Experimental study on the effect of exhaust airflows on the surgical environment in an operating room with mixing ventilation

Due to the requirements of indoor environment parameters, including temperature, humidity, air speed and indoor quality, the design of the surgical environment is a very complex task. However, with limited studies on the effective exhaust airflow in the operating room (OR), the impact of exhaust airflow on the surgical environment is still unclear, especially when mixing ventilation with multiple supply and multiple exhaust. The objective of this study was to identify the effect of different exhaust airflow on the air quality in the surgical environment of a full-scaled OR laboratory with mixing ventilation. Experimental measurements were performed with three scenarios of ventilation solutions at two different air change rates. The air velocity, turbulence intensity, air temperature, and tracer gas concentration were measured to evaluate the indoor quality of the surgical environment. The results suggested that a better layout for the instrument table should be placed at 1.0-1.5 m from the wall. Furthermore, airflow from the inlet to the outlet should be guaranteed to cross the clean zone as much as possible, and no obstacles should be placed in the path of the airflow from the inlet to the outlet. The results also indicated that airflow with six exhausts were best, with a higher contaminant removal efficiency of about 38% than eight exhausts in 18 g(-1) ACH, while for 20 h(-1), a four-exhaust strategy was the best at approximately 35% higher than eight exhausts. The results of this study may contribute to more effective ventilation systems for OR.