Sheet metal wall shield reduces clearance requirement by how much?

[Intheswamp]

It seems that somewhere (I think in a thread of mine, maybe) that I picked up the notion that a 24-gauge or thicker metal heat shield with a 1" air-gap behind will reduce the wall clearance by 66%. In other words a required clearance of 36" would be reduced to 12" with a shield of this type. A limitation being that 12" is the minimum that is allowed.

For example, for a listed stove that requires 24" of side wall clearance I could use the above mentioned heat shield and be safe with 12" or greater clearance.

Am I in the ballpark or dangerously wrong?

Thanks,
Ed

 

[begreen]

Essentially correct. Metal gauge is somewhat irrelevant. Aluminum foil would work, but certainly wouldn't stand up too well. Wall shield must also be open, top and bottom.

The manufacturer has the final say. It really helps if they put this into print in the stove manual. Most do. When in doubt, call them up for a clarification.

 

[jstellfox]

I see that most manufacturers post rear and side clearances, but I don't seem to see ceiling clearances mentioned often. I have a 72" ceiling where the stove will be. Its an Englander 30. Perhaps someone here would know what the ceiling clearance for that stove is and if I would need a heat shield on the ceiling? I don't believe I could find it in the manual....

 

[begreen]

Call Englander tech support @ 800-245-6489. I would think a shield would be required for that low a ceiling, but can't say that is the official word. That said, if it was my 6' ceiling I would have a sheet of cement board on spacers above the stove, even if not required.

 

[Intheswamp]

Essentially correct. Metal gauge is somewhat irrelevant. Aluminum foil would work, but certainly wouldn't stand up too well. Wall shield must also be open, top and bottom.

The manufacturer has the final say. It really helps if they put this into print in the stove manual. Most do. When in doubt, call them up for a clarification.

Thanks, BG. If I err, it will be on the conservative side. Most of the manuals give pretty good information, but sometimes they don't. I was looking at the Yosemite and couldn't find the R requirement for the hearth pad...I had to email Quadra-Fire for the info.....R-2.2 .

I've somewhat narrowed down the hunt....more to come.

Ed

 

[begreen]

Essentially correct. Metal gauge is somewhat irrelevant. Aluminum foil would work, but certainly wouldn't stand up too well. Wall shield must also be open, top and bottom.

The manufacturer has the final say. It really helps if they put this into print in the stove manual. Most do. When in doubt, call them up for a clarification.

Thanks, BG. If I err, it will be on the conservative side. Most of the manuals give pretty good information, but sometimes they don't. I was looking at the Yosemite and couldn't find the R requirement for the hearth pad...I had to email Quadra-Fire for the info.....R-2.2 .

I've somewhat narrowed down the hunt....more to come.

Ed

You're right, this is lame documentation:

"The floor must be non-combustible material, extending beneath heater and to the front/sides/rear as indicated. The floor must
be non-combustible or otherwise adequately protected from radiant heat given off by the unit and from sparks and falling
embers. A layer of thin brick or ceramic tile over a combustible floor is not sufficient." - So where is the spec Quadrafire??

R 2.2 is not trivial. Will this be sitting on a full hearth that extends to the basement or would it require a new hearth?

 

[Highbeam]

It seems that somewhere (I think in a thread of mine, maybe) that I picked up the notion that a 24-gauge or thicker metal heat shield with a 1" air-gap behind will reduce the wall clearance by 66%. In other words a required clearance of 36" would be reduced to 12" with a shield of this type. A limitation being that 12" is the minimum that is allowed.

For example, for a listed stove that requires 24" of side wall clearance I could use the above mentioned heat shield and be safe with 12" or greater clearance.

Am I in the ballpark or dangerously wrong?

Thanks,
Ed

Actually, you are dangerously wrong. Only in those cases where the manufacturer specifically lists the use of such a metal heat shield and also lists the corresponding allowed reduction in clearance to combustibles will the heat shield get you anything. You may NOT just reduce the listed clearances by using a heatshield otherwise.

Now if you are somehow using an old appliance without listed clearances then you use the fire code's 36" or so default and then you can benefit from the heat shields as specified in the fire code.

 

[Intheswamp]

Essentially correct. Metal gauge is somewhat irrelevant. Aluminum foil would work, but certainly wouldn't stand up too well. Wall shield must also be open, top and bottom.

The manufacturer has the final say. It really helps if they put this into print in the stove manual. Most do. When in doubt, call them up for a clarification.

Thanks, BG. If I err, it will be on the conservative side. Most of the manuals give pretty good information, but sometimes they don't. I was looking at the Yosemite and couldn't find the R requirement for the hearth pad...I had to email Quadra-Fire for the info.....R-2.2 .

I've somewhat narrowed down the hunt....more to come.

Ed

You're right, this is lame documentation:

"The floor must be non-combustible material, extending beneath heater and to the front/sides/rear as indicated. The floor must
be non-combustible or otherwise adequately protected from radiant heat given off by the unit and from sparks and falling
embers. A layer of thin brick or ceramic tile over a combustible floor is not sufficient." - So where is the spec Quadrafire??

R 2.2 is not trivial. Will this be sitting on a full hearth that extends to the basement or would it require a new hearth?

Could R 2.2 be arrived by building a board with plywood, a couple of sheets of fiber or ceramic board with some mortar and surface tile/stone applied?

The original hearth is a brick/cement structure from the ground up (no basement). The problem is that the stove will actually sit above the current hearth (white tiled area) but there will not be enough hearth in front of the stove....so I'll have to add more to extend out. I figured I'd just build or purchase a hearth pad that butted up against the face of the fireplace, basically creating a new, slightly raised (1"-2") hearth area. Looking at the price of manufactured hearth pads I think I'd like to build one, though I've never played with tile, ceramic boards, etc.,. I've been studying up some on that too.<sigh>

Just for reminders, here's a copy of my hearth area...
http://i111.photobucket.com/albums/n153/intheswamp00/FireboxDimensions2Medium.jpg
I'm thinking of competely covering the white tile and extending the new hearth pad out to the edge of that rug...from what I can tell that would give me a bit over an inch of extra front floor clearance.

With the low venting of the Yosemite building the hearth pad up high shouldn't be an issue in regards to the flue still clearing the lintel.

What'cha think?
Ed

 

[begreen]

If the hearth is solid right down through the crawlspace, it should be ok. But as you mentioned, there's still the ~8" of wood floor that needs protection. If you build an R 2.2 pad it will take an inch of micore or fiberfrax under the 1/2" cementboard and tile to get that insulation value. That will build up the hearth at least 1.75-2"

 

[summit]

install manual should list clearances to protected surfaces and unprotected surfaces... what you are describing qualifies as a protected surface...