I have a home owner who wants his breaker panel on the wall between the garage and the house only. As this is a firewall, I can not find much info in the code on it. Only 300-21. Am I missing something? The way I read it, all I need to do is apply a firestop product around the wire holes. This doesn't seem like enough to me.
sparkie, i beleive there are different levels of classifications of firewalls, ranging from 1 hr burn ,to a distinctly separate building. what can penatrate, or exist in the same bay follows suit. anyone here have this particular code??
Re: Firewall#78296 09/04/0106:59 AM09/04/0106:59 AM
There is a limit to how much total area is allowed to be comprised of openings on one side of a wall in relation to total area of wall space. The ratio escapes me now,(I believe it it 100 sq. in. opening per 10 sq. ft. of wall space) but I'll check when I get home. Also, remember that back-to-back openings are not allowed in the same stud bay, unless certain guidelines are followed, as well. I'm sure someone else on this site wil know.
Re: Firewall#78297 09/04/0107:43 AM09/04/0107:43 AM
f) Membrane Penetrations. Walls may have openings for steel electrical outlet boxes not exceeding 16 square inches in area ,provided the aggregate area of such openings is not more than 100 square inches for any 100 square feet of wall or partition area . Outlet boxes on opposite sides of walls and partitions shall be separated by a horizontal distance of at least 24 inches . Where wall-protective membranes are penetrated by other materials or where larger openings are required than permitted above, the penetrating items shall be:
1. Protected with membrane-penetration fire stops suitable for the methods of penetration.
2. Installed in accordance with the installation instructions of their listing for such use.
EXCEPTION:Penetrations not larger than a 4-inch nominal pipe or 16 square inches in overall cross-sectional area containing noncombustible penetrating items, where the annular space between the penetrating items and the protective membrane being penetrated is filled with a material which will prevent the passage of flame and hot gases sufficient to ignite cotton waste when subjected to U.B.C. Standard No.43-1.Time-temperature fir conditions under a minimum positive pressure differential of 0.01-inc water column at the location of the penetration for the time per
Checking with the AHJ is the best answer because there could be other factors involved like.. is that an acceptable location for the panel. If it is going in the wall a generally accepted way of maintaining the raiting is a drywall box out. Maintaining required air space between layers. Being a house and probably a 3-1/2" studwall, with a box out it will end up a semi-recessed panel.
Here is the language out of the 200 IRC. It's almost identical to the lamguage in 1995 CABO.
R309.2 Separation required. The garage shall be separated from the residence and its attic area by not less than 1/2-inch (12.7 mm) gypsum board applied to the garage side.Where the separation is a floor-ceiling assembly, the structure supporting the separation shall also be protected by not less than 1/2-inch (12.7 mm) gypsum board or equivalent.
Notice that at no time does the code use the term "firewall" in describing this wall/ceiling.
I thinking that this is not truely a fire all in the truest sense of the definition.
The spec that Nick has provided is the one that I've been accustomed to using, although I haven't done much resi work for years. When we have to flush mount anything larger than a quad recp or double switch, it must be "boxed out" with drywall so that it actually lies in a recess that is outside the firewall's envelope.(usually a big pain). When possible,(unless it will project objectionably into a fire corridor or the like) we surface mount panels and such, and for aesthetic purposes will furr out and drywall around them.