{"id":3446,"date":"2022-10-12T11:53:22","date_gmt":"2022-10-12T10:53:22","guid":{"rendered":"https:\/\/www.bcta.group\/attma\/?page_id=3446"},"modified":"2025-04-04T13:39:19","modified_gmt":"2025-04-04T12:39:19","slug":"attma-faqs","status":"publish","type":"page","link":"https:\/\/www.bcta.group\/attma\/attma-faqs\/","title":{"rendered":"ATTMA FAQ’s"},"content":{"rendered":"

ATTMA Frequently Asked Questions<\/h2>\n


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\n\t\t\t\t\t\tThe Best Way To Air Tightness Test \u2013 The ATTMA App\t\t\t\t\t<\/a>
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In this 6 part series, Chris Milsom (CM), Digital Marketing and Membership Coordinator sat down with Paul Carling (PC), Technical<\/p>\n


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\n\t\t\t\t\t\tThe Best Way To Air Tightness Test \u2013 The New ATTMA Technical Standards\t\t\t\t\t<\/a>
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In this 6-part series, Chris Milsom (CM), Digital Marketing and Membership Coordinator sat down with Paul Carling (PC), Technical Manager<\/p>\n


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\n\t\t\t\t\t\tThe Best Way To Air Tightness Test \u2013 Sealing in Air Tightness Testing?\t\t\t\t\t<\/a>
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In this 6-part series, Chris Milsom (CM), Digital Marketing and Membership Coordinator sat down with Paul Carling (PC), Technical Manager<\/p>\n


\n Learn more <\/a>
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\n\t\t\t\t\t\tThe Best Way To Air Tightness Test \u2013 What do Buildings Need to Achieve?\t\t\t\t\t<\/a>
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In this 6-part series, Chris Milsom (CM), Digital Marketing and Membership Coordinator sat down with Paul Carling (PC), Technical Manager<\/p>\n


\n Learn more <\/a>
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\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/p>\n

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\n\t\t\t\t\t\tThe Best Way To Air Tightness Test – What Needs to be Tested?\t\t\t\t\t<\/a>
\n\t\t\t\t<\/h2>\n

In this 6-part series, Chris Milsom (CM), Digital Marketing and Membership Coordinator sat down with Paul Carling (PC), Technical Manager<\/p>\n


\n Learn more <\/a>
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\n\t\t\t\t\t\tThe Best Way to Air Tightness Test – Common Air Leakage Paths\t\t\t\t\t<\/a>
\n\t\t\t\t<\/h2>\n

In this 6-part series, Chris Milsom (CM), Digital Marketing and Membership Coordinator sat down with Paul Carling (PC), Technical Manager<\/p>\n


\n Learn more <\/a>
\n <\/p>\n

Facts about Air Tightness Testing that you may not have known.<\/h2>\n

\t\t\t\t\t\t\t\t\t\t\t\tThe Pressure is 50Pa, but you can barely feel it.<\/a><\/p>\n

We test at 50Pa pressure difference which is barely noticeable at all. It’s the equivalent of blowing on the back of your hand. In fact, if the fan made no noise, you would not normally know an airtightness test is being conducted.<\/p>\n

\t\t\t\t\t\t\t\t\t\t\t\tAll homes have air leakage, even the good ones! <\/a><\/p>\n

All buildings will leak an amount of air, even when the fan isn\u2019t running. This is why we take background readings (sometimes called static pressures) to measure how the air is moving through the building naturally.<\/p>\n

Taller buildings leak much more air naturally due to the stack effect. This is where warm air rises and escapes in the top of the building, drawing in cooler air towards the bottom of the building. The opposite happens in warm climates.<\/p>\n

\t\t\t\t\t\t\t\t\t\t\t\tYour air tightness testing result is not directly related to energy loss in your home!<\/a><\/p>\n

Air tightness testing checks the building fabric at a given pressure (normally 50Pa). Many other factors account for how much energy loss you will have in the home, including stack effect, location and size of leakages, ventilation type, wind direction, internal to internal temperatures and barometric pressure.<\/p>\n

\t\t\t\t\t\t\t\t\t\t\t\tMeasurements are made at 50Pa for accuracy and repeatability, not realism!<\/a><\/p>\n

We measure using 50Pa, even though the average natural pressure difference is around 4Pa to ensure the natural pressure difference doesn\u2019t affect the measurement.<\/p>\n

Another way to think about this, you wouldn\u2019t measure acoustics by playing a TV loudly, you use a very loudspeaker to overcome any background differences. With airtightness we do the same.<\/p>\n

\t\t\t\t\t\t\t\t\t\t\t\tThe air pressure changes in a split second once we start the fans!<\/a><\/p>\n

We don\u2019t need to \u2018fill the building with air\u2019 because the building is already full of air! We just need to create a small amount of pressure to force the air out of the gaps and cracks in a building<\/p>\n

\t\t\t\t\t\t\t\t\t\t\t\tUp until 2022, we only tested a sample of houses! <\/a><\/p>\n

Chances are if you live in a relatively new-build house, your plot may not have been subjected to air tightness testing at all. Up until the latest issue of building regulations in England, Wales and Scotland in 2022, the regulations allowed a sample of plots to be tested.<\/p>\n

This is why some houses are much worse than the house the data was copied from. This has now been fixed going forward in the new Building Regulations.<\/p>\n

\t\t\t\t\t\t\t\t\t\t\t\tHigh air leakage means high smoke leakage!<\/a><\/p>\n

Energy isn\u2019t the only reason we conduct air tightness tests. A badly performing house or apartment may mean there is a much bigger problem such as smoke leakage paths which breach fire barrier regulations.<\/p>\n

\t\t\t\t\t\t\t\t\t\t\t\tThere are actually 3 ways of testing air leakage in homes<\/a><\/p>\n

The most common by far is fan pressurisation testing (or blower door testing). This involves using a small fan in a doorway or window to create a pressure difference inside to out.<\/p>\n

Pulse testing \u2013 involves pressurising a 40 litre pressure vessel and letting the air out at once. Some mathematics determines the air leakage<\/p>\n

Tracer Gas Testing \u2013 this involves releasing precise amounts of an inert gas and testing to see how long this gas takes to discharge from the building. This is the most accurate method but takes too long to perform regularly on a building site.<\/p>\n

\t\t\t\t\t\t\t\t\t\t\t\tAir tightness testing doesn\u2019t take long to do the test<\/a><\/p>\n

In fact, the average test only takes around 10 minutes in a new-build home.<\/p>\n

It\u2019s the setup that takes a while (typically between 20 and 60 minutes, depending on the size of the house).<\/p>\n

The test involves:<\/p>\n

Travelling to site
Bringing the equipment from The van to the site,
Installing the equipment into The aperture for testing
Very precisely measuring the envelope area,
Sealing ventilation systems,
Measuring temperatures,
Measuring barometric pressure
Measuring background pressures (static pressures)
Conducting the test.<\/p>\n

This is then repeated in reverse!<\/p>\n

\t\t\t\t\t\t\t\t\t\t\t\tThe Air tightness testers have to undergo a lot of training! <\/a><\/p>\n

A new tester undergoes a minimum of 4 days training which results in a theory and practical tests.<\/p>\n

They then conduct 3 further tests which are again assessed.<\/p>\n

Once assessed, they register with ATTMA and are subject to an on-site audit<\/p>\n

Every year at least an ATTMA auditor will conduct an on-site audit to check the tester is still performing correctly.<\/p>\n

Off-site audits are also conducted on random tests to ensure compliance. Any test they do can be checked through the ATTMA Lodgement system!<\/p>\n\n\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

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