title: Whole-body vibration in heavy equipment operators of a front-end loader: role of task exposure and tire configuration with and without traction chains.
abstract: BACKGROUND
  This study measured whole-body vibration (WBV) exposures in front-end loader operators, and evaluated the effects of traction chains and work tasks on their WBV exposures.
  
  
  METHODS
  WBV exposures were measured and compared across three different front-end loader tire configurations: (a) stock rubber tires, (b) rubber tires with ladder chains, and (c) rubber tires with basket chains. The operators completed three distinct standardized tasks: driving on a city street, simulated plowing, and a simulated scooping and dumping task. A portable data acquisition system collected tri-axial time weighted and raw WBV data per ISO 2631-1 and 2631-5 standards. In addition, Global Positioning System (GPS) data were collected in order to compare loader speeds across tire conditions and the standardized tasks.
  
  
  RESULTS
  Relative to the stock rubber tires, both types of tire chains significantly increased WBV exposures with the ladder chains having substantially higher WBV exposures compared to basket chains. Additionally, there were task dependent differences in WBV exposures. During the driving task, the z-axis (up and down) was the predominant exposure; the plowing task had a more even distribution of exposure across all three axes; while during scooping and dumping task, the x-axis (fore and aft) had the highest WBV exposures. The GPS data indicated that there were significant speed differences across tasks but not between the basket and ladder chain conditions.
  
  
  CONCLUSIONS
  Tires with ladder chains increased the front-end loader operators' exposure to WBV above the ISO 2631-1 recommended eight hour action limit increasing risk for adverse health effects. Although more expensive, basket chains are recommended over ladder chains since they substantially lowered the front-end loader operator's exposures and may ultimately reduce vibration related wear and tear on the vehicle.
  
  
  CONCLUSIONS
  In order to reduce a heavy equipment vehicle (HEV) operator's chances for developing low back pain, this study provides information that health and safety professionals can use to reduce whole-body vibration (WBV) exposures when operating front-end wheel loaders with traction chains.
authors.affiliation: University of Washington, School of Public Health, Department of Environmental and Occupational Health Sciences; Seattle, WA 98105, USA.
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Blood
authors.forename: Patrik W
authors.initials: PW
authors.lastname: Rynell
authors.forename: Peter W
authors.initials: PW
authors.lastname: Johnson
mesh_terms: D000328:Adult; D060389:Construction Industry; D004867:Equipment Design; D006801:Humans; D017116:Low Back Pain / Q000209:etiology / Q000517:prevention & control; D018986:Motor Vehicles; D016273:Occupational Exposure / Q000009:adverse effects* / Q000592:standards; D013647:Task Performance and Analysis; D014732:Vibration / Q000009:adverse effects*; D014937:Work