Journal of Health and Safety at Work

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Introduction: The responsibility of achieving sustainable development goals in most megacities and subsequently in Tehran megacity are in charge of the municipalities. Since, the goal of municipalities in environmental-friendly activities is to protect the physical and mental health of citizens. Therefore, the sustainability assessment of health performance in municipalities is one of the most significant issues in the field of municipal sustainable development of megacities. The Objective of this study was to develop a tool for assessing the sustainability performance of Tehran municipality in the field of health- related activities and services.

Material and Method: In this research the main sustainability indicators in the field of health performance were extracted and localized by providing an indicator-based tool for Tehran municipality as a case study. To determine the initial set of effective indicators, guidelines and standards related to health sustainability issues were surveyed, and an initial set of indicators were extracted. Afterward, a two-round Delphi method was applied by 12 qualified experts to select the most robust indicators of Health performance and assign the importance of the inclusion for each proposed indicator on a seven-point Likert scale. The mean value set to 70% and the standard deviation less than 1 were considered as the cut value.

Result: The findings resulted in extracting 11 main categories and 28 sustainability indicators of health performance. The set of indicators related to the “green space” and “waste” categories with slight differences gained the first and second position in the health sustainability field respectively, whereas “urban planning”, “active and healthy life” and “health and hygienic services” located in the bottom of the list with the relatively close scores.

Conclusion: The results of this study showed that due to little difference between the score of the main selected categories (less than 1 point difference between the highest and lowest categories) and also due to the fact that the expert panel reached a consensus on the total 11 categories, therefore  in order to achieve municipal sustainable development and improving the health level of citizens in the future, it is essential to have a robust consideration toward applying engineering and management measures against all 11 selected categories.

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Introduction: Extensive human and economic losses due to the fire accidents shows the necessity of scientifically dealing with major industrial fires, , investing in the development of fire protection technologies and determination of the most effective techniques to limit damages. This study is conducted to evaluate the effect of active and passive protection methods on reducing the level of fire risk, in the control room of a thermal power plant.

Material and Method: In the first phase of this study, fire risk level for buildings, goods, occupants and activities was calculated using Fire Risk Assessment Method for Engineering. In the second phase, from 36 sub-factors affecting risk level, three sub-factors of passive protection measures and two sub-factors of active protection measures were analyzed and modified, in reducing the fire risk level of occupants.

Result: The results of the present study showed that occupants’ fire risk level (20.64) is above the acceptable level. Correction of three sub-factors, including constant fire load, floor number, and changing the dimensions and area of the control room up to 40% and installing an automatic fire extinguishing system and training the occupants to use fire extinguishing equipment and emergency evacuation up to 33%, is effective in reducing the fire risk level.

Conclusion: Passive and active protection methods, despite their impacts on reducing the level of risk, cannot provide an acceptable level of fire safety independently. Therefore, combined use of these methods is essential to protect buildings and people, and prevent any interruption in the system’s activities.

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Introduction: Workers in steel manufacturing companies are extensively exposed to the volatile organic compounds (VOCs). Considering the health effects of these compounds, the purpose of this study was to determine occupational exposure to the BTEX compounds and also evaluation of carcinogenic risk due to benzene and non- carcinogenic risk for BTEX compounds in a steel industry.

Material and Method: This cross-sectional study was conducted in the coke production unit of the steel making industry. After collecting personal samples from breathing zone of the workers and analyzing of the samples the levels of exposure to the BTEX were quantitatively determined using Gas chromatography equipped with Flame Ionization Detector (GC-FID), according to the NIOSH 1501 standard method. Then, cancer risk due to benzene and non-cancer risks from BTEX compounds were calculated using Monte-Carlo technique.

Result: The analysis of personal samples indicated that benzene concentration in energy and biochemistry and benzol refinement sections of the plant were higher than occupational exposure limits (OELs). Among the studied sections, benzol refinement as the most polluted section had the highest concentration of BTEX compounds. Non-cancer risk due to BTEX compounds in all studied sections was lower than one. Benzene cancer risk in energy and biochemistry, benzol refinement and experimental furnace sections was higher than maximum recommended value by EPA.

