Kitchen Sink Plumbing Vent ?

[Fred M. Minix, Jr.]

Is a vent or air admittance valve required when a kitchen sink drain is connected to a four inch drain line? The builder says "no", but I thought every fixture required some kind of vent.

[Jack L. Gilleland]

You thought right! Although, an AAV would probably work here, it is usually required to have a 1.5" vent going back to the main vent stack.

[Jeffrey R. Pope]

Originally Posted by fminix

I thought every fixture required some kind of vent.

That is correct.

[Ben J. Gromicko]

This might help.

http://www.nachi.org/plumbingcoursereleased2008.htm

Jump to "Vent Section." I think that it's a good course, but I'm heavily biased.

[Fred M. Minix, Jr.]

Thanks to all for your quick replies.
The things that some builders say to justify poor workmanship never cease to amaze me.

[Brian A. MacNeish]

Originally Posted by fminix

Is a vent or air admittance valve required when a kitchen sink drain is connected to a four inch drain line? The builder says "no", but I thought every fixture required some kind of vent.

He's confused!! He's heard the term "wet vent" and thinks that what is the under the sink is one.......No! No! No!