Evaluation Methods for Vibration Effects

The sensation of horizontal vibration was equated to that of vertical vibration ofthe same frequency at 5, 10, 20, 30, 60, 100, 200 and 300 c/s. The sensation of verticalvibration above 5 c/s was found to be stronger than that of horizontal vibration by 10dB for sitting and by 13 dB for standing.Then, the horizontal vibrations from 0.5 to 200 c/s were equated in sensation withthe vertical vibration of 20 c/s at 30 dB (vibration acceleration level (VAL)) forsitting alone. The contours obtained in this experiment and the curves of the equalsensation for horizontal vibration on whole body are quite similar with each otherexcept that VAL at the standard frequency (20 c/s) of the latter is larger by 10 dBthan that of the former