JOURNAL OF OCCUPATIONAL HYGIENE ENGINEERING
Year:2019 | Volume:6 | Issue:1 |Papers Count:8

Background and Objective: A practical method for noise control in environments with different noise sources is designing an acoustic cabin for the workers. In this regard, this study aimed to assess the efficiency of the acoustic cabin in a typical turbine unit of a thermal power plant to provide acoustic comfort. Materials and Methods: Measurement of the noise level and spectrum, as well as vibration as exposed to whole body were conducted using sound level meter Brü el & Kjæ r 2260 Sound Level Meter; Denmark model 2260. The acoustic cabin was designed using sandwich panel structure based on standard ISO 15667. The composition of cabin walls with 104 mm total thickness from outside to inside included 2 mm steel sheet, 40 mm polyurethane foam with a density of 50 kg/m3, 2 mm steel sheet, 50 mm rock wool with a density of 120 kg/m3, and 10 mm plaster tile, respectively. It should be noted that the floating floor was implemented for the reduction of transmitted vibration to the cabin. Results: The obtained results indicated that the means of noise levels equivalent to sound pressure were approximately 89. 5 and 50. 7 dB outside and inside the designed cabin, respectively, resulting in an overall noise reduction of 40 dB. The results demonstrated that an acceleration level of vibration as exposed to the whole body inside the cabin was lower than the comfort vibration limit of 0. 145 m/s2. Conclusion: In order to design a high-efficiency acoustic cabin, the selection of material types, thickness, and density is critical to optimize the overall sound transmission of the walls. Therefore, the results confirmed that in designing the acoustic cabinet, sandwich panels with adequate mass, low hardness coefficient, and high damping can provide optimal acoustic conditions.

Background and Objective: The emissions, such as Methyl Mercaptan, Hydrogen Sulfide, Dimethyl sulfide and Dimethyl disulfide from dryer machines in cardboard industries cause odor annoyance and affect workers health and that of residents who live nearby. This study aimed to determine the effectiveness of local exhaust ventilation system and packed bed scrubber implemented in the control of hydrogen sulfide from dryer machines of a cardboard industry. Materials and Methods: In this study, the concentrations of emitted pollutants into the breathing zone of workers and the workplace were evaluated regarding on and off settings of the ventilation system as well as before and after the utilization of scrubber for determining the effectiveness of the system designed to control the hydrogen sulfide gas. Results: The efficiency of the local exhaust ventilation system was 55% in reducing individual exposure to the dryer units. The efficiency of the packed bed scrubber in removing hydrogen sulfide from the gas stream was obtained at 91. 7%. Conclusion: The results showed that the local exhaust ventilation system, along with the packed bed scrubber, has a good efficiency in terms of the control of hydrogen sulfide emitted from the dryers, and this system can be a good option for such industries.

Background and Objective: Musculoskeletal discomforts are one of the main problems in all occupations and industries. Printing industry workers are involved in tasks that increase the risk of musculoskeletal discomforts. Therefore, the present study aimed to investigate the relationship of musculoskeletal discomforts with manual load lifting and workers’ postures in a printing industry. Materials and Methods: In the current study, the prevalence of musculoskeletal discomforts among the workers in the printing industry was investigated using the Cornell questionnaire. Manual load lifting tasks in the industry were also assessed in three methods of Snook tables, WISHA, and KIM-LHC. Workers’ postures were assessed using the REBA method. Data were analyzed using SPSS (version 22) through Mann-Whitney U test and Kruskal-Wallis non-parametric tests. Results: The results of the Cornell questionnaire showed that the most common complaints were related to pain in the lower extremities, including feet, legs, and knees. The comparison of the results of Cornell questionnaire and the results of WISHA method using Kruskal-Wallis test showed that the neck (P=0. 016), right shoulder (P=0. 028), left shoulder (P=0. 031), back (P=0. 022), and right forearm (P=0. 045) had a significant relationship with WISHA results. Conclusion: The association of the prevalence of some musculoskeletal discomforts with the results of WISHA method indicated the superiority of this method to KIM-LHC and Snook tables methods for the assessment of manual load lifting tasks in printing industries. Moreover, the lack of correlation between musculoskeletal discomforts and posture assessment using the REBA method revealed that the reasons for the prevalence of these discomforts in the industry should be sought in cases other than inappropriate postures.

Background and Objective: The organization's performance in the field of health, safety, and environment (HSE) education is a prerequisite for the continuous improvement of management systems. Providing successful training requires the recognition and development of effective factors, such as key performance indicators. In addition, the indicators, such as the cost and the educational per capita that are normally being used, are not sufficient in this regard. The purpose of this study was to identify and rank important indicators in the performance of health, safety, environment, and energy education. Materials and Methods: The present study was designed and implemented based on four steps. In the first step, the literature was studied, and the functional indicators of education were identified. The reliability and validity of the tool were examined under the supervision of a panel of experts. In the third step, the appropriate criteria for ranking key performance indicators of health, safety, environment, and energy (HSEE) education were selected using the present literature. Moreover, in the next step, the experts were provided with a checklist, including 43 key performance indicators for HSEE education based on smart metrics. Then the data were analyzed by combining the hierarchical analysis and Fuzzy TOPSIS. Results: According to the obtained results, the highest weight related to the specificity criterion was reported as 0. 34. The highest relative importance of the indicators was related to holding HSEE courses in the form of the workshop (CCI: 0. 516), running HSEE courses electronically (CCI: 0. 508), participating level of individuals in training (CCI: 0. 505), which were ranked one to three. Conclusion: The implementation of selected indicators with regard to the sensitivity and effective role of education in improving health, safety, and environmental management systems are the necessities of using these indicators, along with other indicators of this system.

