad scores on both ends of the spectrum.

 

If, after we have worked together, you're still not passing, then a few things have to be considered. Is this the only house on the site? If so, then we've to get this house to pass regardless and I’ll leave you with a list of suggested actions to get you in the pass zone. If, on the other hand, you’re building multiple houses on the same site, then we've to both get the original to pass and a subsequent duplicate as well. There will be an additional charge for the extra house, sorry.

 

This isn’t a common occurrence and shouldn’t be something you lose sleep over.

 

Reports and Certificates

 

We are able to create your report and the BINDT Certificate for you on site. These documents will be needed by the building control officer to get your building certificate.

 

The report has all the detail required by the regulations to indicate that a valid test has been performed.

 

Please click here to find out more about the report and its elements.

 

The certificate is a serial numbered certificate issued by BINDT to qualified testers. This is not replaceable, so please make a copy and keep hold of it for the building control officer.