Calculating room pressure 1

[flamearrow]

Hi Guys,

Is there any method to calculate the room pressure from CFM and other available parameters without measuring from devices?
thanks

 

[willard3]

Not accurately.

 

[lukaiENG]

You can use pressurization calculations which basically apply leakage factors to doors/openings into and out of the space.
I have used a calculation based on stairwell pressurization in the past for this purpose.
These calculations are theoretical only and are highly dependent on the quality of the construction. If the penetrations into the room are poorly sealed then the room will not hold the calculated pressure.

 

[lilliput1]

First the room must be sealed good. Cracks must be caulked. Conduit openings sealed. Brush type door bottom seals used. Have testing & balancing contractor calibrate amount of supply CFM differential over return/exhaust to give design pressurization. Note that pressurization will be lost when door is open. Hospital isolation rooms require room differential pressure sensor & alarm (alarm has time delay to avoid nuisance alarm when door is open). Provide automatic door closer.