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The Mass Timber Demonstration Fire Test Program (MTDFTP) included two series of experiments: the pilot scale demonstration tests in summer 2021 in Richmond, BC and the large scale fire tests in summer 2022 in Ottawa, ON. This report documents the series of large scale fire tests on a mass timber structure conducted to study fire safety during construction, fire dynamics and performance in an open plan office space and residential suites, as well as influence of exposed mass timber structural members on fire severity and duration.

In early 2018, with funding support from Natural Resources Canada and the Province of Ontario, the National Research Council of Canada conducted a series of room scale fire tests of Encapsulated Mass Timber Construction (EMTC). The goal of this test series is to further quantify the contribution of mass timber elements to fires and provide additional data for forming the technical basis for exposed mass timber elements in EMTC buildings without significantly increasing fire risks to life and property. The goal includes studying the fire performance of the 2nd generation cross-laminated timber (CLT) in resisting char layer fall-off, which could cause fire regrowth in the cooling phase of fully developed fires. The issues of char layer fall-off for the 1st generation CLT panels resulting in fire regrowth during the cooling phase of the fire were clearly revealed in the previous large scale CLT compartment fire tests under the auspices of the Fire Protection Research Foundation., A new version of the report was released on October 7, 2021, to correct an error in Section 2.1.2 of the original report published on August 8, 2018. To obtain a copy of the original report, contact NRC.DR-DN.CNRC@nrc-cnrc.gc.ca, Une nouvelle version du rapport a été publiée le 7 octobre 2021, afin de corriger une erreur dans la section 2.1.2 du rapport original publié le 8 août 2018. Afin d'obtenir une copie du rapport original, contactez NRC.DR-DN.CNRC@nrc-cnrc.gc.ca.

A series of 2-m pool fire experiments were performed to better evaluate the comparative thermal hazard between different crude oils as a result of pool fires, which could occur as a consequence of an accident in the land transport of crude oils. In order to assess the thermal conditions to which a rail tank car could be exposed, a calorimeter designed to simulate a 1/10th scale tank car was placed above a 2-m diameter pool fire fueled by heptane in Series 1 tests, Bakken crude oil from North Dakota in Series 2 tests and diluted bitumen (dilbit) crude oil from Alberta in Series 3 tests. The calorimeter was instrumented to measure the total heat flux at various locations along its surface. The crude oils used in the testing program were specially handled to ensure no change in its composition over the course of the testing program, from the time of fuel acquisition to the time of fire testing. In conjunction with the fire testing, a fuel characterization study was conducted to enable the study of fire effects in relation to fuel properties. The burning behaviours of the fuels were observed by measuring the burning rate, flame height and heat release rate (HRR), the flame surface emissive powers (SEP) and the incident heat fluxes away from the fire. Overall, the Bakken crude oil and heptane fires displayed continuous steady burning throughout the test while the dilbit crude oil fires displayed unsteady burning behaviour, which was mainly caused by the fuel composition containing a larger fraction of heavy end hydrocarbons than the Bakken crude oil and heptane. The total heat flux measured by the calorimeter indicated that the measurements were uneven around the circumference of the calorimeter. The average heat flux to the calorimeter from the Bakken and dilbit crude oil fires was higher than that from the heptane fires although the measured HRRs of the Bakken and dilbit crude oil pool fires were less than those of the heptane pool fires. The main reason for the increased heating of the object in particular by the Bakken and dilbit crude oil fires is that the total heat flux to the object is mostly affected by radiative heat exposure from the flame, and the Bakken and dilbit crude oil fires have higher radiative heat fraction. The study also investigated the effects of test parameters on fire characteristics. These parameters include the effect of fuel types, the presence and placement of a calorimeter engulfed in the fire, fuel feed temperature, and allowing the fuel to burn down. The results indicate that there was no significant effect of “fuel supply temperature” and “fuel to burn down (i.e., non-continuous fuel feed)”. The higher fuel supply temperature increased the burn rate by about 10% for the heptane and Bakken crude oil tests. For the dilbit crude oil fires, due to the non-steady burning behaviour, the impact of the calorimeter was difficult to capture. Allowing the fuel to burn down, rather than maintaining a constant fuel level in the pool pan, resulted in minimal effect on average values of the mass burning rate and general fire characteristics of the Bakken crude oil pool fires. For the dilbit crude oil, the fuel compositional effect on the burning behaviour was observed in both continuous and non-continuous fuel feeding. The non-uniform burning behaviour became easier to discern when there was no continuous fuel feed into the fuel pan.

