Ergonomic - OCRA checklist risk assessment in the industry confection

Abstract

Introduction: The OCRA method is the reference method chosen in ISO (ISO 11228-3) and CEN (EN 1005-5) standards regarding risk assessment and management of upper limbs repetitive movements and exertions. The method consists of two specific tools (OCRA index and OCRA checklist). In this paper special attention will be devoted to the procedures for the analysis of multiple repetitive tasks. The Occupational Repetitive Actions (OCRA) - is a synthetic index describing risk factors of repetitive actions at work with one figure. The OCRA index quantifies the relationship between the daily numbers of actually performed by the upper limbs in repetitive tasks, and corresponding number of recommend actions: (total number of technical actions actually performed during the shift) / (total number of recommended technical actions during the shift). OCRA methods have been developed in Italy to analyze worker's exposure to tasks featuring various upper-limb injury risk factors. OCRA checklist is simpler and not so accurate than OCRA index. It can be used in risk evaluation to produce the fist “map of risks”. The present study object at to evaluate relationships between MSDs diagnosis and results of OCRA assessment. It also intends to analyses to the predictive validity of OCRA by confrontation with of video analyses results. Materials and methods: The study was performed on a group of 32 people working in the confection department. They work on two shifts of 8 hours each. We observed the workplace. We complied OCRA checklist; both filmed with the video camera the professional activity of some workers. Evaluation of the final checklist for the work (recovery score + frequency score + force score + posture score) x multiplier for the total duration of repetitive tasks. Results: Workers (42.0%) that present symptoms during one year were submitted to a clinical examination by a orthopedist to identify musculoskeletal diseases. OCRA checklist was applied in the same workplaces (62.3%) by two skilled ergonomists at the plant. Workplaces with moderate/high scores (n=57) on MSDs risk (OCRA checklist score >16.5) at elbow, wrist and fingers for means of OCRA predictive validity. The working activity requires the use of moderate force for (3 points on the Borg scale): Using tools, Pressing or handling components, Lifting or handling objects. OCRA checklist results it appears that OCRA has a broader scope due to the integration of four occupational hazards, including vibrations exposure, and provides a higher predictive validity. According to the results, observational risk assessment methods seems to be “useful” tools that should be valid and pointed to workplaces that workers are exposed to MSDs risk factors. Discrepancies in results between of MSDs risk assessment methods and clinically diagnosed MSDs cases should be analyzed and reflected that a minimalist approach or even simplistic, should, prima facie, to present results with similar levels of agreement. The risk factor "frequency of technical actions" or repetitively is crucial to the development of MSDs that is confirmed in our results (0.89), instead posture had just half of the weighting of OCRA score (0.42). Conclusions: All these processes, due to the duration, frequency of execution (hundreds of times per day) and the amplitude of the movements represent risk factors for the musculoskeletal disorders.