Trap Arm Critical Distance - Would this meet code?

[Jeff Sel]

We are relocating our kitchen sink and I was considering reusing the existing vent stack. If I tapped the new sink drain into the existing 2" drain pipe it would leave a 4' horizontal run before reaching the vertical vent stack. Would this be considered a wet vent with no upstream fixtures and does it meet code?
Also I believe everything from this tie to the 2" sink trap would be considered part of the trap arm but I do not know if the 20" vertical pipe rising from the ground to the trap elevation would be considered part of the trap arm. Everything I have read refers to horizontal distance but I did find code section 3602.3 talks about vertical legs for fixture drains and would would seem to indicate if I drop the vertical pipe size down to 1.5 " pipe and trap then my arrangement would comply as the allowed length of "C" is then unlimited.
All of this plumbing is under a concrete slab and inside block walls so I am looking to minimize the amount of concrete cutting & repairs if possible.

 

[hj]

You should be looking at the section that prohibits "S" traps, not the one about horizontal distances.

 

[Sponsor]

 

[Jeff Sel]

You should be looking at the section that prohibits "S" traps, not the one about horizontal distances.

So basically the vertical drop turns this arrangement into an S trap and these are prohibited by code.

Using the existing roof penetration and abandoning the in floor & wall portions of the unneeded drain\vent pipe could I connect to the existing drain line and make use of the vent pipe from the attic up?

 

[Jadnashua]

The trap arm cannot go vertical before it is vented, and depending on the diameter of the pipe, that vent must occur within a certain distance.

 

[hj]

That appears to be correct, but you also need a cleanout tee in the line somewhere.

 

[Jeff Sel]

Thanks for your help.

HJ I was going to include a cleanout beneath the sink. From there to where I will tap into the existing pipe is going to be below the concrete slab.
Would I need an accessible cleanout beneath the slab?

If I am looking at the correct code section this time 708.3.3 Changes of direction.
Cleanouts shall be installed at each change of direction greater than 45 degrees (0.79 rad) in the building sewer,building drain and horizontal waste or soil lines. Where more than one change of direction occurs in a run of piping, only one cleanout shall be required for each 40 feet (12 192 mm) of developed length of the drainage piping.
I thought that this one cleanout would suffice since the run is under 40'

The only way I can see to add additional cleanouts that do not stick up from the middle of the floor would be to keep the original drain\vent pipe and install a cleanout in the original vertical vent riser such as this image but I would prefer not to unless its required. Would adding this additional cleanout really make snaking any easier?

this line any easier?