Pressure build-up Calculation in Rooms
Pressure build-up Calculation in Rooms
(OP)
Hi everyone,
Is there any way that I can calculate the pressure build-up in a room by just knowing the inlet + exhaust flow rates and room volume?
I understand leakages through door gaps should be taken into consideration and they can be calculated using Q = 0.827*A*P^(1/N) [This is in SI units]. However, in my case, I don't know the value of P, the differential pressure across the adjacent rooms currently since there isn't any PDT around.
I do know the design pressure differential of the rooms, but after 10 years of running the plant with no one to work on HVAC optimisation, and no PDTs for certain rooms, we figured it's most likely that the DPs have deviated from design.
Any miraculous way of calculating this without using instruments?
Is there any way that I can calculate the pressure build-up in a room by just knowing the inlet + exhaust flow rates and room volume?
I understand leakages through door gaps should be taken into consideration and they can be calculated using Q = 0.827*A*P^(1/N) [This is in SI units]. However, in my case, I don't know the value of P, the differential pressure across the adjacent rooms currently since there isn't any PDT around.
I do know the design pressure differential of the rooms, but after 10 years of running the plant with no one to work on HVAC optimisation, and no PDTs for certain rooms, we figured it's most likely that the DPs have deviated from design.
Any miraculous way of calculating this without using instruments?





RE: Pressure build-up Calculation in Rooms
Short answer: No, you can not calculate a roompressure(difference) from just knowing the inlet and exhaust flow rates.
The difference between inlet and exhaust flows through cracks and there is no way of knowing what the characteristics of the cracks and openings are.
RE: Pressure build-up Calculation in Rooms
(This whole subject of room pressures keeps popping up a lot... do we need a FAQ for this subject?)
RE: Pressure build-up Calculation in Rooms
RE: Pressure build-up Calculation in Rooms
Thanks anyway!
RE: Pressure build-up Calculation in Rooms
RE: Pressure build-up Calculation in Rooms
In this case, we suspect that the fans may be oversized and are trying to find out what are the actual airflows supplied and extracted.