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Cable fires are one of the main fire hazards in nuclear power plants. As part of the cable fire spreading (CFS) campaign of the OECD PRISME‐2 programme, 3 real‐scale cable tray fire tests were performed in open atmosphere (1 CFS support test, named CFSS‐2) and in a confined and mechanically ventilated facility (2 CFS tests, named CFS‐3 and CFS‐4). This study aims at investigating the effects of confined and ventilated conditions on cable tray fires that used a halogen‐free flame retardant cable‐type. The CFS‐3 and CFS‐4 tests involved 2 ventilation renewal rates of 4 and 15 h?1, respectively. The confined conditions lead to decrease the fire growth rate and the peaks of mass loss rate and heat release rate, compared with open atmosphere. The reductions are larger for the lower ventilation renewal rate. Furthermore, it is shown that the CFS‐4 test may be classified as a well‐ventilated fire and the CFS‐3 test as an under‐ventilated fire. For this last one, its fire characteristics and its consequences in the fire room highlight an oscillatory behaviour, with the same low frequency, for about 30 minutes. These oscillations arise from successive combustions of unburnt gases. 相似文献
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Cable fires are one of the main fire hazards present in nuclear power plants (NPPs). Therefore, as part of the Organisation for Economic Co‐operation and Development (OECD) PRISME‐2 project, cable tray fire tests were performed both in open atmosphere conditions and in a confined and mechanically ventilated facility, called DIVA. These tests aim at showing the effects of a confined and ventilated environment on fire characteristics and consequences. This study deals with five fire tests, which used halogenated (poly [vinyl chloride] or PVC) cable types. Two tests were carried out in open atmosphere and three tests in the DIVA facility. The latter used a ventilation renewal rate (VRR) of either 4 or 15 h?1. The confined and ventilated conditions reduced the mass loss rate and heat release rate than did those obtained in open atmosphere. Furthermore, the three confined tests produced unburnt gases, which ignited in the fire room. Two explosions were highlighted for the tests that used a VRR of 4 h?1. These explosions indeed led to fast flame propagations over the entire upper part of the fire room and steep overpressures of almost 150 hPa. The low‐qualified PVC cables and the ventilation set‐up used in this study strongly contributed to the occurrence of these explosions. 相似文献
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Matthias Siemon Olaf Riese Burkhard Forell Dominic Krnung Walter Klein‐Heßling 《火与材料》2019,43(5):497-513
In the context of industrial buildings and power plants, electrical installations and cable trays represent a main fuel load and a potential initial fire source due to possible short circuits or comparable malfunction. Furthermore, a fire can spread from one tray to additional trays mounted above and/or horizontally on one tray. Because of the high significance of cable fires, several research projects have been carried out, investigating the fire behaviour of cables from small‐scale tests, eg, the cone calorimeter, up to large‐scale tests, analysing complete cable tray constructions. The goal of the work presented in this paper is the extension of the knowledge regarding the influence of geometrical parameters like the packing density and tray distance on the burning behaviour and fire spread of cable tray installations. The results are considered, together with test results from the literature, to quantify the main physical parameters describing the burning behaviour. In a next step, the general applicability of these parameters as input data for the parametrization of the source term of numerical simulations is shown. The test results show that the burning behaviour and the fire spreading highly depend on the cable arrangement of the cables on the cable tray, in combination with other boundary conditions. By applying the results as input for a fire simulation, the mass loss rate is considered appropriately. 相似文献
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Xianjia Huang He Zhu Lan Peng Zihui Zheng Wuyong Zeng Kun Bi Chihonn Cheng Wanki Chow 《火与材料》2019,43(1):64-73
Cable fire risk analysis is important for fire protection design in nuclear power plants, where multiple horizontal cable trays are mostly located on the walls. Fire experiments using three cable trays with different cable arrangements were conducted in a confined room to investigate the burning behavior of a cable tray on a wall. A corner was formed by the side wall and the cable tray. Hot smoke emitted from the burning cable was trapped in the corner and then ignited the cable on the bottom surface of the upper cable tray. It is found that for cables densely packed together, spread of flame on the bottom surface of cable tray was clearly observed and increased the mass loss of cable burning during the growth stage of a cable tray fire. For cables arranged further apart, vertical propagation from the bottom tray to the top tray was fast and dominated the mass loss of cable burning. 相似文献
