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You should also consider putting a rain cap on the top of the pipe (example: https://www.amazon.com/gp/product/B0017LXW7E/ref=s9_dcacsd_dcoop_bw_c_x_1_w) but sized for the appropriate stock you use (I didnt check the sizing on that link... it was for illustration purposes only).
I would say it depends on clearances (like a wood stove chimney). You will definitely need to fab up a pass through box (or find something for a pellet stove and adapt it) so you are far enough away from combustible materials. YMMV
You can use regular black iron pipe for this (its an NPT fitting). I forget if its 1" or 1.25" off the top of my head, but you just need a BI coupler and whatever length you want to extend the stack by.