The Influence of the Direction of Door Swing and Door Velocity on the Transfer of Airborne Contaminants in a Scale Model

Abstract

To assess the effect of the direction of door swing and door velocity on the airborne transfer of contamination, the concentration of a tracer gas (ethane) was measured at various locations in a model consisting of four adjacent rooms between two corridors. Each room had two doors. Ethane concentrations were measured with a hydrocarbon analyzer as a function of pressure differential, direction of door swing, time of door opening and closing, and door velocity. Contamination was transferred in the direction of decreasing static pressure and was proportional to the magnitude of the pressure differential. Opening and closing a door led to exchange of air between the spaces separated by the door regardless of the direction of induced airflow that existed when the door was closed. The extent to which a space was contaminated by opening and closing a door was directly proportional to the time the door was open. Less contamination was transferred when doors opened in the same direction as the airflow induced by the pressure differential than when doors opened against the airflow. Less contamination was transferred when doors were opened slowly; the velocity of door closure had less effect. The protection provided by directional airflow can be increased considerably by making simple alterations in door construction and work practices.