Outside Branch Drain extension with SDR35

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BobinWA

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Hello,
I have an existing branch drain for RV dump, under a cement slab in a carport. I want to move the RV dump to the upper part of the lot, about 35 feet away, and about 5 feet higher in elevation. My local code says anything outside needs to use gasketed SDR35. I'm fine with the main portions of that job.

I'm looking for the best way to tie into the existing schedule 40. I have cut the concrete around the existing 90 for the RV dump. I can cut it out, but I'd like to have it become a cleanout. My problem is the top of horizontal pipe is into the bottom of slab, which is 3 inches, if I'm lucky. I'm thinking the only way for a cleanout is to install a Wye or some type of combo with a sweep. It seems like both of these options will result in something much higher than top of slab. Any suggestions? I'm thinking of just moving the cleanout spot upstream to a place where I have enough room.

Second, what is the best way to transition from the SDR35 to Sch. 40? I'll need to cut the spigot end of the final pipe to the correct length first, then join it to the Sch. 40 how? I want to make sure I don't have any mismatched inside diameters that could cause a backup and clog.

Finally, what's the best way to create a chamfer on the cut end of the SDR35?

Anything else that comes to mind, would be appreciated.

Bob
 

Jeff H Young

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local code won't permit sch 40 solvent weld under a carport Slab? I use sch 40 for everything unless I'm trying to save money on a lot of footage
 

wwhitney

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A two-way cleanout fitting has the same radius of curvature as a LT90. For the 4" size, I think the hub on the side extends ~4" past the hubs on the straight path. A san-tee on its back would stick out less, although doesn't seem quite proper. A vent tee or test tee would be even shallower.

To solvent weld a 4" SDR35 pipe to a Schedule 40 hub, you can use an adapter bushing, such as this one:

https://www.supplyhouse.com/Spears-P118-040-4-PVC-DWV-Adapter-Bushing

Cheers, Wayne
 

BobinWA

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local code wont permit sch 40 solvent weld under a carport Slab? I use sch 40 for everything unless Im trying to save money on a lot of footage
The existing dump spot is about 18 inches from the outer edge of the carport slab. I can use sch 40 and solvent under the slab. However, the new extension of the drain line is outside the carport area. Our municipal code says this must be SDR35. I had the city public works director come look at what we are doing and he verified the need for SDR35. So I need to transition from that SDR35 to the existing sch 40 - at the point where the current RV dump port is.
 

BobinWA

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A two-way cleanout fitting has the same radius of curvature as a LT90. For the 4" size, I think the hub on the side extends ~4" past the hubs on the straight path. A san-tee on its back would stick out less, although doesn't seem quite proper. A vent tee or test tee would be even shallower.

To solvent weld a 4" SDR35 pipe to a Schedule 40 hub, you can use an adapter bushing, such as this one:

https://www.supplyhouse.com/Spears-P118-040-4-PVC-DWV-Adapter-Bushing

Cheers, Wayne
Thanks Wayne. This makes sense. I though about the san-tee or vent-tee. This not only doesn't seem proper (pretty sure it's not :) ), but I asked the city guy about it and he said I need some type of wye not tee. So I don't think he'd pass it on inspection.
 

wwhitney

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Thanks Wayne. This makes sense. I though about the san-tee or vent-tee. This not only doesn't seem proper (pretty sure it's not :) ), but I asked the city guy about it and he said I need some type of wye not tee. So I don't think he'd pass it on inspection.
Well, a cleanout-tee can be used for a cleanout when the edge of the tee is approachable (e.g. on a vertical stack in the open). And a cleanout tee is just a vent tee with a threaded side entry. So I don't see why you couldn't use one on its back if the plug would end up flush with your concrete.

Most likely it would be a little low, which is why I suggested the san-tee on its back. Or you could use a vent-tee with a cleanout spigot adapter (a street female adapter) to gain a little height.

I think the need for proper curvature would apply when you have to add pipe to extend the cleanout opening to a distant access point. When the cleanout is right at the fitting, it doesn't see necessary. I mean, if the edge of the horizontal hub is only 3" below top of slab, then it's geometrically impossible to have a cleanout in the plane of the top of the slab and have more curvature.

So on further consideration, I'm going to say that in this particular application, a san-tee on its back would be fine, and what the inspector is asking for is geometrically impossible at that location. You could, of course, go downstream to where the pipe is deeper and install a two-way cleanout fitting there. At the edge of the slab, you could try a horizontal wye rolled up as much as possible, with a removable plug and maybe in a ground box.

Cheers, Wayne
 

Jeff H Young

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sch 40 is a higher standard then sdr 35 ne3ver heard of sch40 prohibited
 

John Gayewski

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The sdr 35 requirement is very odd. I know for a fact that sdr 35 does "oval" when buried, over time. It's not legal here for sewer piping. It's only used for very shallow storm drainage.

Also an sdr 35 bell on 4" pipe will fit inside of a schedule 40 fitting.
 

wwhitney

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Also an sdr 35 bell on 4" pipe will fit inside of a schedule 40 fitting.
Yes, I forgot that. So that's another way to get a bushing, just cut the bell end off a solvent weld SDR35 pipe. But the OP says he has to use gasketed pipe, so the bell may be different.

Maybe for some reason local soil conditions will cause a fair amount of movement around the pipe, and the gasketed connection performs better than a solvent weld connection? Otherwise seems odd to prohibit Schedule 40.

Any thoughts on the shallow cleanout fitting and what's reasonable/allowed?

Cheers, Wayne
 

Jeff H Young

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A wye on its side with a 45 or 22.5 looking up might be able to fit inside a c/o box the most shallow possibility come to mind at moment
 

wwhitney

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a wye on its side with a 45 or 22.5 looking up might be able to fit inside a c/o box the most shallow possability come to mind at moment
The OP specifies that the top of the Schedule 40 pipe is 3" below the top of slab. So what's wrong with a cleanout tee or san-tee on its back?

BTW, UPC 707.6 on cleanout extensions says that "they shall be extended from a wye-type fitting or other approved fitting of equivalent sweep." But if there's no extension, I don't see why you need the sweep. 3" is too shallow for an extension.

https://up.codes/viewer/washington/upc-2018/chapter/7/sanitary-drainage#707.6

Cheers, Wayne
 

Jeff H Young

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The OP specifies that the top of the Schedule 40 pipe is 3" below the top of slab. So what's wrong with a cleanout tee or san-tee on its back?

BTW, UPC 707.6 on cleanout extensions says that "they shall be extended from a wye-type fitting or other approved fitting of equivalent sweep." But if there's no extension, I don't see why you need the sweep. 3" is too shallow for an extension.

https://up.codes/viewer/washington/upc-2018/chapter/7/sanitary-drainage#707.6

Cheers, Wayne
Nothing wrong at all with your idea Wayne. its a good way since its shallow it shouldn't be an issue getting the snake to go in desired direction.
I brain farted but again you are correct on if the c/o if it needs extended it wouldn't meet code unless it has proper sweep but even then if its just an inch or 2 a santee could be used with a short (very short) piece of pipe and cut flush with slab using a "TOM CAP " style clean out and plug. saving cost and hassle of setting a c/o box.
 

John Gayewski

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I think a clean out tee is the only way to go. "Box it out" with something that'll work. A cast iron body with removable grate would be nice.
 
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