Code Library › Volume 1 › Section 9.32 — Ventilation
PART 9 — HOUSING AND SMALL BUILDINGSUpdated for the 2024 Ontario Building Code

9.32.3.7.Supplemental Exhaust (See Note A-9.32.3.7.)

(1) Except as provided in Sentences (2) and (3), a supplemental exhaust fan with a rated capacity not less than 50 L/s shall be installed in each kitchen. (2) A supplemental exhaust fan is not required in a kitchen where the only exhaust air intake for the principal ventilation fan is located in that kitchen. (3) A supplemental exhaust fan is not required in a kitchen where the principal ventilation fan draws from that kitchen and other rooms, provided (a) the principal ventilation fan can be switched to a high exhaust rate equal to not less than 2.5 times the minimum normal operating exhaust capacity specified in Table 9.32.3.3., and (b) the high exhaust rate of the principal ventilation fan, as described in Clause (a), is activated by a manual switch in the kitchen labeled “KITCHEN EXHAUST.” (4) Where an exhaust air intake for the principal ventilation fan is not located in a bathroom or water-closet room, a supplemental exhaust fan with a rated capacity not less than 25 L/s shall be installed in that bathroom or water-closet room. (5) Where the intake for a supplemental exhaust fan other than a cooking appliance exhaust fan serving a cooktop is installed in a kitchen, it shall be installed in the ceiling or on the wall at not less than 2 m above the floor. (6) A supplemental exhaust fan required by this Article shall be controlled by a manual switch located in the room served by the fan. (7) Where a kitchen or bathroom is exempted from the requirement to install a supplemental exhaust fan by virtue of Sentence (2) or (3), the principal ventilation fan shall be controlled by a manual switch located in the kitchen or bathroom and wired in parallel with the manual switch required by Sentence 9.32.3.3.(5). (8) Where a supplemental exhaust fan required by this Article is controlled by a dehumidistat or other automatic control in addition to the manual switch required by Sentence (6), the manual switch shall be capable of activating the fan regardless of the setting of the automatic control.

This provision includes a table — formatting is preserved from the source; refer to the official code for the authoritative layout.

← Previous9.32.3.6. Exhaust-Only Ventilation Systems (See Note A-9.3Next →9.32.3.8. Protection Against Depressurization (See Note A-

Common questions about this part of the code

How is the principal ventilation fan sized by number of bedrooms in Ontario?What are the exhaust fan requirements for bathrooms and kitchens in Ontario?What are the minimum openable window areas for natural ventilation in Ontario?

Understand this provision in seconds

BUILDAiD Assist explains any article of the building code in plain English — with exact citations, exceptions and related requirements.

Try BUILDAiD Beta

Code text is reproduced for reference from the Ontario Building Code (O. Reg. 163/24, 2024 Building Code Compendium). This page is provided for general information and is not an official copy. Always verify requirements against the official Ontario Building Code and confirm with your local building department.