Published online by Cambridge University Press: 19 October 2009
Operating theatres are ventilated for a number of reasons, one of them being to keep numbers of airborne bacteria low at the operation wound. No matter how air is brought into the room, bacteria are removed by dilution rather than by air currents, because of turbulence caused by heat liberated by people and equipment and by movement in the room (Lidwell & Williams, 1960). With ventilation rates up to 20 air changes/hour, the dilution may differ at different sites in the room depending on the design of its ventilation system.