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Another plumbing question…

mmoogie | Posted in Construction Techniques on May 16, 2008 08:22am

How do you plumbers feel about wyes feeding into a horizontal drain line with the wye laying on it’s side rather than at 45 degrees or more? Is it legal? Is it bad practice? Is it done all the time?

Steve

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  1. MNScott | May 16, 2008 08:28pm | #1

    Mmoogie,

    check with your local building codes, but here in MN you are only allowed to use a wye in a vertical stack. I had to rip out an installation when the inspector alerted me to this requirement.

    Scott

    1. User avater
      mmoogie | May 17, 2008 05:40am | #6

      Scott, I find that hard to believe. I think your inspector must be confusing the rules for a sanitary T.I just passed the licensing test for GC in MN. and they go by IRC, which allows the use of wye's horizontally. It would be virtually impossible to plumb much of anything without being able to tap into a horizontal branch line with a wye, at least with wye rolled up 90 degrees from the horizontal. My only question is whether it's allow with the wye on its side or not. IRC seems to say yes, according to the attached table.Steve

      1. User avater
        FatRoman | May 17, 2008 06:14am | #9

        Hi Steve,I looked at my code book earlier and it appears that you should be fine. It matches what you've got in your table here. As a drain, it can be horizontal under UPC or IRC. As a vent it needs to be 45 deg.If you have room, you might be better with a combo than a wye, but I don't believe that's a necessity.And for the standard disclaimer, I'm not a plumber. Are you moving back to MN?Best,
        Steve'Man who say it cannot be done should not interrupt man doing it' ~ Chinese proverb

        1. User avater
          mmoogie | May 17, 2008 02:33pm | #10

          Hi Steve,In the long run, maybe. My wife has been working out there for almost a year now. She went under the assumption I would be right behind her. She wasn't out the door but a moment when I got a call to do a whole house remodel that I've been working on landing for about eight years now. So It's looking like it's going to be awhile. But that is still the working plan. But you know what they say about plans...Steve

  2. MikeHennessy | May 16, 2008 09:38pm | #2

    Illegal here.

    Mike Hennessy
    Pittsburgh, PA

  3. MSA1 | May 16, 2008 11:32pm | #3

    Not sure about your specific situation but I do know that its better to have wye than a tee.

    Check with your BI.

    1. User avater
      mmoogie | May 17, 2008 05:41am | #7

      As far as I know, a T on its side is always illegal, as well as bad practice.Steve

      1. MSA1 | May 17, 2008 03:45pm | #11

        You're right. You have to allow direction for the water. A "Y" is more likely to provide that (though not guarenteed to).

  4. davidmeiland | May 17, 2008 04:33am | #4

    There are millions of wye fittings out there laying on their side. I'm not sure how you would plumb the drains in a single story house over a crawl (or SOG for that matter) without them... all those drains coming from the various rooms and needing to be tied together into one main drain leaving the house.

    Now, when a wye or tee is used on its side as a VENT TAKEOFF it cannot be level... you have to rotate the side up at 45 degrees. Maybe that's the part that has you confused.

    You can use a wye vertically. How else are you going to tie together two vertical lines? There's at least one gotcha related to using a wye or combo vertically if it's a trap arm inlet into a stack. Gotta use a tee there.

     

     

     

     

     

    Or am I confused?

    1. User avater
      mmoogie | May 17, 2008 05:32am | #5

      I ask because I just ripped out the drain setup that my plumber installed for a small bathroom I put together last fall. It's over a tight crawlspace, and he had the lav and the shower coming into the main horizontal via wye's on their side. I know I've read in various places that they should be rolled up at least 45 degrees. The most recent place being in Rex Cauldwell's (taunton press) book. In my re-working of the drain setup, I too found it impossible to get them up above horizontal very much, The shower now comes in maybe 10 degrees above horizontal, and the lav no more than a few degrees.I ran into another local plumber at lunch today and asked him if it was kosher. He said sure, as far as he knew. And this particular bathroom passed inspection (before I changed it) without a second glance. I could find nothing in the IRC that forbids it. In fact the attached table seems to say it's OK. I've no doubt it'll function fine, I was just wondering how pervasive the practice is.Steve

      Edited 5/16/2008 10:43 pm by mmoogie

      1. davidmeiland | May 17, 2008 05:53am | #8

        Maybe Plumbill will come along and hook us up...

        1. plumbbill | May 17, 2008 06:26pm | #12

          I don't know of any code that prohibits a "wye" branch fitting on a horizontal plane to tie two drain or vent lines together.

          Where codes vary is when the vent comes off the trap arm, almost all codes require the vent take off to be above the centerline of the horizontal waste line.

           

          “The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing.” —Albert Einstein

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