The Ontario Building Code | Copper Joints Used Underground
7.3.3.12. copper Joints Used Underground
(1) Except as provided in Sentence (2), joints in copper tubes installed underground shall be,
(a) made with either flared or compression fittings, or
(b) brazed using a brazing alloy within the American Welding Society’s AWS-BCuP range.
(2) Compression fittings shall not be used underground under a building.
7.3.4. support of Piping
In Plain Language
Except in one permitted case, joints in copper tube installed underground must meet specific requirements, since buried joints are harder to inspect or repair if they fail.
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.