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In two recent papers [1, 2] the fire dynamics in a test rig for façade constructions according to the test method SP Brand 105 [3, 4] was investigated both experimentally and numerically. The experimental setup simulates a three-story apartment building (height 6.7 m, width 4 m and depth 1.6 m), with external wall-cladding and a “room fire” at the base. The numerical model was developed in the CFD program Fire Dynamics Simulator (FDS) [5] with analogous geometry and instrumentation. The general features of the fire test were well reproduced in the numerical model however temperatures close to the fire source could not be properly accounted for in the model. In this paper the bi-directional probe measurements are elaborated on and the test used in Ref. [1] is revisited using different heat release rates in the numerical model. The velocity of the hot gases along the façade was well reproduced by the simulations although some deviations were found.

Fires outside school buildings caused by arson are a major problem in Sweden. The initial fire source can involve rubbish or other types of combustibles that can be found at or sometimes brought to the school. As the external fire develops the flames will extend along the façade. If the building is a one-story building, which is a common construction in Swedish school buildings, the fire can spread to the attic and further on to the rest of the building. A large research project was initiated in 2008 by the Swedish Fire Research Board in order to reduce the number and consequences of arson fires in school buildings. In this paper an evaluation of some technical systems that can be used to mitigate consequences of exterior fires is presented. The evaluation includes a literature review, experimental studies and a cost-benefit analysis. The study showed that some systems have clear cost-benefit advantages for the protection of school buildings in places where a high fire frequency can be expected.