Inter-zonal airflow in multi-unit residential buildings: A review of the magnitude and interaction of driving forces, measurement techniques and magnitudes, and its impact on building performance.

Inter-zonal airflows within multi-unit residential buildings (MURBs) have profound impacts on an array of building performance metrics, including energy, indoor air quality (IAQ), fire and acoustical separations, and distribution of ventilation air. Although there are wide-ranging implications, most building codes/standards have yet to incorporate airtightness requirements for interior partitions in large, multi-zone structures, and instead focus primarily on exterior envelope airtightness. Despite the multi-disciplinary nature of the topic, previous reviews have been limited to one domain (eg, energy performance, IAQ, specific test methods). This paper presents a comprehensive summary of the literature on inter-zonal airflow in MURBs including the magnitude and interaction of driving forces; its relevance to/effect on building performance; current code requirements; testing methods; and previous measurements. While considerable efforts have been made in recent years to quantify and control inter-zonal airflows, most measurement techniques are still labor-intensive and disruptive, and there is no framework for how to implement performance-based requirements into building codes and standards. Further research efforts should be focused on refining testing methods and preparing the construction industry for code changes.