So the house/building I was on today had some metal vent pipes. Thsi hosue was OLD!! 1910 i think. I’ve never seen this style of vent pipe before, is this approved for this?? The pipe was roughly 1.5". I tried to see any connections to the sewer lines but I couldn’t find them, must be in the wall.
Also Does anyone have a good picture/diagram of clearances requirements of a sewer
vent pipe to the house?
I suspect that is simply wrapped around the original vent (likely cast iron).
I don’t think there’s any requirement other than to windows, etc. They are an uncommon material but as Dominic said, they may just be wrapped cast iron… or maybe an extension for an upper floor addition? In the grand scheme I’m guessing there are “bigger fish to fry” on that place 
Oh so many fish!! Its like a good old all you can eat fish fry.
