狭长地下受限空间火灾分区形成的试验研究

通过狭长地下受限空间的火灾模拟试验,研究O#柴油在不同空间尺度形成的火灾分区现象.分析柴油燃烧时狭长地下受限空间火灾分区现象形成的判断依据、条件、时间,惰化区氧气耗量与空间容积的关系,惰化区氧气体积分数、烟气温度随时间的变化.结果表明.燃料量、空间尺度和燃烧表面积是影响狭长地下受限空间火灾分区形成的主要因素;分区现象形成的判断依据为惰化区氧气体积分数≤16%;分区现象形成的条件为火焰区容积热强度≥720 kW·m-3.这对地下受限空间火灾的防治和其性能化设计具有参考价值.     

扑灭矿井火灾的新装置──介绍DQ系列惰气灭火装置及其应用

今年5月,黑龙江省鸡西矿务局小恒山矿井下发生火灾,造成特大伤亡事故。对这样的大火有无快速有效的灭火装置呢?笔者愿给读者介绍一种这样的装置。 十多年来,世界各主要产煤国家在利用惰气灭火、抑制瓦斯爆炸方面取得了进展和成效。目前,矿井常用的惰气有液氮和燃气(是燃油除氧制取惰气的学名)。 惰气灭火,就是利用惰性气体的窒息性能,抑制可燃物质(包括可燃气体)的燃烧、爆炸或阴燃。它的主要优点有:(1)稀释火灾区域内空气的氧含量和可燃成分的含量,从而使火区惰性化,既能扑灭火灾,又能抑制瓦斯爆炸。(2)由于惰气分子直径小,容易穿过冒落区…     

地下复杂组合受限空间火灾分区现象与初期模式实验研究

主要介绍地下狭长与组合受限空间油料介质火灾分区现象、初期火灾主要模式模拟实验研究结果与讨论;地下组合受限空间火灾呈现出特殊的分区现象。一般可分为燃烧区、新鲜空气补充区、烟气流区、过渡区和火焰后面的“惰化区”五区。有上下两层的地下复杂组合受限空间可分为燃烧区、烟气流区、新鲜空气补充区和“惰化区”4区。地下受限空间(包括组合受限空间、容积式受限空间和狭长受限空间)密闭条件下火灾初期模式主要有：爆炸、爆炸减弱、爆炸增强、燃烧、爆燃向爆轰发展。地下复杂组合受限空间下部与下部狭长受限空间分别全开口条件下着火后火灾主要模式为爆炸、燃烧、爆炸后持续燃烧、爆炸后短时燃烧、爆炸后发展为出口外爆炸;爆炸又可分为爆炸强度逐步加强、爆炸由爆燃发展为爆轰、爆炸强度逐步减弱。     

煤燃烧特性热重试验研究及动力学分析

为了研究煤样挥发分、氧化程度及燃烧时氧气浓度对煤样燃烧难易程度的影响,设计并完成有关相应影响因素的3组热重分析(TGA)试验。采用等转化率法和特征温度分析法进行数据分析。结果表明:特征温度法显示煤燃烧时高挥发分煤样的特征温度较其他煤样低;等转化率法显示高挥发分煤样的各转化率下活化能也均低于其他煤样。2种方法的分析结果一致,都显示挥发分含量高的煤样较其他煤样易于燃烧。分析不同氧化程度下的煤样燃烧热重曲线和不同燃烧时氧浓度情况下的热重曲线得出,氧化程度越高,燃烧时氧浓度越高,煤越早开始燃烧,燃烧速度也越快。     

火灾节流过程参数变化时序及其影响因素的研究

巷道火灾节流过程中各物理参数变化时序是正确模拟非稳态火灾过程和救灾决策的基础。通过实际规模的火灾试验,三维布点,自动采集数据。研究揭示:节流发生的时段为着火初期燃料挥发分的快速释放和燃烧的数分钟以内;此时,烟温小于330℃,升温速率为138℃/min,耗氧速率为3.4%/min,阻力的响应速率为8.5Pa/min;着火分支节流函数的最小值为0.83,其入口风速滞后下降速率为1.67×10-3m/s2;温度峰滞后于氧气浓度谷点、节流函数最小点和阻力峰的时间分别为1.6min,4.2min和5.6min,使用温度峰值计算最大阻力的传统方法是错误的。提出了描述节流度的定量方法,并导出了影响节流效应的因素为系统和风机特性参数、火灾发生的位置、比燃料消耗速率、火风压和热阻的方向及增长速率。     

