Class A Chimney pipe inside room?

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mchristo

Member
Hearth Supporter
Jun 16, 2009
36
Tuftonboro, NH
I'm installing a wood burning sauna stove in a small out building.

I'd like to run double walled Class A Chimney pipe (5" Simpson Duratech) right from the top of the stove with a stove adapter.

The stove is from Finland and is designed for 12 centimeter stove pipe. (12cm = 4.72 inches). I will have the 12cm stove top adapter(supplied with the stove) customized my a metal fabricator to fit inside the 5" chimney pipe.

my question is; if I fabricate the adapter to fit perfectly inside the 5" Class A Chimney pipe, can I simply run that pipe all the way up through the roof and attach my chimney cap? (obviously I would use all the appropriate radiation guard/flashing etc where it penetrates the roof)

I like the stainless steel pipe for inside the room because it will be a humid environment and will not rust.
Also, I think it must be better insulated to allow for 2" clearance vs the 6" of double wall stove pipe, or 18" clearance of single wall stove pipe.

Ive researched and it seems like you can use this pipe inside the building, but its supposed to be enclosed in a 1 hour enclosure. The problem with that is I can't install a 1 hour enclosure directly over the stove.

I don't understand why the Class A Chimney pipe needs to be enclosed while a single wall stove pipe can be left exposed?
 
Yes you can do it. You will need to support the chimney with a support kit. Basically thats a couple of brackets that screw into chimney and into supporting roof trusses or you build supports on to trusses. Just look for support kits and pick the one with brackets and build to fit. If I remember those brackets are well rated but check they will hold your load. I used them and I always over do it so I used 2 kits.

Class A has to be enclosed in living areas for 2 reasons first incase of chimney fire second it needs 2" clearance and someone will put something next to it someday. The single wall goes straight up from stove and is not legal to pass through ceiling so does not go into living areas and restriction not necessary.
 
Agree with snowtime, our inspector basically put it, if you could bump up against the pipe, then it needs to be enclosed. He related this is mainly for closet and bedroom passthru's above the room with the stove. see signature link down below for class a inside a home (we just had it painted, updated pics on page 2)
 
Thanks for the replies.

I've spoken the the rep for the stove who explained to me that the weight of the pipe is what seals the adapter pipe to the stove. the stove comes with a 12cm to 6" adapter for 6" stove/chimney pipe, but I'd like to use the 5" class A Chimney pipe as explained above. I think this will create better draft in the chimney and just look better aesthetically. He said what I wanted to do was fine, but to make sure the 12cm to 5" adapter was made of strong steel. (I assume the 24 gauge stuff they sell will not cut it.) so I am having that custom made. I'm only using about 12 feet of chimney pipe from the top of the stove so I know the pipe can support itself for that long. I am also sure that the stove and adapter will be able to support that weight.

That being the case do I still need to use support brackets? or can I just use the proper insulation shield / radiation shields where it penetrates the ceiling and roof?

I don't want to use too much support so that it doesn't create a positive seal around the stove opening.

Here is a link to the instructions for my stove. I have the 20 Pro model with the Harvia Protective Sheath that they refer to, and it is in a log cabin.
(broken link removed to http://harvia.com/files/prod_pdf_tech/1376/Pk_ENDE.pdf)
 
You still need the support brackets. Just put as much weight on the stove as you need then tighten down the roof brackets.
 
snowtime said:
Class A has to be enclosed in living areas for 2 reasons first incase of chimney fire second it needs 2" clearance and someone will put something next to it someday. The single wall goes straight up from stove and is not legal to pass through ceiling so does not go into living areas and restriction not necessary.

I just want to make sure you understand that in this installation I am NOT going to enclose the class A chimney pipe where it is inside the same room as the stove and that is ok? The chimney will be exposed all the way up, but maintain proper clearances and support brackets where it passes through the roof.


Also, it is ok not to have any "venting" pipe come out of the stove?

thanks for putting up with the Newbie questions. better safe than sorry thought.
 
why the heck would you need to enclose class A if your not required to enclose single wall in a room?
 
greythorn3 said:
why the heck would you need to enclose class A if your not required to enclose single wall in a room?

I had the same question....and I can't understand it either. its clearly superior pipe to single or even double wall stove pipe. the only think I can think of is they are talking about when it penetrates through a second story living space, they don't want it exposed so that people will lean things up against it or bump into it etc. It wouldnt make sense to enclose it if you use it as a stove pipe.

Not sure if there is any other reason not to use the Class A as "stove pipe"?
 
It is preferable not to cover it in your sauna or in your house. It emits heat and keeps the flue temps higher (well it does inside the house exposed or not).
Plus it looks tres sexy.

Hell I would use single wall inside a sauna. More heat engine room, more heat.
 
d.n.f. said:
It is preferable not to cover it in your sauna or in your house. It emits heat and keeps the flue temps higher (well it does inside the house exposed or not).
Plus it looks tres sexy.

Hell I would use single wall inside a sauna. More heat engine room, more heat.

I'd think the class A would keep the flue temp higher since it keeps the heat inside the pipe? I think the stainless looks better than the black pipe. Is that what you are saying as well?

Yes Single wall would emit more heat into the suana, but I don't think that will be a problem for me. The stove is plenty large enough for the room. I think I'm going to have to ventilate the room to keep it from getting too hot. besides the REAL heat comes when you throw water on the rocks and your freinds are running for the door! :)
 
Class A is the way to go. If you read my post again you will see that single wall does not have to be enclosed because its is illegal to pass through ceiling. To be blunt NO pipe has to be enclosed from stove to ceiling the restrictions are on living spaces above the stove room. Of course you need to maintain clearances for the pipe you have selected in the stove room and proper fittings to pass through ceiling.
 
snowtime said:
Class A is the way to go. If you read my post again you will see that single wall does not have to be enclosed because its is illegal to pass through ceiling. To be blunt NO pipe has to be enclosed from stove to ceiling the restrictions are on living spaces above the stove room. Of course you need to maintain clearances for the pipe you have selected in the stove room and proper fittings to pass through ceiling.

thanks Snowtime! One other objection I've come across for using Class A right from the stove is that it does not 'vent' the heat from the stove, and could therefore overheat the stove. Should I be at all concerned about that?
 
You will not over heat the stove with Class A. It will mean less heat in the room but you should have a stove rated to do the job without having to resort to single wall for help. The other positive is your chimney will draft better and there will be less creosote as the chimney will keep a higher inside temp.
 
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Thanks again Snowtime. I see you are in BC. I lived in Vancouver for two years. Beautiful part of the world. And the best skiing in NA! Enjoy the Games!
 
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