浅议风险观对风险评价方法论的影响

风险观对安全科学的发展具有重要的指导意义。本文从风险本体论、风险认识论和风险方法论三个方面论述了风险观的发展变迁。简述了风险本体论从一维、二维到三维或多维的发展历程,总结了风险认识论从技术导向到社会文化导向的变化,给出了风险方法论的分类。总结了风险方法论的重要组成部分即风险评价的发展过程,探讨了确定性风险评价、概率性风险评价和定量风险评价等评价方法在风险本体论和认识论发展背景下的继承性等问题,探讨风险本体论和认识论对风险评价方法论的影响,提出风险沟通研究的必要性。     

Safety is the antonym of risk for some perspectives of risk

Safety and safe are terms closely related to risk, but do they extend beyond the realm of risk? Is safety/safe just the antonym of risk, or the same as acceptable risk? This issue has been given due attention in the literature and in this paper we explore how different perspectives of risk affect the relationship between safety/safe and risk. If risk is defined as an expected value or as a measure of the probability and severity of adverse effects, the conclusions would be different than if the essential component of risk is uncertainty. For risk understood as uncertainty about and severity of the consequences of an activity we argue that safe means acceptable risk. Three dimensions of safety are discussed; events and consequences (harm), probability and uncertainty.     

The development of probabilistic models to estimate accident risk (due to runway overrun and landing undershoot) applicable to the design and construction of runway safety areas

The risks of landing overrun (LDOR – LanDing OverRun), Take-off Overrun (TOOR – Take-Off OverRun) and landing undershoot (LDUS – LanDing UnderShoot) are dependent on multiple factors related to operating conditions. These include wind, runway surface conditions, landing or take-off distances required, the presence of obstacles, runway distance available, the existence and dimensions of runway safety areas.In this paper we propose risk models for runway overrun and landing undershoot, using a probabilistic approach. These models are supported by historical data on accidents in the area around the runway and will enable us to determine if the risk level is acceptable or whether action must be taken to mitigate such risks at a given airport. Furthermore, these models permit comparison of the results of different risk mitigation actions in terms of operational risk and safety.The principal advantage of this method is the high quality results obtained for a limited investment in terms of time, computing power and data. As such the method is extremely practical and easy to apply in aerodrome planning, development and operation.     

Inherent risk assessment—A new concept to evaluate risk in preliminary design stage

Quantitative Risk Assessment (QRA) has been a very popular and useful methodology which is widely accepted by the industry over the past few decades. QRA is typically carried out at a stage where complete plant has been designed and sited. At that time, the opportunity to include inherent safety design features is limited and may incur higher cost. This paper proposes a new concept to evaluate risk inherent to a process owing to the chemical it uses and the process conditions. The risk assessment tool is integrated with process design simulator (HYSYS) to provide necessary process data as early as the initial design stages, where modifications based on inherent safety principles can still be incorporated to enhance the process safety of the plant. The risk assessment tool consists of two components which calculate the probability and the consequences relating to possible risk due to major accidents. A case study on the potential explosion due to the release of flammable material demonstrates that the tool is capable to identify potential high risk of process streams. Further improvement of the process design is possible by applying inherent safety principles to make the process under consideration inherently safer. Since this tool is fully integrated with HYSYS, re-evaluation of the inherent risk takes very little time and effort. The new tool addresses the lack of systematic methodology and technology, which is one of the barriers to designing inherently safer plants.     

Incorporating organizational factors into probabilistic risk assessment of complex socio-technical systems: Principles and theoretical foundations

The current generation of Probabilistic Risk Analysis (PRA), particularly those for technical systems, does not include an explicit representation of the possible impacts of organization and management on the safety performance of equipment and personnel. There are a number of technical challenges in developing a predictive model of organizational safety performance. There is a need for a widely accepted and theoretically sound set of principles on which models of organizational influences could be developed and validated. As a result of a multidisciplinary effort, this paper explores the feasibility of developing such principles and proposes a set of principles for organizational safety risk analysis. Then, as a realization of the proposed modeling principles, a safety risk framework, named Socio-Technical Risk Analysis (SoTeRiA), is developed. SoTeRiA formally integrates the technical system risk models with the social (safety culture and safety climate) and structural (safety practices) aspects of safety prediction models, and provides a theoretical basis for the integration. A systematic view of safety culture and safety climate leaves an important gap in modeling complex system safety risk, and SoTeRiA, describing the relationship between these two concepts, bridges this gap. The framework explicitly recognizes the relationship among constructs at multiple levels of analysis, and extends the PRA framework to include the effects of organizational factors in a more comprehensive and defensible way.     

