Exit enclosure/corridor continuity

[Codegeek]

I have a four-story wood frame hotel that has a 2-hour exit enclosure that adjoins a 1-hour rated corridor. I'm having troubles in determining how to maintain the continuity of the exit enclosure with the intersecting corridor. There is a 4x16 inch beam that serves as the structural support for the 2x6 floor joists from the corridor where the joists are hangered onto the beam. My question is do the two layers of gypsum need to cover the beam or can the floor joist intersect with the beam and have the two layers stop under the joist?I'm including two sketches, one with the gypsum continuous and the other with the gypsum stopping at the bottom of the joist. I'm not finding any good code language that clearly indicates how this should be constructed. Thanks for your feedback.

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[cda]

Can you show a floor plan diagram of the enclosure and corridor

 

[Francis Vineyard]

FWIW metal hangers are now available to support joist that can be installed over 2 layers of 5/8-in. gypsum.

http://publicecodes.cyberregs.com/icod/ibc/2009f2cc/icod_ibc_2009f2cc_7_par085.htm?bu2=undefined

 

[mtlogcabin]

Have you considered changing the beam from 4 to 6 inches and looking at 722.6.3 to see what the calculated fire resistance might be?

Or

Drawing 2 is the correct option.

 

[Codegeek]

mtlogcabin, my first thought was to check it for the fire resistance but that's when I found out it was only 4 inches. If we could get the calculated fire resistance to be two hours, then I think option one would work.

I appreciate the feedback from everyone. I had an instinct that option 2 was correct, but wanted to confirm.