Theme 2 – Fire Safety

Despite substantial research into the fire safety design of timber structures—the reader may refer to the reviews by Gerard et al. (2013), Brandon et al. (2016), and Buchanan et al. (2014)—there is a pressing need for more research into specific aspects of fire performance of timber elements and structures, especially in support of the next-generation performance-based design of timber buildings. The overarching objective of the research in Theme 2 is to address the knowledge gaps and research needs by generating evidence-based data related to risk perception, definition and quantification of fire performance parameters for timber buildings, and developing technologies and performance guidelines for use in prescriptive and performance-based design. For the experimental work, the specialized fire testing facilities at four partner universities will be utilized: (1) the Fire Research Facility at the University of Waterloo; (2) the Fire Testing and Research Laboratory at Lakehead University; (3) the Fire Laboratory at York University; and (4) the Fire Safety Lab at Université Laval.

Project T2-1 Development of Advanced Fire Design Methodology

This project consists of 3 sub-projects to generate technical information required for the development of advanced design methods, such as performance-based design. All three sub-projects focus on generating much-needed new understanding, input data, and a suite of tools and models to support the research on next-generation risk-based evaluation of fire performance in timber structures.

Sub-project T2-1-A – Determination of a risk-based framework and performance parameters for fire safety design

PI: Elizabeth Weckman , University of Waterloo and John Gales, York University

HQP: Kathryn Chin

As building codes transition from prescriptive towards more performance-based approaches, risk-based design methods have gained increasing attraction (Meacham 2021, La Malva 2018). Previous work summarized by Meacham (2021) further outlines the need to define risk measures (individual, societal, hazard-specific or aggregated) to inform evidence-based regulatory baselines against which performance can be assessed. Defining performance parameters and defining more precisely the risk measures are the objectives of this sub-project. Key outcomes include Canadian based data, models and performance guidelines that incorporate best practices and techniques from around the world. Final results will be synthesized for use in prescriptive, performance and engineering design and future code applications. In tandem, additional HQP trainees will conduct research in the other two sub-projects.

Sub-project T2-1-B – Compartment fire dynamics in timber structures under differing ventilation

PI: Elizabeth Weckman , University of Waterloo and Christian Dagenais , Laval University

HQP: Kathryn Chin

Sub-project T2-1-C – Design fires and charring rates for mass timber analysis

PI: Elizabeth Weckman , University of Waterloo and Christian Dagenais , Laval University

HQP: TBD

Predicting charring rate in timber is key for fire safety design under structural loads, but is rather challenging for reasons stated above. While some models are available to estimate depth of char under exposure to standard fires, it is necessary to collect new data and build advanced models for charring rate as functions of time and fire exposure (Friquin 2011, Lineham et al. 2016) and link those to fire performance and associated damage states (Meacham et al. 2021). Key outcomes of this sub-project will be the data obtained and predictive tools developed as these do not currently exist and their development is critical for improved understanding of timber charring mechanisms that will be incorporated into performance-based assessment and optimization of timber design for different building configurations.

Project T2-2 Fire Protection and Design of Timber Connections and Members

This project will develop innovative procedures to insulate timber connections and members from heat generated during a fire, and associated design procedures. It consists of two sub-projects.

Sub-project T2-2-A – Fire performance of connections

PI: Sam Salem, LakeHead University

HQP: Izaz Ahmad

There is currently no recognized fire design method for timber connections in Canada, even though CSA O86 currently stipulates that a timber connection must be designed to have the same Fire Resistance Rating (FRR) as the timber members that it connects. From a fire perspective, connections in mass timber construction can be divided into two categories: (1) exposed and (2) concealed. This research will focus on developing fire protection details for modern mass timber connections that can achieve 2-h FRR. Research will include small- and larger-scale fire performance testing of existing (baseline) and candidate new connection options. This will be closely coupled with numerical modelling of the thermo- mechanical and structural behaviour of exposed and concealed fasteners for timber components under load during a fire event. In addition to fire protection details, another key outcome of the research will be design approaches for traditional and new timber connections that could be implemented in CSA O86.

Sub-project T2-2-B – Encapsulation of timber elements

PI: Hajiloo Hamzeh, Carleton University and Sam Salem, LakeHead University

HQP: Sanaz Ramziaraghi and Javad Tashakori

Next Generation Wood Construction Page 13 of 34 Chui, Y. H. (18138) The encapsulation approach in NBCC 2020 for MT elements seeks to limit the contribution of the elements to fire growth and intensity by maintaining the surface temperature of the mass timber below its ignition temperature (Ranger et al. 2020). Also, with the increasing demand for eco-materials, there is a need to revisit the non-combustibility requirement and investigate the potential for encapsulating with materials exhibiting low-combustibility. The outcomes of this sub-project are new test data, models and guidelines related to encapsulation as a fire protection method for system design in either a prescriptive or performance-based framework.

Project T2-3 – Fire Design of Prefabricated and Modular Buildings

PI: Hajiloo Hamzeh, Carleton University and Sam Salem, LakeHead University

HQP: TBD

The design and construction of prefabricated and modular buildings vary greatly across applications and typically do not follow the same principles as on-site construction. As such, detailing between components and modules needs to be carefully considered at the outset, vetted and then well-coordinated by design professionals so that the expected level of fire safety is ensured for the completed structure. The outcome of this project is appropriate details and associated design tools for fire safety design of prefabricated and modular wood buildings. This project will be conducted in collaboration with sub- project T4-1-C.