Establishing safety distances for wildland fires

In wildland fires, safety zones should be considered concerning people who are intervening in the emergency or attempting evacuation. To establish such zones, the solid flame model, together with the view factor calculated from a previously selected equation, was used to estimate the thermal radiation emitted by the flame front of a wildland fire. After determining the flame heights yielded by the 13 fuel types in the Rothermel classification for surface fires, and for crown fires in various Mediterranean forests, the thermal radiation was calculated for each scenario as a function of the distance. These data, together with threshold values for the vulnerability of people (protected or unprotected) and houses to thermal radiation, allowed for a set of safety distances for different situations to be obtained. These safety distances can be applied both in territory planning and in emergency situations.     

Limiting case fires arising from fuel tank/pipeline ruptures

Liquid and liquefied gas fuels will continue to play a predominant role in the energy picture of this country. Critical safety problems arise in connection with their storage and transportation. The problems become intrinsically serious in connection with military and civil aircraft operations, and accidents involving them. In an attempt to classify the varieties of fires which could arise with fuel tanks, an examination of such variables as the rupture size and location, pressure difference across the rupture, thermal properties, physicochemical properties, etc., is made to identify the circumstances when a pool fire, a flowing film fire, a falling film fire, a spray fire, and a gas fuel jet fire would evolve. Based on this framework, a review of scientific literature is made to seek an understanding of the basic heat and mass transfer phenomena involved in the associated diffusive combustion process. Areas in need of future scientific research are identified.     

Extinguishing agents for hydrocarbon fuel fires

This paper is a review of the extinguishing agents available for combating hydrocarbon fuel fires. The original work was done to set the state for a proposed laboratory test procedure to evaluate all known fire extinguishing agents that have been recommended for use in controlling and extinguishing aircraft fuel fires. This paper was the basis of the remarks made by the author during the Civil Aviation Workshop session of the National Fire Protection Association's 72nd Annual Meeting in Atlanta, Ga., on May 21, 1968.     

A combined overall and surface energy balance for fully-developed ventilation-controlled liquid fuel fires in compartments

As part of the research to extend the understanding of fully-developed wood fires to non-cellulosic fuels, the outline of a theoretical energy balance for a liquid fuel fire in a compartment is presented. A computer solution of the heat balance is described and the results of simulated fires are given to illustrate the uses of the model and the limitations of the assumptions made in the theory.The results show systematic departures from the well known assumption of the constancy of the ratio of burning rate to ventilation rate; this can account for some of the scatter commonly found in measurements of this ratio.     

Spilled liquid fires in tunnels

The study focuses on release of liquids inside tunnels from tankers containing dangerous good. Experiments and analysis from large scale tests are presented. The tests include different leakage rates, leakage type, liquids, spillage sizes on sloping surfaces and heat release rates. Models for estimation of leakage rates, spillage sizes and heat release rates for different scenarios are presented. The results are important to use in the design of active fire protections systems in tunnels including ventilation, fixed fire-fighting and drainage systems.     

Combustion properties of large liquid pool fires

Data from a number of large liquid pool fire experiments, recorded at the Fire Research Institute of Japan over more than a dozen years, were gathered and compiled. Burning rate and radiative outputs of gasoline, kerosene, and heptane were of primary interest. It is difficult to deduce the behavior of large fires from data on small fires because of the likelihood of decreasing combustion efficiency and heavy soot generation with resulting blockage of radiation. The data compiled here is possibly the largest body of data available for study on large pool fires.     

Internal separation distances for underground explosives storage in hard rock

Most recent studies on underground explosives storage have focused their attention on external safety distances, mostly inhabited distances for airblast, debris, and ground shock. Internal distances in prevailing codes generally deal with the need to prevent sympathetic detonation as a result of propagation by rock spall impact, or to prevent damage in an adjacent chamber in the event of an accidental explosion. For complex facilities, guidelines on separation requirements are often lacking. Also, there are several inconsistencies in the current separation requirements. This paper attempts to fill in the gap and rationalise the separation requirements for the various components of an underground storage facility. Recommendations will be made based on a comprehensive review of tunnel damage and results from large-scale tests.     

