Bathtub venting

Discussion in 'Shower & Bathtub Forum & Blog' started by dtms, Apr 9, 2014.

  1. dtms

    dtms New Member

    Messages:
    5
    Location:
    ME
    I need to run my trap arm from the p trap to the main drain under the tub so it runs parrallel to the tub (looking at tub, tub drain is on left and main line i'm draining into is on the right running perpendicular to the tub). Can i attach a vent in the trap arm with a 45 wye say 3' from the p trap so the wye goes up but at a bit of an angle so i can go towards the back wall of the tub and up the back wall of the tub to tie into a vent in the ceiling? I'm a little confused how else to do it.
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,124
    Location:
    Bothell, Washington
    The vent for the tub trap arm can be within 42"
    The vent can run at a 45, which is still considered vertical.
  3. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,139
    Location:
    New England
    It's dangerous to your financial health to do your own plumbing in MA, but a vent must go up above the floor plane of the highest fixture or 42" whichever is higher before it can turn horizontal. On a two inch drain, that connection must be made within 5' of the trap, it gets smaller or bigger depending on the drain line size.
  4. dtms

    dtms New Member

    Messages:
    5
    Location:
    ME
    Thanks for the reply. So does the wye have to go straight up or can it go more towards the back wall of the tub as long as that piece between the wye and the 90 going up into the wall is pitched. Is this a common way of venting tubs or is there a more common way that i'm missing?
  5. dtms

    dtms New Member

    Messages:
    5
    Location:
    ME
    Thanks for the advice Jim. I live in MA but this is a vacation home in ME i'm working on. So you are saying i would need to come straight up from the arm thru the floor and then i can go horizontal over to the wall. Is there a better option that i'm missing?
  6. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,249
    Location:
    Land of Cheese
    The wye, (and the vent) must be turned up at least 45 degrees. If you run the drain under or close to the wall, this should not be a problem.
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,139
    Location:
    New England
    However it goes up, it must go up at least the 42" before it can turn horizontal...45 or greater is considered vertical for these purposes.
  8. dtms

    dtms New Member

    Messages:
    5
    Location:
    ME
    I think I understand. So run the p trap and the arm over towards the back bathtub wall so when i come off the arm with the wye i can basically go straight up into the wall. Is that the idea?
  9. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,139
    Location:
    New England
    Anything 45-degrees or higher is considered vertical for this purpose, and that link must be within the specified distance based on the size of the pipe.
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