I have a laundry tub that sits 1 1/2 feet from a vent stack. The tub currently is one of those concrete two section tubs. I'm removing it and replacing with a single resin tub.

The current drainage for the tub is directly into the vent stack with a P trap.

The bottom of the new tub sits higher than the old concrete tub, so I want to extend the drain pipe out of the bottom of the new tub, into the P trap, so the horizonatl pipe off the P will enter the vent at a near horizontal position, (as I understand it must).

I am wondering how long of a drain pipe is allowed. I think I need about a 10" drain pipe, which would put the bottom of the P trap pipe at approx 6 " off of the floor.

Is there any code issue with having a 10 " drain pipe, and for having the P trap as close as 6" to the floor?