Running a plumbing vent line through kitchen cabinets

[M3 Pete]

I have a slab on grade house, with a kitchen sewer drain that comes out of the slab approximately 6 feet from a wall. The sewer vent used to go straight up from the drain, but we removed the wall, and now want to extend the peninsula to the wall that is 6 feet away. I want to put a kitchen sink right on top of that drain, and run the vent through the base cabinet over to the wall, 6 feet from the drain. The drain appears to be 2", and my plumber tells me that he cannot run the vent pipe horizontally more than 5 feet unless it is above the kitchen sink. California does not allow an AAV. Any creative ideas to solve this? Can I run the P trap towards the wall and hook up the vent at 5 feet and then reverse the drain back to the sewer drain in the floor?

I know an island vent could be done, but I'm trying to avoid tearing up the concrete on my post-tension slab.

 

[Terry]

A 1.5" trap arm can run 42"
A 2" trap arm can run 60"
You could run the waste below venting over as far as possible, then trap arm back the allowable distance, then off the top of the santee, run at a 45 to where you need to be. A 45 is considered vertical.

Did that make sense?
The waste with cleanout can go horizontal.
It's the vent they worry about.

 

[Sponsor]

 

[hj]

I use 60s and have never had an inspector call it "horizontal".

 

[M3 Pete]

A 1.5" trap arm can run 42"
A 2" trap arm can run 60"
You could run the waste below venting over as far as possible, then trap arm back the allowable distance, then off the top of the santee, run at a 45 to where you need to be. A 45 is considered vertical.

Did that make sense?
The waste with cleanout can go horizontal.
It's the vent they worry about.

I spoke to my plumber, and he thinks we can position the trap towards the wall, and get the end of the trap within 60" of the wall for the trap arm, which will go into a santee at the wall where the vent will go vertical, then the waste will reverse back to the drain pipe in the slab. We plan to put a cleanout in at least two places, at the wall, and somewhere under the sink. It is a lot of bends, so I hope I am not creating a headache for clogs.

I guess we cannot go horizontal with the vent at all if it is 6" below the flood level of the fixture.

Is this what you were saying?

 

[Terry]

Sounds about right.

 

[M3 Pete]

So I'm just about to get the counters and the sink. For the 2 inch trap arm, where does the 2 inch have to start? I will only have a disposal in the single-bowl sink. Can I run the disposal into a 1.5 inch P trap and then into the 2 inch pipe? Or does the P trap have to be 2 inch?

And what is the recommendation for the P trap, ABS or PVC?

 

[Terry]

The p-trap can be a tubular 1.5" trap.
The trap arm is 2" reduced down to 1.5" for the trap adapter. You should h ave a 2" cleanout on the arm too.