1. Calculate the building envelope air leakage in accordance with guidelines in ASTM E3158-18 multi-point regression tests or the relevant building envelope area when testing in sections.
2. If the building envelope air leakage rate exceeds 0.4 cfm/ft² but is less than 0.6 cfm/ft², a visual inspection of the air barrier shall be conducted in accordance with NA5.7 Any leaks observed should be sealed where such sealing can be made without destruction of existing building components. An additional report identifying the corrective actions taken to seal air leaks should be submitted to the building owner and code official, and any further requirement to meet the air leakage rate will be waived.
3. If the building envelope air leakage rate exceeds 0.6 cfm/ft², a visual inspection of the air barrier shall be conducted in accordance with NA 5.7, and any leaks noted should be repaired. The building will then be re-tested until either the building envelope air leakage rate less than 0.4 cfm/ft², or the building envelope air leakage rate is in the range of 0.4 cfm/ft² but is less than 0.6 cfm/ft² and a visual inspection and repair program is executed.

Exception to NA5.6.3 Alterations where less than 100% of the wall area is being altered or additions that are an extension of the existing air barrier, if the building is tested in accordance with the procedures for whole building air leakage in NA5 and the tested leakage rate exceeds 0.6 cfm/ft² of building shell area at 75 pa, a Visual Inspection and Diagnostic Evaluation shall been completed in accordance with NA5.7 and all observed leaks shall be sealed where such sealing can be made without destruction of existing building components. An additional report identifying the corrective actions taken to seal air leaks should be submitted to the building owner and code official, and any further requirement to meet the air leakage rate will be waived.