The use of ground cover materials to suppress fuel fires at airports

Crushed rock has demonstrated a capability for retarding flame spread in hydrocarbon fuel fires. What are the effects of rock size, depth of fuel surface below ground cover surface, and fuel flash point in flame suppression?     

Fighting building fires with liquid nitrogen: A literature survey

Brief reference is made to inert gases having some potential for fighting building fires and it is suggested that nitrogen, or to be more accurate the massive use of liquid nitrogen, stands out as being the most promising for immediate consideration. Reports and publications produced in the last twenty years on the use of liquid nitrogen are reviewed. It is concluded that its effectiveness and the elimination of the water damage often resulting from conventional firefighting make it desirable for firefighters to gain experience in its use with a view to determining whether or not it should supersede the use of water in fighting many building fires.     

从仓储库房火灾中获得的经验和教训

历史的经验表明,当灾害性火灾发生后,人们对火灾进行调查所获得的经验和教训推动了仓储库房防火的进步。下面讨论由这种方式得出的经验和教训。1自动喷水灭火系统的设计应和火灾危险相匹配该教训来源于含有可燃物质的气溶胶罐仓库的自动喷水灭火系统的防火评估。1978年在新泽西     

高层建筑火灾反映的问题

俄罗斯各大城市的建筑急剧增高。到今天,十四至二十八层高的楼房在各地区都很常见。在莫斯科,高达200~300m的国际事务中心“莫斯科商业中心”则是一个名符其实的“摩天大楼”。欧洲最高的住宅楼“凯旋小区”也早已投入使用。但遗憾的是,高层建设的热潮也引发了一系列与高层消防     

封闭空间火灾中燃料烟尘对墙体所受热通量的影响

尽管在封闭空间内已经做过很多关于气体温度和燃烧率的研究,但目前仍然缺乏封闭空间内墙体上热通量及其分布方面的信息。该热通量数据是确定墙体材料特别是玻璃的热反应及性能的必要输入参数。试验用封闭空间墙体上的热通量是通过多块薄钢片(25.4mm×25.4mm×3mm)以及钢片周围隔热材料的温度推算出来的。另外,笔者还测量了热流计附近墙体的质量损失率和温度。试验用封闭空间是ISO标准墙脚火试验的1/3,有六个开口,燃料为甲醇、IMS(工业用甲基化酒精)以及甲苯,装在大小不同的三个方形油盘里,油盘放置在封闭空间的内外拐角处。在选择燃料方面,笔者的依据是燃料燃烧产生的烟尘应越来越浓。试验发现,与以前对地板的研究结果有所不同的是,墙体上的热通量不仅仅取决于烟气温度,还取决于热释放速率的强弱以及燃料所产生的烟尘的多少。另外,对甲醇、IMS以及甲苯所产生的热通量的比较发现,对流热可以与辐射热通量(热烟气流以及封闭墙体造成)以及来自烟羽流的辐射热通量分开。     

Heat radiation from fires of aviation fuels

As a practical matter, the horizontal radiation profile of a free-burning fire may be more significant than the vertical profile from a fire-fighting point of view. Note: Presented at the 1972 Fall Meeting, Eastern States Section, The Combustion Institute, December 7–8, 1972, Princeton University, Princeton, NJ.     

The effect of surroundings with different separation distances on surface pressures on low-rise buildings

Very large roof suctions on low-rise buildings occur for isolated buildings during both full-scale experiments and wind tunnel tests performed by many investigators. This paper investigates the sensitivity of these high suctions to the presence of multiple surrounding building configurations. This study uses the Wind Engineering Research Field Laboratory (WERFL) building studied during the CSU/TTU Cooperative Program in Wind Engineering as a basic building shape. A model of the WERFL structure was constructed to a 1:50 scale and instrumented with multiple pressure ports. Pressure taps on the 1:50 scale building model were connected to two 48-channel PSI transducer units. A large number of “dummy” models of similar dimensions were constructed to represent surrounding buildings. These model buildings were arranged in various symmetric configurations with different separation distances, and placed in the Industrial Wind Tunnel of the Wind Engineering and Fluids Laboratory, Colorado State University. Measurements include mean, RMS and peak pressures, street canyon velocity profiles and laser-sheet flow visualizations. Shelter effects produced by the surrounding buildings on the central instrumented building were found to be significant, such that flow patterns are displaced and mean and peak induced loads are significantly different from the isolated building base case. The surface pressures of master WERFL model inside the urban street canyons were determined by the prognostic model FLUENT using the four differences closure approximation and FDS, large eddy simulations methodology. Calculations are compared against fluid modeling from wind-tunnel test.     

