I Need to Vent

[Thomas K]

Thank you again, Wayne! I drew a schematic of what you were describing, and think I have it, but drawing would not upload. I took a photo of schematic and uploaded it here.

Fitting should be (starting at farther sink):

Long turn 90 degree ell turned flat, poking out of wall for second trap pipe-pipe- upright combination tee wye + 1/8 (bend turned toward ceiling)-pipe- combination tee wye + 1/8 (curved side inlet poking out of wall for first trap) pipe-existing cast iron san-tee.

I'm not sure if you were talking about combination tee wye + 1/8 fittings, but I think so. They look just like sanitary tees, but have a longer curve. I am also not sure a combination tee and a combination tee wye are different parts.

I don't know why inspector told me I couldn't use one drain pipe with air vent; I posted question about IPC 911 and never got an answer either. (shrugs.)

I guess the Keep It Simple Stupid principle really does apply to me here.

 

[wwhitney]

I'm not sure if you were talking about combination tee wye + 1/8 fittings, but I think so.

Yes, and your recapitulation sounds good.

They look just like sanitary tees, but have a longer curve. I am also not sure a combination tee and a combination tee wye are different parts.

Different names for the same part.

A combo is like a san-tee in that the relative orientations of the 3 connections are the same. But they have different sweeps (radii of curvature). A san-tee matches a medium bend, and in drains both are only allowed for a horizontal drain turning vertical (downwards). A combo (or literally a wye fitting plus a street 45, hence the name combo) matches a long turn bend, and in drains the additional sweep is required for horizontal to horizontal or vertical to horizontal transitions.

Cheers, Wayne

 

[Sponsor]

 

[Thomas K]

Thomas, Wayne commented on minor fix to make double vanity code compliant. Im not so familiar with IPC but sounds good to me. also yougot so much going on here its a bit confusing . more pics that show what your talking about please. Are you clear on the double lavs on how your fixing it ?

Jeff: I will be using Wayne's suggestions to repair the current way it is plumbed, adding the correct fittings and a vent pipe between the traps on drain pipe. I will be posting photos here of work completed as I finish it. I may just rough it in and take photos of that before gluing it.

 

[Thomas K]

Yes, and your recapitulation sounds good.


Different names for the same part.

A combo is like a san-tee in that the relative orientations of the 3 connections are the same. But they have different sweeps (radii of curvature). A san-tee matches a medium bend, and in drains both are only allowed for a horizontal drain turning vertical (downwards). A combo (or literally a wye fitting plus a street 45, hence the name combo) matches a long turn bend, and in drains the additional sweep is required for horizontal to horizontal or vertical to horizontal transitions.

Cheers, Wayne

Wayne: I am not trying to be a comedian here, nor sarcastic. I'm just trying to guess, though. Are you a plumber, or an engineer?

 

[wwhitney]

I'm a mathematician turned full-time amateur owner-builder doing all the trades.

As for dry fitting, be careful that often you can't fully seat PVC pipe in a hub dry. So if you get the spatial arrangement the way you want it with a dry fit, you may have to cut ~ 1/4" longer pieces for each pipe segment to properly glue it up.

If you want to check the relative arrangement of the fittings, you can just lay them out on the floor in order in the proposed orientations and take a photo for our feedback. How is the PVC connected to the cast iron?

Cheers, Wayne

 

[Thomas K]

I'm a mathematician turned full-time amateur owner-builder doing all the trades.

As for dry fitting, be careful that often you can't fully seat PVC pipe in a hub dry. So if you get the spatial arrangement the way you want it with a dry fit, you may have to cut ~ 1/4" longer pieces for each pipe segment to properly glue it up.

If you want to check the relative arrangement of the fittings, you can just lay them out on the floor in order in the proposed orientations and take a photo for our feedback. How is the PVC connected to the cast iron?

Cheers, Wayne

Well, you certainly know your plumbing components.

PVC is connected to cast iron with threaded coupler as shown in attached photo. I also attached photo of what I think you were talking about, the 90 degree long ell fitting and the combo tee wyes. This is one from Home Depot; I know I should probably get them from plumbing supply store, but this may work. Only it doesn't say 1/8 on description. It says 1 1/2" PVC DWV long radius combo tee wye. I think it's the same, but am not sure.

 

[wwhitney]

The parts look good, the combo is definitely correct, it's just a little harder to tell on the elbows from a picture. There are 3 different styles of plastic elbow: vent (where the hubs actually touch, only allowed for venting, and more expensive, so only worth using if you really need the space), medium turn, and long turn. You want the long turn, it will be the longest for a given size.

You'll need pipe dope or teflon tape on the threaded connection. For DWV, I've had better luck with a plastic-compatible pipe dope than with teflon tape.

Cheers, Wayne

 

[Thomas K]

The parts look good, the combo is definitely correct, it's just a little harder to tell on the elbows from a picture. There are 3 different styles of plastic elbow: vent (where the hubs actually touch, only allowed for venting, and more expensive, so only worth using if you really need the space), medium turn, and long turn. You want the long turn, it will be the longest for a given size.

You'll need pipe dope or teflon tape on the threaded connection. For DWV, I've had better luck with a plastic-compatible pipe dope than with teflon tape.

Cheers, Wayne

It is listed as hub by hub long turn 90 degree elbow fitting. And yes, I can lay parts out on floor in configuration and photograph.

 

[Jeff H Young]

fittings look good. As for buying a fitting from home depot or the plumbing supplier some stuff matters some dosent. I wish I could never buy from a big box but when its half the distance and half the price I dont feel so bad. getting the supplys you need at a good price and not having to chase down parts in stock can be a challenge

 

[Thomas K]

Just asking here, before buying parts. Should any of these pipes be 2" because this is a wet vent?

