UN test O.1 errors in quantifying the behavior of solid oxidizers

The results of the UN test O.1 for oxidizing solids are shown to be incorrect when specimens contain certain inertant additives, illustrated for the case of oxidizers in the ammonium nitrate fertilizer family. Test results for three different AN-based products containing inertants show that two of the three (including calcium ammonium nitrate, CAN, a long-known safer alternative to AN) would be misranked with the O.1 test. An analogy between the heat release rate of substances containing fire retardant (FR) chemicals is established and several ways by which FR behavior can be achieved are demonstrated. It is shown that the O.1 test implicitly adopts only one model of inertant action, and that chemicals which rely on a differing mode of inertant action are liable to be incorrectly treated. It is further shown that the physical basis of the O.1 test—an intimate mixture of finely-comminuted fuel and oxidizer—misrepresents the most common type of accidents involving oxidizers, and that such test results do not correspond to scenarios of a less extreme nature. The new O.3 test improves the analysis method, but does not resolve the problem of excessive commingling of fuel into oxidizer. It is recommended that the intermediate-scale arrangement used by the Bureau of Explosives be adopted for further development and standardization, in preference to the O.1 or O.3 test arrangements.     

二溴海因危险性试验研究

为评价二溴海因(简称DBDMH)在使用、储运过程中的危险性,采用75℃热稳定性试验对二溴海因在高热条件下的稳定性进行了研究,采用C600微量热法测试了二溴海因的放热起始温度、分解热,并依据《联合国关于危险货物运输的建议书-试验和标准手册》对其爆炸性进行了筛选,通过固体氧化性试验和家兔皮肤刺激性/腐蚀性试验分别对二溴海因的氧化性和皮肤刺激性进行了测试。结果表明:二溴海因在75℃热稳定性试验过程中没有出现着火或爆炸,未出现自加热迹象,不属于太不稳定不能运输的物质;其分解反应只有一步,起始反应温度大约为157℃,分解热为384.8J/g,不属于爆炸品;二溴海因具有氧化性,根据《联合国关于危险货物运输的建议书-规章范本》其包装级别为Ⅱ级;在家兔皮肤刺激性/腐蚀性试验中未见不可逆损伤,对皮肤具有强刺激性。     

Validation of the UN test method N.5

Many substances react with water in such a way that flammable gases are formed. For transport issues this reaction may possess a considerable hazard especially if the cargo is wetted by rain or by water from other sources. In the UN Recommendations on the Transport of Dangerous Goods these kinds of problems are addressed. The UN test N.5 “Test method for substances which in contact with water emit flammable gases” corresponds to this hazard. Classification according to the test method is done by measurement of the gas evolution rate of the flammable gas by any suitable procedure. At BAM a gravimetric approach is used to measure the gas evolution rate. In this paper we present the evaluation of the apparatus by means of an absolute calibration routine utilizing a reaction where a known amount of gas is produced as well as the evaluation of important parameters influencing the gas evolution rate using different substances. It can be shown that the apparatus is capable of measuring absolute gas volumes as low as 6 mL with an acceptable error of about 17% as determined from the reaction of Mg with demineralized water.     

Towards the improvement of UN N.5 test method for the characterization of substances which in contact with water emit flammable gases

This paper deals with a sensitivity analysis of main parameters affecting the measurement of the gas flowrate emitted during testing substances for their potential to emit flammables gases in dangerous quantities where in contact with water, according to the UN N.5 test procedure. UN N.5 is described in the Manual of Tests and Criteria of United Nations (part of the Orange Book) (ONU Manual of Test and Criteria, 2008), serving both applications of international transport regulations as well as classifications of dangerous substances according to Globally the Harmonized System (GHS) and the derived regulation applying in the EU known as “CLP” Regulation (Regulation (EC) No 1271/2008). The main reason that justifies the present research is that the measurement of emitted gases is highly critical in the final classification resulting from the interpretation of the test results. Moreover, that idea has been raised to adapt the UN N.5 test protocol for classifying, in the future, substances that by contact with water would emit dangerous quantities of toxic gases.Experiments have been carried out to cover the analysis of the influence of ambient temperature, overall volume of glassware, nature of aqueous media, mass sample and sample-to-liquid mass ratio, since such parameters are not fixed within any defined range in the UN N.5 test procedure. The influence of the flow rate measuring device was also considered. Results confirm that the above mentioned parameters may play a significant role to such an extent as to finally alter the final classification resulting from the testing. Guiding principles have also been derived from our measurements and observations towards an improved and more robust UN test protocol in the future.     

