Journal of Health and Safety at Work

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Introduction: Pollutants in gas turbine air intake can cause erosion ،corrosion، fouling as well as reduction of power and efficiency of turbine and noticeable economic losses. In order to select the appropriate filtration system, air monitoring of turbine inlet and its filtration is essential. Therefore, this study was performed to assess the quality of gas turbines inlets in a gas power plant in Tehran.

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Material and Method: In this cross- sectional study, the concentration of particulates contained in air intake of 4 types of gas turbines, including: Fiat, Assec, Hitachi and mitsubishi were evaluated in second-half of spring season. For this means, 12 series of air samples were collected using 8 stages cascade Impactor, model AN -200 made by OGAWA company on cellulose – ester filters . The dust concentrations were determined gravimetrically in different ranges of sizes . Then the concentrations of 8 metals including Sodium, Potassiumu Lead, Mercury, Aluminum ,Copper and Cadmium were measured using ,Atomic Absorption Spectroscopy method and the data were statistically analyzed by SPSS Software, version16.

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Results: The results showed that the mean of particulate concentration with the diameter less than 4.7 µ were 64% ,66% ,60% ,67% for Fiat, Assec, Hitachi, mitsubishi respectively and it was 64.25% totally. The concentrations of all assessed metals in particulates less than 4.7 µ were greater than of larger than 5 µ. There were not any differences between particulate concentration in the inlet of Fiat and Hitachi (P>0.05), while in the case of other gas turbine intakes , there were statistically significant differences (P<0.05).

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Conclusion: Based on mass distribution of particles, the highest concentration belongs to particles with diameter of less than 4.7 µ. These particles could damage turbine blades, especially due to the presence of sodium and potassium as corrosive elements in this range (200 µg/m3). Therefore,this range of particle size must be considered in selecting the air intake filtration system.

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Introduction: Safety culture is considered as the core of an organization’s safety management system. Safety culture is an organization ability to achieve higher standards of safety. The aim of this study was to investigate safety culture and its influencing factors and relation to the accident in a dam construction project.

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Material and Method: This cross-sectional study was conducted among 130 workers at a dam construction project. A standardized questionnaire included 59 questions was used to determine the level of safety culture. The accidents occurred in the project during the year were collected based on demographic characteristics. The collected data were analyzed using SPSS version 19.

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Result: The mean age of the subjects, their work experience and score of safety culture were 35.05, 7.5 Years and 183.2, respectively. Twenty seven accidents were recorded during the year in project. The most common cause of the accidents was indiscretions (33.3%). There was a statistically significant correlation between safety culture to occurred accidents and history of accident (P<0.05). The percentage of a positive safety culture of workers with an experience of accident (71.8%) was more than that of those with no experience of accident (45.1%). There was not a statistically significant correlation between safety culture and age, work experience, education, and marital status.

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Conclusion: It seems that safety culture on the project is influenced by the experience of accident and also it was strongly significant with the occurred accidents. Consequently, in order to create a positive safety culture in the workplace many factors including safety education program, work experience and accidents analysis should be considered.

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Introduction: Polycyclic aromatic hydrocarbons (PAHs) are one of the most significant current environmental issues. Phenanthrene and naphthalene adsorption at activated carbon beds prevent the release of these compounds into the environment. The objective of this research was to compare the amounts of phenanthrene and naphthalene adsorption at activated carbon beds in the n-hexane solution.

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Material and Method: This discontinuous experimental study was conducted in the laboratory scale batch and in the n-hexane solution containing phenanthrene and naphthalene.PH values were adjusted by adding hydrochloric acidand 1 N NaOH. The initial and residual phenanthrene and naphthalene concentrations were spectrophotometrically measured at 270 and 266 nm, respectively.

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Results: Findings showed that the maximum adsorption of naphthalene was obtained at pH=5 and contact time of 8 hours (7.4 mg/gr). The maximum adsorption was reached at pH=7 and contact time of 11 hours for phenanthrene (8.34 mg/gr).Improvement in the adsorption capacity was happenedby the increases in contact time and initial phenanthrene and naphthalene concentrations. The adsorption kinetics of these two compounds followed pseudo-second-order and Freundlich isotherm model.

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Conclusion: Freundlich isotherm model showed a strong association with PAHs adsorption process. A weak correlationwas observed between Langmuir theory and the results of the adsorption at activated carbon beds in the organic n-hexane solution.

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Introduction: Safety signs provide information,related to hazards or dangers in the industry,in form of instructions. These signs are effective as long as they are designed in accordance with principles of ergonomics and design cognitive features. The purpose of this present research was to study the relationship between cognitive features of signs and ability to guess, and to develop the relevant regression model.

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Materials and methods: This descriptive cross-sectional study was carried out on 100 employees in a petrochemical industry complex. A three part questionnaire was used to collect required data while first part of the questionnaire dealt with demographic information, second part included cognitive features of signs designand the third part proceeded on testing the ability to guess. Then, a regression model was developed to determine the relationship between cognitive features, and the ability to guess.

