So this is what came down to. I was ordered to do use a transition coupling on the stub out and go to copper so technically the flushometer is being connected to copper, by their(my boss) standards. I felt this was wrong and refused to do this as I felt this is bad workmanship practice. I suggested to build a false wall and run copper to the ceiling but they weren't going for this. I haven't been able to find any literature that says in black and white "you cannot use cpvc to attach a flushometer". My bosses say since I can't find it doesn't mean you can't do this. The kicker is that the engineer has clearly on the prints to use cpvc stub outs. Now my bosses are asking me "so you mean to tell me that you know more than an engineer?" In this case I do. I told my bosses that I'll write a memo stating that I disagree with this idea and my solution to it but am being told to do this the wrong way. I will have their names stating they agree with that statement. When I brought this up; all of the sudden people got much nicer and the sense of urgencies gave way to "let's spend some more time on this and research this throughly." Hope my cilvian dream doesn't get speeded up by this incident but I can sleep good knowing I did the right thing.