Technical modeling in integrated risk assessment of chemical installations

This paper presents the technical model of an Integrated Quantitative Risk Assessment method, taking into account management as well as technical design and producing risk level measures. The basic steps of the technical model consist in developing a Master Logic Diagram (MLD) delineating the major immediate causes of Loss of Containment and associated quantitative models for assessing their frequency. Appropriate management models quantify the parameters of the technical model on the basis of the safety management system of the installation. The methodology is exemplified through its application on the risk assessment of a LPG scrubbing tower of an oil refinery. A detailed technical model simulating the response of the system to various initiating events is developed, along with a detailed model simulating the influence of the plant-specific management and organizational practices. The overall effect is quantified through the frequency of release of LPG as a result of a Loss of Containment in scrubbing towers of the refinery.     

Semi-quantitative risk assessment of commercial scale supply chain of hydrogen fuel and implications for industry and society

This paper is derived from a study on the safety of bulk transport and storage of hydrogen as a fuel, carried out by the Health and Safety Laboratory (HSL) for the Department for Transport (DfT). The aim of the study was to identify the knowledge and data required to develop fully a risk assessment for a hydrogen delivery and storage infrastructure. The methodology used was to begin to carry out a risk assessment for a representative delivery and storage supply chain, using a risk assessment methodology commensurate with the availability of necessary data. Semi-quantitative risk assessment was carried out through top-down HAZID brainstorming, consequence modelling using commercially available software, and use of a risk matrix.Finally through the risk assessment carried out and relevant literature review, the gaps in hazard identification, consequence modelling and frequency assessment, which should be filled to develop a quantified methodology, were compiled.Using data for current UK LPG consumption, comparisons were made between hydrogen and LPG for mode of failures and number of trips required to supply equivalent energy demand. The implications of using ammonia as a hydrogen carrier (hydrogen is within the ammonia molecule) and regulatory implications on hydrogen fuelling or storage sites are also discussed.     

An extension to Fuzzy Fault Tree Analysis (FFTA) application in petrochemical process industry

Fault Tree Analysis (FTA) is an established technique in risk management associated with identified hazards specific to focused fields. It is a comprehensive, structured and logical analysis method aimed at identifying and assessing hazards of complex systems. To conduct a quantitative FTA, it is essential to have sufficient data. By considering the fact that sufficient data is not always available, the FTA method can be adopted into the problems under fuzzy environment, so called as Fuzzy Fault Tree Analysis (FFTA). This research extends FFTA methodology to petrochemical process industry in which fire, explosion and toxic gas releases are recognized as potential hazards. Specifically, the case study focuses on Deethanizer failure in petrochemical plant operations to demonstrate the proposed methodology. Consequently, the study has provided theoretical and practical values to challenge with operational data shortage in risk assessment.     

Assessment of the effect of technical and management characteristics on the frequency of release from piping: An application to a gas storage facility

The assessment of the frequencies of release from piping due to losses of containment is an essential step in the preparing Safety Reports, drawn up as required by the so-called “Seveso” Directive. These are usually calculated starting from the frequencies of random rupture included in international databases and are not plant-specific, furthermore, the quantification of the effect of the safety management system of the facility is not easy. A simple and flexible approach quantifying technical and management characteristics of the plant has been proposed by Milazzo and co-workers in 2010; it is based on the modification of the frequency taken from literature, through the use of the percentages of failure causes actually possible in that plant, and the judgment about their management. The data about the failure causes are taken from the literature and modified by using corrective factors to adapt them to the industrial context. To make possible the application of the method to a large number of major-hazard industry types, some aspects of the approach needed to be improved; these have been identified during a development project coordinated by RINA Consulting, on behalf of Saipem, with the collaboration of the University of Messina. The improvement of the approach focused on two main points, the development of a method to calculate the corrective factors for the failure causes associated with corrosion and erosion phenomena and the strengthening of the methodology for the formulation of the judgment about the safety management. This paper illustrates the fully improved method, as well as an application to a typical gas storage plant.     

The development of a more risk-sensitive and flexible airport safety area strategy: Part I. The development of an improved accident frequency model

This two-part paper presents the development of an improved airport risk assessment methodology aimed at assessing risks related to aircraft accidents at and in the vicinity of airports and managing airport safety areas (ASAs) as a risk mitigation measure. The improved methodology is more quantitative, risk-sensitive, flexible and transparent than standard risk assessment approaches. As such, it contributes to the implementation of Safety Management Systems at airports, as stipulated by the International Civil Aviation Organisation.The first part of the paper presents the methodological advances made in the development of accident frequency models; namely the building of a single comprehensive database of all relevant accident types, the collection and use of normal operations data in quantifying the criticality of a series of risk factors, and modelling accident frequency using multivariate logistic regression. The resulting models have better goodness-of-fit, sensitivity and specificity than standard risk assessment methodologies.     

