Air Tightness Testing
In Scotland, air tightness testing is required for all new buildings, including residential and non-residential buildings, as well as buildings undergoing major renovation. The testing is required to comply with the Scottish Building Regulations, specifically Section 3 (Ventilation) and Section 6 (Energy) at the SAP/EPC stages.
Our partner-certified air tightness tester conducts testing under the Air Tightness Testing and Measurement Association (ATTMA) guidelines.
The testing involves pressurising the building and measuring the air leakage using specialised equipment. We report results as an air permeability rate, measured in cubic meters per hour per square meter of building envelope area. The maximum permitted air permeability rate for new buildings in Scotland is 7m3/hm2.hr @50Pa.
Air tightness testing requirements may vary depending on the building’s ventilation design. As a result, consulting with a qualified professional is always recommended to ensure regulatory compliance.
Air Tightness
Air tightness refers to the measure of how effectively a building or structure can prevent air leakage between the interior and exterior environments. In other words, it is a measure of how well the building envelope, which includes the walls, roof, windows, doors, and other components, can prevent air from entering or escaping.
A blower door test measures a building’s air tightness. It uses a fan to pressurise or depressurise the building and identifies air flow through leaks or gaps. A lower air leakage rate means that the building is more air tight and can result in improved energy efficiency, indoor air quality, and overall comfort. Achieving high air tightness requires careful design, construction, and testing. This ensures adequate ventilation while preventing condensation and mould growth.
How many tests to do?
A single air tightness test at the end of construction or during commissioning often verifies the building envelope’s air tightness. Additionally, this test identifies leaks or areas of concern that need addressing before the building is occupied.
Sometimes, projects require additional air tightness tests, particularly when targeting low values or completing retrofits. In these cases, it may be useful to perform additional air tightness tests to ensure that the building will meet the desired air leakage targets and to identify any new leaks that may have been introduced.
