In Plain Language

This clause is a design requirement for plumbing piping systems. Whatever material or layout is used, the system has to include some way to absorb the piping's natural expansion and contraction from temperature changes or building movement, such as loop offsets, expansion joints, or flexible couplings, so joints and fittings aren't stressed to the point of failure over time.

Common Questions

Q: Why does plumbing piping need "expansion" allowances?
Pipe materials expand and contract with temperature changes, especially hot water lines, and with building movement. Without some accommodation for that movement, the repeated stress can crack joints or fittings over the years, causing leaks. That's why the code requires a means to absorb it.

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.