(1)  The unobstructed openable ventilation area to the outdoors for rooms and spaces in a residential occupancy ventilated by natural means shall conform to Table 9.32.2.1.

(2)  Where a vestibule opens directly off a living or dining room within a dwelling unit, ventilation to the outdoors for such rooms may be through the vestibule

Article 9.32.2.1 Ontario Regulation 332/12 Building Code,   Information published by oncodes.ca for educational purposes only.