180 degree turn on 3" toilet drain

[gindo]

Hi there, perhaps someone can offer some guidance.

I'm renovating a mid 1920's bathroom, and am moving the toilet to a new location. The old one sat right in front of the stack, and I plan to put a wall mount toilet in the far corner of the picture where you see some copper which used to supply a sink. By going with a wall-mount toilet I get to avoid structural work in my joists, since my 3" drain is above the floor, and I can drop it into the chase where I need it.

Here is my question.
What am I allowed to do in terms of doing a 180 degree direction change on the flow while dropping down? I'll be coming from the exterior wall (back left in the pic), and need to enter the front of the stack where you see the gasket.

I propped up a few parts at hand - a standard 90, and two 45's just as a quick illustration. Can I create an assembly like that? Does it matter if I use long sweep for this? (The 3x3x2 is there for a shower and sink drain.)

thanks for any guidance!

 

[Jadnashua]

That would not meet code as I understand it. You can't have more than 135-degrees without a cleanout, and it would need to be accessible, which isn't going to happen between floors like that. ANd, it still would need the minimum of 1/4" per foot drop of the horizontal sections.

 

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[gindo]

That would not meet code as I understand it. You can't have more than 135-degrees without a cleanout, and it would need to be accessible, which isn't going to happen between floors like that. ANd, it still would need the minimum of 1/4" per foot drop of the horizontal sections.

Thanks for this, Jim.
I'd come across this 135 degree rule before on the Terry Love forums. It wasn't clear whether this applies only to horizontal direction changes, or also vertical drop?
I'm inclined to think that you could drop down on a second story through a wall, and then in the basement have another 90 before hitting the stack. You'd then be at 180 degrees, and that wouldn't be with a cleanout upstream. So it seems to me this 135 degree rule is intended for horizontals, not vertical direction changes. But would love to hear someone confirm which is right.

If indeed it does apply for vertical direction changes also:
The horizontal section before the drop will actually be above floor level, buried in a low bulkhead perhaps 6" high or so above floor level. That low bulkhead is also a shower kerb, and have a shower glass partition standing on it. I could put a clean-out on the upper horizontal prior to the drop and the hairpin turn, and an access panel from the outside of the shower. Seemingly that would get me there. But it still seems peculiar to require a cleanout on vertical direction changes.


And additionally, based on some reading I've done, I should have a long sweep on the bottom of the drop.

(I'm a pretty handy DIY'er, so just brushing up on a few points. I do have a building permit, but I don't want to rebuild stuff all glued into place when the inspector shows up!)

 

[hj]

HOW would you have a 135 degree offset in a vertical stack?

 

[gindo]

HOW would you have a 135 degree offset in a vertical stack?

Since my post above I did a bit more reading online, and as far as I can see, this 135 degree rule is only for horizontal direction changes.

I'll have a horizontal 90 degree turn coming off the wall mount Gerberit unit. After that, so long as I drop into a long-sweep 90 on the drop to the opening on the stack i'm in the clear.

 

[Jadnashua]

You might simplify things if you removed the CI (or it looks like it might be lead) part from the hub, and built things back up from there. FWIW, that unbanded, unreinforced rubber coupler that is there now is NOT approved for use above ground, and it looks like you have two different size pipes and it is reducing. If you get the pipe out of the hub, you can use a reducing donut, switch it right there with 3" pipe, and give yourself some more space to work. As your mockup is right now, the run would end up above the subfloor, which would need something to cover it. If you came out of the hub with maybe a street elbow, you could angle things back where they need to go easier, or a short stub, if you need another inlet. If you ever needed to snake what you propose, it would be really hard, and you could poke a hole through that rubber sleeve in the process, assuming you could get the snake that far.