Situational awareness and safety

This paper considers the applicability of situation awareness concepts to safety in the control of complex systems. Much of the research to date has been conducted in aviation, which has obvious safety implications. It is argued that the concepts could be extended to other safety critical domains. The paper presents three theories of situational awareness: the three-level model, the interactive sub-systems approach, and the perceptual cycle. The difference between these theories is the extent to which they emphasise process or product as indicative of situational awareness. Some data from other studies are discussed to consider the negative effects of losing situational awareness, as this has serious safety implications. Finally, the application of situational awareness to system design, and training are presented.     

基于事故树的空中交通管制员情景意识分析

为更系统地研究管制员的情景意识,找出导致管制员情景意识丧失的主要因素,运用事故树分析法、采用自上而下的方式对管制员情景意识丧失的原因进行逐层分析,建立管制员情景意识丧失事故树模型。通过进一步计算事故树的最小割集和各基本事件的结构重要度,计算各基本事件的结构重要度系数,对比得出情景意识丧失的各个基本事件的重要程度及各事件之间的关系。结果表明,造成情景意识丧失事故的主要原因是轮班制度不合理、睡眠效率低及对特情不熟悉、飞行冲突预判能力弱。     

Human factors applied to alarm panel modernization of nuclear control room

Human factors deal with issues related to humans, their behavior and the physical aspect of the environment in which they work. A control room is a complex system where operators perform plant operation using control systems and carry out monitoring and administrative responsibilities. For safe operation of industrial installation, the performance of the control room crew plays an important role. In this respect, a well designed control room is crucial for safe and efficient operation. The aim of this paper is to propose a methodological framework applied to nuclear control room evaluation, through participatory ergonomics, using operator activity analysis and human factors questionnaire as aid tools. We describe a case study in which the methodology framework was used in the evaluation process of a nuclear control room. The information gathered made possible a series of recommendation for the adequacy of the control room design, assisting in the safety assessment of the nuclear plant operation and justifying the alarm panel modernization.     

Determination of human error probabilities for offshore platform musters

The focus of this work is on prediction of human error probabilities during the process of emergency musters on offshore oil and gas production platforms. Due to a lack of human error databases, and in particular human error data for offshore platform musters, an expert judgment technique, the Success Likelihood Index Methodology (SLIM), was adopted as a vehicle to predict human error probabilities. Three muster scenarios of varying severity (man overboard, gas release, and fire and explosion) were studied in detail. A panel of 24 judges active in the offshore oil and gas industry provided data for both the weighting and rating of six performance shaping factors. These data were subsequently processed by means of SLIM to calculate the probability of success for 18 muster actions ranging from point of muster initiator to the final actions in the temporary safe refuge (TSR). The six performance shaping factors considered in this work were stress, complexity, training, experience, event factors and atmospheric factors.     

Impact of training programs on decision-making and situation awareness of trainee watch officers

This paper examines the impact of training programs on the ability of trainee watch officers to make decisions in collision avoidance situations.It draws on previous studies which have shown that experts are able to manage complex situations in an acceptable way. However, observations of students on simulators have revealed that many of them are unable to manage such situations or even to recall their main features. It is therefore necessary to identify new training tools that will give trainees the capacity to assess a situation quickly and accurately, and to perform satisfactory actions. These would be in addition to formal regulations.Exercises were designed to evaluate the impact of such tools on the decision-making process of trainees. The impact of the type of navigation experienced by trainees during their on-the-job training was also evaluated.Results showed that decision-making exercises did tend to improve the trainees’ capacity to analyse a complex situation; however, they did not have a clear impact on the manoeuvre performed. On the contrary, there was an obvious difference between the trainees who experienced complex avoidance situations during their on-the-job training period and those who did not.At a time where ship-owners are looking to reduce the length of the “on-the-job” training period, these results point to its vital importance.     

氮肥企业重大危险源安全监控系统设计

安全监控系统是重大危险源企业预防和控制生产事故的重要技术措施.以氮肥厂为案例,分析了其运营过程中存在的主要危险因素和建立重大危险源安全监控系统的技术需求,在此基础上设计了重大危险源安全监控系统,建立了基于空间信息技术的重大危险源多模式安全监控平台.该平台可以通过网络联入城市或国家重大危险源安全监控系统,有利于政府和行业部门对重大危险源的监管.借助于这样的数字化动态管理系统,可以及时获得相关参数与信息,实现早期预警,降低重大危险源企业的事故风险.     

