Marjanen Y.

Long-term vibration measurements were made to several different mobile work machines at Finnish work sites. The measurements were made from two weeks to several months continuously using developed measuring device. The motivation for this study was to find out how much day-to-day variability there are in WBV exposure levels within the same machine or work phase during a longer period. Current ISO 2631-1 standard instructs to do at least three minutes of measurement to every work phase used for analysis. The results can then be used to represent an eight-hour work day and give an estimate of the health effects. The standard assumes that the vibration values from short-term measurements will represent the average exposure to human during normal work. There have not been many studies that would try to conclude if the short-term measurements of the daily exposure levels are enough to conclude the health effects of specific work environment. Several variables exists that can change the daily values, such as weather, changing work phases and road environment conditions. The variables can change the exposure values significantly and the short-term measurements may give a wrong impression of the vibration health risks in that work site. There is a need to do long-term measurements for certain types of work environments to have more specific information on vibration health risks.