Please critique my Island Sink plan

[JuanSigned]

I'm doing a complete remodel of my kitchen. Part of that has a new island for the kitchen sink and dishwasher. I've googled loop vents and Air Admittance Valves (AAV) till I think I understand how they work. I like the idea of a loop vent because there's nothing to go wrong and it's silent in operation, but the venting in my unfinished basement leaves me with a question. There are 2 drains vent connected to the horizontal run of the existing the dry vent before it goes vertical to the roof. Is the drain/venting plan I've drawn in green and blue in the picture OK?

 

[hj]

The green vent CANNOT connect to the "dry vent" until AFTER it rises 42" above the floor.

 

[Sponsor]

 

[JuanSigned]

The green vent CANNOT connect to the "dry vent" until AFTER it rises 42" above the floor.

Thanks HJ. There is another option for a vent that would meet that requirement, but it would be even more effort and cost. My local code allows for AAV's so given a choice between a loop vent and an AAV what would you do in your house?

 

[hj]

loop vent.

 

[JuanSigned]

OK, lets try plans B and C

Plans B and C tie into a vent that used to serve the old kitchen sink. That 2" vent runs vertically to the attic where it connects to other vents and goes through the roof. It is further away but still accessible.

Plan B removes the dry vent used in the first plan and the footer connection to the island drain. That's the only way I can see to keep the loop vent always slopping towards a drain. Plan B also vents the left drain which I'm guessing is going to be an issue. (even though the left and right drains joint under the slab just about where I'm standing in this picture)

Plan C is the most work, but it looks the closest to the drawings I've seen on the Internet. There is still that pesky business about the loop vent having to always slop towards a drain, so the loop vent connection has to be lower on the stack.

Is either plan OK?

 

[JuanSigned]

Bump

 

[Reach4]

I am not a plumber, but I am wondering if you should add cleanouts.

 

[JuanSigned]

I am not a plumber, but I am wondering if you should add cleanouts.

Cleanouts are in the plan, but above the floor. Two are going in the sink cabinet one for the drain and one for the vent, and one is going in the vertical section of the vent pipe. When all is said and done I will be able to get a snake through the whole system. At some point I'm going to finish the basement and all of what you see in the pictures will be behind drywall.

 

[Reach4]

It seems to me that I read a cleanout is needed every time you go more than 135 degrees of fittings. Maybe I am mistaken. It looks to me as if you have 270 in the blue line from upstairs if your turns are all 90 degrees.

I don't know if there is a requirement for vent cleanouts.

 

[JuanSigned]

Maybe a line drawing will be easier to understand. This is roughly plan C. The difference between this and the idealized drawings I've found on the internet is where the loop vent ties into the drain. I think this will work, right?

 

[JuanSigned]

Bumping this back up to the top. I've googled till my fingers bled and found nothing about loop vents other than the "idealized, perfect world drawings" I'm considering going with an AAV because I know I can install that correctly. Please, before I install a device that some think is an item straight from Hades, look at my ideas. My local jurisdiction follows the 2012 International Plumbing Code and allows AAV's. I want to do this job to code, not so much because I care about the code, but because doing so typically means its going to work as intended. (and I like the idea of a loop vent because there is no chance of sewer gas coming into the kitchen.)

Here's an improved schematic of what I'm thinking.

 

[JuanSigned]

It's done. I find these forums really helpful and I like to see it when others finish their projects, here's mine. After talking with a couple of local contractors and plumbers I went with an AAV in the end. Their consensus was don't be a fool about it, put in an AAV and be done with it. Getting the AAV to the require 4" above the trap arm also made a perfect place to put in a clean out. There's a little more slope than I'd like between the garbage disposal and the drain. The cool drain that came with the sink forces that connection down. If it becomes a problem I'll figure something else out.