environmental control

Natural ventilation has been appraised as the main strategy in environmental control of airborne infection in resource-limited healthcare facilities. While natural ventilation offers a low-cost alternative in diluting and removing contaminated air, its’ performance in actual settings is not fully understood. This paper reports a cross-sectional field study of six hospitals in Thailand with an emphasis on ventilation performance of naturally-ventilated hospital wards and AII rooms. The results showed that ventilation rates of 3-26 ACH could be achieved in hospital wards.

The paper describes small scale wind tunnel experiments on the dispersion of contaminants discharged from the bottom of courtyards and other enclosed spaces. The experiments covered a range of courtyards with ratios of depth to width from 5- (consistent with light wells and other very deep cavities) down to 0.1 (consistent with shallow enclosed squares and piazzas that are frequently found in the urban environment).