Expert opinions, fuzzy probabilities, and warnings: toward a mathematical method for evaluating warning “read and heed” effectiveness

In many situations, and particularly in legal matters, decisions may be based on whether some possibility is judged to be “more probable than not”, as for example, whether a warning, had it been present, would “more probably than not” have prevented an injury. The probability of a warning accomplishing its purpose of preventing injury can, in principle, be computed based on probability calculus. However, this paper proposes that: (1) such computations must use “fuzzy” probability statements which as a result produce a range of weighted possibilities for the final outcome and, moreover; (2) the critical statistic for determining whether the outcome is “more probable than not” is the median rather than the mean of the possible outcomes. This paper briefly outlines the mathematics for such computations and provides several examples. The paper basically treats fuzzy probabilities as standard “random variables” restricted to the range of [0,1].For brevity, this paper only treats the multiplication of two or more fuzzy probabilities. However, this is adequate for evaluation of a two stage “read and heed”, or of longer multiple step linear sequences and is indicative of the general approach. Treatment of the additive and general case will be found in later publications.     

Application of domino effect quantitative risk assessment to an extended industrial area

Escalation of primary accidental scenarios triggering a “domino effect” have caused extremely severe accidental events in the chemical and process industry. The identification of possible escalation events is required in the safety assessment of sites where relevant quantities of hazardous substances are stored or handled. In the European Union, “Seveso-II” Directive requires the assessment of on-site and off-site possible escalation scenarios in sites falling under the obligations of the Directive. In the present study, a methodology developed for the quantitative assessment of risk due to domino effect was applied to the analysis of an extended industrial area. Recently developed equipment damage probability models were applied for the identification of the final scenarios and for escalation probability assessment. The domino package of the Aripar-GIS software was used for risk recomposition. The results evidence that quantitative risk assessment of escalation hazard is of fundamental importance in order to identify critical equipment and to address prevention and protection actions.     

The reality of “Revitalizing Health and Safety”

Problem: Workplace health and safety remains an important international socioeconomic issue, but the progressive declines in reported incidents may be slowing. The British Government has responded by launching a new policy initiative aimed at “Revitalizing Health and Safety” by establishing targets for improvement, strategies, and a series of action points, mainly targeting employers and organizational issues. This paper critically assesses the realities of implementing this policy with respect to the scientific base for each of the strategies. Method: Literature meta-analysis; analysis of policy. Results: Empirically proven determinants of workplace health and safety provide baselines for compensation and conditions of work, workforce characteristics, workplace characteristics, health and safety environment, political and economic factors, and industry characteristics. Support for different policy elements is varied and there are some significant gaps. Summary: An impressive body of research was found that offers a firm foundation for future developments. However, the need for work that is interdisciplinary, ordered, and collaborative is pressing. The need to move away from elegant but simplistic pictures of occupational health and safety (OHS) management practice, and to reflect true complexity is imperative. The reality of health and safety at work is that it is an issue that is taken lightly by those who do not practice or research safe and healthy working, and a serious issue for victims or relatives of victims of shoddy management. It remains one of the bastions of inequality of work worldwide. Impact on industry: The intent of governments in attempting to reinvigorate the suppression of workplace injury and illness is motivated by both social and economic imperatives. Motivation for organizations is not fully understood as there is no obvious business imperative. If organizations can further understand and provide a scientific justification for investment in OHS management, then governments' task will be made easier. By proving the value of OHS to management, we will demonstrate that organizations continue to present considerable hazards to their employees.     

A risk-estimation methodological framework using quantitative assessment techniques and real accidents’ data: Application in an aluminum extrusion industry

The risk estimation presumably is the most crucial part of the entire procedure of assessing hazards/unsafe situations in the work, and especially in the industries’ and constructions’ worksites, where the working conditions are unstable. We can consider the risk as a quantity, which can be estimated and expressed by a mathematical relation, under the help of real accidents’ data. The aim of this work is quadruplicate: (a) the development, elaboration and explanation of two new quantitative risk-assessment techniques, (b) the improvement of specific points of other scientific works, as far as concerns quantitative risk estimation, (c) the application of these techniques on an industrial productive procedure (as a case study) and (d) the comparison of their outcome risk-estimation results. Particularly, we develop and analyze the theoretical background of the two techniques, which we call as “proportional technique” and “decision matrix technique”, and apply them on an aluminum extrusion industry's worksite, which is situated in Greece, by using real data of potential sources of hazards, recorded by safety managers, during the 5.5-year time period of 1999–2004. Comparing the results of the two quantitative risk-assessment techniques, we infer that they are compatible. Therefore, the most important hazard source in the aluminum industry is the “squeezing and hits by dropping objects (transported by derricks)”, and imposes that immediate suppressive measures must be taken place to abolish the danger source.     

