CFD Analysis of the Performance of a Local Exhaust Ventilation System in a Hospital Ward

Abstract

Healthcare workers (HCWs) are at high risk of nosocomial infection as they frequently perform medical procedures on infectious patients that may generate bioaerosols. For example, emergency endotracheal intubations for severe acute respiratory syndrome (SARS) patients. Due to the high zonal bioaerosol concentration close to infection sources (e.g. patient’s breathing zone) local exhaust ventilation (LEV) has been identified as a practical solution to reduce the bioaerosol concentration in hospital wards. In this study, computational fluid dynamic (CFD) models have been developed to simulate the transport of infectious droplets and bioaerosols in a hospital ward to aid the design and control of a LEV system. This paper reports the details of the CFD mathematical models as well as the analyses of the distribution and suspension time of droplets and bioaerosols with respect to their size, emission direction, and emission speed. It is shown that the operation of a well-designed LEV system can effectively remove infectious droplets and bioaerosols from the breathing zone of a HCW.