Inspector discouraged AAV, which option works better?

[puyehue]

What about a combination waste & vent setup? Can you fit a 3" vertical pipe in the space under the window, connected to a 3" drain below the floor?

That would be a cool and effective way, but it looks to me as if UPC wants that for below-the-floor stuff.
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I think I could pull that off. I have a lot of space below and joists are going the right direction, and I can drop into main 4" easy.

Does anybody know if that is an acceptable option?

I could call my inspector, but I do not think he will know the answer.

 

[puyehue]

That would be a cool and effective way, but it looks to me as if UPC wants that for below-the-floor stuff.

Reach4, I think you are correct (unfortunately)


B101.2 General Requirements

Combination waste and vent systems, as outlined in Section 910.0 of this code, cover the horizontal wet venting of a series of traps by means of a common waste and vent pipe. Pipe sizes not less than two pipe sizes larger than those required for a conventional system are designed to maintain a wetted perimeter or flow line low enough in the waste pipe to allow adequate air movement in the upper portion, thus balancing the system.

Sinks, lavatories, and other fixtures that rough in above the floor, shall not be permitted on a combination waste and vent system, which, at best, is merely an expedient designed to be used in locations where it would be structurally impractical to provide venting in the conventional manner.

Combination waste and vent systems are intended primarily for extensive floor or shower drain installations where separate venting is not practical, for floor sinks in markets, demonstration or work tables in school buildings, or for similar applications where the fixtures are not adjacent to walls or partitions. Due to its oversize characteristics, such a waste system is not self-scouring and, consequently, care shall be exercised as to the type of fixtures connected thereto and to the location of cleanouts. In view of its grease-producing potential, restaurant kitchen equipment shall not be connected to a combination waste and vent system.

 

[Sponsor]

 

[wwhitney]

A dimensioned plan view drawing showing the 4x4s and the 4x6, the sink base and drain, the dishwasher, and any other cabinets would be helpful.

If the dishwasher is fully under the righthand window, you could locate the san-tee in the wall, with a horizontal placement between the 4x4 and the dishwasher. The trap arm would come out of the wall to the left of the dishwasher (possibly at a 45 in plan), and the vent would be in the wall, emerging to "cut the corner" around the 4x6, then turn up in the sidewall.

Cheers, Wayne

 

[Reach4]

A dimensioned plan view drawing showing the 4x4s and the 4x6, the sink base and drain, the dishwasher, and any other cabinets would be helpful.

If you run a 2 inch drain, that 5 ft max would be the "developed length" which is the path through the pipes and bends from the U in the trap to the sanitary tee.

You may be using three 45s, including one at, or just after, the trap adapter. So the sink would be pretty much by the dishwasher.

Going to have a disposal?

 

[puyehue]

If you run a 2 inch drain, that 5 ft max would be the "developed length" which is the path through the pipes and bends from the U in the trap to the sanitary tee.

You may be using three 45s, including one at, or just after, the trap adapter. So the sink would be pretty much by the dishwasher.

Going to have a disposal?

no disposal

 

[Jeff H Young]

the dish washer makes it interesting Ive notched out dry wall and studs just enough to make everything fit . not that fun usually that was when they changed kitchen around and moved dw. Just letting you know things to concider

 

[puyehue]

Jeff/ Wayne/ Reach4
After reading Wayne's last note, Reach4's sketch, and Jeff's encouragement, I have a solid plan.
Speaking with the designer, there is a small ~6" cookie sheet cabinet at the 4x6 corner, where I can tuck the 45 from santee.
And coming back out at the 4x4 will land right at the drain.
Thanks much for your thoughts!

 

[Reach4]

Good. Resist using a glued-in trap at the sink. Slip makes it really easy to reconfigure later, and to clean if needed. Use a trap adapter, and put in a slip trap.

Something I don't know is if you have a 1.5 inch slip trap on a 2 inch trap adapter, how does that affect that 5 ft max measurement?

Remember to maintain the 1/2 inch per foot slope the whole path. In particular, avoid going steeper.

 

[puyehue]

Ok, thanks for that. Slip it is.
All said, I'm coming in under 5 ft easy now, so no issues with distance.
I will do the slope.

