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Joined: Jan 2005
Posts: 5,360
Likes: 1
Cat Servant
During our work we often have to make holes through walls, top plates, fire blocks, etc.

Now, we all "know" about the red caulk, and fire-rated walls. But what about the family home? Do we seal where the romex gos through the fire-blocking? How? Just any old caulk? A little expanding foam?

More to the point- where do we find exactly what 'the code' requires?

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Joined: Jul 2004
Posts: 9,766
Likes: 13
Certainly this is up to the AHJ but the interpretation I have see in SW Fla is this is not a fire rated assembly in R3 unless you are talking about a garage with living quarters over it.
Foam is the usual fire stop material. I have heard a lot of discussion about foam. Some of it is nasty in a fire. (smoke and dripping fire)
They may reevaluate it soon.

Greg Fretwell
Joined: Feb 2005
Posts: 219
In my area the Insulation Contractor is responsable for sealing all holes created by the subs work.
so...we do not worry about it.
This applies to resi work only.

Joined: Dec 2004
Posts: 209
In my area, we need to firestop "large" holes. These are up to the descretion of the inspector, but we usually stuff rockwool around pipes and ducts. The holes from wires are ignored. If I'm trying to cut down on the draft created by them, I'll use latex caulk or the white foam that stops expanding once it is in the hole.

Joined: Jan 2005
Posts: 5,360
Likes: 1
Cat Servant
I always "knew" that holes could be patched by using the same methods and materials as were used in the original construction. For example, you could patch a hole in sheetrock with joint compound- it wasn't necessary to use the red caulk, or any other special product.

The challenge was in documenting what I "knew." Well, I found it....

NEMA, in co-operation with UL, conducted a study that documented this, and other, practices.

"Annular Space Protection of Openings Created by Penetrations of Tubular Steel Conduit- A Review of UL Special Services Investigation File NC546 Project 90NK11659"

This summary, as well as the full report, are available from NEMA.

"Anyone can have an opinion- but DATA is what makes one opinion stand out from the pack!"

Joined: Dec 2003
Posts: 751

could you be more specific? I tried searching NEMA's website no no avail.

In reference to the residential fire caulking, the IRC is a bit more specific:
Fireblocking is required "at ceiling and floor level, with an approved material to resist the passage of flame and products of combustion."
We all know that "approved" means acceptable to the inspector, and what is acceptable to all inspectors is a listed product used in accordance with that listing. Or, in other words, red caulking.

Joined: Mar 2007
Posts: 25
when wiring any structures whether its a wood house or a high rise in northern virginia, maryland and washington d.c. we must firestop -any -penetrations that go from one floor to the next or through any fire rated walls with rockwool or fire caulk. even small ones such as holes for romex,mc,emt,rg6 and cat5. the electrical inspector enforces this and will fail you for it. as well as any fire mashall or building inspector

Joined: Dec 2004
Posts: 209
Well...we just got rejected on a concealment inspection on this very issue. Our inspector wants the red fire-rated caulk used to fill holes around the electric wires and other small holes. I was told they just started enforcing this in residential construction in my area.

Joined: Mar 2007
Posts: 49
You need to read the UBC and not just the NEC.

In fire rated walls boxes must be mounted to the studs, (no "cut-in" boxes unless maybe you can cut them in next to and mount them to the stud instead of useing "hold-it" clips) Boxes in opposite wall faces must be at least 24" apart center to center. (to insure that they aren't in the same stud space.)

The UBC also specifies the sealing methods around penetrations in fire walls. You won't find an article in the NEC to qoute or to dispute with the inspectors. If you want to be informed you will also have to be familiar with the UBC codes.

No I'm not trying to be a smart aleck....just stateing a fact. It takes more than NEC knowledge to perform and comply as a proffessional nowadays.

Joined: May 2002
Posts: 1,716
Ausador, the wording used by the UBC for mounting boxes in rated walls is from the UL orange books, so it can be found there or on the UL web site with out the need to own UBC literature.


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