Cross laminated timber (CLT) is a new engineered wood product that has experienced rapid growth and market acceptance for residential and non-residential construction in western and central Europe. Potential exists for rapid market adoption in North America if manufacturing capacities are developed...
The consortium of Nordic Wood Structures, EBC and Yvan Blouin Architect are designing a 13- storey residential building using a mass timber structure. The project, named "Origine" is proposed to be located in the eco-neighbourhood of Pointe-aux- Lièvres in Quebec City and to start construction in spring 2015. The mass timber structure would be composed primarily of glue-laminated timber and crosslaminated timber (CLT). The cross-laminated timber consists of at least three orthogonally bonded layers of solid-sawn lumber that are laminated by gluing of longitudinal and transverse layers with structural adhesives to form a solid rectangular-shaped, straight and plane timber intended for floor, roof or wall applications. The National Research Council Canada (NRC) was requested to assist in the demonstration of an alternative solution to noncombustible construction as prescribed in the Québec Construction Code  and the National Building Code of Canada (NBCC) . Three series of fire tests were conducted at NRC to investigate: the fire endurance (fire resistance) of CLT floor and wall assemblies , the fire performance of a CLT exterior wall assembly , and the fire demonstration of a CLT stair/elevator shaft for the proposed building. This report provides the description and results of the fire demonstration for the CLT stair/elevator shaft. This fire demonstration was funded by the Government of Quebec’s Ministère des Forêts, de la Faune et des Parcs through FPInnovations.
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 fullscale floor and wall assemblies.
Recent architectural trends include the design and construction of increasingly tall buildings with structural components comprised of engineered wood referred to by names including; cross laminated timber (CLT), laminated veneer lumber (LVL), or glued laminated timber (Glulam). These buildings are cited for their advantages in sustainability resulting from the use of wood as a renewable construction material. Previous research has shown that timber elements contribute to the fuel load in buildings and can increase the initial fire growth rate – potentially overwhelming fire protection system and creating more severe conditions for occupants, emergency responders, and nearby properties.
The overarching goal of this project Fire Safety Challenges of Tall Wood Buildings Phase 2 (involving five tasks) is to quantify the contribution of CLT building elements (wall and/or floor-ceiling assemblies) in compartment fires and provide data to allow comparison of the performance of CLT systems against other building systems commonly used in tall buildings.
Working in collaboration with the Canadian Wood Council and FPInnovations and in partnership
with Natural Resources Canada and the governments of Ontario, Quebec and British Columbia,
the National Research Council conducted a comprehensive research project, Research
Consortium for Wood and Wood-Hybrid Mid-rise Buildings. This consortium project aimed to
develop technical information that could be used to support acceptable solutions that meet the
NBC’s objectives for fire safety, acoustics, and building envelope performance, in order to
facilitate the use of wood-based structural materials in mid-rise buildings.
The objectives of the Wood and Wood-Hybrid Midrise Buildings research project were to
develop performance data and technical solutions in the areas of fire safety, acoustics and
building envelope pertinent to the use of wood-based structural materials in mid-rise buildings,
i.e. to develop an alternative solution to meet the 2010 NBC requirements for non-combustible
construction for 5-6 storey (and taller) buildings.
This project was intended to address the immediate needs for technical
solutions for mid-rise wood buildings that do not compromise the minimum levels of safety and
performance required by the 2010 NBC in the areas of fire safety and fire protection, acoustics,
and building envelope performance.
This report describes a full-scale exterior wall fire test conducted on December 16, 2014 on a Nordic cross-laminated timber (CLT) wall system. The test was conducted in accordance with CAN/ULC-S134-13, Standard Method of Fire Test of Exterior Wall Assemblies. The test was conducted using the exterior wall fire test facility located in the Burn Hall of the NRC Fire Laboratory, Mississippi Mills, Ontario. The CLT wall system was assembled to represent a continuous solid wood wall covered by a water barrier membrane and insulation. The pilot burners were lit prior to the commencement of the test. Gas flow to the burners was manually adjusted to follow the prescribed heat input required by the standard.
A full-scale demonstration fire was conducted at National Research Council Canada (NRCC) to show that a 2-hr non-standard severe design fire in an apartment would have little or no effect on an adjacent elevator or stair shaft. The test was performed to support the approval of an alternative solution for a deemed-to-satisfy 2-hr noncombustible construction assembly, intended for the construction of a tall wood building in Quebec City (Canada). Throughout the duration of the fire no impact was observed in the CLT shaft: there was no evidence of temperature rise and no apparent smoke leakage. This suggests there was little to no effect of the design fire on the structure of the CLT shaft itself.