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A new flame spread apparatus for the measurement of flame spread rates at different ambient temperatures is presented. A 2‐m long sample is pre‐heated with air to the desired temperature and ignited from its lower end with a small propane burner. The flame spread is traced with thermocouples in contact with the sample surface. The features and function of the new apparatus are described, as well as series of vertical flame spread experiments on cylindrical birch rods and electrical cables made of polyvinylchloride (PVC) and flame retardant non‐corrosive (FRNC) materials. Vertical flame spread rates 6–62 mm/s (temperature range 22–271 °C) were determined for birch samples, 3–24 mm/s (22–190 °C) for PVC cable samples, and 0–4 mm/s (22–293 °C) for FRNC cable samples. Small‐scale experiments with thermogravimetric analysis and cone calorimeter were performed to characterize the sample materials in terms of their thermal and fire behaviour. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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The Grenfell Tower fire occurred on 14 June 2017, killing 72 people. The pattern and speed of vertical and horizontal fire spread characterize this catastrophic event. Plentiful video and photographic data of the fire spread available has been carefully verified and concatenated into a database. The verified data have been superimposed on a projection of the Grenfell Tower in order to track the development of the fire. The surface that is unburnt, burning, or extinguished, as well as the presence of internal fire at any given location, is thus recorded for the duration of the fire. An analysis of the results showed that the initial vertical propagation can be divided into three phases. After the façade ignited at the fourth floor, vertical propagation over time is linear, with a vertical fire spread rate of around 3.5 m/min until the fire reached the sixth floor. Then fire propagation decelerated. Finally, fire spread accelerated with a power four dependence. The maximum vertical fire spread rate was around 8 m/min as the fire reached the crown at the top of the building. Horizontal spread proved to be greatest at the level of the crown (0.293 ± 0.005 m/min). There is a linear relationship between speed of horizontal fire spread and height. These correlations and observations yield important conclusions, and eight different hypotheses capable of explaining the global behaviour of the fire are suggested. 相似文献
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依照电力电缆的特点和膨胀型防火涂料的膨胀防火机理,筛选涂料各组分原料。通过实验, 确定出合理的涂料配方。所生产的涂料经检测,各项理化指标均达到要求,防火性能达到了一级。 相似文献
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随着消防审查的日趋严格及新规范GB 50974—2014《消防给水及消火栓系统技术规范》的实施,对消防设计的要求也更加严格。以北方某煤制油项目消防站、中心控制室及中心化验室为例,简要介绍成组布置的重要辅助设施消防设计的思路及设计过程中存在的问题。 相似文献
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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. 相似文献
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文章针对近年来随着社会的发展,各类电气产品的广泛应用而造成电气火灾事故居高不下,电气火灾的起数多,损失大,人员伤亡多等指标上升的特点,为加强电气火灾预防工作,根据电气火灾的规律和特点,采取有效措施预防电气火灾的发生,有针对性地提出推广应用电气火灾监控系统技术,提高防控电气火灾的能力,达到防患于未然的目的。同时对电气火灾监控系统在应用过程出现的问题提出了相应的对策,将对保护经济社会发展和人民生命财产安全有着积极的作用。 相似文献
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Failure analysis normally requires many forms of investigation, but visual examination is the most used amongst all possible techniques. However, as the legal climate for fire investigation is becoming more rigorous, fire researchers need to work differently. In other words, to be technically defensible, expert testimony must be built on scientific data. To this aim, in‐depth microstructural analyses of materials are particularly suitable to define the fire scene. This paper discusses some of the basic metallurgical theories used in failure analysis of copper, steel and aluminium alloy components involved in fire situations. Some components that can be easily found in fire and arson scene were submitted to simulated fire for indicated time and temperature. The collected samples were than examined by optical microscopy, scanning electron microscopy and energy‐dispersive spectroscopy. Oxidation, recrystallization, second‐phase precipitation and melting were some of the features observed on samples that can be strictly related to the thermal effect of fire. On the basis of these metallurgical results and starting from the evidence that different exposure temperatures can induce different metallurgical modifications, it is possible to define the temperature range experienced by various components, thus suggesting the fire dynamic during the incident. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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具有过渡点温度特性导线是用线膨胀系数比钢线小很多的材料(如碳纤维复合材料)替代钢芯,与外层铝线绞制成特殊导线。该导线芯线具有极佳的耐热性和低线膨胀系数,可将导线允许温度提高至160℃或更高,从而提高了导线的输送容量,并且导线具有低弧垂特性。这种导线的架线力学特性与钢芯铝绞线不同,应用弹性变形的虎克定律以及导线悬链线方程推导了具有过渡点温度特性导线的过渡点温度和张力的计算方法,已在辽宁省多条送电线路的架线设计中应用,取得了很好的效果。 相似文献
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利用热重分析技术研究了阻燃电缆绝缘材料聚氯乙烯的热解过程。对样品在不同升温速率、不同气氛下的热解行为进行了实验研究。结果发现,升温速率从5℃/min增加到15℃/min时,样品的失重率从58.987%增加到59.519%,初始分解温度从320.08℃增加到337.09℃;与N2气氛相比,空气气氛下第一阶段的热解较滞后,且热解过程温度跨度较大,热解过程比较复杂,失重率更大;随着氧体积分数的增加,热解进程加快,相应微分热重曲线上的失重峰均有所提前且峰高增大,对应的残余量也减小。 相似文献
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Electrical cable trays are used in large quantities in nuclear power plants (NPPs) and are one of the main potential sources of fire. A malfunction of electrical equipment due to thermal stress for instance may lead to the loss of important safety functions of the NPPs. The investigation of such fires in a confined and mechanically ventilated enclosure has been scarce up to now and limited to nuclear industry. In the scope of the OECD PRISME‐2 project, the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) conducted more than a dozen fire tests involving horizontal electrical cable trays burning either in open atmosphere or inside mechanically ventilated compartments to investigate this topic. A semi‐empirical model of horizontal cable tray fires in a well‐confined and mechanically ventilated enclosure was developed. This model is partly based on the approach used in FLASH‐CAT and on experimental findings from IRSN cables fire tests. It was implemented in the two‐zone model SYLVIA. The major features of the compartment fire experiments could then be reproduced with acceptable error, except for combustion of unburned gases. The development of such a semi‐empirical model is a common practice in fire safety engineering concerned with complex solid fuels. 相似文献