Protocol for field testing of tall buildings to determine envelope air leakage rate

The objective of this project was to develop a relatively simple, accurate method for testing the overall envelope leakage rate of tall buildings. Two fan pressurization test techniques, the floor-by-floor blower door method and the air-handler method, were developed and tested on two buildings. Criteria for conducting accurate tests were developed, including limitations on outdoor air temperature and wind speed. The floor-by-floor blower door method permits isolation and measurement of the leakage flow rate of a single floor, but it is difficult and time-consuming to apply. The air-handler method uses building air distribution fans for pressurization. It is most easily applied on a system-by-system level rather than floor-by-floor. Fan airflow techniques including orifice plate, pitot traverse, and tracer gas dilution were considered. The tracer gas method was found to be relatively easy to apply and highly accurate. Fan airflow rate measurement uncertainty by tracer gas was estimated to be 5.4% to 8.8% for the cases considered, assuming a 5% uncertainty in interzonal leakage.