I think it has to be a double san tee not that double wye fitting because the deep V area of wye fitting cuts off the vent air and can cause traps to siphon upstream. A double san tee fitting the vent is level to the top of the two incoming pipes there is no V shape so air is always in the top of the pipes for venting.
But on the 2" inlet, are your shower and drain already vented? If so, that fitting would be functional for bringing the drain in, not sure what the UPC or IPC has to say about it, though. If not, that fitting would not be suitable for venting the 2" line.
There is a long thread on here about double fixture fittings vs double santee vs double combo wye fittings and the differences of where they can be used.
https://terrylove.com/forums/index.php?threads/double-fixture-tee-or-double-sanitary-tee.22539/
In the thread terry says at least a double fixture for back to back toilets, but that will still siphon. ..and they only make double fixtures up to 3"
A double wye is the only way to go with these new toilets
Can you provide a reference to the IPC or UPC section that says that?The codes say the double wye is not the correct fitting due to it creates a 3/4 S trap.
It has to do with the weir of the trap and the vent level of the fitting thats why a santee is used not a wye in vertical orientation.Can you provide a reference to the IPC or UPC section that says that?
Thanks, Wayne
Can you provide a reference to the IPC or UPC section that says that?
Thanks, Wayne
Good point however toilets dont come into play asa the trap (w/c) is already above the vent takeoff. its exempt from needing a santeeI think it has to be a double san tee not that double wye fitting because the deep V area of wye fitting cuts off the vent air and can cause traps to siphon upstream. A double san tee fitting the vent is level to the top of the two incoming pipes there is no V shape so air is always in the top of the pipes for venting.
Not according to HJ who is a master plumber and said on other threads the codes do not allow a double wye only a double fixture fitting.Good point however toilets dont come into play asa the trap (w/c) is already above the vent takeoff. its exempt from needing a santee
That is an excellent point. If the side inlet has the radius of a san-tee, then you can use it for a drain horizontal to vertical. Otherwise, no drain attachment.And on another note, the side inlet fitting he shows is not approved for waste connection to the side inlet because there is no radius on the side inlet connection. That side inlet can only be used for a vet connection not waste.
Start reading at post #21 of this thread where HJ says his inspectors would not allow that type of fitting per code on back to back toilets.As to using a wye for a toilet fixture drain to stack connection, it is allowed for the reason I explained previously.
IPC 909.2: The total fall in a fixture drain due to pipe slope shall not exceed the diameter of the fixture drain, nor shall the vent connection to a fixture drain, except for water closets, be below the weir of the trap.
UPC 1002.4: The vent pipe opening from soil or waste pipe, except for water closets and similar fixtures, shall not be below the weir of the trap.
Cheers, Wayne