Comparison of calculated data for the flammability and the oxidation potential according to ISO 10156 with experimentally determined values

The classification of flammable gas mixtures is based on either testing or calculation methods proposed by the revised international standard ISO 10156. This standard is used for classification of physical hazards in Chapters 2.2 and 2.4 of the UN Globally Harmonized System of Classification and Labelling of Chemicals (GHS) and in the UN Recommendations on Transport of Dangerous Goods (TDG). The test methods of flammability and oxidizing potential in this standard were developed by BAM. Earlier versions of this standard are not based on triangular diagrams and on the reference combustible substance “ethane”. The old material characteristics, especially in case of oxidizing potential, are based mostly on practical experience without any quantifiable test results. First time it is possible to compare experimental results from the CHEMSAFE database with the newly developed calculation method. In this paper the basic principles of the calculation methods are presented and the methods are validated by examples. A comparison of experimental flammability data with classification results gained by the calculation methods of ISO 10156 is demonstrated.     

Disposal of hexachlorodisilane and its hydrolyzed deposits

Hexachlorodisilane (Si₂Cl₆, HCDS) is an important precursor used in semiconductor device manufacturing. It is a flammable as well as a water reactive liquid which hydrolyzes rapidly upon contact with water or moisture. The hydrolyzed deposits are also known to be shock-sensitive with explosion energy equivalent to trinitrotoluene (TNT). In this work, two phases of test program including disposal of HCDS and disposal of the shock sensitive HCDS hydrolyzed deposits were conducted. The first phase of the program was to find an agent that can completely dissolve/react the HCDS vapor without forming shock sensitive deposits. The second phase of the program attempted to find a suitable agent to suppress the Si–Si bonds, one of the essential roles of chemical functional groups in shock sensitivity of the HCDS hydrolyzed deposits to suppress the shock sensitivity. A variety of agents such as sulfuric acid solutions, aqueous sodium hydroxide (NaOH) solutions, aqueous potassium hydroxide (KOH) solutions, KOH/alcohol solutions were utilized as the suppressants in this work. Samples mixed with suppressants were not only tested for shock sensitivity by a Fall-hammer apparatus but also analyzed for chemical functional groups to identify the effect of each agent. Concentrated sulfuric acid was found to suppress the shock sensitivity of the liquid HCDS hydrolyzed deposits by acting as a medium that helps the hydrolyzed deposit to retain moisture. KOH/alcohol solutions can turn HCDS vapor into non-hazardous silica, so that, it provided a safe way to dispose HCDS. Finally, practical recommendations about handling and eliminating the risk of shock sensitivity are given for HCDS liquid spill, HCDS vapor vent and HCDS hydrolyzed deposits.     

The “Mini Closed Pressure Vessel Test (MCPVT)” as a screening or classification test for explosive properties of organic peroxides

Tests according to the UN Recommendations on the Transport of Dangerous Goods for the determination of explosive properties of organic peroxides have been compared with screening criteria for explosivity based on measurements in a closed mini-autoclave (MCPVT). It will be shown that an additional screening test may be helpful but the information obtained from the UN tests are more important to characterise the specific properties of a substance under different conditions.     

