In sterile processing department layout design, which requirement should the IP recommend?

• A. Area should be under negative air pressure
• B. Humidity should be 20-40%
• C. Area should have a minimum of eight air exchanges per hour
• D. Area should be under positive air pressure

Answer: (D)

In sterile processing, protecting the cleanliness of the space hinges on how air moves between rooms. The area should be kept under positive air pressure relative to adjacent spaces. Positive pressure makes air flow out of the clean area when doors or hatches are opened, which helps prevent unfiltered air from the surrounding, potentially dirtier areas from seeping in and contaminating sterile instruments and packaging. This outward flow is what helps maintain a consistently low level of contaminants inside the processing area. Negative pressure, by contrast, is used to contain contaminants within a room (such as in isolation or clean-isolation setups), so it would pull air into the clean area if used here, which is undesirable. While humidity and the rate of air exchanges are important factors for overall environmental quality and contaminant dilution, the defining requirement for preserving sterility in the SPD is maintaining positive air pressure to keep contaminants from entering the clean space.