A retro-synthesis approach for hazard evaluation and risk screening

Risk screening instruments can be very useful for evaluating hazards and establishing priorities for risk reduction. Further, these instruments can provide educational value to field staff when they are distributed to individuals outside of traditional process safety roles. This paper describes a retro-synthesis technique whereby risk screening instruments can be readily generated for these types of hazard evaluation and priority setting activities. Further, by utilizing a retro-synthesis approach, data gathered at the field level can often be drawn upon at a later point if a more detailed risk assessment is required. The retro-synthesis approach involves working backwards from traditional risk functions (relationships) so as to define the predominant elements for incorporation within the risk screening instrument. Compared to conventional techniques, the retro-synthesis approach utilizes deductive reasoning techniques in a manner similar to Fault Tree Analysis (FTA). However, the directional relationships that are established between causes and consequences become inverted.For example, risk can be defined as a function of “likelihood” and “severity”, where “severity” may be a function of the “energy released” and the “exposure group”. Similarly, the “energy released” is often a function of the “properties of the material involved” and the “amount of material released”. Through identifying these relationships, “risk” in this example can be characterized as a function of “likelihood”, “exposure group”, “properties of the material involved”, and “amount of material released”. Further, by highlighting the various influential parameters, the relationships between each of these parameters, as related to risk, can also be understood. Once the various terms and functions are defined, screening categories can then be developed to quantify each of the terms so as to allow for an approximation of the relative risk involved for the given scenarios.This approach benefits from being simple to develop, maintaining alignment with the mathematics required for more detailed quantitative risk assessments, and generating screening categories which can be given to field staff. Through careful construction of the screening categories field staff can then rapidly, and in a reproducible manner, screen a large number of scenarios so as to identify those situations which represent priority hazards.     

A risk perspective suitable for resilience engineering

In recent years, resilience engineering has been given considerable attention among safety researchers and analysts. The area represents a new way of thinking about safety. Whereas conventional risk management approaches are based on hindsight knowledge, failure reporting and risk assessments calculating historical data-based probabilities, resilience engineering looks for ways to enhance the ability of organisations to be resilient in the sense that they recognise, adapt to and absorb variations, changes, disturbances, disruptions and surprises. The implications of this shift in thinking are many. We focus in this paper on the understanding of the risk concept and how risk can be assessed and treated. The traditional ways of looking at risk are not suitable for use in resilience engineering, but other risk perspectives exist. A main purpose of this paper is to draw attention to such perspectives, in particular one category of perspectives where probability is replaced by uncertainty in the definition of risk. We argue that the basic ideas of resilience engineering can be supported by such risk perspectives.     

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.     

A quantitative risk management framework for dust and hybrid mixture explosions

Dust and hybrid-mixture explosions continue to occur in industrial processes that handle fine powders and flammable gases. Considerable research is therefore conducted throughout the world with the objective of both preventing the occurrence and mitigating the consequences of such events. In the current work, research has been undertaken to help move the field of dust explosion prevention and mitigation from its current emphasis on hazards (with an accompanying reliance on primarily engineered safety features) to a focus on risk (with an accompanying reliance on hierarchical, risk-based, decision-making tools). Employing the principles of quantitative risk assessment (QRA) of dust and hybrid-mixture explosions, a methodological framework for the management of these risks has been developed.The QRA framework is based on hazard identification via credible accident scenarios for dust explosions, followed by probabilistic fault-tree analysis (using Relex – Reliability Excellence – software) and consequence severity analysis (using DESC – Dust Explosion Simulation Code – software). Identification of risk reduction measures in the framework is accomplished in a hierarchical manner by considering inherent safety measures, passive and active engineered devices, and procedural measures (in that order). An industrial case study is presented to show how inherent safety measures such as dust minimization and dust/process moderation can be helpful in reducing dust and hybrid-mixture explosion consequences in a 400-m³ polyethylene storage silo.     

