605.1.2.2 Testing Requirement

The building thermal envelope air tightness shall be considered to be acceptable where the tested air leakage of the total area of the building thermal envelope is less than 0.25 cfm/ft² under a pressure differential of 0.3 in water column (1.57 lb/ft²) (1.25 L/s.m² under a pressure differential of 75 Pa). Testing shall occur after rough-in and after installation of penetrations of the building envelope, including penetrations for utilities, heating, ventilating and air-conditioning (HVAC) systems, plumbing, and electrical equipment and appliances. Testing shall be done in accordance with ASTM E 779.