Drain for 2 washers

[Searls03]

Hi, this may be a stupid question, but I am wanting to install a second washer in my house. I currently have a 2” drain line that runs over to a 2” stack (at least above ground it’s 2” anyways).

can I set up two ptraps and two stand pipes on this drain line (with proper venting of course). Or could this cause a back up?
Second option I thought of (not preferred if option 1 works) is could I run two 2” lines over to the 2” stack, one for each washer. Again with a vent, standpipe, and ptrap for each one.
Hopefully this make sense? Can anyone offer any help on this?

 

[Jeff Handy]

Post pics of current setup.

Then make a diagram showing existing and proposed piping layout.

Pros on here can advise, and can revise your diagram.

 

[Searls03]

I don’t have a set up yet. Making sure this is able to be done before I start with the existing pipe that is there (just a 2” pipe with only one washer on it currently). Here is a diagram of what I am sort of trying to figure out if it is able to be done or not. Mostly worried about the capacity of the 2” drain line and being sure it can take both washers draining.

hopefully this helps

 

[Jeff Handy]

Do you have room to add a utility sink?

That would likely fix all the issues.
Without a sink, it is unlikely that a two inch line could handle drainage from two modern washing machines at the same time.
They pump out really fast nowadays, and with high volume.

But pros here might have better ideas.

 

[Searls03]

What do you mean do I have a utility sink? I plan to add one in, yes....but why would it make a difference?

 

[Jeff Handy]

You can drain the washers into the sink, which can accept the high discharge rate better than a standpipe.

It acts as a holding tank, letting water drain out that will not overwhelm the capacity of the 2 inch line.

The sink strainer and trap needs to be kept clear of lint at all times.

The sink has to have a nice loose strainer design, to not choke off the draining water.

If both washers happen to drain at the exact same time, I suppose it could even flood a utility sink, pros in here can advise.

 

[Searls03]

You can drain the washers into the sink, which can accept the high discharge rate better than a standpipe.

It acts as a holding tank, letting water drain out that will not overwhelm the capacity of the 2 inch line.

The sink has to have a nice loose strainer to not choke off the draining water.

If both washers happen to drain at the exact same time, I suppose it could even flood a utility sink, pros in here can advise.

What about one in a standpipe and one in the sink?

 

[Matt30]

Under my code you can’t connect two Ptraps in that manner. Look up a photo of a dual vent set up. Use a double sanitary tee on the stack and each branch will be a connection for your trap and standpipe

 

[Searls03]

Under my code you can’t connect two Ptraps in that manner. Look up a photo of a dual vent set up. Use a double sanitary tee on the stack and each branch will be a connection for your trap and standpipe

That makes sense and would be a lot easier to set up. Is a 2" pipe enough tho for two washing machines to not cause a backup? Im not a plumber, so don't understand code entirely...but in my are we use upc 2012. My understanding is that a 2" pipe can have 4 fixture units and a washer is considered 2....so 2 washers would be 4. But in practice, is it really enough to have both washers on the same pipe if they happen to both drain at the same time?

 

[Matt30]

Yes it will be fine. My fixture units (NPC) are a little different but it will still work. Your 4 fixture units is for your horizontal branch. A 2” stack can handle more. If my code book was handy I would look it up

 

[Searls03]

Ok so I have decided to do the Y configuration with the vent coming straight off the top of it.
I am running into an issue with the vent tho. I have to run the vent approx 25 feet around a corner to reach back to the stack. The electrical panel is on the wall lower than the flood level of the washer standpipe. Can i start the vent off below flood level and then once I pass it raise it to above. Or should I try to find an alternate route where the pipe can go straight up rather than make a 90 degree turn right away?
Hope this makes sense?