Adding utility sink to laundry standpipe

[DirtyJerz]

I've seen a bunch of earlier threads on this but wanted to confirm my understanding for my specific situation in New Jersey.

Current setup is a 2" standpipe without its own vent. NJ uses NPC (yes, this is a thing) and standpipes do not require their own vents as long as you have an air gap (or so it seems to me from my reading of the code). Utility sinks connected to a standpipe do not appear to require a vent either.

Here's a picture of the existing setup:

http://www.lensovet.net/~macuser/images/IMG_3034.jpg (I seem to be unable to either upload or insert images inline, so here's a link)

My plan is as follows:

- cut the standpipe in half
- 2/2/1.5 san tee at cut location
- 1.5" 90º fitting/sweat elbow
- 1.5" fitting/slip adapter
- 1.5" tubular from the utility sink drain to the adapter (no trap)

Is this all reasonable or am I going to have issues?

 

[Jeff H Young]

Totaly forieghn to me but if that works and meets code and sink is close I see no reason why adding a sink there woudnt work fine adding one to standpipe meets most codes if withen 30 inches but that (existing) would be called a mess in my code

 

[Sponsor]

 

[DirtyJerz]

lol scratch everything I wrote regarding venting, state compliance hotline told me that apparently this was acceptable at time of construction but no longer is. So adding a sink would require adding a vent.

AAVs are allowed. Can we just convert the standpipe into a vent and put an AAV on top of it?

 

[Jeff H Young]

you should be able to cut the trap arm just downstream of the ptrap install a combi on back (the verticle will become the vent) put your p trapback on and rebuild as you planned. Unless your code dosent allow tieing a sink into a standpipe most codes are ok with it but NJ is a world of its own I guess

 

[DirtyJerz]

You’re saying this would be the way to do it with an AAV?

 

[DirtyJerz]

you should be able to cut the trap arm just downstream of the ptrap install a combi on back (the verticle will become the vent) put your p trapback on and rebuild as you planned. Unless your code dosent allow tieing a sink into a standpipe most codes are ok with it but NJ is a world of its own I guess

So just to confirm this would be the layout correct? The triangle is where the AAV goes and the vertical pipe is the existing standpipe. Rectangle is the new sink.

 

[Jeff H Young]

Sure Im assuming NJ allows AAV that would be where you put one. but if it dosent its common code for much of the world .

 

[wwhitney]

Current setup is a 2" standpipe without its own vent. NJ uses NPC (yes, this is a thing) and standpipes do not require their own vents as long as you have an air gap (or so it seems to me from my reading of the code). Utility sinks connected to a standpipe do not appear to require a vent either.

NSPC reference to the above statements? I would be very surprised if the NSPC has those allowances to skip a vent.

Cheers, Wayne

 

[Jeff H Young]

NSPC reference to the above statements? I would be very surprised if the NSPC has those allowances to skip a vent.

Cheers, Wayne

post number 3 clears up that its not legal to have it unvented

 

[wwhitney]

So just to confirm this would be the layout correct?

Not quite.

You'd generally have two traps, one for the standpipe, one for the utility sink. Depending on the vertical wet venting allowances in the NSPC, you could take that wye with horizontal barrel already installed on the primary horizontal drain, and put a street 45 pointing up into the wye's branch inlet (rather than the 45 you have now with its inlet horizontal). Above that would go two san-tees for the two fixtures' trap arms (in the proper order per the vertical wet venting rules). And then above that would be the AAV.

Or if it's a convenient geometry, you could use a single san-tee with sanitary side inlet to connect both fixtures at the same elevation, then there would be no need to check the vertical wet venting rules.

Or you could leave the horizontal inlet street 45 in the existing wye on the primary horizontal primary drain, and upstream of it install a horizontal wye for your two fixture trap arms, and then use two AAVs, one each horizontal trap arm. Or use two vent takeoffs on the two trap arms, which rise to at least 6" above the fixture flood rims, combine and then go to one AAV.

If the above isn't clear (it's a lot of text), pick the one that sounds like it might work best for your layout, and I can draw it out.

