Scottish Air Tightness Standards | Air Tightness Testing Ltd.

Does Scotland have different air tightness testing standards to the rest of the UK?

According to Scottish building regulations Section 6, all new domestic dwellings are to be tested for air tightness as a mandatory measure.

The UK regulations for air tightness already stand. As written in Building Regulations Part L1A 2010 all new dwellings are to be built airtight to aid with conservation of fuel and power usage.

Part L1A specifies an air tightness of a maximum 10m3/hr/m2 of air lost at a pressure of 50 Pascals (Pa.) However, most properties won’t be built to anywhere near this slack a standard, as the general UK good practice figures instead sit at 7m3/hr/m2, and best practice figures are generally agreed upon to be around 3m3/hr/m2.

Specific Scottish Air Tightness Regulation

Scottish regulations are stricter, with Section 6 of the Scottish Building Regulations stating a maximum air loss figure of 7m3/hr/m2, equivalent to the good practice figures in the UK.

This regulation has been in force since October 2011, and testing is mandatory for all new dwellings. These rules may be strict, but when you consider that in the average UK home around 15% of total heat produced is lost through drafts, they begin to make sense.

When you also consider that the average regional temperature of Scotland is -0.2 degrees during winter, it’s vitally important to for builders and contractors to correctly insulate properties, preventing massive energy loss, for the environmental impact and cost implications both.

Part L1A Requirements

Amount of each type of dwelling	Amount of tests required per dwelling type
4, or less	Two tests on each type of dwelling
More than 4, and less than 40	Three tests on each type of dwelling
Over 40	At least: 10% of the type of dwelling. If the first 5 tested all meet requirements, total sampling frequency can be reduced by 2%

Scottish Building Requirements

Frequency of pressure testing	Description of dwelling
Baseline	Minimum frequency of testing should be at least 1 in 20
Large Development	Testing of more than one of each type of dwelling should be standard, at different states of build, to test for consistency
Smaller Development	Tests should be frequent and consistent enough to establish a representative sample, dependent on the type of development
A single dwelling	Single dwellings should be tested, unless the default design value of 15m3/hr/m3 can be demonstrated in line with standard 6.1.

How are air tightness tests in Scotland carried out?

As in the rest of the UK, air tightness tests in Scotland are to be carried out using a blower door test, in line with regulations set out in document BS EN 13829.

These types of tests require specialised door mounted blowing equipment, or fans, that fit onto most standard door frames and pressurise the interior of the building.

Reading can be taken, and using thermographic cameras, smoke testing and other equipment, leaks and vulnerabilities can be found.

Air tightness is a vital part of sustainable housing and long term design. For help and advice on air tightness, or a personalised quote, contact Air Tightness testing Ltd. today.