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.     

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.     

Eye movement and reaction time measures of the effectiveness of caution signs

The effectiveness of various forms of caution signs was evaluated using saccadic eye movements and reaction time as the dependent variables. Both dependent measures show that caution signs requiring specific positive actions are processed more slowly and less efficiently than signs requiring avoidance behaviors. Additionally, the data show that changing the order of the “consequences” and “instructions” elements of the caution signs did not influence the number of saccades, the speed, or accuracy of interpretation. The research shows that saccadic eye movement may be an effective method for evaluating the design of caution signs.     

Improving the effectiveness of warnings by increasing the appropriateness of their information content: some hypotheses about human compliance

The ways that warnings are administered vary greatly. A warning may come as a message broadcast on the radio about severe weather, as a flashing light in the cockpit of an airplane, or as an audible smoke alarm. Typically, warnings provide an auditory or visual signal to assist in the detection of an anticipated stimulus. However, warnings tend to operate in an all or none mode: either the warning is present, or it is not. Consequently, the information they provide is limited. If warnings are provided too often, their information content becomes even lower and frequent false alarms render them ineffective because of the “cry-wolf” effect. On the other hand, if warnings are not administered frequently enough, they result in too many potentially costly misses. In this conceptual paper, it is argued that the effectiveness of warnings might be significantly improved if warnings are made more “intelligent” by providing information about the likelihood of the occurrence of the stimulus. Several representative cases are discussed and analyzed in order to demonstrate the advantages of the proposed methods.     

Measurement techniques for organizational safety causal models: Characterization and suggestions for enhancements

Through a review of literature from diverse disciplines with actual and potential application to causal modeling of organizational safety risk, this paper explores issues regarding measurement techniques in a quantitative safety analysis context. The interdependencies of modeling perspectives, constructs, and measures are indentified, leading to (a) characterization and classification of measurement techniques, (b) suggestions on the selection of appropriate measurement methods for different types of model constructs including individual-level, global, configural, and shared, and (c) discussion of the modeling implications of interactions between measurement, constructs, and causal paths. A multi-dimensional perspective is offered through combinations of different “measurement methods” and “measurement bases”. A Bayesian approach is also proposed to operationalize the multi-dimensional measurements. Examples are provided to help explain the roles of these measurements in capturing the relation between organizational factors and safety performance. This paper is a product of research which has the primary purpose of extending Probabilistic Risk Assessment (PRA) modeling frameworks to include the effects of organizational factors as the fundamental causes of accidents and incidents.     

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.     

特种劳动防护用品生产企业基本情况统计分析

国家于2006年开始对21种特种劳动防护用品实行安全标志管理,到目前为止,已有786家特种劳动防护用品生产企业获得了安全标志许可证书。本文通过对786家获得安全标志许可证书的特种劳动防护用品生产企业的数量、分布、注册资金、人数以及产品种类等相关数据进行统计,分析了当前我国的劳动防护用品生产企业整体现状,即还处于水平较低、实力较弱的状态,并提出了加强劳动防护用品生产企业力量的措施和建议,包括降低劳动防护用品生产企业税负,发放低息贷款,加强科研经费的投入等。     

Early impacts of alcoholic beverage warning labels: national study findings relevant to drinking and driving behavior

After November, 1989 Federal law required a standard health warning label on all alcoholic beverage containers sold for consumption in the U.S. Results are reported from a cross-sectional national household telephone interview survey of adults, occurring approximately 6 months after implementation of the warning labels (N=2000). Implications for health warnings with respect to information processing theory, the Health Belief Model, and other theories relevant to precaution adoption are briefly reviewed and two derivative hypotheses are tested using log-linear analysis. Relationships between various personal characteristics and (a) seeing the label and (b) recalling the driving impairment message are examined for consistency with theoretical expectations. We also examine associations between message recall, drinking style, and two precautionary behaviors undertaken to avoid drinking and driving. Adjusting for apparent false positives, approximately a quarter of the sample have noticed the label 6 months after its introduction; 16% recalled the specific driving impairment message. As hypothesized, exposure to the warning was predicted primarily by consumption pattern but also was associated with a personal salience factor, that is, ever having drunk alcohol so as to be at risk when driving. About a quarter of the heavy drinkers (5 drinks or more per occasion sometime and drinking at least weekly) who ever drank and drove saw the specific warning. Of two self-regulation strategies — limiting driving after drinking and limiting drinking when about to drive — the latter was the more prevalent. Both strategies were reported more by those who were heavy drinkers, those recalling the driving impairment message, and those perceiving driving after drinking to be very dangerous, than by other individuals.     

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.     

