The system is 100% outside air.
Supply Air = 1400 cfm (from 60 ach) + 2 ach exfiltration = 1453 cfm. Where, ach is the air changes per hour.
Exhaust Air = 1400 cfm
This should maintain a slightly positive room pressure because SA > EA.
I am designing the HCAC system for a small clean room (~200ft^2 w/ 8ft ceiling, Class 10,000). The client wants 60 air changes per hour with 0.05 in WG positive pressure (relative to building).
How do I calculate the amount of exhaust air to provide positive room pressurization?
