Evaluation of ergonomic risk factors by OCRA method in assembly industry

Abstract

Background and aims: In order to assess specific factors There are several risk assessmentmethods including occupational repetitive action (OCRA) which is used in industries withrepetitive motion, increased force, awkward posture, and lack of recovery periods.These riskfactors exists in assembly lines, and the purpose of this investigation is assessment of ergonomicrisk factors by OCRA method in assembly lines.Methods: Job analysis was done by observation and each job was degraded to tasks, actionsand movements. Nordic standard questionnaire (NMQ) was used for demographic data andupper limbs MSD complaints in 10 factories. Two assembly lines were assessed and 166 OCRAindices were obtained and analyzed with OCRA software and SPSS software using chi-squareand paired t- test.Results: The results showed that in line B the highest risk in right hand was 66% (low risk), andin line Awas 44% (high risk). In line B the highest risk in left hand was 53.19% (low risk) and inline A was 38% (low risk). The mean value of right and left hand exposure indices wasinsignificantly different (p<0.001). There was significant relationship between UEMSDs andhand type (p<0.001) and between UEMSDs and age (p<0.001).Conclusion: Line Ahad more risk than line B with respect to repetitive movements. In line Athe highest risk was in the right hand whereas in line B highest risk was seen in the left hand. Asthe most prevalent complaints were in wrists and fingers. We conclude that these parts are moreinvolved upper limbs in assembly line. Finally the OCRA method can be a useful method forevaluation of UEMSDs in repetitive tasks of the assembly industry