Risk-based maintenance (RBM): a quantitative approach for maintenance/inspection scheduling and planning

The overall objective of the maintenance process is to increase the profitability of the operation and optimize the total life cycle cost without compromising safety or environmental issues. Risk assessment integrates reliability with safety and environmental issues and therefore can be used as a decision tool for preventive maintenance planning. Maintenance planning based on risk analysis minimizes the probability of system failure and its consequences (related to safety, economic, and environment). It helps management in making correct decisions concerning investment in maintenance or related field. This will, in turn, result in better asset and capital utilization.

This paper presents a new methodology for risk-based maintenance. The proposed methodology is comprehensive and quantitative. It comprises three main modules: risk estimation module, risk evaluation module, and maintenance planning module. Details of the three modules are given. A case study, which exemplifies the use of methodology to a heating, ventilation and air-conditioning (HVAC) system, is also discussed.     

Engineering for Sustainable Development (ESD) in Bio-Diesel Production

Engineering for sustainable development (ESD) is an integrated systems approach, which aims at developing a balance between the requirements of the current stakeholders without compromising the ability of the future generations to meet their needs. This is a multi-criteria decision-making process that involves the identification of the most optimal sustainable process, which satisfies economic, ecological, social criteria as well as safety and health requirements. Certain difficulties are encountered when ESD is applied such as ill-defined criteria, scarcity of information, lack of process-specific data, metrics and the need to satisfy multiple decision makers. To overcome these difficulties ESD can be broken down into three major steps, starting with the life cycle assessment (LCA) of the process, followed by generation of non-dominating alternatives, and finally selecting the most sustainable process by employing an analytic hierarchical selection process. This methodology starts with the prioritization of the sustainability metrics (health and safety, economic, ecological and social components). Then the alternatives are subjected to a pair-wise comparison with respect to each Sustainable Development (SD) indicator and prioritized depending on their performance. The SD indicator priority score and each individual alternative's performance score together are used to determine the most sustainable alternative. In this paper, the analysis approach and metrics for ESD are applied to bio-diesel production.     

Methodology for the quantification of toxic dispersions originated in warehouse fires and its application to the QRA in Catalonia (Spain)

A tool for the quantification of the consequences of toxic dispersions coming from fires in warehouses has been developed. This tool is expected to be applied in the framework of the risk assessment in Catalonia, specifically in the Quantitative Risk Assessment. The present study is based on the criteria gathered in the technical guide BEVI 3.2 and the methodology CPR-15 used in the Netherlands. Hence, the approach performed accepts the main body of the foresaid methodology but implements a different and free source dispersion model, a modified Gaussian model that takes into account the warehouse effect. In the work conducted, a historical analysis of accidents involving fire in warehouses has been performed in order to justify the importance of assessing their potential toxic dispersions. Furthermore, the tool has been tested in different case studies providing results that have been compared with other methodologies, observing similar results that can be useful for the stakeholders and decision makers in the framework of the risk assessment.     

基于生态安全约束的再生利用项目规划设计方案决策

为确保我国旧工业建筑(区)再生利用项目方案设计阶段免受生态破坏与环境污染等因素的影响,提出了"生态安全约束"这一概念。考虑到决策者面对收益和损失的不同态度引入了前景理论,建立了生态安全约束下基于前景理论再生利用项目规划设计方案决策模型。首先,构建了包含总体规划、建筑设计、传承保护等因素的决策指标体系,并采用AHP与熵权相结合的方法计算权重,使得权重计算结果不仅体现了决策者的主管意愿,也反映了再生利用项目的客观规律;其次,以决策者预期值作为参考点给出期望矢量,将不同属性的决策数据信息规范化处理得初始决策矩阵,再根据指标间相对参考点的差值建立前景决策矩阵,通过计算各方案的综合前景值以确定最优方案。最后,通过北京首钢、云南871、陕西老钢厂、太原锅炉厂等5个实例的再生利用项目规划设计方案决策过程加以验证。结果表明,模型计算过程清晰,结果可信度高,验证了模型的合理性和科学性,可为规划设计阶段有效控制生态环境破坏与厂区环境污染提供新的思路。     

