Dynamic Inherently Safer Modifications: Metric development and its validation for fire and explosion prevention

Of the numerous inherent safety assessment tools, a dynamic metric capable of investigating and incorporating the temporal risk evolution when conducting Inherently Safer Modifications (ISMs) is yet to be established. To this end, this work developed a Dynamic Inherent Safety Metric (DISM) and validated its functionality and viability through a case study. Firstly, the Information-Flow-based Accident-causing Model (IFAM) was adapted to construct the topology of Bayesian Networks (BN). Then, Bayesian deductive reasoning was executed to do crucial risk identification by ranking posterior probabilities. Finally, risk-based ISMs were performed to address the relatively contributing risk factors. The case study results show that the fire and explosion risk decreased by approximately a third after implementing ISMs, thus demonstrating that the modified processing scenario could be inherently safer than the original processing scenario. The newly developed inherent safety metric (i.e., DISM) can assist in temporal risk identification and assessment, and it is expected to function as a novel assessment tool for measuring and comparing the inherent safeness before and after implementing ISMs with simultaneous considerations on the time-varying risk factors.     

Systematic inherent safety and its implementation in chlorine liquefaction process

As a proactive safeguard, inherent safety has been regarded as the top hierarchy for loss prevention and risk management due to its salient features in eliminating or significantly reducing risks at source rather than mitigating them by add-on protections. Simultaneously, various assessment tools have been developed for ranking and selecting inherently safer designs or modifications. However, there still lacks a metric that can systematically incorporate various hazardous factors, which may hinder most industries from utilizing it to a full extent. To address this limitation, this work developed a Systematic Inherent Safety Metric (SISM) for measuring the inherently safer modifications. Firstly, the conceptual framework of SIS was proposed based on 5M1E (man, machine, material, method, measurement, and environment). Subsequently, analytic hierarchy process and fuzzy comprehensive evaluation were adapted to conduct risk identification and assessment. Finally, taking chlorine liquefaction process as a case study, the applicability and efficacy of SIS were validated based on PDCA (plan-do-check-action) cycle. The results show that the SISM value has improved from the relatively dangerous (RD) to the relatively safe (RS) after implementing SIS, thus demonstrating that the revised design is inherently safer than the base design.     

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.     

Qualitative Assessment for Inherently Safer Design (QAISD) at preliminary design stage

Conventional hazard evaluation techniques such as what-if checklist and hazard and operability (HAZOP) studies are often used to recognise potential hazards and recommend possible solutions. They are used to reduce any potential incidents in the process plant to as low as reasonably practicable (ALARP) level. Nevertheless, the suggested risk reduction alternatives merely focus on added passive and active safety systems rather than preventing or minimising the inherent hazards at source through application of inherently safer design (ISD) concept. One of the attributed reasons could be the shortage of techniques or tools to support implementation of the concept. Thus, this paper proposes a qualitative methodology that integrates ISD concept with hazard review technique to identify inherent hazards and generate ISD options at early stage of design as proactive measures to produce inherently safer plant. A modified theory of inventive problem solving (TRIZ) hazard review method is used in this work to identify inherent hazards, whereby an extended inherent safety heuristics tool is developed based on established ISD principles to create potential ISD options. The developed method namely Qualitative Assessment for Inherently Safer Design (QAISD) could be applied during preliminary design stage and the information required to apply the method would be based on common process and safety database of the studied process. However, user experiences and understanding of inherent safety concept are crucial for effective utilisation of the QAISD. This qualitative methodology is applied to a typical batch reactor of toluene nitration as a case study. The results show several ISD strategies that could be considered at early stage of design in order to prevent and minimise the potential of thermal runaway in the nitration process.     