Conclusion: Due to the high concentration of benzene in energy and biochemistry and benzene refinement sections as well as the resultant carcinogenic risk, improvement of existing control systems and the use of modern engineering systems are necessary to control occupational exposure.

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Introduction: Working in hot and harsh weather conditions can cause heat related diseases and in some cases, even can lead to death. Risk assessment of heat stress in these environments is of particular importance. As there are many factors that could affect the heat stress, therefore, an index should be applied that could properly reflect the effect of all of these factors.
Material and Method: Initially a five-member expert team was established. Then, the weight of each variable was determined by the fuzzy analytical hierarchy process (FAHP) method. In next step, five work stations of the casting process evaluated applying fuzzy TOPSIS (FTOPSIS) method and the risk of heat stress prioritized in these stations. Lastly, the Pearson’s correlation coefficient was used to determine correlation between the results of proposed method with WBGT index.
Result:  The weights of three main variables including task characteristics, working environment, and worker characteristics was determined as 0.279, 0.526, and 0.195. The risk priority of the five work stations including, stocking, melting furnace, pouring and casting, polishing, and warehousing was established as S1= 4, S2= 2, S3= 1, S4= 3, and S5= 5. The Pearson’s correlation coefficient between the similarity index (CCi) and WBGT was 0.97.
Conclusion: From three main variables that can affect the heat stress, “Working Environment” has main impact in the risk assessment process; therefore, the most efforts must be focused on controlling this variable. The proposed method in this study has the capability of concurrent quantitative and qualitative assessment of factors that could affect the heat stress and can minimize the uncertainties in the risk assessment process relying upon the fuzzy sets.

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Introduction: One of the harmful pollutants in the indoor environments is particulate matters. Particles smaller than 2.5 micrometer in diameter that are suspend in the industrial environments air are the most deleterious dusts which can cause lung disease and cancer. In present study PM2.5 concentration in the fast-food shops air and its cancer risk for shop workers were assessed.  
Material and Methods: In this descriptive-analytical study, all of Sari city 132 fast foods were included. Air sampling was conducted by calibrated real-time GRIMM-monitor device. Data were analyzed by using of SPSS16 and Prism6 software with T-test, Pearson correlation and descriptive statistics. Finally PM2.5 cancer risk in workers was calculated by EPA method equation.
Results: The PM2.5 concentration in shops indoor air (308.5µg/m3) significantly was higher than its concentration in outdoor air (121.98µg/m3) (p<0.05). Highest correlation was observed between indoor PM2.5 concentration with smoking (0.366) and local ventilation (-0.384) (p<0.01). The concentration PM2.5 in the indoor and the outdoor of shops was 273.55 and 86.98µg/m3 higher than acceptable level respectively. Cancer risk was 5.6 per 100 thousands and 1.97 per 10 thousands in the rest and cooking time respectively.
Conclusion: The most affective source in the elevation of PM2.5 level in shops indoor air is the cook-emitted particles. PM2.5 concentration in shops indoor and outdoor air was much higher than EPA admissible level and cancer risk for workers was unacceptable that it has required to basic solutions for air pollution control at source.

