Calculation of Fire and Explosion Index (F&EI) value for the Dow Guide taking credit for the loss control measures

The Dow Fire and Explosion Index (F&EI) is universally used in evaluating the hazard category of a process plant, area of exposure, expected losses in case of fire and explosion, etc. In the current procedure, the effects of the loss control measures (LCMs) on the F&EI value are not taken into account. This makes the plant look more hazardous, makes it more spread out, requires more elaborate emergency measures and alarms the public and the civil administration more than is necessary. It also affects the insurance premium.We suggest taking the effects of the LCMs into account in the F&EI value. We call this the ‘Offset F&EI’ value. It favorably affects all the above items, and other related ones. To do this, we have developed the relevant equations and have proved the efficacy of the Offset F&EI by means of an example.     

Taking Credit for Loss Control Measures in the Plant with the Likely Loss Fire and Explosion Index (LL-F&EI)

This communication proposes a new relationship for estimation of the damage factor (DF) used in the Dow Fire and Explosion Index (F&EI). The proposed new relation more clearly shows how the damage factor depends on other factors in the F&EI, such as material factor (MF) and Process Unit Hazards Factor, and leads to the definition of a new index which accounts for loss control measures implemented in the plant, and thus gives a measure of risk. Analysis shows that three types of relations exist between DF and Process Unit Hazards Factor depending on the size of the MF—low, medium or high. Further analysis shows, that the procedure in the current F&EI Guide may overestimate the DF for a very low MF and moderate to high Process Unit Hazards Factor.The analysis leads to the definition of the Likely Loss Fire & Explosion Index, which provides an estimate of risk of losses from fires and explosions as well as degrees of risk similar to the estimate of hazards and degrees of hazard associated with the Fire & Explosion Index.     

The integration of Dow's fire and explosion index (F&EI) into process design and optimization to achieve inherently safer design

For the processing industries, it is critically to have an economically optimum and inherently safer design and operation. The basic concept is to achieve the best design based on technical and business performance criteria while performing within acceptable safety levels. Commonly, safety is examined and incorporated typically as an after-thought to design. Therefore, systematic and structured procedure for integrating safety into process design and optimization that is compatible with currently available optimization and safety analysis methodology must be available.The objective of this paper is to develop a systematic procedure for the incorporation of safety into the conceptual design and optimization stage. We propose the inclusion of the Dow fire and explosion index (F&EI) as the safety metric in the design and optimization framework by incorporating F&EI within the design and optimization framework. We first develop the F&EI computer program to calculate the F&EI value and to generate the mathematical expression of F&EI as a function of material inventory and operating pressure. The proposed procedure is applied to a case study involving reaction and separation. Then, the design and optimization of the system are compared for the cases with and without safety as the optimization constraint. The final result is the optimum economic and inherently safer design for the reactor and distillation column system.     

基于道化学法的大型合成氨装置安全评价

根据道化学公司火灾、爆炸危险指数的基本原理。用VH6．0开发的安全评价软件DowSE1．0，对某大型合成氨装置进行安全评价，得出其安全措施补偿前后的火灾、爆炸指数F＆EI以及危险暴露面积，危害系数，危险等级，实际可能财产损失程度等指数。结果表明。合成氨装置中实际最大可能财产损失值都没有超过200万美元，气化系统在合成氨装置中实际最大可能财产损失值占损失替换值比例高达53％，超过了10％的相对危险值界限。说明在引进国外技术时应注重其安全防范配套措施消化吸收，并结合实际采取切实可行的安全措施，降低合成氨装置的风险程度。     

Risk assessment and risk reduction of an acrylonitrile production plant

Reducing accident occurrence in petrochemical plants is crucial, thus appropriately allocating management resources to safety investment is a vital issue for corporate management as international competition intensifies. Understanding the priority of safety investment in a rational way helps achieve this objective.In this study, we targeted an acrylonitrile plant. First, Dow Chemical's Fire and Explosion Index (F&EI) identified the reaction process as having the greatest physical risk. We evaluated the severity of accidents in the reaction process using the Process Safety Metrics advocated by the Center for Chemical Process Safety (CCPS); however, this index does not express damages a company actually experience. To solve this problem, we proposed a new metric that adds indirect cost to CCPS metrics. We adopted fault tree analysis (FTA) as a risk assessment method. In identifying top events and basic events, we attempted to improve the completeness of risk identification by considering accidents from the past, actual plant operation and equipment characteristics, natural disasters, and cyber-attacks and terrorist attacks. Consequently, we identified the top events with high priority in handling because of serious accidents as fire/explosion outside the reactor, fire/explosion inside the reactor, and reactor destruction. The new CCPS evaluation index proposed in this study found that fire and explosion outside the reactor has the highest severity. We considered the creation of the fault tree (FT) diagram of the top event, estimating the occurrence probability, and identifying the risk reduction part and capital investment aimed at risk reduction. As an economically feasible selection method for risk reduction investment, using the difference in loss amounts before and after safety investments indicated investment priority.     

