Expert Judgment within the Framework of Risk Assessment of Industrial Processes

Transcription

1 Expert Judgment within the Framework of Risk Assessment of Industrial Processes KATARINA KAMPOVA Faculty of Special Engineering University of Zilina Ul. 1.maja 32, Zilina SLOVAKIA Abstract: Contemporary society wants to create optimal conditions for the lives of their citizens and to ensure sustainable development. It is not possible to achieve this objective without reaching the required level of perceived security in global. One of the fields which threaten the lives and property of citizens and damage the environment is anthropogenic crisis phenomena which also include industrial accidents. Preventing their occurrence and consequent reaction are the key issues in adjusting the level of the security not only for the citizens in Slovakia and the EU but also worldwide. Faculty of Special Engineering at the University of Zilina addresses partial issues in the area of prevention of major industrial accidents which are necessary to be solved. Currently, this issue is solved within the project APVV Complex Model of Risk Assessment of Industrial Processes (MOPORI). This paper deals with the problem of expert judgment within the process of risk assessment solved within the framework of the mentioned project. Key-Words: major industrial accidents, prevention, SEVESO directive, risk assessment, expert judgement 1 Foundations and Results of the Project MOPORI The Slovak Republic as a member of the EU also solves the problem of the major industrial accidents prevention. The basic legal document which transposes directive SEVESO II into our legal environment is Act No.261/2002 Coll. Of Laws - law on the prevention of major industrial accidents, as amended, and other two implementing decrees [1]. There are several problematic areas in this field. In 2008, the EU Vri (The European Virtual Institute for Integrated Risk Management) made a questionnaire study, the purpose of which was to obtain information about the transposition requirements of the directive SEVESO II in all the member states. At the same time, it obtained information about and its general advance, practical experience with the use of weaknesses and problems associated with its practical implementation, efficiency of its implementations and its impact on the competitiveness of European industry. Consequently, the member states were asked to react by improving the form of this directive. The results of this survey supported the tendencies to create the above-mentioned new directive SEVESO III. The results of the survey are as follows [2]: In some areas, the respondents themselves see the opportunity to elaborate further supporting documents, whereby the point with the highest priority is the area of risk assessment and management. The area of concern is non-universality of the risk assessment approach, lack of the criteria to quantify the risks and the methods, tools and data used for implementation of the procedures. Many companies elaborate qualitative rather than quantitative analysis, which can conceal a higher level of uncertainty of the results. An approach to the risk assessment should be synchronized in accordance with the Directive SEVESO II on one hand and the legal norms in the field at particular country on the other. Selected findings from the survey indicate insufficient or formal approaches to the risk management within selected enterprises, and thereby confirm the possibility of elimination of the ISBN:

2 deficiencies by correct, system and mainly live approach of the subjects to the risk assessment and management. As results from the mentioned research, one of the most problematic areas in the sector of the prevention of the major industrial accidents is to assess and manage risks. This issue is not appreciated by the laic general public as well as by the expert public at the time when there is no accident in a long-term. However, in case it occurs, the loss of human lives and material values prove to everyone that the issues related to the prevention of this type of accidents are necessary. It is also necessary to address number of demands related to dysfunction of the risk management system in a given subject. These dysfunctions could occur either due to poor coordination of particular activities within the prevention or by inappropriate reaction to the resulting accident. The causes of these types of accident are various and in most of the cases it is possible to talk about formally elaborated system of risk assessment and management. It means that the complex interconnection is not secured considering the system, organizational, personal, technical or material aspects. It is just this crucial topic of assessment and management of risks which is the main problem being solved within the project APVV Complex model of risk assessment of industrial processes [1]. Project with the title Complex Model of Risk Assessment of Industrial Processes (thereinafter MOPORI) originated due to the requirements to create a simple and system approach to risk assessment and management. The main objective of the project is to increase a security level of industrial enterprises SEVESO establishments in the Slovak Republic by creating a complex model of risk assessment of industrial processes with the use of quantitative methods and by its synchronization with the standards of the EU and their subsequent application in Slovakian conditions. Duration of the project MOPORI is in the time interval 5/2011 4/2014. Throughout its duration, the project was given the main objective is to increase the level of the industrial security of the SEVESO establishments in Slovakia in accordance with the standards of the EU. The partial objectives that serve to meet the main objective have been set as follows: Setting of input and output parameters of the model on the ground of the current state analysis. Development of a complex model of the risk assessment of industrial processes based on new scientific approaches in the process of risk management, useful in the prevention of major industrial accidents. Integration and synchronization of the European standards in the field of major industrial accident prevention into established complex model of risk assessment of industrial processes in Slovakia. Verification of the proposed model based on the practical application in the SEVESO establishments and the subsequent correction of its deficiencies. Elaboration of a software tool to asses risks in the industrial processes. Accomplishment of the main declared objective of the project MOPORI is ensured by creating eight work packages, which are designed in accordance with the general project and implementing phases of the project management. The titles of the work packages are listed below: PB0 Management of the project PB1 Complex analysis of the current state of the problem solved PB2 Development of a complex model of the risk assessment of industrial processes PB3 Application of the European standards in the field of major industrial accident prevention into the complex model of the risk assessment of industrial processes in Slovakian conditions PB4 Verification of the complex model of the risk assessment of industrial processes in practice PB5 Elaboration of a software tool to assess the risks of the industrial processes in Slovakian conditions PB6 Popularization of the project results PB7 Use of the project results. To support the project solution in addition to the clearly set work packages and activities, a council of experts has been nominated within the packages, which composes of the representatives of selected target groups, namely: SEVESO establishments Assessors: (private bodies) experts for prevention of major industrial accidents Evaluators: (public bodies) Representatives of the Ministry of Environment of SR Department of environmental risks and biosafety ISBN:

3 2 Comprehensive analysis of the current state of the problem The first partial objective Setting of input and output parameters of the model on the ground of the current state analysis was completed within the Comprehensive analysis of the current state of the problem solved. Completion of the objective was made by the means of: Needs analysis following the lessons learnt from the major industrial accidents prevention in SR and EU Stakeholders workshops Analysis and synthesis of the conclusions of the survey performed among the SEVESO establishments Needs analyses based on the lessons learned from major industrial accidents prevention in SR and EU created one of the prerequisites to define input and output parameters of the model which is a part of the partial objective 2 based on the lessons learnt from these undesirable events. During the stakeholders workshops, the primarily addressed issues were of designing the model and defining the input and output parameters. The added value of these workshops was to identify various perspectives to the problem. The Ministry of Environment of the Slovak Republic as a competent authority sees the problem in the quality of documents prepared by the SEVESO enterprises. Processors of the safety documentation, whether internal or external, do not have the required qualification, experience and often they are provided with the materials from the SEVESO enterprises. The analysis lessons learnt and accomplished stakeholders workshops were subsequently amended by the survey which focused on the issues of major industrial accidents and the fulfilment of the requirements valid for the SEVESO establishments in the Slovak Republic with an emphasis on the implementation of the risk assessment and management. The questionnaire was sent to all SEVESO establishments in Slovakia (80) while the backflow was more than 50%. Based on a survey conducted by the questionnaire method several facts were detected out of which we choose the most important and relevant to the proposed model: Inconsistency of the used approaches and methods of risk assessment and management of industrial processes whereby there is missing possibility to compare results (different algorithms of the approaches based on the economic potential of the subject) Inadequate conditions for the application of the quantitative or qualitative procedures for the risk assessment and management The lack of explanatory documents and methodologies for processing of the required source data necessary for the documentation in question Inconsistency in an approach to assess risks of the natural character considering the ambiguity of data and criteria for their assessment The lack of knowledge on new approaches to the latest technical and technological development in the field of major industrial accident prevention. In addition, the questionnaire survey showed which methods are used by the processors of the documentation. The most common methods used to process the safety documentation include the methods ETA, FTA, security audit, HAZOP, FMEA, expert judgment, QR, ARAMIS, PHA, HRA. One of the problems that is being solved within this project and which resulted from the findings of the stakeholders workshops and the conducted survey within the complex analyses of the current situation, is methodologically unsupported use of the expert method in the process of risk management. Processers of the safety documentation, who perform the risk assessment, very often have no required qualification and experience with competent expert judgment. Therefore, the project also focuses on the elaboration of the methodological support for systematic application of the methods of expert judgment. 3 Methods of expert judgment Expert judgment methods are used in the cases where insufficient size, resp. relevance of data about the problem does not enable us to use conventional statistic methods [3]. The only relevant alternative is to ask the experts for their best professional assessment of the situation. The expert judgment is the base for the subjective interpretation of probability which is in most cases the most suitable way to describe probable behaviour of the given risk or its factors. The method of expert judgment is based on the field of cognitive psychology which deals with assessment and decision making under conditions of uncertainty. This area of psychology examines the way human mind copes with the uncertainty and ISBN:

4 study the specifics and deficiencies of human evaluation in uncertain conditions [4]. Human mind is not a computer and therefore one cannot remember all the events with 100% accuracy. When trying to remember the events and information a person does not usually run statistic calculation to find out what the events really mean. Instead, people use various mental shortcuts which the psychologists call heuristics [5]. The heuristics influence the way we remember various things and how we interpret what we remember. Heuristics are the primary cause of logical errors when assessing probability of uncertain phenomena and therefore it is necessary for the experts who are involved in the assessment to be aware of various known heuristics and consider them in their assessments. Generally, there is no general formal approach which would be applicable in every situation of the expert judgment of uncertainty. However, it is possible to establish some general principles on which this approach should be grounded [6]. The first and fundamental principle is that the process of expert judgment can never be approached as a routine procedure. An inevitable prerequisite of the successful implementation of this method is that the expert judgment analyst devotes adequate attention and sufficient time to careful preparation and planning. Each expert judgment should be considered unique and specific case and it should be organised accordingly. The second principle is that the experts participating on the assessment must be sufficiently familiar with the planed approach and it is particularly necessary to ensure consistent understanding of the problem of assessment psychology and its specifics which form the ground of the selected approach. Familiarity of the experts with the subject and resources of the expert judgment can also play important role in understanding the seriousness and analyst s genuine interest in expert judgment and accordingly, they should approach the assessment in a professional manner. The third principle makes the subject of assessment a central point of the expert judgment. It is therefore necessary for the analyst who organises the assessment to have adequate comprehensive knowledge about the subject of assessment. This knowledge can help the expert to carefully consider and justify their opinions. Through this principle the experts are provided all available information, assumptions, possible interpretations and perspectives as well as known areas which are potential sources of systematic error of assessment considering the given subject. The fourth principle makes sure that the assessed values were defined in appropriate way so the experts could directly and fully use their expertise without previous internal transformation. This principle involves search and correct assessment of correlations and dependencies between the values of various parameters and examination of explicitly unspoken assumptions which are the base for experts judgements. It also involves improvement of the definition of assessed risk or its factor so that it is clear and meets the test of uniqueness. The fifth principle deals with the assessment itself and states that the uncertainty assessment should use the methods for calibration of probability estimates. These methods include [5]: repetition and feedback, equivalent bets, considering pros and cons, avoiding restraint. The method of repetition and feedback is based on the series of tests which evaluate the abilities, preferences and habits of experts while assessing the probability. Each test is evaluated and the feedback provides the expert with a picture of their performances, shortcomings and errors which they do while they make assessment. The method of equivalent bets sets a certain equivalent for each estimation of probability which in fact, represents entirely different situation but with the same probability. At equivalent bets, the most commonly used situations are those where money is at stake as there are studies [7] which prove that it is enough for a person to imagine that his money is at stake and it results into improvement of his ability to estimate his chances. Other used equivalents are situations with pulling coloured marbles from caskets, rolling the dice, examples with cards, etc. The method of consideration of pros and cons is trying to eliminate one of the basic problems of insufficiently calibrated estimations which is the overconfidence of the experts. The base of this method is that the expert looks for the reasons why to be confident that his estimation is correct but also the reasons why he might be wrong. In another words, this method tries to identify and explicitly name the assumptions and suggestions that the experts apply in their estimations. Restraint estimations are one of the fundamental weaknesses of the expert judgments. For majority of people it is natural to think about one number (best estimate) at the first moment, however, they are consequently trying to restraint their estimation by setting an interval around their estimation [8]. This interval is usually more narrow than it is necessary ISBN:

5 for realistic statement of uncertainty. The method of avoiding restraint is based on the search for the interval of reliability by the means of two separate questions providing the value of upper/lower limit of the interval by the confidence rate of the experts about the fact that their estimation of the real value is with certain probability above/below the lower/upper limit. It has been proved [9], that if the confidence rate of the expert is set on 95% than the estimates of the interval limits represent 90% interval of reliability. Required knowledge from the field of expert judgment is one of the partial elements necessary to create a comprehensive model of risk assessment of industrial processes based on new scientific approaches in the process of risk management used in the prevention of major industrial accidents. 4 Conclusion The project MOPORI is currently solving the problem of crating the model of risk assessment of the industrial processes, whereby the basic proposed model of risk assessment of the industrial processes will be applied in two SEVESO enterprises in the Slovak Republic. Based on the findings the conclusions will be made and consequently the advantages and disadvantages of the application of the complex model will be determined and eventually its adjustment related to the detected shortcomings will be made. The next planned step following-up the established model of risk assessment of industrial process is to create a software tool for risk assessment in industrial processes which will be recommended for use by the companies in the Slovak Republic. References: [1] Zanicka Holla, K., Major industrial accident prevention in the Slovak Republic and the project MOPORI, 11th international probabilistic safety assessment and management conference and the annual European safety and reliability conference 2012, Helsinki, Finland, June 2012, pp [2] Salvi, O. et al., F SEVESO: Study of the effectiveness of the SEVESO II directive, EU VRi, [3] Lovecek, T., Ristvej, J., Quantitative assessment parameters of the protection level of national strategic sites in the EU, Risk analysis VII : simulation and hazard mitigation; & Brownfield V: prevention, assessment, rehabilitation and development of Brownfield sites. WIT Press, 2010, pp [4] Lovecek, T., Ristvej, J. & Simak, L., Critical infrastructure protection systems effectiveness evaluation. Journal of homeland security and emergency management. Vol. 7, No. 1, 2010, art. no. 34. [5] Hubbard, D., The Failure of Risk Management, John Wiley & Sons, 2011 [6] Morgan, M., & Henrion, M., Uncertainty: A Guide to dealing with Uncertainty in Quantitative Risk and Police Analysis, Cambridge University Press, 2007 [7] Hoerl, A. & Fallin, H., Reliability of Subjective Evalations in a High Incentive Situation. Journal of the Royal Statistical Society, Vol: 137, 1974, pp [8] Kahneman, D., & Tversky, A. Subjective Probability: A Judgment of Representativeness, Cognitive Psychology, Vol. 3, No. 3, 1972, pp [9] Kahneman, D., Slovic, P., & Tversky, A. Judgment Under Uncertainty: Heuristics and Biases. Cambridge University Press, 1982 This work was supported by the Slovak Research and Development Agency under the contract No. APVV ISBN: