Toilet wet vent under IPC

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by brewdesign, Dec 28, 2012.

  1. brewdesign

    brewdesign New Member

    Messages:
    12
    Location:
    Berkley, MI
    I've looked through quite a few threads looking for specifics on using a wet vent on a toilet arm under IPC. From what I can tell, IPC lists no specific toilet vent requirement. In the attached drawing, a 2nd floor bathroom group is draining into a new 3" stack. The stack runs down to the main floor then under the kitchen picking up a kitchen sink then wyes into the building drain.

    The 3" toilet arm has a 2" wet vent that connects through a combo then runs 45* before running vertical through the bathroom wall. Inside the wall a san tee accepts sink waste then above that (above flood rim) two tees brach in the sink and tub dry vents. The vent continues through roof. The tub waste drains via a 2x3 wye into the 3" stack under the toilet arm (due to space constraints in the joist bay).

    So the question is whther or not this is an acceptable arrangement under the IPC. I think this fails under UPC since the toilet vent would seem to be required on the arm before the sink drains in.

    Thanks in advance. bath2.jpg
    Last edited: Dec 28, 2012
  2. Hammerlane

    Hammerlane Member

    Messages:
    263
    Location:
    Ohio
    The part of the 2" that leaves the water closet 3" line to the right cannot be on the horizontal
  3. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,274
    Location:
    Land of Cheese

    Can you explain that further? It is a wet vent.
  4. brewdesign

    brewdesign New Member

    Messages:
    12
    Location:
    Berkley, MI
    It is drawn poorly. The branch rises at 45 degrees before going vertical. Thanks for the responses.
  5. Hammerlane

    Hammerlane Member

    Messages:
    263
    Location:
    Ohio
    Im having trouble uploading photos. But look at his diagram and start right next to the words "water closet". Follow that 3" and at the point where the 2"(from the lavatory) ties into the 3", the section of 2" appears to be on the horizontal. Are you saying that because that is part of a wet-vent, the horizontal is OK?

    Thanks
  6. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,274
    Location:
    Land of Cheese
    A wet vent can be horizontal, and the IPC specifically approves went venting a bath group through the lavatory. The distance between the trap and it's vent must still be within what is allowed for the pipe diameter.
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,242
    Location:
    Cave Creek, Arizona
    My previous answer was either lost or deleted. SInce the toilet drain is washed by the lavatory drain, the horizontal section is proper. You might not even need the "loop" for the lavatory and vent, depending on its distance from the vent, or if you can relocate the vent closer to the sink.
  8. brewdesign

    brewdesign New Member

    Messages:
    12
    Location:
    Berkley, MI
    Thank you again HJ. I didn't realize that the section in question could be horizontal but that makes sense. I ran that 2" vent section up at a 45 because I originally intended for it to be a dry vent. I later realized it could be converted to a wet vent to simplify the lav routing that would have been under the cramped joist bay. I finished the rough in per the drawing, albeit with a vent loop that was probably not necessary, but I already boared the holes and just went with it.
  9. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,242
    Location:
    Cave Creek, Arizona
    In fact, if the situation allowed it, I would have offset the vent so it was behind the lavatory with a 2x1 1/2" tee for the sink drain.
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