基于演练决策文本分析的决策者分类及应急决策差异研究

为研究特大地震初期的高层决策行为，通过演练模拟决策者在可得灾情信息下进行决策部署的情形，采集参演决策者独立确认的最终决策文本为样本，对比分析样本对草案修改的方式和程度，将决策者分为独立型、合作型和依赖型。结构化处理提取样本的决策任务，分析与灾情信息及决策建议的相关性。结果表明:在高层决策者中合作型人数比例最高，群组内决策差异较小，质量相对稳定；独立型决策者偏好主观判断，对灾情的关注以及草案漏洞的审查等指标明显低于其他类型；依赖型决策者在使用合理化建议的前提下易做出高质量决策，但在决策支持失误而非漏洞的条件下，能否保证决策质量有待进一步验证。     

From hanger-on to trendsetter: Decision making on a major safety initiative in a steel company maintenance department

This paper describes a case study of decision making in a steelworks maintenance department, which led to the introduction of a major initiative to improve safety performance. The origin of the decision process lay, however, not with safety, but with an earlier decision to consider outsourcing the maintenance department. When it was decided that this was not feasible a new General Manager was appointed to turn around the performance of the now demoralised department. In his search for solutions and the external developments taking place in parallel he found an initiative which seemed to link his main concerns with a parallel concern for safety improvement. The philosophy behind it and the vision and strategy which was developed to carry it led to a much more participative approach, driven by clearly defined key performance indicators. Safety was chosen as the lead objective. This paper describes the development of the decision process and briefly explains its results.     

J-value analysis of different regulatory limits for workers and the public

The J-value technique allows an objective determination to be made of the resources that should be applied cost effectively to improve heath and safety. This is essential if capabilities are to be employed optimally and risks reduced in a way that reflects their severity. Although other considerations such as good practice and socio-political influences may affect a final decision on the resources to be sanctioned, the incorporation of these additional factors should be made transparent if the decision is no longer to be based on cost effectiveness. The J-value provides an objective criterion by which to judge when “reasonable practicability” has been achieved in committing resources for safety improvement, which is the legal requirement under health and safety law in the UK.Moreover, the J-value methodology also allows other related issues to be addressed objectively. Regulatory bodies apply different limits for workers and the general public, with higher risks being permitted for workers. Although a factor of about 10 has been used in several contexts, no objective rationale has been developed for this particular figure until now. However, it is shown that application of the J-value analysis can provide a justification for a ratio of workers’ risk to public risk of approximately this size if certain reasonable assumptions are made. Thus the paper provides the first quantitative explanation for the different levels of protection demanded by regulators nationally and internationally for workers and public.     

基于城乡统筹的公共安全规划研究——以长株潭城市群为例

以长株潭城市群公共安全规划为研究对象,本着"资源节约、环境友好"两型社会建设的要求,从保护人的安全出发,以实现城乡统筹的风险控制和风险减缓设施建设。长株潭城乡公共安全,规划包括:重大危险源安全规划编制、开敞空间及综合避灾场地规划以及区域综合防灾规划3个方面,强调对城乡统筹的安全内容;该安全规划既是政治经济发展的战略要求,也是政府职能部门的管理要害,还是城乡居民基本的生存保障,具有前瞻性,以完善技术设计来降低风险,同时在管理上加强协调性和拓展性。     

Cost-based fire risk assessment in natural gas industry by means of fuzzy FTA and ETA

Fire is the most prevalent accident in natural gas facilities. In order to assess the risk of fire in a gas processing plant, a fault tree analysis (FTA) and event tree analysis (ETA) has been developed in this paper. By utilizing FTA and ETA, the paths leading to an outcome event would be visually demonstrated. The framework was applied to a case study of processing plant in South Pars gas complex. All major underlying causes of fire accident in a gas processing facility determined through a process hazard analysis (PHA). Fuzzy logic has been employed to derive likelihood of basic events in FTA from uncertain opinion of experts. The outcome events in event tree has been simulated by computer model to evaluate their severity. In the proposed methodology the calculated risk has the unit of cost per year which allows the decision makers to discern the benefit of their investment in safety measures and risk mitigation.     

How do different process options and evaluation settings affect economic and environmental assessments? A case study on methyl methacrylate (MMA) production processes

We present an investigation on how economic and environmental assessment results change when different process options or evaluation settings are considered. As the main case study the production technology of methyl methacrylate (MMA) is investigated. Six commercial processes using different reaction routes are modelled and evaluated with respect to their economic and environmental performance. On these six base case models different process options and evaluation settings are considered and the resulting impacts on the assessment results are quantified. Major findings of the study are that the more decision-variables become fixed, the smaller becomes the impact of the decisions still to be taken—but not only with respect to the economic performance but also with regard to the environmental assessment result. Along the process development steps the potential impacts on the economic and environmental performance decrease to the same degree. The results obtained for the evaluation settings do not show such a systematic pattern as those for the process options. This finding indicates that decision makers face many options in the economic and especially the environmental assessment of chemical processes which might lead to quite different magnitudes in variability due to either the choice of method or the choice of method parameters. This paper demonstrates that the resulting variability might be crucial with respect to the decision making outcome.     

