Fire Safety Science最新文献

{"title":"Towards predictive simulation of wildfire spread at regional scale using ensemble-based data assimilation to correct the fire front position","authors":"M. Rochoux, C. Emery, S. Ricci, B. Cuenot, A. Trouvé","doi":"10.3801/iafss.fss.11-1443","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-1443","url":null,"abstract":"The objective of this study is to develop a prototype data-driven wildfire simulator capable of forecasting the fire spread dynamics. The prototype simulation capability features the following main components: a level-set-based fire propagation solver that adopts a regional scale viewpoint, treats wildfires as propagating fronts, and uses a description of the local rate of spread (ROS) of the fire as a function of vegetation properties and wind conditions based on Rothermel’s model; a series of observations of the fire front position; and a data assimilation algorithm based on an Ensemble Kalman Filter (EnKF). Members of the EnKF ensemble are generated through variations in estimates of the fire ignition location and/or variations in the ROS model parameters; the data assimilation algorithm also features a state estimation approach in which the estimation targets (the control variables) are the two-dimensional coordinates of the discretized fire front. The prototype simulation capability is first evaluated in a series of verification tests using syntheticallygenerated observations; the tests include representative cases with spatially-varying vegetation properties and temporally-varying wind conditions. The prototype simulation capability is then evaluated in a validation test corresponding to a controlled grassland fire experiment. The results indicate that data-driven simulations are capable of correcting inaccurate predictions of the fire front position and of subsequently providing an optimized forecast of the wildfire behavior.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"9 1","pages":"1443-1456"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89381751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Real Fire Test on Concrete Columns and Post-tensioned Slabs","authors":"I. Bennetts, W. South","doi":"10.3801/iafss.fss.11-558","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-558","url":null,"abstract":"An enclosure fire test was conducted incorporating high strength reinforced concrete columns and normal strength post-tensioned floor slabs. The slabs formed part of the roof whilst the columns within the enclosure were unloaded except for compressive stresses induced by the prestressing bar located at the centre of each of the columns. The columns and slabs were made from commonly available but markedly different Australian aggregates. Some of the columns incorporated 6mm monofilament polypropylene (pp) fibres introduced into the concrete mix at a concentration of 1kg per m 3 of concrete. With the exception of columns with pp fibres, spalling commenced within 10 minutes of the start of the test with all columns experiencing extreme spalling. The test was terminated at 68 minutes due to failure of one of the posttensioned slabs. Minimal spalling was obtained for slabs constructed from basaltic aggregate. The implications of the findings are considered with respect to the design of reinforced concrete structures.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"27 1","pages":"558-571"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78339734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A New Method for Quantifying Fire Growth Rates Using Statistical and Empirical Data – Applied to Determine the Effect of Arson","authors":"M. Nilsson, N. Johansson, P. Hees","doi":"10.3801/iafss.fss.11-517","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-517","url":null,"abstract":"When designing fire safety of buildings the fire growth rate is an important parameter, in large affecting the overall fire safety level within the building. Generally, a deterministic fire growth rate is used raising the question whether the resulting design arrives at a reasonable level of safety. A method was developed to obtain distributions of fire growth rates in specific building types. The new method uses data from two sources: fire statistics, and fire growth rates on single objects obtained by calorimetry experiments. In addition, the method was demonstrated by a case study investigating whether the overall fire growth rate is faster for commercial buildings if arson fires are included than if they are not. The results show that there is a considerably higher fire growth rate when arson fires are accounted for, e.g. designing for a fast fire growth rate of 0.047 kW/s2 covers 97% of accidental fires (arson excluded) but only 91% of all fires (arson included). The results indicate that there is a need to account for arson fires when designing buildings when the probability of arson is high. The developed method provides means to account for arson in fire safety engineering, and to further quantify the achieved fire safety level.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"16 1","pages":"517-530"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75122810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel Testing to Study the Performance of Intumescent Coatings under Non-Standard Heating Regimes","authors":"Angus Elliott, A. Temple, C. Maluk, L. Bisby","doi":"10.3801/IAFSS.FSS.11-652","DOIUrl":"https://doi.org/10.3801/IAFSS.FSS.11-652","url":null,"abstract":"Intumescent coatings (also called reactive coatings) are widely used to protect structural steel from fire. These thin coatings swell on heating to form a highly insulating char, protecting steel members and preventing them from reaching critical temperatures that could cause them to fail. As is the case for most structural materials and assemblies, intumescent coatings for use in buildings are typically developed and certified solely according to the standard cellulosic fire resistance test by exposure within a fire testing furnace. Reliance on furnace testing is expensive, non-representative of realistic fire conditions, and insufficiently versatile to gather detailed performance information on the response of reactive coatings under the full range of design fires which might be considered during a rational, performance-based design assessment. This paper presents a novel testing methodology for studying the performance of reactive coatings when subjected to non-standard heating regimes. The new approach is calibrated and validated using furnace test data, and is shown to offer considerable advantages over furnace testing in terms of reliability, repeatability, versatility, speed and cost. An investigation is then presented to study the effective variable thermal conductivity of a commercially available reactive coating when subjected to various timehistories of heat flux. It is shown that the heating rate and dry film thickness of the coating do not drastically affect the development of effective thermal conductivity with substrate temperature, leading to a proposal for a simplified method for specifying coating requirements and/or performing heat transfer design calculations when designing to non-standard heating regimes.