Does this wet vent meet code?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by pghsebring, Oct 7, 2011.

  1. pghsebring

    pghsebring DIY Member

    Messages:
    97
    Location:
    Ohio
    Well, i'm just about finished with my main bathroom (other thread), now it's about time to tackle the basement bathroom. I found this picture on this site:

    [​IMG]

    Now, i want to know if it can be set up like this instead:

    [​IMG]

    Now, that vent is going up 2 stories, and into the attic. I want to know if i should run it over to the 2" vent from my other full bathroom (ie, join them in attic) and send them both out the existing hole in the roof (one 2" vent), or if i should punch another hole in the roof, and run each out a separate hole? If the answer is "separate holes," that new vent is running up through an exterior wall, and if i went straight out the roof, would be pretty close to the eave/edge of roof. Is this ok? Is there a required distance from the edge of the roof for a vent penetration? If it must be moved/offset, what is the best way to do this - a couple of 90s? Supports needed in any way?

    Thanks in advance.
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,416
    Location:
    Bothell, Washington
    The first drawing show the toilet downstream.

    Then you changed the drawing to have the toilet upstream of everything. Whenever the toilet is flushed, it will siphon the shower trap. Where the toilet is placed in the system is "very" important.

    2nd drawing is wrong, wrong, wrong.
  3. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,311
    Location:
    Maine
    You should ask your plumbing inspector. Though Terry has a valid point, in a lot of places that are under the IPC, we can now wet vent in any order so technically the 2nd drawing may be ok. At least it is here.
  4. Gary in NJ

    Gary in NJ New Member

    Messages:
    90
    Location:
    NJ
    Is there any way that you can vent behind the WC and tie it back (up and over to) the existing vent?
  5. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    I am not an engineer...but I suspect that in todays world of 1.6 GPF, soon to be 1.28 GPF, it may not be such a big deal to flush a toilet past a tub. But your inspector will have the final say!
  6. Terry

    Terry Administrator Staff Member

    Messages:
    15,416
    Location:
    Bothell, Washington
    Except that when toilets were five gallons, the water went by very slowly.
    With the 1.28, they have sped up the flush, and now the water will skip across a fixture cross and push water out of an opposing bowl. That never, ever happened with the five gallon bowls. But it does with the new 1.28 gallon bowls. If anything, the plumbing needs to be much better for the new bowls. It's sudden and deadly.
  7. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,311
    Location:
    Maine
    I wondered and then argued the point when they changed the rule but my argument fell of deaf ears. Apparently the boys that write the code know better than us dumb plumbers. Whenever possible I have always favored having an upstream fixture wash the toilet drain but again, nobody seems to see the value in that anymore. I still do it when possible though. It saves a lot of return calls.
  8. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,185
    Location:
    NW Ontario, Canada
    Exactly, and then don't argue code with him/her.

    There are two things in both pictures that my inspector would never allow. He made me add a vent for the shower, would not let me wet vent it. The other thing he never let me get away with is to Tee or elbow on the same horizontal plane. I had to use a combination of a rolled Y and rolled elbow to form a drop.
  9. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,311
    Location:
    Maine
    Well, the distance from trap to the wet vent comes into play but if the shower (and any other bath group fixtures) are within the prescribed distances than the inspector would have to approve it. Your Canadian code is a bit different though. If you use a rolled wye or combo on the horizontal then you negate the wet vent so yes, yo then need to individually bent the shower
  10. pghsebring

    pghsebring DIY Member

    Messages:
    97
    Location:
    Ohio
    2009 IPC here. So it may be allowed?
  11. pghsebring

    pghsebring DIY Member

    Messages:
    97
    Location:
    Ohio
    Let me look into that...but the main problem is the toilet is on the far side of the bathroom from where the drain line is.

    ...but even if i do, isn't the shower still downstream, and problem terry references still there?

    Here's another question....is there any limit on the length of the arm for the WC? 8 ft for example?
  12. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,253
    Location:
    Cave Creek, Arizona
    The toilet flowing past the shower, (in UPC terminology it is a 'major fixture' over a 'minor' one), which is the problem. ANY time that occurs the 'minor' fixture must have its own independent vent to eliminate the problem. If the "code" does not require a vent for the toilet, then it also may not have a length restriction, because the two go together. The IPC is more concerned with inexpensive installation, so it allows many variations which the UPC does not.
    Last edited: Oct 8, 2011
  13. Terry

    Terry Administrator Staff Member

    Messages:
    15,416
    Location:
    Bothell, Washington
    In the UPC code, the toilet must be vented within six feet.
    It's simple to install plumbing for that bath that would pass a UPC inspection. Just vent the shower. It's not going to kill you to spend $10 more.
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