化工企业厂区消防给水系统探究

化工企业厂房的消防工作关系到国家财产和人民生命的安全,因此对于其消防给水的设计必须要严格按照规程办事,认真仔细不能有半点马虎。从大型化工厂区的消防给水、污水排放等系统的具体的布置以及安排要领出发,详细的介绍了给排水管道在材料的选择,基础的摆放以及附属建筑的设计等相关的内容。     

自动喷水灭火系统湿式报警阀组误报案例引发的思考

通过对一起自动喷水灭火系统湿式报警阀组误报案例的研究,分析了误报发生的原因,提出了防止误报应采取的措施,并对修改完善有关消防技术标准提出建议。     

某大型住宅小区火灾自动报警系统的电气设计

火灾自动报警系统已成为住宅小区设计中不可或缺的一部分,系统设计的优良与否直接关系到人民群众的生命财产安全。该文结合工作中的实际项目,对国内某大型高层住宅小区火灾自动报警系统的电气设计做了简要分析,总结了设计过程中应该注意的问题与事项。     

Hydrocarbon flame inhibition by C6F12O (Novec 1230): Unstretched burning velocity measurements and predictions

This study experimentally and numerically determined the unstretched laminar burning velocity of premixed CH₄-air and C₃H₈-air flames with added C₆F₁₂O (Novec 1230). High-speed shadowgraphy of spherically expanding flames provided the burning velocity as a function of stretch, which was extrapolated to zero-stretch conditions using non-linear methods. Unstretched burning velocities predicted using a recently assembled kinetic mechanism were generally in good agreement with the measurements, but tended to have poorer agreement for highly-inhibited very lean flames. To benchmark the performance of C₆F₁₂O, measured burning velocities were compared to previously measured burning velocities of premixed flames inhibited by CF₃Br (Halon 1301). The two agents provided similar reductions in the burning velocity of rich flames, whereas CF₃Br provided greater reductions when added to stoichiometric and lean flames. Lastly, experiments and simulations showed the influence of water vapor on the burning velocity of lean C₃H₈-air flames with added C₆F₁₂O. The presence of water vapor in the oxidizer increased the burning velocity by up to 23% when the fluorine to hydrogen ratio of the reactant mixture was greater than unity.     

Combustion enhancement and inhibition of hydrogen-doped methane flame by HFC-227ea

Hydrogen enriched with compressed natural gas is an efficient and environment-friendly gaseous fuel. However, the safety issues of mixture and the method to control or weaken their combustion are highly concerned. To explore the inhibition effect of halogenated fire suppressants on the mixture, the effect of HFC-227ea on the laminar premixed methane/air flames, with different fractions of H₂, have been studied. Burning velocities have been measured with constant-volume combustion chamber and kinetically modelled a recently assembled kinetic mechanism. The fractions of H₂ influence the enhancement and inhibition effect of HFC-227ea, and it is less effective with the lean mixture. In stoichiometric condition, HFC-227ea showed good inhibition effect on the mixture flames. The HFC-227ea increased the burning velocities of CH₄-0% H₂-air and CH₄-10% H₂-air flames at leanest condition, whereas the increased burning velocity arising from HFC-227ea not occurred as the addition of H₂ above 20%. Experimental results coincided well with numerical results, however the agreement was poor for the leanest flames at low agent loading. Lastly, kinetic mechanism analysis was used to interpret the combustion enhancement and inhibition effect of hydrogen-doped methane flame by HFC-227ea.     

Graphical tools for conditional probabilistic exploration of multivariate spatial datasets

Two exploratory data analysis techniques the comap and the quad plot are shown to have both strengths and shortcomings when analysing spatial multivariate datasets. A hybrid of these two techniques is proposed: the quad map which is shown to overcome the outlined shortcomings when applied to a dataset containing weather information for disaggregate incidents of urban fires. Common to the quad plot, the quad map uses Polya models in order to articulate the underlying assumptions behind histograms. The Polya model formalises the situation in which past fire incident counts are computed and displayed in (multidimensional) histograms as appropriate assessments of conditional probability providing valuable diagnostics such as posterior variance i.e. sensitivity to new information. Finally we discuss how new technology in particular Online Analytics Processing (OLAP) and Geographical Information Systems (GISs) offer potential in automating exploratory spatial data analyses techniques, such as the quad map.     

轧机生产线CO_2灭火控制系统的设计与施工

针对轧机生产线的火灾特点论述了灭火装置类型的选择和控制系统的设计特点,并论述了火灾自动控制系统的控制机理和控制方式。该系统对有色加工企业轧机生产线自动灭火控制系统的设计施工具有实际指导意义。     

Better safe than sorry - Emergency knowledge and preparedness in the German population

Emergency situations require immediate reaction in order to mitigate their negative effects. Being prepared for an emergency entails having preparedness measures present. The present study investigated the impact of socio-demographic and emergency factors (i.e., experience, risk perception, perceived and objective emergency knowledge) on fire and medical emergency related preparedness. A telephone survey was conducted in a representative German sample (N = 2225). Results revealed that both objective and perceived knowledge increased the likelihood not only for adopting preparedness measures but also for their consideration. The impact of socio-demographic variables on preparedness varied among the respective preparedness items with a greater impact of collective factors (e.g. people in the household, children, marital status) as compared to individual factors like age and gender. The need for safety trainings and their repetition is discussed.     

Modeling thermal response of steel–concrete floor systems in a furnace

A methodology was developed to predict the thermal exposure from a furnace onto a floor assembly specimen. In furnaces with low conductivity wall linings and gas fired burners with complete combustion, the gas attenuation effects were determined to be small indicating that radiation between surfaces and convection are the dominant modes of heat transfer. This was modeled by assigning the internal furnace wall temperature to the furnace time–temperature exposure and performing a three-dimensional heat transfer analysis on the specimen. The furnace exposure model predicted heat transfer to the specimen surface that was within 5–14% of measured heat fluxes. The proposed furnace exposure methodology was used to predict the temperature rise of steel in a floor assembly where the test specimen can view itself as well as the furnace, making radiation exchange an important aspect of the problem. Predictions were within 5–10% of the measured values, which was within the experimental uncertainty.     

Indices for the evaluation of wildfire spread simulations using contemporaneous predictions and observations of burnt area

Methods to objectively evaluate performance are critical for model development. In contrast to recent advances in wildfire simulation, there has been limited attention to evaluating fire model performance. Information to validate fire models is typically limited, commonly to a few perimeter observations at a small number of points in time. We review metrics for comparing two burnt areas at a point in time: observed and predicted. These are compared in an idealised landscape and with a case study evaluating the performance of simulations of an Australian wildfire. We assessed: Shape Deviation Index (SDI), Jaccard's coefficient, F1, Sørensen's Similarity and Area Difference Index (ADI). For decomposing fit into error components (overprediction and underprediction) we assessed the partial indices of SDI and ADI, Precision and Recall. The various metrics were evaluated for their ability to represent error and their suitability for use in model improvement frameworks.