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Introduction: Evaluating environmental risks in the oil and gas industry is essential to prevent irreparable damage to the environment. Using classical methods for prioritizing environmental risks does not achieve high-reliable results. Therefore, the aim of this study is to minimize the limitations of classical methods in a typical oil and gas production zone, by using fuzzy logic and Multi Attribute Decision Making (MADM) approach.  
Material and Methods: After forming an identification and assessment team including experienced experts from different organizational units in a region of exploitation of oil and gas, values of each risk factor (likelihood of occurrence, severity and detectability) related to identified environmental risks are determined according to their qualitative opinions represented by linguistic variables. Relative weights of the risk factors are calculated by applying the group Analytic Hierarchy Process (AHP) in a fuzzy environment on expert opinions. Then, fuzzy aggregation in the linear form by considering the weight of the risk factors and a method that is developed based on the center of gravity are employed in evaluation and ranking of the risks.
Results: In this study, the severity factor has the most important contribution in risk assessment compared to the other risk factors, since it has the highest relative weight. Raw sewage aspect resulted from absence of appropriate treatment system has the highest priority and spilling over of acid that is caused by chiller cleaning stands at the second position in the identified environmental risks.
Conclusion: The results demonstrate that although the proposed methodology requires greater time than classical methods, it is able to determine the risk ranking more practically because of minimizing the limitations of classical methods: high sensitivity to judgmental errors, considering some risks in the same index group and ignoring uncertainty in experts’ opinions. Proposed method is a proper alternative for classical environmental risk assessment technique, and capable of prioritization and evaluation risks in terms of safety and health.

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Introduction: Hazard Identification, risk assessment and management have an important role in reducing potential risks in industrial settings. This research was done with the aim of identifying the hazard and evaluating HSE risks and providing a HSE management program for the Urea Unit of Shiraz Petrochemical Complex.
Method: Firstly, hazard identification and qualitative risk assessment was done using FMEA technique and risky units were identified. Then, main events were identified and analysed as inputs of the Bow-Tie method. By identifying the strength, weakness, opportunity and threat factors, ranking and weighting them using the ANP method and Super Decisions software, a SWOT matrix was prepared and HSE management strategies were extracted.
Findings: The results showed that chemical leakage, falling from height and slipping were the most important incidents, and defect of control equipment, lack of attention to instructions, non-compliance with safety principles and human error were causes of these events. Also, ranking of weaknesses, strengths, opportunities and threats were 0.58, 0.2, 0.16 and 0.05, respectively.
Conclusion: Organizational opportunities with a weight of 0.124 were 4.8% higher than threats with a weight of 0.076. This shows that the company had a good situation in terms of achieving its goals.

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Introduction: Risk identification and investigation is an appropriate and practical approach for the occupational health professionals. This paper aims to determine exposure to the gases and metal fumes and to perform risk analysis in three common types of welding activities in a shipbuilding industry.
Material and method: This analytical cross-sectional study was conducted in a shipbuilding industry and three types of welding were considered including SMAW, MIG and MAG welding. Sampling of Mn and Cr fumes was carried out using NIOSH 7300 standard method, and NIOSH 6014 method NO2 sampling, and also direct reading devices for CO and O3 gases. Moreover, SQCRA risk assessment method was adopted to specify the level of exposure risk.
Results: The results of risk analysis showed that among gas pollutants, O3 and NO2 in all welding processes had a very high-risk level, while among the metal pollutants; Mn metal showed a high and very high risk level in MIG and SMAW welding.
Conclusion: According to the both sampling results and risk analysis, MIG process welders are more dangerous position than other types of welding.

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Introduction: Commercial complexes are one of the most prestigious public and city-centered areas in terms of urban safety and passive defense. The purpose of this study was to determine the fire safety risk score of commercial complexes and its related factors.
Material and method:  The commercial complexes of area 1 of District 12 of Tehran were studied. The characteristics of the complexes, including construction, height, activity, Occupancy Coefficient and etc in each complex were collected. fire risk assessment was performed using NFPA101 standard and CFSES software in three areas of control, Egress and general safety. In SPSS software version 21, linear regression and ANOVA tests were used to determine the relationship between variables.
Results: Of the 79 commercial complexes studied, only 8 in control area and 4 in general area achieved acceptable risk level. None of them achieved an acceptable score in the Egress. According to the results, there was no significant relationship between risk levels and height, type and activity Coefficient of them(p>0.05). However, between Occupancy Coefficient of complexes with fire safety risk levels of control(p<0.001) and general(p= 0.013) and between construction with all risk levels ((p_Egress= 0.004), (p_Control & p_General<0.001)) There was a significant relationship.
Conclusion: The results showed the current situation of the studied commercial complexes is prone to cause a disaster in the 12th district of Tehran; Using the results of this study in urban planning and cross-sectoral communication to improve the safety of commercial complexes in the region is suggested.

