Journal of Occupational Hygiene Engineering
Year:2021 | Volume:8 | Issue:3|Papers Count:8

Background and Objective: Grip strength is one of the important parameters in hand muscle function that can be negatively affected by vibration. This study aimed to determine the effect of sport intervention on the grip strength of workers exposed to hand-arm vibration. Materials and Methods: This descriptive-interventional study was conducted on the workers (n=41) of one of the metal industries in Isfahan, Iran. The required data were collected through the completion of demographic questionnaires, measurement of hand-arm vibration acceleration based on ISO 5349, and assessment of grip strength with a Jamar dynamometer. The intervention of hand sports movement was performed for 8 weeks. The gathered data were analyzed in SPSS-21 software. Results: The grip strength of the workers was significant before and after exposure to vibration (P<0. 001). The mean scores of workers' grip strength were obtained at 42. 16± 3. 8 and 39. 55± 3. 97 kg force before working with the vibrating tool and after the end of the work shift and finishing working with the vibrating tool, respectively. The difference between grip strength before and after the intervention of hand sports movements was significant (P<0. 001). Conclusion: The results of this study showed that vibration reduced the grip strength of workers; while performing the intervention of hand sports movements was effective in improving the workers' grip strength. Therefore, sports movements could effectively and efficiently improve the grip strength of workers exposed to vibration.

Background and Objective: The extent and variety of chemicals in the compounds employed in nail salons can cause irreparable damages to the health of nail technicians. Because of the lack of attention to health risks in this industry compared to other industries, the present study was conducted to design a tool for a preliminary investigation of occupational symptoms caused by exposure to chemical compounds in nail salons in Tehran, Iran. Materials and Methods: A questionnaire was designed and validated by reviewing the literature and the opinions of experts in developing questions. The questionnaire was then distributed among the nail technicians, and finally, the data were analyzed in SPSS software (version 20). Results: In this study, the total values of content validity index and content validity ratio were calculated at 0. 79 and 0. 86, respectively. Regarding the reliability of the instrument, intraclass correlation coefficients in test-retest were estimated at 1. 00, 0. 98, 0. 99, 1. 00, 0. 80, and (1. 00, 1. 00, 0. 94), respectively for the dimensions of workplace information, personal characteristics and habits, information and knowledge of the used materials, and skin, eye, and respiratory symptoms (e. g., cough, bronchitis, breath shortness, and wheezing). Cronbach’ s alpha coefficient was higher than 0. 70 for all dimensions, which was acceptable. The most common symptoms among the subjects were reported to be sneezing and itching skin lesions. Conclusion: The results indicated that the questionnaire had good validity and reliability for assessing occupational symptoms due to exposure to chemical compounds in nail salons.

Background and Objective: Fire outbreaks in buildings have diverse negative consequences for the occupants’ life safety and assets. Determining the level of fire safety is of great help in the provision of appropriate solutions to increase fire safety and reduce the negative consequences. Therefore, the present study aimed to analyze the level of fire safety in office buildings. Materials and Methods: This analytical-descriptive study was conducted to analyze the fire safety level in office buildings of a car manufacturing company on the basis of three aspects: fire control, egress routes, and general fire safety. This study was performed using Fire Safety Evaluation System (FSES) methodology and NFPA 101A. Results: Based on the results, the fire control aspect was revealed to have the best condition in all seven buildings under the study, and they obtained the required scores in this regard. On the other hand, egress routes had the worst condition. In terms of general fire safety, all the selected buildings, except one building, maintained the required requirements. Conclusion: As evidenced by the obtained results, conducting more than two fire exit drills per year would make the condition of the selected buildings acceptable in the aspect of egress routes. It could also have a significant effect on the improvement of general fire safety. Moreover, installing a quick-response automatic sprinkler system with entire building coverage would enhance the overall fire safety condition in buildings. Furthermore, considering smoke control systems could make the condition of the buildings better in terms of egress routes and general fire safety.

Background and Objective: Workers in many industries, such as oil, gas, petrochemicals, cement, steel, glass, and textile, as well as people at home and offices, are exposed to various noises with different frequencies, causing hearing and non-hearing impairments. The present study aimed to assess the effect of noise at different frequencies on physiological responses and cognitive functions of the personnel working in the oil drilling industry and urban gas pressure reducing stations. Materials and Methods: This descriptive-analytical study was conducted on 50 employees of oil drilling rigs (low-frequency noise) and urban gas pressure reducing stations (high-frequency noise) in 2019. The examined physiological parameters included heart rate, systolic and diastolic blood pressure, as well as tympanic body temperature. The participants' cognitive functions were assessed using an advanced reaction timer, continuous performance, and working memory tests before, during and, after the activities. Results: Based on the obtained results, exposure to noise at high and low frequencies increased physiological responses, including heart rate, systolic and diastolic blood pressure, and tympanic temperature, and this increase was statistically significant (P<0. 001). Moreover, exposure to noise has a negative effect on cognitive functions (such as working memory, sustained attention, and advanced reaction timer). Conclusion: As evidenced by the results of the present study, low-frequency noise had a greater effect on physiological responses and cognitive function, as compared to high-frequency noise. Nonetheless, further research is suggested to be conducted in the industry in this area in the future.

