I'm attempting to add a bathroom to my 3rd floor. I have to run a 3" waste line through a wall on floor 2, down into the ceiling of floor 1 to tie into the existing 3" waste line connecting the other 2 toilets on floor 2.
Because of the existing constraints, my question is can I vent off the top of the 90 elbow I'm using off the toilet waste pipe that turns the waste pipe vertical down the wall to vent the toilet and shower.
As the image shows I have about 1'4" from center to center of toilet to turn down the wall where I'd like to vent off the top. I have about 4'2" from shower drain to long sweep sanitary wye tie into the 3" waste pipe.
Would this configuration pass code?
Best Answer
Under IPC, not the way you show it. Don't know what code you are under, but they are often similar, while differing in details.
You could have a vent in that location, but there are two immediate problems I see with how you have drawn it.
Vent must be "vertical" (actual definition of "vertical" for this application is 45 degrees or more upward) to 6" above the flood rim of the highest fixture on the floor served - you appear to show it travlling horizontally well below that level. It also cannot combine with any other vents below that level, so if the existing vent passes out through the roof below that level you'll need a new vent out the roof.
Dry vent Tee (or combo Wye) connection to dry vent stack is upside down. For a dry vent connection the bend goes upwards, and the entire vent is sloped to drain back to the fixture drains it serves.