Background and Objective: Effective communication is an important factor in pre-hospital care. The emergency medical communication and dispatch center is one of the most stressful work environments in the healthcare domain so that it is essential to assess the harmful factors associated with this work environment. According to the guidelines of prehospital emergency procedures, it should take 120 seconds from the triage nurse response to the moment the mission is announced. The present study aimed to investigate the effect of ergonomic status at the workplace on the time of the announcement of the mission to dispatch personnel working at emergency medical communication and dispatch center. Materials and Methods: This study was conducted based on a descriptiveinterventional design. In total, 36 participants were randomly selected from emergency medical communication and dispatch center. The data were collected using luxmeter, sound meter, and rapid office strain assessment. This study evaluated the time of the mission announcement by the communication and dispatch staff. The data were analyzed through descriptive statistics. P-value less than 0. 05 was considered statistically significant. Results: According to the results, the intervention affected the time of call registration and the mission assignment. The measured time before the intervention was 2. 02s which decreased to 1. 92s after the intervention. Therefore, the results indicated that the intervention significantly contributed to the differences between the times of registration until the mission assignment. Conclusion: It can be concluded that the improvement of ergonomic status can have effects on the staffs' performance.

Background and Objective: In many countries, the noise has been ranked among the important risk factors in the printing industries. The purpose of this study was to design a tool for assessing the level of knowledge, attitude, and practice of the printing industry workers in terms of hearing protection and determine its validity and reliability. Materials and Methods: To design a questionnaire, 35 questions were provided as the first step. Content validity methods were utilized in order to evaluate the validity of the questionnaire. Moreover, Cronbach's alpha coefficient and test-retest methods were used to assess the reliability of the questionnaire. The data were analyzed using SPSS software (version 20). Results: The obtained results showed that 10 items in terms of content validity were below the standard levels and should be removed from the questionnaire. In addition, in the reliability analysis of the questionnaire, Cronbach's alpha coefficients were reported as 0. 884, 0. 719, 0. 832, and 0. 727 for all four parts of knowledge, attitude, risk perception, and practice, respectively. The Spearman’ s correlation coefficients with the results of 0. 810, 0. 861, 0. 890, and 0. 985, as well as Pearson correlation coefficients with the results of 0. 912, 0. 964, 0. 866, and 0. 991, were used for knowledge, attitude, risk perception, and practice, respectively, to analyze the test-retest method of the questionnaire. Conclusion: Designing this questionnaire to investigate the knowledge, attitude, and practice of the printing industry workers regarding hearing protection can examine possible solutions to reduce the harmful effects of the noise on employed workers, which is recommended to be tested on a larger scale.

Background and Objective: Despite the advances in occupational safety, many accidents still occur in the workplace, most of which are due to the poor safety performance of the workers. The knowledge of the factors affecting safety performance is a suitable guide regarding the plan developments for occupational accident prevention. Therefore, this study was conducted to measure and determine demographic factors affecting the safety performance of workers Materials and Methods: This cross-sectional and analytical study was carried out on 487 workers working at a gas refinery in 2018. The Persian version of the Neal and Griffin questionnaires were used in order to measure their safety performance. Moreover, demographic characteristics were measured by a researcher-made questionnaire. Psychometric properties of this questionnaire were initially measured to ensure the validity and reliability of the safety performance questionnaire. In addition, the relationship between demographic characteristics and safety performance was assessed using SPSS software (version 23) through one-way ANOVA and independent sample t-test. Results: The primary results of this study showed that the safety performance questionnaire had desirable validity and reliability. Moreover, the safety performance of workers was at the desired level. According to the results obtained from the demographic characteristics, safety performance was correlated significantly with age and job experience (P<0. 05). In other words, low experienced and younger workers had a poor safety performance, compared to the elderly ones. Conclusion: Considering the poor safety performance of young and low experienced workers, compared to the older and high experience ones, it is necessary to pay more attention to these two groups in the development of safety plans in the workplace.

Background and Objective: Heat stress is one of the major occupational problems in Iranshahr, Iran, which has led to adverse effects on the health and productivity of individuals. This study aimed to examine this problem and its effects in different departments of Iran Hospitals in Iranshahr. Materials and Methods: This cross-sectional study was performed from 9 am. to 12 pm on 118 employees working at different departments of a hospital. Wet-bulb globe temperature (WBGT) and discomfort index (DI) were used to measure heat stress and thermal discomfort. Moreover, to assess human resource productivity, a 26-item scale of human productivity developed by Hersey and Goldsmith was utilized in this study. In addition, the relationship between WBGT and DI indices with human productivity and its micro-scale components was investigated using Pearson correlation coefficient. Results: The results showed that at 9 am. the highest mean values regarding WBGT and DI indices were allocated to installation powerhouse 1 and generator 2 units, respectively. Additionally, pharmacy and administrative units obtained the lowest values in terms of the mentioned indices. At 12 pm, the highest mean values regarding WBGT and DI indices were allocated to powerhouse 2 and generator 2 units, respectively. At the same time, neonatal intensive care unit and the pharmacy obtained the lowest values of these indices, respectively. Furthermore, the results of the Pearson correlation coefficient showed a reverse and significant relationship between WBGT and DI indices with human productivity (P<0. 05). Conclusion: Based on the results of this study, the higher rate of heat stress in this hospital reduced the levels of human productivity and efficiency. Therefore, it is essential to design and repair the ventilation systems in this hospital to provide suitable thermal conditions in accordance with international standards which lead to the heat stress reduction and human productivity and efficiency increase.