The target audience for this technical resource includes building officials, fire service, architects, engineers, builders, code consultants and developers and other parties involved in the design and approvals of tall wood noted in Table 1 below. This technical resource is expected to help illustrate to applicants how tall wood buildings could be designed as alternative solutions in a way that achieves the level of performance required by Ontario’s Building Code.
A tall wood building is defined as a building over six-storeys that uses wood for its structural system and is built using mass timber construction. Mass timber refers to large dimension solid lumber, gluedlaminated lumber, cross-laminated lumber or other large dimension wood products referenced in this technical resource as opposed to conventional stick-frame construction typically used in low-rise and midrise buildings in Ontario. Mass timber offers the advantages of improved dimensional stability and better fire performance during construction and occupancy. Tall wood buildings are not new to Ontario – many such buildings are still in use in Ontario after nearly 100 years in service, however over time, changes to building codes and the introduction of steel and concrete for high-rise construction resulted in a decline in construction of tall wood buildings over the decades. But with new wood products and modern means of fire engineering, modern tall wood buildings are now being built in Canada. The new products and the way in which they are pre-fabricated and constructed offer tremendous opportunities to improve quality and speed of construction for buildings in Ontario.
Mass timber products have environmental advantages as well. Trees get their energy from the sun and absorb carbon from the atmosphere. As they grow, trees store carbon and by sustainably harvesting trees, the carbon is sequestered, which helps to reduce greenhouse gas. The carbon stored in wood is not released into the atmosphere when it is harvested. As new trees are planted to replace the harvested trees, the new trees will continue the cycle of carbon storage. Ontario and Canada have significant forest resources which, combined with sustainable forestry management practices, make tall wood buildings an attractive alternate to other materials which do not have these attributes. This technical resource has two main sections: Fire Safety and Structural Design.
These two major topics are normally of most concern during design and review of tall wood buildings and are at times interrelated. Thus, it is expected that design teams and building departments will work together at the early stages of design since structural decisions can affect fire performance and vice versa. The sections go into detail on aspects of compliance, methods of analysis, methods of design and the expected performance requirements for fire and structure. Other topics such as thermal performance, acoustic performance and constructability are covered in other references as noted throughout this technical resource.
