The Ontario Building Code | Maximum Size of Opening
9.10.13.8. Maximum Size of opening
(1) The size of an opening in an interior fire separation, even where protected with a closure, shall not exceed 11 m², with no dimension greater than 3.7 m, if a fire compartment on either side of the fire separationis not sprinklered.
(2) The size of an opening in an interior fire separation, even where protected with a closure, shall not exceed 22 m², with no dimension greater than 6 m, when the fire compartments on both sides of the fire separation are sprinklered.