Experimental Evaluation of Whole Body Vibration exposure from Tracked Excavators with Hydraulic Breaker Attachment in Rock Breaking operations

Ever expanding technological growth has led to an increase in the use of tracked excavators for construction, demolition, material handling, rock breaking etc. Excavator operators are exposed to a variety of risk factors that may lead to health problems. A major health hazard among operators is whole-body vibration. Human response to vibration is very complex and nonlinear. Whole Body Vibration in the range of 2 to 30 Hz corresponds to most of the resonant responses of various organs and parts of the human body. The objective of this paper is to assess whole body vibration for the tracked excavator with hydraulic breaker. The job safety analysis conducted through questionnaires for different industrial vehicle operators revealed the presence of a health risk among the operators in rock breaking machinery. To quantify the level of vibration, field tests are performed on four tracked excavators with hydraulic breaker attachments in two different work locations. Accelerometer, a real-time signal conditioning / processing and PULSE data acquisition software are used for vibration measurement. The frequency of vibration exposure is observed to be between 6.8 and 12 Hz. Acceleration levels measured were in the range of 0.87 -2.2 m/s(2) for a tracked excavator operator with breaker. The total vibration exposure calculated was between 0.621 and 1.932 m/s(2). The vibration dose value recorded was 17.6 -62.72 m/s(1.75). Whole body vibration exposure of the breaker operator was much higher and lies beyond the upper limit as given in ISO 2631-1. The ranges of vibration parameters measured were concomitant with frequent lower back pain, other muscular-skeletal injuries like leg pain etc which are prevalent among these operators.