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Published Mon, Sep 12th 2011

Air Pressure Testing is a Force for Good

Research recently carried out by the BRE, on behalf of the ATTMA and BINDT, indicates that in a typical UK dwelling, improving the air-tightness of its fabric from 16 to 5 m3/(m2.hr)@50Pa reduces the space heating load during the heating season by around a third.

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Research recently carried out by the BRE, on behalf of the ATTMA and BINDT, indicates that in a typical UK dwelling, improving the air-tightness of its fabric from 16 to 5 m3/(m2.hr)@50Pa reduces the space heating load during the heating season by around a third.

Furthermore, it is reasonable to assert that proportionate reductions in space heating load are attained by improving air-tightness from say 10 to 5 m3/(m2.hr)@50Pa, which is the sort of impact that air-tightness testing has had since its introduction into Part L1A in 2006.

Considering the number of plots built since (plus all the non-dwellings), and the number of heating seasons that they'll each experience, then we are taking about a vast saving in energy, cost and carbon. So, wouldn't it be reasonable to assert that air-tightness improvement, driven by pre-completion testing, is a force for good?

Not according to Mr Edmund Vaughan in his recent widely published article, in which he appears to suggest that the increased air-tightness testing that the new Part L1A 2010 stipulates will "add up to 60 per cent to the cost of ensuring a building is compliant for very little additional value". As well as being baseless, this statement is reckless, resulting in one interpretation that "...new Part L pressure testing regulations could add up to 60 percent to the cost of developing residential property" (from the article "RICS study shows true cost of Part L").

Air-tightness testers will typically charge less than £100 per plot when testing several in a visit. Indeed, the recession and increased competition are driving fees down. Moreover, the cost of air-tightening an average dwelling is probably little more, when typically all it requires is a little more attention to detail and some targeted sealing. Yet, as underlined by the research, the benefits are lasting, substantial and escalating with the price of fuel.

Mr Vaughan also suggests that "sample testing" is no longer an option under 2010 part L1A, when categorically it is; and more's the pity when usually the only way to ensure that a dwelling will be adequately air-sealed is the prospect of it being independently tested. In our experience, Site Managers unashamedly target air-sealing work on only the plots ear-marked for testing. To be honest, if I was in their boots, so would I! The notion that developers seeking to recommence house-building are going to be "in for a nasty shock" as a result of the increased air-tightness testing requirements is pretty absurd when we are talking about something that amounts to around 0.0006 of the cost of modest dwelling!

So, granted, there's a housing shortage but let's get real; increased air-tightness testing - or indeed Part L as a whole - is not going to stop developers building. That's the preserve of the banks. Meanwhile, there is also a changing climate and escalating fuel prices to consider. Haven't the owners and occupants of new homes a right to expect them to be as efficient as possible?

A 'fabric-first' approach to energy efficient building, exemplified by Passivhaus, is now widely accepted. Notably, while requiring fastidious design and construction quality procedures, Passivhaus still requires 100 percent air-tightness testing.

Rob Coxon Chair- Air Tightness Testing & Measurement Association (ATTMA) Director, Stroma Technology Ltd. 

Ends

Notes to editors:

BRE - Building Research Establishment ATTMA - Air Tightness Testing & Measurement Association BINDT - British Institute of Non-Destructive Testing

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