Double Sanitary to Double Wye, inlet position is before wye

[thekingofspain]

I am doing a a remodel and replacing double sanitary fitting that has inlet hub at the end the fitting, between the two sanitary branches. The only double wye fitting with an inlet that I can find has the inlet at the front of the fitting, before the double wye, not after it. Besides the existing vent pipe now being in the wrong position, does the placment of where the inlet is relative to where the branch occurs on the fitting matter for venting jack n jill toliets?

 

[John Gayewski]

You need a double fixture fitting.

 

[Sponsor]

 

[Jeff H Young]

Venting back to back toilets off the same vertcle stack ,a double fixture fitting, double wye , or even a double combi can be used. a double santee no good for this.

 

[wwhitney]

I am doing a a remodel and replacing double sanitary fitting that has inlet hub at the end the fitting, between the two sanitary branches. The only double wye fitting with an inlet that I can find has the inlet at the front of the fitting, before the double wye, not after it. Besides the existing vent pipe now being in the wrong position, does the placment of where the inlet is relative to where the branch occurs on the fitting matter for venting jack n jill toliets?

You seem to be speaking of a 5 connection fitting. And by referring to the side inlet as the vent, I take it the barrel is horizontal. It is unlikely in new work that any such fitting would be appropriate to use with the barrel horizontal.

You really need to provide more context to allow us to advise you on the correct fitting choice. A floor plan of both bathrooms with all the DWV drawn in would be a good starting point.

Cheers, Wayne

 

[thekingofspain]

Exising fitting double sanitary fitting to be replaced: Double Sanitary Tee with 90° Inlet Hub - PVC DWV
Proposed replacement fitting: Double Wye with inlet

 

[wwhitney]

OK, Chicago has its own plumbing code that apparently doesn't permit wet venting. It does permit common venting of two fixtures.

Article 9. Vents (18-29-901 et seq.)

Legal publisher offering ordinance codification services for local governments, specializing in providing codes of ordinances in print and on the Internet

codelibrary.amlegal.com

I am inferring from that and from your diagram that (a) the green arrows are horizontal, and (b) there are 2 upstream sinks and 2 showers, all of which are individually dry vented

Then certainly the double sanitary tee with secondary side inlet was the wrong fitting originally. It's two primary branch inlets will be at best fully flat (actually level) when installed horizontally. And at worst if one side inlet is slightly lower than the other, that side inlet will have reverse slope.

The horizontal double wye is better than the double sanitary tee. I see no issue with the location of the side inlet, and given that the side inlet has no radius to it, I infer that it can only be expected to be used as a vent on that fitting. The issue with a horizontal double wye is that the side inlets have, at best (if perfectly even with each other), 70% of the slope of the barrel. So I would recommend that you slope the barrel at least 1/70% = 140% of the minimum slope for a 3" line under the Chicago code. The use of street 45s directly into each branch inlet helps to minimize the portion of the final configuration that may be at reduced slope, as you can adjust each street 45 individually.

Even better would be to use two separate wyes in series, that would allow you to adjust the slope on the inlet of each wye individually. But then you'd need to do two separate vent takeoffs on each WC fixture drain, either before the wye or by using wyes with side inlets. So that would take up a lot of space. If you don't have the room to do all that, the horizontal double wye with 40% extra pitch on the barrel is reasonable solution.

Cheers, Wayne

 

[Reach4]

1. I presume your drawings are top (plan) views.
2. Are you in Chicago city limits?

 

[thekingofspain]

1. I presume your drawings are top (plan) views.

Yes for top view, updated the diagram with a side view and added toilets to over head view.

Note diagram is pretty much to scale, there is not allot of space between fittings. The proposed plumbing with a double wye budded up to the main stack vent, the toliet branches extend past their existing drain pipes by around a 1/2 inch.

2. Are you in Chicago city limits?

Not in Chicago limits, suburbia on Chicago water.

This is probaly a silly question, but is a vented double wye even needed if main vent pipe is like 3 inches further down the line the double wye vent?

 

[wwhitney]

Not in Chicago limits, suburbia on Chicago water.

You should clarify whether you are subject to the Chicago Plumbing Code, or the Illinois State Plumbing Code. The latter apparently allows some wet venting.

§890.1500. Installation of Wet Venting, SUBPARTK. VENTS AND VENTING, PART890. ILLINOIS PLUMBING CODE, TITLE77. PUBLIC HEALTH, Illinois Administrative Code

The compilation of all agency rules is known as the Illinois Administrative Code. The Code, which is larger than the Illinois Compiled Statutes, is maintained electronically by JCAR/LIS. And it is updated weekly by the Illinois General Assembly.

ilrules.elaws.us

This is probaly a silly question, but is a vented double wye even needed if main vent pipe is like 3 inches further down the line the double wye vent?

