Quantifying suite-level airtightness in newly constructed multi-unit residential buildings using guarded suite-level air leakage testing

Abstract

Improving inter-zonal airtightness in multi-unit residential buildings (MURBs) has wide-ranging benefits including reduced odour/pollutant transfer, reduced sound transmission, and improved energy efficiency. The current metric used to assess inter-zonal airtightness in MURBs is the unguarded air leakage rate, which measures the air leakage through all interior and exterior suite boundaries. While this metric provides a general indication of overall suite airtightness, it provides no information on the location or distribution of leakage pathways across the individual suite partitions. Depending on the construction type(s) of suite partitions there may be variability in air leakage rates at the partition level, which is masked by the whole-suite metric. This makes it difficult to identify potential areas for improvement in design and construction practices.Guarded blower door testing was completed in 14 suites in six newly constructed/renovated MURBs, in Southern Ontario, Canada. Whole-suite air leakage rates for the sample were generally low, consistent with previous studies. Broken down by partition type, floor/ceiling and suite-to-suite walls exhibited similar levels of airtightness, with sample means of 0.36L/s/m2 and 0.32L/s/m2, respectively, at 50Pa (0.07cfm50/ft2 vs. 0.06cfm50/ft2). In contrast, the average suite-to-corridor wall air leakage rate was nearly eight times higher (2.46L/s/m2 (0.49cfm50/ft2)). The results highlight the need to develop targeted air sealing strategies to improve suite-to-corridor wall air leakage rates. Recommendations for improving inter-zonal air sealing practices in new construction are discussed. The measurements reported in this work will also help to improve building airflow simulations, which rely on partition-level air leakage metrics for model inputs.