C406.11 Reduced air infiltration. Measured air infiltration of the total conditioned floor area of the whole building, fully isolated building addition or tenant space shall comply with Section C406.11.1.
C406.11.1 Air leakage testing and verification. Air infiltration shall be verified by whole building pressurization testing conducted in accordance with ASTM E779 or ASTM E1827 by an independent third party. The measured air leakage rate of the building envelope shall not exceed 0.17 cfm/ft2 under a pressure differential of 0.3 in. water (75 Pa), with the calculated surface area being the sum of the above and below grade building envelope. A report that includes the tested surface area, floor area, air by volume, stories above grade, and leakage rates shall be submitted to the code official and the building owner.
EXCEPTION: | Where the conditioned floor area of the building is not less than 250,000 ft2 (25,000 m2), air leakage testing shall be permitted to be conducted on representative above grade sections of the building provided the conditioned floor area of tested areas is no less than 25 percent of the conditioned floor area of the building and are tested in accordance with this section. |