ECN Forum Forums Code Related Discussion NEC & other Code issues Seal up the holes

The 2000 International Residential Code requires a fire block: "At openings around vents, pipes, and ducts at ceiling and floor level, with an approved material to resist the free passage of flame and products of combustion."

What makes a material "approved" is that it is acceptable to the building official. Some may approve mineral wool, others tightly packed fiberglass, but all inspectors will accept the listed fire caulking (when installed according to that listing).

I find it interesting that cables are not specifically listed as requiring fire blocking, but it is universally enforced as requiring fire blocking.

When spray foam is used (for simple non-fire proof draft stopping), are there any issues with the solvents or blowing agents damaging the cable insulation?

Are there any listed foams that are specifically designed to work with electrical insulation?

-Jon

I am not aware of any foams made specifically for use with electrical wires. As far as I know, UL only tests such products as their use pertains to fire-rated assemblies.
UL has other standards that relate to flamability- and you can be sure none of the foams pass, as they all burn like rocket fuel. (As a historical note, it was the use of such foams, and their ignition by a plumber checking for drafts with a candle, that led to a nearly disasterous fire at the Browns' Ferry Nuclear Plant in the '70's....and which in turn spurred the development of the fire-resistant caulks we now use.)

The foams are mostly made of a urethane resin and catalyst, which reacts with water in the air to form a urethane foam. Crumbly as they seem, urethane is considered a syntheyic rubber. There really aren't any "solvents" as such involved. As urethane is itself used as electrical insulation (that red varnish on motor windings is also urethane), I don't see any risk here.

There is, of course, no reason you can't seal the hles the old-fashioned way, with joint compound, mortar, or plaster.

As earlydean said, the 2000 IRC requires fireblocking at certain areas. It also list products used for firestopping. Firecaulk is not one of them as it is an overkill. In residential we are usually dealing with wood studs, wood joists, wood subfloor, wood sheathing...see a pattern here? The basic idea is to stop the air from going thru the holes for as long as it would take to burn thru the wood. Rockwool is the draftstop of choice in this area.

To sort of recap some of the discussion, and to add some "Code-Weenie" input:
George, your key work there is "non-fire rated".
Looking at the Int. Bldg. Code (IBC) ch. 7, we see the distinction between "fire-stopping", which is use of tested/listed materials or products as part of a fire-rated assembly. Where, and how, and what, are discussed in IBC ch. 7. IF you're having trouble sleeping, it makes a good read!
IBC sec. 717.2 requires "fireblocking" to cut off fire travel from wall cavities to floor and roof cavities above, and from floor cavities below to wall cavities.
717.2.1 lists materials, all of which have been used for decades: 2x blocking, drywall, plywood, particleboard, or batt insulation. Note that this stuff isn't air tight 100%. It's not "rated". not tested or listed. It just makes it really hard for fire, or hot gas, or smoke, to progress from space to space. The bottom of the code section paragraph says "... to retard the spread of fire and hot gases".
2 cents done.

Thanks, all, for a great set of forums.

What is required in the top and bottom plate is a fire stopping. The only wall in a residence that is fire rated is the wall between the residence and garage. There I would require a ul listed product such as duct seal. George what do you require in the through penitrations of the cold air return? (Horizontal)

Actually, the wall between the house and the garage is not a rated wall. The IRC only requires it to be 1/2 inch sheetrock, and 5/8 inch type X for ceilings of garages where habitable spaces are above. (also, if the ceiling separates the garage from a habitable space, then the exterior supporting walls also need 1/2 inch sheetrock.)

The only rated wall required in residential construction is the wall separating individual dwelling units of two and multi-family buildings. This "party" wall must have a 2-hour rating, commonly achieved with 2 layers on each side of 5/8 inch type X sheetrock.

The IRC also makes it clear that wood or sheetrock cannot be used for the fireblocking requirement around pipes and cables. Only "approved materials" can be used.
The commentary calls the material "firestopping", the code text requires "fireblocking". I think the terms are interchangable.

I may have mis spoke. The penetrations top and bottom is not called firestopping but draft stopping. That is what I recall from my residential days.

Firestopping/blocking is very specific in nature.
I went to a state sponsered course a week ago, and I am taking a class on Tuesday. When I am finished with the class, I will relate some info here. My eyes were opened at the State course, and I hope to have a more thorough understanding after Tuesday.

NYS is heading in the direction of having certification for the installer of firestopping. I mentioned this before, and some got upset. The reality is that there are many installations that do not meet the minimum installation requirements, and the authorities are aware of this.