Using AAV in bathroom: help decyphering the code

Discussion in 'IPC Plumbing Code Questions' started by Michael M, Jan 8, 2018.

  1. Michael M

    Michael M New Member

    Jan 8, 2018
    Upstate New York
    I'm in the middle of re-modelling a bathroom, and trying to figure out what my venting options are. The original plumbing was definitely not up to any recent code.

    Specifically, I'm trying to figure out the part of the IPC that talks about "branch-type air admittance valves". The IPC has the following to say:

    Check! My fixtures are on the same floor level and connect to a horizontal branch.

    Here is where I'm confused. It sounds like I can put in a branch-type air admittance valve below floor level, as long as it's at least 4 inches above the horizontal branch drain. Is this correct? It seems odd to me that the code would require stack-type AAVs to be above the flood level rim of the highest vented fixture, individual-type AAVs to be above the fixture drain, but let horizontal branch AAVs be so low down. Am I misunderstanding something?
    Last edited: Jan 8, 2018
  2. ye4jim

    ye4jim New Member

    Mar 2, 2018
    Related question:

    Can a bathroom sink and shower share an AAV as shown? Note I forgot to show the p-trap for the shower, but it's there?

    How about if the shower was downstream of the sink ?


    Attached Files:

    Last edited: Mar 2, 2018
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