Double fixture tee or double sanitary tee?

[hj]

fitting

If a double Y with 1/8 bends were acceptable there would be little need to manufacture a double fixture fitting. But since it would create 3/4 "S" traps and possibly not fit in the space available it is even less acceptable than a sanitary cross.

 

[Basement_Lurker]

But is a double fixture fitting really the best fitting for a back to back toilet installation? Would using a double wye really put either of the toilets at risk of self-siphoning?

I currently use a double fixture fitting in this application, but I somehow think using a double wye would be better.

 

[Sponsor]

 

[jdgoodman]

You would not be able to use a double wye on a back to back setup because the weir of your trap would be higher than you vent take off. UPC accepts san crosses if the barrel is 2 pipe sizes larger than your branches.

 

[hj]

toilets

Our inspectors will not approve an double Y for that type of installation, even though it does not affect the operation of toilets like it would sinks. We always use a back to back fitting.

 

[Vinnie J]

I am trying to figure out if my situation applys here. I have a shower drain and a kitchen sink i am trying to drain and vent. because of the angle of the horazontal waste line in the basement beneath the shower, i would like to 90 bend up, with a double Tee on top of that, right branch going strait to the 2" shower p-trap, left branch going to pick up the kitchen sink (the sink is re-vented above the high water level of the fixture, the shower is not), the top of the double Tee, being the vent, goes up through the floor, between the shower and the sink (in the back of a closet) and then has a clean out wye accessable.

I want to use a double Tee because the space is so tight (the sink and the shower drains are about 4 feet apart). I already called my inspector and asked about useing a double san-tee, he said no go, unless the shower was somehow re-vented also. I am now wondering if a double fixture fitting would be alright in this situation. If it is not (or even if it is) then could some one please help me understand in what situations these three fittings are to be used? BTW I am in minneapolis so the inspector is very thorough.

PS. My name is Jampel, and thank you to Terry and all the people on this site, i have read and benifited from many threads here but this is my first post.

 

[Terry]

Jampel,
The sink and the shower trap are not close enough to work on a fixture cross together.
The shower trap is below the floor and the sink needs to be above the floor.
That means the shower would need it's own vent, that can be "revented" at 42" above the floor with the kitchen vent.
Instead of a fixture cross, you would have a santee pointing out for the shower, vent and then p-trap.
Above that on the next floor, santee pointing toward sink, with the vent out of the top that then revents at 42" to the shower vent.

 

[Cole T.]

I hate to bring up an old thread but wanted to get some advice from individuals that have a bit more experience than I do. A little back story on myself I am an electrical engineer and currently am remodeling my entire house. Did the electrical and plumbing myself with advice I've read from here, reading the IPC and other code references. I also have a neighbor that is a retired master plumber that has given me some guidance.

So I have an issue related to this thread and trying to get some recommendations on how to approach this. I have two double vanities that I plumbed with the Spears P500-241 (2" x 1-1/2" x 1-1/2" x 1-1/2" PVC DWV Double Fixture Fitting). Well I had the 2nd rough inspection today and the inspector did not pass my inspection because he stated these were double combo fittings and are not permitted. He wants me to remove both fittings and install double sanitary tees. From everything I have read here and other sources in fact looking at the spears catalog it shows this is NOT a double combo wye. Am I mistaken and this is not a double fixture? I am thinking about speaking of the inspector, talk with him more on this, and even getting all three fittings to show him the difference. Just would rather not piss in his Wheaties before the next inspection. Any suggestions or even references that I could show him?

* Attached picture is the fitting I used in both locations.

 

[WorthFlorida]

This is the difference, look at the center line. It cannot be continuous. This has come up alot and after years of looking things up I found one site that explained it. I'm not a plumber but I'm sure I'm right on it. The inspector has a sharp eye. You may ordered the right part but was shipped the wrong one. To the untrained eye most would not know the difference.

 

[WorthFlorida]

 

[Cole T.]

