# rated corridor tunnel



## wilgrp (Feb 12, 2014)

newbie here: i have read references to fire exit tunnels (rated corridor walls with rated "lid" atop walls) ..but have never heard/ found reference to this concept in IBC... is there a trail to follow?

my condition..metal building very high roof deck.. required one hour corridor walls to deck cuts building into cells requiring fire dampers in ducts crossing corridor walls.... any help appreciated


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## mtlogcabin (Feb 12, 2014)

Welcome to the Board

Remember what the big print requires the foot notes and exceptions give away

Exception 3 is probably your answer.

1018.1 Construction.

Corridors shall be fire-resistance rated in accordance with Table 1018.1. The corridor walls required to be fire-resistance rated shall comply with Section 709 for fire partitions .

709.4 Continuity.

Fire partitions shall extend from the top of the foundation or floor/ceiling assembly below to the underside of the floor or roof sheathing, slab or deck above or to the fire-resistance-rated floor/ceiling or roof/ceiling assembly above, and shall be securely attached thereto. If the partitions are not continuous to the sheathing, deck or slab, and where constructed of combustible construction, the space between the ceiling and the sheathing, deck or slab above shall be fireblocked or draftstopped in accordance with Sections 717.2 and 717.3 at the partition line. The supporting construction shall be protected to afford the required fire-resistance rating of the wall supported, except for walls separating tenant spaces in covered mall buildings , walls separating dwelling units , walls separating sleeping units and corridor walls in buildings of Type IIB, IIIB and VB construction.

Exceptions:

1.	The wall need not be extended into the crawl space below where the floor above the crawl space has a minimum 1-hour fire-resistance rating .

2.	Where the room-side fire-resistance-rated membrane of the corridor is carried through to the underside of the floor or roof sheathing, deck or slab of a fire-resistance-rated floor or roof above, the ceiling of the corridor shall be permitted to be protected by the use of ceiling materials as required for a 1-hour fire-resistance-rated floor or roof system.

3.	Where the corridor ceiling is constructed as required for the corridor walls, the walls shall be permitted to terminate at the upper membrane of such ceiling assembly.


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## cda (Feb 12, 2014)

Welcome also

what part of Tx do you practice in N, S, E or W???

I take it the building does not have a fire sprinkler system??

two other thoughts one good and one bad,,

They do make one hour rated grid and tiles, that can be  used.

and section, someone might correct me on this,  720, 721, "721.6.2.1"  "721.6.2.2     2009 IBC      lets you design your own rated assembly.This is kind of what you are asking


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## wilgrp (Feb 12, 2014)

thanks.... i am learning a lot here...

aggieland is my location... although we do a lot of work in surrounding counties... where there is either no cbo or the cbo does not get sufficient c.e.... usually because they can't pay him to do so...


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## steveray (Feb 12, 2014)

As MT said....You can have a rated "lid" on a corridor per the exceptions. And as CDA was getting at I believe, typically the 1 hour rated corridors go away in a sprinklered building...If it is supposed to be a horizontal exit, that is a whole different discussion.


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## mtlogcabin (Feb 12, 2014)

You can design your own using the sections quoted

From the 2012 commentary

"Exception 3 allows for a corridor to be constructed in a "tunnel" fashion-with rated walls and a rated top. In these cases, the walls are not required to extend to the underside of a rated assembly. This is a unique provision in the code and the fact it permits awall assembly to be turned into a horizontal position should not be applied to other sections of the code or rated assemblies. In this one situation, the code will permit an assembly that has been tested as a wall to be turned and used horizontally.......Because one of the primary purposes of a corridor is to stop the spread of smoke versus necessarily stopping a fire"


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## cda (Feb 13, 2014)

Wilgrp

I take it the building does not have a fire sprinkler system??


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## wilgrp (Feb 13, 2014)

correct ...no sprinkler system... think i have it covered from here.. many thanks to all


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