Negative Pressure Isolation Room Triage
Isolation room integrity is based on the differential sink. By exhausting more air from the room than is supplied, the room remains at a lower pressure relative to the hallway. If the exhaust fan loses RPM or the HEPA filters load beyond the blower’s capability, the pressure gradient flips, and the room becomes a massive infection spreader.
The “Pathogen Trap” Dynamics
The efficacy of an AIIR depends on the Volume Offset. By typically maintaining an exhaust rate of 200 CFM over the supply rate, you create a permanent “hole” in the room pressure. This hole is continuously filled by air from the hallway, which prevents any air from the inside from ever traveling back out.
| Containment Zone | Pressure Requirement | Primary Hazard |
|---|---|---|
| AIIR (Standard) | -2.5 Pa minimum | Airborne Tuberculosis/Flu |
| BSL-3 | -30 Pa minimum | Class III/IV Pathogens |
| Corridor | Neutral/Positive | Sterile Transport Route |
Diagnostic Gateway Challenge
The AIIR room is currently reading -1 Pa relative to the hallway. The exhaust fan is at 100% speed. What is the most likely cause of this breach?