Aluminium dust explosion risk analysis in metal workings

The aim of this paper is to present a risk analysis method that can be applied to factories where combustible dust is handled, in the form of raw materials, products or by-products, and therefore at risk to explosion. The work was carried out on site: a consistent number of companies that deal with the surface finishing of objects in aluminium through grinding were examined. The aluminium powder produced as a by-product is generally captured by suction plants and then subjected to dry or wet type abatement. In order to provide a rational approach to the risk assessment and frequency estimation, each company was divided into the so-called fields of study; and four risk assessment topics were identified for each field. A brief review of the methods that are available for the consequence magnitude estimation, regarding both the pressure wave and the launching of missiles, is also provided.     

Uncertainty representation and propagation in quantified risk assessment using fuzzy sets

It is generally acknowledged that there are substantial uncertainties present in any analysis of risk. This paper provides a brief overview of the current techniques used for uncertainty analyses, and highlights their inappropriateness for practical use in the complete risk assessment process. The concept of fuzzy sets as a means for quantifying uncertainty is introduced and a case study demonstrates the application of this method to a simple consequence analysis where parameter uncertainty is considered. The results of this fuzzy analysis are compared with those of a more traditional probabilistic approach using a Monte Carlo simulation. This comparison demonstrates that the novel approach of fuzzy sets is a more appropriate technique due to its non-statistical nature and that the amount of computation required is substantially reduced compared to the traditional probabilistic approach. The versatility of fuzzy set theory suggests that this approach could also be used to quantify other types of uncertainty present in the risk assessment process, including model uncertainty and expert opinion.     

A criterion for developing credible accident scenarios for risk assessment

Maximum credible accident analysis is one of the most widely used concepts in risk assessment of chemical process industries. Central to this concept is the aspect of ‘credibility’ of envisaged accident scenarios. However, thus far the term credibility is mostly treated qualitatively, based on the subjective judgement of the concerned analysts. This causes wide variation in the results of the studies conducted on the same industrial unit by different analysts.

This paper presents an attempt to develop a criterion using which credible accident scenarios may be identified from among a large number of possibilities. The credible scenarios thus identified may then be processed for detailed consequence analysis. This would help in reducing the cost of the analysis and prevent undue emphasis on less credible scenarios at the expense of more credible ones.     

Fuzzy Application Procedure (FAP) for the risk assessment of occupational accidents

This paper concerns a procedure to quantify the risk of occupational accidents based on Fuzzy Logic approach, named Fuzzy Application Procedure (FAP). FAP was developed as a support tool, after the method based on fuzzy logic was developed and validated. The methodology and FAP support tool were found to be able to quantitatively assess the risk of occupational accidents for different industrial and site activities and to identify the most efficient intervention measures that can be taken to reduce risks. The application of FAP to two Italian industrial plant allowed the validation of the procedure. It can be seen how FAP should be considered easy to use for any type of company, with the only requirement of having a sufficient and homogeneous number of accidents recorded, so as to be able to correctly tune the reference parameters of the fuzzy methodology.     

Decision analysis on fire safety design based on evaluating building fire risk to life

This study presents a framework of decision analysis on fire safety design alternatives based on evaluating building fire risk to life. A probabilistic risk assessment method for occupant life is presented with consideration of some uncertainties of evacuation process and fire development at first. For occupant evacuation time assessment, occupant pre-movement time is characterized by normal distribution. For onset time to untenable conditions assessment, its uncertainty is considered as probability distribution according to the range of design fires. Based on event tree technique, probable fire scenarios are analyzed with consideration of the effect of fire protection systems, employees extinguishing, etc. It is difficult to make a precise assessment on probability and consequence of every fire scenario, but their lower bound and upper bound can be achieved based on statistical data. Therefore, Supersoft Decision Theory [Malmnäs, P.E., 1995. Methods of Evaluation in Supersoft Decision Theory. Department of Philosophy, Stockholm University, 365 Stockholm; Johansson, H., Malmnäs, P.E., 2000. Application of supersoft decision theory in fire risk assessment. Journal of Fire Protection Engineering 14, 55–84] that allows decision maker to utilize vague statement is utilized to integrate with risk assessment to make decision on different fire safety design alternatives. To express how to make decision on different fire safety design alternatives based on evaluating building fire risk to life, two hypothetical fire safety design alternatives for a commercial building are presented.     

