The Ontario Building Code | Installation of Closures
3.1.8.5. installation of Closures
(1) Except where fire dampers, window assemblies and glass block are used as closures, closures of the same fire-protection rating installed on opposite sides of the same opening are deemed to have a fire-protection rating equal to the sum of the fire-protection ratings of the closures.
(2) Except as otherwise specified in this Part, every door, window assembly or glass block used as a closure in a required fire separation,
(a) shall be installed in conformance with nfpa 80, "Fire doors and Other opening Protectives", and
(b) where required to have a fire-protection rating, shall have labels or classification marks to identify the testing laboratory.
(3) If a door is installed so that it could damage the integrity of a fire separation if its swing is unrestricted, door stops shall be installed to prevent the damage.