Inherent thermal runaway hazard evaluation method of chemical process based on fire and explosion index

Thermal runaway hazard assessment provides the basis for comparing the hazard levels of different chemical processes. To make an overall evaluation, hazard of materials and reactions should be considered. However, most existing methods didn't take the both into account simultaneously, which may lead the assessment to a deviation from the actual hazard. Therefore, an integrated approach called Inherent Thermal-runaway Hazard Index (ITHI) was developed in this paper. Similar to Dow Fire and Explosion Index(F&EI) function, thermal runaway hazard of chemical process in ITHI was the product of material factor (MF) and risk index (RI) of reaction. MF was an indicator of material thermal hazards, which can be determined by initial reaction temperature and maximum power density. RI, which was the product of probability and severity, indicated the risk of thermal runaway during the reaction stage. Time to maximum rate under adiabatic conditions and criticality classes of scenario were used to indicate the runaway probability of the chemical process. Adiabatic temperature rise and heat of the desired reaction and secondary reaction were used to determine the severity of runaway reaction. Finally, predefined hazard classification criteria was used to classify and interpret the results obtained by this method. Moreover, the method was validated by case studies.     

HAZOP-FTA综合分析方法在煤化工装置中的应用

为提高煤化工生产工艺安全水平,降低事故发生的可能性和严重程度,有必要对其工艺过程中的危害因素进行全面系统的辨识分析。以某甲醇公司煤制甲醇气化装置为例,运用HAZOP方法准确识别工艺偏差危害因素,定性分析偏差产生的可能原因、后果及现有安全措施;在此基础上,运用FTA方法,获得顶上事件发生概率值和基本事件重要度结果,实现工艺设备设施危害因素的定性与定量分析,提出有针对性的建议安全措施。两种方法的综合应用,给予煤化工企业系统安全分析一种新的思路,使其得到更加科学准确的危险性分析结果,为企业开展危害因素的分级管理,有效预防和减少事故的发生提供了理论支撑。     

Quantification of inherent safety aspects of the Dow indices

The Dow fire and explosion index (F&EI) and chemical exposure index (CEI) have been successfully implemented in a Visual Basic environment as a tool for the inherent safety assessment of chemical processes. Subprograms were developed to quantify the inherent safety aspects of the Dow indices. These aspects are presented graphically with the indices on the vertical axis and an inherent safety indicator on the horizontal axis. Dow indices of the MIC storage unit involved in the Bhopal disaster were evaluated to quantify the effects of process temperature, pressure and inventory of hazardous materials on the index values.

As operating pressure was reduced, the F&EI decreased in accordance with the principles of inherent safety. The change in F&EI due to reduction of inventory was more significant than that resulting from pressure reduction. The results show that the F&EI change, given the same range of the independent variables (quantity of hazardous materials, operating temperature and pressure), is larger when a unit in the process area is evaluated compared to a unit in a storage area (tank farm). Reduction of the inventory of hazardous materials had no direct effect on the CEI for vapor releases, whereas the size of the hole diameter impacted the CEI to a great extent. However, there is a significant change in the CEI as the inventory of materials decreases for liquid releases involving temperatures above their flash and boiling points. Pressure reduction decreases the CEI, whereas temperature reduction leads to an increase in the CEI when these parameters are treated independently.     

企业危险源风险管理方法研究

简要分析危险源管理现状,以及风险控制、风险的财务安排、保险等风险管理方法。阐述如何将风险管理理念引入到危险源管理中,将风险管理与企业危险源管理相结合,以提高危险源的管理水平。重点论述利用最小化代价原则紧抓企业安全管理;利用风险集中原理,合理使用安全投入资金;利用风险转移方法,降低事故率;合理使用财务方法,减小事故引发的损失。从而实现预防事故、减少损失、合理安排资金、保证企业的可持续发展。     

Global process safety incidents in the pharmaceutical industry

The objective of this research is to analyse global process safety incidents within the pharmaceutical industry in terms of their consequences and factors contributing to the incidents. There were 73 process safety incidents leading to 108 fatalities found between 1985 and 2019. Trends between the number of incidents, number of fatalities, location, and contributing factors were identified and summarized. The most reported fatalities occurred in 2018 & 2019. 83% of fatalities occurred in China and India. Explosions were associated with 71% of incidents, which resulted in 89% of fatalities. For most of the international incidents, incident investigations were not available and thus insufficient details were available to determine the causes. Contributing factors were available or estimated from available data for about half of the incidents, with the following most common: hazard awareness & identification; operating procedures; design; safeguards, controls & layers of protection; safety culture; and preventive maintenance. These findings can be used as a basis to improve process safety performance in the pharmaceutical industry.     