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Introduction: Styrene (C₆H₅CH=CH₂) is known as one of the volatile organic substances produced or used in petrochemical industries. Exposure to this chemical compound can thus lead to respiratory diseases. Therefore, this study aimed to evaluate occupational exposure to styrene vapor and to determine the risks of its health consequences in petrochemical industry workers through a quantitative method.
Material and Methods: In this descriptive cross-sectional study, a total number of 150 samples from 50 employees were studied using the National Institute for Occupational Safety and Health (NIOSH) 1501 method. The samples were then analyzed by the Varian CP-3800 chromatograph. Upon determining exposure to styrene vapor, the risk assessment of the health consequences of styrene in the workers in the given industry was evaluated via the relationships established by the United States Environmental Protection Agency (US/EPA).
Results: According to the results, the polybutadiene latex unit (PBL) was observed with the highest average exposure (0.44 mg.(kg-day)-1). Therefore, the top predictors of carcinogenic and non-carcinogenic risks were valued 0.44 and 0.71, respectively, for the PBL unit. Given the lowest average exposure (0.0012 mg.(kg-day)-1) in the drying unit, the prediction revealed the most moderate carcinogenic (0.1 ×10-5) and non-carcinogenic risks (2×10-3) for the same employees.
Conclusion: Overall, the health risk was higher than the permissible limit in the petrochemical industry studied, especially in the PBL unit. Therefore, it is recommended to make use of artificial ventilation, notably the local type, in addition to the natural ones.

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Introduction: Assessing health, safety, and environment (HSE) performance based on up-to-date analytical models like resilience engineering, especially in automobile manufacturing companies, affected by the trilogy of HSE factors and functions, is of crucial importance. Therefore, this study was to review the factors effectively involved in HSE management performance assessment based on resilience engineering in automobile manufacturing industries.
Material and Methods: To collect and classify the data, many relevant articles and procedures published in journals or presented at seminars were researched and cited. In this study, reliable online databases, including Google Scholar, Web of Science, Scopus, and PubMed were searched to meet this purpose. Other databases in Farsi such as Magiran, CIVILICA, and Scientific Information Database (SID) were also employed. Accordingly, a total number of 211 articles were extracted and filtered in terms of content and topic by a team of four HSE senior experts, whereby irrelevant studies were deleted, the full text of each relevant article was more closely considered, and finally 18 studies were selected and thoroughly examined.
Results: The findings from these 18 articles revealed that the HSE would be influenced in various industries by factors such as organizational culture, learning and training, political-economic variables, workforce qualifications and skills, strategic and large-scale programs of organization plus its assets and financial resources. In automobile manufacturing industries as well, circumstances might emerge because of some extra-organizational threats and intra-organizational weaknesses, whereby the appearance of deficiencies in various processes and even the functions of the HSE as a whole would be impaired. Of the many external factors, one could mention economic sanctions, large-scale socioeconomic problems, and lack of materials and production equipment. The internal problems would also range from production reduction and cuts in budgets earmarked for different management departments to a rise in the number of accidents and diseases, soaring medical treatment costs, as well as growing expectations in employees, which together impact the HSE management performance.
Conclusion: Regarding the studies conducted on various models presented so far in the area of resilience, it was concluded that the HSE performance of organizations intended to prevent and control risk factors were by no means distinct from other management factors and strategic decision-making in an organization. Rather, the HSE indicators could be impacted by many extra- and intra-organizational factors. Based on the models surveyed, it would be essential to consider the concept of resilience in HSE management. The reason for this is that the idea of the HSE would appear to be an issue of less virtue and importance in various stages and situations in the lifecycle of an organization, which is not consistent with the HSE management system and does not keep pace with the influencing factors.

