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- Hjohlman, Maria, et al.
(författare)
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Design fire for a train compartment
- 2009
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Rapport (refereegranskat)abstract
- The fire dynamics of a train compartment was investigated in detail. A full scale test was performed which showed that the compartment reached flashover three minutes after ignition. Small scale tests were performed on the wall and floor linings and on seat and table materials. The results from these tests were used as input to a CFD-model implemented in FDS5 (Fire Dynamics Simulator, v5). It was possible to obtain a good correlation between the FDS5 model and the full scale experiment. However, in order to obtain this correlation it was necessary to deviate significantly from the small scale experimental results regarding the thermal conductivity of the seat material. Further, the FDS5 model was highly sensitive to grid size. Despite these drawbacks it was concluded that FDS5 can be used to determine design fires for the tested compartment and for geometries and material selections which do not differ drastically from the tested configuration. A much simpler way to obtain a design fire is to use so called t2 pre-flashover fires. Using this approach it was found that the growth rate of the compartment fire was between fast and ultra fast, with characteristic time scales of 150 s and 75 s, respectively. Finally it was concluded that the main part of the heat release originated from the seats and that a reasonable good design fire can be found by studying the fire dynamics of individual seats only.
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- Hjohlman, Maria, et al.
(författare)
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Flame Spread Modelling of Complex Textile Materials
- 2011
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Ingår i: Fire Technology. - : Springer Science and Business Media LLC. - 0015-2684 .- 1572-8099. ; 47:1, s. 85-106
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Tidskriftsartikel (refereegranskat)abstract
- Flame spread in textile materials was modelled using two different simulation programs: the semi-empirical area-based code ConeTools, and the computational fluid dynamics, CFD, code Fire Dynamics Simulator, FDS, (version 5). Two textile products developed within the EU-project Flexifunbar were selected for study. The two products show a large difference in composition and application area, one material is developed to function as a protecting layer for the underlying structure in case of fire while the other is an insulating material with no requirements on fire performance. The products represent materials for which fire test results indicate a classification on either end of the rating scale for wall materials according to EN 13501. Two FDS-models were developed for the simulations. The first FDS model was a relatively simple model of the small scale Cone Calorimeter test (ISO 5660) which served the purpose of a first preliminary validation of the model for pyrolysis of the material. In the second FDS model, a model of the intermediate scale Single Burning Item, SBI, test method (EN 13823), the fire scenario was expanded to simulate flame spread over a surface. The work included determination of the necessary material properties. In ConeTools, the option to predict an SBI test was used. The results from the two simulation methods were compared to real SBI tests. Neither model was able to fully predict the heat release rate for these complex products. However, the results from both codes were accurate enough to correctly predict the fire rating class for wall linings according to EN13501.
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