Influence of frequency weighting to VDI 2057-1:2002 upon the whole-body vibration exposure

Status:

completed 05/2004

Aims:

The new edition of VDI Guideline 2057-1:2002 governing the impact of human exposure to mechanical vibrations (whole-body vibration) has adopted amendments from the international standard ISO 2631-1:1997, "Evaluation of human exposure to whole-body vibration - Part 1: General Requirements". The changes include extension of the frequency range from 1-80 Hz to 0.5-80 Hz, and within this frequency range a change in the frequency weighting of the measured values for the vibration acceleration in the co-ordinate axes x, y and z (directions of measurement in relation to the human body). These changes result in both greater and smaller parameters than those previously measured for the vibration exposure on the seats of vehicles and mobile machinery. In order for data measured in the past to remain available for use in future hazard assessments and cases of formally recognized occupational diseases, conversion factors were to be defined.

Activities/Methods:

Based upon an initiative by the institutions for statutory accident insurance and prevention in the building trade, the impact data in the VIBEX database which were obtained using the previous frequency weighting were to be determined in accordance with the new frequency weighting, and the respective conversion factors determined by comparison. For this purpose, the vibration characteristics recorded in past measurements were being subjected to assessment with the new frequency weighting for vehicles and machines upon which a higher vibration exposure is generally to be anticipated. For vehicles and machines for which only a few measurements have been performed, new measurements were to be conducted with the support of the working group of the institutions for statutory accident insurance and prevention in the building trade, and assessed with both the former and the new frequency weighting. In order to deliver reliable conclusions, earlier measurements by the institution for statutory accident insurance and prevention in the mining industry were also to be considered in determination of the factors, the recorded vibration characteristics assessed with the new frequency weighting, and the factors calculated accordingly.

Results:

The comparative study found that the modified frequency weighting led to deviations from the vibration acceleration values measured in the past. The change in frequency weighting is generally seen to result in lower exposure for the vertical z-axis of vibration (the axis of the spine of a seated person) on the majority of wheeled vehicles, and in higher measured values on caterpillars. For the horizontal axes of vibration x and y, the values generally increase. The magnitude of the deviations in the measured vibration values is on the one hand specific to the vehicle group; on the other, deviations also vary within a given vehicle group as a function of the mode of operation, mass distribution, and suspension characteristics of the vehicles themselves and of their components. Mean correction factors were determined for the individual vehicle types. For the vertical axis of vibration (important for formally recognized occupational disease 2110), the factors lie between 0.9 and 1.15.

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