模糊综合评价法在油气管道跨越工程风险评价中的应用

油气管道跨越工程项目开工数量不断增加,随之而来的安全、环保事故也大量发生。油气管道跨越工程进行风险评价对项目的安全、环保实施具有重要意义。利用节点分析方法对油气管道跨越工程进行风险识别,针对风险识别结果利用模糊综合评价法进行评价,得到油气管道跨越工程各施工单元的安全级数,评价结论为工程的安全、环保管理提供科学的依据。评价方法具有一定的应用和推广价值。     

AHP在概率风险评价中的应用

专家估计是 PRA的一个重要数据来源 ,为得到可信的估计值 ,分析人员要选择多个专家并对其估计进行综合。对影响专家估计的因素建立了层次模型 ,用 AHP对几个专家的估计进行了分析 ,给出其合理的权值 ,并进行了简单的灵敏度分析     

HFL模型在海上压裂工艺过程风险评估中的应用

为有效降低海上压裂工艺过程事故发生的可能性,建立将危险与可操作性研究(HAZOP)、事故树分析(FTA)和保护层分析(LOPA)集成的量化风险评估模型(HFL模型)。阐述HFL模型的集成机理和分析流程。以海上压裂工艺过程高压管线危险性分析为实例,开展该模型的研究与应用。在运用HAZOP方法对危险源初步辨识基础上,构建高压管线超压的蝴蝶结模型(BTM),确定导致事故发生的9种风险因素和5种事故后果,并估算高压管线断裂事故场景的初始事件概率和剩余事故风险。结果表明,现有的独立保护层(IPL)即超压电子保护装置无法使事故风险达到可接受水平,需要通过增加新的IPL,即安装井口保护装置和泄压装置,提高压裂过程高压管线运行的可靠性,确保剩余事故风险处于可接受水平。     

风险因子模糊评价法在钻机安全评价中的应用

钻机是石油与天然气钻井作业的重要设备,在使用过程中存在着极大风险,如果对其中的风险因素管理不善,风险转化为事故,将造成极大的损失,严重影响企业的形象与生产。为了预防石油与天然气钻井作业过程的事故发生,提高钻井队安全管理水平,论文采用通过对系统技术风险概率Pf和事故后果的严重程度Cf的估计和模糊评判的方法得到系统的风险状况Rf,为采取科学合理的风险消减措施提供了决策依据。论文以某型号电动钻机的电气控制系统为例进行风险分析,分析结果表明与实际情况比较符合。     

Developing a new alternative risk assessment framework in the work sites by including a stochastic and a deterministic process: A case study for the Greek Public Electric Power Provider

An individual method cannot achieve the optimum risk-assessment result in the worksites, and future perspectives should focus on the parallel application of a deterministic approach with a stochastic approach. In particular, the risk analysis and assessment techniques of the deterministic (DET) approach are classified into three main categories: (a) the qualitative, (b) the quantitative, and (c) the hybrid techniques (qualitative-quantitative, semi-quantitative). Furthermore, the stochastic (STO) approach includes the classic statistical approach (CSA) and the accident forecasting modeling (AFM). The objective of this paper is triple: (a) the presentation and classification of the main risk analysis and risk assessment methods and techniques of the deterministic approach and the stochastic approach as well, (b) the development and presentation of a new alternative risk assessment framework (called as STODET) including a stochastic and a deterministic process, and (c) the application of STODET in the Greek Public Power Corporation (PPC) by using occupational accidents that have been recorded, during the 17-year period of 1993-2009. In particular, the STODET application proves that required actions (or suppressive measures) are essential and must be taken in a medium-term period (1 working year) for abolishing the hazard sources.     

On the development of a new hybrid risk assessment process using occupational accidents’ data: Application on the Greek Public Electric Power Provider

The occupational accidents have a major impact upon human integrity and also bring about high costs for the social health and insurance system of a country. In addition, risk analysis is an essential process for the safety policy of a company, having as main aim the effacement of any potential of damage in a productive procedure, while the quantified risk evaluation is the most crucial part of the whole procedure of assessing hazards in the work. The main goal of this study is double: a) the development and presentation of a new hybrid risk assessment process (HRAP) and b) the application of HRAP in the Greek Public Power Corporation (PPC) (the unique electric power provider and the largest industry in Greece), by using occupational accidents that have been recorded, during the 12-year period of 1993-2004. The new process consists of four distinct phases a) the hazard sources’ identification phase, b) the risk consideration phase, c) the risk-evaluation phase, and d) the phase of the risk assessment and safety-related decision making. The results show that in some cases the risk value has been calculated in PPC to be higher than 500 (in the risk rating of 0-1000), which imposes the taking of suppressive measures for abolishing the danger source, while the fatal accident frequency rate (per 10⁸ man-hrs) is FAFR ≅ 2.4.     