Predicting the heat release rates of liquid pool fires in mechanically ventilated compartments

In this paper we perform predictive simulations of liquid pool fires in mechanically ventilated compartments. We show that steady state burning rates are accurately predicted using a detailed model for the liquid phase heat transfer. The effect of lowered oxygen vitiation on the burning rate of pool fires is correctly captured. Simulations were done using the Fire Dynamics Simulator and the experiments considered were conducted in the OECD PRISME project. The main difference between the present study and previous simulation studies is the use of a detailed liquid evaporation model and the direct calculation of the vitiation and thermal environment interactions through the CFD solver.     

液体燃料在水面上的燃烧

1简介 液体燃料在水面上燃烧对禁火地区是一种严重的潜在危险。虽然燃料燃烧本身与单成分燃料的燃烧相差不多,但水的存在则可引发某些特殊的效应,这些效应都是由燃料热传到其下的水中所导致的。这种深层热传递可使水发生沸腾和飞溅,这种现象通称喷溅（也称扬沸或沸喷）。     

Effect of scale and fuel type on the characteristics of pool fires for fire fighting training

This paper examines the effects of pool size and fuel type on the characteristics of pool fires. The fuels studied include hydrocarbon solvents, alcohol and their blends. The large-scale experiments were conducted on 0.445 and 1 m diameter pools in two enclosures: 41 m long×5.4 m wide×2.4 m high and 25 m long×2.7 m wide×2.4 m high, under a ventilation rate of 1–1.2 m/s. In these tests, measurements of the fuel pyrolysis mass loss rate, heat release rate (from CO₂ and CO concentrations as well as oxygen depletion), smoke extinction area (from laser attenuation), total heat flux emanating from the flame, and the yields of CO₂ and CO were made. Bench-scale tests were conducted using the same fuels and fuel blends on 100 mm× 100 mm pool fires in a Cone Calorimeter—a well-known fire test method.

The hydrocarbon+alcohol fuel blends are used to create large pool fires for fire fighting training. The aim of this study was to: (1) Formulate a fuel blend which will produce a “hot” fire for realistic fire fighting training while generating a minimal quantity of smoke to comply with the pollution regulations. (2) Investigate the effect of fuel type and scale on the properties of the pool fires. (3) Make comprehensive measurements on pool fires in tunnels which can be used for validating mathematical fire models.

This study has resulted in the formulation of a fuel blend which satisfies the requirements of fire fighting training as well as Environment Protection Authority of New South Wales. The bench and the large-scale results correlate well showing good agreement between the heat of combustion, smoke extinction area (SEA) and the yields of CO₂ and CO. The SEA increases with the CO and CO₂ yields which in turn increase with the carbon fraction and the aromatic content of the fuel/fuel blend. The SEA correlates strongly with the CO and CO₂ yields and in both the correlations, the entire data collapse on a single curve. These correlations indicate that the SEA and the CO₂ and CO yields vary mainly with the fuel type, and not so much with the pool size. The flame heat flux increases with the carbon content in the fuel.     

Dispersion of toxic combustion products from large fires

Conclusions The computer models discussed here are used by MHAU to give an initial indication of the possible hazards to the local population from the dispersion of combustion products from large fires.Agreement between the computer model and the wind tunnel data is encouraging, particularly at relatively low values of the buoyancy flux parameterF U ^–3 L ^–1. HSE is proposing to commence large-scale dispersion trials in the open air in the near future. It is hoped that this will enable greater confidence to be had in the predictions of the computer models.Symbols c Specific heat (J kg^–1 K^–1) - g Acceleration due to gravity (m s^–1) - H Plume thickness (m) - H Plume rise (m) - L Length scale (m) - L _p Lift-off parameter - Q Heat release rate (MW) - T Temperature (K) - U Windspeed (m s^–1 - U ^* Friction velocity (m s^–1) - x Distance (m) - x _v Horizontal virtual component (m) - Z Vertical virtual component (m) - r Density (kg m^–3) - r Density difference (kg m^–3)