CEQAT-DGHS interlaboratory tests for chemical safety: Validation of laboratory test methods by determining the measurement uncertainty and probability of incorrect classification including so-called “Shark profiles”

Laboratory test results are of vital importance for correctly classifying and labelling chemicals as “hazardous” as defined in the UN Globally Harmonized System (GHS)/EC CLP Regulation or as “dangerous goods” as defined in the UN Recommendations on the Transport of Dangerous Goods. Interlaboratory tests play a decisive role in assessing the reliability of laboratory test results. Interlaboratory tests performed over the last 10 years have examined different laboratory test methods. After analysing the results of these interlaboratory tests, the following conclusions can be drawn:1There is a need for improvement and validation for all laboratory test methods examined.2To avoid any discrepancy concerning the classification and labelling of chemicals, the use of validated laboratory test methods should be state of the art, with the results accompanied by the measurement uncertainty and (if applicable) the probability of incorrect classification.This paper addresses the probability of correct/incorrect classification (for example, as dangerous goods) on the basis of the measurement deviation obtained from interlaboratory tests performed by the Centre for quality assurance for testing of dangerous goods and hazardous substances (CEQAT-DGHS) to validate laboratory test methods. This paper outlines typical results (e.g. so-called “Shark profiles” – the probability of incorrect classification as a function of the true value estimated from interlaboratory test data) as well as general conclusions and steps to be taken to guarantee that laboratory test results are fit for purpose and of high quality.     

Evaluative comparison of two methods for SADT determination (UN H.1 and H.4)

We present our results on the comparison of two methods for the SADT determination. Both methods, UN test H.1 and UN test H.4 are recommended by the international transport regulations from the UN. But during the last years the applicability of the UN test H.4 has been questioned for solid substances. Therefore, three organic peroxides and one self-reactive substance have been investigated in 5 kg and 20 kg packages as well as in the UN test H.4 in a 500 mL Dewar vessel. The SADT values determined with the different methods match. The UN test H.4 seems to be well suited for solid organic peroxides and self-reactive substances of at least 20 kg or 60 L.     

联合国建议的固体氧化物燃烧测试方法的研究

由于日本消防法中固体氧化物的燃烧试验方法,与联合国黄皮书中所建议的试验方法有所不同,在实际应用中经常出现矛盾.因此,本文对其中的一些不同之处进行了重新的研究考察.并与日本海事检定协会和代表联合国标准测试方法的荷兰应用科学研究组织进行合作,对比研究了联合国建议的关于固体氧化物燃烧试验的方法.并就其中发现的问题提出了相应的改进意见.具体有以下4方面的措施:(1)纤维素种类对于燃烧时间的影响;(2)环境湿度及纤维素含水量对燃烧时间的影响;(3)导火线材料与导火线破裂方式出现的问题;(4)联合国建议中的举例数据.     

Enhanced friction and shock sensitivities of hexachlorodisilane hydrolyzed deposit mixed with KOH

In this work, the effects of potassium hydroxide (KOH) on friction and shock sensitivity of the hexachlorodisialne hydrolysis products were studied. A wide range of KOH content, from 0.02 to 21.5 wt%, in the mixture of KOH and HCDS hydrolyzed deposit was prepared by mixing the deposit with aqueous KOH solution and dried in glovebox. The lowest impact energy (LIE) and lowest friction force (LFF) were determined by BAM fall-hammer and friction test apparatus, respectively. It was found that both shock and friction sensitivities increased with an increase in the KOH content in the HCDS hydrolyzed deposit. In particular, the LIE and LFF decrease from 6 J to 326 N of the original deposit to less than 0.125 J and 7 N for deposit with 0.03 and 0.3 wt% KOH. Differential scanning calorimetry studies showed that a new exothermic peak was observed between 80 °C and 150 °C which is also accompanied by evolution of hydrogen. It is proposed that, the presence of KOH results in the formation of Si–Si–OK groups leading to the weakening of the neighboring Si–Si bonds. Any mechanical impact or friction will lead to the cleavage of the unstable Si–Si bonds and subsequently initiate a fast chain oxidation of adjacent Si–Si and Si–OH bonds to form more Si–O–Si groups, releasing H₂ gas and heat. Recommendations were given for handling and disposing of these explosive deposits.     