下行风流火灾管道试验与烟流动力特征研究

为了明确矿井巷道通风量及角度变化对火灾的影响规律，运用矿井火灾管道试验平台及各种传感器数据采集系统，开展下行通风火灾的管道相似模拟试验，得到在不同通风机动力和巷道倾角下巷道风量、各测点温度随时间的变化规律，对下行风流火灾时的风流紊乱状态有了进一步认识。结果表明，火灾时燃烧温度迅速到达顶峰后温度衰减速度随风量增大而加快，巷道火灾高温区域随着巷道风速增大而向火源下风侧移动。增大巷道倾斜角度，火风压作用增强，通风系统稳定性降低，更容易发生烟流逆退现象。在下行通风试验中，存在一个使火风压与通风机动力大小相等方向相反的临界风速。矿井火灾烟流是否产生逆退现象与通风能力有关，通风能力越强，巷道风流克服火区阻力、保持原状态的能力越强。     

扑救气体火灾应注意的问题

在一般情况下 ,一旦发生火灾 ,首先扑灭火焰 ,这似乎是天经地义的道理 ,但对有些火灾却不能这样做。比如可燃气体从容器、管道中泄漏而引起的火灾 ,没有绝对把握消除气体泄漏之前 ,就不能轻易将火扑灭。气体火灾通常具有这样一些特点 :第一 ,火灾发展没有阶段性 ,爆炸或燃烧一瞬间就会波及很大面积 ,并迅速扩大蔓延 ;第二 ,火势的发展往往由大变小 ,即由气体扩散区的大片燃烧 ,很快缩小到泄漏处的稳定性燃烧 ,这时一般不会有很大的危险 ;第三 ,燃烧值大 ,温度高 ,容易复燃 ,造成二次事故。根据以上特点 ,扑救气体火灾应注意以下两点 :一、气…     

R290制冷剂惰化燃爆特性实验研究

为了研究R290制冷剂惰化燃爆特性,采用带搅拌功能和氧浓度在线测定的20L球试验装置,对R290制冷剂进行了极限氧浓度测定。实验测定了丙烷在CO2和N2惰化气氛中的爆炸极限及极限空气浓度LAC,确定丙烷的极限氧浓度LOC;采用三元图爆炸区、丙烷-O2二维图爆炸区和ASTM标准分布图分析了混合气体爆炸区边界的燃爆特征,给出了极限氧浓度的确定方法和边界爆炸压力分布规律。实验结果表明:常温常压下R290的爆炸极限为2.1%～9.6%,CO2惰化气氛中的极限氧浓度为13.3%,对应的丙烷浓度为3.3%;N2惰化气氛中的极限氧浓度为10.8%,对应的丙烷浓度为2.7%。通过对比分析不同CO2和N2浓度下的爆炸区分布特征,表明CO2对丙烷的惰化效果要优于N2,以氮气和二氧化氮体积分数比为1∶2测试惰化气氛保护能力,惰化效果介于同浓度单种惰性气体之间。     

火旋风环境中飞火颗粒的上升行为研究

将火旋风流场分为火焰区和羽流区,采用数值模拟方法建立了球形飞火颗粒在火旋风火焰区和羽流区的上升轨迹模型.模型结合颗粒动力学方程和燃烧模型,模拟了飞火颗粒在火旋风环境中的上升行为,提出了飞火颗粒在火旋风流场中上升的临界条件,建立了飞火颗粒在竖直方向上升轨迹的计算方法.结果表明,在火旋风中能够上升的飞火颗粒的直径和密度之积应小于临界值,燃烧对于颗粒的上升行为有很大影响.相对于不燃烧颗粒,燃烧颗粒上升更高,速度更快.     

