The Ontario Building Code | Basements and Pits
3.3.6.9. basements and Pits
(1) A process plant intended as a location where Class I and Class II liquids are handled shall not contain a basement or a covered pit.
Section 3.4. Exits
3.4.1. General
In Plain Language
A process plant handling Class I and Class II liquids (which are especially volatile) can't include a basement or covered pit, since these low points can trap heavier-than-air flammable vapours and create an explosion risk.
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.