Systems & CodeQuestion 55 of 110
An air admittance valve (AAV) is used to vent an island fixture. Which condition must be met for the AAV to be acceptable?
a.It may serve as the only vent for the building
b.It may be buried in the wall permanently
c.It must be located in a ventilated, accessible space and at least 4 in above the horizontal branch drain
d.It replaces the need for any trap
Explanation
An AAV must be installed in a ventilated, accessible location and rise at least 4 in above the horizontal branch drain it serves, and it can never be the sole vent for a building. It admits air to relieve negative pressure but seals against sewer gas escaping. At least one vent must still open to atmosphere for the overall system.
Law Reference: IPC §917.0Practice all 110 questions free — no signup required.
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