Corridor Walls rated but not floors?

[nealderidder]

Three story type V-B apartment building, fully sprinkled... 1018 requires corridor walls to be 30 minute fire partitions. I've also got some occupancy seprarations, vertical stair enclosures, unit separations, and etc.

The question is - am I required to provide any floor/ceiling rating horizontally between 1FL/2FL corrdior and 2FL/3FL corridors? The corridors all stack.

Thanks

 

[High Desert]

I think only exit passageways require the floor/ceiling rating (2009 IBC 1023.3), a corridor does not.

 

[High Desert]

I forgot, you may need a ceiling rating for each corridor dependent upon the construction method for continuity in 709.4

 

[nealderidder]

I guess that's what I have to decide. Do I want to fuss with taking the gyp up to the floor sheathing above or terminate it at a rated lid. Wish I could find that 1 hr rated suspended acoustic tile ceiling assembly I've been looking for...

Thanks

 

[JBI]

Depending on the specific floor-ceiling assembly involved, it may be a matter of using 5/8" type X in lieu of 1/2" on the ceiling, rarely involves "taking the gyp up to the floor sheathing above"... Check the UL and Gypsum books...

 

[High Desert]

The lid is as simple as taking the wall and installing it as the ceiling in accordance with Exception 3 in 709.4. A 1-hr rated suspended ceiling in itself will not make an assembly. You typically have to combine it with some sort of floor/ceiling assembly to get a fire rating.

 

[nealderidder]

I'm doing a suspended acoustic ceiling in the corridors and was trying to get away with no gyp bd ceiling above that. Which I suppose I can do if I want to cut around floor joists and fire caulk them... I think the gyp bd guys would rather just install a lid (I do have a listed assembly that will work) and be done with it.

 

[pmarx]

The question is - am I required to provide any floor/ceiling rating horizontally between 1FL/2FL corrdior and 2FL/3FL corridors? The corridors all stack.

I would say no. I don't believe 709.4 (Continuity of Fire Partitions) require that the supporting construction be rated (for corridors of VB construction) as well but if the partition isn't continuous to the underside of the deck (combustible construction), the space between the ceiling and the sheathing must be fire or draftstopped.

 

[Examiner]

Rated suspended acoustical ceilings have limits on the sizes of the openings for Mech and electrical. This is often missed by the design professional. Read the UL text completely you might be surprised.

The code commentary shows examples of the termination of the gypsum on walls. I disagree with some of their examples. I think the gyp must continue to the underside of the deck or fire blocking otherwise the tested wall assembly is not complete. Ex: the commentary allows one to stop the gyp bd at the bottom of a rated ceiling assembly which is at a different ceiling height than the room’s rated ceiling on the opposite side of the same wall. Fire test are for a complete burn through. If the lower ceiling is penetrated then the rated wall above the ceiling that is left open is now unprotected.

 

[syarn]

if I'm reading this right your proposing to NOT protect the floor/ceiling assembly ONLY in the corridors.....so is the structure supporting the corridor floor/ceilings going to be separate from the structure supporting the "apartment unit separations (vertical & horizontal)", vertical stair enclosures, etc. anything adjacent to these corridors/sharing the other side of the wall so to speak??

aka could your corridor floor/ceilings burn away/collapse in less than 30 minutes and the apartment separation walls would still be able to stand up for 30 mins (assuming u have an NFPA13 fire sprinkler; make it 1 hour if u have an NFPA13R system) and your exit enclosure (stairway) for 1 hour?....although I guess people would have no way to leave their apartment to run to the stairway if the floor in the corridor had collapsed...is this a loop hole in the code???