مجله مهندسی بهداشت حرفه ای
سال هفتم شماره 1 (بهار 1399)

Nowadays with increasing global competition, companies apply several scientific methods to identify, assess and remove potential failures in production process. The main goal of this study was identification and analysis of potential failure modes in a hydraulic pump manufacturing company by using 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.

First, potential failure modes of production process have been identified by applying opinion of experts. Then, failure modes have been prioritized by proposed method. Proposed approach applies the interval valued fuzzy ANP to determine the weight of each risk assessment factor and a combination of interval valued fuzzy FMEA and interval valued fuzzy TOPSIS for ranking the potential failure modes.

Totally, thirty failures have been identified. The first priority that was specified is inappropriate feed rate with number of 0.83 for relative closeness and the last priority failure is being large bush with number of 0.015 for relative closeness.

The results showed that the proposed approach is applicable for assessing and ranking of failure modes. In addition, consideration of some issues like cost factor, interdependence between risk assessment factors and also modeling the method under condition of interval valued fuzzy uncertainty, affected on the final ranking of failure modes.

Work-related upper limb disorders are one of the major causes of disability in industrial workers. The aim of this study was to Comparison of three methods of NERPA, RULA and LUBA in predicting the risk of upper limb musculoskeletal disorders in the household manufacturing industry

In this cross-sectional study, all employed in the operational sector of a household manufacturing industry, including 346 people, participated in six occupational groups. In order to determine the prevalence of musculoskeletal disorders, Nordic General Questionnaire was used. to predict the risk of musculoskeletal disorders in the upper limbs, LUBA, RULA, and NERPA methods were used. Finally, the data related to the real values of musculoskeletal disorders and the risk values predicted by the three mentioned methods were analyzed by Spearman correlation coefficient and kappa agreement coefficient with SPSS Version 25.

The correlation between levels of musculoskeletal disorders and predicted risk levels in RULA, NERPA and LUBA methods was 0.701, 0.691 and 0.629 respectively (P <0.05). also, the correlation coefficient of predicted risk levels in RULA with its corresponding risk levels in NERPA and LUBA methods was 0.713 and 0.619, respectively (P <0.05).

The results of the present study showed that the best method for predicting the risk of prevalence of musculoskeletal disorders among the different examined tasks was RULA method. Finally, it was determined that none of the studied methods had adequate comprehensiveness to assess all of the four risk levels.

Formaldehyde is a hazardous compound that used as a chemical preservative and disinfectant in medical laboratories and hospitals. The aim of this study was to risk assessment of occupational exposure to formaldehyde in different educational hospitals of Baqiyatallah University of Medical Sciences in Tehran.

 This descriptive cross-sectional study was performed on 72 staffs of different sections of four hospitals. To determine the formaldehyde concentration in the air, the National Institute of Occupational Safety and Health method 3500 was used. The risk assessment conducted in accordance with the proposed method by the US Environmental Protection Agency.

In this study, the Time Weighted Average of 8 hours has a range of 0.01 to 0.08 ppm. The findings showed that the average estimated risk of cancer incidence varies from 1.4×10-4 to 30 × 10-4 for the staff of the hospitals studied and was more than the recommended value (10-6) in the Environmental Protection Agency. the average potential dose varies from 124 to 1149. Based on the results, there is a significant difference between the cancer risk and the potential dose in different hospitals and sections. Also, the maximum average of carcinogenic risk and the potential dose were 30 and 57.5 times higher than the definite risk and the acceptable limit, respectively.

Due to the high risk of formaldehyde, engineering and management control measures are required to protect the staffs.

Nowadays the importance of health, safety and environment issues is becoming more important as urbanization develops and industrial units grow. Due to the lack of a standard questionnaire to assess staff satisfaction with occupational health, safety and environmental management (HSE-MS) status, the present study aimed to design and validate this tool.

In this study, an initial questionnaire including 60 questions was designed with the help of scientific resources and expert opinion. Then, 12 experts in the field of occupational health and health, safety and environment (HSE) were used to standardize and validate the evaluation questionnaire. Content validity index (CVI) and content validity ratio (CVR) were used to validate the questionnaire. Alpha-Cronbach's test was used to test the reliability of the questionnaire, Pearson's test was used to test the correlation between questionnaire scales and KMO's and Bartlett's test were used to determine factor loadings.

