# Fire walls, metal outlet boxes.



## chris kennedy (Apr 7, 2012)

I have a 1hr fire wall, 3 5/8 metal studs, 24" OC, 5/8 rock on both sides. Is there a way to put 4" sq metal outlet boxes facing both directions in the same cavity?

Thanks.


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## ICE (Apr 7, 2012)

2009 IBC   but I am in California so your code may be different.

713.3.2 Membrane penetrations. Membrane penetrations shall comply with Section 713.3.1. Where walls or partitions are required to have a fire-resistance rating, recessed fixtures shall be installed such that the required fire-resistance will not be reduced.

Exceptions:

1. Membrane penetrations of maximum 2-hour fire-resistance-rated walls and partitions *by steel electrical boxes* that do not exceed 16 square inches (0.0103 m2) in area, provided the aggregate area of the openings through the membrane does not exceed 100 square inches (0.0645 m2) in any 100 square feet (9.29 m2) of wall area. The annular space between the wall membrane and the box shall not exceed 1/8 inch (3.1 mm). Such boxes on opposite sides of the wall or partition shall be separated by one of the following:

1.1. By a horizontal distance of not less than 24 inches (610 mm) where the wall or partition is constructed with individual noncommunicating stud cavities;

1.2. By a horizontal distance of not less than the depth of the wall cavity where the wall cavity is filled with cellulose loose-fill, rockwool or slag mineral wool insulation;

1.3. By solid fireblocking in accordance with Section 717.2.1;

1.4. By protecting both outlet boxes with listed putty pads; or

1.5. By other listed materials and methods.

2. Membrane penetrations by listed electrical boxes *of any material*, provided such boxes have been tested for use in fire-resistance-rated assemblies and are installed in accordance with the instructions included in the listing. The annular space between the wall membrane and the box shall not exceed 1/8 inch (3.1 mm) unless listed otherwise. Such boxes on opposite sides of the wall or partition shall be separated by one of the following:

2.1. By the horizontal distance specified in the listing of the electrical boxes;

2.2. By solid fireblocking in accordance with Section 717.2.1;

2.3. By protecting both boxes with listed putty pads; or

2.4. By other listed materials and methods.

*717.2.1 Fireblocking materials.* Fireblocking shall consist of the following materials:

1. Two-inch (51 mm) nominal lumber.

2. Two thicknesses of 1-inch (25 mm) nominal lumber with broken lap joints.

3. One thickness of 0.719-inch (18.3 mm) wood structural panels with joints backed by 0.719-inch (18.3 mm) wood structural panels.

4. One thickness of 0.75-inch (19.1 mm) particleboard with joints backed by 0.75-inch (19 mm) particleboard.

5. One-half-inch (12.7 mm) gypsum board.

6. One-fourth-inch (6.4 mm) cement-based millboard.

7. Batts or blankets of mineral wool, mineral fiber or other approved materials installed in such a manner as to be securely retained in place.

717.2.1.4 Fireblocking integrity. The integrity of fireblocks shall be maintained.

Putty pads are an option that I discourage because they tend to relax and become loose.

Note that exceptions 1.3 and 2.2 state "solid fireblocking" which eliminates #7 of the choices of fireblocking material.


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## RLGA (Apr 7, 2012)

1.  There is no such thing as a 1-hour fire wall.  Is this a fire barrier or a fire partition?

2.  Follow the items ICE quoted.


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## ICE (Apr 7, 2012)

RLGA said:
			
		

> 1.  There is no such thing as a 1-hour fire wall.  Is this a fire barrier or a fire partition?2.  Follow the items ICE quoted.


Chris is an electrician which means that he has a 1hr. firewall.


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## chris kennedy (Apr 7, 2012)

ICE said:
			
		

> 2009 IBC   but I am in California so your code may be different.


Reads the same in the FBC, thanks.


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## chris kennedy (Apr 7, 2012)

I also recall something saying the box must be attached to a framing member, no old work cut-in boxes. Anyone know where I might find that?


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## ICE (Apr 7, 2012)

chris kennedy said:
			
		

> I also recall something saying the box must be attached to a framing member, no old work cut-in boxes. Anyone know where I might find that?


I haven't seen that in code.  That doesn't mean that it's not there somewhere.  If asked if an old work box could be used I would say that as long as the requirements of section 713 are met, no problem.


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## chris kennedy (Apr 8, 2012)

RLGA said:
			
		

> There is no such thing as a 1-hour fire wall.  Is this a fire barrier or a fire partition?


Sorry, detail lists this as fire partition.

What is the difference between wall, barrier and partition?


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## chris kennedy (Apr 8, 2012)

............


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## chris kennedy (Apr 8, 2012)

> *FIRE BARRIER.* A fire-resistance-rated wall assembly of materials designed to restrict the spread of fire in which continuity is maintained.





> *FIRE PARTITION.* A vertical assembly of materials designed to restrict the spread of fire in which openings are protected.





> *FIRE WALL.* A fire-resistance-rated wall having protected  openings, which restricts the spread of fire and extends continuously  from the foundation to or through the roof, with sufficient structural  stability under fire conditions to allow collapse of construction on  either side without collapse of the wall.


I don't really understand the difference between them.


