摘要 :
The development of fire-safety measures for high-speed passenger trains has been focused on preventing fire initiation or delaying fire growth and spread through small-scale tests of the materials used in trains. However, new fire...
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The development of fire-safety measures for high-speed passenger trains has been focused on preventing fire initiation or delaying fire growth and spread through small-scale tests of the materials used in trains. However, new fire-safety approaches for trains consider a systemic approach. This approach considers numerous global factors that influence fire dynamics, such as the influence of vehicle design, selection of materials, and active and passive protection systems installed. In the present paper, the results of small-scale and full-scale tests carried out on the new generation of high-speed trains operating in Spain are presented. This rolling stock is classified as category B according to the Technical Specification for Interoperability and Operation Category 3 according to EN 45545-1. The results confirmed good fire behaviour using both approaches (small and full-scale tests). Additionally, several analyses have been performed, including an analysis of the quality of materials used for making different components of the passenger compartment and the influence of ignition source position on fire development.
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Two full-scale fire experiments were conducted to determine the mode of penetration of a tire fire into the passenger compartment of a motorcoach. A special burner was designed to imitate the frictional heating of hub and wheel me...
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Two full-scale fire experiments were conducted to determine the mode of penetration of a tire fire into the passenger compartment of a motorcoach. A special burner was designed to imitate the frictional heating of hub and wheel metal caused by failed axle bearings, locked brakes, or dragged blown tires. For the first experiment, heating to obtain tire ignition was initiated on the exterior of the passenger side tag axle wheel and for the second, on the exterior of the passenger side drive axle wheel. Measurements of interior and exterior temperatures, interior heat flux, and heat release rate were performed. Standard and infrared videos and still photographs were recorded. Both experiments showed that the tire fires ignited the plastic fender and glass-reinforced plastic exterior side panel (below the windows) upon which the fires spread quickly and penetrated the passenger compartment by breaking the windows. Measurements showed that other potential fire penetration routes (flooring and lavatory) lagged far behind the windows in heating and degradation.
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Three full-scale fire experiments were conducted to assess methods of hardening the motorcoach against penetration of a tire fire. The first method was to replace the combustible fender and exterior side panel above the wheels wit...
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Three full-scale fire experiments were conducted to assess methods of hardening the motorcoach against penetration of a tire fire. The first method was to replace the combustible fender and exterior side panel above the wheels with stainless steel sheet metal. The second method was to coat the plastic fender and side panel with an intumescent layer. The third method was to install a sheet steel fire plume deflector between the fender and side panel. A special burner was used that imitates the frictional heating of hub and wheel metal caused by failed axle bearings, locked brakes, or dragged blown tires. For each experiment, heating to obtain tire ignition was initiated on the exterior of the passenger side tag axle wheel. Measurements of interior and exterior temperatures, interior heat flux, and heat release rate were performed. Standard and infrared videos and still photographs were recorded. The experimental results were compared with those obtained with no fire hardening. The metal replacement method performed best and prevented fire penetration for over 30min longer than the nonhardened cases. The intumescent coating extended fire penetration by about 20min longer than the nonhardened cases. The steel plume deflector had no significant impact on the timing for fire penetration of the windows. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
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Full-scale fire experiments were conducted at the National Institute of Standards and Technology (NIST) to investigate tire fire interactions with the passenger compartment of a motorcoach. A single full-scale experiment with a pa...
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Full-scale fire experiments were conducted at the National Institute of Standards and Technology (NIST) to investigate tire fire interactions with the passenger compartment of a motorcoach. A single full-scale experiment with a partially furnished interior was conducted to investigate tire fire growth within the passenger compartment and the onset of untenable conditions. A tire fire was initiated using a burner designed to imitate the frictional heating of hub and wheel metal caused by failed axle bearings, locked brakes, or dragged blown tires. Measurements of interior and exterior temperatures, interior heat flux, heat release rate, toxic gases, and visibility were performed. Standard and infrared videos and still photographs were also recorded. The results of this single experiment showed that after fire penetration into the passenger compartment, the tenability limits were reached within 8 minutes near the fire and within 11 minutes throughout the passenger compartment.
