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Fire Partition or Fire Barrier required?

Mech

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2015 IBC

Existing 5A building with load bearing exterior CMU walls. A proposed addition turns the existing load bearing exterior wall into an interior load bearing wall, which requires a 1 hour fire rating (due to building type.) The addition will be comprised of three rooms, each accessed from existing individual rooms: proposed 180 sf office storage via an existing office, proposed 180 sf storage room via an existing police station interview room, and a proposed 180 sf office via an existing room (with existing exterior egress door).

What type of wall assembly is this CMU load bearing wall supposed to be - a fire barrier or a fire partition? At the moment, the existing CMU wall extends above the existing rated ceiling and the trusses sit on top of the wall. The existing CMU will extend above the proposed rated ceiling / roof assembly.

Thanks
 

cda

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Sq ft of existing building?

sq ft of addition?

Fire sprinkler system?

Not my area, but unless over the area, I am guessing no rating required.

Sounds like adding like existing occupancy ??
 

Mech

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Existing building is 5750 sf. Addition is 650 sf. Proposed Total is 6,400 sf.

No sprinkler system.

Type 5A construction listed on original plans. No idea why they went this route. Type 5B construction only allows 6,000 sf. I believe I can get a frontage increase to allow the 6,400 sf, but I would like to maintain the 5A construction type to keep with the original unknown reasoning.
 

classicT

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You need to take a look at allowable area to determine if you need a fire barrier. Depending upon the areas of the mixed uses, a fire barrier can either be useful for mixed-use separated, or as a means to reduce fire area to avoid sprinklers. At minimum, given type V-A construction, the interior load bearing wall will be a 1-hr fire partition.

Need a more comprehensive idea of what your constraints are, particularly the Ch. 5 limits for area, and mixed-use separated vs. nonseparated.
 

Mech

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My allowable mixed use non-separated building area for type 5A construction is 11,500 sf. (Group A-3 is allowed 11,500 sf; Group B is allowed 18,000 sf; Group S-1 is allowed 14,000 sf.) The proposed total of 6,400 sf is well within the limitations.

I do not work with the type 'A' construction; we always design type 'B'. I was looking for a code section that specifically states which way to construct the fire rated wall, not that I need to start with a fire partition and then determine if a fire barrier is required.

Thank you for the input.
 

Tim Mailloux

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Feb 12, 2018
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339
Location
Hartford CT
2015 IBC

Existing 5A building with load bearing exterior CMU walls. A proposed addition turns the existing load bearing exterior wall into an interior load bearing wall, which requires a 1 hour fire rating (due to building type.) The addition will be comprised of three rooms, each accessed from existing individual rooms: proposed 180 sf office storage via an existing office, proposed 180 sf storage room via an existing police station interview room, and a proposed 180 sf office via an existing room (with existing exterior egress door).

What type of wall assembly is this CMU load bearing wall supposed to be - a fire barrier or a fire partition? At the moment, the existing CMU wall extends above the existing rated ceiling and the trusses sit on top of the wall. The existing CMU will extend above the proposed rated ceiling / roof assembly.

Thanks

What is the use group of this facility? You mention am existing police station interview in your write up above. Is this a police station? Is there a holding cell? If there is a holding cell then at least part of the existing building is an i-3 occupancy and there should be a sprinkler system through out the entire building.
 

mtlogcabin

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2012 edition I do not have a 2015 version and fire partitions changed in the 2018 version
707.5 Continuity.
Fire barriers 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 and shall be securely attached thereto. Such fire barriers shall be continuous through concealed space, such as the space above a suspended ceiling. Joints and voids at intersections shall comply with Sections 707.8 and 707.9.

707.5 Continuity.
Fire barriers 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 and shall be securely attached thereto. Such fire barriers shall be continuous through concealed space, such as the space above a suspended ceiling. Joints and voids at intersections shall comply with Sections 707.8 and 707.9

708.4 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. In combustible construction where the fire partitions are not required to be continuous to the sheathing, deck or slab, the space between the ceiling and the sheathing, deck or slab above shall be fireblocked or draftstopped in accordance with Sections 718.2 and 718.3 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 and open 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.

4. The fire partitions separating tenant spaces in a covered or open mall building, complying with Section 402.7.2, are not required to extend beyond the underside of a ceiling that is not part of a fire-resistance-rated assembly. A wall is not required in attic or ceiling spaces above tenant separation walls.

5. Attic fireblocking or draftstopping is not required at the partition line in Group R-2 buildings that do not exceed four stories above grade plane, provided the attic space is subdivided by draftstopping into areas not exceeding 3,000 square feet (279 m2) or above every two dwelling units, whichever is smaller.

6. Fireblocking or draftstopping is not required at the partition line in buildings equipped with an automatic sprinkler system installed throughout in accordance with Section 903.3.1.1 or 903.3.1.2, provided that automatic sprinklers are installed in combustible floor/ceiling and roof/ceiling spaces.
 

mtlogcabin

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Is there a holding cell? If there is a holding cell then at least part of the existing building is an i-3 occupancy and there should be a sprinkler system through out the entire building.
Depends on the number of people under restraint


308.4 Institutional Group I-3.
Institutional Group I-3 occupancy shall include buildings and structures that are inhabited by more than five persons who are under restraint or security
 

steveray

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Didn't read all of this so forgive me....Construction type rating is just rated assemblies....No barrier or partition as you are just protecting the structure exposed to fire, not the "migration" of fire and smoke....
 

cda

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Didn't read all of this so forgive me....Construction type rating is just rated assemblies....No barrier or partition as you are just protecting the structure exposed to fire, not the "migration" of fire and smoke....


Bless you, say ten 102.4.1's
 

RLGA

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Didn't read all of this so forgive me....Construction type rating is just rated assemblies....No barrier or partition as you are just protecting the structure exposed to fire, not the "migration" of fire and smoke....
steveray nailed it. 1-hour construction per the construction type is just that: 1-hour construction.

It is not an assembly like fire walls, fire barriers, fire partitions, and smoke partitions; thus, openings and penetrations are not required to be protected. If the wall is a standard 8x8x16 CMU construction, it is very likely that it will have a 2-hour fire-resistance rating...it will definitely have a 1-hour rating.

Since the building is well under the allowable area for the most restrictive occupancy group, there is no requirement that the wall be any type of fire-resistive assembly.
 
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