Firm relocation as a potential solution for environment improvement using a SWOT-AHP hybrid method

Global economic expansion and increasing concentration of people in the large cities, especially in developing countries leads to some environmental issues such as air pollution. Relocation of the firms as a great air pollutant can be an appropriate alternative for diminishing these pollutions. Yet, there is a lack of research about factors precluding firm relocation with respect to decision making factors when determining whether or not to relocate. Thus, the purpose of this case study is to examine firm relocation decision-making factors and to apprehend the role of environment issues in making them using a combination of SWOT matrix and Analytic Hierarchy Process (AHP). The combination yields analytically determined priority factors and makes them commensurable. The results indicated that decision makers at this firm consider weaknesses, more importantly than strengths, opportunities and threats. Specifically, eradicating from a large market is the most significant factor for decision makers and notably diminishing air pollution as a governmental concern ranked third.     

基于安全规划要素表的化工园区安全规划研究

化工园区的蓬勃发展为我国经济发展做出了重要贡献,与此同时,近年来化工园区的安全状况不容乐观,事故时有发生,缺乏有效的安全规划是事故发生的原因之一,而安全规划依据不完善、操作性不强是化工园区安全规划难以有效落实的重要原因。针对此问题,笔者依据《中华人民共和国安全生产法》等相关法律法规、标准规范,并借鉴国内外化工园区安全规划的先进经验,提炼出化工园区安全规划核心要素,将安全规划要素表作为化工园区安全规划的直接依据,该依据内容具体、较为完整。同时,基于安全规划要素表,本文重点研究了在化工园区生命周期内各阶段应重点规划的内容,指导化工园区各阶段的安全建设以及应重点注意的问题,以期加强化工园区的整体安全。     

危险化学品企业外部安全防护距离监管存在问题及对策

国内外许多重大事故教训表明要危险化学品企业必须与外部脆弱性目标之间设置合理的安全防护距离。目前在危险化学品企业外部安全防护距离的监管过程中存在许多问题,如缺乏上位法的支撑,未纳入城市规划控制程序,缺乏专门的安全防护距离标准,事故隐患企业搬迁难,以及公众参与不足等。造成这些问题的原因有城市发展的压力,政府监管的缺失,部分企业盲目扩建、改造,周边区域违规开发建设。危险化学品企业的外部安全防护距离问题涉及到危险化学品企业、周边开发单位、公众以及政府四个主要利益相关方,目前所遇到的问题是土地资源在城市经济社会快速发展与公众安全需求提高之间矛盾下的必然结果。在立足国情借鉴国外做法的基础上,本文提出一些综合性策略和针对新建项目和现有企业的措施建议,目前解决危险化学品企业安全防护距离问题解决的关键是将危险化学品企业及其周边区域的土地利用规划的安全控制纳入城市规划许可程序中,以及利益相关方之间相互协调机制的建立。     

机场运行安全规划中安全指标体系的构建

通过对机场运行安全规划中安全指标体系定位的分析,遵循可接受、可实施、可量化、可调控的原则,以结果和过程管理思想为指导,结合风险管理理论,构建机场运行安全规划中的安全指标体系。这个体系包括3个子体系,它们分别涉及运行安全的结果、运行安全的业务过程和运行安全管理绩效3个方面。其中,有关运行安全结果的子指标体系包括事故、事故征候、其他不安全事件3个维度11项指标;有关运行安全业务过程的子指标体系包括飞行区管理、机坪运行管理等7个维度20项指标;有关安全管理绩效的子指标体系包括安全政策与目标、风险管理等4个维度7项指标。     

Fuzzy AHP approach to selection problems in process engineering involving quantitative and qualitative aspects

Selection problems are common in process engineering. In most cases, it is necessary to rank alternatives based on multiple criteria (e.g., cost, safety, environmental impact), which are often conflicting. In addition, some criteria may be fundamentally difficult to quantify due to data scarcity, in which case subjective assessments need to be used as a proxy. Decision analysis tools such as the analytic hierarchy process (AHP) are useful to ensure decision-making is done rationally. In this work, we propose a fuzzy AHP variant, wherein pairwise comparison of decision elements by domain experts is expressed with triangular fuzzy numbers. This approach allows the degree of confidence of the expert to be quantified explicitly; it also allows inconsistencies in judgment to be reconciled within the bounds of the fuzzy numbers to generate reasonable values for the weighting factors. We demonstrate the methodology on three case studies, involving the comparison of different types of chlor-alkali electrolytic cells, CO₂ capture techniques in cement plants and wastewater treatment options for municipal wastewater.     

