Single wall or double wall stainless chimney pipe

[claystroup]

Wondering if using single wall 8" stainless chimney pipe is sufficient going through the roof of a sugar shack. If the 8" chimney is put in the center of a 24" wide distance between rafters, would this provide enough clearence to the 2 x 6 roof rafters. If not, would wrapping the pipe with 2000 degree ceramic blanket from the roof down about 24" provide the needed heat protection from the 2 x 6 rafters. In this situation there would need no other combustible materials nearby.

[mol1jb]

I believe fire code is 16” clearance on single wall stove pipe. I assume this would be the same. So less would need some sort of protection

[Road's End]

You can never be too safe, but you'll want something to shield the rafters in my opinion whether the code says it's required or not. Evaporator stack temps can get pretty high!

[maple flats]

My stack is single wall SS pipe. At the space where my stack was going thru the roof I spaced that set of trusses 32" apart, the rest are 24" except the one adjacent to the one spaced extra, so those 2 combined equal 48" on center. To get the safety needed I then wrapped the stack with 1.5" thick 2300 F ceramic blanket and made a ss outer cover to both dress it up and protect the insulation.
When I was installing my woodstove in my previous house the code at that time required 36" clearance to the stove and any single wall pipe. That could be reduced by half with a layer of metal or other non combustible spaced out 1" on a non combustible spacer. Each additional layer likewise spaced cut it in half again. (Codes may have changed, that was in 1975, national fire code). Thus 1 layer needs 18", 2 layers need 9" and 3 layers gives you a safe clearance of 4.5" (from the last layer, not the pipe.)
Protect that wood, most fire insurance will not cover a loss from an improperly installed stack, some won't even with a properly installed stack.
Besides the sugar house think of all of the equipment that might someday be in there, loads of dollars worth for sure.

[Austin351]

Or get a section of Class A stovepipe where you are going through the roof. I often see it on Craigslist / FB Marketplace at a reasonable price (I purchased 24' x 8" for $100, used of course). The clearance for Class A is only 2" where as single wall is 18" and double wall is 6"