Garage Fire Separation At Furnace Closet

Robert Autrey · 02-25-2009, 09:09 AM

I don't encounter many furnace closets in garages, but I did yesterday. The closet has a hollow core door and the supply duct passing into the attic of the living space is not metal (just duct board). Should the closet door be a fire rated door? Should the supply plenum/duct passing from the garage closet into the attic of the living space be metal? Both? Neither? I've attached photos of the closet location, the door and the duct.

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**Jerry Peck** · 02-25-2009, 09:23 AM

Originally Posted by Robert Autrey

The closet has a hollow core door and the supply duct passing into the attic of the living space is not metal (just duct board).

Should the closet door be a fire rated door?

Not necessary as the *separation* (not "fire separation, there is no fire rating for it) is provided by the gypsum on the walls of the closet.

[quote]Should the supply plenum/duct passing from the garage closet into the attic of the living space be metal?[/quote[

Yes, because it is considered inside the garage with that hollow core door.

Both? Neither?

Either.

IF the door were to meet the requirements for a separation door and be weatherstripped and have a threshold, then the closet may be able to be considered outside the garage space, in which case the duct would not need to be metal.

IF the door is left as is, then everything in the closet must be as required for being in the garage - metal duct, seal around everything, etc.

Also not that there is no secondary condensate drain line for the AHU, and no trap for the primary condensate drain line.

That should do for starters, probably other things wrong too if you looked closer.

Robert Autrey · 02-25-2009, 09:33 AM

Originally Posted by Jerry Peck

Either.

Thanks for your input Jerry.

I failed to mention, I found a wafer board fire separation in the attic between the garage and the living space. It has a pretty big hole in it for electrical wiring to pass through. I've always seen gyp board here. Does wafer board qualify? I'm thinking not. It seems to me that this is just more fuel.

**Jerry Peck** · 02-25-2009, 09:52 AM

Originally Posted by Robert Autrey

Thanks for your input Jerry.

I failed to mention, I found a wafer board fire separation in the attic between the garage and the living space. It has a pretty big hole in it for electrical wiring to pass through. I've always seen gyp board here. Does wafer board qualify? I'm thinking not. It seems to me that this is just more fuel.

First, it is not "fire separation" there is no fire rating to it, it is simply just "separation", and, no, OSB is not approved for that use, if that was intended to be the "separation" wall continued up from the garage / living space wall, then it would need to be covered with gypsum board and it would need to be sealed around all the NM cables going through it - which makes sealing around a large group like that next to impossible, so the best way if one or two NM cables per hole and seal around them in small groups.

IF that wall was gypsum board, and IF that wall was directly above the garage house wall, and IF the closet was on the house side of that wall, and IF the closet had the proper door/weather stripping/threshold, ... then the garage ceiling would not even be needed as the "separation" would be provided for by that wall ... providing all the IFs were done.

Robert Autrey · 02-25-2009, 10:04 AM

Originally Posted by Jerry Peck

IF that wall was gypsum board, and IF that wall was directly above the garage house wall, and IF the closet was on the house side of that wall, and IF the closet had the proper door/weather stripping/threshold, ... then the garage ceiling would not even be needed as the "separation" would be provided for by that wall ... providing all the IFs were done.

That's what I thought. The wall in the attic is directly above the wall separating the garage from the living space and the garage ceiling is covered with 1/2-inch gyp board, but the disappearing stair at the garage ceiling is not a fire rated unit. It has a 1/4-inch plywood closure that is not stamped. I'm thinking they need to either install a fire rated stair, or bring the attic separation into compliance.

**Brandon Whitmore** · 02-25-2009, 10:08 AM

Just to simplify things...........

There appears to be drywall (gypsum board) on the garage ceiling; if that is the case, drywall is not necessary on that attic wall. (assuming drywall is properly detailed on the ceiling).

**Jerry Peck** · 02-25-2009, 01:14 PM

Originally Posted by Robert Autrey

That's what I thought. The wall in the attic is directly above the wall separating the garage from the living space and the garage ceiling is covered with 1/2-inch gyp board, but the disappearing stair at the garage ceiling is not a fire rated unit. It has a 1/4-inch plywood closure that is not stamped. I'm thinking they need to either install a fire rated stair, or bring the attic separation into compliance.

You keep saying "fire rated" and it is not a "fire rated" wall, nor does the stair need to be a "fire rated" stair.

It is simply "separation", nothing more, nothing less. Yes, a "fire rated door" IS ALLOWED as an option in the wall to the house, but it is not required.

The only requirement is to maintain the "separation" by use of the 1/2" gypsum board.

Yes, the stair *could be replaced* with a "fire rated stair" which would solve the problem, or, one could build a box up around the stair and place a piece of 1/2" gypsum over it, or, if not dis-allowed by the manufacturer of the stair, one could simply attach a layer of 1/2" gypsum to the bottom of the stair covering.

Or, yes, that wall could be covered with 1/2" gypsum and have all the openings through it sealed.

The first thing to do thought, the very first thing, is to stop referring to that as "fire rated" anything. The IRC does not call for any "fire rating". I believe the California code may, but there are not many which do.

*IF* it were "fire rated" then that would require (one option) 5/8" Type X gypsum board on BOTH sides of the wall separating the house from the garage, as well as on the ceiling. But it is not and does not.

**Jerry Peck** · 02-25-2009, 01:15 PM

Originally Posted by Brandon Whitmore

Just to simplify things...........

There appears to be drywall (gypsum board) on the garage ceiling; if that is the case, drywall is not necessary on that attic wall. (assuming drywall is properly detailed on the ceiling).

Except for the pull down stair ...

Except for the non-metal duct at the air handler unit which is "in" the garage with that hollow core door ...

Except for ... all the other things we mentioned.