综合安全评价(FSA)方法

为提高国际海运安全管理的决策水平,国际海事组织(IMO)接受并倡导由英国海运界提出的综合安全评价(FSA)方法,笔者对FSA方法作了本质性分析和应用性研究。阐述了FSA的由来,5个组成步骤及相互关系和流程,揭示了FSA与风险管理和安全系统工程的渊源;介绍了危险识别的7种工具;对步骤二“风险评估”重点引入了半定量分析方法和定量分析方法,并用集合论观点讨论了事故频率和后果严重度的计算方法;介绍了风险控制方案的“成本与效益评估”的数学模型;归纳了FSA方法的优缺点。指出FSA是一种集风险评价和成本/效益评估于一体,兼顾技术性与经济性,可广泛兼容具体评价方法和普遍适用各类风险评价的框架性方法,但具体应用需要有效整合适用的定性和定量方法。     

基于安全系统工程的铁路站段安全管理信息系统研究

随着安全逐级负责制等各项安全管理机制的建立和运行以及ISO90 0 0系列标准在铁路站段的推广和普及 ,要求铁路站段急需改变传统的、经验的管理模式 ,建立基于安全系统工程的、综合运用现代技术手段的安全科学管理体系。笔者在综合考虑人、机、环境三要素的基础上 ,结合安全系统工程方法 ,对铁路站段安全管理信息系统的基本功能、系统设计等进行了深入分析 ,实现了安全信息的自动处理、对事故或隐患的安全分析、安全预测和安全评价功能 ,为安全管理科学化提供有力的技术支持。以大同西电力机务段为例 ,对安全管理信息系统进行了实用和考核 ,取得了预期效果     

A methodology to model causal relationships on offshore safety assessment focusing on human and organizational factors

INTRODUCTION: Focusing on people and organizations, this paper aims to contribute to offshore safety assessment by proposing a methodology to model causal relationships. METHOD: The methodology is proposed in a general sense that it will be capable of accommodating modeling of multiple risk factors considered in offshore operations and will have the ability to deal with different types of data that may come from different resources. Reason's "Swiss cheese" model is used to form a generic offshore safety assessment framework, and Bayesian Network (BN) is tailored to fit into the framework to construct a causal relationship model. The proposed framework uses a five-level-structure model to address latent failures within the causal sequence of events. The five levels include Root causes level, Trigger events level, Incidents level, Accidents level, and Consequences level. To analyze and model a specified offshore installation safety, a BN model was established following the guideline of the proposed five-level framework. A range of events was specified, and the related prior and conditional probabilities regarding the BN model were assigned based on the inherent characteristics of each event. RESULTS: This paper shows that Reason's "Swiss cheese" model and BN can be jointly used in offshore safety assessment. On the one hand, the five-level conceptual model is enhanced by BNs that are capable of providing graphical demonstration of inter-relationships as well as calculating numerical values of occurrence likelihood for each failure event. Bayesian inference mechanism also makes it possible to monitor how a safety situation changes when information flow travel forwards and backwards within the networks. On the other hand, BN modeling relies heavily on experts' personal experiences and is therefore highly domain specific. IMPACT ON INDUSTRY: "Swiss cheese" model is such a theoretic framework that it is based on solid behavioral theory and therefore can be used to provide industry with a roadmap for BN modeling and implications. A case study of the collision risk between a Floating Production, Storage and Offloading (FPSO) unit and authorized vessels caused by human and organizational factors (HOFs) during operations is used to illustrate an industrial application of the proposed methodology.     

生产作业区重大危险源评估方法研究

危险源是危险的根源,是系统中存在的可能发生意外释放能量的危险物质,开展重大危险源评估工作可有效预防和控制生产作业区重大安全事故的发生,保障人民群众生命财产安全,同时也为生产作业区安全监督管理提供依据。以某生产作业区为例,研究了生产作业区重大危险源辨识标准及分类分级方法,研究了重大危险源安全现状及危害等级的安全评估方法,指出了企业在重大危险源安全管理上应采取的安全技术措施和安全管理措施,为提高生产作业区安全管理水平,制定重大危险源专项应急预案提供了依据,上述辨识和评估思路和方法可为其他企业借鉴参考。     

Quantitative risk assessment model of hazardous chemicals leakage and application

