Virtual modelling and analysis of manual material handling activities among warehouse workers in the construction industry.

BACKGROUND: Musculoskeletal risks (MSRs) are a major concern among construction warehouse workers due to the lifting, carrying and lowering of heavy loads. OBJECTIVE: The objective of this study was to reduce MSRs among warehouse workers in the construction industry using virtual modelling and analysis of activities. METHODS: A preliminary study was carried out using the Standard Nordic Questionnaire. Biomechanical analysis, Ovako Working posture Assessment System (OWAS) and Rapid Upper Limb Assessment (RULA) were used to analyse the material handling activities. Virtual modelling was used develop the manikins with autoclaved aerated concrete (AAC) blocks at different carriage modes and stacking heights for the analysis. RESULTS: The preliminary study results revealed a higher prevalence of risk at their lower back (73.24%) among the construction warehouse workers. Biomechanical analysis showed a higher risk at L4-L5 joint of lumbar spine during overhead and bending postures for stacking the blocks. Posture analysis results of OWAS indicated a lower risk in overhead carriage mode. Detailed analysis with RULA confirms this result. Mean compressive force values at stacking heights were showed a significant difference (p < 0.05) in 8, 13, 18 and 21 kg AAC blocks. However, stacking height with a range of 120-140 cm was found as safer to the workers by considering all block sizes. CONCLUSION: An ergonomic intervention based on safer stacking heights was developed to reduce MSRs to an acceptable range. It improves productivity of handling the AAC blocks by reducing the cycle time. The intervention can be adapted for handling of similar materials in the construction industry.

Virtual postural assessment of an assembly work in a small scale submersible pump manufacturing industry.

BACKGROUND: Depletion of groundwater has increased the depth of bore wells drilled to meet water requirements. Water from these bore wells are accessed by operating submersible pumps with multi-stages. The number of stages of submersible pump directly depends upon the depth of bore well. Health-related risk such as Musculoskeletal Disorders (MSDs) arises during the manual assembly of these pumps in an awkward posture. OBJECTIVE: The objective of this paper is to eliminate or reduce risk in the manual assembly of submersible pumps using virtual postural analysis. Secondary objective is to redesign the existing workstation incorporating ergonomic interventions. METHODS: It reports a case study in which postural analysis is carried out with the help of Rapid Upper Limb Assessment (RULA) method. RESULTS: It is observed that inserting the stage casing weighing around 1.5 Kg through top end of the shaft is the awkward working posture involving a flexion of the arm about 152°. RULA score (7) indicate a high level of risk exists in the workstation, calling for investigate and change the working posture immediately. In order to reduce this risk, a redesigned workstation has been proposed. CONCLUSION: This study results help in minimizing the awkward postures, thereby reducing the health-related risk. This will also increase the efficiency of the worker and his productivity.