Background and Objective: Electricity-related occupational accidents are the fifth leading cause of occupational death. One of the major causes of occupational accidents is human error; therefore, the human role as a cause of the accident is highly important and needs to be considered in risk assessment. This study aimed to present a Fuzzy-Human error assessment and reduction technique (HERAT) technique, which can be used to estimate human error probability in the job of securing the electrical network using the experts' opinions. Materials and Methods: First, the tasks in the power distribution system were analyzed using the HTA(Hierarchical Task Analysis) method. In the next step, the general error probability of each task was determined, and then, the error-causing conditions for each task were determined. Afterward, the linguistic terms of the relevant experts on each error-producing condition were obtained, and then, these linguistic terms were quantified using the fuzzy method and the probability of total human error for each task was calculated. Finally, tasks were prioritized based on human error probability. Results: The employment of the HTA technique led to the finding that the operation of securing power grids consisted of five main tasks. The most likely human error was found to be the task of interrupting the power supply, which was revealed using the Fuzzy-HEART technique. Conclusion: The results showed that the proposed Fuzzy-HEART technique has been successfully applied in estimating the human error probability. The proposed method could identify the error-causing conditions and estimate the impact contribution to each of these conditions.

Background and Objective: Noise is a kind of mechanical energy that is sensed by the human auditory system. It can cause physiological and psychological disturbances, therefore controlling the exposure to this harmful factor is highly important in industrial and non-industrial work environments. The present study aimed to determine the effectiveness of acoustic barriers on noise reduction in one generator building. Materials and Methods: This case study was conducted in four stages in January 2020, which included: determining the purpose of the measurement, gathering information from the site, selecting the proper material, designing, installing the noise barrier, and evaluating its effectiveness. The level of environmental noise was measured according to ISO 9612-2009 [E] using Casella CEL-450 Sound Level Meter. Results: The average noise reduction, 1 m from the noise barrier was 19. 5 dB, the highest recorded transmission loss was 22. 4 dB. at 8000 Hz. Conclusion: The sound barrier introduced in this project is recommended for similar conditions with effectiveness of 19± 0. 5 dB due to the simplicity of the design, ease of implementation, and efficiency.

Background and Objective: Date palm is the second most important agricultural product in Iran after pistachio. Traditionally, working as a palm farmer requires severe physical work, including the inconvenient and prolonged posture of working on the tree. The present study aimed to investigate the ergonomic conditions and the relationship between the severity of discomfort and working postures among date palm farmers. Materials and Methods: This cross-sectional study was conducted on 100 skilled date palm farmers who were engaged in date cultivation during 2020. REBA and the Body Part Discomfort Rating (BPDR) methods were used to investigate the ergonomic conditions and the relationship between the severity of discomfort in the farmers. The data of farmers was recorded while working on palm trees with traditional tools, and the data were analyzed using SPSS software (Version 26). Results: The results of the present study indicated that the most musculoskeletal pain was in the upper arm, legs, and trunk. According to the task analysis, there was a significant relationship between inappropriate postures and the severity of discomfort in different regions of the body (p <0. 05). Conclusion: Upper arms, legs, and trunk are more exposed to musculoskeletal disorders among date farmers. Also, harvesting, pruning, climbing, and descending palm trees can be considered as high-risk tasks in terms of musculoskeletal disorders. Therefore, using mechanical tools to perform operations on palms can play a substantial role in reducing the risk of musculoskeletal disorders in date farmers.

Background and Objective: The accumulation of airborne bioaerosols on filtration media and their gradual proliferation in the presence of appropriate moisture and environmental conditions is one of the major problems against using these media. The use of hybrid media containing antibacterial agents is one of the available solutions to this problem. The present study aimed to fabricate nonwoven nanofiber media with an antibacterial activity using an electrospinning process. Materials and Methods: Polyurethane-chitosan nanofiber media the weight ratios of 100 to 0, 90 to 10, 80 to 20, and 70 to 30 were fabricated by simultaneous electrospinning process. The evaluation of the antibacterial properties of the media was performed after their preparation by standard methods of disk diffusion (ISO 20645) and colony counting (ISO 20743). Results: The investigation of antibacterial activity of samples by both methods showed that the media with polyurethane to chitosan weight ratio of 70 to 30 had suitable antibacterial activity. The mean values of bacterial growth inhibition zone and antibacterial activity for polyurethane-chitosan (70/30) media were obtained at 0. 26 and 2. 225 mm, respectively, indicating the significant antibacterial activity of this media. Conclusion: The results showed that antibacterial nanofiber media can be created by adding chitosan nanofibers as antimicrobial agents to the polyurethane nanofiber.