Double wall stove pipe, Clearance

[nshif]

Im installing a Quad 4300 ST. Clearance for double wall on the stove pipe is 12". Is this from combustables or from my ceramic rock veneir? I have 1/2" cement board behind the rock so do I measure from the back of the cement board or the face of the rock?

 

[elkimmeg]

there is some debate here hearthtools and I discussed this matter I say it is to the cumbustiables underneath but hearth tools also made a good case asaying it is from the surface attached to the non combustiables It would be best you ask this question to the inspector that will be doing the inspection

 

[Shane]

We always measured to the combustible. But like Elk said it's the inspectors call there.

 

[Metal]

It is measured to the combustibles, it doesn't matter what you put between them. You could install heat shields from the space shuttle between the pipe and combustible surface and the clearances wouldn't change.

 

[Highbeam]

I thought it should be clearance to combustibles too but then consider that the air gap created by this clearance is vital to keeping the combustible cool with its air currents and the air gaps R-value. You are proposing to place stones between the paper and stove but what if you filled that space with a chunk of steel. Clearance from the back of stove to paper is the same but the decorative chunk of steel will soon become the same temp as the stove, since it is touching both stove and wall, will effectively eliminate the clearance. I have concluded that the air gap is what is required by the clearance, it matters what's in between.

Plus, that would be conservative. I built in several extra inches of rear clearance behind my stove to allow for a veneer of stone someday maybe.

 

[nshif]

No the rock is placed on a 1/2" layer of cement board attached to the wall studs. Im not talking about stove temps which are much higher then stack temps and the stove is ok to the combustables not the rock.

 

[jtp10181]

Most clearance listed for pipe and stoves, etc are air space clearances, although I think I have read some stated as a clearance to "combustibles". With a 12" clearance I don't think cutting it down a little with a non-combustible would be much of a problem but you definitely don't want to make the entire space non-combustible materials. You always want to have proper air flow around the vent for cooling. BTW what double wall are you using? Simpson DVL has a 6" clearance to combustibles so that might be a little better for you.

 

[nshif]

jtp
Im useing simpson but Quad states 12" If I can get by with 6 this is not really an issue. I can get by with 12 it just puts the stove a little further into the room. seems funny I can have 2" CTC on tne stove corners ( corner install ) and need 12" for the stove pipe.

 

[jtp10181]

I reviewed the manual and was looking at page 7. I don't see a 12" clearance listed for the double wall section at all, make sure you are looking at the correct table. Anyway... I think they are showing the clearance to the pipe collar relative to the clearance to the back of the stove. Meaning that if you keep all your stove clearances that is where your collar should end up. Some people find it easier to measure from the collar than the back or corners of the stove itself. Once you come off the stove you could offset closer to the wall as long as you maintain the pipes listed clearances.

Am I missing something? Sounds logical to me.

http://content.hearthnhome.com/downloads/installManuals/man_4300.pdf

 

[Metal]

Always follow the stove manufacturer's installation instructions first, they trump the vent manufacturer's installation instructions every time.

 

[stoveguy13]

Is it an act or an acc there are some cleareance diffrences on the two