Journal of Health and Safety at Work

Introduction: In last decades, due to the increase in the number of VDT works prevalence of musculoskeletal disorders has increased among users. One of the main risk factors for those problems might be related to the computer keyboards. Keyboards might lead to these problems, in different ways. Keyboard geometry is one of the main ways. As a result, the various types and shapes of personal computer keyboards have designed in order to provide a neutral or relaxed posture in the wrist and forearm areas. Slanted, sloped and tilted keyboards are the most important alternative keyboard designs for this mean.

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Material and Method: In this paper, with a systematic approach, related studies were searched in authentic databases and finally eleven studies met to our inclusion criteria for review.

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Result: findings in different studies showed that alternative keyboards clearly can provide an ergonomic neutral posture for the wrist and forearm. As a specific objective in the study, it was found that the best keyboard, to form an ideal posture for the wrist and forearm is ‘NIOSH keyboard‘ because of its ergonomic design.

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Conclusion: Considering the positive effect of the alternative keyboards on the wrist and forearm postures, it is concluded that use of the alternative keyboards can decrease risk factors related to the wrist and forearm postures. Results can be applied by personal computer users, computer designers, occupational hygienists and ergonomists.

Introduction: Job design approach is one of the significant concepts in ergonomics Experts believe that integration of macro ergonomics and job design can lead to improved productivity in the organizations. Therefore, this study examined the relationships between job design, performance and job satisfaction.

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Methods and Materials: This cross - sectional study was done in 11 branches of one of the bank in Hamadan. Job Design Questionnaire, Job Satisfaction Questionnaires and Bank Performance Indicator were used in order to collect data. spearman correlation coefficient was used for determining the correlation between each two variables.

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Results: This study showed that the motivational approach was the minimum approach (3.8%), and the mechanical approach, was the dominant approach (74.7%) in the study branches and the majority of branches had an average level of job satisfaction. Moreover, there was a significant positive correlation between job design (motivational and cognitive approaches) and job satisfaction. In addition, the results showed that between job design (Motivational approach) and satisfaction were significantly correlated with performance, (p = 0.05).

Conclusion: Regarding the role of job design in job satisfaction and employees, performance, it can be stated that job redesign towards a motivational approach and considering the principles of ergonomics in the workplace, can play an important role in efficiency and productivity of an organization.

Introduction: Children have been known to spend most of their time at school. They learn their sitting habits in this period of time. Incorrect sitting postures and inappropriate school furniture can result in abnormalities in the vertebral column, back pain, neck pain, Fatigue and discomfort. Hence, this study was aimed to examine the match between students’ body dimensions and existing benches and desks dimensions in Hamadan female primary schools.

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Material and Method: In this study, 624 students of Hamadan female primary schools were investigated and some of their anthropometric dimensions including shoulder height, elbow height, knee height, popliteal height, popliteal-buttock length and hip breadth were measured. In this sense, a chair (with adjustable height, depth and elbow support) and a caliper with movable jaw were used for measurement of anthropometric dimensions. The measurements were performed in a way that thighs were in full contact with the seat, there was a right angle between the thighs and legs, the feet were in full contact with the movable pedal, the trunk was straight and the back and hips were in full contact with the backrest. Following, the match of the dimensions of existing benches and desks with the appropriate dimensions (based on the students’ anthropometric dimensions) were examined.

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Result: The results showed that the seat height, seat depth, seat width, back rest height, desk height, underneath desk height were in acceptable rangefor 10.1%, 17.3%, 5.6%, 53.5%, 1.9% and 31.1% of students, respectively.

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Conclusion: Despite differences in the body dimensions of primary school students, there is no regularity in using of school furniture. Overall, the dimensions of existing benches and desks are not matched with the anthropometric dimensions of students.

