Receptacles In Restaurant Firewalls

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Ravenvalor

Senior Member
Someone was kind enough to post the following code in a 2009 thread (see below). Does anyone know whether or not it has changed since 2009? I am looking at an existing metal stud construction that is being converted from an office space to a restaurant space. The inspector is having customer modify a one hour fire wall into a two hour firewall by adding three layers of sheet rock with an air gap in-between layers 2 and 3. There are existing receptacles in this firewall. Do I have to apply the code quoted below? If so, is there a firestopping product that I may put on the inside of the box? I do not think there is therefore I am under the assumption that I will have to damage the sheetrock in order to install the firestopping wrap on the outside of the boxes. If someone has a handle on how to treat these electrical boxes I would appreciate the advice.

Thanks,


"From the UL White Book

USE IN FIRE-RATED ASSEMBLIES
Listed single- and double-gang metallic outlet and switch boxes with metallic or nonmetallic cover plates may be used in bearing and nonbearing
wood stud and steel stud walls with ratings not exceeding 2 h. These walls have gypsum wallboard facings similar to those shown in Design
Nos. U301, U411 and U425, as covered under Fire Resistance Ratings ? ANSI/UL 263 (BXUV). The boxes are intended to be fastened to the studs
with the openings in the wallboard facing cut so that the clearance between the boxes and the wallboard does not exceed 1/8 in. The boxes
are intended to be installed so that the surface area of individual boxes does not exceed 16 sq in, and the aggregate surface area of the boxes does
not exceed 100 sq in per 100 sq ft of wall surface. Boxes located on opposite sides of walls or partitions are intended to be
separated by a minimum horizontal distance of 24 in. This minimum separation distance between the boxes may be reduced when Wall Opening
Protective Materials (QCSN) are installed according to the requirements of their Classification. The boxes are not intended to be installed on opposite sides of walls or
partitions of staggered stud construction unless Wall Opening Protective Materials (QCSN) are installed with the boxes in accordance with Classification
requirements for the protective materials. Listed metallic outlet and switch boxes with metallic or nonmetallic cover plates may be used in floor-ceiling and roof-ceiling assemblies with
ratings not exceeding 2 h when these assemblies have gypsum wallboard membranes. The boxes are intended to be fastened to the joists with the openings in the wallboard facing cut so that the clearance between the boxes and the gypsum wallboard does not exceed 1/8 in. The boxes are intended to be installed so that the surface area of individual boxes does not exceed 16 sq in, and the aggregate surface area of the boxes does not exceed 100 sq in per 100 sq ft of ceiling surface."
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
Someone was kind enough to post the following code in a 2009 thread (see below). Does anyone know whether or not it has changed since 2009?
The information is not a code, it is explaining how boxes must be installed in rated assemblies in order to maintain the UL listing of the assemblies. A building inspector, Fire Marshal, etc... would / could use this to determine if the rating is in tact.

I am looking at an existing metal stud construction that is being converted from an office space to a restaurant space. The inspector is having customer modify a one hour fire wall into a two hour firewall by adding three layers of sheet rock with an air gap in-between layers 2 and 3. There are existing receptacles in this firewall. Do I have to apply the code quoted below?
In order to maintain the rating the short answer is yes.
If so, is there a firestopping product that I may put on the inside of the box?
There are new products coming on the market continuously that might give you options, contact Hilti, 3M, Rectorseal, etc..., they may be able to help.


"From the UL White Book

USE IN FIRE-RATED ASSEMBLIES
Listed single- and double-gang metallic outlet and switch boxes with metallic or nonmetallic cover plates may be used in bearing and nonbearing
wood stud and steel stud walls with ratings not exceeding 2 h. These walls have gypsum wallboard facings similar to those shown in Design
Nos. U301, U411 and U425, as covered under Fire Resistance Ratings ? ANSI/UL 263 (BXUV). The boxes are intended to be fastened to the studs
with the openings in the wallboard facing cut so that the clearance between the boxes and the wallboard does not exceed 1/8 in. The boxes
are intended to be installed so that the surface area of individual boxes does not exceed 16 sq in, and the aggregate surface area of the boxes does
not exceed 100 sq in per 100 sq ft of wall surface. Boxes located on opposite sides of walls or partitions are intended to be
separated by a minimum horizontal distance of 24 in. This minimum separation distance between the boxes may be reduced when Wall Opening
Protective Materials (QCSN) are installed according to the requirements of their Classification. The boxes are not intended to be installed on opposite sides of walls or
partitions of staggered stud construction unless Wall Opening Protective Materials (QCSN) are installed with the boxes in accordance with Classification
requirements for the protective materials. Listed metallic outlet and switch boxes with metallic or nonmetallic cover plates may be used in floor-ceiling and roof-ceiling assemblies with
ratings not exceeding 2 h when these assemblies have gypsum wallboard membranes. The boxes are intended to be fastened to the joists with the openings in the wallboard facing cut so that the clearance between the boxes and the gypsum wallboard does not exceed 1/8 in. The boxes are intended to be installed so that the surface area of individual boxes does not exceed 16 sq in, and the aggregate surface area of the boxes does not exceed 100 sq in per 100 sq ft of ceiling surface."

