Advice Needed - WC Elbow, WC location on branch and clean-out location

[ProfessionalAmateur]

Two separate toilets here. Both will be wet vented via the lav’s In each bathroom. Both sides will tie into the main soil and vent stack (“main stack”) within a few feet via a double wye with 1/8 or double combo wye.

First picture - Of the four, which is the most best elbow option to use?
The WC is the furthest fixture and after the WC but before the main stack connection there will be a 3x3x2 combo wye to catch a shower and lav with the lav providing 2” wet venting. The distance from the main stack to the WC is 3ft.

Second picture - Is it okay for the WC to sit atop the branch with two 3x3x2’s before the WC? Should I have a clean out at the end or does it not matter?
The 3x3x2’s are fed by a shower on one side and lav on the other, with the lav providing 2” wet venting. The max distance from the main stack and the end would be exactly 3ft.

 

[wwhitney]

First picture--use for what? If up-down in the picture is up-down in space, then the middle two elbows may not be used for drainage in the orientation shown.

Second picture--this is a surprisingly complicated question. The issue is that the IRC wet venting requirements in P3108.1 conflict with the IPC wet venting requirements in 912.1.

Chapter 31 Vents: Vents, Virginia Residential Code 2021 | UpCodes

UpCodes offers a consolidated resource of construction and building code grouped by jurisdiction

up.codes

Chapter 9 Vents: Vents, Virginia Plumbing Code 2021 | UpCodes

UpCodes offers a consolidated resource of construction and building code grouped by jurisdiction

up.codes

Per the IRC, "Each fixture drain shall connect horizontally to the horizontal branch being wet vented . . ." so no, the configuration you show is not allowed by the IRC's plumbing section. The equivalent part of the IPC says "Each wet-vented fixture drain shall connect independently to the horizontal wet vent," so yes, the configuration you show is allowed by the IPC.

That leaves the question of whether for your building (which I assume is a single family dwelling) you must follow the IRC or have the option to follow the IPC. That varies from state to state and would typically be found in the scope sections of Chapter 1 of the codes as adopted by that state. But Virginia has so heavily amended Chapter 1, it's entirely unclear to me which code takes precedence.

Anyway, if you figure that out, you will know whether the configuration shown is allowed.

BTW, the 3x3x2 combo for the shower needs to be horizontal. That is, the total fall from the shower trap outlet to the point where the drain from the dry vented lav joins the shower to wet vent the shower is limited to one trap diameter (2") of fall.

Cheers, Wayne

 

[Sponsor]

 

[James Henry]

If you have to use an offset toilet flange I would look into a 10" rough-in toilet or use a street combo.

 

[wwhitney]

If you have to use an offset toilet flange I would look into a 10" rough-in toilet or use a street combo.

I've never seen a street combo in plastic, do they exist? You could try a street wye plus a street 45, presumably the gain on the horizontal would exceed the loss on the diagonal.

Cheers, Wayne

 

[James Henry]

I've never seen a street combo in plastic, do they exist? You could try a street wye plus a street 45, presumably the gain on the horizontal would exceed the loss on the diagonal.

Cheers, Wayne

You talk funny, are you sure you're in the trades.

 

[ProfessionalAmateur]

Gentlemen, thank you for the responses. Let me know when the boxing match starts.

First pic - I’ll go with the bottom option with 3” clean out.

Second pic - the flange in this will be straight not offset like the first pic.. My fault for the pic being incorrect. Wayne, I found it coufusing myself but I’ll continue researching and call the local ahj. Also, luckily, everything is fairly close so the 2 inch slope shouldn’t be an issue. Several of the drains only have 1/8” slope, maybe that was kosher in the 60s/70s?

fwiw, i look at the bottom option in the first pic as the equivalent of a street combo. Please don’t roast me.

As always, huge thank you to the pros for input. I missed my calling in life.