Developing a pilot test to measure and predict interzonal airflow rates (beta) with a tracer gas

This research developed a technique using the tracer gas sulfur hexafluoride to characterize β under differing ventilation and room conditions. Three rooms were evaluated under two ventilation conditions each. Each condition was evaluated with three test runs. Real-time infrared analyzers were used to measures SF₆ concentrations simultaneously in both zones. These concentrations were used to derive β for each sampling run. A statistically significant relationship between β and the room air change rate (Q/V in min−1) was observed: β = exp(11.8 Q/V + 1.16), r2 = 0.56, p < 0.01. This relationship will be useful in determining values to use for β in future modeling applications. Through a better understanding of the variables associated with airborne exposure modeling, health and safety professionals are able to perform exposure assessments proactively and retroactively under a variety of potential scenarios. This can complement and expand the assessments done through traditional employee exposure assessment techniques such as using a multi-flow sampling pump and media.