The development of this primer commenced shortly after the 2018 launch of the Mass Timber Institute (MTI) centered at the University of Toronto. Funding for this publication was generously provided by the Ontario Ministry of Natural Resources and Forestry. Although numerous jurisdictions have established design guides for tall mass timber buildings, architects and engineers often do not have access to the specialized building science knowledge required to deliver well performing mass timber buildings. MTI worked collaboratively with industry, design professionals, academia, researchers and code experts to develop the scope and content of this mass timber building science primer. Although provincially funded, the broader Canadian context underlying this publication was viewed as the most appropriate means of advancing Ontario’s nascent mass timber building industry. This publication also extends beyond Canada and is based on universally applicable principles of building science and how these principles may be used anywhere in all aspects of mass timber building technology. Specifically, these guidelines were developed to guide stakeholders in selecting and implementing appropriate building science practices and protocols to ensure the acceptable life cycle performance of mass timber buildings. It is essential that each representative stakeholder, developer/owner, architect/engineer, supplier, constructor, wood erector, building official, insurer, and facility manager, understand these principles and how to apply them during the design, procurement, construction and in-service phases before embarking on a mass timber building project.
When mass timber building technology has enjoyed the same degree of penetration as steel and concrete, this primer will be long outdated and its constituent concepts will have been baked into the training and education of design professionals and all those who fabricate, construct, maintain and manage mass timber buildings.
One of the most important reasons this publication was developed was to identify gaps in building science knowledge related to mass timber buildings and hopefully to address these gaps with appropriate research, development and demonstration programs. The mass timber building industry in Canada is still a collection of seedlings that continue to grow and as such they deserve the stewardship of the best available building science knowledge to sustain them until such time as they become a forest that can fend for itself.
This InfoNote summarizes recent research and work in progress. A significant amount of fire research has been conducted on mass timber over the last 10 years in Canada. This has supported the successful design and construction of numerous low-, mid-and even high-rise wood buildings. This has also fostered the introduction of new provisions into the National Building Code of Canada which has made wood and mass timber construction more accessible. However, the fire performance of these systems remains a concern for many potential occupants or owners of these buildings, not to mention building officials and fire departments. Research at FPInnovations continues to support designers and builders in the use of mass timber assemblies by ensuring fire safe designs.
This manual is helpful for experts and novices alike. Whether you’re new to mass timber
or an early adopter you’ll benefit from its comprehensive summary of the most up to date
resources on topics from mass timber products and applications to tall wood construction
The manual’s content includes WoodWorks technical papers, Think Wood continuing
education articles, case studies, expert Q&As, technical guides and other helpful tools.
Click through to view each individual resource or download the master resource folder for
all files in one handy location. For your convenience, this book will be updated annually as
mass timber product development and the market are quickly evolving.
The overall objective of this work is to expand options for designers of mass timber buildings by reducing the dependence on concrete and gypsum board though the demonstration of adequate fire performance of mass timber assemblies.
This work is intended to demonstrate that mass timber surfaces can be left exposed in concealed spaces, under certain conditions, while still performing well to control flame spread; this could result in significant savings in construction. Flame spread testing will be completed to compare the performance of mass timber assemblies and concealed space designs that are currently allowed by the NFPA 13 to be exempt from the installation ofsprinklers.
Data is needed to support the use of exposed mass timber in concealed spaces by demonstrating limited flame spread in concealed mass timber void spaces. Flame spread testing has already shown that mass timber has lower flame spread ratings than typically found with thinner wood panels. This will lead the way in allowing unsprinklered 305 mm (12 in.) deep concealed spaces beneath mass timber assemblies or exposed mass timber in other concealed spaces such as hollow wood floor beams.
The goal is to generate data to support the use of exposed mass timber in concealed spaces. This data could be used in an Alternative Solution to gain approval for this type of design. Ultimately, this could lead to changing the NBCC to allow exposed mass timber in concealed spaces.
"This report presents the findings from a simulation parametric study to investigate the use of water mist systems for a residential compartment fire involving exposed mass timber structures. The fire and suppression models were first validated against experimental data obtained from the NRC fire tests that were conducted under the same project. Seventeen simulations were conducted using Fire Dynamic Simulator (FDS) software. The following parameters were investigated: effect of fuel arrangement and location on fire severity in exposed wood compartment, effect of different finishing on fire severity in compartment, fire and suppression in open space vs compartment, effectiveness of water mist systems in fire suppression in compartments with different finishing. The results show the effectiveness of the water mist system in suppressing the fire in exposed wood compartments where a high heat release is expected due to the high fuel load"--Executive summary, page iv.
