Venting Up and Down in Attic?

Discussion in 'IPC Plumbing Code Questions' started by Scott Yackley, Aug 22, 2020.

  1. Scott Yackley

    Scott Yackley New Member

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    Jul 13, 2020
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    48383
    Is venting up then down in the attic to get to main vent stack acceptable? Vent line would be 2" and main vent stack can support these additional fixtures.
     

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  2. Reach4

    Reach4 Well-Known Member

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    Sep 25, 2013
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    IL
    From what I had read, that may be OK under IPC but not UPC. MS uses IPC.
     
    Last edited: Aug 23, 2020
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  4. Scott Yackley

    Scott Yackley New Member

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    Thanks! It doesn’t create a trap, so figured it was ok but wanted to check. I couldn’t find this specifically mentioned anywhere in the code.
     
  5. Reach4

    Reach4 Well-Known Member

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  6. wwhitney

    wwhitney Well-Known Member

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    Location:
    Berkeley, CA
    I looked it up:

    IPC
    https://up.codes/viewer/colorado/ipc-2018/chapter/9/vents#905.2
    "Vent and branch vent pipes shall be so graded and connected as to drain back to the drainage pipe by gravity."

    UPC
    https://up.codes/viewer/california/ca-plumbing-code-2019/chapter/9/vents#905.1
    "Vent and branch vent pipes shall be free from drops or sags, and each such vent shall be level or shall be so graded and connected as to drip back by gravity to the drainage pipe it serves"

    UPC makes it clear the vent has to drain back to the drainage pipe served, meaning the OP's configuration wouldn't comply. Since IPC just says "the drainage pipe" I say sloped back to any drainage pipe is OK, meaning the OP's configuration complies.

    Cheers, Wayne
     
    TheOverThinker and Reach4 like this.
  7. Scott Yackley

    Scott Yackley New Member

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    Thanks a lot for your feedback, this makes more sense now.
     
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