Laundry tub/washer sanitary tee question

[nittanylion74]

I'm at a loss, created an account because I can't find the answer I need (which is very surprising). I have 2 options to connect a washer standpipe and laundry tub.

Option #1 (stacking tees) in the picture below I believe is correct, but puts my laundry tub rough in at 20". Option #2 (double tee) will give me the height I need, but I'm pretty sure is bad practice at least and against code at worst. Anyone have any suggestions? I'm installing a wall mount laundry tub, could I get away with a 20" rough in?

If it's unclear, below the fitting in the photo is a 45, 2 inch pvc and another 45 into 3 inch cast iron hub donut. So there's no wiggle room there.

 

[Terry]

In most codes laundry sinks can't wet vent over a washer, they need their own vent.
This one is installed with a washer box that has hammer arrestors. The revent is six inches above the highest flood level.

You can also use a double fixture cross, not a double sancross.

 

[Sponsor]

 

[nittanylion74]

Thanks for the reply. I'm confused on the difference between the double sani-t and the double fixture cross. Idk of I've ever seen one. Will that prevent washer/laundry tub crossover at the t?

Venting the sink separately won't be an issue, thanks for the advice.