I am planning a kitchen remodel in which I will move the sink/dishwasher from the wall to an island about 10' from the current 2" stack in the wall. I also have a 2" iron stack running from my second floor showers through my kitchen to the basement (currently enclosed in a column that will run through the new island). I originally thought I could drain/vent the new sink through this 2" stack, but it sounds like I can't because this is a "wet" pipe and cannot also be used as a vent.

It seems that I could use the 2" stack inside the column to drain the new sink, but I will then have to run a revent up through the second floor to somewhere above the shower. Or, I could loop vent the new kitchen sink back to its original stack in the kitchen wall. The loop vent seems easier...

My question then, is there a maximum distance that I can loop vent from the new island sink to the existing kitchen drain stack? Is 10'-13' to far?

Any other recommendations?