I feel UPC's venting rules on W.C.s are an overkill. Are they not self siphoning traps?
I agree wholeheartedly. Sadly, what the inspector sees is what has to pass code. If only there were some way to cover the pipes with invisible paint.
I think a vent anywhere on the branch to the toilet would be sufficient to prevent other fixtures from causing the toilet to self siphon. You could even put a stipulation on it that it has to be in walls of the same room with the toilet.
In reality though, in my 5.5 years plumbing, i haven't encountered any buildings (mostly custom homes) where it was impossible to get the vent in the way our code requires it. There have been a lot of very tight situations, but none impossible.
I also wanted to note that scrolling back through the thread has caused me to notice how staggeringly accurate my 45* offset on that iso looks. Usually they are very difficult to portray, but I think I nailed that one. (with MSpaint no less )