Three questions about Bathroom DWV plumbing...

[MG70]

IPC 2018, I'll be plumbing two back to back 3 piece bathroom groups using a horizontal 3" drain and a 2" vent.

Question #1. When changing the direction of a horizontal 3" drain pipe to a vertical can I use two (90) Long sweeps, one at the top and one at the bottom, or are there better fittings for the job?

Question #2. The lower horizontal section of the 3" drain pipe, after having already dropped a few inches, and before connecting to the main soil stack may be a few inches longer than 5' and require a separate cleanout. Should I place the cleanout on the horizontal section of the pipe or in the vertical main soil stack (where there's already one that will need to be moved)? From a layman's perspective I assume a Wye with the leg positioned at 12 o'clock to be the least likely solution to cause a problem.

Question #3. Can I tie in a separate Dry Vent coming from the kitchen to the top section of the Bathroom Vent above the highest fixture (double fixture for the lavs) in order to have only one pipe through the roof? If my calculations are correct, using a 3" drain and 2" vent, and including a kitchen sink, waste disposer, and a dishwasher, it would be a total 18 DFUs which is allowed to extend up to 110'. In my case, from where the Kitchen Dry Vent starts to where it connects above the double fixture for the Lavs, it's probably 35'. I just don't know whether I can connect to the bathroom Vent or if each subgroup of fixtures needs its own vent.

I'm sorry I don't know how to write on the images, but to the Left of the Main Soil Stack is where the back to back bathroom drain is going to connect, and to the Right of the Main Soil Stack is where the Kitchen drain is connected and above it is its dry vent (disconnected). Currently no fixtures are connected to any of these pipes.

Thanks in advance for any tips and suggestions and a safe weekend for all!

 

[wwhitney]

1) Horizontal (going downstream) to Vertical (downstream) would only require one 90 degree bend. It may be a regular quarter bend and need not be a long turn. Vertical to Horizontal (again both downstream) would require a long turn 90 degree bend. If you just need to transition from one horizontal elevation to another not far below it, and still point in the same direction, you could consider a pair of 45s to turn Horizontal to 45 degrees Downward to Horizontal, if you have the horizontal room.

2) Not so knowledgeable about cleanouts, would suggest reading IPC Section 708.

3) Two dry vents may connect together at an elevation that is at least 6" above the flood rim elevation of all connected fixtures.

But a comment on your photos and description. I understand the photos to be of your basement, with both the kitchen and the bathroom on the floor above. In which case nothing in your photo would be a dry vent. A dry vent needs to be taken off at the elevation of the trap (except for a WC) or within one pipe diameter of fall from the trap outlet. And a dry vent has to rise from the takeoff vertically (which means at least 45 degrees above horizontal) until at least 6" above the fixture flood rim.

Cheers, Wayne

 

[Sponsor]

 

[MG70]

Wayne, thank you very much for the feedback and explanations!

Ref your answer to #1 above, I really liked the two 45s suggestion!

Q1. Related question, I ran across a Terry Love reply in which he mentioned a "medium 90." I have not found any "medium 90s" for sale. Is that just a "regular 90," that's neither a long turn 90 or a short "vent only" 90?

I now have a better understanding of what is a dry vent. Since the vent pipe below the kitchen does not drain water, I assumed it was a dry vent.

Q2. Can you please take a look at the attached pic that I drew and which Reach4 was kind enough to label.

Notes in reference to the diagram,
D and E will no longer be connected
A does not connect with NM
The Dash Lines --- represent the Vent from the Kitchen.

Q3. Do you know if under the 2018 IPC I can connect the vent running under the kitchen (top 2" ABS pipe) with the Vent for the Bathrooms located above G in the diagram?

Q4. I could not find a PVC double fixture fitting for use at the Lavs (G) either at Home Depot or Lowes . What's the next best option? A All Hub Double Wye + 45s , Two Wyes + 45s, or Two Combo Wye and 1/8 Bends?

Q5. I've read that it's better to connect the toilets to the drain with separate Wyes. Is that also the case with the shower bases? If a double wye and 45 or combo wye and 1/8 aren't recommended, is it ok to use 45s with the single Wyes at least with the shower bases? The shower base drains are very close to the same back wall where the 3" drain has to drop to another horizontal section and the bathrooms are only about 8' long to begin with. I'm starting to worry about the tight space even though I don't have any parts in hand.

Note, the second pic is of the dry section of the kitchen vent (top pipe) and the kitchen drain (bottom pipe) which is still connected to the soil stack.

Anyhow, that's all I can think of for now.

Thanks again and I hope everyone has a safe week!

 

[wwhitney]

1) For ABS, you just have vent 90, quarter bends, and long sweep 90s. So the quarter bend would be "medium". I think in cast iron you may have quarter bends, medium sweeps and long sweeps. And I think the cast iron medium sweep may correspond to an ABS long sweep, with the cast iron long sweep even longer. But I'm not sure about that, and it's not relevant at the moment.

2) I take it AB does not connect to NM. Looks like a fine way to wet vent two bathroom groups under the IPC.

3) I thought ABCDF is the dry vent from the kitchen on a story below, and GF is the vent for the two lavs. In which case it is fine to connect them at F as shown (assuming F is at least 6" above all the fixture flood rims, as it appears).