The hazardous chemical accidents remain a matter of major concern. However, there is a dearth of practical measures about the emergency management of hazardous chemicals leakage. Therefore, in order to provide more accurate management plan, quantitative risk assessment has become a critical issue in chemical industry. The main aim of this study is to quantify the risk of hazardous chemicals leakage, and take precautions against the accidents. In this study, a Fire-Explosion-Poisoning Quantitative Probability Model (FEPQPM) has been established. The paper introduced the probability analysis methods to analyze derivative accidents caused by hazardous chemicals leakage, established quantitative risk assessment models, and made acceptable risk level analysis. This model has been applied to quantitatively assess an enterprise’s storage tank at Changshou Chemical Industrial Distripark (CID) in Chongqing, China. Evaluation results are in line with the actual situation of the CID. It is shown that the probability of poisoning is very large, causing more economic loss than the other two types of accidents, and death toll of leakage accident increases over time, resulting in greater economic losses. The risk level of leakage accident involving poisoning is unacceptable.     

The development of a more risk-sensitive and flexible airport safety area strategy: Part II. Accident location analysis and airport risk assessment case studies

This two-part paper presents the development of an improved airport risk assessment methodology aimed at assessing risks related to aircraft accidents at and in the vicinity of airports and managing Airport Safety Areas (ASAs) as a risk mitigation measure. The improved methodology is more quantitative, risk-sensitive, flexible and transparent than standard risk assessment approaches. As such, it contributes to the implementation of Safety Management Systems at airports, as stipulated by the International Civil Aviation Organisation.The second part of the paper presents the analysis of accident locations, including the plotting of Complementary Cumulative Probability Distributions for the relevant accident types. These were then used in conjunction with the improved accident frequency models to produce Complementary Cumulative Frequency Distributions that could be used to assess risks related to specific runways and determine Airport Safety Area (ASA) dimensions necessary to meet a quantitative target level of safety. The approach not only takes into account risk factors previously ignored by standard risk assessments but also considers the operational and traffic characteristics of the runway concerned. The use of the improved risk assessment technique and risk management strategy using ASAs was also demonstrated in two case studies based on New York LaGuardia Airport and Boca Raton Airport in Florida.     

车站、机场、码头火灾风险管理定量方法的研究

在对车站、机场、港口等旅客站点火灾风险因数识别的基础上，提出火灾风险定量管理模型，经验和研究证明，该模型十分有效，是火灾风险定量管理的一个有效可行的工具，对火灾风险管理的方法进行了阐述／。     

城市重大危险源区域风险评价方法研究

针对城市应急管理的特点,提出了一种城市重大危险源区域风险评价方法。在ARAMIS方法的基础上,对严重度计算进行了修订,引入了急性暴露指南（AEGL）标准对事故后果进行分区;同时,增加了与应急救援效率相关的指标进行风险目标的脆弱性评估;利用GIS技术,对严重度和脆弱性进行叠加分析,绘制出城市重大危险源区域风险地图。以液氨储罐毒气泄漏事故为例,对文中提出的方法进行了验证。实例分析表明,此方法为快速获取城市重大危险源区域风险的空间分布格局提供了新思路,对于降低城市突发环境污染事故的影响和辅助决策者制定科学的城市公共安全管理决策具有一定的现实意义。     

Quantitative risk assessment of the Italian gas distribution network

European Critical Infrastructures include physical resources, services, information technology facilities, networks and infrastructure assets, which, if disrupted or destroyed would have a serious impact on the health, safety, security, economic or social well-being of the Member States.The gas distribution network is a critical infrastructure and its failure can cause damage to structures and injury to people.The aim of this paper is to analyze and then assess the risk of the Italian high pressure natural gas distribution network.The paper describes an application of a methodology for quantitative risk assessment.Failure frequencies considered in risk calculation were found in the European Gas pipeline Incident data Group (EGIG) database, whereas consequences were computed as a function of pipe diameter and operating pressure for each section of the network. The results of this quantitative risk assessment is the determination of local and social risks for the Italian North East Area.     

Quantitative risk assessment of domino effect in Natech scenarios triggered by lightning

Lightning strike is the natural event more frequency causing Natech accidents involving atmospheric storage tanks. Despite the resulting fires have usually limited severity and only local effects, domino effect may cause the escalation of these primary events, possibly affecting nearby pressurized storages and process equipment, thus resulting in relevant increase in the potential area impacted. A methodology was developed for the quantitative assessment of risk due to domino effects caused by Natech accidents triggered by lightning. A comprehensive procedure was obtained, tailoring lightning risk assessment to include probabilistic models for domino escalation based on probit approach and combinatorial analysis. The methodology was applied to a case-study to evidence the shift in risk figures due to domino effect and the credibility of the secondary domino scenarios. The results of the case-study show that an increase up to two orders of magnitude with respect to risk calculated for conventional scenarios is possible when considering lightning-induced Natech primary scenarios and their escalation.     

