Section R303.4 of the International Residential Code for One- and Two-Family Dwellings is hereby amended to read as follows:

303.4 Mechanical ventilation. Where the air infiltration rate of a dwelling unit is less than 3 air changes per hour when tested with a blower door at a pressure of 0.2 inch w.c. (50 Pa) in accordance with Section N1102.4.1.2, the dwelling unit shall be provided with whole-house mechanical ventilation in accordance with Section M1505.4.