Got a risk reduction strategy?

Process safety can be viewed as part of a triad that supports safety in a petrochemical facility. The other two parts are OSHA-type people safety (slips, falls, etc.) and industrial hygiene. The paper will look at process safety from a top down, plant centric view. Process safety can be distilled down to the basic concept of risk reduction. If we reduce risk, our facility will be safer. The obvious problem is that we have potential risks everywhere so how are we going to reduce all these risks to an acceptable level. Clearly we need a strategy or to use a less fancy word – a plan.Too many times it is easy to concentrate on certain aspects such as safety instrumented systems (SIS), layer of protection analysis (LOPA), behavioral safety, prevention, etc. and lose track of the whole picture of what risk reduction entails in a plant.This paper will look at risk reduction in a facility from a plant viewpoint and will cover the details and concepts of risk reduction across a wide spectrum of plant functionalities – safety climate and culture, process safety management, mechanical integrity and risk, layers of protection in risk reduction, loss of containment/hazard relationship, the risk reduction bow-tie diagram, developing a risk reduction strategy, risk reduction strategy elements, and sustainability.It will also discuss some key concepts in dealing with risk reduction in general.     

Metrics and analytics for process hazard analysis

Process hazard analysis (PHA) studies (e.g. HAZOP) identify hazard scenarios and each scenario is examined individually to decide whether risk reduction measures are needed. However, much more can be done to benefit from the contents of studies.PHA studies contain so much data that a manual review is precluded from yielding insights into their results. Fortunately, valuable information can be extracted using metrics and analytics that consider all the contents of a PHA study. The management of safety, operability, reliability, utilization, and loss prevention can all be improved.Metrics evaluate the contents of PHA studies to provide insights into the safety of processes and the quality of studies. Measures of process safety and study quality can be compared with norms to identify possible departures that may need to be addressed.Rather than focusing decision making on the risks of individual hazard scenarios, as is common practice, analytics enable a deeper analysis of the entire set of scenarios for a process. This enables better decisions to be made on where and how risk reduction resources should be allocated. Analytics can also be used to prioritize maintenance, training, and other activities.Various analytics and metrics for PHA studies are described together with examples that illustrate their use.     

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.     

钻探工程施工中危险源辨识、风险评价及其控制

对钻探工程施工中存在的危险、危害因素进行了辨识和分析,采用预先危险性分析方法及安全因素影响风险评价方法对施工过程中危险源的危险等级和安全因素影响等进行了分析和评价,针对重大危险源采用了安全技术和安全管理控制措施。首先对能量危害物质、失控(包括生产、控制、安全装置和辅助设施等故障及人员失误)、管理缺陷及客观因素进行危险源辨识;第二,评价危险源危害因素主次;第三,采用安全技术和安全管理措施有效地对车辆伤害、登高作业、防雷安全、用电安全、机械安全及预防自然灾害(火灾)等重大危险源进行控制。通过实践表明,福建省121地质大队采用该方法对钻探工程项目的危险源进行了有效地控制,实现了钻探安全生产。     

3-Parameters SPW technique: A new method for evaluation of target safety integrity level

Introduced by IEC-61508 standard, safety integrity levels (SIL) have been used for assessing the reliability of safety instrumented functions (SIF) for protection of the system under control in abnormal conditions. Different qualitative, semi-qualitative and quantitative methods have been proposed by the standard for establishing target safety integrity levels amongst which “Risk Graph” has gained wide attention due to its simplicity and easy-to-apply characteristics. However, this method is subject to many deficiencies that have forced industry men and experts to modify it to fit their demands. In this paper, a new modification to risk graph parameters has been proposed that adds more flexibility to them and reduces their subjective uncertainties but keeps the method as simple as before. Three parameters, namely severity (S), hazard avoidance probability (P), and demand rate (W) are used instead of former four parameters. Hence, the method is named SPW. The outcome results of this method can be directly converted to probability of failure on demand (PFD) or risk reduction factor (RRF). The proposed method has been tested on an example case that has been studied before with conventional risk graph and LOPA techniques. The results show that new method agrees well with LOPA and reduces costs imposed by conservative approximations assumed during application of conventional risk graph.     