If you're subject to the Illinois State Plumbing Code, then maybe it's not needed. I'd have to reread the above section. It's possible that with two back to back bathrooms and with the common drain leaving the area horizontally, rather than vertically, you still need to dry vent the double wye.

Cheers, Wayne

 

[Reach4]

Outside of Chicago limits should be Illinois code, which, as you have pointed out, is much more tolerant.

 

[Jeff H Young]

I never seen these fittings used that I can remember and certainly not horizontal but a whole differant world in Illinois or Chicago I guess. you must be in a jam trying to repipe an old house?

 

[thekingofspain]

I am inferring from that and from your diagram that (a) the green arrows are horizontal, and (b) there are 2 upstream sinks and 2 showers, all of which are individually dry vented

Yes two small bathrooms, mirror opposites of each other, jack sink to jill shower, shared toliet, jack shower to jill sink. Trying to update jack and leave jill alone. The original jack bathroom (even bathtub) is not level and drops 2 inches over 6 feet. I thought the house shifted but now i think it was built this way. The 5" tiling is level and while lifting and leveling the tube 2 inches, I found the dated receipt for the 5" tile under the tub that matches the build year.

 

[thekingofspain]

Main issue with the existing plumbing is the the new toliets have too much pressure and initially flush into the other toliet (straight) vs down the waste pipe (90 deg turn). With jack toilets removed and a temporary stand pipe inserted in its placing, flushing jills toilet shoots water on average about 4 inches above flange.

 

[thekingofspain]

I never seen these fittings used that I can remember and certainly not horizontal but a whole differant world in Illinois or Chicago I guess. you must be in a jam trying to repipe an old house?

I have not bought the double wye with inlet yet. Only spears manufacturs it now, I have one other reference to another manufactuer, but that company does not every have the part in their catalog. I obtained a 3" double wye for $14 shipped from Home Depot (thank you for ever entered in the 2" price for the 3" part equivilent). Best online non fake site for the double wye with an inlet is a $135. Found a premade fitting that seems be Chicago code compliant, 3 DWV Double Combination Wye + 1/8 Bend ALL HUB, $731.01 USD. Thinking most of these 5 way fittings where a thing in the 70s and then became obsolute via changes in the plumbing codes and or toliet changes.

 

[Jeff H Young]

They were never very common out west to my knowledge . the house was plastic plumbing ? ABS or PVC . I understand your in a jam but Id never actually want to build with those some old ways arent good ways my opinion. Sweeping directional fittings seem to make more sence

 

[thekingofspain]

I have read the IL codes a few times:

d. A horizontal wet vent may be used for two fixtures set on the same floor level with one fixture connecting upstream of the other fixture on the horizontal line, provided that the horizontal wet vent/drain between the two fixtures is one pipe diameter larger that the upstream fixture trap. The vent connection shall be located between the traps, and each trap-to-vent distance shall be in accordance with Appendix A.Table I. (See Appendix K.Illustration Q.)

e. A vertical/horizontal wet vent may be used for two fixtures set on the same floor level with one fixture connecting to the vertical stack and one fixture connecting to the horizontal line, provided that the wet vent/drain is one pipe diameter larger than the upper fixture trap and the drains conform to Appendix A.Table I. (See Appendix K.Illustration R.)

g. Bathroom groups installed back-to-back consisting of two water closets, two lavatories, and two bathtubs, showers or floor drains may be installed without individual vents, provided that:

1. The water closets are wasted to a proper vertical drainage fitting;
2. The bathtubs, showers or floor drains connect to the stack at the same level as the water closets;
3. The lavatories connect to the stack at the same level; and
4. The vent is a minimum of 2 inches in diameter. (See Appendix K.Illustration T.)

What is a proper vertical drainage fitting as refererred to in g.1?

 

[wwhitney]

What does Appendix K Illustration T show?

Cheers, Wayne

 

[thekingofspain]

Uploaded Appendix K diagrams Q, R & T

 

[wwhitney]

Well, that certainly sounds and looks like the IL code only allows vertical wet venting on a double bathroom, not horizontal wet venting. Which would mean that you should maintain the dry vent arrangement you currently have, and use the double wye with side inlet.

Cheers, Wayne

 

[thekingofspain]

Well, that certainly sounds and looks like the IL code only allows vertical wet venting on a double bathroom, not horizontal wet venting. Which would mean that you should maintain the dry vent arrangement you currently have, and use the double wye with side inlet.

Cheers, Wayne

Thank you, looks like I need to buy that $150 fitting then and move the toliet cold water supply inlet value/hammer as that is where I calculate where the new dry vent will be. I guess is a better solution that putting in a new dry vent after the double wye (which would probably not be to code any way), which would require more dvw upsteam changes in addition to moving the hot water supply hammer.

It just seems silly require a vented fixture when butted to another vented fixture that has excess capacity. The proposed new vent will have less than a 4 inches (vs the existing 9.6 inches) from the main vent, but it is what it is.