木材阻燃处理工艺的现状及发展趋势

综述了目前国内外各类木材的阻燃处理方法，从阻燃剂的发展趋势以及木材对阻燃效果的要求分析了各种处理方法的优点及不足，并详细介绍了浸渍法等主要处理方法，归纳了木材阻燃处理方法的未来发展趋势。     

灭火试验用木垛燃烧特性研究

采用空白燃烧试验研究常用木垛引燃燃料的自身燃烧热释放规律,并采用油盘火引燃方式对自动灭火装置检测常用的小木垛进行了燃烧试验,获取了热释放速率及总放热量特性。以自动灭火装置和灭火药剂的应用特点和工作方式为出发点,采用四角点火方式对同类型木垛进行了引燃试验,对比分析两种点火方式所获得的燃烧热释放参数曲线规律和区别的产生原因。采用四角点火方式的木垛燃烧进程阶段性特征更为明显,适宜于考察自动灭火装置类产品对于初起火灾的反应和抑制效果,以及考察灭火药剂对木垛燃烧的最大扑灭能力。     

Wind effects on smoke motion and temperature of ventilation-controlled fire in a two-vent compartment

High-rise building fire is often influenced by the ambient wind. Study concerning fire behavior in the compartment of high-rise buildings in wind environment is needed for exploring some effective methods used for evaluation of compartment fire smoke movement and control. In this paper, smoke flowing direction and temperature of ventilation-controlled fire in a two-vent compartment are studied when ambient wind blows to the vent at higher altitude. It is found that there is a critical wind speed, above which the direction of smoke movement is dominated by wind rather than by buoyancy. It is also found that ambient wind has a complex influence on smoke temperature in the compartment. When wind speed exceeds another critical value, only one steady state appears in the smoke temperature rising curve. Otherwise three steady states appear. Heat transfer through the compartment walls has great influence on the second critical wind speed.     

Simulation of temperature and smoke distribution of a tunnel fire based on modifications of multi-layer zone model

Some modifications on Suzuki’s multi-layer zone model (MLZ) have been done to predict temperature and smoke distribution of a tunnel fires, i.e., the radiation heat loss of fire source is taken into account and a four-surface radiation heat transfer model is introduced. Like Suzuki’s model, as a special long and narrow space, the tunnel space is also divided into a number of layers in vertical direction and regions in longitudinal direction. The physical properties like temperature and species (CO, CO₂, etc.) are assumed uniform in every zone like two-zone model. However, the different heat transfer model is introduced. The MLZ model prediction is compared with the experiments of USTC and CFD model (FDS). It shows good agreement between the model prediction, experiments and CFD models (FDS). And the MLZ model needs less time than CFD model.     

Numerical simulations on fire spread and smoke movement in an underground car park

The Fire Dynamic Simulator code is used to investigate fire spread and smoke movement in a large underground car park under different fire scenarios. Initially, by comparing with experimental results of heat release rate of a single car fire, the development of car fire is designed by letting surface densities of the fuel over the car. Fire spread and movement of smoke are then investigated under different ventilation conditions. Simulated results show that the development of car fire in the underground car park can be classified into four stages; namely an initial stage, a developed stage, an extinction and re-burning stage and another fast-developed stage. Affected by ventilation systems, fire develops rapidly resulting in consuming most oxygen quickly followed by early extinction of the fire. After extinction of the fire, with more ambient air drawn into the car park due to ventilation, re-ignition takes place with accelerated development. In addition, detailed field distributions of temperature and velocity vectors are given. It is found that the smoke layer decent to the top of the car after 15 min and the hot smoke flows in a disorderly manner resulting in the spread of fire more rapidly.     

风电火灾原因及防火对策

通过对风能特点与消防关系的分析,找出引发风电火灾的原因,如雷击、电气、机械故障、人为因素等,提出增设固定报警灭火系统、防火分隔控制、加强消防技术研究、制定相关标准、加强日常防火监督等预防风电火灾的对策.     

