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Fireblocks - drilling holes #84614
03/31/03 11:22 PM
03/31/03 11:22 PM
ThinkGood  Offline OP
Joined: Aug 2002
Posts: 1,081
Milwaukee, WI
A neighbor is having a "gut job" done on his house--now it is down to the bare wood.

The contractor is putting in fireblocks in between the existing studs (this is an old house, no fireblocks were used originally) before the electrician comes in to completely rewire the house, before the sheetrock goes up. (By fireblocks, I mean 2x4s that are cut to fit in horizontally between the studs.)

I got to thinking (yeah, I know, thinking can be dangerous)...if the electrician is possibly going to need to drill through fireblocks, doesn't that open a whole can of worms, in that that the fireblock is then compromised? Does the electrician need to seal around the cable to completely fill the hole, or does this apply only to commercial dwellings?

I can't imagine that the guy is going to have to seal every hole drilled vertically yet I find it ironic that an area with electric cable would have holes in the fireblock...

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Re: Fireblocks - drilling holes #84615
03/31/03 11:35 PM
03/31/03 11:35 PM
Bill Addiss  Offline
Joined: Oct 2000
Posts: 3,890

This Blocking is commonly used in the Interior walls. We call them "Cats" (Anyone know why?)

I've never heard of holes through them being an issue but am curious about the requirements for these. I did find something in the NYS Resi Code (which is a modified IRC) Electrical Section, but not sure what it means:

E3302.3 Penetration of firestops and draftstops. Penetrations through fire blocking and draftstopping shall be protected in an approved manner to maintain the integrity of the element penetrated.


[This message has been edited by Bill Addiss (edited 03-31-2003).]

Re: Fireblocks - drilling holes #84616
04/01/03 12:21 AM
04/01/03 12:21 AM
CTwireman  Offline
Joined: Feb 2002
Posts: 840
Connecticut, USA
Here in Connecticut we are required to fill these holes with fire stopping (retarding?) compound.

Re: Fireblocks - drilling holes #84617
04/01/03 02:50 AM
04/01/03 02:50 AM
nesparky  Offline
Joined: Jun 2001
Posts: 642
see 300.21
A lot of places say if you drill it you seal it.

Re: Fireblocks - drilling holes #84618
04/01/03 03:24 AM
04/01/03 03:24 AM
lwinter31  Offline
Joined: Nov 2002
Posts: 40
This is really not a big issue here. 2 to 4 vertical pulls per room max to seal. The just of cable in walls is pulled horizontally in residential installs.

Bill ? - CATS=(Cuss At Them Suckers)?

Re: Fireblocks - drilling holes #84619
04/01/03 07:08 AM
04/01/03 07:08 AM
Redsy  Offline
Joined: Mar 2001
Posts: 2,056
Bucks County PA
We are regularly required to "fire caulk" penetrations that separate 2 floors. The caulk can cost $10-15 per tube.

Re: Fireblocks - drilling holes #84620
04/01/03 08:17 AM
04/01/03 08:17 AM
ThinkGood  Offline OP
Joined: Aug 2002
Posts: 1,081
Milwaukee, WI
Thanks for the quick response.

nesparky: 300.21 -- That's the one I remembered but couldn't find.

I've never noticed any kind of caulking, etc. in the photos here (and elsewhere) that show Romex through holes. (OK, many of the photos here are posted to show violations anyhow :eek [Linked Image] nor have I seen it in the few newly-built houses I have seen.

I did find the caulking online--one site had it for about $9 per tube.

Interestingly enough, I found some articles (via Google searches) that stated that fiberglass insulation, when the barrier material is covered, is better than wooden fireblocks.

lwinter31: Your explanation of "cats" sounds very plausible [Linked Image]

As usual, you folks gave great information.

Re: Fireblocks - drilling holes #84621
04/01/03 09:07 AM
04/01/03 09:07 AM
Electricmanscott  Offline
Joined: Jan 2002
Posts: 1,457
Holden, MA USA
Here in MA I beleive you are required to seal penetrations between floors. Not 100% sure though, general contratctors usually do this.

Re: Fireblocks - drilling holes #84622
04/01/03 01:51 PM
04/01/03 01:51 PM
pwood  Offline
Joined: Feb 2003
Posts: 67
castella,calif usa
fireblocking required in walls at ten foot intervals.fireblocks required at blocks required at stair stringers.a dab of fire caulking at the penetrations is sufficient if the product is listed that way.if the fireblocks are not code required no protection is required.

Re: Fireblocks - drilling holes #84623
04/01/03 05:46 PM
04/01/03 05:46 PM
ken m  Offline
Joined: Aug 2001
Posts: 58
south carolina
here in s.c. the blocks are called perlins or perliners (sp) they are only required in interior walls that exceed 8' in height. the requirements are to use the mortar or caulk in the top and bottom plate not the perlin and of course that depends in which county the job is located. ken m

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