Whole Body Vibration

Update on health hazards to heavy equipment operators

by Peter Vi, Hon. B.Sc.(Ergonomics), M.Eng., Project Coordinator, CSAO

 

Heavy equipment operators are exposed to vibration from bulldozers, backhoes, loaders, skid steer vehicles, excavators, and other construction machines.

 

The three main sources of whole body vibration from heavy equipment are

  • low-frequency vibration caused by tires and terrain
  • high-frequency vibration from engine and transmission
  • shock from running into potholes or obstacles.

For personnel operating heavy equipment, whole body vibration (WBV) is transmitted through supporting surfaces such as the feet of a standing person, the buttocks of a seated person, and the supporting areas of a reclining person.

Human response to WBV depends on the frequency of the vibration (measured in Hertz units—Hz), the acceleration (or magnitude in metres per seconds squared) of the vibration, and the duration of exposure to the vibration.

The health effects of WBV have been compared for operators of heavy equipment versus workers in a similar environment who were not exposed to WBV.

With short-term exposure to vibration in the 2-20 Hz range at 1 m/s2 (vibration magnitude) one can feel several different symptoms such as abdominal and chest pain, headaches, nausea, and loss of balance.

Long-term exposure to WBV can cause serious health problems, particularly with the spine:


Research

Through the cooperation of the Civil Engineering Labour-Management Health and Safety Committee, Laurentian University, and the International Union of Operating Engineers, CSAO has conducted numerous studies to quantify the vibration magnitude of common heavy equipment in construction (Figure 1).


Figure 1: Vibration magnitude for each type of construction equipment tested. For seven hours of continuous work, the magnitude of vibration should not exceed 0.8 m/s2.


Guidelines established by the International Standards Organization (ISO 2631) suggest that for seven hours of continuous work the magnitude of vibration should not exceed 0.8 m/s2. Looking at the data in Figure 1, we can see that most construction equipment (10 of 17 types) exceeded the health caution zone.

CSAO research also identified a significant difference in vibration magnitude between mobile equipment such as scrapers and bulldozers and stationary equipment such as excavators and cranes. Generally, mobile heavy equipment had a higher vibration magnitude than stationary equipment (Figure 2).



Figure 2: Mobile heavy equipment had a higher vibration magnitude than stationary equipment.


Recommendations

Until improved equipment is on the market, CSAO recommends the following measures to limit the whole body vibration experienced by heavy equipment operators.