不同影剧院座椅连排燃烧特性试验研究

利用10 MW大尺度量热计对不同影剧院座椅进行连排燃烧试验研究.建立座椅燃烧试验台,将15把影剧院座椅分3排台阶布置,通过对多人影剧院软质座椅排列在一起进行燃烧试验,提供燃烧产生的热释放速率、总热释放量、产烟速率、总产烟量相关特性信息.试验中,分别选取普通影剧院座椅与阻燃影剧院座椅分别进行连排燃烧试验,并将燃烧测试得到...     

山火条件下高压输电线路放电特性

利用单、双和三木垛火源和单股、双分裂和四分裂模拟高压导线研究了中尺度高压输电线路在火灾条件下的放电特性及其与火源火场参数的关系,提出了为防控火灾实际输电线路走廊内森林可燃物管理方法.结果发现,模拟导线在火焰中较纯空气中容易发生放电(火焰中空气平均击穿场强较纯空气中约下降64.9％);火持续时间、火焰高度和火灾荷载密度对平均击穿场强的影响程度依次减弱,火强度则是决定性影响参数(木垛火源双木垛火变为三木垛火时,空气平均击穿场强与火强度、火灾荷载密度、火持续时间及火焰高度增幅比分别为2.11、0.482、1.70和0.582);中高速中高强度的上山地表火、树冠火、冲冠火和地表火转化的树冠火易形成高火焰、高热量、高温度、高浓度(烟尘粒子和带电质点)的容易使线路跳闸的环境条件.     

Experiments on the interaction between individual products involved in the artane fire

The crucial aspect of the fire was the transition from one which did not pose an immediate threat to life to one which spread very rapidly. It was considered that the most likely mechanism for fire spread was the presence of long flames beneath the ceiling radiating heat downwards on to the sets beneath at an intensity sufficient to cause spontaneous ignition.

Preliminary estimates of the minimum size of fire necessary for this were made and some preliminary experiments carried out to determine the conditions under which a relatively small fire might have attained such a size. The most likely mechanism appeared to involve an interaction between fire on the seats and the carpet tiles on the walls.     

Effect of ignition conditions on upward flame spread on a composite material in a corner configuration

This paper focuses on the issue of fire growth on composite materials beyond the region immediately subjected to an ignition source. Suppression of this growth is one of the key issues in realizing the safe usage of composite structural materials. A vinyl ester/glass composite was tested in the form of a 90° corner configuration with an inert ceiling segment 2.44 m above the top of the fire source. The igniter was a square propane burner at the base of the corner, either 23 or 38 cm in width, with power output varied from 30 to 150 kW. Upward flame spread rate and heat release rate were measured mainly for a brominated vinyl ester resin but limited results were also obtained for a non-flame retarded vinyl ester and a similar composite coated with an intumescent paint. Rapid fire growth to the top of the sample was seen in replicate tests for the largest igniter power case; the intumescent coating successfully prevented fire growth for this case.     

Model scale tunnel fire tests with longitudinal ventilation

Results from a series of tests in a model tunnel (1:23) are presented. Tests were carried out with longitudinal ventilation under different fire conditions. Wood cribs were used to simulate the fire source, which was designed to correspond to a scaled-down HGV (Heavy Goods Vehicle) fire load. The parameters tested were: the number of wood cribs, type of wood cribs, the longitudinal ventilation rate and the ceiling height. The heat release rate, fire growth rate, maximum gas temperature beneath the ceiling, temperature distribution, total heat flux at floor level, flame length, and back-layering length were investigated. Correlations for these parameters were investigated and proposed for longitudinal flow in tunnels.     

Modeling fire growth in a combustible corner

A fire growth model was developed to predict the flame spread and total heat release rate of a fire in a corner configuration with a combustible lining. Input data for the combustible lining were developed using small-scale test data from the ASTM E1354 cone calorimeter and ASTM E1321 LIFT. The fire growth model includes a flame spread model linked with a two zone compartment fire model, CFAST Version 3.1.2. At a user selected time interval, the flame spread model uses the gas temperature from CFAST to predict the heat release rate of the fire at that time interval, and then provides CFAST with a new heat release rate to predict conditions during the next time step. The flame spread model is an improved version of the flat wall flame spread model previously developed for the US Navy. The model is capable of predicting flame spread in a variety of configurations including a flat wall, a corner with a ceiling, flat wall with a ceiling, unconfined ceiling, and parallel walls. The model has been validated against ISO 9705 test data and was used in this study to simulate conditions that develop in three open corner tests each with a different lining material. The model was able to predict the heat release rate of the fire and provide a reasonable estimate of the flame fronts and flame lengths during the growing fire.     

