Air leakage occurs through openings in the building envelope, this air leakage affects the building’s energy performance, The need to reduce CO2 emissions has led to changes in building regulations, therefore buildings now need to meet a level of air tightness. The air-tightness of a building is the air permeability or leakage rate through a structure. Air leakage is the uncontrolled flow of air through the building envelope; this does not include the structure ventilation system.
To determine if building regulations for air tightness are met, a test is carried out, which usually involves placing a blower-fan in the doorway of the structure and pressurising the building envelope. These measurements are used to calculate the air tightness of the structure. A certificate is produced which will be passed on to the SAP assessor who is responsible for assigning a buildings energy rating. In the case of buildings that have an existing energy rating this process can be used to easily improve it’s grading. This test must be carried out after all building works are complete.
Air Tightness Testing & Compliance
Compliance with building regulations Part L is mandatory with new builds, the aim is to reduce CO2 emissions by improving energy performance. Demonstrating compliance with Part L is relatively easy to achieve, removing uncontrolled air flow or air leakage creates a more cost-effective building in terms operational costs but also a more comfortable environment. A sustainable building will be an airtight building but controlled ventilation is also required, to remove pollutant laden air and replace it with fresh air through controlled ventilation, this will also remove excess moisture which can have a negative effect on the occupants health and the structure of the building.
