Vibration dose, a different approach to the subject

Abstract

The study of vibrations dates back to antiquity, analyzing at that time phenomena related to music, especially. However, only in recent decades have national and international bodies linked to health and safety been concerned about the damage resulting from these mechanical oscillations. In work environments, vibration exposure is typically transferred to the whole body. There are currently 58 countries that set limits for whole body vibration, and most of them adopt measurement methodologies described in Part one of the international standard ISO 2631-1:1997, and of these, the basic second power method (r.m.s., or root-mean square) is preferred worldwide. However, only 12% of analyzed countries adopt, albeit complementarily, the VDV (Vibration Dose Value), which uses acceleration to the fourth power, thus being much more sensitive to amplitude peaks, which tend to be a primary cause of discomfort. The longer a person is exposed to vibration, the lower the vibration intensity must be in order to preserve threshold criterion. For noise assessment, a dimensionless dose is calculated from the relationship between cut-off time and exposure time, and this dose is used to measure the risk of exposure. Using this same reasoning, a dimensionless dose for whole-body vibration was defined in this article and applied to known examples from technical guides. The results show that the new vibration dose approach is simpler and easier to interpret by occupational health and safety professionals, as well as by workers and employers. In addition, this metric, which is already used in noise dosimeters, could also be used in vibration meters.