4) If the existing work you are tying into is all ABS, I would stick with ABS rather than switch to PVC, but either way is fine. You need a double fixture fitting, no other options are proper. E.g.

Charlotte Pipe 2 in. ABS DWV Double Fixture Fitting ABS005000600HD - The Home Depot

ABS fittings are for drain, waste and vent purposes only. They are used in gravity fed waste elimination systems and are for Non-Pressure where temperatures will not exceed 140°. ABS materials are light

www.homedepot.com

If you can't find it at a local big box, try a plumbing supply store or order it online, e.g. supplyhouse.com

5) When connecting a horizontal fixture drain to a horizontal branch, separate wyes are necessary so you can adjust the pitch of the incoming fixture drains individually. It's fine to use a wye plus a street 45, or just use a combo.

Picture) This does not appear to show anything that could be a kitchen dry vent. There's a trap on the right, which can only be for a fixture on this story, so it can't be for a kitchen on the story above, and look to be too high for a kitchen on this story. That trap is vented via the pipe that comes off just after the cleanout and rises up and then goes to the left. So it looks more like a trap for a basement laundry stand pipe or something similar.

Cheers, Wayne

 

[MG70]

Sorry for the delayed response...work got in the way!

Unfortunately, I have decided to switch the new plumbing to PVC and tie into the ABS soil stack and what I will call dry section of the kitchen vent with Oatey green transition cement. The reason being, I could not find any solid core ABS pipe, and I believe one fitting, around here. After changing the shopping list to PVC it seems it's also cheaper than ABS.

Thanks for confirming info in numbers 1-4 above! My intuition was right about the "regular 90" being a medium 90. I'll have to find that 2" PVC double fixture fitting and return the wyes and 45s I had bought. I'm about 20 miles from the closest city big enough to have a Walmart and Home Depot and Lowes and lucky that Home Depot delivers smaller items to me free of charge with no minimum purchase required. I still have to pick up large items like 2X4s and pipes and stuff.

Ref. Picture with 2" ABS pipes with the cool-looking connections. The kitchen sink P-trap (there was no dishwasher) on the floor above drained into the 2" pipe that runs above that little basement window. That lower, capped, pipe trap on the left corner of the window was from an old clothes washer that I removed. The upper 2" pipe that runs to the left had no liquids draining into it and originally tied, via a wye, into a 3" vertical ABS pipe that served as the vent stack for a 3 fixture bathroom and the kitchen sink. According to my 2018 IPC calculations I'm allowed to run 110ft of 2" vent pipe with a 3" drain, so the code they used in '75 must've been different. I just wasn't sure I could tie both vents together until your reply above...and I'm very happy that it's allowed because it means it should work.

Question #1. In Ref. to #5, above. Are all DWV combos a wye and 1/8 bend?

Question #2. In your opinion, what is the most trouble free, durable, roof vent cap to use on a roof with asphalt shingles? There has to be a provision for screens to keep birds out and we do get a little snow here usually 3-5 times per year. Please let me know if the same design vent cap can also the be used for the bathroom exhaust vents as I'll have to plan for those too. I have extra shingles from a recent roof replacement.

Thanks again for your assistance and I hope you have a good evening!

 

[Reach4]

Question #1. In Ref. to #5, above. Are all DWV combos a wye and 1/8 bend?

Are you asking if they are all cast as two pieces, and glued together during manufacture? Then no.

Or are you asking if there are unusual things called combos, such as being equivalent to a wye plus a 22. 5? Not that I know of.

 

[MG70]

Are you asking if they are all cast as two pieces, and glued together during manufacture? Then no.

Or are you asking if there are unusual things called combos, such as being equivalent to a wye plus a 22. 5? Not that I know of.

Basically, your second question, which you've answered. I just wanted to know if when someone says "you can use a combo" if that always meant a single fitting which is a combination of a wye and a 1/8 (45 degree) bend?

Thank you for your help and have a good evening!

 

[Jeff H Young]

combo or combination wye 1/8bend is a type of fitting how ever it can be made with 2 fittings sometimes using 2 fittings
there are times when using 2 fittings makes your installation easier and sometimes when the combo saves time and joints and is preferable whatever you think is easier and faster no real disadvantages otherwise

 

[MG70]

combo or combination wye 1/8bend is a type of fitting how ever it can be made with 2 fittings sometimes using 2 fittings
there are times when using 2 fittings makes your installation easier and sometimes when the combo saves time and joints and is preferable whatever you think is easier and faster no real disadvantages otherwise

Thank you. I'd bought the wyes and 45s but I'll also buy the combos, see what works best and return what I don't use. I'm not that familiar with the area's plumbing supply stores but I did find the pvc double fixture fitting at supplyhouse.com linked above.

Referring to my diagram above, I've decided to use 2" between H which is the drain/wet vent for the Lavs (via combo wye and 1/8 with cleanout) and J (main drain pipe upstream of toilets) and was wondering if there's a better transition from 2" to 3" out of the following fittings, a 2" to 3" pipe increaser reducer (a hub to hub), or a 3" to 2" spigot hub flush bushing (that looks like a donut)?

Thank you all for the help and I hope everyone has a safe week!

Now, if I could only find more time to work on this project!