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Wildland fire rate of spread (ROS) and intensity are determined by the mode and magnitude of energy transport from the flames to the unburned fuels. Measurements of radiant and convective heating and cooling from experimental fire...
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Wildland fire rate of spread (ROS) and intensity are determined by the mode and magnitude of energy transport from the flames to the unburned fuels. Measurements of radiant and convective heating and cooling from experimental fires are reported here. Sensors were located nominally 0.5 m above ground level. Flame heights varied from 0.3 to 1.8 m and flaming zone depth varied from 0.3 to 3.0 m. Fire ROS derived from observations of fire transit time between sensors was 0.10 to 0.48 m s(-1). ROS derived from ocular estimates reached 0.51 m s(-1) for heading fire and 0.25 m s(-1) for backing fire. Measurements of peak radiant and total energy incident on the sensors during flame presence reached 18.8 and 36.7 kW m(-2) respectively. Peak air temperatures reached 1159 degrees C. Calculated fire radiative energy varied from 7 to 162 kJ m(-2) and fire total energy varied from 3 to 261 kJ m(-2). Measurements of flame emissive power peaked at 95 kW m(-2). Average horizontal air flow in the direction of flame spread immediately before, during, and shortly after the flame arrival reached 8.8 m s(-1), with reverse drafts of 1.5 m s(-1); vertical velocities varied from 9.9 m s(-1) upward flow to 4.5 m s(-1) downward flow. The observations from these fires contribute to the overall understanding of energy transport in wildland fires.
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It is observed that some big terminal buildings were functioning as more than just a passenger terminal, leading to the placing of combustibles in the big hall. For example, polyurethane sofas were put in areas providing catering ...
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It is observed that some big terminal buildings were functioning as more than just a passenger terminal, leading to the placing of combustibles in the big hall. For example, polyurethane sofas were put in areas providing catering services. A preliminary fire hazard assessment based on the identified scenario on burning those combustibles will be reported in this paper. Hazard assessment included studying the heat release rate, smoke filling in the hall and the air temperature distribution. Full-scale burning tests, empirical equations on key parameters and computational fluid dynamics are used. It is not good practice to close businesses in this economic climate. Therefore, remedial actions such as spraying fire retardant coatings which can stand higher radiative heat fluxes in case of accidental fire, and implementing appropriate fire safety management are recommended.
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Prescribed burning is an essential tool for forest and rangeland management that requires specific weather conditions to enable the efficient and safe application of fire. Prescribed burning is often limited by the ability to find...
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Prescribed burning is an essential tool for forest and rangeland management that requires specific weather conditions to enable the efficient and safe application of fire. Prescribed burning is often limited by the ability to find suitable burn-days that fit within the identified weather parameters that balance good smoke dispersion and erratic fire behaviour. We analysed the sensitivity of the occurrence of widely used weather windows in the southeastern USA to modest changes in how they are defined. This analysis identified the most limiting prescription components and assessed where small changes in the prescription window can yield the greatest gains in additional burn-days. In the growing season (April-September), adjustments to mixing height offered the greatest such opportunity: a 12.5% increase in the upper-limit yields similar to 25% more burn-days during this period. During the dormant season (November-January), a 12.5% change in the upper-limit of transport wind yields similar to 20% more burn-days. Performing this analysis on the ventilation index revealed that comparable increases in burn-days were available by changing its upper limits. These results help inform ongoing discussions on potential changes to regional prescribed burn weather parameters that might help meet smoke management and treatment objectives in the southeastern USA and more broadly.
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Air pollution over the Yungui Plateau (YGP) in southwestern China can be caused by the transport of biomass burning aerosols from Southeast Asia; however, the magnitude and mechanisms of such long-range transport have not been ful...
