Airflow in High-Rise Multi-Unit Residential Buildings with Respect to Ventilation and IAQ

Airflow into, out of, and within buildings is a fundamental factor of indoor air quality, comfort, durability, and energy consumption. Multi-unit residential buildings are uniquely complex in this respect due to a number of design factors which differentiate them from other building types including the typical inclusion of operable windows, the compartmentalized nature of the interior space, and height. This paper provides the findings of an experimental program conducted at a case study building which was conducted to better understand airflows in multi-unit residential buildings. The analysis includes assessment of the potential impact of the building enclosure energy efficiency upgrades on airflow and ventilation patterns as well as of the performance of the corridor pressurization based ventilation system.

The experimental program carried out at the case study building includes measurement of airflow rates provided by the make-up air unit, measurements of the flow rates between zones of the building using PFT tracer methods, and longterm monitoring of pressure differences at various locations across the exterior enclosure as well as between internal building zones. The interior and exterior environments were also monitored including measurements of temperature, relative humidity, wind speed and direction, and carbon dioxide concentration at various locations throughout the building. Pressure equalized airtightness testing was performed to quantify the resistance to airflow provided by the exterior enclosure and interior compartmentalizing elements.

Overall, this study works to improve the understanding of: airflow patterns in high-rise multi-unit residential buildings; the potential impact of enclosure airtightness improvements on airflow and ventilation patterns; and the performance of corridor pressurization based ventilation systems. This knowledge can then be applied to effective and efficient ventilation strategies to optimize indoor air quality and energy consumption.

This paper was presented at the 2013 ASHRAE IAQ Conference.