“Vybuchovy trojuhelnik”: A software tool for evaluation of explosibility of coal mine atmosphere

Rescue operations during mine fires or methane explosions are highly dangerous for rescue workers. The knowledge of the composition of the coal mine atmosphere and the calculations of its explosibility may help to increase the safety of the rescuers. In the Czech Republic, a system called “Mine Gas Laboratory” (DPL) has been used for these purposes. The DPL allows measurement of the composition of the mine atmosphere and transmits the data necessary for evaluation to the surface. Up to now the explosibility evaluation of the coal mine atmosphere has depended either on the rescuers’ experience or on software code calculation. The code called “Vybuchovy trojuhelnik” (explosion triangle) is a graphical computing system intended for fast assessment of explosibility of fuel–air mixture. This article introduces the code and describes two simple methods of explosibility evaluation. The first method is “explosion triangle analysis”—a graphical method based on empirical graphs transformed into equations. The second method uses thermodynamic calculation based on chemical balance dynamics and Gibbs and Helmholtz energy. According to the requirements of the Czech Bureau of Mining (CBU) and Central Mine Rescue Service (HBZS), the code solves the problems of explosion triangle for both standard and non-standard coal mine atmosphere compositions. Unfortunately, the atmosphere composition must be introduced manually due to the unknown format of the data transmitted from the old DPL model. On 1 September 2005, a project started to develop a new system for on-line monitoring and atmosphere explosibility evaluation. The system should be able to measure CO₂, O₂, CH₄, H₂ and CO concentrations as well as the wind speed, temperature and humidity. The “Vybuchovy trojuhelnik” code will be used as a basis for explosibility evaluation, and an on-line connection with the new model of DPL will be established.     

Risk and system integrity concepts for safety-related control systems

This paper provides an overview of the concepts of “risk” and “safety-integrity” in relation to safety-related electrical/electronic/programmable electronic systems. The paper is an abridged version of Annex A of the emerging International Electrotechnical Commission (IEC) Standard; “Functional safety of electrical/electronic/programmable electronic systems”. Although based on Annex A, the authors have deviated in a few instances, from the strict wording of Annex A in order to more properly represent their own views. Where this occurs, a note in the text has been added to alert the reader of the deviation. The concepts of risk (including tolerable risk; safety integrity; safety-related system; System and Software Integrity Levels) are discussed.     

Intrinsic road safety: A new approach?

In 1991 the Dutch Ministry of Transport, Public Works and Water Management concluded that its policy regarding road-safety should be sharpened in order that its goal set for road-safety in the year 2010 would be achieved (i.e. 50% reduction of dead and 40% reduction of wounded persons in comparison with 1986). This new policy is being called “Intrinsic Safety”.The important elements of this course of action are:

• - A greater degree of control of structural developments.

• - Increased action to prevent accidents rather than that which reduces the severity of the consequences of accidents.

• - Greater attention for an integral approach of traffic safety, through influencing all kinds of decision makers outside the realm of traffic safety.

• - Not viewing and treating the human aspects, the roads and the vehicles in isolation, but primarily focusing attention on the interaction between these components.

At the moment the Ministry has inaugurated some actions which will be a more specific elaboration of “Intrinsic Safety”.In this paper we will try to analyze whether this new policy is a totally new concept rather than an intensification of the old course of action. Furthermore we will discuss a few problems which may occur when the “Intrinsic Safety” approach will be elaborated in the near future. For example:

• - How do we make sure that chosen measures (e.g. decisions concerning the infrastructure) will be the most effectual ones in relation with safety?

• - Is the organisation at this moment sufficiently fit to work on an “intrinsically safe traffic system” or is it inappropriate? (e.g., presently there is an increasing tendency of decisions being made by regional departments rather than by central government)

• - Are we in the possession of sufficient knowledge concerning the interactions between the several goals of traffic policy so that actions taken in relation with one goal (e.g. reducing air pollution) will not have a negative effect on traffic safety?

