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Fire barrier wall construction

L

Lipets

Registered User
Joined
Feb 12, 2022
Messages
46
Location
Florida
New build 20,000' divided into 3500' units. This is a metal building.
Fully sprinklered
Question I have is it appears I need a one hour rated wall.
I intended to use 3 5/8" metal studs with 5/8" Type X drywall.
Since one layer of 5/8" is rated for one hour do I need it on both sides or can I use say 1/2" standard on the opposite side.

Most examples show 5/8's type X on both sides.

Some examples also show insulation inside the wall, I don't think it's required

Last point.
CHAPTER 25 GYPSUM BOARD AND PLASTER SECTION 2501
2508.4 Joint treatment.
Gypsum board fire-resistance-rated assemblies shall have joints and fasteners treated.

Exception: Joint and fastener treatment need not be provided where any of the following conditions occur:

3. Square edge or tongue-and-groove edge gypsum board (V-edge), gypsum backing board or gypsum sheathing.

If I'm reading this correctly the drywall can be unfinished?
 
You don’t need to paint the sheetrock, but you should tape and bed the joints to close any gaps or wide joints.
 
A bit confused here as to why you need Fire Walls. Even if was any A Occupancy (all other Occupancies would be less restrictive) you would be permitted 38,000sf without any frontage increase for a Type II-B building. Not having all the clues I would look at a non-separated mixed use occupancy, you may not need rated partitions between the units.
 
Lipets said:
THe use is unknown for each prospective tenant
Click to expand...
Hold up.... do you have an architect involved in the project?

You mentioned the need for 1-hr rated walls. Are you suggesting the use of fire barriers for mixed use separated? Why the fire rated construction?

Without knowing the occupancies, it is very likely that you cannot determine if the building is even compliant with the allowable area per Table 506.2. Depending on construction type and what the occupancies end up as, you may even be able to go mixed use non-separated.
 
The building type B2, occupancy is S-1.
A preliminary meeting with the building dept they said a one hour fire petition is needed.
 
Lipets said:
The building type B2, occupancy is S-1.
A preliminary meeting with the building dept they said a one hour fire petition is needed.
Click to expand...
Go back to my previous comment. It appears a non-separated mixed use occupancy would work with the S-1 being most restrictive. Type II-B would be permitted 70,000sf.
 
Fire partitions or barriers need to be rated from both sides, so you would need 5/8" type X on both sides. I've always seen joints taped & one coat compound (finish level 1 or fire-taping).

Are you under an older code that requires rated partitions between tenant spaces? As far as I know that went away a few editions ago.
 
you maybe correct table 602 of latest code if I'm reading it correctly says distance over 30' (we are 35')
All types of construction, all group S1 or S2
0 fire rating
 
According to ASTM C1396/C1396M Standard Specification for Gypsum Board, Section 13.1, “Gypsum board, except for pre-decorated gypsum board, is intended to be a substrate. The surfaces of gypsum board shall be true and free from imperfections that would render it unfit for finishing and final decoration. Gypsum board shall be installed and finished to the specified level in accordance with Specification C840.” All gypsum board used in interior wall and ceiling applications should be finished with tape and joint compound embedded in joints and interior angles, as well as an appropriate primer and paint. The application of these materials protects the integrity of gypsum board. Note, in a fire-rated system that includes multiple layers of wallboard, only the visible, board surface needs to be finished with tape, joint compound, primer, and paint. Paint and primer are unnecessary only in concealed areas that receive little or no active use, examples include attics and plenum areas above ceilings. Paint and primer are not necessary for these areas but tape and joint compound are required to provide fire resistance. To determine the level of finish appropriate to a specific situation, including gypsum panel products used as a substrate for tile, as a base for textured finishes, wallcoverings, and paints of various sheens, and lighter and darker tones, consult GA-214-2015, Recommended Levels of Finish for Gypsum Board, Glass Mat and Fiber Reinforced Board, available in the GA Bookstore.
 
It will work under a V-B construction type fully sprinkled is allowed 36,000 sq ft. Then you do not need to consider non-combustible construction in the tenant spaces.
 
Lipets said:
VB is wood not metal correct?
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Not always. Type V allows any material permitted by the code. You can have a 9,000 sq. ft., Group B, nonsprinklered building constructed completely of cast-in-place concrete and call it Type VB construction. Refer to IBC Section 602.1.1.
 
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