JOURNAL OF OCCUPATIONAL HYGIENE ENGINEERING
Year:2020 | Volume:7 | Issue:1|Papers Count:8

Background and Objective: Nowadays with the increase of global competition, companies apply several scientific methods to identify, assess, and remove potential failures in the production process. In this regard, the present study aimed to identify and analyze the potential failure modes in a hydraulic pump manufacturing company by using a combination of interval valued fuzzy analytic network process (IVF-ANP), interval valued fuzzy failure mode effect and analysts (IVF-FMEA), and interval valued fuzzy TOPSIS (IVF-TOPSIS). Materials and Methods: For the purposes of the study, first, the potential failure modes of the production process were identified using the opinion of experts. Then, the failure modes were prioritized based on the proposed method. The proposed approach applied the IVF-ANP to determine the weight of each risk assessment factor and a combination of IVF-FMEA and IVF-TOPSIS to rank the potential failure modes. Results: In total, 30 failure modes were identified in the present study. The highest-ranking failure mode was inappropriate feed rate with a relative closeness of 0. 83. On the other hand, the lowest-ranking failure mode was the large size of the bush with a relative closeness of 0. 015. Conclusion: The results showed that the proposed approach is applicable for the assessment and ranking of failure modes. In addition, consideration of some issues like the cost, interdependence of risk assessment factors, and also modeling the method under the condition of interval valued fuzzy uncertainty, affected the final ranking of failure modes.

Background and Objective: Work-related upper limb disorders (WRULDs) are among the main causes of disability in industrial workers. Regarding this, the present study aimed to compare novel ergonomic postural assessment (NERPA), rapid upper limb assessment (RULA), and loading upper body assessment (LUBA) methods in predicting the risk of upper limb musculoskeletal disorders in the workers of household manufacturing industry. Materials and Methods: This cross-sectional study was conducted on 346 employees in the operational sector of a household manufacturing industry, in six occupational groups. The Nordic General Questionnaire was used to determine the prevalence of musculoskeletal disorders. Furthermore, LUBA, RULA, and NERPA methods were employed to predict the risk of upper limb musculoskeletal disorders. Finally, the values measured by the Nordic General Questionnaire and those predicted by the three mentioned methods were analyzed by the Spearman correlation coefficient and Kappa coefficient in SPSS software (version 25) at a significance level of 0. 05. Results: The mean age and work experience of the participants were 39. 52± 4. 81 and 9. 17± 4. 61 years, respectively. The correlation coefficients between the measured and predicted levels of musculoskeletal disorders by RULA, NERPA, and LUBA methods were obtained as 0. 701, 0. 691, and 0. 629, respectively (P<0. 05). Moreover, the correlation coefficients of the predicted risk levels in RULA with the obtained risk levels in NERPA and LUBA methods were 0. 713 and 0. 619, respectively (P<0. 05). Conclusion: The results of the present study revealed the RULA method as the best technique for predicting the risk of the prevalence of upper limb musculoskeletal disorders among the different examined tasks. Finally, it was determined that none of the studied methods had adequate comprehensiveness to assess all of the four risk levels. Therefore, it is suggested that newer methods be developed based on the correction and better division of angles.

Background and Objective: Formaldehyde is a hazardous compound used as a chemical preservative and disinfectant in medical laboratories and hospitals. The aim of this study was to assess the risk of occupational exposure to formaldehyde in different departments of educational hospitals of Baqiyatallah University of Medical Sciences in Tehran, Iran. Materials and Methods: This descriptive cross-sectional study was performed on a total of 72 staff in different departments of four hospitals using the census method. The National Institute for Occupational Safety and Health method 3500 was used to determine the formaldehyde concentration in the air samples. The risk assessment was conducted using the proposed method of the United States Environmental Protection Agency (EPA). Results: In this study, the time-weighted average of 8-hour exposure was determined within a range of 0. 01-0. 08 ppm. The obtained findings showed that the average estimated risk of cancer incidence varied from 1. 4×10-4 to 30×10-4 for the staff of the studied hospitals and was higher than the recommended value (10-6 ) of the United States EPA. The average potential dose varied from 124-1149. Based on the obtained results, there was a significant difference between cancer risk and potential dose in different hospitals and departments. In addition, the maximum averages of carcinogenic risk and potential dose were 30 and 57. 5 times higher than the definite risk and acceptable limit, respectively. Conclusion: Due to the high risk of formaldehyde, it is required to take engineering and management control measures for the protection of the staff in hospitals.

Background and Objective: Currently, due to the development of urbanization and growth of industrial units, the issues of health, safety, and environment are more important. The present study aimed to design and validate a tool for the assessment of staff satisfaction with occupational health, safety, and environmental management system (HSE-MS) status due to the lack of a standard questionnaire in this regard. Materials and Methods: In this study, an initial questionnaire, including 60 items, was designed with the help of scientific resources and expert opinions. Then, the opinions of 12 experts in occupational health, safety, and environment were used to standardize and validate the assessment questionnaire. Content validity index (CVI) and content validity ratio (CVR) were utilized to validate the questionnaire. Cronbach's alpha was used to evaluate the reliability of the questionnaire, and Pearson's correlation coefficient was utilized to assess the correlation between questionnaire scales. Moreover, Kaiser-Meyer-Olkin (KMO) and Bartlett's tests were applied for the determination of factor loadings. Results: The CVI and CVR of the questionnaire were calculated at 0. 88 and 0. 83, respectively. Furthermore, the internal consistency and reproducibility of the designed questionnaire were confirmed according to Cronbach's alpha coefficient (0. 80). In addition, the results of Bartlett's test showed that there was a significant correlation between the variables, and the KMO value was reported as 0. 840. Conclusion: The obtained results of this study showed that the CVI and CVR of the designed questionnaire were higher than the standard values of 0. 79 and 0. 55, respectively. The obtained Cronbach's alpha coefficient also indicated the strong internal consistency of the questionnaire. Therefore, the designed questionnaire for the assessment of staff satisfaction with occupational HSE-MS status can be useful in present industries with regard to acceptable validity and reliability.

