Calder, Keith2025-09-222025-09-222025-09-222025-09-22https://hdl.handle.net/10012/22519The National Building Code of Canada (NBC) has traditionally applied a prescriptive-based framework to regulate fire and life safety in building design. While such a framework offers ease of enforcement, it limits innovative design. This framework transitioned in 2005 to be objective-based to provide greater design flexibility through clarity of intent, stopping short of a full shift to a performance-based framework due to concerns over challenges encountered by other jurisdictions during such transitions. 20 years later, the anticipated benefits of the shift to an objective-based framework have not been fully realized due to the lack of quantitative performance criteria and the reliance on primarily prescriptive and legacy-based acceptable solutions to define the acceptable level of performance for alternative designs. Key factors in the development of the NBC that have limited design flexibility and ultimately its shift from a prescriptive to a performance-based framework are the “test of time” and “absence-based inference” methods traditionally used to confirm performance. These factors, together with generational amnesia, status quo bias, shifting baselines of performance, and the limited integration of fire science and fire engineering, have resulted in fire safety design being governed primarily by the application of regulations rather than by fire safety engineering principles. As the NBC becomes further entrenched in tradition, the design flexibility required to address the evolving challenges of modern construction and emerging environmental risks becomes increasingly limited. To address these challenges, this thesis proposes a risk-based framework to facilitate the transition of the NBC from its current objective-based structure to a fully performance-based one. The proposed framework includes a historical analysis sub-framework to identify the rationale underlying the existing acceptable solution requirements, and a technical reconciliation sub-framework to align those requirements with current fire science and fire engineering principles, incorporating risk assessment methodologies to better quantify performance. It also includes a sub-framework, based on a modified IRCC hierarchy, that integrates the information identified and updated through the other sub-frameworks, establishing a clear and quantified link between the acceptable solutions and the societal objectives they are intended to achieve. By addressing factors in the development of the NBC that have limited its shift from prescriptive-based to performance-based, such as status quo bias, generational amnesia, shifting baselines of performance, and the limited integration of fire science and fire engineering, the proposed framework provides a structured approach that supports innovative design solutions while also achieving societal safety goals. The efficacy of this framework is demonstrated through detailed case studies that review acceptable solutions regulating office occupant load, exit width, building size and type of construction, and spatial separation. Historical analyses of these acceptable solutions identified the passive ventilation basis for the office occupant load factors, the influence of military experience on minimum exit widths, the limitation of building size to align with fire service capability, and the conservative nature of the spatial separation requirements due to limited test data, among other notable details. Given the outdated and nontechnical nature of these findings, recommendations were made for their modification through technical reconciliation with current test data, fire science, and fire engineering concepts. In particular, the finding that the flame front factor included in the spatial separation requirements may no longer be necessary is based on the results of a detailed risk-based analysis of incident radiant heat at a distance using an exterior venting flame model. The levels of the modified IRCC hierarchy were populated with information established from the historical analysis and updated through technical reconciliation for each case study, providing key basis information and quantified performance criteria within a risk-based structure that can be used to form a new and fully performance-based framework for the NBC. The results of this study are relevant to various stakeholders by supporting designers and building officials through clarification of intent and definition of measurable performance, and by providing building code development organizations with a tool for regulatory reform that enhances the clarity, consistency, and adaptability of the fire and life safety requirements in the NBC. The results also provide the technical basis information necessary to facilitate a transition in the practice of fire and life safety design from the strict application of prescriptive regulations toward an engineering-based approach. Additional research is recommended to evaluate the efficacy of the proposed framework through its application to other fire and life safety requirements in the NBC, to other aspects of the NBC, and to building codes in other jurisdictions. Further research should also focus on using the framework to quantify the technical risk basis necessary to support decision-making within a broader legal and regulatory context, thereby contributing to the continued advancement toward a performance-based NBC.enPerformance-basedFireBuilding CodeRiskDoctoral Thesis