Lawnmower operators are exposed to high noise and hand-arm vibration (HAV) during their work, which originates mainly from the engine and rotating parts. Higher exposure causes intangible issues for the well-being of the operators, results in immediate and long-term effects on the health, comfort, and safety of the operators.
Objective
The study involved measuring noise and HAV from a powered cylindrical lawnmower, developing retrofittable interventions, and evaluating noise and HAV levels with the interventions, and compared their effectiveness using a health risk assessment.
Methods
The study was done at three speeds and two modes of operation. The measured noise and HAV amplitudes exceeded the permissible limits of international standards. Higher amplitudes were observed at resonant frequencies of the ear and hand. To mitigate the exposure and increase the safe working hours of the operators, two interventions were developed and retrofitted to the existing lawnmower. The noise and HAV were measured with interventions and compared against pre-intervention phase. Operator's physiological, psychophysical, and postural parameters were also assessed in the lawnmower operation.
Results
The developed interventions reduced the noise level from approximately 95 dB(A) to 85 dB(A), satisfying it within internationally permissible limits. HAV has been reduced from 23 ms–2 to below 10 ms–2, thereby increasing the safe exposure time by approximately 2.3 times with interventions. However, the operator's physiological, psychophysical, and postural parameters remained unchanged as operational requirements remained the same.
Conclusion
Noise and HAV reduction through interventions provided a safer working environment for the lawnmower operators.
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