| 1. |
- Audouin, L., et al.
(författare)
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Quantifying differences between computational results and measurements in the case of a large-scale well-confined fire scenario
- 2011
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Ingår i: Nuclear Engineering and Design. - : Elsevier BV. - 1872-759X .- 0029-5493. ; 241:1, s. 18-31
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this work was to quantify comparisons between several computational results and measurements performed during a pool fire scenario in a well-confined compartment. This collaborative work was initiated under the framework of the OECD fire research program and involves the most frequently used fire models in the fire community, including field and zone models. The experimental scenario was conducted at the French Institut de Radioprotection et de Surete Nucleaire (IRSN) and deals with a full-scale liquid pool fire in a confined and mechanically ventilated compartment representative for nuclear plants. The practical use of different metric operators and their ability to report the capabilities of fire models are presented. The quantitative comparisons between measurements and numerical results obtained from "open" calculations concern six important quantities from a safety viewpoint: gas temperature, oxygen concentration, wall temperature, total heat flux, compartment pressure and ventilation flow rate during the whole fire duration. The results indicate that it is important to use more than one metric for the validation process in order to get information on the uncertainties associated with different aspects of fire safety. (C) 2010 Elsevier B.V. All rights reserved.
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| 2. |
- Blomqvist, Per, et al.
(författare)
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Fires in storages of biofuels
- 2007
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Ingår i: Fire and Materials 2007 Proceedings.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 3. |
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| 4. |
- 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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| 5. |
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| 6. |
- Johansson, Nils, et al.
(författare)
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A Cost-Benefit Analysis of Fire Protection Systems Designed to Protect Against Exterior Arson Fires in Schools
- 2012
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Ingår i: 9th International Conference on Performance-Based Codes and Fire Safety Design Methods.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Fires in school buildings caused by arson are a major problem in Sweden. The costs of these fires are disproportionately high compared to the costs of fires in buildings in general, and it has been shown that fires that start outside of the building in connection with an exterior wall, so called exterior fires are especially problematic. However, technical systems can be used to mitigate the consequences of arson fires in school buildings. In this paper a cost-benefit analysis is used to calculate cost-benefit ratios for four technical systems used to detect these types of fires.
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| 7. |
- Johansson, Nils, et al.
(författare)
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Anlagd brand –Analys av kostnader och nyttor med tekniska system
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The project “Arson - a societal problem” has been running with funding from a number of players since 2008. The project consists of a number of sub-projects and the work presented in this report was conducted within the sub-project: "Technical- and risk-based methods to prevent and mitigate the consequences of arson". In this report a cost-benefit analysis of several different technical systems are performed on two reference buildings. The analysis shows that the technical systems are beneficial in areas where there is high risk of arson. However, none of the studied systems can be justified on a national level, because there are big differences between different schools and cities. For example there are differences in fire frequency and potential damage on a specific school.
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| 8. |
- Johansson, Nils, et al.
(författare)
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Behaviour of an intumescing system subjected to different heating conditions
- 2013
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Ingår i: Fire and Materials 2013 - 13th International Conference and Exhibition, Conference Proceedings. ; , s. 187-196
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Konferensbidrag (refereegranskat)abstract
- Previous studies have indicated that the expansion of fire seals and fire stoppers will be dependent on the heat exposure. Standardized methods for classification includes exposure to a rapid heat exposure of the product that is tested, but this might not always be the worst case scenario for the product. In this paper a series of tests are presented in order to study how a graphite based intumescing system, intended for cavities, reacts when subjected to fire conditions different form that in the standardised method EN 1366-4. Two different experimental setups, a cone calorimeter at Lund University and a small-scale furnace at SP Fire Technology, were used in the tests. The start of expansion reaction in the tested fire stopper was around 180°C. The start of reaction temperature is rather independent of the incident heat flux, while expansion rate is clearly dependent on the incident heat flux. Furthermore, the studied fire stopper performed well in the small-scale furnace because the graphite expanded enough to give the same protection, although it is preheated or wet, as when subjected to a heat exposure similar to ISO 834. These results are good but they are only considered valid for the studied system and for the given situation. Future research is needed in order to study how other types of intumescing fire protection systems work when subjected to realistic fire environments.
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| 9. |
- Johansson, Nils, et al.
(författare)
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Combining Statistics and Case Studies to Identify and Understand Deficiencies in Fire Protection
- 2012
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Ingår i: Fire Technology. - : Springer Science and Business Media LLC. - 0015-2684 .- 1572-8099. ; 48:4, s. 945-960
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Tidskriftsartikel (refereegranskat)abstract
- Over the years, much information has been gathered about fires in fire investigation reports and statistics. This information may have been collected nationally by an agency or an insurance company, or locally by the local rescue service. The information thus gathered can be used to learn from these fires and thereby lead to improved fire safety in buildings. This paper describes a method for discovering technical deficiencies in the fire safety of buildings. The method offers a means of analysing several fires systematically with the aim of identifying factors characteristic of a problem in the system studied. In this paper, the method is illustrated through a study of severe fires in school buildings in Sweden. The aim is to discover the underlying factors that cause some fires to grow and become severe. The method is considered a useful tool for discovering the underlying factors to or causes of fires.
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| 10. |
- Johansson, Nils, et al.
(författare)
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Detection of a typical arson fire scenario – comparison between experiments and simulations
- 2012
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Ingår i: Journal of Fire Protection Engineering. - : SAGE Publications. - 1042-3915 .- 1532-172X. ; 22:1, s. 23-44
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedBetween one and two school fires occur in Sweden every day. In most cases, arson is the cause of the fire. The most severe fires generally start outside the building and spread up along the façade and into the attic through ventilation openings in the eaves. Linear heat detectors can be placed on façades to detect these types of fires. Such devices detect fire when short-circuited at a specific temperature. In this article, an attempt to simulate linear heat detectors is presented. Data from small-scale and full-scale experiments are compared with these simulations. The small-scale experiments and simulations demonstrate that the cable failure model in Fire Dynamics Simulator can be used to predict detection in linear heat detectors that use short-circuiting as the means of signaling an overheated condition. The full-scale experiments provide a measure of the uncertainties involved, as well as the possibility of using simulations of linear heat detectors in a fire engineering design.
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