مجله مهندسی بهداشت حرفه ای
سال هشتم شماره 3 (پاییز 1400)

Grip strength is one of the important parameters in hand muscle function that vibration can have a negative effect on it. The aim of this study was to determine of the sport intervention effect on the grip strength of workers exposed to hand-arm vibration.

In this descriptive-interventional study, 41 workers were studied in one of the metal industries in Isfahan. Data were collected using demographic questionnaires, hand-arm vibration acceleration was measured according to ISO 5349 and grip strength was measured with a Jamar dynamometer. The intervention of hand sport movement was performed after measuring the workerschr('39') strength grip for 8 weeks. Data were analyzed using SPSS-21 software. 

Workerschr('39') grip strength was significant before and after exposure to vibration (PValue <0.001). The grip strength average of workers before work with vibrating tool was 42.16±3.8 kg force and after the end of work shift and finishing work with vibrating tool was 39.55±3.97 kg force. Amounts differences of grip strength were obtained significant before the intervention execution of hand sport movements with grip strength after intervention execution (Pvalue <0.001).

The results of this study showed, vibration reduced the grip strength of workers; while doing intervention of hand sport movements was effective in improving the workers grip strength. Therefore, performing sports movements effectively and efficiently leads to improving the grip strength of workers exposed to vibration.

The extent and variety of chemicals in the used compounds in nail salons can cause irreparable damage 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 study of occupational symptoms caused by exposure to chemical compounds in nail salons in Tehran.

To design the Questionnaire, by the thoughts of the expert  questions were designed and validated. Then it was provided to the employees. Finally, the data were analyzed in SPSS software (version 20).

In this study, the total values of CVI and CVR were calculated to be 0.79 and 0.86, respectively. in the  reliability section, ICC correlation coefficient in test-retest in the dimensions of workplace information, personal characteristics and habits, information and knowledge of using the materials, skin, eye and respiratory symptoms (cough, bronchitis, shortness of breath and wheezing) were obtained 1.00, 0.98, 0.99, 1.00, 0.80 and (1.00, 1.00, 0.94), respectively. Cronbach’s alpha coefficient was higher than 0.70 for all dimensions, which is acceptable; And the most common symptoms among employees was sneezing and itching skin lesions.

The results indicated that the questionnaire has good validity and reliability for assessing occupational symptoms due to exposure to chemical compounds in nail salons.

Fire outbreaks in buildings have diverse negative consequences for the occupants’ life safety, assets, etc. Determining the level of fire safety will help to provide appropriate solutions to increase fire safety, thus reducing fire consequences. Therefore, the aim of this study was to analyze the level of fire safety in office buildings.

This research was an analytical-descriptive study conducted with the aim of analyzing 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. The study was conducted as per the Fire Safety Evaluation System (FSES) methodology and NFPA 101A.

According to the results, the fire control aspect was revealed to have the best condition in all seven buildings under study and they obtained the required scores. Egress routes had the worst condition. In the aspect of general fire safety, all selected buildings, except one building, maintained the required requirements.

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 improving the general fire safety. Installing a quick-response automatic sprinkler system with an entire building coverage, would enhance the overall fire safety condition in the buildings. Also, considering smoke control systems could make the condition of the buildings better in terms of egress routes and general fire safety.

Workers in many industries (oil, gas, petrochemicals, cement, steel, glass, and textile) and even at home, offices are exposed to various noises with different frequencies causing hearing and non-hearing impairments. The present study aimed to investigate the effect of noise at different frequencies on physiological responses and cognitive functions of oil drilling industry personnel and urban gas pressure reducing station.

This descriptive-analytical study was conducted in 2019 with the participation of 50 employees of oil drilling rigs (low frequency noise) and city gas pressure reducing stations (high frequency noise). Physiological parameters examined included (heart rate, systolic and diastolic blood pressure, and tympanic body temperature). The participantschr cognitive functions were assessed using advanced reaction timer, continuous performance and working memory tests before, during and after the activities. Also, the relationship between variables was investigated using structural equation modeling (SEM).

The study results indicated that was exposed to noise at high and low frequencies, physiological responses, including heart rate, systolic and diastolic blood pressure and tympanic temperature increase, and this increase was statistically significant (p <0.001). Exposure to noise also has a negative effect on cognitive functions (such as working memory, sustained attention, and advanced reaction timer).

