| 1. |
- Abedi, Parisa, 1968, et al.
(författare)
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Inherent safety evaluation in process plants— a comparison of methodologies
- 2005
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Ingår i: Central European Journal of Chemistry. - 1895-1066. ; 3:4, s. 756-779
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Tidskriftsartikel (refereegranskat)abstract
- Abstract A global population increase and an improved standard of living are generally expected. To meet these demands, an increased production of chemicals will be necessary while protecting human health and the environment. However, most current methods of chemical production are unsustainable. New designs must result in plants that assure process and operator safety, the sustained health of workers and the community, and the protection of the environment. Traditional safety precautions and process controls minimize risk but cannot guarantee the prevention of accidents followed by serious consequences. Therefore, the general approach to environmental and safety problems must be changed from reactive to proactive. One way is to further develop the concept of inherent safety. In this paper some methods for inherent safety evaluations are reviewed. The aim of the study is to analyze the different tools available for inherent safety evaluation and identify the most important criteria in determining the inherent safety of a process plant. A model is proposed to show the interactions of different factors on the inherent safety level of a process and the model is illustrated by a case study.
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| 2. |
- Ajdari, Sima, 1985, et al.
(författare)
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Risk Evaluation of Household Hazardous Waste-A case study
- 2009
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Ingår i: Proceedings of International Symposium on Occupational Safety and Hygiene SHO 2009, 5-6 February, Guimarães, Portugal. - 9789729950452 ; , s. pp. 23-27
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Konferensbidrag (refereegranskat)abstract
- ABSTRACTCertain chemicals in household products, when not used up to the completion at homes, may have the potential to spread hazards. These chemicals consist of heavy metals, pesticides and various types of solvent which may be persistent and can cause severe damage to public and environment. These types of waste shall be collected separately from other waste and are in general destroyed in some kind of specific destruction plant. Everyone who creates hazardous waste is responsible for a proper collection. When it comes to household hazardous waste (HHW) this could be a problem since it assumes that everyone in the society has enough knowledge of how to make a proper collection. Some types of hazardous waste are well-known and easy to recognize, e.g. solvents and batteries, but many people do not have any idea about some of the harmful products which they use and waste. Due to the fact that the hazardous waste is spread out in all households and that everyone is responsible for their own collection, leakages into the environment are possible in today's system. Therefore, a fact finding study is needed to be conducted to see: what would be the main causes of the release of household hazardous wastes (HHW) into the environment during the collection and to evaluate the risks of such an event. This study is carried out based on two studies conducted at Chalmers University of Technology and focused on a case related to collection procedure of HHW in Gothenburg city, Sweden. The aim of the study is to develop a framework to find the most hazardous scenarios, the main causes of release of HHW into the environment. The goal is to propose a guide line to improve the collection procedure with lowest or acceptable risk.Initially, by using “what if” analysis the most important possible scenarios have been discovered. The results have been used in constructing a “fish bone” diagram to analyze the collection methods in Gothenburg city in order to discover the most important causes of the release of hazardous waste into the environment. Based on the fact that nearly 20% of the HHWs are not collected at all (reference), the most hazardous scenario is when “there is no attempt to collect the household hazardous waste”. Subsequently a few scenarios of release to nature have been chosen to be investigated by setting up a model for semi quantitative risk analysis. Risk ranking has been performed with the aim of determining areas associated with high and very high risks. Finally, potential improvements have been discussed.
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| 3. |
- Bakti Cahyono, Rochim, 1983, et al.
