Abstract:
Introduction: Exposure to whole-body vibration (WBV) has been associated with increased prevalence of low back pain in occupational settings. Not only does exposure to WBV have a high personal cost for workers who experience chronic pain, but it also has a high impact on the costs of workers’ compensation claims. Current guidelines, the International Standard of Mechanical Vibration and Shock (ISO 2631-1) are devoid of any identifiable or concrete recommendations for the length of time needed to accurately and reliably characterize a vehicle operator’s exposure to WBV. Determining and optimizing the required measurement duration period is needed to characterize a full-shift exposure for WBV exposure measurements as well as reducing the costs associated with assessing and addressing WBV-related issues. Methods: This study used tri-axial accelerometers with a GPS logger to measure WBV in regional 58 truck drivers for 64 full-shift samples. It focused on three WBV exposure parameters: root mean square weighted acceleration (Aw), vibration dose value (VDV), and the Seat Effective Amplitude Transmissibility (SEAT) ratio. Seat exposure measurements were taken in 3 axes (X, Y, and Z). Each full-shift sample was broken into segments of differing measurement durations (minutes) from the same common data collection starting point: (5, 7.5, 10, 15, 30, 60, 120, 240, 480) Using the GPS data, WBV exposure data was also characterized on the basis of whether the vehicle was moving or not moving. Results: The Z-axis was determined to be the predominant axis of exposure in this study. Aw exposures in the X- and Z- axes increased for the first 60 minutes. A follow up Tukey test showed that measurement durations of 30 minutes or longer in the predominant Z- axis were no different than the full-shift, 8-hour exposure measurement. This observation was supported for VDV and across the other axes. An analysis showed that the SEAT values should be based solely on WBV exposures during vehicle movement or SEAT values will likely be overestimated if based on moving and non-moving vehicle exposures. Discussion: In this study, the Aw analysis along the Z-axis showed that shorter durations of measurement exposure (30 minutes or longer) can accurately characterize the daily full-shift exposure of regional truck drivers. The analysis of the exposure data showed that SEAT values and VDV exposures should solely be based on the WBV exposures during vehicle movement. This methodology may be employed for other operators of other vehicle types and workers in other industry sectors.
URI
http://hdl.handle.net/1773/45992
