ECN Forum Forums Code Related Discussion NEC & other Code issues sealing drilled penetrations(residential)

Different areas have different practices.

Doug & jps 1006: Do you have someone drill holes for you too?

Some here are getting this confused with fire rated wall construction. The requirement to seal holes drilled in plates and studs is not limited to fire rated walls. Section R602.8 in the IRC requires fire blocking in various locations. The UBC and IBC have similar requirements. Among other places, the IRC requires fire blocking:

1. In concealed spaces of stud walls and partitions, including furred spaces and parallel rows of studs or staggered studs: as follows:
1.1 Vertically at the ceiling and floor levels.
1.2 Horizontally at invtervals not exceeding 10 feet

In a typical wall, the studs and the top and bottom plates also serve as the required fire blocking. Section R602.8.1.2 Requires that the integrity of all fireblocks shall be maintained. If holes drilled in top or bottom plates would allow fire to pass through, then the integrity of the fire blocking has been compromised. If holes drilled in studs would let fire spread for more than 10 feet horizonally, the same would be true.

[This message has been edited by eprice (edited 08-09-2005).]

eprice- I agree with you on your statement with respects to the IRC. We have the MRC here in Michigan and it is basically the IRC with the Michigan twist on it. The issue we have run into is that we still have inspectors who insist that the contractors use fire rated material (fire caulk) when it is rather obvious that since it is not a fire rated wall or assembly that a fire rated material is not necessary. There are several cases in the IRC/MRC that address using fiberglass insulation as a fire blocking material. To lazy to give code references but I can and will if someone is interested.

George,

Yes, I agree. And I have spoken with a representative of ICC about this. No official interpretation, so take it for what it is worth, but the individual I spoke with concurred that fire caulk is not required when the only issue involved is maintaining the integrity of fire blocking. He stated that expanding foam would not be acceptable because it is too insubstantial, and I would add, burns too well. But a good silicone caulk, or as you say, fiberglass insulation would work. I have seen some expanding foam that is fire resistant. I think this would be acceptable as well. How do you feel about that?

I don't see a problem with fiberglass insulation- properly installed so it stops air flow and don't fall out. I'm from the days when we used to use asbestos cement to "firestop" and when the drywall guys were nailing drywall you could count on the dried out cement falling out so you'd end up with no blocking what so ever. Using fire caulk in a combustible structure is like killing a fly with a 12 gauge shotgun.

We had a seminar about fire rated assemblies and one of the main points they made was simply squirting fire caulk in a hole does not make this a firewall. It needs to be part of an engineered fire rated assembly or you are just wasting caulk.