firewall rated boxes

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dcl34769

dcl34769

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Can anyone tell me if they make a firewall rated cut-in box? I am doing a commercial tenant build-out and would like o use cut-ins but am having trouble locating any. the drywall is finished and painted and i don't want to cut open the wall. If a box doesn't exist can I putty-pad the box then install? Any help is appreciated.
 
You are allowed to install a box in a rated wall. You might be limited to 100 sq. inches in 100 sq. ft. If you can get a copy of the IBC or UBC, whichever is adopted in your area. Check with the GC or AHJ. Hopefully you can verify what's on the other side of the wall, cuz you're limited to a 24" lateral separation. BTW, I don't know of a "fire rated" box.
 
Putty pad or use Metacaulk "box guard" or Hilti insert pads if the the boxes on opposite sides of rated walls are within 24" of each other. IBC 711 However back to back is not permitted regardless.
 
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As far as I know in order for the wall to maintain it's rating the boxes must be secured to the studs.

OW Boxes are out.
 
cowboyjwc said:
What iwire said. You will find it in the Gypsum Assosiation fire resistive manuel.
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If the intended OW box is "listed" for the "Rated" wall assembly and all applications of IBC 711 and USG handbook are met what is the problem?
 
Here is the info.

From Volume One of the UL Fire Resistance Directory.


WALL AND PARTITION ASSEMBLIES
Metallic Eletrical Outlet Boxes
Listed single and double gang metallic outlet and switch boxes with metallic or nonmetalliccover plates may be used in bearing and nonbearing wood stud and steel stud walls with ratings not exceeding 2h. These walls shall have gypsum wallboard facings similar to those shown in Design Nos. U301,U411, and U425. The metallic outlet or switch boxes shall be securely fastened to the studs and the opening in the wallboard facing shall be cut so that the clearance between the box and the wallboard does not exceed 1/8 in. The surface area of individual metallic outlet or switch boxes shall not exceed 16 sq in. The aggregate surface area of the boxes shall not exceed 100 sq in per 100 sq ft of wall surface.

Metallic boxes located on opposite sides of walls or partitions shall be seperated by a minimum horizontal distance of 24in. This minimum seperation distance between metallic boxes may be reduced when "Wall Opening Protective Materials" (CLIV) are installed according to the requirements of their Classification.

Metallic boxes shall not be installed on opposite side of walls or partitions of staggered stud construction unless "Wall Opening Protective Materials" are installed according to the requirements of their Classification.
Click to expand...
 
From Volume One of the UL Fire Resistance Directory.


WALL AND PARTITION ASSEMBLIES

Metallic Eletrical Outlet Boxes

Listed single and double gang metallic outlet and switch boxes with metallic or nonmetalliccover plates may be used in bearing and nonbearing wood stud and steel stud walls with ratings not exceeding 2h. These walls shall have gypsum wallboard facings similar to those shown in Design Nos. U301,U411, and U425. The metallic outlet or switch boxes shall be securely fastened to the studs and the opening in the wallboard facing shall be cut so that the clearance between the box and the wallboard does not exceed 1/8 in. The surface area of individual metallic outlet or switch boxes shall not exceed 16 sq in. The aggregate surface area of the boxes shall not exceed 100 sq in per 100 sq ft of wall surface.
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Roger
 
Hello Bob, I didn't see that you had beat me to the punch. :smile:

Roger
 
dcspector said:
Interesting, RACO "old work" Grip Tite box. Rated for 2hr.?:-?
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Greg, first of all you don't look like a fool.

As far as an OW box being listed for use in a rated wall, it can be listed for use in a rated wall, but the intended method of it's use may not be the method of use that allows it to be installed in the rated wall.

Roger
 
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