Trying to determine if an installation is original or after the fact.
No idea this might give you some ideas … Roy
They do a great job of defining what it is, but not when it was developed.
Try the Hart and Cooley site.
I have no time to search today but it may be there.
I’d like to help you too but I’m eating a late lunch working on my report.
Finished the report, and still haven’t found it. Wrote two long ones this morning now I’m headed out to do a winterization. I ended up just reporting the clearance problems and didn’t make any statement about whether or not it was an after the fact installation or not.
Thanks for the update. How was lunch?
Transite piping (asbestos-based cement piping) was a listed B-vent, and used through the late 70’s. Modern B-vents are double-walled steel, and originated (I believe) in the early to mid 70’s.
Who cares if it was done originally or not. If it has clearance problems its wrong.