The content validity index and content validity of the questionnaire were 0.88 and 0.83, respectively. Also the internal consistency and reproducibility of this designed questionnaire were reported according to Cronbach's alpha coefficient (0.80). In addition, the results of Bartlett's Spear test showed a significant correlation between the variables and KMO statistic value of 840. Is 0.

The results showed that the designed questionnaire was 0.79 and 0.55 in terms of content validity index and content validity ratio, respectively. The alpha coefficient also indicates that the questionnaire is strong in internal consistency.

Increasing the civil incidents including residential fires is a consequence of population growth and development of cities. Residential fire is one of the most important scenarios requiring fast response. Fire response operation encompass various and serious risks for responding team members. Therefore, the present study looks for determining the critical tasks of fire operation response for structural fire scenario through using Task and Training Requirements Analysis (TTRAM).

the present study was conducted in municipal firefighting of Hamadan. Among various operational scenarios, the structural fire scenario was selected for further analysis through expert opinions. The selected scenario was analyzed in details by Hierarchical Task Analysis (HTA). The final selected task were assessed regarding skill decay, practice effectiveness, task sensitivity and teamwork level.

Among 126 task for structural fire scenario, 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 organization showed the highest vulnerability level. 

Due to variety of scenarios and tasks for fire departments, some duties possess higher levels of skill decay potential. Therefore, it is necessary to identify, analyze and manage those activities through a systematic approach.

Mercaptan is used to add odor to natural gas. The current method for deodorizing empty barrels is by sodium hypochlorite and chemical oxidation, which has some problems. In this study, the changes of initial concentration parameters of sodium ferrate nanoparticles, initial temperature and initial pH in the removal efficiency of the odorant were studied.

To evaluate the removal rate of odorant, sodium ferrate nano particles was added to mercaptan as a gas odorant and the effect of different parameters on removal efficiency was investigated.

The results showed that increasing the sodium ferrate concentration, decreasing the initial temperature and pH increased the removal efficiency of the odorant.

The use of sodium ferrate nano particles has been investigated in this research due to the reduction of the oxidation time and the number of chemicals used, the ease of operation with this material, the safe operation, the odorless and non-toxic and high performance.

 Hand anthropometric data can help us properly design hand tools for better efficiency and less fatigue in the individuals. The aim of this study is 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. In order to design the appropriate hand tools, 8 dimensions were measured in Iranian farmers. This study was conducted by measuring the hand dimensions of 600 farmers in four ethnicities of Lor, Kurd, Arab, and Fars in Iran and comparing them with each other, as well as other countries which have measured their employees' hand dimensions to design hand tools appropriate for their countries.Results showed that 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) in Kurds ethnicity; palm length  (10.82±0.84) in Arab ethnicity; and index finger diameter (2.40±0.39) and hand circumference (28.71±1.51) in Fars ethnicity were the greatest values. The results of comparison made between hand dimensions and those of other countries showed that the Iranian metacarpal hand width is larger than countries such as India, northern Nigeria, and Jordan. In addition, the hand thickness of Nigerian people is greater compared to Iranians'. These findings can help interior designers be able to design appropriate hand tools that cause a reduction in ergonomic problems in domestic farmers.

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. The aim of this study was to investigate the effect of organizational leadership and safety climate on occurrence of unsafe behaviors among employees of oil platforms.

This cross-sectional study was performed in 2018 among five oil platform located in the Persian Gulf. The sample size was 291 employees. To assess organizational leadership and safety climate, Multifactor Leadership Questionnaire and standard occupational safety climate questionnaire were used, respectively. The unsafe behaviors checklist was used to determine the occurrence of unsafe behaviors based on the risk factors of accidents that have occurred on the oil platforms during the past 10 years.

There was a significant inverse relationship between transformational and transactional leadership style and the occurrence of unsafe behaviors. The study of the relationship between different dimensions of safety climate and the occurrence of unsafe behaviors showed that there is a significant relationship between the dimensions of safety at work and the probability of ignoring error and the occurrence of unsafe behaviors.

The results of present study showed that transformational and transactional leadership style and also safety at work and probability of ignoring error in oil platforms are important and influential factors in occurrence of unsafe behaviors.