Occupational risks related to vibrations using a brush cutter for green area management

Weed control is one of the most important issues in the maintenance sectors of both agriculture and green areas. Small tools are employed for controlling grass and other growths on steep verges and river banks. This leads the operators being exposed to many risks among which vibration is one. The purpose of this study is to measure and evaluate hand-arm vibration and to verify the daily exposure to which workers are often subjected while weeding.

Two cutting heads, a brush knife and a mowing head were compared. Both were mounted on the same cow-horn brush cutter. The vibration total value was expressed as the root-mean-square (rms) of three component values according to the axes X, Y and Z. The signal was frequency weighted using the weighting curve Wh, as described in the ISO 5349-1 (2001) standard. In addition, the daily vibration exposure was calculated and compared with the thresholds set by EU Directive 2002/44/EC (2005).

The obtained results showed that the exposure action value (EAV) of 2.5 ms^-2 was exceeded while using both cutting heads. The exposure limit value (ELV) using the brush knife also exceeded 5 ms^-2.

The results highlighted important aspects in terms of exposure values that should be considered with the view of preventing the risk of Hand-Arm Vibration Syndrome (HAVS) to which the operators who frequently use these tools are exposed. Specific measures should therefore be taken to protect the exposed workers.