Can I rough plumb a double vanity like this?

Javelin

Many have been so helpful with my bigger discussion on my master bath plumbing, but now a quick question.. didn't want to bury it in the other thread since it can stand alone…

I have a need to put the main drain of a double vanity TOWARD (but not close enough to freeze or anything) an exterior wall. Could I plumb it similar to attached? I'd add a clean out JIC as the line still goes under the floor for about 7 feet before it ties into the 4" main stack.

Can I plumb it like this rather than the traditional double waste T? These are 1.5" PVC waste/vents to be clear.

THANK YOU!

HVACNUT

I don't do plumbing, so I don't understand the connected loop on the left side. Can't the top and bottom tee's for the left hand sink just be 90° els?

And I think the TY on the main vent is upside down.

kcopp

Venting needs to be 6" above the flood rim level before going horizontal.

I also dont get the 90s on the ends…

Yes the Tee Wye on the vent is upside down.

Kaos

That loops on the ends are not needed. Raise the vent above flood rim and just run it up, it doesn't need to connect to the drain on the wall side.

Mad Dog_2

As the guys said.

1. Bottom.of vent header needs to be a minimum of 6" Bove the Flood level rim of the fixtures.
2. You need to dump waste in to a wye & 1/8th bend or a Long Turn Tee Wye. Sanitary Tees (Tee wyes) not code or good practice.
3. The Circuit type venting you show is how we pipe commercial jobs. That's the way I would do it. Mad Dog

Mad Dog_2

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You don't "need" the last loop vented portion, but I like the additional circulation and an accessible Clean out plug to hit the common waste run. Mad Dog

Mad Dog_2

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This is nice too and less piping & drilling. Mad Dog

Mad Dog_2

Forgot the Cleanout on right lav...They are a Godsend when you've done alot of sewer & drain cleaning. Mad Dog

Javelin

Thank you all so much for your expert advice! I've reworked the model with:

1. Colors - white is 1.5", light aqua is 2" with 1.5" inlets, dark aqua is 2"
2. I made the waste dump a long turn
3. added suggested clean outs above san-tees…
4. Reverse the vent Tee Wye
5. I put a sink in for reference - NOT in proper position. In reality, we're probably going to do a double console sink.. so not even sure the cleanouts will be easily accessible without taking off a counter or something, but still, might as well add them now..right?

How we lookin' ?

MikeL_2

One of my favorite subjects & discussions is dwv system piping.

I propose a single 1.5" waste arm could serve both lavs as long as they're within 6' of the stack vent.

The arm would connect to the stack with a ty; a vertical wye with a 45 here could cause the vent to be flooded.

The first lav would need a horizontal wye & 45.

This works as a combination waste & vent, not a wet vent because the 1.5" arm is a pipe size bigger than the lavs 1.25" drain....…

Lance

Its all in the code. Follow the code, pass the inspection. This is the reason masters have to learn their trade. Get the illustrated national code book and its all there. You may think logic and reason works, but its all physics. The vent opening above the roof in freezing areas has to be large enough to prevent frost closure. They used to be small until nature told them how to it must be to work right. Just one example to not ignore the codes. By the way, people do die when plumbers fail to do it right. Especially with cross connections. But isn't that true in all trades? Many do not appreciate good craftsman who save lives by preventing hazards.

Intplm.

Looks better.

"The waste dump" .Are you referring to the fitting that transitions from horizontal to vertical in aqua? If so then that fitting should be a tee-wye.

If this is going to be a vanity lav set up, then you can expose the clean out plug through the wall there. If it is a pedestal lavatory not so much, unless you redirect the plug to an accessible area, and maybe decoratively through the wall, and then make it readily accessible in the wall.

DCContrarian

https://forum.heatinghelp.com/discussion/comment/1835599#Comment_1835599

This would be my vote as well. Much simpler. From the picture it looks like the far sink is less than three stud bays from the stack, well within reach of a 1-1/2" trap arm.

DCContrarian

And I don't see any point in the clean outs, just use a trap that comes apart and go in there if you need to.

Javelin

Thank you again.. a couple of points of clarity…

1. the 1.5" vent there will go up into a soffit in the ceiling, turn 90, then go about 9 ft until it ties into another 1.5" (from the shower), then up to the attic where they tie into a 4" main vent. Not sure if that matters to this discussion.
2. So I still seem confused on which fitting to dump the 2" horizontal into the 2" vertical.. please see the fitting highlighted in orange… Then reference the 3 "floating" fittings in the foreground… 1, 2, 3.. .which should I use?
3. And not knowing any better, I sort of agree with the clean out comment from @DCContrarian maybe? I don't think I will easily be able to get to them, and can always "slip out" the trap under each sink if really needed right?

hot_rod

can you get below to come up between the two lavs?

Is the vertical pipe you show venting a fixture below? If so you cannot dump into it.

A CO is required to be the full size of the piping. If the sinks have 1-1/4" traps, they do not serve as a CO, technically speaking.

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