Flame and smoke detection method for early real-time detection of a tunnel fire

This paper presents an image-processing technique for automatic real-time flame and smoke detection in a tunnel environment. To avoid the large-scale damage caused by fire occurring in different environments, there are many studies about discovering and minimizing an incident as fast as possible. However, we need an original algorithm specialized for a tunnel fire, because this environment is quite different and it is difficult to apply existing fire detection algorithms to a tunnel environment. Therefore, this paper proposes an original algorithm that applies to a tunnel environment. Color and motion information are used to minimize false detections in tunnels, and this information enables us to detect the exact position of an event at an early stage, by detection, test, and verification procedures. The experimental results show the validity and efficiency of the proposed algorithms by a comparison of the characteristics of each algorithm.     

屏蔽门对地铁火灾烟气流动的影响分析

针对某地铁双层岛式车站,利用FDS模拟研究无屏蔽门和有屏蔽门两种情况发生火灾的场景,分析温度和烟气浓度分布,并对结果进行比较分析。结果表明,屏蔽门对于火灾烟气的扩散有显著的抑制作用,对地铁站台设计、火灾时人员疏散等具有一定的理论指导。     

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.     

Measurements of gas velocities and temperatures in a large open pool fire

A number of measurements were made to help define the thermal and flow conditions in a 9 × 18 meter pool fire that was used to simulate a transportation accident. Temperatures were measured at twenty-eight locations throughout the continuous flame region. Velocities were measured at four vertical stations near the centerline of the pool. Heat fluxes were estimated from thermal measurements on and near vertical steel plates. As is often the case in fires of this size, the effects of mild, ambient winds on the measurements were pronounced. Attempts have been made to mitigate these effects by the application of conditional sampling. Temperatures and velocities are compared with other experimental results as well as results of modeling efforts.     

不同类型火源下烟气在大空间内的充填特性研究

在大空间火灾试验厅内采用沙发作为火源，研究了烟气层的发展过程，并将得出的烟气层温度、烟气层下降曲线与油池火对比。结果表明：不同的火源条件下，烟气的温升曲线和烟气层下降曲线是不同的，对于稳定的油池火，烟气层下降曲线是光滑的，对于非稳定火源，烟气层下降曲线存在跳变现象；烟气层厚度较小时，火源热释放速率的大小对烟气层的温度、烟气层的下降速率有着重要影响；对于变热释放速率情况下的烟气充填，可以采用对热释放速率的分段近似来进行模拟分析。     

建筑幕墙防火材料选择及防火要点

本文主要对建筑幕墙的防火材料的使用,建筑材料及其制品燃烧性能分级,常用防火、保温材料燃烧性能等级,幕墙防火设计的相关规定,幕墙防火设计及施工要点进行了简述。     

外墙外保温材料的火灾危险性研究及防火对策

针对目前国内外外墙外保温材料的应用现状,分析了外墙外保温材料的火灾危险性,从技术方面、管理方面、标准制定方面、消防宣传教育方面提出防范对策,为今后外墙外保温材料的进一步推广使用提出合理化建议。     

碳酸钾与硅溶胶复合对木材阻燃改性研究

为获得一种具有良好抑烟性能与抗流失性能的环保型木材阻燃剂,采用K2CO3与SiO2溶胶对杉木试件进行二次加压浸注处理,制得K2CO3/SiO2/木材无机质复合木材.采用锥形量热仪法(CONE)测试其阻燃性能,并测试了其抗流失性能.结果表明,杉木试件经K2CO3/SiO2复合处理后,点燃时间较未处理试件延长1倍左右,热释放速率及总量下降30％左右,抑烟性能非常显著;K2CO3/SiO2/木材的抗浸提值达到53％左右,具有较好的抗流失性能.     

火灾试验用标准燃烧物的制备及燃烧特性

基于典型场所的火灾载荷密度及可燃物,制备了典型的塑料杯组合体和纸杯组合体标准燃烧物,开展两种标准燃烧物的燃烧特性试验研究.结果表明,两种典型的标准燃烧物的燃烧性能稳定,总热值、火灾增长速率数据偏差较小,实验的重现性良好;在一定条件下,塑料杯组合体标准燃烧物可近似代表火灾载荷约为157.8 MJ的近中速火,纸杯组合体标准燃烧物可近似代表火灾载荷约为51.1 MJ的慢速火.     

挡烟垂壁与排烟口设置对烟气层高度的影响

通过N百分比法,理论计算得到了挡烟垂壁与排烟口设置对商业建筑内相邻防火分区烟气层高度变化的影响.分析结果发现,挡烟垂壁凸出越多,烟气层下降速率更为缓慢,后期烟气层高度越高;排烟口距离火源越近,后期烟气层高度越高;排烟口朝向对烟气层高度的变化影响不大.     

