OK, thanks for people's help on my last question, now I've confused myself again. I came across this picture, similar to the last question, but I don't think it's a cleanout. It looks like a vent to ...
I recently saw a plumbing setup where a 2" pipe was run from a bend in the 4" toilet return. The 2" pipe bent upwards to meet the floor next to the toilet, where it was capped off with a removable ...
Most of the info I have on code implies this would be OK, but one item I have says that a 1 1/2 vent can only serve 8 "non-WC" fixture units.