Journal of Health and Safety at Work

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Introduction: Due to the presence of extreme hazard sources and high intrinsic risk in refineries and process industry sectors, different layers of protection are being used to reduce the risk and avoid the hazardous events. Determining Safety Integrity Levels (SILs) in Safety Instrumented Systems (SISs) helps to ensure the safety of the whole process. Risk Graph is one of the most popular and cost effective techniques to do so. Despite Risk Graph simplicity it’s a qualitative method which is highly subjective and suffers from interpretation problems that can lead to inconsistent or conservative SILs.

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Material and Method: In this paper, Improved Risk Graph (IRG) method was presented and evaluated, and using Fuzzy Logic a novel approach namely Fuzzy Improved Risk Graph (FIRG) was suggested. In the proposed method consequence levels which were defined as qualitative terms were transformed into quantitative intervals. Having those numerical values, risk graph table was converted to a quantitative one. Finally, applying the presented approach and using three experts’ opinions and attributing weight factors, an ultimate numeric value was produced.

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Conclusion: as a result of establishing the presented method, identical levels in conventional risk graph table are replaced with different sublevels that not only increases the accuracy in determining the SIL, but also elucidates the effective factor in improving the safety level and consequently saves time and cost significantly. The proposed technique has been employed to develop the SIL of Tehran Refinery ISOMAX Center. IRG and FIRG results have been compared to clarify the efficacy and importance of the proposed method

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Introduction: Biorhythm is one of the newest subject in the field of cognition of mental ergonomics which can be very effective in reduction of work-related accidents or mistakes with no apparent reason.
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Material and Method: This research is a cross-sectional, retrospective, practical and analytical-descriptive study. Delijan cement production company during 2010-2011. Census method was applied and totally 79 accidents (total of the accidents) were investigated. The required information was collected from available documents in HSE unit of the company biorhythm charts were drawn based on a dates of accidents and participants birthdays, using Natural Biorhythm Software V3.02. Human errors were classified according to reason model and were analyzed by SPSS-W software.
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Result: The results of analysis showed that 40% of accidents have been accrued in usual days and the other 60% in critical days of biorhythm cycle. Regarding errors leading to accidents, it was observed that 95% of accidents were related to human error and 5% related to equipment errors. Moreover, 65.8% of the human errors were associated with the slipping which happens during performing a task, according to reason model.
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Conclusion: Findings of this research showed that bad and critical days of individuals’ biorhythms cycle influence the occurrence of accidents. Therefore, by training and increasing the knowledge of workers regarding biological cycle and its effects on mental, emotional and physical status, each person effects can make some changes to theire work plans during days that they do not feel well, physically or mentally, in order to prevent the likely accidents.

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Introduction: The bank employees usually require the use of computers for long duration in a static position to get the work done. The present study aimed to evaluate the risk factors for musculoskeletal disorder using the ROSA method among the employees of Sepah Bank. An ergonomic intervention was also performed in order to improve the working conditions.

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Material and Methods: This interventional descriptive-analytical study was carried out among 165 office employees of central building of Sepah Bank. Using random sampling, the subjects were initially divided into two groups of case and control. Before and after the intervention, ROSA method and Nordic questionnaire was respectively used to evaluate the risk factors that cause musculoskeletal disorders and the prevalence of musculoskeletal disorders. The data were collected two weeks prior the interventions and 9 months after the interventions. SPSS software version 16 was utilized for data analysis and the effectiveness of intervention was determined.

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Results: Before the intervention, the mean ROSA scores of all groups' workstations were above 5 with high risk. The results obtained 9 months after the interventions manifested a statistically significant decrease (P<0.001) in the ROSA mean scores and its components in the groups who received the interventions. 9 months after the intervention, the prevalence of musculoskeletal disorders among the subjects who had received intervention showed a significant reduction, as well (0.001> p).

