JOURNAL OF OCCUPATIONAL HYGIENE ENGINEERING
Year:2018 | Volume:4 | Issue:4 |Papers Count:8

Background and Objective: Incidents are one of the most important causes of damages in an organization often occurring due to a chain of minor and trivial errors. Each error may have minor consequences, but in synergy, the system invariably heads towards serious and disastrous consequences. Therefore, we aimed to identify human errors leading to incidents in a gas refinery using human factors analysis and classification system (HFACS).Materials and Methods: A retrospective study was performed in a gas refinery. Data regarding incidents were gathered from that center. First, root causes analysis reports (RCA) of incidents occurred during the past eight years were prepared. Then, they were analyzed by using the HFACS model.Results: Most errors were associated with the first level, that is, errors caused by unsafe acts, which in the first level they were related to "violations", in the second level to "physical environment", in the third level to "inadequate supervision", and in the fourth level to "management of resources".Conclusion: Our results showed the causes of accidents and several shortcomings in the refinery. Human errors in an organization can be reduced by utilizing administrative controls, creating an appropriate learning environment, and raising employee awareness at the same time.

Background and Objective: Measurement of maximum aerobic capacity (VO2 max) is important in physiologically fitting workers to a specific job. We aimed to investigate the effect of anthropometric and demographic factors on physical work capacity.Materials and Methods: In this study, 60 students of Ahwaz University of Medical Sciences who volunteered to participate were enrolled. For data collection, we used a checklist consisted of two sections. The first section included demographic characteristics, and the second section comprised of anthropometric characteristics of students. The students’ aerobic capacity was assessed by using an ergometer and according to Astrand protocol. Linear regression analysis and Pearson correlation coefficient were run to investigate the association between demographic and anthropometric variables and VO2 max.Results: Mean VO2 max of the students was equal to 2.19±0.56 lit/min and 35.95±8.97 ml/kg-1.min-1. Statistical analysis revealed a robust association between VO2 max and gender, weight, height, body fat percentage (P£0.01), and shoulder width (P£0.04).Conclusion: Among the demographic factors only gender and among the anthropometric dimensions weight, height, shoulder width, and body fat percentage were significantly associated with VO2 max. Therefore, using the regression equations mentioned in this study, it is possible to estimate the physical work capacity according to gender and anthropometric dimensions.

Background and Objective: Toluene is one of the most important pollutants in various industries such as petrochemicals. Absorption of solvents on the substrate is an effective control method for volatile organic compounds. The purpose of this study was to determine the effect of silver nanoparticles on the absorption capacity of (ultra-stable Y) USY zeolite in the process of toluene vapor absorption from the airflow.Materials and Methods: The Ag/USY catalyst composition was prepared using an impregnation method, and 1 g of each adsorbent was placed in a quartz glass cylinder with a length of 25 cm and an inner diameter of 10 mm. In order to maintain a dynamic flow of toluene vapor in the reactor, the impregnation method was used. Input and output toluene concentrations were measured using a direct reading instrument. Effectiveness of the absorbents was determined based on breaking point and adsorption capacity.Results: Dynamic toluene vapor with a concentration of 40 ppm and airflow rate of 0.5 L/min was fully absorbed by 1 g of USY and Ag/USY containing silver nanoparticles (3.9%) in 465 and 873 minutes. Afterwards, the breaking point occurred and absorption gradually decreased, such that the breaking point was saturated at 153 and 162 minutes, respectively, and the concentration of toluene vapor in the reactor outlet was equal to the baseline value.Conclusion: Our results showed that Ag/USY adsorbent containing 3.9% of silver nanoparticles only had a higher breaking time and absorption rate relative to zeolite.

Background and Objective: Appropriate indicators in the evaluation of heat stresses are of particular importance. Therefore, heat stress risk management requires the development of functional indicators. The purpose of this study was to evaluate the performance of the two indicators of WBGT and TWL and their fitness with the tympanic temperature.Materials and Methods: A cross-sectional study of 101 urban service personnel was carried out in a hot and dry area in 2016. WBGT, TWL, airflow velocity, and tympanic temperature were measured using a digital WBGT-meter, TWL software, thermal anemometer, and a tympanic thermometer, respectively. Data were analyzed by using SPSS, version 22.Results: The results of this study showed that the highest correlation was observed between the WBGT index and tympanic temperature (r=0.669) and the lowest correlation coefficient was between the TWL index and tympanic temperature (r=0.343). Considering thermal variations, the absolute magnitude of the correlation coefficient between the WBGT and TWL indicators was higher in comparison with the other indicators (r=0.660), which increases by elevated air temperature, such that at temperatures above 35oC, the correlation coefficient of the two indices reached 0.996.Conclusion: The findings of this study indicated that for the evaluation of the risk of heat stresses in open environments, the TWL index could be considered and applied as a suitable substitute for the WBGT index.

