Uniform Plumbing Code and AAVs

Discussion in 'UPC Plumbing Code Questions' started by IPDQKWID, Nov 3, 2017.

  1. IPDQKWID

    IPDQKWID New Member

    Joined:
    Jul 14, 2016
    Location:
    Minnesota
    Help. Having looked over the plumbing codes for Minnesota, I think they follow the UPC. The code is published in chapters, with sections such as 310, 702, 910, etc. Where in the world do I find references to AAVs? I don't want to ask the inspector yet, as I don't trust him. He has something against homeowners doing their own remodel.
    And maybe an unrelated question, but if the max CFUs on a vent pipe was 24, and you counted 19-20 as the final outcome on your project, would you professionals do a 3" vent out the roof, or be good with a 2" vent? Thank you.
     
  2. Terry

    Terry Administrator Staff Member

    Joined:
    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    Venting needs the same area as the waste.
    If you have 3" going out, then either a single 3" or we also do two 2" and one 1.5" which combines to make up the same area as a 3".
    I would ask the inspector about using an AAV first. Most are okay with it. You need at least one vent through the roof though.
     
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  4. hj

    hj Moderator & Master Plumber Staff Member

    Joined:
    Aug 31, 2004
    Occupation:
    Plumber
    Location:
    Cave Creek, Arizona
    AAVs are usually a "local code option addendum" to the UPC.
     
  5. hammerpocket

    hammerpocket New Member

    Joined:
    Sep 11, 2017
    Location:
    Minnesota
    As of November 2017, they are not allowed in Minnesota.
     
  6. IPDQKWID

    IPDQKWID New Member

    Joined:
    Jul 14, 2016
    Location:
    Minnesota
    Thank you for the replies. At least I can trust the answers here. I have another question regarding venting, and other answers I find online are all over the place. Does the main stack need to be straight? Comes up out of the cement slab on the first level, toilet comes into it on the second floor, at this point it will be difficult to keep the stack straight all the way out the roof. Is that a code thing? I may have to jog the vent stack over a few inches to avoid moving the ceiling joist upstairs.
    It seems I'm building the plumbing around the addition, instead of building the addition around the plumbing.
    Thank you/
     
  7. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    No.

    1. 45 degrees or more from level is considered vertical.
    2. Drains can be horizontal, as long as they are tipped downhill a minimum of 1/4 inch per ft. The same for vents above 6 inches above the flood level.
    3. When drains are transitioning from vertical to horizontal, 45s or a long sweep must be used. That would usually be the same for horizontal to horizontal. Going from horizontal to vertical can use shorter bends, because clogs seldom happen there.
    4. For vents, they must be vertical in the interval below 6 inches below the flood level of any fixtures that vent serves. The flood level is where water would spill onto the floor if the drain clogged.
    5. You must go no more than 135 degrees of bends for non-vertical drains without a cleanout.

    I may have gotten something off, and I know there is more to it. I am not a plumber.
     
  8. hj

    hj Moderator & Master Plumber Staff Member

    Joined:
    Aug 31, 2004
    Occupation:
    Plumber
    Location:
    Cave Creek, Arizona
    quote; they must be vertical in the interval below 6 inches below the flood level of any fixtures that vent serves.
    That should be 6" ABOVE the flood level. And the second requirement is usually ALSO at least 42" above the floor, whichever is HIGHEST.
     
  9. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    Your vent line could accumulate condensation or receive precipitation from above...it needs to be able to drain and remain open. Often, in colder climates, the section that actually penetrates the roof (and a ways beneath it)may need to be upsized to prevent hoar frost from closing it off on really cold days. You can get a lot of steam trying to escape when say doing laundry, dishes, a long shower, etc. If it's cold enough, the thing could frost shut.
     
  10. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    https://www.revisor.mn.gov/rules/?id=4714.0905&format=pdf
    UPC section 905.3 is amended to read as follows: 905.3 Vent Pipe Rise. Except as provided elsewhere in this code, each vent shall rise vertically to a point not less than 6 inches (152 mm) above the flood-level rim of the fixture served before offsetting horizontally, and where two or more vent pipes converge, each such vent pipe shall rise to a point not less than 6 inches (152 mm) in height above the flood-level rim of the plumbing fixture it serves before being connected to any other vent.​
     
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