The Ontario Building Code | Vent Pipes for Manholes
7.5.7.6. vent pipes for Manholes
(1) The minimum size of a vent pipe that serves a manhole within a building shall be 2 in.
In Plain Language
Manholes in the drainage system need their own vent pipes under the conditions set out in this article, since a sealed manhole can otherwise trap 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.