No vertical room for a Standard P-Trap, is Running Trap permitted?

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Lehighlager

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Looking for some advice on how to plumb a floor drain where there is not much vertical distance between the top of the floor drain and the existing waste pipe.

plumb-diagram-small.jpg


I've included a diagram of what I want to do, labeled A. Basically the trap would be in-line with the 3-inch waste pipe (waste pipe of course slanted down 1/4 inch per foot). I think that this used to be called a running trap and I know they are no longer o.k. for an entire house, but could they be used for a single "fixture". If not allowed, what is the minimum clearance needed from top of drain to start of P-trap?

As an auxilliary question, if this type of running trap for single fixture were permitted, what are the clean out requirements, i.e., how far can the clean out be away from the trap and what (if any) direction change in the 3 inch pipe is permitted? Thanks much.

Diagram B just shows what a normal P-trap would look like in this situation if there were enough vertical space.

Wasn't sure if to post this here or in code section, sorry for being new!
 

Lehighlager

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YOu do realize that the vertical distance is MORE for the running trap because of needing two elbows, don't you?
I do realize this, it is too complicated to explain in text, but, I can dig a hole for the "running trap" but I cannot get the waste pipe to go any lower (it has to eventually exit through a hole in a very thick concrete wall which is just a few inches below the bottom of the trench drain. Complicating the issue is that I have to vent the drain on the drain side of the concrete wall. Long story short, I am aware of your point.
 

wwhitney

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It sounds like you are thinking of putting the vent inside and the trap outside. The vent has to be downstream of the trap.

Cheers, Wayne
 

wwhitney

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So per Charlotte's catalog, if you take your horizontal trench drain outlet and hit a street quarter bend into a 3" solvent weld p-trap, the outlet of the p-trap will be 11/16" lower than the quarter bend inlet. Can you afford that amount of drop, and can you put the p-trap fairly close to the trench drain?

Cheers, Wayne
 

Lehighlager

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So per Charlotte's catalog, if you take your horizontal trench drain outlet and hit a street quarter bend into a 3" solvent weld p-trap, the outlet of the p-trap will be 11/16" lower than the quarter bend inlet. Can you afford that amount of drop, and can you put the p-trap fairly close to the trench drain?

Cheers, Wayne

I can as long as the code permits only an 11/16 drop, which is the question at hand! Just making sure that this would not be a prohibitted "running trap".
 

wwhitney

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Yes, good question. I'm not familiar with all parts of the IPC, but I would think any prohibition would be in Chapter 10 on traps, and I didn't see anything in a quick review:


1002.1 has a maximum tailpiece length, but I don't see a minimum tailpiece length.

What is this trench drain for?

Cheers, Wayne
 
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