Experimental study of an air distribution system for operating room applications

An understanding of airflow patterns in operating rooms is required if the design of air distribution systems in such environments is to be improved and the risk of postoperative infection reduced. To assess a detailed description of contaminant distribution, the airflow patterns and the spread of contaminants in an operating room were analyzed using an experimental model. These experiments were carried out in a test cell, MINIBAT, equipped with an operating table, a medical lamp and a manikin representing the surgeon. A diagonal ventilation system was tested for two types of conditions: (i) isothermal, with the manikin and lamp switched off and (ii) non-isothermal, with the manikin and lamp switched on. Indoor air temperatures, air velocities and tracer gas concentrations were measured automatically at more than 700 points. The overall airflow patterns, due to ventilation, were very similar for the two experiments. However, in the zone between the lamp, the table and the manikin (which was the main area of interest), the tracer gas distribution was different. In the non-isothermal case, the thermal plume from the manikin induced better mixing, and had a beneficial effect on the evacuation of contaminants. The thermal energy emitted by the lamp had almost no impact on the airflow patterns.