The role of situation awareness in accidents of large-scale technological systems

In the last two decades, several serious accidents at large-scale technological systems that have had grave consequences, such as that at Bhopal, have primarily been attributed to human error. However, further investigations have revealed that humans are not the primary cause of these accidents, but have inherited the problems and difficulties of working with complex systems created by engineers. The operators have to comprehend malfunctions in real time, respond quickly, and make rapid decisions to return operational units to normal conditions, but under these circumstances, the mental workload of operators rises sharply, and a mental workload that is too high increases the rate of error. Therefore, cognivitive human features such as situation awareness (SA)—one of the most important prerequisite for decision-making—should be considered and analyzed appropriately. This paper applys the SA Error Taxonomy methodology to analyze the role of SA in three different accidents: (1) A runaway chemical reaction at Institute, West Virginia killing two employees, injuring eight people, and requiring the evacuation of more than 40,000 residents adjacent to the facility, (2) The ignition of a vapor cloud at Bellwood, Illinois that killed one person, injured two employees, and caused significant business interruption, and (3) An explosion at Ontario, California injuring four workers and caused extensive damage to the facility. In addition, the paper presents certain requirements for cognitive operator support system development and operator training under abnormal situations to promote operators’ SA in the process industry.     

Changes in risk perception among North Sea offshore personnel in the period 1990 to 1994

A self-completion questionnaire survey was carried out among employees on offshore oil platforms in the Norwegian part of the North Sea in February 1990 and repeated in February 1994. A total of 915 employees on eight platforms (five oil companies) answered the questionnaire in 1990 and the response rate was 92%. In 1994, 1138 respondents on twelve platforms and nine companies filled in the questionnaire. The response rate was 87%. Significantly fewer of the personnel felt at risk in 1994 compared to 1990. Likewise, a greater percentage of the employees were satisfied with safety and contingency measures, and experienced job stress to a lesser extent in 1994 than they did in 1990.     

Application of human factors evaluation in engineering design and safe operation of dense phase ethylene treaters

Ethylene treaters are widely used in the petrochemical industry to remove impurities from ethylene feedstock imported from pipeline networks or storage caverns. The safety concerns of dense phase ethylene treaters due to the reactive and highly flammable nature of ethylene are well known and studied. Under certain conditions, ethylene may self-polymerize and decompose violently with heat release. Under other conditions, ethylene will auto-refrigerate, generating cold liquids that may cause potential brittle fracture hazards. Therefore, dense phase ethylene treaters present design challenges with the unique combination of high temperature decomposition and cold temperature brittle fracture hazards.Due to these safety concerns, it is important to select the appropriate engineering design options for dense phase ethylene treaters and the associated regeneration facilities. Totally automated treater regeneration systems add complexity and instrument maintenance requirements while manually operated systems rely heavily on operator training and procedures. Unfortunately, little or no information or design guidance is available from published research findings in the literature on the evaluation and risk assessment of current industrial design options and practices for dense phase ethylene treaters.This paper presents a systematic risk assessment method to evaluate the engineering design and safe operation options for dense phase ethylene treaters. The proposed risk assessment method integrates human factors task analysis into the traditional HAZOP, LOPA and fault tree analysis to allow evaluation of automated, manual and hybrid approaches with a goal of selecting and optimizing design options to ensure plant safety. This approach provides a realistic assessment of the operational risk and allows identification of fit-for-purpose risk reduction. Applying this systematic risk assessment approach, a simpler and more cost effective design solution can be justified, thereby avoiding the need for a high integrity protective system.     

