Mark, with all due respect, I'm going to re-iterate my stance.
master plumber mark said:
Their is doing things the right way and then their is makeing a mountain out of a mole hill.
Since when is correctly venting a fixture during a "total kitchen remodel" making a mountain out of a mole hill? Since when are non-vented fixtures the "right way"? Since when is the "let sleeping dogs lie" mentality ok because it's too much like work to do it right; or to even let the asker consider what is approved from a code perspective v/s 'what you got has worked'.
this is not the space shuttle or a hospital, its a kitchen sink drain.---in a kitchen
Does not matter from a code perspective. Fixture is a fixture no matter where it is.
So why in the world would you want to find a way to make an island vent for something that would work fine for the next 50 years with a Auto air vent and p trap????
The island vent is listed by me as a code approved alternative to conventional venting methods. This brings me into your next statement:
They make those Auto Air vents and have been useing them for at least 25 years.....they are legal almost everywhere...because they work great.....
You imply that something that's been around for at least 25 years is going to become something that will last 50 years. AAV's have been used for over 25 years in trailer houses, per the very relaxed HUD and DOT codes which govern such dwellings.
Now I don't beat my drum, but I too am a master plumber in both Minnesota and North Dakota. Minnesota has a proprietary plumbing code which predates the UPC (1933), and North Dakota has an amended 2000 UPC. Neither code allows for AAV's.
Minnesota will allow an island vent (boston loop or as seen here:
https://terrylove.com/images/island_vent.gif ) if structural limitations prevent conventional venting methods. North Dakota will allow the boston loop, or the more common method of increasing the fixture branch sizing twice to 3", and venting the 3" within 15' of the fixture.
so why would you want to beat your braines out trying to
tear up a wall and install an isalnd vent and do something
that way...
especially when that drum trap did an ok job
for 100 years already??
Because I know better.
One thing that the AAV does not account for is backpressure. The AAV can only prevent backsiphonage, it cannot relieve the drain of any positive pressure that may exist due to upsteam fixtures discharging, downstream blockages or foaming from nearby suds producing fixtures. Additionally, up north where it gets cold, we are required to ventilate the city's sanitary sewer system through our DWV systems. Come on up here next time it's cold, I'll take you on a roof of any vacant building you choose. We can bask in the warm air that's coming up through the VTR's.
Perhaps the biggest issue as to why I find myself typing this, (rather than doing stuff that I might get benefit from) is we, as professional plumbers, have an obligation to
provide information that is codeworthy. Now, some may say that's overkill, but codes are nothing more than minimum standards. Doing something to code is not overkill, it is the bare minimum of what is needed to be found sufficient. We do have an obligation not only to our craft, but to the end user, to ensure that they have a system that is safe and requires minimal maintainance.
I, as a professional, shouldn't be in the buisness of circumventing minimum standards and neither should the rest. I treat my responses as if someone were paying me +$100/hr to do their work. I treat myself as a resource of information. If that information goes against the grain somestimes, so it goes. I don't find myself at the doctor asking for only the good news or what I want to hear.
Sorry for the schpiel, had to get that out.