Results of Fire Experiments to Quantify Residential Design Fires

Fire data on temporal combustion characteristics that define design fires, such as heat release rates, temperatures, radiant heat flux, smoke and composition of fire gases for different fire scenarios are indispensible in carrying out fire safety engineering analysis and design of buildings. This paper presents summarized results from a project that was conducted at the National Research Council of Canada (NRC) in order to characterize fires in multi-family residential dwellings and develop information for design fires. Such information is currently lacking for dwellings containing modern furnishings. Full-scale fire experiments were conducted in a specially constructed full-scale test facility. The test facility was instrumented to measure the heat release rate (HRR), heat flux, temperatures, gas velocities, smoke optical density and composition of fire gases at various locations. The test program involved an array of configurations to simulate key areas in a dwelling such as the bedroom, living room and main floor (with a kitchen and living room). Experiments were conducted for different floor areas and under various ventilation conditions. The fuel load consisted of typical residential furnishings. In all of the test scenarios, the first-ignited-item was a primary combustible furnishing, such as a bed assembly or an upholstered seat (sofa). The tests were designed to last for a period of 1 hr in order to capture the key phases of fire development: growth, flashover, fully-developed (post-flashover) and decay phases. In most of the tests, the fires developed rapidly and flashover occurred within approximately 3 min from ignition. The tests featured significant flame extension out of the openings, which was attributed to the rapid pyrolysis of the thermoplastic components of the fuel loads. The peak HRR values (for post-flashover fires) obtained in this test series varied from 2,790 kW to 9,230 kW (2,646Btu/s to 8.754 Btu/s), whereas the mean maximum temperatures varied from 1,040 degrees C (1,904 degrees F) to 1,200 degrees C (2,192 degrees F). The research addressed a range of issues concerning fire development in residential dwellings and provided an in-depth scientific analysis that could enable the fire safety community to tailor the results to meet various objectives taking into account the limitations of the tests.