Cheers, Wayne

 

[Jeff H Young]

Dirty Jerz post number 6 you drew it up ? and talked about putting a santee in the standpipe for utility sink in post number 1 . certainly more ways to do it including putting a real vent in instead of aav but I was going with basic function and conventional practice . Cant figure out why you want to change so much from original idea besides adding an AAV?
Are you pulling permits or trying to conform to your code?

 

[DirtyJerz]

Wayne, thanks for chiming in, I don't really need to keep the standpipe, so in my picture, I've converted the standpipe into a vent which terminates with an AAV (which would be acceptable per an email from the state code compliance office). Or at least that's what I thought we were doing based on Jeff's post #4 Ultimately I need a sink in here so that I can hang more washer drains on it (three total, two full-size and a pedestal one). I'm fine to remove the standpipe completely and have the sink replace it.

Jeff, I want to pull permits so this needs to be made current with today's code, which would require a vent, thus the change of plans. I thought my drawing was what you were suggesting?

 

[wwhitney]

Wayne, thanks for chiming in, I don't really need to keep the standpipe, so in my picture, I've converted the standpipe into a vent which terminates with an AAV (which would be acceptable per an email from the state code compliance office)

Ah, then your drawing is fine. But you can't convert the standpipe directly into a vent, you'll have to remove the standpipe trap.

So you can remove the standpipe and trap and rebuild from there to match your drawing.

Cheers, Wayne

 

[DirtyJerz]

Ah, then your drawing is fine. But you can't convert the standpipe directly into a vent, you'll have to remove the standpipe trap.

So you can remove the standpipe and trap and rebuild from there to match your drawing.

Cheers, Wayne

Yep, that was my thought. Keep the wye as is, disassemble the trap and standpipe. Put a combo (is that right? or should this be a santee because it's for venting?) on its back, stick the old standpipe going straight up, add an adapter to the top of it and attach the AAV to that. Then going to the right just do a long sweep 2" 90º elbow followed by a 2 → 1.5 reducing bushing and a sweat → slip adapter. Rest of the way is vanilla tubular with trap and the rest.

Might need some extra pipe to make things line up properly in terms of distances, but that's the general idea. All good?

 

[wwhitney]

Put a combo (is that right? or should this be a santee because it's for venting?) on its back

Combo is better. San-tee might be allowed in the NSPC, not sure; the IPC allows it but the UPC doesn't.

Then going to the right just do a long sweep 2" 90º elbow

Presumably horizontal (2% slope on inlet), as the trap arm has to be horizontal until it is vented.

The rest is fine.

Cheers, Wayne

 

[Jeff H Young]

Trying to help you out here and this forieghn code is quite the hassel I cant see where an AAV is allowed it might come under appendix E or elsewhere. its an interesting code very differant than others I read somewhere that it needs aprooval but cant confirm or remember

 

[DirtyJerz]

Yes AAV are described in section E.8. This project in my reading is compliant with E.8.2. Since this wouldn’t be a branch relief vent, E.8.3 doesn’t apply. I guess the one place where I could get in trouble would be if my overall roof venting is considered insufficient (E.8.5.2); currently I have 4 vents, which I presume are for (1) kitchen sink (2) lavatory sink (3) WC + shower and (4) lav + WC in powder room downstairs.

 

[DirtyJerz]

Presumably horizontal (2% slope on inlet), as the trap arm has to be horizontal until it is vented.

Yes the 90° would be to take the pipe away from the wall toward the interior of the room.

 

[Jeff H Young]

E8 refers to special design plumbing systems correct? Generaly such things arent automaticaly aprooved but can be as easy as inspector saying sure thats fine or saying no . Try looking at E.1.4 Im not familiar at all with your code . I think you should talk with an inspector because youve got a lot of ideas so far every step of the way might be trouble of cource redoing it might be easier than talking to some of them . It sounds like you might not be qualified to desighn a special plumbing system then again it could be easy as pie and he just signs the card

 

[DirtyJerz]

Some of my inspectors aren’t great. Frankly the state compliance hotline has been a million times more helpful (that’s a thing we have here).

Wayne, could I ask you to make me a diagram matching what I described? I’m not good at these things…