Fire rated installation

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dom

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I can't locate a UL approved system for installing surface mounted back to back boxes on a 2-hour rated firewall.
The boxes are 4s or 4 11/16", or perhaps a surface mounted non-metallic wiremold box connected by a 3/4" emt chase with compression connectors. (perhaps using connectors with reducing washers on the connectors for the non-metallic box install.)

Anyone heard of a good method for this?

Thanks
 
dom said:
I can't locate a UL approved system for installing surface mounted back to back boxes on a 2-hour rated firewall.
The boxes are 4s or 4 11/16", or perhaps a surface mounted non-metallic wiremold box connected by a 3/4" emt chase with compression connectors. (perhaps using connectors with reducing washers on the connectors for the non-metallic box install.)
Click to expand...

314.3 is worth a look but does not answer your fire rating problem.
 
I was told by a State Fire Marshal the holes are small enough that they give you your 2 hr rating.

I had already surfaced mounted my boxes, because I was going to install them on the studs but I to was worried about the fire rating.

Ask your Inspector(s) and get it in writing
 
dom said:
I can't locate a UL approved system for installing surface mounted back to back boxes on a 2-hour rated firewall.
The boxes are 4s or 4 11/16", or perhaps a surface mounted non-metallic wiremold box connected by a 3/4" emt chase with compression connectors. (perhaps using connectors with reducing washers on the connectors for the non-metallic box install.)

Anyone heard of a good method for this?

Thanks
Click to expand...

I seen several UL rated wall penetrations, I frankly thought it was also a building code and also usually spec'd on new construction drawings.
Still with a box in this 2 hour rated wall space, I just usually putty pad the box, for the switch or receptacle.

Understand the fired rating starts on the outside of surface goes inward. So what is inside has to match or excide what one trying to do. So because it is a opening, one is trying to keep an equal plain of safety to the outside surface. Another example is right angle flashing of a duct through all walls. One maintained a closure to the surface,
is my point.

If there are to be two different circuits in the same cavity space of a 2 hour rated wall I've also seen it stated:
One has to maintain some physical separation. I was recalling receptacles in the wall with 18"to 24" inches. I've even done the separation of LV and normal power. But that may be another issue...

Bottom Line: If one disturbs the wall you have to meet or exceed the construction due to the application.
 
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Ask for a flange box, :) Most times I just get to install what they send.
You might make note if this is to be contracted out and inform whomever of the rating.
Also ask if theres a secondary box required for the equipment, getting to be less stand-alone
with 2 boxes now than not.

The head placed over your own equipment protects your own install...
your own entries into the panel will be minimial, seems I always used compression fittings
around the panel and in the wall till out of that space.
 
Thanks for all the answers.
It comes up on many jobs where we have to install raceway through a firewall.
We will use a UL system that simply involves using a particular type of firecaulk around the raceway as the wall entry point. But lately we have been working on jobs that we must connect classrooms together with SURFACE mounted junction boxes connected through a wall with a conduit (3/4" to 1"). The job detail for this penetration involves using threaded pipe or running thread, with locknuts and reducing washers. Since this is costly I was looking for a similar method using emt and connectors.
Thanks again
 
Fire-rated walls

Fire-rated walls

The source of this rules is the UL Fire Resistance Directory...Volume 1, page 10 Wall and partition assemblies. AHJ have variations varying with the product or application....check with the inspector...
 
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