Burning Up: Fire Safety Barriers to Low Embodied Carbon Housing in the NBCC

Abstract

The National Building Code of Canada (NBCC) emerged in response to, and developed from, catastrophic conflagrations throughout history which demanded the need for consistent construction and fire safety standards for buildings across the country. While fire safety remains an essential consideration in the development of Canadian society, many Code requirements inadvertently prescribe construction with high embodied carbon – emissions arising from the production, maintenance, and disposal of building materials – failing to recognize climate change as an existential threat. This thesis identifies, quantifies, and proposes alternatives to fire safety regulations within Part 3 of the NBCC that impede the design of low embodied carbon housing, particularly in missing middle and mid-rise typologies. While removing these regulatory barriers will not directly reduce embodied carbon, it enables future construction to have lower embodied carbon emissions which is critical to addressing Canada’s ongoing climate and housing crises.

Significant emissions reductions must occur in order to keep global temperatures from rising above +2°C and avoid climate catastrophe. Embodied carbon contributes approximately 13% of Canadian emissions and is essential to address, especially as operational carbon decreases with decarbonized energy and greater insulation. Missing middle and mid-rise housing offer the opportunity to provide low embodied carbon housing, however current NBCC regulations inhibit these benefits by prescribing urban, formal, and material requirements that are more restrictive than necessary.

The contemporary version of the NBCC is the result of continuous incremental development which reflects historical perspectives, scientific research, shifting social values, and arbitrary adjustments that can trace its roots back to the London fire of 1087. Construction materials, fire detection and suppression, and occupant behaviour have shifted significantly since the underlying structure of the building code was written. This work analyzes the Code as not only a technical document, but also as a historical and political artifact, emphasizing the importance of reconsidering regulatory assumptions in light of current fire safety and climate goals. Critically, the Code must explicitly include embodied carbon as one of its objectives.

Part 3 of the NBCC, which governs fire protection, accessibility, and safety, holds the potential to significantly reduce embodied carbon both through the amelioration of its explicit barriers, and through its influence on holistic design decisions. Seven barriers to low carbon housing at the urban, building, and material scale are identified through literature and expert interviews. Furter, their impact on fire safety and embodied carbon is analyzed, resulting in proposed changes which range from specific Code amendments to broad directions for future development.

The findings demonstrate that there are significant opportunities to align NBCC regulations with low embodied carbon goals without compromising fire safety. While the list of barriers investigated is inexhaustive, the breadth serves to illustrate the persistent manner that the Code specifies high embodied carbon while defining which changes are most impactful in emissions reduction. They provide starting points for more focused research and offer a framework through which to critically evaluate the Code. The work encourages architects and associated professionals to view the NBCC as a malleable document and advocates for greater involvement in future editions. Further, this thesis makes a unique contribution by identifying the relationship between fire safety and embodied carbon and by addressing their potential interactions through quantifiable metrics.