19 184564 ALT

Project Description

Proposed: Alternative Solution - A 14-storey Academic Tower is proposed for the University of Toronto. Based on the height of the tower, the 2012 Ontario Building Code (OBC) requires the building to be of noncombustible construction. The building is proposed to be of mass timber construction. The following mitigating features are proposed to ensure that the Academic Tower design provides a level of performance equal to or greater than that provided by the acceptable solution in the OBC:1) Sprinkler system increased reliability: - Increase in hazard level used for design of sprinkler system, resulting in 50% greater water delivered, to increase the reliability that the system will control the fire. - Two connections to the city water main to increase the reliability of the water supply to the sprinkler system. - Secondary fire pump as back-up in case the fire pump fails or is inoperable due to maintenance. - Second riser supplying each floor to provide redundancy in the supply of water to the location of the fire.2) Smoke control: - Pressurization of exit stairs in event of fire, to prevent smoke from affecting evacuation or fire department access to the fire floor. - Pressurization of fire service elevator (Elevator 3) in event of fire to prevent smoke from affecting access to the upper floors of the tower.3) Fire Resistance and Encapsulation: - The glued-laminated timber (glulam) beams, columns and braces that make up the exit cores (exit stair shafts) will be encapsulated in three layers of 15.9-mm-thick Type X gypsum board, to ensure the structure and stair shafts will not be adversely affected in the event of a fire. This will result in a fire-resistance rating of 2 hours provided by the gypsum board alone, with the inherent fire resistance to levels from 2.8 hours to as much as 4.8 h, resulting in much greater performance than required by the OBC acceptable solution. - The roof assembly will have a 1-h fire-resistance rating to reduce the likelihood of fire spread via the roof assembly.

Permit Details