"As an alternative option to conventional sprinkler system, water mist systems are considered for the protection of timber buildings because they use much less amounts of water compared to sprinkler systems. The effectiveness of high pressure water mist (HPWM) and low pressure water mist (LPWM) systems was investigated in comparison to sprinkler systems for a residential fire scenario involving mass timber structures. The most distinct characteristic of the HPWM and LPWM systems was fine water droplets generated from the nozzles, which demonstrated effective smoke cooling in the room. Although the water spray rate of the HPWM was four times lower than that of the sprinkler system, the water mist systems effectively control the fire and maintained the room tenable. Most systems (HPWM, LPWM and sprinklers) tested in this study did not prevent fire damage on the CLT walls, but the HPWM system with a wide spray angle demonstrated rapid fire suppression and protection of the CLT walls. In all tests, a large water pool formed on the floor, which appeared proportional to the total water spray discharge in each test, and the moisture contents measured on the surface and bottom edges of the CLT panels indicated that water can penetrate into the interface between the floor and the wall in a typical CLT assembly"--Executive summary, page 1.
This project assesses the fire resistance of laminated timber structural systems as wall and floor assemblies. Full-scale tests were conducted to assess structural fire resistance and charring behaviour. This research could be used to expand current fire design provisions and support inclusion of these types of assemblies into Annex B of CSA O86.
The intent of this project is to research evaluation and rehabilitation methods that are applicable to mass timber structures following a fire. This includes addressing both fire damage and water damage from sprinkler activation and/or the use of firefighting hoses. This report provides an overview of the type of damage that might be expected following a fire and methods that might reduce potential damage (including design elements and firefighting tactics). Current and existing rehabilitation methods for wood construction will be reviewed and their applicability to mass timber structures will be discussed. This includes the ability to conduct condition assessments and repairs on building elements that can be done in place. The overall objective is to reduce uncertainty related to mass timber construction, which ultimately would allow for more accurate risk evaluation by insurance companies.
These Joint Professional Practice Guidelines – Encapsulated Mass Timber Construction Up to 12 Storeys were jointly prepared by the Architectural Institute of British Columbia (AIBC) and Engineers and Geoscientists British Columbia.
The AIBC and Engineers and Geoscientists BC regulate and govern the professions of architecture, engineering, and geoscience under the Architects Act and the Professional Governance Act. The AIBC and Engineers and Geoscientists BC each have a regulatory mandate to protect the public interest, which is met in part by setting and maintaining appropriate academic, experience, and professional practice standards.
Engineering Professionals are required per Section 7.3.1 of the Bylaws - Professional Governance Act to have regard for applicable standards, policies, plans, and practices established by the government or by Engineers and Geoscientists BC, including professional practice guidelines. For Engineering Professionals, these professional practice guidelines clarify the expectations for professional practice, conduct, and competence when providing engineering services for EMTC buildings. For Architects, these guidelines provide important information and identify issues to be considered when providing architectural services for EMTC buildings. These guidelines deal with the performance of specific activities in a manner such that Architects and Engineering Professionals can meet their professional obligations under the Architects Act and the Professional Governance Act.
These guidelines were developed in response to new classifications of building size and construction relative to occupancy introduced in the 2018 British Columbia Building Code (BCBC), under Division B, Article 22.214.171.124EMTC. Group C, up to 12 storeys, Sprinklered, and Article 126.96.36.199EMTC. Group D, up to 12 storeys, Sprinklered. These new classifications were introduced in Revision 2 of the 2018 BCBC on December 12, 2019 and in Amendment 12715 of the 2019 Vancouver Building By-law (VBBL) on July 1, 2020. Additionally, provisions related to Encapsulated Mass Timber Construction (EMTC) were introduced in Revision 1 of the 2018 British Columbia Fire Code (BCFC) on December 12, 2019.
These guidelines were first published in 2021 to provide guidance on architectural and engineering considerations relating to these significant changes to the 2018 BCBC, the 2019 VBBL, and the 2018 BCFC. For Engineering Professionals, these guidelines are intended to clarify the expectations of professional practice, conduct, and competence when Engineering Professionals are engaged on an EMTC building. For Architects, these guidelines inform and support relevant competency standards of practice to be met when Architects are engaged on an EMTC building.
As with all building and construction types, the EMTC-specific code provisions prescribe minimum requirements that must be met. The majority of EMTC of 7 to 12 storeys are considered High Buildings, and as such are subject to the BCBC, Subsection 3.2.6. Additional Requirements for High Buildings.
The costs of mass timber may be higher, but the added premium on their prices make them economically feasible. Beyond the economics, mass timber structures present a unique opportunity to develop and test the resiliency of the owner organization and its capacity to innovate. A collective effort to strengthen the supply chain in Ontario (especially the manufacturing stage) is one of the key tools to reduce costs. Having a dedicated fire consulting firm and the early engagement of regulatory bodies and consecrators are some of the key means to control risks in this domain. Earlier projects relied on covering/insulating mass timber sections to achieve the required fire requirements. Increasingly, charring is becoming an acceptable means for fire protection. Using Integrated Project Delivery system (IPD) and Building Information Modeling (BIM) can provide the contractual and technical platforms to boost coordination and promote collaborative design and construction.
