Elaboration of a standard procedure for the measurement of vibration emitted by percussive tools--application to breakers.

The Association Française de Normalisation (AFNOR) is preparing a standard on the exposure assessment of vibration from percussive tools. Therefore, a test code was developed for the measurement of vibration from percussive tools under laboratory conditions. The handle vibration from six different breakers, among which three tools were of "antivibration design," was measured with the following energy absorption methods: hydraulic base, steel shot, actual breaking of concrete, AFNOR concrete block, pointed chisel embedded in concrete. The last four methods were applied with breakers held by three successive operators. In addition, the first two were used with tools mounted in a rig which held them vertically and loaded them with a vertical downforce. The results indicated that the steel shot method was preferable although it gave 20% lower vibration results than those recorded for the actual breaking of concrete. It has the advantages of yielding consistent results with low scatter and being simple and cheap. Since difficulties have been experienced during the use of a pneumatic rig with breakers of antivibration design conception, the shot method should be applied with human operators.