Protective Supply Air Distribution in Hospital Isolation Rooms

Abstract

This study examines healthcare worker (HCW) exposure to patient exhaled airborne pathogens in hospital isolation rooms. Typically, negative pressure is applied to isolation rooms to prevent airborne infections escaping the room. However, negative pressure does not control the airflows inside the isolation room. This study investigates the effect of two different supply air distribution modes on HCW exposure to patient exhaled air: overhead mixing ventilation and local downward air supply. The experiments were carried out in an isolation room model built to a ventilation laboratory. Breathing thermal manikins were used to simulate the HCW and the patient. Smoke visualizations and tracer gas measurements were used to qualitatively and quantitatively assess the HCW exposure. The results show that supply air distribution notably affects the exposure and should be designed carefully in order to decrease the possible exposure. Especially the local downward ventilation showed potential to reduce the HCW exposure throughout the room compared to typical overhead mixing ventilation.