# One hour wall under steel beam



## Vlab20 (Feb 14, 2011)

I have a UL U423 wall assembly hitting the underside of a beam that runs parallel over my wall. The wall is a required one hour occupancy separation. I have found plenty of UL assemblies to fire treat the beam but I am looking for a drywall wrap of the beam that would maintain the required one hour rating. My wall is a 3-5/8" metal stud wall with 5/8" Type X drywall on both sides. There is steel stud framing around both sides of the beam with 5/8" Type X drywall. Inspector is looking for a UL. I am trying to argue that my U423 wall meets the requirement that the inspector seeks. Anyone have any UL or other back-up info that I can use to assure inspector that the 1-hour is being met.Thanks

View attachment 1496


wall beam detail.pdf

wall beam detail.pdf


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## Mule (Feb 14, 2011)

What about Figure 704.3? Isn't that what you are basically doing?


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## Vlab20 (Feb 14, 2011)

Figure 704.3??? I have no Fig 704.3 Can you point me in the right direction?

Thanks


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## Builder Bob (Feb 15, 2011)

Calculated fire resistance. I would accept said drawing if the steel studs are a nominal 2" in depth or width that abut the steel beam.


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## Mule (Feb 15, 2011)

Here ya go! This is from the 2009 Commentary


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## RLGA (Feb 15, 2011)

Builder Bob:  I thought about the calculated method, too, but when I checked, the IBC does not provide a calculated method for beams and girders using gypsum board...just SFRM.  Only the steel column section provides a gypsum board method.

Check out UL N501 and N502.  These are 2-hour assemblies.  UL doesn't have any 1-hour assemblies that I could find.


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## Vlab20 (Feb 15, 2011)

Builder Bob, Mule and RLGA...thank you for the direction.


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