Hi, and thanks so much for the continued interest! I know everyone is at least as busy as I am, probably more so. I'll try to be concise. the town requires a state mechanical inspection of the install. the fire dept and the state inspector require a licensed contractor/plumber/hvac person do the install.
the state inspector wants the manufacture's recommendation for installation.
the manufacturer recommendation is installation to meet or exceed local codes, and recommends Class A pipe.
I think that the state does not know what it's codes are for a coffee roaster. I think most roasters just put them in.
after a day or two of phone calls back and forth, it was determined by the state inspector and the contractor, that simpson dura vent made a class A triple wall pipe, available locally, that would meet the requirements/codes. However, after I purchased the pipe, I realized there was no fitting made to penetrate the roof with this pipe, called simpson, who manufactures the pipe and they said the triple wall pipe is not safe for that use, and I needed a class a double wall pipe.
the closest selkirk dealer told me it would be 8-10 WEEKS until I could get their pipe. and I think the pipe they are referring to is positive pressure commercial pipe. and I think it is overkill. but I don't know. he also was supposed to send me price quotes, and has not yet.
I think at this point the question is what double wall pipe qualifies as "Class A" and do I need positive pressure pipe?
I have another contractor coming next week, I wish I'd waited for him in the first place. he is more knowledgeable, he is less intimidated by the state inspector, more likely to say "this is what we need", and have the inspector go along. His first suggestion was to just put it in and deal with the inspectors afterwards. but I don't want to pay for installation and get in trouble next fire inspection, or have it be the wrong pipe for the roaster to work well.
I've been roasting for 4 years in a metal shed with single wall stove pipe. I didn't know it would be this involved.
but the coffee I'm roasting at night is good, I think the best ever.