单室墙角火壁面烟熏痕迹特征研究

为研究单室墙角火火灾壁面烟熏痕迹特征，采用1/3尺寸火灾试验还原单室墙角火火灾，测定壁面不同点的温度及烟气蔓延速度，研究火源在不同位置时的壁面烟熏痕迹特征；利用PyroSim软件模拟烟气蔓延过程。结果表明：火源位于房间中间时，在屋顶呈现圆形痕迹；火源在墙角时，两边侧墙和墙角顶部形成明显烟熏痕迹；墙角火在墙角位置的温度和烟气蔓延速度高于房间中间起火；试验结果与模拟结果吻合。试验结果可为调查墙角火火灾提供理论及试验依据。     

轻型木结构建筑外墙火灾蔓延试验研究

搭建实体火灾试验平台,对窗口溢出火焰沿木骨架组合外墙竖向蔓延特性进行研究。根据不同的外墙饰面材料及构造设置3种典型的工况,分析火焰蔓延、炭化情况以及不同位置温度随时间的变化。结果表明,对于硅酸钙板作外饰面层且无空腔的构造,外墙火灾蔓延危险性最小;对于带空腔的水泥挂板构造,水泥挂板在火焰高温作用下出现变形和破裂,导致空腔后面OSB板被引燃,火焰和烟气沿空腔向上蔓延;对于带空腔的阻燃木挂板构造,外挂板在窗口火作用下经历了引燃、平缓燃烧、剧烈燃烧三个阶段,最终出现失控的火蔓延。对于带空腔的外墙构造,金属泛水条有助于减缓火灾的竖向蔓延。     

Thermal characteristics of fires in a noncombustible corner

A series of fire tests were conducted in a full-scale open corner with a ceiling to measure the thermal field generated by fires located in a corner. Fires were produced using different size (0.17, 0.30, and 0.50 m) square and line propane burners with heat release rates ranging from 25 to 300 kW. Burner distance below the ceiling was also considered. Measurements included flame length, gas temperatures, and total incident heat flux onto the noncombustible corner boundaries. Flame lengths were related to Q*, with the burner dimension as the length scale, and were found to be similar to those measured in studies with no ceiling. By dividing the corner into three regions (corner walls (z/H<0.8), top of the walls (z/H>0.8), and ceiling, empirical relations for estimating the gas temperatures and incident heat fluxes were developed. Incident heat fluxes on the corner walls were measured to be similar to those in other studies.     

The contribution of flames under ceilings to fire spread in compartments

An experimental investigation has been made of flames spreading beneath both combustible and non-combustible ceilings. Experiments were performed in a model representing the ceiling of a corridor with a fire at one end: a gas burner was used to represent the fire, this was replaced by wooden cribs in experiments to be described in later part of this report.

The flames rising vertically from the fire in effect drew air up into the horizontal layer of flames and gases beneath the ceiling. Depending on the rate of flow of fuel gas (or rate of burning of the cribs) this air could be sufficient for complete combusion of the fuel gases and the flame length was then apparently determined by mixing processes within the layer. When this air was not sufficient, the remaining air for combustion was entrained vertically into the horizontal layer from the cool air beneath and the flames became much longer.

Correlations of lengths of horizontal flames beneath non-combustible ceilings have been derived and related to the much shorter lengths of vertical flames. Relationships have been derived from the experimental data from which it is possible to estimate the radiation downwards from a hot non-combustible ceiling and the gases beneath it to the floor with a view to estimating the contribution to fire spread on the floor. A heat balance of the ceiling gases was satisfactory, so confirming the validity of the calculations. Horizontal flames radiate more of the heat produced at a level sufficient to assist fire spread than do vertical ones.

A combustible ceiling lining results in longer flames, an increase in the distance over which heat radiated downwards at an intensity sufficient to promote fire spread and a faster rate of increase of radiation than a non-combustible one with similar thermal constants.

The aspect of performance which best related to the results of BS 476 tests was the rate of increase of radiation downwards in the early part of the experiments. The radiation downwards was apparently partly determined by extraneous factors such as the detachment of the board from its holding nails and whether the decomposition products were emitted as jets.

The rate of spread of fire along a narrow strip of wood on the floor beneath a burning ceiling lining has been calculated and the results related to the index of performance on the Fire Propagation Test.     

