Fire represents one of the significant hazards encountered by civil infrastructures, and thus providing appropriate fire safety measures is a major requirement in a building design for ensuring the safety of the occupants. Minimizing fire-induced damage and collapse of structural systems are the primary objectives in the design of concrete structures. An experimental investigation has been carried out to examine the mechanical properties such as compressive, tensile and flexural strengths of concrete exposed to elevated temperature following standard fire curve as per ISO 834. Capacity-based standards have been formulated to predict the residual strength of various grades of concrete exposed to various duration of heating. Stress strain behaviour, elastic modulus, weight loss, spalling and thermal crack pattern of specimens were also investigated. Water–cement ratio and porosity of concrete were found to be the critical factors for strength loss of concrete. A relationship is established between weight loss and strength loss of concrete. Higher grades of concrete were found to have more weight and strength loss than those of lower grades.

Cross-laminated-timber (CLT) panels are a type of relatively new wood-based structural panel, typically manufactured by laminating three or more layers of lumber together, with each layer rotated 90° relative to the neighbouring layers. This study explored preliminary assessment of the physical properties of a range of specimens for the purpose of initiating generating material property data for hygrothermal simulation of CLT building enclosure assemblies. Three types of five-layer CLT panels (nominally 130 mm thick) were made with Canadian softwood species, including spruce-pine-fir (SPF) from Eastern Canada and British Columbia, and hem fir from British Columbia, all glued with emulsion polymer isocyanate (EPI) as the adhesive applied between neighbouring layers. One type of three-layer CLT (nominally 90 mm thick) commercially manufactured in Europe using European spruce, with polyurethane adhesive, was also tested. Physical properties including density, thermal conductivity, liquid-water absorption, water-vapor permeability, sorption (moisture storage function), and air permeability were measured, mostly based on established international standards. To assess the impact of the adhesive on the hygrothermal properties of CLTs, test specimens used for most tests included at least one layer of adhesive, except those used for sorption tests, which used very small specimens. The properties were expected to mostly reflect the properties of the lumber used for CLT manufacturing. Variations in properties were found among these different CLT specimens; however, it was generally concluded that the differences caused by wood species and manufacturing methods would not be large enough to cause considerable differences in the hygrothermal properties or significantly impact the outcomes of hygrothermal simulation. With small-scale testing and very limited replication this study showed that the water-vapor permeability of CLT generally increased with an increase in relative humidity (RH), and the air permeance of the CLT specimens without visible gaps and checks was negligible.

Two series of experiments were conducted to determine the burning characteristics of different fuel packages, in both pre- and post-flashover fires, to develop data to characterize design fires for commercial premises. These fuel packages represented fuel loads determined from the survey of commercial buildings. Results suggest substantial differences in the burning characteristics of different stores. In this article, the description of the recommended design fires includes: (1) types of combustibles, (2) fire load density (MJ/m 2), (3) fire growth rate, and (4) yields of CO and CO2.

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SUMMARYThis paper presents the results of a survey conducted in the Canadian cities of Ottawa and Gatineau to characterize fire loads in commercial premises. The survey included various commercial establishments such as restaurants, travel agencies, and pharmacies, as well as, retail stores selling clothing, shoes, food, alcohol, computers, and computer supplies. Five different types of combustible material groups were selected as the base of analyses: textiles, plastics, wood/paper, food, and miscellaneous. The data collected were analyzed to determine the total fire load in each establishment, the fire load density, and the contribution of different combustible materials to the total fire load. A total of 168 commercial premises were surveyed with a total floor area of 17 127 m 2 . The area of the surveyed stores ranged from 3.25 to 1707 m 2 . The fire load densities of the 168 surveyed stores had a lognormal distribution with a mean value of 747 MJ/m 2 , a maximum value of 5305 MJ/m 2 , a minimum value of 56 MJ/m 2 , and a standard deviation of 833 MJ/m 2 . In most stores, the 95th percentile and the mean fire load density showed a tendency to decrease with an increase of floor area, which is consistent with those of earlier surveys.