Until the next puzzle.....

 

[Terry]

This may be a good spot for an Island sink vent.
Anywhere you go there will bite into structure. In the Seattle area, the AAV would have been fine. Did your inspector see the job or the photo's?
The inspector will want to see a 2" cleanout for the sink.

 

[Reach4]

This may be a good spot for an Island sink vent.
Anywhere you go there will bite into structure. In the Seattle area, the AAV would have been fine.

Is the island vent allowed by UPC for non-islands, or is this a local variation for your area?

 

[Terry]

Is the island vent allowed by UPC for non-islands, or is this a local variation for your area?

So much depends on local inspection. Normally a plumber would have enough inspections under their belt that they would have a rapport with the inspector ahead of time. I've used it when it can affect building structure before.

 

[puyehue]

Hi Terry, Thanks for your thoughts.
Jeff pointed out that the island vent would need to come as high as the drain board of the sink. In this situation, the counter height is window height, and with recessed windows, there is some 5+ inches of wood below window, so the stud bay is only 30" high. Jeff also mentioned bringing the island loop into the cabinet to max out the height of the loop, but noted the drawbacks of cabinet space, placement, etc.

I'm not a plumber but I do have a rapport with our inspector from previous projects. With no disrespect to the inspector, his background is other trades, and is open to "whatever works"..... so, that's why I'm here...... Lucky you guys.

Good point on the cleanout. In plan A, (5' 2" trap arm), I can fit it in the crawlspace, below san-tee, I hope?

 

[Jeff H Young]

trap size must match trap arm. Sounds like inspector be flexible , in which case whatever you choose.

 

[Reach4]

trap size must match trap arm. Sounds like inspector be flexible , in which case whatever you choose.

Good point. Jeff is referencing UPC "1003.3 Size" which states

"The trap shall be the same size as the trap arm to which it is connected."​

That would mean a 2 inch trap in your case. I find no slip 2 inch traps. If those are not available, that would call for a glued trap. Those are available in 2 inch with a union, which lets you swivel. All-glued may require more experience to get right.

If you bring in the pipe at an angle, there would be enough length to cut out a trap and glue (or couple) on something else if you had to make a change.

 

[puyehue]

Great stuff. Points well taken. Thank you both.

 

[wwhitney]

Remember to maintain the 1/2 inch per foot slope the whole path. In particular, avoid going steeper.

I think you mean 1/4" per foot? At 1/2" per foot, a 2" trap arm should be no more than 4'.

If I recall, IPC would permit 8' on a 2" trap arm, which works if you can get exactly 1/4" per foot, and the UPC limit of 5' is presumably based on the idea that you may be a bit over 1/4" per foot.

Cheers, Wayne

 

[wwhitney]

All said, I'm coming in under 5 ft easy now, so no issues with distance.

If you can get it under 3' 6", then you can go with the more usual 1-1/2" trap arm.

Cheers, Wayne

 

[wwhitney]

That would mean a 2 inch trap in your case. I find no slip 2 inch traps. If those are not available, that would call for a glued trap. Those are available in 2 inch with a union, which lets you swivel.

I believe you can still use a 1-1/2" sink tail piece with a 2" trap. Just glue a 2" x 1-1/2" bushing into the trap inlet, and then a spigot end 1-1/2" trap adapter. That plus a union trap will allow disassembly for cleaning.

Cheers, Wayne

 

[Reach4]

If you can get it under 3' 6", then you can go with the more usual 1-1/2" trap arm.

He can't get it that short; he is routing the trap arm under a window, behind a dishwasher, to a side wall. 5 ft could be a challenge.

I believe you can still use a 1-1/2" sink tail piece with a 2" trap. Just glue a 2" x 1-1/2" bushing into the trap inlet, and then a spigot end 1-1/2" trap adapter. That plus a union trap will allow disassembly for cleaning.

Yes, he can feed the 1-1/2 tailpiece into the trap adapter, since that is before the trap.
Sorta on the cleaning. Not nearly as much as a slip trap would have. And he will have to have the pipe he glues the trap to be a precise length. Slip eliminates the need for precision. In a pinch, he could use a shielded coupler as almost-a-union in the early part of the trap arm.