24 235605 ALT

Project Description

Alternative Solution:The current version of the OBC 2012 does not set out any supporting clauses for the calculation of CLT fire-rating. As such, AECOM had been asked by the City of Toronto Building Permit Department to submit an alternative solution permit. The use of CLT in a 1 hour rated assembly is now supported by language in NBCC 2020.NBCC 2020 D-2.11 discusses Mass Timber Elements and their fire resistive properties that have been adopted, based on research by the Canadian Wood Council (and other jurisdictions). D-2.11.4 makes reference to the use of Annex B from the CWC and CSA O86.19. Please note that D-2.11 referenced from NBCC 2020, specifically D-2.11.4, has also been adopted by OBC 2024 (see 2024 OBC Volume 2, Pages 42 to 43, 2.11.4 Method B for Mass timber Element.) The attachment "Alternative Solution Response - CLT Floor Fire Rating" forming part of this submission discusses D-2.11 and includes a fire-rating calculation done as per Annex B of CSA O86.19.

Permit Details