Sewage Ejector Venting

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by rickseville, Dec 10, 2012.

  1. rickseville

    rickseville New Member

    Messages:
    7
    Location:
    atlanta
    I'm planning to finish my basement but I've run into a problem. I originally thought the builder stubbed out two pipes that vented out to the roof: one for the bathroom fixtures, and one next to the ejector pit. Upon further inspection, I found the vent pipe next to the ejector pit actually runs along the joist and ties into the bathroom vent pipe. Which means I only have one 2 inch pipe vented to the roof. I wasn't sure if code called for a dedicated vent line for the sewage ejector. If so, I seem to be short one vent line. So my questions are:

    1. Can I use the one vent line to tie into the bathroom fixtures (WC, lav, tub) and the sewage ejector?
    2. If not, what would be the best solution? Using the vent line for the ejector and AAVs for the fixtures?

    Any suggestions would be appreciated.
  2. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,260
    Location:
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    Most sewage basins require a dedicated 2" vent. The vent does not have to go up directly above the basin. Running a new vent through the inside of an existing wall up through the attic and roof is fairly easy in many homes. If running inside the wall does not work, it can be ran it up through the back corner of a closet or pantry, where it can be boxed it in with some simple framing and drywall if need be.
  3. rickseville

    rickseville New Member

    Messages:
    7
    Location:
    atlanta
    Thanks, cacher_chick. I'm trying to avoid running a new vent pipe to the roof because it would have to go up through 2 floors. Could using air admittance valves for the lav/WC/tub be an option? This may be a stupid question, but how about venting the lav/WC/tub and the sewage pit with the one vent line to roof, but having air admittance valves for the lav/WC/tub as added insurance?

    Thanks.
  4. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
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    Location:
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    If the house has a 3" building drain, it should have a 3" vent or multiple vents which when added up equal the area of a 3" vent.

    There is little to say that venting through the existing vent through roof might not work, but it would not meet code and thus not pass an inspection. The code and inspection process exists to ensure that the installation will work properly and in a safe manner.

    There are very few places where I find using an AAV is the way to go. When an AAV is used it must be installed in a location that will prevent it from ever becoming contaminated with a backup; where any sewer gas leak will be immediately detected, and in a position that will allow it to be easily and immediately replaced. I would much rather put in a proper vent and never have to worry about it again.
    Last edited: Dec 13, 2012
  5. rickseville

    rickseville New Member

    Messages:
    7
    Location:
    atlanta
    Thanks, again. I may be able to find a way to add a 1.5 inch vent pipe for the lav/wc/tub up and out through my garage roof so I don't have to go up 2 floors. I would have to make a long horizontal run. Then I can use the existing 2 inch vent pipe as a dedicated line for the ejector. Is there any code I should be aware of for adding the new vent pipe?

    On another note, I'm just curious on how the builder passed the plumbing inspection when they obviously roughed it out with one vent line from the roof going to a stub out next to the lav and a stub out above the ejector pit.

    Thanks.
  6. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    You cannot use an AAV on the ejector basin anyways, the level in the pit rises and falls so air will be displaced not just drawn in... and AAV only allows are movement in one direction.
  7. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,267
    Location:
    Maine

    Actually, yes you can. You can find the engineered drawing on Studor's web site
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,048
    Location:
    Cave Creek, Arizona
    I have NEVER installed a "vent through the roof" for an ejector pump system. Connecting to the existing vent is perfectly adequate, although it might not be "propeer" in some areas. The only reason for a dedicated vent is to minimize sewer gas odors when the pit's cover loses its seal. For that reason, your "vent for the pit and AAVs for the fixtures" would be a senseless solution.
  9. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    So the people who make the crap-vent say it's a good idea and everyone who makes basins and ejectors says it is not?
  10. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,267
    Location:
    Maine
    Apparently...................Yes. Hey, I didn't say it was a good idea and everyone is well aware of how I feel about AAV's but, the drawing is and engineered drawing and is acceptable to the IPC and the UPC so as much as I hate the idea, it does meet code requirements. Here's my question though. Why bother with the AAV at all as they have it shown?
  11. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,048
    Location:
    Cave Creek, Arizona
    quote; So the people who make the crap-vent say it's a good idea and everyone who makes basins and ejectors says it is not?

    Did you read the entire section?
    1. It says that you have to get the building department's approval to use a Studor vent on an ejecto.
    2. THey still have a vent from the tank but is is connected back to the sewer after the pump discharge connection, which is a recipe for disaster if the sewer clogs because ALL the building sewage will flow back through that pipe into the pit and flood the basement.
    3. A P.A.P.A. valve would minimimze positive pressures, but it is for commercial use only. I guess they figure a homeowner would object to the valve emitting sewer gas into the basement.
  12. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,260
    Location:
    Land of Cheese


    The issue you would probably run into with this is that the vent must be run at 2% or more grade to drain back to the fixture drains. The vent can also have no "jogs" that would create a trap for moisture/condensation in the pipe. It must be able to flow just like a drain.

    If you were going to connect the pit to the existing venting system, the connection would need to be made above the flood rim of the highest connected fixtures, so in many houses it would very likely be just as easy to run a new vent.
  13. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,048
    Location:
    Cave Creek, Arizona
    quote; the connection would need to be made above the flood rim of the highest connected fixtures, so in many houses it would very likely be just as easy to run a new vent.

    This is a "preinstalled" vent for the basement unit so it WOULD be connected properly to the upper level vent system, unless the installer were incompetent, but if that were the case, they would probably NOT have installed it in the first place.
  14. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,260
    Location:
    Land of Cheese
    I missed the line where he said that the was an unused 2" vent in the basement. So if the listing and labeling on the basin calls for a dedicated 2" vent, HJ would just ignore it?
  15. Terry

    Terry Administrator Staff Member

    Messages:
    15,298
    Location:
    Bothell, Washington
    What's wrong with placing the vent on the outside of the home, and the penetrating the roof under the eave? A little bit of paint and it looks like a downspout.

    I did that in Seattle, from the basement, past the next two stories and out through the roof.
    I did have to tie myself off working on that steep roof.
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