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Introduction: The development and implementation of effective safety educational program for minimizing hazards in a farm, is the most important activity that can be done to improve safety level there. This program, however, requires to needs assessment process. So, the present study was designed to analyze of the educational needs of farmers in the field of agricultural occupational health.
Material and Methods: This quantitative study was conducted with a survey method. Statistical population consisted of farmers in Mahidasht County, Kermanshah Province, Iran (N =213), where 140 farmers was selected as sample by simple random sampling method and base on Krejcie & Morgan table. Research instrument was research made questionnaire that its validity confirmed by a panel of experts and the reliability was confirmed through a pilot study and calculation of Cronbach’s alpha coefficient. SPSS/16 software was used for data analysis.
Results: Findings showed that educations in the field of occupational health were done neither sufficient nor according to the principles. Educational needs identified in the area included exposure to noise, exposure to dust, ergonomic issues, compliance with hygiene and protection principles in spraying, individual protection in working with tractors and other machinery.
Conclusion: Dangers of farming in one hand and the lack of appropriate education and  the farmers’ dissatisfaction in the other hand, has highlighted the necessity of implementing correct eductional programs according to needs assessment principles in Mahidasht County. In this regard, considering the knowledge and occupational health behaviors of the studied farmers, they need to receive education in most areas of health, among which, environmental hazards (sun and noise, dust on farms), ergonomic issues, proper and safe use of chemical input and adherence to safety principles in working with agricultural machinery are considered priorities.

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Introduction: Chemical industries often have risks for the environment and communities, due to the use of complex facilities and processes. Also, in the ammonia tanks, the probability of risk of explosion is high, owing to their specific characteristics. The aim of this study is to evaluate the risks of explosion scenario at the ammonia tank in the Kermanshah petrochemical complex
Material and Methods: To achieve the purpose of this study, the Fuzzy Fault Tree Analysis (FTA) method was used to estimate the probability of reliability in the basic events. In this study, after drawing Fault Tree for identifying basic events, the probability of basic events was estimated by means of expert’s elicitation, and the probability of minimal cut sets was computed through Boolean logic gates.
Results: According to the results, the probability of occurrence of the top event was obtained equal to 0/054997. In the minimal cut set prioritizing, the failing of pressure safety valves identified as the most effective factor in the top event occurrence, and afterward failing the control valves and human errors were identified.
Conclusion: This study indicates that, based on expert elicitation, a fuzzy error tree method can be used to assess the risk of various scenarios in the industry. Overall, in assessing the risk of the explosion scenario in the ammonia reservoir, it was found that some minor defects, and even human error, could be considered as a major contributor to the explosion.
 

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Introduction: Working with a computer and workplace conditions expose people to risk factors of musculoskeletal disorders (MSDs). This study aimed to assess posture, examine MSDs, and determine, weigh and prioritize the risk factors among computer users by a neural network algorithm. 
Material and Methods: This descriptive-analytical cross-sectional study was conducted in six phases on computer users in 2019. The status of MSDs was determined via Nordic musculoskeletal questionnaire (NMQ). The factors affecting these disorders were determined by the ROSA method, and then these factors were weighed by the neural network algorithm. The data were analyzed in IBM SPSS Modeler.
Results: The mean age and work experience of the users were 34 ± 6.9 and 1.5 ± 0.7 years, respectively. Most of years were observed at the lower back, neck, and upper back, respectively. The final mean scores of the chair, telephone-monitor, and mouse-keyboard were 3.7 ± 1, 3.6 ± 1.1, and 3.65 ± 1.2, respectively and the final mean score of ROSA was 4.4 ± 0.9. The greatest correlation with the ROSA score was observed in chair (R2 = 0.46), followed by telephone-monitor (R2 = 0.43), and mouse-keyboard (R2 = 0.42). The highest predictor importance of the effective factors based on the neural network algorithm prioritization belonged to the chair (48%), followed by telephone-monitor (28%) and mouse-keyboard (24%). The accuracy of the neural network algorithm in examining the effect of factors on musculoskeletal disorders was 98% based on the ROSA score.
Conclusion: Factors affecting years due to working with computers are the chair, telephone-monitor, and mouse-keyboard, respectively, as prioritized by the neural network algorithm. These disorders can be prevented by ergonomic modification of users’ chairs and correct placement of the monitor and telephone.

