Air Permeability
Air permeability is the rate at which air leaks from a building envelope under a specified pressure. This measurement is the volume of air leaking from a building per hour per square metre of building envelope, x m3 h-1m-2 @ y pascals (pa). The envelope area is the area of the walls plus the roof and the floor slab.
With increasing concerns over carbon dioxide emissions and energy efficiency air tightness requirements are becoming more stringent, and an air test is also becoming a stand-alone requirement.