Thermal characteristics of fires in a combustible corner

Three full-scale fire tests were performed with an area initiating fire in a combustible lined corner with a ceiling. In each of the three tests, the mock corner was lined with a different combustible material, plywood and two different composite materials. The area initiating fire was one of the ISO 9705 recommended standard ignition sources, a 0.17 m square propane sand burner with a heat release of 100 kW for 10 min followed by 300 kW for 10 min. Measurements of flame fronts, surface temperature, gas temperature, total heat flux, and total heat release rate were made during each of these tests. Heat flux and gas temperature data were found to be well represented by correlations developed from noncombustible fire tests.     

Fire Performance Properties of Solid Wood and Lignocellulose-Plastic Composite Deck Boards

Traditionally fire performance properties of externally located deck boards have been characterized by their flame spread index (FSI) as determined by UL 723/ASTM E 84. In this test a nominal 0.6 m wide by 7.3 m long array of deck boards is exposed to an approximately 90 kW ignition source fire for 10 min in the Steiner Tunnel. More recently the University of California Forest Products Laboratory developed a new fire test protocol based the principles of oxygen consumption calorimetry, California SFM 12-7A-4, Part A: Under-Deck Flame Test. This protocol addresses the potential ignition of a deck from underneath as may occur during a wildfire. In this protocol a nominal 0.44 square meter deck-system of deck boards mechanically fastened to wood joists is subjected to an 80 kW ignition source fire for 3 min. For this study the fire performance characteristics of more than thirty-five deck board types were evaluated by the above two methods and by a smaller-scale material-based test, ASTM E 1354 cone calorimeter. Deck boards were selected to represent a range of materials (untreated wood, lignocellulose-polymer composite), structures (solid, voided, microcellular foam), and cross-sectional profiles (width, thickness, presence of hidden fastener system longitudinal edge grooves). The results from this study were used to: 1. Develop correlations for deck boards between the material-based cone calorimeter tests and system-based under-deck tests. 2. Develop correlations for deck boards between the small-scale cone calorimeter tests and large-scale Steiner Tunnel tests. 3. Estimate the significance of ASTM D 2898 Method A accelerated weathering on fire performance.     

相对风速对高铁车厢火灾烟流及温度分布的影响

为探究相对风速对高速列车车厢火灾烟流及温度分布的影响,利用PyroSim建立我国复兴号某型二等座车厢火灾数值计算模型。在着火后3 min关闭外端门条件下,研究车窗破裂状态及不同的相对风速对车厢火灾烟流及温度分布的影响,评估火灾作用下高架桥列车运行的安全性。结果表明：对于人为砸碎应急逃生窗的情况,无论是形成单侧开口还是对流开口,对客室内部整体温度没有明显影响,火灾初期车厢火势主要向逃生窗破裂一侧蔓延;随着相对风速的增加,车厢走道温度降低,烟气抵达两侧客室端门的时间延长;在火灾初期,相对风速的增加对两侧通过台的冷却和排烟作用较为明显,缩小了危险区的范围;50 s前火源点附近很小范围为轻危险区,大致在（-2,2） m,车厢走道大多处在安全区,是人员逃生的最佳时段,综合考虑人员疏散及火势的蔓延情况,提出列车车厢发生火灾后安全运行速度为40 km/h。     

An engineering tool to calculate heat release rates of multiple objects in underground structures

Simple theoretical calculations of the overall heat release rate (HRR) of multiple objects have been carried out. The results were compared to fire experiments in a model tunnel using wood cribs placed at equal distances from each other. Three different methods are presented which are based on physical relations for fire spread between the wood cribs. The first method uses a critical heat flux as ignition criteria while the other two methods use an ignition temperature. The method using the critical heat flux as ignition criteria shows very good agreement with the corresponding experimental results used. The two methods using the ignition temperature as ignition criteria did not agree well with the corresponding experimental results. The prerequisites, that the methods should be kept relatively simple to be of practical use and that the burning objects should not necessarily have to be of uniform composition, were fulfilled.     

Influence of fire ignition locations on the actuation of smoke detectors and wet-type sprinklers in a furnished office

Experiments were conducted in a full-scale model office equipped with movable and fixed fire loads to explore the influence of ignition source (movable fire load(s)) conditions on smoke detector and sprinkler actuation. The interior plan dimension is 5.7 m × 4.7 m and the net ceiling height is 3.3 m. Both northeast and southeast wings have a 2.1 m × 0.9 m single door to be opened. Seven fire scenarios (seven different ignited fire load configurations) under natural ventilation were investigated experimentally. The results show that the amount of fire load at the initial stage in a room fire does not markedly affect smoke generation and does not significantly impact the actuation time of the smoke detectors. When the fire source is located near a corner, the plume corner effect greatly increases; smoke detectors and sprinklers can activate quickly and effectively actuate the fire suppression. When the fire source is located in the room's center, given the uncertainty regarding smoke detector and sprinkler actuation, it may not be possible to control the fire spread.     

