Regular 90 elbow/sanitary tee vs long

[sonnaps]

I've been struggling with finding info on this, it's such a basic question I'm sure.

I'm setting up a double lav and am basically following the example in the pic attached. I'm not sure if that elbow on the right should be a normal 90 elbow or a long sweep 90. And if so, then shouldn't the tees have the same kind of long sweep? I couldn't seem to find a "Long Sweep Sanitary Tee" in the local big box store, just a "Combination Wye & 1/8". Are those the same thing? They look the same so I don't know if I'm just getting terminology wrong. I thought wyes had a sharper angle inside or something.

I edited that pic with what my setup will be and marked the areas in question. Right now my setup is pretty much exactly like the pic with standard sanitary tees and 90 elbows.

Will those long seeps choke the vent air like in that third pic? I just want to know what will pass inspection basically.

 

[Reach4]

The fitting on the far left in the wall must be a sanitary tee if vented from above the tee. I am not a plumber.

The vent is after the trap.

I would think you would use slip fittings. They are easier.

What is your bowl center to bowl center distance? Where is your sanitary tee-- off to tle left as in your example photos? I think there may be some maximums here.

 

[Sponsor]

 

[hj]

You do realize that your photos show a double kitchen sink, NOT a double lavatory, don't you? Two completely different "animals".

 

[Reach4]

Double lavatory bowls can share a p-trap if they meet the 30 inch rule, right?

 

[sonnaps]

You do realize that your photos show a double kitchen sink, NOT a double lavatory, don't you? Two completely different "animals".

Yup, I know. The outlet for the drain coming out of the wall for the p-trap is off to one side close to where one lav would be, so this was the best real-world example I could find.

 

[sonnaps]

Double lavatory bowls can share a p-trap if they meet the 30 inch rule, right?

This is what I found in my research too. The drains for the two sinks are just about exactly 30" apart.

 

[sonnaps]

Ok, how about this setup instead? It's a screenshot from a YouTube video by This Old house. Here is the link to the video:

The other sink is way off to the right. I'm sure you guys know what you're looking at. If I can follow it, I'm sure you guys can. Starting from the drain outlet, it looks like a 45 to a wye - then on one branch is a couple more 45's, a short section of pipe, then a 90. That shoots off across to the other sink.

Using this setup it seems I am able to have two p-traps sharing the one vent in the wall. Is that right? This way if the two sinks really are more than 30" apart, I can do it this way.

THE WRONG WAY

 

[Reach4]

The other sink is way off to the right. I'm sure you guys know what you're looking at. If I can follow it, I'm sure you guys can. Starting from the drain outlet, it looks like a 45 to a wye - then on one branch is a couple more 45's, a short section of pipe, then a 90. That shoots off across to the other sink.

Using this setup it seems I am able to have two p-traps sharing the one vent in the wall. Is that right? This way if the two sinks really are more than 30" apart, I can do it this way.

It looks bad to me.

I did not see the P-trap on the right sink, but I will assume it is there. I did not go back and inspect carefully. The trap arm from the right comes across and then goes down to join the trap arm from the left sink. You cannot go down until it is vented. There may be other things wrong, but that is what strikes me.

 

[Terry]

The video is a hack that doesn't work. It's a handyman's idea of something that no plumber would do. No plumbing inspector would okay that work.
That is designed to siphon the trap on the right. Who is this handy hack installing and making video's?
Please don't listen to this guy.

This is a good read that I recommend.
Helpful Plumbing Hints for Residential Construction by Bert Polk Plumbing Inspector Lincoln County

 

[sonnaps]

Lol, that is exactly why I am posting here asking questions. I would assume that a This Old House video would be doing it the right way, but I trust the real pros way more than a random YouTube video. So how would you guys do it?

I have a wall that I cannot drill any holes horizontally at all. There are two drains going down, one for the washer and one for the two sinks. There is one 2" drain going down with a 1-1/2" vent going up, and a 2" outlet coming out of the wall. This is for the two lavs. Whatever I do has to stay out of the wall under the sink(s) area.

I want to do it the right way, for my own sake and it will be inspected as well. I'm attaching two pics of the actual location. The first is looking at this wall from the front on the laundry room side. The second pic is looking at the same wall from in the master bathroom.

I had to squeeze a lot in this one wall without messing with structure as best I can. The washing machine will drain and vent separate from the double lav on the other side. This is the best I could figure out with the area I had to work with. Please be kind.

There's also a floor drain in the floor there in the laundry that you can't see in that pic. That is going to join up with the 2" pipe for the double lav as well. I have a special trap on order with a top clean out as well as a trap primer port. I plan on hooking up that primer to the water line for the washer or possibly one of the sinks.

Edit: a link to full size images so it's easier to make everything out: https://imgur.com/a/sLSKH

 

[sonnaps]

Anyone have any pro suggestions on how he or she would do it with what space I have to work with?

 

[MKS]

Not a pro.
It looks to me there will be a lav on each side of the vertical drain that is to serve them.
In the Bert Polk file, the two lavs side by side with fixture fitting looks like it would apply. Also notice at the bottom it turns maybe 45 to go around the bottom plate. You may need something like that because the vertical drain line is not in the same plane as the fixture fitting and lines that go out from there.
Building a false wall?

 

[sonnaps]

I took a look at that file, but most if it was all done within the wall. I can't build a false wall in front because of size constraints. I wouldn't be able to fit one of those double sanitary tees in that particular spot anyway.

 

[Reach4]

I am not a pro, but these come to mind:

1. You could run one bowl to the sanitary tee. You could run insert a drain tee of some sort below that, and feed the other bowl into there, with an AAV venting the trap arm.
2. I think you could wye out from the santee and go to both trap arms. Each trap arm would be vented by its own AAV.

I am not sure these would be OK, but I would think so.

 

[MKS]

In the diagram Reach4 posted the Wye in the center drawing. Could that Wye be connected to a stub out from the vertical drain via Santee then have trap adapters attached to the two inlets to catch the arms from the individual bowls.?

 

[Reach4]

How about this:

But wait! The vent lines are between two close studs, and going through the studs is not going to work. How about bringing the double fixture fitting out of the wall a few inches into the vanity cabinet. Connect to the drain and vent lines with fittings at 45 degrees, which is considered vertical.

 

[sonnaps]

I really thought of doing that, but I wasn't sure if the inspector would like laugh at me and say that won't fly at all. I don't care myself, it's under the vanity cabinets.... as long as it's legal to do.

So 45's are still considered vertical? That's good to know. I appreciate your help.

I wonder if there are any other options?

 

[MKS]

Thanks Reach4, this is what I was thinking.