Investing in safety an analytical precautionary principle

PROBLEM: Governments and businesses must respond to increasing safety requirements and balance the associated costs with productivity and competing pressures. METHOD: A real options approach has been introduced for decision making in the private sector; this approach is adapted for regulatory decisions that can involve irreversible and uncertain safety impacts, social costs that differ from private costs, and differences in perception among the stakeholders. RESULT AND IMPACT ON INDUSTRY AND GOVERNMENT: The outcome is an economic decision gage that determines if it is optimal to invest in safety even if the estimated costs significantly exceed the estimated benefits. Applications potentially include safety decisions related to aviation, ground transportation, pipelines, nuclear facilities, natural disaster planning, and terrorism, among others.     

基于非结构模糊决策的中国药品安全管理体系研究

基于安全管理理论和中国药品管理实践,通过专家意见和社会调查,确定中国药品安全管理的要素和决策标准;运用非结构模糊决策方法确定中国药品安全管理中各重要要素的权重,从而探索中国药品安全管理体系;对体系的不同要素进行排序。研究表明:影响中国药品安全管理的主要要素有,安全交易、许可制度、药品利润率、可追溯体系、药物警戒、应急管理;决策标准是,成本、经济水平、硬件条件、从业人员素质、消费者观念;重要性排序是,可追溯体系、许可制度、药物警戒、应急管理、安全交易、药品利润率。药品安全管理体系的建立和要素排序为政府监管提供了科学依据。     

Safety,reliability and worker satisfaction during organizational change

The research presented in this paper was carried out in four process industry plants in the Netherlands, to identify factors that have the potential to increase safety and reliability while maintaining or improving job satisfaction. The data used were gathered as part of broader trajectories in these firms, aiming at the simultaneous improvement of productivity and safety, while maintaining or improving worker satisfaction. The results show that participative leadership is crucial for combining an increase in safety and reliability with job satisfaction. Participative leadership has a positive effect on job satisfaction and through proper maintenance also on the prevention and absence of disturbances and on the reliability of the production process. The results of this research show the importance of participative leadership for safety, reliability and worker satisfaction, especially during organizational change. Other important factors are operator competences, teamwork, proper handling of variance and disturbances, and proper maintenance. It also confirms that apart from technological factors associated with proper maintenance, people and team related factors are important for increasing safety and reliability in the process industry, especially for being prepared for disturbances and to be able to cope adequately with them.     

Mitigation of operational failures via an economic framework of reliability,availability, and maintainability (RAM) during conceptual design

Abnormal process situation may lead to tremendous negative impact on sustainability, wellbeing of workers and adjacent communities, company's profit, and stability of supply chains. Failure of equipment and process subsystems are among the primary causes of abnormal situations. The conventional approach in handling failure-based abnormal situations has usually focused on operational strategies. Such an approach overlooks the critical role of process design in mitigating failure, while simultaneously considering the effects of such failure on process economic performance. The aim of this work is to introduce a systematic methodology that accounts for failure early enough during the conceptual design stages. Once a base-case design is developed, the methodology starts by identifying the sources of failure that are caused by reliability issues including equipment, operational procedures, and human errors for a given process system or subsystem. This allows for the identification of critical process subsystem(s) that are more failure-prone or cause greater downtime than other subsystems. Bayesian updating and Monte Carlo techniques are utilized to determine the appropriate distributions for the failure and repair scenario(s), respectively, in question. Markov analysis is used to determine the system availability. Next, the process revenue is described as a function of inherent availability. The effects of failures are incorporated into profitability calculations to establish an economic framework for trading off failure and profitability. In the proposed framework, the economic potential of alternative design scenarios is evaluated and an optimization formulation with the objective of maximizing incremental return on investment (IROI) is utilized to make a design decision. A case study on an ethylene plant is solved to demonstrate the applicability and value of the proposed approach.