Findings from the Largest Mass Timber Fire Tests in Canada: Report

A recent report revealed the findings from Canada's mass timber demonstration fire tests project led by the Canadian Wood Council (CWC).

Image from: Canada Wood Council

The Canadian Wood Council (CWC) recently completed an extensive set of mass timber demonstration fire tests, which has resulted in the publication of a report entitled “Large-Scale Fire Tests of a Mass Timber Building Structure for MTDFTP (Mass Timber Demonstration Fire Test Program).”

This report, published by the National Research Council of Canada (NRC) on behalf of Natural Resources Canada (NRCan), presents the findings from a significant collaborative effort led by the CWC. This initiative involved various industry associations, federal and provincial government agencies, and fire safety and engineering consultants.

The primary objective of the Mass Timber Demonstration Fire Test Program was to assess the performance of mass timber construction when subjected to severe fire conditions. The overarching goal was to generate and disseminate crucial fire performance data to stakeholders in the construction sector and building and fire safety regulators. This information aims to support the acceptance of larger and taller mass timber buildings in Canada. Funding for this program was provided by NRCan, with the NRC offering technical support and conducting science-based fire tests as part of its commitment to advancing safe and innovative solutions within Canada’s construction industry.

As the leading authority on wood construction in the nation, the CWC expresses its satisfaction with the release of the NRC report. Robert Jonkman, P.Eng., Vice President of Codes and Engineering at CWC, emphasized the importance of the report’s findings. He stated, “We are very pleased with the report’s findings, which provide concrete evidence of mass timber’s exceptional structural fire performance. This scientific validation helps address concerns regarding its suitability for use in larger and taller building applications.”

The report presents the results of a series of five separate full-scale fire research experiments conducted by the NRC as part of the program during the summer of 2022. These experiments took place within a full-scale, 2-story, 334-square-meter mass timber structure located at NRCan’s Canadian Explosives Research Laboratory (CERL) in Ottawa. Notably, this represented the largest mass timber fire test conducted in Canada to date. Importantly, these fire tests were conducted without the presence of sprinklers or firefighting intervention for extended periods.

The findings revealed that even under severe, unsprinklered fire conditions with exposed structural mass timber, the test structure remained stable and structurally intact after enduring each of the five different fire tests, which varied in severity and duration. In total, the experiments exposed the structure to 19 hours of fire. These findings further bolster the CWC’s ongoing work in developing codes and standards, which will contribute to the establishment of evidence-based and regularly updated building codes that keep pace with innovations in construction technology.

This extensive project yielded valuable scientific data on various aspects of mass timber fire performance, including its behavior in open plan office settings, residential buildings, during construction, and the impact of exposed mass timber on fire severity and duration. Stakeholders can utilize this data and the resulting knowledge outcomes in several ways:

Firstly, it can aid in the design, evaluation, and approval of fire safety measures for tall and large mass timber buildings. Secondly, it can inform the development of firefighting strategies for both construction sites and finished buildings utilizing mass timber. Lastly, it can contribute to the development of relevant code changes related to mass timber construction.

The comprehensive research tests examined the fire performance of both exposed and encapsulated (gypsum board protected) mass timber in challenging fire scenarios. These valuable findings will serve as essential input when technical committees review code change proposals put forth by the CWC. These proposals seek to enable designers to leave a certain percentage of mass timber surfaces exposed in buildings designed with Encapsulated Mass Timber Construction (EMTC).

“This marks a significant milestone in the advancement of mass timber construction,” said Jonkman. “Apart from the evident benefits in terms of reduced construction schedules, environmental sustainability, and fire safety that project teams are already experiencing with EMTC construction, they will now have the added advantage of offering building occupants enhanced aesthetics. Moreover, the documented positive impacts on health and well-being, attributed to the incorporation of natural materials like exposed mass timber in indoor environments, will significantly enhance the overall benefits experienced by building occupants.”