Project Negative Air Machine

Q: Our projects department is using a HEPA negative air machine to pull negative air in a construction area, but we cannot agree where the discharge from this negative air machine can go. In your opinion, where can the air be exhausted to?

A: This issue is not regulated by NFPA standards, so you can pretty much discharge the air from a HEPA negative air machine anywhere you are permitted to by your Infection Control people. I have no problem discharging it into a corridor, but I know some IC people do not like that as the velocity of the discharge air can stir up other contaminants in the corridor. Also, the noise of the air being discharged from the negative air machine can be loud.

While it is best to discharge the air to the outdoors, that is not always possible. Discharging to an exhaust duct above the ceiling is an option, but you have to make sure the HEPA negative air machine does not overpower the exhaust fan and create a positive air pressure in the exhaust duct.

The best solution is to discuss it with the IC people and go by what they recommend.