(författare)
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Safety Evaluation and Improvement in an Ethylene Oxide Reactor
- 2009
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Ingår i: Proceedings of International Symposium on Occupational Safety and Hygiene SHO 2009, 5-6 February, Guimarães, Portugal. - 9789729950452 ; , s. 101-104
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Konferensbidrag (refereegranskat)abstract
- ABSTRACTEthylene Oxide (EO) is one of the essential chemicals in industrial processes. At ambient temperature, EO is an uncoloured gas with a somewhat sweet odour. The market value of EO is very high since its field of application is large. Above all, EO is used as input component in the production of many different chemical products, i.e. bromide fluid, cosmetic and anti-freezing medium in engines.Handling EO is very complicated because of its flammability. It is very dangerous in many ways. If released uncontrollably it is very likely that a powerful explosion will take place. Exposure to EO may also result in health problems. EO is toxic, carcinogenic, caustic and allergenic.The first stage of EO production is direct oxidation of ethylene, which takes place in a reactor under high pressure and temperature. The reaction is exothermic and has a high potential of runaway followed by an explosion. Therefore, the design, operation and maintenance procedures require proper safety concern.The objective of this project is to identify all possible hazards in the process of EO reactor and to introduce some safety actions in order to minimize the risk of potential accidents. Thus, guideline to improve the safety of EO reactor can be proposed.In this study, some risk assessment tools such as HAZOP and FMEA are used to identify the most hazardous scenarios concerning the reaction phase of the process. Operating condition hazards is evaluated using HAZOP, while equipment hazards and failures are analyzed using FMEA. The results of the study in terms of safeguards and suggestions can be used to improve the EO reactor safety.
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| 4. |
- Bergh, Maria, 1987, et al.
(författare)
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Occupational Safety Climate and Shift Work
- 2013
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Ingår i: Chemical Engineering Transactions. - 2283-9216. ; 31, s. 403-408
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Tidskriftsartikel (refereegranskat)abstract
- Developing and maintaining a rich safety culture is an important factor in achieving a safe workplace with low injury rates. Safety climate measures provide a snapshot of the safety culture, as they reflect workers' shared perceptions of how management and workers deal with safety on a daily basis. There is however, research evidence that safety may be compromised for shift workers during night shifts. The role of safety culture has been documented in major accidents such as Three Mile Island, Chernobyl and Exxon Valdez, all of which involved work activities at night. There is also evidence that workers who work in close proximity to production lines have increased injury risks. This study investigates whether the level of safety climate is lower among shift workers, who work both days and nights compared to daytime workers. The Nordic Occupational Safety Climate Questionnaire (NOSACQ-50) is used to evaluate the safety climate. The questionnaire contains 50 positively formulated and negated (reversed) items using a four-point Likert scale. The items are distributed across seven scales dealing with: Perceptions of management and worker commitment and priority to safety, safety empowerment from management, safety justice, safety communication and trust in safety systems. Data are derived from workers at two chemical plants in Sweden, both of which employ daytime workers and shift workers. Two-tailed t-tests of the data are carried out in SPSS, and are supplemented with injury data and the type of work with proximity to production lines. The level of safety climate is relatively high at both plants, compared to other international studies using NOSACQ-50. Shift workers at the two plants have significantly lower scores on all seven safety climate scales, compared to daytime workers at the two plants. Separate analyses for each plant reveal that shift workers have significantly lower scores on five safety climate scales at the first plant, whereas there were no differences between shift workers and daytime workers at the second plant. Several of the daytime workers at the first plant are located further away from production lines and laboratories than the other three groups, and they experience fewer direct accidents and/or dangerous situations at work. Greater risk exposure and experience with injury events may play more important roles than shift work itself, in explaining lower ratings of safety climate.
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| 5. |
- Bitaraf, Saminehsadat, et al.
(författare)
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Risk Assessment and Decision Support
- 2012
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Ingår i: Internationa Symposium on Occupational Safety and Hygiene, 9th - 10th February 2012, pp 65-69. - 9789729950490 ; , s. 65-71
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Konferensbidrag (refereegranskat)abstract
- Typically, oil production activities contain many hazardous scenarios which could cause catastrophic disasters such as loss of asset, human fatalities or injuries and environmental pollutions. Essence of designing a safe process plant and delivering sustainable performance makes an efficient risk management plan necessary for promoting safety in hazardous industries such as oil production. Risk management activities including hazard identification and risk assessment support decision makers to manage the relevant risks and take appropriate actions to reduce the critical risks levels and contribute sustainable development. In spite of abundant number of tools, techniques and methodologies to apply risk management, there are still some difficulties to address uncertainties associated with decision making during different phases of a project life cycle. Furthermore, in most decision making models, there isn't a clear distinguish between the key components of risk management process e.g. risk, uncertainty, hazard, and feeling threat. The aim of this paper is an attempt to present an efficient model to provide an appropriate decision making approach under the uncertain situation. An oil field development plant is selected as a case study to apply the presented model and assess related risks and uncertainties during the basic design phase of the project in order to demonstrate the efficiency of the model. Three main categories are identified as the major causes of hazard situations in the oil field development plant which are technical causes, organizational causes, and political issues. The required considerations and appropriate actions to reduce the level of risks levels as a result of identified variables have been analyzed for the selected possible hazardous scenarios.