Inherent risk assessment methodology in preliminary design stage: A case study for toxic release

At preliminary design stage, process designers normally lack of information on the risk level from process plant. An inherently safer process plant could be designed if the information of risk levels could be known earlier at the preliminary design stage. If the risk level could be determined, there is a possibility to eliminate or reduce the risk by applying the well-known concept: inherent safety principle. This paper presents a technique to determine the risk levels at preliminary process design stage using a 2-region risk matrix concept. A model to calculate the severity and likelihood of a toxic release accident was developed in Microsoft Excel spreadsheet. This model is integrated with process design simulator, iCON to allow for data transfer during preliminary design stage. 2-region risk matrix is proposed and used to evaluate the acceptability of the inherent risk based on the severity and likelihood rating. If the inherent risk level is unacceptable, modification for improvement can be done using the inherent safety principles. A case study has been carried out to illustrate the benefit of applying this newly developed technique. It was successfully shown that an inherently safer plant could easily be designed by applying this technique.     

化工过程开发中本质安全化设计策略

本质安全化设计是预防人为失误及设备失效、降低化工过程风险应优先采用的技术。在比较传统设计方法与本质安全化设计方法的基础上,讨论了化工过程开发各阶段实现本质安全的机会,认为在开发初期,实施本质安全化的成本低,难度小;通过分析可行性研究、工艺研究、概念设计、基础设计、工程设计等阶段本质安全化设计的影响因素、设计目标和设计方法,探索化工过程开发中本质安全化设计策略,提出了化工过程本质安全化设计流程。通过工艺过程本质安全设计、工艺流程的简化和优化、不同设计方案的本质安全度评估等措施,可提高化工过程本质安全水平。     

Two discrete choice experiments on laboratory safety decisions and practices

IntroductionThe path toward enhancing laboratory safety requires a thorough understanding of the factors that influence the safety-related decision making of laboratory personnel. Method: We developed and administered a web-based survey to assess safety-related decision making of laboratory personnel of a government research organization. The survey included two brief discrete choice experiments (DCEs) that allowed for quantitative analysis of specific factors that potentially influence safety-related decisions and practices associated with two different hypothetical laboratory safety scenarios. One scenario related to reporting a laboratory spill, and the other scenario involved changing protective gloves between laboratory rooms. The survey also included several brief self-report measures of attitude, perception, and behavior related to safety practices. Results: Risk perception was the most influential factor in safety-related decision making in both scenarios. Potential negative consequences and effort associated with reporting an incident and the likelihood an incident was detected by others also affected reporting likelihood. Wearing gloves was also affected somewhat by perceived exposure risk, but not by other social or work-related factors included in the scenarios. Conclusions: The study demonstrated the promise of DCEs in quantifying the relative impact of several factors on safety-related choices of laboratory workers in two hypothetical but realistic scenarios. Participants were faced with hypothetical choice scenarios with realistic features instead of traditional scaling techniques that ask about attitudes and perceptions. The methods are suitable for addressing many occupational safety concerns in which workers face tradeoffs in their safety-related decisions and behavior. Practical Application: Safety-related decisions regarding laboratory practices such as incident reporting and use of PPE were influenced primarily by workers’ perceptions of risk of exposure and severity of risks to health and safety. This finding suggests the importance of providing laboratory workers with adequate and effective education and training on the hazards and risks associated with their work. DCEs are a promising research method for better understanding the relative influences of various personal, social, and organizational factors that shape laboratory safety decisions and practices. The information gained from DCEs may lead to more targeted training materials and interventions.     

Occupational Safety Culture Index (OSCI)——measuring the community and employees awareness,attitude and knowledge towards workplace safety and health in Hong Kong SAR

Promoting occupational safety and health in Hong Kong,Special Administrative Region of China is an important and ongoing mission. As the major organization with statutory responsibilities,the Occupational Safety and Health Council understand the importance to strengthen and cultivate our safety culture. It is widely believed that numbers of occupational related diseases and injuries could be prevented with the improvement of the awareness and attitudes of the employees and the public. Therefore,a comprehensive and in-depth study to monitor the occupational health and safety level and status of the community and working population is needed. Objectives: Our Council has developed the Occupational Safety Culture Index ( OSCI) to measure the current level of community and workplace safety and health awareness,knowledge and attitude. Benchmarking measures of the key safety performance indicators are to be derived thereof. Methods: A territory-wide random telephone survey was conducted to assess the community and employees’awareness,attitude and knowledge in 2008. A structured questionnaire was designed with the content validity and reliability assessed before the survey administration. A series of quality control approaches were also applied to assure the quality of the fieldwork and the reliability of the data. Results: 1,531 eligible participants’data were collected and computed into 2 types of composite indices,Occupational Safety Culture Index ( Community) ( OSCIC) and Occupational Safety Culture Index (Workplace) (OSCIW) . With the maximum score of index at 100,the overall score of OSCIC is 66. 9 and the OSCIW is 61. 3 in Hong Kong. Achievements: OSCI served as an effective management tool to measure the safety culture in Hong Kong. With a representative sample and high quality study control and validated assessment approaches,the OSCI and the sub-indices are reliable indicators to assess the effectiveness of safety culture enhancement strategy and the OSH intervention measures.     

