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Fire walls, metal outlet boxes.

chris kennedy

chris kennedy

Sawhorse
Joined
Oct 24, 2009
Messages
1,535
Location
Miami Fla
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.
 
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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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.
 
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.
Click to expand...
Chris is an electrician which means that he has a 1hr. firewall.
 
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?
 
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?
Click to expand...
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.
 
RLGA said:
There is no such thing as a 1-hour fire wall. Is this a fire barrier or a fire partition?
Click to expand...
Sorry, detail lists this as fire partition.

What is the difference between wall, barrier and partition?
 
FIRE BARRIER. A fire-resistance-rated wall assembly of materials designed to restrict the spread of fire in which continuity is maintained.
Click to expand...
FIRE PARTITION. A vertical assembly of materials designed to restrict the spread of fire in which openings are protected.
Click to expand...
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.
Click to expand...
I don't really understand the difference between them.
 
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.
Click to expand...
Last I checked, Florida does not have one hour fire walls. They were all four hours.
 
chris kennedy said:
Sorry, detail lists this as fire partition. What is the difference between wall, barrier and partition?
Click to expand...
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.
 
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?
Click to expand...
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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= = =

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.

= = =





 
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?:
BB10L-BLI-0-2.jpg low_voltage_mounting_bracket_1_gang_ARL_LV1__63280.1407367088.1280.1280.jpg
 
steveray said:
Those are holes....not boxes....
Click to expand...

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.
 
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.
 
# ~ # ~ #

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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