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| 6. |
- Dannberg, Johanna, et al.
(författare)
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Evaluation of an incident causation model- a case study
- 2011
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Ingår i: International Symposium on Occupational Safety and Hygiene, 10th-11th February 2011. - 9789729950476 ; , s. 235-239
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Konferensbidrag (refereegranskat)abstract
- AbstractThe chemical process industry is a high risk industry, in which incidents can have devastating consequencesincluding loss of both lives and property. Organizations use different tools to minimize risks and to reduce theconsequences of incidents. One tool is causal categorization for the purpose of revealing trends in causaldata and to benchmark areas in need of improvements. By reporting, investigating and categorizing causesinvolved in the development of accidents, incidents and near misses, an organization can learn from theirhistory and avoid similar events in the future. Despite focus on safety in the chemical process industry, majoraccidents continue to occur. In this paper the study is focused on an incident causation model used by arefinery located in Gothenburg, Sweden to evaluate the strengths and weaknesses. The events thatoccurred in this refinery, i.e. accidents, incidents and near misses, chosen for the evaluation were allconcerned with process safety. The aim of the study is to approach some critical factors for categorization ofcauses. The results of the study will be used to develop an alternative causation model, which can be usedas a tool to reduce recurrence of unwanted events. The findings shows that a comprehensive model isneeded to benchmark problems within an organization that are not obvious when investigating singleoccurrences. Furthermore, the pre-requisite of revealing interesting trends is that the registered data is ofgood quality and the predefined checklists represent all the relevant underlying causes. To achieve a reliabledatabase, one conclusion is to have an expert investigator to categorize according to the causal model. Eventhough an expert investigator would demand extra resources, it would be worthwhile resulting in a reliabledatabase of underlying causes.
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| 7. |
- Fallahi, Sara, 1985, et al.
(författare)
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Application of Bayesian networks in corrective maintenance safety
- 2011
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Ingår i: Internationa Symposium on Occupational Safety and Hygiene, 10th - 11th February 2011. - 9789729950476 ; , s. 261-264
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Konferensbidrag (refereegranskat)abstract
- AbstractThe emphasis of this exploratory paper is on some maintenance related accidents occurred during previous decades and the aim is to develop a model for preventing such accidents by understanding the major causes and the influencing factors among them. The model is intended to explain the affecting factors in a fatal accident and how they are related to one another. To fulfil the aim of study, a Bayesian network model was developed using the GeNIe 2.0 software and further on the relations between different factors were assigned. The model was developed based on a case study of Tosco Avon refinery accident in Martinez, California occurred on February 23rd, 1999 where four workers were killed in a fiery accident. The proposed model could predict the final result of the execution of a corrective maintenance process to make a safer decision. Since the model was developed based on Tosco Avon refinery accident case, validation has been carried out regarding some other accidents. The results showed that the proposed model is a suitable tool to predict the outcomes of an action in corrective maintenance. In addition the model can be adjusted to different applications.
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| 8. |
- Fouladvand, Sheedeh, 1984, et al.
