The Ontario Building Code | Support for Underground Horizontal Piping
7.3.4.6. support for Underground Horizontal Piping
(1) Except as provided in Sentence (2), nominally horizontal piping that is underground shall be supported on a base that is firm and continuous under the whole of the pipe.
(2) Nominally horizontal piping installed underground that is not supported as described in Sentence (1) may be installed using hangers fixed to a foundation or structural slab provided that the hangers are capable of,
(a) keeping the pipe in alignment, and
(b) supporting the weight,
(i) of the pipe,
(ii) its contents, and
(iii) the fill over the pipe.
In Plain Language
Underground horizontal piping must be supported and bedded appropriately, since soil settling around buried pipe can create stress points if the pipe isn't properly cushioned.
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.