What is negative pressure?

Negative pressure is commonly used to create isolation rooms for patients with airborne infections. Pathology and histology labs also use negative pressure to keep odors and airborne chemicals from migrating to other areas of the hospital. Other common negative pressure rooms include:

• ER waiting rooms
• Radiology waiting rooms
• Triage
• Restrooms
• Darkrooms
• Autopsy rooms
• Soiled linens and trash chute rooms
• Janitors' closets

In terms of rooms in a hospital, negative pressure does not mean the absence of pressure; rather, it is when an area has a lower pressure than the spaces around it. Negative pressure rooms are designed to contain harmful airborne contaminants including bacteria, viruses, fungi, and VOCs. Maintaining differential pressure between the negative room and the adjacent space helps limit particle transmission. To prevent contamination from escaping, a negative pressure room must have sealed windows and doors.