DWV Sanitary Tee question

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by baldmagicguy, Aug 23, 2008.

  1. baldmagicguy

    baldmagicguy New Member

    Messages:
    2
    Greetings! I'm hoping one of you Master Plumbers out there can answer a question for me.

    I'm going through the code book and I understand that it's a no-no to put a sanitary tee on its back. I can understand why this is forbidden if the vertical connection is a drain. A combo would be the solution for that scenario.

    What a don't understand (and maybe my understanding is flawed) is why can't you use a sanitary tee on it's back if the vertical connection is a vent? This would be a crown vent, right? And a crown vent, as long as it's more than 2 pipe size diameters away from a trap, is allowed... am I still correct?

    Thanks in advance for sharing your vast knowledge.

    Regards,
    Marty
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,873
    Location:
    Cave Creek, Arizona
    vents

    A crown vent comes off the inverted U bend of an "S" trap and is NEVER permitted. The codes SPECIFY that any fitting below the overflow level of a fixture MUST be assumed to be a drain fitting, not a vent fitting, because it will fill with water when the line is obstructed. In this case you are trying to be logical and the codes are not necessarily logical.
  3. baldmagicguy

    baldmagicguy New Member

    Messages:
    2
    vents

    hj,

    Thanks for the reply. LOL! I drive my wife nuts all the time by being logical. I was reading through the code book trying to make sense of some of the rules. Just doing this has increased my respect for plumbers tenfold. You guys really have your work cut out for you.

    Thanks for the explanation. I was wondering what evil might be lurking by putting a sanitary tee on its back.

    Regards,
    Marty
  4. Terry

    Terry Administrator Staff Member

    Messages:
    15,146
    Location:
    Bothell, Washington
    One explanation I heard was
    Someone may come by later and use a vent for a waste line, so anything below grade must be run with waste, and not vent fittings.

    Of course in plumbing, ask ten inspectors and you will get a variety of answers. Most pretty close.
  5. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    IPC allows a san tee to be used for vertical venting as long as it is dry.
  6. Terry

    Terry Administrator Staff Member

    Messages:
    15,146
    Location:
    Bothell, Washington
    UPC requires the use of a santee if it's vertical.
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,873
    Location:
    Cave Creek, Arizona
    ipc

    A sanitary tee is cheaper than a combination Y-1/8 bend, that is why the IPC allows it. Many things in the code anticipate future actions, which is why the horizontal run or connection of an individual vent has to be at least 42" above the floor. In case a 36" kitchen sink is eventually connected to it and thus the 6" above the rim will be maintained.
  8. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    HJ, are you saying that the IPC guys were bought off by the manufacturers:eek:
  9. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,873
    Location:
    Cave Creek, Arizona
    Ipc

    NO, the contractors. The UPC and IPC had a merger agreement, but when the IPC contractors learned that they would have to go back to doing good plumbing, they tore up the agreement.
  10. patrick88

    patrick88 Plumber

    Messages:
    836
    Location:
    Webster Ma.

    LOL That is too funny
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