I am seeking some input for a kitchen island remodel, where due to countertop changes new cabinets and plumbing became necessary. Nothing lines up new - old. Trying to simplify and minimize / avoid drilling more holes in the rafters below.
Old setup from the seventies.
Two sinks, two dishwashers. Each with 1 1/2 drain via a drum, going as two arms into a single 2" inch waste line which about ten feet furter drops down five feet into large cast iron. The drum barrel for one of the dishwashers were not in use anymore and they emptied into a disposal. The other one lacks the always recommended high dran loop.
I was hoping to simplify this and have each dishwasher emptying into their adjacent sink.
As the center of the island is open and servicable (made access panels) and not tiled, just an extra layer of plywood, I was hoping to use that void as a service corridor for all water, drain and electrical. (Versus drillng through cabinet bottoms and worse tile flooring)
So I could see 1 1/2 below the sink, p trap into center of island, then run 2x two inch down 10 feet over to the cast iron, with cleanout offset at the end off the 10 ft line etc.
But space is limited as rafters are 12 on center. The old setup seemed ok with a single 2" line. And no p traps in any cabinet, only drums under floor. ( no lnger code as i read it)
So my most simplified idea became, mixing old and new:
1x 2" 10 ft line to center of the island, 2" p trap under the floor, 2" coming up in the void with two wyes of 1 1/2 that go to each sink plus dishwasher and high on top of that 2" pipe, unone of those new air admittance valves.
I have looked at code and been concerned with the DFU load where dishwashers and sinks each are counted as two units, even though never three or four would be emptied at the same time.
I also can't find confirmation if I can run a single 2" p trap under the floor, vs two 1 1/2 p traps under the sink or the floor. Or is a p trap under each sink now mandatory. In old island plumbing reference code it was stated p traps had to be under the floor for venting purpose. I'd be very happy to that, more room in the cabinet.
Additionaly some web stuff points to that I would need to run 3" horizontal, come up with three inch in the center of the island and two inch under each the sink. To me this seems overkill since there's no bath or toilet involved ... and the old setup was fully functional.
Additionally here s refernce to right sizing vs upsizing because one needs the scouring and flushing through action of any possible particles, ... That would just cling on if one were to oversize.
Thank you for reading and any recommendations and references people may have.
I am hoping to keep it simple and functional; think my idea should work but would hate to make a mistake or have to tear it out later due to some practical oversight or code issue.
Old setup from the seventies.
Two sinks, two dishwashers. Each with 1 1/2 drain via a drum, going as two arms into a single 2" inch waste line which about ten feet furter drops down five feet into large cast iron. The drum barrel for one of the dishwashers were not in use anymore and they emptied into a disposal. The other one lacks the always recommended high dran loop.
I was hoping to simplify this and have each dishwasher emptying into their adjacent sink.
As the center of the island is open and servicable (made access panels) and not tiled, just an extra layer of plywood, I was hoping to use that void as a service corridor for all water, drain and electrical. (Versus drillng through cabinet bottoms and worse tile flooring)
So I could see 1 1/2 below the sink, p trap into center of island, then run 2x two inch down 10 feet over to the cast iron, with cleanout offset at the end off the 10 ft line etc.
But space is limited as rafters are 12 on center. The old setup seemed ok with a single 2" line. And no p traps in any cabinet, only drums under floor. ( no lnger code as i read it)
So my most simplified idea became, mixing old and new:
1x 2" 10 ft line to center of the island, 2" p trap under the floor, 2" coming up in the void with two wyes of 1 1/2 that go to each sink plus dishwasher and high on top of that 2" pipe, unone of those new air admittance valves.
I have looked at code and been concerned with the DFU load where dishwashers and sinks each are counted as two units, even though never three or four would be emptied at the same time.
I also can't find confirmation if I can run a single 2" p trap under the floor, vs two 1 1/2 p traps under the sink or the floor. Or is a p trap under each sink now mandatory. In old island plumbing reference code it was stated p traps had to be under the floor for venting purpose. I'd be very happy to that, more room in the cabinet.
Additionaly some web stuff points to that I would need to run 3" horizontal, come up with three inch in the center of the island and two inch under each the sink. To me this seems overkill since there's no bath or toilet involved ... and the old setup was fully functional.
Additionally here s refernce to right sizing vs upsizing because one needs the scouring and flushing through action of any possible particles, ... That would just cling on if one were to oversize.
Thank you for reading and any recommendations and references people may have.
I am hoping to keep it simple and functional; think my idea should work but would hate to make a mistake or have to tear it out later due to some practical oversight or code issue.