对“安全驾驶适应性测验”的可行性研究

重点对“安全驾驶适应性测验”的信度和效度进行了研究和检验。通过对３１０ 名汽车驾驶员的答卷资料所处理结果表明：事故群驾驶员和非事故群驾驶员的心理品质差异主要表现在观察能力,判断能力,推断能力,辨别能力,思维的灵活性,注意的广度与稳定性,个性方面的安全驾驶态度,情绪的稳定性及是否过分自信等方面。另外,对年龄、文化程度、驾驶经验与事故率之间关系的考查表明,年龄与事故率之间的相关程度是十分显著的。说明该测验对于识别事故群驾驶员和非事故群驾驶员具有一定的区分性和预测性。     

可燃制冷剂空调用开关元件点燃危险及防爆试验分析

随着全球范围对环境问题的日益重视,R290,R32等新型制冷剂因优良的环保性能和节能效果被广泛应用于空调行业,但其属于IIA级爆炸性气体,为了进一步分析其运行过程中的防爆安全性能。通过文献数据和测试分析,可燃制冷剂空调电气元件的点燃源主要来自其工作过程中产生的电气火花。其中空调开关元件最容易产生电火花、电弧,且通过试验验证这些火花或电弧能点爆（6.5±0.5）%乙烯/空气混合物。综合IEC 60335-2-40,GB 4706.32标准要求和空调开关元件的结构特征,分析确定其应符合“nC”型防爆技术要求,并能通过“nC”型爆炸试验。针对开关元件结构尺寸小、存在爆炸试验中爆炸性混合气体多次置换和负载通、断电操作的难点问题,提出一套合理可行的爆炸试验实施方案,并通过测试应用得到验证。     

Complaints regarding occupational health and safety in the area of Thessaloniki (Greece)

This paper deals with the complaints regarding occupational health and safety in the area of Thessaloniki (Greece). It seeks to examine who are the complainers and which companies or activities do they complain about, to what extent are complaints relevant to occupational health and safety and whether the complaints result to penalties. Such complaints do not pertain to all economic sectors equally, nor do they derive from all kinds of sources. Furthermore, it appears that complaints “irrelevant” to occupational health and safety are twice as many as the “relevant” ones. In three quarters of the cases, the complaints do not result to any kind of sanction; more specifically, in one fifth of the cases, the complaints are not followed by any action taken by the office in charge. All things considered, it seems that filing complaints does not imply finding the most dangerous workplaces. Therefore, investigation of complaints should not be considered more significant than other inspection activities.     

Implicit attitudes towards risky driving behaviors: Evidence of validity for the implicit association test

Introduction: Attitudes toward risky driving behaviors are commonly evaluated through direct self-report measures. Nevertheless, these instruments have limitations, such as socially-desirable responding. This study examines the validity of the Implicit Association Test (IAT) as an indirect measure of attitudes towards risky driving. An IAT with “risky” vs. “safe” driving behaviors categories was evaluated. Method: A sample of 100 participants (ranging from 18 to 70 years of age) completed the IAT and measures of attitudes, driving styles, personality traits, risk-taking (IOWA Gambling Task), and social desirability (Driver Social Desirability Scale). Results: A high level of internal consistency was found for IAT scores. The IAT was correlated with driving styles (risky, dissociative, and careful dimensions), risk-related personality traits (impulsive/sensation seeking and aggression/hostility) and risk-taking measures. IAT scores were also associated with self-reported risky driving behaviors (r = 0.33). As expected, a higher level of negative implicit attitudes was found among young drivers. The driver social desirability scale was correlated with most self-report measures, but not with the IAT. Conclusion: The present study provides reliability and validity evidence for the IAT as an indirect measure of attitudes towards risky driving. The IAT can serve as an important complement to conventional self-report measures of driving attitudes. Practical Applications: Potential use of global measure of implicit attitudes toward risky driving behaviors in the evaluation, education, and training of drivers are discussed.     

