Island loop vent help

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Islandvent

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Having my kitchen renovated. A wall was removed by the existing sink countertop to create an island. The removed wall housed the vent for the kitchen sink. That vent from the roof was routed over to the wall a few feet from the island. When I checked the sink cabinet and crawl space after the plumbing was complete I saw what is drawn in black. I’m no plumber but it didn’t look right and read up on the code. The loop had two 90 degree elbows instead of the 45-90-45, and the apex was below the level of the bottom of the sink; the return vent was not connected to the horizontal drain pipe; and the foot vent was sloping in the wrong direction. After speaking to the contractor the changes made are shown in red.

The two remaining issues I see with the code (highlighted) are:

1. The return vent is connected upstream of the sink drain.
  • The location of the sink drain and main drain line to the sewer leaves no space for the return vent to be placed downstream of the sink drain
2. The island sink drain already serves the upstairs bathroom.
  • I’m assuming the sink drain and return vent would have to be angled away from the current drain and attached to a new sloped drain that connects to the main drain line to the sewer
Aside from not being to code, what are the implications of these two issues if they went unaddressed?
 

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breplum

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Well drawn !!!!! kudos for that.
The only way to do proper island plumbing is by code designated, tried and true methods.
Getting into the weeds on theoretical bad plumbing is not worth the effort IMHO.
You can read until the cows come home and beyond in these archives of how improperly plumbed systems perform.
 

Jeff H Young

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Islandvent , I dont get it ? no it doesent meet code fail you have your vent and drain swapped plus you fail for having additional fixtures draining from up stream . sorry to bear the bad news
 

wwhitney

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Beautiful drawing. If you have enough height, the two violations you list could be fixed by rerouting as shown below. Or the horizontal island sink drain could turn around and connect to the main separately.

Or the sink drain could be connected to the right hand vertical, with the foot vent connected to the left hand vertical, and again the sink drain turns horizontal above the drain from upstairs, hits the vertical return vent with a san-tee, and then hits the lower drain. I like this idea best but it would be harder to draw with all the crossings that aren't connections.

Cheers, Wayne

9DB134C0-DAD7-4AF6-B2DE-77ECF0F6EEE5.jpeg
 

Jeff H Young

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Yes agree drawing is very good, gotta do what you gotta do to get it right. this is exactly where Id be ok with an AAV I mean I know guys were routinly putting them in 20 years ago on tract homes and being inspected in San Diego County. Ive run copper vents up the side of an old house to satisfy code and many many hardships to meet code . Island venting per code does perform very well you wont later be disapointed though inconvienianced to comply now
 

Islandvent

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So something like these?
 

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wwhitney

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So something like these?
Yes. [BTW in all of your drawings, the "short sweep" on the right where the foot vent turns up should be a LT90.]

On the first one, at the orange bar (which I assume is an editing artifact), if the horizontal island sink drain is directly above and parallel to the lower drain, the minimum height option would be a street quarter bend into an upright combo. If they are parallel but not directly over each other, then you can roll that assembly as long as the quarter bend outlet is no more than 45 degrees from plumb. If you roll it more, then the quarter bend needs to become a LT90 (and maybe a cleanout becomes required?)

The second one might require a cleanout as the horizontal sink drain does a 180 horizontal turn.

Is the third option (that I didn't draw) not possible?

Cheers, Wayne
 

Jeff H Young

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There can be some issue with terminology short sweep as far as I know is only refered to cast iron. if your working with plastic Id call it a long sweep commonly called a long turn 90 (LT90) on supply house or paperworkor spec sheets
 

Islandvent

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Thanks for making the drawing. It matches what I described in the last paragraph of my first post.

Cheers, Wayne
Ahhh gotcha, I was having a hard time visualizing that. The only issue is that the left hand vertical is already so close to the main, as seen in my drawings, that I don’t think there would be enough space for all the other fittings to connect the sink drain horizontal down to the upstairs bathroom horizontal.

Thanks for the clarification on the LT90!
 

wwhitney

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The only issue is that the left hand vertical is already so close to the main, as seen in my drawings, that I don’t think there would be enough space for all the other fittings to connect the sink drain horizontal down to the upstairs bathroom horizontal.
Two comments: it doesn't have to connect to the horizontal drain from upstairs, it could go straight to the main line.

And my original idea was slightly different, I updated the drawing below. In the red box, if the vertical is directly over the lower horizontal, you could use, from bottom up, an upright combo and then a (possibly street) san-tee.

That is, while the UPC says the vent should reconnect to the horizontal island sink drain, nothing says that the outlet of that connection has to be horizontal. So it could be vertical via the san-tee.

Cheers, Wayne
Loop Vent.jpg
 
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Jeff H Young

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Two comments: it doesn't have to connect to the horizontal drain from upstairs, it could go straight to the main line.

And my original idea was slightly different, I updated the drawing below. In the red box, if the vertical is directly over the lower horizontal, you could use, from bottom up, an upright combo and then a (possibly street) san-tee.

That is, while the UPC says the vent should recconnect to the horizontal island sink drain, nothing says that the outlet of that connection has to be horizontal. So it could be vertical via the san-tee.

Cheers, Wayne
View attachment 86303
Not clear does the "return vent connect to the horizintal drain" or does it connect to a verticle section of drain. The wording could come into play. I dont think it matters and will function fine . no opinion on what inspector will say if anything combo inspectors are often pretty lax and not opinionated on code unless they have plumbing experiance or are trained on a certain code and get a kick out of pressing who the boss is. Then you have knowledgable inspector who really know the trade and code that get no pleasure making life difficult and actualy hate slowing down the job and causing hardship. so the inspector might take a look at it and see that it should function and have no reason to pick it apart
 

wwhitney

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Not clear does the "return vent connect to the horizintal drain" or does it connect to a verticle section of drain.
Interesting point of view. I'd say it connects to both--a horizontal drain on the upstream side and a vertical drain on the downstream side. I don't really see how you can say it only connects to a vertical drain and not to a horizontal drain. But I agree that it's not as obvious as I assumed.

Cheers, Wayne
 

Jeff H Young

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Interesting point of view. I'd say it connects to both--a horizontal drain on the upstream side and a vertical drain on the downstream side. I don't really see how you can say it only connects to a vertical drain and not to a horizontal drain. But I agree that it's not as obvious as I assumed.

Cheers, Wayne
Dosent need to be obvious you could be right . I would say the vent has a connection to a drain line that is either verticle or horizontal and that the code calls for horizontal so if indeed its a horizontal drain then your golden .
 

Islandvent

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Two comments: it doesn't have to connect to the horizontal drain from upstairs, it could go straight to the main line.

And my original idea was slightly different, I updated the drawing below. In the red box, if the vertical is directly over the lower horizontal, you could use, from bottom up, an upright combo and then a (possibly street) san-tee.

That is, while the UPC says the vent should reconnect to the horizontal island sink drain, nothing says that the outlet of that connection has to be horizontal. So it could be vertical via the san-tee.

Cheers, Wayne
View attachment 86303
 

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Jeff H Young

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I know pic in post17 meets code. the one in Post16 might be debatable . Ive never seen one that way , youll probebly pass give it a try let us know how it goes
 
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