I'm trying to add a sink in our laundry room. My questions are mostly about the drain and vent. I understand the ideal would be as this photo that I got from other post on this site.
In this photo, the black lines I have added are to show what is already in place but you cannot see. The two vertical lines at left and right are studs. The vertical box next to right stud is gas pipe. Diameters are standpipe (2"), drain-vent below clean out (2.5"), vent above clean out (2").
I can easily T into drain-vent pipe for sink drain, and I can easily connect and run hot and cold water lines for sink. My problems are with sink drain and vent for washer standpipe. The only place I could possibly put additional vent would be right after trap for standpipe to left of studs. Then I would need to run it vertical and cut through studs to connect with vent.
My main question for you experts: is that really necessary? Please help me understand risks if I just T sink drain into drain-vent pipe above where line connects from washer and below clean out. Where the standpipe trap now connects to the drain-vent is at a downward Y, so I'm not seeing much risk of the water from sink drain siphoning from standpipe trap.
Thanks in advance for your help!
P.S. I'm sorry I could not figure out how to delete this additional image where I first incorrectly showed T instead of Y now connecting to drain-vent.
In this photo, the black lines I have added are to show what is already in place but you cannot see. The two vertical lines at left and right are studs. The vertical box next to right stud is gas pipe. Diameters are standpipe (2"), drain-vent below clean out (2.5"), vent above clean out (2").
I can easily T into drain-vent pipe for sink drain, and I can easily connect and run hot and cold water lines for sink. My problems are with sink drain and vent for washer standpipe. The only place I could possibly put additional vent would be right after trap for standpipe to left of studs. Then I would need to run it vertical and cut through studs to connect with vent.
My main question for you experts: is that really necessary? Please help me understand risks if I just T sink drain into drain-vent pipe above where line connects from washer and below clean out. Where the standpipe trap now connects to the drain-vent is at a downward Y, so I'm not seeing much risk of the water from sink drain siphoning from standpipe trap.
Thanks in advance for your help!
P.S. I'm sorry I could not figure out how to delete this additional image where I first incorrectly showed T instead of Y now connecting to drain-vent.