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Joined: Mar 2005
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This looks to me like a hack "pro" did the work. No DIY would waste good wire like that. And the framing and concrete look professional- they use pressure treat where they need to, proper tie-down bolts, looks like the right fastener schedule was used, etc. Pity they'll have to come back and replace so much of it to pass the framing inspection. Plumbing looks pro, too. Doesn't recessing those panelboards in the wall separating the garages pretty much kill any fire ratings that they would otherwise have? Here in the US; interior garage walls would need a 2-hour fire rating to keep a fire in the garage from spreading to the house. No, recessing the panelboards like that is OK under IBC/IRC. The sheet metal housing acts as a firestop. Same goes for HVAC- it's OK, so long as the penetration is metal. So, ductboard in the garage, metal take-off punched through the drywall, transition to flex just inside the wall = OK. Plastic boxes with plastic covers are surprisingly OK as well, I guess 4" holes aren't the fire risk they may appear to be. You have to figure that not only is there 5/8" type-X gypsum wallboard, the walls are also packed full of firestopping fiberglass insulation. It's not intended to stop a fire, or stop the spread of fire, just allow enough time for the occupants to escape before the house collapses.
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Joined: Jan 2005
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Sorry, Steve, but I have to differ. First, though, I'll return to Norcal's question.
It's a very common requirement that there be a firewall in two circumstances: buildings adjoining each other ... and between the garage and living spaces. In both situations, a 1 hour rated wall is usually what's called for.
Now, that 1 hr. rating is pretty easy to achieve. Two layers of 5/8 drywall will do it .... and the layers need not be on the same side. That's why you often find garages with drywall only on the 'house' side, and a double layer on the ceiling (when there are rooms above the garage).
In a duplex building, the two garages usually do NOT need a 1 hr wall between them, as long as the walls between the garages and the units qualify. There are actually some duplexes where there is no wall between the two parts of the garage.
Otherwise, in the industry's standard fire test of wall assemblies. penetrations do matter. That's why you're supposed to place the boxes for either side in different stud bays. (Code language is actually 24" apart). The dividing line for size is 16 sq. inches .... leading to some debate as to whether your typical 4-square box requires you to use the putty pads. (Generally, the answer is 'yes.')
Fiberglass insulation may not burn very well, but it does nothing for the fire rating of a wall assembly. Let's not confuse the rating of the wall assembly with simple draft stopping.
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Joined: Jul 2004
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What is going in the 2x4 box mounted on the bottom of the disconnect box?
Larry C
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Joined: Mar 2005
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If there are bedrooms above the garage, all structural walls must be firestopped, even the exterior ones, to prevent structural failure. Also, properly packed fiberglass insulation is an approved firestop per IRC: R602.8.1 Materials. Except as provided in Section R602.8, Item 4, fireblocking shall consist of 2-inch (51 mm) nominal lumber, or two thicknesses of 1-inch (25.4 mm) nominal lumber with broken lap joints, or one thickness of 23/32-inch (19.8 mm) wood structural panels with joints backed by 23/32-inch (19.8 mm)wood structural panels or one thickness of 3/4-inch (19.1 mm) particleboard with joints backed by 3/4-inch (19.1 mm) particleboard, 1/2-inch (12.7 mm) gypsum board, or 1/4-inch (6.4 mm) cement-based millboard. Batts or blankets of mineral wool or glass fiber or other approved materials installed in such a manner as to be securely retained in place shall be permitted as an acceptable fire block. Batts or blankets of mineral or glass fiber or other approved nonrigid materials shall be permitted for compliance with the 10 foot horizontal fireblocking inwalls constructed using parallel rows of studs or staggered studs. Loose-fill insulation material shall not be used as a fire block unless specifically tested in the form and manner intended for use to demonstrate its ability to remain in place and to retard the spread of fire and hot gases. R602.8.1.1 Unfaced fiberglass. Unfaced fiberglass batt insulation used as fireblocking shall fill the entire cross section of the wall cavity to a minimum height of 16 inches (406 mm) measured vertically. When piping, conduit or similar obstructions are encountered, the insulation shall be packed tightly around the obstruction. R602.8.1.2 Fireblocking integrity. The integrity of all fireblocks shall be maintained. Proper insulation is required in IBC for the fire rating of walls, too, but I believe it's more for thermal insulation purposes. IBC is pretty specific about it in the one table. Also, fiberglass does not burn. It's glass! It's rated to 1000F, also. The ill-conceived tuft-test that's always referenced is bogus; repeat the experiment with a full batt and you'll see that the lighter does nothing but leave a little carbon residue.
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Joined: May 2003
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Thanks for the clarification Steve. 
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Joined: Jan 2005
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Steve ... you're continuing to mix apples with oranges. Firestops and fire rated walls are two entirely different topics.
"Firestopping" is simply closing a cavity. Period. We can discuss different ways this is done - but it has nothing at all to do with how well a wall will perform preventing a fire from passing through the wall - either directly, or by getting hot enough to ignite what's on the other side.
Fiberglass doesn't burn? While is is usually classed as 'non combustible' in surface burning tests, I assure you I can light a piece with a torch. I can also make steel wool burn vigorously. But, we're talking about 'fire walls' here, not parlor tricks.
I doubt the IRC, or any other code, would require a particular wall construction. I would expect them to want you to use a 'rated assembly.' That is, assemblies that have been subjected to full scale, industry standard, fire testing. UL publishedsa 'fire resistance directory' that is one of the more common atlases of rated designs. There are others, as well. A review of many different designs, comparing the same design with fiberglass batts to one without, shows absolutely no difference in the rating achieved. Insulate if you will, but don't do it to achieve greater fire resistance!
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Joined: Sep 2002
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What is going in the 2x4 box mounted on the bottom of the disconnect box?
Larry C Access to the Ufer.
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Joined: Jul 2004
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The 2x4 box I am refering to has a cover on it, and is visible in the rear view of the building disconnect panel. I don't see any rebar coming up thru the foundation. I thought it might be for a convience outlet but I didn't see any location for the circuit breaker in the Service Entrance.
Larry C
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Joined: Sep 2002
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It's been set up for temp power, the box you are asking about is a GFCI receptacle, the rebar is behind that former 2 gang "box".
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Joined: Mar 2005
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Panels next to each other. Is that the fire seperation wall between the two units ? Junk wiring.
Alan-- If it was easy, anyone could do it.
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Posts: 43
Joined: September 2013
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