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Results: Mean and standard deviation obtained for the ability to guess the total study signs were 63.73 and 4.36, respectively. The feature of “familiarity” obtained the lowest possible score (49.15). The “semantic closeness” (β=0/390) and “meaningfulness” (β=0/369) had the highest correlation with the ability to guess safety signs.

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Conclusion: According to results of this study, use of principles of ergonomic design of signs and training are necessary to promote the ability to guess the safety signs to the minimum available standards. Therefore, it is possible to balance cognitive features especially “familiarity”, with the lowest score, and “meaningfulness” and “semantic closeness”, with the highest influential relationship with the ability to guess of signs. The developed regression model for this industry can be used to predict the ability to guess of safety signs in future studies

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Introduction: Polycyclic Aromatic Hydrocarbons (PAHs) belong to one of the groups of persistent organic pollutants (POPs) which are the result of incomplete combustion of organic materials, volcanic eruptions and forest and agricultural fields’ fires in the environment. However, human factors are main source of these pollutions. Nowadays, these compounds are among the main concerns related to the pollutants which, can easily enter into the land and water systems. Absorption of aromatic hydrocarbons and poly-aromatic molecules on the surfaces of carbon nano-tubes (CNTs) have increased in recent years. In this study, absorption of phenanthrene (as a representative of aromatic hydrocarbons groups) on multi-walled carbon nano-tubes was investigated in organic environment.

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Material and Method: All experiments were performed in a laboratory environment with a temperature of 24±2.Different variables including the type of solvent, solvent volume, pH of the environment, the absorption time of optimal phenanthrene concentration, and the highest removal efficiency under optimized parameters were obtained. Samples were analyzed using HPLC.

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Result: Findings showed that methanol with the volume of 10 ml, and the absorption time of 1.5 hours and 1.3 ppm concentration had the maximum absorption efficiency. Environmental pH had no effect on the absorption efficiency.

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Conclusion: Multi-walled carbon nano-tubes have high absorption capacity for the absorption of phenanthrene. Moreover, in an organic environment, the level of phenanthrene absorption on multi-walled carbon nano-adsorbent was more than 90% and according to the material used was 92%. Day-to-day and within-day reproducibility confirmed the mentioned results.

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Introduction: Noise is one of the most harmful industrial agents and there are different methods to control it. Fuzzy analytical hierarchy process is an appropriate technique for selecting the best choice among several control methods. Therefore, the aim of this study was the selection of the most suitable sound control method using fuzzy hierarchical analysis (FAHP) technique in a refinery plant.
Material and Method: The present study was a cross-sectional research in a refinery plant. After identifying the main sources of the noise in the studied palnt, five criteria and ten noise control methods were selected using a questionnaire and Delphi methods. Then, Fuzzy hierarchy analysis was applied for the selection of the best noise control alternative.
Result: The results showed that the performance with a final weight of 0.277 and the non-interference in the process with a final weight of 0.06 were most and least important criteria, respectively. Meanwhile, worker enclosure had highest score (0.207) of the control methods.
Conclusion: In general, the results showed that best criterion for selection of the suitable noise control method is performance. What’s more, based on the results, worker enclosure was selected as best noise control method in the refinery.

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Introduction: Fire and explosion are the most common consequences of natural gas pipeline accidents. The results of previous studies showed a higher rate of accidents in natural gas transmission lines. Given that a large number of people living in the vicinity of natural gas pipelines with a higher severity of related accidents. The aim of current study was to estimate risks using the method of quantitative calculation of risk and simulation of natural gas pipeline leakage using areal locations of hazardous atmospheres (ALOHA) in natural gas power generation.  
Material and Methods: The method of quantitative calculation of risk was used to identify and prioritize risks. The simulation of the consequences of natural gas pipeline leakage was done by ALOHA software. Calculations of individual and social risks were performed based on statistical data obtained from the literature.
Results: The most serious effect of natural gas pipeline leakage was heat radiation effect of jet flame. Considering three leakage apertures in the natural gas pipeline 80, 130, and 300 mm, individual risks for each leakage aperture were 0.073, 0.114, and 0.569 and the number of deaths was 115, 400, and 3386, respectively. Increases in the leak aperture can lead to an increase in the number of deaths and decrease in the cumulative rate of accidents.
Conclusion: The most serious consequence of natural gas pipeline leakage was heat radiation effect of jet flame. The individual risk and social risk are beyond the acceptable risks range.

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Introduction: Long-term exposure to hand-arm vibration causes musculoskeletal disorders mainly in hand and shoulder. The purpose of this study was to determine the effect of sport and using anti-vibration gloves on the grip strength of workers exposed to the hand-arm vibration.
Material and Methods: In this descriptive-interventionist study, 41workers working in one of the Isfahan metal industries were studied. Data were collected by the demographic questionnaire, hand-arm vibration acceleration measurement was performed based on the ISO 5349 standard and grip strength was measured using the dynamometer device model Jamar. The investigations were performed on 3 groups including sporting moves, using of anti-vibration gloves and combination of sporting move and using of gloves. Twenty workers were selected as control group without exposure to any hand-arm vibration. Data were analyzed by the SPSS-21 software.
Results: Workers’ grip strength difference was significant before and after vibration (PValue<0.001) and grip strength had significant and inverse relation with vibration (PValue<0.001, R= -0.411). Grip strength was higher in the group that used anti-vibration gloves accompanied with the sporting moves compared to before the intervention and significant relation was observed (PValue<0.001).
Conclusion: Vibration affects decreasing in grip strength and grip strength itself can be used as a screening measure for those workers exposed to the risk and diseases related to the vibration. Regular sporting moves and using anti-vibration gloves are effective on improvement of workers’ grip strength and preventing vibration-induced complications.

