Negative pressure room
Negative room pressure also known as ‘airborne infection isolation’ and ‘infectious isolation units’, is an isolation technique used in hospitals and medical centers to prevent cross-contaminations from room to room and to reduce transmission of disease via the airborne route. It includes a ventilation that generates negative pressure to allow air to flow into the isolation room but not escape from the room, as air will naturally flow from areas with higher pressure to areas with lower pressure, thereby preventing contaminated air from escaping the room. Negative pressure rooms in hospital are for isolating patients capable of transmitting infection by airborne droplet nuclei. Patients are placed in negative pressure rooms to reduce transmission of disease via the airborne route. Negative pressure rooms are used to isolate patients with airborne contagious diseases such as tuberculosis, measles, or chickenpox.
In critical spaces like laboratories, pharmacies and isolation rooms, room pressure is paramount to the safety of not only the occupant but the entire building. An airborne infectious isolation room is designed with the patient space negatively pressurized relative to the corridor to ensure building occupants outside the room are safe from contamination. In the same manner, a protective environment room is positively pressurized relative to the corridor to ensure that contaminants are kept out of the patient space.
Negative pressure is generated and maintained by a ventilation system that removes more exhaust air from the room than air is allowed into the room. Air is allowed into the room through a gap under the door (typically about one half-inch high). Except for this gap, the room should be as airtight as possible, allowing no air in through cracks and gaps, such as those around windows, light fixtures and electrical outlets. Leakage from these sources can compromise or eliminate room negative pressure.