Aspects of risk analysis associated with major failures of fuel pipelines

This paper presents a methodology of risk assessment for hazards associated with transportation of dangerous substances in long pipelines. The proposed methodology comprises a sequence of analyses and calculations used to determine basic reasons of pipeline failures and their probable consequences, taking individual and societal risk into account. A specific feature of this methodology is a combination of qualitative (historical data analysis, conformance test and scoring system of hazard assessment) and quantitative techniques of pipeline safety assessment. This enables a detailed analysis of risk associated with selected hazard sources by means of quantitative techniques. On the ground of this methodology typical problems that usually pose serious threat and constitute part of risk analysis for long fuel pipelines are also presented. To verify above methodology, complete risk analysis was performed for the long distance fuel pipeline in Poland.     

盐穴地下储气库事故统计及风险分析

借鉴输气管道和二氧化碳地下封存设施的风险评价方法,结合盐穴地下储气库的事故统计分析,对储气库系统中的潜在风险因素进行12大类、35小类的初步分类,并归纳总结了盐穴地下储气库的3种主要事故类型。采用事故树分析的风险评价方法,对13种主要风险因素进行风险识别。在此基础上,提出定量风险评价的重要工程模型,其包括气体水合物模型、盐穴稳定性评价模型以及气体泄漏模型。该风险分析方法和工程模型有助于定量评价盐穴地下储气库的主要风险因素,为储库的安全稳定运行提供了科学依据。     

Enhancing regional process safety management

As industrial operations expand, major incidents continue to affect people, damage facilities, and impact the environment. In the last 20 years, about 50% of these incidents occurred in facilities that had implemented some form of Process Safety Management (PSM) and 50% came about in smaller facilities that did not include such planning (Demichela et al., 2004). The objective of this article is to use PSM principles to create practical recommendations at the regional level, to complement those previously developed for singular facilities. This article compares Strathcona County Emergency Service (SCES) in Alberta with Technical Standards & Safety Authority (TSSA) in Ontario, with respect to safety, facility licensing, permit requirements, risk assessment procedures and land use planning aspects to determine PSM enhancements for SCES. Furthermore, for a better overview, two supplemental provincial organisations in Alberta, namely Alberta Boiler Safety Association (ABSA) and Safety Codes Council (SCC), were also considered. We proposed that SCES could develop more detailed facility-specific licensing procedures, auditing, and inspection. SCES could also provide details of accredited organisations that carry out inspections and audits on their behalf. When reviewing the quantitative risk assessment processes for SCES and TSSA, we recommend that SCES should update their probability data sources used in their cumulative risk assessment study. Based on the authors’ experience and gathered data, the use of additional facility practices such as safety management system, internal audits, and checklists can enhance incident prevention.     

Multi-criteria decision-making considering risk and uncertainty in physical asset management

In this work we present a method for risk-informed decision-making in the physical asset management context whereby risk evaluation and cost-benefit analysis are considered in a common framework. The methodology uses quantitative risk measures to prioritize projects based on a combination of risk tolerance criteria, cost-benefit analysis and uncertainty reduction metrics. There is a need in the risk and asset management literature for a unified framework through which quantitative risk can be evaluated against tolerability criteria and trade-off decisions can be made between risk treatment options. The methodology uses quantitative risk measures for loss of life, loss of production and loss of property. A risk matrix is used to classify risk as intolerable, As Low As Reasonably Practicable (ALARP) or broadly tolerable. Risks in the intolerable and ALARP region require risk treatment, and risk treatment options are generated. Risk reduction benefit of the treatment options is quantified, and cost-benefit analysis is performed using discounted cashflow analysis. The Analytic Hierarchy Process is used to derive weights for prioritization criteria based on decision-maker preferences. The weights, along with prioritization criteria for risk reduction, tolerance criteria and project cost, are used to prioritize projects using the Technique for Order Preference by Similarity to Ideal Solution. The usefulness of the methodology for improved decision-making is illustrated using a numerical example.     

对危化品生产与储存场所定量安全评价的比较研究

分别用道化法和蒙德法对某化工厂的氨合成塔单元进行了定量安全评价,另外还用蒙德法对该厂的液氨储存单元进行了定量安全评价.结果表明：对于火灾、爆炸及毒性危险性共存的单元,应选用蒙德法对其进行安全评价;当被评价单元主要危险物质的毒性较小,并且需要对危险所造成的影响范围、财产损失和停工日有较具体的评价时,应选用道化法对其进行安全评价;当被评价单元主要危险物质具有较大的毒性,并且要求对毒性的危害有较具体的评价时,应选用蒙德法对其进行安全评价.