Insulation batts over elbows & pipe sealing rigid liner

[mossycup]

I have run into a bit of differing opinions on two subjects regarding my rigid single wall liner:

Somewhere in the NFPA 211 it is stated insulation is NOT permitted over pipe connectors...is the mineral wool blanket I am going to wrap the rigid single wall with considered insulation? I have a 30 degree elbow in the smoke chamber and one above the damper block off area...I was going to wrap all the way down to the top of the lower elbow. Is this not advised?

Secondly, BEFORE I screw all my vertical pipe and elbows together is there any reason that I should think of sealing/cementing each joint? I have been told be one stove shop it is necessary, and another claims the complete opposite.

Thank you

 

[SteveKG]

I don't want to lead anyone down an unsafe path or anything, but nevertheless I have never sealed or cemented pipe joints nor do I know anyone who has, and there are lots of wood stove users here in my area. For what it's worth....

 

[webby3650]

No reason to cement the joints in the pipe. Any reason you are not using a flex liner? The ceramic wool insulation is made to wrap a liner, the NFPA code you are referring to likely means fiberglass insulation. Are you insulating the entire liner or only part of it? I would recommend insulating all of it, if your are going to the trouble.

 

[mossycup]

Those are my thoughts on the sealant issue. I just noticed another post relating to this and it sounds like as long as I have 3-4 screws per joint, we're on track.

As far as the insulation, I am using rigid pipe in a terra cotta lined masonry chase. I only have about 16' of chase to work with and two 30s over a rear vent...so after some research, I felt the smoother pipe would benefit to some degree since I suffer from short chimney. I'll probably need all the help I can get.

 

[kgrant]

Rivet the pipe instead of screwing it, especially the joints you won't have access to again. Use stainless steel rivets.

I tried using furnace cement to seal pipe joints, but it all cracked out in a short time from expansion/contraction. Maybe I was using the wrong stuff?