The Influence of Air Motion on Bacteria Removal in Negative Pressure Isolation Rooms.

Controlling the concentration of bacteria in patient rooms to prevent airborne injection is one of the important issues in injection control in hospitals. The effects of air inlet/outlet locations, patient styles of reclining, and air change rate on bacteria removal have been studied. A real hospital isolation room was the object for computation and experiment. In computation, commercial CFD software was used to simulate steady and transient air motion. The flow model was incompressible turbulent flow including buoyancy effect. In the experiment, we used fog generated by an ultrasonic nebulizer to put experimental bacteria into the patient room, and then examined the effect of bacteria removal by means of colony counts. Both computational and experimental results showed that the original design of the isolation room could not remove bacteria effectively. The air inlet/outlet locations were rearranged and the computations and experiments were redone to find better designs. Results of the present study revealed that a large air change rate might not be necessary for most cases. Finally, a set of air inlet/outlet locations and the associated air change rate were suggested. [ABSTRACT FROM AUTHOR]