 

[Reach4]

Just asking here, before buying parts. Should any of these pipes be 2" because this is a wet vent?

I think everything in the wet vented area should be at least two inch, I think. See https://wabo.memberclicks.net/assets/pdfs/Plumbing_Venting_Brochure_2018.pdf page 12 and others.

Is https://terrylove.com/forums/index.php?attachments/img_1792-jpg.66904/ still your plan? If so, the combo should be 2" x 2" x 1-1/2" I think, with a bushing on the horizontal input.

 

[wwhitney]

Everything can be 1-1/2".

Per https://up.codes/viewer/alabama/ipc-2015/chapter/9/vents#912.3 an IPC wet vent that is only receiving the drainage of a lavatory (1 DFU) can be 1-1/2". And a horizontal 1-1/2" drain is good for 3 DFUs.

Under the UPC (not applicable here to my knowledge), the wet vent would have to be 2".

Cheers, Wayne

 

[Reach4]

Everything can be 1-1/2".

Per https://up.codes/viewer/alabama/ipc-2015/chapter/9/vents#912.3 an IPC wet vent that is only receiving the drainage of a lavatory (1 DFU) can be 1-1/2". And a horizontal 1-1/2" drain is good for 3 DFUs.

The "pipe to second trap" pipe contains only the drainage of one lavatory?

 

[wwhitney]

The "pipe to second trap" pipe contains only the drainage of one lavatory?

From left to right we have three pipe segments in the diagram you referenced. I think you're referring to the middle one, so yes. But to cover all the bases:

Left - carries the drainage of 2 lavatories (2 DFUs), is not a vent, so 1-1/2" is OK (good for 3 DFUs as drain only)
Middle - carries the drainage of 1 lavatory (1 DFU) and is a wet vent for the left hand lavatory. 1-1/2" wet vent is good for 1 DFU drainage.
Right - carries the drainage of 1 lavatory, is not a vent, so 1-1/2" is OK.

Cheers, Wayne

 

[Reach4]

Left - carries the drainage of 2 lavatories

Ahh... The first and third p-traps.

 

[wwhitney]

The "pipe to second trap" pipe contains only the drainage of one lavatory?

I see now that the diagram has the p-traps labeled first and second, so yes, there's just one lavatory on the second p-trap, as I understand it. I had forgotten that the diagram had the first/second labeling, so I wasn't sure which pipe was the "pipe to second trap".

Cheers, Wayne

 

[Thomas K]

And I've been checking my email all day to see if I received a reply. Heh, didn't check the little box included with the post that says "notify me of new posts."

 

[Thomas K]

I see now that the diagram has the p-traps labeled first and second, so yes, there's just one lavatory on the second p-trap, as I understand it. I had forgotten that the diagram had the first/second labeling, so I wasn't sure which pipe was the "pipe to second trap".

Cheers, Wayne

I hope I didn't confuse anyone. I just meant the two traps in the vanity; I wanted two traps because we bought one of those vanities that has all of the drawers in the middle and you can't run a pipe between 2 sinks with one of those. I looked up Alabama plumbing code, and it is under IPC 2015 only. Not UPC.

The two-sink setup in pictures is all that drains into 4" pipe in that spot from 1 1/2" drain pipe.

In the smaller bathroom, 2" pipe runs from the roof to a 2" x 2" x 1.5"cast iron sanitary tee. At the small sink, a 1 1/2" drain screws into said sanitary tee. 2" drain pipe continues from sanitary tee to Y-pipe under floor, where it and 2" pipe from shower trap converge. Other end of 2" Y-pipe drains into 4" cast iron.

I was also wondering if second bathroom plumbing will pass code if I just replace all of the cast iron pieces there with PVC in the exact form they are in now. I mean the Y-pipe, 2" pipe, 45 degree fittings, sanitary tee, etc., all joining a Sawzall-cut 2" cast iron nub with shielded neoprene coupling.

For now, I will lay out parts for rough in, as promised, and photograph.

Thought for the day: Only about 3% of the total number of galaxies in our Universe are presently reachable by us, even if we left today and traveled at the speed of light.

 

[wwhitney]

I was also wondering if second bathroom plumbing will pass code if I just replace all of the cast iron pieces there with PVC in the exact form they are in now. I mean the Y-pipe, 2" pipe, 45 degree fittings, sanitary tee, etc., all joining a Sawzall-cut 2" cast iron nub with shielded neoprene coupling.

Your "existing" isometric doesn't show how the sink in the second bathroom connects, but if it's a san-tee like the in the OP, then I believe the layout shown in the "existing" isometric is definitely IPC compliant from the 2" branch on the 4x4x4x2 tee upstream. [I think the 4x4x4x2 tee itself is dubious, as the 2" side inlet has no radius to it, and I can't tell if the 4x4x4 part is a proper combo or an improper san-tee on its back.]

Cheers, Wayne

 

[Thomas K]

Your "existing" isometric doesn't show how the sink in the second bathroom connects, but if it's a san-tee like the in the OP, then I believe the layout shown in the "existing" isometric is definitely IPC compliant from the 2" branch on the 4x4x4x2 tee upstream. [I think the 4x4x4x2 tee itself is dubious, as the 2" side inlet has no radius to it, and I can't tell if the 4x4x4 part is a proper combo or an improper san-tee on its back.]

Cheers, Wayne

I have a picture of that sink drain here somewhere. 2" Pipe in lower photos is the one I was talking about cutting. Are you saying if I cut into it I will be causing more problems as far as it being proper plumbing?

I even thought about having that cast iron replaced with pvc, but there is 4" stack going all the way through roof, and I don't know exactly which pieces would make it compliant. I don't know how much that would cost, but I'm betting it would be several thousand dollars.