基于模糊保护层的池火灾事故风险分析

为计算引发池火灾事故的风险值,提高事故风险的量化水平,判断现有风险控制措施是否满足风险容忍度的要求,为制定减缓风险措施提供依据,给出了新的池火灾风险评估模型。基于传统的保护层分析模型(LOPA),结合模糊集合理论,引入模糊风险矩阵进行风险评估,构建适用于引发池火灾事故的模糊保护层(fL OPA)风险分析模型。该模型的特点是将模糊逻辑和保护层分析结合,减少了传统保护层分析方法计算过程中的不确定性因素,引入严重度减少指数(SRI)概念,使严重度计算、风险评估更加准确。运用该模型对原油储罐泄漏池火灾事故风险进行分析,给出风险决策方案,判断现有保护措施是否能控制风险在可容忍范围内,实例验证了模型的可行性。     

A new approach to quantitative assessment of reliability of passive systems

The objective of this paper is to show how probabilistic reliability can be assessed for complex systems in the absence of statistical data on their operating experience, based on performance evaluation of the dominant underlying physical processes. The approach is to distinguish between functional and performance probabilities when dealing with the quantification of the overall probability of a system to perform a given function in a given period of time (reliability). In the case of systems where sufficient statistical operating experience data are available, one can focus the quantitative evaluation entirely on the assessment of the functional probability for a given active item (e.g. a pump) by assuming that the specification, layout, construction and installation is such that the item is providing the assigned performance, e.g. in the form of generating the required flow rate. This is how traditional probabilistic safety assessments (PSAs) focus the reliability analysis for the various safety features on the calculation of values for the availability per demand. In contrast, for various systems relevant in advanced technical applications, such as passive safety features in innovative reactor designs, it is essential to evaluate both functional and performance probabilities explicitly and combine the two probabilities later on. This is of course due to the strong reliance of passive safety systems on inherent physical principles. In practice, this means that, for example, in case of a passive cooling system based on natural circulation of a given medium, one has to evaluate and to assess the probability to have a medium condition and a flow rate such that a cladding temperature, represented by a probability distribution, can be hold at a required level. A practical example of this method is given for the case of the reliability assessment of a residual passive heat removal system. General conclusions are drawn regarding reliability estimation of complex, interconnected systems in the absence of statistical performance data, such as for infrastructures.     

定量风险评价在炼化一体化项目中的应用

本文阐述了定量风险评价的指标、模型和一般程序,给出了定量风险评价的标准,采用定量风险评价的方法对某企业规划建设的炼化一体化项目进行个人风险和社会风险水平计算。个人风险计算结果表明,该炼化一体化项目所在厂区内没有出现1×10-3的风险等值线,1×10-4、1×10-5和1×10-6的风险等值线也没有超出厂区边界,说明该炼化一体化项目厂区内部和周边人员所面临的个人风险是可以接受的。社会风险计算结果表明,该炼化一体化项目的社会风险曲线处在可容许区范围内,没有进入不可容许区和ALARP区,说明该项目的社会风险也是可以接受的。本文采用的定量风险评价方法可为规划或已建炼化一体化项目进行风险水平评估提供必要的参考依据。     

Potential barriers to the competence assessment of Offshore Installation Managers: A hermeneutic perspective.

