presurization of main stairs¦ building 1

[pablo2410]

Hello

I need to select a fan to presurize a 21 floors bulding´stairs. Which parameter will determine de cfm required for this porpuse? the building is located in Dominican Republic.

Thanks.

 

[willard3]

First you need to know the volume of the stairwell so air changes per hour may be calculated.

Then you need to know tha pressure you want to maintain in the stairwell which will be influenced by the openings to the stairwell.

 

[pablo2410]

ok the volume of the stairwell is 1,100 m3. Which criteria will determine the air changes? and how do i know the pressure i need to maintain

 

[mizzoueng]

I am relatively new, but from my TAB days I think in a stairwell you want 2-3 air changes per hour. The pressure is determined by the pressure on each floor. Are there floors where a positive pressure is required? Or vice versa?

 

[SAK9]

If you were to go by BS 5588-4,

It would be something like this:

With 3 doors fully open(floor on which fire is on+floor just below+exit door)and all other doors fully shut,an air velocity of 2m/s should be achieved across the door area.

Assuming 2.1mx1m doors,

required air flow= 3x(2.1x1m2)x 2m/s=12.6 m3/s

You must add a safety margin for leakage from ducts,doors on other floors,wind effect etc.I have used figures as high as 1.25.

When all doors are closed,a pressure differential of 50 pa must be achieved between the stairwell and the corridor.The force that needs to be exerted at the door handle should not exceed more 100N.