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Today’s modern society strives to build higher and more complex buildings due to the constant increase of urban population. Several high and complex buildings have been constructed during the last decades in various parts of the world. However, this trend is relatively new and unexplored in Sweden. Another architectural trend in the construction industry is to create large window areas. The latest development of glass façade systems has made this request possible. The two most famous examples regarding these trends in Sweden are Kista Science Tower in Stockholm and Turning Torso in Malmö. The trend and technique to build high-rise buildings with alternative façade material, like glass, is rapidly implemented in Sweden. The lack of regulations, requirements and testing regarding the combination of these trends are consequences that follow the fast development. The requirements of today regarding fire safety design, only demand performance based design for buildings higher than sixteen floors. The Eurocode is another legislation, which contributes to more detailed guidelines regarding performance based design, and will shortly be implemented in all the affiliated countries in the European Union. Therefore a mix of current legislation and the Eurocode will be used in this thesis. This report theoretically examines how the fire develops when the exterior walls consisting of glass in an enclosed room breaks, when the room is located in the higher parts of a high rise building. The intensity of the fire tends to depend on the size of the opening. To illustrate the development of the temperature in the room, a comparison will be made with the curve for the standardized fire, ISO 834. Some of the temperature-time curves will be investigated further, to see how the increase in temperature affects the concrete and its strength. Furthermore, the radiation to the opposite façade wall is considered by using the calculated flame temperature and FireWind. To conclude the results, the temperature time-curves are highly affected by the size of the opening. In comparison with the ISO 834-curve, all of the scenarios with openings larger than 2,6x2,5 m2 resulted in more rapid and higher temperature developments. SAFIR showed that the curves, which exceeded the ISO 834 curve, had a large impact on the strength of the concrete at 20-30 millimetres depth. It is therefore necessary to have this in mind when deciding the thickness of the coating for the reinforced concrete. To ensure the resistance of the building’s framework, the time limit should be greater than 90 minutes, since most of the fire scenarios lasted up to 100-160 minutes. The likelihood of fire spread due to radiation is very high according to the results from FireWind. All cases, except one, exceed the recommended radiation level. It is therefore important that the entire glass façade system meets the required integrity and isolation to decrease the likelihood of fire spread, both within and between the compartments in the building. Validerat; 20110119 (ysko) |