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Conclusion: Using the ROSA technique was seemed to be beneficialto assess the ergonomic risk factors of office works, and the deficiencies in the workstation can be identified through this method. Moreover,by design and implementation of an educational intervention program along with engineering interventions which comply with the elements of this technique, the defects can be eliminated.

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Introduction: Due to the importance of engineering controls for prevention of microwave exposure, this study was conducted to design and constract a novel electromagnetic shielding and also to examine the factors influencing shielding efficacy in X band frequency range.

Material and Method: This study used Resin Epoxy as matrix and nano-Nickel Oxide as filler to prepare the composite plates with three different thicknesses (2,4, and 6 mm) and four different weight percentages (5,7,9 and 11). The fabricated composites characterized using X-ray diffraction and Field Emission Scanning Electron microscopy. Shielding effectiveness, percolation depth, and percolation threshold were measured using Vector Network Analyzers. Thermal Gravimetric Analysis was conducted to study the temperature influence on weight loss for fabricated composites.

Result: A maximum shielding effectiveness value of 84.18% was obtained for the 11%-6mm composite at 8.01 GHz and the 7%-4mm composite exhibits a higher average of shielding effectiveness of 66.72% at X- band frequency range. The 4mm thickness was optimum and critical diameter for composite plates; and percolation depth was obtained greater than thickness of composites. However, increasing the nickel oxide content did not show noticeable effect on the shielding effectiveness. Thermal Gravimetric Analysis showed that the study shields were resistant to temperature up to 150 °C without experiencing weight loss. What is more, the results indicated that Nickel oxide Nano particles had desirable distribution and dispersion in epoxy matrix and percolation threshold was appeared in low content of nickel oxide nanoparticles.

Conclusion: A novel electromagnetic shield using low thickness and few content of nanoparticle with noticeable efficacy was properly designed and constructed in the field of occupational health. In addition, this shield has low cost, easy to manufacture, resistance to wet/corrosion, and low weight. Epoxy/nickel oxide composite can represents a new generation of electromagnetic shielding, which is considered as a promising candidate for occupational protection against microwave exposure. It is recommended that future studies improve the shielding effectiveness by decreasing the percolation depth and investigate the efficacy of the fabricated shield in the workplaces.

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Introduction: Exposure to vibration as one of the consequences of industrial noise or the use of vibration generators can cause discomfort, reduce the efficiency and level of safety in workplaces. Therefore, in this study, the effect of whole body vibration on individual’s mental performance and response time was investigated.

Material and Method: In this study, 40 male students of Tehran University of Medical Sciences were selected randomly and divided into two 20 subjects groups. Each group participated in two Pegboard Board and Math Calculations tests. Subjects in each stage of test were exposed to whole body vibration with acceleration in 0.8 and 1.1 m/s2 as well as background mode without vibration and were investigated response time and mental performance.

Result: In the present study, the mean response time to the manual Purdue Pegboard test in the vibrational acceleration of 0.0, 0.8 and 1.1 m/s2 with a decreasing trend was 197.55 ± 2.7, 176.25 ± 5.38 and 177.58 ± 2.92, respectively, which results in a significant reduction in the accuracy of the test. Also, the results showed that whole body vibration does not affect mental performance in shallow levels. But, in the intermediate and deep levels, this difference is statistically significant (p <0.001).

Conclusion: Based on the results, whole body vibration is an effective factor in individual’s response time and mental performance, which can lead to a reduction in the accuracy of the work.

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Introduction: Heat stress is one of the hazardous agents in the steel industries which can threaten the health and safety of workers and lead to serious occupational diseases. The aim of the study was to assess the heat stress in the steel industries and compare PHS (Physiological Strain Index), WBGT (Wet-Bulb Globe Temperature), DI (Discomfort Index) and HSI (Heat Stress Index) indices for the estimation of heat stress and to determine the optimum index for steel industries.
 

