Simplify your work.
The vibrations that occur are measured as acceleration characteristics in the dimension m/s² in each of the three spatial directions x, y, z in a defined frequency range. A weighting factor is hereby taken into account for every frequency band to determine the effective values of the frequency-rated acceleration (ahwx, ahwy, ahwz). The total vibration value of the effective values of the frequency-weighted acceleration ahv is formed from the three acceleration characteristics with the equation A.
Equation A:
According to Equation B, the maximum possible exposure time can be calculated from the total vibration value of the effective values of the frequency-weighted acceleration relative to an eight hour working day.
Equation B:
A differentiation must be made between technical, organisational and personal vibration protection. Whereas personal vibration protection includes, for example, the wearing of anti-vibration gloves [1], an organisational measure can only reduce the daily load by reducing the daily exposure time. Vibrations can be reduced most effectively by technical vibration protection, i.e. the performance of technical vibration reduction measures directly at the tool [2].
In order to estimate the vibration load, the BGIA provides a characteristic value calculator that can be downloaded from the Internet, for example. General information and help on the topic of vibrations as well as the Noise and vibration occupational health and safety ordinance from March 2007 can be found on the Internet pages of the Berufgenossenschaft Metall Nord Süd
It appears significant that the vibrations which occur always represent system characteristic values. They are thus very dependent on the marginal conditions during work. Influencing parameters are the machine used (e.g. condition, basic vibrations), the workpiece to be processed (e.g. material, geometry), the user (e.g. weight, height, experience) himself and the tool used (unbalanced mass, hardness, wobble and eccentricity). This is shown in Figure 3.
- Figure 3: Influencing parameters for the occurring vibrations.
The load on the employee can be determined either by measurements at the workplace or from the manufacturer's data according to DIN5349-1 and 2. The problem here, however, is that the rated acceleration of angle grinders ahv in practical use can differ greatly from the vibration characteristic values declared by the manufacturer [3]. This is due to the alternative method used to determine the emission values (DIN EN ISO 8662-4 1995).
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[1]
Christ, E. - Personal protective equipment for vibration workplaces.
Sicherheitsingenieur 3/2007: 28-32. Haefner-Verlag, Heidelberg
[2]
Kaulbars, U. - Technical vibration protection for the effects of hand-arm vibrations.
In: BGIA-Manual Safety and Health Protection at Work 34 Lfg. VI/1999. Berufsgenossenschaftliches Institut für Arbeitsschutz – BGIA. 2003
[3]
Kaulbars, U. - Hand-arm vibrations when working with grinders. From the work of the BIA“, Berufsgenossenschaftliches Institut für Arbeitsschutz – BGIA. Edition 0163, 11/2001