Integrating human factors and systems engineering to reduce the risk of operator “error”

Introducing safety devices does not always reduce the frequency of accidents. Operators adjust their response to technological improvements. Protection mechanisms may be used to support “unsafe” working practices so that the net risk of failure remains unchanged or may even rise. Regulatory bodies have reacted against this risk compensation. Rules and procedures have been imposed upon the day-to-day operation of protection equipment. Unfortunately, these constraints often fail to preserve the safety of an application. Inattention, fatigue, poor training and willful neglect can lead to rules and guidelines being ignored. In this paper alternative means of reducing threats posed by risk compensation are explored. In particular, it is argued that designers must exploit an integrated approach to the development of high-risk applications. By this we mean that both human factors and systems engineering must be recruited to support the development of protection equipment.     

欧美、日本与中国个体防护标准比对

个体防护装备,以往称劳动防护用品,是以保护劳动者安全和健康为目的,并且直接与人体接触的装备或者用品。从某种意义上讲,它是保障劳动者安全和健康的最后一道防线,在保护劳动者和确保安全生产方面有着重要意义。经过多年努力,我国在个体防护装备的技术标准方面制定并颁布了一系列国家标准和行业标准,并形成了初步的标准体系,本文研究了ISO、CEN、JIS的个体防护标准体系,并着重对其体系和有代表性的标准进行比对分析,从而归纳出我国个体防护及检测技术标准存在的问题,对制定和提高我国个体防护装备的体系建设具有一定的参考意义,并为个体防护及检测领域的相关国际标准的研制工作提出一些建议。     

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.     

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.     

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.     

Filterability of oil sands tailings

In Canadian oil sands mining operations, bitumen is extracted from oil sands using the hot water extraction process, which produces tremendous amounts of tailings. Currently, these tailings are disposed of in large ponds, in which coarse particles settle out relatively quickly and fine particles remain suspended in water and settle very slowly. After years of settling, the fine particles form a stable suspension in water known as mature fine tailings (MFTs). Long-term storage of the MFT is costly and poses a major environmental liability.Oil sands companies are now actively investigating different approaches to replace or reduce the use of oil sands tailings ponds. Filtration of the tailings to produce “dry tailings” for stacking is now being investigated as an alternative by a number of companies. Fast water drainage is a critical step for the filtration process. In this paper, we use simple laboratory-scale filtration tests to evaluate the filterability of the oil sands tailings and to generate a parameter that can be used in filtration scale-up. It was found that the filterability of the original coarse oil sands tailings was relatively low. However, after the fines are flocculated with the coarse particles to form uniform flocs the filterability was improved by several orders of magnitude. The results demonstrate that filtration of the flocculated coarse tailings to produce the “dry” stackable tailings may be viable.     

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.     

Strategies for controlling hazards at work

This paper presents an heuristic framework for analyzing hazards (potential for loss or harm) and strategies that may be developed to control their realization. Two basic forms of intervention for hazard control (anticipation and reaction) are identified. Three broad anticipative strategies are discussed: (1) elimination of the source of the hazard, (2) containment of the risk of its realization, and (3) mitigation of likely consequences. The communication and judgmental processes involved in decisions about strategies are shown to be embedded in the organizational “political” context, in which a variety of interests backed by varying sources of power and influence are represented. The development, implementation, and monitoring of any strategies that are decided upon are then discussed, including the fact that such actions and events may not produce the intended results. Comments are also made on the need for data provided by monitoring to be evaluated and appropriate adaptations made. Finally, a brief section of the paper discusses reactive strategies.     

Unified correlations for vent sizing of enclosures at atmospheric and elevated pressures

Innovative vent sizing technology is presented for explosion safety design of equipment at atmospheric and elevated initial pressures. Unified correlations for vent sizing are suggested. They are modifications of previously reported correlations verified thoroughly for experimental data on vented gaseous deflagrations under different conditions but only at initial atmospheric pressure. Suggested correlations are based on experimental data on vented deflagrations of quiescent and turbulent propane–air mixtures at initial pressures up to 0.7 MPa. Typical values of turbulence factor and deflagration–outflow interaction number are obtained for experimental vented deflagrations at initial pressures higher than atmospheric.

“Blind” examination of new vent sizing technology on another set of experiments with methane–air and propane–air mixtures has shown that predictions by suggested vent sizing technology are better than by the NFPA 68 guide for “Venting of Deflagrations”.

In the development of recently reported results for initial atmospheric pressure it has been concluded that the innovative vent sizing technology is more reliable compared to the NFPA 68 guide at elevated initial pressures as well. Moreover it is crucial that the calculation procedure remains the same for arbitrary deflagration conditions.     

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.     

天平的不等臂性对测试的影响

天平是一种重要的试验室检测仪器,在个体防护用品的检验工作中同样不可或缺,比如防护服的透气量测试、旋转辊筒法对防护鞋外底磨耗量的检测等,都会用到天平。本文主要从产生天平不等臂的原因及不等臂的检测、不等臂的调整等方面,简要论述了天平的正确性对测量的影响。