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"3 1","pages":"652-665"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76256358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Model for Combustion of Firebrands of Various Shapes","authors":"H. Baum, A. Atreya","doi":"10.3801/IAFSS.FSS.11-1353","DOIUrl":"https://doi.org/10.3801/IAFSS.FSS.11-1353","url":null,"abstract":"The lifetime of a firebrand before burning out controls the maximum distance a firebrand can travel to cause spotting. Thus, combustion of firebrands of various shapes and sizes and their burnout time during transport is studied. The analysis assumes “quasi-steady” burning. In the present context, “quasi-steady” means that the rate processes controlling the gas phase fuel consumption and energy release are much faster than the particle fuel depletion time or the gas phase transport times. The Reynolds number based on the overall particle dimension and velocity relative to the ambient flow is assumed to be small. The gas phase combustion processes are represented by the evolution of a mixture fraction variable. It is shown that the velocity field near the particle can be described by a potential flow whose functional form is determined by the mass conservation equation and that this flow satisfies the particle surface boundary conditions. Gas phase solutions are obtained for two-parameter family of firebrand shapes composed of oblate and prolate ellipsoids of revolution. Prolate ellipsoids range from a thin needle to a sphere and oblate ellipsoids range from a sphere to a thin disc. Thus, they cover all possible firebrand shapes. The ambient velocity field does not need to be aligned with the firebrand axis of symmetry, so that the composite velocity and mixture fraction fields are three-dimensional. While a variety of steady-state condensed phase models are compatible with this picture, results are first presented for an ablating solid describable by the Spalding B number. B-numbers representative of flaming combustion of wood firebrands and glowing combustion of remaining char are used. All quantities are calculated as a function of ellipsoidal aspect ratio, B number, and the Reynolds number. Surprisingly, it is found that the firebrand burnout time is shape independent. All possible shapes were considered by using oblate and prolate ellipsoids of different sizes and aspect ratios. The burnout time depends only on the firebrand mass under the assumptions used.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"49 6 1","pages":"1353-1367"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76336550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fire protective performance of intumescent paint and ablative elastomer used for high pressure hydrogen composite cylinder","authors":"Dao D.-Q., T. Rogaume, J. Luche, F. Richard, L. B. Valencia, S. Ruban","doi":"10.3801/iafss.fss.11-794","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-794","url":null,"abstract":"The thermal degradation of epoxy resin/carbon fiber composites have been experimentally studied in ISO 5660 standard cone calorimeter. The influence of external heat fluxes on the reaction-to-fire properties of composite laminate is identified. Mass loss, time-to-ignition, specific mass loss rate, thermal response parameter and gasification heat were systematically measured and calculated. The four principal steps of the thermal degradation process of virgin composite are also analyzed and identified. In order to improve the reaction to fire of the composite for a safe hydrogen cylinder application, two insulating coatings (constituted by an intumescent paint or an ablative elastomer) have been applied on the exposure surface of composite. As a result, the thermal properties of composite (mass loss, time-to-ignition, SMLR peak amplitude and temperature at coating/composite interface) are improved significantly. Furthermore, the ablative elastomer represents a better fire protective performance than the intumescent paint one at low temperature. However, at high temperature conditions, the ablative layer is thermally broken and flaked away from the composite substrate, and so loses its protective performance. At low heat flux the intumescent paint shows slightly worse protective performance which becomes better than the ablative material at high heat flux conditions due to its very good bonding capacity to the composite surface.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"4 1","pages":"794-807"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73408975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prediction of Toxic Emissions from Chemical Fire and Explosion","authors":"N. Moussa, V. Devarakonda","doi":"10.3801/iafss.fss.11-1457","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-1457","url":null,"abstract":"The prediction of toxic emissions from industrial and warehouse fires and explosions involving reactive chemicals has eluded the hazard analysis community for quite some time. To address this issue, we developed a model called ADORA for the time evolution of toxic emissions and their dispersion in the atmosphere. At each time step, the conservation of mass, energy and momentum are solved while invoking thermochemical equilibrium or a constrained version thereof to determine the species composition in the cloud. During the initial stages of cloud evolution, the temperatures are usually high and thermochemical equilibrium applies. As the cloud cools down later due to air entrainment, the composition is governed by reaction kinetics. We use a computationally efficient approach called “constrained equilibrium” which is essentially an approximate way of accounting for temperature dependent reaction kinetics. In this approach, as air and