Models for calculating flame spread on wall lining materials and the resulting heat release rate in a room

An extensive research programme, dealing with fire growth on combustible wall lining materials, has been ongoing in Sweden over the last decade. Several lining materials were tested in bench-scale fire tests in order to derive basic material flammability parameters. The same materials were also tested in a full scale room test and a 1/3 scale room test for two different scenarios, A and B. Scenario A refers to the case where walls and ceiling are covered by the lining material, Scenario B where lining materials are mounted on walls only.

This study utilises the results from these experiments and presents a mathematical model where material properties derived from standardised bench-scale tests are used as input data. The model predicts fire growth in the full- or 1/3 scale tests, in two different scenarios (A and B), and consists of sub-models for calculating the rate of heat release, gas temperatures, radiation to walls, wall surface temperatures and flame spread on the wall lining material.

A thermal theory of wind-aided flame spread on thick solids is examined and solutions are given and analysed for flame spread velocities under ceilings. Both numerical and analytical solutions are discussed.

The analytical solutions can be used to evaluate the flame spread propensity of materials and thus, whether a certain material is likely to go to flashover or not in the Room Corner Test. More generally, the solutions can be used to estimate whether a material will spread flame in a variety of concurrent flow flame spread scenarios. Results from the analytical solutions are compared with experimental flashover data for 22 materials, showing a good agreement.

The numerical solutions are incorporated into a simple room fire model. The results from the numerical model are compared with experiments on 22 materials tested in the full scale room for Scenario A. Comparisons for Scenario B are made with 10 materials tested in the 1/3 scale room. The results show reasonably good agreement for most materials between the model and the experiments.     

电缆表面温度对电弧引燃电缆及火焰蔓延影响

采用雅各布天梯电弧作为火源,通过加热器控制电缆表面温度,构建了电弧引燃110 kV电压等级的交联聚乙烯电缆实验平台,研究了电弧特性、电缆引燃及火焰蔓延过程.其中,电弧的维持电压幅值为3 kV,电流幅值为0.13 A,电弧气体温度为2000 K.保持电弧火源不变,结合电弧引燃电缆实验与火灾动力学模拟结果,发现随着电缆表面...     

110 kV高压电缆着火过程数值模拟研究

为了研究综合管廊局部空间内电缆接头内热源作用下的着火过程,通过运用数值模拟软件FDS三维传热和热解模型对110 kV高压电缆接头着火过程建模分析.研究了内外热源对电缆着火过程的不同影响,分析了不同运行状态下的温度分布情况,对比了不同缆芯材料的热传导作用对电缆着火过程的影响.结果表明,正常运行和短时过载状态下,电缆的火灾...     

A small-world network model for the simulation of fire spread onboard naval vessels

This work is devoted to the development of a small-world network model to predict real-time fire spread onboard naval vessels. This model takes into account short-range and long-range connections between neighboring and remote network compartments. Fire ignition and flashover, as well as fire transmissions through the walls and ventilation ducts are simulated using time-dependent normal probability density functions. Mean durations of fire transmission through the walls and ducts are determined by a three-zone model and a one-dimensional CFD code, respectively. Specific experiments are conducted in a steel room, representative of a naval vessel compartment, in order to validate the zone model. Then a proof of concept is developed by applying the network model to a full-scale vessel mockup composed of 113 compartments on 7 decks. A statistical study is conducted to produce fire risk maps, classifying the vessel compartments according to their propensity to burn.     

FEP 通信电缆燃烧性能试验研究

利用FIPEC 试验装置对FEP 通信电缆的燃烧特性进行了全尺寸试验研究。通过测试通信电缆在燃烧过程中的热释放速率、产烟速率、燃烧增长速率指数及火焰蔓延距离等参数研究其火焰蔓延情况,同时对影响电缆火焰蔓延的因素进行了分析。研究发现：点火源功率对FEP 通信电缆的火焰蔓延影响较小;电缆的排列方式和热边界条件是其影响FEP 通信电缆火焰蔓延的重要因素。同火源功率下,间隔排列比接触排列的火焰蔓延速度更快,其火灾危险性要大;同火源功率下,在钢梯后增加不燃背板比未加背板安装的火焰蔓延速度要快的多,其火灾危险性要大得多;FEP 通信电缆燃烧性能可达到GB 31247-2014《电缆及光缆燃烧性能分级》的B1 级。