The Ontario Building Code | Air Admittance Valves
7.5.9.2. Air Admittance Valves
(1) Air admittance valves shall only be used to vent,
(a) fixtures inbuildings undergoing renovation, and
(b) installations where connection to a vent may not be practical.
(2) The air admittance valves shall be located,
(a) above the flood level rim of the fixture it serves,
(b) within the maximum developed length permitted for the vent,
(c) not less than 150 mm above insulationhttp://thehandyforce.com/insulation/" title ="Toronto home insulation">insulation materials, and
(d) installed in a location not subject to back pressure.
(3) Air admittance valves shall,
(a) only vent fixtureslocated on the same storey, and
(b) be connected to the horizontal fixture drain.
In Plain Language
Air admittance valves must conform to the referenced standard for this equipment, ensuring the valve reliably opens to admit air and closes to block sewer gas.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.