Correlations in between EAWS and OCRA Index concerning the repetitive loads of the upper limbs in automobile manufacturing industries

Abstract

Upper limbs repetitive tasks are one of the main sources of risk for the workers of the manufacturing industries and the standards ISO 11228-3 and EN 1005-5 addressed this issue since 2007. EAWS (European Assembly Worksheet) is a 1st level ergonomic risk assessment method and it provides in its 4th section a score to measure the load level for the upper limbs based on a traffic light scheme. According to the relevant ISO/CEN standards, the OCRA Index is the preferred system to refer to in the evaluation of the biomechanical stress of hand-harm-shoulder system. This correlation study is based on a 45 workstations sample coming from the automobile manufacturing industry. According to the results, EAWS4 shows an excellent correlation with OCRA index (Spearman’s rho correlation index 0.95). Being EAWS based on biometric statistical data distribution, its typical application is the process design phase, but adopting a conservative approach in the interpretation of EAWS4 score for risk mapping purposes, it provides an equivalent “reaction” pattern (countermeasures to be taken in the production phase) with respect of OCRA Index with an Odds Ratio ranging from 0.89 (OR-matched) to 1.00 (OR-conservative).