The Ontario Building Code | Prevention of Smoke Circulation
3.2.4.13. Prevention of Smoke Circulation
(1) If a fire alarm system is installed, an air handling system shall be designed to prevent the circulation of smoke upon a signal from a duct-type smoke detector if the air handling system,
(a) serves more than 1 storey,
(b) serves more than one suite in a storey,
(c) serves more than one fire compartment required by Sentence 3.3.3.5.(2), or
Note: On July 1, 2017, Clause 3.2.4.13.(1)(c) of Division B of the Regulation is amended by striking out "Sentence 3.3.3.5.(2)" and substituting "Sentence 3.3.3.5.(2) or Sentence 3.3.4.11.(2)". (See: O. Reg. 139/17, s. 27)
(d) is not provided with fire dampers as permitted by Sentence 3.1.8.8.(8).
In Plain Language
This clause requires magnetic door holders on fire separation doors to release automatically upon fire alarm activation, so doors that are normally propped open for convenience close automatically to contain fire and smoke.
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.