An air tightness test is required in order to ensure buildings are compliant with Building Regulations for England and Wales. Part L of the Building Regulations is mandatory for new builds. The aim of Part L is to reduce CO2 emissions. This can be achieved by improving the energy performance of a building.
Part L looks at a buildings air leakage to determine how energy efficient a building actually is. Air tightness testing is effectively a test for air leakage. Air leakage can occur through openings in the buildings envelope. An air tightness test helps determine if a building is energy efficient and also helps to highlight areas in which it can be improved.