驾校考场防雷安全设计探讨

随着驾校考试手段的变化,大量电子、通信设备应用于考场,其雷击风险越来越高。做好驾校考场的雷电综合防护工程对避免和减少雷电灾害损失具有重要作用。通过对邹平安星驾校科目二考场项目的防雷工程进行剖析,指出驾校雷电防护要点,就如何做好直击雷、雷电感应和雷击电磁脉冲防护设计进行了初步探讨。按照安全、经济、有效的原则,对邹平安星驾校科目二考场采用避雷线进行直击雷防护,并运用接地、分流、屏蔽、等电位连接、安装电涌保护器等措施进行雷电感应和雷击电磁脉冲防护。该工程经过5年夏季雷暴季节的考验,没有因雷击造成灾害损失。     

重大危险源事故风险排序研究

本文将风险管理领域中风险排序的概念引入重大危险源安全管理中，提出了基于事故情景发生概率和造成死亡人数的风险评估和排序模型，并给出了基于统计分析的事故发生概率、基于死亡半径的死亡人数的确定方法。对某开发区的20个重大危险源进行了风险评估和排序，结果表明提出的方法对重大危险源的事故风险产生了明显的细分作用。研究成果对有关政府部门或企业确定重大危险源重点监察和管理的优先序，优化资源配置，提高管理效率具有一定的指导意义。     

An empirically derived taxonomy of pilot violation behavior

Violations occur when pilots deliberately break safety rules; they are a serious and vexing problem in aviation. Study one engaged cluster analysis, multidimensional scaling and Pathfinder network analysis on an experimentally derived similarity matrix of violation causes to discover the structure of violation reasoning. Using the insights so gained, a classification was constructed based on actor intent with four categories:

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Improvement. The intention is to increase safety or production, a desire to do better.

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Malevolent. The intention is to cause harm or reduce production, a desire to do damage.

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Indolent. The intention is to increase operator ease, a desire for lethargy.

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Hedonic. The intention is to increase operator excitement, a desire for sensation.

Study two tested the taxonomy for reliability by having aviation experts assign categories to six accident reports. The taxonomy was found to have a free-marginal multirater kappa of 0.82, which is considered excellent.     

The role of people and human factors in performing process hazard analysis and layers of protection analysis

Process hazard analysis (PHA) and Layers of Protection Analysis (LOPA) studies address human failures in operating and maintaining processes and the human factors that influence them, amongst other types of failures. People perform PHA and LOPA studies and, therefore, such studies themselves are subject to various possible human failures. Much less attention has been paid to the human factors that influence the performance of PHA and LOPA studies than human factors that influence hazard scenarios. Human failures in the performance of PHA and LOPA studies should be of significant concern to practitioners as such studies are difficult and time-consuming activities that place significant demands on participants, which increases the chance that errors will be made. Human factors such as willingness to rely on the unsubstantiated opinions of others, groupthink, underestimation of the frequencies of low-probability, high-consequence events, and allowing a false sense of accomplishment to distract from implementing study results must be recognized and addressed.This paper identifies and discusses various human factor issues that can influence the quality of PHA and LOPA studies covering preparing for, conducting, recording, documenting, and following-up on studies. Guidelines are provided to help minimize the extent to which these human factor issues may impair study quality.     

Safety in shipping: the human element

INTRODUCTION: There are numerous diverse papers that have addressed issues within maritime safety; to date there has been no comprehensive review of this literature to aggregate the causal factors within accidents in shipping and surmise current knowledge. METHODS: This paper reviewed the literature on safety in three key areas: common themes of accidents, the influence of human error, and interventions to make shipping safer. The review included 20 studies of seafaring across the following areas: fatigue, stress, health, situation awareness, teamwork, decision-making, communication, automation, and safety culture. RESULTS: The review identifies the relative contributions of individual and organizational factors in shipping accidents, and also presents the methodological issues with previous research. CONCLUSIONS: The paper concludes that monitoring and modifying the human factors issues presented in this paper could contribute to maritime safety performance. IMPACT ON INDUSTRY: This review illustrates which human factors issues are prevalent in incidents therefore this gives shipping practitioners a focus for interventions.     

Optimizing the design of storage facilities through the application of ISD and QRA

Four strategies can be used to achieve safety in chemical processes: inherent, passive, active and procedural. However, the strategy that offers the best results is the inherent safety approach, especially if it is applied during the initial stages of a project. Inherently Safer Design (ISD) permanently eliminates or reduces hazards, and thus avoids or diminishes the consequences of incidents. ISD can be applied using four strategies: substitution, minimization, moderation and simplification. In this paper, we propose a methodology that combines ISD strategies with Quantitative Risk Assessment (QRA) to optimize the design of storage installations. As 17% of major accidents in the chemical industry occur during the storage process and cause significant losses, it is essential to improve safety in such installations. The proposed method applies QRA to estimate the risk associated with a specific design. The design can then be compared to others to determine which is inherently safer. The risk analysis may incorporate complex phenomena such as the domino effect and possible impacts on vulnerable material and human elements. The methodology was applied to the San Juanico tragedy that occurred in Mexico in 1984.     