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## brudgers (Apr 8, 2012)

chris kennedy said:
			
		

> I have a 1hr fire wall, 3 5/8 metal studs, 24" OC, 5/8 rock on both sides. Is there a way to put 4" sq metal outlet boxes facing both directions in the same cavity?  Thanks.


  Last I checked, Florida does not have one hour fire walls.  They were all four hours.


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## brudgers (Apr 8, 2012)

chris kennedy said:
			
		

> Sorry, detail lists this as fire partition.  What is the difference between wall, barrier and partition?


  Wall separates structure into separate buildings.    Barriers go between fire resistant horizontal assemblies (or may go from foundation and to an unrated/rated roof ).

    Partitions may terminate at an unrated floor above and below.


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## Francis Vineyard (Apr 8, 2012)

chris kennedy said:
			
		

> I also recall something saying the box must be attached to a framing member, no old work cut-in boxes. Anyone know where I might find that?


ICE, the code section posted above item 1 limits the amount of unprotected electrical penetrations where as item 2 refers to installed as listed; the manufacturer installation for listed steel boxes is U.L. 263

"*5. Nonmetallic Electrical Outlet Boxes*

Outlet Boxes and Fittings Classified for Fire Resistance (CCN+and+GUIDEINFO'>CEYY) includes Classifications for nonmetallic outlet and switch boxes for use in wall or partition assemblies. The information provided for each Classification includes the model numbers for the Classified products, a description of the rated assemblies, the spacing limitations for the boxes and the installation details. Nonmetallic boxes should not be installed on opposite sides of walls or partitions of staggered stud construction unless Classified for use in such constructions.

*6. Metallic Electrical Outlet Boxes*

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 should have gypsum wallboard facings similar to those shown in Design Nos. U301, U411 and U425. The metallic outlet or switch boxes should be securely fastened to the studs and the opening in the wallboard facing should 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 should not exceed 16 sq in. The aggregate surface area of the boxes should not exceed 100 sq in. per 100 sq ft of wall surface. The aggregate surface area of the boxes may be exceeded when Wall-opening Protective Materials (CCN+and+GUIDEINFO'>CLIV) are installed according to the requirements of their Classification.

Metallic boxes located on opposite sides of walls or partitions should be separated by a minimum horizontal distance of 24 in. This minimum separation distance between metallic boxes may be reduced when Wall-opening Protective Materials (CCN+and+GUIDEINFO'>CLIV) are installed according to the requirements of their Classification.

Metallic boxes should not be installed on opposite side of walls or partitions of staggered stud construction unless Wall Opening Protective Materials are installed with the metallic boxes in accordance with Classification requirements for the protective materials."





Francis


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## north star (Apr 10, 2012)

*= = =*

You could apply some approved type of fire rated sealants

in to the "used" steel boxes and fully seal them......3-M has

an approved, moldable fire sealant.......See the link below:

*http://www.gcssupply.com/en/Fire-Stopping/3M-Putty**-Pads-7x7/FSP04-1010.aspx*

Hilti also has an approved type of moldable sealant - -

CP 618- moldable sealant:......See the link below:

*http://www.hilti.com/holcom/page/module/product/prca_rangedetail.jsf;jsessionid=5F141BB6B1A679C392211BF36BBEA781.node3?lang=en&nodeId=-16135*



FWIW, we have required and allowed this type of

"fully sealing" the electrical components in rated

assemblies.

*= = =*


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## jar546 (Sep 5, 2019)

What about cutting a 2x4 hole in one membrane of a fire-rated assembly and fishing low voltage cable through the wall and then through one of these?:


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## Builder Bob (Sep 5, 2019)

NO! Not listed for such application - See UL listing and limitations of use.

https://legacy-uploads.ul.com/wp-co... and,product category guide information pages.

or show me this on the low voltage box


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## steveray (Sep 5, 2019)

Those are holes....not boxes....


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## jar546 (Sep 5, 2019)

steveray said:


> Those are holes....not boxes....



LOL, agree.  As luck would have it.  I typed that up to resurrect this thread and had to go out to an afternoon inspection that had this exact issue except they used a mud ring.  I laughed and then asked them to put the LV in a rated box.


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## chris kennedy (Sep 5, 2019)

Wow
2012?
I was stupid back then

What’s that dear?

Never mind 
The wife says I’m still stupid.


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## jar546 (Sep 5, 2019)

chris kennedy said:


> Wow
> 2012?
> *I was stupid back then*
> 
> ...



Noooo, don't say it's so!!


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## jar546 (Oct 21, 2020)

Thou shalt resurrect thine thread.  UL 263 is the answer.  
Thou shalt not install cut-in electrical boxes in fire rated assemblies as the boxes must be attached to thine studs which is how the testing is performed.


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## north star (Oct 21, 2020)

*# ~ # ~ #*

Wow, this IS an old Thread !...…….Wonder what Chris did to make it
a compliant installation ?

Oooooooooohhhhhhh Chris, ...can you update us ?......You raised
the topic, so please follow-up with your "compliant application ".
Inquiring minds wanna know !    

*# ~ # ~ #*


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## ADAguy (Oct 24, 2020)

chris kennedy said:


> Wow
> 2012?
> I was stupid back then
> 
> ...


Changes every 3 years Chris, like some change wives?


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