The Ontario Building Code | Adjustable Dampers and Balance Stops
6.2.4.6. Adjustable Dampers and Balance Stops
(1) All branch supply ducts for residential systems shall be equipped with volume control dampers at the boot to permit balancing or shall be fitted with a diffuser incorporating an adjustable and lockable volume control device that can be set in a fixed position.
In Plain Language
All branch supply ducts for residential systems must be equipped with volume control dampers, allowing the system to be balanced so each room receives an appropriate share of conditioned air.
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.