A comparison of required coefficient of friction for both feet in level walking

The required coefficient of friction (RCOF) is one of the critical elements in determining whether a slip incident might occur. Most researchers, when measuring RCOF, do not differentiate between the two feet of the same participant under the same walking condition. Results from a recent study (Chang et al., 2010) indicated that the stochastic distributions of the RCOF of both feet were different in 76% of the cases. Using the previous data (Chang et al., 2010), this paper presents a comparison of the RCOF for both feet of 50 participants under four level walking conditions resulting from two footwear types and two walking speeds using a t-test, commonly used by safety professionals to compare two pools of data. The current results indicated that 78% of the RCOF data showed a statistically significant difference between the RCOF from two feet for the same participant under each walking condition. The results of the logistic regression analysis used to identify factors that contributed to the outcome of the t-test indicated that the walking speed was the only factor with a statistical significance (p = 0.044).     

A systemic methodology for risk management in healthcare sector

The recent biomedical, technological, and normative changes have led healthcare organizations to the implementation of clinical governance as a way to ensure the best quality of care in an increasingly complex environment. Risk management is one of the most relevant aspects of clinical governance and approaches put forward in literature highlight the necessity to perform comprehensive analyses intended to uncover root causes of adverse events.Contributing to this field, the present paper applies Reason’s theory of failures to work out a systemic methodology to study risks impacting not only directly but also indirectly on patients. Also, the steps of such approach are organized around Human Reliability Assessment phases, in order to take into account the human component of healthcare systems. This framework is able to foster effective decision making about reducing failures and waste and to improve healthcare organizations’ maturity towards risk management.The developed methodology is applied to the pharmacy department of a large Italian hospital. An extensive validation in different healthcare settings is required to fully prove benefits and limitations.     

A methodology for assessing underground coal mines for high safety-related risk

In 2008 the authors developed a methodology for assessing underground coal mines for high risk for major-hazard events. It focused on major hazard-related violations of safety standards associated with high-risk conditions. Later using the same stratified pilot sample of 31 mines, injury measures and MSHA citation data were combined into a Safe Performance Index (SPI). Using 2009 data, the database was expanded to 107 mines, which is a 30% sampling of all underground coal mines. The SPI was used to assess the relative safety-related risk of mines, including by mine-size category. The methodology can be used to assist companies, the Mine Safety and Health Administration, or state agencies in targeting mines with high risk for serious injuries and elevated citations for remediation of their violation and/or injury experience.     

A fuzzy multi-attribute model for risk evaluation in workplaces

Risk assessment constitutes a critical phase of the safety management process. It basically consists of evaluating the risks involved in the execution of working activities, so as to provide the managers with information suitable to address intervention measures. The most important activity in risk assessment is the risk evaluation task but, despite its importance, national and international regulations have never formalized a standard methodology for addressing it, leaving companies complete freedom to adopt the approach they consider appropriate. As a consequence, companies generally settle on the use of simple methodologies which frequently are not able to emphasize all the main aspects affecting risk in the workplace and to produce a precise ranking of hazardous activities. In this paper, a new methodology for risk evaluation is then proposed with the aim to overcome limitations of the classical approaches. In particular, new factors are introduced to take into account effects of human behavior and environment on risk level, other than the classical injury magnitude and occurrence probability of an accident. The proposed methodology also integrates an estimative approach based on the fuzzy logic theory, which permits more coherence in the evaluation process, producing a very suitable final rank of hazardous activities. Finally, an actual case study is reported to show the capabilities of the new risk evaluation model.     

A new method for risk assessment of pillar recovery operation

Safe pillar recovery operations can result in better miner safety and more efficient recovery of ore reserves. Several parameters influence on safety of pillar recovery operation. Each of these parameters is able to reduce safety of operation and cause to detrimental effects during pillar recovery. In this paper, by emphasizing ground control aspects, the most important technical parameters influencing on safety of pillar recovery are introduced and the role of them is described. Then, a new method is presented by combining all of these parameters to assess overall risk of pillar recovery operation in pre-developed room and pillar mines. The proposed method involves calculating the PR-Risk (Pillar Recovery-Risk) indicator. PR-Risk value is between 0 and 100 that based on overall risk of pillar recovery operation divides into four categories: low, medium, high, and very high. PR-Risk is an important indicator for predicting the safety of pillar recovery operation and based on it decision can be made about the safe implementation of operation. Finally, the overall risk of pillar recovery operation in main panel of Tabas Central Mine, located in the mid eastern of Iran, is assessed by use of proposed method in this paper. PR-Risk value in this panel was obtained 51 that show overall risk of operation is medium. Moreover, based on individual assessment of parameters, for the safe implementation of operation and reduction of related risks, reinforcement of roof prior to beginning of operation and partial pillar extraction have been suggested as the most efficient controlling measures.     