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Introduction: Labor is one of the most important wards of hospital, where human error is high. Midwifery errors in the maternity ward and in the delivery can be a serious threat to the health of the mother and the infant, resulting in increased treatment costs. Factors affecting human error are diversity in work, high workload, and fatigue. Therefore, this study aimed to evaluate the midwifery errors in the maternity ward using the systematic human error reduction and prediction approach (SHERPA) technique.
Material and Methods: This cross-sectional study was conducted in 2019, during which different midwifery tasks were determined in four stages of admitting, pre-labor, delivery, and postpartum. Tasks and sub-tasks were identified using the hierarchical task analysis (HTA) technique and human error was evaluated using the SHERPA technique.
Results: The results of the HTA technique identified 19 main tasks, 52 sub-tasks, and 114 activities. After assessing human error risk with the SHERPA technique, the performance was the most frequent type of  error and the highest frequency was related to the undesirable risk level.
Conclusion: The errors of the midwifery profession in the hospital’s labor are high-risk and largely critical. Factors such as high workload, time pressure, and fatigue influence the incidence of human error. In order to reduce human error in this area, strategies such as reducing staff workload, developing standard checklists and guidelines are essential to reduce human error in this ward.

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Introduction: In process industries, some of the primary events may result in secondary events in an industrial unit called the domino effect. Since refinery storage tanks are always at risk of fire and explosion, quantitative risk assessment is important in determining the severity and outcome of an accident, taking into account the effects of dominoes on the main industry, neighbors, and society and can play an important role in risk management. Therefore, the purpose of this study was to quantitatively evaluate the risk of condensate storage tanks taking into account the domino effect.
Material and Methods: The technique used in this study was Quantitative Risk Assessment (QRA), the analysis of the consequences of which was performed using PHAST (7.22) after setting goals, studying the process, identifying hazards and scenarios. Then, to determine the extent of the domino effects of the escalation vectors were matched against the threshold, and after screening, the overall vulnerability of the repositories for mapping individual risk levels was calculated.
Results: In the leakage scenario, after considering the domino effects, the risk contour 10-4 to about 250 meters and the risk contour 10-5 to about 400 meters increased. Also in the catastrophic rupture scenario, the radius of risk contour of the 10-5 increased to100 m after considering the domino effects up to around damage tank.
Conclusion: As can be deduced from the results, using this method can give a clear picture of the consequences of chain events and the probability of damage to nearby employees, equipment and neighbors, which is very important in risk, emergency and crisis management.

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Introduction: Human error can occur in many work environments, especially in control rooms. Due to the vital role of the central railway traffic control room in guiding and controlling all types of trains along the railway network, any error in this control room can lead to a catastrophic accident. This study aims to identify and assess human error in the central control room of railway traffic using the HEART technique.
Material and Methods: This descriptive cross-sectional study was performed in 2021. In this research, tasks and sub-tasks were identified using the hierarchical task analysis (HTA) method. Then, the probability of human error was assessed using the HEART technique.
Results: Based on the results of the HTA method, 67 main tasks, and 149 sub-tasks were identified. The study results on the probability of human error using the HEART technique showed that the three main tasks of the traffic expert (distribution of types of diesel, establishing the freight priority, and planning the movement of trains) had the highest probability of error. In addition, the most critical factors influencing human error were “evidence of illness among employees”, “sleep disorder”, “inexperience”, “unfamiliarity”, and “stress”.
Conclusion: The results of this study indicated that the central railway traffic control room employees are prone to errors, and if these staff make errors, irreparable accidents will occur. To reduce the probability of error of these employees, measures should be considered, such as using regular and appropriate shifts, the use of skilled and competent people, and so on.