Improving older driver knowledge and self-awareness through self-assessment: the driving decisions workbook

PURPOSE: This study aims to assess whether the Driving Decisions Workbook, a self-assessment instrument for older drivers, increased self-awareness and general knowledge. This study also assessed perceptions regarding its usefulness, particularly as a tool for facilitating discussions within families of older drivers. A secondary purpose of the study was to determine if problems identified by drivers in the workbook related to problems they had with actual driving. DESIGN AND METHODS: The Driving Decisions Workbook was administered along with a questionnaire and a road test. A convenience sample of 99 licensed drivers aged 65 and above was used. RESULTS: After completing the workbook, about three fourths of the participants reported being more aware of changes that could affect driving. Fourteen percent reported that they had discovered a change in themselves of which they had not been previously aware. All respondents found the workbook to be at least a little useful and thought the workbook could help facilitate family discussions. Workbook responses were positively correlated with overall road test scores. Significant correlations were also noted between the road test and a majority of workbook subsection responses. IMPLICATIONS: This study indicates that the workbook may be a useful first-tier assessment instrument and educational tool for the older driver. It may encourage an older driver to drive more safely and/or to seek clinical assessment, and help in facilitating discussions about driving within their families.     

Application of Prevention through Design for hearing loss in the mining industry

INTRODUCTION: Overexposure to noise remains a widespread and serious health hazard in the U.S. service providing and goods producing industries. Excessive noise can lead to poor verbal communication and reduce the ability to recognize warning signals. These dangerous work conditions can also cause stress and fatigue. Occupational hearing loss is a permanent illness, with no recovery currently possible. METHOD: National Institute for Occupational Safety and Health (NIOSH) has recognized Noise Induced Hearing Loss (NIHL) as one of the ten leading work-related diseases and injuries in the United States, and has emphasized its importance as one of the critical areas expressed in the National Occupational Research Agenda. RESULTS: One of the most serious noise problems in the goods producing industries is the operation of continuous mining machines during underground coal mining. In order to minimize occupational hearing loss, noise hazards are "designed out" early in the design process. NIOSH is leading a national initiative called Prevention through Design (PTD) to promote this concept. This paper describes the quiet-by-design approach of a noise control that reduced noise exposures of continuous mining machine operators by 3dB(A) using the four functional areas of PTD, namely Practice, Policy, Research, and Education.     

危险化学品重大危险源辨识中的问题与对策

危化品企业在根据《危险化学品重大危险源辨识》(GB18218-2009)进行重大危险源辨识的过程中,有四个问题较难解决或处理,即危化品水溶液临界量的确定、重大危险源辨识物质法定范围的确定、部分物质临界量设置不合理、如何确定危险物质的存在量.针对这四个问题提出了相应的对策:对危化品水溶液,其临界量的确定可依据水溶液的主要危害特性,对照《危险化学品重大危险源辨识》(GB18218-2009)中的表2进行确定;对不属于危险化学品,但又具有易燃、易爆、有毒特性的危险物品,如果其数量超过类似危化品的临界量,建议参照危化品重大危险源进行相应的安全管理;对于危险物质临界量的确定,建议按照危险源可能造成的事故危害后果或范围推算确定;对于危化品实际数量的确定,建议按照企业可能存在的最大量或设计量进行计算.     

Research on 10-year tendency of China coal mine accidents and the characteristics of human factors

The trend of China coal mine accidents in the latest 10 years was studied and the human factors in these accidents were analyzed by multi-dimensional statistic analysis. It shows that the number of major coal mine accidents and the death toll in the accidents were decreasing steadily, while sporadic death accidents still accounted for the largest percentage of deaths. Gas outburst accidents, gas explosion accidents and mine water accidents remained the major part of the whole story and subject to close attention. Among the causes of these accidents, human factors accounted for 94.09%, of which intentional violation, mismanagement and defective design accounted for 35.43%, 55.12%, 3.54% respectively. Improper operational and management practices in which the safety system, procedures and specifications were neglected or broken were still key roots of China coal mine accidents.