The Ontario Building Code | Hot Water Piping Insulation
12.3.1.4. Hot water Piping insulationhttp://thehandyforce.com/insulation/" title ="Toronto home insulation">insulation
(1) Hot water pipes that are vertically connected to a hot water storage tank shall have heat traps on both inlet and outlet piping as close as practical to the tank, except where the tank,
(a) has an integral heat trap, or
(b) serves a recirculating system.
(2) The first 2.5 m of hot water outlet piping of a hot water storage tank serving a non-recirculating system shall be insulated to provide a thermal resistance of not less than RSI 0.62.
(3) The inlet pipe of a hot water storage tank between the heat trap and the tank serving a non-recirculating system shall be insulated to provide a thermal resistance of not less than RSI 0.62.
In Plain Language
Hot water pipes vertically connected to a hot water storage tank need heat traps on both inlet and outlet piping, close to the tank, as set out in this article, unless the tank already has an integral heat trap, preventing wasteful heat loss through convection in the piping.
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.