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Introduction: Failure modes and effects analysis (FMEA) method is used in industries to identify, assess and prioritize risks. Multi-criteria decision-making methods (MCDM) select the best option from different criteria. Therefore, this study aims to identify, assess and prioritize risks using FMEA based on SWARA-VIKOR multi-criteria decision-making methods in a gas pressure reduction station.
Material and Methods: In this descriptive and analytical study, stepwise weight assessment ratio analysis (SWARA) and decision-making optimization and compromise solution (VIKOR) methods were used to rank the risks of failure modes identified in FMEA. SWARA method was employed to determine the severity, probability and discovery weights, and VIKOR technique was applied to rank the failure modes of the system equipment. Finally, an operational example of the pressure reduction station was presented to show the application and feasibility of the proposed model. A comparative study was conducted to confirm the practicality and effectiveness of the proposed model.
Results: In total, 35 main failure modes were identified in the pressure reduction station. Failure of regulator sleeve and safety valve and regulator diaphragm rupture were assigned the first, second and third ranks of risk priority, respectively. The sensitivity analysis results showed the proposed approach had desirable stability and only the failure mode of increasing the heater flame temperature was very sensitive to changes in the weight of the criteria. Results of ranking the failure modes of the station indicated there were many changes in the ranking of failure modes based on the proposed approach.
Conclusion: The proposed approach could provide more reasonable and accurate results for ranking risks because the criteria were weighed step by step based on the experts’ opinion.

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Introduction: Failure Mode and Effects Analysis (FMEA) is a structured way to find and understand the states of a system’s failure and to calculate the resulting effects. In this method, which has been criticized by many researchers, the risk priority number is obtained for each failure mode based on the multiplication of the three parameters of occurrence (O), severity (S) and detection (D). In order to overcome the disadvantages of the traditional method of FMEA, such as ranking the failure and weighting the parameters, this research proposes a model in the fuzzy set.
Material and Methods: The model proposed in this paper is a nonlinear model for weighting the parameters of the FMEA and the revised TOPSIS method for ranking the failures, which is used for the first time to improve the FMEA method.
Results: The proposed model was presented in the Copper Complex of Shahr-e-Babak to assess safety risks. Based on the results of the study, it was found that in this proposed model, the weights of severity and detection were 0.479 and 0.186, respectively, and the results of the ranking showed that the risks of falling from height and getting stuck between objects had the highest and lowest priorities, respectively.
Conclusion: In the proposed model, based on Logarithmic Fuzzy Preference Programming and the revised TOPSIS method, the definite weights of the parameters were presented without any fuzzy number ranking and risk ranking with more criteria, respectively. Therefore, the proposed model has a higher ability compared to the traditional FMEA, and its application can be recommended to determine the ranking of risks.

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Introduction: Human factor analysis has been identified as the most common cause of accidents in natural gas transportation and distribution facilities. The occurrence of accidents at these systems, especially gas reduction stations located in residential and industrial areas, has had catastrophic consequences. Therefore, this study aimed at analyzing critical tasks and human error assessment using the system for predictive error analysis and reduction (SPEAR) method and providing the appropriate framework for error management in the operation and maintenance of city gate stations.
Material and Methods: This descriptive cross-sectional study was conducted using the SPEAR framework and safety critical task analysis guideline to evaluate errors in gas pressure reduction stations. First, critical tasks were screened and evaluated, followed by performing task analysis by the hierarchical task analysis and detecting performance-influencing factors (PIF). Then, human errors were predicted and assessed based on the predictive human error analysis. Finally, error management was developed at three process, equipment, and training improvement levels.
Results: In general, out of 23 operations and 164 sub-tasks, 12 critical tasks were identified based on the results. Criticality level percentages were about 67% high risk, 25% moderate, and 8% low risk. In addition, 134 errors were identified which were mostly related to action (42.53%) and checking (39.55%) errors, respectively. Eventually, communication, retrieval, and selection errors were 8.96, 5.22, and 3.74%, respectively.
Conclusion: The results revealed that action and checking errors had the highest percentages. This method can be applied to appropriate the systems approach to error reduction using the PIF assessment output. The privilege affecting factors include preparing standard operation procedures, implementing a comprehensive training program, and controlling environmental hazards.