Air is the primary carrier of heat, moisture, contaminants, and airborne pathogens in patient rooms, isolation rooms, and operating rooms. Temperature levels and contaminant concentrations in patient rooms depend on how the supply air is distributed within the space. Such distribution of supply air and the resulting temperature levels determine the thermal comfort, air quality, and potential for transmission of airborne pathogens in the room.
The airflow patterns, temperature distribution, and concentration of contaminants including the flow path of airborne pathogens in a patient room can depend on several factors. The factors include the location and type of supply diffusers, supply air flow rates (air change rates), associated diffuser throws, supply air temperature, size and locations of the room return, bathroom exhaust flow rates, locations and strengths of various heat sources in a room, arrangement of furniture, and other obstructions to airflow, and relative location of the patient in the room. In addition, orientation of the room can determine the solar sensible heat loads in the room that can affect the airflow patterns.