In 2011, load limits for manual lifting were adopted in Iran to protect workers from low back injury without prior testing of accuracy with Iranian workers. This investigation examined how accurate the adopted ACGIH TLVs at the allowable limits predict risk for LBP disorders for a group of Iranian workers using biomechanical criteria. Testing took place in the laboratory with participants completing a series of 2-handed lifting tasks as defined in the Iranian Guideline for Manual Lifting. To test accuracy, both compression and shear forces were estimated for fifteen male Iranian workers who completed 25 lift combinations that varied in height and reach with the maximal allowable load. The findings, when compared to a risk threshold of 3400 N compression and 700 N shear, showed above-threshold forces for compression and little-to-no safety margins with repetitive lifting for most lifts at torso height and below. Since Government, employers and workers use these guidelines to decide on work/workplace design; these guidelines require further review and revision based on the anthropometrics of Iranian people.
Background: Manual handling may cause workers to deal with various risk factors. Workers performing such tasks repeatedly for a long time are more prone to bodily injuries and physical problems such as back pain. Objectives: The current study aimed to assess the compressive loads estimation and analysis of forces exerted on the workers' back in manual load lifting tasks using the national institute for occupational safety and health (NIOSH) equation and compare them with the recommended weight limit (RWL). Methods: It was a cross-sectional study in a laboratory setting on 15 healthy male workers in 2015. The participants were required to randomly perform 25 tasks with four iterations. The lifting index (LI) was calculated by NIOSH equation in simple tasks and compressive loads on the low back (L4/L5) for each task were calculated using the 3DSSPP. Data were analyzed using SPSS version 16. Results:The results showed that the highest compressive force exerted on the back was equal to 4002 N and the lowest force 1425 N. Moreover, 76% of the tasks were reported to have the highest compressive force greater than the recommended limit; 72% of the tasks had an LI 1 -3 and 28% of them had an LI less than 1. There was a weak direct correlation between compressive force and RWL. Conclusions: The NIOSH equation and compressive force estimation function were partially similar to identify high-risk tasks, however, by the compressive force estimation, biomechanical analysis of tasks can be done better since it is quantitative and can determine the exact amount of forces exerted on the back.
Background:The light is one of the electromagnetic waves that can be created from conversion of electrical energy into a visible energy for human eye. The illumination intensity is measured in order to compare with the quality standards of light and for estimation of energy waste and lighting system performance. Therefore, the systematic and scientific measurement principles in data validation are very important. Objectives: The purpose of this study was to measure the actual artificial lighting by various valid procedures. Materials and Methods: The overall, artificial and natural lighting has been measured at different times and in rooms with open and closed blinds mode and based on the various measuring stations. Results:The results show the artificial lighting obtained by difference methods of the overall lighting from natural lighting in closed blinds mode equal to 266 Lux and night lighting 283.5 Lux that they have no significant differences with each other (P = 0.269). As well as the illumination intensity obtained from a standard grid method is 283.5 Lux and illumination intensity based on Luminaires layout model is 274 Lux with no significant difference (P = 0.269) Conclusions: The present study shows that method of difference (subtracting the overall light from natural light) can be a good option to measure the illumination intensity of artificial lighting system in any state (open or closed curtains) and time of the day and a standard method for measuring the lighting per residential, administrative and training units.
Introduction: Manual Material handling includes activities in which pushing, pulling, lifting, lowering, carrying, and holding the load, the most common of which is lifting. This study aimed to evaluate the reliability of the KIM-LHC method to identify high-risk manual load lifting tasks. Material and Methods: This cross-sectional study was performed on healthy male workers with a history of manual material handling in a laboratory setting. The sample size was determined according to previous studies of 15 people. The participants were required to perform 25 tasks with four iterations randomly. An inclinometer device was used to determine the forward bending angle at the waist. Compression loads exerted on L5/S1 were estimated using 3DSSPP software using participants' postural and anthropometric information. Also, the tasks were evaluated using the KIM-LHC method, and their final scores and levels of MSD risks were determined. Data were analyzed using SPSS.20 software and the Chi-square test. Results: The results of compression load estimation for lifting tasks showed that 92% of the tasks had a low-risk level (less than 3400 N), and 8% of the tasks had a medium-risk level (3400 to 6800 N). While the results of the KIM-LHC method showed that 28% of tasks had a low-risk level, 64% had a medium level, and 8% had a high-risk level. Conclusion: The results of this study showed no correlation between the risk levels of the KIM-LHC method and the estimated compression load for some designed lifting tasks. Therefore, there is a possibility of error in estimating the risk level of some lifting tasks by the KIM-LHC method, and more biomechanical studies should be performed on kinetics and kinematics.
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