The Ontario Building Code | Group A, Division 4
3.2.2.35. Group A, Division 4
(1) Except as permitted by Sentences (2) and (3), a building classified as Group A, Division 4 shall be of noncombustible construction.
(2) Roof assemblies and supporting arches and columns are permitted to be of heavy timber construction.
(3) A building classified as Group A, Division 4 is permitted to be of combustible constructionprovided,
(a) the occupant load is less than 1 500, and
(b) the buildinghas a limiting distance not less than 6 m.
(4) Sprinklers shall be installed in all spaces below tiers of seats in a building classified as Group A, Division 4 if those spaces are used for occupancy.