View attachment 57621

My picture is not completely level. In the two pictures you posted the line is slightly higher in the abs double fixture than placed with mine. His is also a 2x which has all 2" hubs while mine is a 2 x 1 1/2 x 1 1/2 x 1 1/2 where the bottom hub is 2" and all others are 1 1/2") In fact the fitting also has a stamp of P500-241 and comparing it side by side with a combo wye is quite different.

I'll take a better picture and closer to the fitting tomorrow, but here is a double san-tee(p429-251), double fixture(what I have/p500-241), and double combo wye(p507-015) respectively. The double wye would not be allowed nor should it due to it creating a s-trap. but the double san-tee and fixture that I have would allow the vent air to pass which is what you want.

 

[Cole T.]

So the green line in these attached pics is the vent while the red is the weir. If the weir is above the vent it will create a s-trap so you need to have the vent above the weir from what I am understanding from this forum and other sites.

 

[Cole T.]

View attachment 57621

here is a better picture and a close up of the model stamped on both sides of each fitting(both are the same). Any professional opinions? If I am wrong about it being a double fixture and need to change it to a san-tee like the inspector wants. Wouldn't be the first time i've been wrong ask my wife haha.

 

[Reach4]

Cole T.:

See page 541 of http://www.spearsmfg.com/super_sourcebook/SSB-1 Part 1 List Price Catalog/078 PVC DWV Drain Waste Vent Fittings.pdf

 

[Cole T.]

Well went into talk to the inspector and he took today off so the supervisor came out. He told me that they will not accept anything other than a san-tee. He told me that the double fixture is for two toilets back to back and it will block up if flooded with water. Asked him why would they make double fixtures in this size and he replied, " that I can use them for sinks back to back but not for a double vanity..."

 

[Reach4]

Well went into talk to the inspector and he took today off so the supervisor came out. He told me that they will not accept anything other than a san-tee. He told me that the double fixture is for two toilets back to back and it will block up if flooded with water. Asked him why would they make double fixtures in this size and he replied, " that I can use them for sinks back to back but not for a double vanity..."

There you have it. The "authority having jurisdiction" can override the code (IPC in your case).

Since the main advantage of the double fixture fitting is for rodding, you might add a cleanout just above the new double santee. If the drain is 2 inch and the vent is 1.5, I don't know if that cleanout should be 1.5 or 2.

 

[Mliu]

Asked him why would they make double fixtures in this size and he replied, " that I can use them for sinks back to back but not for a double vanity..."

This makes no sense: water doesn't know the difference between two sinks back-to-back or side-by-side. It sounds like he doesn't really know so he's just making stuff up on the fly.

 

[Reach4]

This makes no sense: water doesn't know the difference between two sinks back-to-back or side-by-side. It sounds like he doesn't really know so he's just making stuff up on the fly.

Let's presume you are right (I do). What should Cole do? I say cave in without fighting the ignorance. After all, this is a one time event for Cole. Maybe name and shame after he gets his final approval.

 

[Mliu]

Personally, I think inspectors should be challenged and corrected when they don't know the code and start BSing people. But I also understand that this can be an uphill battle and inspectors have the power to screw you if you need additional inspections.

It's up to Cole to decide what he wants to do.

 

[Mliu]

The "authority having jurisdiction" can override the code (IPC in your case).

Let me add that I believe that local jurisdictions can override code by publishing their own set of standards (as is done in many states and cities). I do not believe that individual inspectors have the mandate or authority to make up their own rules.

 

[Reach4]

The IPC writers could have helped by mentioning double fixture fittings.
TABLE 706.3 FITTINGS FOR CHANGE IN DIRECTION mentions sanitary tees and has a note that mentions double sanitary tees, implying they were permitted except in certain circumstances. I was looking at the 2009 IPC.

I do not believe that individual inspectors have the mandate or authority to make up their own rules.

What is making up rules vs what is interpreting can be unclear.