Exposure of drivers of small roadsweepers to vibration

Status:

completed 06/2011

Aims:

In order for a risk assessment to be performed for the drivers of small roadsweepers, their vibration exposure on the driver's seat must be known. Additional stresses caused by poor body posture may exacerbate the vibration hazard.
This knowledge of the vibration exposure and body posture permits differentiation between workplaces with and without a whole-body vibration hazard and enables suitable preventive measures to be identified, such as the selection of suitable vibration-attenuating seats. For this last point, frequency-weighted accelerations at the seat mounting point and on the seat are important, as is the distribution of the vibration exposure values as a function of the excitation frequency.

Activities/Methods:

In response to an initiative by and in conjunction with a consortium of five German Social Accident Insurance Institutions for the public sector, small roadsweepers in five German cities were studied. Particular attention was paid to the operating states of driving and sweeping and to the road surfaces. Operating conditions were selected which apply to as many workplaces as possible.
The measurement points were the vibration transmission points of the seat mount/seat base and driver's seat/driver. The stress on the driver's seat and the damping characteristics of the seat were recorded. Altogether, 82 measurements were performed on roadsweepers up to a total weight of five tons. Where possible, the vibration exposure over entire shifts was recorded. The drivers' body posture was measured by random sampling.

Results:

The five municipal cleaning services concerned were provided with detailed data for risk assessment in accordance with the German Ordinance on noise and vibration protection. The data enabled the accident insurance institutions involved to provide information to other member companies for the purposes of risk assessment.

In two companies, additional control measurements were performed in order to check whether measures for vibration prevention were effective and to provide assistance during the purchase of new seats.

In order for the exposure transmitted through seats to be reduced, the seats should be adjusted to provide optimum vibration damping and should be designed in consideration of the vibration excitation caused by the vehicle.The measurements conducted during this project enabled the measured vibration excitation to be used for laboratory tests on seats and for standards organizations to be lobbied for the creation of a test standard for seats.

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