Garage Bathroom Rough-In Piping

Discussion in 'UPC Plumbing Code Questions' started by EdNC, Mar 30, 2020.

  1. EdNC

    EdNC New Member

    Joined:
    Mar 8, 2020
    Location:
    North Carolina
    I am in need of some guidance regarding Rough-In piping in my pole barn before I pour the concrete slab. The bathroom is 6'x9' as shown in the diagram. Blue are 2" pipes and Green are 3" pipes. Will this setup pass inspection. Do I need a vent for the shower? Do I also need a Clean-out? Thank you. Pole Barn Plumbing Layout 4.jpg
     
  2. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Something like this maybe. Lav wet vents the shower and toilet. So toilet after lav and shower The drain from the lav over to join the shower drain could be in the wall instead of the floor I think. If the general concept works, then we could discuss the fittings to implement and max distances.

    If the general concept works, then improvements are obvious, such as toilet drain angling rather than being at right angles to walls.
    Red and purple are 2 inch.

    Edit: revised attached sketch.
     

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    Last edited: Mar 30, 2020
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  4. EdNC

    EdNC New Member

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    North Carolina
    Basically I am required to vent the outside utility sink separately based on your drawing. It cannot be wet vented with the inside sink?
     
  5. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    I think so . For sure that way with UPC, but NC is IPC.

    See https://wabo.memberclicks.net/assets/pdfs/Plumbing_Venting_Brochure_2018.pdf and note this:
    Section 202 of Chapter 2 is the key to the maximum number and type of fixtures that can
    be accommodated by a horizontal wet vent. The definition of Bathroom Group is a group
    of fixtures consisting of a water closet, lavatory, bathtub or shower, including or excluding
    a bidet, an emergency floor drain or both. ​

    There are 5 other occurrences of bathroom group in that pdf.

    Note that your laundry sink is not one of the things listed in a bathroom group.

    However under IPC, it may not be necessary to make the toilet the last thing in line for the bathroom group. Read that pdf.
     
  6. Terry

    Terry Administrator Staff Member

    Joined:
    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    Venting at the sink and lav takes place on the high side of the trap arm.
    Expecting it to magically be vented lower than that isn't science. Without the vent on top, everything siphons.

    The shower can do a horizontal wet vent as the pipe eventually rises upward, not down. It's also run with 2" which allows what would be an 1.5" drain on the lav to be twice the size in volume, allowing air over the draining water for venting.
    The toilet can be wet vented by the lav/shower, but not by the laundry sink. The laundry sink not being a bathroom fixture is a separate animal.
    Don't let it bite you.
     
  7. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    New markup running lav drain and wet vent mostly in the wall. The path from the U in the trap, thru the wall, until it vent, must be under 8 ft total path with 2 inch under IPC. That is the trap arm.

    I will change my earlier picture, because I had an unneeded vent drawn in there.
     

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    Last edited: Mar 30, 2020
  8. EdNC

    EdNC New Member

    Joined:
    Mar 8, 2020
    Location:
    North Carolina
    Thanks for the help. Based on this illustration (see below) from the PDF you sent I can use my original layout but switch the position of the sink and the toilet. One (1) fixture before the 2" wet vent and the other two (2) after the 2" wet vent and not to exceed four (4) fixtures in total and the maximum distance of 8'. Thanks again.
    upload_2020-3-30_17-9-56.png
     
  9. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Nope. The laundry sink cannot be involved as part of the bathroom group. That sink needs a vent, tho it could be an AAV.
     
  10. EdNC

    EdNC New Member

    Joined:
    Mar 8, 2020
    Location:
    North Carolina
    Ok. So I will need to vent the Laundry Sink and connect it to the vent. I just want to make it as simple as possible. Will this work. Thank you

    Pole Barn Plumbing Layout 5.jpg
     
  11. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    I am not sure if this meets the wet venting requirements of an IPC bathroom group. I tend to think not, because the lavatory is not doing the wet venting.

    Alternatively, you will have to dry-vent the shower by running the shower trap arm to the wall to hit the vent. Then it can come to join the toilet drainage. In that case, the toilet would not need its own vent.
     
    EdNC likes this.
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