Washer and sink drain questions

Discussion in 'Plumbing Code Questions' started by techinstructor, Apr 3, 2011.

  1. techinstructor

    techinstructor New Member

    Messages:
    81
    Location:
    North Carolina
    I have two code questions.

    The first one concerns the drain line from a clothes washer.

    The washer drain will connect to a horizontal drain that will also carry waste from the lavatory and tub. This horizontal drain will then connect via a combo wye to the main 3" horizontal drain that goes to the vertical drain that goes out to the septic tank. I'm unsure of the terminology, but I would think that the horizontal drain that the washer, lav, and tub feed into would be considered a horizontal branch drain. If this is true, then do I need to use 3" pipe for that horizontal drain per N.C. code 406.3

    The inspector looked at my plan and actually told me to use 2" for that drain, but it seems that his advise is not in sync with the code. The problem is the inspectors rotate jobs, and I'm not assured that the inspector who told me this will be the one who actually does the inspecting.

    Second question.

    I have a double sink in my kitchen. Is there anything in the code that says which type of continuous waste outlet I can use? I cannot find any reference to it, but again, I may not know the correct terminology.

    The inspector drew one that had an end outlet like this one:
    [​IMG]

    But I prefer to use the one with the center outlet like this one:
    [​IMG]

    It's a spacing issue, but I could make either work. Both have a baffle tee, so I can't see why it would matter. Please advise.

    Thanks
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,283
    Location:
    Bothell, Washington
    You can always plumb better, but not worse.
    Go ahead with the 3" horizontal on the washer waste line.

    Most plumbers prefer the end outlet for the kitchen sink.
    I'm not a big fan of the center connector.
  3. techinstructor

    techinstructor New Member

    Messages:
    81
    Location:
    North Carolina
    Is it more susceptible to clogging? Just wondering why.
  4. Terry

    Terry Administrator Staff Member

    Messages:
    15,283
    Location:
    Bothell, Washington
    It's hard to get the proper grade in the middle.
  5. techinstructor

    techinstructor New Member

    Messages:
    81
    Location:
    North Carolina
    Do you mean that these have to be installed so that the pipes slope 1/4" per foot from the drain to the tee?
  6. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada

    Always... Everything needs to slope downstream...
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