     

Fire risk management system for safe operation of large atmospheric storage tanks

This paper has been prepared by its authors to show the benefits coming from the application of the fire risk assessment methodology prepared by the “LastFire^© Project” group of experts. Now a days this methodology seems to be very effective to face the fire risk connected with large atmospheric storage tanks. It has been developed during the period 1997–2005 the HSE & operations experts from experts 16 worldwide operating oil companies. The authors, by “ad hoc” created software package, show the benefit coming from the applications of the LastFire^© methodology and how, from this, using the methodology and the supporting tad, realize a coherent fire strategy in the form of a Fire Risk Management System. Same workflow could also be extended to the issues connected with other problems related with large atmospheric tanks storing hydrocarbons, such as environmental impact by soil pollution, to create a common frame walk of assessment not can be shared with authorities as well. The proposed methodology, moving from the original project, sets as an effective “Fire Hazard Management Approach” in line with the most recent trends (even enforced by the regulations) shared at international levels, that propose the integration of risk assessment with prevention and protection measures selection based on achieved risk reduction, costs, time needed, etc.     

A learning-by-doing strategy to improve top management involvement in safety

The growth of legal regulations in occupational safety during the 70's alienated to some extent top management from health and safety issues; safety was regarded as an activity of safety professionals and labour inspection. This lack of commitment to safety management led to reduced activity and awareness. However, both research and practice indicate that the role of top management is of crucial importance for achieving results in safety.Having realized the problem and the lack of appropriate training to meet the demands of top management, a program called “One hour for safety management” has been developed. The training is arranged in an “action” setting, during the formal meeting of the executive board of the company. The program consists of four main parts: (1) Principles of modern safety management, (2) The company's accident insurance system, the interdependency between compensation costs and premiums, (3) The safety situation of the company; accidents, premiums and losses, hazards, safety program, and (4) Setting the safety targets and action plans required. More recently, a short audit process has been developed to reveal the important sources of loss and the state of affairs in the company's loss control systems. A special software package includes essential handouts of the safety management meetings complemented by self-auditing tools.The approach initiated or revived top management interest in and awareness of safety in several companies. The success of the meeting seems to depend on several factors, e.g. consultation skills, safety expertise, style of presentation, corporate culture and co-operation in the preparation of the session. The factors that contribute to an effective training for top management should further be analyzed, and the impact of the management training on accident rates is a task for evaluation studies in future.     

道化学评价法的改进及其在联合站安全评价中的应用

道化学评价法是一种在化学工业领域应用广泛的安全评价方法,针对道化学评价法评价未考虑人员、环境及设备维护等因素而使评价结果不够准确的情况,提出了在安全补偿系数选取中引入物质系数修正、人因危险补偿系数、环境补偿系数和设备状态补偿系数对道化学法进行改进。首先通过对物质燃烧性进行温度修正获取实际情况下的物质系数值,同时通过统计数据分析计算出人因行为概率,进而计算人因危险补偿系数,此外结合设备可靠度引入了设备状态补偿系数。将以上改进方法应用到某油田联合站原油稳定装置和轻烃储罐装置的安全评价中,结果表明经过改进的道化学评价法能更客观地反映实际情况,评价结果更准确,同时根据改进后得到的危险等级提出了稳定装置及轻烃储罐装置安全运行的对策措施,最后结合事故案例对比了传统道化学和改进道化学的结果,说明了改进方法的准确性和优势。     

Personal protectors and working behaviour of loggers

Safety measures have not always been as effective as anticipated. If workers change their behaviour, e.g. by taking more risks, the benefit of the safety improvement is lost. This phenomenon is called risk compensation. There is some indirect evidence for and against risk compensation among Finnish loggers as regards the use of personal protectors. Two studies suggest that the accident rate would have risen 3–5.5-fold if all the cases prevented by the protectors had been injurious. In Study 1 (n = 1200) the use of personal protectors did not reduce accident injuries. In Study 2 (n = 225), 90% of the test persons had noted that the use of personal protectors enhances the feeling of safety. Nearly half of the loggers reported that their work behaviour changed when they wore personal protectors; they became more careless, faster, bolder, and they anticipated less dangers. In Study 2, the use of protectors reduced accident injuries. This finding does not support the hypothesis of complete behavioural adaptation. The conclusion drawn on the basis of these two studies is that the change in behaviour when using protectors does not entirely nullify the protecting effect of protectors, so that the compensation could rather be partial.     