通风对综合管廊内电缆燃烧及火蔓延过程影响的数值模拟研究

综合管廊内电缆的火灾燃烧特性一直被国内外学者所关注,然而目前关于通风对电缆燃烧及火蔓延过程影响的研究相对较少。在通风系统的作用下,电缆内部及外部温度分布、热解气体浓度与无通风情况相比有很大的差异,电缆的燃烧及火蔓延过程将会更为复杂。为了研究通风作用下综合管廊内单根电缆的燃烧过程,采用FDS对15 kV交联聚乙烯绝缘铜芯电缆的火蔓延过程开展了数值模拟。通过分析不同风速条件下的电缆火焰形态、各层材料温度、火蔓延长度和热释放速率(HRR)曲线,详细研究了通风速度对综合管廊内单根电缆燃烧及火蔓延过程的影响。结果表明当通风速度不超过2 m/s时,通风能够促进电缆燃烧,电缆表面存在气相火焰,其火蔓延长度、热释放速率峰值等不断增加,此时综合管廊内火灾危险性不断增大;当风速大于等于3 m/s时,通风抑制了电缆燃烧,电缆的火蔓延长度、热释放速率峰值随之迅速降低,电缆PVC层、XLPE层温升的原因是线芯对绝缘材料的热传导,电缆的火灾危险性也随之减小。     

Trends in occupational hygiene in Finland

The aim of this work is to evaluate and describe the current status of, and prospects for, the future of occupational hygiene in Finland. The main sources of information include a seminar held in the annual meeting of Finnish Occupational Hygiene Society and interviews with different stakeholders. Nanotechnology and other new materials, changing work environments, circular economy including green jobs, new medical methods and advances of construction methods were recognized as future challenges. Future work opportunities for occupational hygiene experts included exposure assessments in indoor air surveys, private consulting and entrepreneurship in general, international activities and product safety issues. Unclear topics needing more attention in the future were thought to be in new exposures, sensitive persons, combined effects, skin exposures and applicability of personal protective equipment. Occupational hygiene should broaden its view; occupational hygienists should have to cooperate with other specialists and grasp new challenges.     

Gender differences in DUI offenders in treatment in Texas

OBJECTIVE: This is a study of 8,464 adult women and 21,155 adult males who entered substance abuse treatment in Texas between 2000 and 2005. Participants were either on probation for driving under the influence (DUI), were referred to treatment by DUI probation, or had been arrested for DUI in the past year. METHODS: The female and male clients were compared on demographic characteristics, substance use patterns, DSM-IV diagnoses, and levels of impairment. T tests and chi square tests were used to determine significance and multivariate logistic regression identified predictors of completing treatment and being abstinent at follow-up. RESULTS: The proportion of females who were sent to treatment as a result of DUI increased from 27% in 2000 to 32% in 2005. Females were significantly more likely than males to be White (73% vs. 56%), to have used substances a shorter period of time (17 vs. 19 years), to be seeking custody to regain their children (11% vs. 2%), to meet the DSM criteria for drug dependence (32% vs. 23%), to have injected drugs (31% vs. 23%), to have used substances daily (42% vs. 40%), to have a depressive disorder (16% vs. 7%) or bipolar disorder (12% vs. 5%), and to be have been in treatment before (60% vs. 49%). In contrast, males were more likely to be alcohol dependent (49% vs. 44%). Females were less likely to complete treatment (67% vs. 72%) and reported significantly more days of problems on the 6 domains of the ASI at both admission and at 60-day follow-up. Furthermore, at follow-up, they were more likely to be living with someone who abused alcohol or used drugs (9% vs.7%). CONCLUSIONS: Although females comprised only 29% of the DUI treatment admissions, they were more impaired and experienced more problems than their male counterparts. The findings indicate that additional resources, including treatment for co-occurring mental health problems and living in sober households, may be keys to helping these women achieve abstinence and prevent additional DUI episodes.     

我国非煤矿山安全生产的差距

从我国非煤矿山安全生产立法、安全生产管理体制、监察执法、群众监督、宣传教育、科研、矿山企业等方面与国外矿业进行了对比分析，分析了我国非煤矿山存在的问题以及与国外的差距，最后分析了产生问题与差距的原因。     

Trends in occupational injuries and fatality in Turkey

Introduction. The aim of this study was to evaluate the trend of occupational injuries in Turkey using epidemiologic criteria such as incidence mortality and fatality/all injuries recorded – rates. Materials and methods. Safety and health data were obtained from the Annual Statistic Books of the Social Insurance Institution (1988–2006) and Social Security Institution (2007–2011) of Turkey. Results. The results from the official data showed that although total employment is increasing the number of occupational injuries and incidence and mortality rates are decreasing. The results also demonstrate that occupational fatality/all injuries recorded – rate is increasing. The fatality/all injuries recorded – rate per 1000 injuries increased to 25.5 in 2011 from 8.6 in 1988. Each work day an average of five people died because of occupational injuries. Discussion and conclusions. The fatality/all injuries recorded – rate (the number of fatal cases per 1000 occupational injuries) is an important indicator of the injury rate for a country. Systems of occupational injury and illness surveillance constitute a critical resource for the management and reduction of occupational injuries and illness.     

