Critical path

[davidyu2404]

I am a little bit confused on this: After pressure balance by design, how could there be a critical path (since all paths have the same pressure loss now)? I am designing a local exhaust system and each path starts from the terminal to the exhaust fan.

 

[EnergyProfessional]

Critical path is the one with balancing damper all open if they did it right.

All paths will have equal pressuredrop - no matter what. Problem is, this is not the flow you want. So you use dampers to reduce the flow while keeping pressure the same in all runs.

 

[willard3]

Critical path is usually but not always the longest run.