Material and Method: This descriptive-analytic study was conducted among 220 workers engaged in two steel industries in Iran. Environmental and physiological parameters were measured according to ISO 7726 and ISO 9886 in three times of measurement, and finally the time-weight average of the heat stress indices were calculated. All data were analyzed using SPSS ver.  20.
 

Result: The time-weight average of WBGT (28.28 oC), DI (29.11 oC), HIS (65.7 %) indices were higher than the recommended limits. Physiological parameters (oral, tympanic and skin temperatures, systolic and diastolic pressures and heart rate) had the greatest value in the second time of measurement (afternoon). WBGT index comparing to the PHS, DI and HSI indices had highest correlation with oral, tympanic and skin temperatures and heartbeat (r=0.314 , 0.408 , 0.459 , 0.302, respectively; P < 0.05), while systolic and diastolic blood pressures showed no significant correlation with WBGT (P > 0.05). The WBGT index had the highest correlation with studied indices which was 0.945, 0.681 and 0.600 for DI, PHS and HSI, respectively.
 

Conclusion: This study assessed the optimal index with regard to the physiological parameters, and it was concluded that the WBGT index has the highest correlation with the most of physiological parameters, and therefore, WBGT index can be the most optimum index to heat stress assessment   in the studied steal industries.

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Introduction: Due to the high prevalence of noise and vibration in workplaces and focused of Previous studies on the auditory and musculoskeletal effects of these two harmful factors, The aim of this study was to determine the protective effect of cinnamon extract on sex hormones levels, body weight and testis weight of adult rats exposed to noise and vibration.  
Material and Methods: 64 male Wistar rats were randomly assigned to eight groups of 8 each. Group 1; treated with distilled water (Control), group 2; treated with 75 mg kg-1 cinnamon extract, group 3; exposed to noise(100 dB), 8 h/day(23:00-7:00) and group 4; exposed to noise and treated with 75 mg kg-1 cinnamon extract, group 5; exposed to vibration(1 m/s2), 8 h/day (23:00-7:00), group 6; exposed to vibration and treated with 75 mg kg-1  cinnamon extract, group 7; exposed to noise and vibration, 8 h/day (23:00-7:00) and group 8; exposed to noised and vibration and treated with 75 mg kg-1  cinnamon extarct by gavage. Fifty days later, the rats were anesthetized, blood samples to determine the amount of sex hormones were collected, and the testis was removed for weight determination. Data was analyesd by SPSS.
Results: Noise stress decreased the level of three hormones (LH, FSH and Testosterone) while vibration decreased testosterone levels merely (P<0.05).Combined exposure to noise and vibration was able to create a significant difference with control group in testosterone and LH hormone levels (P<0.05). The three factors of noise, vibration and combine of them were able to create a significant difference with control group in final body weight (P<0.05). Cinnamon extract increased the level of sex hormones compared to control group (P<0.05).
Conclusion: Cinnamon extract (due to antioxidant properties) has a protective effect on sex hormone levels in rats exposed to noise and vibration. It’s suggested further studies to determine the mechanism of cinnamon extract (in different doses) in human and animal samples.

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Introduction: Stressfull innate of the operating room, unpredictable types of activities, and prolonged standing during surgeries cause chronic fatigue in surgical technologists, resulting in reduced quality of care. It is essential, therefore, to provide especialized methods to reduce the surgical technologists’ fatigue severity.. This study was conducted to evaluate the effect of concomitant exercise and inhalation of lavender fragrance on surgical technologists’ fatigue severity.
Material and Methods: Ninety seven surgical technologists were recruited  in this clinical trial study, working in the operating rooms of Tabriz educational hospitals. They were randomly divided into three groups (Exercise, Lavender & Control) after fulfilling informed consent ,. The instruments for data collection included demographic information form as well as a multidimensional fatigue inventory questionnaire. In the experimental groups, concomitant exercise training and Lavender inhalation were both used for a period of six weeks while no intervention was given to participants in the control group. Statistical analyses were carried out using SPSS 20 as  well as  ANOVA and repeated measurement tests.
Results: No significant difference was observed between Exercise, Lavender, and Control groups regarding demographic characteristics (P>0.05). The mean score of fatigue between exercise and control groups and between Lavender and control groups showed a significant decrease (P<0.05). However, the results showed no significant difference statistically between the exercise and Lavender groups (P>0.05).
Conclusion: The concomitant exercise and Lavender fragrance in the operating room positively affect and reduce the fatigue severity in surgical technologists. Planning to implement similar interventions in the operating room is recommended.