Background and Objective: Population growth and development of cities has several consequences, including an increase in residential fires. Residential fire is one of the most important scenarios requiring quick response which encompasses various and serious threatening risks for responding to team members. Therefore, the present study aimed to determine the critical tasks of fire operation response to structural fire scenarios using Task and Training Requirements Analysis Methodology. Materials and Methods: The present study was conducted on 10 fire stations in Hamadan, Iran. Among various operational scenarios, the residential fire scenario was selected for further analysis using expert opinions. The selected scenario was analyzed in detail by Hierarchical Task Analysis. The final selected task was assessed regarding skill decay, practice effectiveness, task sensitivity, and teamwork level. Results: Out of 126 tasks for residential fire scenarios, 54 tasks encompass the most skill decay potential and 71 tasks include the highest level of team supporting activities. Considering the sensitivity and teamwork level, 9 tasks had the highest levels of vulnerabilities. Securing the incident scene in coordination with other organizations showed the highest level of vulnerability. Conclusion: Due to the variety of scenarios and tasks of firefighter teams, some duties possess higher levels of skill decay potential. Therefore, it is necessary to identify, analyze, and manage those activities through a systematic approach.

Background and Objective: Mercaptan is used to add odor to natural gas. The current method utilized for deodorizing empty barrels by sodium hypochlorite has been carried out through chemical oxidation and reported with some problems. In this regard, the current study investigated the changes in the initial concentration parameters of sodium ferrate nanoparticles, initial temperature, and initial pH in the removal efficiency of the odorant. Materials and Methods: To evaluate sodium ferrate nanoparticles in different concentrations, mercaptan compounds were added to the gas odorant, and the effect of different parameters on removal efficiency was investigated. Results: The obtained results of the present study showed that by increasing the sodium ferrate concentrations, the removal efficiency of the odorant increased through decreasing the initial temperature and pH. Conclusion: The use of sodium ferrate nanoparticles was investigated in this study due to the reduction of the oxidation time and number of used chemicals, ease of operation by this material, safe operation, odorlessness, nontoxicity, and high performance.

Background and Objective: Hand anthropometric data can help us properly design hand tools for better efficiency and less fatigue in individuals. This study aimed to measure and analyze hand anthropometric data of Iranian farmers in order to determine the characteristics of farmers' hands separately for each ethnicity so that they can be used to design hand tools and working stations. This study measured 8 dimensions to design the appropriate hand tools in Iranian farmers. Materials and Methods: This study measured the hand dimensions of 600 farmers in four ethnicities of Lor, Kurd, Arab, and Fars in Iran. Moreover, it attempted to compare the data taken from the employees' hand dimensions in each ethnicity separately, as well as those in other countries to design hand tools appropriate for the corresponding country. Results: The results showed the mean length of hand (19. 82± 1. 53), hand metacarpal width (9. 47± 1. 59), hand width to thumb tip (11. 81± 1. 33), and hand metacarpal thickness (2. 78± 0. 29) were the highest in Kurd ethnicity. Moreover, the palm length (10. 82± 0. 84) was the highest in Arab ethnicity. Furthermore, the index finger diameter (2. 40± 0. 39) and hand circumference (28. 71± 1. 51) obtained the greatest values in Fars ethnicity. The results of the comparison made between hand dimensions in Iran and those in other countries showed that the Iranian metacarpal hand width was larger than that in other countries, such as India, northern Nigeria, and Jordan. In addition, the hand thickness of Nigerian people was greater, compared to that in the Iranian population. Conclusion: These findings can help interior designers design appropriate hand tools that cause a reduction in ergonomic problems in domestic farmers.

Background and Objective: Offshore oil and gas platforms have a high potential for major and critical events due to sensitive operating conditions, the existence of critical equipment, and significant volumes of hydrocarbon materials. This study aimed to investigate the effect of organizational leadership and safety climate on the occurrence of unsafe behaviors among employees of oil platforms. Materials and Methods: This cross-sectional study was conducted in 2018 on five oil platform located in the Persian Gulf, Iran. The sample size was obtained at 291 employees. Multifactor Leadership Questionnaire and standard occupational safety climate questionnaire were used to assess the organizational leadership and safety climate, respectively. Furthermore, the unsafe behaviors checklist was utilized to determine the occurrence of unsafe behaviors based on the risk factors of accidents that have occurred at the oil platforms during the past 10 years. Results: According to the results, there was a significant inverse relationship between leadership styles (i. e., transformational and transactional) and the occurrence of unsafe behaviors. Moreover, the study of the relationship between different dimensions of safety climate and the occurrence of unsafe behaviors showed that dimensions of safety at work correlated significantly with the probability of ignoring the error and the occurrence of unsafe behaviors. Conclusion: The results of the present study showed that leadership styles (i. e., transformational and transactional), safety at work, and probability of ignoring errors in oil platforms are important and influential factors in the occurrence of unsafe behaviors.