(författare)
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Fault Tree Analysis, Strengths and Weaknesses
- 2010
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Ingår i: SHO2010: INTERNATIONAL SYMPOSIUM ON OCCUPATIONAL SAFETY AND HYGIENE. - 9789729950469 ; , s. 253-255
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Fault Tree Analysis (FTA) is a tool of hazard identification techniques. As a useful method it is applied in various industries, social and environmental problems for reconstruction, failure analysis, and failure frequency estimation. ETA is a graphical and logic combination of causes of a defined undesired event where Boolean algebra is used. It is a backward method which is used to think about the consequences which may occur. This analysis method is mainly used in the field of safety engineering to quantify the probability of an undesired event and is used to reconstruct it. It can also be used to reconstruct an accident. Besides its advantages, there are a number of shortcomings which imply that the method still has rooms for improvement. Among the disadvantages are the uncertainties in covering all failure modes, inaccuracy in human error in investigation of complex man-made systems and inefficiency of the tool in case of scarce or insufficient data. These problems demand some revision study to find the research questions in detail. The purpose of this paper is to conduct a literature review in order to find weaknesses and strengths of FTA to indicate a platform for future research works.
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| 9. |
- Gustavsson, Mikael, 1983, et al.
(författare)
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Estimation of Maximum Loss - A comparison study
- 2010
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Ingår i: SHO2010: INTERNATIONAL SYMPOSIUM ON OCCUPATIONAL SAFETY AND HYGIENE. - 9789729950469 ; , s. 280-284
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Petroleum refineries are at risk due to the flammability of both the raw material and the products. In addition to the threat to the working force there is also an apparent economical risk associated with the processing of flammable compounds. This economical risk is not only due to the direct impact of a fire or explosion but also includes the cost of business interruption in case of a shutdown due to an accident. As with any situation that involves economical risks refineries may share their risk with insurers. The premium is then based on the size of the financial risk. Thus a decision has to be made by the operator how to share the risk of economical losses with insurance companies at a fair price. However, the decision process is not easy and it generally includes modelling of various scenarios to determine to which extent the process area can be damaged if, for example, a pipe rupture occurs. On the extreme end of modelling the so called Estimated Maximum Loss (EML) scenarios are found. These scenarios try to predict the maximum loss a particular installation can sustain due to an accident. Unfortunately a standard model for estimation of maximum loss does not exist. It means that brokers reach different results on the same scenario due to applying different models and different assumptions. Thus an operator may face uncertainty during the decision process. Hence improvements should be made not only to the models used but also to the concept of EML itself. Therefore, a study has been conducted on a case "Preem Refinery" where several scenarios previously had been modelled by two different brokers using two different softwares, ExTool and SLAM. The aim of this paper is to review the concept of EML and to analyse the used models to see which parameters that influenced the results. The results of the study show that: Overpressure damage threshold values, cloud weights, and releasable inventory are the main sources of deviation in the modelled scenarios; Clear cut-off values for the probabilities of an accident should be used to avoid the "not plausible" argument sometimes heard. As for improving the models themselves, no clear reason for working with threshold values when it comes to overpressure damage can be found. A continuous curve seems more fitting in the age of computers. The possibility to shift such a curve to account for the difference in overpressure sustainability between different types of process equipment could also be explored; and, there are many aspects to investigate further in order to make potential loss predictions more reliable, and this should be well worthwhile since a lot of money is at stake when plant owners and insurers decide on insurance limits and premiums.
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| 10. |
- Gustavsson, Mikael, 1983, et al.
(författare)
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Evaluating EML Modeling Tools for Insurance Purposes: A Case Study
- 2010
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Ingår i: International Journal of Chemical Engineering. - : Hindawi Limited. - 1687-806X .- 1687-8078. ; 2010:Article ID 104370
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Tidskriftsartikel (refereegranskat)abstract
- As with any situation that involves economical risk refineries may share their risk with insurers. The decision process generally includes modelling to determine to which extent the process area can be damaged. On the extreme end of modelling the so-called Estimated Maximum Loss (EML) scenarios are found. These scenarios predict the maximum loss a particular installation can sustain. Unfortunately no standard model for this exists. Thus the insurers reach different results due to applying different models and different assumptions. Therefore, a study has been conducted on a case in a Swedish refinery where several scenarios previously had been modelled by two different insurance brokers using two different softwares, ExTool and SLAM. This study reviews the concept of EML and analyses the used models to see which parameters are most uncertain. Also a third model, EFFECTS, was employed in an attempt to reach a conclusion with higher reliability.
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