# Using spray foam for holes



## morg123452000 (Nov 4, 2013)

I'm running romex through studs in a commercial building ..there is a fire wall between warehouse to the next rooms ..where do I need to use spray foam to fill my holes that have run romex through... And if I need to use foam what type should I use?


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## mofos be cray (Nov 14, 2016)

You can't use spray foam. you have to use fire caulking.


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## HertzHound (Jan 22, 2019)

Hilti makes a fire stop foam. I can only imagine how much more it costs compared to regular fire caulk. 

As far as I know, armor cables and metal conduit don’t need a sleeve when going through fire walls. Cables like Cat5 need a metallic sleeve. It probably depends on the rating of the wall. Hopefully you sleeved the Romex through a short section of EMT?

You could also use an EZ path





EZ Path Advantages | STI Firestop


Specified Technologies Inc. is an industry leader in developing innovative fire protection systems that help stop the spread of fire, smoke, and hot gases.




www.stifirestop.com


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## splatz (May 23, 2015)

Be careful if you use a spray foam that its rating is suitable for the fire rating of the wall, there is spray foam fire stop at Home Depot but it's probably not rated for the application. You'll have to fire stop between the sleeve and the wall (best to keep the hole as small as possible) and also pack around the cable where it enters the sleeve. I prefer the putty over the caulk gun stuff. 

There are limits how much of a gap you can fill with firestop. Don't forget you have to fasten the sleeve securely in place. You can't smash a hole with a hammer and float a scrap of EMT in a big wad of putty and call it good. 

In my area using NM in commercial buildings is risky, if you're going to run NM through a firewall you had better cross every I and dot every T and be able to back it up with not only the NEC but the building codes, engineering classification of the building, fire codes, etc. If there's an argument, you might lose even if you're right. It might make sense to run it by the AHJ in advance.


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## Kevin (Feb 14, 2017)

splatz said:


> Be careful if you use a spray foam that its rating is suitable for the fire rating of the wall, there is spray foam fire stop at Home Depot but it's probably not rated for the application. You'll have to fire stop between the sleeve and the wall (best to keep the hole as small as possible) and also pack around the cable where it enters the sleeve. I prefer the putty over the caulk gun stuff.
> 
> *There are limits how much of a gap you can fill with firestop. Don't forget you have to fasten the sleeve securely in place. You can't smash a hole with a hammer and float a scrap of EMT in a big wad of putty and call it good.*
> 
> In my area using NM in commercial buildings is risky, if you're going to run NM through a firewall you had better cross every I and dot every T and be able to back it up with not only the NEC but the building codes, engineering classification of the building, fire codes, etc. If there's an argument, you might lose even if you're right. It might make sense to run it by the AHJ in advance.


So would using something like This work to fill the space inside a hollow block wall, then seal the outside with fire caulk instead? 

All my work with fire penetrations has been poured concrete.. Drill a hole the size of the conduit, and seal it with waterproof fire caulk. Never done block wall penetrations yet.


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## MikeFL (Apr 16, 2016)

morg123452000 said:


> I'm running romex through studs in a commercial building ..there is a fire wall between warehouse to the next rooms ..where do I need to use spray foam to fill my holes that have run romex through... And if I need to use foam what type should I use?


I'm not sure I understand your question.
Are you referring to penetrating the sheetrock on the rated wall?
Or running horizontal within the studs in the rated wall?


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## splatz (May 23, 2015)

Kevin_Essiambre said:


> So would using something like This work to fill the space inside a hollow block wall, then seal the outside with fire caulk instead?
> 
> All my work with fire penetrations has been poured concrete.. Drill a hole the size of the conduit, and seal it with waterproof fire caulk. Never done block wall penetrations yet.


You don't have to fill the void in the cell of the CMU blocks, just seal between the sleeve and the hole in the block (on both sides) and when the wires are in, plug the sleeve with firestop (same way you'd use duct seal).

The instructions for the product you're using will probably say how big of a gap you can fill, maybe 1/4" max or something. So if you're installing 1.5" conduit with a 2" outside diameter your hole must be less than 2.5" if the EMT is centered in the hole ... which it probably isn't...


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## splatz (May 23, 2015)

...


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## mofos be cray (Nov 14, 2016)

splatz said:


> ...


I see


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## splatz (May 23, 2015)

mofos be cray said:


> I see


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## kb1jb1 (Nov 11, 2017)

First find out if it is a true fire wall and not just a demising wall or smoke wall. If it is wood studs and sheetrock it might not be a firewall. I was at a job last summer where the DATA guys used these $400.00 sleeves all over but there were other openings all over. Arch ways,, windows,, the bar joists were not sealed.... There was recessed lighting that was not fire rated in the boxed out sofits around the duct work. It was not a firewall so the Hilti sleeves were not needed.


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## LEVY (Jan 28, 2021)

Kevin_Essiambre said:


> So would using something like This work to fill the space inside a hollow block wall, then seal the outside with fire caulk instead?
> 
> All my work with fire penetrations has been poured concrete.. Drill a hole the size of the conduit, and seal it with waterproof fire caulk. Never done block wall penetrations yet.


This stuff is approved for firewall in my city.

We used it on an office complex we finished out. Inspectors said it was ok to use it.

But then I did a little test, that stuff didn't last long, it got on fire!


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## macmikeman (Jan 23, 2007)

The fire foam sold at Home Depot comes in three different levels of fire protection, the best costing more than the other two. I use it regularly, but in too many instances there are massive cut outs of sheetrock above the ceiling tiles left by others in the firewalls between offices and the hallways of the buildings. I usually fill my holes anyway and then take a magic marker and write - not my work- at all the blatant spots and tell the GC to deal with it before the electrical inspector is called onto the job.


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## kb1jb1 (Nov 11, 2017)

macmikeman said:


> The fire foam sold at Home Depot comes in three different levels of fire protection, the best costing more than the other two. I use it regularly, but in too many instances there are massive cut outs of sheetrock above the ceiling tiles left by others in the firewalls between offices and the hallways of the buildings. I usually fill my holes anyway and then take a magic marker and write - not my work- at all the blatant spots and tell the GC to deal with it before the electrical inspector is called onto the job.


I do the same thing with the markers and tell the GC. I put " This was not me" and date it. I do not put my name in case there is a lawsuit down the road. At least others are now aware of the problem.


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## Kevin (Feb 14, 2017)

LEVY said:


> But then I did a little test, that stuff didn't last long, it got on fire!


I'm not surprised.

I hear hydraulic cement does not burn... lol


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## VELOCI3 (Aug 15, 2019)

If you are running through studs only and not penetrating the wall surfaces you don’t need to firestop. Drilling through the upper and lower plates leading to a rated area (eg floor space or other rated space) you will need to firestop. Going from interior to exterior no firestop. 


Sent from my iPhone using Tapatalk


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