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: Keon Senez, 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: Jan Jakub Dabrowski (UWaterloo) and Antony Beaulieu
When timber is exposed during a developing fire, it can lead to ‘non-standard’ fire behaviour, including
higher heat release rates, potentially increased compartment gas temperatures, higher incident heat fluxes to structural elements, prolonged fire durations and smouldering phases (Schmid et al. 2018), and more severe external flaming (Hopkin et al. 2020). While some methods to account for added fuel load due to combustibility of the timber structure (La Malva 2018, Senez et al. 2012) exist, many knowledge gaps remain (Su et al. 2018). Thus, it is necessary to develop new understanding, input data, and a suite of tools to support informed design decision-making, adaptable and suited to the Canadian context. Experimental results will be used with numerical models to develop credible design fire exposures and new predictive tools for assessment of fire damage and appropriate protection strategies. There will be close collaboration with sub-project T3-2-D as both are related to HVAC design
Sub-project T2-1-C – Design fires and charring rates for mass timber analysis
PI: John Gales, York University and Christian Dagenais , Laval University
HQP: Ethan Philion, Adrian Lau
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.
Sub-project T2-1-D – Mass Timber Composite Floor Systems: Fire performance, residual capacity, and rehabilitation
PI: Daniel Lacroix , University of Waterloo
HQP: Herry Chen, TBD
This research investigates the fire performance and post-fire rehabilitation of mass timber composite (MTC) floor systems, which integrate cross-laminated timber (CLT) panels with glulam webs via shear connections. Despite their effectiveness as long-span floor systems, MTC floors face challenges related to fire exposure and residual capacity. The study will evaluate the impact of fire on these systems, including the effects on structural integrity and methods for rehabilitation, such as using glass-fiber reinforced polymers to replace charred wood. By improving understanding of fire performance and developing accurate design methods and rehabilitation techniques, this research aims to enhance the safety, durability, and sustainability of MTC systems, supporting their broader adoption and effective use in modern construction.
Sub-project T2-1-E – Quantifying the external flaming risk from mass timber compartments
PI: Vinny Gupta , University of Waterloo
HQP: Kyle Weir
This research aims to address the heightened fire safety risks associated with mass timber compartments by quantifying external flaming risks through openings such as windows. Traditional fire safety measures, including non-combustible barriers and models for flame geometry, fall short in the context of mass timber construction, which significantly increases fuel loading and heat release. The study will involve reduced-scale fire experiments and advanced diagnostics to measure external flame exposure and develop new analytical models. These models will aid in designing safer timber buildings by providing more accurate predictions of fire spread and heat impact, thus enhancing protection strategies and performance-based design solutions for timber structures.
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
PI: Alexander Salenikovich
HQP: Amir M. Verki, Amir Khalighi
HQP: Luc Girompaire, Javad Tashakori
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 Izaz Ahmad
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.
Sub-project T2-2-C – Post fire smoldering propensity of Canadian wood species
PI: Felix Wiesner, University of British Columbia,
HQP: Hanupriyan Selvaganapathi
This project focuses on understanding smoldering fires in mass timber compartments, which can persist after flames are extinguished and cause slow but significant structural damage. Smoldering, a localized oxidation of char, often occurs at joints and intersections and poses a risk in taller timber buildings where self-extinction is relied upon. By conducting bench (cone calorimeter) and micro-scale (TGA) fire tests, the study aims to elucidate the onset and severity of smoldering specific to Canadian wood species. The outcomes will enhance knowledge of smoldering behavior, contribute to safer performance-based design of timber buildings, and inform strategies to reduce smoldering risks, ultimately improving fire safety and optimizing timber products from Canadian forests.