Inherent safety concept based proactive risk reduction strategies: A review

The growing scale and complexity of process industries have brought safety, health, and environmental issues to the forefront. As a result, proactive risk reduction strategies (RRSs) are commonly employed to address these issues by reducing the frequency or mitigating the consequences of potential incidents. Among these strategies, inherent safety, which is a proactive measure of loss prevention and risk management, is considered to be the most effective method. This review aims to provide a comprehensive analysis of RRSs for achieving inherency, as well as techniques for evaluating the performance of inherent safety, health, and environmental aspects. Background information is presented, including the development and implementation of the inherently safer process design, as well as the approaches for achieving inherently healthier and environmentally friendlier processes. Subsequently, the execution approaches and practical applications of other RRSs are discussed to highlight the distinctiveness and benefits of inherent safety. Next, this study examined the characteristics of inherency assessment tools (IATs) based on available information at different process stages. Furthermore, the evaluation methods and historical development of IATs are investigated from the perspectives of safety, occupational health, and environmental considerations, followed by a statistical analysis of IATs. It is concluded that the no-chemical hazards-based IATs have not been extensively studied yet, which may improve the safety level of process plants from the perspective of comprehensive inherency risk reduction. As a way forward, future research opportunities are proposed to promote the implementation of greater optimized risk management.     

Towards an inherently safer bioprocessing industry: A review

The bioprocessing industry is regarded as one of the fastest growing sectors with an estimated compound annual growth rate of 8.6%. The global market for biopharmaceuticals is projected to rise to a market value of USD 727.1 billion by 2025. Due to the unique nature of bioprocessing industries wherein micro-organisms are employed to manufacture the desired products, these processes are prone to additional hazards such as biological hazards and dust explosion amongst others. This necessitates the need to review the existing research in the fields of biotechnology and bioprocessing to reduce/eliminate these hazards and pave the path towards a safer bioprocessing industry. The study involves developing a framework comprising of studying the recent technologies that reduce/eliminate these hazards involved in the bioprocessing industries that include dust explosions, loss of containment of toxic chemicals, loss of containment of biohazard/active product ingredient, fire, and explosion and mapping these technologies with respect to inherent safety principles that include substitution, minimization, moderation and simplification with an overall objective of minimizing the risk associated with bioprocesses and moving towards an inherently safer bioprocessing industry.     

Inherently safer design review and their timing during chemical process development and design

This paper discusses the enhancement of inherent safety review and its implementation in the chemical process development and design. The aim is to update and improve the existing inherently safer design review (ISDR) practices during design of chemical process plant by exploiting major accident cases from the U.S. Chemical Safety Board (CSB) and Failure Knowledge Database (FKD). Although the basic guidelines to conduct ISDR during design phase are available, however they are too general and incomplete. The review criteria and their best timing for application are still missing. This paper attempts to develop the accident-based ISDR for chemical process plant design. The proposed accident-based ISDR is supported with detail review criteria for each phase of process design. The timing of ISDR application is corresponding to the common design tasks and decisions made in the design project. Therefore, timely design review could be done at the specific design task and the findings help designer to make a correct decision making.     

