Drain for new sink - connect to existing drain

[lbspartx]

Hello, I'm trying to figure out how to connect a 1 1/2 drain for a new sink to my existing plumbing.

I think I can connect the new drain line to the existing 2" drain line for the bathtub (which I'm assuming should have its own vent) with a wye as shown in the attached sketch. The new sink drain line would have an air admittance valve because I can't tie into any of the existing vents.

I'd be running the new drain line through the open web floor joists so I won't have to cut any framing or anything. I'd use a long sweep elbow for the 90 deg bend shown in the sketch or try to reroute it with 2 45 deg elbows instead of the one 90 deg bend

Can someone tell me if this will work (and perhaps be generally code compliant?) as long as I slope the new drain pipe properly (1/4 inch/ft)? From what I can tell researching online, it is okay to have both the tub and new sink on the existing 2" drain line.

Thanks

 

[CT18]

It would be code for me to do that. I assume the existing tub has its own vent. Either way in my area we can wet vent non toilet with lav

 

[lbspartx]

Great, good to hear my plan is do-able. And just so I understand, the drain would still be considered wet vented because the air admittance valve on the new sink doesn't technically qualify as venting?

I haven't actually seen it but I'm pretty sure the tub has a vent that connects to the main vent coming off the 3" drain line.

Thanks for the info!