Une série d’expériences de feu en nappe de 2 m de diamètre a été réalisée afin de mieux évaluer le danger thermique comparatif entre différents pétroles bruts au cours de feux en nappe, qui pourraient se produire à la suite d’un accident dans le transport terrestre de pétroles bruts. Afin d’évaluer les conditions thermiques auxquelles un wagon-citerne pourrait être exposé, un calorimètre conçu pour simuler un wagon-citerne à l’échelle 1/10e a été placé au-dessus d’un feu en nappe de 2 m de diamètre alimenté par de l’heptane dans les essais de la série 1, du pétrole brut de Bakken du Dakota du Nord dans les essais de la série 2 et du pétrole brut de bitume dilué (dilbit) de l’Alberta dans les essais de la série 3. Le calorimètre a été instrumenté pour mesurer le flux thermique total à différents endroits de sa surface. Les pétroles bruts utilisés dans le programme d’essai ont été spécialement manipulés pour garantir que leur composition ne change pas au cours du programme d’essai, depuis le moment de l’acquisition du combustible jusqu’au moment de l’essai au feu. Parallèlement aux essais au feu, une étude de caractérisation du combustible a été menée pour permettre l’étude des effets du feu en fonction des propriétés du combustible. Les comportements de combustion des combustibles ont été observés en mesurant le taux de combustion de la masse, la hauteur de la flamme et le débit thermique (DT), le pouvoir émissif de la flamme par unité de surface (PES) et les flux thermiques incidents à l’écart du feu. Dans l’ensemble, les feux d’heptane et de pétrole brut de Bakken ont montré une combustion continue et régulière tout au long de l’essai, tandis que les feux de dilbit ont montré un comportement de combustion instable, qui est principalement causé par la composition du combustible contenant une plus grande fraction d’hydrocarbures lourds que le pétrole brut de Bakken et l’heptane. Le flux thermique total mesuré par le calorimètre a indiqué que les mesures étaient inégales autour de la circonférence du calorimètre. Le flux thermique moyen vers le calorimètre provenant des feux de pétrole brut de Bakken et dilbit était plus élevé que celui des feux d’heptane, bien que les DT mesurés des feux en nappe de pétrole brut de Bakken et dilbit étaient inférieurs à ceux des feux en nappe d’heptane. La principale raison de l’échauffement accru de l’objet en particulier par les feux de pétrole brut de Bakken et dilbit est que le flux thermique total vers l’objet est principalement affecté par l’exposition à la chaleur par rayonnement de la flamme, et les feux de pétrole brut de Bakken et dilbit ont une fraction de chaleur par rayonnement plus élevée. L’étude a également porté sur les effets des paramètres d’essai sur les caractéristiques du feu. Ces paramètres comprennent l’effet des types de combustible, la présence et le placement d’un calorimètre dans le feu, la température du combustible d’alimentation et le fait de laisser le combustible se consumer. Les résultats indiquent qu’il n’y a pas eu d’effet significatif de la « température du combustible d’alimentation » et du fait de « laisser le combustible se consumer (c’est-à-dire une alimentation en combustible non continue) ». La température plus élevée du combustible d’alimentation a causé une augmentation de la vitesse de combustion d’environ 10 % pour les essais à l’heptane et au pétrole brut de Bakken. Pour les feux de pétrole brut dilbit, en raison du comportement de combustion non stable, l’impact du calorimètre a été difficile à saisir. Le fait de laisser le combustible se consumer, plutôt que de maintenir une profondeur de combustible constant dans le bac de la nappe, a eu un effet minimal sur les valeurs moyennes des taux de combustion de la masse de combustibleet les caractéristiques générales des feux en nappe de pétrole brut de Bakken. Pour le dilbit, l’effet de la composition du combustible sur le comportement au feu a été observé dans l’alimentation continue et non continue en combustible. Le comportement au feu non uniforme est devenu plus facile à discerner lorsqu’il n’y avait pas d’alimentation continue en combustible dans le réservoir., Supplements are only available in the English version of the report., Les suppléments ne sont disponibles que dans la version anglaise du rapport.

The Fire Protection Research Foundation (FPRF) initiated the project “Fire Safety Challenges of Tall Wood Buildings - Phase 2” to address the need for evaluating the contribution of mass timber elements to compartment fires. In part, this is linked to the concern that timber elements in tall wood buildings could increase the fire load, affect the fire growth rate, and potentially compromise fire protection systems in buildings, all of which could result in more severe conditions for occupants and responding fire fighters and increase the threat of damage to the property and adjacent properties. This project aimed to quantify the contribution of cross laminated timber (CLT) building elements to compartment fires, and to characterize the fire protection of the CLT structural elements using physical barrier (e.g., gypsum board) for delaying or preventing their involvement in the fire.

This study investigates the contribution of cross laminated timber (CLT) building elements to compartment fires. Six compartments (9.1 m long × 4.6 m wide × 2.7 m high) were constructed using 175 mm thick 5‑ply CLT structural panels and fire tested using residential contents and furnishings to provide a fuel load density of 550 MJ/m2. The results show that gypsum board can delay or prevent the involvement of the CLT in the fire, and that the ventilation conditions and exposed surface area of the CLT play a decisive role in the outcome of the test. The results highlight the need to use heat-resistant adhesives in cross laminated timber to minimize delamination. Ej belagd 180910

Standard fire endurance tests were performed on a full-scale floor assembly and a full-scale wall assembly constructed with cross-laminated timber (CLT) as the main structural element. The full-scale floor assembly consisted of CLT panels encapsulated with fiberglass wool and a single layer of 15.9 mm thick Type X gypsum board on the exposed side and with two layers of 12.7 mm thick cement board on the unexposed side. The full-scale wall assembly was constructed from CLT panels encapsulated with two layers of 15.9 mm thick Type X gypsum board on both faces. Nine thermocouples were installed on the unexposed face of both assemblies to monitor the temperature rise throughout the test and nine deflection gauges were installed on each assembly to monitor deformations. The superimposed load applied on the floor assembly was 9.4 kN/m² and the load imposed on the wall assembly was 449 kN/m. The fire endurance period of the full-scale floor assembly was 128 minutes and that of the full-scale wall assembly 219 minutes. Both the full-scale floor assembly and the full-scale wall assembly failed structurally afterwards under the applied loading. No hose stream tests were carried out on the full-scale floor and wall assemblies.