Measuring method of driver's noise exposure for machine powered garden vehicles

When the noise exposure of the driver of a machine powered garden vehicle is measured, the results are greatly affected by the type of ground on which the measuring is performed. In the Nordic countries the changes of climate and snowing hinder the outdoor measurings, especially in winter. This study aimed at finding such a ground that it gives the same exposure values for the same machines and different measuring sites. Since the measuring results of sound pressure level LAeq using the same ground type in different countries with the same machines gave the highest and lowest levels differing as much as 3,3 dB, it was decided that the proposal for Nordtest should suggest an artificial surface. The acoustical properties of this measuring site flooring largely correspond to those of natural lawn, and both types of surfaces can be used during the test. The biggest deviation in measuring results between artificial surface and natural grass was l, 3 dB .