Common vent for washer standpipe & utility sink?


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Old 10-18-07, 12:13 AM
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Common vent for washer standpipe & utility sink?

Hi again,

While asking my last question, I started to second guess my washer standpipe and utility sink drain/vent configuration. Can someone tell me if this is generally considered legal?

I have a 2" pipe rising out of the slab. On it, a 2" santee points to the right and accepts the waste from the standpipe trap. Directly above that tee is another 2" tee facing left for the utility sink waste. The vent will continue vertically from the top of the 2nd tee. The whole thing is shaped like a cross, except that one arm is about 4" higher than the other.

Since the utility sink waste technically washes the standpipe's drain as it falls through the vertical drain pipe, have I inadvertently set up a wet vent situation?

If my configuration is legal, does it change the venting requirements? I was hoping to get away with a 1.5" vent.

If it's not legal, do I need to change it to something like this?
http://www.terrylove.com/images/washer_rough_b.jpg

The difference between my set up and the one in the photo iis the parallel vent off the standpipe trap that rejoins the other vent higher in the wall

Thanks again!
 
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Old 10-18-07, 09:42 AM
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Sounds like you have created 4" of a wet vent. Will it be a problem? Probably not (especially since you can control when the utility sink is draining, i.e., NOT when the washing machine is draining).

Possible things you could do:
1. Make the change you proposed.
2. Bring both drains into the vent stack at the same point with a double sanitary tee.
 
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Old 10-18-07, 10:18 AM
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Smile Wet vent

Originally Posted by lilfos
Hi again,

While asking my last question, I started to second guess my washer standpipe and utility sink drain/vent configuration. Can someone tell me if this is generally considered legal?

I have a 2" pipe rising out of the slab. On it, a 2" santee points to the right and accepts the waste from the standpipe trap. Directly above that tee is another 2" tee facing left for the utility sink waste. The vent will continue vertically from the top of the 2nd tee. The whole thing is shaped like a cross, except that one arm is about 4" higher than the other.

Since the utility sink waste technically washes the standpipe's drain as it falls through the vertical drain pipe, have I inadvertently set up a wet vent situation?

If my configuration is legal, does it change the venting requirements? I was hoping to get away with a 1.5" vent.

If it's not legal, do I need to change it to something like this?
http://www.terrylove.com/images/washer_rough_b.jpg

The difference between my set up and the one in the photo iis the parallel vent off the standpipe trap that rejoins the other vent higher in the wall

Thanks again!
What I see is your hook-up is fine I see no sign of a wet vent, do it by your picture, [A wet vent is a vent that receives the discharge from wastes] don't see it, luck.
 
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Old 10-18-07, 11:42 AM
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Thanks for your replies. Unfortunately, shacko, that's not a photo of my set up. It's one I found on the internet when I started to question mine.

I considered the double sanitary tee, but I can't remember why I ruled it out (I roughed this in 2 years ago and I'm finally framing now). It could be that I was worried about discharge from the washer shooting straight across the double tee. It's also possible that I couldn't find one at the store and decided that 2 tees would work just as well.

Since I don't have room horizontally to add a vent take off to the standpipe trap, I'll hunt down a double sanitary tee.

Thanks again
 
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Old 10-18-07, 05:44 PM
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if you go the double san tee route, you should install a test tee to be used as a clean out in the vertical pipe. double san tees can be trouble trying to get a snake through for the same reason you thought that the washer discharge might rush at the tubs drain. a sewer cable will want to go straight across the double tee and into the other fixture. just easy insurance against a future plumber that might not be able to figure out what's happening until he blows the p-trap under the laundry tub apart. if you're testing and inspecting the new work, you'll need a test tee below the double san tee anyway.




paul
 
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Old 10-19-07, 08:47 AM
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Oh, good call.

Since I'm cutting into the stack below the first tee, I'd need to use a coupler to extend the stack back up to the original standpipe trap height (because that's where the hole in the stud is). I can accomplish this with a test tee and kill two birds with one stone. Nice.
 
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Old 10-19-07, 09:10 AM
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Question Wet vent

.....I considered the double sanitary tee, but I can't remember why I ruled it out (I roughed this in 2 years ago and I'm finally framing now). It could be that I was worried about discharge from the washer shooting straight across the double tee. It's also possible that I couldn't find one at the store and decided that 2 tees would work just as well....

Thats the reason that most codes do not allow double tees on sanitary lines.

Too bad you didn't post a sketch of your proposed layout, luck again.
 
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Old 10-19-07, 09:39 AM
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Your proposed layout should work fine. You can also use a 1 1/2" vent. Whether it is strictly to code depends on your local jurisdiction and the codes you fall under.
 
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Old 10-19-07, 12:35 PM
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Thanks Chris.

Are you referring to the existing layout (two stacked tees) or the change to a double sanitary tee?
 
 

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