R402.4.1.3 Optional Testing Procedure for Buildings With Two or More Dwelling Units Within the Building Thermal Envelope
Where two or more dwelling units are located within the building thermal envelope of a building, the testing procedure specified in Section R402.4.1.3 shall be permitted as an alternative to compliance with Section R402.4.1.2.
In this section, each dwelling unit and each other conditioned occupied space located within the building thermal envelope of the building shall be referred to as a "testing unit," and the "enclosure surface area" within a testing unit shall be equal to the sum of the areas of (i) each exterior wall in such testing unit, (ii) each interior wall in such testing unit that abuts other testing unit(s), (iii) each ceiling in such testing unit that abuts other testing unit(s) or abuts unconditioned space, and (iv) each floor in such testing unit that abuts other testing unit(s) or abuts unconditioned space.
Each testing unit shall be tested and verified as having an air leakage rate not exceeding 0.3 cubic feet per minute per square foot of enclosure surface area within the testing area. Testing shall be conducted with a blower door at a pressure of 0.2 inches w.g. (50 Pascals), and shall be conducted in accordance with ASTM E779. Testing shall be performed at any time after creation of all penetrations of the building thermal envelope.
A written report of the results of the test shall be prepared and signed by the party conducting the test and provided to the building official. The written report shall include:
When the optional testing procedure authorized by Section R402.4.1.3 is used for a building with more than seven dwelling units, testing each testing unit shall not be required, and testing of sample testing units selected in accordance with the provisions set forth below in this section shall be permitted, when approved by the building official.