Low frequency noise has a greater effect on physiological responses and cognitive function than high frequency noise. Obviously, further research in this area is suggested in the industry.

Electricity-related occupational accidents are the fifth leading cause of occupational deaths. One of the major causes of occupational accidents is human error. That is why the human role as a cause of the accident is so important and must be considered during risk assessment. The purpose of this study is to present a Fuzzy-HERAT human error assessment method, which can be used to assess the probability of human error in the job of securing the electrical network using the expertschr('39') opinions. Tasks of the power distribution system were first analyzed using the HTA method and in the next step, the probability of the general error of that task was determined, and then the error producing conditions for each task were determined. In the next step, the linguistic terms of the relevant experts on each EPC was obtained and finally these linguistic terms were quantified using the fuzzy method and then the probability of total human error for each task was calculated. Finally, tasks were prioritized based on the probability of human error. Using HTA technique, it was found that the safety operation of power grids consists of 5 main tasks. With the Fuzzy-Heart technique, the task of interrupting the power supply was the most likely to cause human error. The results showed that the proposed Fuzzy-Heart technique has been successfully applied in estimating the probability of human error. The proposed method can identify the conditions that cause the error and estimate the impact contribution to each of these conditions.

Noise is a kind of mechanical energy that is sensed by the human hearing system. It can cause physiological and psychological disturbances, therefore controlling the exposure to this harmful factor is highly important in industrial and non-industrial workplaces. The purpose of this study is to determine the effectiveness of acoustic barriers on noise reduction in one generator building.

 This case study carried out four stages in January 2020, which including: determining the purpose of the measurement, gathering information from the location, selecting the proper material, designing, installing the noise barrier, and evaluating its effectiveness. The environment noise level was measured according to ISO 9612-2009 [E] by the Casella CEL Model 450 sound level meter.

The average noise reduction, 1 m from the noise barrier was 19.5 dB, the highest transmission loss recorded was 22.4 dB.at 8000 Hz.

Due to the simplicity of the design, the ease of implementation, and the efficiency of the sound barrier introduced in this project is recommended for similar conditions with an effectiveness of 19±0.5 dB.

Date palm is the second most important agricultural crop of Iran after pistachio. Traditionally, the nature of work for palm farmers requires physical work, including the undesirable and long-term postures when working on the tree. This study aimed to investigate the ergonomic conditions and the relationship between the severity of discomfort and working postures in date palm farmers. 

This cross-sectional study was carried out on 100 skilled date palm farmers who were engaged in date cultivation during 2020. To investigate the ergonomic conditions and the relationship between the severity of discomfort in the farmers, the REBA and the Body Part Discomfort Rate )BPDR) methods were used. The data of farmers while working on palm trees by traditional tools was recorded, and the data were analyzed by SPSS Ver.26 software. 

The results of the present study showed that the most musculoskeletal discomfort was in the upper arm, legs, and trunk. According to the tasks analysis, in most of the farmerschr('39') tasks, there was a significant relationship between awkward postures and the severity of discomfort in different body regions (p <0.05). 

Upper arm, legs, and trunk are most exposed to musculoskeletal disorders among date farmers. Also the "harvesting" and "climbing/descending" tasks can be considered as high-risk operations in terms of musculoskeletal disorders and therefore, using mechanical tools to perform operations on palms can play an important role in reducing the risk of musculoskeletal disorders in date farmers.

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 was aimed to fabricate nonwoven nanofiber media with antibacterial activity using electrospinning process.

Polyurethane-chitosan nanofiber media with weight ratios of 100 to 0, 90 to 10, 80 to 20, and 70 to 30 were fabricated by simultaneous electrospinning process. After preparation of the nanofiber media, their antibacterial properties were evaluated by standard methods of disk diffusion (ISO 20645) and colony counting (ISO 20743).

The bacterial growth inhibition zones gradually are formed around the examined samples by adding the layers of chitosan nanofibers to the polyurethane media indicating the antibacterial activity of these substrates. The evaluation 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 value of bacterial growth inhibition zone and antibacterial activity for polyurethane-chitosan (70/30) media were 0.226 mm and 2.222, respectively.

Evaluating the antibacterial activity of prepared nanofiber media indicated that antibacterial nanofiber media can be created by adding chitosan nanofibers as antimicrobial agents to the polyurethane nanofiber.