Roger
 

mwm1752

Senior Member
Location
Aspen, Colo
My understanding is that metal boxes are rated at 1.5 hrs, so protection is needed for a penetrations in that wall -- have them furrout with metal studs outside of the rated assembly and you will have no penetration issues
 

Ravenvalor

Senior Member
I am having trouble interpreting the literature. It says 24" horizontally no other outlets shall be within without using fire stopping material. Does that include both directions? It seems like if there is a stud in the wall between two outlets then this 24" rule does not apply. Thank you for the help
 

cadpoint

Senior Member
Location
Durham, NC
Put it this way, I've never put anything in a fire rated assembly that wasn't
wrapped with fire caulk and 24" inches away from each other. Usually the rated assembly is
only the walls that are common to tenant spaces and where the oven(s) go.

I used extended device rings in these walls. Per reading the UL; I might have been wrong in
over placement and maybe even over pasted but I never failed an inspection for it either.

Make sure to determine the finish depth of what this new fire walls is.
On restaurant walls, make sure to see if they are adding a wash board panel to finish
the rated assembly with might add to your extension ring depth!

Now the cheat, I've seen boxes placed flush with the first piece of sheet rock, knowing that
the second and third will cover it up, this was also required because they only
make certain depths of device extension rings.
 

Ravenvalor

Senior Member
Great advice. It looks like adding 2 - 4x4 extensions will be the easiest approach for this application. It will require 2 - puddy pads per box which will total 8 but it's a good way to prevent fire spread. Thanks very much
 

Ravenvalor

Senior Member
Now the cheat, I've seen boxes placed flush with the first piece of sheet rock, knowing that
the second and third will cover it up, this was also required because they only
make certain depths of device extension rings.

Did they calculate for 2 - 5/8" sheetrock pieces? If so what type of extension ring did they use? This particular wall we are doing is already a one hour fire wall and they're making the owner add 3 - more sheets of sheetrock with a 7/8" gap between the first and the second. They are also inspecting each layer of sheetrock before the next one can be installed.
 

cadpoint

Senior Member
Location
Durham, NC
I guess an RWI is in order!

I looked at Appleton they went up to 2" deep on a single and double gang extension
rings. You are going to have to open your's up to puddy pad any was, right?

Just make up the difference with a standard extension ring and a shorter extension.
In OP you said a total of three layers, now it's four? Seems like your working within
the UL as clear as that read... up to 16" sq in. opening with padding....

Give Arlington and or your favorite/best supply house a call Monday before you shoot a RWI!
 

Ravenvalor

Senior Member
I guess an RWI is in order!

(What is an RWI? Pardon my ignorance.)

I looked at Appleton they went up to 2" deep on a single and double gang extension
rings. You are going to have to open your's up to puddy pad any was, right?

(Yes sir, I removed the plaster ring, added 2 - 4 x 4 box extensions and then reinstalled the plaster ring. It measures up to about 2 3/4" protruding from the original sheetrock.)


Just make up the difference with a standard extension ring and a shorter extension.
In OP you said a total of three layers, now it's four? Seems like your working within
the UL as clear as that read... up to 16" sq in. opening with padding....

(My apologies, it's 3 - layers of sheetrock added and 1 - layer of air space between first and second sheetrock.)

Thanks Cadpoint.
 

Ravenvalor

Senior Member
Had a chance to see the other side of wall today and there were no outlets with in24" of my outlets. The closest outlet was 72". The customer was quite pleased when he heard the news that he did not have to pay for puddy pads.

Thanks,
 
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