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Air pollution over the Yungui Plateau (YGP) in southwestern China can be caused by the transport of biomass burning aerosols from Southeast Asia; however, the magnitude and mechanisms of such long-range transport have not been fully investigated. Here, we studied the impacts of fire emissions on vertical PM_(2.5) over the YGP and the transport mechanisms of PM_(2.5) during the fire seasons (March-April) of the neighboring Indo-China Peninsula (ICP) region in 2015-2019 using ground-based monitoring data, reanalysis of meteorology, and GEOS-Chem model simulations. Average daily PM_(2.5) concentrations of 36.06 ± 14.86 μg m~(?3) were measured at 16 ground stations in the YGP with the highest value of 53.77 μg m~(?3) at Xishuangbanna, the nearest station to the ICP. Model simulations showed that fire emissions contributed approximately 50%-60% of the vertical PM_(2.5) over the YGP at a height of 3-4 km, with larger contributions in meridional than zonal cross-sections. Four weather patterns with low pressure over the YGP were identified as favorable conditions for smoke transport. The pattern with the lowest pressure over the northern YGP and the strongest vertical wind disturbance was the most favorable for the eastward transport of fire air pollution to the YGP. Another pattern, which had the strongest southerly wind, promoted smoke aerosols to climb from eastern Myanmar and northern Laos/Vietnam to the YGP. Through these typical pathways, ICP biomass burning significantly impacted PM2.5 pollution in southwestern China.
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The NIST Firebrand Generator (NIST Dragon) has been used to quantify the vulnerability of structures to ignition by firebrand attack. The Firebrand Generator is a useful device to study firebrand transport, and has been used to va...
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The NIST Firebrand Generator (NIST Dragon) has been used to quantify the vulnerability of structures to ignition by firebrand attack. The Firebrand Generator is a useful device to study firebrand transport, and has been used to validate transport models of firebrand showers. During this series of experiments, the Firebrand Generator was fed with wood cubes of uniform size. The glowing firebrands generated were collected in an array of water-filled pans that were arranged to collect the bulk of the lofted firebrands. The pan arrangement was determined from repeated preliminary studies. These experiments were performed over a range of wind speeds (up to 9 m/s) to determine the lofting distance. The major change in these experiments from prior work was that, for a given wind speed, the firebrand size and mass was determined at each pan location. In the past, it was only possible to determine the number distribution; specifically the number of firebrands at each spatial location was counted (not resolved at every pan but only across a given row of pans). Statistical analysis indicated that a normal distribution was able to capture the number/mass percentage versus horizontal distance. This study provides even greater fidelity measurements to validate transport models of firebrand showers, and further insights into firebrand generation.
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Purpose – In recent years, there has been a substantial increase in the number of fuel-truck accidents involving fire outbreaks in Oyo State, Nigeria. These accident explosions have mechanical-induced actions on the road, with po...
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Purpose – In recent years, there has been a substantial increase in the number of fuel-truck accidents involving fire outbreaks in Oyo State, Nigeria. These accident explosions have mechanical-induced actions on the road, with potential costly damages to structures and non-structural property exposed to them, and loss of lives. The need to understand causes of these accident scenarios become important in order to properly plan to avoid them. The purpose of this paper is to reveal results of a survey is carried out to reveal important elements of fuel-truck accident in Nigeria. Design/methodology/approach – A survey was carried out to determine the various causes of accidents and rollover fire outbreaks in fuel trucks in Oyo State, Nigeria, using primary data collected from field and secondary data obtained from the Nigeria Police, Road Safety Commission and Fire Services Agency. Findings – From about 358 transport accidents recorded in Nigeria between 1999 and 2002, only 33 were due to cars while the rest involved trucks and heavy-duty vehicles. The survey showed that about 32 per cent of truck drivers are below 30 years and probably immature. Also 62 per cent of fuel truck tanks manufactured are of inferior quality and may thus have been aiding fire outbreaks when there is an accident. The study also showed that about 54 per cent of tank leakages that may lead to fire outbreak are due to operators' carelessness. Practical implications – The study established the need for more education among the drivers and adequate legislation for tank manufacturers. Originality/value – The work is perhaps the first to investigate this important area of safety research in the study area. The work would be of value to safety practitioners.
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