AVV and vanity/ shower

[jpokerwinski]

I am using a AVV to vent a vanity sink and a shower.
1. What is the minimum height for the AVV?
2. is there any particular order for the sink/shower hook up in relations to AVV ? My plan is to connect the sink drain to the AVV, then from the lower part of the fixture (2") i will tie the shower drain into the 2 " line .
3. there is a vent that i will leave for the toilet but it is too far from the sink and shower, hence the AVV.
The sink/shower will parallel a joist to the outside wall then down and connect to the vertical stack via sanitary Tee


Does this look reasonable ?

 

[CT18]

There are allowable distances you are allowed to run depending on your code. the AAV should be above the flood level of the fixture it is serving, and accessible.

 

[jpokerwinski]

There are allowable distances you are allowed to run depending on your code. the AAV should be above the flood level of the fixture it is serving, and accessible.

Flood level meaning the sink overflow? And one AVV can serve the shower and the sink?

 

[Jamesplumbing06]

Flood level is considered top of rim of sink. Get aav about 6” above that and your good with that “code”. But your putting 2 places on 1 aav. Code allows so many “fixture count”. I dunno how much. But are you asking if it will work or you building to code? Yeah it will work. At worst you get a gurgle in sink while shower is running..... now for the code book thumpers. No it’s impossible book says no. Lol.

 

[Mikey]

In Washington (UPC 2015 + local mods), it would appear that the AAV needn't be 6" above the flood level for a vanity sink, but the shower might complicate things. Maybe use a 2nd AAV on the shower?

(Italics mine):

912.1: Individual and branch line plumbing vents shall be permitted to terminate with a connection to an air admittance valve (AAV) where conventional venting of the fixtures would be impractical or burdensome. AAV’s shall only vent fixtures that are on the same floor level and connect to a horizontal branch drain.
912.3: AAV’s shall be located a minimum of four (4) inches above the branch drain or trap arm being vented and a minimum of six (6) inches above any insulation material. The AAV shall be located within the maximum developed length permitted for the vent in accordance with Chapter 7, Table 7-5. AAV’s shall not be located in spaces utilized as a supply or return air plenum. AAV’s shall not be used for venting a sump or ejector pump without written approval of the manufacturer.
912.4: AAV’s shall be installed in accessible locations. The valve shall be located within a ventilated space that allows air to enter the valve, such as below a kitchen or bathroom cabinet. The AAV may be installed in a wall only if it is provided with a ventilated access panel and is approved for such installation by the manufacturer.

Some good discussions re AAVs, both pro and con, in the Reeves Journal; e.g., https://www.reevesjournal.com/articles/84614-the-case-for-air-admittance-valves-aavs