The Relationship Between Critical Flicker Fusion Frequency (CFFF) and Temperamenta Characteristics

he analysis in this paper was based on data obtained from 80 male participants, aged 29-65. Critical Flicker Fusion Frequency (CFFF) was measured using the Flicker Test. The Formal Characteristics of Behaviour-Temperament Inventory (FCB-TI) by Strelau and Zawadzki (1993) was used for temperamental characteristics. The results of statistical analysis did not confirm a hypothesis about the correlation between CFFF level and 3 temperamental characteristics. There were no immediate relationships among those variables. Correlation was observed when the CFFF coefficient of variance, instead of average CFFF values, was taken into account, especially in the case of a division into 2 groups of participants, “reckless” and “unsure.” It could be interesting to check in the future a hypothesis about the stability of selected types of reactions.     

论本质安全

考查“本质安全”一词的出处 ;介绍了几种“本质安全”的论述 ;讨论了“以人为本”和“人本管理”与本质安全 ;从政治和哲学的高度 ,论述了政治、现象与本质的内涵与关系 ;探讨了美国及发达国家是否有“本质安全”;分析了现代资本家重视职业安全卫生的实质。笔者对以上问题阐明了自已的观点 ,并对一些提法给以评述。     

基于HFACS的化工企业火灾爆炸事故人因分析*

为研究化工企业火灾爆炸事故的主要人为因素,以63起火灾爆炸事故案例为样本,构建人为因素分析与分类系统（HFACS）模型,进行火灾爆炸事故人为因素分类统计与分析,并利用卡方检验和比值比分析HFACS模型上下层级间的因果关系。结果表明:HFACS模型中上下层级人为因素间存在显著的因果关系,层级1中的“不良的组织氛围”及“组织过程漏洞”和层级2中“监督不充分”在HFACS模型中可以显著增大事故发生的可能性,且“资源管理漏洞”、“不良的组织氛围”、“组织过程漏洞”→“监督不充分”→“人员因素”→“违规”是引发事故的关键路径,并根据HFACS模型中引发事故的关键路径及其人为因素的主要表现形式,提出针对性的化工企业火灾爆炸事故预防措施。     

水电工程高危作业风险影响因素的SEM模型

为探索水电工程高危作业的事故致因机理,耦联分析水电工程施工风险管理过程,从"施工企业影响"、"施工安全管理"、"施工人员行为"、"现场作业相关因素"等方面归纳总结水电工程施工事故风险要素及构成体系;在此基础上,通过问卷调查收集基础数据并定义研究变量属性,抽象风险与影响因素关系的概念模型,建立与检验高危作业风险的SEM模型;然后,以修正指数MI为判据,修正和优化SEM模型。研究结果表明:安全管理制度、教育培训、职业健康环境、个人决策能力对水电高危作业风险具有显著影响,是风险监管的重点,同时也启示风险管理者应深入贯彻"以人为本"的理念,加强"顶层制度设计"。     

Effectiveness of temporary traffic control measures in highway work zones

In the United States, hundreds of people lose their lives each year and many more are injured due to vehicle crashes in the work zones. Over the years, temporary traffic control (TCC) measures have been developed and deployed in work zones. To continuously improve the safety, there is a need to identify the traffic control deficiencies in work zones by evaluating the effectiveness of existing TTC measures based on the real crash cases. In this study, researchers evaluated the effectiveness of several commonly used TTC methods using logistic regression techniques and various significance test methods including likelihood ratio test, score test, and Wald test. These TTC methods included flagger/officer, stop sign/signal, flasher, no passing zone control, and pavement center/edge lines. A total of 655 severe crashes in Kansas highway work zones between January 2003 and December 2004 were used for the evaluation, which included 29 fatal crashes and 626 injury crashes. Results indicated that flagger, flasher, and pavement center/edge lines were effective in reducing the probability of causing fatalities when severe crashes occurred. In addition, using these devices could prevent some common human errors, such as “disregarded traffic control”, “inattentive driving”, “followed too closely”, and “exceeded speed limit or too fast for condition”, from causing severe crashes.