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Introduction: Damage to occupational health is one of the major challenges in the industry. Various studies have shown that productivity in industries has a significant relationship with occupational health. In addition, employee’s health in the workplace can be affected by a variety of variables i.e., job stress, job satisfaction, and work in unconventional shifts. Therefore, the purpose of this study was to evaluate the causal relationships of shift work, job stress, job satisfaction with the occupational health level in a petrochemical industry.
Material and Methods: This cross-sectional study was implemented in 2017. The study sample consisted of 20 HSE experts selected using purposeful judgment sampling. A 4×4 matrix questionnaire consisting of four main parameters i.e., shift work, job stress and job satisfaction with occupational health level, was used for data acquisition. Data analysis was done using MATLAB software and Fuzzy DEMATEL method. Also, for each variable, two key values of D+R and D-R were calculated. These values show the degree of interaction and the type of interaction of the variable with other variables, respectively.
Results: Sixty percent of the experts participating in this study were male and 40.0% were female. Only 10.0% of the participants had a PhD degree. In addition, the mean age and the mean work experience of the subjects were 39.64±9.34 and 10.22±7.10 years, respectively. The parameters of shift work and job satisfaction were identified as an effective factor due to the positive values of D-R while occupational health variable with negative value of D-R, was considered as an affected factor. In addition, these results showed that the effect of these parameters on health is different with both direct and indirect mechanisms.
Conclusion: Using the Fuzzy DEMATEL method, our findings indicated that occupational health in the large industries can be influenced by different parameters with different sizes. Considering the interactions among these parameters in health analysis and the affecting factors, therefore, is very important. So, the health level in challenging industrial environment such as petrochemical industries can be affected by shift work as a root cause. This root cause, along with job satisfaction, has a significant effect on increasing stress levels and reducing health levels. Accordingly, any action to increase the health level should focus on improving shift patterns and increasing the level of job satisfaction of employees as a pivotal root and affecting causes on health level.

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Introduction: This study quantitatively analyzed the fire risk using the Fire Risk Index Method: Multistorey Apartment Buildings (FRIM-MAB) method, considering the importance of fire safety in student dormitories as human gathering centers and previous limited studies.
Material and Methods: This descriptive-analytical study was conducted on 17 sections of the Qazvin University of Medical Sciences student dormitory in 2021. This study used the FRIM-MAB version 2.1. In this method, 17 parameters and their sub-parameters affecting the fire risk index were determined and weighted. Consequently, the studied dormitory was also inspected, the weighted degree of each parameter was computed, and the fire risk index for each section, which ranged between 1 and 5, was determined.
Results: The average fire risk index of the dormitory building at the time of the study was 2.37. The laundry room received the lowest risk index (1.69), while the computer site received the highest risk index (2.7). The results indicated that the most effective parameters causing fire risk were related to “compartmentation” (12 frequency items), “linings in the apartment” (4 frequency items), and “escape routes” (1 frequency item). These parameters contributed more than 42% to create the risk index for the dormitory’s most dangerous areas.
Conclusion: The FRIM-MAB method is a suitable quantitative and indexing fire risk assessment method for student dormitory buildings, and it is a quick, inexpensive, and effective screening and ranking tool. Periodically evaluating the dormitory’s fire risk and, if necessary, improving the environment is essential. In the present study, compartmentation, linings in the apartment, and escape routes were the most effective parameters in fire risk of the studied dormitory.