Background and Objective: Repetitive movements and overexertion during occupational activities can lead to musculoskeletal disorders in the upper limbs. Regarding this, the aim of the present study was to assess the ergonomic risk factors of the upper limb extremities using modified Revised Strain Index (RSI) and threshold limit value for hand activity level (TLV-HAL) methods in hand-swen shoe workers in Tabriz, Iran.Materials and Methods: This cross-sectional sudy was conducted on 218 hand-swen shoe workers to assess their stergonomic exposure using the RSI and TLV-HAL methods. The assesment of the study variables was acomplished through direct observation and videotaping of the work-cycles. The data were analyzed by descriptive and analytical methods, such as one-way ANOVA, Spearman correlation, and Kappa statistics.Results: In this study, 218 workers were recruited working in three tasks of preparation (n=69), sewing (n=63), and shoemaking (n=86). The mean scores of RSI for sewing, preparation, and shoemaking workers were 9.30, 46.10, and 95.90, respectively. Furthemore, the mean scores of TLV-HAL for these tasks were 0.27, 0.81, and 1.70, respectively. Almost all workers in preparation and shoemaking tasks were categorized in the group with hazardous level of exposure, while the sewing workers were classified in the group of safe exposure level. The TLV-HAL scores were significantly correlated with the RSI scores.Conclusion: According to the results, the workers in preparation and shoemaking tasks were at a higher risk of upper limbs musculoskeletal disorders due to repetitive actions and overexertion. Therefore, ergonomic interventions are suggested for these tasks to reduce the level of these risk factors.

Background and Objective: The necessity of risk management in construction projects targeted toward the reduction of accidents, achievement of the project goals, guarantee of the organization survival, and achievement of customer satisfaction is inevitable. Therefore, attention to the risk management issue as a part of the macro risk raised in the Project Management Body of Knowledge (PMBOK) can play a significant role in the identification, assessment, and control of the HSE risks.Materials and Methods: This cross-sectional descriptive-analytical study was conducted in 2016-2017 with the aim of analyzing 38 types of risks in four categories of HSE risk in a macro construction project with the PMBOK standard approach. The combined risk assessment was based on the risk matrix, including probability of occurrence and severity factors.Results: The results showed that project cost, quality, and emergency conditions were at a very high-risk level among the four groups of HSE risks in the Work Breakdown Structure. Furthermore, the lack of cost allocation for the employment of HSE supervisor, expert, and officer according to project phases was identified as the highest risk source.Conclusion: This study facilitated an evolution in approaching the project managers' viewpoint to the HSE factors. Moreover, it provided a new approach for the identification of major project risks, examination of the different dimensions of the accident consequences in the project, and application of different areas of PMBOK standard in risk assessment. Consequently, the findings of the present study can be used as a suitable substitute for common risk assessment methods in this industry and similar industries.

Background and Objective: The development of oil and gas extraction industry involve a number of risks, including environmental pollution and the loss of human resources and material assets. Blowout is one of the most significant and costly risks in the oil and gas drilling industry, which could have severe consequences, such as explosion, human fatality, and environmental disasters. Risk assessment is one of the most important tools for designing the measures targeted toward risk reduction and safety enhancement in this industry. Regarding this, the aim of the present study was to identify and analyze the basic causes of kick and blowout in the Iranian onshore exploratory drilling industry by using bow tie analysis and Bayesian network (BN).Materials and Methods: In this study, the identification and evaluation of the basic events leading to a kick was accomplished using the fault trees analysis (FTA). Furthermore, the event tree analysis (ETA) was employed to investigate the safety barriers to blowout and the possible consequences of a kick (e.g., blowout). The potential scenarios of the blowout incidence and the other consequences of a kick were determined through the integration of FTA and ETA by bow tie analysis. Finally, BN was constructed to investigate the blowout probability and other consequences of the incidence of a kick in the well.Results: The results of the study led to the identification of 24 basic events accounting for the incidence of a kick. The data also revealed seven safety barriers for the prevention of the kick incidence. The probability of kick and blowout was calculated as 9×10-2 and 3.5×10-5, respectively.Conclusion: According to the findings, entrance into the high pressure zone and reduction of bottom hole pressure were identified as the most important basic causes of a kick. Furthermore, the early detection of the kick and proper functioning of blowout preventer were recognized as the most important safety barriers to prevent the blowout.

Background and Objective: Performance evaluation and the determination of the effectiveness of management systems, including the Health and Safety Executive (HSE) management system, is inevitable to achieve constant improvement in organizations.Materials and Methods: This study was conducted to evaluate and rank contractors for Health and Safety Executive (HSE) performance using multi-criteria decision making methods of analytic hierarchy process (AHP) and technique for order performance by similarity to ideal solution (TOPSIS) in Imam Khomeini port complex. We also strived to provide management solutions to improve the HSE status of contractors in this complex.Results: After identifying 38 contractors, 4 criteria and 22 sub-criteria were determined by using Delphi technique, and then the criteria and sub-criteria were weighed and prioritized by using the analytical hierarchy process (AHP) method. The management criteria with the weight of 0.586 obtained the highest score and the environmental criteria with the weight of 0.0085 attained the lowest score. Also, the sub-criterion of the HSE professional staff with the weight of 0.272 obtained the highest and green space with the weight of 0.006 obtained the lowest weight. Finally, the contractors were assessed and ranked in terms of HSE performance using the TOPSIS technique. The results showed that in terms of HSE performance T.GH.KH, A.N.A and G.A companies with activity the port and sea service-aridity and vacating and loading installations with arrange points 0.9452, 0.9367 and 0.9264 ranked the first until third place. Also, contractors based on performance HSE were ranked in the three levels of good (9 contractors), moderate (22 contractors), and weak (7 contractors).Conclusion: According to the selected criteria, the performance of HSE management in the majority of contracting companies in a favorable situation. This situation can be attributed to the establishment of HSE management system and the level of contractors' compliance with the HSE requirements.