Effect of fire retardants on internal bond strength and bond durability of structural fiberboard

This study evaluated the effect of a number of chemicals on the internal bond (IB) strength and bond durability of phenolic-bonded structural fiberboard (medium density fiberboard) panels. Borax (BX), boric acid (BA), monoammonium phosphate (MAP), diammonium phosphate (DAP), and phosphoric acid (PA) were sprayed onto the fibers made from 50% pine (Pinus nigra Arnold var. pallasiana) and 50% beech (Fagus orientalis Lipsky) woods at 2%, 4%, and 6% retention levels based on oven-dry fiber weight. The panels were tested for unaged IB strength (dry), and IB strength (aged), after cyclic-accelerated aging, according to the procedures defined by European Norm (DIN EN) 321 (1999). Unaged IB and aged IB values of all the treated specimens at three retention levels were significantly decreased when compared to untreated control values. The IB strength and bond durability of all the treated panels decreased with increasing chemical content. BX-treated specimens had the best IB strength and bond durability, followed by DAP-, MAP-, BA-, and PA-treated specimens, respectively.     

高层建筑外墙保温材料火灾危险性解析及控制

通过对外墙外保温材料的概述,分析了高层建筑外墙保温材料的火灾危险性,并根据相关设计规范,制定了三方面的控制措施,以期杜绝外墙保温系统起火事故的再次发生。     

铝木复合耐火窗窗框阻燃性能研究

为提高铝木复合窗的耐火性能,对木材阻燃性能进行研究。以热释放速率、热释放总量、总产烟量和质量损失为评价指标,对比了阻燃剂浸泡时间、木材种类和阻燃剂种类对木材燃烧性能的影响。试验结果表明,木材在阻燃剂中浸泡时间越长,其阻燃效果越明显;樟子松由于载药量大,后期燃烧性能更好;经阻燃剂6505浸泡后的木材综合性能较好,可作为后续耐火窗生产的备选阻燃剂之一。     

Effects of environmental tobacco smoke on respiratory health of boys and girls from kindergarten: results from 15 districts of northern China

The effects of childhood environmental tobacco smoke (ETS) exposure on respiratory symptoms were investigated in 6053 kindergarten-aged children residing in 15 districts of northern China. Responses to a self-administered questionnaire completed by parents of children from 30 kindergartens were used to ascertain children with persistent cough, persistent phlegm, asthma symptom, current asthma, wheeze and wheeze without asthma. In first 2 years ETS exposure and current ETS exposure were associated with increased prevalence of persistent cough, persistent phlegm, wheeze and wheeze without asthma. Among boys, ETS exposure was associated with more respiratory symptoms and diseases than in girls. ETS exposure during pregnancy was associated with asthma symptom [odds ratio (OR), 3.00; 95% confidence interval (CI): 1.28-7.03], current asthma (OR, 3.38; 95% CI: 1.25-9.14), persistent cough (OR, 1.64; 95% CI: 1.13-2.37), persistent phlegm (OR, 1.74; 95% CI: 1.01-3.01), wheeze (OR, 1.75; 95% CI: 1.15-2.68), and wheeze without asthma (OR, 1.46; 95% CI: 1.01-2.37) only among boys. In boys, the adjusted ORs for increased risk of asthma symptom and current asthma for household exposures (> or =10 cigarettes smoked per day vs. none smoked) during workday were 2.04 (95% CI: 1.01-3.89) and 2.76 (95% CI: 1.06-9.58), respectively. We conclude that ETS exposure increases the occurrence of respiratory symptoms and diseases during childhood. Boys may be more susceptible to ETS than girls. PRACTICAL IMPLICATIONS: Environmental tobacco smoke (ETS) is a highly prevalent respiratory irritant. In agreement with previous cross-sectional studies, our study indicates that exposure to ETS may increase the occurrence of respiratory symptoms and diseases in children, and the association of ETS exposure and respiratory health of children increased in strength with number of cigarettes smoked inside the house per day during workday and day-off. Boys may be more susceptible to ETS than girls. These findings support the view that measures should be taken to reduce ETS exposure for children.