Double-Bathroom Renovation, Please Critique!

[zanman]

Hi All, I'm back for the next phase of our whole-house remodel (we bought a "fixer-upper" )
I would love some feedback on my drain plan before I install this weekend, please don't hold back if something looks "wrong".
For now I am just trying to get the drain piping in so I can close-up the floor, so please disregard the lack of sink venting.

Key Points:
- Per IPC Table 909.1 don't believe venting is required for each of the 3" toilets since they are <12ft developed length from main-stack, In my case the longest is ~45"
- Same for 2" shower (~34" in my case)
- Same or 1.5" shower/tub ( ~36" in my case)
- Am I using Wyes correctly to branch into the horizontal main?
- Is that low-heel elbow an acceptable way to to divert the main stack downwards and also allow for 2" connection to sinks above?
- (similarly) Is that double-elbow (2"x1.5"x1.5" an acceptable way to branch out to multiple sinks?
- Lastly, is my toilet- junction (3"x3"x1.5" wye an acceptable way to connect a sink to a 3" toilet line?)

Thanks for all the help you guys have provided on our renovation so far, looking forward to seeing what you have to say this time around.

 

[Nick Bosco]

Wow! Love your rendering. What did you use?

 

[Sponsor]

 

[zanman]

Wow! Love your rendering. What did you use?

Its a 3D solid modelling program called Siemens NX, its a very expensive software but I have access to it through work.
Waaaay overkill for something like this but its what I use daily and am comfortable with. If you are looking for something similar but free check out Onshape: https://www.onshape.com/products/free

Also you can download 3D models of all fittings directly from Nibco: http://catalog.nibco.com/category/abs-dwv-fittings

 

[zanman]

Bumping for visibility. Would really like to see if you guys can poke any holes in the layout before I install.
Thanks!

 

[Tuttles Revenge]

The venting wouldn't pass UPC, but if IPC lets that go, I don't see any flaws with the general flow. Toilets don't really need vents anyhow. I lived in a house that didn't have any venting from the basement and main floor except where it hit the stack and nobody died.

 

[zanman]

The venting wouldn't pass UPC, but if IPC lets that go, I don't see any flaws with the general flow. Toilets don't really need vents anyhow. I lived in a house that didn't have any venting from the basement and main floor except where it hit the stack and nobody died.

This is the table I was using to determine trap-to-vent distance. Or are you saying venting through the main stack in general is not allowed?
https://up.codes/s/distance-of-trap-from-vent

 

[Tuttles Revenge]

Im saying that I work in jurisdictions that utilize the UPC code.. I've never looked at the IPC.

In the UPC how you have the drain of the sink for the most downstream toilet would be how we would vent the toilet, but with a 2". the same configuration would vent the shower drain. The vents all have to be on the Invert of the trap arm they're venting. Each trap is required to have its own vent until they combine no less than 6" above the flood level of the fixtures.

exception would be horizontal wet venting, but they've limited that to single bathroom units.

I don't know how to upload photos to draw a diagram so explaining only gets me so far.

 

[DIYorBust]

The venting wouldn't pass UPC, but if IPC lets that go, I don't see any flaws with the general flow. Toilets don't really need vents anyhow. I lived in a house that didn't have any venting from the basement and main floor except where it hit the stack and nobody died.

But didn't the traps constantly suck dry and expose you to deadly sewer gas?

 

[Tuttles Revenge]

DIYorBust... no.

 

[zanman]

Gotcha, well I guess I will look at adding a vent to the toilets then just to be safe. The standalone toilet (on the left) shouldnt be an issue to either vent through the wall (or worst case the floor). However, the toilet with the sink attached to it will be more difficult to increase to 2", since there is a rim-board underneath the wall that covers 1/2" of the bottom stud-plate.
I might just add another 1/2" wye and send a separate vent up the side, the reconnect with the existing 1.5" sink vent
Per IPC 709.1 Toilet (3 dfu) + Lavatory (1 dfu) = 4Total DFU, so that should be fine to vent both the toilet and sink on a sink 1.5? (IPC table 906.1)
Idk, somehow that doesnt seem right to me.

 

[Tuttles Revenge]

In the UPC toilets require a 2" minimum vent no matter what. Despite the decreases in volume since the code was adopted using 5gpf toilets.

Your system would work a lot like a circuit vent if none of the branches came off the top of the main drain and instead branched off horizontally. In this manner, the top 1/3 of the main drain is the vent. But I'm speaking in a practical manner, and not of a code/legal manner.

 

[zanman]

My municipality accepts IPC 2018.
Given this, I believe my original configuration is compliant based on Section 912:
All the sinks are vented individually and connect downstream from the "wet vent".
2x toilet (3DFU each), 1 shower (5.7-12.3gpm, 3 DFU), and 1 bath (2DFU) = 11DFU total, so I believe my 3" horizontal is sufficient to serve as a wet-vent

@Tuttles Revenge , i think I will take your suggestion and go ahead and turn the WYE's on their side to connect horizontally. Hopefully that will make the venting situation even better like you stated.

 

[Stuff]

Can you post an updated picture with your changes?

The fixture drains need to connect horizontally to the horizontal wet vent. With that shower wyes need to be on their sides to prevent an s-trap. May have a problem with the main vent as it shouldn't go horizontal below flood level.

 

[Mliu]

I'm not a DWV expert, but it seems you have an awful lot of 90° elbows. My understanding is that you should eliminate as many 90° bends as possible to improve flow dynamics. And when you must have a 90° turn in flow, you must use long-radius 90° elbows or two 45° elbows. I can't tell from your diagrams if those are long-radius 90° elbows.

Also, I'm curious why the main vent doesn't go up near the soil stack (near the origin of your 3D drawing).