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.
In Plain Language
This article sets one of the specific size-and-construction packages available for a Group A, Division 4 (open-air assembly) buildings building: generally noncombustible construction, though heavy timber roofs/supports are allowed, and combustible construction is permitted if occupant load stays under 1,500 and limiting distance is at least 6 m; sprinklers are required under any tiered seating in active use. Designers can choose whichever of the several packages in this Subsection best fits the building being planned, trading height and area against construction type, sprinklering, and fire-resistance rating requirements.
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.