The purpose of this guide is to provide an introduction to the concept of encapsulated mass timber construction. This guide provides an overview of encapsulation techniques for mass timber construction, and other related fire protection measures, and summarizes some approved encapsulation materials and application methods and identifies additional requirements for safety during construction. This guide is intended to help architects, engineers and designers by reducing uncertainty and allowing for more confidence in design, as well as providing authorities having jurisdiction and inspectors with a reference for simple design review.
The objective of this research is to evaluate CLT face-bonded with adhesives that meet the new 2018 ANSI/APA PRG 320 with respect to elevated temperature requirements and their effects on the resulting charring rates when exposed to the standard time-temperature curve of CAN/ULC S101 (similar exposure to ASTM E119)...
This report explores the building code related considerations of wood construction for school buildings that are up to four storeys in height. Though wood construction offers a viable structural material option for these buildings, the British Columbia Building Code (BCBC 2018) currently limits schools comprised of wood construction to a maximum of two storeys. Three- and four-storey schools and larger floor areas in wood construction require an Alternative Solution.
The report identifies key fire safety features offered by combustible construction materials including tested and currently widely available engineered mass timber products, such as glued-laminated timber and cross-laminated timber. A risk analysis identifies the risk areas defined by the objectives of the British Columbia Building Code (BCBC 2018) and evaluates the level of performance of the Building Code solutions for assembly occupancies vis-à-vis the level of performance offered by the proposed schools up to four storeys in building height.
As land values continue to rise, particularly in higher-density urban environments, schools with smaller footprints will become increasingly more necessary to satisfy enrollment demands. There are currently a number of planned new school projects throughout British Columbia that anticipate requiring either three-or four-storey buildings, and it is forecasted that the demand for school buildings of this size will continue to rise.
This report is closely related to the study Design Options for Three-and Four-Storey Wood School Buildings in British Columbia, which illustrates the range of possible timber construction approaches for school buildings that are up to four storeys in height.
Developed by ICC and American Wood Council, this first edition provides an overview of requirements for mass timber construction as found in the 2021 International Building Code® (IBC®). The document reviews the 2015 IBC’s recognition of cross-laminated timber (CLT), the reorganization of heavy timber provisions in the 2018 IBC, followed by the historic changes in the 2021 IBC and International Fire Code® (IFC®) for tall mass timber construction. The 2021 IBC and IFC include important changes in material technologies and their expanded use as proposed by the ICC Ad Hoc Committee on Tall Wood Buildings. Three new types of construction (Types IV-A, IV-B and IV-C) defined and included in the 2021 codes allow the use of mass timber for buildings of taller heights, more stories above grade, and greater allowable areas compared to existing provisions for heavy timber buildings.
More than 100 full-color photos, illustrations and tables enhance comprehension and help users visualize requirements
Content accurately reflects mass timber provisions in the 2015, 2018 and 2021 IBC, and 2021 IFC
“Change Significance” topics reinforce the content and offer helpful background regarding code provisions
Results are provided for five fire tests in a fully furnished structure constructed to simulate Types IV-A, IV-B and IV-C
Detailed examples facilitate comprehension of code application and methods of determining code compliance
Application of energy, sound transmission, structural loads, and other code provisions to mass timber construction
50 practice questions to help users prepare for ICC certification exams
This is an incredibly valuable and time-saving reference for architects, engineers, building/fire officials and inspectors.
Mass timber construction in Canada is in the spotlight and emerging as a sustainable building system that offers an opportunity to optimize the value of every tree harvested and to revitalize a declining forest industry, while providing climate mitigation solutions. Little research has been conducted, however, to identify the mass timber research priorities of end users, barriers to adoption and engineering, procurement and construction challenges in Canada. This study helps bridge these gaps. The study also created an interactive, three-dimensional GIS map displaying mass timber projects across North America, as an attempt to offer a helpful tool to practitioners, researchers and students, and fill a gap in existing knowledge sharing. The study findings, based on a web-based survey of mass timber end users, suggest the need for more research on (a) total project cost comparisons with concrete and steel, (b) hybrid systems and (c) mass timber building construction methods and guidelines. The most important barriers for successful adoption are (a) misconceptions about mass timber with respect to fire and building longevity, (b) high and uncertain insurance premiums, (c) higher cost of mass timber products compared to concrete and steel, and (d) resistance to changing from concrete and steel. In terms of challenges: (a) building code compliance and regulations, (b) design permits and approvals, and (c) insufficient design experts in the market are rated by study participants as the most pressing “engineering” challenge. The top procurement challenges are (a) too few manufactures and suppliers, (b) long distance transportation, and (c) supply and demand gaps. The most important construction challenges are (a) inadequate skilled workforce, (b) inadequate specialized subcontractors, and (c) excessive moisture exposure during construction.