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Introduction: Safety climate potentially affects safety performance in high-hazard industries. Resilience is a developing concept and is defined as the ability that can affect the continuous improvement of safety performance. The present study assesses the influence of organizational resilience on workers’ safety performance in a steel-manufacturing industry. In this regard, the safety climate mediates the effect of organizational resilience on safety performance.
Material and Methods: A cross-sectional study was accomplished in the steel manufacturing industry in 2021. The survey included three parts: (1) organizational resilience, (2) safety performance, and (3) safety climate. Besides, the organizational resilience was measured by a scale with six dimensions and 19 items. Also, safety performance was assessed by six items regarding two performance dimensions (i.e., safety compliance and safety participation). In addition, safety climate was measured by 19 items, comprising four dimensions (i.e., safety communication, supervisor safety perception, coworker safety perception, and work pressure).
Results: The structural equation modeling results showed that the organizational resilience and safety climate had significant impacts on safety climate (β = 0.23, P ≤ 0.05) and safety performance (β = 0.43, P ≤ 0.05), respectively. Also, the indirect results indicated that safety climate mediated the relationship between organizational resilience and workers’ safety performance.
Conclusion: The increment of organizational resilience and safety climate improves workers’ safety performance. Besides, organizational resilience and related dimensions (e.g., reporting culture, learning, and awareness) improve the safety performance dimensions (i.e., safety compliance and safety participation).

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Introduction: Many general indicators have been proposed to assess an organization’s safety performance. However, due to their holistic nature, these indicators may not always reflect safety-specific aspects of an organization’s performance. In other words, the nature of an organization’s activities necessitates the use of specific criteria to better reflect safety performance. This study aimed to identify and measure key safety performance indicators using the Delphi method in Alborz Province Electric Power Distribution Company.
Material and Methods: This descriptive, survey-based study utilized the Delphi method to collect the opinions of 11 safety experts in the electric power distribution industry. Opinions were gathered in four phases, and key indicators were determined in the last phase of the study. These indicators were subsequently used to evaluate the safety performance of Alborz Electric Power Distribution Company for three months.
Results: This study identified and documented 34 safety activities. The expert group proposed 20 indicators in the first phase of the Delphi method. In the second and third phases, four and one indicators were eliminated, respectively, because they did not receive the required score. The content validity ratio (CVR) and content validity index (CVI) were calculated for the remaining 15 indices in the fourth phase. The results revealed that the mean quarterly performance scores of Alborz Province electric power distribution districts and departments in 2016, including Nazarabad, Savojbolagh, Mehrshahr, Fardis, West, East, Taleghan, and Eshtehard, were 78.9, 54.7, 78.8, 75.9, 75.7, 80.8, 61, and 83.5 out of 100 points, respectively.
Conclusion: The Delphi method is useful for identifying key safety performance indicators. The indicators discovered using this technique are active indicators (pre-accident) that are crucial in determining Alborz Electric Power Distribution Company’s safety performance. These indicators are suggested for use in evaluating the safety performance of other electric power distribution companies.

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Introduction: Disturbing noise can cause physical and mental illnesses among workers; for this reason, it is necessary to restrain it, especially in workplaces. Using sound-absorbing materials with suitable acoustic properties has been a growing trend in mitigating noise. This study aimed to improve the acoustic properties of polyurethane foam (PUF) as a sound absorber.
Material and Methods: In the present study, PUF was synthesized with different percentages of clay nanoparticles (0 -1.2 wt.%), and then the Sound Absorption Coefficient (SAC) of the synthesized PUF was measured by the acoustic impedance tube in the frequency range of 63 to 6400 Hz according to the ISIRI 9803 standard without an air gap behind the sample. The morphology of the foam was also investigated by Scanning Electron Microscope (SEM).
Results: The results showed that the addition of clay nanoparticles to PUF improved the sound absorption behavior of the samples, and the best sound absorption behavior was for PUF with 1.2% weight of nanoparticles at low frequencies (500-2600 Hz). This increase in the absorption coefficient can be due to the increase in the number and smaller size of the pores with the increase in the amount of nanoparticles in PUF.
Conclusion: This study illustrates that the incorporation of clay nanoparticles into PUF at varying percentages results in an enhanced absorption coefficient. The presence of clay nanoparticles leads to a reduction in cell size and an increase in the number of pores, consequently enhancing surface friction. The absorption coefficient was observed to increase with the growing concentration of clay nanoparticles in PUF.