High impulse acceleration levels in hand-held vibratory tools. An additional factor in the hazards associated with the hand-arm vibration syndrome.

Abstract

The measurement of the root-mean-square (rms) acceleration of vibration does not take into consideration the short high peak values of the vibratory signal, which may be a hazard contributing to the development of vibration-induced disease. A method for evaluating the impulse character of vibratory signals is given, and impulsiveness is defined as the difference between the peak and rms signals. Measurements were taken during pedestal grinding, during chain sawing with 3 different generations of saws, and during chiseling with a pneumatic hammer. The measurements comprised analyses done according to the International Organization for Standardization (ISO) draft, an evaluation of impulsiveness, and an analysis of the short-time history transient. The risk of vibration-induced white fingers was estimated by the ISO method, and the results were compared with those observed. Analysis of impulsiveness provided additional data and partly explained the observed symptoms of vibration-induced white fingers. The parameters for the impulsiveness of the vibration signal agreed with the short-time history analysis.