The Offshore Installation Manager (OIM) performs one of the most critical roles within the UK offshore Oil and Gas Industry. The OIM is responsible for the safety and well-being of all persons on-board and within 500 m of the installation whilst operating within a complex environment where multiple organisations and stakeholders interact. The persistence of major incidents in the industry highlights the importance of OIM competence in controlling emergencies, consequently the research aims to identify the potential barriers that can limit or prevent the proficient competence assessment of an OIM in this situation. The OIM role is investigated by qualitative analysis of key documents using hermeneutics to interpret text and to identify the potential barriers to effective competence assessment. Such analysis has historically been used within the domains of theology, business and law. Hermeneutics takes into account the cultural, historical and social environment at the time of issue of the document, and semiotics, i.e. the study of signs and symbols, their use and interpretation.Analysis is ongoing, however the six potential barriers to the effective competence assessment of OIMs in controlling emergencies identified to date are discussed. These barriers are associated with the multiple definitions of competence that exist in the UK and worldwide; the current predominance of competence assessment by observation; the lack of definitive competence requirements for trainers and assessors; the complexity in UK legislation and the interaction between UK Government departments and concerns associated with goal setting legislation when applied to competence assessment.The output from the research will assist industry Duty Holders improve the competence assessment of their appointed OIMs and allow safety engineers to consider the probable competence of an OIM in a given environment at a given point in time.     

灰色系统理论在高校学生公寓火灾风险评价中的应用

针对高校学生公寓火灾的安全问题,参考相关标准、征求专家意见,建立了高校学生公寓火灾风险评价指标体系,并确定了权重。在此基础上,根据灰色系统理论原理对高校学生公寓火灾风险评价进行研究,建立评价模型,运用改进后的多层次灰色关联度分析法对青岛市某高校10#学生公寓的火灾风险进行评价,得出火灾风险等级为二级,即安全。研究结果表明,所建立的评价模型对学生公寓火灾的风险评价具有良好的应用价值,也为火灾风险评价提供了一种新的综合评价方法。     

Application of domino effect quantitative risk assessment to an extended industrial area

Escalation of primary accidental scenarios triggering a “domino effect” have caused extremely severe accidental events in the chemical and process industry. The identification of possible escalation events is required in the safety assessment of sites where relevant quantities of hazardous substances are stored or handled. In the European Union, “Seveso-II” Directive requires the assessment of on-site and off-site possible escalation scenarios in sites falling under the obligations of the Directive. In the present study, a methodology developed for the quantitative assessment of risk due to domino effect was applied to the analysis of an extended industrial area. Recently developed equipment damage probability models were applied for the identification of the final scenarios and for escalation probability assessment. The domino package of the Aripar-GIS software was used for risk recomposition. The results evidence that quantitative risk assessment of escalation hazard is of fundamental importance in order to identify critical equipment and to address prevention and protection actions.     

兰州地区人群对六六六的暴露及健康风险评价

为研究兰州地区六六六(HCH)对人群的健康风险,应用改进的美国环境保护署(US EPA)多介质暴露模型,结合兰州地区人群状况,计算了各年龄人群通过11种暴露途径对六六六的暴露量.结果表明,兰州地区居民对环境中六六六的终身日平均暴露量为2.01×10-5 mg/(k·d)(儿童)和2.53×10-5 mg/(kg·d)(成人).暴露途径中以食物暴露为主导,其次是呼吸暴露,皮肤暴露作用很小.食物中贡献较大的为谷物和蔬菜.相应的健康风险度分别为5.40×10-9 a-1(男性)和6.30× 10-9a-1(女性).兰州地区六六六居民人体健康风险度低于可接受健康风险度标准,兰州地区六六六人群暴露水平与天津、太原、太湖地区相比存在一定的差异,女性对六六六的暴露量高于男性.兰州人群成人的六六六暴露量大于儿童,成人是六六六暴露风险最高的群体.各项参数中,谷物和蔬菜摄食量和相应的六六六残留浓度是影响暴露的重要因素.通过蒙特卡罗模拟得到各年龄段人群对HCH的日均暴露量的分布特征,各输出变量均服从对数正态分布.     

五元联系数在地表水环境质量评价中的应用

五元联系数μ=a bi cj dk el是集对分析理论中同异反联系数μ=a bi cj的一种拓广.在前人工作基础上,进一步研究了五元联系数中a、b、c、d、e的大小关系,总结提出了五元联系数同异反态势新表,并将其应用于地表水环境质量评价.其中的a、b、c、d、e分别对应于Ⅰ、Ⅱ、Ⅲ、Ⅳ、V类地表水环境质量状况.实例研究表明,集对分析中的五元联系数用于地表水环境质量评价是可行的.在给出优劣排序的同时,还给出优劣的水平.