Drain Standpipe lengths

[ContractorDave]

I looked, honest I did. Somewhere in 13 there's a table or paragraph specifying the length and size of drain pipe standpipes or risers. I have a mechanical drawing where they are proposing to put a 6x3 reducer on a 6" piece of 3" on a p-trap for the 2" main drain. Doesn't seem near long enough to me.

Regards
Dave

 

[PEDARRIN2]

Don't know about the table, but a 2" drainage pipe flowing full will flow 13 gpm at 1/8" per foot.

With ~6+" of piping above the p-trap, you will get a little head pressure, but that will not likely be enough to flow the drainage from a test on a main drain.

Sounds like a recipe for floor puddles.

 

[cdafd]

lightecho

is the question how close should the pipe be to the drain??

or how big of drain pipe off the system should it be??

I agree draining into a floor drain does not work

 

[ContractorDave]

I was sure I read somewhere a spec of sorts for how tall a drain stand-pipe should be. Now that I think about it perhaps it's in one of my FP Handbooks. Anyways, yes, it's a rare occasion when a floor drain will actually properly take a full 2" flow.

Regards
Dave

 

[PEDARRIN2]

I like to take them outside whenever possible, but if it is not possible, I try to take them to a janitor's sink. There you have a 3" or 4" pipe and you have the 12" of the sides of the sink to act as containment and allow for 12" of static to help drain the water. If a janitor's sink is not close, I will use a hopper type drain and 4" pipe to drain/contain the flow.