1-1/2" vs 2" for bar sink?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by MajMetro, Aug 4, 2012.

  1. MajMetro

    MajMetro New Member

    Messages:
    22
    Location:
    Portland, Oregon
    I'm helping a friend with his DWV layout.

    rods_dwv1.jpg

    Looking for a Pro's view on whether we could use 1-1/2" vs 2" on the run from the 10"x12" (no disposal) bar (prep) sink to the 2" kitchen sink line.

    Note, we have to transition five (5) 2x10 floor joists to access the 2" run. Technically 1-1/2" will work, just wondering what everyone's experience has shown.

    Thanks,

    Mario
  2. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,398
    Location:
    Yakima WA
    Where are the traps? Every sink needs a p trap and vent. I see the AAV for the bar sink, and that may be OK, but the kitchen sink with the DW and disposal must have a trap and there must be a vent.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,286
    Location:
    Cave Creek, Arizona
    HE is NOT revising the sink and disposer so that is immaterial to the discussion. 1 1 /2" is "technically" okay, but functionally, 2" will perform better over the long run. And you will appreciate the difference when it plugs up and you have to snake it. This will occur much sooner with 1 1/2" than 2", also.
  4. MajMetro

    MajMetro New Member

    Messages:
    22
    Location:
    Portland, Oregon
    Thanks HJ. I had read this before somewhere in the forum. Just thought I'd throw it out there and confirm it.

    Mario
  5. Terry

    Terry Administrator Staff Member

    Messages:
    15,438
    Location:
    Bothell, Washington
    Like hj mentions. for a bar sink, 1.5" passes code, but it's also half the volume of a 2.0 pipe. Cost is almost the same for both pipes.
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