Code Library › Volume 1 › Section 3.1 — General
PART 3 — FIRE PROTECTION, OCCUPANT SAFETY AND ACCESSIBILITYUpdated for the 2024 Ontario Building Code

3.1.8.12.Twenty-Minute Closures

(1) A door assembly having a fire-protection rating not less than 20 min is permitted to be used as a closure in (a) a fire separation not required to have a fire-resistance rating more than 1 h, located between (i) a public corridor and a suite, (ii) a corridor and adjacent sleeping rooms, or (iii) a corridor and adjacent classrooms, offices and libraries in Group A, Division 2 major occupancies, or (b) a fire separation not required to have a fire-resistance rating more than 45 min, located in a building not more than 3 storeys in building height. (2) The requirements for noncombustible sills and combustible floor coverings in NFPA 80, “Standard for Fire Doors and Other Opening Protectives,” do not apply to a door described in Sentence (1). (3) A door described in Sentence (1) shall have clearances of not more than 6 mm at the bottom and not more than 3 mm at the sides and top. (4) In elementary and secondary schools, a door assembly conforming to Articles 9.10.13.2. and 9.10.13.3. is permitted to be used as a closure in a fire separation having a fire-resistance rating of 30 min.
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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.