Two Bathroom Sinks - Both Need Individual Vent?

[crbdrbonline]

Hello. It has been a while since I have had to deal with vents and wanted to know if the green plumbing is necessary in addition to the red vent. I believe it is but wanted to make sure.

I have two bathroom sinks that exit vertically with 2" PVC pipe directly into the basement and are connected to a 2" waste line as pictured. The sinks are 48" apart if that matters in this scenario.

I appreciate any help.

 

[wwhitney]

As drawn, with the black lines carrying drainage, the green line is definitely required as a vent for the righthand sink. And the red line must be a dedicated vent, no drainage coming down from above. [For good measure, note that the fiting where the red or green vent joins the black line as it turns from horizontal to vertical needs to be a sanitary tee, not a wye or combo.]

Also, just looking at things locally here, everything above the bottom horizontal 2" line could be sized at 1-1/2" for bathroom lavatories, both the drains and vents.

Cheers, Wayne

 

[Sponsor]

 

[crbdrbonline]

As drawn, with the black lines carrying drainage, the green line is definitely required as a vent for the righthand sink. And the red line must be a dedicated vent, no drainage coming down from above. [For good measure, note that the fiting where the red or green vent joins the black line as it turns from horizontal to vertical needs to be a sanitary tee, not a wye or combo.]

Also, just looking at things locally here, everything above the bottom horizontal 2" line could be sized at 1-1/2" for bathroom lavatories, both the drains and vents.

Cheers, Wayne

Ok. Thank you very much for replying, and I will do as you stated.

All the “black” 2” plumbing is already in place and installed by a licensed plumber. This is all dedicated to just 2 sinks (including the red/green dry vents) - There is also nothing upstream (right) except for a cleanout. That 2” drain line is located in the basement and the two black vertical pipes to the sinks extend up to the first floor.

For various reasons, I have to do the vent in this location, and I just wasn’t sure if one vent could address both traps.

Just out of curiosity, could one vent could serve both if it were the trap arms (of acceptable length) going to the vent? Is it the fact that the trap arms connect to a vertical drain first that creates the need to vent each?

 

[wwhitney]

Each trap arm needs to be vented before the trap arm falls more than one pipe diameter. So yes, it is the drain turning downwards that means the trap arm needs to be vented at that point, no later.

If each stub-out connected directly to a horizontal trap arm in the wall, then a single dry vent takeoff between the two traps would dry vent the upstream trap, and wet vent the downstream trap.

Cheers, Wayne

 

[Terry]

 

[Jeff H Young]

Hello. It has been a while since I have had to deal with vents and wanted to know if the green plumbing is necessary in addition to the red vent. I believe it is but wanted to make sure.

I have two bathroom sinks that exit vertically with 2" PVC pipe directly into the basement and are connected to a 2" waste line as pictured. The sinks are 48" apart if that matters in this scenario.

I appreciate any help.

yes just like you drawit is perfect ! easy solution

 

[crbdrbonline]

Each trap arm needs to be vented before the trap arm falls more than one pipe diameter. So yes, it is the drain turning downwards that means the trap arm needs to be vented at that point, no later.

If each stub-out connected directly to a horizontal trap arm in the wall, then a single dry vent takeoff between the two traps would dry vent the upstream trap, and wet vent the downstream trap.

Cheers, Wayne

Thank you for providing that additional reasoning.

 

[crbdrbonline]

Thanks, that last picture is basically what I was forced into. I just wanted to make sure and then understand why that right vent was necessary. I think I have it now. I appreciate it.

 

[crbdrbonline]

yes just like you drawit is perfect ! easy solution

Cool. Thanks!

 

[Jeff H Young]

it keeps the trap from siphoning all p traps require a vent. having another vent nearby is of little to no help but still doesn't meet any code.