I am moving my kitchen sink from one side of the kitchen to the other I located the 3" discharge line which is about 5' from my new sink. I have cut the concrete and i am about put a 3 x 3 x 2 tee and then run my 2" line along and up under the sink to the p trap with a 90. ( I hope this is correct) after that can I just pour concrete on top of the pipe in the trench. I am in California and worry about earth quakes. Do I need a vent. There is only a shower connected to the 3" line with a vent 4 feet away?
Thank you

According to California Plumbing Code, pipe should not be in direct contact with concrete. You have to wrap it with 6" white plastic foam wrap made specially for this purpose. The wrap is about 1/8" thick . You wrap it around the pipe with 50% overlaps and few inches above the slab. It creates space between pipe and concrete that will allow the pipe to move freely during seismic activities. Sometimes, and if you get lucky, Home Depot sells the wrap in short lengths. Otherwise, go to Ferguson Enterprises and buy a whole roll. All 600 feet of it...

Thank you for the answer I really appreciate it. Does every thing else that I am doing sound right.

I assume that 3" existing sewer pipe is horizontal pipe....

Use 3x2 Y with 2" street 45. This combination will give you proper transition angle for horizontal connection - as per Calif. Plumbing Code. Install 2"clean out above the slab. Continue to the sink. At the sink, you should have 2 x 1 1/2" San T. Sink has to have a vent. If you can, continue upwards with vent and reconnect with existing vent. If not possible, use AAV vent.

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Sink has to have a vent. If you can, continue upwards with vent and reconnect with existing vent. If not possible, use AAV vent.

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Milo, Aren't AAV's outlawed under UPC? And doesn't the new code mandate a three inch drain for a kitchen drain line? Regards, Tom

Upc only requires 2 inch ks drain. Also does not allow aav, but each state can override codes if they so choose. I have no idea what cali state codes are on aavs. I know ND allows aavs, but Montana doesn't. Both are under UPC. I would persoanally never recommend an auto vent, they only work one way and like it or not, will eventually fail. Just an opinion.
Oh, and milo is right. Do not pour concrete directly over pipe. If you have enough depth, just cover with gravel and then poor. Then you only need to wrap the pipe coming out of the floor.

Let me know if they have in fact changed the 2inch to three inch for ks drain. If so my cec instructor is definateley getting a call from me soon. Lol

AAV vent is not allowed in So.California.

As far as 3" washer / kitchen sink drain goes: today, we just started row of new track houses in San Juan Capistrano. Blueprints call for 2" pipe for kitchen and washer drains...