Firestopping / Draftstopping Steel Studs

[greenwoodpatriot]

I am in the middle of a project that consists of steel stud framing using all MC / conduit methods and now have a hiccup.

The friendly inspector informed me that we have been incorrectly using firestop (3M CP25WB+) to seal our penetrations through the steel top plate. He is of course correct in this observation, my question is do you all know of any firestop / draftstop (different areas) product that I could use to seal a 3/4" - 1" hole containing MC cable.

I am trying not to resort to pulling cables out and placing sheetrock in the cavities, securing sheetrock, drilling holes, replacing cables and then applying firestop. I have been told there is a Hilti product that I could potentially use, but you have to be Hilti certified to apply it...

And yes, now that I have done further research I see now it was a bonehead move. Not that it matters, but we have done it for years and every other inspector has been wrong in approving it.

 

[JFletcher]

Welcome to the forum

I have never heard that 3M red (CP25WB) isnt good for MC cable. From their site:

"Applications
High-performance 3M™ Fire Barrier Sealant CP 25WB+ is ideal for sealing single or multiple through penetrations in
fire-rated construction. 3M™ Fire Barrier Sealant CP 25WB+ is typically used in mechanical, electrical and plumbing
applications to firestop openings created by the following penetrations in fire-rated floors, floor/ceilings or walls: metallic
pipe, plastic pipe (excluding CPVC), conduit, power and communication cable, cable trays, busways, combos, insulated
pipe and HVAC duct penetrations 3M™ Fire Barrier Sealant CP 25WB+ is also used to firestop blank openings and static
construction joints."

Here's a Hilti spect sheet on firestopping:

https://www.hilti.com/medias/sys_ma...90/CAD_BIM_Typicals_ASSET_DOC_LOC_1577645.pdf

What exactly is the inspector citing as the issue? Your words seem to suggest that CP25WB isnt rated for application on steel stud.

Hilti FS1 is what we always used, we've used it for ENT going thru steel stud. Never had an inspector ask if we were certified, nor even check the tubes to see if the expiration date had passed.

I'm pretty sure Hilti will sell their firestop products to anyone. If you want to be an accredited firestop contractor, they offer courses for that, but I have never heard of them being required.

I am in the middle of a project that consists of steel stud framing using all MC / conduit methods and now have a hiccup.

The friendly inspector informed me that we have been incorrectly using firestop (3M CP25WB+) to seal our penetrations through the steel top plate. He is of course correct in this observation, my question is do you all know of any firestop / draftstop (different areas) product that I could use to seal a 3/4" - 1" hole containing MC cable.

I am trying not to resort to pulling cables out and placing sheetrock in the cavities, securing sheetrock, drilling holes, replacing cables and then applying firestop. I have been told there is a Hilti product that I could potentially use, but you have to be Hilti certified to apply it...

And yes, now that I have done further research I see now it was a bonehead move. Not that it matters, but we have done it for years and every other inspector has been wrong in approving it.

I'd bet the other inspectors have been correct and this one is wrong rather than the other way around.

I would call 3M first thing in the morning.

 

[greenwoodpatriot]

The issue is the adhesion and ability to get the UL's bead depth requirement on steel framing.

I have spoken with another manufacturer who says that he cannot provide a UL sheet that approves their firestop for a steel stud top plate; only wood and drywall. I have also spoken with someone at 3M who also cannot provide a UL sheet showing steel framing. I will give Hilti a call to see if they can give more guidance on the product a colleague was speaking of.

Thanks for the input.

 

[luckylerado]

...seal our penetrations through the steel top plate....

So you have rated partitions that do not go all the way up to the deck above? I find this very odd.

...you have to be Hilti certified to apply it....

This would be a spec issue or a local AHJ requirement. If certification is required, there are plenty of alternatives product lines that offer free online "certification" (Those are air quotes and are meant to be pronounced with a fair bit of sarcasm). Hilti will send a rep out to certify you as well if you spend enough money with them.

 

[roger]

So you have rated partitions that do not go all the way up to the deck above? I find this very odd.

Same here. I would like to hear more about the particular building or project that requires more than draft stopping the top plate.

Roger

 

[dkidd]

"Applications
High-performance 3M™ Fire Barrier Sealant CP 25WB+ is ideal for sealing single or multiple through penetrations in
fire-rated construction.

As OP describes it, it is a penetration of a metal top plate that is not part of a fire rated assembly. That said, more detail would be helpful, such as why the penetrations need to be sealed, what building code reference.

 

[kwired]

As OP describes it, it is a penetration of a metal top plate that is not part of a fire rated assembly. That said, more detail would be helpful, such as why the penetrations need to be sealed, what building code reference.

Sounded that way to me as well, top plate with no additional covering is not going to be rated for any more then 15 minutes in the first place I would think.

 

[steve66]

I think we are all thinking the same thing.

You usually only have to fire stop when you are putting holes in the drywall. Even then, a certain number of electrical boxes is usually allowed.


UL has a fire resistance assembly directory:

http://www.ul.com/wp-content/uploads/2015/06/FR-assembly-searches.pdf

 

[Strathead]

The issue is the adhesion and ability to get the UL's bead depth requirement on steel framing.

I have spoken with another manufacturer who says that he cannot provide a UL sheet that approves their firestop for a steel stud top plate; only wood and drywall. I have also spoken with someone at 3M who also cannot provide a UL sheet showing steel framing. I will give Hilti a call to see if they can give more guidance on the product a colleague was speaking of.

Thanks for the input.

With regards to the posts others have made, I suggest you research the wall itself. IF it is a rated assembly (like others I don't believe it is) then there is a detail or a reference to a typical detail of the assembly that was tested. From there it should be a hop, skip and jump, to find a product that will seal holes. Otherwise the listed assembly probably doesn't even allow holes.

 

[KnightPower]

Why not 3M Fireblock foam? Its listed to adhere to metal and what I use personally. Its also cheaper than fire caulk in my experience. Of course the others have a point in whats going on with the assembly. But if its one of those "lets get this passed and move on" moments thats what I would do.

Sent from my SM-N900P using Tapatalk

 

[JFletcher]

So you have rated partitions that do not go all the way up to the deck above? I find this very odd.

Me too. In our cases, the steel stud top plate was against the concrete slab for the floor above. I suppose one could have a rated wall with the steel stud top plate going up to open trusses.

Minimum depth of fill may not be required if the annular space is within specs. If a depth of fill is needed, I dont see why 1/2" or 5/8" drywall board, say a 4" x 4" piece, couldn't be drilled, then cut in half and installed around the existing MC cable. Or use a putty brick or the like. I'm sure 3M, STI and/or Hilti have products to retrofit existing installs without removing cable or conduit.

Steve66, are you thinking of this?:

http://www.fireretardantsinc.com/putty/pdf/3m_putty_pads.pdf