Code Readiness Final Project Report, Multifamily Building Air Leakage Field Study

In 2021 PG&E’s Code Readiness Program research team (research team) initiated an evaluation of measured building air-leakage rates in multifamily buildings across California. Several past studies tested air-leakage rates in multifamily buildings and dwelling unit compartmentalization rates, but most of these studies were performed in colder climate states and are not directly transferable to California. Therefore, there is a general lack of California specific multifamily blower door testing research into actual air-leakage rates of multifamily buildings. To address this knowledge gap, the Code Readiness research team recruited six multifamily buildings throughout California and conducted blower door testing to measure dwelling unit total leakage compartmentalization rates (CFM50/ft2-total), dwelling unit exterior surface leakage rates (CFM50/ft2-exterior), and whole building leakage rates (ACH50, CFM50/ft2) in two of the buildings. This report presents analysis findings including median leakage rates, summaries by building type, and an estimation of leakage attributed to dwelling units and common areas for two buildings that were tested for whole building leakage.