clearance to combustables question

[stovepipe?]

is the 18 inch clearance on single wall pipe to combustable materials or to the surface of any non-NFPA compliant surface. I have (just barely) 18 inch clearence to wooden studs (I had to take down the plaster to put in the thimble). I am about to replace the wall with cement board. To keep it flush with the rest of the wall, I can get a 1/2 inch spacer in there, but not a 1 inch. the studs are around the chimney, so there is plenty of airspace around them. When it's all said and done I will have just under 18 inches from pipe to the studs, and just under 17 to the wall surface.

Other question: the requirments for my jotul stove indicate that with single wall pipe, the stove itself has to be 25 inches from combustables. With double wall pipe or pipe w/ heat sheilds, it is 10 (stove comes with a built in heat shield). Does this make sense? If I can achieve the 18 inch clearance w/ my stovepipe, isn't this the only limiting factor? why can't the stove sit 15 inches off the wall so long as stovepipe is 18?

thanks in advance

 

[BrotherBart]

We need some more information here. The clearance problem you talk about sounds like you have a F3CB and want to vent from the right or left side. Otherwise if you were venting rear horizontal or top vertical I don't see how you would have this question.

A little more detail please.

 

[stovepipe?]

that's right, a Jotul F3CB. I want to vent from the top. the wall I'm talking about is behind the stove. THe back edge of the stove is about 4 inches closer to the wall than the pipe when rising vertically out of the top vent.

thanks

 

[BrotherBart]

Then you are fine. The Jotul manual specs are taking the distance from the pipe to the back of the stove into consideration. Therefore, if a double wall pipe is rising straight up vertically out of the stove and the back of the stove (with the heat shield installed on the stove) is ten inches or more from the wall, you are fine.

Ten feet is better, but you are within Jotuls clearance guidelines to combustibles.

 

[stovepipe?]

for various reasons, though, I am wanting to use single wall pipe. That's why I'm asking about the 18 inch clearance.

thanks.

 

[BrotherBart]

Ya can't do it because that bare pipe gets one hell of a lot hotter than the back of the F3 with the heat shield. I went the same route with my first stove, an old Franklin. I only built the brick behind it up to where the pipe came out of the top of the stove. I like to have burned the house down one night when the pipe heated up the wall behind it.

You are not going to believe the heat that pipe radiates at full burn. I know. There is an F3CB with single wall burning in my basement right now. With a concrete block wall behind it.

 

[begreen]

Similar setup, but we have windows about half-way up. So I have a heat shield on the window side of the pipe all the way up to the thimble. This seems to work very well and helps us recoup a bit more heat from the stack. You can see the heat sheild on the pipe here:
https://www.hearth.com/econtent/index.php/forums/viewthread/13/

 

[annette]

I checked out the manual of the F3 CB. You should too! Go to http://www.fireplacesonline.com/jotul/pdf/manual/wood/F3CBmanual.pdf. Read pg 11 of the manual itself.

It says that if you are using single-wall pipe with the rear heat shield, your back clearance is 25 inches. It might make sense that it should be 18', since it seems that the single-wall pipe is dictating the distance, and some (all?) single-wall pipe has a clearance of 18 inches. But, the important thing here is that this is the clearance dictated by the manufacturer, and for a reason!

You said that you have reasons for wanting to use single wall. Why won't you use a pipe shield? You already know that it will reduce your rear clearance to 10 inches.

You mention replacing your sheetrock with cement board. Installing it according to the NFPA code with the 1-inch spacers and proper airflow will give you a smaller clearance. It will reduce it to 14" if you use single wall with no pipe shield, and 6" if you have both the cement board wall and the pipe shield. So don't worry about maintaining 18" or 17 3/4" or whatever you'll get with your smaller spacers, because installing it according to code (including to the right height) means your clearance is now 14" or less.

 

[Nokoni]

Hey Be Green, nice setup, what are the walls behind your stove? Do they get super hot?

 

[stovepipe?]

thanks to all for the input.

BeGreen-- what is your clearance behind your stovepipe? How well do those heat shields work? Do you have a sense of how hot the windows/wall get? Very nice looking set-up, by the way.

thanks much