The Ontario Building Code | Concealed Spaces above Fire Separations
9.10.9.10. Concealed Spaces above Fire Separations
(1) Except as provided in Sentence (2), a horizontal service spaceor other concealed space located above a required vertical fire separation shall be divided at the fire separation by an equivalent fire separation within the space.
(2) Where a horizontal service space or other concealed space is located above a required vertical fire separationother than a vertical shaft, such space need not be divided as required in Sentence (1) provided the construction between such space and the space below is constructed as a fire separation having a fire-resistance rating not less than that required for the vertical fire separation, except that where the vertical fire separation is not required to have a fire-resistance rating greater than 45 min, the fire-resistance rating of the ceiling is permitted to be reduced to 30 min.
In Plain Language
Concealed spaces above a fire separation, such as above a corridor ceiling, have specific requirements set out in this article addressing hidden fire and smoke spread paths.
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.