Is there any way to drain this sink to the sewer line, under a door? Code on P-Trap shape?

[TheOverThinker]

Is there any code compliant way to get waste from the diagrammed location, under the door, and to the sewer line?

Other than a 4" tail on a P trap, are any other parts of the trap regulated?
In other words, could a trap be made with a lower part 3 feet wide, kind of like diagrammed in green?

In the above example the AJH prohibits Air Admittance Valves.
A vent is possible at any point along the above lines.
Intercepting the sewer is expensive and uncertain (aside from risk to 90 year old cast iron pipes).​

 

[WorthFlorida]

Trap must be within 24 " of the sink drain. You can add a drain pump but still needs to be vented to the outdoors.
https://www.supplyhouse.com/Liberty...1rj5F4_8glwROmqovfMyPnmRVODIQpGYaAiAIEALw_wcB

 

[Sponsor]

 

[TheOverThinker]

Is there any rule against having TWO traps. One directly below the sink. The second farther down the line. The below sink trap would be for safety. The under door trap would not be a safety matter, just need to have a cleanout in case it clogs.

If done, would that require two vents, or just one?

What code provisions might apply?

 

[Reach4]

Horizontal stuff slopes 1/4 inch per foot.

If you cannot enter the cast iron that low, can you raise the door?

If neither, pump.

Yes there are rules against two traps.

 

[TheOverThinker]

Horizontal stuff slopes 1/4 inch per foot.
If you cannot enter the cast iron that low, can you raise the door?
If neither, pump.
Yes there are rules against two traps.

The diagram was not to scale.
The slopes don't work out. The under door pipe just barely clears the slab as is.
The door threshold already accommodates a 1" galvanized gas line, thus there's not much flexibility.

What section of code prohibits two traps, or a downstream trap? Surely the reliability of the pump is worse than the second trap!

 

[WorthFlorida]

Here is your problem with the cast iron, not the easiest thing to cut unless you have the right tools. Also it’s weight. You cut a section out and a few hundred pounds of weight could be overhead so you need to support it before and after cutting.

Two traps are not allowed regardless of venting since it won’t drain. A Pump is your best option, even cost wise and you’ll be able to cut into a overhead smaller pipe. Please do not keep asking the same question to get an answer you want. A lot of guys here are saying the same thing. If you want to go this route to the CI, then hire a plumber and it will cost more than a pump, electric and venting.

https://www.libertypumps.com/Portals/0/Files/Install Manuals/7212000.pdf

 

[TheOverThinker]

If you want to go this route to the CI, then hire a plumber and it will cost more than a pump, electric and venting.

Indeed, this is hard enough I will hire a professional plumber subcontractor for implementation either way.
You make a good point about going higher. If pumped about 8 feet up, 15 feet over the line can eventually reach 2" CI which is easier to snap.
I do realize that cutting the CI clearly involves first supporting it, then using a big soil pipe cutter.

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However, there are two arguments for cutting into the CI at the slab height: laundry sink, plus output of pumped 1.5" efficiency kitchen sink.
To pump both would require two pumps, and the risk that comes with pump failure.
I prefer to avoid mechanical pumps that will fail over time.

Two traps are not allowed regardless of venting since it won’t drain. Please do not keep asking the same question to get an answer you want.

I'm not seeking the answer I want, but a code citation. Yes it's an unusual situation, but I'm trying to figure out if there's any reason it would not work physically, or via the plumbing code. I can't see that it matters if the second (downstream) trap empties via siphon for example, as the first (upstream) trap will prevent sewer gasses from rising.

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Please note I'm code limited to a 1.5" line for the efficiency kitchen. 2" is not allowed.

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Or thinking of solving another way:
Is there any code reason that would prevent the existing 4" cleanout at slab level from being repurposed
as the drain?

 

[JohnnyCom]

California Plumbing Code 1004.1 “No fixture shall be double trapped.” Also, 1003.1: “Each trap, except for traps within an interceptor or similar device shall be self cleaning.” Doubtful the wide trap would be self-cleaning. Also 1003.1: “Traps ... shall be of standard design...“


.

 

[TheOverThinker]

California Plumbing Code 1004.1 “No fixture shall be double trapped.”

Thank you for the code citation!
https://up.codes/viewer/california/ca-plumbing-code-2019/chapter/10/traps-and-interceptors#10

I found this on double traps : https://www.hvacrschool.com/drains-and-double-traps/
"The double trap causes drainage issues because air becomes trapped between the two traps and air is lighter than water. This causes the air to want to travel up as the water flows down resulting in NO DRAINAGE."

Though it appears a second vent and a cleanout would solve the technical (not code) problems.

 

[James Henry]

Problem solved.