煤矿安全隐患动态分级闭环管理方法及应用

为了治理煤矿生产过程中的安全隐患,遏制煤矿安全生产事故,对煤矿生产过程中的安全隐患管理进行了研究。经过梳理国内外相关文献,辨析了煤矿危险源和安全隐患的关系;结合脆弱性分析了煤矿安全隐患的风险大小,结合LEC法说明了安全隐患风险分级标准;结合煤矿生产过程的特点,提出了煤矿安全隐患动态分级闭环管理方法,设计了与之配套的奖惩办法。煤矿安全隐患动态分级闭环管理方法和配套的奖惩办法在南方的一个千万吨级矿井进行了应用。研究表明,该方法可以有效提高煤矿安全隐患的治理能力,提高煤矿现场的安全管理水平。     

电子封装行业化学有害因素职业暴露评价

以法规及风险评价模型为基础,对电子封装行业内通常使用的化学有害因素进行职业暴露分析,将健康风险进行分级、定量评价,得出结论:行业中回流焊工艺可能产生的铅烟、电镀车间存在的硝酸、失效分析中使用的氢氟酸等,其职业暴露风险为中等风险水平;但由于化学物质的健康危害等级HR因其固有性而相对不变,而其会随控制措施的效果高低而变化的暴露等级ER是一个可变的要素,不同企业的控制措施的水平高低不同,其最终的风险等级可能是不同的。行业中使用的氢氧化钾、氢氧化钠的职业暴露风险为低风险水平,前提也是在合理有效的控制措施环境下。因此,控制措施的水平就是决定风险等级的最重要因素。时时地运行和维护有效的控制措施,是确保风险水平不发生变化的关键。     

环境风险源及其分类方法研究

环境风险源的分类是进行环境风险源识别和监管的基础.已有的以人的安全为主要关注对象的重大危险源管理,对事故的潜在环境危害考虑欠缺,无法体现事故可能产生的环境风险影响.阐明环境风险源的基本概念,比较环境风险源与危险源的区别,针对环境风险源的特点,从环境受体、危害物质状态和风险传播方式3个方面提出了环境风险源的分类方法.实际应用中,环境风险源的分类需综合考虑当地环境管理需求、环境受体状况、主要危害物质类别等,选择合适的分类方法.     

Delphi法职业危害风险评估模型及案例研究

为科学合理地进行建设项目职业病危害风险分类,基于系统工程及风险评估的基本原理,采用Delphi法分析和确定了影响职业病危害风险程度的因素,通过构建风险评估指标体系,建立了职业病危害影响因子赋值法(OHFA)定量化风险评估模型。根据对作业场所的危害源、本质及附加防护设施水平、人员接触机会、职业病防治管理等因子的综合分析,预测分析了研究对象的职业病危害的风险程度,为职业病危害风险辨识、风险评估、防治管理及防护设施设计等提供参考。并以某石化行业硫磺回收项目为实例进行应用与验证,得出了该项目的总体职业病危害风险度值为12,风险等级为Ⅰ级,各职业病危害因素的风险度由高到底排序为硫化氢、一氧化碳、二氧化硫、硫磺、高温,其风险分类的关键决定因素为硫化氢。实践表明该方法与专家评估结果及工程实际吻合较好,应用于职业病危害风险评估中可给出定量化的风险分类结果。     

Evaluation of risk and cost using an age-dependent unavailability modelling of test and maintenance for standby components

The improvement of safety in the process industries is related to assessment and reduction of risk in a cost-effective manner. This paper addresses the trade-off between risk and cost related to standby safety systems. An age-dependent unavailability model that integrates the effects of the test and maintenance (T&M) activities as well as component ageing is developed and represents the basis for calculating risk. The repair “same-as-new” process is considered regarding the T&M activities. Costs are expressed as a function of the selected risk measure. The time-averaged function of the selected risk measure is obtained from probabilistic safety assessment, i.e. the fault tree analysis. This function is further extended with inclusion of additional parameters related to T&M activities as well as ageing parameters related to component ageing. In that sense, a new model of system unavailability, incorporating component ageing and T&M costs, is presented. The testing strategy is also addressed. Sequential and staggered testings are compared. The developed approach is applied on a standard safety system in nuclear power plant although the method is applicable to standby safety systems that are tested and maintained in other industries as well. The results show that the risk-informed surveillance requirements differ from existing ones in technical specifications, which are deterministically based. Moreover, the presented approach achieves a significant reduction in system unavailability over a relatively small increase of total T&M costs.