催化裂解装置火灾爆炸危险性评价

道氏方法是对石化装置风险性进行量化评价的一种行之有效的方法,尤其是对装置的系统和单元的固有危险性及安全设施降低危险性的安全补偿作用进行认识和评价,采用道化学公司的火灾、爆炸危险指数法,对安庆石化炼油厂65×104t/a催化裂解装置的潜在火灾爆炸和反应危险性进行评价和分析,得到“严重”以上程度的单元有:加热炉、丙烷塔、丙烯塔、液化气储罐和汽油柴油储罐、反应器、瓦斯发生器、乙烷塔和稳定器,同时给出单元的危险等级和薄弱环节,为工厂的风险管理和安全管理决策提供了科学依据,并为降低装置风险提出了建议。     

“Slippery” work surfaces: Towards a performance definition and quantitative coefficient of friction criteria

There have been 50 years of research in walking/working surface slipperiness and coefficient of friction (COF) measurements. Nevertheless, numerous standards address slip/fall accidents only in terms of requiring surfaces to be qualitatively “nonslippery.” The literature useful for establishing quantitative criteria for “slippery” vs. “slip-resistant” have been summarized here. A performance definition for “slippery work surfaces” is proposed. Recommendations applicable to standards-making organizations are made, including changing terms such as “non-slip” to “slip-resistant” and defining “slippery” in terms of quantitative COF values. For persons walking unloaded on level surfaces, a COF standard of 0.5 would be reasonable. Research is recommended to determine if “slip-resistance” requirements and accident prevention could be achieved more easily be controlling the type of shoe, type of task, or amount of surface contaminant rather than controlling only the COF of the basic surface and its coating.     

The effect of aviation safety education on passenger cabin safety awareness

This paper examines the effect of aviation safety education on passenger cabin safety awareness in knowledge, attitude, and behavior (KAB). The educational value of KAB has been addressed in various fields such as AIDS prevention and campus safety. KAB has been applied in aviation safety related areas, especially in training, such as crew resource management training, pilot training, and mechanic training. However, KAB has not been implemented in aviation passenger education in cabin safety. This paper uses the construct of “aviation safety education”, which is intended to influence airline passenger knowledge of, attitude toward, and behavior about cabin safety awareness. Passenger surveys were done at two Taiwan airports. The results show that aviation safety education positively affects airline passenger cabin safety knowledge, attitude, and behavior. We recommend safety education that involves accurate instruction about emergency equipment procedures, situational awareness, emergency responses, and relevant cabin-safety regulations.Our findings indicated that an increase in cabin safety knowledge positively affected airline passenger behavior, which supported knowledge–behavior consistency. We also found that a positive attitude toward cabin safety positively affected airline passenger behavior, which supported attitude–behavior consistency. The hypothesis that cabin safety knowledge positively affected passenger attitude – knowledge–attitude consistency was not supported.     

有毒化学品泄漏事故应急防护行动决策探讨

当发生有毒化学品泄漏事故时,为保护公众和工人的安全和健康,需要快速地选择合适的应急防护行动.通常采用的应急防护行动有疏散、隐蔽、使用个人防护装备和服用解毒剂等.决策者必须权衡大量影响因素间的相互作用,如化学品的释放特征、事故现场的气象条件及影响范围内的人群分布等来进行应急防护行动决策.本文在分析应急防护行动决策过程关键要素的基础上,详细总结了影响应急防护行动决策的因素,介绍了应急决策常用的方法,以便在有毒化学品泄漏事故的应急过程中有效决策,最大限度地减少人员伤亡.     

The effect of habit as a behavioural response in risk reduction programmes

A company's decision to implement a risk reduction programme must take account of employees' behavioural responses to the target risk. Hazard reporting by train drivers is examined in semi-structured interviews and a questionnaire study. It is suggested that the behavioural response of drivers, in terms of writing a report, depends on how the hazard is perceived. The response to “trivial” and “routine” hazards is habitual non-reporting, being characterized by a lack of risk evaluation. However, hazards that are evaluated as posing a significant risk are reported. Possible ways of breaking habitual responses to hazards, using behavioural change programmes, are discussed, and it is argued that management commitment is essential for their success.     

