Wednesday, July 18, 2007

Interior Wall Loading

The 5 psf minimum lateral load on interior walls (2006 IBC 1607.13) is an interesting subject. This minimum load is in the live load section of the code, so I would expect it should be treated as an L load in the load combination equations. Another possible load, however, is internal pressure due to wind loading. If you run through the numbers in ASCE 7-05 6.5.11, you will find that the internal pressure qi x GPpi can easily be 5 psf or more. The wind provisions only require this internal pressure to be applied to exterior elements, but when you think about it, what happens when an exterior door blows open or a window blows out or is left open during a windstorm? You could easily have a situation (imagine a typical elementary school) where a room becomes pressurized relative to a corridor. IBC provision 1607.13 requires not only a 5 psf minimum for interior wall loading, but design for loads to which they are subjected.  Anybody out there ever bother to check interior walls for wind? I dont think 5 psf is too conservative to hedge your bets.

Jim Lutz, P.E., S.E.

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