moisture are entrained into the plume, the species concentrations are updated until the temperature decreases sufficiently to “freeze out” the toxic species of concern. The freeze-out temperatures for the toxic species of greatest concern are determined by examining the temperature dependent reaction kinetic rates. The temperatures below which the kinetics are too slow relative to cloud dynamics are selected as freeze out temperatures. This approach allows us to calculate as a function of time the cloud combustion rate, temperature, species composition, size, rise and travel distance downwind from the release location. Sample calculations for the detonation of explosives and for fires involving several reactive chemicals are given. For the former, the model predictions of major species such as carbon dioxide, carbon monoxide, nitrogen oxides and total non-methane hydrocarbons agree well with the limited available data. The model predicts the time dependent consumption of reactants and formation of reaction intermediates as well as stable end products. The concentration contours for toxic species such as hydrogen fluoride are presented and the trends discussed. The predictions of our model can be used to improve preparedness and emergency response planning in order to minimize the consequences of accidents involving reactive and energetic materials.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"22 1","pages":"1457-1468"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79173468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research Analysis of The Realistic Evacuation Behaviour from Tsunami and Fire in the aftermath of The Great East Japan Earthquake 2011","authors":"Y. Akizuki, A. Hokugo, Tomoaki Nishino","doi":"10.3801/iafss.fss.11-718","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-718","url":null,"abstract":"On March 11, 2011, a devastating tsunami caused by the Great East Japan Earthquake hit many towns in Tohoku area, and a lot of residents had to evacuate from tsunami and ensuing fire. Collecting and comprehending their evacuation behavior is crucial to provide useful information for future major earthquakes.. In this report, some actual track maps of escape routes from tsunami and fire based on our interviews are shown, and the characteristic of the realistic evacuation behavior is extracted. Moreover the large-scale surveys conducted by other institutions are summarized to justify our consideration.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"35 1","pages":"718-731"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80773297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revisiting the Compartment Fire","authors":"J. Torero, A. Majdalani, Cecilia Abecassis-Empis, Adam Cowlard","doi":"10.3801/IAFSS.FSS.11-28","DOIUrl":"https://doi.org/10.3801/IAFSS.FSS.11-28","url":null,"abstract":"Understanding the relevant behaviour of fire in buildings is critical for the continued provision of fire safety solutions as infrastructure continually evolves. Traditionally, new and improved understanding has helped define more accurate classifications and correspondingly, better prescriptive solutions. Among all the different concepts emerging from research into fire behaviour, the \"compartment fire\" is probably the one that has most influenced the evolution of the built environment. Initially, compartmentalization was exploited as a means of reducing the rate of fire spread in buildings. Through the observations acquired in fires, it was concluded that reducing spread rates enabled safe egress and a more effective intervention by the fire service. Thus, different forms of compartmentalization permeated through most prescriptive codes. Once fire behaviour within a compartment was conceptualized on the basis of scientific principles, the \"compartment fire\" framework became a means to establish, under certain specific circumstances, temperatures and thermal loads imposed by a fire to a building. This resulted not only in improved codes but also in a scientifically based methodology for the assessment of structural performance. The last three decades have however seen an evolution of the built environment away from compartmentalization while the \"compartment fire\" framework has remained. It is therefore necessary to revisit the knowledge underpinning this seminal approach to initiate discussion of its continued relevance and applicability to an increasingly non-compartmentalised built environment. This paper, through a review of classic literature and the description of some recent experimentation, aims to inform and encourage such discussion.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"68 1","pages":"28-45"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75581719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enclosure and Facade Fires: Physics and Applications","authors":"M. Delichatsios","doi":"10.3801/iafss.fss.11-3","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-3","url":null,"abstract":"Facade fires being a disastrous hazard for high rise building, as several historical and recent incidents have shown, have attracted the interests of numerous fire scientists, engineers and regulators. This work has as an objective to present issues in this area that are challenging and need further attention. It focuses on characterizing the flame height and heat fluxes from facade flames produced from under-ventilated enclosure fires on a facade that is not flammable. Such an investigation is an important consideration for practical applications as well as a prerequisite for examining fire spread on flammable facades and for designing a test for modern facade assemblies. The mass pyrolysis rates and burning of real fuels are discussed in under ventilated enclosures, rectangular or corridor like, for various openings presenting the current state and some critical issues. Facade flames are analyzed from experiments using gaseous burners to have control on the fuel supply rate by introducing physical length scales for the opening geometries to model flame heights and heat fluxes. An important parameter for the facade flames is the excess heat release rate of the fuel burning outside the enclosure. Finally, applications for facade flames with sidewalls and facade flames from two openings are presented.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"41 1","pages":"3-27"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72890228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}