Occupational health and safety promotion: Problems and solutions

Most occupational safety and health (OSH) professionals would agree that having a good OSH promotion programme is a challenge, and problems can be encountered at almost every stage in the planning and delivery of the programme.The first obstacle which may be encountered is programme justification. How does one convince employers and employees of the need for OSH promotion, and does competition from “Wellness Programmes” reduce available resources? Programme planning, deciding what constitutes a programme, and what to include in the OSH promotion programme, may be a dilemma. The programme implementation, deciding who implements the activities and how a programme is sustained, may be other difficult issues. Finally, programme evaluation can be problematic: How is it done properly? and Who should evaluate the programme?Possible solutions to these problems may include the costing of work accidents and occupational ill health to justify the need and benefits of an OSH programme, and riding on the bandwagon of “wellness promotion” instead of competition for limited resources. In programme planning, knowing what is wanted and employing a professional to plan the programme is essential. The programme coverage should encompass health and safety issues, and preventive strategies should be directed towards both environment and lifestyle factors. There should be a prioritization of topics according to the needs of workers. The choice of OSH professionals versus “wellness promoters” or human resource officers as programme co-ordinators may affect the programme outcome. Training supervisors and line workers to be trainers would involve those directly in contact with work hazards in the programme. Programme evaluation is crucial. There should be provision for both process and outcome evaluations, and pains should be taken to ensure independence and objectivity of evaluations. The idea of linking programme results to the OSH personnel assessments is worth considering.The delivery of OSH promotion programmes in a relevant and effective manner poses a real challenge. While some obstacles and problems appear to be insurmountable, these challenges have to be faced and overcome in order to achieve the goals of protecting and promoting the health of the worker.     

建筑施工高处吊篮作业安全防护预警模型研究

为提升高处吊篮作业的安全防护水平,为建筑施工安全防护预警模型研究提供理论支持,针对安全防护不足和缺位对高处吊篮作业的不利影响,建立高处吊篮作业安全防护预警指标体系。通过对作业人员的筛选,作业信息采集及数据化处理,构建基于SVM（支持向量机）的高处吊篮作业安全防护预警模型。最后,通过对历史样本数据仿真模拟验证模型的适用性和可行性。研究结果表明:建筑施工高处吊篮作业安全防护预警模型的仿真模拟结果与实际结果相比较为吻合,从安全防护审批、个体防护用品、安全防护设施、安全防护标识、心理生理防护及作业条件防护6个方面进行分析构建的安全防护预警模型可为高处吊篮作业提供预警支持,并可作为建筑企业安全管理系统的一部分,推广至其他特种作业领域。     

Some unusual case histories from personal experience

Is protection of equipment the only consideration when setting the relieving pressures of safety relief valves? I will show you a case where other factors should have been considered and suggest that you might give your safety valve set pressures a second thought.Do you have side-by-side pieces of identical equipment? If so, you must consider that operating or maintenance personnel may become confused, and the results maybe catastrophic. A PVC reactor incident will demonstrate this point.Does your process contain materials that could decompose? After thirty years of safe operation in butadiene units, there was a vinyl acetylene decomposition. Could it happen to you?It is my hope that these three unique and unusual cases will provide valuable information for operations and maintenance personnel, managers, safety professionals, and engineers.     

What is most important for safety climate: The company belonging or the local working environment? – A study from the Norwegian offshore industry

Obtaining knowledge about factors affecting health, safety and environment (HSE) is of major interest to the petroleum industry, but there is currently a severe shortage of relevant studies. The aim of this study was to examine the relative influence of offshore installation (local working environment) and company belonging on employees’ opinions concerning occupational health and safety. We analyzed data from a safety climate survey answered by 4479 Norwegian offshore petroleum employees in 2005 on the dimensions “Safety prioritisation”, “Safety management and involvement”, “Safety versus production”, “Individual motivation”, “System comprehension” and “Competence” using one way analysis of variance (ANOVA), effect size and mixed model. The companies differed significantly for “Safety prioritisation”, “Safety versus production”, “Individual motivation”, “System comprehension” and “Competence”. The local offshore installation explained more of the safety climate than the company they were employed in or worked for did.