Trends in chemical hazards in Japan

In the past, the chemical industry in Japan has been the cause of a number of major industrial accidents. Subsequent to each accident, specific lessons have been learned. These lessons learned have been implemented in terms of safety education of the employees and/or safety measures of the equipment and facilities resulting in a rapid decrease of corresponding accident frequencies. In this paper, we summarized both recent and past major accidents caused by chemical substances in fixed installations in Japan. Case studies show that runaway reactions are among the main causes of major accident occurrences in the chemical process industry in Japan. A recent fatal poisoning accident caused by H₂S gas generated during maintenance work again highlights the necessity of adequate safety management in a chemical factory. Therefore, even if hazard evaluation of chemical substances and chemical processes is necessary to prevent runaway reactions, human error is also an important factor contributing to reaction hazards [Wakakura, M. (1997) Human factor in chemical accidents, J. Safety Eng. High Press. Gas. Safety Inst. Japan, 34, 846].     

Violence in the workplaces in Finland

The aim of this study was to describe violence in Finnish workplaces by comparing it with leisure-time violence. The data were derived from 13,762 interviews made from a representative sample of the Finnish population in 1988. The subjects were asked to report all the violent incidents they had encountered during the previous 12 months. There were 394 victims of violence in workplaces, that is, 40.6 victims per 1,000 workers. The rate of occupational violence was almost identical for males (40.6) and females (40.5). The most hazardous occupations were prison guard, police officer, and mental health nurse. The main reasons for violence at work were related to refusal of an authority's order to go away or to the relationship between doctor or nurse and patient. A typical assailant was an unaccompanied man who was under the influence of alcohol.     

我国林区直升机吊桶灭火应用分析

直升机吊桶灭火是一项成熟有效的航空森林消防技术,是国外林业发达国家的重要森林消防手段。我国经过多年的探索和实践,已经在多数重点林区推广应用并取得成效。分析了直升机吊桶灭火的特点、机型和设备,对吊桶灭火的方法进行了探讨。     

Risk Assessment in the Working Environment in Estonia

The first step to chart hazards in the working environment in Estonia (labour force: 0.65 million) was taken by the National Board of Health Protection in the beginning of 1996.

The existing chemical, physical, and biological agents in the working environment were investigated with the help of local health inspectors in all counties. An identification of hazards and workers at risk was carried out. The results of the analysis showed that 16% of Estonian industrial workers are exposed to different hazards: 20,000 persons are exposed to noise, 11,000 are working in the conditions of vibration, 10,000 are affected by unsatisfactory microclimate, 6,000 complain about long-lasting work in a compulsory posture, the overexertion of eyes is suffered by 5,500 persons, and physical overload by 3,500 workers. In the group of chemical hazards the greatest numbers of workers are exposed to organic dust (6,500) and welding aerosols (5,400), followed by petroleum products (2,700), and oil-shale dust (4,300). The measurements of working conditions showed that an average of 30.3% of the results are above the standards. Proposals for the improvement of the situation in occupational safety and health are presented.     

我国化学品安全技术说明书(SDS)的管理现状研究

从分析我国化学品安全技术说明书的监管现状出发,研究对比了我国和国外在SDS覆盖化学品的范围、审核监督制度以及信息保密机制等管理技术方面的不同做法;指出我国对化学品安全技术说明书的监管在这三方面存在缺陷和不足;提出加强和完善化学品安全技术说明书的监管是提高我国化学品安全监管水平的重要手段;认为借鉴欧盟、美国和加拿大等国家的先进做法拓宽需要编制SDS的化学品范围、建立化学品安全技术说明书第三方检测制度、加强监督、完善信息保密机制将对促进我国的化学品安全监管水平具有重要意义。