Inherently safer design in offshore oil and gas projects

Like all hazardous installations, inherently safer design (ISD) is one of the key tools in offshore oil and gas projects to minimize risks in offshore facilities. As the life cycle of offshore facilities is relatively short compared with onshore counterparts and there are many projects running every year, the potential is high for raising inherent safety standards and lowering safety risks throughout the offshore industry as old facilities are phased out. This paper gives an overview of offshore facilities and examples of implementation of ISD. Good examples of ISD are numerous. Industry guidance on ISD implementation abound. Yet, the systematic implementation of it in the industry is patchy. There are many reasons for factors which impede the effective, efficient and consistent implementation of ISD in projects. This paper describes some of them and proposes solution to address them. They include (a) the effective integration of ISD into hazard management systems with appropriate language to engage all disciplines in projects, (b) the phasing of resources to enable the project to capture ISD measures which are only available during early phases, (c) application of appropriate ISD goals and ISD performance metrics at various stages and (d) the appropriate use of quantified risk assessment to support ISD.     

At-risk behaviour analysis and improvement study in an academic laboratory

Academic laboratories contain inherently substantial risk conditions that students could expose to chemical and physical hazards. Procedures and guidelines related to laboratory safety are commonly available for students to adhere. However, many injuries and accidents or even fatalities are reported due to students’ violated safety practices while working in the laboratory. There was no reported proactive method or systematic technique to monitor and control students’ at-risk behaviour in the laboratory. This paper presented a program known as laboratory at-risk behaviour and improvement system (Lab-ARBAIS) to monitor and control students’ at-risk behaviours in the laboratory. Lab-ARBAIS used computer database for data acquisition and analysis on students’ at-risk behaviours observed. Pre-program questions on students’ at-risk behaviours that frequently violated safety regulations were utilized by observers to give observation feedback. The collected feedback was analysed and the results were posted in students’ portal to allow everyone to acknowledge their safety habits and practices. The routine observations and posted results are to instill a psychology effect in student’s habitual safety practices by reminding them on their frequently violated safety regulations. The implementation of the Lab-ARBAIS program to chemical engineering laboratory as a case study had shown a significant improvement on students’ frequent at-risk behaviours. The Lab-ARBAIS can easily be adopted in any academic laboratories to manage students’ at-risk behaviours to ensure safe work environment. With minor enhancement, the Lab-ARBAIS can easily be extended to be used in industrial laboratories.     

基于模糊综合评价的化工工艺本质安全指数研究

建立化工工艺的本质安全评价指标体系,包括可燃性、爆炸性、毒性、反应性、温度、压力、储量等7个指标。为解决前人指数法中的边界波动效应,采用模糊综合评价建立化工工艺本质安全评价指数模型,确定各指标的权重、危险分级及对各分级的隶属函数。以甲基丙烯酸甲酯的5条工艺路线为例进行分析,结论与前人提出的指数方法的评价结果相吻合,表明该指数方法可以用来进行化工工艺的本质安全评价,以指导设计初期的本质安全型工艺路线选择。     

Solvent design and inherent safety assessment of solvent alternatives for palm oil recovery

The concept of inherent safety is important in developing an inherently safer and user-friendly process. This paper discusses a new integrated approach of computer-aided product design and inherent safety assessment. Computer-aided Molecular Design (CAMD) approach was utilized in this work to identify potential alternative to n-hexane, the widely used industrial solvent in extracting residual palm oil from pressed palm fibre. The formulation of solvent mixtures was optimized to meet the targeted physical properties before being tested using the Soxhlet Extraction method. Inherent safety assessment to assess the solvent's flammability, toxicity, reactivity, and explosiveness was conducted on the new solvent mix, Mixture 1 (n-hexane + ethanol), Mixture 2 (n-hexane + acetone) and Mixture 3 (n-hexane + n-butanol). It was found that Mixture 1 and 3 are safer than n-hexane and able to extract more oil than n-hexane and Mixture 2. However, the utilization of the solvent is dependent on the end product from the residual palm oil.     

Developments in inherent safety: A review of the progress during 2001–2011 and opportunities ahead

This paper reviews the progress in inherent safety. A summary of the historical developments up to the year 2000 is first presented which sets the stage for a review of the key developments during the first 11 years of the 21st century. A landscape of inherent safety is developed by mapping publications on two coordinates. The first coordinate, the risk coordinate, indicates if the focus of a paper relates to inherent hazard or to the likelihood of events. The second coordinate, the management coordinate, focuses on the ways and means to understand and assess inherent safety. Out of the 187 papers that have appeared over this 11-year period, 131 pertained to developments in inherently safer design; these have been organized on the proposed landscape. The rest introduce the basic concepts of inherent safety and address its incorporation into regulation, education and accident investigation. These along with the application of inherent safety in industry are also discussed. We conclude with a discussion on recent trends in industry and suggest directions for future research.     

