air admittance valve question

[davep]

Saw a question about this and I wanted to ask an added question.

I have a wet bar I'm installing in the basement. Actually I'm finishing the entire basement so there is no sheet rock up yet. My main problem is that I cannot easily get to the basement bath vent "stack" from the wet bar. However, I have enough room behind what will become a finished exterior wall where I plan on running my drain pipe over to one of the main drain stacks so that I could T off to a air admittance valve.

Was wondering whether one of the air admittance valves could be used behind a finished wall? I'm thinking not since fresh air would be rather lacking. Also, wondering what the code might be for these valves??

Ideas?

thanks much, dp

[imported_jdcableguy]

I'll let someone else answer the air admittance question. was curious that since you were running the drain could you install a loop vent since you are tying into the main stack and vent?

Loop vent is a vent that as you come out of your trap to your drain the vent would be plumbed out the top at the drain wye and arch up to the countertop area and then down and will run paralell with the drain

[davep]

Got part of my answer, I think. Sounds like it would be a VERY BAD idea to place an air admittance valve behind a finished wall as the gases would collect with no where to go???

So, what if I put a louvered wall vent to allow fresh room air into the space where the air admittance valve would be?

As for the loop vent, I don't understand. Is this similar to the air vent above a kitchen sink?

Also, why if I'm tying into one of the two "main stacks" in my house for the drain wouldn't that stack also act as the vent? Doesn't this stack drain down and vent up?

Bottom line is I have to find a way to vent the wet bar properly so it does the job and passes code. I will double-check everthing with the county before moving forward, but need to get my plan together.

[Wgoodrich]

If you are using an 1 1/4" sink drain then a maximum of 5' is allowed from the trap to the vent. The trap shall not exceed 24" from sink outlet.

If you are using 1 1/2" drain then a maximum of 6' is allwed from the trap to the vent. The trap again shall not exceed 24" from sink outlet.

An air admittance valve must have incoming air. This valve is not allowed concealed within a wall.

Air admittance valves must meet the distance maximum mentioned above for a vent and these valves must remain accessible for the life of that valve.

The air admittance valve must be installed a minimum of 4" above the horizontal branch drain or fixture drain being vented.

Hope this helps

Wg