Upper limb disorders and hand-arm vibration risks with hand-held olive beaters

Abstract

Olive harvesting with hand-held beaters is a repetitive work, tiring and time consuming (more than 4–5 h/day). Operators work with vibrating tools in not natural body postures: they are therefore exposed to various risks, especially at the upper limbs. Unfortunately, also if in the agriculture sector the number of the declared upper limb disorders increased in the last years, hand-arm vibration and incongruent upper limb postures are not yet well perceived. In this work, the hand-arm vibration exposure and the OCRA index were calculated for five operators which used three different electric olive beaters. In all the observed tests both the hand-arm vibration and the OCRA scores produced results over the admitted limits. A(8) ranged between 8.6 ms-2 and 25.4 ms-2, far from the 5 ms-2 daily exposure limit values admitted by the European law (European Directive 2002/44). The OCRA checklist values ranged from a minimum value of 13.32 (red light level and light risk) for the left limb and a maximum of 34.41 (violet, high level and high risk) for the right limb. Relevance to industryThis paper describes the analysis of the combined risks to hand-arm vibration and to upper limb disorders in a typical agricultural harvesting task with a manual handled tool powered by electric engine. Tests were carried out during the olive harvesting with five operators using three different hand-held machines. Both vibration and OCRA parameters were acquired. Results showed that in all the observed tests both the hand-arm vibration and the OCRA scores were over the admitted limits. Beaters transmitted vibration to both the operators’ hand-arm system, but operators did not declare to perceive vibration at the right upper limb (because it was less affected by the vibration stimulus than the left one). To acquire reliable values for the upper limb biomechanical risk detection it should be necessary to use measured vibration data in field, avoiding personal judgments. When it is not possible to measure the vibration level, the employer should use the machine instruction, where the manufacturer should have written the vibration total value to which the hand-arm system is subjected, if it exceeds 2,5 m/s2 (European Directive 2006/42). When this information is not available in the machine instruction, the employer may refers to other sources (European Directive 2002/44), as databases provided by government or institutional bodies, including vibration values obtained by research specialists and vibration consultants.