机械行业安全管理评价模式研究

安全管理评价模式繁多在各行业中得到广泛的应用。笔者运用安全工程的基本理论,基于MORT和SMORT方法,从综合及具体管理两方面提出10项影响企业安全水平的管理因素,并对该类因素进行层次分析,开发一套机械行业的安全管理评价模式;采用问卷形式对该评价模式进行了测试,选择重庆市3家有代表性的机械企业,运用层次分析法对测试结果进行计算分析,验证安全管理评价模式的有效性和可行性,并对企业的安全管理提出了建议。     

Assessing the hazards from a BLEVE and minimizing its impacts using the inherent safety concept

Many worlds' major process industry accidents are due to BLEVE such as at Feyzin, France, 1966 and San Juan Ixhuatepec, Mexico City, 1984. One of the approaches to eliminate or minimize such accidents is by the implementation of inherently safer design concept. This concept is best implemented where the consequence of BLEVE can be evaluated at the preliminary design stage, and necessary design improvements can be done as early as possible. Thus, the accident could be avoided or minimized to as low as reasonably practicable (ALARP) without resorting to a costly protective system. However, the inherent safety concept is not easy to implement at the preliminary design stage due to lack of systematic technique for practical application. To overcome these hurdles, this paper presents a new approach to assess process plant for the potential BLEVE at the preliminary design stage and to allow modifications using inherent safety principles in order to avoid or minimize major accidents. A model known as Inherent Fire Consequence Estimation Tool (IFCET) is developed in MS Excel spreadsheet to evaluate BLEVE impacts based on overpressure, radiation heat flux and missile effects. In this study, BLEVE impacts are the criteria used as the decision-making for the acceptability of the design. IFCET is integrated with iCON process design simulator for ease of data transfer and quick assessment of potential BLEVE during the design simulation stage. A case study was conducted to assess of potential BLEVE from a propane storage vessel at the design simulation stage using this new approach. The finding shows promising results that this approach has a potential to be developed as a practical tool.     

油库火灾爆炸事故多米诺效应定量评价

引入多米诺效应定义,介绍多米诺效应定量评价的方法。结合具体实例对油库进行火灾爆炸事故的风险分析,给出事故多米诺效应定量评价的具体程序。通过油库火灾爆炸事故多米诺效应评价,得出油库事故的升级因素和导致事故扩大的途径,并指出相应的多米诺效应控制措施。与传统的评价方法相比,多米诺效应评价方法可预测次生事故发生情况和发生概率及后果,从而可以有针对性地采取相应的预防措施,预防事故多米诺效应,降低次生灾害的发生率,提高油库的本质安全程度。     

北京市危险化学品企业安全生产风险评估分级研究

为对北京市危化品企业基本情况的全面掌握,开展了危险化学品企业安全生产风险评估分级研究,借鉴国外经验和国内有关科研成果,提出了固有风险和动态风险相结合的危化品安全生产风险评估方法。固有风险为企业的基本风险水平,主要由危险化学品物质量、工艺水平、安全监控和周边环境决定,为共性指标;动态风险,反映企业安全生产管理绩效的水平,主要包括安全基础管理和现场管理,为个性指标,不同企业类型,评估动态风险指标有差异。从大量数据中抽取了最能反应企业安全生产状态的指标因素,通过专家组打分法和层次分析法确定评价因素的权重,该评估方法具有较强的实用性和可操作性,是本质安全和安全绩效的创新结合,为企业安全生产评估分级提供了新思路。通过分级,按照"风险优先"原则,政府部门实行差别监管,降低安全监管成本,促进危险化学品安全生产工作向规范化、科学化转变。同时,研制了危化品企业安全生产风险分级系统,为建立北京市危化品企业风险分级数据库奠定了基础。