Typical Internal Pressures for Reg B

[asixth]

Hi

What are typical internal pressures that people are using for Region B. I have traditionally assumed that the building is permeable and always used a Cpi=0 to -0.3. However I am designing a building with large glazed areas and it was suggested that the building be designed with dominant openings. This increases the internal pressures to Cpi=-0.5 to +0.7 (assuming that the dominant opening may occur on the windward or leeward/sidewall).

I attended an EngAust seminar late last year about the Brisbane windstorms of 2008 hosted by the guys from James Cook Uni, and they really recommended that full internal pressurization be accounted for unless it is proven that the windows can resists impact from flying debris (as typically designed for in regions C and D).

ASCE7 section 6 only considers open, partially enclosed and enclosed buildings for internal pressures (0;-0.55 to +0.55 and -0.18 to +0.18 respectively).

Technical Paper on Brisbane windstorms attached.

http://www.jcu.edu.au/cts/idc/groups/public/documents/technical_report/jcuprd_047446.pdf

 

[rowingengineer]

Cam & John have spent a lot of time at wind affected regions. Their discussions about garage doors being under designed have opened up a can of worms for people in the shed industry. However on the wind born debris situation, and internal pressures, my opinion is that is all has to do with wind speed. If you wind speed is high, then yes 0.7,-0.5 would be smart, however if it is low, 0.2,-0.3 is preferred by me.

Arguing with an engineer is like wrestling with a pig in mud. After a while you realize that they like it