Introduction: Workplace design is one of the factors that can influence comfort, performance, productivity and the health status of employees. The effects of this factor on human’s productivity and performance are studied in the domain of ergonomics. The impact of workplace design on workers’ productivity and performance can be determined by investigation of the quality of the design. The main purpose of the present study was to investigate the influence of workplace design on productivity of the bank clerks.

Material and Method: Samples in this cross-sectional study were comprised of 150 employees of 22 different branches of a bank in Tehran city. Data collection tools included demographic questionnaire and a questionnaire related to the effects of workplace design on employees’ productivity, developed by Hameed and colleagues. Correlation and regression statistical tests were used in order to analyze data.

Result: According to the results, the mean (±SD) for age and job tenure of participants were 37.2(±6) and 13(±7) years, respectively. Of the surveyed demographic features, a significant relationship was observed between age and scores belonging to the temperature and furniture (P-value<0.05). In addition, there was a significant association between employees’ productivity and the noise (P-value=0.044) and spatial arrangement of environment (P-value=0.048).

Conclusion: Overall, appropriate and high quality design of work environment can improve productivity of bank clerks. In other words, employees’ productivity can be enhanced by comfortable and ergonomic design of working environment and also by considering their needs.

Introduction: Application of inherently safety principle in the early phase of the design process is very efficient, as this approach is an economic and high efficiency method. While a complete information is not available in the initial phases of the process, the use of valid index to evaluate inherently safety can be efficient. In this case, the best route to design safer process can be selected by comparing the quantitative results.

Material and Method: The comprehensive index to evaluate the inherently safety design (ISD) and cost evaluation of the implementing inherently safety design (ISDC) were studied using a three-step hierarchical matrix screening in this research. Utilizing the proposed inherently safety index, Acetic acid production process and cost resulting from ISD were evaluated. Dimensions of the Matrix for ISD and ISDC included: 1) quadrature inherently safety design vector, 2) location vector of inherently safety design and 3) quantity parameter vector of inherently safety design.

Result: In order to optimize the implementation of inherently safety design and its cost, three hypotheses were used. From them, the idea of using two processes with half capacity and also using 50% Methanol were selected as a design with the highest level of inherently safety and a design with the lowest-cost process, respectively.

Conclusion: In these evalustions the total score for the assumptions of the inherently safety index 1, 2 and 3, were 55,70 and 135, respectively. And the total cost assumptions 1, 2 and 3, have been estimated 858,000, 746,000 and 803,000 US dollars, respectively. Therefore, this tool could show the impact of various scenarios in inherently safety design and also the contrast between the four principles of ISD and its impact on safety and cost factors can be analyzed using an alternative system supplier of methanol.

Introduction: Nursing is one of professions that employees are at risk of fatigue and work related musculoskeletal disorders, because of high physical workload and high job stress. Connecting serum set to serum solution is one of the repetitive tasks for nurses in their working times and it may cause pain and discomfort in their hand. The aim of this study was to design and ergonomic evaluation of a tool for connecting serum set to serum solution.

Material and Method: This experimental- interventional study conducted on 12 nurses (6 men and 6 women) in 3 phases. First phase was assessment of manual connecting of serum set to the bag by nurses, second phase was design and manufacturing of serum set connector and third was ergonomic assessment of the manufactured tool. In first and third phases, amount of perceived exertion by nurses was assessed using the Burg scale (CR10), and electromyography assessment for hand muscles activity was conducted during connecting serum set. Data of first and third phases compared with statistical tests.

Result: Mean score of perceived effort during manual connection of serum set was 5±1/2 (of 10) and while mechanical connection with designed tool was 2.3±0/49. There was significant difference between activity in 5 muscles (Flexor Digit Comonis, Flexor Carpi Radial, Biceps, Triceps and Deltoid) in manually and mechanically connection mode (P-value<0.05).

Conclusion: Use of serum set connector reduced the perceived effort and activity of hand and wrist muscles. This device can be used as an ergonomic tool for nurses to easing the inserting the serum set to serum solution