I am installing a small basement bar sink that will be used infrequently. I was considering using an air admittance valve after the trap instead of running a vent to the roof. The drain will go about 15 feet before entering the main drain stack just before it exists the basement. There will be two 90 degree turns along the run. What do you think of these valves? Is it a proper use? Do you suggest a particular brand?
Also what size drain pipe is best to use and what is the ideal drop to run for the drain pipe. Thanks for the help.