Stairway Pressurization 1

[jbutler42]

Hello. I am designing a pressurization for stairway in a 10 story building. The supply fan is on the roof and the relief duct is located in the second floor ceiling. How do I determine the supply cfm?

 

[cdxx139]

ASHRAE 2003 Application Chapter 52: Smoke Management

Use absolute temperatures (rankine)
height of building
gaps through doors
max allowable PD in stairs per code

Use VFD for balancing
Check the local codes for additional requirements.

Do you need vestibule pressurization? or elevator pressurization?

Good luck

knowledge is power

 

[ChasBean1]

Also ASHRAE has a "Design of Smoke Management Systems" book. As an aside, if you have the design leeway, I'd lean toward pressurizing stairs from the ground floor and not the roof. If it's a high rise, the intake tends to have cleaner air at the ground level than the roof of a building on fire...

 

[SAK9]

CB,

A star for you mate.An important point conveniently forgotten by designers!

 

[ChasBean1]

Thanks SAK9. There are certain clips of buildings on fire (no specifics) that you can look at and say "imagine if my life safety source of air was drawn in from the top." No f-in way. I'll take bottom first, even if it's from a loading dock or subway tunnel...