The Ontario Building Code | Size of Chimney Flues

9.21.2.4. Size of Chimney Flues

(1) Except for chimneys serving fireplaces, the size of a chimney flue shall conform to the requirements of the solid fuel-burning applianceinstallation standard referenced in Sentence 6.2.1.4.(1) and Article 9.33.1.2.

(2) Where a chimney flue serves only one solid fuel-burning appliance, the flue area shall be at least equal to that of the flue pipeconnected to it.