The Ontario Building Code | Rating of Firewalls
220.127.116.11. Rating of Firewalls
(1) A firewall that separates a building or buildings with floor areas containing a Group E or a Group F, Division 1 or 2 major occupancy shall be constructed as a fire separation of noncombustible construction having a fire-resistance ratingnot less than 4 h, except that where the upper portion of a firewall separates floor areascontaining other than Group E or Group F, Division 1 or 2 major occupancies, the fire-resistance rating of the upper portion of the firewall is permitted to be not less than 2 h.
(2) A firewall that separates a building or buildings with floor areas containing major occupancies other than Group E or Group F, Division 1 or 2 shall be constructed as a fire separation of noncombustible construction having a fire-resistance rating not less than 2 h.
(3) Except as permitted by Sentence (4), the required fire-resistance rating of a firewall,except for closures, shall be provided by masonry or concrete.
(4) A firewall permitted to have a fire-resistance rating not more than 2 h need not be constructed of masonry or concrete provided,
(a) the assembly providing the fire-resistance rating is protected against damage that would compromise the integrity of the assembly,
(b) the design conforms to Article 18.104.22.168.,
(c) the level of performance of the firewall is not less than of masonry or concrete in the areas of,
(i) performance during fire conditions,
(ii) mechanical damage during the normal use of the building, and
(iii) resistance to damage from moisture,
(d) the firewallseparates buildings or buildingswith floor areas that do not contain,
(i) a Group B, Division 1 major occupancy, or
(ii) a Group B, Division 2 major occupancy, and
(e) the firewalldoes not separate a building regulated by the provisions of Subsection 3.2.6. or a buildingwithin the scope of Article 22.214.171.124A. or 126.96.36.199A. from another building unless the buildingson both sides of the firewall are sprinklered.