突发公共事件应急信息系统平战结合

结合我国应急体系建设的要求,论述了突发公共事件应急信息系统的结构、组成和功能;分析了应急信息系统在平常时期(预防和应急准备阶段)和战时(应急响应阶段和恢复阶段)在整个应急管理过程中不同的功能.指出了我国应急信息系统平战结合重要意义和当前存在的关键问题;提出了今后在应急体系建设和如何实现平战结合方面的建议.     

A Bayesian approach to construct bow tie diagrams for risk evaluation

Bow tie diagrams have become a popular method for risk analysis and safety management. This tool describes the whole scenario of a given risk graphically, and proposes preventive and protective barriers to reduce, respectively, its occurrence and its severity. The weakness of bow tie diagrams is that they are restricted to a graphical representation of different scenarios exclusively designed by experts that ignore the dynamic aspect of real systems. Thus, constructing bow tie diagrams in an automatic and dynamic way remains a real challenge. This paper proposes a new Bayesian approach to construct bow tie diagrams from real data and improve them by adding a new numerical that enables us to implement the appropriate preventive and protective barriers in a dynamic manner.     

货运网络风险决策的变分不等式模型及算法

以往的货运网络均衡研究注重参与者之间的利润均衡,缺少对运输安全风险因子规律的分析.针对这一问题,考虑运输安全风险成本,对托运人、承运人和运输管理者3个参与者的运营收益进行分析,提出了道路货运网络均衡的变分不等式模型,通过变步长投影算法完成优化模型的求解和验证.最后,通过使用模拟数据集揭示道路货运安全风险发生的主要规律.结果表明,该方法能有效找到运输网络利润与安全风险的均衡点.     

A fuzzy risk assessment approach for occupational hazards in the construction industry

The techniques in the construction industry have been improved due to the rapid development of science and technology. However, the constructional hazards are not decreased as expected. To reduce or prevent occupational hazards in the construction industry, a fuzzy risk assessment method was proposed to provide a prevention and improvement technique against occupational hazards. This method used two-stage quality function deployment (QFD) tables to represent the relationships among construction items, hazard types and hazard causes. A fuzzy analytic network process (ANP) method was developed to identify important hazard types and hazard causes. Failure modes and effect analysis (FMEA) was performed to assess the risk value of hazard causes based on the fuzzy inference approach. The proposed method was applied to a telecom engineering company in southern Taiwan. The performance evaluation result indicated that this method can provide satisfactory risk assessment values of hazard causes and relevant improvement strategies.     

直升机医疗救援的安全风险评价模型研究

为对直升机医疗救援任务实施有效的风险管理,提升其飞行安全水平,运用SHELL模型对直升机医疗救援飞行进行风险识别,确定了直升机医疗救援的风险因素.运用Borda序值法和风险矩阵法建立了 Borda-风险矩阵评价模型.运用Borda-风险矩阵评价模型对G通航进行实证分析,结果表明该评价模型具有可行性,可为直升机医疗救援风险评价提供参考.     

基于环境后果评价的环境风险源分级模型研究

为解决目前环境风险源分级存在的指标单一和不确定性较大的问题,综合考虑危险物质特性、环境迁移规律及环境危害特性,建立较全面的环境后果评价指标体系和评价模型,并应用蒙特卡罗方法分析评价过程中的不确定性,构建以环境后果综合评价为基础的环境风险源分级模型.根据2009年4月对上海市闵行区重点工业企业危险源的调研结果,将模型用于上海某油墨有限公司甲苯储罐的风险源分级评价.结果表明,该风险源的综合评价指数为0.007 9～0.259 4,根据90%的累积概率对应的评价指数值(0.104 0)确定该风险源为重大环境风险源.本文建立的模型可有效评价环境影响后果,为环境风险源的分级管理提供了科学依据.